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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/string.h>
21#include <linux/kdev_t.h>
22#include <linux/notifier.h>
23#include <linux/of.h>
24#include <linux/of_device.h>
25#include <linux/blkdev.h>
26#include <linux/mutex.h>
27#include <linux/pm_runtime.h>
28#include <linux/netdevice.h>
29#include <linux/sched/signal.h>
30#include <linux/sched/mm.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#ifdef CONFIG_SYSFS_DEPRECATED
40#ifdef CONFIG_SYSFS_DEPRECATED_V2
41long sysfs_deprecated = 1;
42#else
43long sysfs_deprecated = 0;
44#endif
45static int __init sysfs_deprecated_setup(char *arg)
46{
47 return kstrtol(arg, 10, &sysfs_deprecated);
48}
49early_param("sysfs.deprecated", sysfs_deprecated_setup);
50#endif
51
52/* Device links support. */
53static LIST_HEAD(deferred_sync);
54static unsigned int defer_sync_state_count = 1;
55static DEFINE_MUTEX(fwnode_link_lock);
56static bool fw_devlink_is_permissive(void);
57static bool fw_devlink_drv_reg_done;
58static bool fw_devlink_best_effort;
59
60/**
61 * fwnode_link_add - Create a link between two fwnode_handles.
62 * @con: Consumer end of the link.
63 * @sup: Supplier end of the link.
64 *
65 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
66 * represents the detail that the firmware lists @sup fwnode as supplying a
67 * resource to @con.
68 *
69 * The driver core will use the fwnode link to create a device link between the
70 * two device objects corresponding to @con and @sup when they are created. The
71 * driver core will automatically delete the fwnode link between @con and @sup
72 * after doing that.
73 *
74 * Attempts to create duplicate links between the same pair of fwnode handles
75 * are ignored and there is no reference counting.
76 */
77int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
78{
79 struct fwnode_link *link;
80 int ret = 0;
81
82 mutex_lock(&fwnode_link_lock);
83
84 list_for_each_entry(link, &sup->consumers, s_hook)
85 if (link->consumer == con)
86 goto out;
87
88 link = kzalloc(sizeof(*link), GFP_KERNEL);
89 if (!link) {
90 ret = -ENOMEM;
91 goto out;
92 }
93
94 link->supplier = sup;
95 INIT_LIST_HEAD(&link->s_hook);
96 link->consumer = con;
97 INIT_LIST_HEAD(&link->c_hook);
98
99 list_add(&link->s_hook, &sup->consumers);
100 list_add(&link->c_hook, &con->suppliers);
101 pr_debug("%pfwP Linked as a fwnode consumer to %pfwP\n",
102 con, sup);
103out:
104 mutex_unlock(&fwnode_link_lock);
105
106 return ret;
107}
108
109/**
110 * __fwnode_link_del - Delete a link between two fwnode_handles.
111 * @link: the fwnode_link to be deleted
112 *
113 * The fwnode_link_lock needs to be held when this function is called.
114 */
115static void __fwnode_link_del(struct fwnode_link *link)
116{
117 pr_debug("%pfwP Dropping the fwnode link to %pfwP\n",
118 link->consumer, link->supplier);
119 list_del(&link->s_hook);
120 list_del(&link->c_hook);
121 kfree(link);
122}
123
124/**
125 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
126 * @fwnode: fwnode whose supplier links need to be deleted
127 *
128 * Deletes all supplier links connecting directly to @fwnode.
129 */
130static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
131{
132 struct fwnode_link *link, *tmp;
133
134 mutex_lock(&fwnode_link_lock);
135 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
136 __fwnode_link_del(link);
137 mutex_unlock(&fwnode_link_lock);
138}
139
140/**
141 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
142 * @fwnode: fwnode whose consumer links need to be deleted
143 *
144 * Deletes all consumer links connecting directly to @fwnode.
145 */
146static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
147{
148 struct fwnode_link *link, *tmp;
149
150 mutex_lock(&fwnode_link_lock);
151 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
152 __fwnode_link_del(link);
153 mutex_unlock(&fwnode_link_lock);
154}
155
156/**
157 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
158 * @fwnode: fwnode whose links needs to be deleted
159 *
160 * Deletes all links connecting directly to a fwnode.
161 */
162void fwnode_links_purge(struct fwnode_handle *fwnode)
163{
164 fwnode_links_purge_suppliers(fwnode);
165 fwnode_links_purge_consumers(fwnode);
166}
167
168void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
169{
170 struct fwnode_handle *child;
171
172 /* Don't purge consumer links of an added child */
173 if (fwnode->dev)
174 return;
175
176 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
177 fwnode_links_purge_consumers(fwnode);
178
179 fwnode_for_each_available_child_node(fwnode, child)
180 fw_devlink_purge_absent_suppliers(child);
181}
182EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
183
184#ifdef CONFIG_SRCU
185static DEFINE_MUTEX(device_links_lock);
186DEFINE_STATIC_SRCU(device_links_srcu);
187
188static inline void device_links_write_lock(void)
189{
190 mutex_lock(&device_links_lock);
191}
192
193static inline void device_links_write_unlock(void)
194{
195 mutex_unlock(&device_links_lock);
196}
197
198int device_links_read_lock(void) __acquires(&device_links_srcu)
199{
200 return srcu_read_lock(&device_links_srcu);
201}
202
203void device_links_read_unlock(int idx) __releases(&device_links_srcu)
204{
205 srcu_read_unlock(&device_links_srcu, idx);
206}
207
208int device_links_read_lock_held(void)
209{
210 return srcu_read_lock_held(&device_links_srcu);
211}
212
213static void device_link_synchronize_removal(void)
214{
215 synchronize_srcu(&device_links_srcu);
216}
217
218static void device_link_remove_from_lists(struct device_link *link)
219{
220 list_del_rcu(&link->s_node);
221 list_del_rcu(&link->c_node);
222}
223#else /* !CONFIG_SRCU */
224static DECLARE_RWSEM(device_links_lock);
225
226static inline void device_links_write_lock(void)
227{
228 down_write(&device_links_lock);
229}
230
231static inline void device_links_write_unlock(void)
232{
233 up_write(&device_links_lock);
234}
235
236int device_links_read_lock(void)
237{
238 down_read(&device_links_lock);
239 return 0;
240}
241
242void device_links_read_unlock(int not_used)
243{
244 up_read(&device_links_lock);
245}
246
247#ifdef CONFIG_DEBUG_LOCK_ALLOC
248int device_links_read_lock_held(void)
249{
250 return lockdep_is_held(&device_links_lock);
251}
252#endif
253
254static inline void device_link_synchronize_removal(void)
255{
256}
257
258static void device_link_remove_from_lists(struct device_link *link)
259{
260 list_del(&link->s_node);
261 list_del(&link->c_node);
262}
263#endif /* !CONFIG_SRCU */
264
265static bool device_is_ancestor(struct device *dev, struct device *target)
266{
267 while (target->parent) {
268 target = target->parent;
269 if (dev == target)
270 return true;
271 }
272 return false;
273}
274
275/**
276 * device_is_dependent - Check if one device depends on another one
277 * @dev: Device to check dependencies for.
278 * @target: Device to check against.
279 *
280 * Check if @target depends on @dev or any device dependent on it (its child or
281 * its consumer etc). Return 1 if that is the case or 0 otherwise.
282 */
283int device_is_dependent(struct device *dev, void *target)
284{
285 struct device_link *link;
286 int ret;
287
288 /*
289 * The "ancestors" check is needed to catch the case when the target
290 * device has not been completely initialized yet and it is still
291 * missing from the list of children of its parent device.
292 */
293 if (dev == target || device_is_ancestor(dev, target))
294 return 1;
295
296 ret = device_for_each_child(dev, target, device_is_dependent);
297 if (ret)
298 return ret;
299
300 list_for_each_entry(link, &dev->links.consumers, s_node) {
301 if ((link->flags & ~DL_FLAG_INFERRED) ==
302 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
303 continue;
304
305 if (link->consumer == target)
306 return 1;
307
308 ret = device_is_dependent(link->consumer, target);
309 if (ret)
310 break;
311 }
312 return ret;
313}
314
315static void device_link_init_status(struct device_link *link,
316 struct device *consumer,
317 struct device *supplier)
318{
319 switch (supplier->links.status) {
320 case DL_DEV_PROBING:
321 switch (consumer->links.status) {
322 case DL_DEV_PROBING:
323 /*
324 * A consumer driver can create a link to a supplier
325 * that has not completed its probing yet as long as it
326 * knows that the supplier is already functional (for
327 * example, it has just acquired some resources from the
328 * supplier).
329 */
330 link->status = DL_STATE_CONSUMER_PROBE;
331 break;
332 default:
333 link->status = DL_STATE_DORMANT;
334 break;
335 }
336 break;
337 case DL_DEV_DRIVER_BOUND:
338 switch (consumer->links.status) {
339 case DL_DEV_PROBING:
340 link->status = DL_STATE_CONSUMER_PROBE;
341 break;
342 case DL_DEV_DRIVER_BOUND:
343 link->status = DL_STATE_ACTIVE;
344 break;
345 default:
346 link->status = DL_STATE_AVAILABLE;
347 break;
348 }
349 break;
350 case DL_DEV_UNBINDING:
351 link->status = DL_STATE_SUPPLIER_UNBIND;
352 break;
353 default:
354 link->status = DL_STATE_DORMANT;
355 break;
356 }
357}
358
359static int device_reorder_to_tail(struct device *dev, void *not_used)
360{
361 struct device_link *link;
362
363 /*
364 * Devices that have not been registered yet will be put to the ends
365 * of the lists during the registration, so skip them here.
366 */
367 if (device_is_registered(dev))
368 devices_kset_move_last(dev);
369
370 if (device_pm_initialized(dev))
371 device_pm_move_last(dev);
372
373 device_for_each_child(dev, NULL, device_reorder_to_tail);
374 list_for_each_entry(link, &dev->links.consumers, s_node) {
375 if ((link->flags & ~DL_FLAG_INFERRED) ==
376 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
377 continue;
378 device_reorder_to_tail(link->consumer, NULL);
379 }
380
381 return 0;
382}
383
384/**
385 * device_pm_move_to_tail - Move set of devices to the end of device lists
386 * @dev: Device to move
387 *
388 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
389 *
390 * It moves the @dev along with all of its children and all of its consumers
391 * to the ends of the device_kset and dpm_list, recursively.
392 */
393void device_pm_move_to_tail(struct device *dev)
394{
395 int idx;
396
397 idx = device_links_read_lock();
398 device_pm_lock();
399 device_reorder_to_tail(dev, NULL);
400 device_pm_unlock();
401 device_links_read_unlock(idx);
402}
403
404#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
405
406static ssize_t status_show(struct device *dev,
407 struct device_attribute *attr, char *buf)
408{
409 const char *output;
410
411 switch (to_devlink(dev)->status) {
412 case DL_STATE_NONE:
413 output = "not tracked";
414 break;
415 case DL_STATE_DORMANT:
416 output = "dormant";
417 break;
418 case DL_STATE_AVAILABLE:
419 output = "available";
420 break;
421 case DL_STATE_CONSUMER_PROBE:
422 output = "consumer probing";
423 break;
424 case DL_STATE_ACTIVE:
425 output = "active";
426 break;
427 case DL_STATE_SUPPLIER_UNBIND:
428 output = "supplier unbinding";
429 break;
430 default:
431 output = "unknown";
432 break;
433 }
434
435 return sysfs_emit(buf, "%s\n", output);
436}
437static DEVICE_ATTR_RO(status);
438
439static ssize_t auto_remove_on_show(struct device *dev,
440 struct device_attribute *attr, char *buf)
441{
442 struct device_link *link = to_devlink(dev);
443 const char *output;
444
445 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
446 output = "supplier unbind";
447 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
448 output = "consumer unbind";
449 else
450 output = "never";
451
452 return sysfs_emit(buf, "%s\n", output);
453}
454static DEVICE_ATTR_RO(auto_remove_on);
455
456static ssize_t runtime_pm_show(struct device *dev,
457 struct device_attribute *attr, char *buf)
458{
459 struct device_link *link = to_devlink(dev);
460
461 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
462}
463static DEVICE_ATTR_RO(runtime_pm);
464
465static ssize_t sync_state_only_show(struct device *dev,
466 struct device_attribute *attr, char *buf)
467{
468 struct device_link *link = to_devlink(dev);
469
470 return sysfs_emit(buf, "%d\n",
471 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
472}
473static DEVICE_ATTR_RO(sync_state_only);
474
475static struct attribute *devlink_attrs[] = {
476 &dev_attr_status.attr,
477 &dev_attr_auto_remove_on.attr,
478 &dev_attr_runtime_pm.attr,
479 &dev_attr_sync_state_only.attr,
480 NULL,
481};
482ATTRIBUTE_GROUPS(devlink);
483
484static void device_link_release_fn(struct work_struct *work)
485{
486 struct device_link *link = container_of(work, struct device_link, rm_work);
487
488 /* Ensure that all references to the link object have been dropped. */
489 device_link_synchronize_removal();
490
491 pm_runtime_release_supplier(link);
492 /*
493 * If supplier_preactivated is set, the link has been dropped between
494 * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
495 * in __driver_probe_device(). In that case, drop the supplier's
496 * PM-runtime usage counter to remove the reference taken by
497 * pm_runtime_get_suppliers().
498 */
499 if (link->supplier_preactivated)
500 pm_runtime_put_noidle(link->supplier);
501
502 pm_request_idle(link->supplier);
503
504 put_device(link->consumer);
505 put_device(link->supplier);
506 kfree(link);
507}
508
509static void devlink_dev_release(struct device *dev)
510{
511 struct device_link *link = to_devlink(dev);
512
513 INIT_WORK(&link->rm_work, device_link_release_fn);
514 /*
515 * It may take a while to complete this work because of the SRCU
516 * synchronization in device_link_release_fn() and if the consumer or
517 * supplier devices get deleted when it runs, so put it into the "long"
518 * workqueue.
519 */
520 queue_work(system_long_wq, &link->rm_work);
521}
522
523static struct class devlink_class = {
524 .name = "devlink",
525 .owner = THIS_MODULE,
526 .dev_groups = devlink_groups,
527 .dev_release = devlink_dev_release,
528};
529
530static int devlink_add_symlinks(struct device *dev,
531 struct class_interface *class_intf)
532{
533 int ret;
534 size_t len;
535 struct device_link *link = to_devlink(dev);
536 struct device *sup = link->supplier;
537 struct device *con = link->consumer;
538 char *buf;
539
540 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
541 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
542 len += strlen(":");
543 len += strlen("supplier:") + 1;
544 buf = kzalloc(len, GFP_KERNEL);
545 if (!buf)
546 return -ENOMEM;
547
548 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
549 if (ret)
550 goto out;
551
552 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
553 if (ret)
554 goto err_con;
555
556 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
557 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
558 if (ret)
559 goto err_con_dev;
560
561 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
562 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
563 if (ret)
564 goto err_sup_dev;
565
566 goto out;
567
568err_sup_dev:
569 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
570 sysfs_remove_link(&sup->kobj, buf);
571err_con_dev:
572 sysfs_remove_link(&link->link_dev.kobj, "consumer");
573err_con:
574 sysfs_remove_link(&link->link_dev.kobj, "supplier");
575out:
576 kfree(buf);
577 return ret;
578}
579
580static void devlink_remove_symlinks(struct device *dev,
581 struct class_interface *class_intf)
582{
583 struct device_link *link = to_devlink(dev);
584 size_t len;
585 struct device *sup = link->supplier;
586 struct device *con = link->consumer;
587 char *buf;
588
589 sysfs_remove_link(&link->link_dev.kobj, "consumer");
590 sysfs_remove_link(&link->link_dev.kobj, "supplier");
591
592 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
593 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
594 len += strlen(":");
595 len += strlen("supplier:") + 1;
596 buf = kzalloc(len, GFP_KERNEL);
597 if (!buf) {
598 WARN(1, "Unable to properly free device link symlinks!\n");
599 return;
600 }
601
602 if (device_is_registered(con)) {
603 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
604 sysfs_remove_link(&con->kobj, buf);
605 }
606 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
607 sysfs_remove_link(&sup->kobj, buf);
608 kfree(buf);
609}
610
611static struct class_interface devlink_class_intf = {
612 .class = &devlink_class,
613 .add_dev = devlink_add_symlinks,
614 .remove_dev = devlink_remove_symlinks,
615};
616
617static int __init devlink_class_init(void)
618{
619 int ret;
620
621 ret = class_register(&devlink_class);
622 if (ret)
623 return ret;
624
625 ret = class_interface_register(&devlink_class_intf);
626 if (ret)
627 class_unregister(&devlink_class);
628
629 return ret;
630}
631postcore_initcall(devlink_class_init);
632
633#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
634 DL_FLAG_AUTOREMOVE_SUPPLIER | \
635 DL_FLAG_AUTOPROBE_CONSUMER | \
636 DL_FLAG_SYNC_STATE_ONLY | \
637 DL_FLAG_INFERRED)
638
639#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
640 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
641
642/**
643 * device_link_add - Create a link between two devices.
644 * @consumer: Consumer end of the link.
645 * @supplier: Supplier end of the link.
646 * @flags: Link flags.
647 *
648 * The caller is responsible for the proper synchronization of the link creation
649 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
650 * runtime PM framework to take the link into account. Second, if the
651 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
652 * be forced into the active meta state and reference-counted upon the creation
653 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
654 * ignored.
655 *
656 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
657 * expected to release the link returned by it directly with the help of either
658 * device_link_del() or device_link_remove().
659 *
660 * If that flag is not set, however, the caller of this function is handing the
661 * management of the link over to the driver core entirely and its return value
662 * can only be used to check whether or not the link is present. In that case,
663 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
664 * flags can be used to indicate to the driver core when the link can be safely
665 * deleted. Namely, setting one of them in @flags indicates to the driver core
666 * that the link is not going to be used (by the given caller of this function)
667 * after unbinding the consumer or supplier driver, respectively, from its
668 * device, so the link can be deleted at that point. If none of them is set,
669 * the link will be maintained until one of the devices pointed to by it (either
670 * the consumer or the supplier) is unregistered.
671 *
672 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
673 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
674 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
675 * be used to request the driver core to automatically probe for a consumer
676 * driver after successfully binding a driver to the supplier device.
677 *
678 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
679 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
680 * the same time is invalid and will cause NULL to be returned upfront.
681 * However, if a device link between the given @consumer and @supplier pair
682 * exists already when this function is called for them, the existing link will
683 * be returned regardless of its current type and status (the link's flags may
684 * be modified then). The caller of this function is then expected to treat
685 * the link as though it has just been created, so (in particular) if
686 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
687 * explicitly when not needed any more (as stated above).
688 *
689 * A side effect of the link creation is re-ordering of dpm_list and the
690 * devices_kset list by moving the consumer device and all devices depending
691 * on it to the ends of these lists (that does not happen to devices that have
692 * not been registered when this function is called).
693 *
694 * The supplier device is required to be registered when this function is called
695 * and NULL will be returned if that is not the case. The consumer device need
696 * not be registered, however.
697 */
698struct device_link *device_link_add(struct device *consumer,
699 struct device *supplier, u32 flags)
700{
701 struct device_link *link;
702
703 if (!consumer || !supplier || consumer == supplier ||
704 flags & ~DL_ADD_VALID_FLAGS ||
705 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
706 (flags & DL_FLAG_SYNC_STATE_ONLY &&
707 (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) ||
708 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
709 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
710 DL_FLAG_AUTOREMOVE_SUPPLIER)))
711 return NULL;
712
713 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
714 if (pm_runtime_get_sync(supplier) < 0) {
715 pm_runtime_put_noidle(supplier);
716 return NULL;
717 }
718 }
719
720 if (!(flags & DL_FLAG_STATELESS))
721 flags |= DL_FLAG_MANAGED;
722
723 device_links_write_lock();
724 device_pm_lock();
725
726 /*
727 * If the supplier has not been fully registered yet or there is a
728 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
729 * the supplier already in the graph, return NULL. If the link is a
730 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
731 * because it only affects sync_state() callbacks.
732 */
733 if (!device_pm_initialized(supplier)
734 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
735 device_is_dependent(consumer, supplier))) {
736 link = NULL;
737 goto out;
738 }
739
740 /*
741 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
742 * So, only create it if the consumer hasn't probed yet.
743 */
744 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
745 consumer->links.status != DL_DEV_NO_DRIVER &&
746 consumer->links.status != DL_DEV_PROBING) {
747 link = NULL;
748 goto out;
749 }
750
751 /*
752 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
753 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
754 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
755 */
756 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
757 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
758
759 list_for_each_entry(link, &supplier->links.consumers, s_node) {
760 if (link->consumer != consumer)
761 continue;
762
763 if (link->flags & DL_FLAG_INFERRED &&
764 !(flags & DL_FLAG_INFERRED))
765 link->flags &= ~DL_FLAG_INFERRED;
766
767 if (flags & DL_FLAG_PM_RUNTIME) {
768 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
769 pm_runtime_new_link(consumer);
770 link->flags |= DL_FLAG_PM_RUNTIME;
771 }
772 if (flags & DL_FLAG_RPM_ACTIVE)
773 refcount_inc(&link->rpm_active);
774 }
775
776 if (flags & DL_FLAG_STATELESS) {
777 kref_get(&link->kref);
778 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
779 !(link->flags & DL_FLAG_STATELESS)) {
780 link->flags |= DL_FLAG_STATELESS;
781 goto reorder;
782 } else {
783 link->flags |= DL_FLAG_STATELESS;
784 goto out;
785 }
786 }
787
788 /*
789 * If the life time of the link following from the new flags is
790 * longer than indicated by the flags of the existing link,
791 * update the existing link to stay around longer.
792 */
793 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
794 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
795 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
796 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
797 }
798 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
799 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
800 DL_FLAG_AUTOREMOVE_SUPPLIER);
801 }
802 if (!(link->flags & DL_FLAG_MANAGED)) {
803 kref_get(&link->kref);
804 link->flags |= DL_FLAG_MANAGED;
805 device_link_init_status(link, consumer, supplier);
806 }
807 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
808 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
809 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
810 goto reorder;
811 }
812
813 goto out;
814 }
815
816 link = kzalloc(sizeof(*link), GFP_KERNEL);
817 if (!link)
818 goto out;
819
820 refcount_set(&link->rpm_active, 1);
821
822 get_device(supplier);
823 link->supplier = supplier;
824 INIT_LIST_HEAD(&link->s_node);
825 get_device(consumer);
826 link->consumer = consumer;
827 INIT_LIST_HEAD(&link->c_node);
828 link->flags = flags;
829 kref_init(&link->kref);
830
831 link->link_dev.class = &devlink_class;
832 device_set_pm_not_required(&link->link_dev);
833 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
834 dev_bus_name(supplier), dev_name(supplier),
835 dev_bus_name(consumer), dev_name(consumer));
836 if (device_register(&link->link_dev)) {
837 put_device(&link->link_dev);
838 link = NULL;
839 goto out;
840 }
841
842 if (flags & DL_FLAG_PM_RUNTIME) {
843 if (flags & DL_FLAG_RPM_ACTIVE)
844 refcount_inc(&link->rpm_active);
845
846 pm_runtime_new_link(consumer);
847 }
848
849 /* Determine the initial link state. */
850 if (flags & DL_FLAG_STATELESS)
851 link->status = DL_STATE_NONE;
852 else
853 device_link_init_status(link, consumer, supplier);
854
855 /*
856 * Some callers expect the link creation during consumer driver probe to
857 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
858 */
859 if (link->status == DL_STATE_CONSUMER_PROBE &&
860 flags & DL_FLAG_PM_RUNTIME)
861 pm_runtime_resume(supplier);
862
863 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
864 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
865
866 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
867 dev_dbg(consumer,
868 "Linked as a sync state only consumer to %s\n",
869 dev_name(supplier));
870 goto out;
871 }
872
873reorder:
874 /*
875 * Move the consumer and all of the devices depending on it to the end
876 * of dpm_list and the devices_kset list.
877 *
878 * It is necessary to hold dpm_list locked throughout all that or else
879 * we may end up suspending with a wrong ordering of it.
880 */
881 device_reorder_to_tail(consumer, NULL);
882
883 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
884
885out:
886 device_pm_unlock();
887 device_links_write_unlock();
888
889 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
890 pm_runtime_put(supplier);
891
892 return link;
893}
894EXPORT_SYMBOL_GPL(device_link_add);
895
896static void __device_link_del(struct kref *kref)
897{
898 struct device_link *link = container_of(kref, struct device_link, kref);
899
900 dev_dbg(link->consumer, "Dropping the link to %s\n",
901 dev_name(link->supplier));
902
903 pm_runtime_drop_link(link);
904
905 device_link_remove_from_lists(link);
906 device_unregister(&link->link_dev);
907}
908
909static void device_link_put_kref(struct device_link *link)
910{
911 if (link->flags & DL_FLAG_STATELESS)
912 kref_put(&link->kref, __device_link_del);
913 else if (!device_is_registered(link->consumer))
914 __device_link_del(&link->kref);
915 else
916 WARN(1, "Unable to drop a managed device link reference\n");
917}
918
919/**
920 * device_link_del - Delete a stateless link between two devices.
921 * @link: Device link to delete.
922 *
923 * The caller must ensure proper synchronization of this function with runtime
924 * PM. If the link was added multiple times, it needs to be deleted as often.
925 * Care is required for hotplugged devices: Their links are purged on removal
926 * and calling device_link_del() is then no longer allowed.
927 */
928void device_link_del(struct device_link *link)
929{
930 device_links_write_lock();
931 device_link_put_kref(link);
932 device_links_write_unlock();
933}
934EXPORT_SYMBOL_GPL(device_link_del);
935
936/**
937 * device_link_remove - Delete a stateless link between two devices.
938 * @consumer: Consumer end of the link.
939 * @supplier: Supplier end of the link.
940 *
941 * The caller must ensure proper synchronization of this function with runtime
942 * PM.
943 */
944void device_link_remove(void *consumer, struct device *supplier)
945{
946 struct device_link *link;
947
948 if (WARN_ON(consumer == supplier))
949 return;
950
951 device_links_write_lock();
952
953 list_for_each_entry(link, &supplier->links.consumers, s_node) {
954 if (link->consumer == consumer) {
955 device_link_put_kref(link);
956 break;
957 }
958 }
959
960 device_links_write_unlock();
961}
962EXPORT_SYMBOL_GPL(device_link_remove);
963
964static void device_links_missing_supplier(struct device *dev)
965{
966 struct device_link *link;
967
968 list_for_each_entry(link, &dev->links.suppliers, c_node) {
969 if (link->status != DL_STATE_CONSUMER_PROBE)
970 continue;
971
972 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
973 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
974 } else {
975 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
976 WRITE_ONCE(link->status, DL_STATE_DORMANT);
977 }
978 }
979}
980
981static bool dev_is_best_effort(struct device *dev)
982{
983 return (fw_devlink_best_effort && dev->can_match) ||
984 (dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
985}
986
987/**
988 * device_links_check_suppliers - Check presence of supplier drivers.
989 * @dev: Consumer device.
990 *
991 * Check links from this device to any suppliers. Walk the list of the device's
992 * links to suppliers and see if all of them are available. If not, simply
993 * return -EPROBE_DEFER.
994 *
995 * We need to guarantee that the supplier will not go away after the check has
996 * been positive here. It only can go away in __device_release_driver() and
997 * that function checks the device's links to consumers. This means we need to
998 * mark the link as "consumer probe in progress" to make the supplier removal
999 * wait for us to complete (or bad things may happen).
1000 *
1001 * Links without the DL_FLAG_MANAGED flag set are ignored.
1002 */
1003int device_links_check_suppliers(struct device *dev)
1004{
1005 struct device_link *link;
1006 int ret = 0, fwnode_ret = 0;
1007 struct fwnode_handle *sup_fw;
1008
1009 /*
1010 * Device waiting for supplier to become available is not allowed to
1011 * probe.
1012 */
1013 mutex_lock(&fwnode_link_lock);
1014 if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
1015 !fw_devlink_is_permissive()) {
1016 sup_fw = list_first_entry(&dev->fwnode->suppliers,
1017 struct fwnode_link,
1018 c_hook)->supplier;
1019 if (!dev_is_best_effort(dev)) {
1020 fwnode_ret = -EPROBE_DEFER;
1021 dev_err_probe(dev, -EPROBE_DEFER,
1022 "wait for supplier %pfwP\n", sup_fw);
1023 } else {
1024 fwnode_ret = -EAGAIN;
1025 }
1026 }
1027 mutex_unlock(&fwnode_link_lock);
1028 if (fwnode_ret == -EPROBE_DEFER)
1029 return fwnode_ret;
1030
1031 device_links_write_lock();
1032
1033 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1034 if (!(link->flags & DL_FLAG_MANAGED))
1035 continue;
1036
1037 if (link->status != DL_STATE_AVAILABLE &&
1038 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1039
1040 if (dev_is_best_effort(dev) &&
1041 link->flags & DL_FLAG_INFERRED &&
1042 !link->supplier->can_match) {
1043 ret = -EAGAIN;
1044 continue;
1045 }
1046
1047 device_links_missing_supplier(dev);
1048 dev_err_probe(dev, -EPROBE_DEFER,
1049 "supplier %s not ready\n",
1050 dev_name(link->supplier));
1051 ret = -EPROBE_DEFER;
1052 break;
1053 }
1054 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1055 }
1056 dev->links.status = DL_DEV_PROBING;
1057
1058 device_links_write_unlock();
1059
1060 return ret ? ret : fwnode_ret;
1061}
1062
1063/**
1064 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1065 * @dev: Device to call sync_state() on
1066 * @list: List head to queue the @dev on
1067 *
1068 * Queues a device for a sync_state() callback when the device links write lock
1069 * isn't held. This allows the sync_state() execution flow to use device links
1070 * APIs. The caller must ensure this function is called with
1071 * device_links_write_lock() held.
1072 *
1073 * This function does a get_device() to make sure the device is not freed while
1074 * on this list.
1075 *
1076 * So the caller must also ensure that device_links_flush_sync_list() is called
1077 * as soon as the caller releases device_links_write_lock(). This is necessary
1078 * to make sure the sync_state() is called in a timely fashion and the
1079 * put_device() is called on this device.
