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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/module.h>
18#include <linux/slab.h>
19#include <linux/string.h>
20#include <linux/kdev_t.h>
21#include <linux/notifier.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/genhd.h>
25#include <linux/mutex.h>
26#include <linux/pm_runtime.h>
27#include <linux/netdevice.h>
28#include <linux/sched/signal.h>
29#include <linux/sysfs.h>
30
31#include "base.h"
32#include "power/power.h"
33
34#ifdef CONFIG_SYSFS_DEPRECATED
35#ifdef CONFIG_SYSFS_DEPRECATED_V2
36long sysfs_deprecated = 1;
37#else
38long sysfs_deprecated = 0;
39#endif
40static int __init sysfs_deprecated_setup(char *arg)
41{
42 return kstrtol(arg, 10, &sysfs_deprecated);
43}
44early_param("sysfs.deprecated", sysfs_deprecated_setup);
45#endif
46
47/* Device links support. */
48static LIST_HEAD(wait_for_suppliers);
49static DEFINE_MUTEX(wfs_lock);
50static LIST_HEAD(deferred_sync);
51static unsigned int defer_sync_state_count = 1;
52static unsigned int defer_fw_devlink_count;
53static LIST_HEAD(deferred_fw_devlink);
54static DEFINE_MUTEX(defer_fw_devlink_lock);
55static bool fw_devlink_is_permissive(void);
56
57#ifdef CONFIG_SRCU
58static DEFINE_MUTEX(device_links_lock);
59DEFINE_STATIC_SRCU(device_links_srcu);
60
61static inline void device_links_write_lock(void)
62{
63 mutex_lock(&device_links_lock);
64}
65
66static inline void device_links_write_unlock(void)
67{
68 mutex_unlock(&device_links_lock);
69}
70
71int device_links_read_lock(void) __acquires(&device_links_srcu)
72{
73 return srcu_read_lock(&device_links_srcu);
74}
75
76void device_links_read_unlock(int idx) __releases(&device_links_srcu)
77{
78 srcu_read_unlock(&device_links_srcu, idx);
79}
80
81int device_links_read_lock_held(void)
82{
83 return srcu_read_lock_held(&device_links_srcu);
84}
85#else /* !CONFIG_SRCU */
86static DECLARE_RWSEM(device_links_lock);
87
88static inline void device_links_write_lock(void)
89{
90 down_write(&device_links_lock);
91}
92
93static inline void device_links_write_unlock(void)
94{
95 up_write(&device_links_lock);
96}
97
98int device_links_read_lock(void)
99{
100 down_read(&device_links_lock);
101 return 0;
102}
103
104void device_links_read_unlock(int not_used)
105{
106 up_read(&device_links_lock);
107}
108
109#ifdef CONFIG_DEBUG_LOCK_ALLOC
110int device_links_read_lock_held(void)
111{
112 return lockdep_is_held(&device_links_lock);
113}
114#endif
115#endif /* !CONFIG_SRCU */
116
117/**
118 * device_is_dependent - Check if one device depends on another one
119 * @dev: Device to check dependencies for.
120 * @target: Device to check against.
121 *
122 * Check if @target depends on @dev or any device dependent on it (its child or
123 * its consumer etc). Return 1 if that is the case or 0 otherwise.
124 */
125int device_is_dependent(struct device *dev, void *target)
126{
127 struct device_link *link;
128 int ret;
129
130 if (dev == target)
131 return 1;
132
133 ret = device_for_each_child(dev, target, device_is_dependent);
134 if (ret)
135 return ret;
136
137 list_for_each_entry(link, &dev->links.consumers, s_node) {
138 if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
139 continue;
140
141 if (link->consumer == target)
142 return 1;
143
144 ret = device_is_dependent(link->consumer, target);
145 if (ret)
146 break;
147 }
148 return ret;
149}
150
151static void device_link_init_status(struct device_link *link,
152 struct device *consumer,
153 struct device *supplier)
154{
155 switch (supplier->links.status) {
156 case DL_DEV_PROBING:
157 switch (consumer->links.status) {
158 case DL_DEV_PROBING:
159 /*
160 * A consumer driver can create a link to a supplier
161 * that has not completed its probing yet as long as it
162 * knows that the supplier is already functional (for
163 * example, it has just acquired some resources from the
164 * supplier).
165 */
166 link->status = DL_STATE_CONSUMER_PROBE;
167 break;
168 default:
169 link->status = DL_STATE_DORMANT;
170 break;
171 }
172 break;
173 case DL_DEV_DRIVER_BOUND:
174 switch (consumer->links.status) {
175 case DL_DEV_PROBING:
176 link->status = DL_STATE_CONSUMER_PROBE;
177 break;
178 case DL_DEV_DRIVER_BOUND:
179 link->status = DL_STATE_ACTIVE;
180 break;
181 default:
182 link->status = DL_STATE_AVAILABLE;
183 break;
184 }
185 break;
186 case DL_DEV_UNBINDING:
187 link->status = DL_STATE_SUPPLIER_UNBIND;
188 break;
189 default:
190 link->status = DL_STATE_DORMANT;
191 break;
192 }
193}
194
195static int device_reorder_to_tail(struct device *dev, void *not_used)
196{
197 struct device_link *link;
198
199 /*
200 * Devices that have not been registered yet will be put to the ends
201 * of the lists during the registration, so skip them here.
202 */
203 if (device_is_registered(dev))
204 devices_kset_move_last(dev);
205
206 if (device_pm_initialized(dev))
207 device_pm_move_last(dev);
208
209 device_for_each_child(dev, NULL, device_reorder_to_tail);
210 list_for_each_entry(link, &dev->links.consumers, s_node) {
211 if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
212 continue;
213 device_reorder_to_tail(link->consumer, NULL);
214 }
215
216 return 0;
217}
218
219/**
220 * device_pm_move_to_tail - Move set of devices to the end of device lists
221 * @dev: Device to move
222 *
223 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
224 *
225 * It moves the @dev along with all of its children and all of its consumers
226 * to the ends of the device_kset and dpm_list, recursively.
227 */
228void device_pm_move_to_tail(struct device *dev)
229{
230 int idx;
231
232 idx = device_links_read_lock();
233 device_pm_lock();
234 device_reorder_to_tail(dev, NULL);
235 device_pm_unlock();
236 device_links_read_unlock(idx);
237}
238
239#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
240
241static ssize_t status_show(struct device *dev,
242 struct device_attribute *attr, char *buf)
243{
244 char *status;
245
246 switch (to_devlink(dev)->status) {
247 case DL_STATE_NONE:
248 status = "not tracked"; break;
249 case DL_STATE_DORMANT:
250 status = "dormant"; break;
251 case DL_STATE_AVAILABLE:
252 status = "available"; break;
253 case DL_STATE_CONSUMER_PROBE:
254 status = "consumer probing"; break;
255 case DL_STATE_ACTIVE:
256 status = "active"; break;
257 case DL_STATE_SUPPLIER_UNBIND:
258 status = "supplier unbinding"; break;
259 default:
260 status = "unknown"; break;
261 }
262 return sprintf(buf, "%s\n", status);
263}
264static DEVICE_ATTR_RO(status);
265
266static ssize_t auto_remove_on_show(struct device *dev,
267 struct device_attribute *attr, char *buf)
268{
269 struct device_link *link = to_devlink(dev);
270 char *str;
271
272 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
273 str = "supplier unbind";
274 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
275 str = "consumer unbind";
276 else
277 str = "never";
278
279 return sprintf(buf, "%s\n", str);
280}
281static DEVICE_ATTR_RO(auto_remove_on);
282
283static ssize_t runtime_pm_show(struct device *dev,
284 struct device_attribute *attr, char *buf)
285{
286 struct device_link *link = to_devlink(dev);
287
288 return sprintf(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
289}
290static DEVICE_ATTR_RO(runtime_pm);
291
292static ssize_t sync_state_only_show(struct device *dev,
293 struct device_attribute *attr, char *buf)
294{
295 struct device_link *link = to_devlink(dev);
296
297 return sprintf(buf, "%d\n", !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
298}
299static DEVICE_ATTR_RO(sync_state_only);
300
301static struct attribute *devlink_attrs[] = {
302 &dev_attr_status.attr,
303 &dev_attr_auto_remove_on.attr,
304 &dev_attr_runtime_pm.attr,
305 &dev_attr_sync_state_only.attr,
306 NULL,
307};
308ATTRIBUTE_GROUPS(devlink);
309
310static void device_link_free(struct device_link *link)
311{
312 while (refcount_dec_not_one(&link->rpm_active))
313 pm_runtime_put(link->supplier);
314
315 put_device(link->consumer);
316 put_device(link->supplier);
317 kfree(link);
318}
319
320#ifdef CONFIG_SRCU
321static void __device_link_free_srcu(struct rcu_head *rhead)
322{
323 device_link_free(container_of(rhead, struct device_link, rcu_head));
324}
325
326static void devlink_dev_release(struct device *dev)
327{
328 struct device_link *link = to_devlink(dev);
329
330 call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
331}
332#else
333static void devlink_dev_release(struct device *dev)
334{
335 device_link_free(to_devlink(dev));
336}
337#endif
338
339static struct class devlink_class = {
340 .name = "devlink",
341 .owner = THIS_MODULE,
342 .dev_groups = devlink_groups,
343 .dev_release = devlink_dev_release,
344};
345
346static int devlink_add_symlinks(struct device *dev,
347 struct class_interface *class_intf)
348{
349 int ret;
350 size_t len;
351 struct device_link *link = to_devlink(dev);
352 struct device *sup = link->supplier;
353 struct device *con = link->consumer;
354 char *buf;
355
356 len = max(strlen(dev_name(sup)), strlen(dev_name(con)));
357 len += strlen("supplier:") + 1;
358 buf = kzalloc(len, GFP_KERNEL);
359 if (!buf)
360 return -ENOMEM;
361
362 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
363 if (ret)
364 goto out;
365
366 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
367 if (ret)
368 goto err_con;
369
370 snprintf(buf, len, "consumer:%s", dev_name(con));
371 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
372 if (ret)
373 goto err_con_dev;
374
375 snprintf(buf, len, "supplier:%s", dev_name(sup));
376 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
377 if (ret)
378 goto err_sup_dev;
379
380 goto out;
381
382err_sup_dev:
383 snprintf(buf, len, "consumer:%s", dev_name(con));
384 sysfs_remove_link(&sup->kobj, buf);
385err_con_dev:
386 sysfs_remove_link(&link->link_dev.kobj, "consumer");
387err_con:
388 sysfs_remove_link(&link->link_dev.kobj, "supplier");
389out:
390 kfree(buf);
391 return ret;
392}
393
394static void devlink_remove_symlinks(struct device *dev,
395 struct class_interface *class_intf)
396{
397 struct device_link *link = to_devlink(dev);
398 size_t len;
399 struct device *sup = link->supplier;
400 struct device *con = link->consumer;
401 char *buf;
402
403 sysfs_remove_link(&link->link_dev.kobj, "consumer");
404 sysfs_remove_link(&link->link_dev.kobj, "supplier");
405
406 len = max(strlen(dev_name(sup)), strlen(dev_name(con)));
407 len += strlen("supplier:") + 1;
408 buf = kzalloc(len, GFP_KERNEL);
409 if (!buf) {
410 WARN(1, "Unable to properly free device link symlinks!\n");
411 return;
412 }
413
414 snprintf(buf, len, "supplier:%s", dev_name(sup));
415 sysfs_remove_link(&con->kobj, buf);
416 snprintf(buf, len, "consumer:%s", dev_name(con));
417 sysfs_remove_link(&sup->kobj, buf);
418 kfree(buf);
419}
420
421static struct class_interface devlink_class_intf = {
422 .class = &devlink_class,
423 .add_dev = devlink_add_symlinks,
424 .remove_dev = devlink_remove_symlinks,
425};
426
427static int __init devlink_class_init(void)
428{
429 int ret;
430
431 ret = class_register(&devlink_class);
432 if (ret)
433 return ret;
434
435 ret = class_interface_register(&devlink_class_intf);
436 if (ret)
437 class_unregister(&devlink_class);
438
439 return ret;
440}
441postcore_initcall(devlink_class_init);
442
443#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
444 DL_FLAG_AUTOREMOVE_SUPPLIER | \
445 DL_FLAG_AUTOPROBE_CONSUMER | \
446 DL_FLAG_SYNC_STATE_ONLY)
447
448#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
449 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
450
451/**
452 * device_link_add - Create a link between two devices.
453 * @consumer: Consumer end of the link.
454 * @supplier: Supplier end of the link.
455 * @flags: Link flags.
456 *
457 * The caller is responsible for the proper synchronization of the link creation
458 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
459 * runtime PM framework to take the link into account. Second, if the
460 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
461 * be forced into the active metastate and reference-counted upon the creation
462 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
463 * ignored.
464 *
465 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
466 * expected to release the link returned by it directly with the help of either
467 * device_link_del() or device_link_remove().
468 *
469 * If that flag is not set, however, the caller of this function is handing the
470 * management of the link over to the driver core entirely and its return value
471 * can only be used to check whether or not the link is present. In that case,
472 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
473 * flags can be used to indicate to the driver core when the link can be safely
474 * deleted. Namely, setting one of them in @flags indicates to the driver core
475 * that the link is not going to be used (by the given caller of this function)
476 * after unbinding the consumer or supplier driver, respectively, from its
477 * device, so the link can be deleted at that point. If none of them is set,
478 * the link will be maintained until one of the devices pointed to by it (either
479 * the consumer or the supplier) is unregistered.
480 *
481 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
482 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
483 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
484 * be used to request the driver core to automaticall probe for a consmer
485 * driver after successfully binding a driver to the supplier device.
486 *
487 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
488 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
489 * the same time is invalid and will cause NULL to be returned upfront.
490 * However, if a device link between the given @consumer and @supplier pair
491 * exists already when this function is called for them, the existing link will
492 * be returned regardless of its current type and status (the link's flags may
493 * be modified then). The caller of this function is then expected to treat
494 * the link as though it has just been created, so (in particular) if
495 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
496 * explicitly when not needed any more (as stated above).
497 *
498 * A side effect of the link creation is re-ordering of dpm_list and the
499 * devices_kset list by moving the consumer device and all devices depending
500 * on it to the ends of these lists (that does not happen to devices that have
501 * not been registered when this function is called).
502 *
503 * The supplier device is required to be registered when this function is called
504 * and NULL will be returned if that is not the case. The consumer device need
505 * not be registered, however.
