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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/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/module.h>
18#include <linux/slab.h>
19#include <linux/string.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/genhd.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/sysfs.h>
30
31#include "base.h"
32#include "power/power.h"
33
34#ifdef CONFIG_SYSFS_DEPRECATED
35#ifdef CONFIG_SYSFS_DEPRECATED_V2
36long sysfs_deprecated = 1;
37#else
38long sysfs_deprecated = 0;
39#endif
40static int __init sysfs_deprecated_setup(char *arg)
41{
42 return kstrtol(arg, 10, &sysfs_deprecated);
43}
44early_param("sysfs.deprecated", sysfs_deprecated_setup);
45#endif
46
47/* Device links support. */
48static LIST_HEAD(wait_for_suppliers);
49static DEFINE_MUTEX(wfs_lock);
50static LIST_HEAD(deferred_sync);
51static unsigned int defer_sync_state_count = 1;
52static unsigned int defer_fw_devlink_count;
53static LIST_HEAD(deferred_fw_devlink);
54static DEFINE_MUTEX(defer_fw_devlink_lock);
55static bool fw_devlink_is_permissive(void);
56
57#ifdef CONFIG_SRCU
58static DEFINE_MUTEX(device_links_lock);
59DEFINE_STATIC_SRCU(device_links_srcu);
60
61static inline void device_links_write_lock(void)
62{
63 mutex_lock(&device_links_lock);
64}
65
66static inline void device_links_write_unlock(void)
67{
68 mutex_unlock(&device_links_lock);
69}
70
71int device_links_read_lock(void) __acquires(&device_links_srcu)
72{
73 return srcu_read_lock(&device_links_srcu);
74}
75
76void device_links_read_unlock(int idx) __releases(&device_links_srcu)
77{
78 srcu_read_unlock(&device_links_srcu, idx);
79}
80
81int device_links_read_lock_held(void)
82{
83 return srcu_read_lock_held(&device_links_srcu);
84}
85#else /* !CONFIG_SRCU */
86static DECLARE_RWSEM(device_links_lock);
87
88static inline void device_links_write_lock(void)
89{
90 down_write(&device_links_lock);
91}
92
93static inline void device_links_write_unlock(void)
94{
95 up_write(&device_links_lock);
96}
97
98int device_links_read_lock(void)
99{
100 down_read(&device_links_lock);
101 return 0;
102}
103
104void device_links_read_unlock(int not_used)
105{
106 up_read(&device_links_lock);
107}
108
109#ifdef CONFIG_DEBUG_LOCK_ALLOC
110int device_links_read_lock_held(void)
111{
112 return lockdep_is_held(&device_links_lock);
113}
114#endif
115#endif /* !CONFIG_SRCU */
116
117/**
118 * device_is_dependent - Check if one device depends on another one
119 * @dev: Device to check dependencies for.
120 * @target: Device to check against.
121 *
122 * Check if @target depends on @dev or any device dependent on it (its child or
123 * its consumer etc). Return 1 if that is the case or 0 otherwise.
124 */
125int device_is_dependent(struct device *dev, void *target)
126{
127 struct device_link *link;
128 int ret;
129
130 if (dev == target)
131 return 1;
132
133 ret = device_for_each_child(dev, target, device_is_dependent);
134 if (ret)
135 return ret;
136
137 list_for_each_entry(link, &dev->links.consumers, s_node) {
138 if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
139 continue;
140
141 if (link->consumer == target)
142 return 1;
143
144 ret = device_is_dependent(link->consumer, target);
145 if (ret)
146 break;
147 }
148 return ret;
149}
150
151static void device_link_init_status(struct device_link *link,
152 struct device *consumer,
153 struct device *supplier)
154{
155 switch (supplier->links.status) {
156 case DL_DEV_PROBING:
157 switch (consumer->links.status) {
158 case DL_DEV_PROBING:
159 /*
160 * A consumer driver can create a link to a supplier
161 * that has not completed its probing yet as long as it
162 * knows that the supplier is already functional (for
163 * example, it has just acquired some resources from the
164 * supplier).
165 */
166 link->status = DL_STATE_CONSUMER_PROBE;
167 break;
168 default:
169 link->status = DL_STATE_DORMANT;
170 break;
171 }
172 break;
173 case DL_DEV_DRIVER_BOUND:
174 switch (consumer->links.status) {
175 case DL_DEV_PROBING:
176 link->status = DL_STATE_CONSUMER_PROBE;
177 break;
178 case DL_DEV_DRIVER_BOUND:
179 link->status = DL_STATE_ACTIVE;
180 break;
181 default:
182 link->status = DL_STATE_AVAILABLE;
183 break;
184 }
185 break;
186 case DL_DEV_UNBINDING:
187 link->status = DL_STATE_SUPPLIER_UNBIND;
188 break;
189 default:
190 link->status = DL_STATE_DORMANT;
191 break;
192 }
193}
194
195static int device_reorder_to_tail(struct device *dev, void *not_used)
196{
197 struct device_link *link;
198
199 /*
200 * Devices that have not been registered yet will be put to the ends
201 * of the lists during the registration, so skip them here.
202 */
203 if (device_is_registered(dev))
204 devices_kset_move_last(dev);
205
206 if (device_pm_initialized(dev))
207 device_pm_move_last(dev);
208
209 device_for_each_child(dev, NULL, device_reorder_to_tail);
210 list_for_each_entry(link, &dev->links.consumers, s_node) {
211 if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
212 continue;
213 device_reorder_to_tail(link->consumer, NULL);
214 }
215
216 return 0;
217}
218
219/**
220 * device_pm_move_to_tail - Move set of devices to the end of device lists
221 * @dev: Device to move
222 *
223 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
224 *
225 * It moves the @dev along with all of its children and all of its consumers
226 * to the ends of the device_kset and dpm_list, recursively.
227 */
228void device_pm_move_to_tail(struct device *dev)
229{
230 int idx;
231
232 idx = device_links_read_lock();
233 device_pm_lock();
234 device_reorder_to_tail(dev, NULL);
235 device_pm_unlock();
236 device_links_read_unlock(idx);
237}
238
239#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
240
241static ssize_t status_show(struct device *dev,
242 struct device_attribute *attr, char *buf)
243{
244 char *status;
245
246 switch (to_devlink(dev)->status) {
247 case DL_STATE_NONE:
248 status = "not tracked"; break;
249 case DL_STATE_DORMANT:
250 status = "dormant"; break;
251 case DL_STATE_AVAILABLE:
252 status = "available"; break;
253 case DL_STATE_CONSUMER_PROBE:
254 status = "consumer probing"; break;
255 case DL_STATE_ACTIVE:
256 status = "active"; break;
257 case DL_STATE_SUPPLIER_UNBIND:
258 status = "supplier unbinding"; break;
259 default:
260 status = "unknown"; break;
261 }
262 return sprintf(buf, "%s\n", status);
263}
264static DEVICE_ATTR_RO(status);
265
266static ssize_t auto_remove_on_show(struct device *dev,
267 struct device_attribute *attr, char *buf)
268{
269 struct device_link *link = to_devlink(dev);
270 char *str;
271
272 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
273 str = "supplier unbind";
274 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
275 str = "consumer unbind";
276 else
277 str = "never";
278
279 return sprintf(buf, "%s\n", str);
280}
281static DEVICE_ATTR_RO(auto_remove_on);
282
283static ssize_t runtime_pm_show(struct device *dev,
284 struct device_attribute *attr, char *buf)
285{
286 struct device_link *link = to_devlink(dev);
287
288 return sprintf(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
289}
290static DEVICE_ATTR_RO(runtime_pm);
291
292static ssize_t sync_state_only_show(struct device *dev,
293 struct device_attribute *attr, char *buf)
294{
295 struct device_link *link = to_devlink(dev);
296
297 return sprintf(buf, "%d\n", !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
298}
299static DEVICE_ATTR_RO(sync_state_only);
300
301static struct attribute *devlink_attrs[] = {
302 &dev_attr_status.attr,
303 &dev_attr_auto_remove_on.attr,
304 &dev_attr_runtime_pm.attr,
305 &dev_attr_sync_state_only.attr,
306 NULL,
307};
308ATTRIBUTE_GROUPS(devlink);
309
310static void device_link_free(struct device_link *link)
311{
312 while (refcount_dec_not_one(&link->rpm_active))
313 pm_runtime_put(link->supplier);
314
315 put_device(link->consumer);
316 put_device(link->supplier);
317 kfree(link);
318}
319
320#ifdef CONFIG_SRCU
321static void __device_link_free_srcu(struct rcu_head *rhead)
322{
323 device_link_free(container_of(rhead, struct device_link, rcu_head));
324}
325
326static void devlink_dev_release(struct device *dev)
327{
328 struct device_link *link = to_devlink(dev);
329
330 call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
331}
332#else
333static void devlink_dev_release(struct device *dev)
334{
335 device_link_free(to_devlink(dev));
336}
337#endif
338
339static struct class devlink_class = {
340 .name = "devlink",
341 .owner = THIS_MODULE,
342 .dev_groups = devlink_groups,
343 .dev_release = devlink_dev_release,
344};
345
346static int devlink_add_symlinks(struct device *dev,
347 struct class_interface *class_intf)
348{
349 int ret;
350 size_t len;
351 struct device_link *link = to_devlink(dev);
352 struct device *sup = link->supplier;
353 struct device *con = link->consumer;
354 char *buf;
355
356 len = max(strlen(dev_name(sup)), strlen(dev_name(con)));
357 len += strlen("supplier:") + 1;
358 buf = kzalloc(len, GFP_KERNEL);
359 if (!buf)
360 return -ENOMEM;
361
362 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
363 if (ret)
364 goto out;
365
366 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
367 if (ret)
368 goto err_con;
369
370 snprintf(buf, len, "consumer:%s", dev_name(con));
371 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
372 if (ret)
373 goto err_con_dev;
374
375 snprintf(buf, len, "supplier:%s", dev_name(sup));
376 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
377 if (ret)
378 goto err_sup_dev;
379
380 goto out;
381
382err_sup_dev:
383 snprintf(buf, len, "consumer:%s", dev_name(con));
384 sysfs_remove_link(&sup->kobj, buf);
385err_con_dev:
386 sysfs_remove_link(&link->link_dev.kobj, "consumer");
387err_con:
388 sysfs_remove_link(&link->link_dev.kobj, "supplier");
389out:
390 kfree(buf);
391 return ret;
392}
393
394static void devlink_remove_symlinks(struct device *dev,
395 struct class_interface *class_intf)
396{
397 struct device_link *link = to_devlink(dev);
398 size_t len;
399 struct device *sup = link->supplier;
400 struct device *con = link->consumer;
401 char *buf;
402
403 sysfs_remove_link(&link->link_dev.kobj, "consumer");
404 sysfs_remove_link(&link->link_dev.kobj, "supplier");
405
406 len = max(strlen(dev_name(sup)), strlen(dev_name(con)));
407 len += strlen("supplier:") + 1;
408 buf = kzalloc(len, GFP_KERNEL);
409 if (!buf) {
410 WARN(1, "Unable to properly free device link symlinks!\n");
411 return;
412 }
413
414 snprintf(buf, len, "supplier:%s", dev_name(sup));
415 sysfs_remove_link(&con->kobj, buf);
416 snprintf(buf, len, "consumer:%s", dev_name(con));
417 sysfs_remove_link(&sup->kobj, buf);
418 kfree(buf);
419}
420
421static struct class_interface devlink_class_intf = {
422 .class = &devlink_class,
423 .add_dev = devlink_add_symlinks,
424 .remove_dev = devlink_remove_symlinks,
425};
426
427static int __init devlink_class_init(void)
428{
429 int ret;
430
431 ret = class_register(&devlink_class);
432 if (ret)
433 return ret;
434
435 ret = class_interface_register(&devlink_class_intf);
436 if (ret)
437 class_unregister(&devlink_class);
438
439 return ret;
440}
441postcore_initcall(devlink_class_init);
442
443#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
444 DL_FLAG_AUTOREMOVE_SUPPLIER | \
445 DL_FLAG_AUTOPROBE_CONSUMER | \
446 DL_FLAG_SYNC_STATE_ONLY)
447
448#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
449 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
450
451/**
452 * device_link_add - Create a link between two devices.
453 * @consumer: Consumer end of the link.
454 * @supplier: Supplier end of the link.
455 * @flags: Link flags.
456 *
457 * The caller is responsible for the proper synchronization of the link creation
458 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
459 * runtime PM framework to take the link into account. Second, if the
460 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
461 * be forced into the active metastate and reference-counted upon the creation
462 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
463 * ignored.
464 *
465 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
466 * expected to release the link returned by it directly with the help of either
467 * device_link_del() or device_link_remove().
468 *
469 * If that flag is not set, however, the caller of this function is handing the
470 * management of the link over to the driver core entirely and its return value
471 * can only be used to check whether or not the link is present. In that case,
472 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
473 * flags can be used to indicate to the driver core when the link can be safely
474 * deleted. Namely, setting one of them in @flags indicates to the driver core
475 * that the link is not going to be used (by the given caller of this function)
476 * after unbinding the consumer or supplier driver, respectively, from its
477 * device, so the link can be deleted at that point. If none of them is set,
478 * the link will be maintained until one of the devices pointed to by it (either
479 * the consumer or the supplier) is unregistered.
480 *
481 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
482 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
483 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
484 * be used to request the driver core to automaticall probe for a consmer
485 * driver after successfully binding a driver to the supplier device.
486 *
487 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
488 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
489 * the same time is invalid and will cause NULL to be returned upfront.
490 * However, if a device link between the given @consumer and @supplier pair
491 * exists already when this function is called for them, the existing link will
492 * be returned regardless of its current type and status (the link's flags may
493 * be modified then). The caller of this function is then expected to treat
494 * the link as though it has just been created, so (in particular) if
495 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
496 * explicitly when not needed any more (as stated above).
497 *
498 * A side effect of the link creation is re-ordering of dpm_list and the
499 * devices_kset list by moving the consumer device and all devices depending
500 * on it to the ends of these lists (that does not happen to devices that have
501 * not been registered when this function is called).
502 *
503 * The supplier device is required to be registered when this function is called
504 * and NULL will be returned if that is not the case. The consumer device need
505 * not be registered, however.
506 */
507struct device_link *device_link_add(struct device *consumer,
508 struct device *supplier, u32 flags)
509{
510 struct device_link *link;
511
512 if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS ||
513 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
514 (flags & DL_FLAG_SYNC_STATE_ONLY &&
515 flags != DL_FLAG_SYNC_STATE_ONLY) ||
516 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
517 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
518 DL_FLAG_AUTOREMOVE_SUPPLIER)))
519 return NULL;
520
521 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
522 if (pm_runtime_get_sync(supplier) < 0) {
523 pm_runtime_put_noidle(supplier);
524 return NULL;
525 }
526 }
527
528 if (!(flags & DL_FLAG_STATELESS))
529 flags |= DL_FLAG_MANAGED;
530
531 device_links_write_lock();
532 device_pm_lock();
533
534 /*
535 * If the supplier has not been fully registered yet or there is a
536 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
537 * the supplier already in the graph, return NULL. If the link is a
538 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
539 * because it only affects sync_state() callbacks.
540 */
541 if (!device_pm_initialized(supplier)
542 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
543 device_is_dependent(consumer, supplier))) {
544 link = NULL;
545 goto out;
546 }
547
548 /*
549 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
550 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
551 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
552 */
553 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
554 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
555
556 list_for_each_entry(link, &supplier->links.consumers, s_node) {
557 if (link->consumer != consumer)
558 continue;
559
560 if (flags & DL_FLAG_PM_RUNTIME) {
561 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
562 pm_runtime_new_link(consumer);
563 link->flags |= DL_FLAG_PM_RUNTIME;
564 }
565 if (flags & DL_FLAG_RPM_ACTIVE)
566 refcount_inc(&link->rpm_active);
567 }
568
569 if (flags & DL_FLAG_STATELESS) {
570 kref_get(&link->kref);
571 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
572 !(link->flags & DL_FLAG_STATELESS)) {
573 link->flags |= DL_FLAG_STATELESS;
574 goto reorder;
575 } else {
576 link->flags |= DL_FLAG_STATELESS;
577 goto out;
578 }
579 }
580
581 /*
582 * If the life time of the link following from the new flags is
583 * longer than indicated by the flags of the existing link,
584 * update the existing link to stay around longer.
