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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/core.c - core driver model code (device registration, etc)
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (c) 2006 Novell, Inc.
9 */
10
11#include <linux/acpi.h>
12#include <linux/cpufreq.h>
13#include <linux/device.h>
14#include <linux/err.h>
15#include <linux/fwnode.h>
16#include <linux/init.h>
17#include <linux/kstrtox.h>
18#include <linux/module.h>
19#include <linux/slab.h>
20#include <linux/kdev_t.h>
21#include <linux/notifier.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/blkdev.h>
25#include <linux/mutex.h>
26#include <linux/pm_runtime.h>
27#include <linux/netdevice.h>
28#include <linux/sched/signal.h>
29#include <linux/sched/mm.h>
30#include <linux/string_helpers.h>
31#include <linux/swiotlb.h>
32#include <linux/sysfs.h>
33#include <linux/dma-map-ops.h> /* for dma_default_coherent */
34
35#include "base.h"
36#include "physical_location.h"
37#include "power/power.h"
38
39/* Device links support. */
40static LIST_HEAD(deferred_sync);
41static unsigned int defer_sync_state_count = 1;
42static DEFINE_MUTEX(fwnode_link_lock);
43static bool fw_devlink_is_permissive(void);
44static void __fw_devlink_link_to_consumers(struct device *dev);
45static bool fw_devlink_drv_reg_done;
46static bool fw_devlink_best_effort;
47
48/**
49 * __fwnode_link_add - Create a link between two fwnode_handles.
50 * @con: Consumer end of the link.
51 * @sup: Supplier end of the link.
52 * @flags: Link flags.
53 *
54 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
55 * represents the detail that the firmware lists @sup fwnode as supplying a
56 * resource to @con.
57 *
58 * The driver core will use the fwnode link to create a device link between the
59 * two device objects corresponding to @con and @sup when they are created. The
60 * driver core will automatically delete the fwnode link between @con and @sup
61 * after doing that.
62 *
63 * Attempts to create duplicate links between the same pair of fwnode handles
64 * are ignored and there is no reference counting.
65 */
66static int __fwnode_link_add(struct fwnode_handle *con,
67 struct fwnode_handle *sup, u8 flags)
68{
69 struct fwnode_link *link;
70
71 list_for_each_entry(link, &sup->consumers, s_hook)
72 if (link->consumer == con) {
73 link->flags |= flags;
74 return 0;
75 }
76
77 link = kzalloc(sizeof(*link), GFP_KERNEL);
78 if (!link)
79 return -ENOMEM;
80
81 link->supplier = sup;
82 INIT_LIST_HEAD(&link->s_hook);
83 link->consumer = con;
84 INIT_LIST_HEAD(&link->c_hook);
85 link->flags = flags;
86
87 list_add(&link->s_hook, &sup->consumers);
88 list_add(&link->c_hook, &con->suppliers);
89 pr_debug("%pfwf Linked as a fwnode consumer to %pfwf\n",
90 con, sup);
91
92 return 0;
93}
94
95int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
96{
97 int ret;
98
99 mutex_lock(&fwnode_link_lock);
100 ret = __fwnode_link_add(con, sup, 0);
101 mutex_unlock(&fwnode_link_lock);
102 return ret;
103}
104
105/**
106 * __fwnode_link_del - Delete a link between two fwnode_handles.
107 * @link: the fwnode_link to be deleted
108 *
109 * The fwnode_link_lock needs to be held when this function is called.
110 */
111static void __fwnode_link_del(struct fwnode_link *link)
112{
113 pr_debug("%pfwf Dropping the fwnode link to %pfwf\n",
114 link->consumer, link->supplier);
115 list_del(&link->s_hook);
116 list_del(&link->c_hook);
117 kfree(link);
118}
119
120/**
121 * __fwnode_link_cycle - Mark a fwnode link as being part of a cycle.
122 * @link: the fwnode_link to be marked
123 *
124 * The fwnode_link_lock needs to be held when this function is called.
125 */
126static void __fwnode_link_cycle(struct fwnode_link *link)
127{
128 pr_debug("%pfwf: cycle: depends on %pfwf\n",
129 link->consumer, link->supplier);
130 link->flags |= FWLINK_FLAG_CYCLE;
131}
132
133/**
134 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
135 * @fwnode: fwnode whose supplier links need to be deleted
136 *
137 * Deletes all supplier links connecting directly to @fwnode.
138 */
139static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
140{
141 struct fwnode_link *link, *tmp;
142
143 mutex_lock(&fwnode_link_lock);
144 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
145 __fwnode_link_del(link);
146 mutex_unlock(&fwnode_link_lock);
147}
148
149/**
150 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
151 * @fwnode: fwnode whose consumer links need to be deleted
152 *
153 * Deletes all consumer links connecting directly to @fwnode.
154 */
155static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
156{
157 struct fwnode_link *link, *tmp;
158
159 mutex_lock(&fwnode_link_lock);
160 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
161 __fwnode_link_del(link);
162 mutex_unlock(&fwnode_link_lock);
163}
164
165/**
166 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
167 * @fwnode: fwnode whose links needs to be deleted
168 *
169 * Deletes all links connecting directly to a fwnode.
170 */
171void fwnode_links_purge(struct fwnode_handle *fwnode)
172{
173 fwnode_links_purge_suppliers(fwnode);
174 fwnode_links_purge_consumers(fwnode);
175}
176
177void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
178{
179 struct fwnode_handle *child;
180
181 /* Don't purge consumer links of an added child */
182 if (fwnode->dev)
183 return;
184
185 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
186 fwnode_links_purge_consumers(fwnode);
187
188 fwnode_for_each_available_child_node(fwnode, child)
189 fw_devlink_purge_absent_suppliers(child);
190}
191EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
192
193/**
194 * __fwnode_links_move_consumers - Move consumer from @from to @to fwnode_handle
195 * @from: move consumers away from this fwnode
196 * @to: move consumers to this fwnode
197 *
198 * Move all consumer links from @from fwnode to @to fwnode.
199 */
200static void __fwnode_links_move_consumers(struct fwnode_handle *from,
201 struct fwnode_handle *to)
202{
203 struct fwnode_link *link, *tmp;
204
205 list_for_each_entry_safe(link, tmp, &from->consumers, s_hook) {
206 __fwnode_link_add(link->consumer, to, link->flags);
207 __fwnode_link_del(link);
208 }
209}
210
211/**
212 * __fw_devlink_pickup_dangling_consumers - Pick up dangling consumers
213 * @fwnode: fwnode from which to pick up dangling consumers
214 * @new_sup: fwnode of new supplier
215 *
216 * If the @fwnode has a corresponding struct device and the device supports
217 * probing (that is, added to a bus), then we want to let fw_devlink create
218 * MANAGED device links to this device, so leave @fwnode and its descendant's
219 * fwnode links alone.
220 *
221 * Otherwise, move its consumers to the new supplier @new_sup.
222 */
223static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode,
224 struct fwnode_handle *new_sup)
225{
226 struct fwnode_handle *child;
227
228 if (fwnode->dev && fwnode->dev->bus)
229 return;
230
231 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
232 __fwnode_links_move_consumers(fwnode, new_sup);
233
234 fwnode_for_each_available_child_node(fwnode, child)
235 __fw_devlink_pickup_dangling_consumers(child, new_sup);
236}
237
238static DEFINE_MUTEX(device_links_lock);
239DEFINE_STATIC_SRCU(device_links_srcu);
240
241static inline void device_links_write_lock(void)
242{
243 mutex_lock(&device_links_lock);
244}
245
246static inline void device_links_write_unlock(void)
247{
248 mutex_unlock(&device_links_lock);
249}
250
251int device_links_read_lock(void) __acquires(&device_links_srcu)
252{
253 return srcu_read_lock(&device_links_srcu);
254}
255
256void device_links_read_unlock(int idx) __releases(&device_links_srcu)
257{
258 srcu_read_unlock(&device_links_srcu, idx);
259}
260
261int device_links_read_lock_held(void)
262{
263 return srcu_read_lock_held(&device_links_srcu);
264}
265
266static void device_link_synchronize_removal(void)
267{
268 synchronize_srcu(&device_links_srcu);
269}
270
271static void device_link_remove_from_lists(struct device_link *link)
272{
273 list_del_rcu(&link->s_node);
274 list_del_rcu(&link->c_node);
275}
276
277static bool device_is_ancestor(struct device *dev, struct device *target)
278{
279 while (target->parent) {
280 target = target->parent;
281 if (dev == target)
282 return true;
283 }
284 return false;
285}
286
287#define DL_MARKER_FLAGS (DL_FLAG_INFERRED | \
288 DL_FLAG_CYCLE | \
289 DL_FLAG_MANAGED)
290static inline bool device_link_flag_is_sync_state_only(u32 flags)
291{
292 return (flags & ~DL_MARKER_FLAGS) == DL_FLAG_SYNC_STATE_ONLY;
293}
294
295/**
296 * device_is_dependent - Check if one device depends on another one
297 * @dev: Device to check dependencies for.
298 * @target: Device to check against.
299 *
300 * Check if @target depends on @dev or any device dependent on it (its child or
301 * its consumer etc). Return 1 if that is the case or 0 otherwise.
302 */
303static int device_is_dependent(struct device *dev, void *target)
304{
305 struct device_link *link;
306 int ret;
307
308 /*
309 * The "ancestors" check is needed to catch the case when the target
310 * device has not been completely initialized yet and it is still
311 * missing from the list of children of its parent device.
312 */
313 if (dev == target || device_is_ancestor(dev, target))
314 return 1;
315
316 ret = device_for_each_child(dev, target, device_is_dependent);
317 if (ret)
318 return ret;
319
320 list_for_each_entry(link, &dev->links.consumers, s_node) {
321 if (device_link_flag_is_sync_state_only(link->flags))
322 continue;
323
324 if (link->consumer == target)
325 return 1;
326
327 ret = device_is_dependent(link->consumer, target);
328 if (ret)
329 break;
330 }
331 return ret;
332}
333
334static void device_link_init_status(struct device_link *link,
335 struct device *consumer,
336 struct device *supplier)
337{
338 switch (supplier->links.status) {
339 case DL_DEV_PROBING:
340 switch (consumer->links.status) {
341 case DL_DEV_PROBING:
342 /*
343 * A consumer driver can create a link to a supplier
344 * that has not completed its probing yet as long as it
345 * knows that the supplier is already functional (for
346 * example, it has just acquired some resources from the
347 * supplier).
348 */
349 link->status = DL_STATE_CONSUMER_PROBE;
350 break;
351 default:
352 link->status = DL_STATE_DORMANT;
353 break;
354 }
355 break;
356 case DL_DEV_DRIVER_BOUND:
357 switch (consumer->links.status) {
358 case DL_DEV_PROBING:
359 link->status = DL_STATE_CONSUMER_PROBE;
360 break;
361 case DL_DEV_DRIVER_BOUND:
362 link->status = DL_STATE_ACTIVE;
363 break;
364 default:
365 link->status = DL_STATE_AVAILABLE;
366 break;
367 }
368 break;
369 case DL_DEV_UNBINDING:
370 link->status = DL_STATE_SUPPLIER_UNBIND;
371 break;
372 default:
373 link->status = DL_STATE_DORMANT;
374 break;
375 }
376}
377
378static int device_reorder_to_tail(struct device *dev, void *not_used)
379{
380 struct device_link *link;
381
382 /*
383 * Devices that have not been registered yet will be put to the ends
384 * of the lists during the registration, so skip them here.
385 */
386 if (device_is_registered(dev))
387 devices_kset_move_last(dev);
388
389 if (device_pm_initialized(dev))
390 device_pm_move_last(dev);
391
392 device_for_each_child(dev, NULL, device_reorder_to_tail);
393 list_for_each_entry(link, &dev->links.consumers, s_node) {
394 if (device_link_flag_is_sync_state_only(link->flags))
395 continue;
396 device_reorder_to_tail(link->consumer, NULL);
397 }
398
399 return 0;
400}
401
402/**
403 * device_pm_move_to_tail - Move set of devices to the end of device lists
404 * @dev: Device to move
405 *
406 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
407 *
408 * It moves the @dev along with all of its children and all of its consumers
409 * to the ends of the device_kset and dpm_list, recursively.
410 */
411void device_pm_move_to_tail(struct device *dev)
412{
413 int idx;
414
415 idx = device_links_read_lock();
416 device_pm_lock();
417 device_reorder_to_tail(dev, NULL);
418 device_pm_unlock();
419 device_links_read_unlock(idx);
420}
421
422#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
423
424static ssize_t status_show(struct device *dev,
425 struct device_attribute *attr, char *buf)
426{
427 const char *output;
428
429 switch (to_devlink(dev)->status) {
430 case DL_STATE_NONE:
431 output = "not tracked";
432 break;
433 case DL_STATE_DORMANT:
434 output = "dormant";
435 break;
436 case DL_STATE_AVAILABLE:
437 output = "available";
438 break;
439 case DL_STATE_CONSUMER_PROBE:
440 output = "consumer probing";
441 break;
442 case DL_STATE_ACTIVE:
443 output = "active";
444 break;
445 case DL_STATE_SUPPLIER_UNBIND:
446 output = "supplier unbinding";
447 break;
448 default:
449 output = "unknown";
450 break;
451 }
452
453 return sysfs_emit(buf, "%s\n", output);
454}
455static DEVICE_ATTR_RO(status);
456
457static ssize_t auto_remove_on_show(struct device *dev,
458 struct device_attribute *attr, char *buf)
459{
460 struct device_link *link = to_devlink(dev);
461 const char *output;
462
463 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
464 output = "supplier unbind";
465 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
466 output = "consumer unbind";
467 else
468 output = "never";
469
470 return sysfs_emit(buf, "%s\n", output);
471}
472static DEVICE_ATTR_RO(auto_remove_on);
473
474static ssize_t runtime_pm_show(struct device *dev,
475 struct device_attribute *attr, char *buf)
476{
477 struct device_link *link = to_devlink(dev);
478
479 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
480}
481static DEVICE_ATTR_RO(runtime_pm);
482
483static ssize_t sync_state_only_show(struct device *dev,
484 struct device_attribute *attr, char *buf)
485{
486 struct device_link *link = to_devlink(dev);
487
488 return sysfs_emit(buf, "%d\n",
489 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
490}
491static DEVICE_ATTR_RO(sync_state_only);
492
493static struct attribute *devlink_attrs[] = {
494 &dev_attr_status.attr,
495 &dev_attr_auto_remove_on.attr,
496 &dev_attr_runtime_pm.attr,
497 &dev_attr_sync_state_only.attr,
498 NULL,
499};
500ATTRIBUTE_GROUPS(devlink);
501
502static void device_link_release_fn(struct work_struct *work)
503{
504 struct device_link *link = container_of(work, struct device_link, rm_work);
505
506 /* Ensure that all references to the link object have been dropped. */
507 device_link_synchronize_removal();
508
509 pm_runtime_release_supplier(link);
510 /*
511 * If supplier_preactivated is set, the link has been dropped between
512 * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
513 * in __driver_probe_device(). In that case, drop the supplier's
514 * PM-runtime usage counter to remove the reference taken by
515 * pm_runtime_get_suppliers().
516 */
517 if (link->supplier_preactivated)
518 pm_runtime_put_noidle(link->supplier);
519
520 pm_request_idle(link->supplier);
521
522 put_device(link->consumer);
523 put_device(link->supplier);
524 kfree(link);
525}
526
527static void devlink_dev_release(struct device *dev)
528{
529 struct device_link *link = to_devlink(dev);
530
531 INIT_WORK(&link->rm_work, device_link_release_fn);
532 /*
533 * It may take a while to complete this work because of the SRCU
534 * synchronization in device_link_release_fn() and if the consumer or
535 * supplier devices get deleted when it runs, so put it into the "long"
536 * workqueue.
537 */
538 queue_work(system_long_wq, &link->rm_work);
539}
540
541static struct class devlink_class = {
542 .name = "devlink",
543 .dev_groups = devlink_groups,
544 .dev_release = devlink_dev_release,
545};
546
547static int devlink_add_symlinks(struct device *dev)
548{
549 int ret;
550 size_t len;
551 struct device_link *link = to_devlink(dev);
552 struct device *sup = link->supplier;
553 struct device *con = link->consumer;
554 char *buf;
555
556 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
557 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
558 len += strlen(":");
559 len += strlen("supplier:") + 1;
560 buf = kzalloc(len, GFP_KERNEL);
561 if (!buf)
562 return -ENOMEM;
563
564 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
565 if (ret)
566 goto out;
567
568 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
569 if (ret)
570 goto err_con;
571
572 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
573 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
574 if (ret)
575 goto err_con_dev;
576
577 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
578 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
579 if (ret)
580 goto err_sup_dev;
581
582 goto out;
583
584err_sup_dev:
585 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
586 sysfs_remove_link(&sup->kobj, buf);
587err_con_dev:
588 sysfs_remove_link(&link->link_dev.kobj, "consumer");
589err_con:
590 sysfs_remove_link(&link->link_dev.kobj, "supplier");
591out:
592 kfree(buf);
593 return ret;
594}
595
596static void devlink_remove_symlinks(struct device *dev)
597{
598 struct device_link *link = to_devlink(dev);
599 size_t len;
600 struct device *sup = link->supplier;
601 struct device *con = link->consumer;
602 char *buf;
603
604 sysfs_remove_link(&link->link_dev.kobj, "consumer");
605 sysfs_remove_link(&link->link_dev.kobj, "supplier");
606
607 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
608 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
609 len += strlen(":");
610 len += strlen("supplier:") + 1;
611 buf = kzalloc(len, GFP_KERNEL);
612 if (!buf) {
613 WARN(1, "Unable to properly free device link symlinks!\n");
614 return;
615 }
616
617 if (device_is_registered(con)) {
618 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
619 sysfs_remove_link(&con->kobj, buf);
620 }
621 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
622 sysfs_remove_link(&sup->kobj, buf);
623 kfree(buf);
624}
625
626static struct class_interface devlink_class_intf = {
627 .class = &devlink_class,
628 .add_dev = devlink_add_symlinks,
629 .remove_dev = devlink_remove_symlinks,
630};
631
632static int __init devlink_class_init(void)
633{
634 int ret;
635
636 ret = class_register(&devlink_class);
637 if (ret)
638 return ret;
639
640 ret = class_interface_register(&devlink_class_intf);
641 if (ret)
642 class_unregister(&devlink_class);
643
644 return ret;
645}
646postcore_initcall(devlink_class_init);
647
648#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
649 DL_FLAG_AUTOREMOVE_SUPPLIER | \
650 DL_FLAG_AUTOPROBE_CONSUMER | \
651 DL_FLAG_SYNC_STATE_ONLY | \
652 DL_FLAG_INFERRED | \
653 DL_FLAG_CYCLE)
654
655#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
656 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
657
658/**
659 * device_link_add - Create a link between two devices.
660 * @consumer: Consumer end of the link.
661 * @supplier: Supplier end of the link.
662 * @flags: Link flags.
663 *
664 * The caller is responsible for the proper synchronization of the link creation
665 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
666 * runtime PM framework to take the link into account. Second, if the
667 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
668 * be forced into the active meta state and reference-counted upon the creation
669 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
670 * ignored.
671 *
672 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
673 * expected to release the link returned by it directly with the help of either
674 * device_link_del() or device_link_remove().
675 *
676 * If that flag is not set, however, the caller of this function is handing the
677 * management of the link over to the driver core entirely and its return value
678 * can only be used to check whether or not the link is present. In that case,
679 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
680 * flags can be used to indicate to the driver core when the link can be safely
681 * deleted. Namely, setting one of them in @flags indicates to the driver core
682 * that the link is not going to be used (by the given caller of this function)
683 * after unbinding the consumer or supplier driver, respectively, from its
684 * device, so the link can be deleted at that point. If none of them is set,
685 * the link will be maintained until one of the devices pointed to by it (either
686 * the consumer or the supplier) is unregistered.
687 *
688 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
689 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
690 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
691 * be used to request the driver core to automatically probe for a consumer
692 * driver after successfully binding a driver to the supplier device.
693 *
694 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
695 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
696 * the same time is invalid and will cause NULL to be returned upfront.
697 * However, if a device link between the given @consumer and @supplier pair
698 * exists already when this function is called for them, the existing link will
699 * be returned regardless of its current type and status (the link's flags may
700 * be modified then). The caller of this function is then expected to treat
701 * the link as though it has just been created, so (in particular) if
702 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
703 * explicitly when not needed any more (as stated above).
704 *
705 * A side effect of the link creation is re-ordering of dpm_list and the
706 * devices_kset list by moving the consumer device and all devices depending
707 * on it to the ends of these lists (that does not happen to devices that have
708 * not been registered when this function is called).
709 *
710 * The supplier device is required to be registered when this function is called
711 * and NULL will be returned if that is not the case. The consumer device need
712 * not be registered, however.
713 */
714struct device_link *device_link_add(struct device *consumer,
715 struct device *supplier, u32 flags)
716{
717 struct device_link *link;
718
719 if (!consumer || !supplier || consumer == supplier ||
720 flags & ~DL_ADD_VALID_FLAGS ||
721 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
722 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
723 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
724 DL_FLAG_AUTOREMOVE_SUPPLIER)))
725 return NULL;
726
727 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
728 if (pm_runtime_get_sync(supplier) < 0) {
729 pm_runtime_put_noidle(supplier);
730 return NULL;
731 }
732 }
733
734 if (!(flags & DL_FLAG_STATELESS))
735 flags |= DL_FLAG_MANAGED;
736
737 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
738 !device_link_flag_is_sync_state_only(flags))
739 return NULL;
740
741 device_links_write_lock();
742 device_pm_lock();
743
744 /*
745 * If the supplier has not been fully registered yet or there is a
746 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
747 * the supplier already in the graph, return NULL. If the link is a
748 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
749 * because it only affects sync_state() callbacks.
750 */
751 if (!device_pm_initialized(supplier)
752 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
753 device_is_dependent(consumer, supplier))) {
754 link = NULL;
755 goto out;
756 }
757
758 /*
759 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
760 * So, only create it if the consumer hasn't probed yet.
761 */
762 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
763 consumer->links.status != DL_DEV_NO_DRIVER &&
764 consumer->links.status != DL_DEV_PROBING) {
765 link = NULL;
766 goto out;
767 }
768
769 /*
770 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
771 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
772 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
773 */
774 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
775 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
776
777 list_for_each_entry(link, &supplier->links.consumers, s_node) {
778 if (link->consumer != consumer)
779 continue;
780
781 if (link->flags & DL_FLAG_INFERRED &&
782 !(flags & DL_FLAG_INFERRED))
783 link->flags &= ~DL_FLAG_INFERRED;
784
785 if (flags & DL_FLAG_PM_RUNTIME) {
786 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
787 pm_runtime_new_link(consumer);
788 link->flags |= DL_FLAG_PM_RUNTIME;
789 }
790 if (flags & DL_FLAG_RPM_ACTIVE)
791 refcount_inc(&link->rpm_active);
792 }
793
794 if (flags & DL_FLAG_STATELESS) {
795 kref_get(&link->kref);
796 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
797 !(link->flags & DL_FLAG_STATELESS)) {
798 link->flags |= DL_FLAG_STATELESS;
799 goto reorder;
800 } else {
801 link->flags |= DL_FLAG_STATELESS;
802 goto out;
803 }
804 }
805
806 /*
807 * If the life time of the link following from the new flags is
808 * longer than indicated by the flags of the existing link,
809 * update the existing link to stay around longer.
810 */
811 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
812 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
813 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
814 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
815 }
816 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
817 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
818 DL_FLAG_AUTOREMOVE_SUPPLIER);
819 }
820 if (!(link->flags & DL_FLAG_MANAGED)) {
821 kref_get(&link->kref);
822 link->flags |= DL_FLAG_MANAGED;
823 device_link_init_status(link, consumer, supplier);
824 }
825 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
826 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
827 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
828 goto reorder;
829 }
830
831 goto out;
832 }
833
834 link = kzalloc(sizeof(*link), GFP_KERNEL);
835 if (!link)
836 goto out;
837
838 refcount_set(&link->rpm_active, 1);
839
840 get_device(supplier);
841 link->supplier = supplier;
842 INIT_LIST_HEAD(&link->s_node);
843 get_device(consumer);
844 link->consumer = consumer;
845 INIT_LIST_HEAD(&link->c_node);
846 link->flags = flags;
847 kref_init(&link->kref);
848
849 link->link_dev.class = &devlink_class;
850 device_set_pm_not_required(&link->link_dev);
851 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
852 dev_bus_name(supplier), dev_name(supplier),
853 dev_bus_name(consumer), dev_name(consumer));
854 if (device_register(&link->link_dev)) {
855 put_device(&link->link_dev);
856 link = NULL;
857 goto out;
858 }
859
860 if (flags & DL_FLAG_PM_RUNTIME) {
861 if (flags & DL_FLAG_RPM_ACTIVE)
862 refcount_inc(&link->rpm_active);
863
864 pm_runtime_new_link(consumer);
865 }
866
867 /* Determine the initial link state. */
868 if (flags & DL_FLAG_STATELESS)
869 link->status = DL_STATE_NONE;
870 else
871 device_link_init_status(link, consumer, supplier);
872
873 /*
874 * Some callers expect the link creation during consumer driver probe to
875 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
876 */
877 if (link->status == DL_STATE_CONSUMER_PROBE &&
878 flags & DL_FLAG_PM_RUNTIME)
879 pm_runtime_resume(supplier);
880
881 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
882 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
883
884 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
885 dev_dbg(consumer,
886 "Linked as a sync state only consumer to %s\n",
887 dev_name(supplier));
888 goto out;
889 }
890
891reorder:
892 /*
893 * Move the consumer and all of the devices depending on it to the end
894 * of dpm_list and the devices_kset list.
895 *
896 * It is necessary to hold dpm_list locked throughout all that or else
897 * we may end up suspending with a wrong ordering of it.
898 */
899 device_reorder_to_tail(consumer, NULL);
900
901 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
902
903out:
904 device_pm_unlock();
905 device_links_write_unlock();
906
907 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
908 pm_runtime_put(supplier);
909
910 return link;
911}
912EXPORT_SYMBOL_GPL(device_link_add);
913
914static void __device_link_del(struct kref *kref)
915{
916 struct device_link *link = container_of(kref, struct device_link, kref);
917
918 dev_dbg(link->consumer, "Dropping the link to %s\n",
919 dev_name(link->supplier));
920
921 pm_runtime_drop_link(link);
922
923 device_link_remove_from_lists(link);
924 device_unregister(&link->link_dev);
925}
926
927static void device_link_put_kref(struct device_link *link)
928{
929 if (link->flags & DL_FLAG_STATELESS)
930 kref_put(&link->kref, __device_link_del);
931 else if (!device_is_registered(link->consumer))
932 __device_link_del(&link->kref);
933 else
934 WARN(1, "Unable to drop a managed device link reference\n");
935}
936
937/**
938 * device_link_del - Delete a stateless link between two devices.
939 * @link: Device link to delete.
940 *
941 * The caller must ensure proper synchronization of this function with runtime
942 * PM. If the link was added multiple times, it needs to be deleted as often.
943 * Care is required for hotplugged devices: Their links are purged on removal
944 * and calling device_link_del() is then no longer allowed.
945 */
946void device_link_del(struct device_link *link)
947{
948 device_links_write_lock();
949 device_link_put_kref(link);
950 device_links_write_unlock();
951}
952EXPORT_SYMBOL_GPL(device_link_del);
953
954/**
955 * device_link_remove - Delete a stateless link between two devices.
956 * @consumer: Consumer end of the link.
957 * @supplier: Supplier end of the link.
958 *
959 * The caller must ensure proper synchronization of this function with runtime
960 * PM.
961 */
962void device_link_remove(void *consumer, struct device *supplier)
963{
964 struct device_link *link;
965
966 if (WARN_ON(consumer == supplier))
967 return;
968
969 device_links_write_lock();
970
971 list_for_each_entry(link, &supplier->links.consumers, s_node) {
972 if (link->consumer == consumer) {
973 device_link_put_kref(link);
974 break;
975 }
976 }
977
978 device_links_write_unlock();
979}
980EXPORT_SYMBOL_GPL(device_link_remove);
981
982static void device_links_missing_supplier(struct device *dev)
983{
984 struct device_link *link;
985
986 list_for_each_entry(link, &dev->links.suppliers, c_node) {
987 if (link->status != DL_STATE_CONSUMER_PROBE)
988 continue;
989
990 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
991 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
992 } else {
993 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
994 WRITE_ONCE(link->status, DL_STATE_DORMANT);
995 }
996 }
997}
998
999static bool dev_is_best_effort(struct device *dev)
1000{
1001 return (fw_devlink_best_effort && dev->can_match) ||
1002 (dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
1003}
1004
1005static struct fwnode_handle *fwnode_links_check_suppliers(
1006 struct fwnode_handle *fwnode)
1007{
1008 struct fwnode_link *link;
1009
1010 if (!fwnode || fw_devlink_is_permissive())
1011 return NULL;
1012
1013 list_for_each_entry(link, &fwnode->suppliers, c_hook)
1014 if (!(link->flags & FWLINK_FLAG_CYCLE))
1015 return link->supplier;
1016
1017 return NULL;
1018}
1019
1020/**
1021 * device_links_check_suppliers - Check presence of supplier drivers.
1022 * @dev: Consumer device.
1023 *
1024 * Check links from this device to any suppliers. Walk the list of the device's
1025 * links to suppliers and see if all of them are available. If not, simply
1026 * return -EPROBE_DEFER.
1027 *
1028 * We need to guarantee that the supplier will not go away after the check has
1029 * been positive here. It only can go away in __device_release_driver() and
1030 * that function checks the device's links to consumers. This means we need to
1031 * mark the link as "consumer probe in progress" to make the supplier removal
1032 * wait for us to complete (or bad things may happen).
1033 *
1034 * Links without the DL_FLAG_MANAGED flag set are ignored.
1035 */
1036int device_links_check_suppliers(struct device *dev)
1037{
1038 struct device_link *link;
1039 int ret = 0, fwnode_ret = 0;
1040 struct fwnode_handle *sup_fw;
1041
1042 /*
1043 * Device waiting for supplier to become available is not allowed to
1044 * probe.
1045 */
1046 mutex_lock(&fwnode_link_lock);
1047 sup_fw = fwnode_links_check_suppliers(dev->fwnode);
1048 if (sup_fw) {
1049 if (!dev_is_best_effort(dev)) {
1050 fwnode_ret = -EPROBE_DEFER;
1051 dev_err_probe(dev, -EPROBE_DEFER,
1052 "wait for supplier %pfwf\n", sup_fw);
1053 } else {
1054 fwnode_ret = -EAGAIN;
1055 }
1056 }
1057 mutex_unlock(&fwnode_link_lock);
1058 if (fwnode_ret == -EPROBE_DEFER)
1059 return fwnode_ret;
1060
1061 device_links_write_lock();
1062
1063 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1064 if (!(link->flags & DL_FLAG_MANAGED))
1065 continue;
1066
1067 if (link->status != DL_STATE_AVAILABLE &&
1068 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1069
1070 if (dev_is_best_effort(dev) &&
1071 link->flags & DL_FLAG_INFERRED &&
1072 !link->supplier->can_match) {
1073 ret = -EAGAIN;
1074 continue;
1075 }
1076
1077 device_links_missing_supplier(dev);
1078 dev_err_probe(dev, -EPROBE_DEFER,
1079 "supplier %s not ready\n",
1080 dev_name(link->supplier));
1081 ret = -EPROBE_DEFER;
1082 break;
1083 }
1084 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1085 }
1086 dev->links.status = DL_DEV_PROBING;
1087
1088 device_links_write_unlock();
1089
1090 return ret ? ret : fwnode_ret;
1091}
1092
1093/**
1094 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1095 * @dev: Device to call sync_state() on
1096 * @list: List head to queue the @dev on
1097 *
1098 * Queues a device for a sync_state() callback when the device links write lock
1099 * isn't held. This allows the sync_state() execution flow to use device links
1100 * APIs. The caller must ensure this function is called with
1101 * device_links_write_lock() held.
1102 *
1103 * This function does a get_device() to make sure the device is not freed while
1104 * on this list.
1105 *
1106 * So the caller must also ensure that device_links_flush_sync_list() is called
1107 * as soon as the caller releases device_links_write_lock(). This is necessary
1108 * to make sure the sync_state() is called in a timely fashion and the
1109 * put_device() is called on this device.
1110 */
1111static void __device_links_queue_sync_state(struct device *dev,
1112 struct list_head *list)
1113{
1114 struct device_link *link;
1115
1116 if (!dev_has_sync_state(dev))
1117 return;
1118 if (dev->state_synced)
1119 return;
1120
1121 list_for_each_entry(link, &dev->links.consumers, s_node) {
1122 if (!(link->flags & DL_FLAG_MANAGED))
1123 continue;
1124 if (link->status != DL_STATE_ACTIVE)
1125 return;
1126 }
1127
1128 /*
1129 * Set the flag here to avoid adding the same device to a list more
1130 * than once. This can happen if new consumers get added to the device
1131 * and probed before the list is flushed.
1132 */
1133 dev->state_synced = true;
1134
1135 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1136 return;
1137
1138 get_device(dev);
1139 list_add_tail(&dev->links.defer_sync, list);
1140}
1141
1142/**
1143 * device_links_flush_sync_list - Call sync_state() on a list of devices
1144 * @list: List of devices to call sync_state() on
1145 * @dont_lock_dev: Device for which lock is already held by the caller
1146 *
1147 * Calls sync_state() on all the devices that have been queued for it. This
1148 * function is used in conjunction with __device_links_queue_sync_state(). The
1149 * @dont_lock_dev parameter is useful when this function is called from a
1150 * context where a device lock is already held.
1151 */
1152static void device_links_flush_sync_list(struct list_head *list,
1153 struct device *dont_lock_dev)
1154{
1155 struct device *dev, *tmp;
1156
1157 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1158 list_del_init(&dev->links.defer_sync);
1159
1160 if (dev != dont_lock_dev)
1161 device_lock(dev);
1162
1163 dev_sync_state(dev);
1164
1165 if (dev != dont_lock_dev)
1166 device_unlock(dev);
1167
1168 put_device(dev);
1169 }
1170}
1171
1172void device_links_supplier_sync_state_pause(void)
1173{
1174 device_links_write_lock();
1175 defer_sync_state_count++;
1176 device_links_write_unlock();
1177}
1178
1179void device_links_supplier_sync_state_resume(void)
1180{
1181 struct device *dev, *tmp;
1182 LIST_HEAD(sync_list);
1183
1184 device_links_write_lock();
1185 if (!defer_sync_state_count) {
1186 WARN(true, "Unmatched sync_state pause/resume!");
1187 goto out;
1188 }
1189 defer_sync_state_count--;
1190 if (defer_sync_state_count)
1191 goto out;
1192
1193 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1194 /*
1195 * Delete from deferred_sync list before queuing it to
1196 * sync_list because defer_sync is used for both lists.
1197 */
1198 list_del_init(&dev->links.defer_sync);
1199 __device_links_queue_sync_state(dev, &sync_list);
1200 }
1201out:
1202 device_links_write_unlock();
1203
1204 device_links_flush_sync_list(&sync_list, NULL);
1205}
1206
1207static int sync_state_resume_initcall(void)
1208{
1209 device_links_supplier_sync_state_resume();
1210 return 0;
1211}
1212late_initcall(sync_state_resume_initcall);
1213
1214static void __device_links_supplier_defer_sync(struct device *sup)
1215{
1216 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1217 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1218}
1219
1220static void device_link_drop_managed(struct device_link *link)
1221{
1222 link->flags &= ~DL_FLAG_MANAGED;
1223 WRITE_ONCE(link->status, DL_STATE_NONE);
1224 kref_put(&link->kref, __device_link_del);
1225}
1226
1227static ssize_t waiting_for_supplier_show(struct device *dev,
1228 struct device_attribute *attr,
1229 char *buf)
1230{
1231 bool val;
1232
1233 device_lock(dev);
1234 mutex_lock(&fwnode_link_lock);
1235 val = !!fwnode_links_check_suppliers(dev->fwnode);
1236 mutex_unlock(&fwnode_link_lock);
1237 device_unlock(dev);
1238 return sysfs_emit(buf, "%u\n", val);
1239}
1240static DEVICE_ATTR_RO(waiting_for_supplier);
1241
1242/**
1243 * device_links_force_bind - Prepares device to be force bound
1244 * @dev: Consumer device.
1245 *
1246 * device_bind_driver() force binds a device to a driver without calling any
1247 * driver probe functions. So the consumer really isn't going to wait for any
1248 * supplier before it's bound to the driver. We still want the device link
1249 * states to be sensible when this happens.
1250 *
1251 * In preparation for device_bind_driver(), this function goes through each
1252 * supplier device links and checks if the supplier is bound. If it is, then
1253 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1254 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1255 */
1256void device_links_force_bind(struct device *dev)
1257{
1258 struct device_link *link, *ln;
1259
1260 device_links_write_lock();
1261
1262 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1263 if (!(link->flags & DL_FLAG_MANAGED))
1264 continue;
1265
1266 if (link->status != DL_STATE_AVAILABLE) {
1267 device_link_drop_managed(link);
1268 continue;
1269 }
1270 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1271 }
1272 dev->links.status = DL_DEV_PROBING;
1273
1274 device_links_write_unlock();
1275}
1276
1277/**
1278 * device_links_driver_bound - Update device links after probing its driver.
1279 * @dev: Device to update the links for.
1280 *
1281 * The probe has been successful, so update links from this device to any
1282 * consumers by changing their status to "available".
1283 *
1284 * Also change the status of @dev's links to suppliers to "active".
1285 *
1286 * Links without the DL_FLAG_MANAGED flag set are ignored.
1287 */
1288void device_links_driver_bound(struct device *dev)
1289{
1290 struct device_link *link, *ln;
1291 LIST_HEAD(sync_list);
1292
1293 /*
1294 * If a device binds successfully, it's expected to have created all
1295 * the device links it needs to or make new device links as it needs
1296 * them. So, fw_devlink no longer needs to create device links to any
1297 * of the device's suppliers.
1298 *
1299 * Also, if a child firmware node of this bound device is not added as a
1300 * device by now, assume it is never going to be added. Make this bound
1301 * device the fallback supplier to the dangling consumers of the child
1302 * firmware node because this bound device is probably implementing the
1303 * child firmware node functionality and we don't want the dangling
1304 * consumers to defer probe indefinitely waiting for a device for the
1305 * child firmware node.
1306 */
1307 if (dev->fwnode && dev->fwnode->dev == dev) {
1308 struct fwnode_handle *child;
1309 fwnode_links_purge_suppliers(dev->fwnode);
1310 mutex_lock(&fwnode_link_lock);
1311 fwnode_for_each_available_child_node(dev->fwnode, child)
1312 __fw_devlink_pickup_dangling_consumers(child,
1313 dev->fwnode);
1314 __fw_devlink_link_to_consumers(dev);
1315 mutex_unlock(&fwnode_link_lock);
1316 }
1317 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1318
1319 device_links_write_lock();
1320
1321 list_for_each_entry(link, &dev->links.consumers, s_node) {
1322 if (!(link->flags & DL_FLAG_MANAGED))
1323 continue;
1324
1325 /*
1326 * Links created during consumer probe may be in the "consumer
1327 * probe" state to start with if the supplier is still probing
1328 * when they are created and they may become "active" if the
1329 * consumer probe returns first. Skip them here.
1330 */
1331 if (link->status == DL_STATE_CONSUMER_PROBE ||
1332 link->status == DL_STATE_ACTIVE)
1333 continue;
1334
1335 WARN_ON(link->status != DL_STATE_DORMANT);
1336 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1337
1338 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1339 driver_deferred_probe_add(link->consumer);
1340 }
1341
1342 if (defer_sync_state_count)
1343 __device_links_supplier_defer_sync(dev);
1344 else
1345 __device_links_queue_sync_state(dev, &sync_list);
1346
1347 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1348 struct device *supplier;
1349
1350 if (!(link->flags & DL_FLAG_MANAGED))
1351 continue;
1352
1353 supplier = link->supplier;
1354 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1355 /*
1356 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1357 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1358 * save to drop the managed link completely.