506 */
507struct device_link *device_link_add(struct device *consumer,
508 struct device *supplier, u32 flags)
509{
510 struct device_link *link;
511
512 if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS ||
513 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
514 (flags & DL_FLAG_SYNC_STATE_ONLY &&
515 flags != DL_FLAG_SYNC_STATE_ONLY) ||
516 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
517 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
518 DL_FLAG_AUTOREMOVE_SUPPLIER)))
519 return NULL;
520
521 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
522 if (pm_runtime_get_sync(supplier) < 0) {
523 pm_runtime_put_noidle(supplier);
524 return NULL;
525 }
526 }
527
528 if (!(flags & DL_FLAG_STATELESS))
529 flags |= DL_FLAG_MANAGED;
530
531 device_links_write_lock();
532 device_pm_lock();
533
534 /*
535 * If the supplier has not been fully registered yet or there is a
536 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
537 * the supplier already in the graph, return NULL. If the link is a
538 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
539 * because it only affects sync_state() callbacks.
540 */
541 if (!device_pm_initialized(supplier)
542 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
543 device_is_dependent(consumer, supplier))) {
544 link = NULL;
545 goto out;
546 }
547
548 /*
549 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
550 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
551 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
552 */
553 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
554 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
555
556 list_for_each_entry(link, &supplier->links.consumers, s_node) {
557 if (link->consumer != consumer)
558 continue;
559
560 if (flags & DL_FLAG_PM_RUNTIME) {
561 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
562 pm_runtime_new_link(consumer);
563 link->flags |= DL_FLAG_PM_RUNTIME;
564 }
565 if (flags & DL_FLAG_RPM_ACTIVE)
566 refcount_inc(&link->rpm_active);
567 }
568
569 if (flags & DL_FLAG_STATELESS) {
570 kref_get(&link->kref);
571 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
572 !(link->flags & DL_FLAG_STATELESS)) {
573 link->flags |= DL_FLAG_STATELESS;
574 goto reorder;
575 } else {
576 link->flags |= DL_FLAG_STATELESS;
577 goto out;
578 }
579 }
580
581 /*
582 * If the life time of the link following from the new flags is
583 * longer than indicated by the flags of the existing link,
584 * update the existing link to stay around longer.
585 */
586 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
587 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
588 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
589 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
590 }
591 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
592 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
593 DL_FLAG_AUTOREMOVE_SUPPLIER);
594 }
595 if (!(link->flags & DL_FLAG_MANAGED)) {
596 kref_get(&link->kref);
597 link->flags |= DL_FLAG_MANAGED;
598 device_link_init_status(link, consumer, supplier);
599 }
600 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
601 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
602 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
603 goto reorder;
604 }
605
606 goto out;
607 }
608
609 link = kzalloc(sizeof(*link), GFP_KERNEL);
610 if (!link)
611 goto out;
612
613 refcount_set(&link->rpm_active, 1);
614
615 get_device(supplier);
616 link->supplier = supplier;
617 INIT_LIST_HEAD(&link->s_node);
618 get_device(consumer);
619 link->consumer = consumer;
620 INIT_LIST_HEAD(&link->c_node);
621 link->flags = flags;
622 kref_init(&link->kref);
623
624 link->link_dev.class = &devlink_class;
625 device_set_pm_not_required(&link->link_dev);
626 dev_set_name(&link->link_dev, "%s--%s",
627 dev_name(supplier), dev_name(consumer));
628 if (device_register(&link->link_dev)) {
629 put_device(consumer);
630 put_device(supplier);
631 kfree(link);
632 link = NULL;
633 goto out;
634 }
635
636 if (flags & DL_FLAG_PM_RUNTIME) {
637 if (flags & DL_FLAG_RPM_ACTIVE)
638 refcount_inc(&link->rpm_active);
639
640 pm_runtime_new_link(consumer);
641 }
642
643 /* Determine the initial link state. */
644 if (flags & DL_FLAG_STATELESS)
645 link->status = DL_STATE_NONE;
646 else
647 device_link_init_status(link, consumer, supplier);
648
649 /*
650 * Some callers expect the link creation during consumer driver probe to
651 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
652 */
653 if (link->status == DL_STATE_CONSUMER_PROBE &&
654 flags & DL_FLAG_PM_RUNTIME)
655 pm_runtime_resume(supplier);
656
657 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
658 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
659
660 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
661 dev_dbg(consumer,
662 "Linked as a sync state only consumer to %s\n",
663 dev_name(supplier));
664 goto out;
665 }
666
667reorder:
668 /*
669 * Move the consumer and all of the devices depending on it to the end
670 * of dpm_list and the devices_kset list.
671 *
672 * It is necessary to hold dpm_list locked throughout all that or else
673 * we may end up suspending with a wrong ordering of it.
674 */
675 device_reorder_to_tail(consumer, NULL);
676
677 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
678
679out:
680 device_pm_unlock();
681 device_links_write_unlock();
682
683 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
684 pm_runtime_put(supplier);
685
686 return link;
687}
688EXPORT_SYMBOL_GPL(device_link_add);
689
690/**
691 * device_link_wait_for_supplier - Add device to wait_for_suppliers list
692 * @consumer: Consumer device
693 *
694 * Marks the @consumer device as waiting for suppliers to become available by
695 * adding it to the wait_for_suppliers list. The consumer device will never be
696 * probed until it's removed from the wait_for_suppliers list.
697 *
698 * The caller is responsible for adding the links to the supplier devices once
699 * they are available and removing the @consumer device from the
700 * wait_for_suppliers list once links to all the suppliers have been created.
701 *
702 * This function is NOT meant to be called from the probe function of the
703 * consumer but rather from code that creates/adds the consumer device.
704 */
705static void device_link_wait_for_supplier(struct device *consumer,
706 bool need_for_probe)
707{
708 mutex_lock(&wfs_lock);
709 list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers);
710 consumer->links.need_for_probe = need_for_probe;
711 mutex_unlock(&wfs_lock);
712}
713
714static void device_link_wait_for_mandatory_supplier(struct device *consumer)
715{
716 device_link_wait_for_supplier(consumer, true);
717}
718
719static void device_link_wait_for_optional_supplier(struct device *consumer)
720{
721 device_link_wait_for_supplier(consumer, false);
722}
723
724/**
725 * device_link_add_missing_supplier_links - Add links from consumer devices to
726 * supplier devices, leaving any
727 * consumer with inactive suppliers on
728 * the wait_for_suppliers list
729 *
730 * Loops through all consumers waiting on suppliers and tries to add all their
731 * supplier links. If that succeeds, the consumer device is removed from
732 * wait_for_suppliers list. Otherwise, they are left in the wait_for_suppliers
733 * list. Devices left on the wait_for_suppliers list will not be probed.
734 *
735 * The fwnode add_links callback is expected to return 0 if it has found and
736 * added all the supplier links for the consumer device. It should return an
737 * error if it isn't able to do so.
738 *
739 * The caller of device_link_wait_for_supplier() is expected to call this once
740 * it's aware of potential suppliers becoming available.
741 */
742static void device_link_add_missing_supplier_links(void)
743{
744 struct device *dev, *tmp;
745
746 mutex_lock(&wfs_lock);
747 list_for_each_entry_safe(dev, tmp, &wait_for_suppliers,
748 links.needs_suppliers) {
749 int ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
750 if (!ret)
751 list_del_init(&dev->links.needs_suppliers);
752 else if (ret != -ENODEV || fw_devlink_is_permissive())
753 dev->links.need_for_probe = false;
754 }
755 mutex_unlock(&wfs_lock);
756}
757
758#ifdef CONFIG_SRCU
759static void __device_link_del(struct kref *kref)
760{
761 struct device_link *link = container_of(kref, struct device_link, kref);
762
763 dev_dbg(link->consumer, "Dropping the link to %s\n",
764 dev_name(link->supplier));
765
766 if (link->flags & DL_FLAG_PM_RUNTIME)
767 pm_runtime_drop_link(link->consumer);
768
769 list_del_rcu(&link->s_node);
770 list_del_rcu(&link->c_node);
771 device_unregister(&link->link_dev);
772}
773#else /* !CONFIG_SRCU */
774static void __device_link_del(struct kref *kref)
775{
776 struct device_link *link = container_of(kref, struct device_link, kref);
777
778 dev_info(link->consumer, "Dropping the link to %s\n",
779 dev_name(link->supplier));
780
781 if (link->flags & DL_FLAG_PM_RUNTIME)
782 pm_runtime_drop_link(link->consumer);
783
784 list_del(&link->s_node);
785 list_del(&link->c_node);
786 device_unregister(&link->link_dev);
787}
788#endif /* !CONFIG_SRCU */
789
790static void device_link_put_kref(struct device_link *link)
791{
792 if (link->flags & DL_FLAG_STATELESS)
793 kref_put(&link->kref, __device_link_del);
794 else
795 WARN(1, "Unable to drop a managed device link reference\n");
796}
797
798/**
799 * device_link_del - Delete a stateless link between two devices.
800 * @link: Device link to delete.
801 *
802 * The caller must ensure proper synchronization of this function with runtime
803 * PM. If the link was added multiple times, it needs to be deleted as often.
804 * Care is required for hotplugged devices: Their links are purged on removal
805 * and calling device_link_del() is then no longer allowed.
806 */
807void device_link_del(struct device_link *link)
808{
809 device_links_write_lock();
810 device_link_put_kref(link);
811 device_links_write_unlock();
812}
813EXPORT_SYMBOL_GPL(device_link_del);
814
815/**
816 * device_link_remove - Delete a stateless link between two devices.
817 * @consumer: Consumer end of the link.
818 * @supplier: Supplier end of the link.
819 *
820 * The caller must ensure proper synchronization of this function with runtime
821 * PM.
822 */
823void device_link_remove(void *consumer, struct device *supplier)
824{
825 struct device_link *link;
826
827 if (WARN_ON(consumer == supplier))
828 return;
829
830 device_links_write_lock();
831
832 list_for_each_entry(link, &supplier->links.consumers, s_node) {
833 if (link->consumer == consumer) {
834 device_link_put_kref(link);
835 break;
836 }
837 }
838
839 device_links_write_unlock();
840}
841EXPORT_SYMBOL_GPL(device_link_remove);
842
843static void device_links_missing_supplier(struct device *dev)
844{
845 struct device_link *link;
846
847 list_for_each_entry(link, &dev->links.suppliers, c_node) {
848 if (link->status != DL_STATE_CONSUMER_PROBE)
849 continue;
850
851 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
852 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
853 } else {
854 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
855 WRITE_ONCE(link->status, DL_STATE_DORMANT);
856 }
857 }
858}
859
860/**
861 * device_links_check_suppliers - Check presence of supplier drivers.
862 * @dev: Consumer device.
863 *
864 * Check links from this device to any suppliers. Walk the list of the device's
865 * links to suppliers and see if all of them are available. If not, simply
866 * return -EPROBE_DEFER.
867 *
868 * We need to guarantee that the supplier will not go away after the check has
869 * been positive here. It only can go away in __device_release_driver() and
870 * that function checks the device's links to consumers. This means we need to
871 * mark the link as "consumer probe in progress" to make the supplier removal
872 * wait for us to complete (or bad things may happen).
873 *
874 * Links without the DL_FLAG_MANAGED flag set are ignored.
875 */
876int device_links_check_suppliers(struct device *dev)
877{
878 struct device_link *link;
879 int ret = 0;
880
881 /*
882 * Device waiting for supplier to become available is not allowed to
883 * probe.
884 */
885 mutex_lock(&wfs_lock);
886 if (!list_empty(&dev->links.needs_suppliers) &&
887 dev->links.need_for_probe) {
888 mutex_unlock(&wfs_lock);
889 return -EPROBE_DEFER;
890 }
891 mutex_unlock(&wfs_lock);
892
893 device_links_write_lock();
894
895 list_for_each_entry(link, &dev->links.suppliers, c_node) {
896 if (!(link->flags & DL_FLAG_MANAGED))
897 continue;
898
899 if (link->status != DL_STATE_AVAILABLE &&
900 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
901 device_links_missing_supplier(dev);
902 ret = -EPROBE_DEFER;
903 break;
904 }
905 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
906 }
907 dev->links.status = DL_DEV_PROBING;
908
909 device_links_write_unlock();
910 return ret;
911}
912
913/**
914 * __device_links_queue_sync_state - Queue a device for sync_state() callback
915 * @dev: Device to call sync_state() on
916 * @list: List head to queue the @dev on
917 *
918 * Queues a device for a sync_state() callback when the device links write lock
919 * isn't held. This allows the sync_state() execution flow to use device links
920 * APIs. The caller must ensure this function is called with
921 * device_links_write_lock() held.
922 *
923 * This function does a get_device() to make sure the device is not freed while
924 * on this list.
925 *
926 * So the caller must also ensure that device_links_flush_sync_list() is called
927 * as soon as the caller releases device_links_write_lock(). This is necessary
928 * to make sure the sync_state() is called in a timely fashion and the
929 * put_device() is called on this device.
930 */
931static void __device_links_queue_sync_state(struct device *dev,
932 struct list_head *list)
933{
934 struct device_link *link;
935
936 if (!dev_has_sync_state(dev))
937 return;
938 if (dev->state_synced)
939 return;
940
941 list_for_each_entry(link, &dev->links.consumers, s_node) {
942 if (!(link->flags & DL_FLAG_MANAGED))
943 continue;
944 if (link->status != DL_STATE_ACTIVE)
945 return;
946 }
947
948 /*
949 * Set the flag here to avoid adding the same device to a list more
950 * than once. This can happen if new consumers get added to the device
951 * and probed before the list is flushed.
952 */
953 dev->state_synced = true;
954
955 if (WARN_ON(!list_empty(&dev->links.defer_hook)))
956 return;
957
958 get_device(dev);
959 list_add_tail(&dev->links.defer_hook, list);
960}
961
962/**
963 * device_links_flush_sync_list - Call sync_state() on a list of devices
964 * @list: List of devices to call sync_state() on
965 * @dont_lock_dev: Device for which lock is already held by the caller
966 *
967 * Calls sync_state() on all the devices that have been queued for it. This
968 * function is used in conjunction with __device_links_queue_sync_state(). The
969 * @dont_lock_dev parameter is useful when this function is called from a
970 * context where a device lock is already held.