1080 */
1081static void __device_links_queue_sync_state(struct device *dev,
1082 struct list_head *list)
1083{
1084 struct device_link *link;
1085
1086 if (!dev_has_sync_state(dev))
1087 return;
1088 if (dev->state_synced)
1089 return;
1090
1091 list_for_each_entry(link, &dev->links.consumers, s_node) {
1092 if (!(link->flags & DL_FLAG_MANAGED))
1093 continue;
1094 if (link->status != DL_STATE_ACTIVE)
1095 return;
1096 }
1097
1098 /*
1099 * Set the flag here to avoid adding the same device to a list more
1100 * than once. This can happen if new consumers get added to the device
1101 * and probed before the list is flushed.
1102 */
1103 dev->state_synced = true;
1104
1105 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1106 return;
1107
1108 get_device(dev);
1109 list_add_tail(&dev->links.defer_sync, list);
1110}
1111
1112/**
1113 * device_links_flush_sync_list - Call sync_state() on a list of devices
1114 * @list: List of devices to call sync_state() on
1115 * @dont_lock_dev: Device for which lock is already held by the caller
1116 *
1117 * Calls sync_state() on all the devices that have been queued for it. This
1118 * function is used in conjunction with __device_links_queue_sync_state(). The
1119 * @dont_lock_dev parameter is useful when this function is called from a
1120 * context where a device lock is already held.
1121 */
1122static void device_links_flush_sync_list(struct list_head *list,
1123 struct device *dont_lock_dev)
1124{
1125 struct device *dev, *tmp;
1126
1127 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1128 list_del_init(&dev->links.defer_sync);
1129
1130 if (dev != dont_lock_dev)
1131 device_lock(dev);
1132
1133 if (dev->bus->sync_state)
1134 dev->bus->sync_state(dev);
1135 else if (dev->driver && dev->driver->sync_state)
1136 dev->driver->sync_state(dev);
1137
1138 if (dev != dont_lock_dev)
1139 device_unlock(dev);
1140
1141 put_device(dev);
1142 }
1143}
1144
1145void device_links_supplier_sync_state_pause(void)
1146{
1147 device_links_write_lock();
1148 defer_sync_state_count++;
1149 device_links_write_unlock();
1150}
1151
1152void device_links_supplier_sync_state_resume(void)
1153{
1154 struct device *dev, *tmp;
1155 LIST_HEAD(sync_list);
1156
1157 device_links_write_lock();
1158 if (!defer_sync_state_count) {
1159 WARN(true, "Unmatched sync_state pause/resume!");
1160 goto out;
1161 }
1162 defer_sync_state_count--;
1163 if (defer_sync_state_count)
1164 goto out;
1165
1166 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1167 /*
1168 * Delete from deferred_sync list before queuing it to
1169 * sync_list because defer_sync is used for both lists.
1170 */
1171 list_del_init(&dev->links.defer_sync);
1172 __device_links_queue_sync_state(dev, &sync_list);
1173 }
1174out:
1175 device_links_write_unlock();
1176
1177 device_links_flush_sync_list(&sync_list, NULL);
1178}
1179
1180static int sync_state_resume_initcall(void)
1181{
1182 device_links_supplier_sync_state_resume();
1183 return 0;
1184}
1185late_initcall(sync_state_resume_initcall);
1186
1187static void __device_links_supplier_defer_sync(struct device *sup)
1188{
1189 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1190 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1191}
1192
1193static void device_link_drop_managed(struct device_link *link)
1194{
1195 link->flags &= ~DL_FLAG_MANAGED;
1196 WRITE_ONCE(link->status, DL_STATE_NONE);
1197 kref_put(&link->kref, __device_link_del);
1198}
1199
1200static ssize_t waiting_for_supplier_show(struct device *dev,
1201 struct device_attribute *attr,
1202 char *buf)
1203{
1204 bool val;
1205
1206 device_lock(dev);
1207 val = !list_empty(&dev->fwnode->suppliers);
1208 device_unlock(dev);
1209 return sysfs_emit(buf, "%u\n", val);
1210}
1211static DEVICE_ATTR_RO(waiting_for_supplier);
1212
1213/**
1214 * device_links_force_bind - Prepares device to be force bound
1215 * @dev: Consumer device.
1216 *
1217 * device_bind_driver() force binds a device to a driver without calling any
1218 * driver probe functions. So the consumer really isn't going to wait for any
1219 * supplier before it's bound to the driver. We still want the device link
1220 * states to be sensible when this happens.
1221 *
1222 * In preparation for device_bind_driver(), this function goes through each
1223 * supplier device links and checks if the supplier is bound. If it is, then
1224 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1225 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1226 */
1227void device_links_force_bind(struct device *dev)
1228{
1229 struct device_link *link, *ln;
1230
1231 device_links_write_lock();
1232
1233 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1234 if (!(link->flags & DL_FLAG_MANAGED))
1235 continue;
1236
1237 if (link->status != DL_STATE_AVAILABLE) {
1238 device_link_drop_managed(link);
1239 continue;
1240 }
1241 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1242 }
1243 dev->links.status = DL_DEV_PROBING;
1244
1245 device_links_write_unlock();
1246}
1247
1248/**
1249 * device_links_driver_bound - Update device links after probing its driver.
1250 * @dev: Device to update the links for.
1251 *
1252 * The probe has been successful, so update links from this device to any
1253 * consumers by changing their status to "available".
1254 *
1255 * Also change the status of @dev's links to suppliers to "active".
1256 *
1257 * Links without the DL_FLAG_MANAGED flag set are ignored.
1258 */
1259void device_links_driver_bound(struct device *dev)
1260{
1261 struct device_link *link, *ln;
1262 LIST_HEAD(sync_list);
1263
1264 /*
1265 * If a device binds successfully, it's expected to have created all
1266 * the device links it needs to or make new device links as it needs
1267 * them. So, fw_devlink no longer needs to create device links to any
1268 * of the device's suppliers.
1269 *
1270 * Also, if a child firmware node of this bound device is not added as
1271 * a device by now, assume it is never going to be added and make sure
1272 * other devices don't defer probe indefinitely by waiting for such a
1273 * child device.
1274 */
1275 if (dev->fwnode && dev->fwnode->dev == dev) {
1276 struct fwnode_handle *child;
1277 fwnode_links_purge_suppliers(dev->fwnode);
1278 fwnode_for_each_available_child_node(dev->fwnode, child)
1279 fw_devlink_purge_absent_suppliers(child);
1280 }
1281 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1282
1283 device_links_write_lock();
1284
1285 list_for_each_entry(link, &dev->links.consumers, s_node) {
1286 if (!(link->flags & DL_FLAG_MANAGED))
1287 continue;
1288
1289 /*
1290 * Links created during consumer probe may be in the "consumer
1291 * probe" state to start with if the supplier is still probing
1292 * when they are created and they may become "active" if the
1293 * consumer probe returns first. Skip them here.
1294 */
1295 if (link->status == DL_STATE_CONSUMER_PROBE ||
1296 link->status == DL_STATE_ACTIVE)
1297 continue;
1298
1299 WARN_ON(link->status != DL_STATE_DORMANT);
1300 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1301
1302 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1303 driver_deferred_probe_add(link->consumer);
1304 }
1305
1306 if (defer_sync_state_count)
1307 __device_links_supplier_defer_sync(dev);
1308 else
1309 __device_links_queue_sync_state(dev, &sync_list);
1310
1311 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1312 struct device *supplier;
1313
1314 if (!(link->flags & DL_FLAG_MANAGED))
1315 continue;
1316
1317 supplier = link->supplier;
1318 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1319 /*
1320 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1321 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1322 * save to drop the managed link completely.
1323 */
1324 device_link_drop_managed(link);
1325 } else if (dev_is_best_effort(dev) &&
1326 link->flags & DL_FLAG_INFERRED &&
1327 link->status != DL_STATE_CONSUMER_PROBE &&
1328 !link->supplier->can_match) {
1329 /*
1330 * When dev_is_best_effort() is true, we ignore device
1331 * links to suppliers that don't have a driver. If the
1332 * consumer device still managed to probe, there's no
1333 * point in maintaining a device link in a weird state
1334 * (consumer probed before supplier). So delete it.
1335 */
1336 device_link_drop_managed(link);
1337 } else {
1338 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1339 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1340 }
1341
1342 /*
1343 * This needs to be done even for the deleted
1344 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1345 * device link that was preventing the supplier from getting a
1346 * sync_state() call.
1347 */
1348 if (defer_sync_state_count)
1349 __device_links_supplier_defer_sync(supplier);
1350 else
1351 __device_links_queue_sync_state(supplier, &sync_list);
1352 }
1353
1354 dev->links.status = DL_DEV_DRIVER_BOUND;
1355
1356 device_links_write_unlock();
1357
1358 device_links_flush_sync_list(&sync_list, dev);
1359}
1360
1361/**
1362 * __device_links_no_driver - Update links of a device without a driver.
1363 * @dev: Device without a drvier.
1364 *
1365 * Delete all non-persistent links from this device to any suppliers.
1366 *
1367 * Persistent links stay around, but their status is changed to "available",
1368 * unless they already are in the "supplier unbind in progress" state in which
1369 * case they need not be updated.
1370 *
1371 * Links without the DL_FLAG_MANAGED flag set are ignored.
1372 */
1373static void __device_links_no_driver(struct device *dev)
1374{
1375 struct device_link *link, *ln;
1376
1377 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1378 if (!(link->flags & DL_FLAG_MANAGED))
1379 continue;
1380
1381 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1382 device_link_drop_managed(link);
1383 continue;
1384 }
1385
1386 if (link->status != DL_STATE_CONSUMER_PROBE &&
1387 link->status != DL_STATE_ACTIVE)
1388 continue;
1389
1390 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1391 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1392 } else {
1393 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1394 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1395 }
1396 }
1397
1398 dev->links.status = DL_DEV_NO_DRIVER;
1399}
1400
1401/**
1402 * device_links_no_driver - Update links after failing driver probe.
1403 * @dev: Device whose driver has just failed to probe.
1404 *
1405 * Clean up leftover links to consumers for @dev and invoke
1406 * %__device_links_no_driver() to update links to suppliers for it as
1407 * appropriate.
1408 *
1409 * Links without the DL_FLAG_MANAGED flag set are ignored.
1410 */
1411void device_links_no_driver(struct device *dev)
1412{
1413 struct device_link *link;
1414
1415 device_links_write_lock();
1416
1417 list_for_each_entry(link, &dev->links.consumers, s_node) {
1418 if (!(link->flags & DL_FLAG_MANAGED))
1419 continue;
1420
1421 /*
1422 * The probe has failed, so if the status of the link is
1423 * "consumer probe" or "active", it must have been added by
1424 * a probing consumer while this device was still probing.
1425 * Change its state to "dormant", as it represents a valid
1426 * relationship, but it is not functionally meaningful.
1427 */
1428 if (link->status == DL_STATE_CONSUMER_PROBE ||
1429 link->status == DL_STATE_ACTIVE)
1430 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1431 }
1432
1433 __device_links_no_driver(dev);
1434
1435 device_links_write_unlock();
1436}
1437
1438/**
1439 * device_links_driver_cleanup - Update links after driver removal.
1440 * @dev: Device whose driver has just gone away.
1441 *
1442 * Update links to consumers for @dev by changing their status to "dormant" and
1443 * invoke %__device_links_no_driver() to update links to suppliers for it as
1444 * appropriate.
1445 *
1446 * Links without the DL_FLAG_MANAGED flag set are ignored.
1447 */
1448void device_links_driver_cleanup(struct device *dev)
1449{
1450 struct device_link *link, *ln;
1451
1452 device_links_write_lock();
1453
1454 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1455 if (!(link->flags & DL_FLAG_MANAGED))
1456 continue;
1457
1458 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1459 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1460
1461 /*
1462 * autoremove the links between this @dev and its consumer
1463 * devices that are not active, i.e. where the link state
1464 * has moved to DL_STATE_SUPPLIER_UNBIND.
1465 */
1466 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1467 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1468 device_link_drop_managed(link);
1469
1470 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1471 }
1472
1473 list_del_init(&dev->links.defer_sync);
1474 __device_links_no_driver(dev);
1475
1476 device_links_write_unlock();
1477}
1478
1479/**
1480 * device_links_busy - Check if there are any busy links to consumers.
1481 * @dev: Device to check.
1482 *
1483 * Check each consumer of the device and return 'true' if its link's status
1484 * is one of "consumer probe" or "active" (meaning that the given consumer is
1485 * probing right now or its driver is present). Otherwise, change the link
1486 * state to "supplier unbind" to prevent the consumer from being probed
1487 * successfully going forward.
1488 *
1489 * Return 'false' if there are no probing or active consumers.
1490 *
1491 * Links without the DL_FLAG_MANAGED flag set are ignored.
1492 */
1493bool device_links_busy(struct device *dev)
1494{
1495 struct device_link *link;
1496 bool ret = false;
1497
1498 device_links_write_lock();
1499
1500 list_for_each_entry(link, &dev->links.consumers, s_node) {
1501 if (!(link->flags & DL_FLAG_MANAGED))
1502 continue;
1503
1504 if (link->status == DL_STATE_CONSUMER_PROBE
1505 || link->status == DL_STATE_ACTIVE) {
1506 ret = true;
1507 break;
1508 }
1509 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1510 }
1511
1512 dev->links.status = DL_DEV_UNBINDING;
1513
1514 device_links_write_unlock();
1515 return ret;
1516}
1517
1518/**
1519 * device_links_unbind_consumers - Force unbind consumers of the given device.
1520 * @dev: Device to unbind the consumers of.
1521 *
1522 * Walk the list of links to consumers for @dev and if any of them is in the
1523 * "consumer probe" state, wait for all device probes in progress to complete
1524 * and start over.
1525 *
1526 * If that's not the case, change the status of the link to "supplier unbind"
1527 * and check if the link was in the "active" state. If so, force the consumer
1528 * driver to unbind and start over (the consumer will not re-probe as we have
1529 * changed the state of the link already).
1530 *
1531 * Links without the DL_FLAG_MANAGED flag set are ignored.
1532 */
1533void device_links_unbind_consumers(struct device *dev)
1534{
1535 struct device_link *link;
1536
1537 start:
1538 device_links_write_lock();
1539
1540 list_for_each_entry(link, &dev->links.consumers, s_node) {
1541 enum device_link_state status;
1542
1543 if (!(link->flags & DL_FLAG_MANAGED) ||
1544 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1545 continue;
1546
1547 status = link->status;
1548 if (status == DL_STATE_CONSUMER_PROBE) {
1549 device_links_write_unlock();
1550
1551 wait_for_device_probe();
1552 goto start;
1553 }
1554 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1555 if (status == DL_STATE_ACTIVE) {
1556 struct device *consumer = link->consumer;
1557
1558 get_device(consumer);
1559
1560 device_links_write_unlock();
1561
1562 device_release_driver_internal(consumer, NULL,
1563 consumer->parent);
1564 put_device(consumer);
1565 goto start;
1566 }
1567 }
1568
1569 device_links_write_unlock();
1570}
1571
1572/**
1573 * device_links_purge - Delete existing links to other devices.
1574 * @dev: Target device.
1575 */
1576static void device_links_purge(struct device *dev)
1577{
1578 struct device_link *link, *ln;
1579
1580 if (dev->class == &devlink_class)
1581 return;
1582
1583 /*
1584 * Delete all of the remaining links from this device to any other
1585 * devices (either consumers or suppliers).
1586 */
1587 device_links_write_lock();
1588
1589 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1590 WARN_ON(link->status == DL_STATE_ACTIVE);
1591 __device_link_del(&link->kref);
1592 }
1593
1594 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1595 WARN_ON(link->status != DL_STATE_DORMANT &&
1596 link->status != DL_STATE_NONE);
1597 __device_link_del(&link->kref);
1598 }
1599
1600 device_links_write_unlock();
1601}
1602
1603#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1604 DL_FLAG_SYNC_STATE_ONLY)
1605#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1606 DL_FLAG_AUTOPROBE_CONSUMER)
1607#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1608 DL_FLAG_PM_RUNTIME)
1609
1610static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1611static int __init fw_devlink_setup(char *arg)
1612{
1613 if (!arg)
1614 return -EINVAL;
1615
1616 if (strcmp(arg, "off") == 0) {
1617 fw_devlink_flags = 0;
1618 } else if (strcmp(arg, "permissive") == 0) {
1619 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1620 } else if (strcmp(arg, "on") == 0) {
1621 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1622 } else if (strcmp(arg, "rpm") == 0) {
1623 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1624 }
1625 return 0;
1626}
1627early_param("fw_devlink", fw_devlink_setup);
1628
1629static bool fw_devlink_strict;
1630static int __init fw_devlink_strict_setup(char *arg)
1631{
1632 return kstrtobool(arg, &fw_devlink_strict);
1633}
1634early_param("fw_devlink.strict", fw_devlink_strict_setup);
1635
1636u32 fw_devlink_get_flags(void)
1637{
1638 return fw_devlink_flags;
1639}
1640
1641static bool fw_devlink_is_permissive(void)
1642{
1643 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1644}
1645
1646bool fw_devlink_is_strict(void)
1647{
1648 return fw_devlink_strict && !fw_devlink_is_permissive();
1649}
1650
1651static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1652{
1653 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1654 return;
1655
1656 fwnode_call_int_op(fwnode, add_links);
1657 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1658}
1659
1660static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1661{
1662 struct fwnode_handle *child = NULL;
1663
1664 fw_devlink_parse_fwnode(fwnode);
1665
1666 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1667 fw_devlink_parse_fwtree(child);
1668}
1669
1670static void fw_devlink_relax_link(struct device_link *link)
1671{
1672 if (!(link->flags & DL_FLAG_INFERRED))
1673 return;
1674
1675 if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE))
1676 return;
1677
1678 pm_runtime_drop_link(link);
1679 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1680 dev_dbg(link->consumer, "Relaxing link with %s\n",
1681 dev_name(link->supplier));
1682}
1683
1684static int fw_devlink_no_driver(struct device *dev, void *data)
1685{
1686 struct device_link *link = to_devlink(dev);
1687
1688 if (!link->supplier->can_match)
1689 fw_devlink_relax_link(link);
1690
1691 return 0;
1692}
1693
1694void fw_devlink_drivers_done(void)
1695{
1696 fw_devlink_drv_reg_done = true;
1697 device_links_write_lock();
1698 class_for_each_device(&devlink_class, NULL, NULL,
1699 fw_devlink_no_driver);
1700 device_links_write_unlock();
1701}
1702
1703/**
1704 * wait_for_init_devices_probe - Try to probe any device needed for init
1705 *
1706 * Some devices might need to be probed and bound successfully before the kernel
1707 * boot sequence can finish and move on to init/userspace. For example, a
1708 * network interface might need to be bound to be able to mount a NFS rootfs.
1709 *
1710 * With fw_devlink=on by default, some of these devices might be blocked from
1711 * probing because they are waiting on a optional supplier that doesn't have a
1712 * driver. While fw_devlink will eventually identify such devices and unblock
1713 * the probing automatically, it might be too late by the time it unblocks the
1714 * probing of devices. For example, the IP4 autoconfig might timeout before
1715 * fw_devlink unblocks probing of the network interface.
1716 *
1717 * This function is available to temporarily try and probe all devices that have
1718 * a driver even if some of their suppliers haven't been added or don't have
1719 * drivers.
1720 *
1721 * The drivers can then decide which of the suppliers are optional vs mandatory
1722 * and probe the device if possible. By the time this function returns, all such
1723 * "best effort" probes are guaranteed to be completed. If a device successfully
1724 * probes in this mode, we delete all fw_devlink discovered dependencies of that
1725 * device where the supplier hasn't yet probed successfully because they have to
1726 * be optional dependencies.
1727 *
1728 * Any devices that didn't successfully probe go back to being treated as if
1729 * this function was never called.
1730 *
1731 * This also means that some devices that aren't needed for init and could have
1732 * waited for their optional supplier to probe (when the supplier's module is
1733 * loaded later on) would end up probing prematurely with limited functionality.
1734 * So call this function only when boot would fail without it.
1735 */
1736void __init wait_for_init_devices_probe(void)
1737{
1738 if (!fw_devlink_flags || fw_devlink_is_permissive())
1739 return;
1740
1741 /*
1742 * Wait for all ongoing probes to finish so that the "best effort" is
1743 * only applied to devices that can't probe otherwise.
1744 */
1745 wait_for_device_probe();
1746
1747 pr_info("Trying to probe devices needed for running init ...\n");
1748 fw_devlink_best_effort = true;
1749 driver_deferred_probe_trigger();
1750
1751 /*
1752 * Wait for all "best effort" probes to finish before going back to
1753 * normal enforcement.
1754 */
1755 wait_for_device_probe();
1756 fw_devlink_best_effort = false;
1757}
1758
1759static void fw_devlink_unblock_consumers(struct device *dev)
1760{
1761 struct device_link *link;
1762
1763 if (!fw_devlink_flags || fw_devlink_is_permissive())
1764 return;
1765
1766 device_links_write_lock();
1767 list_for_each_entry(link, &dev->links.consumers, s_node)
1768 fw_devlink_relax_link(link);
1769 device_links_write_unlock();
1770}
1771
1772/**
1773 * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links
1774 * @con: Device to check dependencies for.
1775 * @sup: Device to check against.
1776 *
1777 * Check if @sup depends on @con or any device dependent on it (its child or
1778 * its consumer etc). When such a cyclic dependency is found, convert all
1779 * device links created solely by fw_devlink into SYNC_STATE_ONLY device links.
1780 * This is the equivalent of doing fw_devlink=permissive just between the
1781 * devices in the cycle. We need to do this because, at this point, fw_devlink
1782 * can't tell which of these dependencies is not a real dependency.
1783 *
1784 * Return 1 if a cycle is found. Otherwise, return 0.
1785 */
1786static int fw_devlink_relax_cycle(struct device *con, void *sup)
1787{
1788 struct device_link *link;
1789 int ret;
1790
1791 if (con == sup)
1792 return 1;
1793
1794 ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
1795 if (ret)
1796 return ret;
1797
1798 list_for_each_entry(link, &con->links.consumers, s_node) {
1799 if ((link->flags & ~DL_FLAG_INFERRED) ==
1800 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
1801 continue;
1802
1803 if (!fw_devlink_relax_cycle(link->consumer, sup))
1804 continue;
1805
1806 ret = 1;
1807
1808 fw_devlink_relax_link(link);
1809 }
1810 return ret;
1811}
1812
1813/**
1814 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
1815 * @con: consumer device for the device link
1816 * @sup_handle: fwnode handle of supplier
1817 * @flags: devlink flags
1818 *
1819 * This function will try to create a device link between the consumer device
1820 * @con and the supplier device represented by @sup_handle.
1821 *
1822 * The supplier has to be provided as a fwnode because incorrect cycles in
1823 * fwnode links can sometimes cause the supplier device to never be created.
1824 * This function detects such cases and returns an error if it cannot create a
1825 * device link from the consumer to a missing supplier.
1826 *
1827 * Returns,
1828 * 0 on successfully creating a device link
1829 * -EINVAL if the device link cannot be created as expected
1830 * -EAGAIN if the device link cannot be created right now, but it may be
1831 * possible to do that in the future
1832 */
1833static int fw_devlink_create_devlink(struct device *con,
1834 struct fwnode_handle *sup_handle, u32 flags)
1835{
1836 struct device *sup_dev;
1837 int ret = 0;
1838
1839 /*
1840 * In some cases, a device P might also be a supplier to its child node
1841 * C. However, this would defer the probe of C until the probe of P
1842 * completes successfully. This is perfectly fine in the device driver
1843 * model. device_add() doesn't guarantee probe completion of the device
1844 * by the time it returns.
1845 *
1846 * However, there are a few drivers that assume C will finish probing
1847 * as soon as it's added and before P finishes probing. So, we provide
1848 * a flag to let fw_devlink know not to delay the probe of C until the
1849 * probe of P completes successfully.
1850 *
1851 * When such a flag is set, we can't create device links where P is the
1852 * supplier of C as that would delay the probe of C.
1853 */
1854 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
1855 fwnode_is_ancestor_of(sup_handle, con->fwnode))
1856 return -EINVAL;
1857
1858 sup_dev = get_dev_from_fwnode(sup_handle);
1859 if (sup_dev) {
1860 /*
1861 * If it's one of those drivers that don't actually bind to
1862 * their device using driver core, then don't wait on this
1863 * supplier device indefinitely.
1864 */
1865 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
1866 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
1867 ret = -EINVAL;
1868 goto out;
1869 }
1870
1871 /*
1872 * If this fails, it is due to cycles in device links. Just
1873 * give up on this link and treat it as invalid.
1874 */
1875 if (!device_link_add(con, sup_dev, flags) &&
1876 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
1877 dev_info(con, "Fixing up cyclic dependency with %s\n",
1878 dev_name(sup_dev));
1879 device_links_write_lock();
1880 fw_devlink_relax_cycle(con, sup_dev);
1881 device_links_write_unlock();
1882 device_link_add(con, sup_dev,
1883 FW_DEVLINK_FLAGS_PERMISSIVE);
1884 ret = -EINVAL;
1885 }
1886
1887 goto out;
1888 }
1889
1890 /* Supplier that's already initialized without a struct device. */
1891 if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
1892 return -EINVAL;
1893
1894 /*
1895 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
1896 * cycles. So cycle detection isn't necessary and shouldn't be
1897 * done.
1898 */
1899 if (flags & DL_FLAG_SYNC_STATE_ONLY)
1900 return -EAGAIN;
1901
1902 /*
1903 * If we can't find the supplier device from its fwnode, it might be
1904 * due to a cyclic dependency between fwnodes. Some of these cycles can
1905 * be broken by applying logic. Check for these types of cycles and
1906 * break them so that devices in the cycle probe properly.
1907 *
1908 * If the supplier's parent is dependent on the consumer, then the
1909 * consumer and supplier have a cyclic dependency. Since fw_devlink
1910 * can't tell which of the inferred dependencies are incorrect, don't
1911 * enforce probe ordering between any of the devices in this cyclic
1912 * dependency. Do this by relaxing all the fw_devlink device links in
1913 * this cycle and by treating the fwnode link between the consumer and
1914 * the supplier as an invalid dependency.
1915 */
1916 sup_dev = fwnode_get_next_parent_dev(sup_handle);
1917 if (sup_dev && device_is_dependent(con, sup_dev)) {
1918 dev_info(con, "Fixing up cyclic dependency with %pfwP (%s)\n",
1919 sup_handle, dev_name(sup_dev));
1920 device_links_write_lock();
1921 fw_devlink_relax_cycle(con, sup_dev);
1922 device_links_write_unlock();
1923 ret = -EINVAL;
1924 } else {
1925 /*
1926 * Can't check for cycles or no cycles. So let's try
1927 * again later.
1928 */
1929 ret = -EAGAIN;
1930 }
1931
1932out:
1933 put_device(sup_dev);
1934 return ret;
1935}
1936
1937/**
1938 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
1939 * @dev: Device that needs to be linked to its consumers
1940 *
1941 * This function looks at all the consumer fwnodes of @dev and creates device
1942 * links between the consumer device and @dev (supplier).
1943 *
1944 * If the consumer device has not been added yet, then this function creates a
1945 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
1946 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
1947 * sync_state() callback before the real consumer device gets to be added and
1948 * then probed.
1949 *
1950 * Once device links are created from the real consumer to @dev (supplier), the
1951 * fwnode links are deleted.
1952 */
1953static void __fw_devlink_link_to_consumers(struct device *dev)
1954{
1955 struct fwnode_handle *fwnode = dev->fwnode;
1956 struct fwnode_link *link, *tmp;
1957
1958 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
1959 u32 dl_flags = fw_devlink_get_flags();
1960 struct device *con_dev;
1961 bool own_link = true;
1962 int ret;
1963
1964 con_dev = get_dev_from_fwnode(link->consumer);
1965 /*
1966 * If consumer device is not available yet, make a "proxy"
1967 * SYNC_STATE_ONLY link from the consumer's parent device to
1968 * the supplier device. This is necessary to make sure the
1969 * supplier doesn't get a sync_state() callback before the real
1970 * consumer can create a device link to the supplier.
1971 *
1972 * This proxy link step is needed to handle the case where the
1973 * consumer's parent device is added before the supplier.
1974 */
1975 if (!con_dev) {
1976 con_dev = fwnode_get_next_parent_dev(link->consumer);
1977 /*
1978 * However, if the consumer's parent device is also the
1979 * parent of the supplier, don't create a
1980 * consumer-supplier link from the parent to its child
1981 * device. Such a dependency is impossible.
1982 */
1983 if (con_dev &&
1984 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
1985 put_device(con_dev);
1986 con_dev = NULL;
1987 } else {
1988 own_link = false;
1989 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1990 }
1991 }
1992
1993 if (!con_dev)
1994 continue;
1995
1996 ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags);
1997 put_device(con_dev);
1998 if (!own_link || ret == -EAGAIN)
1999 continue;
2000
2001 __fwnode_link_del(link);
2002 }
2003}
2004
2005/**
2006 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
2007 * @dev: The consumer device that needs to be linked to its suppliers
2008 * @fwnode: Root of the fwnode tree that is used to create device links
2009 *
2010 * This function looks at all the supplier fwnodes of fwnode tree rooted at
2011 * @fwnode and creates device links between @dev (consumer) and all the
2012 * supplier devices of the entire fwnode tree at @fwnode.
2013 *
2014 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
2015 * and the real suppliers of @dev. Once these device links are created, the
2016 * fwnode links are deleted. When such device links are successfully created,
2017 * this function is called recursively on those supplier devices. This is
2018 * needed to detect and break some invalid cycles in fwnode links. See
2019 * fw_devlink_create_devlink() for more details.
2020 *
2021 * In addition, it also looks at all the suppliers of the entire fwnode tree
2022 * because some of the child devices of @dev that have not been added yet
2023 * (because @dev hasn't probed) might already have their suppliers added to
2024 * driver core. So, this function creates SYNC_STATE_ONLY device links between
2025 * @dev (consumer) and these suppliers to make sure they don't execute their
2026 * sync_state() callbacks before these child devices have a chance to create
2027 * their device links. The fwnode links that correspond to the child devices
2028 * aren't delete because they are needed later to create the device links
2029 * between the real consumer and supplier devices.