1359 */
1360 device_link_drop_managed(link);
1361 } else if (dev_is_best_effort(dev) &&
1362 link->flags & DL_FLAG_INFERRED &&
1363 link->status != DL_STATE_CONSUMER_PROBE &&
1364 !link->supplier->can_match) {
1365 /*
1366 * When dev_is_best_effort() is true, we ignore device
1367 * links to suppliers that don't have a driver. If the
1368 * consumer device still managed to probe, there's no
1369 * point in maintaining a device link in a weird state
1370 * (consumer probed before supplier). So delete it.
1371 */
1372 device_link_drop_managed(link);
1373 } else {
1374 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1375 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1376 }
1377
1378 /*
1379 * This needs to be done even for the deleted
1380 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1381 * device link that was preventing the supplier from getting a
1382 * sync_state() call.
1383 */
1384 if (defer_sync_state_count)
1385 __device_links_supplier_defer_sync(supplier);
1386 else
1387 __device_links_queue_sync_state(supplier, &sync_list);
1388 }
1389
1390 dev->links.status = DL_DEV_DRIVER_BOUND;
1391
1392 device_links_write_unlock();
1393
1394 device_links_flush_sync_list(&sync_list, dev);
1395}
1396
1397/**
1398 * __device_links_no_driver - Update links of a device without a driver.
1399 * @dev: Device without a drvier.
1400 *
1401 * Delete all non-persistent links from this device to any suppliers.
1402 *
1403 * Persistent links stay around, but their status is changed to "available",
1404 * unless they already are in the "supplier unbind in progress" state in which
1405 * case they need not be updated.
1406 *
1407 * Links without the DL_FLAG_MANAGED flag set are ignored.
1408 */
1409static void __device_links_no_driver(struct device *dev)
1410{
1411 struct device_link *link, *ln;
1412
1413 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1414 if (!(link->flags & DL_FLAG_MANAGED))
1415 continue;
1416
1417 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1418 device_link_drop_managed(link);
1419 continue;
1420 }
1421
1422 if (link->status != DL_STATE_CONSUMER_PROBE &&
1423 link->status != DL_STATE_ACTIVE)
1424 continue;
1425
1426 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1427 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1428 } else {
1429 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1430 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1431 }
1432 }
1433
1434 dev->links.status = DL_DEV_NO_DRIVER;
1435}
1436
1437/**
1438 * device_links_no_driver - Update links after failing driver probe.
1439 * @dev: Device whose driver has just failed to probe.
1440 *
1441 * Clean up leftover links to consumers for @dev and invoke
1442 * %__device_links_no_driver() to update links to suppliers for it as
1443 * appropriate.
1444 *
1445 * Links without the DL_FLAG_MANAGED flag set are ignored.
1446 */
1447void device_links_no_driver(struct device *dev)
1448{
1449 struct device_link *link;
1450
1451 device_links_write_lock();
1452
1453 list_for_each_entry(link, &dev->links.consumers, s_node) {
1454 if (!(link->flags & DL_FLAG_MANAGED))
1455 continue;
1456
1457 /*
1458 * The probe has failed, so if the status of the link is
1459 * "consumer probe" or "active", it must have been added by
1460 * a probing consumer while this device was still probing.
1461 * Change its state to "dormant", as it represents a valid
1462 * relationship, but it is not functionally meaningful.
1463 */
1464 if (link->status == DL_STATE_CONSUMER_PROBE ||
1465 link->status == DL_STATE_ACTIVE)
1466 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1467 }
1468
1469 __device_links_no_driver(dev);
1470
1471 device_links_write_unlock();
1472}
1473
1474/**
1475 * device_links_driver_cleanup - Update links after driver removal.
1476 * @dev: Device whose driver has just gone away.
1477 *
1478 * Update links to consumers for @dev by changing their status to "dormant" and
1479 * invoke %__device_links_no_driver() to update links to suppliers for it as
1480 * appropriate.
1481 *
1482 * Links without the DL_FLAG_MANAGED flag set are ignored.
1483 */
1484void device_links_driver_cleanup(struct device *dev)
1485{
1486 struct device_link *link, *ln;
1487
1488 device_links_write_lock();
1489
1490 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1491 if (!(link->flags & DL_FLAG_MANAGED))
1492 continue;
1493
1494 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1495 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1496
1497 /*
1498 * autoremove the links between this @dev and its consumer
1499 * devices that are not active, i.e. where the link state
1500 * has moved to DL_STATE_SUPPLIER_UNBIND.
1501 */
1502 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1503 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1504 device_link_drop_managed(link);
1505
1506 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1507 }
1508
1509 list_del_init(&dev->links.defer_sync);
1510 __device_links_no_driver(dev);
1511
1512 device_links_write_unlock();
1513}
1514
1515/**
1516 * device_links_busy - Check if there are any busy links to consumers.
1517 * @dev: Device to check.
1518 *
1519 * Check each consumer of the device and return 'true' if its link's status
1520 * is one of "consumer probe" or "active" (meaning that the given consumer is
1521 * probing right now or its driver is present). Otherwise, change the link
1522 * state to "supplier unbind" to prevent the consumer from being probed
1523 * successfully going forward.
1524 *
1525 * Return 'false' if there are no probing or active consumers.
1526 *
1527 * Links without the DL_FLAG_MANAGED flag set are ignored.
1528 */
1529bool device_links_busy(struct device *dev)
1530{
1531 struct device_link *link;
1532 bool ret = false;
1533
1534 device_links_write_lock();
1535
1536 list_for_each_entry(link, &dev->links.consumers, s_node) {
1537 if (!(link->flags & DL_FLAG_MANAGED))
1538 continue;
1539
1540 if (link->status == DL_STATE_CONSUMER_PROBE
1541 || link->status == DL_STATE_ACTIVE) {
1542 ret = true;
1543 break;
1544 }
1545 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1546 }
1547
1548 dev->links.status = DL_DEV_UNBINDING;
1549
1550 device_links_write_unlock();
1551 return ret;
1552}
1553
1554/**
1555 * device_links_unbind_consumers - Force unbind consumers of the given device.
1556 * @dev: Device to unbind the consumers of.
1557 *
1558 * Walk the list of links to consumers for @dev and if any of them is in the
1559 * "consumer probe" state, wait for all device probes in progress to complete
1560 * and start over.
1561 *
1562 * If that's not the case, change the status of the link to "supplier unbind"
1563 * and check if the link was in the "active" state. If so, force the consumer
1564 * driver to unbind and start over (the consumer will not re-probe as we have
1565 * changed the state of the link already).
1566 *
1567 * Links without the DL_FLAG_MANAGED flag set are ignored.
1568 */
1569void device_links_unbind_consumers(struct device *dev)
1570{
1571 struct device_link *link;
1572
1573 start:
1574 device_links_write_lock();
1575
1576 list_for_each_entry(link, &dev->links.consumers, s_node) {
1577 enum device_link_state status;
1578
1579 if (!(link->flags & DL_FLAG_MANAGED) ||
1580 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1581 continue;
1582
1583 status = link->status;
1584 if (status == DL_STATE_CONSUMER_PROBE) {
1585 device_links_write_unlock();
1586
1587 wait_for_device_probe();
1588 goto start;
1589 }
1590 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1591 if (status == DL_STATE_ACTIVE) {
1592 struct device *consumer = link->consumer;
1593
1594 get_device(consumer);
1595
1596 device_links_write_unlock();
1597
1598 device_release_driver_internal(consumer, NULL,
1599 consumer->parent);
1600 put_device(consumer);
1601 goto start;
1602 }
1603 }
1604
1605 device_links_write_unlock();
1606}
1607
1608/**
1609 * device_links_purge - Delete existing links to other devices.
1610 * @dev: Target device.
1611 */
1612static void device_links_purge(struct device *dev)
1613{
1614 struct device_link *link, *ln;
1615
1616 if (dev->class == &devlink_class)
1617 return;
1618
1619 /*
1620 * Delete all of the remaining links from this device to any other
1621 * devices (either consumers or suppliers).
1622 */
1623 device_links_write_lock();
1624
1625 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1626 WARN_ON(link->status == DL_STATE_ACTIVE);
1627 __device_link_del(&link->kref);
1628 }
1629
1630 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1631 WARN_ON(link->status != DL_STATE_DORMANT &&
1632 link->status != DL_STATE_NONE);
1633 __device_link_del(&link->kref);
1634 }
1635
1636 device_links_write_unlock();
1637}
1638
1639#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1640 DL_FLAG_SYNC_STATE_ONLY)
1641#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1642 DL_FLAG_AUTOPROBE_CONSUMER)
1643#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1644 DL_FLAG_PM_RUNTIME)
1645
1646static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1647static int __init fw_devlink_setup(char *arg)
1648{
1649 if (!arg)
1650 return -EINVAL;
1651
1652 if (strcmp(arg, "off") == 0) {
1653 fw_devlink_flags = 0;
1654 } else if (strcmp(arg, "permissive") == 0) {
1655 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1656 } else if (strcmp(arg, "on") == 0) {
1657 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1658 } else if (strcmp(arg, "rpm") == 0) {
1659 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1660 }
1661 return 0;
1662}
1663early_param("fw_devlink", fw_devlink_setup);
1664
1665static bool fw_devlink_strict;
1666static int __init fw_devlink_strict_setup(char *arg)
1667{
1668 return kstrtobool(arg, &fw_devlink_strict);
1669}
1670early_param("fw_devlink.strict", fw_devlink_strict_setup);
1671
1672#define FW_DEVLINK_SYNC_STATE_STRICT 0
1673#define FW_DEVLINK_SYNC_STATE_TIMEOUT 1
1674
1675#ifndef CONFIG_FW_DEVLINK_SYNC_STATE_TIMEOUT
1676static int fw_devlink_sync_state;
1677#else
1678static int fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1679#endif
1680
1681static int __init fw_devlink_sync_state_setup(char *arg)
1682{
1683 if (!arg)
1684 return -EINVAL;
1685
1686 if (strcmp(arg, "strict") == 0) {
1687 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_STRICT;
1688 return 0;
1689 } else if (strcmp(arg, "timeout") == 0) {
1690 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1691 return 0;
1692 }
1693 return -EINVAL;
1694}
1695early_param("fw_devlink.sync_state", fw_devlink_sync_state_setup);
1696
1697static inline u32 fw_devlink_get_flags(u8 fwlink_flags)
1698{
1699 if (fwlink_flags & FWLINK_FLAG_CYCLE)
1700 return FW_DEVLINK_FLAGS_PERMISSIVE | DL_FLAG_CYCLE;
1701
1702 return fw_devlink_flags;
1703}
1704
1705static bool fw_devlink_is_permissive(void)
1706{
1707 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1708}
1709
1710bool fw_devlink_is_strict(void)
1711{
1712 return fw_devlink_strict && !fw_devlink_is_permissive();
1713}
1714
1715static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1716{
1717 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1718 return;
1719
1720 fwnode_call_int_op(fwnode, add_links);
1721 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1722}
1723
1724static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1725{
1726 struct fwnode_handle *child = NULL;
1727
1728 fw_devlink_parse_fwnode(fwnode);
1729
1730 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1731 fw_devlink_parse_fwtree(child);
1732}
1733
1734static void fw_devlink_relax_link(struct device_link *link)
1735{
1736 if (!(link->flags & DL_FLAG_INFERRED))
1737 return;
1738
1739 if (device_link_flag_is_sync_state_only(link->flags))
1740 return;
1741
1742 pm_runtime_drop_link(link);
1743 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1744 dev_dbg(link->consumer, "Relaxing link with %s\n",
1745 dev_name(link->supplier));
1746}
1747
1748static int fw_devlink_no_driver(struct device *dev, void *data)
1749{
1750 struct device_link *link = to_devlink(dev);
1751
1752 if (!link->supplier->can_match)
1753 fw_devlink_relax_link(link);
1754
1755 return 0;
1756}
1757
1758void fw_devlink_drivers_done(void)
1759{
1760 fw_devlink_drv_reg_done = true;
1761 device_links_write_lock();
1762 class_for_each_device(&devlink_class, NULL, NULL,
1763 fw_devlink_no_driver);
1764 device_links_write_unlock();
1765}
1766
1767static int fw_devlink_dev_sync_state(struct device *dev, void *data)
1768{
1769 struct device_link *link = to_devlink(dev);
1770 struct device *sup = link->supplier;
1771
1772 if (!(link->flags & DL_FLAG_MANAGED) ||
1773 link->status == DL_STATE_ACTIVE || sup->state_synced ||
1774 !dev_has_sync_state(sup))
1775 return 0;
1776
1777 if (fw_devlink_sync_state == FW_DEVLINK_SYNC_STATE_STRICT) {
1778 dev_warn(sup, "sync_state() pending due to %s\n",
1779 dev_name(link->consumer));
1780 return 0;
1781 }
1782
1783 if (!list_empty(&sup->links.defer_sync))
1784 return 0;
1785
1786 dev_warn(sup, "Timed out. Forcing sync_state()\n");
1787 sup->state_synced = true;
1788 get_device(sup);
1789 list_add_tail(&sup->links.defer_sync, data);
1790
1791 return 0;
1792}
1793
1794void fw_devlink_probing_done(void)
1795{
1796 LIST_HEAD(sync_list);
1797
1798 device_links_write_lock();
1799 class_for_each_device(&devlink_class, NULL, &sync_list,
1800 fw_devlink_dev_sync_state);
1801 device_links_write_unlock();
1802 device_links_flush_sync_list(&sync_list, NULL);
1803}
1804
1805/**
1806 * wait_for_init_devices_probe - Try to probe any device needed for init
1807 *
1808 * Some devices might need to be probed and bound successfully before the kernel
1809 * boot sequence can finish and move on to init/userspace. For example, a
1810 * network interface might need to be bound to be able to mount a NFS rootfs.
1811 *
1812 * With fw_devlink=on by default, some of these devices might be blocked from
1813 * probing because they are waiting on a optional supplier that doesn't have a
1814 * driver. While fw_devlink will eventually identify such devices and unblock
1815 * the probing automatically, it might be too late by the time it unblocks the
1816 * probing of devices. For example, the IP4 autoconfig might timeout before
1817 * fw_devlink unblocks probing of the network interface.
1818 *
1819 * This function is available to temporarily try and probe all devices that have
1820 * a driver even if some of their suppliers haven't been added or don't have
1821 * drivers.
1822 *
1823 * The drivers can then decide which of the suppliers are optional vs mandatory
1824 * and probe the device if possible. By the time this function returns, all such
1825 * "best effort" probes are guaranteed to be completed. If a device successfully
1826 * probes in this mode, we delete all fw_devlink discovered dependencies of that
1827 * device where the supplier hasn't yet probed successfully because they have to
1828 * be optional dependencies.
1829 *
1830 * Any devices that didn't successfully probe go back to being treated as if
1831 * this function was never called.
1832 *
1833 * This also means that some devices that aren't needed for init and could have
1834 * waited for their optional supplier to probe (when the supplier's module is
1835 * loaded later on) would end up probing prematurely with limited functionality.
1836 * So call this function only when boot would fail without it.
1837 */
1838void __init wait_for_init_devices_probe(void)
1839{
1840 if (!fw_devlink_flags || fw_devlink_is_permissive())
1841 return;
1842
1843 /*
1844 * Wait for all ongoing probes to finish so that the "best effort" is
1845 * only applied to devices that can't probe otherwise.
1846 */
1847 wait_for_device_probe();
1848
1849 pr_info("Trying to probe devices needed for running init ...\n");
1850 fw_devlink_best_effort = true;
1851 driver_deferred_probe_trigger();
1852
1853 /*
1854 * Wait for all "best effort" probes to finish before going back to
1855 * normal enforcement.
1856 */
1857 wait_for_device_probe();
1858 fw_devlink_best_effort = false;
1859}
1860
1861static void fw_devlink_unblock_consumers(struct device *dev)
1862{
1863 struct device_link *link;
1864
1865 if (!fw_devlink_flags || fw_devlink_is_permissive())
1866 return;
1867
1868 device_links_write_lock();
1869 list_for_each_entry(link, &dev->links.consumers, s_node)
1870 fw_devlink_relax_link(link);
1871 device_links_write_unlock();
1872}
1873
1874
1875static bool fwnode_init_without_drv(struct fwnode_handle *fwnode)
1876{
1877 struct device *dev;
1878 bool ret;
1879
1880 if (!(fwnode->flags & FWNODE_FLAG_INITIALIZED))
1881 return false;
1882
1883 dev = get_dev_from_fwnode(fwnode);
1884 ret = !dev || dev->links.status == DL_DEV_NO_DRIVER;
1885 put_device(dev);
1886
1887 return ret;
1888}
1889
1890static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
1891{
1892 struct fwnode_handle *parent;
1893
1894 fwnode_for_each_parent_node(fwnode, parent) {
1895 if (fwnode_init_without_drv(parent)) {
1896 fwnode_handle_put(parent);
1897 return true;
1898 }
1899 }
1900
1901 return false;
1902}
1903
1904/**
1905 * __fw_devlink_relax_cycles - Relax and mark dependency cycles.
1906 * @con: Potential consumer device.
1907 * @sup_handle: Potential supplier's fwnode.
1908 *
1909 * Needs to be called with fwnode_lock and device link lock held.
1910 *
1911 * Check if @sup_handle or any of its ancestors or suppliers direct/indirectly
1912 * depend on @con. This function can detect multiple cyles between @sup_handle
1913 * and @con. When such dependency cycles are found, convert all device links
1914 * created solely by fw_devlink into SYNC_STATE_ONLY device links. Also, mark
1915 * all fwnode links in the cycle with FWLINK_FLAG_CYCLE so that when they are
1916 * converted into a device link in the future, they are created as
1917 * SYNC_STATE_ONLY device links. This is the equivalent of doing
1918 * fw_devlink=permissive just between the devices in the cycle. We need to do
1919 * this because, at this point, fw_devlink can't tell which of these
1920 * dependencies is not a real dependency.
1921 *
1922 * Return true if one or more cycles were found. Otherwise, return false.
1923 */
1924static bool __fw_devlink_relax_cycles(struct device *con,
1925 struct fwnode_handle *sup_handle)
1926{
1927 struct device *sup_dev = NULL, *par_dev = NULL;
1928 struct fwnode_link *link;
1929 struct device_link *dev_link;
1930 bool ret = false;
1931
1932 if (!sup_handle)
1933 return false;
1934
1935 /*
1936 * We aren't trying to find all cycles. Just a cycle between con and
1937 * sup_handle.
1938 */
1939 if (sup_handle->flags & FWNODE_FLAG_VISITED)
1940 return false;
1941
1942 sup_handle->flags |= FWNODE_FLAG_VISITED;
1943
1944 sup_dev = get_dev_from_fwnode(sup_handle);
1945
1946 /* Termination condition. */
1947 if (sup_dev == con) {
1948 pr_debug("----- cycle: start -----\n");
1949 ret = true;
1950 goto out;
1951 }
1952
1953 /*
1954 * If sup_dev is bound to a driver and @con hasn't started binding to a
1955 * driver, sup_dev can't be a consumer of @con. So, no need to check
1956 * further.
1957 */
1958 if (sup_dev && sup_dev->links.status == DL_DEV_DRIVER_BOUND &&
1959 con->links.status == DL_DEV_NO_DRIVER) {
1960 ret = false;
1961 goto out;
1962 }
1963
1964 list_for_each_entry(link, &sup_handle->suppliers, c_hook) {
1965 if (__fw_devlink_relax_cycles(con, link->supplier)) {
1966 __fwnode_link_cycle(link);
1967 ret = true;
1968 }
1969 }
1970
1971 /*
1972 * Give priority to device parent over fwnode parent to account for any
1973 * quirks in how fwnodes are converted to devices.
1974 */
1975 if (sup_dev)
1976 par_dev = get_device(sup_dev->parent);
1977 else
1978 par_dev = fwnode_get_next_parent_dev(sup_handle);
1979
1980 if (par_dev && __fw_devlink_relax_cycles(con, par_dev->fwnode)) {
1981 pr_debug("%pfwf: cycle: child of %pfwf\n", sup_handle,
1982 par_dev->fwnode);
1983 ret = true;
1984 }
1985
1986 if (!sup_dev)
1987 goto out;
1988
1989 list_for_each_entry(dev_link, &sup_dev->links.suppliers, c_node) {
1990 /*
1991 * Ignore a SYNC_STATE_ONLY flag only if it wasn't marked as
1992 * such due to a cycle.
1993 */
1994 if (device_link_flag_is_sync_state_only(dev_link->flags) &&
1995 !(dev_link->flags & DL_FLAG_CYCLE))
1996 continue;
1997
1998 if (__fw_devlink_relax_cycles(con,
1999 dev_link->supplier->fwnode)) {
2000 pr_debug("%pfwf: cycle: depends on %pfwf\n", sup_handle,
2001 dev_link->supplier->fwnode);
2002 fw_devlink_relax_link(dev_link);
2003 dev_link->flags |= DL_FLAG_CYCLE;
2004 ret = true;
2005 }
2006 }
2007
2008out:
2009 sup_handle->flags &= ~FWNODE_FLAG_VISITED;
2010 put_device(sup_dev);
2011 put_device(par_dev);
2012 return ret;
2013}
2014
2015/**
2016 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
2017 * @con: consumer device for the device link
2018 * @sup_handle: fwnode handle of supplier
2019 * @link: fwnode link that's being converted to a device link
2020 *
2021 * This function will try to create a device link between the consumer device
2022 * @con and the supplier device represented by @sup_handle.
2023 *
2024 * The supplier has to be provided as a fwnode because incorrect cycles in
2025 * fwnode links can sometimes cause the supplier device to never be created.
2026 * This function detects such cases and returns an error if it cannot create a
2027 * device link from the consumer to a missing supplier.
2028 *
2029 * Returns,
2030 * 0 on successfully creating a device link
2031 * -EINVAL if the device link cannot be created as expected
2032 * -EAGAIN if the device link cannot be created right now, but it may be
2033 * possible to do that in the future
2034 */
2035static int fw_devlink_create_devlink(struct device *con,
2036 struct fwnode_handle *sup_handle,
2037 struct fwnode_link *link)
2038{
2039 struct device *sup_dev;
2040 int ret = 0;
2041 u32 flags;
2042
2043 if (con->fwnode == link->consumer)
2044 flags = fw_devlink_get_flags(link->flags);
2045 else
2046 flags = FW_DEVLINK_FLAGS_PERMISSIVE;
2047
2048 /*
2049 * In some cases, a device P might also be a supplier to its child node
2050 * C. However, this would defer the probe of C until the probe of P
2051 * completes successfully. This is perfectly fine in the device driver
2052 * model. device_add() doesn't guarantee probe completion of the device
2053 * by the time it returns.
2054 *
2055 * However, there are a few drivers that assume C will finish probing
2056 * as soon as it's added and before P finishes probing. So, we provide
2057 * a flag to let fw_devlink know not to delay the probe of C until the
2058 * probe of P completes successfully.
2059 *
2060 * When such a flag is set, we can't create device links where P is the
2061 * supplier of C as that would delay the probe of C.
2062 */
2063 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
2064 fwnode_is_ancestor_of(sup_handle, con->fwnode))
2065 return -EINVAL;
2066
2067 /*
2068 * SYNC_STATE_ONLY device links don't block probing and supports cycles.
2069 * So, one might expect that cycle detection isn't necessary for them.
2070 * However, if the device link was marked as SYNC_STATE_ONLY because
2071 * it's part of a cycle, then we still need to do cycle detection. This
2072 * is because the consumer and supplier might be part of multiple cycles
2073 * and we need to detect all those cycles.
2074 */
2075 if (!device_link_flag_is_sync_state_only(flags) ||
2076 flags & DL_FLAG_CYCLE) {
2077 device_links_write_lock();
2078 if (__fw_devlink_relax_cycles(con, sup_handle)) {
2079 __fwnode_link_cycle(link);
2080 flags = fw_devlink_get_flags(link->flags);
2081 pr_debug("----- cycle: end -----\n");
2082 dev_info(con, "Fixed dependency cycle(s) with %pfwf\n",
2083 sup_handle);
2084 }
2085 device_links_write_unlock();
2086 }
2087
2088 if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE)
2089 sup_dev = fwnode_get_next_parent_dev(sup_handle);
2090 else
2091 sup_dev = get_dev_from_fwnode(sup_handle);
2092
2093 if (sup_dev) {
2094 /*
2095 * If it's one of those drivers that don't actually bind to
2096 * their device using driver core, then don't wait on this
2097 * supplier device indefinitely.
2098 */
2099 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
2100 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
2101 dev_dbg(con,
2102 "Not linking %pfwf - dev might never probe\n",
2103 sup_handle);
2104 ret = -EINVAL;
2105 goto out;
2106 }
2107
2108 if (con != sup_dev && !device_link_add(con, sup_dev, flags)) {
2109 dev_err(con, "Failed to create device link (0x%x) with %s\n",
2110 flags, dev_name(sup_dev));
2111 ret = -EINVAL;
2112 }
2113
2114 goto out;
2115 }
2116
2117 /*
2118 * Supplier or supplier's ancestor already initialized without a struct
2119 * device or being probed by a driver.
2120 */
2121 if (fwnode_init_without_drv(sup_handle) ||
2122 fwnode_ancestor_init_without_drv(sup_handle)) {
2123 dev_dbg(con, "Not linking %pfwf - might never become dev\n",
2124 sup_handle);
2125 return -EINVAL;
2126 }
2127
2128 ret = -EAGAIN;
2129out:
2130 put_device(sup_dev);
2131 return ret;
2132}
2133
2134/**
2135 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
2136 * @dev: Device that needs to be linked to its consumers
2137 *
2138 * This function looks at all the consumer fwnodes of @dev and creates device
2139 * links between the consumer device and @dev (supplier).
2140 *
2141 * If the consumer device has not been added yet, then this function creates a
2142 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
2143 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
2144 * sync_state() callback before the real consumer device gets to be added and
2145 * then probed.
2146 *
2147 * Once device links are created from the real consumer to @dev (supplier), the
2148 * fwnode links are deleted.
2149 */
2150static void __fw_devlink_link_to_consumers(struct device *dev)
2151{
2152 struct fwnode_handle *fwnode = dev->fwnode;
2153 struct fwnode_link *link, *tmp;
2154
2155 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
2156 struct device *con_dev;
2157 bool own_link = true;
2158 int ret;
2159
2160 con_dev = get_dev_from_fwnode(link->consumer);
2161 /*
2162 * If consumer device is not available yet, make a "proxy"
2163 * SYNC_STATE_ONLY link from the consumer's parent device to
2164 * the supplier device. This is necessary to make sure the
2165 * supplier doesn't get a sync_state() callback before the real
2166 * consumer can create a device link to the supplier.
2167 *
2168 * This proxy link step is needed to handle the case where the
2169 * consumer's parent device is added before the supplier.
2170 */
2171 if (!con_dev) {
2172 con_dev = fwnode_get_next_parent_dev(link->consumer);
2173 /*
2174 * However, if the consumer's parent device is also the
2175 * parent of the supplier, don't create a
2176 * consumer-supplier link from the parent to its child
2177 * device. Such a dependency is impossible.
2178 */
2179 if (con_dev &&
2180 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
2181 put_device(con_dev);
2182 con_dev = NULL;
2183 } else {
2184 own_link = false;
2185 }
2186 }
2187
2188 if (!con_dev)
2189 continue;
2190
2191 ret = fw_devlink_create_devlink(con_dev, fwnode, link);
2192 put_device(con_dev);
2193 if (!own_link || ret == -EAGAIN)
2194 continue;
2195
2196 __fwnode_link_del(link);
2197 }
2198}
2199
2200/**
2201 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
2202 * @dev: The consumer device that needs to be linked to its suppliers
2203 * @fwnode: Root of the fwnode tree that is used to create device links
2204 *
2205 * This function looks at all the supplier fwnodes of fwnode tree rooted at
2206 * @fwnode and creates device links between @dev (consumer) and all the
2207 * supplier devices of the entire fwnode tree at @fwnode.
2208 *
2209 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
2210 * and the real suppliers of @dev. Once these device links are created, the
2211 * fwnode links are deleted.
2212 *
2213 * In addition, it also looks at all the suppliers of the entire fwnode tree
2214 * because some of the child devices of @dev that have not been added yet
2215 * (because @dev hasn't probed) might already have their suppliers added to
2216 * driver core. So, this function creates SYNC_STATE_ONLY device links between
2217 * @dev (consumer) and these suppliers to make sure they don't execute their
2218 * sync_state() callbacks before these child devices have a chance to create
2219 * their device links. The fwnode links that correspond to the child devices
2220 * aren't delete because they are needed later to create the device links
2221 * between the real consumer and supplier devices.
2222 */
2223static void __fw_devlink_link_to_suppliers(struct device *dev,
2224 struct fwnode_handle *fwnode)
2225{
2226 bool own_link = (dev->fwnode == fwnode);
2227 struct fwnode_link *link, *tmp;
2228 struct fwnode_handle *child = NULL;
2229
2230 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
2231 int ret;
2232 struct fwnode_handle *sup = link->supplier;
2233
2234 ret = fw_devlink_create_devlink(dev, sup, link);
2235 if (!own_link || ret == -EAGAIN)
2236 continue;
2237
2238 __fwnode_link_del(link);
2239 }
2240
2241 /*
2242 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
2243 * all the descendants. This proxy link step is needed to handle the
2244 * case where the supplier is added before the consumer's parent device
2245 * (@dev).
2246 */
2247 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
2248 __fw_devlink_link_to_suppliers(dev, child);
2249}
2250
2251static void fw_devlink_link_device(struct device *dev)
2252{
2253 struct fwnode_handle *fwnode = dev->fwnode;
2254
2255 if (!fw_devlink_flags)
2256 return;
2257
2258 fw_devlink_parse_fwtree(fwnode);
2259
2260 mutex_lock(&fwnode_link_lock);
2261 __fw_devlink_link_to_consumers(dev);
2262 __fw_devlink_link_to_suppliers(dev, fwnode);
2263 mutex_unlock(&fwnode_link_lock);
2264}
2265
2266/* Device links support end. */
2267
2268int (*platform_notify)(struct device *dev) = NULL;
2269int (*platform_notify_remove)(struct device *dev) = NULL;
2270static struct kobject *dev_kobj;
2271
2272/* /sys/dev/char */
2273static struct kobject *sysfs_dev_char_kobj;
2274
2275/* /sys/dev/block */
2276static struct kobject *sysfs_dev_block_kobj;
2277
2278static DEFINE_MUTEX(device_hotplug_lock);
2279
2280void lock_device_hotplug(void)
2281{
2282 mutex_lock(&device_hotplug_lock);
2283}
2284
2285void unlock_device_hotplug(void)
2286{
2287 mutex_unlock(&device_hotplug_lock);
2288}
2289
2290int lock_device_hotplug_sysfs(void)
2291{
2292 if (mutex_trylock(&device_hotplug_lock))
2293 return 0;
2294
2295 /* Avoid busy looping (5 ms of sleep should do). */
2296 msleep(5);
2297 return restart_syscall();
2298}
2299
2300#ifdef CONFIG_BLOCK
2301static inline int device_is_not_partition(struct device *dev)
2302{
2303 return !(dev->type == &part_type);
2304}
2305#else
2306static inline int device_is_not_partition(struct device *dev)
2307{
2308 return 1;
2309}
2310#endif
2311
2312static void device_platform_notify(struct device *dev)
2313{
2314 acpi_device_notify(dev);
2315
2316 software_node_notify(dev);
2317
2318 if (platform_notify)
2319 platform_notify(dev);
2320}
2321
2322static void device_platform_notify_remove(struct device *dev)
2323{
2324 if (platform_notify_remove)
2325 platform_notify_remove(dev);
2326
2327 software_node_notify_remove(dev);
2328
2329 acpi_device_notify_remove(dev);
2330}
2331
2332/**
2333 * dev_driver_string - Return a device's driver name, if at all possible
2334 * @dev: struct device to get the name of
2335 *
2336 * Will return the device's driver's name if it is bound to a device. If
2337 * the device is not bound to a driver, it will return the name of the bus
2338 * it is attached to. If it is not attached to a bus either, an empty
2339 * string will be returned.
2340 */
2341const char *dev_driver_string(const struct device *dev)
2342{
2343 struct device_driver *drv;
2344
2345 /* dev->driver can change to NULL underneath us because of unbinding,
2346 * so be careful about accessing it. dev->bus and dev->class should
2347 * never change once they are set, so they don't need special care.
2348 */
2349 drv = READ_ONCE(dev->driver);
2350 return drv ? drv->name : dev_bus_name(dev);
2351}
2352EXPORT_SYMBOL(dev_driver_string);
2353
2354#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2355
2356static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2357 char *buf)
2358{
2359 struct device_attribute *dev_attr = to_dev_attr(attr);
2360 struct device *dev = kobj_to_dev(kobj);
2361 ssize_t ret = -EIO;
2362
2363 if (dev_attr->show)
2364 ret = dev_attr->show(dev, dev_attr, buf);
2365 if (ret >= (ssize_t)PAGE_SIZE) {
2366 printk("dev_attr_show: %pS returned bad count\n",
2367 dev_attr->show);
2368 }
2369 return ret;
2370}
2371
2372static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2373 const char *buf, size_t count)
2374{
2375 struct device_attribute *dev_attr = to_dev_attr(attr);
2376 struct device *dev = kobj_to_dev(kobj);
2377 ssize_t ret = -EIO;
2378
2379 if (dev_attr->store)
2380 ret = dev_attr->store(dev, dev_attr, buf, count);
2381 return ret;
2382}
2383
2384static const struct sysfs_ops dev_sysfs_ops = {
2385 .show = dev_attr_show,
2386 .store = dev_attr_store,
2387};
2388
2389#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2390
2391ssize_t device_store_ulong(struct device *dev,
2392 struct device_attribute *attr,
2393 const char *buf, size_t size)
2394{
2395 struct dev_ext_attribute *ea = to_ext_attr(attr);
2396 int ret;
2397 unsigned long new;
2398
2399 ret = kstrtoul(buf, 0, &new);
2400 if (ret)
2401 return ret;
2402 *(unsigned long *)(ea->var) = new;
2403 /* Always return full write size even if we didn't consume all */
2404 return size;
2405}
2406EXPORT_SYMBOL_GPL(device_store_ulong);
2407
2408ssize_t device_show_ulong(struct device *dev,
2409 struct device_attribute *attr,
2410 char *buf)
2411{
2412 struct dev_ext_attribute *ea = to_ext_attr(attr);
2413 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2414}
2415EXPORT_SYMBOL_GPL(device_show_ulong);
2416
2417ssize_t device_store_int(struct device *dev,
2418 struct device_attribute *attr,
2419 const char *buf, size_t size)
2420{
2421 struct dev_ext_attribute *ea = to_ext_attr(attr);
2422 int ret;
2423 long new;
2424
2425 ret = kstrtol(buf, 0, &new);
2426 if (ret)
2427 return ret;
2428
2429 if (new > INT_MAX || new < INT_MIN)
2430 return -EINVAL;
2431 *(int *)(ea->var) = new;
2432 /* Always return full write size even if we didn't consume all */
2433 return size;
2434}
2435EXPORT_SYMBOL_GPL(device_store_int);
2436
2437ssize_t device_show_int(struct device *dev,
2438 struct device_attribute *attr,
2439 char *buf)
2440{
2441 struct dev_ext_attribute *ea = to_ext_attr(attr);
2442
2443 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2444}
2445EXPORT_SYMBOL_GPL(device_show_int);
2446
2447ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2448 const char *buf, size_t size)
2449{
2450 struct dev_ext_attribute *ea = to_ext_attr(attr);
2451
2452 if (kstrtobool(buf, ea->var) < 0)
2453 return -EINVAL;
2454
2455 return size;
2456}
2457EXPORT_SYMBOL_GPL(device_store_bool);
2458
2459ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2460 char *buf)
2461{
2462 struct dev_ext_attribute *ea = to_ext_attr(attr);
2463
2464 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2465}
2466EXPORT_SYMBOL_GPL(device_show_bool);
2467
2468/**
2469 * device_release - free device structure.
2470 * @kobj: device's kobject.
2471 *
2472 * This is called once the reference count for the object
2473 * reaches 0. We forward the call to the device's release
2474 * method, which should handle actually freeing the structure.
2475 */
2476static void device_release(struct kobject *kobj)
2477{
2478 struct device *dev = kobj_to_dev(kobj);
2479 struct device_private *p = dev->p;
2480
2481 /*
2482 * Some platform devices are driven without driver attached
2483 * and managed resources may have been acquired. Make sure
2484 * all resources are released.
2485 *
2486 * Drivers still can add resources into device after device
2487 * is deleted but alive, so release devres here to avoid
2488 * possible memory leak.