971 */
972static void device_links_flush_sync_list(struct list_head *list,
973 struct device *dont_lock_dev)
974{
975 struct device *dev, *tmp;
976
977 list_for_each_entry_safe(dev, tmp, list, links.defer_hook) {
978 list_del_init(&dev->links.defer_hook);
979
980 if (dev != dont_lock_dev)
981 device_lock(dev);
982
983 if (dev->bus->sync_state)
984 dev->bus->sync_state(dev);
985 else if (dev->driver && dev->driver->sync_state)
986 dev->driver->sync_state(dev);
987
988 if (dev != dont_lock_dev)
989 device_unlock(dev);
990
991 put_device(dev);
992 }
993}
994
995void device_links_supplier_sync_state_pause(void)
996{
997 device_links_write_lock();
998 defer_sync_state_count++;
999 device_links_write_unlock();
1000}
1001
1002void device_links_supplier_sync_state_resume(void)
1003{
1004 struct device *dev, *tmp;
1005 LIST_HEAD(sync_list);
1006
1007 device_links_write_lock();
1008 if (!defer_sync_state_count) {
1009 WARN(true, "Unmatched sync_state pause/resume!");
1010 goto out;
1011 }
1012 defer_sync_state_count--;
1013 if (defer_sync_state_count)
1014 goto out;
1015
1016 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_hook) {
1017 /*
1018 * Delete from deferred_sync list before queuing it to
1019 * sync_list because defer_hook is used for both lists.
1020 */
1021 list_del_init(&dev->links.defer_hook);
1022 __device_links_queue_sync_state(dev, &sync_list);
1023 }
1024out:
1025 device_links_write_unlock();
1026
1027 device_links_flush_sync_list(&sync_list, NULL);
1028}
1029
1030static int sync_state_resume_initcall(void)
1031{
1032 device_links_supplier_sync_state_resume();
1033 return 0;
1034}
1035late_initcall(sync_state_resume_initcall);
1036
1037static void __device_links_supplier_defer_sync(struct device *sup)
1038{
1039 if (list_empty(&sup->links.defer_hook) && dev_has_sync_state(sup))
1040 list_add_tail(&sup->links.defer_hook, &deferred_sync);
1041}
1042
1043static void device_link_drop_managed(struct device_link *link)
1044{
1045 link->flags &= ~DL_FLAG_MANAGED;
1046 WRITE_ONCE(link->status, DL_STATE_NONE);
1047 kref_put(&link->kref, __device_link_del);
1048}
1049
1050static ssize_t waiting_for_supplier_show(struct device *dev,
1051 struct device_attribute *attr,
1052 char *buf)
1053{
1054 bool val;
1055
1056 device_lock(dev);
1057 mutex_lock(&wfs_lock);
1058 val = !list_empty(&dev->links.needs_suppliers)
1059 && dev->links.need_for_probe;
1060 mutex_unlock(&wfs_lock);
1061 device_unlock(dev);
1062 return sprintf(buf, "%u\n", val);
1063}
1064static DEVICE_ATTR_RO(waiting_for_supplier);
1065
1066/**
1067 * device_links_driver_bound - Update device links after probing its driver.
1068 * @dev: Device to update the links for.
1069 *
1070 * The probe has been successful, so update links from this device to any
1071 * consumers by changing their status to "available".
1072 *
1073 * Also change the status of @dev's links to suppliers to "active".
1074 *
1075 * Links without the DL_FLAG_MANAGED flag set are ignored.
1076 */
1077void device_links_driver_bound(struct device *dev)
1078{
1079 struct device_link *link, *ln;
1080 LIST_HEAD(sync_list);
1081
1082 /*
1083 * If a device probes successfully, it's expected to have created all
1084 * the device links it needs to or make new device links as it needs
1085 * them. So, it no longer needs to wait on any suppliers.
1086 */
1087 mutex_lock(&wfs_lock);
1088 list_del_init(&dev->links.needs_suppliers);
1089 mutex_unlock(&wfs_lock);
1090 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1091
1092 device_links_write_lock();
1093
1094 list_for_each_entry(link, &dev->links.consumers, s_node) {
1095 if (!(link->flags & DL_FLAG_MANAGED))
1096 continue;
1097
1098 /*
1099 * Links created during consumer probe may be in the "consumer
1100 * probe" state to start with if the supplier is still probing
1101 * when they are created and they may become "active" if the
1102 * consumer probe returns first. Skip them here.
1103 */
1104 if (link->status == DL_STATE_CONSUMER_PROBE ||
1105 link->status == DL_STATE_ACTIVE)
1106 continue;
1107
1108 WARN_ON(link->status != DL_STATE_DORMANT);
1109 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1110
1111 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1112 driver_deferred_probe_add(link->consumer);
1113 }
1114
1115 if (defer_sync_state_count)
1116 __device_links_supplier_defer_sync(dev);
1117 else
1118 __device_links_queue_sync_state(dev, &sync_list);
1119
1120 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1121 struct device *supplier;
1122
1123 if (!(link->flags & DL_FLAG_MANAGED))
1124 continue;
1125
1126 supplier = link->supplier;
1127 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1128 /*
1129 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1130 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1131 * save to drop the managed link completely.
1132 */
1133 device_link_drop_managed(link);
1134 } else {
1135 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1136 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1137 }
1138
1139 /*
1140 * This needs to be done even for the deleted
1141 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1142 * device link that was preventing the supplier from getting a
1143 * sync_state() call.
1144 */
1145 if (defer_sync_state_count)
1146 __device_links_supplier_defer_sync(supplier);
1147 else
1148 __device_links_queue_sync_state(supplier, &sync_list);
1149 }
1150
1151 dev->links.status = DL_DEV_DRIVER_BOUND;
1152
1153 device_links_write_unlock();
1154
1155 device_links_flush_sync_list(&sync_list, dev);
1156}
1157
1158/**
1159 * __device_links_no_driver - Update links of a device without a driver.
1160 * @dev: Device without a drvier.
1161 *
1162 * Delete all non-persistent links from this device to any suppliers.
1163 *
1164 * Persistent links stay around, but their status is changed to "available",
1165 * unless they already are in the "supplier unbind in progress" state in which
1166 * case they need not be updated.
1167 *
1168 * Links without the DL_FLAG_MANAGED flag set are ignored.
1169 */
1170static void __device_links_no_driver(struct device *dev)
1171{
1172 struct device_link *link, *ln;
1173
1174 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1175 if (!(link->flags & DL_FLAG_MANAGED))
1176 continue;
1177
1178 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1179 device_link_drop_managed(link);
1180 continue;
1181 }
1182
1183 if (link->status != DL_STATE_CONSUMER_PROBE &&
1184 link->status != DL_STATE_ACTIVE)
1185 continue;
1186
1187 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1188 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1189 } else {
1190 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1191 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1192 }
1193 }
1194
1195 dev->links.status = DL_DEV_NO_DRIVER;
1196}
1197
1198/**
1199 * device_links_no_driver - Update links after failing driver probe.
1200 * @dev: Device whose driver has just failed to probe.
1201 *
1202 * Clean up leftover links to consumers for @dev and invoke
1203 * %__device_links_no_driver() to update links to suppliers for it as
1204 * appropriate.
1205 *
1206 * Links without the DL_FLAG_MANAGED flag set are ignored.
1207 */
1208void device_links_no_driver(struct device *dev)
1209{
1210 struct device_link *link;
1211
1212 device_links_write_lock();
1213
1214 list_for_each_entry(link, &dev->links.consumers, s_node) {
1215 if (!(link->flags & DL_FLAG_MANAGED))
1216 continue;
1217
1218 /*
1219 * The probe has failed, so if the status of the link is
1220 * "consumer probe" or "active", it must have been added by
1221 * a probing consumer while this device was still probing.
1222 * Change its state to "dormant", as it represents a valid
1223 * relationship, but it is not functionally meaningful.
1224 */
1225 if (link->status == DL_STATE_CONSUMER_PROBE ||
1226 link->status == DL_STATE_ACTIVE)
1227 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1228 }
1229
1230 __device_links_no_driver(dev);
1231
1232 device_links_write_unlock();
1233}
1234
1235/**
1236 * device_links_driver_cleanup - Update links after driver removal.
1237 * @dev: Device whose driver has just gone away.
1238 *
1239 * Update links to consumers for @dev by changing their status to "dormant" and
1240 * invoke %__device_links_no_driver() to update links to suppliers for it as
1241 * appropriate.
1242 *
1243 * Links without the DL_FLAG_MANAGED flag set are ignored.
1244 */
1245void device_links_driver_cleanup(struct device *dev)
1246{
1247 struct device_link *link, *ln;
1248
1249 device_links_write_lock();
1250
1251 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1252 if (!(link->flags & DL_FLAG_MANAGED))
1253 continue;
1254
1255 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1256 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1257
1258 /*
1259 * autoremove the links between this @dev and its consumer
1260 * devices that are not active, i.e. where the link state
1261 * has moved to DL_STATE_SUPPLIER_UNBIND.
1262 */
1263 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1264 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1265 device_link_drop_managed(link);
1266
1267 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1268 }
1269
1270 list_del_init(&dev->links.defer_hook);
1271 __device_links_no_driver(dev);
1272
1273 device_links_write_unlock();
1274}
1275
1276/**
1277 * device_links_busy - Check if there are any busy links to consumers.
1278 * @dev: Device to check.
1279 *
1280 * Check each consumer of the device and return 'true' if its link's status
1281 * is one of "consumer probe" or "active" (meaning that the given consumer is
1282 * probing right now or its driver is present). Otherwise, change the link
1283 * state to "supplier unbind" to prevent the consumer from being probed
1284 * successfully going forward.
1285 *
1286 * Return 'false' if there are no probing or active consumers.
1287 *
1288 * Links without the DL_FLAG_MANAGED flag set are ignored.
1289 */
1290bool device_links_busy(struct device *dev)
1291{
1292 struct device_link *link;
1293 bool ret = false;
1294
1295 device_links_write_lock();
1296
1297 list_for_each_entry(link, &dev->links.consumers, s_node) {
1298 if (!(link->flags & DL_FLAG_MANAGED))
1299 continue;
1300
1301 if (link->status == DL_STATE_CONSUMER_PROBE
1302 || link->status == DL_STATE_ACTIVE) {
1303 ret = true;
1304 break;
1305 }
1306 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1307 }
1308
1309 dev->links.status = DL_DEV_UNBINDING;
1310
1311 device_links_write_unlock();
1312 return ret;
1313}
1314
1315/**
1316 * device_links_unbind_consumers - Force unbind consumers of the given device.
1317 * @dev: Device to unbind the consumers of.
1318 *
1319 * Walk the list of links to consumers for @dev and if any of them is in the
1320 * "consumer probe" state, wait for all device probes in progress to complete
1321 * and start over.
1322 *
1323 * If that's not the case, change the status of the link to "supplier unbind"
1324 * and check if the link was in the "active" state. If so, force the consumer
1325 * driver to unbind and start over (the consumer will not re-probe as we have
1326 * changed the state of the link already).
1327 *
1328 * Links without the DL_FLAG_MANAGED flag set are ignored.
1329 */
1330void device_links_unbind_consumers(struct device *dev)
1331{
1332 struct device_link *link;
1333
1334 start:
1335 device_links_write_lock();
1336
1337 list_for_each_entry(link, &dev->links.consumers, s_node) {
1338 enum device_link_state status;
1339
1340 if (!(link->flags & DL_FLAG_MANAGED) ||
1341 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1342 continue;
1343
1344 status = link->status;
1345 if (status == DL_STATE_CONSUMER_PROBE) {
1346 device_links_write_unlock();
1347
1348 wait_for_device_probe();
1349 goto start;
1350 }
1351 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1352 if (status == DL_STATE_ACTIVE) {
1353 struct device *consumer = link->consumer;
1354
1355 get_device(consumer);
1356
1357 device_links_write_unlock();
1358
1359 device_release_driver_internal(consumer, NULL,
1360 consumer->parent);
1361 put_device(consumer);
1362 goto start;
1363 }
1364 }
1365
1366 device_links_write_unlock();
1367}
1368
1369/**
1370 * device_links_purge - Delete existing links to other devices.
1371 * @dev: Target device.
1372 */
1373static void device_links_purge(struct device *dev)
1374{
1375 struct device_link *link, *ln;
1376
1377 if (dev->class == &devlink_class)
1378 return;
1379
1380 mutex_lock(&wfs_lock);
1381 list_del(&dev->links.needs_suppliers);
1382 mutex_unlock(&wfs_lock);
1383
1384 /*
1385 * Delete all of the remaining links from this device to any other
1386 * devices (either consumers or suppliers).
1387 */
1388 device_links_write_lock();
1389
1390 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1391 WARN_ON(link->status == DL_STATE_ACTIVE);
1392 __device_link_del(&link->kref);
1393 }
1394
1395 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1396 WARN_ON(link->status != DL_STATE_DORMANT &&
1397 link->status != DL_STATE_NONE);
1398 __device_link_del(&link->kref);
1399 }
1400
1401 device_links_write_unlock();
1402}
1403
1404static u32 fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY;
1405static int __init fw_devlink_setup(char *arg)
1406{
1407 if (!arg)
1408 return -EINVAL;
1409
1410 if (strcmp(arg, "off") == 0) {
1411 fw_devlink_flags = 0;
1412 } else if (strcmp(arg, "permissive") == 0) {
1413 fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY;
1414 } else if (strcmp(arg, "on") == 0) {
1415 fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER;
1416 } else if (strcmp(arg, "rpm") == 0) {
1417 fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER |
1418 DL_FLAG_PM_RUNTIME;
1419 }
1420 return 0;
1421}
1422early_param("fw_devlink", fw_devlink_setup);
1423
1424u32 fw_devlink_get_flags(void)
1425{
1426 return fw_devlink_flags;
1427}
1428
1429static bool fw_devlink_is_permissive(void)
1430{
1431 return fw_devlink_flags == DL_FLAG_SYNC_STATE_ONLY;
1432}
1433
1434static void fw_devlink_link_device(struct device *dev)
1435{
1436 int fw_ret;
1437
1438 if (!fw_devlink_flags)
1439 return;
1440
1441 mutex_lock(&defer_fw_devlink_lock);
1442 if (!defer_fw_devlink_count)
1443 device_link_add_missing_supplier_links();
1444
1445 /*
1446 * The device's fwnode not having add_links() doesn't affect if other
1447 * consumers can find this device as a supplier. So, this check is
1448 * intentionally placed after device_link_add_missing_supplier_links().
1449 */
1450 if (!fwnode_has_op(dev->fwnode, add_links))
1451 goto out;
1452
1453 /*
1454 * If fw_devlink is being deferred, assume all devices have mandatory
1455 * suppliers they need to link to later. Then, when the fw_devlink is
1456 * resumed, all these devices will get a chance to try and link to any
1457 * suppliers they have.
