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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/sched/mm.h>
30#include <linux/sysfs.h>
31#include <linux/dma-map-ops.h> /* for dma_default_coherent */
32
33#include "base.h"
34#include "power/power.h"
35
36#ifdef CONFIG_SYSFS_DEPRECATED
37#ifdef CONFIG_SYSFS_DEPRECATED_V2
38long sysfs_deprecated = 1;
39#else
40long sysfs_deprecated = 0;
41#endif
42static int __init sysfs_deprecated_setup(char *arg)
43{
44 return kstrtol(arg, 10, &sysfs_deprecated);
45}
46early_param("sysfs.deprecated", sysfs_deprecated_setup);
47#endif
48
49/* Device links support. */
50static LIST_HEAD(deferred_sync);
51static unsigned int defer_sync_state_count = 1;
52static DEFINE_MUTEX(fwnode_link_lock);
53static bool fw_devlink_is_permissive(void);
54static bool fw_devlink_drv_reg_done;
55
56/**
57 * fwnode_link_add - Create a link between two fwnode_handles.
58 * @con: Consumer end of the link.
59 * @sup: Supplier end of the link.
60 *
61 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
62 * represents the detail that the firmware lists @sup fwnode as supplying a
63 * resource to @con.
64 *
65 * The driver core will use the fwnode link to create a device link between the
66 * two device objects corresponding to @con and @sup when they are created. The
67 * driver core will automatically delete the fwnode link between @con and @sup
68 * after doing that.
69 *
70 * Attempts to create duplicate links between the same pair of fwnode handles
71 * are ignored and there is no reference counting.
72 */
73int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
74{
75 struct fwnode_link *link;
76 int ret = 0;
77
78 mutex_lock(&fwnode_link_lock);
79
80 list_for_each_entry(link, &sup->consumers, s_hook)
81 if (link->consumer == con)
82 goto out;
83
84 link = kzalloc(sizeof(*link), GFP_KERNEL);
85 if (!link) {
86 ret = -ENOMEM;
87 goto out;
88 }
89
90 link->supplier = sup;
91 INIT_LIST_HEAD(&link->s_hook);
92 link->consumer = con;
93 INIT_LIST_HEAD(&link->c_hook);
94
95 list_add(&link->s_hook, &sup->consumers);
96 list_add(&link->c_hook, &con->suppliers);
97out:
98 mutex_unlock(&fwnode_link_lock);
99
100 return ret;
101}
102
103/**
104 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
105 * @fwnode: fwnode whose supplier links need to be deleted
106 *
107 * Deletes all supplier links connecting directly to @fwnode.
108 */
109static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
110{
111 struct fwnode_link *link, *tmp;
112
113 mutex_lock(&fwnode_link_lock);
114 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
115 list_del(&link->s_hook);
116 list_del(&link->c_hook);
117 kfree(link);
118 }
119 mutex_unlock(&fwnode_link_lock);
120}
121
122/**
123 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
124 * @fwnode: fwnode whose consumer links need to be deleted
125 *
126 * Deletes all consumer links connecting directly to @fwnode.
127 */
128static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
129{
130 struct fwnode_link *link, *tmp;
131
132 mutex_lock(&fwnode_link_lock);
133 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
134 list_del(&link->s_hook);
135 list_del(&link->c_hook);
136 kfree(link);
137 }
138 mutex_unlock(&fwnode_link_lock);
139}
140
141/**
142 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
143 * @fwnode: fwnode whose links needs to be deleted
144 *
145 * Deletes all links connecting directly to a fwnode.
146 */
147void fwnode_links_purge(struct fwnode_handle *fwnode)
148{
149 fwnode_links_purge_suppliers(fwnode);
150 fwnode_links_purge_consumers(fwnode);
151}
152
153void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
154{
155 struct fwnode_handle *child;
156
157 /* Don't purge consumer links of an added child */
158 if (fwnode->dev)
159 return;
160
161 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
162 fwnode_links_purge_consumers(fwnode);
163
164 fwnode_for_each_available_child_node(fwnode, child)
165 fw_devlink_purge_absent_suppliers(child);
166}
167EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
168
169#ifdef CONFIG_SRCU
170static DEFINE_MUTEX(device_links_lock);
171DEFINE_STATIC_SRCU(device_links_srcu);
172
173static inline void device_links_write_lock(void)
174{
175 mutex_lock(&device_links_lock);
176}
177
178static inline void device_links_write_unlock(void)
179{
180 mutex_unlock(&device_links_lock);
181}
182
183int device_links_read_lock(void) __acquires(&device_links_srcu)
184{
185 return srcu_read_lock(&device_links_srcu);
186}
187
188void device_links_read_unlock(int idx) __releases(&device_links_srcu)
189{
190 srcu_read_unlock(&device_links_srcu, idx);
191}
192
193int device_links_read_lock_held(void)
194{
195 return srcu_read_lock_held(&device_links_srcu);
196}
197
198static void device_link_synchronize_removal(void)
199{
200 synchronize_srcu(&device_links_srcu);
201}
202
203static void device_link_remove_from_lists(struct device_link *link)
204{
205 list_del_rcu(&link->s_node);
206 list_del_rcu(&link->c_node);
207}
208#else /* !CONFIG_SRCU */
209static DECLARE_RWSEM(device_links_lock);
210
211static inline void device_links_write_lock(void)
212{
213 down_write(&device_links_lock);
214}
215
216static inline void device_links_write_unlock(void)
217{
218 up_write(&device_links_lock);
219}
220
221int device_links_read_lock(void)
222{
223 down_read(&device_links_lock);
224 return 0;
225}
226
227void device_links_read_unlock(int not_used)
228{
229 up_read(&device_links_lock);
230}
231
232#ifdef CONFIG_DEBUG_LOCK_ALLOC
233int device_links_read_lock_held(void)
234{
235 return lockdep_is_held(&device_links_lock);
236}
237#endif
238
239static inline void device_link_synchronize_removal(void)
240{
241}
242
243static void device_link_remove_from_lists(struct device_link *link)
244{
245 list_del(&link->s_node);
246 list_del(&link->c_node);
247}
248#endif /* !CONFIG_SRCU */
249
250static bool device_is_ancestor(struct device *dev, struct device *target)
251{
252 while (target->parent) {
253 target = target->parent;
254 if (dev == target)
255 return true;
256 }
257 return false;
258}
259
260/**
261 * device_is_dependent - Check if one device depends on another one
262 * @dev: Device to check dependencies for.
263 * @target: Device to check against.
264 *
265 * Check if @target depends on @dev or any device dependent on it (its child or
266 * its consumer etc). Return 1 if that is the case or 0 otherwise.
267 */
268int device_is_dependent(struct device *dev, void *target)
269{
270 struct device_link *link;
271 int ret;
272
273 /*
274 * The "ancestors" check is needed to catch the case when the target
275 * device has not been completely initialized yet and it is still
276 * missing from the list of children of its parent device.
277 */
278 if (dev == target || device_is_ancestor(dev, target))
279 return 1;
280
281 ret = device_for_each_child(dev, target, device_is_dependent);
282 if (ret)
283 return ret;
284
285 list_for_each_entry(link, &dev->links.consumers, s_node) {
286 if ((link->flags & ~DL_FLAG_INFERRED) ==
287 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
288 continue;
289
290 if (link->consumer == target)
291 return 1;
292
293 ret = device_is_dependent(link->consumer, target);
294 if (ret)
295 break;
296 }
297 return ret;
298}
299
300static void device_link_init_status(struct device_link *link,
301 struct device *consumer,
302 struct device *supplier)
303{
304 switch (supplier->links.status) {
305 case DL_DEV_PROBING:
306 switch (consumer->links.status) {
307 case DL_DEV_PROBING:
308 /*
309 * A consumer driver can create a link to a supplier
310 * that has not completed its probing yet as long as it
311 * knows that the supplier is already functional (for
312 * example, it has just acquired some resources from the
313 * supplier).
314 */
315 link->status = DL_STATE_CONSUMER_PROBE;
316 break;
317 default:
318 link->status = DL_STATE_DORMANT;
319 break;
320 }
321 break;
322 case DL_DEV_DRIVER_BOUND:
323 switch (consumer->links.status) {
324 case DL_DEV_PROBING:
325 link->status = DL_STATE_CONSUMER_PROBE;
326 break;
327 case DL_DEV_DRIVER_BOUND:
328 link->status = DL_STATE_ACTIVE;
329 break;
330 default:
331 link->status = DL_STATE_AVAILABLE;
332 break;
333 }
334 break;
335 case DL_DEV_UNBINDING:
336 link->status = DL_STATE_SUPPLIER_UNBIND;
337 break;
338 default:
339 link->status = DL_STATE_DORMANT;
340 break;
341 }
342}
343
344static int device_reorder_to_tail(struct device *dev, void *not_used)
345{
346 struct device_link *link;
347
348 /*
349 * Devices that have not been registered yet will be put to the ends
350 * of the lists during the registration, so skip them here.
351 */
352 if (device_is_registered(dev))
353 devices_kset_move_last(dev);
354
355 if (device_pm_initialized(dev))
356 device_pm_move_last(dev);
357
358 device_for_each_child(dev, NULL, device_reorder_to_tail);
359 list_for_each_entry(link, &dev->links.consumers, s_node) {
360 if ((link->flags & ~DL_FLAG_INFERRED) ==
361 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
362 continue;
363 device_reorder_to_tail(link->consumer, NULL);
364 }
365
366 return 0;
367}
368
369/**
370 * device_pm_move_to_tail - Move set of devices to the end of device lists
371 * @dev: Device to move
372 *
373 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
374 *
375 * It moves the @dev along with all of its children and all of its consumers
376 * to the ends of the device_kset and dpm_list, recursively.
377 */
378void device_pm_move_to_tail(struct device *dev)
379{
380 int idx;
381
382 idx = device_links_read_lock();
383 device_pm_lock();
384 device_reorder_to_tail(dev, NULL);
385 device_pm_unlock();
386 device_links_read_unlock(idx);
387}
388
389#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
390
391static ssize_t status_show(struct device *dev,
392 struct device_attribute *attr, char *buf)
393{
394 const char *output;
395
396 switch (to_devlink(dev)->status) {
397 case DL_STATE_NONE:
398 output = "not tracked";
399 break;
400 case DL_STATE_DORMANT:
401 output = "dormant";
402 break;
403 case DL_STATE_AVAILABLE:
404 output = "available";
405 break;
406 case DL_STATE_CONSUMER_PROBE:
407 output = "consumer probing";
408 break;
409 case DL_STATE_ACTIVE:
410 output = "active";
411 break;
412 case DL_STATE_SUPPLIER_UNBIND:
413 output = "supplier unbinding";
414 break;
415 default:
416 output = "unknown";
417 break;
418 }
419
420 return sysfs_emit(buf, "%s\n", output);
421}
422static DEVICE_ATTR_RO(status);
423
424static ssize_t auto_remove_on_show(struct device *dev,
425 struct device_attribute *attr, char *buf)
426{
427 struct device_link *link = to_devlink(dev);
428 const char *output;
429
430 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
431 output = "supplier unbind";
432 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
433 output = "consumer unbind";
434 else
435 output = "never";
436
437 return sysfs_emit(buf, "%s\n", output);
438}
439static DEVICE_ATTR_RO(auto_remove_on);
440
441static ssize_t runtime_pm_show(struct device *dev,
442 struct device_attribute *attr, char *buf)
443{
444 struct device_link *link = to_devlink(dev);
445
446 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
447}
448static DEVICE_ATTR_RO(runtime_pm);
449
450static ssize_t sync_state_only_show(struct device *dev,
451 struct device_attribute *attr, char *buf)
452{
453 struct device_link *link = to_devlink(dev);
454
455 return sysfs_emit(buf, "%d\n",
456 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
457}
458static DEVICE_ATTR_RO(sync_state_only);
459
460static struct attribute *devlink_attrs[] = {
461 &dev_attr_status.attr,
462 &dev_attr_auto_remove_on.attr,
463 &dev_attr_runtime_pm.attr,
464 &dev_attr_sync_state_only.attr,
465 NULL,
466};
467ATTRIBUTE_GROUPS(devlink);
468
469static void device_link_release_fn(struct work_struct *work)
470{
471 struct device_link *link = container_of(work, struct device_link, rm_work);
472
473 /* Ensure that all references to the link object have been dropped. */
474 device_link_synchronize_removal();
475
476 while (refcount_dec_not_one(&link->rpm_active))
477 pm_runtime_put(link->supplier);
478
479 put_device(link->consumer);
480 put_device(link->supplier);
481 kfree(link);
482}
483
484static void devlink_dev_release(struct device *dev)
485{
486 struct device_link *link = to_devlink(dev);
487
488 INIT_WORK(&link->rm_work, device_link_release_fn);
489 /*
490 * It may take a while to complete this work because of the SRCU
491 * synchronization in device_link_release_fn() and if the consumer or
492 * supplier devices get deleted when it runs, so put it into the "long"
493 * workqueue.
494 */
495 queue_work(system_long_wq, &link->rm_work);
496}
497
498static struct class devlink_class = {
499 .name = "devlink",
500 .owner = THIS_MODULE,
501 .dev_groups = devlink_groups,
502 .dev_release = devlink_dev_release,
503};
504
505static int devlink_add_symlinks(struct device *dev,
506 struct class_interface *class_intf)
507{
508 int ret;
509 size_t len;
510 struct device_link *link = to_devlink(dev);
511 struct device *sup = link->supplier;
512 struct device *con = link->consumer;
513 char *buf;
514
515 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
516 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
517 len += strlen(":");
518 len += strlen("supplier:") + 1;
519 buf = kzalloc(len, GFP_KERNEL);
520 if (!buf)
521 return -ENOMEM;
522
523 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
524 if (ret)
525 goto out;
526
527 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
528 if (ret)
529 goto err_con;
530
531 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
532 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
533 if (ret)
534 goto err_con_dev;
535
536 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
537 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
538 if (ret)
539 goto err_sup_dev;
540
541 goto out;
542
543err_sup_dev:
544 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
545 sysfs_remove_link(&sup->kobj, buf);
546err_con_dev:
547 sysfs_remove_link(&link->link_dev.kobj, "consumer");
548err_con:
549 sysfs_remove_link(&link->link_dev.kobj, "supplier");
550out:
551 kfree(buf);
552 return ret;
553}
554
555static void devlink_remove_symlinks(struct device *dev,
556 struct class_interface *class_intf)
557{
558 struct device_link *link = to_devlink(dev);
559 size_t len;
560 struct device *sup = link->supplier;
561 struct device *con = link->consumer;
562 char *buf;
563
564 sysfs_remove_link(&link->link_dev.kobj, "consumer");
565 sysfs_remove_link(&link->link_dev.kobj, "supplier");
566
567 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
568 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
569 len += strlen(":");
570 len += strlen("supplier:") + 1;
571 buf = kzalloc(len, GFP_KERNEL);
572 if (!buf) {
573 WARN(1, "Unable to properly free device link symlinks!\n");
574 return;
575 }
576
577 if (device_is_registered(con)) {
578 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
579 sysfs_remove_link(&con->kobj, buf);
580 }
581 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
582 sysfs_remove_link(&sup->kobj, buf);
583 kfree(buf);
584}
585
586static struct class_interface devlink_class_intf = {
587 .class = &devlink_class,
588 .add_dev = devlink_add_symlinks,
589 .remove_dev = devlink_remove_symlinks,
590};
591
592static int __init devlink_class_init(void)
593{
594 int ret;
595
596 ret = class_register(&devlink_class);
597 if (ret)
598 return ret;
599
600 ret = class_interface_register(&devlink_class_intf);
601 if (ret)
602 class_unregister(&devlink_class);
603
604 return ret;
605}
606postcore_initcall(devlink_class_init);
607
608#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
609 DL_FLAG_AUTOREMOVE_SUPPLIER | \
610 DL_FLAG_AUTOPROBE_CONSUMER | \
611 DL_FLAG_SYNC_STATE_ONLY | \
612 DL_FLAG_INFERRED)
613
614#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
615 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
616
617/**
618 * device_link_add - Create a link between two devices.
619 * @consumer: Consumer end of the link.
620 * @supplier: Supplier end of the link.
621 * @flags: Link flags.
622 *
623 * The caller is responsible for the proper synchronization of the link creation
624 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
625 * runtime PM framework to take the link into account. Second, if the
626 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
627 * be forced into the active meta state and reference-counted upon the creation
628 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
629 * ignored.
630 *
631 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
632 * expected to release the link returned by it directly with the help of either
633 * device_link_del() or device_link_remove().
634 *
635 * If that flag is not set, however, the caller of this function is handing the
636 * management of the link over to the driver core entirely and its return value
637 * can only be used to check whether or not the link is present. In that case,
638 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
639 * flags can be used to indicate to the driver core when the link can be safely
640 * deleted. Namely, setting one of them in @flags indicates to the driver core
641 * that the link is not going to be used (by the given caller of this function)
642 * after unbinding the consumer or supplier driver, respectively, from its
643 * device, so the link can be deleted at that point. If none of them is set,
644 * the link will be maintained until one of the devices pointed to by it (either
645 * the consumer or the supplier) is unregistered.
646 *
647 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
648 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
649 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
650 * be used to request the driver core to automatically probe for a consumer
651 * driver after successfully binding a driver to the supplier device.
652 *
653 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
654 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
655 * the same time is invalid and will cause NULL to be returned upfront.
656 * However, if a device link between the given @consumer and @supplier pair
657 * exists already when this function is called for them, the existing link will
658 * be returned regardless of its current type and status (the link's flags may
659 * be modified then). The caller of this function is then expected to treat
660 * the link as though it has just been created, so (in particular) if
661 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
662 * explicitly when not needed any more (as stated above).
663 *
664 * A side effect of the link creation is re-ordering of dpm_list and the
665 * devices_kset list by moving the consumer device and all devices depending
666 * on it to the ends of these lists (that does not happen to devices that have
667 * not been registered when this function is called).
668 *
669 * The supplier device is required to be registered when this function is called
670 * and NULL will be returned if that is not the case. The consumer device need
671 * not be registered, however.