585 */
586 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
587 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
588 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
589 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
590 }
591 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
592 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
593 DL_FLAG_AUTOREMOVE_SUPPLIER);
594 }
595 if (!(link->flags & DL_FLAG_MANAGED)) {
596 kref_get(&link->kref);
597 link->flags |= DL_FLAG_MANAGED;
598 device_link_init_status(link, consumer, supplier);
599 }
600 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
601 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
602 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
603 goto reorder;
604 }
605
606 goto out;
607 }
608
609 link = kzalloc(sizeof(*link), GFP_KERNEL);
610 if (!link)
611 goto out;
612
613 refcount_set(&link->rpm_active, 1);
614
615 get_device(supplier);
616 link->supplier = supplier;
617 INIT_LIST_HEAD(&link->s_node);
618 get_device(consumer);
619 link->consumer = consumer;
620 INIT_LIST_HEAD(&link->c_node);
621 link->flags = flags;
622 kref_init(&link->kref);
623
624 link->link_dev.class = &devlink_class;
625 device_set_pm_not_required(&link->link_dev);
626 dev_set_name(&link->link_dev, "%s--%s",
627 dev_name(supplier), dev_name(consumer));
628 if (device_register(&link->link_dev)) {
629 put_device(consumer);
630 put_device(supplier);
631 kfree(link);
632 link = NULL;
633 goto out;
634 }
635
636 if (flags & DL_FLAG_PM_RUNTIME) {
637 if (flags & DL_FLAG_RPM_ACTIVE)
638 refcount_inc(&link->rpm_active);
639
640 pm_runtime_new_link(consumer);
641 }
642
643 /* Determine the initial link state. */
644 if (flags & DL_FLAG_STATELESS)
645 link->status = DL_STATE_NONE;
646 else
647 device_link_init_status(link, consumer, supplier);
648
649 /*
650 * Some callers expect the link creation during consumer driver probe to
651 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
652 */
653 if (link->status == DL_STATE_CONSUMER_PROBE &&
654 flags & DL_FLAG_PM_RUNTIME)
655 pm_runtime_resume(supplier);
656
657 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
658 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
659
660 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
661 dev_dbg(consumer,
662 "Linked as a sync state only consumer to %s\n",
663 dev_name(supplier));
664 goto out;
665 }
666
667reorder:
668 /*
669 * Move the consumer and all of the devices depending on it to the end
670 * of dpm_list and the devices_kset list.
671 *
672 * It is necessary to hold dpm_list locked throughout all that or else
673 * we may end up suspending with a wrong ordering of it.
674 */
675 device_reorder_to_tail(consumer, NULL);
676
677 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
678
679out:
680 device_pm_unlock();
681 device_links_write_unlock();
682
683 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
684 pm_runtime_put(supplier);
685
686 return link;
687}
688EXPORT_SYMBOL_GPL(device_link_add);
689
690/**
691 * device_link_wait_for_supplier - Add device to wait_for_suppliers list
692 * @consumer: Consumer device
693 *
694 * Marks the @consumer device as waiting for suppliers to become available by
695 * adding it to the wait_for_suppliers list. The consumer device will never be
696 * probed until it's removed from the wait_for_suppliers list.
697 *
698 * The caller is responsible for adding the links to the supplier devices once
699 * they are available and removing the @consumer device from the
700 * wait_for_suppliers list once links to all the suppliers have been created.
701 *
702 * This function is NOT meant to be called from the probe function of the
703 * consumer but rather from code that creates/adds the consumer device.
704 */
705static void device_link_wait_for_supplier(struct device *consumer,
706 bool need_for_probe)
707{
708 mutex_lock(&wfs_lock);
709 list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers);
710 consumer->links.need_for_probe = need_for_probe;
711 mutex_unlock(&wfs_lock);
712}
713
714static void device_link_wait_for_mandatory_supplier(struct device *consumer)
715{
716 device_link_wait_for_supplier(consumer, true);
717}
718
719static void device_link_wait_for_optional_supplier(struct device *consumer)
720{
721 device_link_wait_for_supplier(consumer, false);
722}
723
724/**
725 * device_link_add_missing_supplier_links - Add links from consumer devices to
726 * supplier devices, leaving any
727 * consumer with inactive suppliers on
728 * the wait_for_suppliers list
729 *
730 * Loops through all consumers waiting on suppliers and tries to add all their
731 * supplier links. If that succeeds, the consumer device is removed from
732 * wait_for_suppliers list. Otherwise, they are left in the wait_for_suppliers
733 * list. Devices left on the wait_for_suppliers list will not be probed.
734 *
735 * The fwnode add_links callback is expected to return 0 if it has found and
736 * added all the supplier links for the consumer device. It should return an
737 * error if it isn't able to do so.
738 *
739 * The caller of device_link_wait_for_supplier() is expected to call this once
740 * it's aware of potential suppliers becoming available.
741 */
742static void device_link_add_missing_supplier_links(void)
743{
744 struct device *dev, *tmp;
745
746 mutex_lock(&wfs_lock);
747 list_for_each_entry_safe(dev, tmp, &wait_for_suppliers,
748 links.needs_suppliers) {
749 int ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
750 if (!ret)
751 list_del_init(&dev->links.needs_suppliers);
752 else if (ret != -ENODEV || fw_devlink_is_permissive())
753 dev->links.need_for_probe = false;
754 }
755 mutex_unlock(&wfs_lock);
756}
757
758#ifdef CONFIG_SRCU
759static void __device_link_del(struct kref *kref)
760{
761 struct device_link *link = container_of(kref, struct device_link, kref);
762
763 dev_dbg(link->consumer, "Dropping the link to %s\n",
764 dev_name(link->supplier));
765
766 if (link->flags & DL_FLAG_PM_RUNTIME)
767 pm_runtime_drop_link(link->consumer);
768
769 list_del_rcu(&link->s_node);
770 list_del_rcu(&link->c_node);
771 device_unregister(&link->link_dev);
772}
773#else /* !CONFIG_SRCU */
774static void __device_link_del(struct kref *kref)
775{
776 struct device_link *link = container_of(kref, struct device_link, kref);
777
778 dev_info(link->consumer, "Dropping the link to %s\n",
779 dev_name(link->supplier));
780
781 if (link->flags & DL_FLAG_PM_RUNTIME)
782 pm_runtime_drop_link(link->consumer);
783
784 list_del(&link->s_node);
785 list_del(&link->c_node);
786 device_unregister(&link->link_dev);
787}
788#endif /* !CONFIG_SRCU */
789
790static void device_link_put_kref(struct device_link *link)
791{
792 if (link->flags & DL_FLAG_STATELESS)
793 kref_put(&link->kref, __device_link_del);
794 else
795 WARN(1, "Unable to drop a managed device link reference\n");
796}
797
798/**
799 * device_link_del - Delete a stateless link between two devices.
800 * @link: Device link to delete.
801 *
802 * The caller must ensure proper synchronization of this function with runtime
803 * PM. If the link was added multiple times, it needs to be deleted as often.
804 * Care is required for hotplugged devices: Their links are purged on removal
805 * and calling device_link_del() is then no longer allowed.
806 */
807void device_link_del(struct device_link *link)
808{
809 device_links_write_lock();
810 device_link_put_kref(link);
811 device_links_write_unlock();
812}
813EXPORT_SYMBOL_GPL(device_link_del);
814
815/**
816 * device_link_remove - Delete a stateless link between two devices.
817 * @consumer: Consumer end of the link.
818 * @supplier: Supplier end of the link.
819 *
820 * The caller must ensure proper synchronization of this function with runtime
821 * PM.
822 */
823void device_link_remove(void *consumer, struct device *supplier)
824{
825 struct device_link *link;
826
827 if (WARN_ON(consumer == supplier))
828 return;
829
830 device_links_write_lock();
831
832 list_for_each_entry(link, &supplier->links.consumers, s_node) {
833 if (link->consumer == consumer) {
834 device_link_put_kref(link);
835 break;
836 }
837 }
838
839 device_links_write_unlock();
840}
841EXPORT_SYMBOL_GPL(device_link_remove);
842
843static void device_links_missing_supplier(struct device *dev)
844{
845 struct device_link *link;
846
847 list_for_each_entry(link, &dev->links.suppliers, c_node) {
848 if (link->status != DL_STATE_CONSUMER_PROBE)
849 continue;
850
851 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
852 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
853 } else {
854 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
855 WRITE_ONCE(link->status, DL_STATE_DORMANT);
856 }
857 }
858}
859
860/**
861 * device_links_check_suppliers - Check presence of supplier drivers.
862 * @dev: Consumer device.
863 *
864 * Check links from this device to any suppliers. Walk the list of the device's
865 * links to suppliers and see if all of them are available. If not, simply
866 * return -EPROBE_DEFER.
867 *
868 * We need to guarantee that the supplier will not go away after the check has
869 * been positive here. It only can go away in __device_release_driver() and
870 * that function checks the device's links to consumers. This means we need to
871 * mark the link as "consumer probe in progress" to make the supplier removal
872 * wait for us to complete (or bad things may happen).
873 *
874 * Links without the DL_FLAG_MANAGED flag set are ignored.
875 */
876int device_links_check_suppliers(struct device *dev)
877{
878 struct device_link *link;
879 int ret = 0;
880
881 /*
882 * Device waiting for supplier to become available is not allowed to
883 * probe.
884 */
885 mutex_lock(&wfs_lock);
886 if (!list_empty(&dev->links.needs_suppliers) &&
887 dev->links.need_for_probe) {
888 mutex_unlock(&wfs_lock);
889 return -EPROBE_DEFER;
890 }
891 mutex_unlock(&wfs_lock);
892
893 device_links_write_lock();
894
895 list_for_each_entry(link, &dev->links.suppliers, c_node) {
896 if (!(link->flags & DL_FLAG_MANAGED))
897 continue;
898
899 if (link->status != DL_STATE_AVAILABLE &&
900 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
901 device_links_missing_supplier(dev);
902 ret = -EPROBE_DEFER;
903 break;
904 }
905 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
906 }
907 dev->links.status = DL_DEV_PROBING;
908
909 device_links_write_unlock();
910 return ret;
911}
912
913/**
914 * __device_links_queue_sync_state - Queue a device for sync_state() callback
915 * @dev: Device to call sync_state() on
916 * @list: List head to queue the @dev on
917 *
918 * Queues a device for a sync_state() callback when the device links write lock
919 * isn't held. This allows the sync_state() execution flow to use device links
920 * APIs. The caller must ensure this function is called with
921 * device_links_write_lock() held.
922 *
923 * This function does a get_device() to make sure the device is not freed while
924 * on this list.
925 *
926 * So the caller must also ensure that device_links_flush_sync_list() is called
927 * as soon as the caller releases device_links_write_lock(). This is necessary
928 * to make sure the sync_state() is called in a timely fashion and the
929 * put_device() is called on this device.
930 */
931static void __device_links_queue_sync_state(struct device *dev,
932 struct list_head *list)
933{
934 struct device_link *link;
935
936 if (!dev_has_sync_state(dev))
937 return;
938 if (dev->state_synced)
939 return;
940
941 list_for_each_entry(link, &dev->links.consumers, s_node) {
942 if (!(link->flags & DL_FLAG_MANAGED))
943 continue;
944 if (link->status != DL_STATE_ACTIVE)
945 return;
946 }
947
948 /*
949 * Set the flag here to avoid adding the same device to a list more
950 * than once. This can happen if new consumers get added to the device
951 * and probed before the list is flushed.
952 */
953 dev->state_synced = true;
954
955 if (WARN_ON(!list_empty(&dev->links.defer_hook)))
956 return;
957
958 get_device(dev);
959 list_add_tail(&dev->links.defer_hook, list);
960}
961
962/**
963 * device_links_flush_sync_list - Call sync_state() on a list of devices
964 * @list: List of devices to call sync_state() on
965 * @dont_lock_dev: Device for which lock is already held by the caller
966 *
967 * Calls sync_state() on all the devices that have been queued for it. This
968 * function is used in conjunction with __device_links_queue_sync_state(). The
969 * @dont_lock_dev parameter is useful when this function is called from a
970 * context where a device lock is already held.
971 */
972static void device_links_flush_sync_list(struct list_head *list,
973 struct device *dont_lock_dev)
974{
975 struct device *dev, *tmp;
976
977 list_for_each_entry_safe(dev, tmp, list, links.defer_hook) {
978 list_del_init(&dev->links.defer_hook);
979
980 if (dev != dont_lock_dev)
981 device_lock(dev);
982
983 if (dev->bus->sync_state)
984 dev->bus->sync_state(dev);
985 else if (dev->driver && dev->driver->sync_state)
986 dev->driver->sync_state(dev);
987
988 if (dev != dont_lock_dev)
989 device_unlock(dev);
990
991 put_device(dev);
992 }
993}
994
995void device_links_supplier_sync_state_pause(void)
996{
997 device_links_write_lock();
998 defer_sync_state_count++;
999 device_links_write_unlock();
1000}
1001
1002void device_links_supplier_sync_state_resume(void)
1003{
1004 struct device *dev, *tmp;
1005 LIST_HEAD(sync_list);
1006
1007 device_links_write_lock();
1008 if (!defer_sync_state_count) {
1009 WARN(true, "Unmatched sync_state pause/resume!");
1010 goto out;
1011 }
1012 defer_sync_state_count--;
1013 if (defer_sync_state_count)
1014 goto out;
1015
1016 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_hook) {
1017 /*
1018 * Delete from deferred_sync list before queuing it to
1019 * sync_list because defer_hook is used for both lists.
1020 */
1021 list_del_init(&dev->links.defer_hook);
1022 __device_links_queue_sync_state(dev, &sync_list);
1023 }
1024out:
1025 device_links_write_unlock();
1026
1027 device_links_flush_sync_list(&sync_list, NULL);
1028}
1029
1030static int sync_state_resume_initcall(void)
1031{
1032 device_links_supplier_sync_state_resume();
1033 return 0;
1034}
1035late_initcall(sync_state_resume_initcall);
1036
1037static void __device_links_supplier_defer_sync(struct device *sup)
1038{
1039 if (list_empty(&sup->links.defer_hook) && dev_has_sync_state(sup))
1040 list_add_tail(&sup->links.defer_hook, &deferred_sync);
1041}
1042
1043static void device_link_drop_managed(struct device_link *link)
1044{
1045 link->flags &= ~DL_FLAG_MANAGED;
1046 WRITE_ONCE(link->status, DL_STATE_NONE);
1047 kref_put(&link->kref, __device_link_del);
1048}
1049
1050static ssize_t waiting_for_supplier_show(struct device *dev,
1051 struct device_attribute *attr,
1052 char *buf)
1053{
1054 bool val;
1055
1056 device_lock(dev);
1057 mutex_lock(&wfs_lock);
1058 val = !list_empty(&dev->links.needs_suppliers)
1059 && dev->links.need_for_probe;
1060 mutex_unlock(&wfs_lock);
1061 device_unlock(dev);
1062 return sprintf(buf, "%u\n", val);
1063}
1064static DEVICE_ATTR_RO(waiting_for_supplier);
1065
1066/**
1067 * device_links_driver_bound - Update device links after probing its driver.
1068 * @dev: Device to update the links for.
1069 *
1070 * The probe has been successful, so update links from this device to any
1071 * consumers by changing their status to "available".
1072 *
1073 * Also change the status of @dev's links to suppliers to "active".
1074 *
1075 * Links without the DL_FLAG_MANAGED flag set are ignored.
1076 */
1077void device_links_driver_bound(struct device *dev)
1078{
1079 struct device_link *link, *ln;
1080 LIST_HEAD(sync_list);
1081
1082 /*
1083 * If a device probes successfully, it's expected to have created all
1084 * the device links it needs to or make new device links as it needs
1085 * them. So, it no longer needs to wait on any suppliers.
1086 */
1087 mutex_lock(&wfs_lock);
1088 list_del_init(&dev->links.needs_suppliers);
1089 mutex_unlock(&wfs_lock);
1090 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1091
1092 device_links_write_lock();
1093
1094 list_for_each_entry(link, &dev->links.consumers, s_node) {
1095 if (!(link->flags & DL_FLAG_MANAGED))
1096 continue;
1097
1098 /*
1099 * Links created during consumer probe may be in the "consumer
1100 * probe" state to start with if the supplier is still probing
1101 * when they are created and they may become "active" if the
1102 * consumer probe returns first. Skip them here.
1103 */
1104 if (link->status == DL_STATE_CONSUMER_PROBE ||
1105 link->status == DL_STATE_ACTIVE)
1106 continue;
1107
1108 WARN_ON(link->status != DL_STATE_DORMANT);
1109 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1110
1111 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1112 driver_deferred_probe_add(link->consumer);
1113 }
1114
1115 if (defer_sync_state_count)
1116 __device_links_supplier_defer_sync(dev);
1117 else
1118 __device_links_queue_sync_state(dev, &sync_list);
1119
1120 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1121 struct device *supplier;
1122
1123 if (!(link->flags & DL_FLAG_MANAGED))
1124 continue;
1125
1126 supplier = link->supplier;
1127 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1128 /*
1129 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1130 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1131 * save to drop the managed link completely.