1458 */
1459 if (!defer_fw_devlink_count) {
1460 fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
1461 if (fw_ret == -ENODEV && fw_devlink_is_permissive())
1462 fw_ret = -EAGAIN;
1463 } else {
1464 fw_ret = -ENODEV;
1465 /*
1466 * defer_hook is not used to add device to deferred_sync list
1467 * until device is bound. Since deferred fw devlink also blocks
1468 * probing, same list hook can be used for deferred_fw_devlink.
1469 */
1470 list_add_tail(&dev->links.defer_hook, &deferred_fw_devlink);
1471 }
1472
1473 if (fw_ret == -ENODEV)
1474 device_link_wait_for_mandatory_supplier(dev);
1475 else if (fw_ret)
1476 device_link_wait_for_optional_supplier(dev);
1477
1478out:
1479 mutex_unlock(&defer_fw_devlink_lock);
1480}
1481
1482/**
1483 * fw_devlink_pause - Pause parsing of fwnode to create device links
1484 *
1485 * Calling this function defers any fwnode parsing to create device links until
1486 * fw_devlink_resume() is called. Both these functions are ref counted and the
1487 * caller needs to match the calls.
1488 *
1489 * While fw_devlink is paused:
1490 * - Any device that is added won't have its fwnode parsed to create device
1491 * links.
1492 * - The probe of the device will also be deferred during this period.
1493 * - Any devices that were already added, but waiting for suppliers won't be
1494 * able to link to newly added devices.
1495 *
1496 * Once fw_devlink_resume():
1497 * - All the fwnodes that was not parsed will be parsed.
1498 * - All the devices that were deferred probing will be reattempted if they
1499 * aren't waiting for any more suppliers.
1500 *
1501 * This pair of functions, is mainly meant to optimize the parsing of fwnodes
1502 * when a lot of devices that need to link to each other are added in a short
1503 * interval of time. For example, adding all the top level devices in a system.
1504 *
1505 * For example, if N devices are added and:
1506 * - All the consumers are added before their suppliers
1507 * - All the suppliers of the N devices are part of the N devices
1508 *
1509 * Then:
1510 *
1511 * - With the use of fw_devlink_pause() and fw_devlink_resume(), each device
1512 * will only need one parsing of its fwnode because it is guaranteed to find
1513 * all the supplier devices already registered and ready to link to. It won't
1514 * have to do another pass later to find one or more suppliers it couldn't
1515 * find in the first parse of the fwnode. So, we'll only need O(N) fwnode
1516 * parses.
1517 *
1518 * - Without the use of fw_devlink_pause() and fw_devlink_resume(), we would
1519 * end up doing O(N^2) parses of fwnodes because every device that's added is
1520 * guaranteed to trigger a parse of the fwnode of every device added before
1521 * it. This O(N^2) parse is made worse by the fact that when a fwnode of a
1522 * device is parsed, all it descendant devices might need to have their
1523 * fwnodes parsed too (even if the devices themselves aren't added).
1524 */
1525void fw_devlink_pause(void)
1526{
1527 mutex_lock(&defer_fw_devlink_lock);
1528 defer_fw_devlink_count++;
1529 mutex_unlock(&defer_fw_devlink_lock);
1530}
1531
1532/** fw_devlink_resume - Resume parsing of fwnode to create device links
1533 *
1534 * This function is used in conjunction with fw_devlink_pause() and is ref
1535 * counted. See documentation for fw_devlink_pause() for more details.
1536 */
1537void fw_devlink_resume(void)
1538{
1539 struct device *dev, *tmp;
1540 LIST_HEAD(probe_list);
1541
1542 mutex_lock(&defer_fw_devlink_lock);
1543 if (!defer_fw_devlink_count) {
1544 WARN(true, "Unmatched fw_devlink pause/resume!");
1545 goto out;
1546 }
1547
1548 defer_fw_devlink_count--;
1549 if (defer_fw_devlink_count)
1550 goto out;
1551
1552 device_link_add_missing_supplier_links();
1553 list_splice_tail_init(&deferred_fw_devlink, &probe_list);
1554out:
1555 mutex_unlock(&defer_fw_devlink_lock);
1556
1557 /*
1558 * bus_probe_device() can cause new devices to get added and they'll
1559 * try to grab defer_fw_devlink_lock. So, this needs to be done outside
1560 * the defer_fw_devlink_lock.
1561 */
1562 list_for_each_entry_safe(dev, tmp, &probe_list, links.defer_hook) {
1563 list_del_init(&dev->links.defer_hook);
1564 bus_probe_device(dev);
1565 }
1566}
1567/* Device links support end. */
1568
1569int (*platform_notify)(struct device *dev) = NULL;
1570int (*platform_notify_remove)(struct device *dev) = NULL;
1571static struct kobject *dev_kobj;
1572struct kobject *sysfs_dev_char_kobj;
1573struct kobject *sysfs_dev_block_kobj;
1574
1575static DEFINE_MUTEX(device_hotplug_lock);
1576
1577void lock_device_hotplug(void)
1578{
1579 mutex_lock(&device_hotplug_lock);
1580}
1581
1582void unlock_device_hotplug(void)
1583{
1584 mutex_unlock(&device_hotplug_lock);
1585}
1586
1587int lock_device_hotplug_sysfs(void)
1588{
1589 if (mutex_trylock(&device_hotplug_lock))
1590 return 0;
1591
1592 /* Avoid busy looping (5 ms of sleep should do). */
1593 msleep(5);
1594 return restart_syscall();
1595}
1596
1597#ifdef CONFIG_BLOCK
1598static inline int device_is_not_partition(struct device *dev)
1599{
1600 return !(dev->type == &part_type);
1601}
1602#else
1603static inline int device_is_not_partition(struct device *dev)
1604{
1605 return 1;
1606}
1607#endif
1608
1609static int
1610device_platform_notify(struct device *dev, enum kobject_action action)
1611{
1612 int ret;
1613
1614 ret = acpi_platform_notify(dev, action);
1615 if (ret)
1616 return ret;
1617
1618 ret = software_node_notify(dev, action);
1619 if (ret)
1620 return ret;
1621
1622 if (platform_notify && action == KOBJ_ADD)
1623 platform_notify(dev);
1624 else if (platform_notify_remove && action == KOBJ_REMOVE)
1625 platform_notify_remove(dev);
1626 return 0;
1627}
1628
1629/**
1630 * dev_driver_string - Return a device's driver name, if at all possible
1631 * @dev: struct device to get the name of
1632 *
1633 * Will return the device's driver's name if it is bound to a device. If
1634 * the device is not bound to a driver, it will return the name of the bus
1635 * it is attached to. If it is not attached to a bus either, an empty
1636 * string will be returned.
1637 */
1638const char *dev_driver_string(const struct device *dev)
1639{
1640 struct device_driver *drv;
1641
1642 /* dev->driver can change to NULL underneath us because of unbinding,
1643 * so be careful about accessing it. dev->bus and dev->class should
1644 * never change once they are set, so they don't need special care.
1645 */
1646 drv = READ_ONCE(dev->driver);
1647 return drv ? drv->name :
1648 (dev->bus ? dev->bus->name :
1649 (dev->class ? dev->class->name : ""));
1650}
1651EXPORT_SYMBOL(dev_driver_string);
1652
1653#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
1654
1655static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
1656 char *buf)
1657{
1658 struct device_attribute *dev_attr = to_dev_attr(attr);
1659 struct device *dev = kobj_to_dev(kobj);
1660 ssize_t ret = -EIO;
1661
1662 if (dev_attr->show)
1663 ret = dev_attr->show(dev, dev_attr, buf);
1664 if (ret >= (ssize_t)PAGE_SIZE) {
1665 printk("dev_attr_show: %pS returned bad count\n",
1666 dev_attr->show);
1667 }
1668 return ret;
1669}
1670
1671static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
1672 const char *buf, size_t count)
1673{
1674 struct device_attribute *dev_attr = to_dev_attr(attr);
1675 struct device *dev = kobj_to_dev(kobj);
1676 ssize_t ret = -EIO;
1677
1678 if (dev_attr->store)
1679 ret = dev_attr->store(dev, dev_attr, buf, count);
1680 return ret;
1681}
1682
1683static const struct sysfs_ops dev_sysfs_ops = {
1684 .show = dev_attr_show,
1685 .store = dev_attr_store,
1686};
1687
1688#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
1689
1690ssize_t device_store_ulong(struct device *dev,
1691 struct device_attribute *attr,
1692 const char *buf, size_t size)
1693{
1694 struct dev_ext_attribute *ea = to_ext_attr(attr);
1695 int ret;
1696 unsigned long new;
1697
1698 ret = kstrtoul(buf, 0, &new);
1699 if (ret)
1700 return ret;
1701 *(unsigned long *)(ea->var) = new;
1702 /* Always return full write size even if we didn't consume all */
1703 return size;
1704}
1705EXPORT_SYMBOL_GPL(device_store_ulong);
1706
1707ssize_t device_show_ulong(struct device *dev,
1708 struct device_attribute *attr,
1709 char *buf)
1710{
1711 struct dev_ext_attribute *ea = to_ext_attr(attr);
1712 return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
1713}
1714EXPORT_SYMBOL_GPL(device_show_ulong);
1715
1716ssize_t device_store_int(struct device *dev,
1717 struct device_attribute *attr,
1718 const char *buf, size_t size)
1719{
1720 struct dev_ext_attribute *ea = to_ext_attr(attr);
1721 int ret;
1722 long new;
1723
1724 ret = kstrtol(buf, 0, &new);
1725 if (ret)
1726 return ret;
1727
1728 if (new > INT_MAX || new < INT_MIN)
1729 return -EINVAL;
1730 *(int *)(ea->var) = new;
1731 /* Always return full write size even if we didn't consume all */
1732 return size;
1733}
1734EXPORT_SYMBOL_GPL(device_store_int);
1735
1736ssize_t device_show_int(struct device *dev,
1737 struct device_attribute *attr,
1738 char *buf)
1739{
1740 struct dev_ext_attribute *ea = to_ext_attr(attr);
1741
1742 return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
1743}
1744EXPORT_SYMBOL_GPL(device_show_int);
1745
1746ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
1747 const char *buf, size_t size)
1748{
1749 struct dev_ext_attribute *ea = to_ext_attr(attr);
1750
1751 if (strtobool(buf, ea->var) < 0)
1752 return -EINVAL;
1753
1754 return size;
1755}
1756EXPORT_SYMBOL_GPL(device_store_bool);
1757
1758ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
1759 char *buf)
1760{
1761 struct dev_ext_attribute *ea = to_ext_attr(attr);
1762
1763 return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
1764}
1765EXPORT_SYMBOL_GPL(device_show_bool);
1766
1767/**
1768 * device_release - free device structure.
1769 * @kobj: device's kobject.
1770 *
1771 * This is called once the reference count for the object
1772 * reaches 0. We forward the call to the device's release
1773 * method, which should handle actually freeing the structure.
1774 */
1775static void device_release(struct kobject *kobj)
1776{
1777 struct device *dev = kobj_to_dev(kobj);
1778 struct device_private *p = dev->p;
1779
1780 /*
1781 * Some platform devices are driven without driver attached
1782 * and managed resources may have been acquired. Make sure
1783 * all resources are released.
1784 *
1785 * Drivers still can add resources into device after device
1786 * is deleted but alive, so release devres here to avoid
1787 * possible memory leak.