2030 */
2031static void __fw_devlink_link_to_suppliers(struct device *dev,
2032 struct fwnode_handle *fwnode)
2033{
2034 bool own_link = (dev->fwnode == fwnode);
2035 struct fwnode_link *link, *tmp;
2036 struct fwnode_handle *child = NULL;
2037 u32 dl_flags;
2038
2039 if (own_link)
2040 dl_flags = fw_devlink_get_flags();
2041 else
2042 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
2043
2044 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
2045 int ret;
2046 struct device *sup_dev;
2047 struct fwnode_handle *sup = link->supplier;
2048
2049 ret = fw_devlink_create_devlink(dev, sup, dl_flags);
2050 if (!own_link || ret == -EAGAIN)
2051 continue;
2052
2053 __fwnode_link_del(link);
2054
2055 /* If no device link was created, nothing more to do. */
2056 if (ret)
2057 continue;
2058
2059 /*
2060 * If a device link was successfully created to a supplier, we
2061 * now need to try and link the supplier to all its suppliers.
2062 *
2063 * This is needed to detect and delete false dependencies in
2064 * fwnode links that haven't been converted to a device link
2065 * yet. See comments in fw_devlink_create_devlink() for more
2066 * details on the false dependency.
2067 *
2068 * Without deleting these false dependencies, some devices will
2069 * never probe because they'll keep waiting for their false
2070 * dependency fwnode links to be converted to device links.
2071 */
2072 sup_dev = get_dev_from_fwnode(sup);
2073 __fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode);
2074 put_device(sup_dev);
2075 }
2076
2077 /*
2078 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
2079 * all the descendants. This proxy link step is needed to handle the
2080 * case where the supplier is added before the consumer's parent device
2081 * (@dev).
2082 */
2083 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
2084 __fw_devlink_link_to_suppliers(dev, child);
2085}
2086
2087static void fw_devlink_link_device(struct device *dev)
2088{
2089 struct fwnode_handle *fwnode = dev->fwnode;
2090
2091 if (!fw_devlink_flags)
2092 return;
2093
2094 fw_devlink_parse_fwtree(fwnode);
2095
2096 mutex_lock(&fwnode_link_lock);
2097 __fw_devlink_link_to_consumers(dev);
2098 __fw_devlink_link_to_suppliers(dev, fwnode);
2099 mutex_unlock(&fwnode_link_lock);
2100}
2101
2102/* Device links support end. */
2103
2104int (*platform_notify)(struct device *dev) = NULL;
2105int (*platform_notify_remove)(struct device *dev) = NULL;
2106static struct kobject *dev_kobj;
2107struct kobject *sysfs_dev_char_kobj;
2108struct kobject *sysfs_dev_block_kobj;
2109
2110static DEFINE_MUTEX(device_hotplug_lock);
2111
2112void lock_device_hotplug(void)
2113{
2114 mutex_lock(&device_hotplug_lock);
2115}
2116
2117void unlock_device_hotplug(void)
2118{
2119 mutex_unlock(&device_hotplug_lock);
2120}
2121
2122int lock_device_hotplug_sysfs(void)
2123{
2124 if (mutex_trylock(&device_hotplug_lock))
2125 return 0;
2126
2127 /* Avoid busy looping (5 ms of sleep should do). */
2128 msleep(5);
2129 return restart_syscall();
2130}
2131
2132#ifdef CONFIG_BLOCK
2133static inline int device_is_not_partition(struct device *dev)
2134{
2135 return !(dev->type == &part_type);
2136}
2137#else
2138static inline int device_is_not_partition(struct device *dev)
2139{
2140 return 1;
2141}
2142#endif
2143
2144static void device_platform_notify(struct device *dev)
2145{
2146 acpi_device_notify(dev);
2147
2148 software_node_notify(dev);
2149
2150 if (platform_notify)
2151 platform_notify(dev);
2152}
2153
2154static void device_platform_notify_remove(struct device *dev)
2155{
2156 acpi_device_notify_remove(dev);
2157
2158 software_node_notify_remove(dev);
2159
2160 if (platform_notify_remove)
2161 platform_notify_remove(dev);
2162}
2163
2164/**
2165 * dev_driver_string - Return a device's driver name, if at all possible
2166 * @dev: struct device to get the name of
2167 *
2168 * Will return the device's driver's name if it is bound to a device. If
2169 * the device is not bound to a driver, it will return the name of the bus
2170 * it is attached to. If it is not attached to a bus either, an empty
2171 * string will be returned.
2172 */
2173const char *dev_driver_string(const struct device *dev)
2174{
2175 struct device_driver *drv;
2176
2177 /* dev->driver can change to NULL underneath us because of unbinding,
2178 * so be careful about accessing it. dev->bus and dev->class should
2179 * never change once they are set, so they don't need special care.
2180 */
2181 drv = READ_ONCE(dev->driver);
2182 return drv ? drv->name : dev_bus_name(dev);
2183}
2184EXPORT_SYMBOL(dev_driver_string);
2185
2186#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2187
2188static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2189 char *buf)
2190{
2191 struct device_attribute *dev_attr = to_dev_attr(attr);
2192 struct device *dev = kobj_to_dev(kobj);
2193 ssize_t ret = -EIO;
2194
2195 if (dev_attr->show)
2196 ret = dev_attr->show(dev, dev_attr, buf);
2197 if (ret >= (ssize_t)PAGE_SIZE) {
2198 printk("dev_attr_show: %pS returned bad count\n",
2199 dev_attr->show);
2200 }
2201 return ret;
2202}
2203
2204static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2205 const char *buf, size_t count)
2206{
2207 struct device_attribute *dev_attr = to_dev_attr(attr);
2208 struct device *dev = kobj_to_dev(kobj);
2209 ssize_t ret = -EIO;
2210
2211 if (dev_attr->store)
2212 ret = dev_attr->store(dev, dev_attr, buf, count);
2213 return ret;
2214}
2215
2216static const struct sysfs_ops dev_sysfs_ops = {
2217 .show = dev_attr_show,
2218 .store = dev_attr_store,
2219};
2220
2221#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2222
2223ssize_t device_store_ulong(struct device *dev,
2224 struct device_attribute *attr,
2225 const char *buf, size_t size)
2226{
2227 struct dev_ext_attribute *ea = to_ext_attr(attr);
2228 int ret;
2229 unsigned long new;
2230
2231 ret = kstrtoul(buf, 0, &new);
2232 if (ret)
2233 return ret;
2234 *(unsigned long *)(ea->var) = new;
2235 /* Always return full write size even if we didn't consume all */
2236 return size;
2237}
2238EXPORT_SYMBOL_GPL(device_store_ulong);
2239
2240ssize_t device_show_ulong(struct device *dev,
2241 struct device_attribute *attr,
2242 char *buf)
2243{
2244 struct dev_ext_attribute *ea = to_ext_attr(attr);
2245 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2246}
2247EXPORT_SYMBOL_GPL(device_show_ulong);
2248
2249ssize_t device_store_int(struct device *dev,
2250 struct device_attribute *attr,
2251 const char *buf, size_t size)
2252{
2253 struct dev_ext_attribute *ea = to_ext_attr(attr);
2254 int ret;
2255 long new;
2256
2257 ret = kstrtol(buf, 0, &new);
2258 if (ret)
2259 return ret;
2260
2261 if (new > INT_MAX || new < INT_MIN)
2262 return -EINVAL;
2263 *(int *)(ea->var) = new;
2264 /* Always return full write size even if we didn't consume all */
2265 return size;
2266}
2267EXPORT_SYMBOL_GPL(device_store_int);
2268
2269ssize_t device_show_int(struct device *dev,
2270 struct device_attribute *attr,
2271 char *buf)
2272{
2273 struct dev_ext_attribute *ea = to_ext_attr(attr);
2274
2275 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2276}
2277EXPORT_SYMBOL_GPL(device_show_int);
2278
2279ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2280 const char *buf, size_t size)
2281{
2282 struct dev_ext_attribute *ea = to_ext_attr(attr);
2283
2284 if (kstrtobool(buf, ea->var) < 0)
2285 return -EINVAL;
2286
2287 return size;
2288}
2289EXPORT_SYMBOL_GPL(device_store_bool);
2290
2291ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2292 char *buf)
2293{
2294 struct dev_ext_attribute *ea = to_ext_attr(attr);
2295
2296 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2297}
2298EXPORT_SYMBOL_GPL(device_show_bool);
2299
2300/**
2301 * device_release - free device structure.
2302 * @kobj: device's kobject.
2303 *
2304 * This is called once the reference count for the object
2305 * reaches 0. We forward the call to the device's release
2306 * method, which should handle actually freeing the structure.
2307 */
2308static void device_release(struct kobject *kobj)
2309{
2310 struct device *dev = kobj_to_dev(kobj);
2311 struct device_private *p = dev->p;
2312
2313 /*
2314 * Some platform devices are driven without driver attached
2315 * and managed resources may have been acquired. Make sure
2316 * all resources are released.
2317 *
2318 * Drivers still can add resources into device after device
2319 * is deleted but alive, so release devres here to avoid
2320 * possible memory leak.
2321 */
2322 devres_release_all(dev);
2323
2324 kfree(dev->dma_range_map);
2325
2326 if (dev->release)
2327 dev->release(dev);
2328 else if (dev->type && dev->type->release)
2329 dev->type->release(dev);
2330 else if (dev->class && dev->class->dev_release)
2331 dev->class->dev_release(dev);
2332 else
2333 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",
2334 dev_name(dev));
2335 kfree(p);
2336}
2337
2338static const void *device_namespace(const struct kobject *kobj)
2339{
2340 const struct device *dev = kobj_to_dev(kobj);
2341 const void *ns = NULL;
2342
2343 if (dev->class && dev->class->ns_type)
2344 ns = dev->class->namespace(dev);
2345
2346 return ns;
2347}
2348
2349static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2350{
2351 const struct device *dev = kobj_to_dev(kobj);
2352
2353 if (dev->class && dev->class->get_ownership)
2354 dev->class->get_ownership(dev, uid, gid);
2355}
2356
2357static struct kobj_type device_ktype = {
2358 .release = device_release,
2359 .sysfs_ops = &dev_sysfs_ops,
2360 .namespace = device_namespace,
2361 .get_ownership = device_get_ownership,
2362};
2363
2364
2365static int dev_uevent_filter(const struct kobject *kobj)
2366{
2367 const struct kobj_type *ktype = get_ktype(kobj);
2368
2369 if (ktype == &device_ktype) {
2370 const struct device *dev = kobj_to_dev(kobj);
2371 if (dev->bus)
2372 return 1;
2373 if (dev->class)
2374 return 1;
2375 }
2376 return 0;
2377}
2378
2379static const char *dev_uevent_name(const struct kobject *kobj)
2380{
2381 const struct device *dev = kobj_to_dev(kobj);
2382
2383 if (dev->bus)
2384 return dev->bus->name;
2385 if (dev->class)
2386 return dev->class->name;
2387 return NULL;
2388}
2389
2390static int dev_uevent(struct kobject *kobj, struct kobj_uevent_env *env)
2391{
2392 struct device *dev = kobj_to_dev(kobj);
2393 int retval = 0;
2394
2395 /* add device node properties if present */
2396 if (MAJOR(dev->devt)) {
2397 const char *tmp;
2398 const char *name;
2399 umode_t mode = 0;
2400 kuid_t uid = GLOBAL_ROOT_UID;
2401 kgid_t gid = GLOBAL_ROOT_GID;
2402
2403 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2404 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2405 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2406 if (name) {
2407 add_uevent_var(env, "DEVNAME=%s", name);
2408 if (mode)
2409 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2410 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2411 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2412 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2413 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2414 kfree(tmp);
2415 }
2416 }
2417
2418 if (dev->type && dev->type->name)
2419 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2420
2421 if (dev->driver)
2422 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2423
2424 /* Add common DT information about the device */
2425 of_device_uevent(dev, env);
2426
2427 /* have the bus specific function add its stuff */
2428 if (dev->bus && dev->bus->uevent) {
2429 retval = dev->bus->uevent(dev, env);
2430 if (retval)
2431 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2432 dev_name(dev), __func__, retval);
2433 }
2434
2435 /* have the class specific function add its stuff */
2436 if (dev->class && dev->class->dev_uevent) {
2437 retval = dev->class->dev_uevent(dev, env);
2438 if (retval)
2439 pr_debug("device: '%s': %s: class uevent() "
2440 "returned %d\n", dev_name(dev),
2441 __func__, retval);
2442 }
2443
2444 /* have the device type specific function add its stuff */
2445 if (dev->type && dev->type->uevent) {
2446 retval = dev->type->uevent(dev, env);
2447 if (retval)
2448 pr_debug("device: '%s': %s: dev_type uevent() "
2449 "returned %d\n", dev_name(dev),
2450 __func__, retval);
2451 }
2452
2453 return retval;
2454}
2455
2456static const struct kset_uevent_ops device_uevent_ops = {
2457 .filter = dev_uevent_filter,
2458 .name = dev_uevent_name,
2459 .uevent = dev_uevent,
2460};
2461
2462static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2463 char *buf)
2464{
2465 struct kobject *top_kobj;
2466 struct kset *kset;
2467 struct kobj_uevent_env *env = NULL;
2468 int i;
2469 int len = 0;
2470 int retval;
2471
2472 /* search the kset, the device belongs to */
2473 top_kobj = &dev->kobj;
2474 while (!top_kobj->kset && top_kobj->parent)
2475 top_kobj = top_kobj->parent;
2476 if (!top_kobj->kset)
2477 goto out;
2478
2479 kset = top_kobj->kset;
2480 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2481 goto out;
2482
2483 /* respect filter */
2484 if (kset->uevent_ops && kset->uevent_ops->filter)
2485 if (!kset->uevent_ops->filter(&dev->kobj))
2486 goto out;
2487
2488 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2489 if (!env)
2490 return -ENOMEM;
2491
2492 /* let the kset specific function add its keys */
2493 retval = kset->uevent_ops->uevent(&dev->kobj, env);
2494 if (retval)
2495 goto out;
2496
2497 /* copy keys to file */
2498 for (i = 0; i < env->envp_idx; i++)
2499 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2500out:
2501 kfree(env);
2502 return len;
2503}
2504
2505static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2506 const char *buf, size_t count)
2507{
2508 int rc;
2509
2510 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2511
2512 if (rc) {
2513 dev_err(dev, "uevent: failed to send synthetic uevent: %d\n", rc);
2514 return rc;
2515 }
2516
2517 return count;
2518}
2519static DEVICE_ATTR_RW(uevent);
2520
2521static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2522 char *buf)
2523{
2524 bool val;
2525
2526 device_lock(dev);
2527 val = !dev->offline;
2528 device_unlock(dev);
2529 return sysfs_emit(buf, "%u\n", val);
2530}
2531
2532static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2533 const char *buf, size_t count)
2534{
2535 bool val;
2536 int ret;
2537
2538 ret = kstrtobool(buf, &val);
2539 if (ret < 0)
2540 return ret;
2541
2542 ret = lock_device_hotplug_sysfs();
2543 if (ret)
2544 return ret;
2545
2546 ret = val ? device_online(dev) : device_offline(dev);
2547 unlock_device_hotplug();
2548 return ret < 0 ? ret : count;
2549}
2550static DEVICE_ATTR_RW(online);
2551
2552static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2553 char *buf)
2554{
2555 const char *loc;
2556
2557 switch (dev->removable) {
2558 case DEVICE_REMOVABLE:
2559 loc = "removable";
2560 break;
2561 case DEVICE_FIXED:
2562 loc = "fixed";
2563 break;
2564 default:
2565 loc = "unknown";
2566 }
2567 return sysfs_emit(buf, "%s\n", loc);
2568}
2569static DEVICE_ATTR_RO(removable);
2570
2571int device_add_groups(struct device *dev, const struct attribute_group **groups)
2572{
2573 return sysfs_create_groups(&dev->kobj, groups);
2574}
2575EXPORT_SYMBOL_GPL(device_add_groups);
2576
2577void device_remove_groups(struct device *dev,
2578 const struct attribute_group **groups)
2579{
2580 sysfs_remove_groups(&dev->kobj, groups);
2581}
2582EXPORT_SYMBOL_GPL(device_remove_groups);
2583
2584union device_attr_group_devres {
2585 const struct attribute_group *group;
2586 const struct attribute_group **groups;
2587};
2588
2589static void devm_attr_group_remove(struct device *dev, void *res)
2590{
2591 union device_attr_group_devres *devres = res;
2592 const struct attribute_group *group = devres->group;
2593
2594 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2595 sysfs_remove_group(&dev->kobj, group);
2596}
2597
2598static void devm_attr_groups_remove(struct device *dev, void *res)
2599{
2600 union device_attr_group_devres *devres = res;
2601 const struct attribute_group **groups = devres->groups;
2602
2603 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2604 sysfs_remove_groups(&dev->kobj, groups);
2605}
2606
2607/**
2608 * devm_device_add_group - given a device, create a managed attribute group
2609 * @dev: The device to create the group for
2610 * @grp: The attribute group to create
2611 *
2612 * This function creates a group for the first time. It will explicitly
2613 * warn and error if any of the attribute files being created already exist.
2614 *
2615 * Returns 0 on success or error code on failure.
2616 */
2617int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2618{
2619 union device_attr_group_devres *devres;
2620 int error;
2621
2622 devres = devres_alloc(devm_attr_group_remove,
2623 sizeof(*devres), GFP_KERNEL);
2624 if (!devres)
2625 return -ENOMEM;
2626
2627 error = sysfs_create_group(&dev->kobj, grp);
2628 if (error) {
2629 devres_free(devres);
2630 return error;
2631 }
2632
2633 devres->group = grp;
2634 devres_add(dev, devres);
2635 return 0;
2636}
2637EXPORT_SYMBOL_GPL(devm_device_add_group);
2638
2639/**
2640 * devm_device_add_groups - create a bunch of managed attribute groups
2641 * @dev: The device to create the group for
2642 * @groups: The attribute groups to create, NULL terminated
2643 *
2644 * This function creates a bunch of managed attribute groups. If an error
2645 * occurs when creating a group, all previously created groups will be
2646 * removed, unwinding everything back to the original state when this
2647 * function was called. It will explicitly warn and error if any of the
2648 * attribute files being created already exist.
2649 *
2650 * Returns 0 on success or error code from sysfs_create_group on failure.
2651 */
2652int devm_device_add_groups(struct device *dev,
2653 const struct attribute_group **groups)
2654{
2655 union device_attr_group_devres *devres;
2656 int error;
2657
2658 devres = devres_alloc(devm_attr_groups_remove,
2659 sizeof(*devres), GFP_KERNEL);
2660 if (!devres)
2661 return -ENOMEM;
2662
2663 error = sysfs_create_groups(&dev->kobj, groups);
2664 if (error) {
2665 devres_free(devres);
2666 return error;
2667 }
2668
2669 devres->groups = groups;
2670 devres_add(dev, devres);
2671 return 0;
2672}
2673EXPORT_SYMBOL_GPL(devm_device_add_groups);
2674
2675static int device_add_attrs(struct device *dev)
2676{
2677 struct class *class = dev->class;
2678 const struct device_type *type = dev->type;
2679 int error;
2680
2681 if (class) {
2682 error = device_add_groups(dev, class->dev_groups);
2683 if (error)
2684 return error;
2685 }
2686
2687 if (type) {
2688 error = device_add_groups(dev, type->groups);
2689 if (error)
2690 goto err_remove_class_groups;
2691 }
2692
2693 error = device_add_groups(dev, dev->groups);
2694 if (error)
2695 goto err_remove_type_groups;
2696
2697 if (device_supports_offline(dev) && !dev->offline_disabled) {
2698 error = device_create_file(dev, &dev_attr_online);
2699 if (error)
2700 goto err_remove_dev_groups;
2701 }
2702
2703 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2704 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2705 if (error)
2706 goto err_remove_dev_online;
2707 }
2708
2709 if (dev_removable_is_valid(dev)) {
2710 error = device_create_file(dev, &dev_attr_removable);
2711 if (error)
2712 goto err_remove_dev_waiting_for_supplier;
2713 }
2714
2715 if (dev_add_physical_location(dev)) {
2716 error = device_add_group(dev,
2717 &dev_attr_physical_location_group);
2718 if (error)
2719 goto err_remove_dev_removable;
2720 }
2721
2722 return 0;
2723
2724 err_remove_dev_removable:
2725 device_remove_file(dev, &dev_attr_removable);
2726 err_remove_dev_waiting_for_supplier:
2727 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2728 err_remove_dev_online:
2729 device_remove_file(dev, &dev_attr_online);
2730 err_remove_dev_groups:
2731 device_remove_groups(dev, dev->groups);
2732 err_remove_type_groups:
2733 if (type)
2734 device_remove_groups(dev, type->groups);
2735 err_remove_class_groups:
2736 if (class)
2737 device_remove_groups(dev, class->dev_groups);
2738
2739 return error;
2740}
2741
2742static void device_remove_attrs(struct device *dev)
2743{
2744 struct class *class = dev->class;
2745 const struct device_type *type = dev->type;
2746
2747 if (dev->physical_location) {
2748 device_remove_group(dev, &dev_attr_physical_location_group);
2749 kfree(dev->physical_location);
2750 }
2751
2752 device_remove_file(dev, &dev_attr_removable);
2753 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2754 device_remove_file(dev, &dev_attr_online);
2755 device_remove_groups(dev, dev->groups);
2756
2757 if (type)
2758 device_remove_groups(dev, type->groups);
2759
2760 if (class)
2761 device_remove_groups(dev, class->dev_groups);
2762}
2763
2764static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2765 char *buf)
2766{
2767 return print_dev_t(buf, dev->devt);
2768}
2769static DEVICE_ATTR_RO(dev);
2770
2771/* /sys/devices/ */
2772struct kset *devices_kset;
2773
2774/**
2775 * devices_kset_move_before - Move device in the devices_kset's list.
2776 * @deva: Device to move.
2777 * @devb: Device @deva should come before.
2778 */
2779static void devices_kset_move_before(struct device *deva, struct device *devb)
2780{
2781 if (!devices_kset)
2782 return;
2783 pr_debug("devices_kset: Moving %s before %s\n",
2784 dev_name(deva), dev_name(devb));
2785 spin_lock(&devices_kset->list_lock);
2786 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2787 spin_unlock(&devices_kset->list_lock);
2788}
2789
2790/**
2791 * devices_kset_move_after - Move device in the devices_kset's list.
2792 * @deva: Device to move
2793 * @devb: Device @deva should come after.
2794 */
2795static void devices_kset_move_after(struct device *deva, struct device *devb)
2796{
2797 if (!devices_kset)
2798 return;
2799 pr_debug("devices_kset: Moving %s after %s\n",
2800 dev_name(deva), dev_name(devb));
2801 spin_lock(&devices_kset->list_lock);
2802 list_move(&deva->kobj.entry, &devb->kobj.entry);
2803 spin_unlock(&devices_kset->list_lock);
2804}
2805
2806/**
2807 * devices_kset_move_last - move the device to the end of devices_kset's list.
2808 * @dev: device to move
2809 */
2810void devices_kset_move_last(struct device *dev)
2811{
2812 if (!devices_kset)
2813 return;
2814 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2815 spin_lock(&devices_kset->list_lock);
2816 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2817 spin_unlock(&devices_kset->list_lock);
2818}
2819
2820/**
2821 * device_create_file - create sysfs attribute file for device.
2822 * @dev: device.
2823 * @attr: device attribute descriptor.
2824 */
2825int device_create_file(struct device *dev,
2826 const struct device_attribute *attr)
2827{
2828 int error = 0;
2829
2830 if (dev) {
2831 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2832 "Attribute %s: write permission without 'store'\n",
2833 attr->attr.name);
2834 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2835 "Attribute %s: read permission without 'show'\n",
2836 attr->attr.name);
2837 error = sysfs_create_file(&dev->kobj, &attr->attr);
2838 }
2839
2840 return error;
2841}
2842EXPORT_SYMBOL_GPL(device_create_file);
2843
2844/**
2845 * device_remove_file - remove sysfs attribute file.
2846 * @dev: device.
2847 * @attr: device attribute descriptor.
2848 */
2849void device_remove_file(struct device *dev,
2850 const struct device_attribute *attr)
2851{
2852 if (dev)
2853 sysfs_remove_file(&dev->kobj, &attr->attr);
2854}
2855EXPORT_SYMBOL_GPL(device_remove_file);
2856
2857/**
2858 * device_remove_file_self - remove sysfs attribute file from its own method.
2859 * @dev: device.
2860 * @attr: device attribute descriptor.
2861 *
2862 * See kernfs_remove_self() for details.
2863 */
2864bool device_remove_file_self(struct device *dev,
2865 const struct device_attribute *attr)
2866{
2867 if (dev)
2868 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2869 else
2870 return false;
2871}
2872EXPORT_SYMBOL_GPL(device_remove_file_self);
2873
2874/**
2875 * device_create_bin_file - create sysfs binary attribute file for device.
2876 * @dev: device.
2877 * @attr: device binary attribute descriptor.
2878 */
2879int device_create_bin_file(struct device *dev,
2880 const struct bin_attribute *attr)
2881{
2882 int error = -EINVAL;
2883 if (dev)
2884 error = sysfs_create_bin_file(&dev->kobj, attr);
2885 return error;
2886}
2887EXPORT_SYMBOL_GPL(device_create_bin_file);
2888
2889/**
2890 * device_remove_bin_file - remove sysfs binary attribute file
2891 * @dev: device.
2892 * @attr: device binary attribute descriptor.
2893 */
2894void device_remove_bin_file(struct device *dev,
2895 const struct bin_attribute *attr)
2896{
2897 if (dev)
2898 sysfs_remove_bin_file(&dev->kobj, attr);
2899}
2900EXPORT_SYMBOL_GPL(device_remove_bin_file);
2901
2902static void klist_children_get(struct klist_node *n)
2903{
2904 struct device_private *p = to_device_private_parent(n);
2905 struct device *dev = p->device;
2906
2907 get_device(dev);
2908}
2909
2910static void klist_children_put(struct klist_node *n)
2911{
2912 struct device_private *p = to_device_private_parent(n);
2913 struct device *dev = p->device;
2914
2915 put_device(dev);
2916}
2917
2918/**
2919 * device_initialize - init device structure.
2920 * @dev: device.
2921 *
2922 * This prepares the device for use by other layers by initializing
2923 * its fields.
2924 * It is the first half of device_register(), if called by
2925 * that function, though it can also be called separately, so one
2926 * may use @dev's fields. In particular, get_device()/put_device()
2927 * may be used for reference counting of @dev after calling this
2928 * function.
2929 *
2930 * All fields in @dev must be initialized by the caller to 0, except
2931 * for those explicitly set to some other value. The simplest
2932 * approach is to use kzalloc() to allocate the structure containing
2933 * @dev.
2934 *
2935 * NOTE: Use put_device() to give up your reference instead of freeing
2936 * @dev directly once you have called this function.
2937 */
2938void device_initialize(struct device *dev)
2939{
2940 dev->kobj.kset = devices_kset;
2941 kobject_init(&dev->kobj, &device_ktype);
2942 INIT_LIST_HEAD(&dev->dma_pools);
2943 mutex_init(&dev->mutex);
2944 lockdep_set_novalidate_class(&dev->mutex);
2945 spin_lock_init(&dev->devres_lock);
2946 INIT_LIST_HEAD(&dev->devres_head);
2947 device_pm_init(dev);
2948 set_dev_node(dev, NUMA_NO_NODE);
2949 INIT_LIST_HEAD(&dev->links.consumers);
2950 INIT_LIST_HEAD(&dev->links.suppliers);
2951 INIT_LIST_HEAD(&dev->links.defer_sync);
2952 dev->links.status = DL_DEV_NO_DRIVER;
2953#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
2954 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
2955 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
2956 dev->dma_coherent = dma_default_coherent;
2957#endif
2958#ifdef CONFIG_SWIOTLB
2959 dev->dma_io_tlb_mem = &io_tlb_default_mem;
2960#endif
2961}
2962EXPORT_SYMBOL_GPL(device_initialize);
2963
2964struct kobject *virtual_device_parent(struct device *dev)
2965{
2966 static struct kobject *virtual_dir = NULL;
2967
2968 if (!virtual_dir)
2969 virtual_dir = kobject_create_and_add("virtual",
2970 &devices_kset->kobj);
2971
2972 return virtual_dir;
2973}
2974
2975struct class_dir {
2976 struct kobject kobj;
2977 struct class *class;
2978};
2979
2980#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2981
2982static void class_dir_release(struct kobject *kobj)
2983{
2984 struct class_dir *dir = to_class_dir(kobj);
2985 kfree(dir);
2986}
2987
2988static const
2989struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *kobj)
2990{
2991 const struct class_dir *dir = to_class_dir(kobj);
2992 return dir->class->ns_type;
2993}
2994
2995static struct kobj_type class_dir_ktype = {
2996 .release = class_dir_release,
2997 .sysfs_ops = &kobj_sysfs_ops,
2998 .child_ns_type = class_dir_child_ns_type
2999};
3000
3001static struct kobject *
3002class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
3003{
3004 struct class_dir *dir;
3005 int retval;
3006
3007 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
3008 if (!dir)
3009 return ERR_PTR(-ENOMEM);
3010
3011 dir->class = class;
3012 kobject_init(&dir->kobj, &class_dir_ktype);
3013
3014 dir->kobj.kset = &class->p->glue_dirs;
3015
3016 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
3017 if (retval < 0) {
3018 kobject_put(&dir->kobj);
3019 return ERR_PTR(retval);
3020 }
3021 return &dir->kobj;
3022}
3023
3024static DEFINE_MUTEX(gdp_mutex);
3025
3026static struct kobject *get_device_parent(struct device *dev,
3027 struct device *parent)
3028{
3029 if (dev->class) {
3030 struct kobject *kobj = NULL;
3031 struct kobject *parent_kobj;
3032 struct kobject *k;
3033
3034#ifdef CONFIG_BLOCK
3035 /* block disks show up in /sys/block */
3036 if (sysfs_deprecated && dev->class == &block_class) {
3037 if (parent && parent->class == &block_class)
3038 return &parent->kobj;
3039 return &block_class.p->subsys.kobj;
3040 }
3041#endif
3042
3043 /*
3044 * If we have no parent, we live in "virtual".