1132 */
1133 device_link_drop_managed(link);
1134 } else {
1135 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1136 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1137 }
1138
1139 /*
1140 * This needs to be done even for the deleted
1141 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1142 * device link that was preventing the supplier from getting a
1143 * sync_state() call.
1144 */
1145 if (defer_sync_state_count)
1146 __device_links_supplier_defer_sync(supplier);
1147 else
1148 __device_links_queue_sync_state(supplier, &sync_list);
1149 }
1150
1151 dev->links.status = DL_DEV_DRIVER_BOUND;
1152
1153 device_links_write_unlock();
1154
1155 device_links_flush_sync_list(&sync_list, dev);
1156}
1157
1158/**
1159 * __device_links_no_driver - Update links of a device without a driver.
1160 * @dev: Device without a drvier.
1161 *
1162 * Delete all non-persistent links from this device to any suppliers.
1163 *
1164 * Persistent links stay around, but their status is changed to "available",
1165 * unless they already are in the "supplier unbind in progress" state in which
1166 * case they need not be updated.
1167 *
1168 * Links without the DL_FLAG_MANAGED flag set are ignored.
1169 */
1170static void __device_links_no_driver(struct device *dev)
1171{
1172 struct device_link *link, *ln;
1173
1174 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1175 if (!(link->flags & DL_FLAG_MANAGED))
1176 continue;
1177
1178 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1179 device_link_drop_managed(link);
1180 continue;
1181 }
1182
1183 if (link->status != DL_STATE_CONSUMER_PROBE &&
1184 link->status != DL_STATE_ACTIVE)
1185 continue;
1186
1187 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1188 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1189 } else {
1190 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1191 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1192 }
1193 }
1194
1195 dev->links.status = DL_DEV_NO_DRIVER;
1196}
1197
1198/**
1199 * device_links_no_driver - Update links after failing driver probe.
1200 * @dev: Device whose driver has just failed to probe.
1201 *
1202 * Clean up leftover links to consumers for @dev and invoke
1203 * %__device_links_no_driver() to update links to suppliers for it as
1204 * appropriate.
1205 *
1206 * Links without the DL_FLAG_MANAGED flag set are ignored.
1207 */
1208void device_links_no_driver(struct device *dev)
1209{
1210 struct device_link *link;
1211
1212 device_links_write_lock();
1213
1214 list_for_each_entry(link, &dev->links.consumers, s_node) {
1215 if (!(link->flags & DL_FLAG_MANAGED))
1216 continue;
1217
1218 /*
1219 * The probe has failed, so if the status of the link is
1220 * "consumer probe" or "active", it must have been added by
1221 * a probing consumer while this device was still probing.
1222 * Change its state to "dormant", as it represents a valid
1223 * relationship, but it is not functionally meaningful.
1224 */
1225 if (link->status == DL_STATE_CONSUMER_PROBE ||
1226 link->status == DL_STATE_ACTIVE)
1227 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1228 }
1229
1230 __device_links_no_driver(dev);
1231
1232 device_links_write_unlock();
1233}
1234
1235/**
1236 * device_links_driver_cleanup - Update links after driver removal.
1237 * @dev: Device whose driver has just gone away.
1238 *
1239 * Update links to consumers for @dev by changing their status to "dormant" and
1240 * invoke %__device_links_no_driver() to update links to suppliers for it as
1241 * appropriate.
1242 *
1243 * Links without the DL_FLAG_MANAGED flag set are ignored.
1244 */
1245void device_links_driver_cleanup(struct device *dev)
1246{
1247 struct device_link *link, *ln;
1248
1249 device_links_write_lock();
1250
1251 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1252 if (!(link->flags & DL_FLAG_MANAGED))
1253 continue;
1254
1255 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1256 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1257
1258 /*
1259 * autoremove the links between this @dev and its consumer
1260 * devices that are not active, i.e. where the link state
1261 * has moved to DL_STATE_SUPPLIER_UNBIND.
1262 */
1263 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1264 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1265 device_link_drop_managed(link);
1266
1267 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1268 }
1269
1270 list_del_init(&dev->links.defer_hook);
1271 __device_links_no_driver(dev);
1272
1273 device_links_write_unlock();
1274}
1275
1276/**
1277 * device_links_busy - Check if there are any busy links to consumers.
1278 * @dev: Device to check.
1279 *
1280 * Check each consumer of the device and return 'true' if its link's status
1281 * is one of "consumer probe" or "active" (meaning that the given consumer is
1282 * probing right now or its driver is present). Otherwise, change the link
1283 * state to "supplier unbind" to prevent the consumer from being probed
1284 * successfully going forward.
1285 *
1286 * Return 'false' if there are no probing or active consumers.
1287 *
1288 * Links without the DL_FLAG_MANAGED flag set are ignored.
1289 */
1290bool device_links_busy(struct device *dev)
1291{
1292 struct device_link *link;
1293 bool ret = false;
1294
1295 device_links_write_lock();
1296
1297 list_for_each_entry(link, &dev->links.consumers, s_node) {
1298 if (!(link->flags & DL_FLAG_MANAGED))
1299 continue;
1300
1301 if (link->status == DL_STATE_CONSUMER_PROBE
1302 || link->status == DL_STATE_ACTIVE) {
1303 ret = true;
1304 break;
1305 }
1306 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1307 }
1308
1309 dev->links.status = DL_DEV_UNBINDING;
1310
1311 device_links_write_unlock();
1312 return ret;
1313}
1314
1315/**
1316 * device_links_unbind_consumers - Force unbind consumers of the given device.
1317 * @dev: Device to unbind the consumers of.
1318 *
1319 * Walk the list of links to consumers for @dev and if any of them is in the
1320 * "consumer probe" state, wait for all device probes in progress to complete
1321 * and start over.
1322 *
1323 * If that's not the case, change the status of the link to "supplier unbind"
1324 * and check if the link was in the "active" state. If so, force the consumer
1325 * driver to unbind and start over (the consumer will not re-probe as we have
1326 * changed the state of the link already).
1327 *
1328 * Links without the DL_FLAG_MANAGED flag set are ignored.
1329 */
1330void device_links_unbind_consumers(struct device *dev)
1331{
1332 struct device_link *link;
1333
1334 start:
1335 device_links_write_lock();
1336
1337 list_for_each_entry(link, &dev->links.consumers, s_node) {
1338 enum device_link_state status;
1339
1340 if (!(link->flags & DL_FLAG_MANAGED) ||
1341 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1342 continue;
1343
1344 status = link->status;
1345 if (status == DL_STATE_CONSUMER_PROBE) {
1346 device_links_write_unlock();
1347
1348 wait_for_device_probe();
1349 goto start;
1350 }
1351 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1352 if (status == DL_STATE_ACTIVE) {
1353 struct device *consumer = link->consumer;
1354
1355 get_device(consumer);
1356
1357 device_links_write_unlock();
1358
1359 device_release_driver_internal(consumer, NULL,
1360 consumer->parent);
1361 put_device(consumer);
1362 goto start;
1363 }
1364 }
1365
1366 device_links_write_unlock();
1367}
1368
1369/**
1370 * device_links_purge - Delete existing links to other devices.
1371 * @dev: Target device.
1372 */
1373static void device_links_purge(struct device *dev)
1374{
1375 struct device_link *link, *ln;
1376
1377 if (dev->class == &devlink_class)
1378 return;
1379
1380 mutex_lock(&wfs_lock);
1381 list_del(&dev->links.needs_suppliers);
1382 mutex_unlock(&wfs_lock);
1383
1384 /*
1385 * Delete all of the remaining links from this device to any other
1386 * devices (either consumers or suppliers).
1387 */
1388 device_links_write_lock();
1389
1390 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1391 WARN_ON(link->status == DL_STATE_ACTIVE);
1392 __device_link_del(&link->kref);
1393 }
1394
1395 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1396 WARN_ON(link->status != DL_STATE_DORMANT &&
1397 link->status != DL_STATE_NONE);
1398 __device_link_del(&link->kref);
1399 }
1400
1401 device_links_write_unlock();
1402}
1403
1404static u32 fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY;
1405static int __init fw_devlink_setup(char *arg)
1406{
1407 if (!arg)
1408 return -EINVAL;
1409
1410 if (strcmp(arg, "off") == 0) {
1411 fw_devlink_flags = 0;
1412 } else if (strcmp(arg, "permissive") == 0) {
1413 fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY;
1414 } else if (strcmp(arg, "on") == 0) {
1415 fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER;
1416 } else if (strcmp(arg, "rpm") == 0) {
1417 fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER |
1418 DL_FLAG_PM_RUNTIME;
1419 }
1420 return 0;
1421}
1422early_param("fw_devlink", fw_devlink_setup);
1423
1424u32 fw_devlink_get_flags(void)
1425{
1426 return fw_devlink_flags;
1427}
1428
1429static bool fw_devlink_is_permissive(void)
1430{
1431 return fw_devlink_flags == DL_FLAG_SYNC_STATE_ONLY;
1432}
1433
1434static void fw_devlink_link_device(struct device *dev)
1435{
1436 int fw_ret;
1437
1438 if (!fw_devlink_flags)
1439 return;
1440
1441 mutex_lock(&defer_fw_devlink_lock);
1442 if (!defer_fw_devlink_count)
1443 device_link_add_missing_supplier_links();
1444
1445 /*
1446 * The device's fwnode not having add_links() doesn't affect if other
1447 * consumers can find this device as a supplier. So, this check is
1448 * intentionally placed after device_link_add_missing_supplier_links().
1449 */
1450 if (!fwnode_has_op(dev->fwnode, add_links))
1451 goto out;
1452
1453 /*
1454 * If fw_devlink is being deferred, assume all devices have mandatory
1455 * suppliers they need to link to later. Then, when the fw_devlink is
1456 * resumed, all these devices will get a chance to try and link to any
1457 * suppliers they have.
1458 */
1459 if (!defer_fw_devlink_count) {
1460 fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
1461 if (fw_ret == -ENODEV && fw_devlink_is_permissive())
1462 fw_ret = -EAGAIN;
1463 } else {
1464 fw_ret = -ENODEV;
1465 /*
1466 * defer_hook is not used to add device to deferred_sync list
1467 * until device is bound. Since deferred fw devlink also blocks
1468 * probing, same list hook can be used for deferred_fw_devlink.
1469 */
1470 list_add_tail(&dev->links.defer_hook, &deferred_fw_devlink);
1471 }
1472
1473 if (fw_ret == -ENODEV)
1474 device_link_wait_for_mandatory_supplier(dev);
1475 else if (fw_ret)
1476 device_link_wait_for_optional_supplier(dev);
1477
1478out:
1479 mutex_unlock(&defer_fw_devlink_lock);
1480}
1481
1482/**
1483 * fw_devlink_pause - Pause parsing of fwnode to create device links
1484 *
1485 * Calling this function defers any fwnode parsing to create device links until
1486 * fw_devlink_resume() is called. Both these functions are ref counted and the
1487 * caller needs to match the calls.
1488 *
1489 * While fw_devlink is paused:
1490 * - Any device that is added won't have its fwnode parsed to create device
1491 * links.
1492 * - The probe of the device will also be deferred during this period.
1493 * - Any devices that were already added, but waiting for suppliers won't be
1494 * able to link to newly added devices.
1495 *
1496 * Once fw_devlink_resume():
1497 * - All the fwnodes that was not parsed will be parsed.
1498 * - All the devices that were deferred probing will be reattempted if they
1499 * aren't waiting for any more suppliers.
1500 *
1501 * This pair of functions, is mainly meant to optimize the parsing of fwnodes
1502 * when a lot of devices that need to link to each other are added in a short
1503 * interval of time. For example, adding all the top level devices in a system.
1504 *
1505 * For example, if N devices are added and:
1506 * - All the consumers are added before their suppliers
1507 * - All the suppliers of the N devices are part of the N devices
1508 *
1509 * Then:
1510 *
1511 * - With the use of fw_devlink_pause() and fw_devlink_resume(), each device
1512 * will only need one parsing of its fwnode because it is guaranteed to find
1513 * all the supplier devices already registered and ready to link to. It won't
1514 * have to do another pass later to find one or more suppliers it couldn't
1515 * find in the first parse of the fwnode. So, we'll only need O(N) fwnode
1516 * parses.
1517 *
1518 * - Without the use of fw_devlink_pause() and fw_devlink_resume(), we would
1519 * end up doing O(N^2) parses of fwnodes because every device that's added is
1520 * guaranteed to trigger a parse of the fwnode of every device added before
1521 * it. This O(N^2) parse is made worse by the fact that when a fwnode of a
1522 * device is parsed, all it descendant devices might need to have their
1523 * fwnodes parsed too (even if the devices themselves aren't added).
1524 */
1525void fw_devlink_pause(void)
1526{
1527 mutex_lock(&defer_fw_devlink_lock);
1528 defer_fw_devlink_count++;
1529 mutex_unlock(&defer_fw_devlink_lock);
1530}
1531
1532/** fw_devlink_resume - Resume parsing of fwnode to create device links
1533 *
1534 * This function is used in conjunction with fw_devlink_pause() and is ref
1535 * counted. See documentation for fw_devlink_pause() for more details.
1536 */
1537void fw_devlink_resume(void)
1538{
1539 struct device *dev, *tmp;
1540 LIST_HEAD(probe_list);
1541
1542 mutex_lock(&defer_fw_devlink_lock);
1543 if (!defer_fw_devlink_count) {
1544 WARN(true, "Unmatched fw_devlink pause/resume!");
1545 goto out;
1546 }
1547
1548 defer_fw_devlink_count--;
1549 if (defer_fw_devlink_count)
1550 goto out;
1551
1552 device_link_add_missing_supplier_links();
1553 list_splice_tail_init(&deferred_fw_devlink, &probe_list);
1554out:
1555 mutex_unlock(&defer_fw_devlink_lock);
1556
1557 /*
1558 * bus_probe_device() can cause new devices to get added and they'll
1559 * try to grab defer_fw_devlink_lock. So, this needs to be done outside
1560 * the defer_fw_devlink_lock.
1561 */
1562 list_for_each_entry_safe(dev, tmp, &probe_list, links.defer_hook) {
1563 list_del_init(&dev->links.defer_hook);
1564 bus_probe_device(dev);
1565 }
1566}
1567/* Device links support end. */
1568
1569int (*platform_notify)(struct device *dev) = NULL;
1570int (*platform_notify_remove)(struct device *dev) = NULL;
1571static struct kobject *dev_kobj;
1572struct kobject *sysfs_dev_char_kobj;
1573struct kobject *sysfs_dev_block_kobj;
1574
1575static DEFINE_MUTEX(device_hotplug_lock);
1576
1577void lock_device_hotplug(void)
1578{
1579 mutex_lock(&device_hotplug_lock);
1580}
1581
1582void unlock_device_hotplug(void)
1583{
1584 mutex_unlock(&device_hotplug_lock);
1585}
1586
1587int lock_device_hotplug_sysfs(void)
1588{
1589 if (mutex_trylock(&device_hotplug_lock))
1590 return 0;
1591
1592 /* Avoid busy looping (5 ms of sleep should do). */
1593 msleep(5);
1594 return restart_syscall();
1595}
1596
1597#ifdef CONFIG_BLOCK
1598static inline int device_is_not_partition(struct device *dev)
1599{
1600 return !(dev->type == &part_type);
1601}
1602#else
1603static inline int device_is_not_partition(struct device *dev)
1604{
1605 return 1;
1606}
1607#endif
1608
1609static int
1610device_platform_notify(struct device *dev, enum kobject_action action)
1611{
1612 int ret;
1613
1614 ret = acpi_platform_notify(dev, action);
1615 if (ret)
1616 return ret;
1617
1618 ret = software_node_notify(dev, action);
1619 if (ret)
1620 return ret;
1621
1622 if (platform_notify && action == KOBJ_ADD)
1623 platform_notify(dev);
1624 else if (platform_notify_remove && action == KOBJ_REMOVE)
1625 platform_notify_remove(dev);
1626 return 0;
1627}
1628
1629/**
1630 * dev_driver_string - Return a device's driver name, if at all possible
1631 * @dev: struct device to get the name of
1632 *
1633 * Will return the device's driver's name if it is bound to a device. If
1634 * the device is not bound to a driver, it will return the name of the bus
1635 * it is attached to. If it is not attached to a bus either, an empty
1636 * string will be returned.
1637 */
1638const char *dev_driver_string(const struct device *dev)
1639{
1640 struct device_driver *drv;
1641
1642 /* dev->driver can change to NULL underneath us because of unbinding,
1643 * so be careful about accessing it. dev->bus and dev->class should
1644 * never change once they are set, so they don't need special care.