2489 */
2490 devres_release_all(dev);
2491
2492 kfree(dev->dma_range_map);
2493
2494 if (dev->release)
2495 dev->release(dev);
2496 else if (dev->type && dev->type->release)
2497 dev->type->release(dev);
2498 else if (dev->class && dev->class->dev_release)
2499 dev->class->dev_release(dev);
2500 else
2501 WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
2502 dev_name(dev));
2503 kfree(p);
2504}
2505
2506static const void *device_namespace(const struct kobject *kobj)
2507{
2508 const struct device *dev = kobj_to_dev(kobj);
2509 const void *ns = NULL;
2510
2511 if (dev->class && dev->class->ns_type)
2512 ns = dev->class->namespace(dev);
2513
2514 return ns;
2515}
2516
2517static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2518{
2519 const struct device *dev = kobj_to_dev(kobj);
2520
2521 if (dev->class && dev->class->get_ownership)
2522 dev->class->get_ownership(dev, uid, gid);
2523}
2524
2525static const struct kobj_type device_ktype = {
2526 .release = device_release,
2527 .sysfs_ops = &dev_sysfs_ops,
2528 .namespace = device_namespace,
2529 .get_ownership = device_get_ownership,
2530};
2531
2532
2533static int dev_uevent_filter(const struct kobject *kobj)
2534{
2535 const struct kobj_type *ktype = get_ktype(kobj);
2536
2537 if (ktype == &device_ktype) {
2538 const struct device *dev = kobj_to_dev(kobj);
2539 if (dev->bus)
2540 return 1;
2541 if (dev->class)
2542 return 1;
2543 }
2544 return 0;
2545}
2546
2547static const char *dev_uevent_name(const struct kobject *kobj)
2548{
2549 const struct device *dev = kobj_to_dev(kobj);
2550
2551 if (dev->bus)
2552 return dev->bus->name;
2553 if (dev->class)
2554 return dev->class->name;
2555 return NULL;
2556}
2557
2558static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
2559{
2560 const struct device *dev = kobj_to_dev(kobj);
2561 int retval = 0;
2562
2563 /* add device node properties if present */
2564 if (MAJOR(dev->devt)) {
2565 const char *tmp;
2566 const char *name;
2567 umode_t mode = 0;
2568 kuid_t uid = GLOBAL_ROOT_UID;
2569 kgid_t gid = GLOBAL_ROOT_GID;
2570
2571 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2572 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2573 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2574 if (name) {
2575 add_uevent_var(env, "DEVNAME=%s", name);
2576 if (mode)
2577 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2578 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2579 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2580 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2581 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2582 kfree(tmp);
2583 }
2584 }
2585
2586 if (dev->type && dev->type->name)
2587 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2588
2589 if (dev->driver)
2590 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2591
2592 /* Add common DT information about the device */
2593 of_device_uevent(dev, env);
2594
2595 /* have the bus specific function add its stuff */
2596 if (dev->bus && dev->bus->uevent) {
2597 retval = dev->bus->uevent(dev, env);
2598 if (retval)
2599 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2600 dev_name(dev), __func__, retval);
2601 }
2602
2603 /* have the class specific function add its stuff */
2604 if (dev->class && dev->class->dev_uevent) {
2605 retval = dev->class->dev_uevent(dev, env);
2606 if (retval)
2607 pr_debug("device: '%s': %s: class uevent() "
2608 "returned %d\n", dev_name(dev),
2609 __func__, retval);
2610 }
2611
2612 /* have the device type specific function add its stuff */
2613 if (dev->type && dev->type->uevent) {
2614 retval = dev->type->uevent(dev, env);
2615 if (retval)
2616 pr_debug("device: '%s': %s: dev_type uevent() "
2617 "returned %d\n", dev_name(dev),
2618 __func__, retval);
2619 }
2620
2621 return retval;
2622}
2623
2624static const struct kset_uevent_ops device_uevent_ops = {
2625 .filter = dev_uevent_filter,
2626 .name = dev_uevent_name,
2627 .uevent = dev_uevent,
2628};
2629
2630static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2631 char *buf)
2632{
2633 struct kobject *top_kobj;
2634 struct kset *kset;
2635 struct kobj_uevent_env *env = NULL;
2636 int i;
2637 int len = 0;
2638 int retval;
2639
2640 /* search the kset, the device belongs to */
2641 top_kobj = &dev->kobj;
2642 while (!top_kobj->kset && top_kobj->parent)
2643 top_kobj = top_kobj->parent;
2644 if (!top_kobj->kset)
2645 goto out;
2646
2647 kset = top_kobj->kset;
2648 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2649 goto out;
2650
2651 /* respect filter */
2652 if (kset->uevent_ops && kset->uevent_ops->filter)
2653 if (!kset->uevent_ops->filter(&dev->kobj))
2654 goto out;
2655
2656 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2657 if (!env)
2658 return -ENOMEM;
2659
2660 /* let the kset specific function add its keys */
2661 retval = kset->uevent_ops->uevent(&dev->kobj, env);
2662 if (retval)
2663 goto out;
2664
2665 /* copy keys to file */
2666 for (i = 0; i < env->envp_idx; i++)
2667 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2668out:
2669 kfree(env);
2670 return len;
2671}
2672
2673static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2674 const char *buf, size_t count)
2675{
2676 int rc;
2677
2678 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2679
2680 if (rc) {
2681 dev_err(dev, "uevent: failed to send synthetic uevent: %d\n", rc);
2682 return rc;
2683 }
2684
2685 return count;
2686}
2687static DEVICE_ATTR_RW(uevent);
2688
2689static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2690 char *buf)
2691{
2692 bool val;
2693
2694 device_lock(dev);
2695 val = !dev->offline;
2696 device_unlock(dev);
2697 return sysfs_emit(buf, "%u\n", val);
2698}
2699
2700static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2701 const char *buf, size_t count)
2702{
2703 bool val;
2704 int ret;
2705
2706 ret = kstrtobool(buf, &val);
2707 if (ret < 0)
2708 return ret;
2709
2710 ret = lock_device_hotplug_sysfs();
2711 if (ret)
2712 return ret;
2713
2714 ret = val ? device_online(dev) : device_offline(dev);
2715 unlock_device_hotplug();
2716 return ret < 0 ? ret : count;
2717}
2718static DEVICE_ATTR_RW(online);
2719
2720static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2721 char *buf)
2722{
2723 const char *loc;
2724
2725 switch (dev->removable) {
2726 case DEVICE_REMOVABLE:
2727 loc = "removable";
2728 break;
2729 case DEVICE_FIXED:
2730 loc = "fixed";
2731 break;
2732 default:
2733 loc = "unknown";
2734 }
2735 return sysfs_emit(buf, "%s\n", loc);
2736}
2737static DEVICE_ATTR_RO(removable);
2738
2739int device_add_groups(struct device *dev, const struct attribute_group **groups)
2740{
2741 return sysfs_create_groups(&dev->kobj, groups);
2742}
2743EXPORT_SYMBOL_GPL(device_add_groups);
2744
2745void device_remove_groups(struct device *dev,
2746 const struct attribute_group **groups)
2747{
2748 sysfs_remove_groups(&dev->kobj, groups);
2749}
2750EXPORT_SYMBOL_GPL(device_remove_groups);
2751
2752union device_attr_group_devres {
2753 const struct attribute_group *group;
2754 const struct attribute_group **groups;
2755};
2756
2757static void devm_attr_group_remove(struct device *dev, void *res)
2758{
2759 union device_attr_group_devres *devres = res;
2760 const struct attribute_group *group = devres->group;
2761
2762 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2763 sysfs_remove_group(&dev->kobj, group);
2764}
2765
2766static void devm_attr_groups_remove(struct device *dev, void *res)
2767{
2768 union device_attr_group_devres *devres = res;
2769 const struct attribute_group **groups = devres->groups;
2770
2771 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2772 sysfs_remove_groups(&dev->kobj, groups);
2773}
2774
2775/**
2776 * devm_device_add_group - given a device, create a managed attribute group
2777 * @dev: The device to create the group for
2778 * @grp: The attribute group to create
2779 *
2780 * This function creates a group for the first time. It will explicitly
2781 * warn and error if any of the attribute files being created already exist.
2782 *
2783 * Returns 0 on success or error code on failure.
2784 */
2785int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2786{
2787 union device_attr_group_devres *devres;
2788 int error;
2789
2790 devres = devres_alloc(devm_attr_group_remove,
2791 sizeof(*devres), GFP_KERNEL);
2792 if (!devres)
2793 return -ENOMEM;
2794
2795 error = sysfs_create_group(&dev->kobj, grp);
2796 if (error) {
2797 devres_free(devres);
2798 return error;
2799 }
2800
2801 devres->group = grp;
2802 devres_add(dev, devres);
2803 return 0;
2804}
2805EXPORT_SYMBOL_GPL(devm_device_add_group);
2806
2807/**
2808 * devm_device_add_groups - create a bunch of managed attribute groups
2809 * @dev: The device to create the group for
2810 * @groups: The attribute groups to create, NULL terminated
2811 *
2812 * This function creates a bunch of managed attribute groups. If an error
2813 * occurs when creating a group, all previously created groups will be
2814 * removed, unwinding everything back to the original state when this
2815 * function was called. It will explicitly warn and error if any of the
2816 * attribute files being created already exist.
2817 *
2818 * Returns 0 on success or error code from sysfs_create_group on failure.
2819 */
2820int devm_device_add_groups(struct device *dev,
2821 const struct attribute_group **groups)
2822{
2823 union device_attr_group_devres *devres;
2824 int error;
2825
2826 devres = devres_alloc(devm_attr_groups_remove,
2827 sizeof(*devres), GFP_KERNEL);
2828 if (!devres)
2829 return -ENOMEM;
2830
2831 error = sysfs_create_groups(&dev->kobj, groups);
2832 if (error) {
2833 devres_free(devres);
2834 return error;
2835 }
2836
2837 devres->groups = groups;
2838 devres_add(dev, devres);
2839 return 0;
2840}
2841EXPORT_SYMBOL_GPL(devm_device_add_groups);
2842
2843static int device_add_attrs(struct device *dev)
2844{
2845 const struct class *class = dev->class;
2846 const struct device_type *type = dev->type;
2847 int error;
2848
2849 if (class) {
2850 error = device_add_groups(dev, class->dev_groups);
2851 if (error)
2852 return error;
2853 }
2854
2855 if (type) {
2856 error = device_add_groups(dev, type->groups);
2857 if (error)
2858 goto err_remove_class_groups;
2859 }
2860
2861 error = device_add_groups(dev, dev->groups);
2862 if (error)
2863 goto err_remove_type_groups;
2864
2865 if (device_supports_offline(dev) && !dev->offline_disabled) {
2866 error = device_create_file(dev, &dev_attr_online);
2867 if (error)
2868 goto err_remove_dev_groups;
2869 }
2870
2871 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2872 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2873 if (error)
2874 goto err_remove_dev_online;
2875 }
2876
2877 if (dev_removable_is_valid(dev)) {
2878 error = device_create_file(dev, &dev_attr_removable);
2879 if (error)
2880 goto err_remove_dev_waiting_for_supplier;
2881 }
2882
2883 if (dev_add_physical_location(dev)) {
2884 error = device_add_group(dev,
2885 &dev_attr_physical_location_group);
2886 if (error)
2887 goto err_remove_dev_removable;
2888 }
2889
2890 return 0;
2891
2892 err_remove_dev_removable:
2893 device_remove_file(dev, &dev_attr_removable);
2894 err_remove_dev_waiting_for_supplier:
2895 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2896 err_remove_dev_online:
2897 device_remove_file(dev, &dev_attr_online);
2898 err_remove_dev_groups:
2899 device_remove_groups(dev, dev->groups);
2900 err_remove_type_groups:
2901 if (type)
2902 device_remove_groups(dev, type->groups);
2903 err_remove_class_groups:
2904 if (class)
2905 device_remove_groups(dev, class->dev_groups);
2906
2907 return error;
2908}
2909
2910static void device_remove_attrs(struct device *dev)
2911{
2912 const struct class *class = dev->class;
2913 const struct device_type *type = dev->type;
2914
2915 if (dev->physical_location) {
2916 device_remove_group(dev, &dev_attr_physical_location_group);
2917 kfree(dev->physical_location);
2918 }
2919
2920 device_remove_file(dev, &dev_attr_removable);
2921 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2922 device_remove_file(dev, &dev_attr_online);
2923 device_remove_groups(dev, dev->groups);
2924
2925 if (type)
2926 device_remove_groups(dev, type->groups);
2927
2928 if (class)
2929 device_remove_groups(dev, class->dev_groups);
2930}
2931
2932static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2933 char *buf)
2934{
2935 return print_dev_t(buf, dev->devt);
2936}
2937static DEVICE_ATTR_RO(dev);
2938
2939/* /sys/devices/ */
2940struct kset *devices_kset;
2941
2942/**
2943 * devices_kset_move_before - Move device in the devices_kset's list.
2944 * @deva: Device to move.
2945 * @devb: Device @deva should come before.
2946 */
2947static void devices_kset_move_before(struct device *deva, struct device *devb)
2948{
2949 if (!devices_kset)
2950 return;
2951 pr_debug("devices_kset: Moving %s before %s\n",
2952 dev_name(deva), dev_name(devb));
2953 spin_lock(&devices_kset->list_lock);
2954 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2955 spin_unlock(&devices_kset->list_lock);
2956}
2957
2958/**
2959 * devices_kset_move_after - Move device in the devices_kset's list.
2960 * @deva: Device to move
2961 * @devb: Device @deva should come after.
2962 */
2963static void devices_kset_move_after(struct device *deva, struct device *devb)
2964{
2965 if (!devices_kset)
2966 return;
2967 pr_debug("devices_kset: Moving %s after %s\n",
2968 dev_name(deva), dev_name(devb));
2969 spin_lock(&devices_kset->list_lock);
2970 list_move(&deva->kobj.entry, &devb->kobj.entry);
2971 spin_unlock(&devices_kset->list_lock);
2972}
2973
2974/**
2975 * devices_kset_move_last - move the device to the end of devices_kset's list.
2976 * @dev: device to move
2977 */
2978void devices_kset_move_last(struct device *dev)
2979{
2980 if (!devices_kset)
2981 return;
2982 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2983 spin_lock(&devices_kset->list_lock);
2984 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2985 spin_unlock(&devices_kset->list_lock);
2986}
2987
2988/**
2989 * device_create_file - create sysfs attribute file for device.
2990 * @dev: device.
2991 * @attr: device attribute descriptor.
2992 */
2993int device_create_file(struct device *dev,
2994 const struct device_attribute *attr)
2995{
2996 int error = 0;
2997
2998 if (dev) {
2999 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
3000 "Attribute %s: write permission without 'store'\n",
3001 attr->attr.name);
3002 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
3003 "Attribute %s: read permission without 'show'\n",
3004 attr->attr.name);
3005 error = sysfs_create_file(&dev->kobj, &attr->attr);
3006 }
3007
3008 return error;
3009}
3010EXPORT_SYMBOL_GPL(device_create_file);
3011
3012/**
3013 * device_remove_file - remove sysfs attribute file.
3014 * @dev: device.
3015 * @attr: device attribute descriptor.
3016 */
3017void device_remove_file(struct device *dev,
3018 const struct device_attribute *attr)
3019{
3020 if (dev)
3021 sysfs_remove_file(&dev->kobj, &attr->attr);
3022}
3023EXPORT_SYMBOL_GPL(device_remove_file);
3024
3025/**
3026 * device_remove_file_self - remove sysfs attribute file from its own method.
3027 * @dev: device.
3028 * @attr: device attribute descriptor.
3029 *
3030 * See kernfs_remove_self() for details.
3031 */
3032bool device_remove_file_self(struct device *dev,
3033 const struct device_attribute *attr)
3034{
3035 if (dev)
3036 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
3037 else
3038 return false;
3039}
3040EXPORT_SYMBOL_GPL(device_remove_file_self);
3041
3042/**
3043 * device_create_bin_file - create sysfs binary attribute file for device.
3044 * @dev: device.
3045 * @attr: device binary attribute descriptor.
3046 */
3047int device_create_bin_file(struct device *dev,
3048 const struct bin_attribute *attr)
3049{
3050 int error = -EINVAL;
3051 if (dev)
3052 error = sysfs_create_bin_file(&dev->kobj, attr);
3053 return error;
3054}
3055EXPORT_SYMBOL_GPL(device_create_bin_file);
3056
3057/**
3058 * device_remove_bin_file - remove sysfs binary attribute file
3059 * @dev: device.
3060 * @attr: device binary attribute descriptor.
3061 */
3062void device_remove_bin_file(struct device *dev,
3063 const struct bin_attribute *attr)
3064{
3065 if (dev)
3066 sysfs_remove_bin_file(&dev->kobj, attr);
3067}
3068EXPORT_SYMBOL_GPL(device_remove_bin_file);
3069
3070static void klist_children_get(struct klist_node *n)
3071{
3072 struct device_private *p = to_device_private_parent(n);
3073 struct device *dev = p->device;
3074
3075 get_device(dev);
3076}
3077
3078static void klist_children_put(struct klist_node *n)
3079{
3080 struct device_private *p = to_device_private_parent(n);
3081 struct device *dev = p->device;
3082
3083 put_device(dev);
3084}
3085
3086/**
3087 * device_initialize - init device structure.
3088 * @dev: device.
3089 *
3090 * This prepares the device for use by other layers by initializing
3091 * its fields.
3092 * It is the first half of device_register(), if called by
3093 * that function, though it can also be called separately, so one
3094 * may use @dev's fields. In particular, get_device()/put_device()
3095 * may be used for reference counting of @dev after calling this
3096 * function.
3097 *
3098 * All fields in @dev must be initialized by the caller to 0, except
3099 * for those explicitly set to some other value. The simplest
3100 * approach is to use kzalloc() to allocate the structure containing
3101 * @dev.
3102 *
3103 * NOTE: Use put_device() to give up your reference instead of freeing
3104 * @dev directly once you have called this function.
3105 */
3106void device_initialize(struct device *dev)
3107{
3108 dev->kobj.kset = devices_kset;
3109 kobject_init(&dev->kobj, &device_ktype);
3110 INIT_LIST_HEAD(&dev->dma_pools);
3111 mutex_init(&dev->mutex);
3112 lockdep_set_novalidate_class(&dev->mutex);
3113 spin_lock_init(&dev->devres_lock);
3114 INIT_LIST_HEAD(&dev->devres_head);
3115 device_pm_init(dev);
3116 set_dev_node(dev, NUMA_NO_NODE);
3117 INIT_LIST_HEAD(&dev->links.consumers);
3118 INIT_LIST_HEAD(&dev->links.suppliers);
3119 INIT_LIST_HEAD(&dev->links.defer_sync);
3120 dev->links.status = DL_DEV_NO_DRIVER;
3121#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
3122 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
3123 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
3124 dev->dma_coherent = dma_default_coherent;
3125#endif
3126 swiotlb_dev_init(dev);
3127}
3128EXPORT_SYMBOL_GPL(device_initialize);
3129
3130struct kobject *virtual_device_parent(struct device *dev)
3131{
3132 static struct kobject *virtual_dir = NULL;
3133
3134 if (!virtual_dir)
3135 virtual_dir = kobject_create_and_add("virtual",
3136 &devices_kset->kobj);
3137
3138 return virtual_dir;
3139}
3140
3141struct class_dir {
3142 struct kobject kobj;
3143 const struct class *class;
3144};
3145
3146#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
3147
3148static void class_dir_release(struct kobject *kobj)
3149{
3150 struct class_dir *dir = to_class_dir(kobj);
3151 kfree(dir);
3152}
3153
3154static const
3155struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *kobj)
3156{
3157 const struct class_dir *dir = to_class_dir(kobj);
3158 return dir->class->ns_type;
3159}
3160
3161static const struct kobj_type class_dir_ktype = {
3162 .release = class_dir_release,
3163 .sysfs_ops = &kobj_sysfs_ops,
3164 .child_ns_type = class_dir_child_ns_type
3165};
3166
3167static struct kobject *class_dir_create_and_add(struct subsys_private *sp,
3168 struct kobject *parent_kobj)
3169{
3170 struct class_dir *dir;
3171 int retval;
3172
3173 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
3174 if (!dir)
3175 return ERR_PTR(-ENOMEM);
3176
3177 dir->class = sp->class;
3178 kobject_init(&dir->kobj, &class_dir_ktype);
3179
3180 dir->kobj.kset = &sp->glue_dirs;
3181
3182 retval = kobject_add(&dir->kobj, parent_kobj, "%s", sp->class->name);
3183 if (retval < 0) {
3184 kobject_put(&dir->kobj);
3185 return ERR_PTR(retval);
3186 }
3187 return &dir->kobj;
3188}
3189
3190static DEFINE_MUTEX(gdp_mutex);
3191
3192static struct kobject *get_device_parent(struct device *dev,
3193 struct device *parent)
3194{
3195 struct subsys_private *sp = class_to_subsys(dev->class);
3196 struct kobject *kobj = NULL;
3197
3198 if (sp) {
3199 struct kobject *parent_kobj;
3200 struct kobject *k;
3201
3202 /*
3203 * If we have no parent, we live in "virtual".
3204 * Class-devices with a non class-device as parent, live
3205 * in a "glue" directory to prevent namespace collisions.
3206 */
3207 if (parent == NULL)
3208 parent_kobj = virtual_device_parent(dev);
3209 else if (parent->class && !dev->class->ns_type) {
3210 subsys_put(sp);
3211 return &parent->kobj;
3212 } else {
3213 parent_kobj = &parent->kobj;
3214 }
3215
3216 mutex_lock(&gdp_mutex);
3217
3218 /* find our class-directory at the parent and reference it */
3219 spin_lock(&sp->glue_dirs.list_lock);
3220 list_for_each_entry(k, &sp->glue_dirs.list, entry)
3221 if (k->parent == parent_kobj) {
3222 kobj = kobject_get(k);
3223 break;
3224 }
3225 spin_unlock(&sp->glue_dirs.list_lock);
3226 if (kobj) {
3227 mutex_unlock(&gdp_mutex);
3228 subsys_put(sp);
3229 return kobj;
3230 }
3231
3232 /* or create a new class-directory at the parent device */
3233 k = class_dir_create_and_add(sp, parent_kobj);
3234 /* do not emit an uevent for this simple "glue" directory */
3235 mutex_unlock(&gdp_mutex);
3236 subsys_put(sp);
3237 return k;
3238 }
3239
3240 /* subsystems can specify a default root directory for their devices */
3241 if (!parent && dev->bus) {
3242 struct device *dev_root = bus_get_dev_root(dev->bus);
3243
3244 if (dev_root) {
3245 kobj = &dev_root->kobj;
3246 put_device(dev_root);
3247 return kobj;
3248 }
3249 }
3250
3251 if (parent)
3252 return &parent->kobj;
3253 return NULL;
3254}
3255
3256static inline bool live_in_glue_dir(struct kobject *kobj,
3257 struct device *dev)
3258{
3259 struct subsys_private *sp;
3260 bool retval;
3261
3262 if (!kobj || !dev->class)
3263 return false;
3264
3265 sp = class_to_subsys(dev->class);
3266 if (!sp)
3267 return false;
3268
3269 if (kobj->kset == &sp->glue_dirs)
3270 retval = true;
3271 else
3272 retval = false;
3273
3274 subsys_put(sp);
3275 return retval;
3276}
3277
3278static inline struct kobject *get_glue_dir(struct device *dev)
3279{
3280 return dev->kobj.parent;
3281}
3282
3283/**
3284 * kobject_has_children - Returns whether a kobject has children.
3285 * @kobj: the object to test
3286 *
3287 * This will return whether a kobject has other kobjects as children.
3288 *
3289 * It does NOT account for the presence of attribute files, only sub
3290 * directories. It also assumes there is no concurrent addition or
3291 * removal of such children, and thus relies on external locking.
3292 */
3293static inline bool kobject_has_children(struct kobject *kobj)
3294{
3295 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
3296
3297 return kobj->sd && kobj->sd->dir.subdirs;
3298}
3299
3300/*
3301 * make sure cleaning up dir as the last step, we need to make
3302 * sure .release handler of kobject is run with holding the
3303 * global lock
3304 */
3305static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3306{
3307 unsigned int ref;
3308
3309 /* see if we live in a "glue" directory */
3310 if (!live_in_glue_dir(glue_dir, dev))
3311 return;
3312
3313 mutex_lock(&gdp_mutex);
3314 /**
3315 * There is a race condition between removing glue directory
3316 * and adding a new device under the glue directory.
3317 *
3318 * CPU1: CPU2:
3319 *
3320 * device_add()
3321 * get_device_parent()
3322 * class_dir_create_and_add()
3323 * kobject_add_internal()
3324 * create_dir() // create glue_dir
3325 *
3326 * device_add()
3327 * get_device_parent()
3328 * kobject_get() // get glue_dir
3329 *
3330 * device_del()
3331 * cleanup_glue_dir()
3332 * kobject_del(glue_dir)
3333 *
3334 * kobject_add()
3335 * kobject_add_internal()
3336 * create_dir() // in glue_dir
3337 * sysfs_create_dir_ns()
3338 * kernfs_create_dir_ns(sd)
3339 *
3340 * sysfs_remove_dir() // glue_dir->sd=NULL
3341 * sysfs_put() // free glue_dir->sd
3342 *
3343 * // sd is freed
3344 * kernfs_new_node(sd)
3345 * kernfs_get(glue_dir)
3346 * kernfs_add_one()
3347 * kernfs_put()
3348 *
3349 * Before CPU1 remove last child device under glue dir, if CPU2 add
3350 * a new device under glue dir, the glue_dir kobject reference count
3351 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3352 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3353 * and sysfs_put(). This result in glue_dir->sd is freed.
3354 *
3355 * Then the CPU2 will see a stale "empty" but still potentially used
3356 * glue dir around in kernfs_new_node().
3357 *
3358 * In order to avoid this happening, we also should make sure that
3359 * kernfs_node for glue_dir is released in CPU1 only when refcount
3360 * for glue_dir kobj is 1.
3361 */
3362 ref = kref_read(&glue_dir->kref);
3363 if (!kobject_has_children(glue_dir) && !--ref)
3364 kobject_del(glue_dir);
3365 kobject_put(glue_dir);
3366 mutex_unlock(&gdp_mutex);
3367}
3368
3369static int device_add_class_symlinks(struct device *dev)
3370{
3371 struct device_node *of_node = dev_of_node(dev);
3372 struct subsys_private *sp;
3373 int error;
3374
3375 if (of_node) {
3376 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3377 if (error)
3378 dev_warn(dev, "Error %d creating of_node link\n",error);
3379 /* An error here doesn't warrant bringing down the device */
3380 }
3381
3382 sp = class_to_subsys(dev->class);
3383 if (!sp)
3384 return 0;
3385
3386 error = sysfs_create_link(&dev->kobj, &sp->subsys.kobj, "subsystem");
3387 if (error)
3388 goto out_devnode;
3389
3390 if (dev->parent && device_is_not_partition(dev)) {
3391 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3392 "device");
3393 if (error)
3394 goto out_subsys;
3395 }
3396
3397 /* link in the class directory pointing to the device */
3398 error = sysfs_create_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3399 if (error)
3400 goto out_device;
3401 goto exit;
3402
3403out_device:
3404 sysfs_remove_link(&dev->kobj, "device");
3405out_subsys:
3406 sysfs_remove_link(&dev->kobj, "subsystem");
3407out_devnode:
3408 sysfs_remove_link(&dev->kobj, "of_node");
3409exit:
3410 subsys_put(sp);
3411 return error;
3412}
3413
3414static void device_remove_class_symlinks(struct device *dev)
3415{
3416 struct subsys_private *sp = class_to_subsys(dev->class);
3417
3418 if (dev_of_node(dev))
3419 sysfs_remove_link(&dev->kobj, "of_node");
3420
3421 if (!sp)
3422 return;
3423
3424 if (dev->parent && device_is_not_partition(dev))
3425 sysfs_remove_link(&dev->kobj, "device");
3426 sysfs_remove_link(&dev->kobj, "subsystem");
3427 sysfs_delete_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3428 subsys_put(sp);
3429}
3430
3431/**
3432 * dev_set_name - set a device name
3433 * @dev: device
3434 * @fmt: format string for the device's name
3435 */
3436int dev_set_name(struct device *dev, const char *fmt, ...)
3437{
3438 va_list vargs;
3439 int err;
3440
3441 va_start(vargs, fmt);
3442 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3443 va_end(vargs);
3444 return err;
3445}
3446EXPORT_SYMBOL_GPL(dev_set_name);
3447
3448/* select a /sys/dev/ directory for the device */
3449static struct kobject *device_to_dev_kobj(struct device *dev)
3450{
3451 if (is_blockdev(dev))
3452 return sysfs_dev_block_kobj;
3453 else
3454 return sysfs_dev_char_kobj;
3455}
3456
3457static int device_create_sys_dev_entry(struct device *dev)
3458{
3459 struct kobject *kobj = device_to_dev_kobj(dev);
3460 int error = 0;
3461 char devt_str[15];
3462
3463 if (kobj) {
3464 format_dev_t(devt_str, dev->devt);
3465 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3466 }
3467
3468 return error;
3469}
3470
3471static void device_remove_sys_dev_entry(struct device *dev)
3472{
3473 struct kobject *kobj = device_to_dev_kobj(dev);
3474 char devt_str[15];
3475
3476 if (kobj) {
3477 format_dev_t(devt_str, dev->devt);
3478 sysfs_remove_link(kobj, devt_str);
3479 }
3480}
3481
3482static int device_private_init(struct device *dev)
3483{
3484 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3485 if (!dev->p)
3486 return -ENOMEM;
3487 dev->p->device = dev;
3488 klist_init(&dev->p->klist_children, klist_children_get,
3489 klist_children_put);
3490 INIT_LIST_HEAD(&dev->p->deferred_probe);
3491 return 0;
3492}
3493
3494/**
3495 * device_add - add device to device hierarchy.
3496 * @dev: device.
3497 *
3498 * This is part 2 of device_register(), though may be called
3499 * separately _iff_ device_initialize() has been called separately.
3500 *
3501 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3502 * to the global and sibling lists for the device, then
3503 * adds it to the other relevant subsystems of the driver model.
3504 *
3505 * Do not call this routine or device_register() more than once for
3506 * any device structure. The driver model core is not designed to work
3507 * with devices that get unregistered and then spring back to life.
3508 * (Among other things, it's very hard to guarantee that all references
3509 * to the previous incarnation of @dev have been dropped.) Allocate
3510 * and register a fresh new struct device instead.
3511 *
3512 * NOTE: _Never_ directly free @dev after calling this function, even
3513 * if it returned an error! Always use put_device() to give up your
3514 * reference instead.
3515 *
3516 * Rule of thumb is: if device_add() succeeds, you should call
3517 * device_del() when you want to get rid of it. If device_add() has
3518 * *not* succeeded, use *only* put_device() to drop the reference
3519 * count.
3520 */
3521int device_add(struct device *dev)
3522{
3523 struct subsys_private *sp;
3524 struct device *parent;
3525 struct kobject *kobj;
3526 struct class_interface *class_intf;
3527 int error = -EINVAL;
3528 struct kobject *glue_dir = NULL;
3529
3530 dev = get_device(dev);
3531 if (!dev)
3532 goto done;
3533
3534 if (!dev->p) {
3535 error = device_private_init(dev);
3536 if (error)
3537 goto done;
3538 }
3539
3540 /*
3541 * for statically allocated devices, which should all be converted
3542 * some day, we need to initialize the name. We prevent reading back
3543 * the name, and force the use of dev_name()
3544 */
3545 if (dev->init_name) {
3546 error = dev_set_name(dev, "%s", dev->init_name);
3547 dev->init_name = NULL;
3548 }
3549
3550 if (dev_name(dev))
3551 error = 0;
3552 /* subsystems can specify simple device enumeration */
3553 else if (dev->bus && dev->bus->dev_name)
3554 error = dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3555 else
3556 error = -EINVAL;
3557 if (error)
3558 goto name_error;
3559
3560 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3561
3562 parent = get_device(dev->parent);
3563 kobj = get_device_parent(dev, parent);
3564 if (IS_ERR(kobj)) {
3565 error = PTR_ERR(kobj);
3566 goto parent_error;
3567 }
3568 if (kobj)
3569 dev->kobj.parent = kobj;
3570
3571 /* use parent numa_node */
3572 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3573 set_dev_node(dev, dev_to_node(parent));
3574
3575 /* first, register with generic layer. */
3576 /* we require the name to be set before, and pass NULL */
3577 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3578 if (error) {
3579 glue_dir = kobj;
3580 goto Error;
3581 }
3582
3583 /* notify platform of device entry */
3584 device_platform_notify(dev);
3585
3586 error = device_create_file(dev, &dev_attr_uevent);
3587 if (error)
3588 goto attrError;
3589
3590 error = device_add_class_symlinks(dev);
3591 if (error)
3592 goto SymlinkError;
3593 error = device_add_attrs(dev);
3594 if (error)
3595 goto AttrsError;
3596 error = bus_add_device(dev);
3597 if (error)
3598 goto BusError;
3599 error = dpm_sysfs_add(dev);
3600 if (error)
3601 goto DPMError;
3602 device_pm_add(dev);
3603
3604 if (MAJOR(dev->devt)) {
3605 error = device_create_file(dev, &dev_attr_dev);
3606 if (error)
3607 goto DevAttrError;
3608
3609 error = device_create_sys_dev_entry(dev);
3610 if (error)
3611 goto SysEntryError;
3612
3613 devtmpfs_create_node(dev);
3614 }
3615
3616 /* Notify clients of device addition. This call must come
3617 * after dpm_sysfs_add() and before kobject_uevent().
3618 */
3619 bus_notify(dev, BUS_NOTIFY_ADD_DEVICE);
3620 kobject_uevent(&dev->kobj, KOBJ_ADD);
3621
3622 /*
3623 * Check if any of the other devices (consumers) have been waiting for
3624 * this device (supplier) to be added so that they can create a device
3625 * link to it.
3626 *
3627 * This needs to happen after device_pm_add() because device_link_add()
3628 * requires the supplier be registered before it's called.
3629 *
3630 * But this also needs to happen before bus_probe_device() to make sure
3631 * waiting consumers can link to it before the driver is bound to the
3632 * device and the driver sync_state callback is called for this device.
3633 */
3634 if (dev->fwnode && !dev->fwnode->dev) {
3635 dev->fwnode->dev = dev;
3636 fw_devlink_link_device(dev);
3637 }
3638
3639 bus_probe_device(dev);
3640
3641 /*
3642 * If all driver registration is done and a newly added device doesn't
3643 * match with any driver, don't block its consumers from probing in
3644 * case the consumer device is able to operate without this supplier.
3645 */
3646 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3647 fw_devlink_unblock_consumers(dev);
3648
3649 if (parent)
3650 klist_add_tail(&dev->p->knode_parent,
3651 &parent->p->klist_children);
3652
3653 sp = class_to_subsys(dev->class);
3654 if (sp) {
3655 mutex_lock(&sp->mutex);
3656 /* tie the class to the device */
3657 klist_add_tail(&dev->p->knode_class, &sp->klist_devices);
3658
3659 /* notify any interfaces that the device is here */
3660 list_for_each_entry(class_intf, &sp->interfaces, node)
3661 if (class_intf->add_dev)
3662 class_intf->add_dev(dev);
3663 mutex_unlock(&sp->mutex);
3664 subsys_put(sp);
3665 }
3666done:
3667 put_device(dev);
3668 return error;
3669 SysEntryError:
3670 if (MAJOR(dev->devt))
3671 device_remove_file(dev, &dev_attr_dev);
3672 DevAttrError:
3673 device_pm_remove(dev);
3674 dpm_sysfs_remove(dev);
3675 DPMError:
3676 dev->driver = NULL;
3677 bus_remove_device(dev);
3678 BusError:
3679 device_remove_attrs(dev);
3680 AttrsError:
3681 device_remove_class_symlinks(dev);
3682 SymlinkError:
3683 device_remove_file(dev, &dev_attr_uevent);
3684 attrError:
3685 device_platform_notify_remove(dev);
3686 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3687 glue_dir = get_glue_dir(dev);
3688 kobject_del(&dev->kobj);
3689 Error:
3690 cleanup_glue_dir(dev, glue_dir);
3691parent_error:
3692 put_device(parent);
3693name_error:
3694 kfree(dev->p);
3695 dev->p = NULL;
3696 goto done;
3697}
3698EXPORT_SYMBOL_GPL(device_add);
3699
3700/**
3701 * device_register - register a device with the system.
3702 * @dev: pointer to the device structure
3703 *
3704 * This happens in two clean steps - initialize the device
3705 * and add it to the system. The two steps can be called
3706 * separately, but this is the easiest and most common.
3707 * I.e. you should only call the two helpers separately if
3708 * have a clearly defined need to use and refcount the device
3709 * before it is added to the hierarchy.
3710 *
3711 * For more information, see the kerneldoc for device_initialize()
3712 * and device_add().
3713 *
3714 * NOTE: _Never_ directly free @dev after calling this function, even
3715 * if it returned an error! Always use put_device() to give up the
3716 * reference initialized in this function instead.
3717 */
3718int device_register(struct device *dev)
3719{
3720 device_initialize(dev);
3721 return device_add(dev);
3722}
3723EXPORT_SYMBOL_GPL(device_register);
3724
3725/**
3726 * get_device - increment reference count for device.
3727 * @dev: device.
3728 *
3729 * This simply forwards the call to kobject_get(), though
3730 * we do take care to provide for the case that we get a NULL
3731 * pointer passed in.
3732 */
3733struct device *get_device(struct device *dev)
3734{
3735 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3736}
3737EXPORT_SYMBOL_GPL(get_device);
3738
3739/**
3740 * put_device - decrement reference count.
3741 * @dev: device in question.
3742 */
3743void put_device(struct device *dev)
3744{
3745 /* might_sleep(); */
3746 if (dev)
3747 kobject_put(&dev->kobj);
3748}
3749EXPORT_SYMBOL_GPL(put_device);
3750
3751bool kill_device(struct device *dev)
3752{
3753 /*
3754 * Require the device lock and set the "dead" flag to guarantee that
3755 * the update behavior is consistent with the other bitfields near
3756 * it and that we cannot have an asynchronous probe routine trying
3757 * to run while we are tearing out the bus/class/sysfs from
3758 * underneath the device.
3759 */
3760 device_lock_assert(dev);
3761
3762 if (dev->p->dead)
3763 return false;
3764 dev->p->dead = true;
3765 return true;
3766}
3767EXPORT_SYMBOL_GPL(kill_device);
3768
3769/**
3770 * device_del - delete device from system.
3771 * @dev: device.
3772 *
3773 * This is the first part of the device unregistration
3774 * sequence. This removes the device from the lists we control
3775 * from here, has it removed from the other driver model
3776 * subsystems it was added to in device_add(), and removes it
3777 * from the kobject hierarchy.
3778 *
3779 * NOTE: this should be called manually _iff_ device_add() was
3780 * also called manually.
3781 */
3782void device_del(struct device *dev)
3783{
3784 struct subsys_private *sp;
3785 struct device *parent = dev->parent;
3786 struct kobject *glue_dir = NULL;
3787 struct class_interface *class_intf;
3788 unsigned int noio_flag;
3789
3790 device_lock(dev);
3791 kill_device(dev);
3792 device_unlock(dev);
3793
3794 if (dev->fwnode && dev->fwnode->dev == dev)
3795 dev->fwnode->dev = NULL;
3796
3797 /* Notify clients of device removal. This call must come
3798 * before dpm_sysfs_remove().
3799 */
3800 noio_flag = memalloc_noio_save();
3801 bus_notify(dev, BUS_NOTIFY_DEL_DEVICE);
3802
3803 dpm_sysfs_remove(dev);
3804 if (parent)
3805 klist_del(&dev->p->knode_parent);
3806 if (MAJOR(dev->devt)) {
3807 devtmpfs_delete_node(dev);
3808 device_remove_sys_dev_entry(dev);
3809 device_remove_file(dev, &dev_attr_dev);
3810 }
3811
3812 sp = class_to_subsys(dev->class);
3813 if (sp) {
3814 device_remove_class_symlinks(dev);
3815
3816 mutex_lock(&sp->mutex);
3817 /* notify any interfaces that the device is now gone */
3818 list_for_each_entry(class_intf, &sp->interfaces, node)
3819 if (class_intf->remove_dev)
3820 class_intf->remove_dev(dev);
3821 /* remove the device from the class list */
3822 klist_del(&dev->p->knode_class);
3823 mutex_unlock(&sp->mutex);
3824 subsys_put(sp);
3825 }
3826 device_remove_file(dev, &dev_attr_uevent);
3827 device_remove_attrs(dev);
3828 bus_remove_device(dev);
3829 device_pm_remove(dev);
3830 driver_deferred_probe_del(dev);
3831 device_platform_notify_remove(dev);
3832 device_links_purge(dev);
3833
3834 /*
3835 * If a device does not have a driver attached, we need to clean
3836 * up any managed resources. We do this in device_release(), but
3837 * it's never called (and we leak the device) if a managed
3838 * resource holds a reference to the device. So release all
3839 * managed resources here, like we do in driver_detach(). We
3840 * still need to do so again in device_release() in case someone
3841 * adds a new resource after this point, though.
3842 */
3843 devres_release_all(dev);
3844
3845 bus_notify(dev, BUS_NOTIFY_REMOVED_DEVICE);
3846 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3847 glue_dir = get_glue_dir(dev);
3848 kobject_del(&dev->kobj);
3849 cleanup_glue_dir(dev, glue_dir);
3850 memalloc_noio_restore(noio_flag);
3851 put_device(parent);
3852}
3853EXPORT_SYMBOL_GPL(device_del);
3854
3855/**
3856 * device_unregister - unregister device from system.
3857 * @dev: device going away.
3858 *
3859 * We do this in two parts, like we do device_register(). First,
3860 * we remove it from all the subsystems with device_del(), then
3861 * we decrement the reference count via put_device(). If that
3862 * is the final reference count, the device will be cleaned up
3863 * via device_release() above. Otherwise, the structure will
3864 * stick around until the final reference to the device is dropped.
3865 */
3866void device_unregister(struct device *dev)
3867{
3868 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3869 device_del(dev);
3870 put_device(dev);
3871}
3872EXPORT_SYMBOL_GPL(device_unregister);
3873
3874static struct device *prev_device(struct klist_iter *i)
3875{
3876 struct klist_node *n = klist_prev(i);
3877 struct device *dev = NULL;
3878 struct device_private *p;
3879
3880 if (n) {
3881 p = to_device_private_parent(n);
3882 dev = p->device;
3883 }
3884 return dev;
3885}
3886
3887static struct device *next_device(struct klist_iter *i)
3888{
3889 struct klist_node *n = klist_next(i);
3890 struct device *dev = NULL;
3891 struct device_private *p;
3892
3893 if (n) {
3894 p = to_device_private_parent(n);
3895 dev = p->device;
3896 }
3897 return dev;
3898}
3899
3900/**
3901 * device_get_devnode - path of device node file
3902 * @dev: device
3903 * @mode: returned file access mode
3904 * @uid: returned file owner
3905 * @gid: returned file group
3906 * @tmp: possibly allocated string
3907 *
3908 * Return the relative path of a possible device node.