1788 */
1789 devres_release_all(dev);
1790
1791 if (dev->release)
1792 dev->release(dev);
1793 else if (dev->type && dev->type->release)
1794 dev->type->release(dev);
1795 else if (dev->class && dev->class->dev_release)
1796 dev->class->dev_release(dev);
1797 else
1798 WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
1799 dev_name(dev));
1800 kfree(p);
1801}
1802
1803static const void *device_namespace(struct kobject *kobj)
1804{
1805 struct device *dev = kobj_to_dev(kobj);
1806 const void *ns = NULL;
1807
1808 if (dev->class && dev->class->ns_type)
1809 ns = dev->class->namespace(dev);
1810
1811 return ns;
1812}
1813
1814static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
1815{
1816 struct device *dev = kobj_to_dev(kobj);
1817
1818 if (dev->class && dev->class->get_ownership)
1819 dev->class->get_ownership(dev, uid, gid);
1820}
1821
1822static struct kobj_type device_ktype = {
1823 .release = device_release,
1824 .sysfs_ops = &dev_sysfs_ops,
1825 .namespace = device_namespace,
1826 .get_ownership = device_get_ownership,
1827};
1828
1829
1830static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
1831{
1832 struct kobj_type *ktype = get_ktype(kobj);
1833
1834 if (ktype == &device_ktype) {
1835 struct device *dev = kobj_to_dev(kobj);
1836 if (dev->bus)
1837 return 1;
1838 if (dev->class)
1839 return 1;
1840 }
1841 return 0;
1842}
1843
1844static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
1845{
1846 struct device *dev = kobj_to_dev(kobj);
1847
1848 if (dev->bus)
1849 return dev->bus->name;
1850 if (dev->class)
1851 return dev->class->name;
1852 return NULL;
1853}
1854
1855static int dev_uevent(struct kset *kset, struct kobject *kobj,
1856 struct kobj_uevent_env *env)
1857{
1858 struct device *dev = kobj_to_dev(kobj);
1859 int retval = 0;
1860
1861 /* add device node properties if present */
1862 if (MAJOR(dev->devt)) {
1863 const char *tmp;
1864 const char *name;
1865 umode_t mode = 0;
1866 kuid_t uid = GLOBAL_ROOT_UID;
1867 kgid_t gid = GLOBAL_ROOT_GID;
1868
1869 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
1870 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
1871 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
1872 if (name) {
1873 add_uevent_var(env, "DEVNAME=%s", name);
1874 if (mode)
1875 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
1876 if (!uid_eq(uid, GLOBAL_ROOT_UID))
1877 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
1878 if (!gid_eq(gid, GLOBAL_ROOT_GID))
1879 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
1880 kfree(tmp);
1881 }
1882 }
1883
1884 if (dev->type && dev->type->name)
1885 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
1886
1887 if (dev->driver)
1888 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
1889
1890 /* Add common DT information about the device */
1891 of_device_uevent(dev, env);
1892
1893 /* have the bus specific function add its stuff */
1894 if (dev->bus && dev->bus->uevent) {
1895 retval = dev->bus->uevent(dev, env);
1896 if (retval)
1897 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
1898 dev_name(dev), __func__, retval);
1899 }
1900
1901 /* have the class specific function add its stuff */
1902 if (dev->class && dev->class->dev_uevent) {
1903 retval = dev->class->dev_uevent(dev, env);
1904 if (retval)
1905 pr_debug("device: '%s': %s: class uevent() "
1906 "returned %d\n", dev_name(dev),
1907 __func__, retval);
1908 }
1909
1910 /* have the device type specific function add its stuff */
1911 if (dev->type && dev->type->uevent) {
1912 retval = dev->type->uevent(dev, env);
1913 if (retval)
1914 pr_debug("device: '%s': %s: dev_type uevent() "
1915 "returned %d\n", dev_name(dev),
1916 __func__, retval);
1917 }
1918
1919 return retval;
1920}
1921
1922static const struct kset_uevent_ops device_uevent_ops = {
1923 .filter = dev_uevent_filter,
1924 .name = dev_uevent_name,
1925 .uevent = dev_uevent,
1926};
1927
1928static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
1929 char *buf)
1930{
1931 struct kobject *top_kobj;
1932 struct kset *kset;
1933 struct kobj_uevent_env *env = NULL;
1934 int i;
1935 size_t count = 0;
1936 int retval;
1937
1938 /* search the kset, the device belongs to */
1939 top_kobj = &dev->kobj;
1940 while (!top_kobj->kset && top_kobj->parent)
1941 top_kobj = top_kobj->parent;
1942 if (!top_kobj->kset)
1943 goto out;
1944
1945 kset = top_kobj->kset;
1946 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
1947 goto out;
1948
1949 /* respect filter */
1950 if (kset->uevent_ops && kset->uevent_ops->filter)
1951 if (!kset->uevent_ops->filter(kset, &dev->kobj))
1952 goto out;
1953
1954 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
1955 if (!env)
1956 return -ENOMEM;
1957
1958 /* let the kset specific function add its keys */
1959 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
1960 if (retval)
1961 goto out;
1962
1963 /* copy keys to file */
1964 for (i = 0; i < env->envp_idx; i++)
1965 count += sprintf(&buf[count], "%s\n", env->envp[i]);
1966out:
1967 kfree(env);
1968 return count;
1969}
1970
1971static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
1972 const char *buf, size_t count)
1973{
1974 int rc;
1975
1976 rc = kobject_synth_uevent(&dev->kobj, buf, count);
1977
1978 if (rc) {
1979 dev_err(dev, "uevent: failed to send synthetic uevent\n");
1980 return rc;
1981 }
1982
1983 return count;
1984}
1985static DEVICE_ATTR_RW(uevent);
1986
1987static ssize_t online_show(struct device *dev, struct device_attribute *attr,
1988 char *buf)
1989{
1990 bool val;
1991
1992 device_lock(dev);
1993 val = !dev->offline;
1994 device_unlock(dev);
1995 return sprintf(buf, "%u\n", val);
1996}
1997
1998static ssize_t online_store(struct device *dev, struct device_attribute *attr,
1999 const char *buf, size_t count)
2000{
2001 bool val;
2002 int ret;
2003
2004 ret = strtobool(buf, &val);
2005 if (ret < 0)
2006 return ret;
2007
2008 ret = lock_device_hotplug_sysfs();
2009 if (ret)
2010 return ret;
2011
2012 ret = val ? device_online(dev) : device_offline(dev);
2013 unlock_device_hotplug();
2014 return ret < 0 ? ret : count;
2015}
2016static DEVICE_ATTR_RW(online);
2017
2018int device_add_groups(struct device *dev, const struct attribute_group **groups)
2019{
2020 return sysfs_create_groups(&dev->kobj, groups);
2021}
2022EXPORT_SYMBOL_GPL(device_add_groups);
2023
2024void device_remove_groups(struct device *dev,
2025 const struct attribute_group **groups)
2026{
2027 sysfs_remove_groups(&dev->kobj, groups);
2028}
2029EXPORT_SYMBOL_GPL(device_remove_groups);
2030
2031union device_attr_group_devres {
2032 const struct attribute_group *group;
2033 const struct attribute_group **groups;
2034};
2035
2036static int devm_attr_group_match(struct device *dev, void *res, void *data)
2037{
2038 return ((union device_attr_group_devres *)res)->group == data;
2039}
2040
2041static void devm_attr_group_remove(struct device *dev, void *res)
2042{
2043 union device_attr_group_devres *devres = res;
2044 const struct attribute_group *group = devres->group;
2045
2046 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2047 sysfs_remove_group(&dev->kobj, group);
2048}
2049
2050static void devm_attr_groups_remove(struct device *dev, void *res)
2051{
2052 union device_attr_group_devres *devres = res;
2053 const struct attribute_group **groups = devres->groups;
2054
2055 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2056 sysfs_remove_groups(&dev->kobj, groups);
2057}
2058
2059/**
2060 * devm_device_add_group - given a device, create a managed attribute group
2061 * @dev: The device to create the group for
2062 * @grp: The attribute group to create
2063 *
2064 * This function creates a group for the first time. It will explicitly
2065 * warn and error if any of the attribute files being created already exist.
2066 *
2067 * Returns 0 on success or error code on failure.
2068 */
2069int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2070{
2071 union device_attr_group_devres *devres;
2072 int error;
2073
2074 devres = devres_alloc(devm_attr_group_remove,
2075 sizeof(*devres), GFP_KERNEL);
2076 if (!devres)
2077 return -ENOMEM;
2078
2079 error = sysfs_create_group(&dev->kobj, grp);
2080 if (error) {
2081 devres_free(devres);
2082 return error;
2083 }
2084
2085 devres->group = grp;
2086 devres_add(dev, devres);
2087 return 0;
2088}
2089EXPORT_SYMBOL_GPL(devm_device_add_group);
2090
2091/**
2092 * devm_device_remove_group: remove a managed group from a device
2093 * @dev: device to remove the group from
2094 * @grp: group to remove
2095 *
2096 * This function removes a group of attributes from a device. The attributes
2097 * previously have to have been created for this group, otherwise it will fail.
2098 */
2099void devm_device_remove_group(struct device *dev,
2100 const struct attribute_group *grp)
2101{
2102 WARN_ON(devres_release(dev, devm_attr_group_remove,
2103 devm_attr_group_match,
2104 /* cast away const */ (void *)grp));
2105}
2106EXPORT_SYMBOL_GPL(devm_device_remove_group);
2107
2108/**
2109 * devm_device_add_groups - create a bunch of managed attribute groups
2110 * @dev: The device to create the group for
2111 * @groups: The attribute groups to create, NULL terminated
2112 *
2113 * This function creates a bunch of managed attribute groups. If an error
2114 * occurs when creating a group, all previously created groups will be
2115 * removed, unwinding everything back to the original state when this
2116 * function was called. It will explicitly warn and error if any of the
2117 * attribute files being created already exist.
2118 *
2119 * Returns 0 on success or error code from sysfs_create_group on failure.
2120 */
2121int devm_device_add_groups(struct device *dev,
2122 const struct attribute_group **groups)
2123{
2124 union device_attr_group_devres *devres;
2125 int error;
2126
2127 devres = devres_alloc(devm_attr_groups_remove,
2128 sizeof(*devres), GFP_KERNEL);
2129 if (!devres)
2130 return -ENOMEM;
2131
2132 error = sysfs_create_groups(&dev->kobj, groups);
2133 if (error) {
2134 devres_free(devres);
2135 return error;
2136 }
2137
2138 devres->groups = groups;
2139 devres_add(dev, devres);
2140 return 0;
2141}
2142EXPORT_SYMBOL_GPL(devm_device_add_groups);
2143
2144/**
2145 * devm_device_remove_groups - remove a list of managed groups
2146 *
2147 * @dev: The device for the groups to be removed from
2148 * @groups: NULL terminated list of groups to be removed
2149 *
2150 * If groups is not NULL, remove the specified groups from the device.
2151 */
2152void devm_device_remove_groups(struct device *dev,
2153 const struct attribute_group **groups)
2154{
2155 WARN_ON(devres_release(dev, devm_attr_groups_remove,
2156 devm_attr_group_match,
2157 /* cast away const */ (void *)groups));
2158}
2159EXPORT_SYMBOL_GPL(devm_device_remove_groups);
2160
2161static int device_add_attrs(struct device *dev)
2162{
2163 struct class *class = dev->class;
2164 const struct device_type *type = dev->type;
2165 int error;
2166
2167 if (class) {
2168 error = device_add_groups(dev, class->dev_groups);
2169 if (error)
2170 return error;
2171 }
2172
2173 if (type) {
2174 error = device_add_groups(dev, type->groups);
2175 if (error)
2176 goto err_remove_class_groups;
2177 }
2178
2179 error = device_add_groups(dev, dev->groups);
2180 if (error)
2181 goto err_remove_type_groups;
2182
2183 if (device_supports_offline(dev) && !dev->offline_disabled) {
2184 error = device_create_file(dev, &dev_attr_online);
2185 if (error)
2186 goto err_remove_dev_groups;
2187 }
2188
2189 if (fw_devlink_flags && !fw_devlink_is_permissive()) {
2190 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2191 if (error)
2192 goto err_remove_dev_online;
2193 }
2194
2195 return 0;
2196
2197 err_remove_dev_online:
2198 device_remove_file(dev, &dev_attr_online);
2199 err_remove_dev_groups:
2200 device_remove_groups(dev, dev->groups);
2201 err_remove_type_groups:
2202 if (type)
2203 device_remove_groups(dev, type->groups);
2204 err_remove_class_groups:
2205 if (class)
2206 device_remove_groups(dev, class->dev_groups);
2207
2208 return error;
2209}
2210
2211static void device_remove_attrs(struct device *dev)
2212{
2213 struct class *class = dev->class;
2214 const struct device_type *type = dev->type;
2215
2216 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2217 device_remove_file(dev, &dev_attr_online);
2218 device_remove_groups(dev, dev->groups);
2219
2220 if (type)
2221 device_remove_groups(dev, type->groups);
2222
2223 if (class)
2224 device_remove_groups(dev, class->dev_groups);
2225}
2226
2227static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2228 char *buf)
2229{
2230 return print_dev_t(buf, dev->devt);
2231}
2232static DEVICE_ATTR_RO(dev);
2233
2234/* /sys/devices/ */
2235struct kset *devices_kset;
2236
2237/**
2238 * devices_kset_move_before - Move device in the devices_kset's list.
2239 * @deva: Device to move.
2240 * @devb: Device @deva should come before.
2241 */
2242static void devices_kset_move_before(struct device *deva, struct device *devb)
2243{
2244 if (!devices_kset)
2245 return;
2246 pr_debug("devices_kset: Moving %s before %s\n",
2247 dev_name(deva), dev_name(devb));
2248 spin_lock(&devices_kset->list_lock);
2249 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2250 spin_unlock(&devices_kset->list_lock);
2251}
2252
2253/**
2254 * devices_kset_move_after - Move device in the devices_kset's list.
2255 * @deva: Device to move
2256 * @devb: Device @deva should come after.
2257 */
2258static void devices_kset_move_after(struct device *deva, struct device *devb)
2259{
2260 if (!devices_kset)
2261 return;
2262 pr_debug("devices_kset: Moving %s after %s\n",
2263 dev_name(deva), dev_name(devb));
2264 spin_lock(&devices_kset->list_lock);
2265 list_move(&deva->kobj.entry, &devb->kobj.entry);
2266 spin_unlock(&devices_kset->list_lock);
2267}
2268
2269/**
2270 * devices_kset_move_last - move the device to the end of devices_kset's list.
2271 * @dev: device to move
2272 */
2273void devices_kset_move_last(struct device *dev)
2274{
2275 if (!devices_kset)
2276 return;
2277 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2278 spin_lock(&devices_kset->list_lock);
2279 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2280 spin_unlock(&devices_kset->list_lock);
2281}
2282
2283/**
2284 * device_create_file - create sysfs attribute file for device.
2285 * @dev: device.
2286 * @attr: device attribute descriptor.
2287 */
2288int device_create_file(struct device *dev,
2289 const struct device_attribute *attr)
2290{
2291 int error = 0;
2292
2293 if (dev) {
2294 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2295 "Attribute %s: write permission without 'store'\n",
2296 attr->attr.name);
2297 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2298 "Attribute %s: read permission without 'show'\n",
2299 attr->attr.name);
2300 error = sysfs_create_file(&dev->kobj, &attr->attr);
2301 }
2302
2303 return error;
2304}
2305EXPORT_SYMBOL_GPL(device_create_file);
2306
2307/**
2308 * device_remove_file - remove sysfs attribute file.
2309 * @dev: device.
2310 * @attr: device attribute descriptor.
2311 */
2312void device_remove_file(struct device *dev,
2313 const struct device_attribute *attr)
2314{
2315 if (dev)
2316 sysfs_remove_file(&dev->kobj, &attr->attr);
2317}
2318EXPORT_SYMBOL_GPL(device_remove_file);
2319
2320/**
2321 * device_remove_file_self - remove sysfs attribute file from its own method.
2322 * @dev: device.
2323 * @attr: device attribute descriptor.
2324 *
2325 * See kernfs_remove_self() for details.
2326 */
2327bool device_remove_file_self(struct device *dev,
2328 const struct device_attribute *attr)
2329{
2330 if (dev)
2331 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2332 else
2333 return false;
2334}
2335EXPORT_SYMBOL_GPL(device_remove_file_self);
2336
2337/**
2338 * device_create_bin_file - create sysfs binary attribute file for device.
2339 * @dev: device.
2340 * @attr: device binary attribute descriptor.
2341 */
2342int device_create_bin_file(struct device *dev,
2343 const struct bin_attribute *attr)
2344{
2345 int error = -EINVAL;
2346 if (dev)
2347 error = sysfs_create_bin_file(&dev->kobj, attr);
2348 return error;
2349}
2350EXPORT_SYMBOL_GPL(device_create_bin_file);
2351
2352/**
2353 * device_remove_bin_file - remove sysfs binary attribute file
2354 * @dev: device.
2355 * @attr: device binary attribute descriptor.
2356 */
2357void device_remove_bin_file(struct device *dev,
2358 const struct bin_attribute *attr)
2359{
2360 if (dev)
2361 sysfs_remove_bin_file(&dev->kobj, attr);
2362}
2363EXPORT_SYMBOL_GPL(device_remove_bin_file);
2364
2365static void klist_children_get(struct klist_node *n)
2366{
2367 struct device_private *p = to_device_private_parent(n);
2368 struct device *dev = p->device;
2369
2370 get_device(dev);
2371}
2372
2373static void klist_children_put(struct klist_node *n)
2374{
2375 struct device_private *p = to_device_private_parent(n);
2376 struct device *dev = p->device;
2377
2378 put_device(dev);
2379}
2380
2381/**
2382 * device_initialize - init device structure.
2383 * @dev: device.
2384 *
2385 * This prepares the device for use by other layers by initializing
2386 * its fields.