3045 * Class-devices with a non class-device as parent, live
3046 * in a "glue" directory to prevent namespace collisions.
3047 */
3048 if (parent == NULL)
3049 parent_kobj = virtual_device_parent(dev);
3050 else if (parent->class && !dev->class->ns_type)
3051 return &parent->kobj;
3052 else
3053 parent_kobj = &parent->kobj;
3054
3055 mutex_lock(&gdp_mutex);
3056
3057 /* find our class-directory at the parent and reference it */
3058 spin_lock(&dev->class->p->glue_dirs.list_lock);
3059 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
3060 if (k->parent == parent_kobj) {
3061 kobj = kobject_get(k);
3062 break;
3063 }
3064 spin_unlock(&dev->class->p->glue_dirs.list_lock);
3065 if (kobj) {
3066 mutex_unlock(&gdp_mutex);
3067 return kobj;
3068 }
3069
3070 /* or create a new class-directory at the parent device */
3071 k = class_dir_create_and_add(dev->class, parent_kobj);
3072 /* do not emit an uevent for this simple "glue" directory */
3073 mutex_unlock(&gdp_mutex);
3074 return k;
3075 }
3076
3077 /* subsystems can specify a default root directory for their devices */
3078 if (!parent && dev->bus && dev->bus->dev_root)
3079 return &dev->bus->dev_root->kobj;
3080
3081 if (parent)
3082 return &parent->kobj;
3083 return NULL;
3084}
3085
3086static inline bool live_in_glue_dir(struct kobject *kobj,
3087 struct device *dev)
3088{
3089 if (!kobj || !dev->class ||
3090 kobj->kset != &dev->class->p->glue_dirs)
3091 return false;
3092 return true;
3093}
3094
3095static inline struct kobject *get_glue_dir(struct device *dev)
3096{
3097 return dev->kobj.parent;
3098}
3099
3100/**
3101 * kobject_has_children - Returns whether a kobject has children.
3102 * @kobj: the object to test
3103 *
3104 * This will return whether a kobject has other kobjects as children.
3105 *
3106 * It does NOT account for the presence of attribute files, only sub
3107 * directories. It also assumes there is no concurrent addition or
3108 * removal of such children, and thus relies on external locking.
3109 */
3110static inline bool kobject_has_children(struct kobject *kobj)
3111{
3112 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
3113
3114 return kobj->sd && kobj->sd->dir.subdirs;
3115}
3116
3117/*
3118 * make sure cleaning up dir as the last step, we need to make
3119 * sure .release handler of kobject is run with holding the
3120 * global lock
3121 */
3122static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3123{
3124 unsigned int ref;
3125
3126 /* see if we live in a "glue" directory */
3127 if (!live_in_glue_dir(glue_dir, dev))
3128 return;
3129
3130 mutex_lock(&gdp_mutex);
3131 /**
3132 * There is a race condition between removing glue directory
3133 * and adding a new device under the glue directory.
3134 *
3135 * CPU1: CPU2:
3136 *
3137 * device_add()
3138 * get_device_parent()
3139 * class_dir_create_and_add()
3140 * kobject_add_internal()
3141 * create_dir() // create glue_dir
3142 *
3143 * device_add()
3144 * get_device_parent()
3145 * kobject_get() // get glue_dir
3146 *
3147 * device_del()
3148 * cleanup_glue_dir()
3149 * kobject_del(glue_dir)
3150 *
3151 * kobject_add()
3152 * kobject_add_internal()
3153 * create_dir() // in glue_dir
3154 * sysfs_create_dir_ns()
3155 * kernfs_create_dir_ns(sd)
3156 *
3157 * sysfs_remove_dir() // glue_dir->sd=NULL
3158 * sysfs_put() // free glue_dir->sd
3159 *
3160 * // sd is freed
3161 * kernfs_new_node(sd)
3162 * kernfs_get(glue_dir)
3163 * kernfs_add_one()
3164 * kernfs_put()
3165 *
3166 * Before CPU1 remove last child device under glue dir, if CPU2 add
3167 * a new device under glue dir, the glue_dir kobject reference count
3168 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3169 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3170 * and sysfs_put(). This result in glue_dir->sd is freed.
3171 *
3172 * Then the CPU2 will see a stale "empty" but still potentially used
3173 * glue dir around in kernfs_new_node().
3174 *
3175 * In order to avoid this happening, we also should make sure that
3176 * kernfs_node for glue_dir is released in CPU1 only when refcount
3177 * for glue_dir kobj is 1.
3178 */
3179 ref = kref_read(&glue_dir->kref);
3180 if (!kobject_has_children(glue_dir) && !--ref)
3181 kobject_del(glue_dir);
3182 kobject_put(glue_dir);
3183 mutex_unlock(&gdp_mutex);
3184}
3185
3186static int device_add_class_symlinks(struct device *dev)
3187{
3188 struct device_node *of_node = dev_of_node(dev);
3189 int error;
3190
3191 if (of_node) {
3192 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3193 if (error)
3194 dev_warn(dev, "Error %d creating of_node link\n",error);
3195 /* An error here doesn't warrant bringing down the device */
3196 }
3197
3198 if (!dev->class)
3199 return 0;
3200
3201 error = sysfs_create_link(&dev->kobj,
3202 &dev->class->p->subsys.kobj,
3203 "subsystem");
3204 if (error)
3205 goto out_devnode;
3206
3207 if (dev->parent && device_is_not_partition(dev)) {
3208 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3209 "device");
3210 if (error)
3211 goto out_subsys;
3212 }
3213
3214#ifdef CONFIG_BLOCK
3215 /* /sys/block has directories and does not need symlinks */
3216 if (sysfs_deprecated && dev->class == &block_class)
3217 return 0;
3218#endif
3219
3220 /* link in the class directory pointing to the device */
3221 error = sysfs_create_link(&dev->class->p->subsys.kobj,
3222 &dev->kobj, dev_name(dev));
3223 if (error)
3224 goto out_device;
3225
3226 return 0;
3227
3228out_device:
3229 sysfs_remove_link(&dev->kobj, "device");
3230
3231out_subsys:
3232 sysfs_remove_link(&dev->kobj, "subsystem");
3233out_devnode:
3234 sysfs_remove_link(&dev->kobj, "of_node");
3235 return error;
3236}
3237
3238static void device_remove_class_symlinks(struct device *dev)
3239{
3240 if (dev_of_node(dev))
3241 sysfs_remove_link(&dev->kobj, "of_node");
3242
3243 if (!dev->class)
3244 return;
3245
3246 if (dev->parent && device_is_not_partition(dev))
3247 sysfs_remove_link(&dev->kobj, "device");
3248 sysfs_remove_link(&dev->kobj, "subsystem");
3249#ifdef CONFIG_BLOCK
3250 if (sysfs_deprecated && dev->class == &block_class)
3251 return;
3252#endif
3253 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
3254}
3255
3256/**
3257 * dev_set_name - set a device name
3258 * @dev: device
3259 * @fmt: format string for the device's name
3260 */
3261int dev_set_name(struct device *dev, const char *fmt, ...)
3262{
3263 va_list vargs;
3264 int err;
3265
3266 va_start(vargs, fmt);
3267 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3268 va_end(vargs);
3269 return err;
3270}
3271EXPORT_SYMBOL_GPL(dev_set_name);
3272
3273/**
3274 * device_to_dev_kobj - select a /sys/dev/ directory for the device
3275 * @dev: device
3276 *
3277 * By default we select char/ for new entries. Setting class->dev_obj
3278 * to NULL prevents an entry from being created. class->dev_kobj must
3279 * be set (or cleared) before any devices are registered to the class
3280 * otherwise device_create_sys_dev_entry() and
3281 * device_remove_sys_dev_entry() will disagree about the presence of
3282 * the link.
3283 */
3284static struct kobject *device_to_dev_kobj(struct device *dev)
3285{
3286 struct kobject *kobj;
3287
3288 if (dev->class)
3289 kobj = dev->class->dev_kobj;
3290 else
3291 kobj = sysfs_dev_char_kobj;
3292
3293 return kobj;
3294}
3295
3296static int device_create_sys_dev_entry(struct device *dev)
3297{
3298 struct kobject *kobj = device_to_dev_kobj(dev);
3299 int error = 0;
3300 char devt_str[15];
3301
3302 if (kobj) {
3303 format_dev_t(devt_str, dev->devt);
3304 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3305 }
3306
3307 return error;
3308}
3309
3310static void device_remove_sys_dev_entry(struct device *dev)
3311{
3312 struct kobject *kobj = device_to_dev_kobj(dev);
3313 char devt_str[15];
3314
3315 if (kobj) {
3316 format_dev_t(devt_str, dev->devt);
3317 sysfs_remove_link(kobj, devt_str);
3318 }
3319}
3320
3321static int device_private_init(struct device *dev)
3322{
3323 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3324 if (!dev->p)
3325 return -ENOMEM;
3326 dev->p->device = dev;
3327 klist_init(&dev->p->klist_children, klist_children_get,
3328 klist_children_put);
3329 INIT_LIST_HEAD(&dev->p->deferred_probe);
3330 return 0;
3331}
3332
3333/**
3334 * device_add - add device to device hierarchy.
3335 * @dev: device.
3336 *
3337 * This is part 2 of device_register(), though may be called
3338 * separately _iff_ device_initialize() has been called separately.
3339 *
3340 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3341 * to the global and sibling lists for the device, then
3342 * adds it to the other relevant subsystems of the driver model.
3343 *
3344 * Do not call this routine or device_register() more than once for
3345 * any device structure. The driver model core is not designed to work
3346 * with devices that get unregistered and then spring back to life.
3347 * (Among other things, it's very hard to guarantee that all references
3348 * to the previous incarnation of @dev have been dropped.) Allocate
3349 * and register a fresh new struct device instead.
3350 *
3351 * NOTE: _Never_ directly free @dev after calling this function, even
3352 * if it returned an error! Always use put_device() to give up your
3353 * reference instead.
3354 *
3355 * Rule of thumb is: if device_add() succeeds, you should call
3356 * device_del() when you want to get rid of it. If device_add() has
3357 * *not* succeeded, use *only* put_device() to drop the reference
3358 * count.
3359 */
3360int device_add(struct device *dev)
3361{
3362 struct device *parent;
3363 struct kobject *kobj;
3364 struct class_interface *class_intf;
3365 int error = -EINVAL;
3366 struct kobject *glue_dir = NULL;
3367
3368 dev = get_device(dev);
3369 if (!dev)
3370 goto done;
3371
3372 if (!dev->p) {
3373 error = device_private_init(dev);
3374 if (error)
3375 goto done;
3376 }
3377
3378 /*
3379 * for statically allocated devices, which should all be converted
3380 * some day, we need to initialize the name. We prevent reading back
3381 * the name, and force the use of dev_name()
3382 */
3383 if (dev->init_name) {
3384 dev_set_name(dev, "%s", dev->init_name);
3385 dev->init_name = NULL;
3386 }
3387
3388 /* subsystems can specify simple device enumeration */
3389 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
3390 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3391
3392 if (!dev_name(dev)) {
3393 error = -EINVAL;
3394 goto name_error;
3395 }
3396
3397 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3398
3399 parent = get_device(dev->parent);
3400 kobj = get_device_parent(dev, parent);
3401 if (IS_ERR(kobj)) {
3402 error = PTR_ERR(kobj);
3403 goto parent_error;
3404 }
3405 if (kobj)
3406 dev->kobj.parent = kobj;
3407
3408 /* use parent numa_node */
3409 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3410 set_dev_node(dev, dev_to_node(parent));
3411
3412 /* first, register with generic layer. */
3413 /* we require the name to be set before, and pass NULL */
3414 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3415 if (error) {
3416 glue_dir = get_glue_dir(dev);
3417 goto Error;
3418 }
3419
3420 /* notify platform of device entry */
3421 device_platform_notify(dev);
3422
3423 error = device_create_file(dev, &dev_attr_uevent);
3424 if (error)
3425 goto attrError;
3426
3427 error = device_add_class_symlinks(dev);
3428 if (error)
3429 goto SymlinkError;
3430 error = device_add_attrs(dev);
3431 if (error)
3432 goto AttrsError;
3433 error = bus_add_device(dev);
3434 if (error)
3435 goto BusError;
3436 error = dpm_sysfs_add(dev);
3437 if (error)
3438 goto DPMError;
3439 device_pm_add(dev);
3440
3441 if (MAJOR(dev->devt)) {
3442 error = device_create_file(dev, &dev_attr_dev);
3443 if (error)
3444 goto DevAttrError;
3445
3446 error = device_create_sys_dev_entry(dev);
3447 if (error)
3448 goto SysEntryError;
3449
3450 devtmpfs_create_node(dev);
3451 }
3452
3453 /* Notify clients of device addition. This call must come
3454 * after dpm_sysfs_add() and before kobject_uevent().
3455 */
3456 if (dev->bus)
3457 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3458 BUS_NOTIFY_ADD_DEVICE, dev);
3459
3460 kobject_uevent(&dev->kobj, KOBJ_ADD);
3461
3462 /*
3463 * Check if any of the other devices (consumers) have been waiting for
3464 * this device (supplier) to be added so that they can create a device
3465 * link to it.
3466 *
3467 * This needs to happen after device_pm_add() because device_link_add()
3468 * requires the supplier be registered before it's called.
3469 *
3470 * But this also needs to happen before bus_probe_device() to make sure
3471 * waiting consumers can link to it before the driver is bound to the
3472 * device and the driver sync_state callback is called for this device.
3473 */
3474 if (dev->fwnode && !dev->fwnode->dev) {
3475 dev->fwnode->dev = dev;
3476 fw_devlink_link_device(dev);
3477 }
3478
3479 bus_probe_device(dev);
3480
3481 /*
3482 * If all driver registration is done and a newly added device doesn't
3483 * match with any driver, don't block its consumers from probing in
3484 * case the consumer device is able to operate without this supplier.
3485 */
3486 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3487 fw_devlink_unblock_consumers(dev);
3488
3489 if (parent)
3490 klist_add_tail(&dev->p->knode_parent,
3491 &parent->p->klist_children);
3492
3493 if (dev->class) {
3494 mutex_lock(&dev->class->p->mutex);
3495 /* tie the class to the device */
3496 klist_add_tail(&dev->p->knode_class,
3497 &dev->class->p->klist_devices);
3498
3499 /* notify any interfaces that the device is here */
3500 list_for_each_entry(class_intf,
3501 &dev->class->p->interfaces, node)
3502 if (class_intf->add_dev)
3503 class_intf->add_dev(dev, class_intf);
3504 mutex_unlock(&dev->class->p->mutex);
3505 }
3506done:
3507 put_device(dev);
3508 return error;
3509 SysEntryError:
3510 if (MAJOR(dev->devt))
3511 device_remove_file(dev, &dev_attr_dev);
3512 DevAttrError:
3513 device_pm_remove(dev);
3514 dpm_sysfs_remove(dev);
3515 DPMError:
3516 bus_remove_device(dev);
3517 BusError:
3518 device_remove_attrs(dev);
3519 AttrsError:
3520 device_remove_class_symlinks(dev);
3521 SymlinkError:
3522 device_remove_file(dev, &dev_attr_uevent);
3523 attrError:
3524 device_platform_notify_remove(dev);
3525 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3526 glue_dir = get_glue_dir(dev);
3527 kobject_del(&dev->kobj);
3528 Error:
3529 cleanup_glue_dir(dev, glue_dir);
3530parent_error:
3531 put_device(parent);
3532name_error:
3533 kfree(dev->p);
3534 dev->p = NULL;
3535 goto done;
3536}
3537EXPORT_SYMBOL_GPL(device_add);
3538
3539/**
3540 * device_register - register a device with the system.
3541 * @dev: pointer to the device structure
3542 *
3543 * This happens in two clean steps - initialize the device
3544 * and add it to the system. The two steps can be called
3545 * separately, but this is the easiest and most common.
3546 * I.e. you should only call the two helpers separately if
3547 * have a clearly defined need to use and refcount the device
3548 * before it is added to the hierarchy.
3549 *
3550 * For more information, see the kerneldoc for device_initialize()
3551 * and device_add().
3552 *
3553 * NOTE: _Never_ directly free @dev after calling this function, even
3554 * if it returned an error! Always use put_device() to give up the
3555 * reference initialized in this function instead.
3556 */
3557int device_register(struct device *dev)
3558{
3559 device_initialize(dev);
3560 return device_add(dev);
3561}
3562EXPORT_SYMBOL_GPL(device_register);
3563
3564/**
3565 * get_device - increment reference count for device.
3566 * @dev: device.
3567 *
3568 * This simply forwards the call to kobject_get(), though
3569 * we do take care to provide for the case that we get a NULL
3570 * pointer passed in.
3571 */
3572struct device *get_device(struct device *dev)
3573{
3574 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3575}
3576EXPORT_SYMBOL_GPL(get_device);
3577
3578/**
3579 * put_device - decrement reference count.
3580 * @dev: device in question.
3581 */
3582void put_device(struct device *dev)
3583{
3584 /* might_sleep(); */
3585 if (dev)
3586 kobject_put(&dev->kobj);
3587}
3588EXPORT_SYMBOL_GPL(put_device);
3589
3590bool kill_device(struct device *dev)
3591{
3592 /*
3593 * Require the device lock and set the "dead" flag to guarantee that
3594 * the update behavior is consistent with the other bitfields near
3595 * it and that we cannot have an asynchronous probe routine trying
3596 * to run while we are tearing out the bus/class/sysfs from
3597 * underneath the device.
3598 */
3599 device_lock_assert(dev);
3600
3601 if (dev->p->dead)
3602 return false;
3603 dev->p->dead = true;
3604 return true;
3605}
3606EXPORT_SYMBOL_GPL(kill_device);
3607
3608/**
3609 * device_del - delete device from system.
3610 * @dev: device.
3611 *
3612 * This is the first part of the device unregistration
3613 * sequence. This removes the device from the lists we control
3614 * from here, has it removed from the other driver model
3615 * subsystems it was added to in device_add(), and removes it
3616 * from the kobject hierarchy.
3617 *
3618 * NOTE: this should be called manually _iff_ device_add() was
3619 * also called manually.
3620 */
3621void device_del(struct device *dev)
3622{
3623 struct device *parent = dev->parent;
3624 struct kobject *glue_dir = NULL;
3625 struct class_interface *class_intf;
3626 unsigned int noio_flag;
3627
3628 device_lock(dev);
3629 kill_device(dev);
3630 device_unlock(dev);
3631
3632 if (dev->fwnode && dev->fwnode->dev == dev)
3633 dev->fwnode->dev = NULL;
3634
3635 /* Notify clients of device removal. This call must come
3636 * before dpm_sysfs_remove().
3637 */
3638 noio_flag = memalloc_noio_save();
3639 if (dev->bus)
3640 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3641 BUS_NOTIFY_DEL_DEVICE, dev);
3642
3643 dpm_sysfs_remove(dev);
3644 if (parent)
3645 klist_del(&dev->p->knode_parent);
3646 if (MAJOR(dev->devt)) {
3647 devtmpfs_delete_node(dev);
3648 device_remove_sys_dev_entry(dev);
3649 device_remove_file(dev, &dev_attr_dev);
3650 }
3651 if (dev->class) {
3652 device_remove_class_symlinks(dev);
3653
3654 mutex_lock(&dev->class->p->mutex);
3655 /* notify any interfaces that the device is now gone */
3656 list_for_each_entry(class_intf,
3657 &dev->class->p->interfaces, node)
3658 if (class_intf->remove_dev)
3659 class_intf->remove_dev(dev, class_intf);
3660 /* remove the device from the class list */
3661 klist_del(&dev->p->knode_class);
3662 mutex_unlock(&dev->class->p->mutex);
3663 }
3664 device_remove_file(dev, &dev_attr_uevent);
3665 device_remove_attrs(dev);
3666 bus_remove_device(dev);
3667 device_pm_remove(dev);
3668 driver_deferred_probe_del(dev);
3669 device_platform_notify_remove(dev);
3670 device_links_purge(dev);
3671
3672 if (dev->bus)
3673 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3674 BUS_NOTIFY_REMOVED_DEVICE, dev);
3675 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3676 glue_dir = get_glue_dir(dev);
3677 kobject_del(&dev->kobj);
3678 cleanup_glue_dir(dev, glue_dir);
3679 memalloc_noio_restore(noio_flag);
3680 put_device(parent);
3681}
3682EXPORT_SYMBOL_GPL(device_del);
3683
3684/**
3685 * device_unregister - unregister device from system.
3686 * @dev: device going away.
3687 *
3688 * We do this in two parts, like we do device_register(). First,
3689 * we remove it from all the subsystems with device_del(), then
3690 * we decrement the reference count via put_device(). If that
3691 * is the final reference count, the device will be cleaned up
3692 * via device_release() above. Otherwise, the structure will
3693 * stick around until the final reference to the device is dropped.
3694 */
3695void device_unregister(struct device *dev)
3696{
3697 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3698 device_del(dev);
3699 put_device(dev);
3700}
3701EXPORT_SYMBOL_GPL(device_unregister);
3702
3703static struct device *prev_device(struct klist_iter *i)
3704{
3705 struct klist_node *n = klist_prev(i);
3706 struct device *dev = NULL;
3707 struct device_private *p;
3708
3709 if (n) {
3710 p = to_device_private_parent(n);
3711 dev = p->device;
3712 }
3713 return dev;
3714}
3715
3716static struct device *next_device(struct klist_iter *i)
3717{
3718 struct klist_node *n = klist_next(i);
3719 struct device *dev = NULL;
3720 struct device_private *p;
3721
3722 if (n) {
3723 p = to_device_private_parent(n);
3724 dev = p->device;
3725 }
3726 return dev;
3727}
3728
3729/**
3730 * device_get_devnode - path of device node file
3731 * @dev: device
3732 * @mode: returned file access mode
3733 * @uid: returned file owner
3734 * @gid: returned file group
3735 * @tmp: possibly allocated string
3736 *
3737 * Return the relative path of a possible device node.
3738 * Non-default names may need to allocate a memory to compose
3739 * a name. This memory is returned in tmp and needs to be
3740 * freed by the caller.
3741 */
3742const char *device_get_devnode(struct device *dev,
3743 umode_t *mode, kuid_t *uid, kgid_t *gid,
3744 const char **tmp)
3745{
3746 char *s;
3747
3748 *tmp = NULL;
3749
3750 /* the device type may provide a specific name */
3751 if (dev->type && dev->type->devnode)
3752 *tmp = dev->type->devnode(dev, mode, uid, gid);
3753 if (*tmp)
3754 return *tmp;
3755
3756 /* the class may provide a specific name */
3757 if (dev->class && dev->class->devnode)
3758 *tmp = dev->class->devnode(dev, mode);
3759 if (*tmp)
3760 return *tmp;
3761
3762 /* return name without allocation, tmp == NULL */
3763 if (strchr(dev_name(dev), '!') == NULL)
3764 return dev_name(dev);
3765
3766 /* replace '!' in the name with '/' */
3767 s = kstrdup(dev_name(dev), GFP_KERNEL);
3768 if (!s)
3769 return NULL;
3770 strreplace(s, '!', '/');
3771 return *tmp = s;
3772}
3773
3774/**
3775 * device_for_each_child - device child iterator.
3776 * @parent: parent struct device.
3777 * @fn: function to be called for each device.
3778 * @data: data for the callback.
3779 *
3780 * Iterate over @parent's child devices, and call @fn for each,
3781 * passing it @data.
3782 *
3783 * We check the return of @fn each time. If it returns anything
3784 * other than 0, we break out and return that value.
3785 */
3786int device_for_each_child(struct device *parent, void *data,
3787 int (*fn)(struct device *dev, void *data))
3788{
3789 struct klist_iter i;
3790 struct device *child;
3791 int error = 0;
3792
3793 if (!parent->p)
3794 return 0;
3795
3796 klist_iter_init(&parent->p->klist_children, &i);
3797 while (!error && (child = next_device(&i)))
3798 error = fn(child, data);
3799 klist_iter_exit(&i);
3800 return error;
3801}
3802EXPORT_SYMBOL_GPL(device_for_each_child);
3803
3804/**
3805 * device_for_each_child_reverse - device child iterator in reversed order.
3806 * @parent: parent struct device.
3807 * @fn: function to be called for each device.
3808 * @data: data for the callback.
3809 *
3810 * Iterate over @parent's child devices, and call @fn for each,
3811 * passing it @data.
3812 *
3813 * We check the return of @fn each time. If it returns anything
3814 * other than 0, we break out and return that value.
3815 */
3816int device_for_each_child_reverse(struct device *parent, void *data,
3817 int (*fn)(struct device *dev, void *data))
3818{
3819 struct klist_iter i;
3820 struct device *child;
3821 int error = 0;
3822
3823 if (!parent->p)
3824 return 0;
3825
3826 klist_iter_init(&parent->p->klist_children, &i);
3827 while ((child = prev_device(&i)) && !error)
3828 error = fn(child, data);
3829 klist_iter_exit(&i);
3830 return error;
3831}
3832EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3833
3834/**
3835 * device_find_child - device iterator for locating a particular device.
3836 * @parent: parent struct device
3837 * @match: Callback function to check device
3838 * @data: Data to pass to match function
3839 *
3840 * This is similar to the device_for_each_child() function above, but it
3841 * returns a reference to a device that is 'found' for later use, as
3842 * determined by the @match callback.
3843 *
3844 * The callback should return 0 if the device doesn't match and non-zero
3845 * if it does. If the callback returns non-zero and a reference to the
3846 * current device can be obtained, this function will return to the caller
3847 * and not iterate over any more devices.
3848 *
3849 * NOTE: you will need to drop the reference with put_device() after use.
3850 */
3851struct device *device_find_child(struct device *parent, void *data,
3852 int (*match)(struct device *dev, void *data))
3853{
3854 struct klist_iter i;
3855 struct device *child;
3856
3857 if (!parent)
3858 return NULL;
3859
3860 klist_iter_init(&parent->p->klist_children, &i);
3861 while ((child = next_device(&i)))
3862 if (match(child, data) && get_device(child))
3863 break;
3864 klist_iter_exit(&i);
3865 return child;
3866}
3867EXPORT_SYMBOL_GPL(device_find_child);
3868
3869/**
3870 * device_find_child_by_name - device iterator for locating a child device.
3871 * @parent: parent struct device
3872 * @name: name of the child device
3873 *
3874 * This is similar to the device_find_child() function above, but it
3875 * returns a reference to a device that has the name @name.
3876 *
3877 * NOTE: you will need to drop the reference with put_device() after use.
3878 */
3879struct device *device_find_child_by_name(struct device *parent,
3880 const char *name)
3881{
3882 struct klist_iter i;
3883 struct device *child;
3884
3885 if (!parent)
3886 return NULL;
3887
3888 klist_iter_init(&parent->p->klist_children, &i);
3889 while ((child = next_device(&i)))
3890 if (sysfs_streq(dev_name(child), name) && get_device(child))
3891 break;
3892 klist_iter_exit(&i);
3893 return child;
3894}
3895EXPORT_SYMBOL_GPL(device_find_child_by_name);
3896
3897static int match_any(struct device *dev, void *unused)
3898{
3899 return 1;
3900}
3901
3902/**
3903 * device_find_any_child - device iterator for locating a child device, if any.
3904 * @parent: parent struct device
3905 *
3906 * This is similar to the device_find_child() function above, but it
3907 * returns a reference to a child device, if any.
3908 *
3909 * NOTE: you will need to drop the reference with put_device() after use.
3910 */
3911struct device *device_find_any_child(struct device *parent)
3912{
3913 return device_find_child(parent, NULL, match_any);
3914}
3915EXPORT_SYMBOL_GPL(device_find_any_child);
3916
3917int __init devices_init(void)
3918{
3919 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3920 if (!devices_kset)
3921 return -ENOMEM;
3922 dev_kobj = kobject_create_and_add("dev", NULL);
3923 if (!dev_kobj)
3924 goto dev_kobj_err;
3925 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3926 if (!sysfs_dev_block_kobj)
3927 goto block_kobj_err;
3928 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3929 if (!sysfs_dev_char_kobj)
3930 goto char_kobj_err;
3931
3932 return 0;
3933
3934 char_kobj_err:
3935 kobject_put(sysfs_dev_block_kobj);
3936 block_kobj_err:
3937 kobject_put(dev_kobj);
3938 dev_kobj_err:
3939 kset_unregister(devices_kset);
3940 return -ENOMEM;
3941}
3942
3943static int device_check_offline(struct device *dev, void *not_used)
3944{
3945 int ret;
3946
3947 ret = device_for_each_child(dev, NULL, device_check_offline);
3948 if (ret)
3949 return ret;
3950
3951 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3952}
3953
3954/**
3955 * device_offline - Prepare the device for hot-removal.
3956 * @dev: Device to be put offline.
3957 *
3958 * Execute the device bus type's .offline() callback, if present, to prepare
3959 * the device for a subsequent hot-removal. If that succeeds, the device must
3960 * not be used until either it is removed or its bus type's .online() callback
3961 * is executed.
3962 *
3963 * Call under device_hotplug_lock.
3964 */
3965int device_offline(struct device *dev)
3966{
3967 int ret;
3968
3969 if (dev->offline_disabled)
3970 return -EPERM;
3971
3972 ret = device_for_each_child(dev, NULL, device_check_offline);
3973 if (ret)
3974 return ret;
3975
3976 device_lock(dev);
3977 if (device_supports_offline(dev)) {
3978 if (dev->offline) {
3979 ret = 1;
3980 } else {
3981 ret = dev->bus->offline(dev);
3982 if (!ret) {
3983 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3984 dev->offline = true;
3985 }
3986 }
3987 }
3988 device_unlock(dev);
3989
3990 return ret;
3991}
3992
3993/**
3994 * device_online - Put the device back online after successful device_offline().
3995 * @dev: Device to be put back online.
3996 *
3997 * If device_offline() has been successfully executed for @dev, but the device
3998 * has not been removed subsequently, execute its bus type's .online() callback
3999 * to indicate that the device can be used again.