672 */
673struct device_link *device_link_add(struct device *consumer,
674 struct device *supplier, u32 flags)
675{
676 struct device_link *link;
677
678 if (!consumer || !supplier || consumer == supplier ||
679 flags & ~DL_ADD_VALID_FLAGS ||
680 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
681 (flags & DL_FLAG_SYNC_STATE_ONLY &&
682 (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) ||
683 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
684 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
685 DL_FLAG_AUTOREMOVE_SUPPLIER)))
686 return NULL;
687
688 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
689 if (pm_runtime_get_sync(supplier) < 0) {
690 pm_runtime_put_noidle(supplier);
691 return NULL;
692 }
693 }
694
695 if (!(flags & DL_FLAG_STATELESS))
696 flags |= DL_FLAG_MANAGED;
697
698 device_links_write_lock();
699 device_pm_lock();
700
701 /*
702 * If the supplier has not been fully registered yet or there is a
703 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
704 * the supplier already in the graph, return NULL. If the link is a
705 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
706 * because it only affects sync_state() callbacks.
707 */
708 if (!device_pm_initialized(supplier)
709 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
710 device_is_dependent(consumer, supplier))) {
711 link = NULL;
712 goto out;
713 }
714
715 /*
716 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
717 * So, only create it if the consumer hasn't probed yet.
718 */
719 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
720 consumer->links.status != DL_DEV_NO_DRIVER &&
721 consumer->links.status != DL_DEV_PROBING) {
722 link = NULL;
723 goto out;
724 }
725
726 /*
727 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
728 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
729 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
730 */
731 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
732 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
733
734 list_for_each_entry(link, &supplier->links.consumers, s_node) {
735 if (link->consumer != consumer)
736 continue;
737
738 if (link->flags & DL_FLAG_INFERRED &&
739 !(flags & DL_FLAG_INFERRED))
740 link->flags &= ~DL_FLAG_INFERRED;
741
742 if (flags & DL_FLAG_PM_RUNTIME) {
743 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
744 pm_runtime_new_link(consumer);
745 link->flags |= DL_FLAG_PM_RUNTIME;
746 }
747 if (flags & DL_FLAG_RPM_ACTIVE)
748 refcount_inc(&link->rpm_active);
749 }
750
751 if (flags & DL_FLAG_STATELESS) {
752 kref_get(&link->kref);
753 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
754 !(link->flags & DL_FLAG_STATELESS)) {
755 link->flags |= DL_FLAG_STATELESS;
756 goto reorder;
757 } else {
758 link->flags |= DL_FLAG_STATELESS;
759 goto out;
760 }
761 }
762
763 /*
764 * If the life time of the link following from the new flags is
765 * longer than indicated by the flags of the existing link,
766 * update the existing link to stay around longer.
767 */
768 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
769 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
770 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
771 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
772 }
773 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
774 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
775 DL_FLAG_AUTOREMOVE_SUPPLIER);
776 }
777 if (!(link->flags & DL_FLAG_MANAGED)) {
778 kref_get(&link->kref);
779 link->flags |= DL_FLAG_MANAGED;
780 device_link_init_status(link, consumer, supplier);
781 }
782 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
783 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
784 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
785 goto reorder;
786 }
787
788 goto out;
789 }
790
791 link = kzalloc(sizeof(*link), GFP_KERNEL);
792 if (!link)
793 goto out;
794
795 refcount_set(&link->rpm_active, 1);
796
797 get_device(supplier);
798 link->supplier = supplier;
799 INIT_LIST_HEAD(&link->s_node);
800 get_device(consumer);
801 link->consumer = consumer;
802 INIT_LIST_HEAD(&link->c_node);
803 link->flags = flags;
804 kref_init(&link->kref);
805
806 link->link_dev.class = &devlink_class;
807 device_set_pm_not_required(&link->link_dev);
808 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
809 dev_bus_name(supplier), dev_name(supplier),
810 dev_bus_name(consumer), dev_name(consumer));
811 if (device_register(&link->link_dev)) {
812 put_device(consumer);
813 put_device(supplier);
814 kfree(link);
815 link = NULL;
816 goto out;
817 }
818
819 if (flags & DL_FLAG_PM_RUNTIME) {
820 if (flags & DL_FLAG_RPM_ACTIVE)
821 refcount_inc(&link->rpm_active);
822
823 pm_runtime_new_link(consumer);
824 }
825
826 /* Determine the initial link state. */
827 if (flags & DL_FLAG_STATELESS)
828 link->status = DL_STATE_NONE;
829 else
830 device_link_init_status(link, consumer, supplier);
831
832 /*
833 * Some callers expect the link creation during consumer driver probe to
834 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
835 */
836 if (link->status == DL_STATE_CONSUMER_PROBE &&
837 flags & DL_FLAG_PM_RUNTIME)
838 pm_runtime_resume(supplier);
839
840 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
841 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
842
843 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
844 dev_dbg(consumer,
845 "Linked as a sync state only consumer to %s\n",
846 dev_name(supplier));
847 goto out;
848 }
849
850reorder:
851 /*
852 * Move the consumer and all of the devices depending on it to the end
853 * of dpm_list and the devices_kset list.
854 *
855 * It is necessary to hold dpm_list locked throughout all that or else
856 * we may end up suspending with a wrong ordering of it.
857 */
858 device_reorder_to_tail(consumer, NULL);
859
860 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
861
862out:
863 device_pm_unlock();
864 device_links_write_unlock();
865
866 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
867 pm_runtime_put(supplier);
868
869 return link;
870}
871EXPORT_SYMBOL_GPL(device_link_add);
872
873static void __device_link_del(struct kref *kref)
874{
875 struct device_link *link = container_of(kref, struct device_link, kref);
876
877 dev_dbg(link->consumer, "Dropping the link to %s\n",
878 dev_name(link->supplier));
879
880 pm_runtime_drop_link(link);
881
882 device_link_remove_from_lists(link);
883 device_unregister(&link->link_dev);
884}
885
886static void device_link_put_kref(struct device_link *link)
887{
888 if (link->flags & DL_FLAG_STATELESS)
889 kref_put(&link->kref, __device_link_del);
890 else if (!device_is_registered(link->consumer))
891 __device_link_del(&link->kref);
892 else
893 WARN(1, "Unable to drop a managed device link reference\n");
894}
895
896/**
897 * device_link_del - Delete a stateless link between two devices.
898 * @link: Device link to delete.
899 *
900 * The caller must ensure proper synchronization of this function with runtime
901 * PM. If the link was added multiple times, it needs to be deleted as often.
902 * Care is required for hotplugged devices: Their links are purged on removal
903 * and calling device_link_del() is then no longer allowed.
904 */
905void device_link_del(struct device_link *link)
906{
907 device_links_write_lock();
908 device_link_put_kref(link);
909 device_links_write_unlock();
910}
911EXPORT_SYMBOL_GPL(device_link_del);
912
913/**
914 * device_link_remove - Delete a stateless link between two devices.
915 * @consumer: Consumer end of the link.
916 * @supplier: Supplier end of the link.
917 *
918 * The caller must ensure proper synchronization of this function with runtime
919 * PM.
920 */
921void device_link_remove(void *consumer, struct device *supplier)
922{
923 struct device_link *link;
924
925 if (WARN_ON(consumer == supplier))
926 return;
927
928 device_links_write_lock();
929
930 list_for_each_entry(link, &supplier->links.consumers, s_node) {
931 if (link->consumer == consumer) {
932 device_link_put_kref(link);
933 break;
934 }
935 }
936
937 device_links_write_unlock();
938}
939EXPORT_SYMBOL_GPL(device_link_remove);
940
941static void device_links_missing_supplier(struct device *dev)
942{
943 struct device_link *link;
944
945 list_for_each_entry(link, &dev->links.suppliers, c_node) {
946 if (link->status != DL_STATE_CONSUMER_PROBE)
947 continue;
948
949 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
950 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
951 } else {
952 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
953 WRITE_ONCE(link->status, DL_STATE_DORMANT);
954 }
955 }
956}
957
958/**
959 * device_links_check_suppliers - Check presence of supplier drivers.
960 * @dev: Consumer device.
961 *
962 * Check links from this device to any suppliers. Walk the list of the device's
963 * links to suppliers and see if all of them are available. If not, simply
964 * return -EPROBE_DEFER.
965 *
966 * We need to guarantee that the supplier will not go away after the check has
967 * been positive here. It only can go away in __device_release_driver() and
968 * that function checks the device's links to consumers. This means we need to
969 * mark the link as "consumer probe in progress" to make the supplier removal
970 * wait for us to complete (or bad things may happen).
971 *
972 * Links without the DL_FLAG_MANAGED flag set are ignored.
973 */
974int device_links_check_suppliers(struct device *dev)
975{
976 struct device_link *link;
977 int ret = 0;
978
979 /*
980 * Device waiting for supplier to become available is not allowed to
981 * probe.
982 */
983 mutex_lock(&fwnode_link_lock);
984 if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
985 !fw_devlink_is_permissive()) {
986 dev_dbg(dev, "probe deferral - wait for supplier %pfwP\n",
987 list_first_entry(&dev->fwnode->suppliers,
988 struct fwnode_link,
989 c_hook)->supplier);
990 mutex_unlock(&fwnode_link_lock);
991 return -EPROBE_DEFER;
992 }
993 mutex_unlock(&fwnode_link_lock);
994
995 device_links_write_lock();
996
997 list_for_each_entry(link, &dev->links.suppliers, c_node) {
998 if (!(link->flags & DL_FLAG_MANAGED))
999 continue;
1000
1001 if (link->status != DL_STATE_AVAILABLE &&
1002 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1003 device_links_missing_supplier(dev);
1004 dev_dbg(dev, "probe deferral - supplier %s not ready\n",
1005 dev_name(link->supplier));
1006 ret = -EPROBE_DEFER;
1007 break;
1008 }
1009 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1010 }
1011 dev->links.status = DL_DEV_PROBING;
1012
1013 device_links_write_unlock();
1014 return ret;
1015}
1016
1017/**
1018 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1019 * @dev: Device to call sync_state() on
1020 * @list: List head to queue the @dev on
1021 *
1022 * Queues a device for a sync_state() callback when the device links write lock
1023 * isn't held. This allows the sync_state() execution flow to use device links
1024 * APIs. The caller must ensure this function is called with
1025 * device_links_write_lock() held.
1026 *
1027 * This function does a get_device() to make sure the device is not freed while
1028 * on this list.
1029 *
1030 * So the caller must also ensure that device_links_flush_sync_list() is called
1031 * as soon as the caller releases device_links_write_lock(). This is necessary
1032 * to make sure the sync_state() is called in a timely fashion and the
1033 * put_device() is called on this device.
1034 */
1035static void __device_links_queue_sync_state(struct device *dev,
1036 struct list_head *list)
1037{
1038 struct device_link *link;
1039
1040 if (!dev_has_sync_state(dev))
1041 return;
1042 if (dev->state_synced)
1043 return;
1044
1045 list_for_each_entry(link, &dev->links.consumers, s_node) {
1046 if (!(link->flags & DL_FLAG_MANAGED))
1047 continue;
1048 if (link->status != DL_STATE_ACTIVE)
1049 return;
1050 }
1051
1052 /*
1053 * Set the flag here to avoid adding the same device to a list more
1054 * than once. This can happen if new consumers get added to the device
1055 * and probed before the list is flushed.
1056 */
1057 dev->state_synced = true;
1058
1059 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1060 return;
1061
1062 get_device(dev);
1063 list_add_tail(&dev->links.defer_sync, list);
1064}
1065
1066/**
1067 * device_links_flush_sync_list - Call sync_state() on a list of devices
1068 * @list: List of devices to call sync_state() on
1069 * @dont_lock_dev: Device for which lock is already held by the caller
1070 *
1071 * Calls sync_state() on all the devices that have been queued for it. This
1072 * function is used in conjunction with __device_links_queue_sync_state(). The
1073 * @dont_lock_dev parameter is useful when this function is called from a
1074 * context where a device lock is already held.
1075 */
1076static void device_links_flush_sync_list(struct list_head *list,
1077 struct device *dont_lock_dev)
1078{
1079 struct device *dev, *tmp;
1080
1081 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1082 list_del_init(&dev->links.defer_sync);
1083
1084 if (dev != dont_lock_dev)
1085 device_lock(dev);
1086
1087 if (dev->bus->sync_state)
1088 dev->bus->sync_state(dev);
1089 else if (dev->driver && dev->driver->sync_state)
1090 dev->driver->sync_state(dev);
1091
1092 if (dev != dont_lock_dev)
1093 device_unlock(dev);
1094
1095 put_device(dev);
1096 }
1097}
1098
1099void device_links_supplier_sync_state_pause(void)
1100{
1101 device_links_write_lock();
1102 defer_sync_state_count++;
1103 device_links_write_unlock();
1104}
1105
1106void device_links_supplier_sync_state_resume(void)
1107{
1108 struct device *dev, *tmp;
1109 LIST_HEAD(sync_list);
1110
1111 device_links_write_lock();
1112 if (!defer_sync_state_count) {
1113 WARN(true, "Unmatched sync_state pause/resume!");
1114 goto out;
1115 }
1116 defer_sync_state_count--;
1117 if (defer_sync_state_count)
1118 goto out;
1119
1120 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1121 /*
1122 * Delete from deferred_sync list before queuing it to
1123 * sync_list because defer_sync is used for both lists.
1124 */
1125 list_del_init(&dev->links.defer_sync);
1126 __device_links_queue_sync_state(dev, &sync_list);
1127 }
1128out:
1129 device_links_write_unlock();
1130
1131 device_links_flush_sync_list(&sync_list, NULL);
1132}
1133
1134static int sync_state_resume_initcall(void)
1135{
1136 device_links_supplier_sync_state_resume();
1137 return 0;
1138}
1139late_initcall(sync_state_resume_initcall);
1140
1141static void __device_links_supplier_defer_sync(struct device *sup)
1142{
1143 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1144 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1145}
1146
1147static void device_link_drop_managed(struct device_link *link)
1148{
1149 link->flags &= ~DL_FLAG_MANAGED;
1150 WRITE_ONCE(link->status, DL_STATE_NONE);
1151 kref_put(&link->kref, __device_link_del);
1152}
1153
1154static ssize_t waiting_for_supplier_show(struct device *dev,
1155 struct device_attribute *attr,
1156 char *buf)
1157{
1158 bool val;
1159
1160 device_lock(dev);
1161 val = !list_empty(&dev->fwnode->suppliers);
1162 device_unlock(dev);
1163 return sysfs_emit(buf, "%u\n", val);
1164}
1165static DEVICE_ATTR_RO(waiting_for_supplier);
1166
1167/**
1168 * device_links_force_bind - Prepares device to be force bound
1169 * @dev: Consumer device.
1170 *
1171 * device_bind_driver() force binds a device to a driver without calling any
1172 * driver probe functions. So the consumer really isn't going to wait for any
1173 * supplier before it's bound to the driver. We still want the device link
1174 * states to be sensible when this happens.
1175 *
1176 * In preparation for device_bind_driver(), this function goes through each
1177 * supplier device links and checks if the supplier is bound. If it is, then
1178 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1179 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1180 */
1181void device_links_force_bind(struct device *dev)
1182{
1183 struct device_link *link, *ln;
1184
1185 device_links_write_lock();
1186
1187 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1188 if (!(link->flags & DL_FLAG_MANAGED))
1189 continue;
1190
1191 if (link->status != DL_STATE_AVAILABLE) {
1192 device_link_drop_managed(link);
1193 continue;
1194 }
1195 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1196 }
1197 dev->links.status = DL_DEV_PROBING;
1198
1199 device_links_write_unlock();
1200}
1201
1202/**
1203 * device_links_driver_bound - Update device links after probing its driver.
1204 * @dev: Device to update the links for.
1205 *
1206 * The probe has been successful, so update links from this device to any
1207 * consumers by changing their status to "available".
1208 *
1209 * Also change the status of @dev's links to suppliers to "active".
1210 *
1211 * Links without the DL_FLAG_MANAGED flag set are ignored.
1212 */
1213void device_links_driver_bound(struct device *dev)
1214{
1215 struct device_link *link, *ln;
1216 LIST_HEAD(sync_list);
1217
1218 /*
1219 * If a device binds successfully, it's expected to have created all
1220 * the device links it needs to or make new device links as it needs
1221 * them. So, fw_devlink no longer needs to create device links to any
1222 * of the device's suppliers.
1223 *
1224 * Also, if a child firmware node of this bound device is not added as
1225 * a device by now, assume it is never going to be added and make sure
1226 * other devices don't defer probe indefinitely by waiting for such a
1227 * child device.
1228 */
1229 if (dev->fwnode && dev->fwnode->dev == dev) {
1230 struct fwnode_handle *child;
1231 fwnode_links_purge_suppliers(dev->fwnode);
1232 fwnode_for_each_available_child_node(dev->fwnode, child)
1233 fw_devlink_purge_absent_suppliers(child);
1234 }
1235 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1236
1237 device_links_write_lock();
1238
1239 list_for_each_entry(link, &dev->links.consumers, s_node) {
1240 if (!(link->flags & DL_FLAG_MANAGED))
1241 continue;
1242
1243 /*
1244 * Links created during consumer probe may be in the "consumer
1245 * probe" state to start with if the supplier is still probing
1246 * when they are created and they may become "active" if the
1247 * consumer probe returns first. Skip them here.
1248 */
1249 if (link->status == DL_STATE_CONSUMER_PROBE ||
1250 link->status == DL_STATE_ACTIVE)
1251 continue;
1252
1253 WARN_ON(link->status != DL_STATE_DORMANT);
1254 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1255
1256 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1257 driver_deferred_probe_add(link->consumer);
1258 }
1259
1260 if (defer_sync_state_count)
1261 __device_links_supplier_defer_sync(dev);
1262 else
1263 __device_links_queue_sync_state(dev, &sync_list);
1264
1265 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1266 struct device *supplier;
1267
1268 if (!(link->flags & DL_FLAG_MANAGED))
1269 continue;
1270
1271 supplier = link->supplier;
1272 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1273 /*
1274 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1275 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1276 * save to drop the managed link completely.
1277 */
1278 device_link_drop_managed(link);
1279 } else {
1280 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1281 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1282 }
1283
1284 /*
1285 * This needs to be done even for the deleted
1286 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1287 * device link that was preventing the supplier from getting a
1288 * sync_state() call.