3909 * Non-default names may need to allocate a memory to compose
3910 * a name. This memory is returned in tmp and needs to be
3911 * freed by the caller.
3912 */
3913const char *device_get_devnode(const struct device *dev,
3914 umode_t *mode, kuid_t *uid, kgid_t *gid,
3915 const char **tmp)
3916{
3917 char *s;
3918
3919 *tmp = NULL;
3920
3921 /* the device type may provide a specific name */
3922 if (dev->type && dev->type->devnode)
3923 *tmp = dev->type->devnode(dev, mode, uid, gid);
3924 if (*tmp)
3925 return *tmp;
3926
3927 /* the class may provide a specific name */
3928 if (dev->class && dev->class->devnode)
3929 *tmp = dev->class->devnode(dev, mode);
3930 if (*tmp)
3931 return *tmp;
3932
3933 /* return name without allocation, tmp == NULL */
3934 if (strchr(dev_name(dev), '!') == NULL)
3935 return dev_name(dev);
3936
3937 /* replace '!' in the name with '/' */
3938 s = kstrdup_and_replace(dev_name(dev), '!', '/', GFP_KERNEL);
3939 if (!s)
3940 return NULL;
3941 return *tmp = s;
3942}
3943
3944/**
3945 * device_for_each_child - device child iterator.
3946 * @parent: parent struct device.
3947 * @fn: function to be called for each device.
3948 * @data: data for the callback.
3949 *
3950 * Iterate over @parent's child devices, and call @fn for each,
3951 * passing it @data.
3952 *
3953 * We check the return of @fn each time. If it returns anything
3954 * other than 0, we break out and return that value.
3955 */
3956int device_for_each_child(struct device *parent, void *data,
3957 int (*fn)(struct device *dev, void *data))
3958{
3959 struct klist_iter i;
3960 struct device *child;
3961 int error = 0;
3962
3963 if (!parent->p)
3964 return 0;
3965
3966 klist_iter_init(&parent->p->klist_children, &i);
3967 while (!error && (child = next_device(&i)))
3968 error = fn(child, data);
3969 klist_iter_exit(&i);
3970 return error;
3971}
3972EXPORT_SYMBOL_GPL(device_for_each_child);
3973
3974/**
3975 * device_for_each_child_reverse - device child iterator in reversed order.
3976 * @parent: parent struct device.
3977 * @fn: function to be called for each device.
3978 * @data: data for the callback.
3979 *
3980 * Iterate over @parent's child devices, and call @fn for each,
3981 * passing it @data.
3982 *
3983 * We check the return of @fn each time. If it returns anything
3984 * other than 0, we break out and return that value.
3985 */
3986int device_for_each_child_reverse(struct device *parent, void *data,
3987 int (*fn)(struct device *dev, void *data))
3988{
3989 struct klist_iter i;
3990 struct device *child;
3991 int error = 0;
3992
3993 if (!parent->p)
3994 return 0;
3995
3996 klist_iter_init(&parent->p->klist_children, &i);
3997 while ((child = prev_device(&i)) && !error)
3998 error = fn(child, data);
3999 klist_iter_exit(&i);
4000 return error;
4001}
4002EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
4003
4004/**
4005 * device_find_child - device iterator for locating a particular device.
4006 * @parent: parent struct device
4007 * @match: Callback function to check device
4008 * @data: Data to pass to match function
4009 *
4010 * This is similar to the device_for_each_child() function above, but it
4011 * returns a reference to a device that is 'found' for later use, as
4012 * determined by the @match callback.
4013 *
4014 * The callback should return 0 if the device doesn't match and non-zero
4015 * if it does. If the callback returns non-zero and a reference to the
4016 * current device can be obtained, this function will return to the caller
4017 * and not iterate over any more devices.
4018 *
4019 * NOTE: you will need to drop the reference with put_device() after use.
4020 */
4021struct device *device_find_child(struct device *parent, void *data,
4022 int (*match)(struct device *dev, void *data))
4023{
4024 struct klist_iter i;
4025 struct device *child;
4026
4027 if (!parent)
4028 return NULL;
4029
4030 klist_iter_init(&parent->p->klist_children, &i);
4031 while ((child = next_device(&i)))
4032 if (match(child, data) && get_device(child))
4033 break;
4034 klist_iter_exit(&i);
4035 return child;
4036}
4037EXPORT_SYMBOL_GPL(device_find_child);
4038
4039/**
4040 * device_find_child_by_name - device iterator for locating a child device.
4041 * @parent: parent struct device
4042 * @name: name of the child device
4043 *
4044 * This is similar to the device_find_child() function above, but it
4045 * returns a reference to a device that has the name @name.
4046 *
4047 * NOTE: you will need to drop the reference with put_device() after use.
4048 */
4049struct device *device_find_child_by_name(struct device *parent,
4050 const char *name)
4051{
4052 struct klist_iter i;
4053 struct device *child;
4054
4055 if (!parent)
4056 return NULL;
4057
4058 klist_iter_init(&parent->p->klist_children, &i);
4059 while ((child = next_device(&i)))
4060 if (sysfs_streq(dev_name(child), name) && get_device(child))
4061 break;
4062 klist_iter_exit(&i);
4063 return child;
4064}
4065EXPORT_SYMBOL_GPL(device_find_child_by_name);
4066
4067static int match_any(struct device *dev, void *unused)
4068{
4069 return 1;
4070}
4071
4072/**
4073 * device_find_any_child - device iterator for locating a child device, if any.
4074 * @parent: parent struct device
4075 *
4076 * This is similar to the device_find_child() function above, but it
4077 * returns a reference to a child device, if any.
4078 *
4079 * NOTE: you will need to drop the reference with put_device() after use.
4080 */
4081struct device *device_find_any_child(struct device *parent)
4082{
4083 return device_find_child(parent, NULL, match_any);
4084}
4085EXPORT_SYMBOL_GPL(device_find_any_child);
4086
4087int __init devices_init(void)
4088{
4089 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
4090 if (!devices_kset)
4091 return -ENOMEM;
4092 dev_kobj = kobject_create_and_add("dev", NULL);
4093 if (!dev_kobj)
4094 goto dev_kobj_err;
4095 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
4096 if (!sysfs_dev_block_kobj)
4097 goto block_kobj_err;
4098 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
4099 if (!sysfs_dev_char_kobj)
4100 goto char_kobj_err;
4101
4102 return 0;
4103
4104 char_kobj_err:
4105 kobject_put(sysfs_dev_block_kobj);
4106 block_kobj_err:
4107 kobject_put(dev_kobj);
4108 dev_kobj_err:
4109 kset_unregister(devices_kset);
4110 return -ENOMEM;
4111}
4112
4113static int device_check_offline(struct device *dev, void *not_used)
4114{
4115 int ret;
4116
4117 ret = device_for_each_child(dev, NULL, device_check_offline);
4118 if (ret)
4119 return ret;
4120
4121 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
4122}
4123
4124/**
4125 * device_offline - Prepare the device for hot-removal.
4126 * @dev: Device to be put offline.
4127 *
4128 * Execute the device bus type's .offline() callback, if present, to prepare
4129 * the device for a subsequent hot-removal. If that succeeds, the device must
4130 * not be used until either it is removed or its bus type's .online() callback
4131 * is executed.
4132 *
4133 * Call under device_hotplug_lock.
4134 */
4135int device_offline(struct device *dev)
4136{
4137 int ret;
4138
4139 if (dev->offline_disabled)
4140 return -EPERM;
4141
4142 ret = device_for_each_child(dev, NULL, device_check_offline);
4143 if (ret)
4144 return ret;
4145
4146 device_lock(dev);
4147 if (device_supports_offline(dev)) {
4148 if (dev->offline) {
4149 ret = 1;
4150 } else {
4151 ret = dev->bus->offline(dev);
4152 if (!ret) {
4153 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
4154 dev->offline = true;
4155 }
4156 }
4157 }
4158 device_unlock(dev);
4159
4160 return ret;
4161}
4162
4163/**
4164 * device_online - Put the device back online after successful device_offline().
4165 * @dev: Device to be put back online.
4166 *
4167 * If device_offline() has been successfully executed for @dev, but the device
4168 * has not been removed subsequently, execute its bus type's .online() callback
4169 * to indicate that the device can be used again.
4170 *
4171 * Call under device_hotplug_lock.
4172 */
4173int device_online(struct device *dev)
4174{
4175 int ret = 0;
4176
4177 device_lock(dev);
4178 if (device_supports_offline(dev)) {
4179 if (dev->offline) {
4180 ret = dev->bus->online(dev);
4181 if (!ret) {
4182 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
4183 dev->offline = false;
4184 }
4185 } else {
4186 ret = 1;
4187 }
4188 }
4189 device_unlock(dev);
4190
4191 return ret;
4192}
4193
4194struct root_device {
4195 struct device dev;
4196 struct module *owner;
4197};
4198
4199static inline struct root_device *to_root_device(struct device *d)
4200{
4201 return container_of(d, struct root_device, dev);
4202}
4203
4204static void root_device_release(struct device *dev)
4205{
4206 kfree(to_root_device(dev));
4207}
4208
4209/**
4210 * __root_device_register - allocate and register a root device
4211 * @name: root device name
4212 * @owner: owner module of the root device, usually THIS_MODULE
4213 *
4214 * This function allocates a root device and registers it
4215 * using device_register(). In order to free the returned
4216 * device, use root_device_unregister().
4217 *
4218 * Root devices are dummy devices which allow other devices
4219 * to be grouped under /sys/devices. Use this function to
4220 * allocate a root device and then use it as the parent of
4221 * any device which should appear under /sys/devices/{name}
4222 *
4223 * The /sys/devices/{name} directory will also contain a
4224 * 'module' symlink which points to the @owner directory
4225 * in sysfs.
4226 *
4227 * Returns &struct device pointer on success, or ERR_PTR() on error.
4228 *
4229 * Note: You probably want to use root_device_register().
4230 */
4231struct device *__root_device_register(const char *name, struct module *owner)
4232{
4233 struct root_device *root;
4234 int err = -ENOMEM;
4235
4236 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
4237 if (!root)
4238 return ERR_PTR(err);
4239
4240 err = dev_set_name(&root->dev, "%s", name);
4241 if (err) {
4242 kfree(root);
4243 return ERR_PTR(err);
4244 }
4245
4246 root->dev.release = root_device_release;
4247
4248 err = device_register(&root->dev);
4249 if (err) {
4250 put_device(&root->dev);
4251 return ERR_PTR(err);
4252 }
4253
4254#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
4255 if (owner) {
4256 struct module_kobject *mk = &owner->mkobj;
4257
4258 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
4259 if (err) {
4260 device_unregister(&root->dev);
4261 return ERR_PTR(err);
4262 }
4263 root->owner = owner;
4264 }
4265#endif
4266
4267 return &root->dev;
4268}
4269EXPORT_SYMBOL_GPL(__root_device_register);
4270
4271/**
4272 * root_device_unregister - unregister and free a root device
4273 * @dev: device going away
4274 *
4275 * This function unregisters and cleans up a device that was created by
4276 * root_device_register().
4277 */
4278void root_device_unregister(struct device *dev)
4279{
4280 struct root_device *root = to_root_device(dev);
4281
4282 if (root->owner)
4283 sysfs_remove_link(&root->dev.kobj, "module");
4284
4285 device_unregister(dev);
4286}
4287EXPORT_SYMBOL_GPL(root_device_unregister);
4288
4289
4290static void device_create_release(struct device *dev)
4291{
4292 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4293 kfree(dev);
4294}
4295
4296static __printf(6, 0) struct device *
4297device_create_groups_vargs(const struct class *class, struct device *parent,
4298 dev_t devt, void *drvdata,
4299 const struct attribute_group **groups,
4300 const char *fmt, va_list args)
4301{
4302 struct device *dev = NULL;
4303 int retval = -ENODEV;
4304
4305 if (IS_ERR_OR_NULL(class))
4306 goto error;
4307
4308 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4309 if (!dev) {
4310 retval = -ENOMEM;
4311 goto error;
4312 }
4313
4314 device_initialize(dev);
4315 dev->devt = devt;
4316 dev->class = class;
4317 dev->parent = parent;
4318 dev->groups = groups;
4319 dev->release = device_create_release;
4320 dev_set_drvdata(dev, drvdata);
4321
4322 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4323 if (retval)
4324 goto error;
4325
4326 retval = device_add(dev);
4327 if (retval)
4328 goto error;
4329
4330 return dev;
4331
4332error:
4333 put_device(dev);
4334 return ERR_PTR(retval);
4335}
4336
4337/**
4338 * device_create - creates a device and registers it with sysfs
4339 * @class: pointer to the struct class that this device should be registered to
4340 * @parent: pointer to the parent struct device of this new device, if any
4341 * @devt: the dev_t for the char device to be added
4342 * @drvdata: the data to be added to the device for callbacks
4343 * @fmt: string for the device's name
4344 *
4345 * This function can be used by char device classes. A struct device
4346 * will be created in sysfs, registered to the specified class.
4347 *
4348 * A "dev" file will be created, showing the dev_t for the device, if
4349 * the dev_t is not 0,0.
4350 * If a pointer to a parent struct device is passed in, the newly created
4351 * struct device will be a child of that device in sysfs.
4352 * The pointer to the struct device will be returned from the call.
4353 * Any further sysfs files that might be required can be created using this
4354 * pointer.
4355 *
4356 * Returns &struct device pointer on success, or ERR_PTR() on error.
4357 */
4358struct device *device_create(const struct class *class, struct device *parent,
4359 dev_t devt, void *drvdata, const char *fmt, ...)
4360{
4361 va_list vargs;
4362 struct device *dev;
4363
4364 va_start(vargs, fmt);
4365 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4366 fmt, vargs);
4367 va_end(vargs);
4368 return dev;
4369}
4370EXPORT_SYMBOL_GPL(device_create);
4371
4372/**
4373 * device_create_with_groups - creates a device and registers it with sysfs
4374 * @class: pointer to the struct class that this device should be registered to
4375 * @parent: pointer to the parent struct device of this new device, if any
4376 * @devt: the dev_t for the char device to be added
4377 * @drvdata: the data to be added to the device for callbacks
4378 * @groups: NULL-terminated list of attribute groups to be created
4379 * @fmt: string for the device's name
4380 *
4381 * This function can be used by char device classes. A struct device
4382 * will be created in sysfs, registered to the specified class.
4383 * Additional attributes specified in the groups parameter will also
4384 * be created automatically.
4385 *
4386 * A "dev" file will be created, showing the dev_t for the device, if
4387 * the dev_t is not 0,0.
4388 * If a pointer to a parent struct device is passed in, the newly created
4389 * struct device will be a child of that device in sysfs.
4390 * The pointer to the struct device will be returned from the call.
4391 * Any further sysfs files that might be required can be created using this
4392 * pointer.
4393 *
4394 * Returns &struct device pointer on success, or ERR_PTR() on error.
4395 */
4396struct device *device_create_with_groups(const struct class *class,
4397 struct device *parent, dev_t devt,
4398 void *drvdata,
4399 const struct attribute_group **groups,
4400 const char *fmt, ...)
4401{
4402 va_list vargs;
4403 struct device *dev;
4404
4405 va_start(vargs, fmt);
4406 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4407 fmt, vargs);
4408 va_end(vargs);
4409 return dev;
4410}
4411EXPORT_SYMBOL_GPL(device_create_with_groups);
4412
4413/**
4414 * device_destroy - removes a device that was created with device_create()
4415 * @class: pointer to the struct class that this device was registered with
4416 * @devt: the dev_t of the device that was previously registered
4417 *
4418 * This call unregisters and cleans up a device that was created with a
4419 * call to device_create().
4420 */
4421void device_destroy(const struct class *class, dev_t devt)
4422{
4423 struct device *dev;
4424
4425 dev = class_find_device_by_devt(class, devt);
4426 if (dev) {
4427 put_device(dev);
4428 device_unregister(dev);
4429 }
4430}
4431EXPORT_SYMBOL_GPL(device_destroy);
4432
4433/**
4434 * device_rename - renames a device
4435 * @dev: the pointer to the struct device to be renamed
4436 * @new_name: the new name of the device
4437 *
4438 * It is the responsibility of the caller to provide mutual
4439 * exclusion between two different calls of device_rename
4440 * on the same device to ensure that new_name is valid and
4441 * won't conflict with other devices.
4442 *
4443 * Note: given that some subsystems (networking and infiniband) use this
4444 * function, with no immediate plans for this to change, we cannot assume or
4445 * require that this function not be called at all.
4446 *
4447 * However, if you're writing new code, do not call this function. The following
4448 * text from Kay Sievers offers some insight:
4449 *
4450 * Renaming devices is racy at many levels, symlinks and other stuff are not
4451 * replaced atomically, and you get a "move" uevent, but it's not easy to
4452 * connect the event to the old and new device. Device nodes are not renamed at
4453 * all, there isn't even support for that in the kernel now.
4454 *
4455 * In the meantime, during renaming, your target name might be taken by another
4456 * driver, creating conflicts. Or the old name is taken directly after you
4457 * renamed it -- then you get events for the same DEVPATH, before you even see
4458 * the "move" event. It's just a mess, and nothing new should ever rely on
4459 * kernel device renaming. Besides that, it's not even implemented now for
4460 * other things than (driver-core wise very simple) network devices.
4461 *
4462 * Make up a "real" name in the driver before you register anything, or add
4463 * some other attributes for userspace to find the device, or use udev to add
4464 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4465 * don't even want to get into that and try to implement the missing pieces in
4466 * the core. We really have other pieces to fix in the driver core mess. :)
4467 */
4468int device_rename(struct device *dev, const char *new_name)
4469{
4470 struct kobject *kobj = &dev->kobj;
4471 char *old_device_name = NULL;
4472 int error;
4473
4474 dev = get_device(dev);
4475 if (!dev)
4476 return -EINVAL;
4477
4478 dev_dbg(dev, "renaming to %s\n", new_name);
4479
4480 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4481 if (!old_device_name) {
4482 error = -ENOMEM;
4483 goto out;
4484 }
4485
4486 if (dev->class) {
4487 struct subsys_private *sp = class_to_subsys(dev->class);
4488
4489 if (!sp) {
4490 error = -EINVAL;
4491 goto out;
4492 }
4493
4494 error = sysfs_rename_link_ns(&sp->subsys.kobj, kobj, old_device_name,
4495 new_name, kobject_namespace(kobj));
4496 subsys_put(sp);
4497 if (error)
4498 goto out;
4499 }
4500
4501 error = kobject_rename(kobj, new_name);
4502 if (error)
4503 goto out;
4504
4505out:
4506 put_device(dev);
4507
4508 kfree(old_device_name);
4509
4510 return error;
4511}
4512EXPORT_SYMBOL_GPL(device_rename);
4513
4514static int device_move_class_links(struct device *dev,
4515 struct device *old_parent,
4516 struct device *new_parent)
4517{
4518 int error = 0;
4519
4520 if (old_parent)
4521 sysfs_remove_link(&dev->kobj, "device");
4522 if (new_parent)
4523 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4524 "device");
4525 return error;
4526}
4527
4528/**
4529 * device_move - moves a device to a new parent
4530 * @dev: the pointer to the struct device to be moved
4531 * @new_parent: the new parent of the device (can be NULL)
4532 * @dpm_order: how to reorder the dpm_list
4533 */
4534int device_move(struct device *dev, struct device *new_parent,
4535 enum dpm_order dpm_order)
4536{
4537 int error;
4538 struct device *old_parent;
4539 struct kobject *new_parent_kobj;
4540
4541 dev = get_device(dev);
4542 if (!dev)
4543 return -EINVAL;
4544
4545 device_pm_lock();
4546 new_parent = get_device(new_parent);
4547 new_parent_kobj = get_device_parent(dev, new_parent);
4548 if (IS_ERR(new_parent_kobj)) {
4549 error = PTR_ERR(new_parent_kobj);
4550 put_device(new_parent);
4551 goto out;
4552 }
4553
4554 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4555 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4556 error = kobject_move(&dev->kobj, new_parent_kobj);
4557 if (error) {
4558 cleanup_glue_dir(dev, new_parent_kobj);
4559 put_device(new_parent);
4560 goto out;
4561 }
4562 old_parent = dev->parent;
4563 dev->parent = new_parent;
4564 if (old_parent)
4565 klist_remove(&dev->p->knode_parent);
4566 if (new_parent) {
4567 klist_add_tail(&dev->p->knode_parent,
4568 &new_parent->p->klist_children);
4569 set_dev_node(dev, dev_to_node(new_parent));
4570 }
4571
4572 if (dev->class) {
4573 error = device_move_class_links(dev, old_parent, new_parent);
4574 if (error) {
4575 /* We ignore errors on cleanup since we're hosed anyway... */
4576 device_move_class_links(dev, new_parent, old_parent);
4577 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4578 if (new_parent)
4579 klist_remove(&dev->p->knode_parent);
4580 dev->parent = old_parent;
4581 if (old_parent) {
4582 klist_add_tail(&dev->p->knode_parent,
4583 &old_parent->p->klist_children);
4584 set_dev_node(dev, dev_to_node(old_parent));
4585 }
4586 }
4587 cleanup_glue_dir(dev, new_parent_kobj);
4588 put_device(new_parent);
4589 goto out;
4590 }
4591 }
4592 switch (dpm_order) {
4593 case DPM_ORDER_NONE:
4594 break;
4595 case DPM_ORDER_DEV_AFTER_PARENT:
4596 device_pm_move_after(dev, new_parent);
4597 devices_kset_move_after(dev, new_parent);
4598 break;
4599 case DPM_ORDER_PARENT_BEFORE_DEV:
4600 device_pm_move_before(new_parent, dev);
4601 devices_kset_move_before(new_parent, dev);
4602 break;
4603 case DPM_ORDER_DEV_LAST:
4604 device_pm_move_last(dev);
4605 devices_kset_move_last(dev);
4606 break;
4607 }
4608
4609 put_device(old_parent);
4610out:
4611 device_pm_unlock();
4612 put_device(dev);
4613 return error;
4614}
4615EXPORT_SYMBOL_GPL(device_move);
4616
4617static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4618 kgid_t kgid)
4619{
4620 struct kobject *kobj = &dev->kobj;
4621 const struct class *class = dev->class;
4622 const struct device_type *type = dev->type;
4623 int error;
4624
4625 if (class) {
4626 /*
4627 * Change the device groups of the device class for @dev to
4628 * @kuid/@kgid.
4629 */
4630 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4631 kgid);
4632 if (error)
4633 return error;
4634 }
4635
4636 if (type) {
4637 /*
4638 * Change the device groups of the device type for @dev to
4639 * @kuid/@kgid.
4640 */
4641 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4642 kgid);
4643 if (error)
4644 return error;
4645 }
4646
4647 /* Change the device groups of @dev to @kuid/@kgid. */
4648 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4649 if (error)
4650 return error;
4651
4652 if (device_supports_offline(dev) && !dev->offline_disabled) {
4653 /* Change online device attributes of @dev to @kuid/@kgid. */
4654 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4655 kuid, kgid);
4656 if (error)
4657 return error;
4658 }
4659
4660 return 0;
4661}
4662
4663/**
4664 * device_change_owner - change the owner of an existing device.
4665 * @dev: device.
4666 * @kuid: new owner's kuid
4667 * @kgid: new owner's kgid
4668 *
4669 * This changes the owner of @dev and its corresponding sysfs entries to
4670 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4671 * core.
4672 *
4673 * Returns 0 on success or error code on failure.
4674 */
4675int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4676{
4677 int error;
4678 struct kobject *kobj = &dev->kobj;
4679 struct subsys_private *sp;
4680
4681 dev = get_device(dev);
4682 if (!dev)
4683 return -EINVAL;
4684
4685 /*
4686 * Change the kobject and the default attributes and groups of the
4687 * ktype associated with it to @kuid/@kgid.
4688 */
4689 error = sysfs_change_owner(kobj, kuid, kgid);
4690 if (error)
4691 goto out;
4692
4693 /*
4694 * Change the uevent file for @dev to the new owner. The uevent file
4695 * was created in a separate step when @dev got added and we mirror
4696 * that step here.
4697 */
4698 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4699 kgid);
4700 if (error)
4701 goto out;
4702
4703 /*
4704 * Change the device groups, the device groups associated with the
4705 * device class, and the groups associated with the device type of @dev
4706 * to @kuid/@kgid.
4707 */
4708 error = device_attrs_change_owner(dev, kuid, kgid);
4709 if (error)
4710 goto out;
4711
4712 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4713 if (error)
4714 goto out;
4715
4716 /*
4717 * Change the owner of the symlink located in the class directory of
4718 * the device class associated with @dev which points to the actual
4719 * directory entry for @dev to @kuid/@kgid. This ensures that the
4720 * symlink shows the same permissions as its target.
4721 */
4722 sp = class_to_subsys(dev->class);
4723 if (!sp) {
4724 error = -EINVAL;
4725 goto out;
4726 }
4727 error = sysfs_link_change_owner(&sp->subsys.kobj, &dev->kobj, dev_name(dev), kuid, kgid);
4728 subsys_put(sp);
4729
4730out:
4731 put_device(dev);
4732 return error;
4733}
4734EXPORT_SYMBOL_GPL(device_change_owner);
4735
4736/**
4737 * device_shutdown - call ->shutdown() on each device to shutdown.
4738 */
4739void device_shutdown(void)
4740{
4741 struct device *dev, *parent;
4742
4743 wait_for_device_probe();
4744 device_block_probing();
4745
4746 cpufreq_suspend();
4747
4748 spin_lock(&devices_kset->list_lock);
4749 /*
4750 * Walk the devices list backward, shutting down each in turn.
4751 * Beware that device unplug events may also start pulling
4752 * devices offline, even as the system is shutting down.
4753 */
4754 while (!list_empty(&devices_kset->list)) {
4755 dev = list_entry(devices_kset->list.prev, struct device,
4756 kobj.entry);
4757
4758 /*
4759 * hold reference count of device's parent to
4760 * prevent it from being freed because parent's
4761 * lock is to be held
4762 */
4763 parent = get_device(dev->parent);
4764 get_device(dev);
4765 /*
4766 * Make sure the device is off the kset list, in the
4767 * event that dev->*->shutdown() doesn't remove it.
4768 */
4769 list_del_init(&dev->kobj.entry);
4770 spin_unlock(&devices_kset->list_lock);
4771
4772 /* hold lock to avoid race with probe/release */
4773 if (parent)
4774 device_lock(parent);
4775 device_lock(dev);
4776
4777 /* Don't allow any more runtime suspends */
4778 pm_runtime_get_noresume(dev);
4779 pm_runtime_barrier(dev);
4780
4781 if (dev->class && dev->class->shutdown_pre) {
4782 if (initcall_debug)
4783 dev_info(dev, "shutdown_pre\n");
4784 dev->class->shutdown_pre(dev);
4785 }
4786 if (dev->bus && dev->bus->shutdown) {
4787 if (initcall_debug)
4788 dev_info(dev, "shutdown\n");
4789 dev->bus->shutdown(dev);
4790 } else if (dev->driver && dev->driver->shutdown) {
4791 if (initcall_debug)
4792 dev_info(dev, "shutdown\n");
4793 dev->driver->shutdown(dev);
4794 }
4795
4796 device_unlock(dev);
4797 if (parent)
4798 device_unlock(parent);
4799
4800 put_device(dev);
4801 put_device(parent);
4802
4803 spin_lock(&devices_kset->list_lock);
4804 }
4805 spin_unlock(&devices_kset->list_lock);
4806}
4807
4808/*
4809 * Device logging functions
4810 */
4811
4812#ifdef CONFIG_PRINTK
4813static void
4814set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4815{
4816 const char *subsys;
4817
4818 memset(dev_info, 0, sizeof(*dev_info));
4819
4820 if (dev->class)
4821 subsys = dev->class->name;
4822 else if (dev->bus)
4823 subsys = dev->bus->name;
4824 else
4825 return;
4826
4827 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4828
4829 /*
4830 * Add device identifier DEVICE=:
4831 * b12:8 block dev_t
4832 * c127:3 char dev_t
4833 * n8 netdev ifindex
4834 * +sound:card0 subsystem:devname
4835 */
4836 if (MAJOR(dev->devt)) {
4837 char c;
4838
4839 if (strcmp(subsys, "block") == 0)
4840 c = 'b';
4841 else
4842 c = 'c';
4843
4844 snprintf(dev_info->device, sizeof(dev_info->device),
4845 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4846 } else if (strcmp(subsys, "net") == 0) {
4847 struct net_device *net = to_net_dev(dev);
4848
4849 snprintf(dev_info->device, sizeof(dev_info->device),
4850 "n%u", net->ifindex);
4851 } else {
4852 snprintf(dev_info->device, sizeof(dev_info->device),
4853 "+%s:%s", subsys, dev_name(dev));
4854 }
4855}
4856
4857int dev_vprintk_emit(int level, const struct device *dev,
4858 const char *fmt, va_list args)
4859{
4860 struct dev_printk_info dev_info;
4861
4862 set_dev_info(dev, &dev_info);
4863
4864 return vprintk_emit(0, level, &dev_info, fmt, args);
4865}
4866EXPORT_SYMBOL(dev_vprintk_emit);
4867
4868int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4869{
4870 va_list args;
4871 int r;
4872
4873 va_start(args, fmt);
4874
4875 r = dev_vprintk_emit(level, dev, fmt, args);
4876
4877 va_end(args);
4878
4879 return r;
4880}
4881EXPORT_SYMBOL(dev_printk_emit);
4882
4883static void __dev_printk(const char *level, const struct device *dev,
4884 struct va_format *vaf)
4885{
4886 if (dev)
4887 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4888 dev_driver_string(dev), dev_name(dev), vaf);
4889 else
4890 printk("%s(NULL device *): %pV", level, vaf);
4891}
4892
4893void _dev_printk(const char *level, const struct device *dev,
4894 const char *fmt, ...)
4895{
4896 struct va_format vaf;
4897 va_list args;
4898
4899 va_start(args, fmt);
4900
4901 vaf.fmt = fmt;
4902 vaf.va = &args;
4903
4904 __dev_printk(level, dev, &vaf);
4905
4906 va_end(args);
4907}
4908EXPORT_SYMBOL(_dev_printk);
4909
4910#define define_dev_printk_level(func, kern_level) \
4911void func(const struct device *dev, const char *fmt, ...) \
4912{ \
4913 struct va_format vaf; \
4914 va_list args; \
4915 \
4916 va_start(args, fmt); \
4917 \
4918 vaf.fmt = fmt; \
4919 vaf.va = &args; \
4920 \
4921 __dev_printk(kern_level, dev, &vaf); \
4922 \
4923 va_end(args); \
4924} \
4925EXPORT_SYMBOL(func);
4926
4927define_dev_printk_level(_dev_emerg, KERN_EMERG);
4928define_dev_printk_level(_dev_alert, KERN_ALERT);
4929define_dev_printk_level(_dev_crit, KERN_CRIT);
4930define_dev_printk_level(_dev_err, KERN_ERR);
4931define_dev_printk_level(_dev_warn, KERN_WARNING);
4932define_dev_printk_level(_dev_notice, KERN_NOTICE);
4933define_dev_printk_level(_dev_info, KERN_INFO);
4934
4935#endif
4936
4937/**
4938 * dev_err_probe - probe error check and log helper
4939 * @dev: the pointer to the struct device
4940 * @err: error value to test
4941 * @fmt: printf-style format string
4942 * @...: arguments as specified in the format string
4943 *
4944 * This helper implements common pattern present in probe functions for error
4945 * checking: print debug or error message depending if the error value is
4946 * -EPROBE_DEFER and propagate error upwards.
4947 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4948 * checked later by reading devices_deferred debugfs attribute.
4949 * It replaces code sequence::
4950 *
4951 * if (err != -EPROBE_DEFER)
4952 * dev_err(dev, ...);
4953 * else
4954 * dev_dbg(dev, ...);
4955 * return err;
4956 *
4957 * with::
4958 *
4959 * return dev_err_probe(dev, err, ...);
4960 *
4961 * Using this helper in your probe function is totally fine even if @err is
4962 * known to never be -EPROBE_DEFER.
4963 * The benefit compared to a normal dev_err() is the standardized format
4964 * of the error code, it being emitted symbolically (i.e. you get "EAGAIN"
4965 * instead of "-35") and the fact that the error code is returned which allows
4966 * more compact error paths.
4967 *
4968 * Returns @err.
4969 */
4970int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4971{
4972 struct va_format vaf;
4973 va_list args;
4974
4975 va_start(args, fmt);
4976 vaf.fmt = fmt;
4977 vaf.va = &args;
4978
4979 if (err != -EPROBE_DEFER) {
4980 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4981 } else {
4982 device_set_deferred_probe_reason(dev, &vaf);
4983 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4984 }
4985
4986 va_end(args);
4987
4988 return err;
4989}
4990EXPORT_SYMBOL_GPL(dev_err_probe);
4991
4992static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4993{
4994 return fwnode && !IS_ERR(fwnode->secondary);
4995}
4996
4997/**
4998 * set_primary_fwnode - Change the primary firmware node of a given device.
4999 * @dev: Device to handle.
5000 * @fwnode: New primary firmware node of the device.
5001 *
5002 * Set the device's firmware node pointer to @fwnode, but if a secondary
5003 * firmware node of the device is present, preserve it.
5004 *
5005 * Valid fwnode cases are:
5006 * - primary --> secondary --> -ENODEV
5007 * - primary --> NULL
5008 * - secondary --> -ENODEV
5009 * - NULL
5010 */
5011void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5012{
5013 struct device *parent = dev->parent;
5014 struct fwnode_handle *fn = dev->fwnode;
5015
5016 if (fwnode) {
5017 if (fwnode_is_primary(fn))
5018 fn = fn->secondary;
5019
5020 if (fn) {
5021 WARN_ON(fwnode->secondary);
5022 fwnode->secondary = fn;
5023 }
5024 dev->fwnode = fwnode;
5025 } else {
5026 if (fwnode_is_primary(fn)) {
5027 dev->fwnode = fn->secondary;
5028
5029 /* Skip nullifying fn->secondary if the primary is shared */
5030 if (parent && fn == parent->fwnode)
5031 return;
5032
5033 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
5034 fn->secondary = NULL;
5035 } else {
5036 dev->fwnode = NULL;
5037 }
5038 }
5039}
5040EXPORT_SYMBOL_GPL(set_primary_fwnode);
5041
5042/**
5043 * set_secondary_fwnode - Change the secondary firmware node of a given device.
5044 * @dev: Device to handle.
5045 * @fwnode: New secondary firmware node of the device.
5046 *
5047 * If a primary firmware node of the device is present, set its secondary
5048 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
5049 * @fwnode.
5050 */
5051void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5052{
5053 if (fwnode)
5054 fwnode->secondary = ERR_PTR(-ENODEV);
5055
5056 if (fwnode_is_primary(dev->fwnode))
5057 dev->fwnode->secondary = fwnode;
5058 else
5059 dev->fwnode = fwnode;
5060}
5061EXPORT_SYMBOL_GPL(set_secondary_fwnode);
5062
5063/**
5064 * device_set_of_node_from_dev - reuse device-tree node of another device
5065 * @dev: device whose device-tree node is being set
5066 * @dev2: device whose device-tree node is being reused
5067 *
5068 * Takes another reference to the new device-tree node after first dropping
5069 * any reference held to the old node.
5070 */
5071void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
5072{
5073 of_node_put(dev->of_node);
5074 dev->of_node = of_node_get(dev2->of_node);
5075 dev->of_node_reused = true;
5076}
5077EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
5078
5079void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
5080{
5081 dev->fwnode = fwnode;
5082 dev->of_node = to_of_node(fwnode);
5083}
5084EXPORT_SYMBOL_GPL(device_set_node);
5085
5086int device_match_name(struct device *dev, const void *name)
5087{
5088 return sysfs_streq(dev_name(dev), name);
5089}
5090EXPORT_SYMBOL_GPL(device_match_name);
5091
5092int device_match_of_node(struct device *dev, const void *np)
5093{
5094 return dev->of_node == np;
5095}
5096EXPORT_SYMBOL_GPL(device_match_of_node);
5097
5098int device_match_fwnode(struct device *dev, const void *fwnode)
5099{
5100 return dev_fwnode(dev) == fwnode;
5101}
5102EXPORT_SYMBOL_GPL(device_match_fwnode);
5103
5104int device_match_devt(struct device *dev, const void *pdevt)
5105{
5106 return dev->devt == *(dev_t *)pdevt;
5107}
5108EXPORT_SYMBOL_GPL(device_match_devt);
5109
5110int device_match_acpi_dev(struct device *dev, const void *adev)
5111{
5112 return ACPI_COMPANION(dev) == adev;
5113}
5114EXPORT_SYMBOL(device_match_acpi_dev);
5115
5116int device_match_acpi_handle(struct device *dev, const void *handle)
5117{
5118 return ACPI_HANDLE(dev) == handle;
5119}
5120EXPORT_SYMBOL(device_match_acpi_handle);
5121
5122int device_match_any(struct device *dev, const void *unused)
5123{
5124 return 1;
5125}
5126EXPORT_SYMBOL_GPL(device_match_any);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/core.c - core driver model code (device registration, etc)
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (c) 2006 Novell, Inc.
9 */
10
11#include <linux/acpi.h>
12#include <linux/blkdev.h>
13#include <linux/cleanup.h>
14#include <linux/cpufreq.h>
15#include <linux/device.h>
16#include <linux/dma-map-ops.h> /* for dma_default_coherent */
17#include <linux/err.h>
18#include <linux/fwnode.h>
19#include <linux/init.h>
20#include <linux/kdev_t.h>
21#include <linux/kstrtox.h>
22#include <linux/module.h>
23#include <linux/mutex.h>
24#include <linux/netdevice.h>
25#include <linux/notifier.h>
26#include <linux/of.h>
27#include <linux/of_device.h>
28#include <linux/pm_runtime.h>
29#include <linux/sched/mm.h>
30#include <linux/sched/signal.h>
31#include <linux/slab.h>
32#include <linux/string_helpers.h>
33#include <linux/swiotlb.h>
34#include <linux/sysfs.h>
35
36#include "base.h"
37#include "physical_location.h"
38#include "power/power.h"
39
40/* Device links support. */
41static LIST_HEAD(deferred_sync);
42static unsigned int defer_sync_state_count = 1;
43static DEFINE_MUTEX(fwnode_link_lock);
44static bool fw_devlink_is_permissive(void);
45static void __fw_devlink_link_to_consumers(struct device *dev);
46static bool fw_devlink_drv_reg_done;
47static bool fw_devlink_best_effort;
48static struct workqueue_struct *device_link_wq;
49
50/**
51 * __fwnode_link_add - Create a link between two fwnode_handles.
52 * @con: Consumer end of the link.
53 * @sup: Supplier end of the link.
54 * @flags: Link flags.
55 *
56 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
57 * represents the detail that the firmware lists @sup fwnode as supplying a
58 * resource to @con.
59 *
60 * The driver core will use the fwnode link to create a device link between the
61 * two device objects corresponding to @con and @sup when they are created. The
62 * driver core will automatically delete the fwnode link between @con and @sup
63 * after doing that.
64 *
65 * Attempts to create duplicate links between the same pair of fwnode handles
66 * are ignored and there is no reference counting.
67 */
68static int __fwnode_link_add(struct fwnode_handle *con,
69 struct fwnode_handle *sup, u8 flags)
70{
71 struct fwnode_link *link;
72
73 list_for_each_entry(link, &sup->consumers, s_hook)
74 if (link->consumer == con) {
75 link->flags |= flags;
76 return 0;
77 }
78
79 link = kzalloc(sizeof(*link), GFP_KERNEL);
80 if (!link)
81 return -ENOMEM;
82
83 link->supplier = sup;
84 INIT_LIST_HEAD(&link->s_hook);
85 link->consumer = con;
86 INIT_LIST_HEAD(&link->c_hook);
87 link->flags = flags;
88
89 list_add(&link->s_hook, &sup->consumers);
90 list_add(&link->c_hook, &con->suppliers);
91 pr_debug("%pfwf Linked as a fwnode consumer to %pfwf\n",
92 con, sup);
93
94 return 0;
95}
96
97int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup,
98 u8 flags)
99{
100 guard(mutex)(&fwnode_link_lock);
101
102 return __fwnode_link_add(con, sup, flags);
103}
104
105/**
106 * __fwnode_link_del - Delete a link between two fwnode_handles.