4000 *
4001 * Call under device_hotplug_lock.
4002 */
4003int device_online(struct device *dev)
4004{
4005 int ret = 0;
4006
4007 device_lock(dev);
4008 if (device_supports_offline(dev)) {
4009 if (dev->offline) {
4010 ret = dev->bus->online(dev);
4011 if (!ret) {
4012 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
4013 dev->offline = false;
4014 }
4015 } else {
4016 ret = 1;
4017 }
4018 }
4019 device_unlock(dev);
4020
4021 return ret;
4022}
4023
4024struct root_device {
4025 struct device dev;
4026 struct module *owner;
4027};
4028
4029static inline struct root_device *to_root_device(struct device *d)
4030{
4031 return container_of(d, struct root_device, dev);
4032}
4033
4034static void root_device_release(struct device *dev)
4035{
4036 kfree(to_root_device(dev));
4037}
4038
4039/**
4040 * __root_device_register - allocate and register a root device
4041 * @name: root device name
4042 * @owner: owner module of the root device, usually THIS_MODULE
4043 *
4044 * This function allocates a root device and registers it
4045 * using device_register(). In order to free the returned
4046 * device, use root_device_unregister().
4047 *
4048 * Root devices are dummy devices which allow other devices
4049 * to be grouped under /sys/devices. Use this function to
4050 * allocate a root device and then use it as the parent of
4051 * any device which should appear under /sys/devices/{name}
4052 *
4053 * The /sys/devices/{name} directory will also contain a
4054 * 'module' symlink which points to the @owner directory
4055 * in sysfs.
4056 *
4057 * Returns &struct device pointer on success, or ERR_PTR() on error.
4058 *
4059 * Note: You probably want to use root_device_register().
4060 */
4061struct device *__root_device_register(const char *name, struct module *owner)
4062{
4063 struct root_device *root;
4064 int err = -ENOMEM;
4065
4066 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
4067 if (!root)
4068 return ERR_PTR(err);
4069
4070 err = dev_set_name(&root->dev, "%s", name);
4071 if (err) {
4072 kfree(root);
4073 return ERR_PTR(err);
4074 }
4075
4076 root->dev.release = root_device_release;
4077
4078 err = device_register(&root->dev);
4079 if (err) {
4080 put_device(&root->dev);
4081 return ERR_PTR(err);
4082 }
4083
4084#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
4085 if (owner) {
4086 struct module_kobject *mk = &owner->mkobj;
4087
4088 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
4089 if (err) {
4090 device_unregister(&root->dev);
4091 return ERR_PTR(err);
4092 }
4093 root->owner = owner;
4094 }
4095#endif
4096
4097 return &root->dev;
4098}
4099EXPORT_SYMBOL_GPL(__root_device_register);
4100
4101/**
4102 * root_device_unregister - unregister and free a root device
4103 * @dev: device going away
4104 *
4105 * This function unregisters and cleans up a device that was created by
4106 * root_device_register().
4107 */
4108void root_device_unregister(struct device *dev)
4109{
4110 struct root_device *root = to_root_device(dev);
4111
4112 if (root->owner)
4113 sysfs_remove_link(&root->dev.kobj, "module");
4114
4115 device_unregister(dev);
4116}
4117EXPORT_SYMBOL_GPL(root_device_unregister);
4118
4119
4120static void device_create_release(struct device *dev)
4121{
4122 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4123 kfree(dev);
4124}
4125
4126static __printf(6, 0) struct device *
4127device_create_groups_vargs(struct class *class, struct device *parent,
4128 dev_t devt, void *drvdata,
4129 const struct attribute_group **groups,
4130 const char *fmt, va_list args)
4131{
4132 struct device *dev = NULL;
4133 int retval = -ENODEV;
4134
4135 if (IS_ERR_OR_NULL(class))
4136 goto error;
4137
4138 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4139 if (!dev) {
4140 retval = -ENOMEM;
4141 goto error;
4142 }
4143
4144 device_initialize(dev);
4145 dev->devt = devt;
4146 dev->class = class;
4147 dev->parent = parent;
4148 dev->groups = groups;
4149 dev->release = device_create_release;
4150 dev_set_drvdata(dev, drvdata);
4151
4152 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4153 if (retval)
4154 goto error;
4155
4156 retval = device_add(dev);
4157 if (retval)
4158 goto error;
4159
4160 return dev;
4161
4162error:
4163 put_device(dev);
4164 return ERR_PTR(retval);
4165}
4166
4167/**
4168 * device_create - creates a device and registers it with sysfs
4169 * @class: pointer to the struct class that this device should be registered to
4170 * @parent: pointer to the parent struct device of this new device, if any
4171 * @devt: the dev_t for the char device to be added
4172 * @drvdata: the data to be added to the device for callbacks
4173 * @fmt: string for the device's name
4174 *
4175 * This function can be used by char device classes. A struct device
4176 * will be created in sysfs, registered to the specified class.
4177 *
4178 * A "dev" file will be created, showing the dev_t for the device, if
4179 * the dev_t is not 0,0.
4180 * If a pointer to a parent struct device is passed in, the newly created
4181 * struct device will be a child of that device in sysfs.
4182 * The pointer to the struct device will be returned from the call.
4183 * Any further sysfs files that might be required can be created using this
4184 * pointer.
4185 *
4186 * Returns &struct device pointer on success, or ERR_PTR() on error.
4187 *
4188 * Note: the struct class passed to this function must have previously
4189 * been created with a call to class_create().
4190 */
4191struct device *device_create(struct class *class, struct device *parent,
4192 dev_t devt, void *drvdata, const char *fmt, ...)
4193{
4194 va_list vargs;
4195 struct device *dev;
4196
4197 va_start(vargs, fmt);
4198 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4199 fmt, vargs);
4200 va_end(vargs);
4201 return dev;
4202}
4203EXPORT_SYMBOL_GPL(device_create);
4204
4205/**
4206 * device_create_with_groups - creates a device and registers it with sysfs
4207 * @class: pointer to the struct class that this device should be registered to
4208 * @parent: pointer to the parent struct device of this new device, if any
4209 * @devt: the dev_t for the char device to be added
4210 * @drvdata: the data to be added to the device for callbacks
4211 * @groups: NULL-terminated list of attribute groups to be created
4212 * @fmt: string for the device's name
4213 *
4214 * This function can be used by char device classes. A struct device
4215 * will be created in sysfs, registered to the specified class.
4216 * Additional attributes specified in the groups parameter will also
4217 * be created automatically.
4218 *
4219 * A "dev" file will be created, showing the dev_t for the device, if
4220 * the dev_t is not 0,0.
4221 * If a pointer to a parent struct device is passed in, the newly created
4222 * struct device will be a child of that device in sysfs.
4223 * The pointer to the struct device will be returned from the call.
4224 * Any further sysfs files that might be required can be created using this
4225 * pointer.
4226 *
4227 * Returns &struct device pointer on success, or ERR_PTR() on error.
4228 *
4229 * Note: the struct class passed to this function must have previously
4230 * been created with a call to class_create().
4231 */
4232struct device *device_create_with_groups(struct class *class,
4233 struct device *parent, dev_t devt,
4234 void *drvdata,
4235 const struct attribute_group **groups,
4236 const char *fmt, ...)
4237{
4238 va_list vargs;
4239 struct device *dev;
4240
4241 va_start(vargs, fmt);
4242 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4243 fmt, vargs);
4244 va_end(vargs);
4245 return dev;
4246}
4247EXPORT_SYMBOL_GPL(device_create_with_groups);
4248
4249/**
4250 * device_destroy - removes a device that was created with device_create()
4251 * @class: pointer to the struct class that this device was registered with
4252 * @devt: the dev_t of the device that was previously registered
4253 *
4254 * This call unregisters and cleans up a device that was created with a
4255 * call to device_create().
4256 */
4257void device_destroy(struct class *class, dev_t devt)
4258{
4259 struct device *dev;
4260
4261 dev = class_find_device_by_devt(class, devt);
4262 if (dev) {
4263 put_device(dev);
4264 device_unregister(dev);
4265 }
4266}
4267EXPORT_SYMBOL_GPL(device_destroy);
4268
4269/**
4270 * device_rename - renames a device
4271 * @dev: the pointer to the struct device to be renamed
4272 * @new_name: the new name of the device
4273 *
4274 * It is the responsibility of the caller to provide mutual
4275 * exclusion between two different calls of device_rename
4276 * on the same device to ensure that new_name is valid and
4277 * won't conflict with other devices.
4278 *
4279 * Note: Don't call this function. Currently, the networking layer calls this
4280 * function, but that will change. The following text from Kay Sievers offers
4281 * some insight:
4282 *
4283 * Renaming devices is racy at many levels, symlinks and other stuff are not
4284 * replaced atomically, and you get a "move" uevent, but it's not easy to
4285 * connect the event to the old and new device. Device nodes are not renamed at
4286 * all, there isn't even support for that in the kernel now.
4287 *
4288 * In the meantime, during renaming, your target name might be taken by another
4289 * driver, creating conflicts. Or the old name is taken directly after you
4290 * renamed it -- then you get events for the same DEVPATH, before you even see
4291 * the "move" event. It's just a mess, and nothing new should ever rely on
4292 * kernel device renaming. Besides that, it's not even implemented now for
4293 * other things than (driver-core wise very simple) network devices.
4294 *
4295 * We are currently about to change network renaming in udev to completely
4296 * disallow renaming of devices in the same namespace as the kernel uses,
4297 * because we can't solve the problems properly, that arise with swapping names
4298 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
4299 * be allowed to some other name than eth[0-9]*, for the aforementioned
4300 * reasons.
4301 *
4302 * Make up a "real" name in the driver before you register anything, or add
4303 * some other attributes for userspace to find the device, or use udev to add
4304 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4305 * don't even want to get into that and try to implement the missing pieces in
4306 * the core. We really have other pieces to fix in the driver core mess. :)
4307 */
4308int device_rename(struct device *dev, const char *new_name)
4309{
4310 struct kobject *kobj = &dev->kobj;
4311 char *old_device_name = NULL;
4312 int error;
4313
4314 dev = get_device(dev);
4315 if (!dev)
4316 return -EINVAL;
4317
4318 dev_dbg(dev, "renaming to %s\n", new_name);
4319
4320 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4321 if (!old_device_name) {
4322 error = -ENOMEM;
4323 goto out;
4324 }
4325
4326 if (dev->class) {
4327 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
4328 kobj, old_device_name,
4329 new_name, kobject_namespace(kobj));
4330 if (error)
4331 goto out;
4332 }
4333
4334 error = kobject_rename(kobj, new_name);
4335 if (error)
4336 goto out;
4337
4338out:
4339 put_device(dev);
4340
4341 kfree(old_device_name);
4342
4343 return error;
4344}
4345EXPORT_SYMBOL_GPL(device_rename);
4346
4347static int device_move_class_links(struct device *dev,
4348 struct device *old_parent,
4349 struct device *new_parent)
4350{
4351 int error = 0;
4352
4353 if (old_parent)
4354 sysfs_remove_link(&dev->kobj, "device");
4355 if (new_parent)
4356 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4357 "device");
4358 return error;
4359}
4360
4361/**
4362 * device_move - moves a device to a new parent
4363 * @dev: the pointer to the struct device to be moved
4364 * @new_parent: the new parent of the device (can be NULL)
4365 * @dpm_order: how to reorder the dpm_list
4366 */
4367int device_move(struct device *dev, struct device *new_parent,
4368 enum dpm_order dpm_order)
4369{
4370 int error;
4371 struct device *old_parent;
4372 struct kobject *new_parent_kobj;
4373
4374 dev = get_device(dev);
4375 if (!dev)
4376 return -EINVAL;
4377
4378 device_pm_lock();
4379 new_parent = get_device(new_parent);
4380 new_parent_kobj = get_device_parent(dev, new_parent);
4381 if (IS_ERR(new_parent_kobj)) {
4382 error = PTR_ERR(new_parent_kobj);
4383 put_device(new_parent);
4384 goto out;
4385 }
4386
4387 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4388 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4389 error = kobject_move(&dev->kobj, new_parent_kobj);
4390 if (error) {
4391 cleanup_glue_dir(dev, new_parent_kobj);
4392 put_device(new_parent);
4393 goto out;
4394 }
4395 old_parent = dev->parent;
4396 dev->parent = new_parent;
4397 if (old_parent)
4398 klist_remove(&dev->p->knode_parent);
4399 if (new_parent) {
4400 klist_add_tail(&dev->p->knode_parent,
4401 &new_parent->p->klist_children);
4402 set_dev_node(dev, dev_to_node(new_parent));
4403 }
4404
4405 if (dev->class) {
4406 error = device_move_class_links(dev, old_parent, new_parent);
4407 if (error) {
4408 /* We ignore errors on cleanup since we're hosed anyway... */
4409 device_move_class_links(dev, new_parent, old_parent);
4410 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4411 if (new_parent)
4412 klist_remove(&dev->p->knode_parent);
4413 dev->parent = old_parent;
4414 if (old_parent) {
4415 klist_add_tail(&dev->p->knode_parent,
4416 &old_parent->p->klist_children);
4417 set_dev_node(dev, dev_to_node(old_parent));
4418 }
4419 }
4420 cleanup_glue_dir(dev, new_parent_kobj);
4421 put_device(new_parent);
4422 goto out;
4423 }
4424 }
4425 switch (dpm_order) {
4426 case DPM_ORDER_NONE:
4427 break;
4428 case DPM_ORDER_DEV_AFTER_PARENT:
4429 device_pm_move_after(dev, new_parent);
4430 devices_kset_move_after(dev, new_parent);
4431 break;
4432 case DPM_ORDER_PARENT_BEFORE_DEV:
4433 device_pm_move_before(new_parent, dev);
4434 devices_kset_move_before(new_parent, dev);
4435 break;
4436 case DPM_ORDER_DEV_LAST:
4437 device_pm_move_last(dev);
4438 devices_kset_move_last(dev);
4439 break;
4440 }
4441
4442 put_device(old_parent);
4443out:
4444 device_pm_unlock();
4445 put_device(dev);
4446 return error;
4447}
4448EXPORT_SYMBOL_GPL(device_move);
4449
4450static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4451 kgid_t kgid)
4452{
4453 struct kobject *kobj = &dev->kobj;
4454 struct class *class = dev->class;
4455 const struct device_type *type = dev->type;
4456 int error;
4457
4458 if (class) {
4459 /*
4460 * Change the device groups of the device class for @dev to
4461 * @kuid/@kgid.
4462 */
4463 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4464 kgid);
4465 if (error)
4466 return error;
4467 }
4468
4469 if (type) {
4470 /*
4471 * Change the device groups of the device type for @dev to
4472 * @kuid/@kgid.
4473 */
4474 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4475 kgid);
4476 if (error)
4477 return error;
4478 }
4479
4480 /* Change the device groups of @dev to @kuid/@kgid. */
4481 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4482 if (error)
4483 return error;
4484
4485 if (device_supports_offline(dev) && !dev->offline_disabled) {
4486 /* Change online device attributes of @dev to @kuid/@kgid. */
4487 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4488 kuid, kgid);
4489 if (error)
4490 return error;
4491 }
4492
4493 return 0;
4494}
4495
4496/**
4497 * device_change_owner - change the owner of an existing device.
4498 * @dev: device.
4499 * @kuid: new owner's kuid
4500 * @kgid: new owner's kgid
4501 *
4502 * This changes the owner of @dev and its corresponding sysfs entries to
4503 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4504 * core.
4505 *
4506 * Returns 0 on success or error code on failure.
4507 */
4508int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4509{
4510 int error;
4511 struct kobject *kobj = &dev->kobj;
4512
4513 dev = get_device(dev);
4514 if (!dev)
4515 return -EINVAL;
4516
4517 /*
4518 * Change the kobject and the default attributes and groups of the
4519 * ktype associated with it to @kuid/@kgid.
4520 */
4521 error = sysfs_change_owner(kobj, kuid, kgid);
4522 if (error)
4523 goto out;
4524
4525 /*
4526 * Change the uevent file for @dev to the new owner. The uevent file
4527 * was created in a separate step when @dev got added and we mirror
4528 * that step here.
4529 */
4530 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4531 kgid);
4532 if (error)
4533 goto out;
4534
4535 /*
4536 * Change the device groups, the device groups associated with the
4537 * device class, and the groups associated with the device type of @dev
4538 * to @kuid/@kgid.
4539 */
4540 error = device_attrs_change_owner(dev, kuid, kgid);
4541 if (error)
4542 goto out;
4543
4544 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4545 if (error)
4546 goto out;
4547
4548#ifdef CONFIG_BLOCK
4549 if (sysfs_deprecated && dev->class == &block_class)
4550 goto out;
4551#endif
4552
4553 /*
4554 * Change the owner of the symlink located in the class directory of
4555 * the device class associated with @dev which points to the actual
4556 * directory entry for @dev to @kuid/@kgid. This ensures that the
4557 * symlink shows the same permissions as its target.
4558 */
4559 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
4560 dev_name(dev), kuid, kgid);
4561 if (error)
4562 goto out;
4563
4564out:
4565 put_device(dev);
4566 return error;
4567}
4568EXPORT_SYMBOL_GPL(device_change_owner);
4569
4570/**
4571 * device_shutdown - call ->shutdown() on each device to shutdown.
4572 */
4573void device_shutdown(void)
4574{
4575 struct device *dev, *parent;
4576
4577 wait_for_device_probe();
4578 device_block_probing();
4579
4580 cpufreq_suspend();
4581
4582 spin_lock(&devices_kset->list_lock);
4583 /*
4584 * Walk the devices list backward, shutting down each in turn.
4585 * Beware that device unplug events may also start pulling
4586 * devices offline, even as the system is shutting down.
4587 */
4588 while (!list_empty(&devices_kset->list)) {
4589 dev = list_entry(devices_kset->list.prev, struct device,
4590 kobj.entry);
4591
4592 /*
4593 * hold reference count of device's parent to
4594 * prevent it from being freed because parent's
4595 * lock is to be held
4596 */
4597 parent = get_device(dev->parent);
4598 get_device(dev);
4599 /*
4600 * Make sure the device is off the kset list, in the
4601 * event that dev->*->shutdown() doesn't remove it.
4602 */
4603 list_del_init(&dev->kobj.entry);
4604 spin_unlock(&devices_kset->list_lock);
4605
4606 /* hold lock to avoid race with probe/release */
4607 if (parent)
4608 device_lock(parent);
4609 device_lock(dev);
4610
4611 /* Don't allow any more runtime suspends */
4612 pm_runtime_get_noresume(dev);
4613 pm_runtime_barrier(dev);
4614
4615 if (dev->class && dev->class->shutdown_pre) {
4616 if (initcall_debug)
4617 dev_info(dev, "shutdown_pre\n");
4618 dev->class->shutdown_pre(dev);
4619 }
4620 if (dev->bus && dev->bus->shutdown) {
4621 if (initcall_debug)
4622 dev_info(dev, "shutdown\n");
4623 dev->bus->shutdown(dev);
4624 } else if (dev->driver && dev->driver->shutdown) {
4625 if (initcall_debug)
4626 dev_info(dev, "shutdown\n");
4627 dev->driver->shutdown(dev);
4628 }
4629
4630 device_unlock(dev);
4631 if (parent)
4632 device_unlock(parent);
4633
4634 put_device(dev);
4635 put_device(parent);
4636
4637 spin_lock(&devices_kset->list_lock);
4638 }
4639 spin_unlock(&devices_kset->list_lock);
4640}
4641
4642/*
4643 * Device logging functions
4644 */
4645
4646#ifdef CONFIG_PRINTK
4647static void
4648set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4649{
4650 const char *subsys;
4651
4652 memset(dev_info, 0, sizeof(*dev_info));
4653
4654 if (dev->class)
4655 subsys = dev->class->name;
4656 else if (dev->bus)
4657 subsys = dev->bus->name;
4658 else
4659 return;
4660
4661 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4662
4663 /*
4664 * Add device identifier DEVICE=:
4665 * b12:8 block dev_t
4666 * c127:3 char dev_t
4667 * n8 netdev ifindex
4668 * +sound:card0 subsystem:devname
4669 */
4670 if (MAJOR(dev->devt)) {
4671 char c;
4672
4673 if (strcmp(subsys, "block") == 0)
4674 c = 'b';
4675 else
4676 c = 'c';
4677
4678 snprintf(dev_info->device, sizeof(dev_info->device),
4679 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4680 } else if (strcmp(subsys, "net") == 0) {
4681 struct net_device *net = to_net_dev(dev);
4682
4683 snprintf(dev_info->device, sizeof(dev_info->device),
4684 "n%u", net->ifindex);
4685 } else {
4686 snprintf(dev_info->device, sizeof(dev_info->device),
4687 "+%s:%s", subsys, dev_name(dev));
4688 }
4689}
4690
4691int dev_vprintk_emit(int level, const struct device *dev,
4692 const char *fmt, va_list args)
4693{
4694 struct dev_printk_info dev_info;
4695
4696 set_dev_info(dev, &dev_info);
4697
4698 return vprintk_emit(0, level, &dev_info, fmt, args);
4699}
4700EXPORT_SYMBOL(dev_vprintk_emit);
4701
4702int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4703{
4704 va_list args;
4705 int r;
4706
4707 va_start(args, fmt);
4708
4709 r = dev_vprintk_emit(level, dev, fmt, args);
4710
4711 va_end(args);
4712
4713 return r;
4714}
4715EXPORT_SYMBOL(dev_printk_emit);
4716
4717static void __dev_printk(const char *level, const struct device *dev,
4718 struct va_format *vaf)
4719{
4720 if (dev)
4721 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4722 dev_driver_string(dev), dev_name(dev), vaf);
4723 else
4724 printk("%s(NULL device *): %pV", level, vaf);
4725}
4726
4727void _dev_printk(const char *level, const struct device *dev,
4728 const char *fmt, ...)
4729{
4730 struct va_format vaf;
4731 va_list args;
4732
4733 va_start(args, fmt);
4734
4735 vaf.fmt = fmt;
4736 vaf.va = &args;
4737
4738 __dev_printk(level, dev, &vaf);
4739
4740 va_end(args);
4741}
4742EXPORT_SYMBOL(_dev_printk);
4743
4744#define define_dev_printk_level(func, kern_level) \
4745void func(const struct device *dev, const char *fmt, ...) \
4746{ \
4747 struct va_format vaf; \
4748 va_list args; \
4749 \
4750 va_start(args, fmt); \
4751 \
4752 vaf.fmt = fmt; \
4753 vaf.va = &args; \
4754 \
4755 __dev_printk(kern_level, dev, &vaf); \
4756 \
4757 va_end(args); \
4758} \
4759EXPORT_SYMBOL(func);
4760
4761define_dev_printk_level(_dev_emerg, KERN_EMERG);
4762define_dev_printk_level(_dev_alert, KERN_ALERT);
4763define_dev_printk_level(_dev_crit, KERN_CRIT);
4764define_dev_printk_level(_dev_err, KERN_ERR);
4765define_dev_printk_level(_dev_warn, KERN_WARNING);
4766define_dev_printk_level(_dev_notice, KERN_NOTICE);
4767define_dev_printk_level(_dev_info, KERN_INFO);
4768
4769#endif
4770
4771/**
4772 * dev_err_probe - probe error check and log helper
4773 * @dev: the pointer to the struct device
4774 * @err: error value to test
4775 * @fmt: printf-style format string
4776 * @...: arguments as specified in the format string
4777 *
4778 * This helper implements common pattern present in probe functions for error
4779 * checking: print debug or error message depending if the error value is
4780 * -EPROBE_DEFER and propagate error upwards.
4781 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4782 * checked later by reading devices_deferred debugfs attribute.
4783 * It replaces code sequence::
4784 *
4785 * if (err != -EPROBE_DEFER)
4786 * dev_err(dev, ...);
4787 * else
4788 * dev_dbg(dev, ...);
4789 * return err;
4790 *
4791 * with::
4792 *
4793 * return dev_err_probe(dev, err, ...);
4794 *
4795 * Note that it is deemed acceptable to use this function for error
4796 * prints during probe even if the @err is known to never be -EPROBE_DEFER.
4797 * The benefit compared to a normal dev_err() is the standardized format
4798 * of the error code and the fact that the error code is returned.
4799 *
4800 * Returns @err.
4801 *
4802 */
4803int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4804{
4805 struct va_format vaf;
4806 va_list args;
4807
4808 va_start(args, fmt);
4809 vaf.fmt = fmt;
4810 vaf.va = &args;
4811
4812 if (err != -EPROBE_DEFER) {
4813 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4814 } else {
4815 device_set_deferred_probe_reason(dev, &vaf);
4816 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4817 }
4818
4819 va_end(args);
4820
4821 return err;
4822}
4823EXPORT_SYMBOL_GPL(dev_err_probe);
4824
4825static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4826{
4827 return fwnode && !IS_ERR(fwnode->secondary);
4828}
4829
4830/**
4831 * set_primary_fwnode - Change the primary firmware node of a given device.
4832 * @dev: Device to handle.
4833 * @fwnode: New primary firmware node of the device.
4834 *
4835 * Set the device's firmware node pointer to @fwnode, but if a secondary
4836 * firmware node of the device is present, preserve it.
4837 *
4838 * Valid fwnode cases are:
4839 * - primary --> secondary --> -ENODEV
4840 * - primary --> NULL
4841 * - secondary --> -ENODEV
4842 * - NULL
4843 */
4844void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4845{
4846 struct device *parent = dev->parent;
4847 struct fwnode_handle *fn = dev->fwnode;
4848
4849 if (fwnode) {
4850 if (fwnode_is_primary(fn))
4851 fn = fn->secondary;
4852
4853 if (fn) {
4854 WARN_ON(fwnode->secondary);
4855 fwnode->secondary = fn;
4856 }
4857 dev->fwnode = fwnode;
4858 } else {
4859 if (fwnode_is_primary(fn)) {
4860 dev->fwnode = fn->secondary;
4861 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
4862 if (!(parent && fn == parent->fwnode))
4863 fn->secondary = NULL;
4864 } else {
4865 dev->fwnode = NULL;
4866 }
4867 }
4868}
4869EXPORT_SYMBOL_GPL(set_primary_fwnode);
4870
4871/**
4872 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4873 * @dev: Device to handle.
4874 * @fwnode: New secondary firmware node of the device.
4875 *
4876 * If a primary firmware node of the device is present, set its secondary
4877 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4878 * @fwnode.
4879 */
4880void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4881{
4882 if (fwnode)
4883 fwnode->secondary = ERR_PTR(-ENODEV);
4884
4885 if (fwnode_is_primary(dev->fwnode))
4886 dev->fwnode->secondary = fwnode;
4887 else
4888 dev->fwnode = fwnode;
4889}
4890EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4891
4892/**
4893 * device_set_of_node_from_dev - reuse device-tree node of another device
4894 * @dev: device whose device-tree node is being set
4895 * @dev2: device whose device-tree node is being reused
4896 *
4897 * Takes another reference to the new device-tree node after first dropping
4898 * any reference held to the old node.
4899 */
4900void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4901{
4902 of_node_put(dev->of_node);
4903 dev->of_node = of_node_get(dev2->of_node);
4904 dev->of_node_reused = true;
4905}
4906EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4907
4908void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
4909{
4910 dev->fwnode = fwnode;
4911 dev->of_node = to_of_node(fwnode);
4912}
4913EXPORT_SYMBOL_GPL(device_set_node);
4914
4915int device_match_name(struct device *dev, const void *name)
4916{
4917 return sysfs_streq(dev_name(dev), name);
4918}
4919EXPORT_SYMBOL_GPL(device_match_name);
4920
4921int device_match_of_node(struct device *dev, const void *np)
4922{
4923 return dev->of_node == np;
4924}
4925EXPORT_SYMBOL_GPL(device_match_of_node);
4926
4927int device_match_fwnode(struct device *dev, const void *fwnode)
4928{
4929 return dev_fwnode(dev) == fwnode;
4930}
4931EXPORT_SYMBOL_GPL(device_match_fwnode);
4932
4933int device_match_devt(struct device *dev, const void *pdevt)
4934{
4935 return dev->devt == *(dev_t *)pdevt;
4936}
4937EXPORT_SYMBOL_GPL(device_match_devt);
4938
4939int device_match_acpi_dev(struct device *dev, const void *adev)
4940{
4941 return ACPI_COMPANION(dev) == adev;
4942}
4943EXPORT_SYMBOL(device_match_acpi_dev);
4944
4945int device_match_acpi_handle(struct device *dev, const void *handle)
4946{
4947 return ACPI_HANDLE(dev) == handle;
4948}
4949EXPORT_SYMBOL(device_match_acpi_handle);
4950
4951int device_match_any(struct device *dev, const void *unused)
4952{
4953 return 1;
4954}
4955EXPORT_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/device.h>
12#include <linux/err.h>
13#include <linux/fwnode.h>
14#include <linux/init.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <linux/string.h>
18#include <linux/kdev_t.h>
19#include <linux/notifier.h>
20#include <linux/of.h>
21#include <linux/of_device.h>
22#include <linux/genhd.h>
23#include <linux/mutex.h>
24#include <linux/pm_runtime.h>
25#include <linux/netdevice.h>
26#include <linux/sched/signal.h>
27#include <linux/sysfs.h>
28
29#include "base.h"
30#include "power/power.h"
31
32#ifdef CONFIG_SYSFS_DEPRECATED
33#ifdef CONFIG_SYSFS_DEPRECATED_V2
34long sysfs_deprecated = 1;
35#else
36long sysfs_deprecated = 0;
37#endif
38static int __init sysfs_deprecated_setup(char *arg)
39{
40 return kstrtol(arg, 10, &sysfs_deprecated);
41}
42early_param("sysfs.deprecated", sysfs_deprecated_setup);
43#endif
44
45/* Device links support. */
46
47#ifdef CONFIG_SRCU
48static DEFINE_MUTEX(device_links_lock);
49DEFINE_STATIC_SRCU(device_links_srcu);
50
51static inline void device_links_write_lock(void)
52{
53 mutex_lock(&device_links_lock);
54}
55
56static inline void device_links_write_unlock(void)
57{
58 mutex_unlock(&device_links_lock);
59}
60
61int device_links_read_lock(void)
62{
63 return srcu_read_lock(&device_links_srcu);
64}
65
66void device_links_read_unlock(int idx)
67{
68 srcu_read_unlock(&device_links_srcu, idx);
69}
70#else /* !CONFIG_SRCU */
71static DECLARE_RWSEM(device_links_lock);
72
73static inline void device_links_write_lock(void)
74{
75 down_write(&device_links_lock);
76}
77
78static inline void device_links_write_unlock(void)
79{
80 up_write(&device_links_lock);
81}
82
83int device_links_read_lock(void)
84{
85 down_read(&device_links_lock);
86 return 0;
87}
88
89void device_links_read_unlock(int not_used)
90{
91 up_read(&device_links_lock);
92}
93#endif /* !CONFIG_SRCU */
94
95/**
96 * device_is_dependent - Check if one device depends on another one
97 * @dev: Device to check dependencies for.