1289 */
1290 if (defer_sync_state_count)
1291 __device_links_supplier_defer_sync(supplier);
1292 else
1293 __device_links_queue_sync_state(supplier, &sync_list);
1294 }
1295
1296 dev->links.status = DL_DEV_DRIVER_BOUND;
1297
1298 device_links_write_unlock();
1299
1300 device_links_flush_sync_list(&sync_list, dev);
1301}
1302
1303/**
1304 * __device_links_no_driver - Update links of a device without a driver.
1305 * @dev: Device without a drvier.
1306 *
1307 * Delete all non-persistent links from this device to any suppliers.
1308 *
1309 * Persistent links stay around, but their status is changed to "available",
1310 * unless they already are in the "supplier unbind in progress" state in which
1311 * case they need not be updated.
1312 *
1313 * Links without the DL_FLAG_MANAGED flag set are ignored.
1314 */
1315static void __device_links_no_driver(struct device *dev)
1316{
1317 struct device_link *link, *ln;
1318
1319 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1320 if (!(link->flags & DL_FLAG_MANAGED))
1321 continue;
1322
1323 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1324 device_link_drop_managed(link);
1325 continue;
1326 }
1327
1328 if (link->status != DL_STATE_CONSUMER_PROBE &&
1329 link->status != DL_STATE_ACTIVE)
1330 continue;
1331
1332 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1333 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1334 } else {
1335 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1336 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1337 }
1338 }
1339
1340 dev->links.status = DL_DEV_NO_DRIVER;
1341}
1342
1343/**
1344 * device_links_no_driver - Update links after failing driver probe.
1345 * @dev: Device whose driver has just failed to probe.
1346 *
1347 * Clean up leftover links to consumers for @dev and invoke
1348 * %__device_links_no_driver() to update links to suppliers for it as
1349 * appropriate.
1350 *
1351 * Links without the DL_FLAG_MANAGED flag set are ignored.
1352 */
1353void device_links_no_driver(struct device *dev)
1354{
1355 struct device_link *link;
1356
1357 device_links_write_lock();
1358
1359 list_for_each_entry(link, &dev->links.consumers, s_node) {
1360 if (!(link->flags & DL_FLAG_MANAGED))
1361 continue;
1362
1363 /*
1364 * The probe has failed, so if the status of the link is
1365 * "consumer probe" or "active", it must have been added by
1366 * a probing consumer while this device was still probing.
1367 * Change its state to "dormant", as it represents a valid
1368 * relationship, but it is not functionally meaningful.
1369 */
1370 if (link->status == DL_STATE_CONSUMER_PROBE ||
1371 link->status == DL_STATE_ACTIVE)
1372 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1373 }
1374
1375 __device_links_no_driver(dev);
1376
1377 device_links_write_unlock();
1378}
1379
1380/**
1381 * device_links_driver_cleanup - Update links after driver removal.
1382 * @dev: Device whose driver has just gone away.
1383 *
1384 * Update links to consumers for @dev by changing their status to "dormant" and
1385 * invoke %__device_links_no_driver() to update links to suppliers for it as
1386 * appropriate.
1387 *
1388 * Links without the DL_FLAG_MANAGED flag set are ignored.
1389 */
1390void device_links_driver_cleanup(struct device *dev)
1391{
1392 struct device_link *link, *ln;
1393
1394 device_links_write_lock();
1395
1396 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1397 if (!(link->flags & DL_FLAG_MANAGED))
1398 continue;
1399
1400 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1401 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1402
1403 /*
1404 * autoremove the links between this @dev and its consumer
1405 * devices that are not active, i.e. where the link state
1406 * has moved to DL_STATE_SUPPLIER_UNBIND.
1407 */
1408 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1409 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1410 device_link_drop_managed(link);
1411
1412 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1413 }
1414
1415 list_del_init(&dev->links.defer_sync);
1416 __device_links_no_driver(dev);
1417
1418 device_links_write_unlock();
1419}
1420
1421/**
1422 * device_links_busy - Check if there are any busy links to consumers.
1423 * @dev: Device to check.
1424 *
1425 * Check each consumer of the device and return 'true' if its link's status
1426 * is one of "consumer probe" or "active" (meaning that the given consumer is
1427 * probing right now or its driver is present). Otherwise, change the link
1428 * state to "supplier unbind" to prevent the consumer from being probed
1429 * successfully going forward.
1430 *
1431 * Return 'false' if there are no probing or active consumers.
1432 *
1433 * Links without the DL_FLAG_MANAGED flag set are ignored.
1434 */
1435bool device_links_busy(struct device *dev)
1436{
1437 struct device_link *link;
1438 bool ret = false;
1439
1440 device_links_write_lock();
1441
1442 list_for_each_entry(link, &dev->links.consumers, s_node) {
1443 if (!(link->flags & DL_FLAG_MANAGED))
1444 continue;
1445
1446 if (link->status == DL_STATE_CONSUMER_PROBE
1447 || link->status == DL_STATE_ACTIVE) {
1448 ret = true;
1449 break;
1450 }
1451 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1452 }
1453
1454 dev->links.status = DL_DEV_UNBINDING;
1455
1456 device_links_write_unlock();
1457 return ret;
1458}
1459
1460/**
1461 * device_links_unbind_consumers - Force unbind consumers of the given device.
1462 * @dev: Device to unbind the consumers of.
1463 *
1464 * Walk the list of links to consumers for @dev and if any of them is in the
1465 * "consumer probe" state, wait for all device probes in progress to complete
1466 * and start over.
1467 *
1468 * If that's not the case, change the status of the link to "supplier unbind"
1469 * and check if the link was in the "active" state. If so, force the consumer
1470 * driver to unbind and start over (the consumer will not re-probe as we have
1471 * changed the state of the link already).
1472 *
1473 * Links without the DL_FLAG_MANAGED flag set are ignored.
1474 */
1475void device_links_unbind_consumers(struct device *dev)
1476{
1477 struct device_link *link;
1478
1479 start:
1480 device_links_write_lock();
1481
1482 list_for_each_entry(link, &dev->links.consumers, s_node) {
1483 enum device_link_state status;
1484
1485 if (!(link->flags & DL_FLAG_MANAGED) ||
1486 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1487 continue;
1488
1489 status = link->status;
1490 if (status == DL_STATE_CONSUMER_PROBE) {
1491 device_links_write_unlock();
1492
1493 wait_for_device_probe();
1494 goto start;
1495 }
1496 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1497 if (status == DL_STATE_ACTIVE) {
1498 struct device *consumer = link->consumer;
1499
1500 get_device(consumer);
1501
1502 device_links_write_unlock();
1503
1504 device_release_driver_internal(consumer, NULL,
1505 consumer->parent);
1506 put_device(consumer);
1507 goto start;
1508 }
1509 }
1510
1511 device_links_write_unlock();
1512}
1513
1514/**
1515 * device_links_purge - Delete existing links to other devices.
1516 * @dev: Target device.
1517 */
1518static void device_links_purge(struct device *dev)
1519{
1520 struct device_link *link, *ln;
1521
1522 if (dev->class == &devlink_class)
1523 return;
1524
1525 /*
1526 * Delete all of the remaining links from this device to any other
1527 * devices (either consumers or suppliers).
1528 */
1529 device_links_write_lock();
1530
1531 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1532 WARN_ON(link->status == DL_STATE_ACTIVE);
1533 __device_link_del(&link->kref);
1534 }
1535
1536 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1537 WARN_ON(link->status != DL_STATE_DORMANT &&
1538 link->status != DL_STATE_NONE);
1539 __device_link_del(&link->kref);
1540 }
1541
1542 device_links_write_unlock();
1543}
1544
1545#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1546 DL_FLAG_SYNC_STATE_ONLY)
1547#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1548 DL_FLAG_AUTOPROBE_CONSUMER)
1549#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1550 DL_FLAG_PM_RUNTIME)
1551
1552static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1553static int __init fw_devlink_setup(char *arg)
1554{
1555 if (!arg)
1556 return -EINVAL;
1557
1558 if (strcmp(arg, "off") == 0) {
1559 fw_devlink_flags = 0;
1560 } else if (strcmp(arg, "permissive") == 0) {
1561 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1562 } else if (strcmp(arg, "on") == 0) {
1563 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1564 } else if (strcmp(arg, "rpm") == 0) {
1565 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1566 }
1567 return 0;
1568}
1569early_param("fw_devlink", fw_devlink_setup);
1570
1571static bool fw_devlink_strict;
1572static int __init fw_devlink_strict_setup(char *arg)
1573{
1574 return strtobool(arg, &fw_devlink_strict);
1575}
1576early_param("fw_devlink.strict", fw_devlink_strict_setup);
1577
1578u32 fw_devlink_get_flags(void)
1579{
1580 return fw_devlink_flags;
1581}
1582
1583static bool fw_devlink_is_permissive(void)
1584{
1585 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1586}
1587
1588bool fw_devlink_is_strict(void)
1589{
1590 return fw_devlink_strict && !fw_devlink_is_permissive();
1591}
1592
1593static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1594{
1595 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1596 return;
1597
1598 fwnode_call_int_op(fwnode, add_links);
1599 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1600}
1601
1602static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1603{
1604 struct fwnode_handle *child = NULL;
1605
1606 fw_devlink_parse_fwnode(fwnode);
1607
1608 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1609 fw_devlink_parse_fwtree(child);
1610}
1611
1612static void fw_devlink_relax_link(struct device_link *link)
1613{
1614 if (!(link->flags & DL_FLAG_INFERRED))
1615 return;
1616
1617 if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE))
1618 return;
1619
1620 pm_runtime_drop_link(link);
1621 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1622 dev_dbg(link->consumer, "Relaxing link with %s\n",
1623 dev_name(link->supplier));
1624}
1625
1626static int fw_devlink_no_driver(struct device *dev, void *data)
1627{
1628 struct device_link *link = to_devlink(dev);
1629
1630 if (!link->supplier->can_match)
1631 fw_devlink_relax_link(link);
1632
1633 return 0;
1634}
1635
1636void fw_devlink_drivers_done(void)
1637{
1638 fw_devlink_drv_reg_done = true;
1639 device_links_write_lock();
1640 class_for_each_device(&devlink_class, NULL, NULL,
1641 fw_devlink_no_driver);
1642 device_links_write_unlock();
1643}
1644
1645static void fw_devlink_unblock_consumers(struct device *dev)
1646{
1647 struct device_link *link;
1648
1649 if (!fw_devlink_flags || fw_devlink_is_permissive())
1650 return;
1651
1652 device_links_write_lock();
1653 list_for_each_entry(link, &dev->links.consumers, s_node)
1654 fw_devlink_relax_link(link);
1655 device_links_write_unlock();
1656}
1657
1658/**
1659 * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links
1660 * @con: Device to check dependencies for.
1661 * @sup: Device to check against.
1662 *
1663 * Check if @sup depends on @con or any device dependent on it (its child or
1664 * its consumer etc). When such a cyclic dependency is found, convert all
1665 * device links created solely by fw_devlink into SYNC_STATE_ONLY device links.
1666 * This is the equivalent of doing fw_devlink=permissive just between the
1667 * devices in the cycle. We need to do this because, at this point, fw_devlink
1668 * can't tell which of these dependencies is not a real dependency.
1669 *
1670 * Return 1 if a cycle is found. Otherwise, return 0.
1671 */
1672static int fw_devlink_relax_cycle(struct device *con, void *sup)
1673{
1674 struct device_link *link;
1675 int ret;
1676
1677 if (con == sup)
1678 return 1;
1679
1680 ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
1681 if (ret)
1682 return ret;
1683
1684 list_for_each_entry(link, &con->links.consumers, s_node) {
1685 if ((link->flags & ~DL_FLAG_INFERRED) ==
1686 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
1687 continue;
1688
1689 if (!fw_devlink_relax_cycle(link->consumer, sup))
1690 continue;
1691
1692 ret = 1;
1693
1694 fw_devlink_relax_link(link);
1695 }
1696 return ret;
1697}
1698
1699/**
1700 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
1701 * @con: consumer device for the device link
1702 * @sup_handle: fwnode handle of supplier
1703 * @flags: devlink flags
1704 *
1705 * This function will try to create a device link between the consumer device
1706 * @con and the supplier device represented by @sup_handle.
1707 *
1708 * The supplier has to be provided as a fwnode because incorrect cycles in
1709 * fwnode links can sometimes cause the supplier device to never be created.
1710 * This function detects such cases and returns an error if it cannot create a
1711 * device link from the consumer to a missing supplier.
1712 *
1713 * Returns,
1714 * 0 on successfully creating a device link
1715 * -EINVAL if the device link cannot be created as expected
1716 * -EAGAIN if the device link cannot be created right now, but it may be
1717 * possible to do that in the future
1718 */
1719static int fw_devlink_create_devlink(struct device *con,
1720 struct fwnode_handle *sup_handle, u32 flags)
1721{
1722 struct device *sup_dev;
1723 int ret = 0;
1724
1725 /*
1726 * In some cases, a device P might also be a supplier to its child node
1727 * C. However, this would defer the probe of C until the probe of P
1728 * completes successfully. This is perfectly fine in the device driver
1729 * model. device_add() doesn't guarantee probe completion of the device
1730 * by the time it returns.
1731 *
1732 * However, there are a few drivers that assume C will finish probing
1733 * as soon as it's added and before P finishes probing. So, we provide
1734 * a flag to let fw_devlink know not to delay the probe of C until the
1735 * probe of P completes successfully.
1736 *
1737 * When such a flag is set, we can't create device links where P is the
1738 * supplier of C as that would delay the probe of C.
1739 */
1740 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
1741 fwnode_is_ancestor_of(sup_handle, con->fwnode))
1742 return -EINVAL;
1743
1744 sup_dev = get_dev_from_fwnode(sup_handle);
1745 if (sup_dev) {
1746 /*
1747 * If it's one of those drivers that don't actually bind to
1748 * their device using driver core, then don't wait on this
1749 * supplier device indefinitely.
1750 */
1751 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
1752 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
1753 ret = -EINVAL;
1754 goto out;
1755 }
1756
1757 /*
1758 * If this fails, it is due to cycles in device links. Just
1759 * give up on this link and treat it as invalid.
1760 */
1761 if (!device_link_add(con, sup_dev, flags) &&
1762 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
1763 dev_info(con, "Fixing up cyclic dependency with %s\n",
1764 dev_name(sup_dev));
1765 device_links_write_lock();
1766 fw_devlink_relax_cycle(con, sup_dev);
1767 device_links_write_unlock();
1768 device_link_add(con, sup_dev,
1769 FW_DEVLINK_FLAGS_PERMISSIVE);
1770 ret = -EINVAL;
1771 }
1772
1773 goto out;
1774 }
1775
1776 /* Supplier that's already initialized without a struct device. */
1777 if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
1778 return -EINVAL;
1779
1780 /*
1781 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
1782 * cycles. So cycle detection isn't necessary and shouldn't be
1783 * done.
1784 */
1785 if (flags & DL_FLAG_SYNC_STATE_ONLY)
1786 return -EAGAIN;
1787
1788 /*
1789 * If we can't find the supplier device from its fwnode, it might be
1790 * due to a cyclic dependency between fwnodes. Some of these cycles can
1791 * be broken by applying logic. Check for these types of cycles and
1792 * break them so that devices in the cycle probe properly.
1793 *
1794 * If the supplier's parent is dependent on the consumer, then the
1795 * consumer and supplier have a cyclic dependency. Since fw_devlink
1796 * can't tell which of the inferred dependencies are incorrect, don't
1797 * enforce probe ordering between any of the devices in this cyclic
1798 * dependency. Do this by relaxing all the fw_devlink device links in
1799 * this cycle and by treating the fwnode link between the consumer and
1800 * the supplier as an invalid dependency.
1801 */
1802 sup_dev = fwnode_get_next_parent_dev(sup_handle);
1803 if (sup_dev && device_is_dependent(con, sup_dev)) {
1804 dev_info(con, "Fixing up cyclic dependency with %pfwP (%s)\n",
1805 sup_handle, dev_name(sup_dev));
1806 device_links_write_lock();
1807 fw_devlink_relax_cycle(con, sup_dev);
1808 device_links_write_unlock();
1809 ret = -EINVAL;
1810 } else {
1811 /*
1812 * Can't check for cycles or no cycles. So let's try
1813 * again later.
1814 */
1815 ret = -EAGAIN;
1816 }
1817
1818out:
1819 put_device(sup_dev);
1820 return ret;
1821}
1822
1823/**
1824 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
1825 * @dev: Device that needs to be linked to its consumers
1826 *
1827 * This function looks at all the consumer fwnodes of @dev and creates device
1828 * links between the consumer device and @dev (supplier).
1829 *
1830 * If the consumer device has not been added yet, then this function creates a
1831 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
1832 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
1833 * sync_state() callback before the real consumer device gets to be added and
1834 * then probed.
1835 *
1836 * Once device links are created from the real consumer to @dev (supplier), the
1837 * fwnode links are deleted.
1838 */
1839static void __fw_devlink_link_to_consumers(struct device *dev)
1840{
1841 struct fwnode_handle *fwnode = dev->fwnode;
1842 struct fwnode_link *link, *tmp;
1843
1844 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
1845 u32 dl_flags = fw_devlink_get_flags();
1846 struct device *con_dev;
1847 bool own_link = true;
1848 int ret;
1849
1850 con_dev = get_dev_from_fwnode(link->consumer);
1851 /*
1852 * If consumer device is not available yet, make a "proxy"
1853 * SYNC_STATE_ONLY link from the consumer's parent device to
1854 * the supplier device. This is necessary to make sure the
1855 * supplier doesn't get a sync_state() callback before the real
1856 * consumer can create a device link to the supplier.
1857 *
1858 * This proxy link step is needed to handle the case where the
1859 * consumer's parent device is added before the supplier.
1860 */
1861 if (!con_dev) {
1862 con_dev = fwnode_get_next_parent_dev(link->consumer);
1863 /*
1864 * However, if the consumer's parent device is also the
1865 * parent of the supplier, don't create a
1866 * consumer-supplier link from the parent to its child
1867 * device. Such a dependency is impossible.