1645 */
1646 drv = READ_ONCE(dev->driver);
1647 return drv ? drv->name :
1648 (dev->bus ? dev->bus->name :
1649 (dev->class ? dev->class->name : ""));
1650}
1651EXPORT_SYMBOL(dev_driver_string);
1652
1653#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
1654
1655static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
1656 char *buf)
1657{
1658 struct device_attribute *dev_attr = to_dev_attr(attr);
1659 struct device *dev = kobj_to_dev(kobj);
1660 ssize_t ret = -EIO;
1661
1662 if (dev_attr->show)
1663 ret = dev_attr->show(dev, dev_attr, buf);
1664 if (ret >= (ssize_t)PAGE_SIZE) {
1665 printk("dev_attr_show: %pS returned bad count\n",
1666 dev_attr->show);
1667 }
1668 return ret;
1669}
1670
1671static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
1672 const char *buf, size_t count)
1673{
1674 struct device_attribute *dev_attr = to_dev_attr(attr);
1675 struct device *dev = kobj_to_dev(kobj);
1676 ssize_t ret = -EIO;
1677
1678 if (dev_attr->store)
1679 ret = dev_attr->store(dev, dev_attr, buf, count);
1680 return ret;
1681}
1682
1683static const struct sysfs_ops dev_sysfs_ops = {
1684 .show = dev_attr_show,
1685 .store = dev_attr_store,
1686};
1687
1688#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
1689
1690ssize_t device_store_ulong(struct device *dev,
1691 struct device_attribute *attr,
1692 const char *buf, size_t size)
1693{
1694 struct dev_ext_attribute *ea = to_ext_attr(attr);
1695 int ret;
1696 unsigned long new;
1697
1698 ret = kstrtoul(buf, 0, &new);
1699 if (ret)
1700 return ret;
1701 *(unsigned long *)(ea->var) = new;
1702 /* Always return full write size even if we didn't consume all */
1703 return size;
1704}
1705EXPORT_SYMBOL_GPL(device_store_ulong);
1706
1707ssize_t device_show_ulong(struct device *dev,
1708 struct device_attribute *attr,
1709 char *buf)
1710{
1711 struct dev_ext_attribute *ea = to_ext_attr(attr);
1712 return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
1713}
1714EXPORT_SYMBOL_GPL(device_show_ulong);
1715
1716ssize_t device_store_int(struct device *dev,
1717 struct device_attribute *attr,
1718 const char *buf, size_t size)
1719{
1720 struct dev_ext_attribute *ea = to_ext_attr(attr);
1721 int ret;
1722 long new;
1723
1724 ret = kstrtol(buf, 0, &new);
1725 if (ret)
1726 return ret;
1727
1728 if (new > INT_MAX || new < INT_MIN)
1729 return -EINVAL;
1730 *(int *)(ea->var) = new;
1731 /* Always return full write size even if we didn't consume all */
1732 return size;
1733}
1734EXPORT_SYMBOL_GPL(device_store_int);
1735
1736ssize_t device_show_int(struct device *dev,
1737 struct device_attribute *attr,
1738 char *buf)
1739{
1740 struct dev_ext_attribute *ea = to_ext_attr(attr);
1741
1742 return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
1743}
1744EXPORT_SYMBOL_GPL(device_show_int);
1745
1746ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
1747 const char *buf, size_t size)
1748{
1749 struct dev_ext_attribute *ea = to_ext_attr(attr);
1750
1751 if (strtobool(buf, ea->var) < 0)
1752 return -EINVAL;
1753
1754 return size;
1755}
1756EXPORT_SYMBOL_GPL(device_store_bool);
1757
1758ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
1759 char *buf)
1760{
1761 struct dev_ext_attribute *ea = to_ext_attr(attr);
1762
1763 return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
1764}
1765EXPORT_SYMBOL_GPL(device_show_bool);
1766
1767/**
1768 * device_release - free device structure.
1769 * @kobj: device's kobject.
1770 *
1771 * This is called once the reference count for the object
1772 * reaches 0. We forward the call to the device's release
1773 * method, which should handle actually freeing the structure.
1774 */
1775static void device_release(struct kobject *kobj)
1776{
1777 struct device *dev = kobj_to_dev(kobj);
1778 struct device_private *p = dev->p;
1779
1780 /*
1781 * Some platform devices are driven without driver attached
1782 * and managed resources may have been acquired. Make sure
1783 * all resources are released.
1784 *
1785 * Drivers still can add resources into device after device
1786 * is deleted but alive, so release devres here to avoid
1787 * possible memory leak.
1788 */
1789 devres_release_all(dev);
1790
1791 if (dev->release)
1792 dev->release(dev);
1793 else if (dev->type && dev->type->release)
1794 dev->type->release(dev);
1795 else if (dev->class && dev->class->dev_release)
1796 dev->class->dev_release(dev);
1797 else
1798 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",
1799 dev_name(dev));
1800 kfree(p);
1801}
1802
1803static const void *device_namespace(struct kobject *kobj)
1804{
1805 struct device *dev = kobj_to_dev(kobj);
1806 const void *ns = NULL;
1807
1808 if (dev->class && dev->class->ns_type)
1809 ns = dev->class->namespace(dev);
1810
1811 return ns;
1812}
1813
1814static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
1815{
1816 struct device *dev = kobj_to_dev(kobj);
1817
1818 if (dev->class && dev->class->get_ownership)
1819 dev->class->get_ownership(dev, uid, gid);
1820}
1821
1822static struct kobj_type device_ktype = {
1823 .release = device_release,
1824 .sysfs_ops = &dev_sysfs_ops,
1825 .namespace = device_namespace,
1826 .get_ownership = device_get_ownership,
1827};
1828
1829
1830static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
1831{
1832 struct kobj_type *ktype = get_ktype(kobj);
1833
1834 if (ktype == &device_ktype) {
1835 struct device *dev = kobj_to_dev(kobj);
1836 if (dev->bus)
1837 return 1;
1838 if (dev->class)
1839 return 1;
1840 }
1841 return 0;
1842}
1843
1844static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
1845{
1846 struct device *dev = kobj_to_dev(kobj);
1847
1848 if (dev->bus)
1849 return dev->bus->name;
1850 if (dev->class)
1851 return dev->class->name;
1852 return NULL;
1853}
1854
1855static int dev_uevent(struct kset *kset, struct kobject *kobj,
1856 struct kobj_uevent_env *env)
1857{
1858 struct device *dev = kobj_to_dev(kobj);
1859 int retval = 0;
1860
1861 /* add device node properties if present */
1862 if (MAJOR(dev->devt)) {
1863 const char *tmp;
1864 const char *name;
1865 umode_t mode = 0;
1866 kuid_t uid = GLOBAL_ROOT_UID;
1867 kgid_t gid = GLOBAL_ROOT_GID;
1868
1869 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
1870 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
1871 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
1872 if (name) {
1873 add_uevent_var(env, "DEVNAME=%s", name);
1874 if (mode)
1875 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
1876 if (!uid_eq(uid, GLOBAL_ROOT_UID))
1877 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
1878 if (!gid_eq(gid, GLOBAL_ROOT_GID))
1879 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
1880 kfree(tmp);
1881 }
1882 }
1883
1884 if (dev->type && dev->type->name)
1885 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
1886
1887 if (dev->driver)
1888 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
1889
1890 /* Add common DT information about the device */
1891 of_device_uevent(dev, env);
1892
1893 /* have the bus specific function add its stuff */
1894 if (dev->bus && dev->bus->uevent) {
1895 retval = dev->bus->uevent(dev, env);
1896 if (retval)
1897 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
1898 dev_name(dev), __func__, retval);
1899 }
1900
1901 /* have the class specific function add its stuff */
1902 if (dev->class && dev->class->dev_uevent) {
1903 retval = dev->class->dev_uevent(dev, env);
1904 if (retval)
1905 pr_debug("device: '%s': %s: class uevent() "
1906 "returned %d\n", dev_name(dev),
1907 __func__, retval);
1908 }
1909
1910 /* have the device type specific function add its stuff */
1911 if (dev->type && dev->type->uevent) {
1912 retval = dev->type->uevent(dev, env);
1913 if (retval)
1914 pr_debug("device: '%s': %s: dev_type uevent() "
1915 "returned %d\n", dev_name(dev),
1916 __func__, retval);
1917 }
1918
1919 return retval;
1920}
1921
1922static const struct kset_uevent_ops device_uevent_ops = {
1923 .filter = dev_uevent_filter,
1924 .name = dev_uevent_name,
1925 .uevent = dev_uevent,
1926};
1927
1928static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
1929 char *buf)
1930{
1931 struct kobject *top_kobj;
1932 struct kset *kset;
1933 struct kobj_uevent_env *env = NULL;
1934 int i;
1935 size_t count = 0;
1936 int retval;
1937
1938 /* search the kset, the device belongs to */
1939 top_kobj = &dev->kobj;
1940 while (!top_kobj->kset && top_kobj->parent)
1941 top_kobj = top_kobj->parent;
1942 if (!top_kobj->kset)
1943 goto out;
1944
1945 kset = top_kobj->kset;
1946 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
1947 goto out;
1948
1949 /* respect filter */
1950 if (kset->uevent_ops && kset->uevent_ops->filter)
1951 if (!kset->uevent_ops->filter(kset, &dev->kobj))
1952 goto out;
1953
1954 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
1955 if (!env)
1956 return -ENOMEM;
1957
1958 /* let the kset specific function add its keys */
1959 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
1960 if (retval)
1961 goto out;
1962
1963 /* copy keys to file */
1964 for (i = 0; i < env->envp_idx; i++)
1965 count += sprintf(&buf[count], "%s\n", env->envp[i]);
1966out:
1967 kfree(env);
1968 return count;
1969}
1970
1971static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
1972 const char *buf, size_t count)
1973{
1974 int rc;
1975
1976 rc = kobject_synth_uevent(&dev->kobj, buf, count);
1977
1978 if (rc) {
1979 dev_err(dev, "uevent: failed to send synthetic uevent\n");
1980 return rc;
1981 }
1982
1983 return count;
1984}
1985static DEVICE_ATTR_RW(uevent);
1986
1987static ssize_t online_show(struct device *dev, struct device_attribute *attr,
1988 char *buf)
1989{
1990 bool val;
1991
1992 device_lock(dev);
1993 val = !dev->offline;
1994 device_unlock(dev);
1995 return sprintf(buf, "%u\n", val);
1996}
1997
1998static ssize_t online_store(struct device *dev, struct device_attribute *attr,
1999 const char *buf, size_t count)
2000{
2001 bool val;
2002 int ret;
2003
2004 ret = strtobool(buf, &val);
2005 if (ret < 0)
2006 return ret;
2007
2008 ret = lock_device_hotplug_sysfs();
2009 if (ret)
2010 return ret;
2011
2012 ret = val ? device_online(dev) : device_offline(dev);
2013 unlock_device_hotplug();
2014 return ret < 0 ? ret : count;
2015}
2016static DEVICE_ATTR_RW(online);
2017
2018int device_add_groups(struct device *dev, const struct attribute_group **groups)
2019{
2020 return sysfs_create_groups(&dev->kobj, groups);
2021}
2022EXPORT_SYMBOL_GPL(device_add_groups);
2023
2024void device_remove_groups(struct device *dev,
2025 const struct attribute_group **groups)
2026{
2027 sysfs_remove_groups(&dev->kobj, groups);
2028}
2029EXPORT_SYMBOL_GPL(device_remove_groups);
2030
2031union device_attr_group_devres {
2032 const struct attribute_group *group;
2033 const struct attribute_group **groups;
2034};
2035
2036static int devm_attr_group_match(struct device *dev, void *res, void *data)
2037{
2038 return ((union device_attr_group_devres *)res)->group == data;
2039}
2040
2041static void devm_attr_group_remove(struct device *dev, void *res)
2042{
2043 union device_attr_group_devres *devres = res;
2044 const struct attribute_group *group = devres->group;
2045
2046 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2047 sysfs_remove_group(&dev->kobj, group);
2048}
2049
2050static void devm_attr_groups_remove(struct device *dev, void *res)
2051{
2052 union device_attr_group_devres *devres = res;
2053 const struct attribute_group **groups = devres->groups;
2054
2055 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2056 sysfs_remove_groups(&dev->kobj, groups);
2057}
2058
2059/**
2060 * devm_device_add_group - given a device, create a managed attribute group
2061 * @dev: The device to create the group for
2062 * @grp: The attribute group to create
2063 *
2064 * This function creates a group for the first time. It will explicitly
2065 * warn and error if any of the attribute files being created already exist.
2066 *
2067 * Returns 0 on success or error code on failure.
2068 */
2069int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2070{
2071 union device_attr_group_devres *devres;
2072 int error;
2073
2074 devres = devres_alloc(devm_attr_group_remove,
2075 sizeof(*devres), GFP_KERNEL);
2076 if (!devres)
2077 return -ENOMEM;
2078
2079 error = sysfs_create_group(&dev->kobj, grp);
2080 if (error) {
2081 devres_free(devres);
2082 return error;
2083 }
2084
2085 devres->group = grp;
2086 devres_add(dev, devres);
2087 return 0;
2088}
2089EXPORT_SYMBOL_GPL(devm_device_add_group);
2090
2091/**
2092 * devm_device_remove_group: remove a managed group from a device
2093 * @dev: device to remove the group from
2094 * @grp: group to remove
2095 *
2096 * This function removes a group of attributes from a device. The attributes
2097 * previously have to have been created for this group, otherwise it will fail.
2098 */
2099void devm_device_remove_group(struct device *dev,
2100 const struct attribute_group *grp)
2101{
2102 WARN_ON(devres_release(dev, devm_attr_group_remove,
2103 devm_attr_group_match,
2104 /* cast away const */ (void *)grp));
2105}
2106EXPORT_SYMBOL_GPL(devm_device_remove_group);
2107
2108/**
2109 * devm_device_add_groups - create a bunch of managed attribute groups
2110 * @dev: The device to create the group for
2111 * @groups: The attribute groups to create, NULL terminated
2112 *
2113 * This function creates a bunch of managed attribute groups. If an error
2114 * occurs when creating a group, all previously created groups will be
2115 * removed, unwinding everything back to the original state when this
2116 * function was called. It will explicitly warn and error if any of the
2117 * attribute files being created already exist.
2118 *
2119 * Returns 0 on success or error code from sysfs_create_group on failure.
2120 */
2121int devm_device_add_groups(struct device *dev,
2122 const struct attribute_group **groups)
2123{
2124 union device_attr_group_devres *devres;
2125 int error;
2126
2127 devres = devres_alloc(devm_attr_groups_remove,
2128 sizeof(*devres), GFP_KERNEL);
2129 if (!devres)
2130 return -ENOMEM;
2131
2132 error = sysfs_create_groups(&dev->kobj, groups);
2133 if (error) {
2134 devres_free(devres);
2135 return error;
2136 }
2137
2138 devres->groups = groups;
2139 devres_add(dev, devres);
2140 return 0;
2141}
2142EXPORT_SYMBOL_GPL(devm_device_add_groups);
2143
2144/**
2145 * devm_device_remove_groups - remove a list of managed groups
2146 *
2147 * @dev: The device for the groups to be removed from
2148 * @groups: NULL terminated list of groups to be removed
2149 *
2150 * If groups is not NULL, remove the specified groups from the device.
2151 */
2152void devm_device_remove_groups(struct device *dev,
2153 const struct attribute_group **groups)
2154{
2155 WARN_ON(devres_release(dev, devm_attr_groups_remove,
2156 devm_attr_group_match,
2157 /* cast away const */ (void *)groups));
2158}
2159EXPORT_SYMBOL_GPL(devm_device_remove_groups);
2160
2161static int device_add_attrs(struct device *dev)
2162{
2163 struct class *class = dev->class;
2164 const struct device_type *type = dev->type;
2165 int error;
2166
2167 if (class) {
2168 error = device_add_groups(dev, class->dev_groups);
2169 if (error)
2170 return error;
2171 }
2172
2173 if (type) {
2174 error = device_add_groups(dev, type->groups);
2175 if (error)
2176 goto err_remove_class_groups;
2177 }
2178
2179 error = device_add_groups(dev, dev->groups);
2180 if (error)
2181 goto err_remove_type_groups;
2182
2183 if (device_supports_offline(dev) && !dev->offline_disabled) {
2184 error = device_create_file(dev, &dev_attr_online);
2185 if (error)
2186 goto err_remove_dev_groups;
2187 }
2188
2189 if (fw_devlink_flags && !fw_devlink_is_permissive()) {
2190 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2191 if (error)
2192 goto err_remove_dev_online;
2193 }
2194
2195 return 0;
2196
2197 err_remove_dev_online:
2198 device_remove_file(dev, &dev_attr_online);
2199 err_remove_dev_groups:
2200 device_remove_groups(dev, dev->groups);
2201 err_remove_type_groups:
2202 if (type)
2203 device_remove_groups(dev, type->groups);
2204 err_remove_class_groups:
2205 if (class)
2206 device_remove_groups(dev, class->dev_groups);
2207
2208 return error;
2209}
2210
2211static void device_remove_attrs(struct device *dev)
2212{
2213 struct class *class = dev->class;
2214 const struct device_type *type = dev->type;
2215
2216 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2217 device_remove_file(dev, &dev_attr_online);
2218 device_remove_groups(dev, dev->groups);
2219
2220 if (type)
2221 device_remove_groups(dev, type->groups);
2222
2223 if (class)
2224 device_remove_groups(dev, class->dev_groups);
2225}
2226
2227static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2228 char *buf)
2229{
2230 return print_dev_t(buf, dev->devt);
2231}
2232static DEVICE_ATTR_RO(dev);
2233
2234/* /sys/devices/ */
2235struct kset *devices_kset;
2236
2237/**
2238 * devices_kset_move_before - Move device in the devices_kset's list.