2387 * It is the first half of device_register(), if called by
2388 * that function, though it can also be called separately, so one
2389 * may use @dev's fields. In particular, get_device()/put_device()
2390 * may be used for reference counting of @dev after calling this
2391 * function.
2392 *
2393 * All fields in @dev must be initialized by the caller to 0, except
2394 * for those explicitly set to some other value. The simplest
2395 * approach is to use kzalloc() to allocate the structure containing
2396 * @dev.
2397 *
2398 * NOTE: Use put_device() to give up your reference instead of freeing
2399 * @dev directly once you have called this function.
2400 */
2401void device_initialize(struct device *dev)
2402{
2403 dev->kobj.kset = devices_kset;
2404 kobject_init(&dev->kobj, &device_ktype);
2405 INIT_LIST_HEAD(&dev->dma_pools);
2406 mutex_init(&dev->mutex);
2407#ifdef CONFIG_PROVE_LOCKING
2408 mutex_init(&dev->lockdep_mutex);
2409#endif
2410 lockdep_set_novalidate_class(&dev->mutex);
2411 spin_lock_init(&dev->devres_lock);
2412 INIT_LIST_HEAD(&dev->devres_head);
2413 device_pm_init(dev);
2414 set_dev_node(dev, -1);
2415#ifdef CONFIG_GENERIC_MSI_IRQ
2416 INIT_LIST_HEAD(&dev->msi_list);
2417#endif
2418 INIT_LIST_HEAD(&dev->links.consumers);
2419 INIT_LIST_HEAD(&dev->links.suppliers);
2420 INIT_LIST_HEAD(&dev->links.needs_suppliers);
2421 INIT_LIST_HEAD(&dev->links.defer_hook);
2422 dev->links.status = DL_DEV_NO_DRIVER;
2423}
2424EXPORT_SYMBOL_GPL(device_initialize);
2425
2426struct kobject *virtual_device_parent(struct device *dev)
2427{
2428 static struct kobject *virtual_dir = NULL;
2429
2430 if (!virtual_dir)
2431 virtual_dir = kobject_create_and_add("virtual",
2432 &devices_kset->kobj);
2433
2434 return virtual_dir;
2435}
2436
2437struct class_dir {
2438 struct kobject kobj;
2439 struct class *class;
2440};
2441
2442#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2443
2444static void class_dir_release(struct kobject *kobj)
2445{
2446 struct class_dir *dir = to_class_dir(kobj);
2447 kfree(dir);
2448}
2449
2450static const
2451struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
2452{
2453 struct class_dir *dir = to_class_dir(kobj);
2454 return dir->class->ns_type;
2455}
2456
2457static struct kobj_type class_dir_ktype = {
2458 .release = class_dir_release,
2459 .sysfs_ops = &kobj_sysfs_ops,
2460 .child_ns_type = class_dir_child_ns_type
2461};
2462
2463static struct kobject *
2464class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
2465{
2466 struct class_dir *dir;
2467 int retval;
2468
2469 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
2470 if (!dir)
2471 return ERR_PTR(-ENOMEM);
2472
2473 dir->class = class;
2474 kobject_init(&dir->kobj, &class_dir_ktype);
2475
2476 dir->kobj.kset = &class->p->glue_dirs;
2477
2478 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
2479 if (retval < 0) {
2480 kobject_put(&dir->kobj);
2481 return ERR_PTR(retval);
2482 }
2483 return &dir->kobj;
2484}
2485
2486static DEFINE_MUTEX(gdp_mutex);
2487
2488static struct kobject *get_device_parent(struct device *dev,
2489 struct device *parent)
2490{
2491 if (dev->class) {
2492 struct kobject *kobj = NULL;
2493 struct kobject *parent_kobj;
2494 struct kobject *k;
2495
2496#ifdef CONFIG_BLOCK
2497 /* block disks show up in /sys/block */
2498 if (sysfs_deprecated && dev->class == &block_class) {
2499 if (parent && parent->class == &block_class)
2500 return &parent->kobj;
2501 return &block_class.p->subsys.kobj;
2502 }
2503#endif
2504
2505 /*
2506 * If we have no parent, we live in "virtual".
2507 * Class-devices with a non class-device as parent, live
2508 * in a "glue" directory to prevent namespace collisions.
2509 */
2510 if (parent == NULL)
2511 parent_kobj = virtual_device_parent(dev);
2512 else if (parent->class && !dev->class->ns_type)
2513 return &parent->kobj;
2514 else
2515 parent_kobj = &parent->kobj;
2516
2517 mutex_lock(&gdp_mutex);
2518
2519 /* find our class-directory at the parent and reference it */
2520 spin_lock(&dev->class->p->glue_dirs.list_lock);
2521 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
2522 if (k->parent == parent_kobj) {
2523 kobj = kobject_get(k);
2524 break;
2525 }
2526 spin_unlock(&dev->class->p->glue_dirs.list_lock);
2527 if (kobj) {
2528 mutex_unlock(&gdp_mutex);
2529 return kobj;
2530 }
2531
2532 /* or create a new class-directory at the parent device */
2533 k = class_dir_create_and_add(dev->class, parent_kobj);
2534 /* do not emit an uevent for this simple "glue" directory */
2535 mutex_unlock(&gdp_mutex);
2536 return k;
2537 }
2538
2539 /* subsystems can specify a default root directory for their devices */
2540 if (!parent && dev->bus && dev->bus->dev_root)
2541 return &dev->bus->dev_root->kobj;
2542
2543 if (parent)
2544 return &parent->kobj;
2545 return NULL;
2546}
2547
2548static inline bool live_in_glue_dir(struct kobject *kobj,
2549 struct device *dev)
2550{
2551 if (!kobj || !dev->class ||
2552 kobj->kset != &dev->class->p->glue_dirs)
2553 return false;
2554 return true;
2555}
2556
2557static inline struct kobject *get_glue_dir(struct device *dev)
2558{
2559 return dev->kobj.parent;
2560}
2561
2562/*
2563 * make sure cleaning up dir as the last step, we need to make
2564 * sure .release handler of kobject is run with holding the
2565 * global lock
2566 */
2567static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
2568{
2569 unsigned int ref;
2570
2571 /* see if we live in a "glue" directory */
2572 if (!live_in_glue_dir(glue_dir, dev))
2573 return;
2574
2575 mutex_lock(&gdp_mutex);
2576 /**
2577 * There is a race condition between removing glue directory
2578 * and adding a new device under the glue directory.
2579 *
2580 * CPU1: CPU2:
2581 *
2582 * device_add()
2583 * get_device_parent()
2584 * class_dir_create_and_add()
2585 * kobject_add_internal()
2586 * create_dir() // create glue_dir
2587 *
2588 * device_add()
2589 * get_device_parent()
2590 * kobject_get() // get glue_dir
2591 *
2592 * device_del()
2593 * cleanup_glue_dir()
2594 * kobject_del(glue_dir)
2595 *
2596 * kobject_add()
2597 * kobject_add_internal()
2598 * create_dir() // in glue_dir
2599 * sysfs_create_dir_ns()
2600 * kernfs_create_dir_ns(sd)
2601 *
2602 * sysfs_remove_dir() // glue_dir->sd=NULL
2603 * sysfs_put() // free glue_dir->sd
2604 *
2605 * // sd is freed
2606 * kernfs_new_node(sd)
2607 * kernfs_get(glue_dir)
2608 * kernfs_add_one()
2609 * kernfs_put()
2610 *
2611 * Before CPU1 remove last child device under glue dir, if CPU2 add
2612 * a new device under glue dir, the glue_dir kobject reference count
2613 * will be increase to 2 in kobject_get(k). And CPU2 has been called
2614 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
2615 * and sysfs_put(). This result in glue_dir->sd is freed.
2616 *
2617 * Then the CPU2 will see a stale "empty" but still potentially used
2618 * glue dir around in kernfs_new_node().
2619 *
2620 * In order to avoid this happening, we also should make sure that
2621 * kernfs_node for glue_dir is released in CPU1 only when refcount
2622 * for glue_dir kobj is 1.
2623 */
2624 ref = kref_read(&glue_dir->kref);
2625 if (!kobject_has_children(glue_dir) && !--ref)
2626 kobject_del(glue_dir);
2627 kobject_put(glue_dir);
2628 mutex_unlock(&gdp_mutex);
2629}
2630
2631static int device_add_class_symlinks(struct device *dev)
2632{
2633 struct device_node *of_node = dev_of_node(dev);
2634 int error;
2635
2636 if (of_node) {
2637 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
2638 if (error)
2639 dev_warn(dev, "Error %d creating of_node link\n",error);
2640 /* An error here doesn't warrant bringing down the device */
2641 }
2642
2643 if (!dev->class)
2644 return 0;
2645
2646 error = sysfs_create_link(&dev->kobj,
2647 &dev->class->p->subsys.kobj,
2648 "subsystem");
2649 if (error)
2650 goto out_devnode;
2651
2652 if (dev->parent && device_is_not_partition(dev)) {
2653 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
2654 "device");
2655 if (error)
2656 goto out_subsys;
2657 }
2658
2659#ifdef CONFIG_BLOCK
2660 /* /sys/block has directories and does not need symlinks */
2661 if (sysfs_deprecated && dev->class == &block_class)
2662 return 0;
2663#endif
2664
2665 /* link in the class directory pointing to the device */
2666 error = sysfs_create_link(&dev->class->p->subsys.kobj,
2667 &dev->kobj, dev_name(dev));
2668 if (error)
2669 goto out_device;
2670
2671 return 0;
2672
2673out_device:
2674 sysfs_remove_link(&dev->kobj, "device");
2675
2676out_subsys:
2677 sysfs_remove_link(&dev->kobj, "subsystem");
2678out_devnode:
2679 sysfs_remove_link(&dev->kobj, "of_node");
2680 return error;
2681}
2682
2683static void device_remove_class_symlinks(struct device *dev)
2684{
2685 if (dev_of_node(dev))
2686 sysfs_remove_link(&dev->kobj, "of_node");
2687
2688 if (!dev->class)
2689 return;
2690
2691 if (dev->parent && device_is_not_partition(dev))
2692 sysfs_remove_link(&dev->kobj, "device");
2693 sysfs_remove_link(&dev->kobj, "subsystem");
2694#ifdef CONFIG_BLOCK
2695 if (sysfs_deprecated && dev->class == &block_class)
2696 return;
2697#endif
2698 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
2699}
2700
2701/**
2702 * dev_set_name - set a device name
2703 * @dev: device
2704 * @fmt: format string for the device's name
2705 */
2706int dev_set_name(struct device *dev, const char *fmt, ...)
2707{
2708 va_list vargs;
2709 int err;
2710
2711 va_start(vargs, fmt);
2712 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
2713 va_end(vargs);
2714 return err;
2715}
2716EXPORT_SYMBOL_GPL(dev_set_name);
2717
2718/**
2719 * device_to_dev_kobj - select a /sys/dev/ directory for the device
2720 * @dev: device
2721 *
2722 * By default we select char/ for new entries. Setting class->dev_obj
2723 * to NULL prevents an entry from being created. class->dev_kobj must
2724 * be set (or cleared) before any devices are registered to the class
2725 * otherwise device_create_sys_dev_entry() and
2726 * device_remove_sys_dev_entry() will disagree about the presence of
2727 * the link.
2728 */
2729static struct kobject *device_to_dev_kobj(struct device *dev)
2730{
2731 struct kobject *kobj;
2732
2733 if (dev->class)
2734 kobj = dev->class->dev_kobj;
2735 else
2736 kobj = sysfs_dev_char_kobj;
2737
2738 return kobj;
2739}
2740
2741static int device_create_sys_dev_entry(struct device *dev)
2742{
2743 struct kobject *kobj = device_to_dev_kobj(dev);
2744 int error = 0;
2745 char devt_str[15];
2746
2747 if (kobj) {
2748 format_dev_t(devt_str, dev->devt);
2749 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
2750 }
2751
2752 return error;
2753}
2754
2755static void device_remove_sys_dev_entry(struct device *dev)
2756{
2757 struct kobject *kobj = device_to_dev_kobj(dev);
2758 char devt_str[15];
2759
2760 if (kobj) {
2761 format_dev_t(devt_str, dev->devt);
2762 sysfs_remove_link(kobj, devt_str);
2763 }
2764}
2765
2766static int device_private_init(struct device *dev)
2767{
2768 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
2769 if (!dev->p)
2770 return -ENOMEM;
2771 dev->p->device = dev;
2772 klist_init(&dev->p->klist_children, klist_children_get,
2773 klist_children_put);
2774 INIT_LIST_HEAD(&dev->p->deferred_probe);
2775 return 0;
2776}
2777
2778/**
2779 * device_add - add device to device hierarchy.
2780 * @dev: device.
2781 *
2782 * This is part 2 of device_register(), though may be called
2783 * separately _iff_ device_initialize() has been called separately.
2784 *
2785 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
2786 * to the global and sibling lists for the device, then
2787 * adds it to the other relevant subsystems of the driver model.
2788 *
2789 * Do not call this routine or device_register() more than once for
2790 * any device structure. The driver model core is not designed to work
2791 * with devices that get unregistered and then spring back to life.
2792 * (Among other things, it's very hard to guarantee that all references
2793 * to the previous incarnation of @dev have been dropped.) Allocate
2794 * and register a fresh new struct device instead.
2795 *
2796 * NOTE: _Never_ directly free @dev after calling this function, even
2797 * if it returned an error! Always use put_device() to give up your
2798 * reference instead.
2799 *
2800 * Rule of thumb is: if device_add() succeeds, you should call
2801 * device_del() when you want to get rid of it. If device_add() has
2802 * *not* succeeded, use *only* put_device() to drop the reference
2803 * count.