1868 */
1869 if (con_dev &&
1870 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
1871 put_device(con_dev);
1872 con_dev = NULL;
1873 } else {
1874 own_link = false;
1875 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1876 }
1877 }
1878
1879 if (!con_dev)
1880 continue;
1881
1882 ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags);
1883 put_device(con_dev);
1884 if (!own_link || ret == -EAGAIN)
1885 continue;
1886
1887 list_del(&link->s_hook);
1888 list_del(&link->c_hook);
1889 kfree(link);
1890 }
1891}
1892
1893/**
1894 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
1895 * @dev: The consumer device that needs to be linked to its suppliers
1896 * @fwnode: Root of the fwnode tree that is used to create device links
1897 *
1898 * This function looks at all the supplier fwnodes of fwnode tree rooted at
1899 * @fwnode and creates device links between @dev (consumer) and all the
1900 * supplier devices of the entire fwnode tree at @fwnode.
1901 *
1902 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
1903 * and the real suppliers of @dev. Once these device links are created, the
1904 * fwnode links are deleted. When such device links are successfully created,
1905 * this function is called recursively on those supplier devices. This is
1906 * needed to detect and break some invalid cycles in fwnode links. See
1907 * fw_devlink_create_devlink() for more details.
1908 *
1909 * In addition, it also looks at all the suppliers of the entire fwnode tree
1910 * because some of the child devices of @dev that have not been added yet
1911 * (because @dev hasn't probed) might already have their suppliers added to
1912 * driver core. So, this function creates SYNC_STATE_ONLY device links between
1913 * @dev (consumer) and these suppliers to make sure they don't execute their
1914 * sync_state() callbacks before these child devices have a chance to create
1915 * their device links. The fwnode links that correspond to the child devices
1916 * aren't delete because they are needed later to create the device links
1917 * between the real consumer and supplier devices.
1918 */
1919static void __fw_devlink_link_to_suppliers(struct device *dev,
1920 struct fwnode_handle *fwnode)
1921{
1922 bool own_link = (dev->fwnode == fwnode);
1923 struct fwnode_link *link, *tmp;
1924 struct fwnode_handle *child = NULL;
1925 u32 dl_flags;
1926
1927 if (own_link)
1928 dl_flags = fw_devlink_get_flags();
1929 else
1930 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1931
1932 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
1933 int ret;
1934 struct device *sup_dev;
1935 struct fwnode_handle *sup = link->supplier;
1936
1937 ret = fw_devlink_create_devlink(dev, sup, dl_flags);
1938 if (!own_link || ret == -EAGAIN)
1939 continue;
1940
1941 list_del(&link->s_hook);
1942 list_del(&link->c_hook);
1943 kfree(link);
1944
1945 /* If no device link was created, nothing more to do. */
1946 if (ret)
1947 continue;
1948
1949 /*
1950 * If a device link was successfully created to a supplier, we
1951 * now need to try and link the supplier to all its suppliers.
1952 *
1953 * This is needed to detect and delete false dependencies in
1954 * fwnode links that haven't been converted to a device link
1955 * yet. See comments in fw_devlink_create_devlink() for more
1956 * details on the false dependency.
1957 *
1958 * Without deleting these false dependencies, some devices will
1959 * never probe because they'll keep waiting for their false
1960 * dependency fwnode links to be converted to device links.
1961 */
1962 sup_dev = get_dev_from_fwnode(sup);
1963 __fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode);
1964 put_device(sup_dev);
1965 }
1966
1967 /*
1968 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
1969 * all the descendants. This proxy link step is needed to handle the
1970 * case where the supplier is added before the consumer's parent device
1971 * (@dev).
1972 */
1973 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1974 __fw_devlink_link_to_suppliers(dev, child);
1975}
1976
1977static void fw_devlink_link_device(struct device *dev)
1978{
1979 struct fwnode_handle *fwnode = dev->fwnode;
1980
1981 if (!fw_devlink_flags)
1982 return;
1983
1984 fw_devlink_parse_fwtree(fwnode);
1985
1986 mutex_lock(&fwnode_link_lock);
1987 __fw_devlink_link_to_consumers(dev);
1988 __fw_devlink_link_to_suppliers(dev, fwnode);
1989 mutex_unlock(&fwnode_link_lock);
1990}
1991
1992/* Device links support end. */
1993
1994int (*platform_notify)(struct device *dev) = NULL;
1995int (*platform_notify_remove)(struct device *dev) = NULL;
1996static struct kobject *dev_kobj;
1997struct kobject *sysfs_dev_char_kobj;
1998struct kobject *sysfs_dev_block_kobj;
1999
2000static DEFINE_MUTEX(device_hotplug_lock);
2001
2002void lock_device_hotplug(void)
2003{
2004 mutex_lock(&device_hotplug_lock);
2005}
2006
2007void unlock_device_hotplug(void)
2008{
2009 mutex_unlock(&device_hotplug_lock);
2010}
2011
2012int lock_device_hotplug_sysfs(void)
2013{
2014 if (mutex_trylock(&device_hotplug_lock))
2015 return 0;
2016
2017 /* Avoid busy looping (5 ms of sleep should do). */
2018 msleep(5);
2019 return restart_syscall();
2020}
2021
2022#ifdef CONFIG_BLOCK
2023static inline int device_is_not_partition(struct device *dev)
2024{
2025 return !(dev->type == &part_type);
2026}
2027#else
2028static inline int device_is_not_partition(struct device *dev)
2029{
2030 return 1;
2031}
2032#endif
2033
2034static int
2035device_platform_notify(struct device *dev, enum kobject_action action)
2036{
2037 int ret;
2038
2039 ret = acpi_platform_notify(dev, action);
2040 if (ret)
2041 return ret;
2042
2043 ret = software_node_notify(dev, action);
2044 if (ret)
2045 return ret;
2046
2047 if (platform_notify && action == KOBJ_ADD)
2048 platform_notify(dev);
2049 else if (platform_notify_remove && action == KOBJ_REMOVE)
2050 platform_notify_remove(dev);
2051 return 0;
2052}
2053
2054/**
2055 * dev_driver_string - Return a device's driver name, if at all possible
2056 * @dev: struct device to get the name of
2057 *
2058 * Will return the device's driver's name if it is bound to a device. If
2059 * the device is not bound to a driver, it will return the name of the bus
2060 * it is attached to. If it is not attached to a bus either, an empty
2061 * string will be returned.
2062 */
2063const char *dev_driver_string(const struct device *dev)
2064{
2065 struct device_driver *drv;
2066
2067 /* dev->driver can change to NULL underneath us because of unbinding,
2068 * so be careful about accessing it. dev->bus and dev->class should
2069 * never change once they are set, so they don't need special care.
2070 */
2071 drv = READ_ONCE(dev->driver);
2072 return drv ? drv->name : dev_bus_name(dev);
2073}
2074EXPORT_SYMBOL(dev_driver_string);
2075
2076#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2077
2078static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2079 char *buf)
2080{
2081 struct device_attribute *dev_attr = to_dev_attr(attr);
2082 struct device *dev = kobj_to_dev(kobj);
2083 ssize_t ret = -EIO;
2084
2085 if (dev_attr->show)
2086 ret = dev_attr->show(dev, dev_attr, buf);
2087 if (ret >= (ssize_t)PAGE_SIZE) {
2088 printk("dev_attr_show: %pS returned bad count\n",
2089 dev_attr->show);
2090 }
2091 return ret;
2092}
2093
2094static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2095 const char *buf, size_t count)
2096{
2097 struct device_attribute *dev_attr = to_dev_attr(attr);
2098 struct device *dev = kobj_to_dev(kobj);
2099 ssize_t ret = -EIO;
2100
2101 if (dev_attr->store)
2102 ret = dev_attr->store(dev, dev_attr, buf, count);
2103 return ret;
2104}
2105
2106static const struct sysfs_ops dev_sysfs_ops = {
2107 .show = dev_attr_show,
2108 .store = dev_attr_store,
2109};
2110
2111#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2112
2113ssize_t device_store_ulong(struct device *dev,
2114 struct device_attribute *attr,
2115 const char *buf, size_t size)
2116{
2117 struct dev_ext_attribute *ea = to_ext_attr(attr);
2118 int ret;
2119 unsigned long new;
2120
2121 ret = kstrtoul(buf, 0, &new);
2122 if (ret)
2123 return ret;
2124 *(unsigned long *)(ea->var) = new;
2125 /* Always return full write size even if we didn't consume all */
2126 return size;
2127}
2128EXPORT_SYMBOL_GPL(device_store_ulong);
2129
2130ssize_t device_show_ulong(struct device *dev,
2131 struct device_attribute *attr,
2132 char *buf)
2133{
2134 struct dev_ext_attribute *ea = to_ext_attr(attr);
2135 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2136}
2137EXPORT_SYMBOL_GPL(device_show_ulong);
2138
2139ssize_t device_store_int(struct device *dev,
2140 struct device_attribute *attr,
2141 const char *buf, size_t size)
2142{
2143 struct dev_ext_attribute *ea = to_ext_attr(attr);
2144 int ret;
2145 long new;
2146
2147 ret = kstrtol(buf, 0, &new);
2148 if (ret)
2149 return ret;
2150
2151 if (new > INT_MAX || new < INT_MIN)
2152 return -EINVAL;
2153 *(int *)(ea->var) = new;
2154 /* Always return full write size even if we didn't consume all */
2155 return size;
2156}
2157EXPORT_SYMBOL_GPL(device_store_int);
2158
2159ssize_t device_show_int(struct device *dev,
2160 struct device_attribute *attr,
2161 char *buf)
2162{
2163 struct dev_ext_attribute *ea = to_ext_attr(attr);
2164
2165 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2166}
2167EXPORT_SYMBOL_GPL(device_show_int);
2168
2169ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2170 const char *buf, size_t size)
2171{
2172 struct dev_ext_attribute *ea = to_ext_attr(attr);
2173
2174 if (strtobool(buf, ea->var) < 0)
2175 return -EINVAL;
2176
2177 return size;
2178}
2179EXPORT_SYMBOL_GPL(device_store_bool);
2180
2181ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2182 char *buf)
2183{
2184 struct dev_ext_attribute *ea = to_ext_attr(attr);
2185
2186 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2187}
2188EXPORT_SYMBOL_GPL(device_show_bool);
2189
2190/**
2191 * device_release - free device structure.
2192 * @kobj: device's kobject.
2193 *
2194 * This is called once the reference count for the object
2195 * reaches 0. We forward the call to the device's release
2196 * method, which should handle actually freeing the structure.
2197 */
2198static void device_release(struct kobject *kobj)
2199{
2200 struct device *dev = kobj_to_dev(kobj);
2201 struct device_private *p = dev->p;
2202
2203 /*
2204 * Some platform devices are driven without driver attached
2205 * and managed resources may have been acquired. Make sure
2206 * all resources are released.
2207 *
2208 * Drivers still can add resources into device after device
2209 * is deleted but alive, so release devres here to avoid
2210 * possible memory leak.
2211 */
2212 devres_release_all(dev);
2213
2214 kfree(dev->dma_range_map);
2215
2216 if (dev->release)
2217 dev->release(dev);
2218 else if (dev->type && dev->type->release)
2219 dev->type->release(dev);
2220 else if (dev->class && dev->class->dev_release)
2221 dev->class->dev_release(dev);
2222 else
2223 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",
2224 dev_name(dev));
2225 kfree(p);
2226}
2227
2228static const void *device_namespace(struct kobject *kobj)
2229{
2230 struct device *dev = kobj_to_dev(kobj);
2231 const void *ns = NULL;
2232
2233 if (dev->class && dev->class->ns_type)
2234 ns = dev->class->namespace(dev);
2235
2236 return ns;
2237}
2238
2239static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2240{
2241 struct device *dev = kobj_to_dev(kobj);
2242
2243 if (dev->class && dev->class->get_ownership)
2244 dev->class->get_ownership(dev, uid, gid);
2245}
2246
2247static struct kobj_type device_ktype = {
2248 .release = device_release,
2249 .sysfs_ops = &dev_sysfs_ops,
2250 .namespace = device_namespace,
2251 .get_ownership = device_get_ownership,
2252};
2253
2254
2255static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
2256{
2257 struct kobj_type *ktype = get_ktype(kobj);
2258
2259 if (ktype == &device_ktype) {
2260 struct device *dev = kobj_to_dev(kobj);
2261 if (dev->bus)
2262 return 1;
2263 if (dev->class)
2264 return 1;
2265 }
2266 return 0;
2267}
2268
2269static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
2270{
2271 struct device *dev = kobj_to_dev(kobj);
2272
2273 if (dev->bus)
2274 return dev->bus->name;
2275 if (dev->class)
2276 return dev->class->name;
2277 return NULL;
2278}
2279
2280static int dev_uevent(struct kset *kset, struct kobject *kobj,
2281 struct kobj_uevent_env *env)
2282{
2283 struct device *dev = kobj_to_dev(kobj);
2284 int retval = 0;
2285
2286 /* add device node properties if present */
2287 if (MAJOR(dev->devt)) {
2288 const char *tmp;
2289 const char *name;
2290 umode_t mode = 0;
2291 kuid_t uid = GLOBAL_ROOT_UID;
2292 kgid_t gid = GLOBAL_ROOT_GID;
2293
2294 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2295 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2296 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2297 if (name) {
2298 add_uevent_var(env, "DEVNAME=%s", name);
2299 if (mode)
2300 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2301 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2302 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2303 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2304 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2305 kfree(tmp);
2306 }
2307 }
2308
2309 if (dev->type && dev->type->name)
2310 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2311
2312 if (dev->driver)
2313 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2314
2315 /* Add common DT information about the device */
2316 of_device_uevent(dev, env);
2317
2318 /* have the bus specific function add its stuff */
2319 if (dev->bus && dev->bus->uevent) {
2320 retval = dev->bus->uevent(dev, env);
2321 if (retval)
2322 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2323 dev_name(dev), __func__, retval);
2324 }
2325
2326 /* have the class specific function add its stuff */
2327 if (dev->class && dev->class->dev_uevent) {
2328 retval = dev->class->dev_uevent(dev, env);
2329 if (retval)
2330 pr_debug("device: '%s': %s: class uevent() "
2331 "returned %d\n", dev_name(dev),
2332 __func__, retval);
2333 }
2334
2335 /* have the device type specific function add its stuff */
2336 if (dev->type && dev->type->uevent) {
2337 retval = dev->type->uevent(dev, env);
2338 if (retval)
2339 pr_debug("device: '%s': %s: dev_type uevent() "
2340 "returned %d\n", dev_name(dev),
2341 __func__, retval);
2342 }
2343
2344 return retval;
2345}
2346
2347static const struct kset_uevent_ops device_uevent_ops = {
2348 .filter = dev_uevent_filter,
2349 .name = dev_uevent_name,
2350 .uevent = dev_uevent,
2351};
2352
2353static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2354 char *buf)
2355{
2356 struct kobject *top_kobj;
2357 struct kset *kset;
2358 struct kobj_uevent_env *env = NULL;
2359 int i;
2360 int len = 0;
2361 int retval;
2362
2363 /* search the kset, the device belongs to */
2364 top_kobj = &dev->kobj;
2365 while (!top_kobj->kset && top_kobj->parent)
2366 top_kobj = top_kobj->parent;
2367 if (!top_kobj->kset)
2368 goto out;
2369
2370 kset = top_kobj->kset;
2371 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2372 goto out;
2373
2374 /* respect filter */
2375 if (kset->uevent_ops && kset->uevent_ops->filter)
2376 if (!kset->uevent_ops->filter(kset, &dev->kobj))
2377 goto out;
2378
2379 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2380 if (!env)
2381 return -ENOMEM;
2382
2383 /* let the kset specific function add its keys */
2384 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
2385 if (retval)
2386 goto out;
2387
2388 /* copy keys to file */
2389 for (i = 0; i < env->envp_idx; i++)
2390 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2391out:
2392 kfree(env);
2393 return len;
2394}
2395
2396static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2397 const char *buf, size_t count)
2398{
2399 int rc;
2400
2401 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2402
2403 if (rc) {
2404 dev_err(dev, "uevent: failed to send synthetic uevent\n");
2405 return rc;
2406 }
2407
2408 return count;
2409}
2410static DEVICE_ATTR_RW(uevent);
2411
2412static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2413 char *buf)
2414{
2415 bool val;
2416
2417 device_lock(dev);
2418 val = !dev->offline;
2419 device_unlock(dev);
2420 return sysfs_emit(buf, "%u\n", val);
2421}
2422
2423static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2424 const char *buf, size_t count)
2425{
2426 bool val;
2427 int ret;
2428
2429 ret = strtobool(buf, &val);
2430 if (ret < 0)
2431 return ret;
2432
2433 ret = lock_device_hotplug_sysfs();
2434 if (ret)
2435 return ret;
2436
2437 ret = val ? device_online(dev) : device_offline(dev);
2438 unlock_device_hotplug();
2439 return ret < 0 ? ret : count;
2440}
2441static DEVICE_ATTR_RW(online);
2442
2443static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2444 char *buf)
2445{
2446 const char *loc;
2447
2448 switch (dev->removable) {
2449 case DEVICE_REMOVABLE:
2450 loc = "removable";
2451 break;
2452 case DEVICE_FIXED:
2453 loc = "fixed";
2454 break;
2455 default:
2456 loc = "unknown";
2457 }
2458 return sysfs_emit(buf, "%s\n", loc);
2459}
2460static DEVICE_ATTR_RO(removable);
2461
2462int device_add_groups(struct device *dev, const struct attribute_group **groups)
2463{
2464 return sysfs_create_groups(&dev->kobj, groups);
2465}
2466EXPORT_SYMBOL_GPL(device_add_groups);
2467
2468void device_remove_groups(struct device *dev,
2469 const struct attribute_group **groups)
2470{
2471 sysfs_remove_groups(&dev->kobj, groups);
2472}
2473EXPORT_SYMBOL_GPL(device_remove_groups);
2474
2475union device_attr_group_devres {
2476 const struct attribute_group *group;
2477 const struct attribute_group **groups;
2478};
2479
2480static int devm_attr_group_match(struct device *dev, void *res, void *data)
2481{
2482 return ((union device_attr_group_devres *)res)->group == data;
2483}
2484
2485static void devm_attr_group_remove(struct device *dev, void *res)
2486{
2487 union device_attr_group_devres *devres = res;
2488 const struct attribute_group *group = devres->group;
2489
2490 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2491 sysfs_remove_group(&dev->kobj, group);
2492}
2493
2494static void devm_attr_groups_remove(struct device *dev, void *res)
2495{
2496 union device_attr_group_devres *devres = res;
2497 const struct attribute_group **groups = devres->groups;
2498
2499 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2500 sysfs_remove_groups(&dev->kobj, groups);
2501}
2502
2503/**
2504 * devm_device_add_group - given a device, create a managed attribute group
2505 * @dev: The device to create the group for
2506 * @grp: The attribute group to create
2507 *
2508 * This function creates a group for the first time. It will explicitly
2509 * warn and error if any of the attribute files being created already exist.