107 * @link: the fwnode_link to be deleted
108 *
109 * The fwnode_link_lock needs to be held when this function is called.
110 */
111static void __fwnode_link_del(struct fwnode_link *link)
112{
113 pr_debug("%pfwf Dropping the fwnode link to %pfwf\n",
114 link->consumer, link->supplier);
115 list_del(&link->s_hook);
116 list_del(&link->c_hook);
117 kfree(link);
118}
119
120/**
121 * __fwnode_link_cycle - Mark a fwnode link as being part of a cycle.
122 * @link: the fwnode_link to be marked
123 *
124 * The fwnode_link_lock needs to be held when this function is called.
125 */
126static void __fwnode_link_cycle(struct fwnode_link *link)
127{
128 pr_debug("%pfwf: cycle: depends on %pfwf\n",
129 link->consumer, link->supplier);
130 link->flags |= FWLINK_FLAG_CYCLE;
131}
132
133/**
134 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
135 * @fwnode: fwnode whose supplier links need to be deleted
136 *
137 * Deletes all supplier links connecting directly to @fwnode.
138 */
139static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
140{
141 struct fwnode_link *link, *tmp;
142
143 guard(mutex)(&fwnode_link_lock);
144
145 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
146 __fwnode_link_del(link);
147}
148
149/**
150 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
151 * @fwnode: fwnode whose consumer links need to be deleted
152 *
153 * Deletes all consumer links connecting directly to @fwnode.
154 */
155static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
156{
157 struct fwnode_link *link, *tmp;
158
159 guard(mutex)(&fwnode_link_lock);
160
161 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
162 __fwnode_link_del(link);
163}
164
165/**
166 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
167 * @fwnode: fwnode whose links needs to be deleted
168 *
169 * Deletes all links connecting directly to a fwnode.
170 */
171void fwnode_links_purge(struct fwnode_handle *fwnode)
172{
173 fwnode_links_purge_suppliers(fwnode);
174 fwnode_links_purge_consumers(fwnode);
175}
176
177void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
178{
179 struct fwnode_handle *child;
180
181 /* Don't purge consumer links of an added child */
182 if (fwnode->dev)
183 return;
184
185 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
186 fwnode_links_purge_consumers(fwnode);
187
188 fwnode_for_each_available_child_node(fwnode, child)
189 fw_devlink_purge_absent_suppliers(child);
190}
191EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
192
193/**
194 * __fwnode_links_move_consumers - Move consumer from @from to @to fwnode_handle
195 * @from: move consumers away from this fwnode
196 * @to: move consumers to this fwnode
197 *
198 * Move all consumer links from @from fwnode to @to fwnode.
199 */
200static void __fwnode_links_move_consumers(struct fwnode_handle *from,
201 struct fwnode_handle *to)
202{
203 struct fwnode_link *link, *tmp;
204
205 list_for_each_entry_safe(link, tmp, &from->consumers, s_hook) {
206 __fwnode_link_add(link->consumer, to, link->flags);
207 __fwnode_link_del(link);
208 }
209}
210
211/**
212 * __fw_devlink_pickup_dangling_consumers - Pick up dangling consumers
213 * @fwnode: fwnode from which to pick up dangling consumers
214 * @new_sup: fwnode of new supplier
215 *
216 * If the @fwnode has a corresponding struct device and the device supports
217 * probing (that is, added to a bus), then we want to let fw_devlink create
218 * MANAGED device links to this device, so leave @fwnode and its descendant's
219 * fwnode links alone.
220 *
221 * Otherwise, move its consumers to the new supplier @new_sup.
222 */
223static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode,
224 struct fwnode_handle *new_sup)
225{
226 struct fwnode_handle *child;
227
228 if (fwnode->dev && fwnode->dev->bus)
229 return;
230
231 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
232 __fwnode_links_move_consumers(fwnode, new_sup);
233
234 fwnode_for_each_available_child_node(fwnode, child)
235 __fw_devlink_pickup_dangling_consumers(child, new_sup);
236}
237
238static DEFINE_MUTEX(device_links_lock);
239DEFINE_STATIC_SRCU(device_links_srcu);
240
241static inline void device_links_write_lock(void)
242{
243 mutex_lock(&device_links_lock);
244}
245
246static inline void device_links_write_unlock(void)
247{
248 mutex_unlock(&device_links_lock);
249}
250
251int device_links_read_lock(void) __acquires(&device_links_srcu)
252{
253 return srcu_read_lock(&device_links_srcu);
254}
255
256void device_links_read_unlock(int idx) __releases(&device_links_srcu)
257{
258 srcu_read_unlock(&device_links_srcu, idx);
259}
260
261int device_links_read_lock_held(void)
262{
263 return srcu_read_lock_held(&device_links_srcu);
264}
265
266static void device_link_synchronize_removal(void)
267{
268 synchronize_srcu(&device_links_srcu);
269}
270
271static void device_link_remove_from_lists(struct device_link *link)
272{
273 list_del_rcu(&link->s_node);
274 list_del_rcu(&link->c_node);
275}
276
277static bool device_is_ancestor(struct device *dev, struct device *target)
278{
279 while (target->parent) {
280 target = target->parent;
281 if (dev == target)
282 return true;
283 }
284 return false;
285}
286
287#define DL_MARKER_FLAGS (DL_FLAG_INFERRED | \
288 DL_FLAG_CYCLE | \
289 DL_FLAG_MANAGED)
290static inline bool device_link_flag_is_sync_state_only(u32 flags)
291{
292 return (flags & ~DL_MARKER_FLAGS) == DL_FLAG_SYNC_STATE_ONLY;
293}
294
295/**
296 * device_is_dependent - Check if one device depends on another one
297 * @dev: Device to check dependencies for.
298 * @target: Device to check against.
299 *
300 * Check if @target depends on @dev or any device dependent on it (its child or
301 * its consumer etc). Return 1 if that is the case or 0 otherwise.
302 */
303static int device_is_dependent(struct device *dev, void *target)
304{
305 struct device_link *link;
306 int ret;
307
308 /*
309 * The "ancestors" check is needed to catch the case when the target
310 * device has not been completely initialized yet and it is still
311 * missing from the list of children of its parent device.
312 */
313 if (dev == target || device_is_ancestor(dev, target))
314 return 1;
315
316 ret = device_for_each_child(dev, target, device_is_dependent);
317 if (ret)
318 return ret;
319
320 list_for_each_entry(link, &dev->links.consumers, s_node) {
321 if (device_link_flag_is_sync_state_only(link->flags))
322 continue;
323
324 if (link->consumer == target)
325 return 1;
326
327 ret = device_is_dependent(link->consumer, target);
328 if (ret)
329 break;
330 }
331 return ret;
332}
333
334static void device_link_init_status(struct device_link *link,
335 struct device *consumer,
336 struct device *supplier)
337{
338 switch (supplier->links.status) {
339 case DL_DEV_PROBING:
340 switch (consumer->links.status) {
341 case DL_DEV_PROBING:
342 /*
343 * A consumer driver can create a link to a supplier
344 * that has not completed its probing yet as long as it
345 * knows that the supplier is already functional (for
346 * example, it has just acquired some resources from the
347 * supplier).
348 */
349 link->status = DL_STATE_CONSUMER_PROBE;
350 break;
351 default:
352 link->status = DL_STATE_DORMANT;
353 break;
354 }
355 break;
356 case DL_DEV_DRIVER_BOUND:
357 switch (consumer->links.status) {
358 case DL_DEV_PROBING:
359 link->status = DL_STATE_CONSUMER_PROBE;
360 break;
361 case DL_DEV_DRIVER_BOUND:
362 link->status = DL_STATE_ACTIVE;
363 break;
364 default:
365 link->status = DL_STATE_AVAILABLE;
366 break;
367 }
368 break;
369 case DL_DEV_UNBINDING:
370 link->status = DL_STATE_SUPPLIER_UNBIND;
371 break;
372 default:
373 link->status = DL_STATE_DORMANT;
374 break;
375 }
376}
377
378static int device_reorder_to_tail(struct device *dev, void *not_used)
379{
380 struct device_link *link;
381
382 /*
383 * Devices that have not been registered yet will be put to the ends
384 * of the lists during the registration, so skip them here.
385 */
386 if (device_is_registered(dev))
387 devices_kset_move_last(dev);
388
389 if (device_pm_initialized(dev))
390 device_pm_move_last(dev);
391
392 device_for_each_child(dev, NULL, device_reorder_to_tail);
393 list_for_each_entry(link, &dev->links.consumers, s_node) {
394 if (device_link_flag_is_sync_state_only(link->flags))
395 continue;
396 device_reorder_to_tail(link->consumer, NULL);
397 }
398
399 return 0;
400}
401
402/**
403 * device_pm_move_to_tail - Move set of devices to the end of device lists
404 * @dev: Device to move
405 *
406 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
407 *
408 * It moves the @dev along with all of its children and all of its consumers
409 * to the ends of the device_kset and dpm_list, recursively.
410 */
411void device_pm_move_to_tail(struct device *dev)
412{
413 int idx;
414
415 idx = device_links_read_lock();
416 device_pm_lock();
417 device_reorder_to_tail(dev, NULL);
418 device_pm_unlock();
419 device_links_read_unlock(idx);
420}
421
422#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
423
424static ssize_t status_show(struct device *dev,
425 struct device_attribute *attr, char *buf)
426{
427 const char *output;
428
429 switch (to_devlink(dev)->status) {
430 case DL_STATE_NONE:
431 output = "not tracked";
432 break;
433 case DL_STATE_DORMANT:
434 output = "dormant";
435 break;
436 case DL_STATE_AVAILABLE:
437 output = "available";
438 break;
439 case DL_STATE_CONSUMER_PROBE:
440 output = "consumer probing";
441 break;
442 case DL_STATE_ACTIVE:
443 output = "active";
444 break;
445 case DL_STATE_SUPPLIER_UNBIND:
446 output = "supplier unbinding";
447 break;
448 default:
449 output = "unknown";
450 break;
451 }
452
453 return sysfs_emit(buf, "%s\n", output);
454}
455static DEVICE_ATTR_RO(status);
456
457static ssize_t auto_remove_on_show(struct device *dev,
458 struct device_attribute *attr, char *buf)
459{
460 struct device_link *link = to_devlink(dev);
461 const char *output;
462
463 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
464 output = "supplier unbind";
465 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
466 output = "consumer unbind";
467 else
468 output = "never";
469
470 return sysfs_emit(buf, "%s\n", output);
471}
472static DEVICE_ATTR_RO(auto_remove_on);
473
474static ssize_t runtime_pm_show(struct device *dev,
475 struct device_attribute *attr, char *buf)
476{
477 struct device_link *link = to_devlink(dev);
478
479 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
480}
481static DEVICE_ATTR_RO(runtime_pm);
482
483static ssize_t sync_state_only_show(struct device *dev,
484 struct device_attribute *attr, char *buf)
485{
486 struct device_link *link = to_devlink(dev);
487
488 return sysfs_emit(buf, "%d\n",
489 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
490}
491static DEVICE_ATTR_RO(sync_state_only);
492
493static struct attribute *devlink_attrs[] = {
494 &dev_attr_status.attr,
495 &dev_attr_auto_remove_on.attr,
496 &dev_attr_runtime_pm.attr,
497 &dev_attr_sync_state_only.attr,
498 NULL,
499};
500ATTRIBUTE_GROUPS(devlink);
501
502static void device_link_release_fn(struct work_struct *work)
503{
504 struct device_link *link = container_of(work, struct device_link, rm_work);
505
506 /* Ensure that all references to the link object have been dropped. */
507 device_link_synchronize_removal();
508
509 pm_runtime_release_supplier(link);
510 /*
511 * If supplier_preactivated is set, the link has been dropped between
512 * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
513 * in __driver_probe_device(). In that case, drop the supplier's
514 * PM-runtime usage counter to remove the reference taken by
515 * pm_runtime_get_suppliers().
516 */
517 if (link->supplier_preactivated)
518 pm_runtime_put_noidle(link->supplier);
519
520 pm_request_idle(link->supplier);
521
522 put_device(link->consumer);
523 put_device(link->supplier);
524 kfree(link);
525}
526
527static void devlink_dev_release(struct device *dev)
528{
529 struct device_link *link = to_devlink(dev);
530
531 INIT_WORK(&link->rm_work, device_link_release_fn);
532 /*
533 * It may take a while to complete this work because of the SRCU
534 * synchronization in device_link_release_fn() and if the consumer or
535 * supplier devices get deleted when it runs, so put it into the
536 * dedicated workqueue.
537 */
538 queue_work(device_link_wq, &link->rm_work);
539}
540
541/**
542 * device_link_wait_removal - Wait for ongoing devlink removal jobs to terminate
543 */
544void device_link_wait_removal(void)
545{
546 /*
547 * devlink removal jobs are queued in the dedicated work queue.
548 * To be sure that all removal jobs are terminated, ensure that any
549 * scheduled work has run to completion.
550 */
551 flush_workqueue(device_link_wq);
552}
553EXPORT_SYMBOL_GPL(device_link_wait_removal);
554
555static const struct class devlink_class = {
556 .name = "devlink",
557 .dev_groups = devlink_groups,
558 .dev_release = devlink_dev_release,
559};
560
561static int devlink_add_symlinks(struct device *dev)
562{
563 char *buf_con __free(kfree) = NULL, *buf_sup __free(kfree) = NULL;
564 int ret;
565 struct device_link *link = to_devlink(dev);
566 struct device *sup = link->supplier;
567 struct device *con = link->consumer;
568
569 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
570 if (ret)
571 goto out;
572
573 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
574 if (ret)
575 goto err_con;
576
577 buf_con = kasprintf(GFP_KERNEL, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
578 if (!buf_con) {
579 ret = -ENOMEM;
580 goto err_con_dev;
581 }
582
583 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf_con);
584 if (ret)
585 goto err_con_dev;
586
587 buf_sup = kasprintf(GFP_KERNEL, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
588 if (!buf_sup) {
589 ret = -ENOMEM;
590 goto err_sup_dev;
591 }
592
593 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf_sup);
594 if (ret)
595 goto err_sup_dev;
596
597 goto out;
598
599err_sup_dev:
600 sysfs_remove_link(&sup->kobj, buf_con);
601err_con_dev:
602 sysfs_remove_link(&link->link_dev.kobj, "consumer");
603err_con:
604 sysfs_remove_link(&link->link_dev.kobj, "supplier");
605out:
606 return ret;
607}
608
609static void devlink_remove_symlinks(struct device *dev)
610{
611 char *buf_con __free(kfree) = NULL, *buf_sup __free(kfree) = NULL;
612 struct device_link *link = to_devlink(dev);
613 struct device *sup = link->supplier;
614 struct device *con = link->consumer;
615
616 sysfs_remove_link(&link->link_dev.kobj, "consumer");
617 sysfs_remove_link(&link->link_dev.kobj, "supplier");
618
619 if (device_is_registered(con)) {
620 buf_sup = kasprintf(GFP_KERNEL, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
621 if (!buf_sup)
622 goto out;
623 sysfs_remove_link(&con->kobj, buf_sup);
624 }
625
626 buf_con = kasprintf(GFP_KERNEL, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
627 if (!buf_con)
628 goto out;
629 sysfs_remove_link(&sup->kobj, buf_con);
630
631 return;
632
633out:
634 WARN(1, "Unable to properly free device link symlinks!\n");
635}
636
637static struct class_interface devlink_class_intf = {
638 .class = &devlink_class,
639 .add_dev = devlink_add_symlinks,
640 .remove_dev = devlink_remove_symlinks,
641};
642
643static int __init devlink_class_init(void)
644{
645 int ret;
646
647 ret = class_register(&devlink_class);
648 if (ret)
649 return ret;
650
651 ret = class_interface_register(&devlink_class_intf);
652 if (ret)
653 class_unregister(&devlink_class);
654
655 return ret;
656}
657postcore_initcall(devlink_class_init);
658
659#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
660 DL_FLAG_AUTOREMOVE_SUPPLIER | \
661 DL_FLAG_AUTOPROBE_CONSUMER | \
662 DL_FLAG_SYNC_STATE_ONLY | \
663 DL_FLAG_INFERRED | \
664 DL_FLAG_CYCLE)
665
666#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
667 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
668
669/**
670 * device_link_add - Create a link between two devices.
671 * @consumer: Consumer end of the link.
672 * @supplier: Supplier end of the link.
673 * @flags: Link flags.
674 *
675 * Return: On success, a device_link struct will be returned.
676 * On error or invalid flag settings, NULL will be returned.
677 *
678 * The caller is responsible for the proper synchronization of the link creation
679 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
680 * runtime PM framework to take the link into account. Second, if the
681 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
682 * be forced into the active meta state and reference-counted upon the creation
683 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
684 * ignored.
685 *
686 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
687 * expected to release the link returned by it directly with the help of either
688 * device_link_del() or device_link_remove().
689 *
690 * If that flag is not set, however, the caller of this function is handing the
691 * management of the link over to the driver core entirely and its return value
692 * can only be used to check whether or not the link is present. In that case,
693 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
694 * flags can be used to indicate to the driver core when the link can be safely
695 * deleted. Namely, setting one of them in @flags indicates to the driver core
696 * that the link is not going to be used (by the given caller of this function)
697 * after unbinding the consumer or supplier driver, respectively, from its
698 * device, so the link can be deleted at that point. If none of them is set,
699 * the link will be maintained until one of the devices pointed to by it (either
700 * the consumer or the supplier) is unregistered.
701 *
702 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
703 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
704 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
705 * be used to request the driver core to automatically probe for a consumer
706 * driver after successfully binding a driver to the supplier device.
707 *
708 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
709 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
710 * the same time is invalid and will cause NULL to be returned upfront.
711 * However, if a device link between the given @consumer and @supplier pair
712 * exists already when this function is called for them, the existing link will
713 * be returned regardless of its current type and status (the link's flags may
714 * be modified then). The caller of this function is then expected to treat
715 * the link as though it has just been created, so (in particular) if
716 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
717 * explicitly when not needed any more (as stated above).
718 *
719 * A side effect of the link creation is re-ordering of dpm_list and the
720 * devices_kset list by moving the consumer device and all devices depending
721 * on it to the ends of these lists (that does not happen to devices that have
722 * not been registered when this function is called).
723 *
724 * The supplier device is required to be registered when this function is called
725 * and NULL will be returned if that is not the case. The consumer device need
726 * not be registered, however.
727 */
728struct device_link *device_link_add(struct device *consumer,
729 struct device *supplier, u32 flags)
730{
731 struct device_link *link;
732
733 if (!consumer || !supplier || consumer == supplier ||
734 flags & ~DL_ADD_VALID_FLAGS ||
735 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
736 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
737 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
738 DL_FLAG_AUTOREMOVE_SUPPLIER)))
739 return NULL;
740
741 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
742 if (pm_runtime_get_sync(supplier) < 0) {
743 pm_runtime_put_noidle(supplier);
744 return NULL;
745 }
746 }
747
748 if (!(flags & DL_FLAG_STATELESS))
749 flags |= DL_FLAG_MANAGED;
750
751 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
752 !device_link_flag_is_sync_state_only(flags))
753 return NULL;
754
755 device_links_write_lock();
756 device_pm_lock();
757
758 /*
759 * If the supplier has not been fully registered yet or there is a
760 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
761 * the supplier already in the graph, return NULL. If the link is a
762 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
763 * because it only affects sync_state() callbacks.
764 */
765 if (!device_pm_initialized(supplier)
766 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
767 device_is_dependent(consumer, supplier))) {
768 link = NULL;
769 goto out;
770 }
771
772 /*
773 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
774 * So, only create it if the consumer hasn't probed yet.
775 */
776 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
777 consumer->links.status != DL_DEV_NO_DRIVER &&
778 consumer->links.status != DL_DEV_PROBING) {
779 link = NULL;
780 goto out;
781 }
782
783 /*
784 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
785 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
786 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
787 */
788 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
789 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
790
791 list_for_each_entry(link, &supplier->links.consumers, s_node) {
792 if (link->consumer != consumer)
793 continue;
794
795 if (link->flags & DL_FLAG_INFERRED &&
796 !(flags & DL_FLAG_INFERRED))
797 link->flags &= ~DL_FLAG_INFERRED;
798
799 if (flags & DL_FLAG_PM_RUNTIME) {
800 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
801 pm_runtime_new_link(consumer);
802 link->flags |= DL_FLAG_PM_RUNTIME;
803 }
804 if (flags & DL_FLAG_RPM_ACTIVE)
805 refcount_inc(&link->rpm_active);
806 }
807
808 if (flags & DL_FLAG_STATELESS) {
809 kref_get(&link->kref);
810 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
811 !(link->flags & DL_FLAG_STATELESS)) {
812 link->flags |= DL_FLAG_STATELESS;
813 goto reorder;
814 } else {
815 link->flags |= DL_FLAG_STATELESS;
816 goto out;
817 }
818 }
819
820 /*
821 * If the life time of the link following from the new flags is
822 * longer than indicated by the flags of the existing link,
823 * update the existing link to stay around longer.
824 */
825 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
826 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
827 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
828 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
829 }
830 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
831 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
832 DL_FLAG_AUTOREMOVE_SUPPLIER);
833 }
834 if (!(link->flags & DL_FLAG_MANAGED)) {
835 kref_get(&link->kref);
836 link->flags |= DL_FLAG_MANAGED;
837 device_link_init_status(link, consumer, supplier);
838 }
839 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
840 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
841 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
842 goto reorder;
843 }
844
845 goto out;
846 }
847
848 link = kzalloc(sizeof(*link), GFP_KERNEL);
849 if (!link)
850 goto out;
851
852 refcount_set(&link->rpm_active, 1);
853
854 get_device(supplier);
855 link->supplier = supplier;
856 INIT_LIST_HEAD(&link->s_node);
857 get_device(consumer);
858 link->consumer = consumer;
859 INIT_LIST_HEAD(&link->c_node);
860 link->flags = flags;
861 kref_init(&link->kref);
862
863 link->link_dev.class = &devlink_class;
864 device_set_pm_not_required(&link->link_dev);
865 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
866 dev_bus_name(supplier), dev_name(supplier),
867 dev_bus_name(consumer), dev_name(consumer));
868 if (device_register(&link->link_dev)) {
869 put_device(&link->link_dev);
870 link = NULL;
871 goto out;
872 }
873
874 if (flags & DL_FLAG_PM_RUNTIME) {
875 if (flags & DL_FLAG_RPM_ACTIVE)
876 refcount_inc(&link->rpm_active);
877
878 pm_runtime_new_link(consumer);
879 }
880
881 /* Determine the initial link state. */
882 if (flags & DL_FLAG_STATELESS)
883 link->status = DL_STATE_NONE;
884 else
885 device_link_init_status(link, consumer, supplier);
886
887 /*
888 * Some callers expect the link creation during consumer driver probe to
889 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
890 */
891 if (link->status == DL_STATE_CONSUMER_PROBE &&
892 flags & DL_FLAG_PM_RUNTIME)
893 pm_runtime_resume(supplier);
894
895 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
896 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
897
898 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
899 dev_dbg(consumer,
900 "Linked as a sync state only consumer to %s\n",
901 dev_name(supplier));
902 goto out;
903 }
904
905reorder:
906 /*
907 * Move the consumer and all of the devices depending on it to the end
908 * of dpm_list and the devices_kset list.
909 *
910 * It is necessary to hold dpm_list locked throughout all that or else
911 * we may end up suspending with a wrong ordering of it.
912 */
913 device_reorder_to_tail(consumer, NULL);
914
915 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
916
917out:
918 device_pm_unlock();
919 device_links_write_unlock();
920
921 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
922 pm_runtime_put(supplier);
923
924 return link;
925}
926EXPORT_SYMBOL_GPL(device_link_add);
927
928static void __device_link_del(struct kref *kref)
929{
930 struct device_link *link = container_of(kref, struct device_link, kref);
931
932 dev_dbg(link->consumer, "Dropping the link to %s\n",
933 dev_name(link->supplier));
934
935 pm_runtime_drop_link(link);
936
937 device_link_remove_from_lists(link);
938 device_unregister(&link->link_dev);
939}
940
941static void device_link_put_kref(struct device_link *link)
942{
943 if (link->flags & DL_FLAG_STATELESS)
944 kref_put(&link->kref, __device_link_del);
945 else if (!device_is_registered(link->consumer))
946 __device_link_del(&link->kref);
947 else
948 WARN(1, "Unable to drop a managed device link reference\n");
949}
950
951/**
952 * device_link_del - Delete a stateless link between two devices.
953 * @link: Device link to delete.
954 *
955 * The caller must ensure proper synchronization of this function with runtime
956 * PM. If the link was added multiple times, it needs to be deleted as often.
957 * Care is required for hotplugged devices: Their links are purged on removal
958 * and calling device_link_del() is then no longer allowed.
959 */
960void device_link_del(struct device_link *link)
961{
962 device_links_write_lock();
963 device_link_put_kref(link);
964 device_links_write_unlock();
965}
966EXPORT_SYMBOL_GPL(device_link_del);
967
968/**
969 * device_link_remove - Delete a stateless link between two devices.
970 * @consumer: Consumer end of the link.
971 * @supplier: Supplier end of the link.
972 *
973 * The caller must ensure proper synchronization of this function with runtime
974 * PM.
975 */
976void device_link_remove(void *consumer, struct device *supplier)
977{
978 struct device_link *link;
979
980 if (WARN_ON(consumer == supplier))
981 return;
982
983 device_links_write_lock();
984
985 list_for_each_entry(link, &supplier->links.consumers, s_node) {
986 if (link->consumer == consumer) {
987 device_link_put_kref(link);
988 break;
989 }
990 }
991
992 device_links_write_unlock();
993}
994EXPORT_SYMBOL_GPL(device_link_remove);
995
996static void device_links_missing_supplier(struct device *dev)
997{
998 struct device_link *link;
999
1000 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1001 if (link->status != DL_STATE_CONSUMER_PROBE)
1002 continue;
1003
1004 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1005 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1006 } else {
1007 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1008 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1009 }
1010 }
1011}
1012
1013static bool dev_is_best_effort(struct device *dev)
1014{
1015 return (fw_devlink_best_effort && dev->can_match) ||
1016 (dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
1017}
1018
1019static struct fwnode_handle *fwnode_links_check_suppliers(
1020 struct fwnode_handle *fwnode)
1021{
1022 struct fwnode_link *link;
1023
1024 if (!fwnode || fw_devlink_is_permissive())
1025 return NULL;
1026
1027 list_for_each_entry(link, &fwnode->suppliers, c_hook)
1028 if (!(link->flags &
1029 (FWLINK_FLAG_CYCLE | FWLINK_FLAG_IGNORE)))
1030 return link->supplier;
1031
1032 return NULL;
1033}
1034
1035/**
1036 * device_links_check_suppliers - Check presence of supplier drivers.
1037 * @dev: Consumer device.
1038 *
1039 * Check links from this device to any suppliers. Walk the list of the device's
1040 * links to suppliers and see if all of them are available. If not, simply
1041 * return -EPROBE_DEFER.
1042 *
1043 * We need to guarantee that the supplier will not go away after the check has
1044 * been positive here. It only can go away in __device_release_driver() and
1045 * that function checks the device's links to consumers. This means we need to
1046 * mark the link as "consumer probe in progress" to make the supplier removal
1047 * wait for us to complete (or bad things may happen).
1048 *
1049 * Links without the DL_FLAG_MANAGED flag set are ignored.
1050 */
1051int device_links_check_suppliers(struct device *dev)
1052{
1053 struct device_link *link;
1054 int ret = 0, fwnode_ret = 0;
1055 struct fwnode_handle *sup_fw;
1056
1057 /*
1058 * Device waiting for supplier to become available is not allowed to
1059 * probe.
1060 */
1061 scoped_guard(mutex, &fwnode_link_lock) {
1062 sup_fw = fwnode_links_check_suppliers(dev->fwnode);
1063 if (sup_fw) {
1064 if (dev_is_best_effort(dev))
1065 fwnode_ret = -EAGAIN;
1066 else
1067 return dev_err_probe(dev, -EPROBE_DEFER,
1068 "wait for supplier %pfwf\n", sup_fw);
1069 }
1070 }
1071
1072 device_links_write_lock();
1073
1074 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1075 if (!(link->flags & DL_FLAG_MANAGED))
1076 continue;
1077
1078 if (link->status != DL_STATE_AVAILABLE &&
1079 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1080
1081 if (dev_is_best_effort(dev) &&
1082 link->flags & DL_FLAG_INFERRED &&
1083 !link->supplier->can_match) {
1084 ret = -EAGAIN;
1085 continue;
1086 }
1087
1088 device_links_missing_supplier(dev);
1089 ret = dev_err_probe(dev, -EPROBE_DEFER,
1090 "supplier %s not ready\n", dev_name(link->supplier));
1091 break;
1092 }
1093 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1094 }
1095 dev->links.status = DL_DEV_PROBING;
1096
1097 device_links_write_unlock();
1098
1099 return ret ? ret : fwnode_ret;
1100}
1101
1102/**
1103 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1104 * @dev: Device to call sync_state() on
1105 * @list: List head to queue the @dev on
1106 *
1107 * Queues a device for a sync_state() callback when the device links write lock
1108 * isn't held. This allows the sync_state() execution flow to use device links
1109 * APIs. The caller must ensure this function is called with
1110 * device_links_write_lock() held.
1111 *
1112 * This function does a get_device() to make sure the device is not freed while
1113 * on this list.
1114 *
1115 * So the caller must also ensure that device_links_flush_sync_list() is called
1116 * as soon as the caller releases device_links_write_lock(). This is necessary
1117 * to make sure the sync_state() is called in a timely fashion and the
1118 * put_device() is called on this device.
1119 */
1120static void __device_links_queue_sync_state(struct device *dev,
1121 struct list_head *list)
1122{
1123 struct device_link *link;
1124
1125 if (!dev_has_sync_state(dev))
1126 return;
1127 if (dev->state_synced)
1128 return;
1129
1130 list_for_each_entry(link, &dev->links.consumers, s_node) {
1131 if (!(link->flags & DL_FLAG_MANAGED))
1132 continue;
1133 if (link->status != DL_STATE_ACTIVE)
1134 return;
1135 }
1136
1137 /*
1138 * Set the flag here to avoid adding the same device to a list more
1139 * than once. This can happen if new consumers get added to the device
1140 * and probed before the list is flushed.
1141 */
1142 dev->state_synced = true;
1143
1144 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1145 return;
1146
1147 get_device(dev);
1148 list_add_tail(&dev->links.defer_sync, list);
1149}
1150
1151/**
1152 * device_links_flush_sync_list - Call sync_state() on a list of devices
1153 * @list: List of devices to call sync_state() on
1154 * @dont_lock_dev: Device for which lock is already held by the caller
1155 *
1156 * Calls sync_state() on all the devices that have been queued for it. This
1157 * function is used in conjunction with __device_links_queue_sync_state(). The
1158 * @dont_lock_dev parameter is useful when this function is called from a
1159 * context where a device lock is already held.
1160 */
1161static void device_links_flush_sync_list(struct list_head *list,
1162 struct device *dont_lock_dev)
1163{
1164 struct device *dev, *tmp;
1165
1166 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1167 list_del_init(&dev->links.defer_sync);
1168
1169 if (dev != dont_lock_dev)
1170 device_lock(dev);
1171
1172 dev_sync_state(dev);
1173
1174 if (dev != dont_lock_dev)
1175 device_unlock(dev);
1176
1177 put_device(dev);
1178 }
1179}
1180
1181void device_links_supplier_sync_state_pause(void)
1182{
1183 device_links_write_lock();
1184 defer_sync_state_count++;
1185 device_links_write_unlock();
1186}
1187
1188void device_links_supplier_sync_state_resume(void)
1189{
1190 struct device *dev, *tmp;
1191 LIST_HEAD(sync_list);
1192
1193 device_links_write_lock();
1194 if (!defer_sync_state_count) {
1195 WARN(true, "Unmatched sync_state pause/resume!");
1196 goto out;
1197 }
1198 defer_sync_state_count--;
1199 if (defer_sync_state_count)
1200 goto out;
1201
1202 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1203 /*
1204 * Delete from deferred_sync list before queuing it to
1205 * sync_list because defer_sync is used for both lists.
1206 */
1207 list_del_init(&dev->links.defer_sync);
1208 __device_links_queue_sync_state(dev, &sync_list);
1209 }
1210out:
1211 device_links_write_unlock();
1212
1213 device_links_flush_sync_list(&sync_list, NULL);
1214}
1215
1216static int sync_state_resume_initcall(void)
1217{
1218 device_links_supplier_sync_state_resume();
1219 return 0;
1220}
1221late_initcall(sync_state_resume_initcall);
1222
1223static void __device_links_supplier_defer_sync(struct device *sup)
1224{
1225 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1226 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1227}
1228
1229static void device_link_drop_managed(struct device_link *link)
1230{
1231 link->flags &= ~DL_FLAG_MANAGED;
1232 WRITE_ONCE(link->status, DL_STATE_NONE);
1233 kref_put(&link->kref, __device_link_del);
1234}
1235
1236static ssize_t waiting_for_supplier_show(struct device *dev,
1237 struct device_attribute *attr,
1238 char *buf)
1239{
1240 bool val;
1241
1242 device_lock(dev);
1243 scoped_guard(mutex, &fwnode_link_lock)
1244 val = !!fwnode_links_check_suppliers(dev->fwnode);
1245 device_unlock(dev);
1246 return sysfs_emit(buf, "%u\n", val);
1247}
1248static DEVICE_ATTR_RO(waiting_for_supplier);
1249
1250/**
1251 * device_links_force_bind - Prepares device to be force bound
1252 * @dev: Consumer device.
1253 *
1254 * device_bind_driver() force binds a device to a driver without calling any
1255 * driver probe functions. So the consumer really isn't going to wait for any
1256 * supplier before it's bound to the driver. We still want the device link
1257 * states to be sensible when this happens.
1258 *
1259 * In preparation for device_bind_driver(), this function goes through each
1260 * supplier device links and checks if the supplier is bound. If it is, then
1261 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1262 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1263 */
1264void device_links_force_bind(struct device *dev)
1265{
1266 struct device_link *link, *ln;
1267
1268 device_links_write_lock();
1269
1270 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1271 if (!(link->flags & DL_FLAG_MANAGED))
1272 continue;
1273
1274 if (link->status != DL_STATE_AVAILABLE) {
1275 device_link_drop_managed(link);
1276 continue;
1277 }
1278 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1279 }
1280 dev->links.status = DL_DEV_PROBING;
1281
1282 device_links_write_unlock();
1283}
1284
1285/**
1286 * device_links_driver_bound - Update device links after probing its driver.
1287 * @dev: Device to update the links for.
1288 *
1289 * The probe has been successful, so update links from this device to any
1290 * consumers by changing their status to "available".
1291 *
1292 * Also change the status of @dev's links to suppliers to "active".
1293 *
1294 * Links without the DL_FLAG_MANAGED flag set are ignored.
1295 */
1296void device_links_driver_bound(struct device *dev)
1297{
1298 struct device_link *link, *ln;
1299 LIST_HEAD(sync_list);
1300
1301 /*
1302 * If a device binds successfully, it's expected to have created all
1303 * the device links it needs to or make new device links as it needs
1304 * them. So, fw_devlink no longer needs to create device links to any
1305 * of the device's suppliers.
1306 *
1307 * Also, if a child firmware node of this bound device is not added as a
1308 * device by now, assume it is never going to be added. Make this bound
1309 * device the fallback supplier to the dangling consumers of the child
1310 * firmware node because this bound device is probably implementing the
1311 * child firmware node functionality and we don't want the dangling
1312 * consumers to defer probe indefinitely waiting for a device for the
1313 * child firmware node.
1314 */
1315 if (dev->fwnode && dev->fwnode->dev == dev) {
1316 struct fwnode_handle *child;
1317
1318 fwnode_links_purge_suppliers(dev->fwnode);
1319
1320 guard(mutex)(&fwnode_link_lock);
1321
1322 fwnode_for_each_available_child_node(dev->fwnode, child)
1323 __fw_devlink_pickup_dangling_consumers(child,
1324 dev->fwnode);
1325 __fw_devlink_link_to_consumers(dev);
1326 }
1327 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1328
1329 device_links_write_lock();
1330
1331 list_for_each_entry(link, &dev->links.consumers, s_node) {
1332 if (!(link->flags & DL_FLAG_MANAGED))
1333 continue;
1334
1335 /*
1336 * Links created during consumer probe may be in the "consumer
1337 * probe" state to start with if the supplier is still probing
1338 * when they are created and they may become "active" if the
1339 * consumer probe returns first. Skip them here.
1340 */
1341 if (link->status == DL_STATE_CONSUMER_PROBE ||
1342 link->status == DL_STATE_ACTIVE)
1343 continue;
1344
1345 WARN_ON(link->status != DL_STATE_DORMANT);
1346 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1347
1348 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1349 driver_deferred_probe_add(link->consumer);
1350 }
1351
1352 if (defer_sync_state_count)
1353 __device_links_supplier_defer_sync(dev);
1354 else
1355 __device_links_queue_sync_state(dev, &sync_list);
1356
1357 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1358 struct device *supplier;
1359
1360 if (!(link->flags & DL_FLAG_MANAGED))
1361 continue;
1362
1363 supplier = link->supplier;
1364 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1365 /*
1366 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1367 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1368 * save to drop the managed link completely.
1369 */
1370 device_link_drop_managed(link);
1371 } else if (dev_is_best_effort(dev) &&
1372 link->flags & DL_FLAG_INFERRED &&
1373 link->status != DL_STATE_CONSUMER_PROBE &&
1374 !link->supplier->can_match) {
1375 /*
1376 * When dev_is_best_effort() is true, we ignore device
1377 * links to suppliers that don't have a driver. If the
1378 * consumer device still managed to probe, there's no
1379 * point in maintaining a device link in a weird state
1380 * (consumer probed before supplier). So delete it.
1381 */
1382 device_link_drop_managed(link);
1383 } else {
1384 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1385 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1386 }
1387
1388 /*
1389 * This needs to be done even for the deleted
1390 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1391 * device link that was preventing the supplier from getting a
1392 * sync_state() call.
1393 */
1394 if (defer_sync_state_count)
1395 __device_links_supplier_defer_sync(supplier);
1396 else
1397 __device_links_queue_sync_state(supplier, &sync_list);
1398 }
1399
1400 dev->links.status = DL_DEV_DRIVER_BOUND;
1401
1402 device_links_write_unlock();
1403
1404 device_links_flush_sync_list(&sync_list, dev);
1405}
1406
1407/**
1408 * __device_links_no_driver - Update links of a device without a driver.
1409 * @dev: Device without a drvier.
1410 *
1411 * Delete all non-persistent links from this device to any suppliers.
1412 *
1413 * Persistent links stay around, but their status is changed to "available",
1414 * unless they already are in the "supplier unbind in progress" state in which
1415 * case they need not be updated.
1416 *
1417 * Links without the DL_FLAG_MANAGED flag set are ignored.
1418 */
1419static void __device_links_no_driver(struct device *dev)
1420{
1421 struct device_link *link, *ln;
1422
1423 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1424 if (!(link->flags & DL_FLAG_MANAGED))
1425 continue;
1426
1427 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1428 device_link_drop_managed(link);
1429 continue;
1430 }
1431
1432 if (link->status != DL_STATE_CONSUMER_PROBE &&
1433 link->status != DL_STATE_ACTIVE)
1434 continue;
1435
1436 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1437 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1438 } else {
1439 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1440 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1441 }
1442 }
1443
1444 dev->links.status = DL_DEV_NO_DRIVER;
1445}
1446
1447/**
1448 * device_links_no_driver - Update links after failing driver probe.