2239 * @deva: Device to move.
2240 * @devb: Device @deva should come before.
2241 */
2242static void devices_kset_move_before(struct device *deva, struct device *devb)
2243{
2244 if (!devices_kset)
2245 return;
2246 pr_debug("devices_kset: Moving %s before %s\n",
2247 dev_name(deva), dev_name(devb));
2248 spin_lock(&devices_kset->list_lock);
2249 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2250 spin_unlock(&devices_kset->list_lock);
2251}
2252
2253/**
2254 * devices_kset_move_after - Move device in the devices_kset's list.
2255 * @deva: Device to move
2256 * @devb: Device @deva should come after.
2257 */
2258static void devices_kset_move_after(struct device *deva, struct device *devb)
2259{
2260 if (!devices_kset)
2261 return;
2262 pr_debug("devices_kset: Moving %s after %s\n",
2263 dev_name(deva), dev_name(devb));
2264 spin_lock(&devices_kset->list_lock);
2265 list_move(&deva->kobj.entry, &devb->kobj.entry);
2266 spin_unlock(&devices_kset->list_lock);
2267}
2268
2269/**
2270 * devices_kset_move_last - move the device to the end of devices_kset's list.
2271 * @dev: device to move
2272 */
2273void devices_kset_move_last(struct device *dev)
2274{
2275 if (!devices_kset)
2276 return;
2277 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2278 spin_lock(&devices_kset->list_lock);
2279 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2280 spin_unlock(&devices_kset->list_lock);
2281}
2282
2283/**
2284 * device_create_file - create sysfs attribute file for device.
2285 * @dev: device.
2286 * @attr: device attribute descriptor.
2287 */
2288int device_create_file(struct device *dev,
2289 const struct device_attribute *attr)
2290{
2291 int error = 0;
2292
2293 if (dev) {
2294 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2295 "Attribute %s: write permission without 'store'\n",
2296 attr->attr.name);
2297 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2298 "Attribute %s: read permission without 'show'\n",
2299 attr->attr.name);
2300 error = sysfs_create_file(&dev->kobj, &attr->attr);
2301 }
2302
2303 return error;
2304}
2305EXPORT_SYMBOL_GPL(device_create_file);
2306
2307/**
2308 * device_remove_file - remove sysfs attribute file.
2309 * @dev: device.
2310 * @attr: device attribute descriptor.
2311 */
2312void device_remove_file(struct device *dev,
2313 const struct device_attribute *attr)
2314{
2315 if (dev)
2316 sysfs_remove_file(&dev->kobj, &attr->attr);
2317}
2318EXPORT_SYMBOL_GPL(device_remove_file);
2319
2320/**
2321 * device_remove_file_self - remove sysfs attribute file from its own method.
2322 * @dev: device.
2323 * @attr: device attribute descriptor.
2324 *
2325 * See kernfs_remove_self() for details.
2326 */
2327bool device_remove_file_self(struct device *dev,
2328 const struct device_attribute *attr)
2329{
2330 if (dev)
2331 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2332 else
2333 return false;
2334}
2335EXPORT_SYMBOL_GPL(device_remove_file_self);
2336
2337/**
2338 * device_create_bin_file - create sysfs binary attribute file for device.
2339 * @dev: device.
2340 * @attr: device binary attribute descriptor.
2341 */
2342int device_create_bin_file(struct device *dev,
2343 const struct bin_attribute *attr)
2344{
2345 int error = -EINVAL;
2346 if (dev)
2347 error = sysfs_create_bin_file(&dev->kobj, attr);
2348 return error;
2349}
2350EXPORT_SYMBOL_GPL(device_create_bin_file);
2351
2352/**
2353 * device_remove_bin_file - remove sysfs binary attribute file
2354 * @dev: device.
2355 * @attr: device binary attribute descriptor.
2356 */
2357void device_remove_bin_file(struct device *dev,
2358 const struct bin_attribute *attr)
2359{
2360 if (dev)
2361 sysfs_remove_bin_file(&dev->kobj, attr);
2362}
2363EXPORT_SYMBOL_GPL(device_remove_bin_file);
2364
2365static void klist_children_get(struct klist_node *n)
2366{
2367 struct device_private *p = to_device_private_parent(n);
2368 struct device *dev = p->device;
2369
2370 get_device(dev);
2371}
2372
2373static void klist_children_put(struct klist_node *n)
2374{
2375 struct device_private *p = to_device_private_parent(n);
2376 struct device *dev = p->device;
2377
2378 put_device(dev);
2379}
2380
2381/**
2382 * device_initialize - init device structure.
2383 * @dev: device.
2384 *
2385 * This prepares the device for use by other layers by initializing
2386 * its fields.
2387 * It is the first half of device_register(), if called by
2388 * that function, though it can also be called separately, so one
2389 * may use @dev's fields. In particular, get_device()/put_device()
2390 * may be used for reference counting of @dev after calling this
2391 * function.
2392 *
2393 * All fields in @dev must be initialized by the caller to 0, except
2394 * for those explicitly set to some other value. The simplest
2395 * approach is to use kzalloc() to allocate the structure containing
2396 * @dev.
2397 *
2398 * NOTE: Use put_device() to give up your reference instead of freeing
2399 * @dev directly once you have called this function.
2400 */
2401void device_initialize(struct device *dev)
2402{
2403 dev->kobj.kset = devices_kset;
2404 kobject_init(&dev->kobj, &device_ktype);
2405 INIT_LIST_HEAD(&dev->dma_pools);
2406 mutex_init(&dev->mutex);
2407#ifdef CONFIG_PROVE_LOCKING
2408 mutex_init(&dev->lockdep_mutex);
2409#endif
2410 lockdep_set_novalidate_class(&dev->mutex);
2411 spin_lock_init(&dev->devres_lock);
2412 INIT_LIST_HEAD(&dev->devres_head);
2413 device_pm_init(dev);
2414 set_dev_node(dev, -1);
2415#ifdef CONFIG_GENERIC_MSI_IRQ
2416 INIT_LIST_HEAD(&dev->msi_list);
2417#endif
2418 INIT_LIST_HEAD(&dev->links.consumers);
2419 INIT_LIST_HEAD(&dev->links.suppliers);
2420 INIT_LIST_HEAD(&dev->links.needs_suppliers);
2421 INIT_LIST_HEAD(&dev->links.defer_hook);
2422 dev->links.status = DL_DEV_NO_DRIVER;
2423}
2424EXPORT_SYMBOL_GPL(device_initialize);
2425
2426struct kobject *virtual_device_parent(struct device *dev)
2427{
2428 static struct kobject *virtual_dir = NULL;
2429
2430 if (!virtual_dir)
2431 virtual_dir = kobject_create_and_add("virtual",
2432 &devices_kset->kobj);
2433
2434 return virtual_dir;
2435}
2436
2437struct class_dir {
2438 struct kobject kobj;
2439 struct class *class;
2440};
2441
2442#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2443
2444static void class_dir_release(struct kobject *kobj)
2445{
2446 struct class_dir *dir = to_class_dir(kobj);
2447 kfree(dir);
2448}
2449
2450static const
2451struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
2452{
2453 struct class_dir *dir = to_class_dir(kobj);
2454 return dir->class->ns_type;
2455}
2456
2457static struct kobj_type class_dir_ktype = {
2458 .release = class_dir_release,
2459 .sysfs_ops = &kobj_sysfs_ops,
2460 .child_ns_type = class_dir_child_ns_type
2461};
2462
2463static struct kobject *
2464class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
2465{
2466 struct class_dir *dir;
2467 int retval;
2468
2469 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
2470 if (!dir)
2471 return ERR_PTR(-ENOMEM);
2472
2473 dir->class = class;
2474 kobject_init(&dir->kobj, &class_dir_ktype);
2475
2476 dir->kobj.kset = &class->p->glue_dirs;
2477
2478 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
2479 if (retval < 0) {
2480 kobject_put(&dir->kobj);
2481 return ERR_PTR(retval);
2482 }
2483 return &dir->kobj;
2484}
2485
2486static DEFINE_MUTEX(gdp_mutex);
2487
2488static struct kobject *get_device_parent(struct device *dev,
2489 struct device *parent)
2490{
2491 if (dev->class) {
2492 struct kobject *kobj = NULL;
2493 struct kobject *parent_kobj;
2494 struct kobject *k;
2495
2496#ifdef CONFIG_BLOCK
2497 /* block disks show up in /sys/block */
2498 if (sysfs_deprecated && dev->class == &block_class) {
2499 if (parent && parent->class == &block_class)
2500 return &parent->kobj;
2501 return &block_class.p->subsys.kobj;
2502 }
2503#endif
2504
2505 /*
2506 * If we have no parent, we live in "virtual".
2507 * Class-devices with a non class-device as parent, live
2508 * in a "glue" directory to prevent namespace collisions.
2509 */
2510 if (parent == NULL)
2511 parent_kobj = virtual_device_parent(dev);
2512 else if (parent->class && !dev->class->ns_type)
2513 return &parent->kobj;
2514 else
2515 parent_kobj = &parent->kobj;
2516
2517 mutex_lock(&gdp_mutex);
2518
2519 /* find our class-directory at the parent and reference it */
2520 spin_lock(&dev->class->p->glue_dirs.list_lock);
2521 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
2522 if (k->parent == parent_kobj) {
2523 kobj = kobject_get(k);
2524 break;
2525 }
2526 spin_unlock(&dev->class->p->glue_dirs.list_lock);
2527 if (kobj) {
2528 mutex_unlock(&gdp_mutex);
2529 return kobj;
2530 }
2531
2532 /* or create a new class-directory at the parent device */
2533 k = class_dir_create_and_add(dev->class, parent_kobj);
2534 /* do not emit an uevent for this simple "glue" directory */
2535 mutex_unlock(&gdp_mutex);
2536 return k;
2537 }
2538
2539 /* subsystems can specify a default root directory for their devices */
2540 if (!parent && dev->bus && dev->bus->dev_root)
2541 return &dev->bus->dev_root->kobj;
2542
2543 if (parent)
2544 return &parent->kobj;
2545 return NULL;
2546}
2547
2548static inline bool live_in_glue_dir(struct kobject *kobj,
2549 struct device *dev)
2550{
2551 if (!kobj || !dev->class ||
2552 kobj->kset != &dev->class->p->glue_dirs)
2553 return false;
2554 return true;
2555}
2556
2557static inline struct kobject *get_glue_dir(struct device *dev)
2558{
2559 return dev->kobj.parent;
2560}
2561
2562/*
2563 * make sure cleaning up dir as the last step, we need to make
2564 * sure .release handler of kobject is run with holding the
2565 * global lock
2566 */
2567static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
2568{
2569 unsigned int ref;
2570
2571 /* see if we live in a "glue" directory */
2572 if (!live_in_glue_dir(glue_dir, dev))
2573 return;
2574
2575 mutex_lock(&gdp_mutex);
2576 /**
2577 * There is a race condition between removing glue directory
2578 * and adding a new device under the glue directory.
2579 *
2580 * CPU1: CPU2:
2581 *
2582 * device_add()
2583 * get_device_parent()
2584 * class_dir_create_and_add()
2585 * kobject_add_internal()
2586 * create_dir() // create glue_dir
2587 *
2588 * device_add()
2589 * get_device_parent()
2590 * kobject_get() // get glue_dir
2591 *
2592 * device_del()
2593 * cleanup_glue_dir()
2594 * kobject_del(glue_dir)
2595 *
2596 * kobject_add()
2597 * kobject_add_internal()
2598 * create_dir() // in glue_dir
2599 * sysfs_create_dir_ns()
2600 * kernfs_create_dir_ns(sd)
2601 *
2602 * sysfs_remove_dir() // glue_dir->sd=NULL
2603 * sysfs_put() // free glue_dir->sd
2604 *
2605 * // sd is freed
2606 * kernfs_new_node(sd)
2607 * kernfs_get(glue_dir)
2608 * kernfs_add_one()
2609 * kernfs_put()
2610 *
2611 * Before CPU1 remove last child device under glue dir, if CPU2 add
2612 * a new device under glue dir, the glue_dir kobject reference count
2613 * will be increase to 2 in kobject_get(k). And CPU2 has been called
2614 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
2615 * and sysfs_put(). This result in glue_dir->sd is freed.
2616 *
2617 * Then the CPU2 will see a stale "empty" but still potentially used
2618 * glue dir around in kernfs_new_node().
2619 *
2620 * In order to avoid this happening, we also should make sure that
2621 * kernfs_node for glue_dir is released in CPU1 only when refcount
2622 * for glue_dir kobj is 1.
2623 */
2624 ref = kref_read(&glue_dir->kref);
2625 if (!kobject_has_children(glue_dir) && !--ref)
2626 kobject_del(glue_dir);
2627 kobject_put(glue_dir);
2628 mutex_unlock(&gdp_mutex);
2629}
2630
2631static int device_add_class_symlinks(struct device *dev)
2632{
2633 struct device_node *of_node = dev_of_node(dev);
2634 int error;
2635
2636 if (of_node) {
2637 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
2638 if (error)
2639 dev_warn(dev, "Error %d creating of_node link\n",error);
2640 /* An error here doesn't warrant bringing down the device */
2641 }
2642
2643 if (!dev->class)
2644 return 0;
2645
2646 error = sysfs_create_link(&dev->kobj,
2647 &dev->class->p->subsys.kobj,
2648 "subsystem");
2649 if (error)
2650 goto out_devnode;
2651
2652 if (dev->parent && device_is_not_partition(dev)) {
2653 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
2654 "device");
2655 if (error)
2656 goto out_subsys;
2657 }
2658
2659#ifdef CONFIG_BLOCK
2660 /* /sys/block has directories and does not need symlinks */
2661 if (sysfs_deprecated && dev->class == &block_class)
2662 return 0;
2663#endif
2664
2665 /* link in the class directory pointing to the device */
2666 error = sysfs_create_link(&dev->class->p->subsys.kobj,
2667 &dev->kobj, dev_name(dev));
2668 if (error)
2669 goto out_device;
2670
2671 return 0;
2672
2673out_device:
2674 sysfs_remove_link(&dev->kobj, "device");
2675
2676out_subsys:
2677 sysfs_remove_link(&dev->kobj, "subsystem");
2678out_devnode:
2679 sysfs_remove_link(&dev->kobj, "of_node");
2680 return error;
2681}
2682
2683static void device_remove_class_symlinks(struct device *dev)
2684{
2685 if (dev_of_node(dev))
2686 sysfs_remove_link(&dev->kobj, "of_node");
2687
2688 if (!dev->class)
2689 return;
2690
2691 if (dev->parent && device_is_not_partition(dev))
2692 sysfs_remove_link(&dev->kobj, "device");
2693 sysfs_remove_link(&dev->kobj, "subsystem");
2694#ifdef CONFIG_BLOCK
2695 if (sysfs_deprecated && dev->class == &block_class)
2696 return;
2697#endif
2698 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
2699}
2700
2701/**
2702 * dev_set_name - set a device name
2703 * @dev: device
2704 * @fmt: format string for the device's name
2705 */
2706int dev_set_name(struct device *dev, const char *fmt, ...)
2707{
2708 va_list vargs;
2709 int err;
2710
2711 va_start(vargs, fmt);
2712 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
2713 va_end(vargs);
2714 return err;
2715}
2716EXPORT_SYMBOL_GPL(dev_set_name);
2717
2718/**
2719 * device_to_dev_kobj - select a /sys/dev/ directory for the device
2720 * @dev: device
2721 *
2722 * By default we select char/ for new entries. Setting class->dev_obj
2723 * to NULL prevents an entry from being created. class->dev_kobj must
2724 * be set (or cleared) before any devices are registered to the class
2725 * otherwise device_create_sys_dev_entry() and
2726 * device_remove_sys_dev_entry() will disagree about the presence of
2727 * the link.