2510 *
2511 * Returns 0 on success or error code on failure.
2512 */
2513int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2514{
2515 union device_attr_group_devres *devres;
2516 int error;
2517
2518 devres = devres_alloc(devm_attr_group_remove,
2519 sizeof(*devres), GFP_KERNEL);
2520 if (!devres)
2521 return -ENOMEM;
2522
2523 error = sysfs_create_group(&dev->kobj, grp);
2524 if (error) {
2525 devres_free(devres);
2526 return error;
2527 }
2528
2529 devres->group = grp;
2530 devres_add(dev, devres);
2531 return 0;
2532}
2533EXPORT_SYMBOL_GPL(devm_device_add_group);
2534
2535/**
2536 * devm_device_remove_group: remove a managed group from a device
2537 * @dev: device to remove the group from
2538 * @grp: group to remove
2539 *
2540 * This function removes a group of attributes from a device. The attributes
2541 * previously have to have been created for this group, otherwise it will fail.
2542 */
2543void devm_device_remove_group(struct device *dev,
2544 const struct attribute_group *grp)
2545{
2546 WARN_ON(devres_release(dev, devm_attr_group_remove,
2547 devm_attr_group_match,
2548 /* cast away const */ (void *)grp));
2549}
2550EXPORT_SYMBOL_GPL(devm_device_remove_group);
2551
2552/**
2553 * devm_device_add_groups - create a bunch of managed attribute groups
2554 * @dev: The device to create the group for
2555 * @groups: The attribute groups to create, NULL terminated
2556 *
2557 * This function creates a bunch of managed attribute groups. If an error
2558 * occurs when creating a group, all previously created groups will be
2559 * removed, unwinding everything back to the original state when this
2560 * function was called. It will explicitly warn and error if any of the
2561 * attribute files being created already exist.
2562 *
2563 * Returns 0 on success or error code from sysfs_create_group on failure.
2564 */
2565int devm_device_add_groups(struct device *dev,
2566 const struct attribute_group **groups)
2567{
2568 union device_attr_group_devres *devres;
2569 int error;
2570
2571 devres = devres_alloc(devm_attr_groups_remove,
2572 sizeof(*devres), GFP_KERNEL);
2573 if (!devres)
2574 return -ENOMEM;
2575
2576 error = sysfs_create_groups(&dev->kobj, groups);
2577 if (error) {
2578 devres_free(devres);
2579 return error;
2580 }
2581
2582 devres->groups = groups;
2583 devres_add(dev, devres);
2584 return 0;
2585}
2586EXPORT_SYMBOL_GPL(devm_device_add_groups);
2587
2588/**
2589 * devm_device_remove_groups - remove a list of managed groups
2590 *
2591 * @dev: The device for the groups to be removed from
2592 * @groups: NULL terminated list of groups to be removed
2593 *
2594 * If groups is not NULL, remove the specified groups from the device.
2595 */
2596void devm_device_remove_groups(struct device *dev,
2597 const struct attribute_group **groups)
2598{
2599 WARN_ON(devres_release(dev, devm_attr_groups_remove,
2600 devm_attr_group_match,
2601 /* cast away const */ (void *)groups));
2602}
2603EXPORT_SYMBOL_GPL(devm_device_remove_groups);
2604
2605static int device_add_attrs(struct device *dev)
2606{
2607 struct class *class = dev->class;
2608 const struct device_type *type = dev->type;
2609 int error;
2610
2611 if (class) {
2612 error = device_add_groups(dev, class->dev_groups);
2613 if (error)
2614 return error;
2615 }
2616
2617 if (type) {
2618 error = device_add_groups(dev, type->groups);
2619 if (error)
2620 goto err_remove_class_groups;
2621 }
2622
2623 error = device_add_groups(dev, dev->groups);
2624 if (error)
2625 goto err_remove_type_groups;
2626
2627 if (device_supports_offline(dev) && !dev->offline_disabled) {
2628 error = device_create_file(dev, &dev_attr_online);
2629 if (error)
2630 goto err_remove_dev_groups;
2631 }
2632
2633 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2634 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2635 if (error)
2636 goto err_remove_dev_online;
2637 }
2638
2639 if (dev_removable_is_valid(dev)) {
2640 error = device_create_file(dev, &dev_attr_removable);
2641 if (error)
2642 goto err_remove_dev_waiting_for_supplier;
2643 }
2644
2645 return 0;
2646
2647 err_remove_dev_waiting_for_supplier:
2648 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2649 err_remove_dev_online:
2650 device_remove_file(dev, &dev_attr_online);
2651 err_remove_dev_groups:
2652 device_remove_groups(dev, dev->groups);
2653 err_remove_type_groups:
2654 if (type)
2655 device_remove_groups(dev, type->groups);
2656 err_remove_class_groups:
2657 if (class)
2658 device_remove_groups(dev, class->dev_groups);
2659
2660 return error;
2661}
2662
2663static void device_remove_attrs(struct device *dev)
2664{
2665 struct class *class = dev->class;
2666 const struct device_type *type = dev->type;
2667
2668 device_remove_file(dev, &dev_attr_removable);
2669 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2670 device_remove_file(dev, &dev_attr_online);
2671 device_remove_groups(dev, dev->groups);
2672
2673 if (type)
2674 device_remove_groups(dev, type->groups);
2675
2676 if (class)
2677 device_remove_groups(dev, class->dev_groups);
2678}
2679
2680static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2681 char *buf)
2682{
2683 return print_dev_t(buf, dev->devt);
2684}
2685static DEVICE_ATTR_RO(dev);
2686
2687/* /sys/devices/ */
2688struct kset *devices_kset;
2689
2690/**
2691 * devices_kset_move_before - Move device in the devices_kset's list.
2692 * @deva: Device to move.
2693 * @devb: Device @deva should come before.
2694 */
2695static void devices_kset_move_before(struct device *deva, struct device *devb)
2696{
2697 if (!devices_kset)
2698 return;
2699 pr_debug("devices_kset: Moving %s before %s\n",
2700 dev_name(deva), dev_name(devb));
2701 spin_lock(&devices_kset->list_lock);
2702 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2703 spin_unlock(&devices_kset->list_lock);
2704}
2705
2706/**
2707 * devices_kset_move_after - Move device in the devices_kset's list.
2708 * @deva: Device to move
2709 * @devb: Device @deva should come after.
2710 */
2711static void devices_kset_move_after(struct device *deva, struct device *devb)
2712{
2713 if (!devices_kset)
2714 return;
2715 pr_debug("devices_kset: Moving %s after %s\n",
2716 dev_name(deva), dev_name(devb));
2717 spin_lock(&devices_kset->list_lock);
2718 list_move(&deva->kobj.entry, &devb->kobj.entry);
2719 spin_unlock(&devices_kset->list_lock);
2720}
2721
2722/**
2723 * devices_kset_move_last - move the device to the end of devices_kset's list.
2724 * @dev: device to move
2725 */
2726void devices_kset_move_last(struct device *dev)
2727{
2728 if (!devices_kset)
2729 return;
2730 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2731 spin_lock(&devices_kset->list_lock);
2732 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2733 spin_unlock(&devices_kset->list_lock);
2734}
2735
2736/**
2737 * device_create_file - create sysfs attribute file for device.
2738 * @dev: device.
2739 * @attr: device attribute descriptor.
2740 */
2741int device_create_file(struct device *dev,
2742 const struct device_attribute *attr)
2743{
2744 int error = 0;
2745
2746 if (dev) {
2747 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2748 "Attribute %s: write permission without 'store'\n",
2749 attr->attr.name);
2750 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2751 "Attribute %s: read permission without 'show'\n",
2752 attr->attr.name);
2753 error = sysfs_create_file(&dev->kobj, &attr->attr);
2754 }
2755
2756 return error;
2757}
2758EXPORT_SYMBOL_GPL(device_create_file);
2759
2760/**
2761 * device_remove_file - remove sysfs attribute file.
2762 * @dev: device.
2763 * @attr: device attribute descriptor.
2764 */
2765void device_remove_file(struct device *dev,
2766 const struct device_attribute *attr)
2767{
2768 if (dev)
2769 sysfs_remove_file(&dev->kobj, &attr->attr);
2770}
2771EXPORT_SYMBOL_GPL(device_remove_file);
2772
2773/**
2774 * device_remove_file_self - remove sysfs attribute file from its own method.
2775 * @dev: device.
2776 * @attr: device attribute descriptor.
2777 *
2778 * See kernfs_remove_self() for details.
2779 */
2780bool device_remove_file_self(struct device *dev,
2781 const struct device_attribute *attr)
2782{
2783 if (dev)
2784 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2785 else
2786 return false;
2787}
2788EXPORT_SYMBOL_GPL(device_remove_file_self);
2789
2790/**
2791 * device_create_bin_file - create sysfs binary attribute file for device.
2792 * @dev: device.
2793 * @attr: device binary attribute descriptor.
2794 */
2795int device_create_bin_file(struct device *dev,
2796 const struct bin_attribute *attr)
2797{
2798 int error = -EINVAL;
2799 if (dev)
2800 error = sysfs_create_bin_file(&dev->kobj, attr);
2801 return error;
2802}
2803EXPORT_SYMBOL_GPL(device_create_bin_file);
2804
2805/**
2806 * device_remove_bin_file - remove sysfs binary attribute file
2807 * @dev: device.
2808 * @attr: device binary attribute descriptor.
2809 */
2810void device_remove_bin_file(struct device *dev,
2811 const struct bin_attribute *attr)
2812{
2813 if (dev)
2814 sysfs_remove_bin_file(&dev->kobj, attr);
2815}
2816EXPORT_SYMBOL_GPL(device_remove_bin_file);
2817
2818static void klist_children_get(struct klist_node *n)
2819{
2820 struct device_private *p = to_device_private_parent(n);
2821 struct device *dev = p->device;
2822
2823 get_device(dev);
2824}
2825
2826static void klist_children_put(struct klist_node *n)
2827{
2828 struct device_private *p = to_device_private_parent(n);
2829 struct device *dev = p->device;
2830
2831 put_device(dev);
2832}
2833
2834/**
2835 * device_initialize - init device structure.
2836 * @dev: device.
2837 *
2838 * This prepares the device for use by other layers by initializing
2839 * its fields.
2840 * It is the first half of device_register(), if called by
2841 * that function, though it can also be called separately, so one
2842 * may use @dev's fields. In particular, get_device()/put_device()
2843 * may be used for reference counting of @dev after calling this
2844 * function.
2845 *
2846 * All fields in @dev must be initialized by the caller to 0, except
2847 * for those explicitly set to some other value. The simplest
2848 * approach is to use kzalloc() to allocate the structure containing
2849 * @dev.
2850 *
2851 * NOTE: Use put_device() to give up your reference instead of freeing
2852 * @dev directly once you have called this function.
2853 */
2854void device_initialize(struct device *dev)
2855{
2856 dev->kobj.kset = devices_kset;
2857 kobject_init(&dev->kobj, &device_ktype);
2858 INIT_LIST_HEAD(&dev->dma_pools);
2859 mutex_init(&dev->mutex);
2860#ifdef CONFIG_PROVE_LOCKING
2861 mutex_init(&dev->lockdep_mutex);
2862#endif
2863 lockdep_set_novalidate_class(&dev->mutex);
2864 spin_lock_init(&dev->devres_lock);
2865 INIT_LIST_HEAD(&dev->devres_head);
2866 device_pm_init(dev);
2867 set_dev_node(dev, -1);
2868#ifdef CONFIG_GENERIC_MSI_IRQ
2869 raw_spin_lock_init(&dev->msi_lock);
2870 INIT_LIST_HEAD(&dev->msi_list);
2871#endif
2872 INIT_LIST_HEAD(&dev->links.consumers);
2873 INIT_LIST_HEAD(&dev->links.suppliers);
2874 INIT_LIST_HEAD(&dev->links.defer_sync);
2875 dev->links.status = DL_DEV_NO_DRIVER;
2876#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
2877 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
2878 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
2879 dev->dma_coherent = dma_default_coherent;
2880#endif
2881}
2882EXPORT_SYMBOL_GPL(device_initialize);
2883
2884struct kobject *virtual_device_parent(struct device *dev)
2885{
2886 static struct kobject *virtual_dir = NULL;
2887
2888 if (!virtual_dir)
2889 virtual_dir = kobject_create_and_add("virtual",
2890 &devices_kset->kobj);
2891
2892 return virtual_dir;
2893}
2894
2895struct class_dir {
2896 struct kobject kobj;
2897 struct class *class;
2898};
2899
2900#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2901
2902static void class_dir_release(struct kobject *kobj)
2903{
2904 struct class_dir *dir = to_class_dir(kobj);
2905 kfree(dir);
2906}
2907
2908static const
2909struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
2910{
2911 struct class_dir *dir = to_class_dir(kobj);
2912 return dir->class->ns_type;
2913}
2914
2915static struct kobj_type class_dir_ktype = {
2916 .release = class_dir_release,
2917 .sysfs_ops = &kobj_sysfs_ops,
2918 .child_ns_type = class_dir_child_ns_type
2919};
2920
2921static struct kobject *
2922class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
2923{
2924 struct class_dir *dir;
2925 int retval;
2926
2927 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
2928 if (!dir)
2929 return ERR_PTR(-ENOMEM);
2930
2931 dir->class = class;
2932 kobject_init(&dir->kobj, &class_dir_ktype);
2933
2934 dir->kobj.kset = &class->p->glue_dirs;
2935
2936 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
2937 if (retval < 0) {
2938 kobject_put(&dir->kobj);
2939 return ERR_PTR(retval);
2940 }
2941 return &dir->kobj;
2942}
2943
2944static DEFINE_MUTEX(gdp_mutex);
2945
2946static struct kobject *get_device_parent(struct device *dev,
2947 struct device *parent)
2948{
2949 if (dev->class) {
2950 struct kobject *kobj = NULL;
2951 struct kobject *parent_kobj;
2952 struct kobject *k;
2953
2954#ifdef CONFIG_BLOCK
2955 /* block disks show up in /sys/block */
2956 if (sysfs_deprecated && dev->class == &block_class) {
2957 if (parent && parent->class == &block_class)
2958 return &parent->kobj;
2959 return &block_class.p->subsys.kobj;
2960 }
2961#endif
2962
2963 /*
2964 * If we have no parent, we live in "virtual".
2965 * Class-devices with a non class-device as parent, live
2966 * in a "glue" directory to prevent namespace collisions.
2967 */
2968 if (parent == NULL)
2969 parent_kobj = virtual_device_parent(dev);
2970 else if (parent->class && !dev->class->ns_type)
2971 return &parent->kobj;
2972 else
2973 parent_kobj = &parent->kobj;
2974
2975 mutex_lock(&gdp_mutex);
2976
2977 /* find our class-directory at the parent and reference it */
2978 spin_lock(&dev->class->p->glue_dirs.list_lock);
2979 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
2980 if (k->parent == parent_kobj) {
2981 kobj = kobject_get(k);
2982 break;
2983 }
2984 spin_unlock(&dev->class->p->glue_dirs.list_lock);
2985 if (kobj) {
2986 mutex_unlock(&gdp_mutex);
2987 return kobj;
2988 }
2989
2990 /* or create a new class-directory at the parent device */
2991 k = class_dir_create_and_add(dev->class, parent_kobj);
2992 /* do not emit an uevent for this simple "glue" directory */
2993 mutex_unlock(&gdp_mutex);
2994 return k;
2995 }
2996
2997 /* subsystems can specify a default root directory for their devices */
2998 if (!parent && dev->bus && dev->bus->dev_root)
2999 return &dev->bus->dev_root->kobj;
3000
3001 if (parent)
3002 return &parent->kobj;
3003 return NULL;
3004}
3005
3006static inline bool live_in_glue_dir(struct kobject *kobj,
3007 struct device *dev)
3008{
3009 if (!kobj || !dev->class ||
3010 kobj->kset != &dev->class->p->glue_dirs)
3011 return false;
3012 return true;
3013}
3014
3015static inline struct kobject *get_glue_dir(struct device *dev)
3016{
3017 return dev->kobj.parent;
3018}
3019
3020/*
3021 * make sure cleaning up dir as the last step, we need to make
3022 * sure .release handler of kobject is run with holding the
3023 * global lock
3024 */
3025static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3026{
3027 unsigned int ref;
3028
3029 /* see if we live in a "glue" directory */
3030 if (!live_in_glue_dir(glue_dir, dev))
3031 return;
3032
3033 mutex_lock(&gdp_mutex);
3034 /**
3035 * There is a race condition between removing glue directory
3036 * and adding a new device under the glue directory.
3037 *
3038 * CPU1: CPU2:
3039 *
3040 * device_add()
3041 * get_device_parent()
3042 * class_dir_create_and_add()
3043 * kobject_add_internal()
3044 * create_dir() // create glue_dir
3045 *
3046 * device_add()
3047 * get_device_parent()
3048 * kobject_get() // get glue_dir
3049 *
3050 * device_del()
3051 * cleanup_glue_dir()
3052 * kobject_del(glue_dir)
3053 *
3054 * kobject_add()
3055 * kobject_add_internal()
3056 * create_dir() // in glue_dir
3057 * sysfs_create_dir_ns()
3058 * kernfs_create_dir_ns(sd)
3059 *
3060 * sysfs_remove_dir() // glue_dir->sd=NULL
3061 * sysfs_put() // free glue_dir->sd
3062 *
3063 * // sd is freed
3064 * kernfs_new_node(sd)
3065 * kernfs_get(glue_dir)
3066 * kernfs_add_one()
3067 * kernfs_put()
3068 *
3069 * Before CPU1 remove last child device under glue dir, if CPU2 add
3070 * a new device under glue dir, the glue_dir kobject reference count
3071 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3072 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3073 * and sysfs_put(). This result in glue_dir->sd is freed.