98 * @target: Device to check against.
99 *
100 * Check if @target depends on @dev or any device dependent on it (its child or
101 * its consumer etc). Return 1 if that is the case or 0 otherwise.
102 */
103static int device_is_dependent(struct device *dev, void *target)
104{
105 struct device_link *link;
106 int ret;
107
108 if (WARN_ON(dev == target))
109 return 1;
110
111 ret = device_for_each_child(dev, target, device_is_dependent);
112 if (ret)
113 return ret;
114
115 list_for_each_entry(link, &dev->links.consumers, s_node) {
116 if (WARN_ON(link->consumer == target))
117 return 1;
118
119 ret = device_is_dependent(link->consumer, target);
120 if (ret)
121 break;
122 }
123 return ret;
124}
125
126static int device_reorder_to_tail(struct device *dev, void *not_used)
127{
128 struct device_link *link;
129
130 /*
131 * Devices that have not been registered yet will be put to the ends
132 * of the lists during the registration, so skip them here.
133 */
134 if (device_is_registered(dev))
135 devices_kset_move_last(dev);
136
137 if (device_pm_initialized(dev))
138 device_pm_move_last(dev);
139
140 device_for_each_child(dev, NULL, device_reorder_to_tail);
141 list_for_each_entry(link, &dev->links.consumers, s_node)
142 device_reorder_to_tail(link->consumer, NULL);
143
144 return 0;
145}
146
147/**
148 * device_link_add - Create a link between two devices.
149 * @consumer: Consumer end of the link.
150 * @supplier: Supplier end of the link.
151 * @flags: Link flags.
152 *
153 * The caller is responsible for the proper synchronization of the link creation
154 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
155 * runtime PM framework to take the link into account. Second, if the
156 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
157 * be forced into the active metastate and reference-counted upon the creation
158 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
159 * ignored.
160 *
161 * If the DL_FLAG_AUTOREMOVE is set, the link will be removed automatically
162 * when the consumer device driver unbinds from it. The combination of both
163 * DL_FLAG_AUTOREMOVE and DL_FLAG_STATELESS set is invalid and will cause NULL
164 * to be returned.
165 *
166 * A side effect of the link creation is re-ordering of dpm_list and the
167 * devices_kset list by moving the consumer device and all devices depending
168 * on it to the ends of these lists (that does not happen to devices that have
169 * not been registered when this function is called).
170 *
171 * The supplier device is required to be registered when this function is called
172 * and NULL will be returned if that is not the case. The consumer device need
173 * not be registered, however.
174 */
175struct device_link *device_link_add(struct device *consumer,
176 struct device *supplier, u32 flags)
177{
178 struct device_link *link;
179
180 if (!consumer || !supplier ||
181 ((flags & DL_FLAG_STATELESS) && (flags & DL_FLAG_AUTOREMOVE)))
182 return NULL;
183
184 device_links_write_lock();
185 device_pm_lock();
186
187 /*
188 * If the supplier has not been fully registered yet or there is a
189 * reverse dependency between the consumer and the supplier already in
190 * the graph, return NULL.
191 */
192 if (!device_pm_initialized(supplier)
193 || device_is_dependent(consumer, supplier)) {
194 link = NULL;
195 goto out;
196 }
197
198 list_for_each_entry(link, &supplier->links.consumers, s_node)
199 if (link->consumer == consumer) {
200 kref_get(&link->kref);
201 goto out;
202 }
203
204 link = kzalloc(sizeof(*link), GFP_KERNEL);
205 if (!link)
206 goto out;
207
208 if (flags & DL_FLAG_PM_RUNTIME) {
209 if (flags & DL_FLAG_RPM_ACTIVE) {
210 if (pm_runtime_get_sync(supplier) < 0) {
211 pm_runtime_put_noidle(supplier);
212 kfree(link);
213 link = NULL;
214 goto out;
215 }
216 link->rpm_active = true;
217 }
218 pm_runtime_new_link(consumer);
219 }
220 get_device(supplier);
221 link->supplier = supplier;
222 INIT_LIST_HEAD(&link->s_node);
223 get_device(consumer);
224 link->consumer = consumer;
225 INIT_LIST_HEAD(&link->c_node);
226 link->flags = flags;
227 kref_init(&link->kref);
228
229 /* Determine the initial link state. */
230 if (flags & DL_FLAG_STATELESS) {
231 link->status = DL_STATE_NONE;
232 } else {
233 switch (supplier->links.status) {
234 case DL_DEV_DRIVER_BOUND:
235 switch (consumer->links.status) {
236 case DL_DEV_PROBING:
237 /*
238 * Balance the decrementation of the supplier's
239 * runtime PM usage counter after consumer probe
240 * in driver_probe_device().
241 */
242 if (flags & DL_FLAG_PM_RUNTIME)
243 pm_runtime_get_sync(supplier);
244
245 link->status = DL_STATE_CONSUMER_PROBE;
246 break;
247 case DL_DEV_DRIVER_BOUND:
248 link->status = DL_STATE_ACTIVE;
249 break;
250 default:
251 link->status = DL_STATE_AVAILABLE;
252 break;
253 }
254 break;
255 case DL_DEV_UNBINDING:
256 link->status = DL_STATE_SUPPLIER_UNBIND;
257 break;
258 default:
259 link->status = DL_STATE_DORMANT;
260 break;
261 }
262 }
263
264 /*
265 * Move the consumer and all of the devices depending on it to the end
266 * of dpm_list and the devices_kset list.
267 *
268 * It is necessary to hold dpm_list locked throughout all that or else
269 * we may end up suspending with a wrong ordering of it.
270 */
271 device_reorder_to_tail(consumer, NULL);
272
273 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
274 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
275
276 dev_info(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
277
278 out:
279 device_pm_unlock();
280 device_links_write_unlock();
281 return link;
282}
283EXPORT_SYMBOL_GPL(device_link_add);
284
285static void device_link_free(struct device_link *link)
286{
287 put_device(link->consumer);
288 put_device(link->supplier);
289 kfree(link);
290}
291
292#ifdef CONFIG_SRCU
293static void __device_link_free_srcu(struct rcu_head *rhead)
294{
295 device_link_free(container_of(rhead, struct device_link, rcu_head));
296}
297
298static void __device_link_del(struct kref *kref)
299{
300 struct device_link *link = container_of(kref, struct device_link, kref);
301
302 dev_info(link->consumer, "Dropping the link to %s\n",
303 dev_name(link->supplier));
304
305 if (link->flags & DL_FLAG_PM_RUNTIME)
306 pm_runtime_drop_link(link->consumer);
307
308 list_del_rcu(&link->s_node);
309 list_del_rcu(&link->c_node);
310 call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
311}
312#else /* !CONFIG_SRCU */
313static void __device_link_del(struct kref *kref)
314{
315 struct device_link *link = container_of(kref, struct device_link, kref);
316
317 dev_info(link->consumer, "Dropping the link to %s\n",
318 dev_name(link->supplier));
319
320 if (link->flags & DL_FLAG_PM_RUNTIME)
321 pm_runtime_drop_link(link->consumer);
322
323 list_del(&link->s_node);
324 list_del(&link->c_node);
325 device_link_free(link);
326}
327#endif /* !CONFIG_SRCU */
328
329/**
330 * device_link_del - Delete a link between two devices.
331 * @link: Device link to delete.
332 *
333 * The caller must ensure proper synchronization of this function with runtime
334 * PM. If the link was added multiple times, it needs to be deleted as often.
335 * Care is required for hotplugged devices: Their links are purged on removal
336 * and calling device_link_del() is then no longer allowed.
337 */
338void device_link_del(struct device_link *link)
339{
340 device_links_write_lock();
341 device_pm_lock();
342 kref_put(&link->kref, __device_link_del);
343 device_pm_unlock();
344 device_links_write_unlock();
345}
346EXPORT_SYMBOL_GPL(device_link_del);
347
348static void device_links_missing_supplier(struct device *dev)
349{
350 struct device_link *link;
351
352 list_for_each_entry(link, &dev->links.suppliers, c_node)
353 if (link->status == DL_STATE_CONSUMER_PROBE)
354 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
355}
356
357/**
358 * device_links_check_suppliers - Check presence of supplier drivers.
359 * @dev: Consumer device.
360 *
361 * Check links from this device to any suppliers. Walk the list of the device's
362 * links to suppliers and see if all of them are available. If not, simply
363 * return -EPROBE_DEFER.
364 *
365 * We need to guarantee that the supplier will not go away after the check has
366 * been positive here. It only can go away in __device_release_driver() and
367 * that function checks the device's links to consumers. This means we need to
368 * mark the link as "consumer probe in progress" to make the supplier removal
369 * wait for us to complete (or bad things may happen).
370 *
371 * Links with the DL_FLAG_STATELESS flag set are ignored.
372 */
373int device_links_check_suppliers(struct device *dev)
374{
375 struct device_link *link;
376 int ret = 0;
377
378 device_links_write_lock();
379
380 list_for_each_entry(link, &dev->links.suppliers, c_node) {
381 if (link->flags & DL_FLAG_STATELESS)
382 continue;
383
384 if (link->status != DL_STATE_AVAILABLE) {
385 device_links_missing_supplier(dev);
386 ret = -EPROBE_DEFER;
387 break;
388 }
389 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
390 }
391 dev->links.status = DL_DEV_PROBING;
392
393 device_links_write_unlock();
394 return ret;
395}
396
397/**
398 * device_links_driver_bound - Update device links after probing its driver.
399 * @dev: Device to update the links for.
400 *
401 * The probe has been successful, so update links from this device to any
402 * consumers by changing their status to "available".
403 *
404 * Also change the status of @dev's links to suppliers to "active".
405 *
406 * Links with the DL_FLAG_STATELESS flag set are ignored.
407 */
408void device_links_driver_bound(struct device *dev)
409{
410 struct device_link *link;
411
412 device_links_write_lock();
413
414 list_for_each_entry(link, &dev->links.consumers, s_node) {
415 if (link->flags & DL_FLAG_STATELESS)
416 continue;
417
418 WARN_ON(link->status != DL_STATE_DORMANT);
419 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
420 }
421
422 list_for_each_entry(link, &dev->links.suppliers, c_node) {
423 if (link->flags & DL_FLAG_STATELESS)
424 continue;
425
426 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
427 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
428 }
429
430 dev->links.status = DL_DEV_DRIVER_BOUND;
431
432 device_links_write_unlock();
433}
434
435/**
436 * __device_links_no_driver - Update links of a device without a driver.
437 * @dev: Device without a drvier.
438 *
439 * Delete all non-persistent links from this device to any suppliers.
440 *
441 * Persistent links stay around, but their status is changed to "available",
442 * unless they already are in the "supplier unbind in progress" state in which
443 * case they need not be updated.
444 *
445 * Links with the DL_FLAG_STATELESS flag set are ignored.
446 */
447static void __device_links_no_driver(struct device *dev)
448{
449 struct device_link *link, *ln;
450
451 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
452 if (link->flags & DL_FLAG_STATELESS)
453 continue;
454
455 if (link->flags & DL_FLAG_AUTOREMOVE)
456 kref_put(&link->kref, __device_link_del);
457 else if (link->status != DL_STATE_SUPPLIER_UNBIND)
458 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
459 }
460
461 dev->links.status = DL_DEV_NO_DRIVER;
462}
463
464void device_links_no_driver(struct device *dev)
465{
466 device_links_write_lock();
467 __device_links_no_driver(dev);
468 device_links_write_unlock();
469}
470
471/**
472 * device_links_driver_cleanup - Update links after driver removal.
473 * @dev: Device whose driver has just gone away.
474 *
475 * Update links to consumers for @dev by changing their status to "dormant" and
476 * invoke %__device_links_no_driver() to update links to suppliers for it as
477 * appropriate.
478 *
479 * Links with the DL_FLAG_STATELESS flag set are ignored.
480 */
481void device_links_driver_cleanup(struct device *dev)
482{
483 struct device_link *link;
484
485 device_links_write_lock();
486
487 list_for_each_entry(link, &dev->links.consumers, s_node) {
488 if (link->flags & DL_FLAG_STATELESS)
489 continue;
490
491 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE);
492 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
493 WRITE_ONCE(link->status, DL_STATE_DORMANT);
494 }
495
496 __device_links_no_driver(dev);
497
498 device_links_write_unlock();
499}
500
501/**
502 * device_links_busy - Check if there are any busy links to consumers.
503 * @dev: Device to check.
504 *
505 * Check each consumer of the device and return 'true' if its link's status
506 * is one of "consumer probe" or "active" (meaning that the given consumer is
507 * probing right now or its driver is present). Otherwise, change the link
508 * state to "supplier unbind" to prevent the consumer from being probed
509 * successfully going forward.
510 *
511 * Return 'false' if there are no probing or active consumers.
512 *
513 * Links with the DL_FLAG_STATELESS flag set are ignored.
514 */
515bool device_links_busy(struct device *dev)
516{
517 struct device_link *link;
518 bool ret = false;
519
520 device_links_write_lock();
521
522 list_for_each_entry(link, &dev->links.consumers, s_node) {
523 if (link->flags & DL_FLAG_STATELESS)
524 continue;
525
526 if (link->status == DL_STATE_CONSUMER_PROBE
527 || link->status == DL_STATE_ACTIVE) {
528 ret = true;
529 break;
530 }
531 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
532 }
533
534 dev->links.status = DL_DEV_UNBINDING;
535
536 device_links_write_unlock();
537 return ret;
538}
539
540/**
541 * device_links_unbind_consumers - Force unbind consumers of the given device.
542 * @dev: Device to unbind the consumers of.
543 *
544 * Walk the list of links to consumers for @dev and if any of them is in the
545 * "consumer probe" state, wait for all device probes in progress to complete
546 * and start over.
547 *
548 * If that's not the case, change the status of the link to "supplier unbind"
549 * and check if the link was in the "active" state. If so, force the consumer
550 * driver to unbind and start over (the consumer will not re-probe as we have
551 * changed the state of the link already).
552 *
553 * Links with the DL_FLAG_STATELESS flag set are ignored.
554 */
555void device_links_unbind_consumers(struct device *dev)
556{
557 struct device_link *link;
558
559 start:
560 device_links_write_lock();
561
562 list_for_each_entry(link, &dev->links.consumers, s_node) {
563 enum device_link_state status;
564
565 if (link->flags & DL_FLAG_STATELESS)
566 continue;
567
568 status = link->status;
569 if (status == DL_STATE_CONSUMER_PROBE) {
570 device_links_write_unlock();
571
572 wait_for_device_probe();
573 goto start;
574 }
575 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
576 if (status == DL_STATE_ACTIVE) {
577 struct device *consumer = link->consumer;
578
579 get_device(consumer);
580
581 device_links_write_unlock();
582
583 device_release_driver_internal(consumer, NULL,
584 consumer->parent);
585 put_device(consumer);
586 goto start;
587 }
588 }
589
590 device_links_write_unlock();
591}
592
593/**
594 * device_links_purge - Delete existing links to other devices.
595 * @dev: Target device.
596 */
597static void device_links_purge(struct device *dev)
598{
599 struct device_link *link, *ln;
600
601 /*
602 * Delete all of the remaining links from this device to any other
603 * devices (either consumers or suppliers).
604 */
605 device_links_write_lock();
606
607 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
608 WARN_ON(link->status == DL_STATE_ACTIVE);
609 __device_link_del(&link->kref);
610 }
611
612 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
613 WARN_ON(link->status != DL_STATE_DORMANT &&
614 link->status != DL_STATE_NONE);
615 __device_link_del(&link->kref);
616 }
617
618 device_links_write_unlock();
619}
620
621/* Device links support end. */
622
623int (*platform_notify)(struct device *dev) = NULL;
624int (*platform_notify_remove)(struct device *dev) = NULL;
625static struct kobject *dev_kobj;
626struct kobject *sysfs_dev_char_kobj;
627struct kobject *sysfs_dev_block_kobj;
628
629static DEFINE_MUTEX(device_hotplug_lock);
630
631void lock_device_hotplug(void)
632{
633 mutex_lock(&device_hotplug_lock);
634}
635
636void unlock_device_hotplug(void)
637{
638 mutex_unlock(&device_hotplug_lock);
639}
640
641int lock_device_hotplug_sysfs(void)
642{
643 if (mutex_trylock(&device_hotplug_lock))
644 return 0;
645
646 /* Avoid busy looping (5 ms of sleep should do). */
647 msleep(5);
648 return restart_syscall();
649}
650
651#ifdef CONFIG_BLOCK
652static inline int device_is_not_partition(struct device *dev)
653{
654 return !(dev->type == &part_type);
655}
656#else
657static inline int device_is_not_partition(struct device *dev)
658{
659 return 1;
660}
661#endif
662
663/**
664 * dev_driver_string - Return a device's driver name, if at all possible
665 * @dev: struct device to get the name of
666 *
667 * Will return the device's driver's name if it is bound to a device. If
668 * the device is not bound to a driver, it will return the name of the bus
669 * it is attached to. If it is not attached to a bus either, an empty
670 * string will be returned.
671 */
672const char *dev_driver_string(const struct device *dev)
673{
674 struct device_driver *drv;
675
676 /* dev->driver can change to NULL underneath us because of unbinding,
677 * so be careful about accessing it. dev->bus and dev->class should
678 * never change once they are set, so they don't need special care.
679 */
680 drv = READ_ONCE(dev->driver);
681 return drv ? drv->name :
682 (dev->bus ? dev->bus->name :
683 (dev->class ? dev->class->name : ""));
684}
685EXPORT_SYMBOL(dev_driver_string);
686
687#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
688
689static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
690 char *buf)
691{
692 struct device_attribute *dev_attr = to_dev_attr(attr);
693 struct device *dev = kobj_to_dev(kobj);
694 ssize_t ret = -EIO;
695
696 if (dev_attr->show)
697 ret = dev_attr->show(dev, dev_attr, buf);
698 if (ret >= (ssize_t)PAGE_SIZE) {
699 printk("dev_attr_show: %pS returned bad count\n",
700 dev_attr->show);
701 }
702 return ret;
703}
704
705static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
706 const char *buf, size_t count)
707{
708 struct device_attribute *dev_attr = to_dev_attr(attr);
709 struct device *dev = kobj_to_dev(kobj);
710 ssize_t ret = -EIO;
711
712 if (dev_attr->store)
713 ret = dev_attr->store(dev, dev_attr, buf, count);
714 return ret;
715}
716
717static const struct sysfs_ops dev_sysfs_ops = {
718 .show = dev_attr_show,
719 .store = dev_attr_store,
720};
721
722#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
723
724ssize_t device_store_ulong(struct device *dev,
725 struct device_attribute *attr,
726 const char *buf, size_t size)
727{
728 struct dev_ext_attribute *ea = to_ext_attr(attr);
729 char *end;
730 unsigned long new = simple_strtoul(buf, &end, 0);
731 if (end == buf)
732 return -EINVAL;
733 *(unsigned long *)(ea->var) = new;
734 /* Always return full write size even if we didn't consume all */
735 return size;
736}
737EXPORT_SYMBOL_GPL(device_store_ulong);
738
739ssize_t device_show_ulong(struct device *dev,
740 struct device_attribute *attr,
741 char *buf)
742{
743 struct dev_ext_attribute *ea = to_ext_attr(attr);
744 return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
745}
746EXPORT_SYMBOL_GPL(device_show_ulong);
747
748ssize_t device_store_int(struct device *dev,
749 struct device_attribute *attr,
750 const char *buf, size_t size)
751{
752 struct dev_ext_attribute *ea = to_ext_attr(attr);
753 char *end;
754 long new = simple_strtol(buf, &end, 0);
755 if (end == buf || new > INT_MAX || new < INT_MIN)
756 return -EINVAL;
757 *(int *)(ea->var) = new;
758 /* Always return full write size even if we didn't consume all */
759 return size;
760}
761EXPORT_SYMBOL_GPL(device_store_int);
762
763ssize_t device_show_int(struct device *dev,
764 struct device_attribute *attr,
765 char *buf)
766{
767 struct dev_ext_attribute *ea = to_ext_attr(attr);
768
769 return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
770}
771EXPORT_SYMBOL_GPL(device_show_int);
772
773ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
774 const char *buf, size_t size)
775{
776 struct dev_ext_attribute *ea = to_ext_attr(attr);
777
778 if (strtobool(buf, ea->var) < 0)
779 return -EINVAL;
780
781 return size;
782}
783EXPORT_SYMBOL_GPL(device_store_bool);
784
785ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
786 char *buf)
787{
788 struct dev_ext_attribute *ea = to_ext_attr(attr);
789
790 return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
791}
792EXPORT_SYMBOL_GPL(device_show_bool);
793
794/**
795 * device_release - free device structure.
796 * @kobj: device's kobject.
797 *
798 * This is called once the reference count for the object
799 * reaches 0. We forward the call to the device's release
800 * method, which should handle actually freeing the structure.
801 */
802static void device_release(struct kobject *kobj)
803{
804 struct device *dev = kobj_to_dev(kobj);
805 struct device_private *p = dev->p;
806
807 /*
808 * Some platform devices are driven without driver attached
809 * and managed resources may have been acquired. Make sure
810 * all resources are released.
811 *
812 * Drivers still can add resources into device after device
813 * is deleted but alive, so release devres here to avoid
814 * possible memory leak.
815 */
816 devres_release_all(dev);
817
818 if (dev->release)
819 dev->release(dev);
820 else if (dev->type && dev->type->release)
821 dev->type->release(dev);
822 else if (dev->class && dev->class->dev_release)
823 dev->class->dev_release(dev);
824 else
825 WARN(1, KERN_ERR "Device '%s' does not have a release() "
826 "function, it is broken and must be fixed.\n",
827 dev_name(dev));
828 kfree(p);
829}
830
831static const void *device_namespace(struct kobject *kobj)
832{
833 struct device *dev = kobj_to_dev(kobj);
834 const void *ns = NULL;
835
836 if (dev->class && dev->class->ns_type)
837 ns = dev->class->namespace(dev);
838
839 return ns;
840}
841
842static struct kobj_type device_ktype = {
843 .release = device_release,
844 .sysfs_ops = &dev_sysfs_ops,
845 .namespace = device_namespace,
846};
847
848
849static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
850{
851 struct kobj_type *ktype = get_ktype(kobj);
852
853 if (ktype == &device_ktype) {
854 struct device *dev = kobj_to_dev(kobj);
855 if (dev->bus)
856 return 1;
857 if (dev->class)
858 return 1;
859 }
860 return 0;
861}
862
863static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
864{
865 struct device *dev = kobj_to_dev(kobj);
866
867 if (dev->bus)
868 return dev->bus->name;
869 if (dev->class)
870 return dev->class->name;
871 return NULL;
872}
873
874static int dev_uevent(struct kset *kset, struct kobject *kobj,
875 struct kobj_uevent_env *env)
876{
877 struct device *dev = kobj_to_dev(kobj);
878 int retval = 0;
879
880 /* add device node properties if present */
881 if (MAJOR(dev->devt)) {
882 const char *tmp;
883 const char *name;
884 umode_t mode = 0;
885 kuid_t uid = GLOBAL_ROOT_UID;
886 kgid_t gid = GLOBAL_ROOT_GID;
887
888 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
889 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
890 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
891 if (name) {
892 add_uevent_var(env, "DEVNAME=%s", name);
893 if (mode)
894 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
895 if (!uid_eq(uid, GLOBAL_ROOT_UID))
896 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
897 if (!gid_eq(gid, GLOBAL_ROOT_GID))
898 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
899 kfree(tmp);
900 }
901 }
902
903 if (dev->type && dev->type->name)
904 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
905
906 if (dev->driver)
907 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
908
909 /* Add common DT information about the device */
910 of_device_uevent(dev, env);
911
912 /* have the bus specific function add its stuff */
913 if (dev->bus && dev->bus->uevent) {
914 retval = dev->bus->uevent(dev, env);
915 if (retval)
916 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
917 dev_name(dev), __func__, retval);
918 }
919
920 /* have the class specific function add its stuff */
921 if (dev->class && dev->class->dev_uevent) {
922 retval = dev->class->dev_uevent(dev, env);
923 if (retval)
924 pr_debug("device: '%s': %s: class uevent() "
925 "returned %d\n", dev_name(dev),
926 __func__, retval);
927 }
928
929 /* have the device type specific function add its stuff */
930 if (dev->type && dev->type->uevent) {
931 retval = dev->type->uevent(dev, env);
932 if (retval)
933 pr_debug("device: '%s': %s: dev_type uevent() "
934 "returned %d\n", dev_name(dev),
935 __func__, retval);
936 }
937
938 return retval;
939}
940
941static const struct kset_uevent_ops device_uevent_ops = {
942 .filter = dev_uevent_filter,
943 .name = dev_uevent_name,
944 .uevent = dev_uevent,
945};
946
947static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
948 char *buf)
949{
950 struct kobject *top_kobj;
951 struct kset *kset;
952 struct kobj_uevent_env *env = NULL;
953 int i;
954 size_t count = 0;
955 int retval;
956
957 /* search the kset, the device belongs to */
958 top_kobj = &dev->kobj;
959 while (!top_kobj->kset && top_kobj->parent)
960 top_kobj = top_kobj->parent;
961 if (!top_kobj->kset)
962 goto out;
963
964 kset = top_kobj->kset;
965 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
966 goto out;
967
968 /* respect filter */
969 if (kset->uevent_ops && kset->uevent_ops->filter)
970 if (!kset->uevent_ops->filter(kset, &dev->kobj))
971 goto out;
972
973 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
974 if (!env)
975 return -ENOMEM;
976
977 /* let the kset specific function add its keys */
978 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
979 if (retval)
980 goto out;
981
982 /* copy keys to file */
983 for (i = 0; i < env->envp_idx; i++)
984 count += sprintf(&buf[count], "%s\n", env->envp[i]);
985out:
986 kfree(env);
987 return count;
988}
989
990static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
991 const char *buf, size_t count)
992{
993 if (kobject_synth_uevent(&dev->kobj, buf, count))
994 dev_err(dev, "uevent: failed to send synthetic uevent\n");
995
996 return count;
997}
998static DEVICE_ATTR_RW(uevent);
999
1000static ssize_t online_show(struct device *dev, struct device_attribute *attr,
1001 char *buf)
1002{
1003 bool val;
1004
1005 device_lock(dev);
1006 val = !dev->offline;
1007 device_unlock(dev);
1008 return sprintf(buf, "%u\n", val);
1009}
1010
1011static ssize_t online_store(struct device *dev, struct device_attribute *attr,
1012 const char *buf, size_t count)
1013{
1014 bool val;
1015 int ret;
1016
1017 ret = strtobool(buf, &val);
1018 if (ret < 0)
1019 return ret;
1020
1021 ret = lock_device_hotplug_sysfs();
1022 if (ret)
1023 return ret;
1024
1025 ret = val ? device_online(dev) : device_offline(dev);
1026 unlock_device_hotplug();
1027 return ret < 0 ? ret : count;
1028}
1029static DEVICE_ATTR_RW(online);
1030
1031int device_add_groups(struct device *dev, const struct attribute_group **groups)
1032{
1033 return sysfs_create_groups(&dev->kobj, groups);
1034}
1035EXPORT_SYMBOL_GPL(device_add_groups);
1036
1037void device_remove_groups(struct device *dev,
1038 const struct attribute_group **groups)
1039{
1040 sysfs_remove_groups(&dev->kobj, groups);
1041}
1042EXPORT_SYMBOL_GPL(device_remove_groups);
1043
1044union device_attr_group_devres {
1045 const struct attribute_group *group;
1046 const struct attribute_group **groups;
1047};
1048
1049static int devm_attr_group_match(struct device *dev, void *res, void *data)
1050{
1051 return ((union device_attr_group_devres *)res)->group == data;
1052}
1053
1054static void devm_attr_group_remove(struct device *dev, void *res)
1055{
1056 union device_attr_group_devres *devres = res;
1057 const struct attribute_group *group = devres->group;
1058
1059 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
1060 sysfs_remove_group(&dev->kobj, group);
1061}
1062
1063static void devm_attr_groups_remove(struct device *dev, void *res)
1064{
1065 union device_attr_group_devres *devres = res;
1066 const struct attribute_group **groups = devres->groups;
1067
1068 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
1069 sysfs_remove_groups(&dev->kobj, groups);
1070}
1071
1072/**
1073 * devm_device_add_group - given a device, create a managed attribute group
1074 * @dev: The device to create the group for
1075 * @grp: The attribute group to create
1076 *
1077 * This function creates a group for the first time. It will explicitly
1078 * warn and error if any of the attribute files being created already exist.
1079 *
1080 * Returns 0 on success or error code on failure.
1081 */
1082int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
1083{
1084 union device_attr_group_devres *devres;
1085 int error;
1086
1087 devres = devres_alloc(devm_attr_group_remove,
1088 sizeof(*devres), GFP_KERNEL);
1089 if (!devres)
1090 return -ENOMEM;
1091
1092 error = sysfs_create_group(&dev->kobj, grp);
1093 if (error) {
1094 devres_free(devres);
1095 return error;
1096 }
1097
1098 devres->group = grp;
1099 devres_add(dev, devres);
1100 return 0;
1101}
1102EXPORT_SYMBOL_GPL(devm_device_add_group);
1103
1104/**
1105 * devm_device_remove_group: remove a managed group from a device
1106 * @dev: device to remove the group from
1107 * @grp: group to remove
1108 *
1109 * This function removes a group of attributes from a device. The attributes
1110 * previously have to have been created for this group, otherwise it will fail.