2728 */
2729static struct kobject *device_to_dev_kobj(struct device *dev)
2730{
2731 struct kobject *kobj;
2732
2733 if (dev->class)
2734 kobj = dev->class->dev_kobj;
2735 else
2736 kobj = sysfs_dev_char_kobj;
2737
2738 return kobj;
2739}
2740
2741static int device_create_sys_dev_entry(struct device *dev)
2742{
2743 struct kobject *kobj = device_to_dev_kobj(dev);
2744 int error = 0;
2745 char devt_str[15];
2746
2747 if (kobj) {
2748 format_dev_t(devt_str, dev->devt);
2749 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
2750 }
2751
2752 return error;
2753}
2754
2755static void device_remove_sys_dev_entry(struct device *dev)
2756{
2757 struct kobject *kobj = device_to_dev_kobj(dev);
2758 char devt_str[15];
2759
2760 if (kobj) {
2761 format_dev_t(devt_str, dev->devt);
2762 sysfs_remove_link(kobj, devt_str);
2763 }
2764}
2765
2766static int device_private_init(struct device *dev)
2767{
2768 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
2769 if (!dev->p)
2770 return -ENOMEM;
2771 dev->p->device = dev;
2772 klist_init(&dev->p->klist_children, klist_children_get,
2773 klist_children_put);
2774 INIT_LIST_HEAD(&dev->p->deferred_probe);
2775 return 0;
2776}
2777
2778/**
2779 * device_add - add device to device hierarchy.
2780 * @dev: device.
2781 *
2782 * This is part 2 of device_register(), though may be called
2783 * separately _iff_ device_initialize() has been called separately.
2784 *
2785 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
2786 * to the global and sibling lists for the device, then
2787 * adds it to the other relevant subsystems of the driver model.
2788 *
2789 * Do not call this routine or device_register() more than once for
2790 * any device structure. The driver model core is not designed to work
2791 * with devices that get unregistered and then spring back to life.
2792 * (Among other things, it's very hard to guarantee that all references
2793 * to the previous incarnation of @dev have been dropped.) Allocate
2794 * and register a fresh new struct device instead.
2795 *
2796 * NOTE: _Never_ directly free @dev after calling this function, even
2797 * if it returned an error! Always use put_device() to give up your
2798 * reference instead.
2799 *
2800 * Rule of thumb is: if device_add() succeeds, you should call
2801 * device_del() when you want to get rid of it. If device_add() has
2802 * *not* succeeded, use *only* put_device() to drop the reference
2803 * count.
2804 */
2805int device_add(struct device *dev)
2806{
2807 struct device *parent;
2808 struct kobject *kobj;
2809 struct class_interface *class_intf;
2810 int error = -EINVAL;
2811 struct kobject *glue_dir = NULL;
2812
2813 dev = get_device(dev);
2814 if (!dev)
2815 goto done;
2816
2817 if (!dev->p) {
2818 error = device_private_init(dev);
2819 if (error)
2820 goto done;
2821 }
2822
2823 /*
2824 * for statically allocated devices, which should all be converted
2825 * some day, we need to initialize the name. We prevent reading back
2826 * the name, and force the use of dev_name()
2827 */
2828 if (dev->init_name) {
2829 dev_set_name(dev, "%s", dev->init_name);
2830 dev->init_name = NULL;
2831 }
2832
2833 /* subsystems can specify simple device enumeration */
2834 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
2835 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
2836
2837 if (!dev_name(dev)) {
2838 error = -EINVAL;
2839 goto name_error;
2840 }
2841
2842 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
2843
2844 parent = get_device(dev->parent);
2845 kobj = get_device_parent(dev, parent);
2846 if (IS_ERR(kobj)) {
2847 error = PTR_ERR(kobj);
2848 goto parent_error;
2849 }
2850 if (kobj)
2851 dev->kobj.parent = kobj;
2852
2853 /* use parent numa_node */
2854 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
2855 set_dev_node(dev, dev_to_node(parent));
2856
2857 /* first, register with generic layer. */
2858 /* we require the name to be set before, and pass NULL */
2859 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
2860 if (error) {
2861 glue_dir = get_glue_dir(dev);
2862 goto Error;
2863 }
2864
2865 /* notify platform of device entry */
2866 error = device_platform_notify(dev, KOBJ_ADD);
2867 if (error)
2868 goto platform_error;
2869
2870 error = device_create_file(dev, &dev_attr_uevent);
2871 if (error)
2872 goto attrError;
2873
2874 error = device_add_class_symlinks(dev);
2875 if (error)
2876 goto SymlinkError;
2877 error = device_add_attrs(dev);
2878 if (error)
2879 goto AttrsError;
2880 error = bus_add_device(dev);
2881 if (error)
2882 goto BusError;
2883 error = dpm_sysfs_add(dev);
2884 if (error)
2885 goto DPMError;
2886 device_pm_add(dev);
2887
2888 if (MAJOR(dev->devt)) {
2889 error = device_create_file(dev, &dev_attr_dev);
2890 if (error)
2891 goto DevAttrError;
2892
2893 error = device_create_sys_dev_entry(dev);
2894 if (error)
2895 goto SysEntryError;
2896
2897 devtmpfs_create_node(dev);
2898 }
2899
2900 /* Notify clients of device addition. This call must come
2901 * after dpm_sysfs_add() and before kobject_uevent().
2902 */
2903 if (dev->bus)
2904 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
2905 BUS_NOTIFY_ADD_DEVICE, dev);
2906
2907 kobject_uevent(&dev->kobj, KOBJ_ADD);
2908
2909 /*
2910 * Check if any of the other devices (consumers) have been waiting for
2911 * this device (supplier) to be added so that they can create a device
2912 * link to it.
2913 *
2914 * This needs to happen after device_pm_add() because device_link_add()
2915 * requires the supplier be registered before it's called.
2916 *
2917 * But this also needs to happen before bus_probe_device() to make sure
2918 * waiting consumers can link to it before the driver is bound to the
2919 * device and the driver sync_state callback is called for this device.
2920 */
2921 if (dev->fwnode && !dev->fwnode->dev) {
2922 dev->fwnode->dev = dev;
2923 fw_devlink_link_device(dev);
2924 }
2925
2926 bus_probe_device(dev);
2927 if (parent)
2928 klist_add_tail(&dev->p->knode_parent,
2929 &parent->p->klist_children);
2930
2931 if (dev->class) {
2932 mutex_lock(&dev->class->p->mutex);
2933 /* tie the class to the device */
2934 klist_add_tail(&dev->p->knode_class,
2935 &dev->class->p->klist_devices);
2936
2937 /* notify any interfaces that the device is here */
2938 list_for_each_entry(class_intf,
2939 &dev->class->p->interfaces, node)
2940 if (class_intf->add_dev)
2941 class_intf->add_dev(dev, class_intf);
2942 mutex_unlock(&dev->class->p->mutex);
2943 }
2944done:
2945 put_device(dev);
2946 return error;
2947 SysEntryError:
2948 if (MAJOR(dev->devt))
2949 device_remove_file(dev, &dev_attr_dev);
2950 DevAttrError:
2951 device_pm_remove(dev);
2952 dpm_sysfs_remove(dev);
2953 DPMError:
2954 bus_remove_device(dev);
2955 BusError:
2956 device_remove_attrs(dev);
2957 AttrsError:
2958 device_remove_class_symlinks(dev);
2959 SymlinkError:
2960 device_remove_file(dev, &dev_attr_uevent);
2961 attrError:
2962 device_platform_notify(dev, KOBJ_REMOVE);
2963platform_error:
2964 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
2965 glue_dir = get_glue_dir(dev);
2966 kobject_del(&dev->kobj);
2967 Error:
2968 cleanup_glue_dir(dev, glue_dir);
2969parent_error:
2970 put_device(parent);
2971name_error:
2972 kfree(dev->p);
2973 dev->p = NULL;
2974 goto done;
2975}
2976EXPORT_SYMBOL_GPL(device_add);
2977
2978/**
2979 * device_register - register a device with the system.
2980 * @dev: pointer to the device structure
2981 *
2982 * This happens in two clean steps - initialize the device
2983 * and add it to the system. The two steps can be called
2984 * separately, but this is the easiest and most common.
2985 * I.e. you should only call the two helpers separately if
2986 * have a clearly defined need to use and refcount the device
2987 * before it is added to the hierarchy.
2988 *
2989 * For more information, see the kerneldoc for device_initialize()
2990 * and device_add().
2991 *
2992 * NOTE: _Never_ directly free @dev after calling this function, even
2993 * if it returned an error! Always use put_device() to give up the
2994 * reference initialized in this function instead.
2995 */
2996int device_register(struct device *dev)
2997{
2998 device_initialize(dev);
2999 return device_add(dev);
3000}
3001EXPORT_SYMBOL_GPL(device_register);
3002
3003/**
3004 * get_device - increment reference count for device.
3005 * @dev: device.
3006 *
3007 * This simply forwards the call to kobject_get(), though
3008 * we do take care to provide for the case that we get a NULL
3009 * pointer passed in.
3010 */
3011struct device *get_device(struct device *dev)
3012{
3013 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3014}
3015EXPORT_SYMBOL_GPL(get_device);
3016
3017/**
3018 * put_device - decrement reference count.
3019 * @dev: device in question.
3020 */
3021void put_device(struct device *dev)
3022{
3023 /* might_sleep(); */
3024 if (dev)
3025 kobject_put(&dev->kobj);
3026}
3027EXPORT_SYMBOL_GPL(put_device);
3028
3029bool kill_device(struct device *dev)
3030{
3031 /*
3032 * Require the device lock and set the "dead" flag to guarantee that
3033 * the update behavior is consistent with the other bitfields near
3034 * it and that we cannot have an asynchronous probe routine trying
3035 * to run while we are tearing out the bus/class/sysfs from
3036 * underneath the device.
3037 */
3038 lockdep_assert_held(&dev->mutex);
3039
3040 if (dev->p->dead)
3041 return false;
3042 dev->p->dead = true;
3043 return true;
3044}
3045EXPORT_SYMBOL_GPL(kill_device);
3046
3047/**
3048 * device_del - delete device from system.
3049 * @dev: device.
3050 *
3051 * This is the first part of the device unregistration
3052 * sequence. This removes the device from the lists we control
3053 * from here, has it removed from the other driver model
3054 * subsystems it was added to in device_add(), and removes it
3055 * from the kobject hierarchy.
3056 *
3057 * NOTE: this should be called manually _iff_ device_add() was
3058 * also called manually.
3059 */
3060void device_del(struct device *dev)
3061{
3062 struct device *parent = dev->parent;
3063 struct kobject *glue_dir = NULL;
3064 struct class_interface *class_intf;
3065
3066 device_lock(dev);
3067 kill_device(dev);
3068 device_unlock(dev);
3069
3070 if (dev->fwnode && dev->fwnode->dev == dev)
3071 dev->fwnode->dev = NULL;
3072
3073 /* Notify clients of device removal. This call must come
3074 * before dpm_sysfs_remove().
3075 */
3076 if (dev->bus)
3077 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3078 BUS_NOTIFY_DEL_DEVICE, dev);
3079
3080 dpm_sysfs_remove(dev);
3081 if (parent)
3082 klist_del(&dev->p->knode_parent);
3083 if (MAJOR(dev->devt)) {
3084 devtmpfs_delete_node(dev);
3085 device_remove_sys_dev_entry(dev);
3086 device_remove_file(dev, &dev_attr_dev);
3087 }
3088 if (dev->class) {
3089 device_remove_class_symlinks(dev);
3090
3091 mutex_lock(&dev->class->p->mutex);
3092 /* notify any interfaces that the device is now gone */
3093 list_for_each_entry(class_intf,
3094 &dev->class->p->interfaces, node)
3095 if (class_intf->remove_dev)
3096 class_intf->remove_dev(dev, class_intf);
3097 /* remove the device from the class list */
3098 klist_del(&dev->p->knode_class);
3099 mutex_unlock(&dev->class->p->mutex);
3100 }
3101 device_remove_file(dev, &dev_attr_uevent);
3102 device_remove_attrs(dev);
3103 bus_remove_device(dev);
3104 device_pm_remove(dev);
3105 driver_deferred_probe_del(dev);
3106 device_platform_notify(dev, KOBJ_REMOVE);
3107 device_remove_properties(dev);
3108 device_links_purge(dev);
3109
3110 if (dev->bus)
3111 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3112 BUS_NOTIFY_REMOVED_DEVICE, dev);
3113 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3114 glue_dir = get_glue_dir(dev);
3115 kobject_del(&dev->kobj);
3116 cleanup_glue_dir(dev, glue_dir);
3117 put_device(parent);
3118}
3119EXPORT_SYMBOL_GPL(device_del);
3120
3121/**
3122 * device_unregister - unregister device from system.
3123 * @dev: device going away.
3124 *
3125 * We do this in two parts, like we do device_register(). First,
3126 * we remove it from all the subsystems with device_del(), then
3127 * we decrement the reference count via put_device(). If that
3128 * is the final reference count, the device will be cleaned up
3129 * via device_release() above. Otherwise, the structure will
3130 * stick around until the final reference to the device is dropped.
3131 */
3132void device_unregister(struct device *dev)
3133{
3134 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3135 device_del(dev);
3136 put_device(dev);
3137}
3138EXPORT_SYMBOL_GPL(device_unregister);
3139
3140static struct device *prev_device(struct klist_iter *i)
3141{
3142 struct klist_node *n = klist_prev(i);
3143 struct device *dev = NULL;
3144 struct device_private *p;
3145
3146 if (n) {
3147 p = to_device_private_parent(n);
3148 dev = p->device;
3149 }
3150 return dev;
3151}
3152
3153static struct device *next_device(struct klist_iter *i)
3154{
3155 struct klist_node *n = klist_next(i);
3156 struct device *dev = NULL;
3157 struct device_private *p;
3158
3159 if (n) {
3160 p = to_device_private_parent(n);
3161 dev = p->device;
3162 }
3163 return dev;
3164}
3165
3166/**
3167 * device_get_devnode - path of device node file
3168 * @dev: device
3169 * @mode: returned file access mode
3170 * @uid: returned file owner
3171 * @gid: returned file group
3172 * @tmp: possibly allocated string
3173 *
3174 * Return the relative path of a possible device node.
3175 * Non-default names may need to allocate a memory to compose
3176 * a name. This memory is returned in tmp and needs to be
3177 * freed by the caller.
3178 */
3179const char *device_get_devnode(struct device *dev,
3180 umode_t *mode, kuid_t *uid, kgid_t *gid,
3181 const char **tmp)
3182{
3183 char *s;
3184
3185 *tmp = NULL;
3186
3187 /* the device type may provide a specific name */
3188 if (dev->type && dev->type->devnode)
3189 *tmp = dev->type->devnode(dev, mode, uid, gid);
3190 if (*tmp)
3191 return *tmp;
3192
3193 /* the class may provide a specific name */
3194 if (dev->class && dev->class->devnode)
3195 *tmp = dev->class->devnode(dev, mode);
3196 if (*tmp)
3197 return *tmp;
3198
3199 /* return name without allocation, tmp == NULL */
3200 if (strchr(dev_name(dev), '!') == NULL)
3201 return dev_name(dev);
3202
3203 /* replace '!' in the name with '/' */
3204 s = kstrdup(dev_name(dev), GFP_KERNEL);
3205 if (!s)
3206 return NULL;
3207 strreplace(s, '!', '/');
3208 return *tmp = s;
3209}
3210
3211/**
3212 * device_for_each_child - device child iterator.
3213 * @parent: parent struct device.
3214 * @fn: function to be called for each device.
3215 * @data: data for the callback.
3216 *
3217 * Iterate over @parent's child devices, and call @fn for each,
3218 * passing it @data.
3219 *
3220 * We check the return of @fn each time. If it returns anything
3221 * other than 0, we break out and return that value.
3222 */
3223int device_for_each_child(struct device *parent, void *data,
3224 int (*fn)(struct device *dev, void *data))
3225{
3226 struct klist_iter i;
3227 struct device *child;
3228 int error = 0;
3229
3230 if (!parent->p)
3231 return 0;
3232
3233 klist_iter_init(&parent->p->klist_children, &i);
3234 while (!error && (child = next_device(&i)))
3235 error = fn(child, data);
3236 klist_iter_exit(&i);
3237 return error;
3238}
3239EXPORT_SYMBOL_GPL(device_for_each_child);
3240
3241/**
3242 * device_for_each_child_reverse - device child iterator in reversed order.
3243 * @parent: parent struct device.
3244 * @fn: function to be called for each device.
3245 * @data: data for the callback.
3246 *
3247 * Iterate over @parent's child devices, and call @fn for each,
3248 * passing it @data.