3074 *
3075 * Then the CPU2 will see a stale "empty" but still potentially used
3076 * glue dir around in kernfs_new_node().
3077 *
3078 * In order to avoid this happening, we also should make sure that
3079 * kernfs_node for glue_dir is released in CPU1 only when refcount
3080 * for glue_dir kobj is 1.
3081 */
3082 ref = kref_read(&glue_dir->kref);
3083 if (!kobject_has_children(glue_dir) && !--ref)
3084 kobject_del(glue_dir);
3085 kobject_put(glue_dir);
3086 mutex_unlock(&gdp_mutex);
3087}
3088
3089static int device_add_class_symlinks(struct device *dev)
3090{
3091 struct device_node *of_node = dev_of_node(dev);
3092 int error;
3093
3094 if (of_node) {
3095 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3096 if (error)
3097 dev_warn(dev, "Error %d creating of_node link\n",error);
3098 /* An error here doesn't warrant bringing down the device */
3099 }
3100
3101 if (!dev->class)
3102 return 0;
3103
3104 error = sysfs_create_link(&dev->kobj,
3105 &dev->class->p->subsys.kobj,
3106 "subsystem");
3107 if (error)
3108 goto out_devnode;
3109
3110 if (dev->parent && device_is_not_partition(dev)) {
3111 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3112 "device");
3113 if (error)
3114 goto out_subsys;
3115 }
3116
3117#ifdef CONFIG_BLOCK
3118 /* /sys/block has directories and does not need symlinks */
3119 if (sysfs_deprecated && dev->class == &block_class)
3120 return 0;
3121#endif
3122
3123 /* link in the class directory pointing to the device */
3124 error = sysfs_create_link(&dev->class->p->subsys.kobj,
3125 &dev->kobj, dev_name(dev));
3126 if (error)
3127 goto out_device;
3128
3129 return 0;
3130
3131out_device:
3132 sysfs_remove_link(&dev->kobj, "device");
3133
3134out_subsys:
3135 sysfs_remove_link(&dev->kobj, "subsystem");
3136out_devnode:
3137 sysfs_remove_link(&dev->kobj, "of_node");
3138 return error;
3139}
3140
3141static void device_remove_class_symlinks(struct device *dev)
3142{
3143 if (dev_of_node(dev))
3144 sysfs_remove_link(&dev->kobj, "of_node");
3145
3146 if (!dev->class)
3147 return;
3148
3149 if (dev->parent && device_is_not_partition(dev))
3150 sysfs_remove_link(&dev->kobj, "device");
3151 sysfs_remove_link(&dev->kobj, "subsystem");
3152#ifdef CONFIG_BLOCK
3153 if (sysfs_deprecated && dev->class == &block_class)
3154 return;
3155#endif
3156 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
3157}
3158
3159/**
3160 * dev_set_name - set a device name
3161 * @dev: device
3162 * @fmt: format string for the device's name
3163 */
3164int dev_set_name(struct device *dev, const char *fmt, ...)
3165{
3166 va_list vargs;
3167 int err;
3168
3169 va_start(vargs, fmt);
3170 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3171 va_end(vargs);
3172 return err;
3173}
3174EXPORT_SYMBOL_GPL(dev_set_name);
3175
3176/**
3177 * device_to_dev_kobj - select a /sys/dev/ directory for the device
3178 * @dev: device
3179 *
3180 * By default we select char/ for new entries. Setting class->dev_obj
3181 * to NULL prevents an entry from being created. class->dev_kobj must
3182 * be set (or cleared) before any devices are registered to the class
3183 * otherwise device_create_sys_dev_entry() and
3184 * device_remove_sys_dev_entry() will disagree about the presence of
3185 * the link.
3186 */
3187static struct kobject *device_to_dev_kobj(struct device *dev)
3188{
3189 struct kobject *kobj;
3190
3191 if (dev->class)
3192 kobj = dev->class->dev_kobj;
3193 else
3194 kobj = sysfs_dev_char_kobj;
3195
3196 return kobj;
3197}
3198
3199static int device_create_sys_dev_entry(struct device *dev)
3200{
3201 struct kobject *kobj = device_to_dev_kobj(dev);
3202 int error = 0;
3203 char devt_str[15];
3204
3205 if (kobj) {
3206 format_dev_t(devt_str, dev->devt);
3207 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3208 }
3209
3210 return error;
3211}
3212
3213static void device_remove_sys_dev_entry(struct device *dev)
3214{
3215 struct kobject *kobj = device_to_dev_kobj(dev);
3216 char devt_str[15];
3217
3218 if (kobj) {
3219 format_dev_t(devt_str, dev->devt);
3220 sysfs_remove_link(kobj, devt_str);
3221 }
3222}
3223
3224static int device_private_init(struct device *dev)
3225{
3226 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3227 if (!dev->p)
3228 return -ENOMEM;
3229 dev->p->device = dev;
3230 klist_init(&dev->p->klist_children, klist_children_get,
3231 klist_children_put);
3232 INIT_LIST_HEAD(&dev->p->deferred_probe);
3233 return 0;
3234}
3235
3236/**
3237 * device_add - add device to device hierarchy.
3238 * @dev: device.
3239 *
3240 * This is part 2 of device_register(), though may be called
3241 * separately _iff_ device_initialize() has been called separately.
3242 *
3243 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3244 * to the global and sibling lists for the device, then
3245 * adds it to the other relevant subsystems of the driver model.
3246 *
3247 * Do not call this routine or device_register() more than once for
3248 * any device structure. The driver model core is not designed to work
3249 * with devices that get unregistered and then spring back to life.
3250 * (Among other things, it's very hard to guarantee that all references
3251 * to the previous incarnation of @dev have been dropped.) Allocate
3252 * and register a fresh new struct device instead.
3253 *
3254 * NOTE: _Never_ directly free @dev after calling this function, even
3255 * if it returned an error! Always use put_device() to give up your
3256 * reference instead.
3257 *
3258 * Rule of thumb is: if device_add() succeeds, you should call
3259 * device_del() when you want to get rid of it. If device_add() has
3260 * *not* succeeded, use *only* put_device() to drop the reference
3261 * count.
3262 */
3263int device_add(struct device *dev)
3264{
3265 struct device *parent;
3266 struct kobject *kobj;
3267 struct class_interface *class_intf;
3268 int error = -EINVAL;
3269 struct kobject *glue_dir = NULL;
3270
3271 dev = get_device(dev);
3272 if (!dev)
3273 goto done;
3274
3275 if (!dev->p) {
3276 error = device_private_init(dev);
3277 if (error)
3278 goto done;
3279 }
3280
3281 /*
3282 * for statically allocated devices, which should all be converted
3283 * some day, we need to initialize the name. We prevent reading back
3284 * the name, and force the use of dev_name()
3285 */
3286 if (dev->init_name) {
3287 dev_set_name(dev, "%s", dev->init_name);
3288 dev->init_name = NULL;
3289 }
3290
3291 /* subsystems can specify simple device enumeration */
3292 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
3293 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3294
3295 if (!dev_name(dev)) {
3296 error = -EINVAL;
3297 goto name_error;
3298 }
3299
3300 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3301
3302 parent = get_device(dev->parent);
3303 kobj = get_device_parent(dev, parent);
3304 if (IS_ERR(kobj)) {
3305 error = PTR_ERR(kobj);
3306 goto parent_error;
3307 }
3308 if (kobj)
3309 dev->kobj.parent = kobj;
3310
3311 /* use parent numa_node */
3312 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3313 set_dev_node(dev, dev_to_node(parent));
3314
3315 /* first, register with generic layer. */
3316 /* we require the name to be set before, and pass NULL */
3317 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3318 if (error) {
3319 glue_dir = get_glue_dir(dev);
3320 goto Error;
3321 }
3322
3323 /* notify platform of device entry */
3324 error = device_platform_notify(dev, KOBJ_ADD);
3325 if (error)
3326 goto platform_error;
3327
3328 error = device_create_file(dev, &dev_attr_uevent);
3329 if (error)
3330 goto attrError;
3331
3332 error = device_add_class_symlinks(dev);
3333 if (error)
3334 goto SymlinkError;
3335 error = device_add_attrs(dev);
3336 if (error)
3337 goto AttrsError;
3338 error = bus_add_device(dev);
3339 if (error)
3340 goto BusError;
3341 error = dpm_sysfs_add(dev);
3342 if (error)
3343 goto DPMError;
3344 device_pm_add(dev);
3345
3346 if (MAJOR(dev->devt)) {
3347 error = device_create_file(dev, &dev_attr_dev);
3348 if (error)
3349 goto DevAttrError;
3350
3351 error = device_create_sys_dev_entry(dev);
3352 if (error)
3353 goto SysEntryError;
3354
3355 devtmpfs_create_node(dev);
3356 }
3357
3358 /* Notify clients of device addition. This call must come
3359 * after dpm_sysfs_add() and before kobject_uevent().
3360 */
3361 if (dev->bus)
3362 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3363 BUS_NOTIFY_ADD_DEVICE, dev);
3364
3365 kobject_uevent(&dev->kobj, KOBJ_ADD);
3366
3367 /*
3368 * Check if any of the other devices (consumers) have been waiting for
3369 * this device (supplier) to be added so that they can create a device
3370 * link to it.
3371 *
3372 * This needs to happen after device_pm_add() because device_link_add()
3373 * requires the supplier be registered before it's called.
3374 *
3375 * But this also needs to happen before bus_probe_device() to make sure
3376 * waiting consumers can link to it before the driver is bound to the
3377 * device and the driver sync_state callback is called for this device.
3378 */
3379 if (dev->fwnode && !dev->fwnode->dev) {
3380 dev->fwnode->dev = dev;
3381 fw_devlink_link_device(dev);
3382 }
3383
3384 bus_probe_device(dev);
3385
3386 /*
3387 * If all driver registration is done and a newly added device doesn't
3388 * match with any driver, don't block its consumers from probing in
3389 * case the consumer device is able to operate without this supplier.
3390 */
3391 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3392 fw_devlink_unblock_consumers(dev);
3393
3394 if (parent)
3395 klist_add_tail(&dev->p->knode_parent,
3396 &parent->p->klist_children);
3397
3398 if (dev->class) {
3399 mutex_lock(&dev->class->p->mutex);
3400 /* tie the class to the device */
3401 klist_add_tail(&dev->p->knode_class,
3402 &dev->class->p->klist_devices);
3403
3404 /* notify any interfaces that the device is here */
3405 list_for_each_entry(class_intf,
3406 &dev->class->p->interfaces, node)
3407 if (class_intf->add_dev)
3408 class_intf->add_dev(dev, class_intf);
3409 mutex_unlock(&dev->class->p->mutex);
3410 }
3411done:
3412 put_device(dev);
3413 return error;
3414 SysEntryError:
3415 if (MAJOR(dev->devt))
3416 device_remove_file(dev, &dev_attr_dev);
3417 DevAttrError:
3418 device_pm_remove(dev);
3419 dpm_sysfs_remove(dev);
3420 DPMError:
3421 bus_remove_device(dev);
3422 BusError:
3423 device_remove_attrs(dev);
3424 AttrsError:
3425 device_remove_class_symlinks(dev);
3426 SymlinkError:
3427 device_remove_file(dev, &dev_attr_uevent);
3428 attrError:
3429 device_platform_notify(dev, KOBJ_REMOVE);
3430platform_error:
3431 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3432 glue_dir = get_glue_dir(dev);
3433 kobject_del(&dev->kobj);
3434 Error:
3435 cleanup_glue_dir(dev, glue_dir);
3436parent_error:
3437 put_device(parent);
3438name_error:
3439 kfree(dev->p);
3440 dev->p = NULL;
3441 goto done;
3442}
3443EXPORT_SYMBOL_GPL(device_add);
3444
3445/**
3446 * device_register - register a device with the system.
3447 * @dev: pointer to the device structure
3448 *
3449 * This happens in two clean steps - initialize the device
3450 * and add it to the system. The two steps can be called
3451 * separately, but this is the easiest and most common.
3452 * I.e. you should only call the two helpers separately if
3453 * have a clearly defined need to use and refcount the device
3454 * before it is added to the hierarchy.
3455 *
3456 * For more information, see the kerneldoc for device_initialize()
3457 * and device_add().
3458 *
3459 * NOTE: _Never_ directly free @dev after calling this function, even
3460 * if it returned an error! Always use put_device() to give up the
3461 * reference initialized in this function instead.
3462 */
3463int device_register(struct device *dev)
3464{
3465 device_initialize(dev);
3466 return device_add(dev);
3467}
3468EXPORT_SYMBOL_GPL(device_register);
3469
3470/**
3471 * get_device - increment reference count for device.
3472 * @dev: device.
3473 *
3474 * This simply forwards the call to kobject_get(), though
3475 * we do take care to provide for the case that we get a NULL
3476 * pointer passed in.
3477 */
3478struct device *get_device(struct device *dev)
3479{
3480 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3481}
3482EXPORT_SYMBOL_GPL(get_device);
3483
3484/**
3485 * put_device - decrement reference count.
3486 * @dev: device in question.
3487 */
3488void put_device(struct device *dev)
3489{
3490 /* might_sleep(); */
3491 if (dev)
3492 kobject_put(&dev->kobj);
3493}
3494EXPORT_SYMBOL_GPL(put_device);
3495
3496bool kill_device(struct device *dev)
3497{
3498 /*
3499 * Require the device lock and set the "dead" flag to guarantee that
3500 * the update behavior is consistent with the other bitfields near
3501 * it and that we cannot have an asynchronous probe routine trying
3502 * to run while we are tearing out the bus/class/sysfs from
3503 * underneath the device.
3504 */
3505 device_lock_assert(dev);
3506
3507 if (dev->p->dead)
3508 return false;
3509 dev->p->dead = true;
3510 return true;
3511}
3512EXPORT_SYMBOL_GPL(kill_device);
3513
3514/**
3515 * device_del - delete device from system.
3516 * @dev: device.
3517 *
3518 * This is the first part of the device unregistration
3519 * sequence. This removes the device from the lists we control
3520 * from here, has it removed from the other driver model
3521 * subsystems it was added to in device_add(), and removes it
3522 * from the kobject hierarchy.
3523 *
3524 * NOTE: this should be called manually _iff_ device_add() was
3525 * also called manually.
3526 */
3527void device_del(struct device *dev)
3528{
3529 struct device *parent = dev->parent;
3530 struct kobject *glue_dir = NULL;
3531 struct class_interface *class_intf;
3532 unsigned int noio_flag;
3533
3534 device_lock(dev);
3535 kill_device(dev);
3536 device_unlock(dev);
3537
3538 if (dev->fwnode && dev->fwnode->dev == dev)
3539 dev->fwnode->dev = NULL;
3540
3541 /* Notify clients of device removal. This call must come
3542 * before dpm_sysfs_remove().
3543 */
3544 noio_flag = memalloc_noio_save();
3545 if (dev->bus)
3546 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3547 BUS_NOTIFY_DEL_DEVICE, dev);
3548
3549 dpm_sysfs_remove(dev);
3550 if (parent)
3551 klist_del(&dev->p->knode_parent);
3552 if (MAJOR(dev->devt)) {
3553 devtmpfs_delete_node(dev);
3554 device_remove_sys_dev_entry(dev);
3555 device_remove_file(dev, &dev_attr_dev);
3556 }
3557 if (dev->class) {
3558 device_remove_class_symlinks(dev);
3559
3560 mutex_lock(&dev->class->p->mutex);
3561 /* notify any interfaces that the device is now gone */
3562 list_for_each_entry(class_intf,
3563 &dev->class->p->interfaces, node)
3564 if (class_intf->remove_dev)
3565 class_intf->remove_dev(dev, class_intf);
3566 /* remove the device from the class list */
3567 klist_del(&dev->p->knode_class);
3568 mutex_unlock(&dev->class->p->mutex);
3569 }
3570 device_remove_file(dev, &dev_attr_uevent);
3571 device_remove_attrs(dev);
3572 bus_remove_device(dev);
3573 device_pm_remove(dev);
3574 driver_deferred_probe_del(dev);
3575 device_platform_notify(dev, KOBJ_REMOVE);
3576 device_remove_properties(dev);
3577 device_links_purge(dev);
3578
3579 if (dev->bus)
3580 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3581 BUS_NOTIFY_REMOVED_DEVICE, dev);
3582 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3583 glue_dir = get_glue_dir(dev);
3584 kobject_del(&dev->kobj);
3585 cleanup_glue_dir(dev, glue_dir);
3586 memalloc_noio_restore(noio_flag);
3587 put_device(parent);
3588}
3589EXPORT_SYMBOL_GPL(device_del);
3590
3591/**
3592 * device_unregister - unregister device from system.
3593 * @dev: device going away.
3594 *
3595 * We do this in two parts, like we do device_register(). First,
3596 * we remove it from all the subsystems with device_del(), then
3597 * we decrement the reference count via put_device(). If that
3598 * is the final reference count, the device will be cleaned up
3599 * via device_release() above. Otherwise, the structure will
3600 * stick around until the final reference to the device is dropped.
3601 */
3602void device_unregister(struct device *dev)
3603{
3604 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3605 device_del(dev);
3606 put_device(dev);
3607}
3608EXPORT_SYMBOL_GPL(device_unregister);
3609
3610static struct device *prev_device(struct klist_iter *i)
3611{
3612 struct klist_node *n = klist_prev(i);
3613 struct device *dev = NULL;
3614 struct device_private *p;
3615
3616 if (n) {
3617 p = to_device_private_parent(n);
3618 dev = p->device;
3619 }
3620 return dev;
3621}
3622
3623static struct device *next_device(struct klist_iter *i)
3624{
3625 struct klist_node *n = klist_next(i);
3626 struct device *dev = NULL;
3627 struct device_private *p;
3628
3629 if (n) {
3630 p = to_device_private_parent(n);
3631 dev = p->device;
3632 }
3633 return dev;
3634}
3635
3636/**
3637 * device_get_devnode - path of device node file
3638 * @dev: device
3639 * @mode: returned file access mode
3640 * @uid: returned file owner
3641 * @gid: returned file group
3642 * @tmp: possibly allocated string
3643 *
3644 * Return the relative path of a possible device node.