2804 */
2805int device_add(struct device *dev)
2806{
2807 struct device *parent;
2808 struct kobject *kobj;
2809 struct class_interface *class_intf;
2810 int error = -EINVAL;
2811 struct kobject *glue_dir = NULL;
2812
2813 dev = get_device(dev);
2814 if (!dev)
2815 goto done;
2816
2817 if (!dev->p) {
2818 error = device_private_init(dev);
2819 if (error)
2820 goto done;
2821 }
2822
2823 /*
2824 * for statically allocated devices, which should all be converted
2825 * some day, we need to initialize the name. We prevent reading back
2826 * the name, and force the use of dev_name()
2827 */
2828 if (dev->init_name) {
2829 dev_set_name(dev, "%s", dev->init_name);
2830 dev->init_name = NULL;
2831 }
2832
2833 /* subsystems can specify simple device enumeration */
2834 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
2835 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
2836
2837 if (!dev_name(dev)) {
2838 error = -EINVAL;
2839 goto name_error;
2840 }
2841
2842 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
2843
2844 parent = get_device(dev->parent);
2845 kobj = get_device_parent(dev, parent);
2846 if (IS_ERR(kobj)) {
2847 error = PTR_ERR(kobj);
2848 goto parent_error;
2849 }
2850 if (kobj)
2851 dev->kobj.parent = kobj;
2852
2853 /* use parent numa_node */
2854 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
2855 set_dev_node(dev, dev_to_node(parent));
2856
2857 /* first, register with generic layer. */
2858 /* we require the name to be set before, and pass NULL */
2859 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
2860 if (error) {
2861 glue_dir = get_glue_dir(dev);
2862 goto Error;
2863 }
2864
2865 /* notify platform of device entry */
2866 error = device_platform_notify(dev, KOBJ_ADD);
2867 if (error)
2868 goto platform_error;
2869
2870 error = device_create_file(dev, &dev_attr_uevent);
2871 if (error)
2872 goto attrError;
2873
2874 error = device_add_class_symlinks(dev);
2875 if (error)
2876 goto SymlinkError;
2877 error = device_add_attrs(dev);
2878 if (error)
2879 goto AttrsError;
2880 error = bus_add_device(dev);
2881 if (error)
2882 goto BusError;
2883 error = dpm_sysfs_add(dev);
2884 if (error)
2885 goto DPMError;
2886 device_pm_add(dev);
2887
2888 if (MAJOR(dev->devt)) {
2889 error = device_create_file(dev, &dev_attr_dev);
2890 if (error)
2891 goto DevAttrError;
2892
2893 error = device_create_sys_dev_entry(dev);
2894 if (error)
2895 goto SysEntryError;
2896
2897 devtmpfs_create_node(dev);
2898 }
2899
2900 /* Notify clients of device addition. This call must come
2901 * after dpm_sysfs_add() and before kobject_uevent().
2902 */
2903 if (dev->bus)
2904 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
2905 BUS_NOTIFY_ADD_DEVICE, dev);
2906
2907 kobject_uevent(&dev->kobj, KOBJ_ADD);
2908
2909 /*
2910 * Check if any of the other devices (consumers) have been waiting for
2911 * this device (supplier) to be added so that they can create a device
2912 * link to it.
2913 *
2914 * This needs to happen after device_pm_add() because device_link_add()
2915 * requires the supplier be registered before it's called.
2916 *
2917 * But this also needs to happen before bus_probe_device() to make sure
2918 * waiting consumers can link to it before the driver is bound to the
2919 * device and the driver sync_state callback is called for this device.
2920 */
2921 if (dev->fwnode && !dev->fwnode->dev) {
2922 dev->fwnode->dev = dev;
2923 fw_devlink_link_device(dev);
2924 }
2925
2926 bus_probe_device(dev);
2927 if (parent)
2928 klist_add_tail(&dev->p->knode_parent,
2929 &parent->p->klist_children);
2930
2931 if (dev->class) {
2932 mutex_lock(&dev->class->p->mutex);
2933 /* tie the class to the device */
2934 klist_add_tail(&dev->p->knode_class,
2935 &dev->class->p->klist_devices);
2936
2937 /* notify any interfaces that the device is here */
2938 list_for_each_entry(class_intf,
2939 &dev->class->p->interfaces, node)
2940 if (class_intf->add_dev)
2941 class_intf->add_dev(dev, class_intf);
2942 mutex_unlock(&dev->class->p->mutex);
2943 }
2944done:
2945 put_device(dev);
2946 return error;
2947 SysEntryError:
2948 if (MAJOR(dev->devt))
2949 device_remove_file(dev, &dev_attr_dev);
2950 DevAttrError:
2951 device_pm_remove(dev);
2952 dpm_sysfs_remove(dev);
2953 DPMError:
2954 bus_remove_device(dev);
2955 BusError:
2956 device_remove_attrs(dev);
2957 AttrsError:
2958 device_remove_class_symlinks(dev);
2959 SymlinkError:
2960 device_remove_file(dev, &dev_attr_uevent);
2961 attrError:
2962 device_platform_notify(dev, KOBJ_REMOVE);
2963platform_error:
2964 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
2965 glue_dir = get_glue_dir(dev);
2966 kobject_del(&dev->kobj);
2967 Error:
2968 cleanup_glue_dir(dev, glue_dir);
2969parent_error:
2970 put_device(parent);
2971name_error:
2972 kfree(dev->p);
2973 dev->p = NULL;
2974 goto done;
2975}
2976EXPORT_SYMBOL_GPL(device_add);
2977
2978/**
2979 * device_register - register a device with the system.
2980 * @dev: pointer to the device structure
2981 *
2982 * This happens in two clean steps - initialize the device
2983 * and add it to the system. The two steps can be called
2984 * separately, but this is the easiest and most common.
2985 * I.e. you should only call the two helpers separately if
2986 * have a clearly defined need to use and refcount the device
2987 * before it is added to the hierarchy.
2988 *
2989 * For more information, see the kerneldoc for device_initialize()
2990 * and device_add().
2991 *
2992 * NOTE: _Never_ directly free @dev after calling this function, even
2993 * if it returned an error! Always use put_device() to give up the
2994 * reference initialized in this function instead.
2995 */
2996int device_register(struct device *dev)
2997{
2998 device_initialize(dev);
2999 return device_add(dev);
3000}
3001EXPORT_SYMBOL_GPL(device_register);
3002
3003/**
3004 * get_device - increment reference count for device.
3005 * @dev: device.
3006 *
3007 * This simply forwards the call to kobject_get(), though
3008 * we do take care to provide for the case that we get a NULL
3009 * pointer passed in.
3010 */
3011struct device *get_device(struct device *dev)
3012{
3013 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3014}
3015EXPORT_SYMBOL_GPL(get_device);
3016
3017/**
3018 * put_device - decrement reference count.
3019 * @dev: device in question.
3020 */
3021void put_device(struct device *dev)
3022{
3023 /* might_sleep(); */
3024 if (dev)
3025 kobject_put(&dev->kobj);
3026}
3027EXPORT_SYMBOL_GPL(put_device);
3028
3029bool kill_device(struct device *dev)
3030{
3031 /*
3032 * Require the device lock and set the "dead" flag to guarantee that
3033 * the update behavior is consistent with the other bitfields near
3034 * it and that we cannot have an asynchronous probe routine trying
3035 * to run while we are tearing out the bus/class/sysfs from
3036 * underneath the device.
3037 */
3038 lockdep_assert_held(&dev->mutex);
3039
3040 if (dev->p->dead)
3041 return false;
3042 dev->p->dead = true;
3043 return true;
3044}
3045EXPORT_SYMBOL_GPL(kill_device);
3046
3047/**
3048 * device_del - delete device from system.
3049 * @dev: device.
3050 *
3051 * This is the first part of the device unregistration
3052 * sequence. This removes the device from the lists we control
3053 * from here, has it removed from the other driver model
3054 * subsystems it was added to in device_add(), and removes it
3055 * from the kobject hierarchy.
3056 *
3057 * NOTE: this should be called manually _iff_ device_add() was
3058 * also called manually.
3059 */
3060void device_del(struct device *dev)
3061{
3062 struct device *parent = dev->parent;
3063 struct kobject *glue_dir = NULL;
3064 struct class_interface *class_intf;
3065
3066 device_lock(dev);
3067 kill_device(dev);
3068 device_unlock(dev);
3069
3070 if (dev->fwnode && dev->fwnode->dev == dev)
3071 dev->fwnode->dev = NULL;
3072
3073 /* Notify clients of device removal. This call must come
3074 * before dpm_sysfs_remove().
3075 */
3076 if (dev->bus)
3077 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3078 BUS_NOTIFY_DEL_DEVICE, dev);
3079
3080 dpm_sysfs_remove(dev);
3081 if (parent)
3082 klist_del(&dev->p->knode_parent);
3083 if (MAJOR(dev->devt)) {
3084 devtmpfs_delete_node(dev);
3085 device_remove_sys_dev_entry(dev);
3086 device_remove_file(dev, &dev_attr_dev);
3087 }
3088 if (dev->class) {
3089 device_remove_class_symlinks(dev);
3090
3091 mutex_lock(&dev->class->p->mutex);
3092 /* notify any interfaces that the device is now gone */
3093 list_for_each_entry(class_intf,
3094 &dev->class->p->interfaces, node)
3095 if (class_intf->remove_dev)
3096 class_intf->remove_dev(dev, class_intf);
3097 /* remove the device from the class list */
3098 klist_del(&dev->p->knode_class);
3099 mutex_unlock(&dev->class->p->mutex);
3100 }
3101 device_remove_file(dev, &dev_attr_uevent);
3102 device_remove_attrs(dev);
3103 bus_remove_device(dev);
3104 device_pm_remove(dev);
3105 driver_deferred_probe_del(dev);
3106 device_platform_notify(dev, KOBJ_REMOVE);
3107 device_remove_properties(dev);
3108 device_links_purge(dev);
3109
3110 if (dev->bus)
3111 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3112 BUS_NOTIFY_REMOVED_DEVICE, dev);
3113 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3114 glue_dir = get_glue_dir(dev);
3115 kobject_del(&dev->kobj);
3116 cleanup_glue_dir(dev, glue_dir);
3117 put_device(parent);
3118}
3119EXPORT_SYMBOL_GPL(device_del);
3120
3121/**
3122 * device_unregister - unregister device from system.
3123 * @dev: device going away.
3124 *
3125 * We do this in two parts, like we do device_register(). First,
3126 * we remove it from all the subsystems with device_del(), then
3127 * we decrement the reference count via put_device(). If that
3128 * is the final reference count, the device will be cleaned up
3129 * via device_release() above. Otherwise, the structure will
3130 * stick around until the final reference to the device is dropped.
3131 */
3132void device_unregister(struct device *dev)
3133{
3134 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3135 device_del(dev);
3136 put_device(dev);
3137}
3138EXPORT_SYMBOL_GPL(device_unregister);
3139
3140static struct device *prev_device(struct klist_iter *i)
3141{
3142 struct klist_node *n = klist_prev(i);
3143 struct device *dev = NULL;
3144 struct device_private *p;
3145
3146 if (n) {
3147 p = to_device_private_parent(n);
3148 dev = p->device;
3149 }
3150 return dev;
3151}
3152
3153static struct device *next_device(struct klist_iter *i)
3154{
3155 struct klist_node *n = klist_next(i);
3156 struct device *dev = NULL;
3157 struct device_private *p;
3158
3159 if (n) {
3160 p = to_device_private_parent(n);
3161 dev = p->device;
3162 }
3163 return dev;
3164}
3165
3166/**
3167 * device_get_devnode - path of device node file
3168 * @dev: device
3169 * @mode: returned file access mode
3170 * @uid: returned file owner
3171 * @gid: returned file group
3172 * @tmp: possibly allocated string
3173 *
3174 * Return the relative path of a possible device node.
3175 * Non-default names may need to allocate a memory to compose
3176 * a name. This memory is returned in tmp and needs to be
3177 * freed by the caller.
3178 */
3179const char *device_get_devnode(struct device *dev,
3180 umode_t *mode, kuid_t *uid, kgid_t *gid,
3181 const char **tmp)
3182{
3183 char *s;
3184
3185 *tmp = NULL;
3186
3187 /* the device type may provide a specific name */
3188 if (dev->type && dev->type->devnode)
3189 *tmp = dev->type->devnode(dev, mode, uid, gid);
3190 if (*tmp)
3191 return *tmp;
3192
3193 /* the class may provide a specific name */
3194 if (dev->class && dev->class->devnode)
3195 *tmp = dev->class->devnode(dev, mode);
3196 if (*tmp)
3197 return *tmp;
3198
3199 /* return name without allocation, tmp == NULL */
3200 if (strchr(dev_name(dev), '!') == NULL)
3201 return dev_name(dev);
3202
3203 /* replace '!' in the name with '/' */
3204 s = kstrdup(dev_name(dev), GFP_KERNEL);
3205 if (!s)
3206 return NULL;
3207 strreplace(s, '!', '/');
3208 return *tmp = s;
3209}
3210
3211/**
3212 * device_for_each_child - device child iterator.
3213 * @parent: parent struct device.
3214 * @fn: function to be called for each device.
3215 * @data: data for the callback.
3216 *
3217 * Iterate over @parent's child devices, and call @fn for each,
3218 * passing it @data.
3219 *
3220 * We check the return of @fn each time. If it returns anything
3221 * other than 0, we break out and return that value.
3222 */
3223int device_for_each_child(struct device *parent, void *data,
3224 int (*fn)(struct device *dev, void *data))
3225{
3226 struct klist_iter i;
3227 struct device *child;
3228 int error = 0;
3229
3230 if (!parent->p)
3231 return 0;
3232
3233 klist_iter_init(&parent->p->klist_children, &i);
3234 while (!error && (child = next_device(&i)))
3235 error = fn(child, data);
3236 klist_iter_exit(&i);
3237 return error;
3238}
3239EXPORT_SYMBOL_GPL(device_for_each_child);
3240
3241/**
3242 * device_for_each_child_reverse - device child iterator in reversed order.
3243 * @parent: parent struct device.
3244 * @fn: function to be called for each device.
3245 * @data: data for the callback.
3246 *
3247 * Iterate over @parent's child devices, and call @fn for each,
3248 * passing it @data.
3249 *
3250 * We check the return of @fn each time. If it returns anything
3251 * other than 0, we break out and return that value.
3252 */
3253int device_for_each_child_reverse(struct device *parent, void *data,
3254 int (*fn)(struct device *dev, void *data))
3255{
3256 struct klist_iter i;
3257 struct device *child;
3258 int error = 0;
3259
3260 if (!parent->p)
3261 return 0;
3262
3263 klist_iter_init(&parent->p->klist_children, &i);
3264 while ((child = prev_device(&i)) && !error)
3265 error = fn(child, data);
3266 klist_iter_exit(&i);
3267 return error;
3268}
3269EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3270
3271/**
3272 * device_find_child - device iterator for locating a particular device.
3273 * @parent: parent struct device
3274 * @match: Callback function to check device
3275 * @data: Data to pass to match function
3276 *
3277 * This is similar to the device_for_each_child() function above, but it
3278 * returns a reference to a device that is 'found' for later use, as
3279 * determined by the @match callback.
3280 *
3281 * The callback should return 0 if the device doesn't match and non-zero
3282 * if it does. If the callback returns non-zero and a reference to the
3283 * current device can be obtained, this function will return to the caller
3284 * and not iterate over any more devices.
3285 *
3286 * NOTE: you will need to drop the reference with put_device() after use.