1449 * @dev: Device whose driver has just failed to probe.
1450 *
1451 * Clean up leftover links to consumers for @dev and invoke
1452 * %__device_links_no_driver() to update links to suppliers for it as
1453 * appropriate.
1454 *
1455 * Links without the DL_FLAG_MANAGED flag set are ignored.
1456 */
1457void device_links_no_driver(struct device *dev)
1458{
1459 struct device_link *link;
1460
1461 device_links_write_lock();
1462
1463 list_for_each_entry(link, &dev->links.consumers, s_node) {
1464 if (!(link->flags & DL_FLAG_MANAGED))
1465 continue;
1466
1467 /*
1468 * The probe has failed, so if the status of the link is
1469 * "consumer probe" or "active", it must have been added by
1470 * a probing consumer while this device was still probing.
1471 * Change its state to "dormant", as it represents a valid
1472 * relationship, but it is not functionally meaningful.
1473 */
1474 if (link->status == DL_STATE_CONSUMER_PROBE ||
1475 link->status == DL_STATE_ACTIVE)
1476 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1477 }
1478
1479 __device_links_no_driver(dev);
1480
1481 device_links_write_unlock();
1482}
1483
1484/**
1485 * device_links_driver_cleanup - Update links after driver removal.
1486 * @dev: Device whose driver has just gone away.
1487 *
1488 * Update links to consumers for @dev by changing their status to "dormant" and
1489 * invoke %__device_links_no_driver() to update links to suppliers for it as
1490 * appropriate.
1491 *
1492 * Links without the DL_FLAG_MANAGED flag set are ignored.
1493 */
1494void device_links_driver_cleanup(struct device *dev)
1495{
1496 struct device_link *link, *ln;
1497
1498 device_links_write_lock();
1499
1500 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1501 if (!(link->flags & DL_FLAG_MANAGED))
1502 continue;
1503
1504 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1505 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1506
1507 /*
1508 * autoremove the links between this @dev and its consumer
1509 * devices that are not active, i.e. where the link state
1510 * has moved to DL_STATE_SUPPLIER_UNBIND.
1511 */
1512 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1513 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1514 device_link_drop_managed(link);
1515
1516 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1517 }
1518
1519 list_del_init(&dev->links.defer_sync);
1520 __device_links_no_driver(dev);
1521
1522 device_links_write_unlock();
1523}
1524
1525/**
1526 * device_links_busy - Check if there are any busy links to consumers.
1527 * @dev: Device to check.
1528 *
1529 * Check each consumer of the device and return 'true' if its link's status
1530 * is one of "consumer probe" or "active" (meaning that the given consumer is
1531 * probing right now or its driver is present). Otherwise, change the link
1532 * state to "supplier unbind" to prevent the consumer from being probed
1533 * successfully going forward.
1534 *
1535 * Return 'false' if there are no probing or active consumers.
1536 *
1537 * Links without the DL_FLAG_MANAGED flag set are ignored.
1538 */
1539bool device_links_busy(struct device *dev)
1540{
1541 struct device_link *link;
1542 bool ret = false;
1543
1544 device_links_write_lock();
1545
1546 list_for_each_entry(link, &dev->links.consumers, s_node) {
1547 if (!(link->flags & DL_FLAG_MANAGED))
1548 continue;
1549
1550 if (link->status == DL_STATE_CONSUMER_PROBE
1551 || link->status == DL_STATE_ACTIVE) {
1552 ret = true;
1553 break;
1554 }
1555 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1556 }
1557
1558 dev->links.status = DL_DEV_UNBINDING;
1559
1560 device_links_write_unlock();
1561 return ret;
1562}
1563
1564/**
1565 * device_links_unbind_consumers - Force unbind consumers of the given device.
1566 * @dev: Device to unbind the consumers of.
1567 *
1568 * Walk the list of links to consumers for @dev and if any of them is in the
1569 * "consumer probe" state, wait for all device probes in progress to complete
1570 * and start over.
1571 *
1572 * If that's not the case, change the status of the link to "supplier unbind"
1573 * and check if the link was in the "active" state. If so, force the consumer
1574 * driver to unbind and start over (the consumer will not re-probe as we have
1575 * changed the state of the link already).
1576 *
1577 * Links without the DL_FLAG_MANAGED flag set are ignored.
1578 */
1579void device_links_unbind_consumers(struct device *dev)
1580{
1581 struct device_link *link;
1582
1583 start:
1584 device_links_write_lock();
1585
1586 list_for_each_entry(link, &dev->links.consumers, s_node) {
1587 enum device_link_state status;
1588
1589 if (!(link->flags & DL_FLAG_MANAGED) ||
1590 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1591 continue;
1592
1593 status = link->status;
1594 if (status == DL_STATE_CONSUMER_PROBE) {
1595 device_links_write_unlock();
1596
1597 wait_for_device_probe();
1598 goto start;
1599 }
1600 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1601 if (status == DL_STATE_ACTIVE) {
1602 struct device *consumer = link->consumer;
1603
1604 get_device(consumer);
1605
1606 device_links_write_unlock();
1607
1608 device_release_driver_internal(consumer, NULL,
1609 consumer->parent);
1610 put_device(consumer);
1611 goto start;
1612 }
1613 }
1614
1615 device_links_write_unlock();
1616}
1617
1618/**
1619 * device_links_purge - Delete existing links to other devices.
1620 * @dev: Target device.
1621 */
1622static void device_links_purge(struct device *dev)
1623{
1624 struct device_link *link, *ln;
1625
1626 if (dev->class == &devlink_class)
1627 return;
1628
1629 /*
1630 * Delete all of the remaining links from this device to any other
1631 * devices (either consumers or suppliers).
1632 */
1633 device_links_write_lock();
1634
1635 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1636 WARN_ON(link->status == DL_STATE_ACTIVE);
1637 __device_link_del(&link->kref);
1638 }
1639
1640 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1641 WARN_ON(link->status != DL_STATE_DORMANT &&
1642 link->status != DL_STATE_NONE);
1643 __device_link_del(&link->kref);
1644 }
1645
1646 device_links_write_unlock();
1647}
1648
1649#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1650 DL_FLAG_SYNC_STATE_ONLY)
1651#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1652 DL_FLAG_AUTOPROBE_CONSUMER)
1653#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1654 DL_FLAG_PM_RUNTIME)
1655
1656static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1657static int __init fw_devlink_setup(char *arg)
1658{
1659 if (!arg)
1660 return -EINVAL;
1661
1662 if (strcmp(arg, "off") == 0) {
1663 fw_devlink_flags = 0;
1664 } else if (strcmp(arg, "permissive") == 0) {
1665 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1666 } else if (strcmp(arg, "on") == 0) {
1667 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1668 } else if (strcmp(arg, "rpm") == 0) {
1669 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1670 }
1671 return 0;
1672}
1673early_param("fw_devlink", fw_devlink_setup);
1674
1675static bool fw_devlink_strict;
1676static int __init fw_devlink_strict_setup(char *arg)
1677{
1678 return kstrtobool(arg, &fw_devlink_strict);
1679}
1680early_param("fw_devlink.strict", fw_devlink_strict_setup);
1681
1682#define FW_DEVLINK_SYNC_STATE_STRICT 0
1683#define FW_DEVLINK_SYNC_STATE_TIMEOUT 1
1684
1685#ifndef CONFIG_FW_DEVLINK_SYNC_STATE_TIMEOUT
1686static int fw_devlink_sync_state;
1687#else
1688static int fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1689#endif
1690
1691static int __init fw_devlink_sync_state_setup(char *arg)
1692{
1693 if (!arg)
1694 return -EINVAL;
1695
1696 if (strcmp(arg, "strict") == 0) {
1697 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_STRICT;
1698 return 0;
1699 } else if (strcmp(arg, "timeout") == 0) {
1700 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1701 return 0;
1702 }
1703 return -EINVAL;
1704}
1705early_param("fw_devlink.sync_state", fw_devlink_sync_state_setup);
1706
1707static inline u32 fw_devlink_get_flags(u8 fwlink_flags)
1708{
1709 if (fwlink_flags & FWLINK_FLAG_CYCLE)
1710 return FW_DEVLINK_FLAGS_PERMISSIVE | DL_FLAG_CYCLE;
1711
1712 return fw_devlink_flags;
1713}
1714
1715static bool fw_devlink_is_permissive(void)
1716{
1717 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1718}
1719
1720bool fw_devlink_is_strict(void)
1721{
1722 return fw_devlink_strict && !fw_devlink_is_permissive();
1723}
1724
1725static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1726{
1727 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1728 return;
1729
1730 fwnode_call_int_op(fwnode, add_links);
1731 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1732}
1733
1734static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1735{
1736 struct fwnode_handle *child = NULL;
1737
1738 fw_devlink_parse_fwnode(fwnode);
1739
1740 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1741 fw_devlink_parse_fwtree(child);
1742}
1743
1744static void fw_devlink_relax_link(struct device_link *link)
1745{
1746 if (!(link->flags & DL_FLAG_INFERRED))
1747 return;
1748
1749 if (device_link_flag_is_sync_state_only(link->flags))
1750 return;
1751
1752 pm_runtime_drop_link(link);
1753 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1754 dev_dbg(link->consumer, "Relaxing link with %s\n",
1755 dev_name(link->supplier));
1756}
1757
1758static int fw_devlink_no_driver(struct device *dev, void *data)
1759{
1760 struct device_link *link = to_devlink(dev);
1761
1762 if (!link->supplier->can_match)
1763 fw_devlink_relax_link(link);
1764
1765 return 0;
1766}
1767
1768void fw_devlink_drivers_done(void)
1769{
1770 fw_devlink_drv_reg_done = true;
1771 device_links_write_lock();
1772 class_for_each_device(&devlink_class, NULL, NULL,
1773 fw_devlink_no_driver);
1774 device_links_write_unlock();
1775}
1776
1777static int fw_devlink_dev_sync_state(struct device *dev, void *data)
1778{
1779 struct device_link *link = to_devlink(dev);
1780 struct device *sup = link->supplier;
1781
1782 if (!(link->flags & DL_FLAG_MANAGED) ||
1783 link->status == DL_STATE_ACTIVE || sup->state_synced ||
1784 !dev_has_sync_state(sup))
1785 return 0;
1786
1787 if (fw_devlink_sync_state == FW_DEVLINK_SYNC_STATE_STRICT) {
1788 dev_warn(sup, "sync_state() pending due to %s\n",
1789 dev_name(link->consumer));
1790 return 0;
1791 }
1792
1793 if (!list_empty(&sup->links.defer_sync))
1794 return 0;
1795
1796 dev_warn(sup, "Timed out. Forcing sync_state()\n");
1797 sup->state_synced = true;
1798 get_device(sup);
1799 list_add_tail(&sup->links.defer_sync, data);
1800
1801 return 0;
1802}
1803
1804void fw_devlink_probing_done(void)
1805{
1806 LIST_HEAD(sync_list);
1807
1808 device_links_write_lock();
1809 class_for_each_device(&devlink_class, NULL, &sync_list,
1810 fw_devlink_dev_sync_state);
1811 device_links_write_unlock();
1812 device_links_flush_sync_list(&sync_list, NULL);
1813}
1814
1815/**
1816 * wait_for_init_devices_probe - Try to probe any device needed for init
1817 *
1818 * Some devices might need to be probed and bound successfully before the kernel
1819 * boot sequence can finish and move on to init/userspace. For example, a
1820 * network interface might need to be bound to be able to mount a NFS rootfs.
1821 *
1822 * With fw_devlink=on by default, some of these devices might be blocked from
1823 * probing because they are waiting on a optional supplier that doesn't have a
1824 * driver. While fw_devlink will eventually identify such devices and unblock
1825 * the probing automatically, it might be too late by the time it unblocks the
1826 * probing of devices. For example, the IP4 autoconfig might timeout before
1827 * fw_devlink unblocks probing of the network interface.
1828 *
1829 * This function is available to temporarily try and probe all devices that have
1830 * a driver even if some of their suppliers haven't been added or don't have
1831 * drivers.
1832 *
1833 * The drivers can then decide which of the suppliers are optional vs mandatory
1834 * and probe the device if possible. By the time this function returns, all such
1835 * "best effort" probes are guaranteed to be completed. If a device successfully
1836 * probes in this mode, we delete all fw_devlink discovered dependencies of that
1837 * device where the supplier hasn't yet probed successfully because they have to
1838 * be optional dependencies.
1839 *
1840 * Any devices that didn't successfully probe go back to being treated as if
1841 * this function was never called.
1842 *
1843 * This also means that some devices that aren't needed for init and could have
1844 * waited for their optional supplier to probe (when the supplier's module is
1845 * loaded later on) would end up probing prematurely with limited functionality.
1846 * So call this function only when boot would fail without it.
1847 */
1848void __init wait_for_init_devices_probe(void)
1849{
1850 if (!fw_devlink_flags || fw_devlink_is_permissive())
1851 return;
1852
1853 /*
1854 * Wait for all ongoing probes to finish so that the "best effort" is
1855 * only applied to devices that can't probe otherwise.
1856 */
1857 wait_for_device_probe();
1858
1859 pr_info("Trying to probe devices needed for running init ...\n");
1860 fw_devlink_best_effort = true;
1861 driver_deferred_probe_trigger();
1862
1863 /*
1864 * Wait for all "best effort" probes to finish before going back to
1865 * normal enforcement.
1866 */
1867 wait_for_device_probe();
1868 fw_devlink_best_effort = false;
1869}
1870
1871static void fw_devlink_unblock_consumers(struct device *dev)
1872{
1873 struct device_link *link;
1874
1875 if (!fw_devlink_flags || fw_devlink_is_permissive())
1876 return;
1877
1878 device_links_write_lock();
1879 list_for_each_entry(link, &dev->links.consumers, s_node)
1880 fw_devlink_relax_link(link);
1881 device_links_write_unlock();
1882}
1883
1884#define get_dev_from_fwnode(fwnode) get_device((fwnode)->dev)
1885
1886static bool fwnode_init_without_drv(struct fwnode_handle *fwnode)
1887{
1888 struct device *dev;
1889 bool ret;
1890
1891 if (!(fwnode->flags & FWNODE_FLAG_INITIALIZED))
1892 return false;
1893
1894 dev = get_dev_from_fwnode(fwnode);
1895 ret = !dev || dev->links.status == DL_DEV_NO_DRIVER;
1896 put_device(dev);
1897
1898 return ret;
1899}
1900
1901static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
1902{
1903 struct fwnode_handle *parent;
1904
1905 fwnode_for_each_parent_node(fwnode, parent) {
1906 if (fwnode_init_without_drv(parent)) {
1907 fwnode_handle_put(parent);
1908 return true;
1909 }
1910 }
1911
1912 return false;
1913}
1914
1915/**
1916 * fwnode_is_ancestor_of - Test if @ancestor is ancestor of @child
1917 * @ancestor: Firmware which is tested for being an ancestor
1918 * @child: Firmware which is tested for being the child
1919 *
1920 * A node is considered an ancestor of itself too.
1921 *
1922 * Return: true if @ancestor is an ancestor of @child. Otherwise, returns false.
1923 */
1924static bool fwnode_is_ancestor_of(const struct fwnode_handle *ancestor,
1925 const struct fwnode_handle *child)
1926{
1927 struct fwnode_handle *parent;
1928
1929 if (IS_ERR_OR_NULL(ancestor))
1930 return false;
1931
1932 if (child == ancestor)
1933 return true;
1934
1935 fwnode_for_each_parent_node(child, parent) {
1936 if (parent == ancestor) {
1937 fwnode_handle_put(parent);
1938 return true;
1939 }
1940 }
1941 return false;
1942}
1943
1944/**
1945 * fwnode_get_next_parent_dev - Find device of closest ancestor fwnode
1946 * @fwnode: firmware node
1947 *
1948 * Given a firmware node (@fwnode), this function finds its closest ancestor
1949 * firmware node that has a corresponding struct device and returns that struct
1950 * device.
1951 *
1952 * The caller is responsible for calling put_device() on the returned device
1953 * pointer.
1954 *
1955 * Return: a pointer to the device of the @fwnode's closest ancestor.
1956 */
1957static struct device *fwnode_get_next_parent_dev(const struct fwnode_handle *fwnode)
1958{
1959 struct fwnode_handle *parent;
1960 struct device *dev;
1961
1962 fwnode_for_each_parent_node(fwnode, parent) {
1963 dev = get_dev_from_fwnode(parent);
1964 if (dev) {
1965 fwnode_handle_put(parent);
1966 return dev;
1967 }
1968 }
1969 return NULL;
1970}
1971
1972/**
1973 * __fw_devlink_relax_cycles - Relax and mark dependency cycles.
1974 * @con_handle: Potential consumer device fwnode.
1975 * @sup_handle: Potential supplier's fwnode.
1976 *
1977 * Needs to be called with fwnode_lock and device link lock held.
1978 *
1979 * Check if @sup_handle or any of its ancestors or suppliers direct/indirectly
1980 * depend on @con. This function can detect multiple cyles between @sup_handle
1981 * and @con. When such dependency cycles are found, convert all device links
1982 * created solely by fw_devlink into SYNC_STATE_ONLY device links. Also, mark
1983 * all fwnode links in the cycle with FWLINK_FLAG_CYCLE so that when they are
1984 * converted into a device link in the future, they are created as
1985 * SYNC_STATE_ONLY device links. This is the equivalent of doing
1986 * fw_devlink=permissive just between the devices in the cycle. We need to do
1987 * this because, at this point, fw_devlink can't tell which of these
1988 * dependencies is not a real dependency.
1989 *
1990 * Return true if one or more cycles were found. Otherwise, return false.
1991 */
1992static bool __fw_devlink_relax_cycles(struct fwnode_handle *con_handle,
1993 struct fwnode_handle *sup_handle)
1994{
1995 struct device *sup_dev = NULL, *par_dev = NULL, *con_dev = NULL;
1996 struct fwnode_link *link;
1997 struct device_link *dev_link;
1998 bool ret = false;
1999
2000 if (!sup_handle)
2001 return false;
2002
2003 /*
2004 * We aren't trying to find all cycles. Just a cycle between con and
2005 * sup_handle.
2006 */
2007 if (sup_handle->flags & FWNODE_FLAG_VISITED)
2008 return false;
2009
2010 sup_handle->flags |= FWNODE_FLAG_VISITED;
2011
2012 /* Termination condition. */
2013 if (sup_handle == con_handle) {
2014 pr_debug("----- cycle: start -----\n");
2015 ret = true;
2016 goto out;
2017 }
2018
2019 sup_dev = get_dev_from_fwnode(sup_handle);
2020 con_dev = get_dev_from_fwnode(con_handle);
2021 /*
2022 * If sup_dev is bound to a driver and @con hasn't started binding to a
2023 * driver, sup_dev can't be a consumer of @con. So, no need to check
2024 * further.
2025 */
2026 if (sup_dev && sup_dev->links.status == DL_DEV_DRIVER_BOUND &&
2027 con_dev && con_dev->links.status == DL_DEV_NO_DRIVER) {
2028 ret = false;
2029 goto out;
2030 }
2031
2032 list_for_each_entry(link, &sup_handle->suppliers, c_hook) {
2033 if (link->flags & FWLINK_FLAG_IGNORE)
2034 continue;
2035
2036 if (__fw_devlink_relax_cycles(con_handle, link->supplier)) {
2037 __fwnode_link_cycle(link);
2038 ret = true;
2039 }
2040 }
2041
2042 /*
2043 * Give priority to device parent over fwnode parent to account for any
2044 * quirks in how fwnodes are converted to devices.
2045 */
2046 if (sup_dev)
2047 par_dev = get_device(sup_dev->parent);
2048 else
2049 par_dev = fwnode_get_next_parent_dev(sup_handle);
2050
2051 if (par_dev && __fw_devlink_relax_cycles(con_handle, par_dev->fwnode)) {
2052 pr_debug("%pfwf: cycle: child of %pfwf\n", sup_handle,
2053 par_dev->fwnode);
2054 ret = true;
2055 }
2056
2057 if (!sup_dev)
2058 goto out;
2059
2060 list_for_each_entry(dev_link, &sup_dev->links.suppliers, c_node) {
2061 /*
2062 * Ignore a SYNC_STATE_ONLY flag only if it wasn't marked as
2063 * such due to a cycle.
2064 */
2065 if (device_link_flag_is_sync_state_only(dev_link->flags) &&
2066 !(dev_link->flags & DL_FLAG_CYCLE))
2067 continue;
2068
2069 if (__fw_devlink_relax_cycles(con_handle,
2070 dev_link->supplier->fwnode)) {
2071 pr_debug("%pfwf: cycle: depends on %pfwf\n", sup_handle,
2072 dev_link->supplier->fwnode);
2073 fw_devlink_relax_link(dev_link);
2074 dev_link->flags |= DL_FLAG_CYCLE;
2075 ret = true;
2076 }
2077 }
2078
2079out:
2080 sup_handle->flags &= ~FWNODE_FLAG_VISITED;
2081 put_device(sup_dev);
2082 put_device(con_dev);
2083 put_device(par_dev);
2084 return ret;
2085}
2086
2087/**
2088 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
2089 * @con: consumer device for the device link
2090 * @sup_handle: fwnode handle of supplier
2091 * @link: fwnode link that's being converted to a device link
2092 *
2093 * This function will try to create a device link between the consumer device
2094 * @con and the supplier device represented by @sup_handle.
2095 *
2096 * The supplier has to be provided as a fwnode because incorrect cycles in
2097 * fwnode links can sometimes cause the supplier device to never be created.
2098 * This function detects such cases and returns an error if it cannot create a
2099 * device link from the consumer to a missing supplier.
2100 *
2101 * Returns,
2102 * 0 on successfully creating a device link
2103 * -EINVAL if the device link cannot be created as expected
2104 * -EAGAIN if the device link cannot be created right now, but it may be
2105 * possible to do that in the future
2106 */
2107static int fw_devlink_create_devlink(struct device *con,
2108 struct fwnode_handle *sup_handle,
2109 struct fwnode_link *link)
2110{
2111 struct device *sup_dev;
2112 int ret = 0;
2113 u32 flags;
2114
2115 if (link->flags & FWLINK_FLAG_IGNORE)
2116 return 0;
2117
2118 /*
2119 * In some cases, a device P might also be a supplier to its child node
2120 * C. However, this would defer the probe of C until the probe of P
2121 * completes successfully. This is perfectly fine in the device driver
2122 * model. device_add() doesn't guarantee probe completion of the device
2123 * by the time it returns.
2124 *
2125 * However, there are a few drivers that assume C will finish probing
2126 * as soon as it's added and before P finishes probing. So, we provide
2127 * a flag to let fw_devlink know not to delay the probe of C until the
2128 * probe of P completes successfully.
2129 *
2130 * When such a flag is set, we can't create device links where P is the
2131 * supplier of C as that would delay the probe of C.
2132 */
2133 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
2134 fwnode_is_ancestor_of(sup_handle, con->fwnode))
2135 return -EINVAL;
2136
2137 /*
2138 * Don't try to optimize by not calling the cycle detection logic under
2139 * certain conditions. There's always some corner case that won't get
2140 * detected.
2141 */
2142 device_links_write_lock();
2143 if (__fw_devlink_relax_cycles(link->consumer, sup_handle)) {
2144 __fwnode_link_cycle(link);
2145 pr_debug("----- cycle: end -----\n");
2146 pr_info("%pfwf: Fixed dependency cycle(s) with %pfwf\n",
2147 link->consumer, sup_handle);
2148 }
2149 device_links_write_unlock();
2150
2151 if (con->fwnode == link->consumer)
2152 flags = fw_devlink_get_flags(link->flags);
2153 else
2154 flags = FW_DEVLINK_FLAGS_PERMISSIVE;
2155
2156 if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE)
2157 sup_dev = fwnode_get_next_parent_dev(sup_handle);
2158 else
2159 sup_dev = get_dev_from_fwnode(sup_handle);
2160
2161 if (sup_dev) {
2162 /*
2163 * If it's one of those drivers that don't actually bind to
2164 * their device using driver core, then don't wait on this
2165 * supplier device indefinitely.
2166 */
2167 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
2168 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
2169 dev_dbg(con,
2170 "Not linking %pfwf - dev might never probe\n",
2171 sup_handle);
2172 ret = -EINVAL;
2173 goto out;
2174 }
2175
2176 if (con != sup_dev && !device_link_add(con, sup_dev, flags)) {
2177 dev_err(con, "Failed to create device link (0x%x) with supplier %s for %pfwf\n",
2178 flags, dev_name(sup_dev), link->consumer);
2179 ret = -EINVAL;
2180 }
2181
2182 goto out;
2183 }
2184
2185 /*
2186 * Supplier or supplier's ancestor already initialized without a struct
2187 * device or being probed by a driver.
2188 */
2189 if (fwnode_init_without_drv(sup_handle) ||
2190 fwnode_ancestor_init_without_drv(sup_handle)) {
2191 dev_dbg(con, "Not linking %pfwf - might never become dev\n",
2192 sup_handle);
2193 return -EINVAL;
2194 }
2195
2196 ret = -EAGAIN;
2197out:
2198 put_device(sup_dev);
2199 return ret;
2200}
2201
2202/**
2203 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
2204 * @dev: Device that needs to be linked to its consumers
2205 *
2206 * This function looks at all the consumer fwnodes of @dev and creates device
2207 * links between the consumer device and @dev (supplier).
2208 *
2209 * If the consumer device has not been added yet, then this function creates a
2210 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
2211 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
2212 * sync_state() callback before the real consumer device gets to be added and
2213 * then probed.
2214 *
2215 * Once device links are created from the real consumer to @dev (supplier), the
2216 * fwnode links are deleted.
2217 */
2218static void __fw_devlink_link_to_consumers(struct device *dev)
2219{
2220 struct fwnode_handle *fwnode = dev->fwnode;
2221 struct fwnode_link *link, *tmp;
2222
2223 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
2224 struct device *con_dev;
2225 bool own_link = true;
2226 int ret;
2227
2228 con_dev = get_dev_from_fwnode(link->consumer);
2229 /*
2230 * If consumer device is not available yet, make a "proxy"
2231 * SYNC_STATE_ONLY link from the consumer's parent device to
2232 * the supplier device. This is necessary to make sure the
2233 * supplier doesn't get a sync_state() callback before the real
2234 * consumer can create a device link to the supplier.
2235 *
2236 * This proxy link step is needed to handle the case where the
2237 * consumer's parent device is added before the supplier.
2238 */
2239 if (!con_dev) {
2240 con_dev = fwnode_get_next_parent_dev(link->consumer);
2241 /*
2242 * However, if the consumer's parent device is also the
2243 * parent of the supplier, don't create a
2244 * consumer-supplier link from the parent to its child
2245 * device. Such a dependency is impossible.
2246 */
2247 if (con_dev &&
2248 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
2249 put_device(con_dev);
2250 con_dev = NULL;
2251 } else {
2252 own_link = false;
2253 }
2254 }
2255
2256 if (!con_dev)
2257 continue;
2258
2259 ret = fw_devlink_create_devlink(con_dev, fwnode, link);
2260 put_device(con_dev);
2261 if (!own_link || ret == -EAGAIN)
2262 continue;
2263
2264 __fwnode_link_del(link);
2265 }
2266}
2267
2268/**
2269 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
2270 * @dev: The consumer device that needs to be linked to its suppliers
2271 * @fwnode: Root of the fwnode tree that is used to create device links
2272 *
2273 * This function looks at all the supplier fwnodes of fwnode tree rooted at
2274 * @fwnode and creates device links between @dev (consumer) and all the
2275 * supplier devices of the entire fwnode tree at @fwnode.
2276 *
2277 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
2278 * and the real suppliers of @dev. Once these device links are created, the
2279 * fwnode links are deleted.
2280 *
2281 * In addition, it also looks at all the suppliers of the entire fwnode tree
2282 * because some of the child devices of @dev that have not been added yet
2283 * (because @dev hasn't probed) might already have their suppliers added to
2284 * driver core. So, this function creates SYNC_STATE_ONLY device links between
2285 * @dev (consumer) and these suppliers to make sure they don't execute their
2286 * sync_state() callbacks before these child devices have a chance to create
2287 * their device links. The fwnode links that correspond to the child devices
2288 * aren't delete because they are needed later to create the device links
2289 * between the real consumer and supplier devices.
2290 */
2291static void __fw_devlink_link_to_suppliers(struct device *dev,
2292 struct fwnode_handle *fwnode)
2293{
2294 bool own_link = (dev->fwnode == fwnode);
2295 struct fwnode_link *link, *tmp;
2296 struct fwnode_handle *child = NULL;
2297
2298 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
2299 int ret;
2300 struct fwnode_handle *sup = link->supplier;
2301
2302 ret = fw_devlink_create_devlink(dev, sup, link);
2303 if (!own_link || ret == -EAGAIN)
2304 continue;
2305
2306 __fwnode_link_del(link);
2307 }
2308
2309 /*
2310 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
2311 * all the descendants. This proxy link step is needed to handle the
2312 * case where the supplier is added before the consumer's parent device
2313 * (@dev).
2314 */
2315 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
2316 __fw_devlink_link_to_suppliers(dev, child);
2317}
2318
2319static void fw_devlink_link_device(struct device *dev)
2320{
2321 struct fwnode_handle *fwnode = dev->fwnode;
2322
2323 if (!fw_devlink_flags)
2324 return;
2325
2326 fw_devlink_parse_fwtree(fwnode);
2327
2328 guard(mutex)(&fwnode_link_lock);
2329
2330 __fw_devlink_link_to_consumers(dev);
2331 __fw_devlink_link_to_suppliers(dev, fwnode);
2332}
2333
2334/* Device links support end. */
2335
2336static struct kobject *dev_kobj;
2337
2338/* /sys/dev/char */
2339static struct kobject *sysfs_dev_char_kobj;
2340
2341/* /sys/dev/block */
2342static struct kobject *sysfs_dev_block_kobj;
2343
2344static DEFINE_MUTEX(device_hotplug_lock);
2345
2346void lock_device_hotplug(void)
2347{
2348 mutex_lock(&device_hotplug_lock);
2349}
2350
2351void unlock_device_hotplug(void)
2352{
2353 mutex_unlock(&device_hotplug_lock);
2354}
2355
2356int lock_device_hotplug_sysfs(void)
2357{
2358 if (mutex_trylock(&device_hotplug_lock))
2359 return 0;
2360
2361 /* Avoid busy looping (5 ms of sleep should do). */
2362 msleep(5);
2363 return restart_syscall();
2364}
2365
2366#ifdef CONFIG_BLOCK
2367static inline int device_is_not_partition(struct device *dev)
2368{
2369 return !(dev->type == &part_type);
2370}
2371#else
2372static inline int device_is_not_partition(struct device *dev)
2373{
2374 return 1;
2375}
2376#endif
2377
2378static void device_platform_notify(struct device *dev)
2379{
2380 acpi_device_notify(dev);
2381
2382 software_node_notify(dev);
2383}
2384
2385static void device_platform_notify_remove(struct device *dev)
2386{
2387 software_node_notify_remove(dev);
2388
2389 acpi_device_notify_remove(dev);
2390}
2391
2392/**
2393 * dev_driver_string - Return a device's driver name, if at all possible
2394 * @dev: struct device to get the name of
2395 *
2396 * Will return the device's driver's name if it is bound to a device. If
2397 * the device is not bound to a driver, it will return the name of the bus
2398 * it is attached to. If it is not attached to a bus either, an empty
2399 * string will be returned.
2400 */
2401const char *dev_driver_string(const struct device *dev)
2402{
2403 struct device_driver *drv;
2404
2405 /* dev->driver can change to NULL underneath us because of unbinding,
2406 * so be careful about accessing it. dev->bus and dev->class should
2407 * never change once they are set, so they don't need special care.
2408 */
2409 drv = READ_ONCE(dev->driver);
2410 return drv ? drv->name : dev_bus_name(dev);
2411}
2412EXPORT_SYMBOL(dev_driver_string);
2413
2414#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2415
2416static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2417 char *buf)
2418{
2419 struct device_attribute *dev_attr = to_dev_attr(attr);
2420 struct device *dev = kobj_to_dev(kobj);
2421 ssize_t ret = -EIO;
2422
2423 if (dev_attr->show)
2424 ret = dev_attr->show(dev, dev_attr, buf);
2425 if (ret >= (ssize_t)PAGE_SIZE) {
2426 printk("dev_attr_show: %pS returned bad count\n",
2427 dev_attr->show);
2428 }
2429 return ret;
2430}
2431
2432static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2433 const char *buf, size_t count)
2434{
2435 struct device_attribute *dev_attr = to_dev_attr(attr);
2436 struct device *dev = kobj_to_dev(kobj);
2437 ssize_t ret = -EIO;
2438
2439 if (dev_attr->store)
2440 ret = dev_attr->store(dev, dev_attr, buf, count);
2441 return ret;
2442}
2443
2444static const struct sysfs_ops dev_sysfs_ops = {
2445 .show = dev_attr_show,
2446 .store = dev_attr_store,
2447};
2448
2449#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2450
2451ssize_t device_store_ulong(struct device *dev,
2452 struct device_attribute *attr,
2453 const char *buf, size_t size)
2454{
2455 struct dev_ext_attribute *ea = to_ext_attr(attr);
2456 int ret;
2457 unsigned long new;
2458
2459 ret = kstrtoul(buf, 0, &new);
2460 if (ret)
2461 return ret;
2462 *(unsigned long *)(ea->var) = new;
2463 /* Always return full write size even if we didn't consume all */
2464 return size;
2465}
2466EXPORT_SYMBOL_GPL(device_store_ulong);
2467
2468ssize_t device_show_ulong(struct device *dev,
2469 struct device_attribute *attr,
2470 char *buf)
2471{
2472 struct dev_ext_attribute *ea = to_ext_attr(attr);
2473 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2474}
2475EXPORT_SYMBOL_GPL(device_show_ulong);
2476
2477ssize_t device_store_int(struct device *dev,
2478 struct device_attribute *attr,
2479 const char *buf, size_t size)
2480{
2481 struct dev_ext_attribute *ea = to_ext_attr(attr);
2482 int ret;
2483 long new;
2484
2485 ret = kstrtol(buf, 0, &new);
2486 if (ret)
2487 return ret;
2488
2489 if (new > INT_MAX || new < INT_MIN)
2490 return -EINVAL;
2491 *(int *)(ea->var) = new;
2492 /* Always return full write size even if we didn't consume all */
2493 return size;
2494}
2495EXPORT_SYMBOL_GPL(device_store_int);
2496
2497ssize_t device_show_int(struct device *dev,
2498 struct device_attribute *attr,
2499 char *buf)
2500{
2501 struct dev_ext_attribute *ea = to_ext_attr(attr);
2502
2503 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2504}
2505EXPORT_SYMBOL_GPL(device_show_int);
2506
2507ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2508 const char *buf, size_t size)
2509{
2510 struct dev_ext_attribute *ea = to_ext_attr(attr);
2511
2512 if (kstrtobool(buf, ea->var) < 0)
2513 return -EINVAL;
2514
2515 return size;
2516}
2517EXPORT_SYMBOL_GPL(device_store_bool);
2518
2519ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2520 char *buf)
2521{
2522 struct dev_ext_attribute *ea = to_ext_attr(attr);
2523
2524 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2525}
2526EXPORT_SYMBOL_GPL(device_show_bool);
2527
2528ssize_t device_show_string(struct device *dev,
2529 struct device_attribute *attr, char *buf)
2530{
2531 struct dev_ext_attribute *ea = to_ext_attr(attr);
2532
2533 return sysfs_emit(buf, "%s\n", (char *)ea->var);
2534}
2535EXPORT_SYMBOL_GPL(device_show_string);
2536
2537/**
2538 * device_release - free device structure.
2539 * @kobj: device's kobject.
2540 *
2541 * This is called once the reference count for the object
2542 * reaches 0. We forward the call to the device's release
2543 * method, which should handle actually freeing the structure.
2544 */
2545static void device_release(struct kobject *kobj)
2546{
2547 struct device *dev = kobj_to_dev(kobj);
2548 struct device_private *p = dev->p;
2549
2550 /*
2551 * Some platform devices are driven without driver attached
2552 * and managed resources may have been acquired. Make sure
2553 * all resources are released.
2554 *
2555 * Drivers still can add resources into device after device
2556 * is deleted but alive, so release devres here to avoid
2557 * possible memory leak.