3249 *
3250 * We check the return of @fn each time. If it returns anything
3251 * other than 0, we break out and return that value.
3252 */
3253int device_for_each_child_reverse(struct device *parent, void *data,
3254 int (*fn)(struct device *dev, void *data))
3255{
3256 struct klist_iter i;
3257 struct device *child;
3258 int error = 0;
3259
3260 if (!parent->p)
3261 return 0;
3262
3263 klist_iter_init(&parent->p->klist_children, &i);
3264 while ((child = prev_device(&i)) && !error)
3265 error = fn(child, data);
3266 klist_iter_exit(&i);
3267 return error;
3268}
3269EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3270
3271/**
3272 * device_find_child - device iterator for locating a particular device.
3273 * @parent: parent struct device
3274 * @match: Callback function to check device
3275 * @data: Data to pass to match function
3276 *
3277 * This is similar to the device_for_each_child() function above, but it
3278 * returns a reference to a device that is 'found' for later use, as
3279 * determined by the @match callback.
3280 *
3281 * The callback should return 0 if the device doesn't match and non-zero
3282 * if it does. If the callback returns non-zero and a reference to the
3283 * current device can be obtained, this function will return to the caller
3284 * and not iterate over any more devices.
3285 *
3286 * NOTE: you will need to drop the reference with put_device() after use.
3287 */
3288struct device *device_find_child(struct device *parent, void *data,
3289 int (*match)(struct device *dev, void *data))
3290{
3291 struct klist_iter i;
3292 struct device *child;
3293
3294 if (!parent)
3295 return NULL;
3296
3297 klist_iter_init(&parent->p->klist_children, &i);
3298 while ((child = next_device(&i)))
3299 if (match(child, data) && get_device(child))
3300 break;
3301 klist_iter_exit(&i);
3302 return child;
3303}
3304EXPORT_SYMBOL_GPL(device_find_child);
3305
3306/**
3307 * device_find_child_by_name - device iterator for locating a child device.
3308 * @parent: parent struct device
3309 * @name: name of the child device
3310 *
3311 * This is similar to the device_find_child() function above, but it
3312 * returns a reference to a device that has the name @name.
3313 *
3314 * NOTE: you will need to drop the reference with put_device() after use.
3315 */
3316struct device *device_find_child_by_name(struct device *parent,
3317 const char *name)
3318{
3319 struct klist_iter i;
3320 struct device *child;
3321
3322 if (!parent)
3323 return NULL;
3324
3325 klist_iter_init(&parent->p->klist_children, &i);
3326 while ((child = next_device(&i)))
3327 if (!strcmp(dev_name(child), name) && get_device(child))
3328 break;
3329 klist_iter_exit(&i);
3330 return child;
3331}
3332EXPORT_SYMBOL_GPL(device_find_child_by_name);
3333
3334int __init devices_init(void)
3335{
3336 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3337 if (!devices_kset)
3338 return -ENOMEM;
3339 dev_kobj = kobject_create_and_add("dev", NULL);
3340 if (!dev_kobj)
3341 goto dev_kobj_err;
3342 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3343 if (!sysfs_dev_block_kobj)
3344 goto block_kobj_err;
3345 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3346 if (!sysfs_dev_char_kobj)
3347 goto char_kobj_err;
3348
3349 return 0;
3350
3351 char_kobj_err:
3352 kobject_put(sysfs_dev_block_kobj);
3353 block_kobj_err:
3354 kobject_put(dev_kobj);
3355 dev_kobj_err:
3356 kset_unregister(devices_kset);
3357 return -ENOMEM;
3358}
3359
3360static int device_check_offline(struct device *dev, void *not_used)
3361{
3362 int ret;
3363
3364 ret = device_for_each_child(dev, NULL, device_check_offline);
3365 if (ret)
3366 return ret;
3367
3368 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3369}
3370
3371/**
3372 * device_offline - Prepare the device for hot-removal.
3373 * @dev: Device to be put offline.
3374 *
3375 * Execute the device bus type's .offline() callback, if present, to prepare
3376 * the device for a subsequent hot-removal. If that succeeds, the device must
3377 * not be used until either it is removed or its bus type's .online() callback
3378 * is executed.
3379 *
3380 * Call under device_hotplug_lock.
3381 */
3382int device_offline(struct device *dev)
3383{
3384 int ret;
3385
3386 if (dev->offline_disabled)
3387 return -EPERM;
3388
3389 ret = device_for_each_child(dev, NULL, device_check_offline);
3390 if (ret)
3391 return ret;
3392
3393 device_lock(dev);
3394 if (device_supports_offline(dev)) {
3395 if (dev->offline) {
3396 ret = 1;
3397 } else {
3398 ret = dev->bus->offline(dev);
3399 if (!ret) {
3400 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3401 dev->offline = true;
3402 }
3403 }
3404 }
3405 device_unlock(dev);
3406
3407 return ret;
3408}
3409
3410/**
3411 * device_online - Put the device back online after successful device_offline().
3412 * @dev: Device to be put back online.
3413 *
3414 * If device_offline() has been successfully executed for @dev, but the device
3415 * has not been removed subsequently, execute its bus type's .online() callback
3416 * to indicate that the device can be used again.
3417 *
3418 * Call under device_hotplug_lock.
3419 */
3420int device_online(struct device *dev)
3421{
3422 int ret = 0;
3423
3424 device_lock(dev);
3425 if (device_supports_offline(dev)) {
3426 if (dev->offline) {
3427 ret = dev->bus->online(dev);
3428 if (!ret) {
3429 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
3430 dev->offline = false;
3431 }
3432 } else {
3433 ret = 1;
3434 }
3435 }
3436 device_unlock(dev);
3437
3438 return ret;
3439}
3440
3441struct root_device {
3442 struct device dev;
3443 struct module *owner;
3444};
3445
3446static inline struct root_device *to_root_device(struct device *d)
3447{
3448 return container_of(d, struct root_device, dev);
3449}
3450
3451static void root_device_release(struct device *dev)
3452{
3453 kfree(to_root_device(dev));
3454}
3455
3456/**
3457 * __root_device_register - allocate and register a root device
3458 * @name: root device name
3459 * @owner: owner module of the root device, usually THIS_MODULE
3460 *
3461 * This function allocates a root device and registers it
3462 * using device_register(). In order to free the returned
3463 * device, use root_device_unregister().
3464 *
3465 * Root devices are dummy devices which allow other devices
3466 * to be grouped under /sys/devices. Use this function to
3467 * allocate a root device and then use it as the parent of
3468 * any device which should appear under /sys/devices/{name}
3469 *
3470 * The /sys/devices/{name} directory will also contain a
3471 * 'module' symlink which points to the @owner directory
3472 * in sysfs.
3473 *
3474 * Returns &struct device pointer on success, or ERR_PTR() on error.
3475 *
3476 * Note: You probably want to use root_device_register().
3477 */
3478struct device *__root_device_register(const char *name, struct module *owner)
3479{
3480 struct root_device *root;
3481 int err = -ENOMEM;
3482
3483 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
3484 if (!root)
3485 return ERR_PTR(err);
3486
3487 err = dev_set_name(&root->dev, "%s", name);
3488 if (err) {
3489 kfree(root);
3490 return ERR_PTR(err);
3491 }
3492
3493 root->dev.release = root_device_release;
3494
3495 err = device_register(&root->dev);
3496 if (err) {
3497 put_device(&root->dev);
3498 return ERR_PTR(err);
3499 }
3500
3501#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
3502 if (owner) {
3503 struct module_kobject *mk = &owner->mkobj;
3504
3505 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
3506 if (err) {
3507 device_unregister(&root->dev);
3508 return ERR_PTR(err);
3509 }
3510 root->owner = owner;
3511 }
3512#endif
3513
3514 return &root->dev;
3515}
3516EXPORT_SYMBOL_GPL(__root_device_register);
3517
3518/**
3519 * root_device_unregister - unregister and free a root device
3520 * @dev: device going away
3521 *
3522 * This function unregisters and cleans up a device that was created by
3523 * root_device_register().
3524 */
3525void root_device_unregister(struct device *dev)
3526{
3527 struct root_device *root = to_root_device(dev);
3528
3529 if (root->owner)
3530 sysfs_remove_link(&root->dev.kobj, "module");
3531
3532 device_unregister(dev);
3533}
3534EXPORT_SYMBOL_GPL(root_device_unregister);
3535
3536
3537static void device_create_release(struct device *dev)
3538{
3539 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3540 kfree(dev);
3541}
3542
3543static __printf(6, 0) struct device *
3544device_create_groups_vargs(struct class *class, struct device *parent,
3545 dev_t devt, void *drvdata,
3546 const struct attribute_group **groups,
3547 const char *fmt, va_list args)
3548{
3549 struct device *dev = NULL;
3550 int retval = -ENODEV;
3551
3552 if (class == NULL || IS_ERR(class))
3553 goto error;
3554
3555 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3556 if (!dev) {
3557 retval = -ENOMEM;
3558 goto error;
3559 }
3560
3561 device_initialize(dev);
3562 dev->devt = devt;
3563 dev->class = class;
3564 dev->parent = parent;
3565 dev->groups = groups;
3566 dev->release = device_create_release;
3567 dev_set_drvdata(dev, drvdata);
3568
3569 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
3570 if (retval)
3571 goto error;
3572
3573 retval = device_add(dev);
3574 if (retval)
3575 goto error;
3576
3577 return dev;
3578
3579error:
3580 put_device(dev);
3581 return ERR_PTR(retval);
3582}
3583
3584/**
3585 * device_create - creates a device and registers it with sysfs
3586 * @class: pointer to the struct class that this device should be registered to
3587 * @parent: pointer to the parent struct device of this new device, if any
3588 * @devt: the dev_t for the char device to be added
3589 * @drvdata: the data to be added to the device for callbacks
3590 * @fmt: string for the device's name
3591 *
3592 * This function can be used by char device classes. A struct device
3593 * will be created in sysfs, registered to the specified class.
3594 *
3595 * A "dev" file will be created, showing the dev_t for the device, if
3596 * the dev_t is not 0,0.
3597 * If a pointer to a parent struct device is passed in, the newly created
3598 * struct device will be a child of that device in sysfs.
3599 * The pointer to the struct device will be returned from the call.
3600 * Any further sysfs files that might be required can be created using this
3601 * pointer.
3602 *
3603 * Returns &struct device pointer on success, or ERR_PTR() on error.
3604 *
3605 * Note: the struct class passed to this function must have previously
3606 * been created with a call to class_create().
3607 */
3608struct device *device_create(struct class *class, struct device *parent,
3609 dev_t devt, void *drvdata, const char *fmt, ...)
3610{
3611 va_list vargs;
3612 struct device *dev;
3613
3614 va_start(vargs, fmt);
3615 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
3616 fmt, vargs);
3617 va_end(vargs);
3618 return dev;
3619}
3620EXPORT_SYMBOL_GPL(device_create);
3621
3622/**
3623 * device_create_with_groups - creates a device and registers it with sysfs
3624 * @class: pointer to the struct class that this device should be registered to
3625 * @parent: pointer to the parent struct device of this new device, if any
3626 * @devt: the dev_t for the char device to be added
3627 * @drvdata: the data to be added to the device for callbacks
3628 * @groups: NULL-terminated list of attribute groups to be created
3629 * @fmt: string for the device's name
3630 *
3631 * This function can be used by char device classes. A struct device
3632 * will be created in sysfs, registered to the specified class.
3633 * Additional attributes specified in the groups parameter will also
3634 * be created automatically.
3635 *
3636 * A "dev" file will be created, showing the dev_t for the device, if
3637 * the dev_t is not 0,0.
3638 * If a pointer to a parent struct device is passed in, the newly created
3639 * struct device will be a child of that device in sysfs.
3640 * The pointer to the struct device will be returned from the call.
3641 * Any further sysfs files that might be required can be created using this
3642 * pointer.
3643 *
3644 * Returns &struct device pointer on success, or ERR_PTR() on error.
3645 *
3646 * Note: the struct class passed to this function must have previously
3647 * been created with a call to class_create().
3648 */
3649struct device *device_create_with_groups(struct class *class,
3650 struct device *parent, dev_t devt,
3651 void *drvdata,
3652 const struct attribute_group **groups,
3653 const char *fmt, ...)
3654{
3655 va_list vargs;
3656 struct device *dev;
3657
3658 va_start(vargs, fmt);
3659 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
3660 fmt, vargs);
3661 va_end(vargs);
3662 return dev;
3663}
3664EXPORT_SYMBOL_GPL(device_create_with_groups);
3665
3666/**
3667 * device_destroy - removes a device that was created with device_create()
3668 * @class: pointer to the struct class that this device was registered with
3669 * @devt: the dev_t of the device that was previously registered
3670 *
3671 * This call unregisters and cleans up a device that was created with a
3672 * call to device_create().
3673 */
3674void device_destroy(struct class *class, dev_t devt)
3675{
3676 struct device *dev;
3677
3678 dev = class_find_device_by_devt(class, devt);
3679 if (dev) {
3680 put_device(dev);
3681 device_unregister(dev);
3682 }
3683}
3684EXPORT_SYMBOL_GPL(device_destroy);
3685
3686/**
3687 * device_rename - renames a device
3688 * @dev: the pointer to the struct device to be renamed
3689 * @new_name: the new name of the device
3690 *
3691 * It is the responsibility of the caller to provide mutual
3692 * exclusion between two different calls of device_rename
3693 * on the same device to ensure that new_name is valid and
3694 * won't conflict with other devices.
3695 *
3696 * Note: Don't call this function. Currently, the networking layer calls this
3697 * function, but that will change. The following text from Kay Sievers offers
3698 * some insight:
3699 *
3700 * Renaming devices is racy at many levels, symlinks and other stuff are not
3701 * replaced atomically, and you get a "move" uevent, but it's not easy to
3702 * connect the event to the old and new device. Device nodes are not renamed at
3703 * all, there isn't even support for that in the kernel now.
3704 *
3705 * In the meantime, during renaming, your target name might be taken by another
3706 * driver, creating conflicts. Or the old name is taken directly after you
3707 * renamed it -- then you get events for the same DEVPATH, before you even see
3708 * the "move" event. It's just a mess, and nothing new should ever rely on
3709 * kernel device renaming. Besides that, it's not even implemented now for
3710 * other things than (driver-core wise very simple) network devices.
3711 *
3712 * We are currently about to change network renaming in udev to completely
3713 * disallow renaming of devices in the same namespace as the kernel uses,
3714 * because we can't solve the problems properly, that arise with swapping names
3715 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
3716 * be allowed to some other name than eth[0-9]*, for the aforementioned
3717 * reasons.