1111 */
1112void devm_device_remove_group(struct device *dev,
1113 const struct attribute_group *grp)
1114{
1115 WARN_ON(devres_release(dev, devm_attr_group_remove,
1116 devm_attr_group_match,
1117 /* cast away const */ (void *)grp));
1118}
1119EXPORT_SYMBOL_GPL(devm_device_remove_group);
1120
1121/**
1122 * devm_device_add_groups - create a bunch of managed attribute groups
1123 * @dev: The device to create the group for
1124 * @groups: The attribute groups to create, NULL terminated
1125 *
1126 * This function creates a bunch of managed attribute groups. If an error
1127 * occurs when creating a group, all previously created groups will be
1128 * removed, unwinding everything back to the original state when this
1129 * function was called. It will explicitly warn and error if any of the
1130 * attribute files being created already exist.
1131 *
1132 * Returns 0 on success or error code from sysfs_create_group on failure.
1133 */
1134int devm_device_add_groups(struct device *dev,
1135 const struct attribute_group **groups)
1136{
1137 union device_attr_group_devres *devres;
1138 int error;
1139
1140 devres = devres_alloc(devm_attr_groups_remove,
1141 sizeof(*devres), GFP_KERNEL);
1142 if (!devres)
1143 return -ENOMEM;
1144
1145 error = sysfs_create_groups(&dev->kobj, groups);
1146 if (error) {
1147 devres_free(devres);
1148 return error;
1149 }
1150
1151 devres->groups = groups;
1152 devres_add(dev, devres);
1153 return 0;
1154}
1155EXPORT_SYMBOL_GPL(devm_device_add_groups);
1156
1157/**
1158 * devm_device_remove_groups - remove a list of managed groups
1159 *
1160 * @dev: The device for the groups to be removed from
1161 * @groups: NULL terminated list of groups to be removed
1162 *
1163 * If groups is not NULL, remove the specified groups from the device.
1164 */
1165void devm_device_remove_groups(struct device *dev,
1166 const struct attribute_group **groups)
1167{
1168 WARN_ON(devres_release(dev, devm_attr_groups_remove,
1169 devm_attr_group_match,
1170 /* cast away const */ (void *)groups));
1171}
1172EXPORT_SYMBOL_GPL(devm_device_remove_groups);
1173
1174static int device_add_attrs(struct device *dev)
1175{
1176 struct class *class = dev->class;
1177 const struct device_type *type = dev->type;
1178 int error;
1179
1180 if (class) {
1181 error = device_add_groups(dev, class->dev_groups);
1182 if (error)
1183 return error;
1184 }
1185
1186 if (type) {
1187 error = device_add_groups(dev, type->groups);
1188 if (error)
1189 goto err_remove_class_groups;
1190 }
1191
1192 error = device_add_groups(dev, dev->groups);
1193 if (error)
1194 goto err_remove_type_groups;
1195
1196 if (device_supports_offline(dev) && !dev->offline_disabled) {
1197 error = device_create_file(dev, &dev_attr_online);
1198 if (error)
1199 goto err_remove_dev_groups;
1200 }
1201
1202 return 0;
1203
1204 err_remove_dev_groups:
1205 device_remove_groups(dev, dev->groups);
1206 err_remove_type_groups:
1207 if (type)
1208 device_remove_groups(dev, type->groups);
1209 err_remove_class_groups:
1210 if (class)
1211 device_remove_groups(dev, class->dev_groups);
1212
1213 return error;
1214}
1215
1216static void device_remove_attrs(struct device *dev)
1217{
1218 struct class *class = dev->class;
1219 const struct device_type *type = dev->type;
1220
1221 device_remove_file(dev, &dev_attr_online);
1222 device_remove_groups(dev, dev->groups);
1223
1224 if (type)
1225 device_remove_groups(dev, type->groups);
1226
1227 if (class)
1228 device_remove_groups(dev, class->dev_groups);
1229}
1230
1231static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
1232 char *buf)
1233{
1234 return print_dev_t(buf, dev->devt);
1235}
1236static DEVICE_ATTR_RO(dev);
1237
1238/* /sys/devices/ */
1239struct kset *devices_kset;
1240
1241/**
1242 * devices_kset_move_before - Move device in the devices_kset's list.
1243 * @deva: Device to move.
1244 * @devb: Device @deva should come before.
1245 */
1246static void devices_kset_move_before(struct device *deva, struct device *devb)
1247{
1248 if (!devices_kset)
1249 return;
1250 pr_debug("devices_kset: Moving %s before %s\n",
1251 dev_name(deva), dev_name(devb));
1252 spin_lock(&devices_kset->list_lock);
1253 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
1254 spin_unlock(&devices_kset->list_lock);
1255}
1256
1257/**
1258 * devices_kset_move_after - Move device in the devices_kset's list.
1259 * @deva: Device to move
1260 * @devb: Device @deva should come after.
1261 */
1262static void devices_kset_move_after(struct device *deva, struct device *devb)
1263{
1264 if (!devices_kset)
1265 return;
1266 pr_debug("devices_kset: Moving %s after %s\n",
1267 dev_name(deva), dev_name(devb));
1268 spin_lock(&devices_kset->list_lock);
1269 list_move(&deva->kobj.entry, &devb->kobj.entry);
1270 spin_unlock(&devices_kset->list_lock);
1271}
1272
1273/**
1274 * devices_kset_move_last - move the device to the end of devices_kset's list.
1275 * @dev: device to move
1276 */
1277void devices_kset_move_last(struct device *dev)
1278{
1279 if (!devices_kset)
1280 return;
1281 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
1282 spin_lock(&devices_kset->list_lock);
1283 list_move_tail(&dev->kobj.entry, &devices_kset->list);
1284 spin_unlock(&devices_kset->list_lock);
1285}
1286
1287/**
1288 * device_create_file - create sysfs attribute file for device.
1289 * @dev: device.
1290 * @attr: device attribute descriptor.
1291 */
1292int device_create_file(struct device *dev,
1293 const struct device_attribute *attr)
1294{
1295 int error = 0;
1296
1297 if (dev) {
1298 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
1299 "Attribute %s: write permission without 'store'\n",
1300 attr->attr.name);
1301 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
1302 "Attribute %s: read permission without 'show'\n",
1303 attr->attr.name);
1304 error = sysfs_create_file(&dev->kobj, &attr->attr);
1305 }
1306
1307 return error;
1308}
1309EXPORT_SYMBOL_GPL(device_create_file);
1310
1311/**
1312 * device_remove_file - remove sysfs attribute file.
1313 * @dev: device.
1314 * @attr: device attribute descriptor.
1315 */
1316void device_remove_file(struct device *dev,
1317 const struct device_attribute *attr)
1318{
1319 if (dev)
1320 sysfs_remove_file(&dev->kobj, &attr->attr);
1321}
1322EXPORT_SYMBOL_GPL(device_remove_file);
1323
1324/**
1325 * device_remove_file_self - remove sysfs attribute file from its own method.
1326 * @dev: device.
1327 * @attr: device attribute descriptor.
1328 *
1329 * See kernfs_remove_self() for details.
1330 */
1331bool device_remove_file_self(struct device *dev,
1332 const struct device_attribute *attr)
1333{
1334 if (dev)
1335 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
1336 else
1337 return false;
1338}
1339EXPORT_SYMBOL_GPL(device_remove_file_self);
1340
1341/**
1342 * device_create_bin_file - create sysfs binary attribute file for device.
1343 * @dev: device.
1344 * @attr: device binary attribute descriptor.
1345 */
1346int device_create_bin_file(struct device *dev,
1347 const struct bin_attribute *attr)
1348{
1349 int error = -EINVAL;
1350 if (dev)
1351 error = sysfs_create_bin_file(&dev->kobj, attr);
1352 return error;
1353}
1354EXPORT_SYMBOL_GPL(device_create_bin_file);
1355
1356/**
1357 * device_remove_bin_file - remove sysfs binary attribute file
1358 * @dev: device.
1359 * @attr: device binary attribute descriptor.
1360 */
1361void device_remove_bin_file(struct device *dev,
1362 const struct bin_attribute *attr)
1363{
1364 if (dev)
1365 sysfs_remove_bin_file(&dev->kobj, attr);
1366}
1367EXPORT_SYMBOL_GPL(device_remove_bin_file);
1368
1369static void klist_children_get(struct klist_node *n)
1370{
1371 struct device_private *p = to_device_private_parent(n);
1372 struct device *dev = p->device;
1373
1374 get_device(dev);
1375}
1376
1377static void klist_children_put(struct klist_node *n)
1378{
1379 struct device_private *p = to_device_private_parent(n);
1380 struct device *dev = p->device;
1381
1382 put_device(dev);
1383}
1384
1385/**
1386 * device_initialize - init device structure.
1387 * @dev: device.
1388 *
1389 * This prepares the device for use by other layers by initializing
1390 * its fields.
1391 * It is the first half of device_register(), if called by
1392 * that function, though it can also be called separately, so one
1393 * may use @dev's fields. In particular, get_device()/put_device()
1394 * may be used for reference counting of @dev after calling this
1395 * function.
1396 *
1397 * All fields in @dev must be initialized by the caller to 0, except
1398 * for those explicitly set to some other value. The simplest
1399 * approach is to use kzalloc() to allocate the structure containing
1400 * @dev.
1401 *
1402 * NOTE: Use put_device() to give up your reference instead of freeing
1403 * @dev directly once you have called this function.
1404 */
1405void device_initialize(struct device *dev)
1406{
1407 dev->kobj.kset = devices_kset;
1408 kobject_init(&dev->kobj, &device_ktype);
1409 INIT_LIST_HEAD(&dev->dma_pools);
1410 mutex_init(&dev->mutex);
1411 lockdep_set_novalidate_class(&dev->mutex);
1412 spin_lock_init(&dev->devres_lock);
1413 INIT_LIST_HEAD(&dev->devres_head);
1414 device_pm_init(dev);
1415 set_dev_node(dev, -1);
1416#ifdef CONFIG_GENERIC_MSI_IRQ
1417 INIT_LIST_HEAD(&dev->msi_list);
1418#endif
1419 INIT_LIST_HEAD(&dev->links.consumers);
1420 INIT_LIST_HEAD(&dev->links.suppliers);
1421 dev->links.status = DL_DEV_NO_DRIVER;
1422}
1423EXPORT_SYMBOL_GPL(device_initialize);
1424
1425struct kobject *virtual_device_parent(struct device *dev)
1426{
1427 static struct kobject *virtual_dir = NULL;
1428
1429 if (!virtual_dir)
1430 virtual_dir = kobject_create_and_add("virtual",
1431 &devices_kset->kobj);
1432
1433 return virtual_dir;
1434}
1435
1436struct class_dir {
1437 struct kobject kobj;
1438 struct class *class;
1439};
1440
1441#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
1442
1443static void class_dir_release(struct kobject *kobj)
1444{
1445 struct class_dir *dir = to_class_dir(kobj);
1446 kfree(dir);
1447}
1448
1449static const
1450struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
1451{
1452 struct class_dir *dir = to_class_dir(kobj);
1453 return dir->class->ns_type;
1454}
1455
1456static struct kobj_type class_dir_ktype = {
1457 .release = class_dir_release,
1458 .sysfs_ops = &kobj_sysfs_ops,
1459 .child_ns_type = class_dir_child_ns_type
1460};
1461
1462static struct kobject *
1463class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
1464{
1465 struct class_dir *dir;
1466 int retval;
1467
1468 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1469 if (!dir)
1470 return NULL;
1471
1472 dir->class = class;
1473 kobject_init(&dir->kobj, &class_dir_ktype);
1474
1475 dir->kobj.kset = &class->p->glue_dirs;
1476
1477 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
1478 if (retval < 0) {
1479 kobject_put(&dir->kobj);
1480 return NULL;
1481 }
1482 return &dir->kobj;
1483}
1484
1485static DEFINE_MUTEX(gdp_mutex);
1486
1487static struct kobject *get_device_parent(struct device *dev,
1488 struct device *parent)
1489{
1490 if (dev->class) {
1491 struct kobject *kobj = NULL;
1492 struct kobject *parent_kobj;
1493 struct kobject *k;
1494
1495#ifdef CONFIG_BLOCK
1496 /* block disks show up in /sys/block */
1497 if (sysfs_deprecated && dev->class == &block_class) {
1498 if (parent && parent->class == &block_class)
1499 return &parent->kobj;
1500 return &block_class.p->subsys.kobj;
1501 }
1502#endif
1503
1504 /*
1505 * If we have no parent, we live in "virtual".
1506 * Class-devices with a non class-device as parent, live
1507 * in a "glue" directory to prevent namespace collisions.
1508 */
1509 if (parent == NULL)
1510 parent_kobj = virtual_device_parent(dev);
1511 else if (parent->class && !dev->class->ns_type)
1512 return &parent->kobj;
1513 else
1514 parent_kobj = &parent->kobj;
1515
1516 mutex_lock(&gdp_mutex);
1517
1518 /* find our class-directory at the parent and reference it */
1519 spin_lock(&dev->class->p->glue_dirs.list_lock);
1520 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
1521 if (k->parent == parent_kobj) {
1522 kobj = kobject_get(k);
1523 break;
1524 }
1525 spin_unlock(&dev->class->p->glue_dirs.list_lock);
1526 if (kobj) {
1527 mutex_unlock(&gdp_mutex);
1528 return kobj;
1529 }
1530
1531 /* or create a new class-directory at the parent device */
1532 k = class_dir_create_and_add(dev->class, parent_kobj);
1533 /* do not emit an uevent for this simple "glue" directory */
1534 mutex_unlock(&gdp_mutex);
1535 return k;
1536 }
1537
1538 /* subsystems can specify a default root directory for their devices */
1539 if (!parent && dev->bus && dev->bus->dev_root)
1540 return &dev->bus->dev_root->kobj;
1541
1542 if (parent)
1543 return &parent->kobj;
1544 return NULL;
1545}
1546
1547static inline bool live_in_glue_dir(struct kobject *kobj,
1548 struct device *dev)
1549{
1550 if (!kobj || !dev->class ||
1551 kobj->kset != &dev->class->p->glue_dirs)
1552 return false;
1553 return true;
1554}
1555
1556static inline struct kobject *get_glue_dir(struct device *dev)
1557{
1558 return dev->kobj.parent;
1559}
1560
1561/*
1562 * make sure cleaning up dir as the last step, we need to make
1563 * sure .release handler of kobject is run with holding the
1564 * global lock
1565 */
1566static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
1567{
1568 /* see if we live in a "glue" directory */
1569 if (!live_in_glue_dir(glue_dir, dev))
1570 return;
1571
1572 mutex_lock(&gdp_mutex);
1573 kobject_put(glue_dir);
1574 mutex_unlock(&gdp_mutex);
1575}
1576
1577static int device_add_class_symlinks(struct device *dev)
1578{
1579 struct device_node *of_node = dev_of_node(dev);
1580 int error;
1581
1582 if (of_node) {
1583 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
1584 if (error)
1585 dev_warn(dev, "Error %d creating of_node link\n",error);
1586 /* An error here doesn't warrant bringing down the device */
1587 }
1588
1589 if (!dev->class)
1590 return 0;
1591
1592 error = sysfs_create_link(&dev->kobj,
1593 &dev->class->p->subsys.kobj,
1594 "subsystem");
1595 if (error)
1596 goto out_devnode;
1597
1598 if (dev->parent && device_is_not_partition(dev)) {
1599 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
1600 "device");
1601 if (error)
1602 goto out_subsys;
1603 }
1604
1605#ifdef CONFIG_BLOCK
1606 /* /sys/block has directories and does not need symlinks */
1607 if (sysfs_deprecated && dev->class == &block_class)
1608 return 0;
1609#endif
1610
1611 /* link in the class directory pointing to the device */
1612 error = sysfs_create_link(&dev->class->p->subsys.kobj,
1613 &dev->kobj, dev_name(dev));
1614 if (error)
1615 goto out_device;
1616
1617 return 0;
1618
1619out_device:
1620 sysfs_remove_link(&dev->kobj, "device");
1621
1622out_subsys:
1623 sysfs_remove_link(&dev->kobj, "subsystem");
1624out_devnode:
1625 sysfs_remove_link(&dev->kobj, "of_node");
1626 return error;
1627}
1628
1629static void device_remove_class_symlinks(struct device *dev)
1630{
1631 if (dev_of_node(dev))
1632 sysfs_remove_link(&dev->kobj, "of_node");
1633
1634 if (!dev->class)
1635 return;
1636
1637 if (dev->parent && device_is_not_partition(dev))
1638 sysfs_remove_link(&dev->kobj, "device");
1639 sysfs_remove_link(&dev->kobj, "subsystem");
1640#ifdef CONFIG_BLOCK
1641 if (sysfs_deprecated && dev->class == &block_class)
1642 return;
1643#endif
1644 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
1645}
1646
1647/**
1648 * dev_set_name - set a device name
1649 * @dev: device
1650 * @fmt: format string for the device's name
1651 */
1652int dev_set_name(struct device *dev, const char *fmt, ...)
1653{
1654 va_list vargs;
1655 int err;
1656
1657 va_start(vargs, fmt);
1658 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
1659 va_end(vargs);
1660 return err;
1661}
1662EXPORT_SYMBOL_GPL(dev_set_name);
1663
1664/**
1665 * device_to_dev_kobj - select a /sys/dev/ directory for the device
1666 * @dev: device
1667 *
1668 * By default we select char/ for new entries. Setting class->dev_obj
1669 * to NULL prevents an entry from being created. class->dev_kobj must
1670 * be set (or cleared) before any devices are registered to the class
1671 * otherwise device_create_sys_dev_entry() and
1672 * device_remove_sys_dev_entry() will disagree about the presence of
1673 * the link.
1674 */
1675static struct kobject *device_to_dev_kobj(struct device *dev)
1676{
1677 struct kobject *kobj;
1678
1679 if (dev->class)
1680 kobj = dev->class->dev_kobj;
1681 else
1682 kobj = sysfs_dev_char_kobj;
1683
1684 return kobj;
1685}
1686
1687static int device_create_sys_dev_entry(struct device *dev)
1688{
1689 struct kobject *kobj = device_to_dev_kobj(dev);
1690 int error = 0;
1691 char devt_str[15];
1692
1693 if (kobj) {
1694 format_dev_t(devt_str, dev->devt);
1695 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
1696 }
1697
1698 return error;
1699}
1700
1701static void device_remove_sys_dev_entry(struct device *dev)
1702{
1703 struct kobject *kobj = device_to_dev_kobj(dev);
1704 char devt_str[15];
1705
1706 if (kobj) {
1707 format_dev_t(devt_str, dev->devt);
1708 sysfs_remove_link(kobj, devt_str);
1709 }
1710}
1711
1712int device_private_init(struct device *dev)
1713{
1714 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
1715 if (!dev->p)
1716 return -ENOMEM;
1717 dev->p->device = dev;
1718 klist_init(&dev->p->klist_children, klist_children_get,
1719 klist_children_put);
1720 INIT_LIST_HEAD(&dev->p->deferred_probe);
1721 return 0;
1722}
1723
1724/**
1725 * device_add - add device to device hierarchy.
1726 * @dev: device.
1727 *
1728 * This is part 2 of device_register(), though may be called
1729 * separately _iff_ device_initialize() has been called separately.
1730 *
1731 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
1732 * to the global and sibling lists for the device, then
1733 * adds it to the other relevant subsystems of the driver model.
1734 *
1735 * Do not call this routine or device_register() more than once for
1736 * any device structure. The driver model core is not designed to work
1737 * with devices that get unregistered and then spring back to life.
1738 * (Among other things, it's very hard to guarantee that all references
1739 * to the previous incarnation of @dev have been dropped.) Allocate
1740 * and register a fresh new struct device instead.
1741 *
1742 * NOTE: _Never_ directly free @dev after calling this function, even
1743 * if it returned an error! Always use put_device() to give up your
1744 * reference instead.
1745 */
1746int device_add(struct device *dev)
1747{
1748 struct device *parent;
1749 struct kobject *kobj;
1750 struct class_interface *class_intf;
1751 int error = -EINVAL;
1752 struct kobject *glue_dir = NULL;
1753
1754 dev = get_device(dev);
1755 if (!dev)
1756 goto done;
1757
1758 if (!dev->p) {
1759 error = device_private_init(dev);
1760 if (error)
1761 goto done;
1762 }
1763
1764 /*
1765 * for statically allocated devices, which should all be converted
1766 * some day, we need to initialize the name. We prevent reading back
1767 * the name, and force the use of dev_name()
1768 */
1769 if (dev->init_name) {
1770 dev_set_name(dev, "%s", dev->init_name);
1771 dev->init_name = NULL;
1772 }
1773
1774 /* subsystems can specify simple device enumeration */
1775 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
1776 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
1777
1778 if (!dev_name(dev)) {
1779 error = -EINVAL;
1780 goto name_error;
1781 }
1782
1783 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1784
1785 parent = get_device(dev->parent);
1786 kobj = get_device_parent(dev, parent);
1787 if (kobj)
1788 dev->kobj.parent = kobj;
1789
1790 /* use parent numa_node */
1791 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
1792 set_dev_node(dev, dev_to_node(parent));
1793
1794 /* first, register with generic layer. */
1795 /* we require the name to be set before, and pass NULL */
1796 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
1797 if (error) {
1798 glue_dir = get_glue_dir(dev);
1799 goto Error;
1800 }
1801
1802 /* notify platform of device entry */
1803 if (platform_notify)
1804 platform_notify(dev);
1805
1806 error = device_create_file(dev, &dev_attr_uevent);
1807 if (error)
1808 goto attrError;
1809
1810 error = device_add_class_symlinks(dev);
1811 if (error)
1812 goto SymlinkError;
1813 error = device_add_attrs(dev);
1814 if (error)
1815 goto AttrsError;
1816 error = bus_add_device(dev);
1817 if (error)
1818 goto BusError;
1819 error = dpm_sysfs_add(dev);
1820 if (error)
1821 goto DPMError;
1822 device_pm_add(dev);
1823
1824 if (MAJOR(dev->devt)) {
1825 error = device_create_file(dev, &dev_attr_dev);
1826 if (error)
1827 goto DevAttrError;
1828
1829 error = device_create_sys_dev_entry(dev);
1830 if (error)
1831 goto SysEntryError;
1832
1833 devtmpfs_create_node(dev);
1834 }
1835
1836 /* Notify clients of device addition. This call must come
1837 * after dpm_sysfs_add() and before kobject_uevent().
1838 */
1839 if (dev->bus)
1840 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1841 BUS_NOTIFY_ADD_DEVICE, dev);
1842
1843 kobject_uevent(&dev->kobj, KOBJ_ADD);
1844 bus_probe_device(dev);
1845 if (parent)
1846 klist_add_tail(&dev->p->knode_parent,
1847 &parent->p->klist_children);
1848
1849 if (dev->class) {
1850 mutex_lock(&dev->class->p->mutex);
1851 /* tie the class to the device */
1852 klist_add_tail(&dev->knode_class,
1853 &dev->class->p->klist_devices);
1854
1855 /* notify any interfaces that the device is here */
1856 list_for_each_entry(class_intf,
1857 &dev->class->p->interfaces, node)
1858 if (class_intf->add_dev)
1859 class_intf->add_dev(dev, class_intf);
1860 mutex_unlock(&dev->class->p->mutex);
1861 }
1862done:
1863 put_device(dev);
1864 return error;
1865 SysEntryError:
1866 if (MAJOR(dev->devt))
1867 device_remove_file(dev, &dev_attr_dev);
1868 DevAttrError:
1869 device_pm_remove(dev);
1870 dpm_sysfs_remove(dev);
1871 DPMError:
1872 bus_remove_device(dev);
1873 BusError:
1874 device_remove_attrs(dev);
1875 AttrsError:
1876 device_remove_class_symlinks(dev);
1877 SymlinkError:
1878 device_remove_file(dev, &dev_attr_uevent);
1879 attrError:
1880 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1881 glue_dir = get_glue_dir(dev);
1882 kobject_del(&dev->kobj);
1883 Error:
1884 cleanup_glue_dir(dev, glue_dir);
1885 put_device(parent);
1886name_error:
1887 kfree(dev->p);
1888 dev->p = NULL;
1889 goto done;
1890}
1891EXPORT_SYMBOL_GPL(device_add);
1892
1893/**
1894 * device_register - register a device with the system.
1895 * @dev: pointer to the device structure
1896 *
1897 * This happens in two clean steps - initialize the device
1898 * and add it to the system. The two steps can be called
1899 * separately, but this is the easiest and most common.
1900 * I.e. you should only call the two helpers separately if
1901 * have a clearly defined need to use and refcount the device
1902 * before it is added to the hierarchy.
1903 *
1904 * For more information, see the kerneldoc for device_initialize()
1905 * and device_add().
1906 *
1907 * NOTE: _Never_ directly free @dev after calling this function, even
1908 * if it returned an error! Always use put_device() to give up the
1909 * reference initialized in this function instead.
1910 */
1911int device_register(struct device *dev)
1912{
1913 device_initialize(dev);
1914 return device_add(dev);
1915}
1916EXPORT_SYMBOL_GPL(device_register);
1917
1918/**
1919 * get_device - increment reference count for device.
1920 * @dev: device.
1921 *
1922 * This simply forwards the call to kobject_get(), though
1923 * we do take care to provide for the case that we get a NULL
1924 * pointer passed in.
1925 */
1926struct device *get_device(struct device *dev)
1927{
1928 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
1929}
1930EXPORT_SYMBOL_GPL(get_device);
1931
1932/**
1933 * put_device - decrement reference count.
1934 * @dev: device in question.
1935 */
1936void put_device(struct device *dev)
1937{
1938 /* might_sleep(); */
1939 if (dev)
1940 kobject_put(&dev->kobj);
1941}
1942EXPORT_SYMBOL_GPL(put_device);
1943
1944/**
1945 * device_del - delete device from system.
1946 * @dev: device.
1947 *
1948 * This is the first part of the device unregistration
1949 * sequence. This removes the device from the lists we control
1950 * from here, has it removed from the other driver model
1951 * subsystems it was added to in device_add(), and removes it
1952 * from the kobject hierarchy.
1953 *
1954 * NOTE: this should be called manually _iff_ device_add() was
1955 * also called manually.
1956 */
1957void device_del(struct device *dev)
1958{
1959 struct device *parent = dev->parent;
1960 struct kobject *glue_dir = NULL;
1961 struct class_interface *class_intf;
1962
1963 /* Notify clients of device removal. This call must come
1964 * before dpm_sysfs_remove().
1965 */
1966 if (dev->bus)
1967 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1968 BUS_NOTIFY_DEL_DEVICE, dev);
1969
1970 dpm_sysfs_remove(dev);
1971 if (parent)
1972 klist_del(&dev->p->knode_parent);
1973 if (MAJOR(dev->devt)) {
1974 devtmpfs_delete_node(dev);
1975 device_remove_sys_dev_entry(dev);
1976 device_remove_file(dev, &dev_attr_dev);
1977 }
1978 if (dev->class) {
1979 device_remove_class_symlinks(dev);
1980
1981 mutex_lock(&dev->class->p->mutex);
1982 /* notify any interfaces that the device is now gone */
1983 list_for_each_entry(class_intf,
1984 &dev->class->p->interfaces, node)
1985 if (class_intf->remove_dev)
1986 class_intf->remove_dev(dev, class_intf);
1987 /* remove the device from the class list */
1988 klist_del(&dev->knode_class);
1989 mutex_unlock(&dev->class->p->mutex);
1990 }
1991 device_remove_file(dev, &dev_attr_uevent);
1992 device_remove_attrs(dev);
1993 bus_remove_device(dev);
1994 device_pm_remove(dev);
1995 driver_deferred_probe_del(dev);
1996 device_remove_properties(dev);
1997 device_links_purge(dev);
1998
1999 /* Notify the platform of the removal, in case they
2000 * need to do anything...
2001 */
2002 if (platform_notify_remove)
2003 platform_notify_remove(dev);
2004 if (dev->bus)
2005 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
2006 BUS_NOTIFY_REMOVED_DEVICE, dev);
2007 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
2008 glue_dir = get_glue_dir(dev);
2009 kobject_del(&dev->kobj);
2010 cleanup_glue_dir(dev, glue_dir);
2011 put_device(parent);
2012}
2013EXPORT_SYMBOL_GPL(device_del);
2014
2015/**
2016 * device_unregister - unregister device from system.
2017 * @dev: device going away.
2018 *
2019 * We do this in two parts, like we do device_register(). First,
2020 * we remove it from all the subsystems with device_del(), then
2021 * we decrement the reference count via put_device(). If that
2022 * is the final reference count, the device will be cleaned up
2023 * via device_release() above. Otherwise, the structure will
2024 * stick around until the final reference to the device is dropped.
2025 */
2026void device_unregister(struct device *dev)
2027{
2028 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
2029 device_del(dev);
2030 put_device(dev);
2031}
2032EXPORT_SYMBOL_GPL(device_unregister);
2033
2034static struct device *prev_device(struct klist_iter *i)
2035{
2036 struct klist_node *n = klist_prev(i);
2037 struct device *dev = NULL;
2038 struct device_private *p;
2039
2040 if (n) {
2041 p = to_device_private_parent(n);
2042 dev = p->device;
2043 }
2044 return dev;
2045}
2046
2047static struct device *next_device(struct klist_iter *i)
2048{
2049 struct klist_node *n = klist_next(i);
2050 struct device *dev = NULL;
2051 struct device_private *p;
2052
2053 if (n) {
2054 p = to_device_private_parent(n);
2055 dev = p->device;
2056 }
2057 return dev;
2058}
2059
2060/**
2061 * device_get_devnode - path of device node file
2062 * @dev: device
2063 * @mode: returned file access mode
2064 * @uid: returned file owner
2065 * @gid: returned file group
2066 * @tmp: possibly allocated string
2067 *
2068 * Return the relative path of a possible device node.
2069 * Non-default names may need to allocate a memory to compose
2070 * a name. This memory is returned in tmp and needs to be
2071 * freed by the caller.