3645 * Non-default names may need to allocate a memory to compose
3646 * a name. This memory is returned in tmp and needs to be
3647 * freed by the caller.
3648 */
3649const char *device_get_devnode(struct device *dev,
3650 umode_t *mode, kuid_t *uid, kgid_t *gid,
3651 const char **tmp)
3652{
3653 char *s;
3654
3655 *tmp = NULL;
3656
3657 /* the device type may provide a specific name */
3658 if (dev->type && dev->type->devnode)
3659 *tmp = dev->type->devnode(dev, mode, uid, gid);
3660 if (*tmp)
3661 return *tmp;
3662
3663 /* the class may provide a specific name */
3664 if (dev->class && dev->class->devnode)
3665 *tmp = dev->class->devnode(dev, mode);
3666 if (*tmp)
3667 return *tmp;
3668
3669 /* return name without allocation, tmp == NULL */
3670 if (strchr(dev_name(dev), '!') == NULL)
3671 return dev_name(dev);
3672
3673 /* replace '!' in the name with '/' */
3674 s = kstrdup(dev_name(dev), GFP_KERNEL);
3675 if (!s)
3676 return NULL;
3677 strreplace(s, '!', '/');
3678 return *tmp = s;
3679}
3680
3681/**
3682 * device_for_each_child - device child iterator.
3683 * @parent: parent struct device.
3684 * @fn: function to be called for each device.
3685 * @data: data for the callback.
3686 *
3687 * Iterate over @parent's child devices, and call @fn for each,
3688 * passing it @data.
3689 *
3690 * We check the return of @fn each time. If it returns anything
3691 * other than 0, we break out and return that value.
3692 */
3693int device_for_each_child(struct device *parent, void *data,
3694 int (*fn)(struct device *dev, void *data))
3695{
3696 struct klist_iter i;
3697 struct device *child;
3698 int error = 0;
3699
3700 if (!parent->p)
3701 return 0;
3702
3703 klist_iter_init(&parent->p->klist_children, &i);
3704 while (!error && (child = next_device(&i)))
3705 error = fn(child, data);
3706 klist_iter_exit(&i);
3707 return error;
3708}
3709EXPORT_SYMBOL_GPL(device_for_each_child);
3710
3711/**
3712 * device_for_each_child_reverse - device child iterator in reversed order.
3713 * @parent: parent struct device.
3714 * @fn: function to be called for each device.
3715 * @data: data for the callback.
3716 *
3717 * Iterate over @parent's child devices, and call @fn for each,
3718 * passing it @data.
3719 *
3720 * We check the return of @fn each time. If it returns anything
3721 * other than 0, we break out and return that value.
3722 */
3723int device_for_each_child_reverse(struct device *parent, void *data,
3724 int (*fn)(struct device *dev, void *data))
3725{
3726 struct klist_iter i;
3727 struct device *child;
3728 int error = 0;
3729
3730 if (!parent->p)
3731 return 0;
3732
3733 klist_iter_init(&parent->p->klist_children, &i);
3734 while ((child = prev_device(&i)) && !error)
3735 error = fn(child, data);
3736 klist_iter_exit(&i);
3737 return error;
3738}
3739EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3740
3741/**
3742 * device_find_child - device iterator for locating a particular device.
3743 * @parent: parent struct device
3744 * @match: Callback function to check device
3745 * @data: Data to pass to match function
3746 *
3747 * This is similar to the device_for_each_child() function above, but it
3748 * returns a reference to a device that is 'found' for later use, as
3749 * determined by the @match callback.
3750 *
3751 * The callback should return 0 if the device doesn't match and non-zero
3752 * if it does. If the callback returns non-zero and a reference to the
3753 * current device can be obtained, this function will return to the caller
3754 * and not iterate over any more devices.
3755 *
3756 * NOTE: you will need to drop the reference with put_device() after use.
3757 */
3758struct device *device_find_child(struct device *parent, void *data,
3759 int (*match)(struct device *dev, void *data))
3760{
3761 struct klist_iter i;
3762 struct device *child;
3763
3764 if (!parent)
3765 return NULL;
3766
3767 klist_iter_init(&parent->p->klist_children, &i);
3768 while ((child = next_device(&i)))
3769 if (match(child, data) && get_device(child))
3770 break;
3771 klist_iter_exit(&i);
3772 return child;
3773}
3774EXPORT_SYMBOL_GPL(device_find_child);
3775
3776/**
3777 * device_find_child_by_name - device iterator for locating a child device.
3778 * @parent: parent struct device
3779 * @name: name of the child device
3780 *
3781 * This is similar to the device_find_child() function above, but it
3782 * returns a reference to a device that has the name @name.
3783 *
3784 * NOTE: you will need to drop the reference with put_device() after use.
3785 */
3786struct device *device_find_child_by_name(struct device *parent,
3787 const char *name)
3788{
3789 struct klist_iter i;
3790 struct device *child;
3791
3792 if (!parent)
3793 return NULL;
3794
3795 klist_iter_init(&parent->p->klist_children, &i);
3796 while ((child = next_device(&i)))
3797 if (sysfs_streq(dev_name(child), name) && get_device(child))
3798 break;
3799 klist_iter_exit(&i);
3800 return child;
3801}
3802EXPORT_SYMBOL_GPL(device_find_child_by_name);
3803
3804int __init devices_init(void)
3805{
3806 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3807 if (!devices_kset)
3808 return -ENOMEM;
3809 dev_kobj = kobject_create_and_add("dev", NULL);
3810 if (!dev_kobj)
3811 goto dev_kobj_err;
3812 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3813 if (!sysfs_dev_block_kobj)
3814 goto block_kobj_err;
3815 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3816 if (!sysfs_dev_char_kobj)
3817 goto char_kobj_err;
3818
3819 return 0;
3820
3821 char_kobj_err:
3822 kobject_put(sysfs_dev_block_kobj);
3823 block_kobj_err:
3824 kobject_put(dev_kobj);
3825 dev_kobj_err:
3826 kset_unregister(devices_kset);
3827 return -ENOMEM;
3828}
3829
3830static int device_check_offline(struct device *dev, void *not_used)
3831{
3832 int ret;
3833
3834 ret = device_for_each_child(dev, NULL, device_check_offline);
3835 if (ret)
3836 return ret;
3837
3838 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3839}
3840
3841/**
3842 * device_offline - Prepare the device for hot-removal.
3843 * @dev: Device to be put offline.
3844 *
3845 * Execute the device bus type's .offline() callback, if present, to prepare
3846 * the device for a subsequent hot-removal. If that succeeds, the device must
3847 * not be used until either it is removed or its bus type's .online() callback
3848 * is executed.
3849 *
3850 * Call under device_hotplug_lock.
3851 */
3852int device_offline(struct device *dev)
3853{
3854 int ret;
3855
3856 if (dev->offline_disabled)
3857 return -EPERM;
3858
3859 ret = device_for_each_child(dev, NULL, device_check_offline);
3860 if (ret)
3861 return ret;
3862
3863 device_lock(dev);
3864 if (device_supports_offline(dev)) {
3865 if (dev->offline) {
3866 ret = 1;
3867 } else {
3868 ret = dev->bus->offline(dev);
3869 if (!ret) {
3870 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3871 dev->offline = true;
3872 }
3873 }
3874 }
3875 device_unlock(dev);
3876
3877 return ret;
3878}
3879
3880/**
3881 * device_online - Put the device back online after successful device_offline().
3882 * @dev: Device to be put back online.
3883 *
3884 * If device_offline() has been successfully executed for @dev, but the device
3885 * has not been removed subsequently, execute its bus type's .online() callback
3886 * to indicate that the device can be used again.
3887 *
3888 * Call under device_hotplug_lock.
3889 */
3890int device_online(struct device *dev)
3891{
3892 int ret = 0;
3893
3894 device_lock(dev);
3895 if (device_supports_offline(dev)) {
3896 if (dev->offline) {
3897 ret = dev->bus->online(dev);
3898 if (!ret) {
3899 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
3900 dev->offline = false;
3901 }
3902 } else {
3903 ret = 1;
3904 }
3905 }
3906 device_unlock(dev);
3907
3908 return ret;
3909}
3910
3911struct root_device {
3912 struct device dev;
3913 struct module *owner;
3914};
3915
3916static inline struct root_device *to_root_device(struct device *d)
3917{
3918 return container_of(d, struct root_device, dev);
3919}
3920
3921static void root_device_release(struct device *dev)
3922{
3923 kfree(to_root_device(dev));
3924}
3925
3926/**
3927 * __root_device_register - allocate and register a root device
3928 * @name: root device name
3929 * @owner: owner module of the root device, usually THIS_MODULE
3930 *
3931 * This function allocates a root device and registers it
3932 * using device_register(). In order to free the returned
3933 * device, use root_device_unregister().
3934 *
3935 * Root devices are dummy devices which allow other devices
3936 * to be grouped under /sys/devices. Use this function to
3937 * allocate a root device and then use it as the parent of
3938 * any device which should appear under /sys/devices/{name}
3939 *
3940 * The /sys/devices/{name} directory will also contain a
3941 * 'module' symlink which points to the @owner directory
3942 * in sysfs.
3943 *
3944 * Returns &struct device pointer on success, or ERR_PTR() on error.
3945 *
3946 * Note: You probably want to use root_device_register().
3947 */
3948struct device *__root_device_register(const char *name, struct module *owner)
3949{
3950 struct root_device *root;
3951 int err = -ENOMEM;
3952
3953 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
3954 if (!root)
3955 return ERR_PTR(err);
3956
3957 err = dev_set_name(&root->dev, "%s", name);
3958 if (err) {
3959 kfree(root);
3960 return ERR_PTR(err);
3961 }
3962
3963 root->dev.release = root_device_release;
3964
3965 err = device_register(&root->dev);
3966 if (err) {
3967 put_device(&root->dev);
3968 return ERR_PTR(err);
3969 }
3970
3971#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
3972 if (owner) {
3973 struct module_kobject *mk = &owner->mkobj;
3974
3975 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
3976 if (err) {
3977 device_unregister(&root->dev);
3978 return ERR_PTR(err);
3979 }
3980 root->owner = owner;
3981 }
3982#endif
3983
3984 return &root->dev;
3985}
3986EXPORT_SYMBOL_GPL(__root_device_register);
3987
3988/**
3989 * root_device_unregister - unregister and free a root device
3990 * @dev: device going away
3991 *
3992 * This function unregisters and cleans up a device that was created by
3993 * root_device_register().
3994 */
3995void root_device_unregister(struct device *dev)
3996{
3997 struct root_device *root = to_root_device(dev);
3998
3999 if (root->owner)
4000 sysfs_remove_link(&root->dev.kobj, "module");
4001
4002 device_unregister(dev);
4003}
4004EXPORT_SYMBOL_GPL(root_device_unregister);
4005
4006
4007static void device_create_release(struct device *dev)
4008{
4009 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4010 kfree(dev);
4011}
4012
4013static __printf(6, 0) struct device *
4014device_create_groups_vargs(struct class *class, struct device *parent,
4015 dev_t devt, void *drvdata,
4016 const struct attribute_group **groups,
4017 const char *fmt, va_list args)
4018{
4019 struct device *dev = NULL;
4020 int retval = -ENODEV;
4021
4022 if (class == NULL || IS_ERR(class))
4023 goto error;
4024
4025 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4026 if (!dev) {
4027 retval = -ENOMEM;
4028 goto error;
4029 }
4030
4031 device_initialize(dev);
4032 dev->devt = devt;
4033 dev->class = class;
4034 dev->parent = parent;
4035 dev->groups = groups;
4036 dev->release = device_create_release;
4037 dev_set_drvdata(dev, drvdata);
4038
4039 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4040 if (retval)
4041 goto error;
4042
4043 retval = device_add(dev);
4044 if (retval)
4045 goto error;
4046
4047 return dev;
4048
4049error:
4050 put_device(dev);
4051 return ERR_PTR(retval);
4052}
4053
4054/**
4055 * device_create - creates a device and registers it with sysfs
4056 * @class: pointer to the struct class that this device should be registered to
4057 * @parent: pointer to the parent struct device of this new device, if any
4058 * @devt: the dev_t for the char device to be added
4059 * @drvdata: the data to be added to the device for callbacks
4060 * @fmt: string for the device's name
4061 *
4062 * This function can be used by char device classes. A struct device
4063 * will be created in sysfs, registered to the specified class.
4064 *
4065 * A "dev" file will be created, showing the dev_t for the device, if
4066 * the dev_t is not 0,0.
4067 * If a pointer to a parent struct device is passed in, the newly created
4068 * struct device will be a child of that device in sysfs.
4069 * The pointer to the struct device will be returned from the call.
4070 * Any further sysfs files that might be required can be created using this
4071 * pointer.
4072 *
4073 * Returns &struct device pointer on success, or ERR_PTR() on error.
4074 *
4075 * Note: the struct class passed to this function must have previously
4076 * been created with a call to class_create().
4077 */
4078struct device *device_create(struct class *class, struct device *parent,
4079 dev_t devt, void *drvdata, const char *fmt, ...)
4080{
4081 va_list vargs;
4082 struct device *dev;
4083
4084 va_start(vargs, fmt);
4085 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4086 fmt, vargs);
4087 va_end(vargs);
4088 return dev;
4089}
4090EXPORT_SYMBOL_GPL(device_create);
4091
4092/**
4093 * device_create_with_groups - creates a device and registers it with sysfs
4094 * @class: pointer to the struct class that this device should be registered to
4095 * @parent: pointer to the parent struct device of this new device, if any
4096 * @devt: the dev_t for the char device to be added
4097 * @drvdata: the data to be added to the device for callbacks
4098 * @groups: NULL-terminated list of attribute groups to be created
4099 * @fmt: string for the device's name
4100 *
4101 * This function can be used by char device classes. A struct device
4102 * will be created in sysfs, registered to the specified class.
4103 * Additional attributes specified in the groups parameter will also
4104 * be created automatically.
4105 *
4106 * A "dev" file will be created, showing the dev_t for the device, if
4107 * the dev_t is not 0,0.
4108 * If a pointer to a parent struct device is passed in, the newly created
4109 * struct device will be a child of that device in sysfs.
4110 * The pointer to the struct device will be returned from the call.
4111 * Any further sysfs files that might be required can be created using this
4112 * pointer.
4113 *
4114 * Returns &struct device pointer on success, or ERR_PTR() on error.
4115 *
4116 * Note: the struct class passed to this function must have previously
4117 * been created with a call to class_create().
4118 */
4119struct device *device_create_with_groups(struct class *class,
4120 struct device *parent, dev_t devt,
4121 void *drvdata,
4122 const struct attribute_group **groups,
4123 const char *fmt, ...)
4124{
4125 va_list vargs;
4126 struct device *dev;
4127
4128 va_start(vargs, fmt);
4129 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4130 fmt, vargs);
4131 va_end(vargs);
4132 return dev;
4133}
4134EXPORT_SYMBOL_GPL(device_create_with_groups);
4135
4136/**
4137 * device_destroy - removes a device that was created with device_create()
4138 * @class: pointer to the struct class that this device was registered with
4139 * @devt: the dev_t of the device that was previously registered
4140 *
4141 * This call unregisters and cleans up a device that was created with a
4142 * call to device_create().
4143 */
4144void device_destroy(struct class *class, dev_t devt)
4145{
4146 struct device *dev;
4147
4148 dev = class_find_device_by_devt(class, devt);
4149 if (dev) {
4150 put_device(dev);
4151 device_unregister(dev);
4152 }
4153}
4154EXPORT_SYMBOL_GPL(device_destroy);
4155
4156/**
4157 * device_rename - renames a device
4158 * @dev: the pointer to the struct device to be renamed
4159 * @new_name: the new name of the device
4160 *
4161 * It is the responsibility of the caller to provide mutual
4162 * exclusion between two different calls of device_rename
4163 * on the same device to ensure that new_name is valid and
4164 * won't conflict with other devices.
4165 *
4166 * Note: Don't call this function. Currently, the networking layer calls this
4167 * function, but that will change. The following text from Kay Sievers offers
4168 * some insight:
4169 *
4170 * Renaming devices is racy at many levels, symlinks and other stuff are not
4171 * replaced atomically, and you get a "move" uevent, but it's not easy to
4172 * connect the event to the old and new device. Device nodes are not renamed at
4173 * all, there isn't even support for that in the kernel now.
4174 *
4175 * In the meantime, during renaming, your target name might be taken by another
4176 * driver, creating conflicts. Or the old name is taken directly after you
4177 * renamed it -- then you get events for the same DEVPATH, before you even see
4178 * the "move" event. It's just a mess, and nothing new should ever rely on
4179 * kernel device renaming. Besides that, it's not even implemented now for
4180 * other things than (driver-core wise very simple) network devices.
4181 *
4182 * We are currently about to change network renaming in udev to completely
4183 * disallow renaming of devices in the same namespace as the kernel uses,
4184 * because we can't solve the problems properly, that arise with swapping names
4185 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
4186 * be allowed to some other name than eth[0-9]*, for the aforementioned
4187 * reasons.