3718 *
3719 * Make up a "real" name in the driver before you register anything, or add
3720 * some other attributes for userspace to find the device, or use udev to add
3721 * symlinks -- but never rename kernel devices later, it's a complete mess. We
3722 * don't even want to get into that and try to implement the missing pieces in
3723 * the core. We really have other pieces to fix in the driver core mess. :)
3724 */
3725int device_rename(struct device *dev, const char *new_name)
3726{
3727 struct kobject *kobj = &dev->kobj;
3728 char *old_device_name = NULL;
3729 int error;
3730
3731 dev = get_device(dev);
3732 if (!dev)
3733 return -EINVAL;
3734
3735 dev_dbg(dev, "renaming to %s\n", new_name);
3736
3737 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
3738 if (!old_device_name) {
3739 error = -ENOMEM;
3740 goto out;
3741 }
3742
3743 if (dev->class) {
3744 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
3745 kobj, old_device_name,
3746 new_name, kobject_namespace(kobj));
3747 if (error)
3748 goto out;
3749 }
3750
3751 error = kobject_rename(kobj, new_name);
3752 if (error)
3753 goto out;
3754
3755out:
3756 put_device(dev);
3757
3758 kfree(old_device_name);
3759
3760 return error;
3761}
3762EXPORT_SYMBOL_GPL(device_rename);
3763
3764static int device_move_class_links(struct device *dev,
3765 struct device *old_parent,
3766 struct device *new_parent)
3767{
3768 int error = 0;
3769
3770 if (old_parent)
3771 sysfs_remove_link(&dev->kobj, "device");
3772 if (new_parent)
3773 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
3774 "device");
3775 return error;
3776}
3777
3778/**
3779 * device_move - moves a device to a new parent
3780 * @dev: the pointer to the struct device to be moved
3781 * @new_parent: the new parent of the device (can be NULL)
3782 * @dpm_order: how to reorder the dpm_list
3783 */
3784int device_move(struct device *dev, struct device *new_parent,
3785 enum dpm_order dpm_order)
3786{
3787 int error;
3788 struct device *old_parent;
3789 struct kobject *new_parent_kobj;
3790
3791 dev = get_device(dev);
3792 if (!dev)
3793 return -EINVAL;
3794
3795 device_pm_lock();
3796 new_parent = get_device(new_parent);
3797 new_parent_kobj = get_device_parent(dev, new_parent);
3798 if (IS_ERR(new_parent_kobj)) {
3799 error = PTR_ERR(new_parent_kobj);
3800 put_device(new_parent);
3801 goto out;
3802 }
3803
3804 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
3805 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
3806 error = kobject_move(&dev->kobj, new_parent_kobj);
3807 if (error) {
3808 cleanup_glue_dir(dev, new_parent_kobj);
3809 put_device(new_parent);
3810 goto out;
3811 }
3812 old_parent = dev->parent;
3813 dev->parent = new_parent;
3814 if (old_parent)
3815 klist_remove(&dev->p->knode_parent);
3816 if (new_parent) {
3817 klist_add_tail(&dev->p->knode_parent,
3818 &new_parent->p->klist_children);
3819 set_dev_node(dev, dev_to_node(new_parent));
3820 }
3821
3822 if (dev->class) {
3823 error = device_move_class_links(dev, old_parent, new_parent);
3824 if (error) {
3825 /* We ignore errors on cleanup since we're hosed anyway... */
3826 device_move_class_links(dev, new_parent, old_parent);
3827 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
3828 if (new_parent)
3829 klist_remove(&dev->p->knode_parent);
3830 dev->parent = old_parent;
3831 if (old_parent) {
3832 klist_add_tail(&dev->p->knode_parent,
3833 &old_parent->p->klist_children);
3834 set_dev_node(dev, dev_to_node(old_parent));
3835 }
3836 }
3837 cleanup_glue_dir(dev, new_parent_kobj);
3838 put_device(new_parent);
3839 goto out;
3840 }
3841 }
3842 switch (dpm_order) {
3843 case DPM_ORDER_NONE:
3844 break;
3845 case DPM_ORDER_DEV_AFTER_PARENT:
3846 device_pm_move_after(dev, new_parent);
3847 devices_kset_move_after(dev, new_parent);
3848 break;
3849 case DPM_ORDER_PARENT_BEFORE_DEV:
3850 device_pm_move_before(new_parent, dev);
3851 devices_kset_move_before(new_parent, dev);
3852 break;
3853 case DPM_ORDER_DEV_LAST:
3854 device_pm_move_last(dev);
3855 devices_kset_move_last(dev);
3856 break;
3857 }
3858
3859 put_device(old_parent);
3860out:
3861 device_pm_unlock();
3862 put_device(dev);
3863 return error;
3864}
3865EXPORT_SYMBOL_GPL(device_move);
3866
3867static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
3868 kgid_t kgid)
3869{
3870 struct kobject *kobj = &dev->kobj;
3871 struct class *class = dev->class;
3872 const struct device_type *type = dev->type;
3873 int error;
3874
3875 if (class) {
3876 /*
3877 * Change the device groups of the device class for @dev to
3878 * @kuid/@kgid.
3879 */
3880 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
3881 kgid);
3882 if (error)
3883 return error;
3884 }
3885
3886 if (type) {
3887 /*
3888 * Change the device groups of the device type for @dev to
3889 * @kuid/@kgid.
3890 */
3891 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
3892 kgid);
3893 if (error)
3894 return error;
3895 }
3896
3897 /* Change the device groups of @dev to @kuid/@kgid. */
3898 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
3899 if (error)
3900 return error;
3901
3902 if (device_supports_offline(dev) && !dev->offline_disabled) {
3903 /* Change online device attributes of @dev to @kuid/@kgid. */
3904 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
3905 kuid, kgid);
3906 if (error)
3907 return error;
3908 }
3909
3910 return 0;
3911}
3912
3913/**
3914 * device_change_owner - change the owner of an existing device.
3915 * @dev: device.
3916 * @kuid: new owner's kuid
3917 * @kgid: new owner's kgid
3918 *
3919 * This changes the owner of @dev and its corresponding sysfs entries to
3920 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
3921 * core.
3922 *
3923 * Returns 0 on success or error code on failure.
3924 */
3925int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
3926{
3927 int error;
3928 struct kobject *kobj = &dev->kobj;
3929
3930 dev = get_device(dev);
3931 if (!dev)
3932 return -EINVAL;
3933
3934 /*
3935 * Change the kobject and the default attributes and groups of the
3936 * ktype associated with it to @kuid/@kgid.
3937 */
3938 error = sysfs_change_owner(kobj, kuid, kgid);
3939 if (error)
3940 goto out;
3941
3942 /*
3943 * Change the uevent file for @dev to the new owner. The uevent file
3944 * was created in a separate step when @dev got added and we mirror
3945 * that step here.
3946 */
3947 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
3948 kgid);
3949 if (error)
3950 goto out;
3951
3952 /*
3953 * Change the device groups, the device groups associated with the
3954 * device class, and the groups associated with the device type of @dev
3955 * to @kuid/@kgid.
3956 */
3957 error = device_attrs_change_owner(dev, kuid, kgid);
3958 if (error)
3959 goto out;
3960
3961 error = dpm_sysfs_change_owner(dev, kuid, kgid);
3962 if (error)
3963 goto out;
3964
3965#ifdef CONFIG_BLOCK
3966 if (sysfs_deprecated && dev->class == &block_class)
3967 goto out;
3968#endif
3969
3970 /*
3971 * Change the owner of the symlink located in the class directory of
3972 * the device class associated with @dev which points to the actual
3973 * directory entry for @dev to @kuid/@kgid. This ensures that the
3974 * symlink shows the same permissions as its target.
3975 */
3976 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
3977 dev_name(dev), kuid, kgid);
3978 if (error)
3979 goto out;
3980
3981out:
3982 put_device(dev);
3983 return error;
3984}
3985EXPORT_SYMBOL_GPL(device_change_owner);
3986
3987/**
3988 * device_shutdown - call ->shutdown() on each device to shutdown.
3989 */
3990void device_shutdown(void)
3991{
3992 struct device *dev, *parent;
3993
3994 wait_for_device_probe();
3995 device_block_probing();
3996
3997 cpufreq_suspend();
3998
3999 spin_lock(&devices_kset->list_lock);
4000 /*
4001 * Walk the devices list backward, shutting down each in turn.
4002 * Beware that device unplug events may also start pulling
4003 * devices offline, even as the system is shutting down.
4004 */
4005 while (!list_empty(&devices_kset->list)) {
4006 dev = list_entry(devices_kset->list.prev, struct device,
4007 kobj.entry);
4008
4009 /*
4010 * hold reference count of device's parent to
4011 * prevent it from being freed because parent's
4012 * lock is to be held
4013 */
4014 parent = get_device(dev->parent);
4015 get_device(dev);
4016 /*
4017 * Make sure the device is off the kset list, in the
4018 * event that dev->*->shutdown() doesn't remove it.
4019 */
4020 list_del_init(&dev->kobj.entry);
4021 spin_unlock(&devices_kset->list_lock);
4022
4023 /* hold lock to avoid race with probe/release */
4024 if (parent)
4025 device_lock(parent);
4026 device_lock(dev);
4027
4028 /* Don't allow any more runtime suspends */
4029 pm_runtime_get_noresume(dev);
4030 pm_runtime_barrier(dev);
4031
4032 if (dev->class && dev->class->shutdown_pre) {
4033 if (initcall_debug)
4034 dev_info(dev, "shutdown_pre\n");
4035 dev->class->shutdown_pre(dev);
4036 }
4037 if (dev->bus && dev->bus->shutdown) {
4038 if (initcall_debug)
4039 dev_info(dev, "shutdown\n");
4040 dev->bus->shutdown(dev);
4041 } else if (dev->driver && dev->driver->shutdown) {
4042 if (initcall_debug)
4043 dev_info(dev, "shutdown\n");
4044 dev->driver->shutdown(dev);
4045 }
4046
4047 device_unlock(dev);
4048 if (parent)
4049 device_unlock(parent);
4050
4051 put_device(dev);
4052 put_device(parent);
4053
4054 spin_lock(&devices_kset->list_lock);
4055 }
4056 spin_unlock(&devices_kset->list_lock);
4057}
4058
4059/*
4060 * Device logging functions
4061 */
4062
4063#ifdef CONFIG_PRINTK
4064static int
4065create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
4066{
4067 const char *subsys;
4068 size_t pos = 0;
4069
4070 if (dev->class)
4071 subsys = dev->class->name;
4072 else if (dev->bus)
4073 subsys = dev->bus->name;
4074 else
4075 return 0;
4076
4077 pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
4078 if (pos >= hdrlen)
4079 goto overflow;
4080
4081 /*
4082 * Add device identifier DEVICE=:
4083 * b12:8 block dev_t
4084 * c127:3 char dev_t
4085 * n8 netdev ifindex
4086 * +sound:card0 subsystem:devname
4087 */
4088 if (MAJOR(dev->devt)) {
4089 char c;
4090
4091 if (strcmp(subsys, "block") == 0)
4092 c = 'b';
4093 else
4094 c = 'c';
4095 pos++;
4096 pos += snprintf(hdr + pos, hdrlen - pos,
4097 "DEVICE=%c%u:%u",
4098 c, MAJOR(dev->devt), MINOR(dev->devt));
4099 } else if (strcmp(subsys, "net") == 0) {
4100 struct net_device *net = to_net_dev(dev);
4101
4102 pos++;
4103 pos += snprintf(hdr + pos, hdrlen - pos,
4104 "DEVICE=n%u", net->ifindex);
4105 } else {
4106 pos++;
4107 pos += snprintf(hdr + pos, hdrlen - pos,
4108 "DEVICE=+%s:%s", subsys, dev_name(dev));
4109 }
4110
4111 if (pos >= hdrlen)
4112 goto overflow;
4113
4114 return pos;
4115
4116overflow:
4117 dev_WARN(dev, "device/subsystem name too long");
4118 return 0;
4119}
4120
4121int dev_vprintk_emit(int level, const struct device *dev,
4122 const char *fmt, va_list args)
4123{
4124 char hdr[128];
4125 size_t hdrlen;
4126
4127 hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
4128
4129 return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
4130}
4131EXPORT_SYMBOL(dev_vprintk_emit);
4132
4133int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4134{
4135 va_list args;
4136 int r;
4137
4138 va_start(args, fmt);
4139
4140 r = dev_vprintk_emit(level, dev, fmt, args);
4141
4142 va_end(args);
4143
4144 return r;
4145}
4146EXPORT_SYMBOL(dev_printk_emit);
4147
4148static void __dev_printk(const char *level, const struct device *dev,
4149 struct va_format *vaf)
4150{
4151 if (dev)
4152 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4153 dev_driver_string(dev), dev_name(dev), vaf);
4154 else
4155 printk("%s(NULL device *): %pV", level, vaf);
4156}
4157
4158void dev_printk(const char *level, const struct device *dev,
4159 const char *fmt, ...)
4160{
4161 struct va_format vaf;
4162 va_list args;
4163
4164 va_start(args, fmt);
4165
4166 vaf.fmt = fmt;
4167 vaf.va = &args;
4168
4169 __dev_printk(level, dev, &vaf);
4170
4171 va_end(args);
4172}
4173EXPORT_SYMBOL(dev_printk);
4174
4175#define define_dev_printk_level(func, kern_level) \
4176void func(const struct device *dev, const char *fmt, ...) \
4177{ \
4178 struct va_format vaf; \
4179 va_list args; \
4180 \
4181 va_start(args, fmt); \
4182 \
4183 vaf.fmt = fmt; \
4184 vaf.va = &args; \
4185 \
4186 __dev_printk(kern_level, dev, &vaf); \
4187 \
4188 va_end(args); \
4189} \
4190EXPORT_SYMBOL(func);
4191
4192define_dev_printk_level(_dev_emerg, KERN_EMERG);
4193define_dev_printk_level(_dev_alert, KERN_ALERT);
4194define_dev_printk_level(_dev_crit, KERN_CRIT);
4195define_dev_printk_level(_dev_err, KERN_ERR);
4196define_dev_printk_level(_dev_warn, KERN_WARNING);
4197define_dev_printk_level(_dev_notice, KERN_NOTICE);
4198define_dev_printk_level(_dev_info, KERN_INFO);
4199
4200#endif
4201
4202/**
4203 * dev_err_probe - probe error check and log helper
4204 * @dev: the pointer to the struct device
4205 * @err: error value to test
4206 * @fmt: printf-style format string
4207 * @...: arguments as specified in the format string
4208 *
4209 * This helper implements common pattern present in probe functions for error
4210 * checking: print debug or error message depending if the error value is
4211 * -EPROBE_DEFER and propagate error upwards.
4212 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4213 * checked later by reading devices_deferred debugfs attribute.
4214 * It replaces code sequence:
4215 * if (err != -EPROBE_DEFER)
4216 * dev_err(dev, ...);
4217 * else
4218 * dev_dbg(dev, ...);
4219 * return err;
4220 * with
4221 * return dev_err_probe(dev, err, ...);
4222 *
4223 * Returns @err.
4224 *
4225 */
4226int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4227{
4228 struct va_format vaf;
4229 va_list args;
4230
4231 va_start(args, fmt);
4232 vaf.fmt = fmt;
4233 vaf.va = &args;
4234
4235 if (err != -EPROBE_DEFER) {
4236 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4237 } else {
4238 device_set_deferred_probe_reason(dev, &vaf);
4239 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4240 }
4241
4242 va_end(args);
4243
4244 return err;
4245}
4246EXPORT_SYMBOL_GPL(dev_err_probe);
4247
4248static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4249{
4250 return fwnode && !IS_ERR(fwnode->secondary);
4251}
4252
4253/**
4254 * set_primary_fwnode - Change the primary firmware node of a given device.
4255 * @dev: Device to handle.
4256 * @fwnode: New primary firmware node of the device.
4257 *
4258 * Set the device's firmware node pointer to @fwnode, but if a secondary
4259 * firmware node of the device is present, preserve it.
4260 */
4261void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4262{
4263 struct fwnode_handle *fn = dev->fwnode;
4264
4265 if (fwnode) {
4266 if (fwnode_is_primary(fn))
4267 fn = fn->secondary;
4268
4269 if (fn) {
4270 WARN_ON(fwnode->secondary);
4271 fwnode->secondary = fn;
4272 }
4273 dev->fwnode = fwnode;
4274 } else {
4275 if (fwnode_is_primary(fn)) {
4276 dev->fwnode = fn->secondary;
4277 fn->secondary = NULL;
4278 } else {
4279 dev->fwnode = NULL;
4280 }
4281 }
4282}
4283EXPORT_SYMBOL_GPL(set_primary_fwnode);
4284
4285/**
4286 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4287 * @dev: Device to handle.
4288 * @fwnode: New secondary firmware node of the device.
4289 *
4290 * If a primary firmware node of the device is present, set its secondary
4291 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4292 * @fwnode.
4293 */
4294void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4295{
4296 if (fwnode)
4297 fwnode->secondary = ERR_PTR(-ENODEV);
4298
4299 if (fwnode_is_primary(dev->fwnode))
4300 dev->fwnode->secondary = fwnode;
4301 else
4302 dev->fwnode = fwnode;
4303}
4304EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4305
4306/**
4307 * device_set_of_node_from_dev - reuse device-tree node of another device
4308 * @dev: device whose device-tree node is being set
4309 * @dev2: device whose device-tree node is being reused
4310 *
4311 * Takes another reference to the new device-tree node after first dropping
4312 * any reference held to the old node.
4313 */
4314void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4315{
4316 of_node_put(dev->of_node);
4317 dev->of_node = of_node_get(dev2->of_node);
4318 dev->of_node_reused = true;
4319}
4320EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4321
4322int device_match_name(struct device *dev, const void *name)
4323{
4324 return sysfs_streq(dev_name(dev), name);
4325}
4326EXPORT_SYMBOL_GPL(device_match_name);
4327
4328int device_match_of_node(struct device *dev, const void *np)
4329{
4330 return dev->of_node == np;
4331}
4332EXPORT_SYMBOL_GPL(device_match_of_node);
4333
4334int device_match_fwnode(struct device *dev, const void *fwnode)
4335{
4336 return dev_fwnode(dev) == fwnode;
4337}
4338EXPORT_SYMBOL_GPL(device_match_fwnode);
4339
4340int device_match_devt(struct device *dev, const void *pdevt)
4341{
4342 return dev->devt == *(dev_t *)pdevt;
4343}
4344EXPORT_SYMBOL_GPL(device_match_devt);
4345
4346int device_match_acpi_dev(struct device *dev, const void *adev)
4347{
4348 return ACPI_COMPANION(dev) == adev;
4349}
4350EXPORT_SYMBOL(device_match_acpi_dev);
4351
4352int device_match_any(struct device *dev, const void *unused)
4353{
4354 return 1;
4355}
4356EXPORT_SYMBOL_GPL(device_match_any);