2072 */
2073const char *device_get_devnode(struct device *dev,
2074 umode_t *mode, kuid_t *uid, kgid_t *gid,
2075 const char **tmp)
2076{
2077 char *s;
2078
2079 *tmp = NULL;
2080
2081 /* the device type may provide a specific name */
2082 if (dev->type && dev->type->devnode)
2083 *tmp = dev->type->devnode(dev, mode, uid, gid);
2084 if (*tmp)
2085 return *tmp;
2086
2087 /* the class may provide a specific name */
2088 if (dev->class && dev->class->devnode)
2089 *tmp = dev->class->devnode(dev, mode);
2090 if (*tmp)
2091 return *tmp;
2092
2093 /* return name without allocation, tmp == NULL */
2094 if (strchr(dev_name(dev), '!') == NULL)
2095 return dev_name(dev);
2096
2097 /* replace '!' in the name with '/' */
2098 s = kstrdup(dev_name(dev), GFP_KERNEL);
2099 if (!s)
2100 return NULL;
2101 strreplace(s, '!', '/');
2102 return *tmp = s;
2103}
2104
2105/**
2106 * device_for_each_child - device child iterator.
2107 * @parent: parent struct device.
2108 * @fn: function to be called for each device.
2109 * @data: data for the callback.
2110 *
2111 * Iterate over @parent's child devices, and call @fn for each,
2112 * passing it @data.
2113 *
2114 * We check the return of @fn each time. If it returns anything
2115 * other than 0, we break out and return that value.
2116 */
2117int device_for_each_child(struct device *parent, void *data,
2118 int (*fn)(struct device *dev, void *data))
2119{
2120 struct klist_iter i;
2121 struct device *child;
2122 int error = 0;
2123
2124 if (!parent->p)
2125 return 0;
2126
2127 klist_iter_init(&parent->p->klist_children, &i);
2128 while (!error && (child = next_device(&i)))
2129 error = fn(child, data);
2130 klist_iter_exit(&i);
2131 return error;
2132}
2133EXPORT_SYMBOL_GPL(device_for_each_child);
2134
2135/**
2136 * device_for_each_child_reverse - device child iterator in reversed order.
2137 * @parent: parent struct device.
2138 * @fn: function to be called for each device.
2139 * @data: data for the callback.
2140 *
2141 * Iterate over @parent's child devices, and call @fn for each,
2142 * passing it @data.
2143 *
2144 * We check the return of @fn each time. If it returns anything
2145 * other than 0, we break out and return that value.
2146 */
2147int device_for_each_child_reverse(struct device *parent, void *data,
2148 int (*fn)(struct device *dev, void *data))
2149{
2150 struct klist_iter i;
2151 struct device *child;
2152 int error = 0;
2153
2154 if (!parent->p)
2155 return 0;
2156
2157 klist_iter_init(&parent->p->klist_children, &i);
2158 while ((child = prev_device(&i)) && !error)
2159 error = fn(child, data);
2160 klist_iter_exit(&i);
2161 return error;
2162}
2163EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
2164
2165/**
2166 * device_find_child - device iterator for locating a particular device.
2167 * @parent: parent struct device
2168 * @match: Callback function to check device
2169 * @data: Data to pass to match function
2170 *
2171 * This is similar to the device_for_each_child() function above, but it
2172 * returns a reference to a device that is 'found' for later use, as
2173 * determined by the @match callback.
2174 *
2175 * The callback should return 0 if the device doesn't match and non-zero
2176 * if it does. If the callback returns non-zero and a reference to the
2177 * current device can be obtained, this function will return to the caller
2178 * and not iterate over any more devices.
2179 *
2180 * NOTE: you will need to drop the reference with put_device() after use.
2181 */
2182struct device *device_find_child(struct device *parent, void *data,
2183 int (*match)(struct device *dev, void *data))
2184{
2185 struct klist_iter i;
2186 struct device *child;
2187
2188 if (!parent)
2189 return NULL;
2190
2191 klist_iter_init(&parent->p->klist_children, &i);
2192 while ((child = next_device(&i)))
2193 if (match(child, data) && get_device(child))
2194 break;
2195 klist_iter_exit(&i);
2196 return child;
2197}
2198EXPORT_SYMBOL_GPL(device_find_child);
2199
2200int __init devices_init(void)
2201{
2202 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
2203 if (!devices_kset)
2204 return -ENOMEM;
2205 dev_kobj = kobject_create_and_add("dev", NULL);
2206 if (!dev_kobj)
2207 goto dev_kobj_err;
2208 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
2209 if (!sysfs_dev_block_kobj)
2210 goto block_kobj_err;
2211 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
2212 if (!sysfs_dev_char_kobj)
2213 goto char_kobj_err;
2214
2215 return 0;
2216
2217 char_kobj_err:
2218 kobject_put(sysfs_dev_block_kobj);
2219 block_kobj_err:
2220 kobject_put(dev_kobj);
2221 dev_kobj_err:
2222 kset_unregister(devices_kset);
2223 return -ENOMEM;
2224}
2225
2226static int device_check_offline(struct device *dev, void *not_used)
2227{
2228 int ret;
2229
2230 ret = device_for_each_child(dev, NULL, device_check_offline);
2231 if (ret)
2232 return ret;
2233
2234 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
2235}
2236
2237/**
2238 * device_offline - Prepare the device for hot-removal.
2239 * @dev: Device to be put offline.
2240 *
2241 * Execute the device bus type's .offline() callback, if present, to prepare
2242 * the device for a subsequent hot-removal. If that succeeds, the device must
2243 * not be used until either it is removed or its bus type's .online() callback
2244 * is executed.
2245 *
2246 * Call under device_hotplug_lock.
2247 */
2248int device_offline(struct device *dev)
2249{
2250 int ret;
2251
2252 if (dev->offline_disabled)
2253 return -EPERM;
2254
2255 ret = device_for_each_child(dev, NULL, device_check_offline);
2256 if (ret)
2257 return ret;
2258
2259 device_lock(dev);
2260 if (device_supports_offline(dev)) {
2261 if (dev->offline) {
2262 ret = 1;
2263 } else {
2264 ret = dev->bus->offline(dev);
2265 if (!ret) {
2266 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
2267 dev->offline = true;
2268 }
2269 }
2270 }
2271 device_unlock(dev);
2272
2273 return ret;
2274}
2275
2276/**
2277 * device_online - Put the device back online after successful device_offline().
2278 * @dev: Device to be put back online.
2279 *
2280 * If device_offline() has been successfully executed for @dev, but the device
2281 * has not been removed subsequently, execute its bus type's .online() callback
2282 * to indicate that the device can be used again.
2283 *
2284 * Call under device_hotplug_lock.
2285 */
2286int device_online(struct device *dev)
2287{
2288 int ret = 0;
2289
2290 device_lock(dev);
2291 if (device_supports_offline(dev)) {
2292 if (dev->offline) {
2293 ret = dev->bus->online(dev);
2294 if (!ret) {
2295 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
2296 dev->offline = false;
2297 }
2298 } else {
2299 ret = 1;
2300 }
2301 }
2302 device_unlock(dev);
2303
2304 return ret;
2305}
2306
2307struct root_device {
2308 struct device dev;
2309 struct module *owner;
2310};
2311
2312static inline struct root_device *to_root_device(struct device *d)
2313{
2314 return container_of(d, struct root_device, dev);
2315}
2316
2317static void root_device_release(struct device *dev)
2318{
2319 kfree(to_root_device(dev));
2320}
2321
2322/**
2323 * __root_device_register - allocate and register a root device
2324 * @name: root device name
2325 * @owner: owner module of the root device, usually THIS_MODULE
2326 *
2327 * This function allocates a root device and registers it
2328 * using device_register(). In order to free the returned
2329 * device, use root_device_unregister().
2330 *
2331 * Root devices are dummy devices which allow other devices
2332 * to be grouped under /sys/devices. Use this function to
2333 * allocate a root device and then use it as the parent of
2334 * any device which should appear under /sys/devices/{name}
2335 *
2336 * The /sys/devices/{name} directory will also contain a
2337 * 'module' symlink which points to the @owner directory
2338 * in sysfs.
2339 *
2340 * Returns &struct device pointer on success, or ERR_PTR() on error.
2341 *
2342 * Note: You probably want to use root_device_register().
2343 */
2344struct device *__root_device_register(const char *name, struct module *owner)
2345{
2346 struct root_device *root;
2347 int err = -ENOMEM;
2348
2349 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
2350 if (!root)
2351 return ERR_PTR(err);
2352
2353 err = dev_set_name(&root->dev, "%s", name);
2354 if (err) {
2355 kfree(root);
2356 return ERR_PTR(err);
2357 }
2358
2359 root->dev.release = root_device_release;
2360
2361 err = device_register(&root->dev);
2362 if (err) {
2363 put_device(&root->dev);
2364 return ERR_PTR(err);
2365 }
2366
2367#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
2368 if (owner) {
2369 struct module_kobject *mk = &owner->mkobj;
2370
2371 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
2372 if (err) {
2373 device_unregister(&root->dev);
2374 return ERR_PTR(err);
2375 }
2376 root->owner = owner;
2377 }
2378#endif
2379
2380 return &root->dev;
2381}
2382EXPORT_SYMBOL_GPL(__root_device_register);
2383
2384/**
2385 * root_device_unregister - unregister and free a root device
2386 * @dev: device going away
2387 *
2388 * This function unregisters and cleans up a device that was created by
2389 * root_device_register().
2390 */
2391void root_device_unregister(struct device *dev)
2392{
2393 struct root_device *root = to_root_device(dev);
2394
2395 if (root->owner)
2396 sysfs_remove_link(&root->dev.kobj, "module");
2397
2398 device_unregister(dev);
2399}
2400EXPORT_SYMBOL_GPL(root_device_unregister);
2401
2402
2403static void device_create_release(struct device *dev)
2404{
2405 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
2406 kfree(dev);
2407}
2408
2409static struct device *
2410device_create_groups_vargs(struct class *class, struct device *parent,
2411 dev_t devt, void *drvdata,
2412 const struct attribute_group **groups,
2413 const char *fmt, va_list args)
2414{
2415 struct device *dev = NULL;
2416 int retval = -ENODEV;
2417
2418 if (class == NULL || IS_ERR(class))
2419 goto error;
2420
2421 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2422 if (!dev) {
2423 retval = -ENOMEM;
2424 goto error;
2425 }
2426
2427 device_initialize(dev);
2428 dev->devt = devt;
2429 dev->class = class;
2430 dev->parent = parent;
2431 dev->groups = groups;
2432 dev->release = device_create_release;
2433 dev_set_drvdata(dev, drvdata);
2434
2435 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
2436 if (retval)
2437 goto error;
2438
2439 retval = device_add(dev);
2440 if (retval)
2441 goto error;
2442
2443 return dev;
2444
2445error:
2446 put_device(dev);
2447 return ERR_PTR(retval);
2448}
2449
2450/**
2451 * device_create_vargs - creates a device and registers it with sysfs
2452 * @class: pointer to the struct class that this device should be registered to
2453 * @parent: pointer to the parent struct device of this new device, if any
2454 * @devt: the dev_t for the char device to be added
2455 * @drvdata: the data to be added to the device for callbacks
2456 * @fmt: string for the device's name
2457 * @args: va_list for the device's name
2458 *
2459 * This function can be used by char device classes. A struct device
2460 * will be created in sysfs, registered to the specified class.
2461 *
2462 * A "dev" file will be created, showing the dev_t for the device, if
2463 * the dev_t is not 0,0.
2464 * If a pointer to a parent struct device is passed in, the newly created
2465 * struct device will be a child of that device in sysfs.
2466 * The pointer to the struct device will be returned from the call.
2467 * Any further sysfs files that might be required can be created using this
2468 * pointer.
2469 *
2470 * Returns &struct device pointer on success, or ERR_PTR() on error.
2471 *
2472 * Note: the struct class passed to this function must have previously
2473 * been created with a call to class_create().
2474 */
2475struct device *device_create_vargs(struct class *class, struct device *parent,
2476 dev_t devt, void *drvdata, const char *fmt,
2477 va_list args)
2478{
2479 return device_create_groups_vargs(class, parent, devt, drvdata, NULL,
2480 fmt, args);
2481}
2482EXPORT_SYMBOL_GPL(device_create_vargs);
2483
2484/**
2485 * device_create - creates a device and registers it with sysfs
2486 * @class: pointer to the struct class that this device should be registered to
2487 * @parent: pointer to the parent struct device of this new device, if any
2488 * @devt: the dev_t for the char device to be added
2489 * @drvdata: the data to be added to the device for callbacks
2490 * @fmt: string for the device's name
2491 *
2492 * This function can be used by char device classes. A struct device
2493 * will be created in sysfs, registered to the specified class.
2494 *
2495 * A "dev" file will be created, showing the dev_t for the device, if
2496 * the dev_t is not 0,0.
2497 * If a pointer to a parent struct device is passed in, the newly created
2498 * struct device will be a child of that device in sysfs.
2499 * The pointer to the struct device will be returned from the call.
2500 * Any further sysfs files that might be required can be created using this
2501 * pointer.
2502 *
2503 * Returns &struct device pointer on success, or ERR_PTR() on error.
2504 *
2505 * Note: the struct class passed to this function must have previously
2506 * been created with a call to class_create().
2507 */
2508struct device *device_create(struct class *class, struct device *parent,
2509 dev_t devt, void *drvdata, const char *fmt, ...)
2510{
2511 va_list vargs;
2512 struct device *dev;
2513
2514 va_start(vargs, fmt);
2515 dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
2516 va_end(vargs);
2517 return dev;
2518}
2519EXPORT_SYMBOL_GPL(device_create);
2520
2521/**
2522 * device_create_with_groups - creates a device and registers it with sysfs
2523 * @class: pointer to the struct class that this device should be registered to
2524 * @parent: pointer to the parent struct device of this new device, if any
2525 * @devt: the dev_t for the char device to be added
2526 * @drvdata: the data to be added to the device for callbacks
2527 * @groups: NULL-terminated list of attribute groups to be created
2528 * @fmt: string for the device's name
2529 *
2530 * This function can be used by char device classes. A struct device
2531 * will be created in sysfs, registered to the specified class.
2532 * Additional attributes specified in the groups parameter will also
2533 * be created automatically.
2534 *
2535 * A "dev" file will be created, showing the dev_t for the device, if
2536 * the dev_t is not 0,0.
2537 * If a pointer to a parent struct device is passed in, the newly created
2538 * struct device will be a child of that device in sysfs.
2539 * The pointer to the struct device will be returned from the call.
2540 * Any further sysfs files that might be required can be created using this
2541 * pointer.
2542 *
2543 * Returns &struct device pointer on success, or ERR_PTR() on error.
2544 *
2545 * Note: the struct class passed to this function must have previously
2546 * been created with a call to class_create().
2547 */
2548struct device *device_create_with_groups(struct class *class,
2549 struct device *parent, dev_t devt,
2550 void *drvdata,
2551 const struct attribute_group **groups,
2552 const char *fmt, ...)
2553{
2554 va_list vargs;
2555 struct device *dev;
2556
2557 va_start(vargs, fmt);
2558 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
2559 fmt, vargs);
2560 va_end(vargs);
2561 return dev;
2562}
2563EXPORT_SYMBOL_GPL(device_create_with_groups);
2564
2565static int __match_devt(struct device *dev, const void *data)
2566{
2567 const dev_t *devt = data;
2568
2569 return dev->devt == *devt;
2570}
2571
2572/**
2573 * device_destroy - removes a device that was created with device_create()
2574 * @class: pointer to the struct class that this device was registered with
2575 * @devt: the dev_t of the device that was previously registered
2576 *
2577 * This call unregisters and cleans up a device that was created with a
2578 * call to device_create().
2579 */
2580void device_destroy(struct class *class, dev_t devt)
2581{
2582 struct device *dev;
2583
2584 dev = class_find_device(class, NULL, &devt, __match_devt);
2585 if (dev) {
2586 put_device(dev);
2587 device_unregister(dev);
2588 }
2589}
2590EXPORT_SYMBOL_GPL(device_destroy);
2591
2592/**
2593 * device_rename - renames a device
2594 * @dev: the pointer to the struct device to be renamed
2595 * @new_name: the new name of the device
2596 *
2597 * It is the responsibility of the caller to provide mutual
2598 * exclusion between two different calls of device_rename
2599 * on the same device to ensure that new_name is valid and
2600 * won't conflict with other devices.
2601 *
2602 * Note: Don't call this function. Currently, the networking layer calls this
2603 * function, but that will change. The following text from Kay Sievers offers
2604 * some insight:
2605 *
2606 * Renaming devices is racy at many levels, symlinks and other stuff are not
2607 * replaced atomically, and you get a "move" uevent, but it's not easy to
2608 * connect the event to the old and new device. Device nodes are not renamed at
2609 * all, there isn't even support for that in the kernel now.
2610 *
2611 * In the meantime, during renaming, your target name might be taken by another
2612 * driver, creating conflicts. Or the old name is taken directly after you
2613 * renamed it -- then you get events for the same DEVPATH, before you even see
2614 * the "move" event. It's just a mess, and nothing new should ever rely on
2615 * kernel device renaming. Besides that, it's not even implemented now for
2616 * other things than (driver-core wise very simple) network devices.
2617 *
2618 * We are currently about to change network renaming in udev to completely
2619 * disallow renaming of devices in the same namespace as the kernel uses,
2620 * because we can't solve the problems properly, that arise with swapping names
2621 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
2622 * be allowed to some other name than eth[0-9]*, for the aforementioned
2623 * reasons.
2624 *
2625 * Make up a "real" name in the driver before you register anything, or add
2626 * some other attributes for userspace to find the device, or use udev to add
2627 * symlinks -- but never rename kernel devices later, it's a complete mess. We
2628 * don't even want to get into that and try to implement the missing pieces in
2629 * the core. We really have other pieces to fix in the driver core mess. :)
2630 */
2631int device_rename(struct device *dev, const char *new_name)
2632{
2633 struct kobject *kobj = &dev->kobj;
2634 char *old_device_name = NULL;
2635 int error;
2636
2637 dev = get_device(dev);
2638 if (!dev)
2639 return -EINVAL;
2640
2641 dev_dbg(dev, "renaming to %s\n", new_name);
2642
2643 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
2644 if (!old_device_name) {
2645 error = -ENOMEM;
2646 goto out;
2647 }
2648
2649 if (dev->class) {
2650 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
2651 kobj, old_device_name,
2652 new_name, kobject_namespace(kobj));
2653 if (error)
2654 goto out;
2655 }
2656
2657 error = kobject_rename(kobj, new_name);
2658 if (error)
2659 goto out;
2660
2661out:
2662 put_device(dev);
2663
2664 kfree(old_device_name);
2665
2666 return error;
2667}
2668EXPORT_SYMBOL_GPL(device_rename);
2669
2670static int device_move_class_links(struct device *dev,
2671 struct device *old_parent,
2672 struct device *new_parent)
2673{
2674 int error = 0;
2675
2676 if (old_parent)
2677 sysfs_remove_link(&dev->kobj, "device");
2678 if (new_parent)
2679 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
2680 "device");
2681 return error;
2682}
2683
2684/**
2685 * device_move - moves a device to a new parent
2686 * @dev: the pointer to the struct device to be moved
2687 * @new_parent: the new parent of the device (can by NULL)
2688 * @dpm_order: how to reorder the dpm_list
2689 */
2690int device_move(struct device *dev, struct device *new_parent,
2691 enum dpm_order dpm_order)
2692{
2693 int error;
2694 struct device *old_parent;
2695 struct kobject *new_parent_kobj;
2696
2697 dev = get_device(dev);
2698 if (!dev)
2699 return -EINVAL;
2700
2701 device_pm_lock();
2702 new_parent = get_device(new_parent);
2703 new_parent_kobj = get_device_parent(dev, new_parent);
2704
2705 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
2706 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
2707 error = kobject_move(&dev->kobj, new_parent_kobj);
2708 if (error) {
2709 cleanup_glue_dir(dev, new_parent_kobj);
2710 put_device(new_parent);
2711 goto out;
2712 }
2713 old_parent = dev->parent;
2714 dev->parent = new_parent;
2715 if (old_parent)
2716 klist_remove(&dev->p->knode_parent);
2717 if (new_parent) {
2718 klist_add_tail(&dev->p->knode_parent,
2719 &new_parent->p->klist_children);
2720 set_dev_node(dev, dev_to_node(new_parent));
2721 }
2722
2723 if (dev->class) {
2724 error = device_move_class_links(dev, old_parent, new_parent);
2725 if (error) {
2726 /* We ignore errors on cleanup since we're hosed anyway... */
2727 device_move_class_links(dev, new_parent, old_parent);
2728 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
2729 if (new_parent)
2730 klist_remove(&dev->p->knode_parent);
2731 dev->parent = old_parent;
2732 if (old_parent) {
2733 klist_add_tail(&dev->p->knode_parent,
2734 &old_parent->p->klist_children);
2735 set_dev_node(dev, dev_to_node(old_parent));
2736 }
2737 }
2738 cleanup_glue_dir(dev, new_parent_kobj);
2739 put_device(new_parent);
2740 goto out;
2741 }
2742 }
2743 switch (dpm_order) {
2744 case DPM_ORDER_NONE:
2745 break;
2746 case DPM_ORDER_DEV_AFTER_PARENT:
2747 device_pm_move_after(dev, new_parent);
2748 devices_kset_move_after(dev, new_parent);
2749 break;
2750 case DPM_ORDER_PARENT_BEFORE_DEV:
2751 device_pm_move_before(new_parent, dev);
2752 devices_kset_move_before(new_parent, dev);
2753 break;
2754 case DPM_ORDER_DEV_LAST:
2755 device_pm_move_last(dev);
2756 devices_kset_move_last(dev);
2757 break;
2758 }
2759
2760 put_device(old_parent);
2761out:
2762 device_pm_unlock();
2763 put_device(dev);
2764 return error;
2765}
2766EXPORT_SYMBOL_GPL(device_move);
2767
2768/**
2769 * device_shutdown - call ->shutdown() on each device to shutdown.
2770 */
2771void device_shutdown(void)
2772{
2773 struct device *dev, *parent;
2774
2775 spin_lock(&devices_kset->list_lock);
2776 /*
2777 * Walk the devices list backward, shutting down each in turn.
2778 * Beware that device unplug events may also start pulling
2779 * devices offline, even as the system is shutting down.
2780 */
2781 while (!list_empty(&devices_kset->list)) {
2782 dev = list_entry(devices_kset->list.prev, struct device,
2783 kobj.entry);
2784
2785 /*
2786 * hold reference count of device's parent to
2787 * prevent it from being freed because parent's
2788 * lock is to be held
2789 */
2790 parent = get_device(dev->parent);
2791 get_device(dev);
2792 /*
2793 * Make sure the device is off the kset list, in the
2794 * event that dev->*->shutdown() doesn't remove it.
2795 */
2796 list_del_init(&dev->kobj.entry);
2797 spin_unlock(&devices_kset->list_lock);
2798
2799 /* hold lock to avoid race with probe/release */
2800 if (parent)
2801 device_lock(parent);
2802 device_lock(dev);
2803
2804 /* Don't allow any more runtime suspends */
2805 pm_runtime_get_noresume(dev);
2806 pm_runtime_barrier(dev);
2807
2808 if (dev->class && dev->class->shutdown_pre) {
2809 if (initcall_debug)
2810 dev_info(dev, "shutdown_pre\n");
2811 dev->class->shutdown_pre(dev);
2812 }
2813 if (dev->bus && dev->bus->shutdown) {
2814 if (initcall_debug)
2815 dev_info(dev, "shutdown\n");
2816 dev->bus->shutdown(dev);
2817 } else if (dev->driver && dev->driver->shutdown) {
2818 if (initcall_debug)
2819 dev_info(dev, "shutdown\n");
2820 dev->driver->shutdown(dev);
2821 }
2822
2823 device_unlock(dev);
2824 if (parent)
2825 device_unlock(parent);
2826
2827 put_device(dev);
2828 put_device(parent);
2829
2830 spin_lock(&devices_kset->list_lock);
2831 }
2832 spin_unlock(&devices_kset->list_lock);
2833}
2834
2835/*
2836 * Device logging functions
2837 */
2838
2839#ifdef CONFIG_PRINTK
2840static int
2841create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
2842{
2843 const char *subsys;
2844 size_t pos = 0;
2845
2846 if (dev->class)
2847 subsys = dev->class->name;
2848 else if (dev->bus)
2849 subsys = dev->bus->name;
2850 else
2851 return 0;
2852
2853 pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
2854 if (pos >= hdrlen)
2855 goto overflow;
2856
2857 /*
2858 * Add device identifier DEVICE=:
2859 * b12:8 block dev_t
2860 * c127:3 char dev_t
2861 * n8 netdev ifindex
2862 * +sound:card0 subsystem:devname
2863 */
2864 if (MAJOR(dev->devt)) {
2865 char c;
2866
2867 if (strcmp(subsys, "block") == 0)
2868 c = 'b';
2869 else
2870 c = 'c';
2871 pos++;
2872 pos += snprintf(hdr + pos, hdrlen - pos,
2873 "DEVICE=%c%u:%u",
2874 c, MAJOR(dev->devt), MINOR(dev->devt));
2875 } else if (strcmp(subsys, "net") == 0) {
2876 struct net_device *net = to_net_dev(dev);
2877
2878 pos++;
2879 pos += snprintf(hdr + pos, hdrlen - pos,
2880 "DEVICE=n%u", net->ifindex);
2881 } else {
2882 pos++;
2883 pos += snprintf(hdr + pos, hdrlen - pos,
2884 "DEVICE=+%s:%s", subsys, dev_name(dev));
2885 }
2886
2887 if (pos >= hdrlen)
2888 goto overflow;
2889
2890 return pos;
2891
2892overflow:
2893 dev_WARN(dev, "device/subsystem name too long");
2894 return 0;
2895}
2896
2897int dev_vprintk_emit(int level, const struct device *dev,
2898 const char *fmt, va_list args)
2899{
2900 char hdr[128];
2901 size_t hdrlen;
2902
2903 hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
2904
2905 return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
2906}
2907EXPORT_SYMBOL(dev_vprintk_emit);
2908
2909int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
2910{
2911 va_list args;
2912 int r;
2913
2914 va_start(args, fmt);
2915
2916 r = dev_vprintk_emit(level, dev, fmt, args);
2917
2918 va_end(args);
2919
2920 return r;
2921}
2922EXPORT_SYMBOL(dev_printk_emit);
2923
2924static void __dev_printk(const char *level, const struct device *dev,
2925 struct va_format *vaf)
2926{
2927 if (dev)
2928 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
2929 dev_driver_string(dev), dev_name(dev), vaf);
2930 else
2931 printk("%s(NULL device *): %pV", level, vaf);
2932}
2933
2934void dev_printk(const char *level, const struct device *dev,
2935 const char *fmt, ...)
2936{
2937 struct va_format vaf;
2938 va_list args;
2939
2940 va_start(args, fmt);
2941
2942 vaf.fmt = fmt;
2943 vaf.va = &args;
2944
2945 __dev_printk(level, dev, &vaf);
2946
2947 va_end(args);
2948}
2949EXPORT_SYMBOL(dev_printk);
2950
2951#define define_dev_printk_level(func, kern_level) \
2952void func(const struct device *dev, const char *fmt, ...) \
2953{ \
2954 struct va_format vaf; \
2955 va_list args; \
2956 \
2957 va_start(args, fmt); \
2958 \
2959 vaf.fmt = fmt; \
2960 vaf.va = &args; \
2961 \
2962 __dev_printk(kern_level, dev, &vaf); \
2963 \
2964 va_end(args); \
2965} \
2966EXPORT_SYMBOL(func);
2967
2968define_dev_printk_level(dev_emerg, KERN_EMERG);
2969define_dev_printk_level(dev_alert, KERN_ALERT);
2970define_dev_printk_level(dev_crit, KERN_CRIT);
2971define_dev_printk_level(dev_err, KERN_ERR);
2972define_dev_printk_level(dev_warn, KERN_WARNING);
2973define_dev_printk_level(dev_notice, KERN_NOTICE);
2974define_dev_printk_level(_dev_info, KERN_INFO);
2975
2976#endif
2977
2978static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
2979{
2980 return fwnode && !IS_ERR(fwnode->secondary);
2981}
2982
2983/**
2984 * set_primary_fwnode - Change the primary firmware node of a given device.
2985 * @dev: Device to handle.
2986 * @fwnode: New primary firmware node of the device.
2987 *
2988 * Set the device's firmware node pointer to @fwnode, but if a secondary
2989 * firmware node of the device is present, preserve it.
2990 */
2991void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
2992{
2993 if (fwnode) {
2994 struct fwnode_handle *fn = dev->fwnode;
2995
2996 if (fwnode_is_primary(fn))
2997 fn = fn->secondary;
2998
2999 if (fn) {
3000 WARN_ON(fwnode->secondary);
3001 fwnode->secondary = fn;
3002 }
3003 dev->fwnode = fwnode;
3004 } else {
3005 dev->fwnode = fwnode_is_primary(dev->fwnode) ?
3006 dev->fwnode->secondary : NULL;
3007 }
3008}
3009EXPORT_SYMBOL_GPL(set_primary_fwnode);
3010
3011/**
3012 * set_secondary_fwnode - Change the secondary firmware node of a given device.
3013 * @dev: Device to handle.
3014 * @fwnode: New secondary firmware node of the device.
3015 *
3016 * If a primary firmware node of the device is present, set its secondary
3017 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
3018 * @fwnode.
3019 */
3020void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
3021{
3022 if (fwnode)
3023 fwnode->secondary = ERR_PTR(-ENODEV);
3024
3025 if (fwnode_is_primary(dev->fwnode))
3026 dev->fwnode->secondary = fwnode;
3027 else
3028 dev->fwnode = fwnode;
3029}
3030
3031/**
3032 * device_set_of_node_from_dev - reuse device-tree node of another device
3033 * @dev: device whose device-tree node is being set
3034 * @dev2: device whose device-tree node is being reused
3035 *
3036 * Takes another reference to the new device-tree node after first dropping
3037 * any reference held to the old node.
3038 */
3039void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
3040{
3041 of_node_put(dev->of_node);
3042 dev->of_node = of_node_get(dev2->of_node);
3043 dev->of_node_reused = true;
3044}
3045EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);