4188 *
4189 * Make up a "real" name in the driver before you register anything, or add
4190 * some other attributes for userspace to find the device, or use udev to add
4191 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4192 * don't even want to get into that and try to implement the missing pieces in
4193 * the core. We really have other pieces to fix in the driver core mess. :)
4194 */
4195int device_rename(struct device *dev, const char *new_name)
4196{
4197 struct kobject *kobj = &dev->kobj;
4198 char *old_device_name = NULL;
4199 int error;
4200
4201 dev = get_device(dev);
4202 if (!dev)
4203 return -EINVAL;
4204
4205 dev_dbg(dev, "renaming to %s\n", new_name);
4206
4207 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4208 if (!old_device_name) {
4209 error = -ENOMEM;
4210 goto out;
4211 }
4212
4213 if (dev->class) {
4214 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
4215 kobj, old_device_name,
4216 new_name, kobject_namespace(kobj));
4217 if (error)
4218 goto out;
4219 }
4220
4221 error = kobject_rename(kobj, new_name);
4222 if (error)
4223 goto out;
4224
4225out:
4226 put_device(dev);
4227
4228 kfree(old_device_name);
4229
4230 return error;
4231}
4232EXPORT_SYMBOL_GPL(device_rename);
4233
4234static int device_move_class_links(struct device *dev,
4235 struct device *old_parent,
4236 struct device *new_parent)
4237{
4238 int error = 0;
4239
4240 if (old_parent)
4241 sysfs_remove_link(&dev->kobj, "device");
4242 if (new_parent)
4243 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4244 "device");
4245 return error;
4246}
4247
4248/**
4249 * device_move - moves a device to a new parent
4250 * @dev: the pointer to the struct device to be moved
4251 * @new_parent: the new parent of the device (can be NULL)
4252 * @dpm_order: how to reorder the dpm_list
4253 */
4254int device_move(struct device *dev, struct device *new_parent,
4255 enum dpm_order dpm_order)
4256{
4257 int error;
4258 struct device *old_parent;
4259 struct kobject *new_parent_kobj;
4260
4261 dev = get_device(dev);
4262 if (!dev)
4263 return -EINVAL;
4264
4265 device_pm_lock();
4266 new_parent = get_device(new_parent);
4267 new_parent_kobj = get_device_parent(dev, new_parent);
4268 if (IS_ERR(new_parent_kobj)) {
4269 error = PTR_ERR(new_parent_kobj);
4270 put_device(new_parent);
4271 goto out;
4272 }
4273
4274 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4275 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4276 error = kobject_move(&dev->kobj, new_parent_kobj);
4277 if (error) {
4278 cleanup_glue_dir(dev, new_parent_kobj);
4279 put_device(new_parent);
4280 goto out;
4281 }
4282 old_parent = dev->parent;
4283 dev->parent = new_parent;
4284 if (old_parent)
4285 klist_remove(&dev->p->knode_parent);
4286 if (new_parent) {
4287 klist_add_tail(&dev->p->knode_parent,
4288 &new_parent->p->klist_children);
4289 set_dev_node(dev, dev_to_node(new_parent));
4290 }
4291
4292 if (dev->class) {
4293 error = device_move_class_links(dev, old_parent, new_parent);
4294 if (error) {
4295 /* We ignore errors on cleanup since we're hosed anyway... */
4296 device_move_class_links(dev, new_parent, old_parent);
4297 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4298 if (new_parent)
4299 klist_remove(&dev->p->knode_parent);
4300 dev->parent = old_parent;
4301 if (old_parent) {
4302 klist_add_tail(&dev->p->knode_parent,
4303 &old_parent->p->klist_children);
4304 set_dev_node(dev, dev_to_node(old_parent));
4305 }
4306 }
4307 cleanup_glue_dir(dev, new_parent_kobj);
4308 put_device(new_parent);
4309 goto out;
4310 }
4311 }
4312 switch (dpm_order) {
4313 case DPM_ORDER_NONE:
4314 break;
4315 case DPM_ORDER_DEV_AFTER_PARENT:
4316 device_pm_move_after(dev, new_parent);
4317 devices_kset_move_after(dev, new_parent);
4318 break;
4319 case DPM_ORDER_PARENT_BEFORE_DEV:
4320 device_pm_move_before(new_parent, dev);
4321 devices_kset_move_before(new_parent, dev);
4322 break;
4323 case DPM_ORDER_DEV_LAST:
4324 device_pm_move_last(dev);
4325 devices_kset_move_last(dev);
4326 break;
4327 }
4328
4329 put_device(old_parent);
4330out:
4331 device_pm_unlock();
4332 put_device(dev);
4333 return error;
4334}
4335EXPORT_SYMBOL_GPL(device_move);
4336
4337static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4338 kgid_t kgid)
4339{
4340 struct kobject *kobj = &dev->kobj;
4341 struct class *class = dev->class;
4342 const struct device_type *type = dev->type;
4343 int error;
4344
4345 if (class) {
4346 /*
4347 * Change the device groups of the device class for @dev to
4348 * @kuid/@kgid.
4349 */
4350 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4351 kgid);
4352 if (error)
4353 return error;
4354 }
4355
4356 if (type) {
4357 /*
4358 * Change the device groups of the device type for @dev to
4359 * @kuid/@kgid.
4360 */
4361 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4362 kgid);
4363 if (error)
4364 return error;
4365 }
4366
4367 /* Change the device groups of @dev to @kuid/@kgid. */
4368 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4369 if (error)
4370 return error;
4371
4372 if (device_supports_offline(dev) && !dev->offline_disabled) {
4373 /* Change online device attributes of @dev to @kuid/@kgid. */
4374 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4375 kuid, kgid);
4376 if (error)
4377 return error;
4378 }
4379
4380 return 0;
4381}
4382
4383/**
4384 * device_change_owner - change the owner of an existing device.
4385 * @dev: device.
4386 * @kuid: new owner's kuid
4387 * @kgid: new owner's kgid
4388 *
4389 * This changes the owner of @dev and its corresponding sysfs entries to
4390 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4391 * core.
4392 *
4393 * Returns 0 on success or error code on failure.
4394 */
4395int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4396{
4397 int error;
4398 struct kobject *kobj = &dev->kobj;
4399
4400 dev = get_device(dev);
4401 if (!dev)
4402 return -EINVAL;
4403
4404 /*
4405 * Change the kobject and the default attributes and groups of the
4406 * ktype associated with it to @kuid/@kgid.
4407 */
4408 error = sysfs_change_owner(kobj, kuid, kgid);
4409 if (error)
4410 goto out;
4411
4412 /*
4413 * Change the uevent file for @dev to the new owner. The uevent file
4414 * was created in a separate step when @dev got added and we mirror
4415 * that step here.
4416 */
4417 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4418 kgid);
4419 if (error)
4420 goto out;
4421
4422 /*
4423 * Change the device groups, the device groups associated with the
4424 * device class, and the groups associated with the device type of @dev
4425 * to @kuid/@kgid.
4426 */
4427 error = device_attrs_change_owner(dev, kuid, kgid);
4428 if (error)
4429 goto out;
4430
4431 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4432 if (error)
4433 goto out;
4434
4435#ifdef CONFIG_BLOCK
4436 if (sysfs_deprecated && dev->class == &block_class)
4437 goto out;
4438#endif
4439
4440 /*
4441 * Change the owner of the symlink located in the class directory of
4442 * the device class associated with @dev which points to the actual
4443 * directory entry for @dev to @kuid/@kgid. This ensures that the
4444 * symlink shows the same permissions as its target.
4445 */
4446 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
4447 dev_name(dev), kuid, kgid);
4448 if (error)
4449 goto out;
4450
4451out:
4452 put_device(dev);
4453 return error;
4454}
4455EXPORT_SYMBOL_GPL(device_change_owner);
4456
4457/**
4458 * device_shutdown - call ->shutdown() on each device to shutdown.
4459 */
4460void device_shutdown(void)
4461{
4462 struct device *dev, *parent;
4463
4464 wait_for_device_probe();
4465 device_block_probing();
4466
4467 cpufreq_suspend();
4468
4469 spin_lock(&devices_kset->list_lock);
4470 /*
4471 * Walk the devices list backward, shutting down each in turn.
4472 * Beware that device unplug events may also start pulling
4473 * devices offline, even as the system is shutting down.
4474 */
4475 while (!list_empty(&devices_kset->list)) {
4476 dev = list_entry(devices_kset->list.prev, struct device,
4477 kobj.entry);
4478
4479 /*
4480 * hold reference count of device's parent to
4481 * prevent it from being freed because parent's
4482 * lock is to be held
4483 */
4484 parent = get_device(dev->parent);
4485 get_device(dev);
4486 /*
4487 * Make sure the device is off the kset list, in the
4488 * event that dev->*->shutdown() doesn't remove it.
4489 */
4490 list_del_init(&dev->kobj.entry);
4491 spin_unlock(&devices_kset->list_lock);
4492
4493 /* hold lock to avoid race with probe/release */
4494 if (parent)
4495 device_lock(parent);
4496 device_lock(dev);
4497
4498 /* Don't allow any more runtime suspends */
4499 pm_runtime_get_noresume(dev);
4500 pm_runtime_barrier(dev);
4501
4502 if (dev->class && dev->class->shutdown_pre) {
4503 if (initcall_debug)
4504 dev_info(dev, "shutdown_pre\n");
4505 dev->class->shutdown_pre(dev);
4506 }
4507 if (dev->bus && dev->bus->shutdown) {
4508 if (initcall_debug)
4509 dev_info(dev, "shutdown\n");
4510 dev->bus->shutdown(dev);
4511 } else if (dev->driver && dev->driver->shutdown) {
4512 if (initcall_debug)
4513 dev_info(dev, "shutdown\n");
4514 dev->driver->shutdown(dev);
4515 }
4516
4517 device_unlock(dev);
4518 if (parent)
4519 device_unlock(parent);
4520
4521 put_device(dev);
4522 put_device(parent);
4523
4524 spin_lock(&devices_kset->list_lock);
4525 }
4526 spin_unlock(&devices_kset->list_lock);
4527}
4528
4529/*
4530 * Device logging functions
4531 */
4532
4533#ifdef CONFIG_PRINTK
4534static void
4535set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4536{
4537 const char *subsys;
4538
4539 memset(dev_info, 0, sizeof(*dev_info));
4540
4541 if (dev->class)
4542 subsys = dev->class->name;
4543 else if (dev->bus)
4544 subsys = dev->bus->name;
4545 else
4546 return;
4547
4548 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4549
4550 /*
4551 * Add device identifier DEVICE=:
4552 * b12:8 block dev_t
4553 * c127:3 char dev_t
4554 * n8 netdev ifindex
4555 * +sound:card0 subsystem:devname
4556 */
4557 if (MAJOR(dev->devt)) {
4558 char c;
4559
4560 if (strcmp(subsys, "block") == 0)
4561 c = 'b';
4562 else
4563 c = 'c';
4564
4565 snprintf(dev_info->device, sizeof(dev_info->device),
4566 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4567 } else if (strcmp(subsys, "net") == 0) {
4568 struct net_device *net = to_net_dev(dev);
4569
4570 snprintf(dev_info->device, sizeof(dev_info->device),
4571 "n%u", net->ifindex);
4572 } else {
4573 snprintf(dev_info->device, sizeof(dev_info->device),
4574 "+%s:%s", subsys, dev_name(dev));
4575 }
4576}
4577
4578int dev_vprintk_emit(int level, const struct device *dev,
4579 const char *fmt, va_list args)
4580{
4581 struct dev_printk_info dev_info;
4582
4583 set_dev_info(dev, &dev_info);
4584
4585 return vprintk_emit(0, level, &dev_info, fmt, args);
4586}
4587EXPORT_SYMBOL(dev_vprintk_emit);
4588
4589int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4590{
4591 va_list args;
4592 int r;
4593
4594 va_start(args, fmt);
4595
4596 r = dev_vprintk_emit(level, dev, fmt, args);
4597
4598 va_end(args);
4599
4600 return r;
4601}
4602EXPORT_SYMBOL(dev_printk_emit);
4603
4604static void __dev_printk(const char *level, const struct device *dev,
4605 struct va_format *vaf)
4606{
4607 if (dev)
4608 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4609 dev_driver_string(dev), dev_name(dev), vaf);
4610 else
4611 printk("%s(NULL device *): %pV", level, vaf);
4612}
4613
4614void dev_printk(const char *level, const struct device *dev,
4615 const char *fmt, ...)
4616{
4617 struct va_format vaf;
4618 va_list args;
4619
4620 va_start(args, fmt);
4621
4622 vaf.fmt = fmt;
4623 vaf.va = &args;
4624
4625 __dev_printk(level, dev, &vaf);
4626
4627 va_end(args);
4628}
4629EXPORT_SYMBOL(dev_printk);
4630
4631#define define_dev_printk_level(func, kern_level) \
4632void func(const struct device *dev, const char *fmt, ...) \
4633{ \
4634 struct va_format vaf; \
4635 va_list args; \
4636 \
4637 va_start(args, fmt); \
4638 \
4639 vaf.fmt = fmt; \
4640 vaf.va = &args; \
4641 \
4642 __dev_printk(kern_level, dev, &vaf); \
4643 \
4644 va_end(args); \
4645} \
4646EXPORT_SYMBOL(func);
4647
4648define_dev_printk_level(_dev_emerg, KERN_EMERG);
4649define_dev_printk_level(_dev_alert, KERN_ALERT);
4650define_dev_printk_level(_dev_crit, KERN_CRIT);
4651define_dev_printk_level(_dev_err, KERN_ERR);
4652define_dev_printk_level(_dev_warn, KERN_WARNING);
4653define_dev_printk_level(_dev_notice, KERN_NOTICE);
4654define_dev_printk_level(_dev_info, KERN_INFO);
4655
4656#endif
4657
4658/**
4659 * dev_err_probe - probe error check and log helper
4660 * @dev: the pointer to the struct device
4661 * @err: error value to test
4662 * @fmt: printf-style format string
4663 * @...: arguments as specified in the format string
4664 *
4665 * This helper implements common pattern present in probe functions for error
4666 * checking: print debug or error message depending if the error value is
4667 * -EPROBE_DEFER and propagate error upwards.
4668 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4669 * checked later by reading devices_deferred debugfs attribute.
4670 * It replaces code sequence::
4671 *
4672 * if (err != -EPROBE_DEFER)
4673 * dev_err(dev, ...);
4674 * else
4675 * dev_dbg(dev, ...);
4676 * return err;
4677 *
4678 * with::
4679 *
4680 * return dev_err_probe(dev, err, ...);
4681 *
4682 * Returns @err.
4683 *
4684 */
4685int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4686{
4687 struct va_format vaf;
4688 va_list args;
4689
4690 va_start(args, fmt);
4691 vaf.fmt = fmt;
4692 vaf.va = &args;
4693
4694 if (err != -EPROBE_DEFER) {
4695 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4696 } else {
4697 device_set_deferred_probe_reason(dev, &vaf);
4698 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4699 }
4700
4701 va_end(args);
4702
4703 return err;
4704}
4705EXPORT_SYMBOL_GPL(dev_err_probe);
4706
4707static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4708{
4709 return fwnode && !IS_ERR(fwnode->secondary);
4710}
4711
4712/**
4713 * set_primary_fwnode - Change the primary firmware node of a given device.
4714 * @dev: Device to handle.
4715 * @fwnode: New primary firmware node of the device.
4716 *
4717 * Set the device's firmware node pointer to @fwnode, but if a secondary
4718 * firmware node of the device is present, preserve it.
4719 *
4720 * Valid fwnode cases are:
4721 * - primary --> secondary --> -ENODEV
4722 * - primary --> NULL
4723 * - secondary --> -ENODEV
4724 * - NULL
4725 */
4726void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4727{
4728 struct device *parent = dev->parent;
4729 struct fwnode_handle *fn = dev->fwnode;
4730
4731 if (fwnode) {
4732 if (fwnode_is_primary(fn))
4733 fn = fn->secondary;
4734
4735 if (fn) {
4736 WARN_ON(fwnode->secondary);
4737 fwnode->secondary = fn;
4738 }
4739 dev->fwnode = fwnode;
4740 } else {
4741 if (fwnode_is_primary(fn)) {
4742 dev->fwnode = fn->secondary;
4743 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
4744 if (!(parent && fn == parent->fwnode))
4745 fn->secondary = NULL;
4746 } else {
4747 dev->fwnode = NULL;
4748 }
4749 }
4750}
4751EXPORT_SYMBOL_GPL(set_primary_fwnode);
4752
4753/**
4754 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4755 * @dev: Device to handle.
4756 * @fwnode: New secondary firmware node of the device.
4757 *
4758 * If a primary firmware node of the device is present, set its secondary
4759 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4760 * @fwnode.
4761 */
4762void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4763{
4764 if (fwnode)
4765 fwnode->secondary = ERR_PTR(-ENODEV);
4766
4767 if (fwnode_is_primary(dev->fwnode))
4768 dev->fwnode->secondary = fwnode;
4769 else
4770 dev->fwnode = fwnode;
4771}
4772EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4773
4774/**
4775 * device_set_of_node_from_dev - reuse device-tree node of another device
4776 * @dev: device whose device-tree node is being set
4777 * @dev2: device whose device-tree node is being reused
4778 *
4779 * Takes another reference to the new device-tree node after first dropping
4780 * any reference held to the old node.
4781 */
4782void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4783{
4784 of_node_put(dev->of_node);
4785 dev->of_node = of_node_get(dev2->of_node);
4786 dev->of_node_reused = true;
4787}
4788EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4789
4790void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
4791{
4792 dev->fwnode = fwnode;
4793 dev->of_node = to_of_node(fwnode);
4794}
4795EXPORT_SYMBOL_GPL(device_set_node);
4796
4797int device_match_name(struct device *dev, const void *name)
4798{
4799 return sysfs_streq(dev_name(dev), name);
4800}
4801EXPORT_SYMBOL_GPL(device_match_name);
4802
4803int device_match_of_node(struct device *dev, const void *np)
4804{
4805 return dev->of_node == np;
4806}
4807EXPORT_SYMBOL_GPL(device_match_of_node);
4808
4809int device_match_fwnode(struct device *dev, const void *fwnode)
4810{
4811 return dev_fwnode(dev) == fwnode;
4812}
4813EXPORT_SYMBOL_GPL(device_match_fwnode);
4814
4815int device_match_devt(struct device *dev, const void *pdevt)
4816{
4817 return dev->devt == *(dev_t *)pdevt;
4818}
4819EXPORT_SYMBOL_GPL(device_match_devt);
4820
4821int device_match_acpi_dev(struct device *dev, const void *adev)
4822{
4823 return ACPI_COMPANION(dev) == adev;
4824}
4825EXPORT_SYMBOL(device_match_acpi_dev);
4826
4827int device_match_any(struct device *dev, const void *unused)
4828{
4829 return 1;
4830}
4831EXPORT_SYMBOL_GPL(device_match_any);