2558 */
2559 devres_release_all(dev);
2560
2561 kfree(dev->dma_range_map);
2562
2563 if (dev->release)
2564 dev->release(dev);
2565 else if (dev->type && dev->type->release)
2566 dev->type->release(dev);
2567 else if (dev->class && dev->class->dev_release)
2568 dev->class->dev_release(dev);
2569 else
2570 WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
2571 dev_name(dev));
2572 kfree(p);
2573}
2574
2575static const void *device_namespace(const struct kobject *kobj)
2576{
2577 const struct device *dev = kobj_to_dev(kobj);
2578 const void *ns = NULL;
2579
2580 if (dev->class && dev->class->namespace)
2581 ns = dev->class->namespace(dev);
2582
2583 return ns;
2584}
2585
2586static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2587{
2588 const struct device *dev = kobj_to_dev(kobj);
2589
2590 if (dev->class && dev->class->get_ownership)
2591 dev->class->get_ownership(dev, uid, gid);
2592}
2593
2594static const struct kobj_type device_ktype = {
2595 .release = device_release,
2596 .sysfs_ops = &dev_sysfs_ops,
2597 .namespace = device_namespace,
2598 .get_ownership = device_get_ownership,
2599};
2600
2601
2602static int dev_uevent_filter(const struct kobject *kobj)
2603{
2604 const struct kobj_type *ktype = get_ktype(kobj);
2605
2606 if (ktype == &device_ktype) {
2607 const struct device *dev = kobj_to_dev(kobj);
2608 if (dev->bus)
2609 return 1;
2610 if (dev->class)
2611 return 1;
2612 }
2613 return 0;
2614}
2615
2616static const char *dev_uevent_name(const struct kobject *kobj)
2617{
2618 const struct device *dev = kobj_to_dev(kobj);
2619
2620 if (dev->bus)
2621 return dev->bus->name;
2622 if (dev->class)
2623 return dev->class->name;
2624 return NULL;
2625}
2626
2627static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
2628{
2629 const struct device *dev = kobj_to_dev(kobj);
2630 int retval = 0;
2631
2632 /* add device node properties if present */
2633 if (MAJOR(dev->devt)) {
2634 const char *tmp;
2635 const char *name;
2636 umode_t mode = 0;
2637 kuid_t uid = GLOBAL_ROOT_UID;
2638 kgid_t gid = GLOBAL_ROOT_GID;
2639
2640 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2641 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2642 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2643 if (name) {
2644 add_uevent_var(env, "DEVNAME=%s", name);
2645 if (mode)
2646 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2647 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2648 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2649 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2650 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2651 kfree(tmp);
2652 }
2653 }
2654
2655 if (dev->type && dev->type->name)
2656 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2657
2658 if (dev->driver)
2659 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2660
2661 /* Add common DT information about the device */
2662 of_device_uevent(dev, env);
2663
2664 /* have the bus specific function add its stuff */
2665 if (dev->bus && dev->bus->uevent) {
2666 retval = dev->bus->uevent(dev, env);
2667 if (retval)
2668 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2669 dev_name(dev), __func__, retval);
2670 }
2671
2672 /* have the class specific function add its stuff */
2673 if (dev->class && dev->class->dev_uevent) {
2674 retval = dev->class->dev_uevent(dev, env);
2675 if (retval)
2676 pr_debug("device: '%s': %s: class uevent() "
2677 "returned %d\n", dev_name(dev),
2678 __func__, retval);
2679 }
2680
2681 /* have the device type specific function add its stuff */
2682 if (dev->type && dev->type->uevent) {
2683 retval = dev->type->uevent(dev, env);
2684 if (retval)
2685 pr_debug("device: '%s': %s: dev_type uevent() "
2686 "returned %d\n", dev_name(dev),
2687 __func__, retval);
2688 }
2689
2690 return retval;
2691}
2692
2693static const struct kset_uevent_ops device_uevent_ops = {
2694 .filter = dev_uevent_filter,
2695 .name = dev_uevent_name,
2696 .uevent = dev_uevent,
2697};
2698
2699static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2700 char *buf)
2701{
2702 struct kobject *top_kobj;
2703 struct kset *kset;
2704 struct kobj_uevent_env *env = NULL;
2705 int i;
2706 int len = 0;
2707 int retval;
2708
2709 /* search the kset, the device belongs to */
2710 top_kobj = &dev->kobj;
2711 while (!top_kobj->kset && top_kobj->parent)
2712 top_kobj = top_kobj->parent;
2713 if (!top_kobj->kset)
2714 goto out;
2715
2716 kset = top_kobj->kset;
2717 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2718 goto out;
2719
2720 /* respect filter */
2721 if (kset->uevent_ops && kset->uevent_ops->filter)
2722 if (!kset->uevent_ops->filter(&dev->kobj))
2723 goto out;
2724
2725 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2726 if (!env)
2727 return -ENOMEM;
2728
2729 /* Synchronize with really_probe() */
2730 device_lock(dev);
2731 /* let the kset specific function add its keys */
2732 retval = kset->uevent_ops->uevent(&dev->kobj, env);
2733 device_unlock(dev);
2734 if (retval)
2735 goto out;
2736
2737 /* copy keys to file */
2738 for (i = 0; i < env->envp_idx; i++)
2739 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2740out:
2741 kfree(env);
2742 return len;
2743}
2744
2745static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2746 const char *buf, size_t count)
2747{
2748 int rc;
2749
2750 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2751
2752 if (rc) {
2753 dev_err(dev, "uevent: failed to send synthetic uevent: %d\n", rc);
2754 return rc;
2755 }
2756
2757 return count;
2758}
2759static DEVICE_ATTR_RW(uevent);
2760
2761static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2762 char *buf)
2763{
2764 bool val;
2765
2766 device_lock(dev);
2767 val = !dev->offline;
2768 device_unlock(dev);
2769 return sysfs_emit(buf, "%u\n", val);
2770}
2771
2772static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2773 const char *buf, size_t count)
2774{
2775 bool val;
2776 int ret;
2777
2778 ret = kstrtobool(buf, &val);
2779 if (ret < 0)
2780 return ret;
2781
2782 ret = lock_device_hotplug_sysfs();
2783 if (ret)
2784 return ret;
2785
2786 ret = val ? device_online(dev) : device_offline(dev);
2787 unlock_device_hotplug();
2788 return ret < 0 ? ret : count;
2789}
2790static DEVICE_ATTR_RW(online);
2791
2792static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2793 char *buf)
2794{
2795 const char *loc;
2796
2797 switch (dev->removable) {
2798 case DEVICE_REMOVABLE:
2799 loc = "removable";
2800 break;
2801 case DEVICE_FIXED:
2802 loc = "fixed";
2803 break;
2804 default:
2805 loc = "unknown";
2806 }
2807 return sysfs_emit(buf, "%s\n", loc);
2808}
2809static DEVICE_ATTR_RO(removable);
2810
2811int device_add_groups(struct device *dev, const struct attribute_group **groups)
2812{
2813 return sysfs_create_groups(&dev->kobj, groups);
2814}
2815EXPORT_SYMBOL_GPL(device_add_groups);
2816
2817void device_remove_groups(struct device *dev,
2818 const struct attribute_group **groups)
2819{
2820 sysfs_remove_groups(&dev->kobj, groups);
2821}
2822EXPORT_SYMBOL_GPL(device_remove_groups);
2823
2824union device_attr_group_devres {
2825 const struct attribute_group *group;
2826 const struct attribute_group **groups;
2827};
2828
2829static void devm_attr_group_remove(struct device *dev, void *res)
2830{
2831 union device_attr_group_devres *devres = res;
2832 const struct attribute_group *group = devres->group;
2833
2834 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2835 sysfs_remove_group(&dev->kobj, group);
2836}
2837
2838/**
2839 * devm_device_add_group - given a device, create a managed attribute group
2840 * @dev: The device to create the group for
2841 * @grp: The attribute group to create
2842 *
2843 * This function creates a group for the first time. It will explicitly
2844 * warn and error if any of the attribute files being created already exist.
2845 *
2846 * Returns 0 on success or error code on failure.
2847 */
2848int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2849{
2850 union device_attr_group_devres *devres;
2851 int error;
2852
2853 devres = devres_alloc(devm_attr_group_remove,
2854 sizeof(*devres), GFP_KERNEL);
2855 if (!devres)
2856 return -ENOMEM;
2857
2858 error = sysfs_create_group(&dev->kobj, grp);
2859 if (error) {
2860 devres_free(devres);
2861 return error;
2862 }
2863
2864 devres->group = grp;
2865 devres_add(dev, devres);
2866 return 0;
2867}
2868EXPORT_SYMBOL_GPL(devm_device_add_group);
2869
2870static int device_add_attrs(struct device *dev)
2871{
2872 const struct class *class = dev->class;
2873 const struct device_type *type = dev->type;
2874 int error;
2875
2876 if (class) {
2877 error = device_add_groups(dev, class->dev_groups);
2878 if (error)
2879 return error;
2880 }
2881
2882 if (type) {
2883 error = device_add_groups(dev, type->groups);
2884 if (error)
2885 goto err_remove_class_groups;
2886 }
2887
2888 error = device_add_groups(dev, dev->groups);
2889 if (error)
2890 goto err_remove_type_groups;
2891
2892 if (device_supports_offline(dev) && !dev->offline_disabled) {
2893 error = device_create_file(dev, &dev_attr_online);
2894 if (error)
2895 goto err_remove_dev_groups;
2896 }
2897
2898 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2899 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2900 if (error)
2901 goto err_remove_dev_online;
2902 }
2903
2904 if (dev_removable_is_valid(dev)) {
2905 error = device_create_file(dev, &dev_attr_removable);
2906 if (error)
2907 goto err_remove_dev_waiting_for_supplier;
2908 }
2909
2910 if (dev_add_physical_location(dev)) {
2911 error = device_add_group(dev,
2912 &dev_attr_physical_location_group);
2913 if (error)
2914 goto err_remove_dev_removable;
2915 }
2916
2917 return 0;
2918
2919 err_remove_dev_removable:
2920 device_remove_file(dev, &dev_attr_removable);
2921 err_remove_dev_waiting_for_supplier:
2922 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2923 err_remove_dev_online:
2924 device_remove_file(dev, &dev_attr_online);
2925 err_remove_dev_groups:
2926 device_remove_groups(dev, dev->groups);
2927 err_remove_type_groups:
2928 if (type)
2929 device_remove_groups(dev, type->groups);
2930 err_remove_class_groups:
2931 if (class)
2932 device_remove_groups(dev, class->dev_groups);
2933
2934 return error;
2935}
2936
2937static void device_remove_attrs(struct device *dev)
2938{
2939 const struct class *class = dev->class;
2940 const struct device_type *type = dev->type;
2941
2942 if (dev->physical_location) {
2943 device_remove_group(dev, &dev_attr_physical_location_group);
2944 kfree(dev->physical_location);
2945 }
2946
2947 device_remove_file(dev, &dev_attr_removable);
2948 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2949 device_remove_file(dev, &dev_attr_online);
2950 device_remove_groups(dev, dev->groups);
2951
2952 if (type)
2953 device_remove_groups(dev, type->groups);
2954
2955 if (class)
2956 device_remove_groups(dev, class->dev_groups);
2957}
2958
2959static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2960 char *buf)
2961{
2962 return print_dev_t(buf, dev->devt);
2963}
2964static DEVICE_ATTR_RO(dev);
2965
2966/* /sys/devices/ */
2967struct kset *devices_kset;
2968
2969/**
2970 * devices_kset_move_before - Move device in the devices_kset's list.
2971 * @deva: Device to move.
2972 * @devb: Device @deva should come before.
2973 */
2974static void devices_kset_move_before(struct device *deva, struct device *devb)
2975{
2976 if (!devices_kset)
2977 return;
2978 pr_debug("devices_kset: Moving %s before %s\n",
2979 dev_name(deva), dev_name(devb));
2980 spin_lock(&devices_kset->list_lock);
2981 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2982 spin_unlock(&devices_kset->list_lock);
2983}
2984
2985/**
2986 * devices_kset_move_after - Move device in the devices_kset's list.
2987 * @deva: Device to move
2988 * @devb: Device @deva should come after.
2989 */
2990static void devices_kset_move_after(struct device *deva, struct device *devb)
2991{
2992 if (!devices_kset)
2993 return;
2994 pr_debug("devices_kset: Moving %s after %s\n",
2995 dev_name(deva), dev_name(devb));
2996 spin_lock(&devices_kset->list_lock);
2997 list_move(&deva->kobj.entry, &devb->kobj.entry);
2998 spin_unlock(&devices_kset->list_lock);
2999}
3000
3001/**
3002 * devices_kset_move_last - move the device to the end of devices_kset's list.
3003 * @dev: device to move
3004 */
3005void devices_kset_move_last(struct device *dev)
3006{
3007 if (!devices_kset)
3008 return;
3009 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
3010 spin_lock(&devices_kset->list_lock);
3011 list_move_tail(&dev->kobj.entry, &devices_kset->list);
3012 spin_unlock(&devices_kset->list_lock);
3013}
3014
3015/**
3016 * device_create_file - create sysfs attribute file for device.
3017 * @dev: device.
3018 * @attr: device attribute descriptor.
3019 */
3020int device_create_file(struct device *dev,
3021 const struct device_attribute *attr)
3022{
3023 int error = 0;
3024
3025 if (dev) {
3026 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
3027 "Attribute %s: write permission without 'store'\n",
3028 attr->attr.name);
3029 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
3030 "Attribute %s: read permission without 'show'\n",
3031 attr->attr.name);
3032 error = sysfs_create_file(&dev->kobj, &attr->attr);
3033 }
3034
3035 return error;
3036}
3037EXPORT_SYMBOL_GPL(device_create_file);
3038
3039/**
3040 * device_remove_file - remove sysfs attribute file.
3041 * @dev: device.
3042 * @attr: device attribute descriptor.
3043 */
3044void device_remove_file(struct device *dev,
3045 const struct device_attribute *attr)
3046{
3047 if (dev)
3048 sysfs_remove_file(&dev->kobj, &attr->attr);
3049}
3050EXPORT_SYMBOL_GPL(device_remove_file);
3051
3052/**
3053 * device_remove_file_self - remove sysfs attribute file from its own method.
3054 * @dev: device.
3055 * @attr: device attribute descriptor.
3056 *
3057 * See kernfs_remove_self() for details.
3058 */
3059bool device_remove_file_self(struct device *dev,
3060 const struct device_attribute *attr)
3061{
3062 if (dev)
3063 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
3064 else
3065 return false;
3066}
3067EXPORT_SYMBOL_GPL(device_remove_file_self);
3068
3069/**
3070 * device_create_bin_file - create sysfs binary attribute file for device.
3071 * @dev: device.
3072 * @attr: device binary attribute descriptor.
3073 */
3074int device_create_bin_file(struct device *dev,
3075 const struct bin_attribute *attr)
3076{
3077 int error = -EINVAL;
3078 if (dev)
3079 error = sysfs_create_bin_file(&dev->kobj, attr);
3080 return error;
3081}
3082EXPORT_SYMBOL_GPL(device_create_bin_file);
3083
3084/**
3085 * device_remove_bin_file - remove sysfs binary attribute file
3086 * @dev: device.
3087 * @attr: device binary attribute descriptor.
3088 */
3089void device_remove_bin_file(struct device *dev,
3090 const struct bin_attribute *attr)
3091{
3092 if (dev)
3093 sysfs_remove_bin_file(&dev->kobj, attr);
3094}
3095EXPORT_SYMBOL_GPL(device_remove_bin_file);
3096
3097static void klist_children_get(struct klist_node *n)
3098{
3099 struct device_private *p = to_device_private_parent(n);
3100 struct device *dev = p->device;
3101
3102 get_device(dev);
3103}
3104
3105static void klist_children_put(struct klist_node *n)
3106{
3107 struct device_private *p = to_device_private_parent(n);
3108 struct device *dev = p->device;
3109
3110 put_device(dev);
3111}
3112
3113/**
3114 * device_initialize - init device structure.
3115 * @dev: device.
3116 *
3117 * This prepares the device for use by other layers by initializing
3118 * its fields.
3119 * It is the first half of device_register(), if called by
3120 * that function, though it can also be called separately, so one
3121 * may use @dev's fields. In particular, get_device()/put_device()
3122 * may be used for reference counting of @dev after calling this
3123 * function.
3124 *
3125 * All fields in @dev must be initialized by the caller to 0, except
3126 * for those explicitly set to some other value. The simplest
3127 * approach is to use kzalloc() to allocate the structure containing
3128 * @dev.
3129 *
3130 * NOTE: Use put_device() to give up your reference instead of freeing
3131 * @dev directly once you have called this function.
3132 */
3133void device_initialize(struct device *dev)
3134{
3135 dev->kobj.kset = devices_kset;
3136 kobject_init(&dev->kobj, &device_ktype);
3137 INIT_LIST_HEAD(&dev->dma_pools);
3138 mutex_init(&dev->mutex);
3139 lockdep_set_novalidate_class(&dev->mutex);
3140 spin_lock_init(&dev->devres_lock);
3141 INIT_LIST_HEAD(&dev->devres_head);
3142 device_pm_init(dev);
3143 set_dev_node(dev, NUMA_NO_NODE);
3144 INIT_LIST_HEAD(&dev->links.consumers);
3145 INIT_LIST_HEAD(&dev->links.suppliers);
3146 INIT_LIST_HEAD(&dev->links.defer_sync);
3147 dev->links.status = DL_DEV_NO_DRIVER;
3148#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
3149 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
3150 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
3151 dev->dma_coherent = dma_default_coherent;
3152#endif
3153 swiotlb_dev_init(dev);
3154}
3155EXPORT_SYMBOL_GPL(device_initialize);
3156
3157struct kobject *virtual_device_parent(void)
3158{
3159 static struct kobject *virtual_dir = NULL;
3160
3161 if (!virtual_dir)
3162 virtual_dir = kobject_create_and_add("virtual",
3163 &devices_kset->kobj);
3164
3165 return virtual_dir;
3166}
3167
3168struct class_dir {
3169 struct kobject kobj;
3170 const struct class *class;
3171};
3172
3173#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
3174
3175static void class_dir_release(struct kobject *kobj)
3176{
3177 struct class_dir *dir = to_class_dir(kobj);
3178 kfree(dir);
3179}
3180
3181static const
3182struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *kobj)
3183{
3184 const struct class_dir *dir = to_class_dir(kobj);
3185 return dir->class->ns_type;
3186}
3187
3188static const struct kobj_type class_dir_ktype = {
3189 .release = class_dir_release,
3190 .sysfs_ops = &kobj_sysfs_ops,
3191 .child_ns_type = class_dir_child_ns_type
3192};
3193
3194static struct kobject *class_dir_create_and_add(struct subsys_private *sp,
3195 struct kobject *parent_kobj)
3196{
3197 struct class_dir *dir;
3198 int retval;
3199
3200 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
3201 if (!dir)
3202 return ERR_PTR(-ENOMEM);
3203
3204 dir->class = sp->class;
3205 kobject_init(&dir->kobj, &class_dir_ktype);
3206
3207 dir->kobj.kset = &sp->glue_dirs;
3208
3209 retval = kobject_add(&dir->kobj, parent_kobj, "%s", sp->class->name);
3210 if (retval < 0) {
3211 kobject_put(&dir->kobj);
3212 return ERR_PTR(retval);
3213 }
3214 return &dir->kobj;
3215}
3216
3217static DEFINE_MUTEX(gdp_mutex);
3218
3219static struct kobject *get_device_parent(struct device *dev,
3220 struct device *parent)
3221{
3222 struct subsys_private *sp = class_to_subsys(dev->class);
3223 struct kobject *kobj = NULL;
3224
3225 if (sp) {
3226 struct kobject *parent_kobj;
3227 struct kobject *k;
3228
3229 /*
3230 * If we have no parent, we live in "virtual".
3231 * Class-devices with a non class-device as parent, live
3232 * in a "glue" directory to prevent namespace collisions.
3233 */
3234 if (parent == NULL)
3235 parent_kobj = virtual_device_parent();
3236 else if (parent->class && !dev->class->ns_type) {
3237 subsys_put(sp);
3238 return &parent->kobj;
3239 } else {
3240 parent_kobj = &parent->kobj;
3241 }
3242
3243 mutex_lock(&gdp_mutex);
3244
3245 /* find our class-directory at the parent and reference it */
3246 spin_lock(&sp->glue_dirs.list_lock);
3247 list_for_each_entry(k, &sp->glue_dirs.list, entry)
3248 if (k->parent == parent_kobj) {
3249 kobj = kobject_get(k);
3250 break;
3251 }
3252 spin_unlock(&sp->glue_dirs.list_lock);
3253 if (kobj) {
3254 mutex_unlock(&gdp_mutex);
3255 subsys_put(sp);
3256 return kobj;
3257 }
3258
3259 /* or create a new class-directory at the parent device */
3260 k = class_dir_create_and_add(sp, parent_kobj);
3261 /* do not emit an uevent for this simple "glue" directory */
3262 mutex_unlock(&gdp_mutex);
3263 subsys_put(sp);
3264 return k;
3265 }
3266
3267 /* subsystems can specify a default root directory for their devices */
3268 if (!parent && dev->bus) {
3269 struct device *dev_root = bus_get_dev_root(dev->bus);
3270
3271 if (dev_root) {
3272 kobj = &dev_root->kobj;
3273 put_device(dev_root);
3274 return kobj;
3275 }
3276 }
3277
3278 if (parent)
3279 return &parent->kobj;
3280 return NULL;
3281}
3282
3283static inline bool live_in_glue_dir(struct kobject *kobj,
3284 struct device *dev)
3285{
3286 struct subsys_private *sp;
3287 bool retval;
3288
3289 if (!kobj || !dev->class)
3290 return false;
3291
3292 sp = class_to_subsys(dev->class);
3293 if (!sp)
3294 return false;
3295
3296 if (kobj->kset == &sp->glue_dirs)
3297 retval = true;
3298 else
3299 retval = false;
3300
3301 subsys_put(sp);
3302 return retval;
3303}
3304
3305static inline struct kobject *get_glue_dir(struct device *dev)
3306{
3307 return dev->kobj.parent;
3308}
3309
3310/**
3311 * kobject_has_children - Returns whether a kobject has children.
3312 * @kobj: the object to test
3313 *
3314 * This will return whether a kobject has other kobjects as children.
3315 *
3316 * It does NOT account for the presence of attribute files, only sub
3317 * directories. It also assumes there is no concurrent addition or
3318 * removal of such children, and thus relies on external locking.
3319 */
3320static inline bool kobject_has_children(struct kobject *kobj)
3321{
3322 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
3323
3324 return kobj->sd && kobj->sd->dir.subdirs;
3325}
3326
3327/*
3328 * make sure cleaning up dir as the last step, we need to make
3329 * sure .release handler of kobject is run with holding the
3330 * global lock
3331 */
3332static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3333{
3334 unsigned int ref;
3335
3336 /* see if we live in a "glue" directory */
3337 if (!live_in_glue_dir(glue_dir, dev))
3338 return;
3339
3340 mutex_lock(&gdp_mutex);
3341 /**
3342 * There is a race condition between removing glue directory
3343 * and adding a new device under the glue directory.
3344 *
3345 * CPU1: CPU2:
3346 *
3347 * device_add()
3348 * get_device_parent()
3349 * class_dir_create_and_add()
3350 * kobject_add_internal()
3351 * create_dir() // create glue_dir
3352 *
3353 * device_add()
3354 * get_device_parent()
3355 * kobject_get() // get glue_dir
3356 *
3357 * device_del()
3358 * cleanup_glue_dir()
3359 * kobject_del(glue_dir)
3360 *
3361 * kobject_add()
3362 * kobject_add_internal()
3363 * create_dir() // in glue_dir
3364 * sysfs_create_dir_ns()
3365 * kernfs_create_dir_ns(sd)
3366 *
3367 * sysfs_remove_dir() // glue_dir->sd=NULL
3368 * sysfs_put() // free glue_dir->sd
3369 *
3370 * // sd is freed
3371 * kernfs_new_node(sd)
3372 * kernfs_get(glue_dir)
3373 * kernfs_add_one()
3374 * kernfs_put()
3375 *
3376 * Before CPU1 remove last child device under glue dir, if CPU2 add
3377 * a new device under glue dir, the glue_dir kobject reference count
3378 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3379 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3380 * and sysfs_put(). This result in glue_dir->sd is freed.
3381 *
3382 * Then the CPU2 will see a stale "empty" but still potentially used
3383 * glue dir around in kernfs_new_node().
3384 *
3385 * In order to avoid this happening, we also should make sure that
3386 * kernfs_node for glue_dir is released in CPU1 only when refcount
3387 * for glue_dir kobj is 1.
3388 */
3389 ref = kref_read(&glue_dir->kref);
3390 if (!kobject_has_children(glue_dir) && !--ref)
3391 kobject_del(glue_dir);
3392 kobject_put(glue_dir);
3393 mutex_unlock(&gdp_mutex);
3394}
3395
3396static int device_add_class_symlinks(struct device *dev)
3397{
3398 struct device_node *of_node = dev_of_node(dev);
3399 struct subsys_private *sp;
3400 int error;
3401
3402 if (of_node) {
3403 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3404 if (error)
3405 dev_warn(dev, "Error %d creating of_node link\n",error);
3406 /* An error here doesn't warrant bringing down the device */
3407 }
3408
3409 sp = class_to_subsys(dev->class);
3410 if (!sp)
3411 return 0;
3412
3413 error = sysfs_create_link(&dev->kobj, &sp->subsys.kobj, "subsystem");
3414 if (error)
3415 goto out_devnode;
3416
3417 if (dev->parent && device_is_not_partition(dev)) {
3418 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3419 "device");
3420 if (error)
3421 goto out_subsys;
3422 }
3423
3424 /* link in the class directory pointing to the device */
3425 error = sysfs_create_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3426 if (error)
3427 goto out_device;
3428 goto exit;
3429
3430out_device:
3431 sysfs_remove_link(&dev->kobj, "device");
3432out_subsys:
3433 sysfs_remove_link(&dev->kobj, "subsystem");
3434out_devnode:
3435 sysfs_remove_link(&dev->kobj, "of_node");
3436exit:
3437 subsys_put(sp);
3438 return error;
3439}
3440
3441static void device_remove_class_symlinks(struct device *dev)
3442{
3443 struct subsys_private *sp = class_to_subsys(dev->class);
3444
3445 if (dev_of_node(dev))
3446 sysfs_remove_link(&dev->kobj, "of_node");
3447
3448 if (!sp)
3449 return;
3450
3451 if (dev->parent && device_is_not_partition(dev))
3452 sysfs_remove_link(&dev->kobj, "device");
3453 sysfs_remove_link(&dev->kobj, "subsystem");
3454 sysfs_delete_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3455 subsys_put(sp);
3456}
3457
3458/**
3459 * dev_set_name - set a device name
3460 * @dev: device
3461 * @fmt: format string for the device's name
3462 */
3463int dev_set_name(struct device *dev, const char *fmt, ...)
3464{
3465 va_list vargs;
3466 int err;
3467
3468 va_start(vargs, fmt);
3469 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3470 va_end(vargs);
3471 return err;
3472}
3473EXPORT_SYMBOL_GPL(dev_set_name);
3474
3475/* select a /sys/dev/ directory for the device */
3476static struct kobject *device_to_dev_kobj(struct device *dev)
3477{
3478 if (is_blockdev(dev))
3479 return sysfs_dev_block_kobj;
3480 else
3481 return sysfs_dev_char_kobj;
3482}
3483
3484static int device_create_sys_dev_entry(struct device *dev)
3485{
3486 struct kobject *kobj = device_to_dev_kobj(dev);
3487 int error = 0;
3488 char devt_str[15];
3489
3490 if (kobj) {
3491 format_dev_t(devt_str, dev->devt);
3492 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3493 }
3494
3495 return error;
3496}
3497
3498static void device_remove_sys_dev_entry(struct device *dev)
3499{
3500 struct kobject *kobj = device_to_dev_kobj(dev);
3501 char devt_str[15];
3502
3503 if (kobj) {
3504 format_dev_t(devt_str, dev->devt);
3505 sysfs_remove_link(kobj, devt_str);
3506 }
3507}
3508
3509static int device_private_init(struct device *dev)
3510{
3511 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3512 if (!dev->p)
3513 return -ENOMEM;
3514 dev->p->device = dev;
3515 klist_init(&dev->p->klist_children, klist_children_get,
3516 klist_children_put);
3517 INIT_LIST_HEAD(&dev->p->deferred_probe);
3518 return 0;
3519}
3520
3521/**
3522 * device_add - add device to device hierarchy.
3523 * @dev: device.
3524 *
3525 * This is part 2 of device_register(), though may be called
3526 * separately _iff_ device_initialize() has been called separately.
3527 *
3528 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3529 * to the global and sibling lists for the device, then
3530 * adds it to the other relevant subsystems of the driver model.
3531 *
3532 * Do not call this routine or device_register() more than once for
3533 * any device structure. The driver model core is not designed to work
3534 * with devices that get unregistered and then spring back to life.
3535 * (Among other things, it's very hard to guarantee that all references
3536 * to the previous incarnation of @dev have been dropped.) Allocate
3537 * and register a fresh new struct device instead.
3538 *
3539 * NOTE: _Never_ directly free @dev after calling this function, even
3540 * if it returned an error! Always use put_device() to give up your
3541 * reference instead.
3542 *
3543 * Rule of thumb is: if device_add() succeeds, you should call
3544 * device_del() when you want to get rid of it. If device_add() has
3545 * *not* succeeded, use *only* put_device() to drop the reference
3546 * count.
3547 */
3548int device_add(struct device *dev)
3549{
3550 struct subsys_private *sp;
3551 struct device *parent;
3552 struct kobject *kobj;
3553 struct class_interface *class_intf;
3554 int error = -EINVAL;
3555 struct kobject *glue_dir = NULL;
3556
3557 dev = get_device(dev);
3558 if (!dev)
3559 goto done;
3560
3561 if (!dev->p) {
3562 error = device_private_init(dev);
3563 if (error)
3564 goto done;
3565 }
3566
3567 /*
3568 * for statically allocated devices, which should all be converted
3569 * some day, we need to initialize the name. We prevent reading back
3570 * the name, and force the use of dev_name()
3571 */
3572 if (dev->init_name) {
3573 error = dev_set_name(dev, "%s", dev->init_name);
3574 dev->init_name = NULL;
3575 }
3576
3577 if (dev_name(dev))
3578 error = 0;
3579 /* subsystems can specify simple device enumeration */
3580 else if (dev->bus && dev->bus->dev_name)
3581 error = dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3582 else
3583 error = -EINVAL;
3584 if (error)
3585 goto name_error;
3586
3587 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3588
3589 parent = get_device(dev->parent);
3590 kobj = get_device_parent(dev, parent);
3591 if (IS_ERR(kobj)) {
3592 error = PTR_ERR(kobj);
3593 goto parent_error;
3594 }
3595 if (kobj)
3596 dev->kobj.parent = kobj;
3597
3598 /* use parent numa_node */
3599 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3600 set_dev_node(dev, dev_to_node(parent));
3601
3602 /* first, register with generic layer. */
3603 /* we require the name to be set before, and pass NULL */
3604 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3605 if (error) {
3606 glue_dir = kobj;
3607 goto Error;
3608 }
3609
3610 /* notify platform of device entry */
3611 device_platform_notify(dev);
3612
3613 error = device_create_file(dev, &dev_attr_uevent);
3614 if (error)
3615 goto attrError;
3616
3617 error = device_add_class_symlinks(dev);
3618 if (error)
3619 goto SymlinkError;
3620 error = device_add_attrs(dev);
3621 if (error)
3622 goto AttrsError;
3623 error = bus_add_device(dev);
3624 if (error)
3625 goto BusError;
3626 error = dpm_sysfs_add(dev);
3627 if (error)
3628 goto DPMError;
3629 device_pm_add(dev);
3630
3631 if (MAJOR(dev->devt)) {
3632 error = device_create_file(dev, &dev_attr_dev);
3633 if (error)
3634 goto DevAttrError;
3635
3636 error = device_create_sys_dev_entry(dev);
3637 if (error)
3638 goto SysEntryError;
3639
3640 devtmpfs_create_node(dev);
3641 }
3642
3643 /* Notify clients of device addition. This call must come
3644 * after dpm_sysfs_add() and before kobject_uevent().
3645 */
3646 bus_notify(dev, BUS_NOTIFY_ADD_DEVICE);
3647 kobject_uevent(&dev->kobj, KOBJ_ADD);
3648
3649 /*
3650 * Check if any of the other devices (consumers) have been waiting for
3651 * this device (supplier) to be added so that they can create a device
3652 * link to it.
3653 *
3654 * This needs to happen after device_pm_add() because device_link_add()
3655 * requires the supplier be registered before it's called.
3656 *
3657 * But this also needs to happen before bus_probe_device() to make sure
3658 * waiting consumers can link to it before the driver is bound to the
3659 * device and the driver sync_state callback is called for this device.
3660 */
3661 if (dev->fwnode && !dev->fwnode->dev) {
3662 dev->fwnode->dev = dev;
3663 fw_devlink_link_device(dev);
3664 }
3665
3666 bus_probe_device(dev);
3667
3668 /*
3669 * If all driver registration is done and a newly added device doesn't
3670 * match with any driver, don't block its consumers from probing in
3671 * case the consumer device is able to operate without this supplier.
3672 */
3673 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3674 fw_devlink_unblock_consumers(dev);
3675
3676 if (parent)
3677 klist_add_tail(&dev->p->knode_parent,
3678 &parent->p->klist_children);
3679
3680 sp = class_to_subsys(dev->class);
3681 if (sp) {
3682 mutex_lock(&sp->mutex);
3683 /* tie the class to the device */
3684 klist_add_tail(&dev->p->knode_class, &sp->klist_devices);
3685
3686 /* notify any interfaces that the device is here */
3687 list_for_each_entry(class_intf, &sp->interfaces, node)
3688 if (class_intf->add_dev)
3689 class_intf->add_dev(dev);
3690 mutex_unlock(&sp->mutex);
3691 subsys_put(sp);
3692 }
3693done:
3694 put_device(dev);
3695 return error;
3696 SysEntryError:
3697 if (MAJOR(dev->devt))
3698 device_remove_file(dev, &dev_attr_dev);
3699 DevAttrError:
3700 device_pm_remove(dev);
3701 dpm_sysfs_remove(dev);
3702 DPMError:
3703 dev->driver = NULL;
3704 bus_remove_device(dev);
3705 BusError:
3706 device_remove_attrs(dev);
3707 AttrsError:
3708 device_remove_class_symlinks(dev);
3709 SymlinkError:
3710 device_remove_file(dev, &dev_attr_uevent);
3711 attrError:
3712 device_platform_notify_remove(dev);
3713 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3714 glue_dir = get_glue_dir(dev);
3715 kobject_del(&dev->kobj);
3716 Error:
3717 cleanup_glue_dir(dev, glue_dir);
3718parent_error:
3719 put_device(parent);
3720name_error:
3721 kfree(dev->p);
3722 dev->p = NULL;
3723 goto done;
3724}
3725EXPORT_SYMBOL_GPL(device_add);
3726
3727/**
3728 * device_register - register a device with the system.
3729 * @dev: pointer to the device structure
3730 *
3731 * This happens in two clean steps - initialize the device
3732 * and add it to the system. The two steps can be called
3733 * separately, but this is the easiest and most common.
3734 * I.e. you should only call the two helpers separately if
3735 * have a clearly defined need to use and refcount the device
3736 * before it is added to the hierarchy.
3737 *
3738 * For more information, see the kerneldoc for device_initialize()
3739 * and device_add().
3740 *
3741 * NOTE: _Never_ directly free @dev after calling this function, even
3742 * if it returned an error! Always use put_device() to give up the
3743 * reference initialized in this function instead.
3744 */
3745int device_register(struct device *dev)
3746{
3747 device_initialize(dev);
3748 return device_add(dev);
3749}
3750EXPORT_SYMBOL_GPL(device_register);
3751
3752/**
3753 * get_device - increment reference count for device.
3754 * @dev: device.
3755 *
3756 * This simply forwards the call to kobject_get(), though
3757 * we do take care to provide for the case that we get a NULL
3758 * pointer passed in.
3759 */
3760struct device *get_device(struct device *dev)
3761{
3762 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3763}
3764EXPORT_SYMBOL_GPL(get_device);
3765
3766/**
3767 * put_device - decrement reference count.
3768 * @dev: device in question.
3769 */
3770void put_device(struct device *dev)
3771{
3772 /* might_sleep(); */
3773 if (dev)
3774 kobject_put(&dev->kobj);
3775}
3776EXPORT_SYMBOL_GPL(put_device);
3777
3778bool kill_device(struct device *dev)
3779{
3780 /*
3781 * Require the device lock and set the "dead" flag to guarantee that
3782 * the update behavior is consistent with the other bitfields near
3783 * it and that we cannot have an asynchronous probe routine trying
3784 * to run while we are tearing out the bus/class/sysfs from
3785 * underneath the device.
3786 */
3787 device_lock_assert(dev);
3788
3789 if (dev->p->dead)
3790 return false;
3791 dev->p->dead = true;
3792 return true;
3793}
3794EXPORT_SYMBOL_GPL(kill_device);
3795
3796/**
3797 * device_del - delete device from system.
3798 * @dev: device.
3799 *
3800 * This is the first part of the device unregistration
3801 * sequence. This removes the device from the lists we control
3802 * from here, has it removed from the other driver model
3803 * subsystems it was added to in device_add(), and removes it
3804 * from the kobject hierarchy.
3805 *
3806 * NOTE: this should be called manually _iff_ device_add() was
3807 * also called manually.
3808 */
3809void device_del(struct device *dev)
3810{
3811 struct subsys_private *sp;
3812 struct device *parent = dev->parent;
3813 struct kobject *glue_dir = NULL;
3814 struct class_interface *class_intf;
3815 unsigned int noio_flag;
3816
3817 device_lock(dev);
3818 kill_device(dev);
3819 device_unlock(dev);
3820
3821 if (dev->fwnode && dev->fwnode->dev == dev)
3822 dev->fwnode->dev = NULL;
3823
3824 /* Notify clients of device removal. This call must come
3825 * before dpm_sysfs_remove().
3826 */
3827 noio_flag = memalloc_noio_save();
3828 bus_notify(dev, BUS_NOTIFY_DEL_DEVICE);
3829
3830 dpm_sysfs_remove(dev);
3831 if (parent)
3832 klist_del(&dev->p->knode_parent);
3833 if (MAJOR(dev->devt)) {
3834 devtmpfs_delete_node(dev);
3835 device_remove_sys_dev_entry(dev);
3836 device_remove_file(dev, &dev_attr_dev);
3837 }
3838
3839 sp = class_to_subsys(dev->class);
3840 if (sp) {
3841 device_remove_class_symlinks(dev);
3842
3843 mutex_lock(&sp->mutex);
3844 /* notify any interfaces that the device is now gone */
3845 list_for_each_entry(class_intf, &sp->interfaces, node)
3846 if (class_intf->remove_dev)
3847 class_intf->remove_dev(dev);
3848 /* remove the device from the class list */
3849 klist_del(&dev->p->knode_class);
3850 mutex_unlock(&sp->mutex);
3851 subsys_put(sp);
3852 }
3853 device_remove_file(dev, &dev_attr_uevent);
3854 device_remove_attrs(dev);
3855 bus_remove_device(dev);
3856 device_pm_remove(dev);
3857 driver_deferred_probe_del(dev);
3858 device_platform_notify_remove(dev);
3859 device_links_purge(dev);
3860
3861 /*
3862 * If a device does not have a driver attached, we need to clean
3863 * up any managed resources. We do this in device_release(), but
3864 * it's never called (and we leak the device) if a managed
3865 * resource holds a reference to the device. So release all
3866 * managed resources here, like we do in driver_detach(). We
3867 * still need to do so again in device_release() in case someone
3868 * adds a new resource after this point, though.
3869 */
3870 devres_release_all(dev);
3871
3872 bus_notify(dev, BUS_NOTIFY_REMOVED_DEVICE);
3873 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3874 glue_dir = get_glue_dir(dev);
3875 kobject_del(&dev->kobj);
3876 cleanup_glue_dir(dev, glue_dir);
3877 memalloc_noio_restore(noio_flag);
3878 put_device(parent);
3879}
3880EXPORT_SYMBOL_GPL(device_del);
3881
3882/**
3883 * device_unregister - unregister device from system.
3884 * @dev: device going away.
3885 *
3886 * We do this in two parts, like we do device_register(). First,
3887 * we remove it from all the subsystems with device_del(), then
3888 * we decrement the reference count via put_device(). If that
3889 * is the final reference count, the device will be cleaned up
3890 * via device_release() above. Otherwise, the structure will
3891 * stick around until the final reference to the device is dropped.
3892 */
3893void device_unregister(struct device *dev)
3894{
3895 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3896 device_del(dev);
3897 put_device(dev);
3898}
3899EXPORT_SYMBOL_GPL(device_unregister);
3900
3901static struct device *prev_device(struct klist_iter *i)
3902{
3903 struct klist_node *n = klist_prev(i);
3904 struct device *dev = NULL;
3905 struct device_private *p;
3906
3907 if (n) {
3908 p = to_device_private_parent(n);
3909 dev = p->device;
3910 }
3911 return dev;
3912}
3913
3914static struct device *next_device(struct klist_iter *i)
3915{
3916 struct klist_node *n = klist_next(i);
3917 struct device *dev = NULL;
3918 struct device_private *p;
3919
3920 if (n) {
3921 p = to_device_private_parent(n);
3922 dev = p->device;
3923 }
3924 return dev;
3925}
3926
3927/**
3928 * device_get_devnode - path of device node file
3929 * @dev: device
3930 * @mode: returned file access mode
3931 * @uid: returned file owner
3932 * @gid: returned file group
3933 * @tmp: possibly allocated string
3934 *
3935 * Return the relative path of a possible device node.
3936 * Non-default names may need to allocate a memory to compose
3937 * a name. This memory is returned in tmp and needs to be
3938 * freed by the caller.
3939 */
3940const char *device_get_devnode(const struct device *dev,
3941 umode_t *mode, kuid_t *uid, kgid_t *gid,
3942 const char **tmp)
3943{
3944 char *s;
3945
3946 *tmp = NULL;
3947
3948 /* the device type may provide a specific name */
3949 if (dev->type && dev->type->devnode)
3950 *tmp = dev->type->devnode(dev, mode, uid, gid);
3951 if (*tmp)
3952 return *tmp;
3953
3954 /* the class may provide a specific name */
3955 if (dev->class && dev->class->devnode)
3956 *tmp = dev->class->devnode(dev, mode);
3957 if (*tmp)
3958 return *tmp;
3959
3960 /* return name without allocation, tmp == NULL */
3961 if (strchr(dev_name(dev), '!') == NULL)
3962 return dev_name(dev);
3963
3964 /* replace '!' in the name with '/' */
3965 s = kstrdup_and_replace(dev_name(dev), '!', '/', GFP_KERNEL);
3966 if (!s)
3967 return NULL;
3968 return *tmp = s;
3969}
3970
3971/**
3972 * device_for_each_child - device child iterator.
3973 * @parent: parent struct device.
3974 * @fn: function to be called for each device.
3975 * @data: data for the callback.
3976 *
3977 * Iterate over @parent's child devices, and call @fn for each,
3978 * passing it @data.
3979 *
3980 * We check the return of @fn each time. If it returns anything
3981 * other than 0, we break out and return that value.
3982 */
3983int device_for_each_child(struct device *parent, void *data,
3984 int (*fn)(struct device *dev, void *data))
3985{
3986 struct klist_iter i;
3987 struct device *child;
3988 int error = 0;
3989
3990 if (!parent || !parent->p)
3991 return 0;
3992
3993 klist_iter_init(&parent->p->klist_children, &i);
3994 while (!error && (child = next_device(&i)))
3995 error = fn(child, data);
3996 klist_iter_exit(&i);
3997 return error;
3998}
3999EXPORT_SYMBOL_GPL(device_for_each_child);
4000
4001/**
4002 * device_for_each_child_reverse - device child iterator in reversed order.
4003 * @parent: parent struct device.
4004 * @fn: function to be called for each device.
4005 * @data: data for the callback.
4006 *
4007 * Iterate over @parent's child devices, and call @fn for each,
4008 * passing it @data.
4009 *
4010 * We check the return of @fn each time. If it returns anything
4011 * other than 0, we break out and return that value.
4012 */
4013int device_for_each_child_reverse(struct device *parent, void *data,
4014 int (*fn)(struct device *dev, void *data))
4015{
4016 struct klist_iter i;
4017 struct device *child;
4018 int error = 0;
4019
4020 if (!parent || !parent->p)
4021 return 0;
4022
4023 klist_iter_init(&parent->p->klist_children, &i);
4024 while ((child = prev_device(&i)) && !error)
4025 error = fn(child, data);
4026 klist_iter_exit(&i);
4027 return error;
4028}
4029EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
4030
4031/**
4032 * device_for_each_child_reverse_from - device child iterator in reversed order.
4033 * @parent: parent struct device.
4034 * @from: optional starting point in child list
4035 * @fn: function to be called for each device.
4036 * @data: data for the callback.
4037 *
4038 * Iterate over @parent's child devices, starting at @from, and call @fn
4039 * for each, passing it @data. This helper is identical to
4040 * device_for_each_child_reverse() when @from is NULL.
4041 *
4042 * @fn is checked each iteration. If it returns anything other than 0,
4043 * iteration stop and that value is returned to the caller of
4044 * device_for_each_child_reverse_from();
4045 */
4046int device_for_each_child_reverse_from(struct device *parent,
4047 struct device *from, const void *data,
4048 int (*fn)(struct device *, const void *))
4049{
4050 struct klist_iter i;
4051 struct device *child;
4052 int error = 0;
4053
4054 if (!parent->p)
4055 return 0;
4056
4057 klist_iter_init_node(&parent->p->klist_children, &i,
4058 (from ? &from->p->knode_parent : NULL));
4059 while ((child = prev_device(&i)) && !error)
4060 error = fn(child, data);
4061 klist_iter_exit(&i);
4062 return error;
4063}
4064EXPORT_SYMBOL_GPL(device_for_each_child_reverse_from);
4065
4066/**
4067 * device_find_child - device iterator for locating a particular device.
4068 * @parent: parent struct device
4069 * @match: Callback function to check device
4070 * @data: Data to pass to match function
4071 *
4072 * This is similar to the device_for_each_child() function above, but it
4073 * returns a reference to a device that is 'found' for later use, as
4074 * determined by the @match callback.
4075 *
4076 * The callback should return 0 if the device doesn't match and non-zero
4077 * if it does. If the callback returns non-zero and a reference to the
4078 * current device can be obtained, this function will return to the caller
4079 * and not iterate over any more devices.
4080 *
4081 * NOTE: you will need to drop the reference with put_device() after use.
4082 */
4083struct device *device_find_child(struct device *parent, void *data,
4084 int (*match)(struct device *dev, void *data))
4085{
4086 struct klist_iter i;
4087 struct device *child;
4088
4089 if (!parent || !parent->p)
4090 return NULL;
4091
4092 klist_iter_init(&parent->p->klist_children, &i);
4093 while ((child = next_device(&i)))
4094 if (match(child, data) && get_device(child))
4095 break;
4096 klist_iter_exit(&i);
4097 return child;
4098}
4099EXPORT_SYMBOL_GPL(device_find_child);
4100
4101/**
4102 * device_find_child_by_name - device iterator for locating a child device.
4103 * @parent: parent struct device
4104 * @name: name of the child device
4105 *
4106 * This is similar to the device_find_child() function above, but it
4107 * returns a reference to a device that has the name @name.
4108 *
4109 * NOTE: you will need to drop the reference with put_device() after use.
4110 */
4111struct device *device_find_child_by_name(struct device *parent,
4112 const char *name)
4113{
4114 struct klist_iter i;
4115 struct device *child;
4116
4117 if (!parent)
4118 return NULL;
4119
4120 klist_iter_init(&parent->p->klist_children, &i);
4121 while ((child = next_device(&i)))
4122 if (sysfs_streq(dev_name(child), name) && get_device(child))
4123 break;
4124 klist_iter_exit(&i);
4125 return child;
4126}
4127EXPORT_SYMBOL_GPL(device_find_child_by_name);
4128
4129static int match_any(struct device *dev, void *unused)
4130{
4131 return 1;
4132}
4133
4134/**
4135 * device_find_any_child - device iterator for locating a child device, if any.
4136 * @parent: parent struct device
4137 *
4138 * This is similar to the device_find_child() function above, but it
4139 * returns a reference to a child device, if any.
4140 *
4141 * NOTE: you will need to drop the reference with put_device() after use.
4142 */
4143struct device *device_find_any_child(struct device *parent)
4144{
4145 return device_find_child(parent, NULL, match_any);
4146}
4147EXPORT_SYMBOL_GPL(device_find_any_child);
4148
4149int __init devices_init(void)
4150{
4151 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
4152 if (!devices_kset)
4153 return -ENOMEM;
4154 dev_kobj = kobject_create_and_add("dev", NULL);
4155 if (!dev_kobj)
4156 goto dev_kobj_err;
4157 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
4158 if (!sysfs_dev_block_kobj)
4159 goto block_kobj_err;
4160 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
4161 if (!sysfs_dev_char_kobj)
4162 goto char_kobj_err;
4163 device_link_wq = alloc_workqueue("device_link_wq", 0, 0);
4164 if (!device_link_wq)
4165 goto wq_err;
4166
4167 return 0;
4168
4169 wq_err:
4170 kobject_put(sysfs_dev_char_kobj);
4171 char_kobj_err:
4172 kobject_put(sysfs_dev_block_kobj);
4173 block_kobj_err:
4174 kobject_put(dev_kobj);
4175 dev_kobj_err:
4176 kset_unregister(devices_kset);
4177 return -ENOMEM;
4178}
4179
4180static int device_check_offline(struct device *dev, void *not_used)
4181{
4182 int ret;
4183
4184 ret = device_for_each_child(dev, NULL, device_check_offline);
4185 if (ret)
4186 return ret;
4187
4188 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
4189}
4190
4191/**
4192 * device_offline - Prepare the device for hot-removal.
4193 * @dev: Device to be put offline.
4194 *
4195 * Execute the device bus type's .offline() callback, if present, to prepare
4196 * the device for a subsequent hot-removal. If that succeeds, the device must
4197 * not be used until either it is removed or its bus type's .online() callback
4198 * is executed.
4199 *
4200 * Call under device_hotplug_lock.
4201 */
4202int device_offline(struct device *dev)
4203{
4204 int ret;
4205
4206 if (dev->offline_disabled)
4207 return -EPERM;
4208
4209 ret = device_for_each_child(dev, NULL, device_check_offline);
4210 if (ret)
4211 return ret;
4212
4213 device_lock(dev);
4214 if (device_supports_offline(dev)) {
4215 if (dev->offline) {
4216 ret = 1;
4217 } else {
4218 ret = dev->bus->offline(dev);
4219 if (!ret) {
4220 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
4221 dev->offline = true;
4222 }
4223 }
4224 }
4225 device_unlock(dev);
4226
4227 return ret;
4228}
4229
4230/**
4231 * device_online - Put the device back online after successful device_offline().
4232 * @dev: Device to be put back online.
4233 *
4234 * If device_offline() has been successfully executed for @dev, but the device
4235 * has not been removed subsequently, execute its bus type's .online() callback
4236 * to indicate that the device can be used again.
4237 *
4238 * Call under device_hotplug_lock.
4239 */
4240int device_online(struct device *dev)
4241{
4242 int ret = 0;
4243
4244 device_lock(dev);
4245 if (device_supports_offline(dev)) {
4246 if (dev->offline) {
4247 ret = dev->bus->online(dev);
4248 if (!ret) {
4249 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
4250 dev->offline = false;
4251 }
4252 } else {
4253 ret = 1;
4254 }
4255 }
4256 device_unlock(dev);
4257
4258 return ret;
4259}
4260
4261struct root_device {
4262 struct device dev;
4263 struct module *owner;
4264};
4265
4266static inline struct root_device *to_root_device(struct device *d)
4267{
4268 return container_of(d, struct root_device, dev);
4269}
4270
4271static void root_device_release(struct device *dev)
4272{
4273 kfree(to_root_device(dev));
4274}
4275
4276/**
4277 * __root_device_register - allocate and register a root device
4278 * @name: root device name
4279 * @owner: owner module of the root device, usually THIS_MODULE
4280 *
4281 * This function allocates a root device and registers it
4282 * using device_register(). In order to free the returned
4283 * device, use root_device_unregister().
4284 *
4285 * Root devices are dummy devices which allow other devices
4286 * to be grouped under /sys/devices. Use this function to
4287 * allocate a root device and then use it as the parent of
4288 * any device which should appear under /sys/devices/{name}
4289 *
4290 * The /sys/devices/{name} directory will also contain a
4291 * 'module' symlink which points to the @owner directory
4292 * in sysfs.
4293 *
4294 * Returns &struct device pointer on success, or ERR_PTR() on error.
4295 *
4296 * Note: You probably want to use root_device_register().
4297 */
4298struct device *__root_device_register(const char *name, struct module *owner)
4299{
4300 struct root_device *root;
4301 int err = -ENOMEM;
4302
4303 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
4304 if (!root)
4305 return ERR_PTR(err);
4306
4307 err = dev_set_name(&root->dev, "%s", name);
4308 if (err) {
4309 kfree(root);
4310 return ERR_PTR(err);
4311 }
4312
4313 root->dev.release = root_device_release;
4314
4315 err = device_register(&root->dev);
4316 if (err) {
4317 put_device(&root->dev);
4318 return ERR_PTR(err);
4319 }
4320
4321#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
4322 if (owner) {
4323 struct module_kobject *mk = &owner->mkobj;
4324
4325 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
4326 if (err) {
4327 device_unregister(&root->dev);
4328 return ERR_PTR(err);
4329 }
4330 root->owner = owner;
4331 }
4332#endif
4333
4334 return &root->dev;
4335}
4336EXPORT_SYMBOL_GPL(__root_device_register);
4337
4338/**
4339 * root_device_unregister - unregister and free a root device
4340 * @dev: device going away
4341 *
4342 * This function unregisters and cleans up a device that was created by
4343 * root_device_register().
4344 */
4345void root_device_unregister(struct device *dev)
4346{
4347 struct root_device *root = to_root_device(dev);
4348
4349 if (root->owner)
4350 sysfs_remove_link(&root->dev.kobj, "module");
4351
4352 device_unregister(dev);
4353}
4354EXPORT_SYMBOL_GPL(root_device_unregister);
4355
4356
4357static void device_create_release(struct device *dev)
4358{
4359 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4360 kfree(dev);
4361}
4362
4363static __printf(6, 0) struct device *
4364device_create_groups_vargs(const struct class *class, struct device *parent,
4365 dev_t devt, void *drvdata,
4366 const struct attribute_group **groups,
4367 const char *fmt, va_list args)
4368{
4369 struct device *dev = NULL;
4370 int retval = -ENODEV;
4371
4372 if (IS_ERR_OR_NULL(class))
4373 goto error;
4374
4375 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4376 if (!dev) {
4377 retval = -ENOMEM;
4378 goto error;
4379 }
4380
4381 device_initialize(dev);
4382 dev->devt = devt;
4383 dev->class = class;
4384 dev->parent = parent;
4385 dev->groups = groups;
4386 dev->release = device_create_release;
4387 dev_set_drvdata(dev, drvdata);
4388
4389 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4390 if (retval)
4391 goto error;
4392
4393 retval = device_add(dev);
4394 if (retval)
4395 goto error;
4396
4397 return dev;
4398
4399error:
4400 put_device(dev);
4401 return ERR_PTR(retval);
4402}
4403
4404/**
4405 * device_create - creates a device and registers it with sysfs
4406 * @class: pointer to the struct class that this device should be registered to
4407 * @parent: pointer to the parent struct device of this new device, if any
4408 * @devt: the dev_t for the char device to be added
4409 * @drvdata: the data to be added to the device for callbacks
4410 * @fmt: string for the device's name
4411 *
4412 * This function can be used by char device classes. A struct device
4413 * will be created in sysfs, registered to the specified class.
4414 *
4415 * A "dev" file will be created, showing the dev_t for the device, if
4416 * the dev_t is not 0,0.
4417 * If a pointer to a parent struct device is passed in, the newly created
4418 * struct device will be a child of that device in sysfs.
4419 * The pointer to the struct device will be returned from the call.
4420 * Any further sysfs files that might be required can be created using this
4421 * pointer.
4422 *
4423 * Returns &struct device pointer on success, or ERR_PTR() on error.
4424 */
4425struct device *device_create(const struct class *class, struct device *parent,
4426 dev_t devt, void *drvdata, const char *fmt, ...)
4427{
4428 va_list vargs;
4429 struct device *dev;
4430
4431 va_start(vargs, fmt);
4432 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4433 fmt, vargs);
4434 va_end(vargs);
4435 return dev;
4436}
4437EXPORT_SYMBOL_GPL(device_create);
4438
4439/**
4440 * device_create_with_groups - creates a device and registers it with sysfs
4441 * @class: pointer to the struct class that this device should be registered to
4442 * @parent: pointer to the parent struct device of this new device, if any
4443 * @devt: the dev_t for the char device to be added
4444 * @drvdata: the data to be added to the device for callbacks
4445 * @groups: NULL-terminated list of attribute groups to be created
4446 * @fmt: string for the device's name
4447 *
4448 * This function can be used by char device classes. A struct device
4449 * will be created in sysfs, registered to the specified class.
4450 * Additional attributes specified in the groups parameter will also
4451 * be created automatically.
4452 *
4453 * A "dev" file will be created, showing the dev_t for the device, if
4454 * the dev_t is not 0,0.
4455 * If a pointer to a parent struct device is passed in, the newly created
4456 * struct device will be a child of that device in sysfs.
4457 * The pointer to the struct device will be returned from the call.
4458 * Any further sysfs files that might be required can be created using this
4459 * pointer.
4460 *
4461 * Returns &struct device pointer on success, or ERR_PTR() on error.
4462 */
4463struct device *device_create_with_groups(const struct class *class,
4464 struct device *parent, dev_t devt,
4465 void *drvdata,
4466 const struct attribute_group **groups,
4467 const char *fmt, ...)
4468{
4469 va_list vargs;
4470 struct device *dev;
4471
4472 va_start(vargs, fmt);
4473 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4474 fmt, vargs);
4475 va_end(vargs);
4476 return dev;
4477}
4478EXPORT_SYMBOL_GPL(device_create_with_groups);
4479
4480/**
4481 * device_destroy - removes a device that was created with device_create()
4482 * @class: pointer to the struct class that this device was registered with
4483 * @devt: the dev_t of the device that was previously registered
4484 *
4485 * This call unregisters and cleans up a device that was created with a
4486 * call to device_create().
4487 */
4488void device_destroy(const struct class *class, dev_t devt)
4489{
4490 struct device *dev;
4491
4492 dev = class_find_device_by_devt(class, devt);
4493 if (dev) {
4494 put_device(dev);
4495 device_unregister(dev);
4496 }
4497}
4498EXPORT_SYMBOL_GPL(device_destroy);
4499
4500/**
4501 * device_rename - renames a device
4502 * @dev: the pointer to the struct device to be renamed
4503 * @new_name: the new name of the device
4504 *
4505 * It is the responsibility of the caller to provide mutual
4506 * exclusion between two different calls of device_rename
4507 * on the same device to ensure that new_name is valid and
4508 * won't conflict with other devices.
4509 *
4510 * Note: given that some subsystems (networking and infiniband) use this
4511 * function, with no immediate plans for this to change, we cannot assume or
4512 * require that this function not be called at all.
4513 *
4514 * However, if you're writing new code, do not call this function. The following
4515 * text from Kay Sievers offers some insight:
4516 *
4517 * Renaming devices is racy at many levels, symlinks and other stuff are not
4518 * replaced atomically, and you get a "move" uevent, but it's not easy to
4519 * connect the event to the old and new device. Device nodes are not renamed at
4520 * all, there isn't even support for that in the kernel now.
4521 *
4522 * In the meantime, during renaming, your target name might be taken by another
4523 * driver, creating conflicts. Or the old name is taken directly after you
4524 * renamed it -- then you get events for the same DEVPATH, before you even see
4525 * the "move" event. It's just a mess, and nothing new should ever rely on
4526 * kernel device renaming. Besides that, it's not even implemented now for
4527 * other things than (driver-core wise very simple) network devices.
4528 *
4529 * Make up a "real" name in the driver before you register anything, or add
4530 * some other attributes for userspace to find the device, or use udev to add
4531 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4532 * don't even want to get into that and try to implement the missing pieces in
4533 * the core. We really have other pieces to fix in the driver core mess. :)
4534 */
4535int device_rename(struct device *dev, const char *new_name)
4536{
4537 struct subsys_private *sp = NULL;
4538 struct kobject *kobj = &dev->kobj;
4539 char *old_device_name = NULL;
4540 int error;
4541 bool is_link_renamed = false;
4542
4543 dev = get_device(dev);
4544 if (!dev)
4545 return -EINVAL;
4546
4547 dev_dbg(dev, "renaming to %s\n", new_name);
4548
4549 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4550 if (!old_device_name) {
4551 error = -ENOMEM;
4552 goto out;
4553 }
4554
4555 if (dev->class) {
4556 sp = class_to_subsys(dev->class);
4557
4558 if (!sp) {
4559 error = -EINVAL;
4560 goto out;
4561 }
4562
4563 error = sysfs_rename_link_ns(&sp->subsys.kobj, kobj, old_device_name,
4564 new_name, kobject_namespace(kobj));
4565 if (error)
4566 goto out;
4567
4568 is_link_renamed = true;
4569 }
4570
4571 error = kobject_rename(kobj, new_name);
4572out:
4573 if (error && is_link_renamed)
4574 sysfs_rename_link_ns(&sp->subsys.kobj, kobj, new_name,
4575 old_device_name, kobject_namespace(kobj));
4576 subsys_put(sp);
4577
4578 put_device(dev);
4579
4580 kfree(old_device_name);
4581
4582 return error;
4583}
4584EXPORT_SYMBOL_GPL(device_rename);
4585
4586static int device_move_class_links(struct device *dev,
4587 struct device *old_parent,
4588 struct device *new_parent)
4589{
4590 int error = 0;
4591
4592 if (old_parent)
4593 sysfs_remove_link(&dev->kobj, "device");
4594 if (new_parent)
4595 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4596 "device");
4597 return error;
4598}
4599
4600/**
4601 * device_move - moves a device to a new parent
4602 * @dev: the pointer to the struct device to be moved
4603 * @new_parent: the new parent of the device (can be NULL)
4604 * @dpm_order: how to reorder the dpm_list
4605 */
4606int device_move(struct device *dev, struct device *new_parent,
4607 enum dpm_order dpm_order)
4608{
4609 int error;
4610 struct device *old_parent;
4611 struct kobject *new_parent_kobj;
4612
4613 dev = get_device(dev);
4614 if (!dev)
4615 return -EINVAL;
4616
4617 device_pm_lock();
4618 new_parent = get_device(new_parent);
4619 new_parent_kobj = get_device_parent(dev, new_parent);
4620 if (IS_ERR(new_parent_kobj)) {
4621 error = PTR_ERR(new_parent_kobj);
4622 put_device(new_parent);
4623 goto out;
4624 }
4625
4626 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4627 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4628 error = kobject_move(&dev->kobj, new_parent_kobj);
4629 if (error) {
4630 cleanup_glue_dir(dev, new_parent_kobj);
4631 put_device(new_parent);
4632 goto out;
4633 }
4634 old_parent = dev->parent;
4635 dev->parent = new_parent;
4636 if (old_parent)
4637 klist_remove(&dev->p->knode_parent);
4638 if (new_parent) {
4639 klist_add_tail(&dev->p->knode_parent,
4640 &new_parent->p->klist_children);
4641 set_dev_node(dev, dev_to_node(new_parent));
4642 }
4643
4644 if (dev->class) {
4645 error = device_move_class_links(dev, old_parent, new_parent);
4646 if (error) {
4647 /* We ignore errors on cleanup since we're hosed anyway... */
4648 device_move_class_links(dev, new_parent, old_parent);
4649 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4650 if (new_parent)
4651 klist_remove(&dev->p->knode_parent);
4652 dev->parent = old_parent;
4653 if (old_parent) {
4654 klist_add_tail(&dev->p->knode_parent,
4655 &old_parent->p->klist_children);
4656 set_dev_node(dev, dev_to_node(old_parent));
4657 }
4658 }
4659 cleanup_glue_dir(dev, new_parent_kobj);
4660 put_device(new_parent);
4661 goto out;
4662 }
4663 }
4664 switch (dpm_order) {
4665 case DPM_ORDER_NONE:
4666 break;
4667 case DPM_ORDER_DEV_AFTER_PARENT:
4668 device_pm_move_after(dev, new_parent);
4669 devices_kset_move_after(dev, new_parent);
4670 break;
4671 case DPM_ORDER_PARENT_BEFORE_DEV:
4672 device_pm_move_before(new_parent, dev);
4673 devices_kset_move_before(new_parent, dev);
4674 break;
4675 case DPM_ORDER_DEV_LAST:
4676 device_pm_move_last(dev);
4677 devices_kset_move_last(dev);
4678 break;
4679 }
4680
4681 put_device(old_parent);
4682out:
4683 device_pm_unlock();
4684 put_device(dev);
4685 return error;
4686}
4687EXPORT_SYMBOL_GPL(device_move);
4688
4689static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4690 kgid_t kgid)
4691{
4692 struct kobject *kobj = &dev->kobj;
4693 const struct class *class = dev->class;
4694 const struct device_type *type = dev->type;
4695 int error;
4696
4697 if (class) {
4698 /*
4699 * Change the device groups of the device class for @dev to
4700 * @kuid/@kgid.
4701 */
4702 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4703 kgid);
4704 if (error)
4705 return error;
4706 }
4707
4708 if (type) {
4709 /*
4710 * Change the device groups of the device type for @dev to
4711 * @kuid/@kgid.
4712 */
4713 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4714 kgid);
4715 if (error)
4716 return error;
4717 }
4718
4719 /* Change the device groups of @dev to @kuid/@kgid. */
4720 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4721 if (error)
4722 return error;
4723
4724 if (device_supports_offline(dev) && !dev->offline_disabled) {
4725 /* Change online device attributes of @dev to @kuid/@kgid. */
4726 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4727 kuid, kgid);
4728 if (error)
4729 return error;
4730 }
4731
4732 return 0;
4733}
4734
4735/**
4736 * device_change_owner - change the owner of an existing device.
4737 * @dev: device.
4738 * @kuid: new owner's kuid
4739 * @kgid: new owner's kgid
4740 *
4741 * This changes the owner of @dev and its corresponding sysfs entries to
4742 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4743 * core.
4744 *
4745 * Returns 0 on success or error code on failure.
4746 */
4747int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4748{
4749 int error;
4750 struct kobject *kobj = &dev->kobj;
4751 struct subsys_private *sp;
4752
4753 dev = get_device(dev);
4754 if (!dev)
4755 return -EINVAL;
4756
4757 /*
4758 * Change the kobject and the default attributes and groups of the
4759 * ktype associated with it to @kuid/@kgid.
4760 */
4761 error = sysfs_change_owner(kobj, kuid, kgid);
4762 if (error)
4763 goto out;
4764
4765 /*
4766 * Change the uevent file for @dev to the new owner. The uevent file
4767 * was created in a separate step when @dev got added and we mirror
4768 * that step here.
4769 */
4770 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4771 kgid);
4772 if (error)
4773 goto out;
4774
4775 /*
4776 * Change the device groups, the device groups associated with the
4777 * device class, and the groups associated with the device type of @dev
4778 * to @kuid/@kgid.
4779 */
4780 error = device_attrs_change_owner(dev, kuid, kgid);
4781 if (error)
4782 goto out;
4783
4784 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4785 if (error)
4786 goto out;
4787
4788 /*
4789 * Change the owner of the symlink located in the class directory of
4790 * the device class associated with @dev which points to the actual
4791 * directory entry for @dev to @kuid/@kgid. This ensures that the
4792 * symlink shows the same permissions as its target.
4793 */
4794 sp = class_to_subsys(dev->class);
4795 if (!sp) {
4796 error = -EINVAL;
4797 goto out;
4798 }
4799 error = sysfs_link_change_owner(&sp->subsys.kobj, &dev->kobj, dev_name(dev), kuid, kgid);
4800 subsys_put(sp);
4801
4802out:
4803 put_device(dev);
4804 return error;
4805}
4806EXPORT_SYMBOL_GPL(device_change_owner);
4807
4808/**
4809 * device_shutdown - call ->shutdown() on each device to shutdown.
4810 */
4811void device_shutdown(void)
4812{
4813 struct device *dev, *parent;
4814
4815 wait_for_device_probe();
4816 device_block_probing();
4817
4818 cpufreq_suspend();
4819
4820 spin_lock(&devices_kset->list_lock);
4821 /*
4822 * Walk the devices list backward, shutting down each in turn.
4823 * Beware that device unplug events may also start pulling
4824 * devices offline, even as the system is shutting down.
4825 */
4826 while (!list_empty(&devices_kset->list)) {
4827 dev = list_entry(devices_kset->list.prev, struct device,
4828 kobj.entry);
4829
4830 /*
4831 * hold reference count of device's parent to
4832 * prevent it from being freed because parent's
4833 * lock is to be held
4834 */
4835 parent = get_device(dev->parent);
4836 get_device(dev);
4837 /*
4838 * Make sure the device is off the kset list, in the
4839 * event that dev->*->shutdown() doesn't remove it.
4840 */
4841 list_del_init(&dev->kobj.entry);
4842 spin_unlock(&devices_kset->list_lock);
4843
4844 /* hold lock to avoid race with probe/release */
4845 if (parent)
4846 device_lock(parent);
4847 device_lock(dev);
4848
4849 /* Don't allow any more runtime suspends */
4850 pm_runtime_get_noresume(dev);
4851 pm_runtime_barrier(dev);
4852
4853 if (dev->class && dev->class->shutdown_pre) {
4854 if (initcall_debug)
4855 dev_info(dev, "shutdown_pre\n");
4856 dev->class->shutdown_pre(dev);
4857 }
4858 if (dev->bus && dev->bus->shutdown) {
4859 if (initcall_debug)
4860 dev_info(dev, "shutdown\n");
4861 dev->bus->shutdown(dev);
4862 } else if (dev->driver && dev->driver->shutdown) {
4863 if (initcall_debug)
4864 dev_info(dev, "shutdown\n");
4865 dev->driver->shutdown(dev);
4866 }
4867
4868 device_unlock(dev);
4869 if (parent)
4870 device_unlock(parent);
4871
4872 put_device(dev);
4873 put_device(parent);
4874
4875 spin_lock(&devices_kset->list_lock);
4876 }
4877 spin_unlock(&devices_kset->list_lock);
4878}
4879
4880/*
4881 * Device logging functions
4882 */
4883
4884#ifdef CONFIG_PRINTK
4885static void
4886set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4887{
4888 const char *subsys;
4889
4890 memset(dev_info, 0, sizeof(*dev_info));
4891
4892 if (dev->class)
4893 subsys = dev->class->name;
4894 else if (dev->bus)
4895 subsys = dev->bus->name;
4896 else
4897 return;
4898
4899 strscpy(dev_info->subsystem, subsys);
4900
4901 /*
4902 * Add device identifier DEVICE=:
4903 * b12:8 block dev_t
4904 * c127:3 char dev_t
4905 * n8 netdev ifindex
4906 * +sound:card0 subsystem:devname
4907 */
4908 if (MAJOR(dev->devt)) {
4909 char c;
4910
4911 if (strcmp(subsys, "block") == 0)
4912 c = 'b';
4913 else
4914 c = 'c';
4915
4916 snprintf(dev_info->device, sizeof(dev_info->device),
4917 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4918 } else if (strcmp(subsys, "net") == 0) {
4919 struct net_device *net = to_net_dev(dev);
4920
4921 snprintf(dev_info->device, sizeof(dev_info->device),
4922 "n%u", net->ifindex);
4923 } else {
4924 snprintf(dev_info->device, sizeof(dev_info->device),
4925 "+%s:%s", subsys, dev_name(dev));
4926 }
4927}
4928
4929int dev_vprintk_emit(int level, const struct device *dev,
4930 const char *fmt, va_list args)
4931{
4932 struct dev_printk_info dev_info;
4933
4934 set_dev_info(dev, &dev_info);
4935
4936 return vprintk_emit(0, level, &dev_info, fmt, args);
4937}
4938EXPORT_SYMBOL(dev_vprintk_emit);
4939
4940int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4941{
4942 va_list args;
4943 int r;
4944
4945 va_start(args, fmt);
4946
4947 r = dev_vprintk_emit(level, dev, fmt, args);
4948
4949 va_end(args);
4950
4951 return r;
4952}
4953EXPORT_SYMBOL(dev_printk_emit);
4954
4955static void __dev_printk(const char *level, const struct device *dev,
4956 struct va_format *vaf)
4957{
4958 if (dev)
4959 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4960 dev_driver_string(dev), dev_name(dev), vaf);
4961 else
4962 printk("%s(NULL device *): %pV", level, vaf);
4963}
4964
4965void _dev_printk(const char *level, const struct device *dev,
4966 const char *fmt, ...)
4967{
4968 struct va_format vaf;
4969 va_list args;
4970
4971 va_start(args, fmt);
4972
4973 vaf.fmt = fmt;
4974 vaf.va = &args;
4975
4976 __dev_printk(level, dev, &vaf);
4977
4978 va_end(args);
4979}
4980EXPORT_SYMBOL(_dev_printk);
4981
4982#define define_dev_printk_level(func, kern_level) \
4983void func(const struct device *dev, const char *fmt, ...) \
4984{ \
4985 struct va_format vaf; \
4986 va_list args; \
4987 \
4988 va_start(args, fmt); \
4989 \
4990 vaf.fmt = fmt; \
4991 vaf.va = &args; \
4992 \
4993 __dev_printk(kern_level, dev, &vaf); \
4994 \
4995 va_end(args); \
4996} \
4997EXPORT_SYMBOL(func);
4998
4999define_dev_printk_level(_dev_emerg, KERN_EMERG);
5000define_dev_printk_level(_dev_alert, KERN_ALERT);
5001define_dev_printk_level(_dev_crit, KERN_CRIT);
5002define_dev_printk_level(_dev_err, KERN_ERR);
5003define_dev_printk_level(_dev_warn, KERN_WARNING);
5004define_dev_printk_level(_dev_notice, KERN_NOTICE);
5005define_dev_printk_level(_dev_info, KERN_INFO);
5006
5007#endif
5008
5009static void __dev_probe_failed(const struct device *dev, int err, bool fatal,
5010 const char *fmt, va_list vargsp)
5011{
5012 struct va_format vaf;
5013 va_list vargs;
5014
5015 /*
5016 * On x86_64 and possibly on other architectures, va_list is actually a
5017 * size-1 array containing a structure. As a result, function parameter
5018 * vargsp decays from T[1] to T*, and &vargsp has type T** rather than
5019 * T(*)[1], which is expected by its assignment to vaf.va below.
5020 *
5021 * One standard way to solve this mess is by creating a copy in a local
5022 * variable of type va_list and then using a pointer to that local copy
5023 * instead, which is the approach employed here.
5024 */
5025 va_copy(vargs, vargsp);
5026
5027 vaf.fmt = fmt;
5028 vaf.va = &vargs;
5029
5030 switch (err) {
5031 case -EPROBE_DEFER:
5032 device_set_deferred_probe_reason(dev, &vaf);
5033 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
5034 break;
5035
5036 case -ENOMEM:
5037 /* Don't print anything on -ENOMEM, there's already enough output */
5038 break;
5039
5040 default:
5041 /* Log fatal final failures as errors, otherwise produce warnings */
5042 if (fatal)
5043 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
5044 else
5045 dev_warn(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
5046 break;
5047 }
5048
5049 va_end(vargs);
5050}
5051
5052/**
5053 * dev_err_probe - probe error check and log helper
5054 * @dev: the pointer to the struct device
5055 * @err: error value to test
5056 * @fmt: printf-style format string
5057 * @...: arguments as specified in the format string
5058 *
5059 * This helper implements common pattern present in probe functions for error
5060 * checking: print debug or error message depending if the error value is
5061 * -EPROBE_DEFER and propagate error upwards.
5062 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
5063 * checked later by reading devices_deferred debugfs attribute.
5064 * It replaces the following code sequence::
5065 *
5066 * if (err != -EPROBE_DEFER)
5067 * dev_err(dev, ...);
5068 * else
5069 * dev_dbg(dev, ...);
5070 * return err;
5071 *
5072 * with::
5073 *
5074 * return dev_err_probe(dev, err, ...);
5075 *
5076 * Using this helper in your probe function is totally fine even if @err
5077 * is known to never be -EPROBE_DEFER.
5078 * The benefit compared to a normal dev_err() is the standardized format
5079 * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
5080 * instead of "-35"), and having the error code returned allows more
5081 * compact error paths.
5082 *
5083 * Returns @err.
5084 */
5085int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
5086{
5087 va_list vargs;
5088
5089 va_start(vargs, fmt);
5090
5091 /* Use dev_err() for logging when err doesn't equal -EPROBE_DEFER */
5092 __dev_probe_failed(dev, err, true, fmt, vargs);
5093
5094 va_end(vargs);
5095
5096 return err;
5097}
5098EXPORT_SYMBOL_GPL(dev_err_probe);
5099
5100/**
5101 * dev_warn_probe - probe error check and log helper
5102 * @dev: the pointer to the struct device
5103 * @err: error value to test
5104 * @fmt: printf-style format string
5105 * @...: arguments as specified in the format string
5106 *
5107 * This helper implements common pattern present in probe functions for error
5108 * checking: print debug or warning message depending if the error value is
5109 * -EPROBE_DEFER and propagate error upwards.
5110 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
5111 * checked later by reading devices_deferred debugfs attribute.
5112 * It replaces the following code sequence::
5113 *
5114 * if (err != -EPROBE_DEFER)
5115 * dev_warn(dev, ...);
5116 * else
5117 * dev_dbg(dev, ...);
5118 * return err;
5119 *
5120 * with::
5121 *
5122 * return dev_warn_probe(dev, err, ...);
5123 *
5124 * Using this helper in your probe function is totally fine even if @err
5125 * is known to never be -EPROBE_DEFER.
5126 * The benefit compared to a normal dev_warn() is the standardized format
5127 * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
5128 * instead of "-35"), and having the error code returned allows more
5129 * compact error paths.
5130 *
5131 * Returns @err.
5132 */
5133int dev_warn_probe(const struct device *dev, int err, const char *fmt, ...)
5134{
5135 va_list vargs;
5136
5137 va_start(vargs, fmt);
5138
5139 /* Use dev_warn() for logging when err doesn't equal -EPROBE_DEFER */
5140 __dev_probe_failed(dev, err, false, fmt, vargs);
5141
5142 va_end(vargs);
5143
5144 return err;
5145}
5146EXPORT_SYMBOL_GPL(dev_warn_probe);
5147
5148static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
5149{
5150 return fwnode && !IS_ERR(fwnode->secondary);
5151}
5152
5153/**
5154 * set_primary_fwnode - Change the primary firmware node of a given device.
5155 * @dev: Device to handle.
5156 * @fwnode: New primary firmware node of the device.
5157 *
5158 * Set the device's firmware node pointer to @fwnode, but if a secondary
5159 * firmware node of the device is present, preserve it.
5160 *
5161 * Valid fwnode cases are:
5162 * - primary --> secondary --> -ENODEV
5163 * - primary --> NULL
5164 * - secondary --> -ENODEV
5165 * - NULL
5166 */
5167void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5168{
5169 struct device *parent = dev->parent;
5170 struct fwnode_handle *fn = dev->fwnode;
5171
5172 if (fwnode) {
5173 if (fwnode_is_primary(fn))
5174 fn = fn->secondary;
5175
5176 if (fn) {
5177 WARN_ON(fwnode->secondary);
5178 fwnode->secondary = fn;
5179 }
5180 dev->fwnode = fwnode;
5181 } else {
5182 if (fwnode_is_primary(fn)) {
5183 dev->fwnode = fn->secondary;
5184
5185 /* Skip nullifying fn->secondary if the primary is shared */
5186 if (parent && fn == parent->fwnode)
5187 return;
5188
5189 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
5190 fn->secondary = NULL;
5191 } else {
5192 dev->fwnode = NULL;
5193 }
5194 }
5195}
5196EXPORT_SYMBOL_GPL(set_primary_fwnode);
5197
5198/**
5199 * set_secondary_fwnode - Change the secondary firmware node of a given device.
5200 * @dev: Device to handle.
5201 * @fwnode: New secondary firmware node of the device.
5202 *
5203 * If a primary firmware node of the device is present, set its secondary
5204 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
5205 * @fwnode.
5206 */
5207void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5208{
5209 if (fwnode)
5210 fwnode->secondary = ERR_PTR(-ENODEV);
5211
5212 if (fwnode_is_primary(dev->fwnode))
5213 dev->fwnode->secondary = fwnode;
5214 else
5215 dev->fwnode = fwnode;
5216}
5217EXPORT_SYMBOL_GPL(set_secondary_fwnode);
5218
5219/**
5220 * device_set_of_node_from_dev - reuse device-tree node of another device
5221 * @dev: device whose device-tree node is being set
5222 * @dev2: device whose device-tree node is being reused
5223 *
5224 * Takes another reference to the new device-tree node after first dropping
5225 * any reference held to the old node.
5226 */
5227void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
5228{
5229 of_node_put(dev->of_node);
5230 dev->of_node = of_node_get(dev2->of_node);
5231 dev->of_node_reused = true;
5232}
5233EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
5234
5235void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
5236{
5237 dev->fwnode = fwnode;
5238 dev->of_node = to_of_node(fwnode);
5239}
5240EXPORT_SYMBOL_GPL(device_set_node);
5241
5242int device_match_name(struct device *dev, const void *name)
5243{
5244 return sysfs_streq(dev_name(dev), name);
5245}
5246EXPORT_SYMBOL_GPL(device_match_name);
5247
5248int device_match_of_node(struct device *dev, const void *np)
5249{
5250 return dev->of_node == np;
5251}
5252EXPORT_SYMBOL_GPL(device_match_of_node);
5253
5254int device_match_fwnode(struct device *dev, const void *fwnode)
5255{
5256 return dev_fwnode(dev) == fwnode;
5257}
5258EXPORT_SYMBOL_GPL(device_match_fwnode);
5259
5260int device_match_devt(struct device *dev, const void *pdevt)
5261{
5262 return dev->devt == *(dev_t *)pdevt;
5263}
5264EXPORT_SYMBOL_GPL(device_match_devt);
5265
5266int device_match_acpi_dev(struct device *dev, const void *adev)
5267{
5268 return ACPI_COMPANION(dev) == adev;
5269}
5270EXPORT_SYMBOL(device_match_acpi_dev);
5271
5272int device_match_acpi_handle(struct device *dev, const void *handle)
5273{
5274 return ACPI_HANDLE(dev) == handle;
5275}
5276EXPORT_SYMBOL(device_match_acpi_handle);
5277
5278int device_match_any(struct device *dev, const void *unused)
5279{
5280 return 1;
5281}
5282EXPORT_SYMBOL_GPL(device_match_any);