3287 */
3288struct device *device_find_child(struct device *parent, void *data,
3289 int (*match)(struct device *dev, void *data))
3290{
3291 struct klist_iter i;
3292 struct device *child;
3293
3294 if (!parent)
3295 return NULL;
3296
3297 klist_iter_init(&parent->p->klist_children, &i);
3298 while ((child = next_device(&i)))
3299 if (match(child, data) && get_device(child))
3300 break;
3301 klist_iter_exit(&i);
3302 return child;
3303}
3304EXPORT_SYMBOL_GPL(device_find_child);
3305
3306/**
3307 * device_find_child_by_name - device iterator for locating a child device.
3308 * @parent: parent struct device
3309 * @name: name of the child device
3310 *
3311 * This is similar to the device_find_child() function above, but it
3312 * returns a reference to a device that has the name @name.
3313 *
3314 * NOTE: you will need to drop the reference with put_device() after use.
3315 */
3316struct device *device_find_child_by_name(struct device *parent,
3317 const char *name)
3318{
3319 struct klist_iter i;
3320 struct device *child;
3321
3322 if (!parent)
3323 return NULL;
3324
3325 klist_iter_init(&parent->p->klist_children, &i);
3326 while ((child = next_device(&i)))
3327 if (!strcmp(dev_name(child), name) && get_device(child))
3328 break;
3329 klist_iter_exit(&i);
3330 return child;
3331}
3332EXPORT_SYMBOL_GPL(device_find_child_by_name);
3333
3334int __init devices_init(void)
3335{
3336 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3337 if (!devices_kset)
3338 return -ENOMEM;
3339 dev_kobj = kobject_create_and_add("dev", NULL);
3340 if (!dev_kobj)
3341 goto dev_kobj_err;
3342 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3343 if (!sysfs_dev_block_kobj)
3344 goto block_kobj_err;
3345 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3346 if (!sysfs_dev_char_kobj)
3347 goto char_kobj_err;
3348
3349 return 0;
3350
3351 char_kobj_err:
3352 kobject_put(sysfs_dev_block_kobj);
3353 block_kobj_err:
3354 kobject_put(dev_kobj);
3355 dev_kobj_err:
3356 kset_unregister(devices_kset);
3357 return -ENOMEM;
3358}
3359
3360static int device_check_offline(struct device *dev, void *not_used)
3361{
3362 int ret;
3363
3364 ret = device_for_each_child(dev, NULL, device_check_offline);
3365 if (ret)
3366 return ret;
3367
3368 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3369}
3370
3371/**
3372 * device_offline - Prepare the device for hot-removal.
3373 * @dev: Device to be put offline.
3374 *
3375 * Execute the device bus type's .offline() callback, if present, to prepare
3376 * the device for a subsequent hot-removal. If that succeeds, the device must
3377 * not be used until either it is removed or its bus type's .online() callback
3378 * is executed.
3379 *
3380 * Call under device_hotplug_lock.
3381 */
3382int device_offline(struct device *dev)
3383{
3384 int ret;
3385
3386 if (dev->offline_disabled)
3387 return -EPERM;
3388
3389 ret = device_for_each_child(dev, NULL, device_check_offline);
3390 if (ret)
3391 return ret;
3392
3393 device_lock(dev);
3394 if (device_supports_offline(dev)) {
3395 if (dev->offline) {
3396 ret = 1;
3397 } else {
3398 ret = dev->bus->offline(dev);
3399 if (!ret) {
3400 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3401 dev->offline = true;
3402 }
3403 }
3404 }
3405 device_unlock(dev);
3406
3407 return ret;
3408}
3409
3410/**
3411 * device_online - Put the device back online after successful device_offline().
3412 * @dev: Device to be put back online.
3413 *
3414 * If device_offline() has been successfully executed for @dev, but the device
3415 * has not been removed subsequently, execute its bus type's .online() callback
3416 * to indicate that the device can be used again.
3417 *
3418 * Call under device_hotplug_lock.
3419 */
3420int device_online(struct device *dev)
3421{
3422 int ret = 0;
3423
3424 device_lock(dev);
3425 if (device_supports_offline(dev)) {
3426 if (dev->offline) {
3427 ret = dev->bus->online(dev);
3428 if (!ret) {
3429 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
3430 dev->offline = false;
3431 }
3432 } else {
3433 ret = 1;
3434 }
3435 }
3436 device_unlock(dev);
3437
3438 return ret;
3439}
3440
3441struct root_device {
3442 struct device dev;
3443 struct module *owner;
3444};
3445
3446static inline struct root_device *to_root_device(struct device *d)
3447{
3448 return container_of(d, struct root_device, dev);
3449}
3450
3451static void root_device_release(struct device *dev)
3452{
3453 kfree(to_root_device(dev));
3454}
3455
3456/**
3457 * __root_device_register - allocate and register a root device
3458 * @name: root device name
3459 * @owner: owner module of the root device, usually THIS_MODULE
3460 *
3461 * This function allocates a root device and registers it
3462 * using device_register(). In order to free the returned
3463 * device, use root_device_unregister().
3464 *
3465 * Root devices are dummy devices which allow other devices
3466 * to be grouped under /sys/devices. Use this function to
3467 * allocate a root device and then use it as the parent of
3468 * any device which should appear under /sys/devices/{name}
3469 *
3470 * The /sys/devices/{name} directory will also contain a
3471 * 'module' symlink which points to the @owner directory
3472 * in sysfs.
3473 *
3474 * Returns &struct device pointer on success, or ERR_PTR() on error.
3475 *
3476 * Note: You probably want to use root_device_register().
3477 */
3478struct device *__root_device_register(const char *name, struct module *owner)
3479{
3480 struct root_device *root;
3481 int err = -ENOMEM;
3482
3483 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
3484 if (!root)
3485 return ERR_PTR(err);
3486
3487 err = dev_set_name(&root->dev, "%s", name);
3488 if (err) {
3489 kfree(root);
3490 return ERR_PTR(err);
3491 }
3492
3493 root->dev.release = root_device_release;
3494
3495 err = device_register(&root->dev);
3496 if (err) {
3497 put_device(&root->dev);
3498 return ERR_PTR(err);
3499 }
3500
3501#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
3502 if (owner) {
3503 struct module_kobject *mk = &owner->mkobj;
3504
3505 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
3506 if (err) {
3507 device_unregister(&root->dev);
3508 return ERR_PTR(err);
3509 }
3510 root->owner = owner;
3511 }
3512#endif
3513
3514 return &root->dev;
3515}
3516EXPORT_SYMBOL_GPL(__root_device_register);
3517
3518/**
3519 * root_device_unregister - unregister and free a root device
3520 * @dev: device going away
3521 *
3522 * This function unregisters and cleans up a device that was created by
3523 * root_device_register().
3524 */
3525void root_device_unregister(struct device *dev)
3526{
3527 struct root_device *root = to_root_device(dev);
3528
3529 if (root->owner)
3530 sysfs_remove_link(&root->dev.kobj, "module");
3531
3532 device_unregister(dev);
3533}
3534EXPORT_SYMBOL_GPL(root_device_unregister);
3535
3536
3537static void device_create_release(struct device *dev)
3538{
3539 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3540 kfree(dev);
3541}
3542
3543static __printf(6, 0) struct device *
3544device_create_groups_vargs(struct class *class, struct device *parent,
3545 dev_t devt, void *drvdata,
3546 const struct attribute_group **groups,
3547 const char *fmt, va_list args)
3548{
3549 struct device *dev = NULL;
3550 int retval = -ENODEV;
3551
3552 if (class == NULL || IS_ERR(class))
3553 goto error;
3554
3555 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3556 if (!dev) {
3557 retval = -ENOMEM;
3558 goto error;
3559 }
3560
3561 device_initialize(dev);
3562 dev->devt = devt;
3563 dev->class = class;
3564 dev->parent = parent;
3565 dev->groups = groups;
3566 dev->release = device_create_release;
3567 dev_set_drvdata(dev, drvdata);
3568
3569 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
3570 if (retval)
3571 goto error;
3572
3573 retval = device_add(dev);
3574 if (retval)
3575 goto error;
3576
3577 return dev;
3578
3579error:
3580 put_device(dev);
3581 return ERR_PTR(retval);
3582}
3583
3584/**
3585 * device_create - creates a device and registers it with sysfs
3586 * @class: pointer to the struct class that this device should be registered to
3587 * @parent: pointer to the parent struct device of this new device, if any
3588 * @devt: the dev_t for the char device to be added
3589 * @drvdata: the data to be added to the device for callbacks
3590 * @fmt: string for the device's name
3591 *
3592 * This function can be used by char device classes. A struct device
3593 * will be created in sysfs, registered to the specified class.
3594 *
3595 * A "dev" file will be created, showing the dev_t for the device, if
3596 * the dev_t is not 0,0.
3597 * If a pointer to a parent struct device is passed in, the newly created
3598 * struct device will be a child of that device in sysfs.
3599 * The pointer to the struct device will be returned from the call.
3600 * Any further sysfs files that might be required can be created using this
3601 * pointer.
3602 *
3603 * Returns &struct device pointer on success, or ERR_PTR() on error.
3604 *
3605 * Note: the struct class passed to this function must have previously
3606 * been created with a call to class_create().
3607 */
3608struct device *device_create(struct class *class, struct device *parent,
3609 dev_t devt, void *drvdata, const char *fmt, ...)
3610{
3611 va_list vargs;
3612 struct device *dev;
3613
3614 va_start(vargs, fmt);
3615 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
3616 fmt, vargs);
3617 va_end(vargs);
3618 return dev;
3619}
3620EXPORT_SYMBOL_GPL(device_create);
3621
3622/**
3623 * device_create_with_groups - creates a device and registers it with sysfs
3624 * @class: pointer to the struct class that this device should be registered to
3625 * @parent: pointer to the parent struct device of this new device, if any
3626 * @devt: the dev_t for the char device to be added
3627 * @drvdata: the data to be added to the device for callbacks
3628 * @groups: NULL-terminated list of attribute groups to be created
3629 * @fmt: string for the device's name
3630 *
3631 * This function can be used by char device classes. A struct device
3632 * will be created in sysfs, registered to the specified class.
3633 * Additional attributes specified in the groups parameter will also
3634 * be created automatically.
3635 *
3636 * A "dev" file will be created, showing the dev_t for the device, if
3637 * the dev_t is not 0,0.
3638 * If a pointer to a parent struct device is passed in, the newly created
3639 * struct device will be a child of that device in sysfs.
3640 * The pointer to the struct device will be returned from the call.
3641 * Any further sysfs files that might be required can be created using this
3642 * pointer.
3643 *
3644 * Returns &struct device pointer on success, or ERR_PTR() on error.
3645 *
3646 * Note: the struct class passed to this function must have previously
3647 * been created with a call to class_create().
3648 */
3649struct device *device_create_with_groups(struct class *class,
3650 struct device *parent, dev_t devt,
3651 void *drvdata,
3652 const struct attribute_group **groups,
3653 const char *fmt, ...)
3654{
3655 va_list vargs;
3656 struct device *dev;
3657
3658 va_start(vargs, fmt);
3659 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
3660 fmt, vargs);
3661 va_end(vargs);
3662 return dev;
3663}
3664EXPORT_SYMBOL_GPL(device_create_with_groups);
3665
3666/**
3667 * device_destroy - removes a device that was created with device_create()
3668 * @class: pointer to the struct class that this device was registered with
3669 * @devt: the dev_t of the device that was previously registered
3670 *
3671 * This call unregisters and cleans up a device that was created with a
3672 * call to device_create().
3673 */
3674void device_destroy(struct class *class, dev_t devt)
3675{
3676 struct device *dev;
3677
3678 dev = class_find_device_by_devt(class, devt);
3679 if (dev) {
3680 put_device(dev);
3681 device_unregister(dev);
3682 }
3683}
3684EXPORT_SYMBOL_GPL(device_destroy);
3685
3686/**
3687 * device_rename - renames a device
3688 * @dev: the pointer to the struct device to be renamed
3689 * @new_name: the new name of the device
3690 *
3691 * It is the responsibility of the caller to provide mutual
3692 * exclusion between two different calls of device_rename
3693 * on the same device to ensure that new_name is valid and
3694 * won't conflict with other devices.
3695 *
3696 * Note: Don't call this function. Currently, the networking layer calls this
3697 * function, but that will change. The following text from Kay Sievers offers
3698 * some insight:
3699 *
3700 * Renaming devices is racy at many levels, symlinks and other stuff are not
3701 * replaced atomically, and you get a "move" uevent, but it's not easy to
3702 * connect the event to the old and new device. Device nodes are not renamed at
3703 * all, there isn't even support for that in the kernel now.
3704 *
3705 * In the meantime, during renaming, your target name might be taken by another
3706 * driver, creating conflicts. Or the old name is taken directly after you
3707 * renamed it -- then you get events for the same DEVPATH, before you even see
3708 * the "move" event. It's just a mess, and nothing new should ever rely on
3709 * kernel device renaming. Besides that, it's not even implemented now for
3710 * other things than (driver-core wise very simple) network devices.
3711 *
3712 * We are currently about to change network renaming in udev to completely
3713 * disallow renaming of devices in the same namespace as the kernel uses,
3714 * because we can't solve the problems properly, that arise with swapping names
3715 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
3716 * be allowed to some other name than eth[0-9]*, for the aforementioned
3717 * reasons.
3718 *
3719 * Make up a "real" name in the driver before you register anything, or add
3720 * some other attributes for userspace to find the device, or use udev to add
3721 * symlinks -- but never rename kernel devices later, it's a complete mess. We
3722 * don't even want to get into that and try to implement the missing pieces in
3723 * the core. We really have other pieces to fix in the driver core mess. :)
3724 */
3725int device_rename(struct device *dev, const char *new_name)
3726{
3727 struct kobject *kobj = &dev->kobj;
3728 char *old_device_name = NULL;
3729 int error;
3730
3731 dev = get_device(dev);
3732 if (!dev)
3733 return -EINVAL;
3734
3735 dev_dbg(dev, "renaming to %s\n", new_name);
3736
3737 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
3738 if (!old_device_name) {
3739 error = -ENOMEM;
3740 goto out;
3741 }
3742
3743 if (dev->class) {
3744 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
3745 kobj, old_device_name,
3746 new_name, kobject_namespace(kobj));
3747 if (error)
3748 goto out;
3749 }
3750
3751 error = kobject_rename(kobj, new_name);
3752 if (error)
3753 goto out;
3754
3755out:
3756 put_device(dev);
3757
3758 kfree(old_device_name);
3759
3760 return error;
3761}
3762EXPORT_SYMBOL_GPL(device_rename);
3763
3764static int device_move_class_links(struct device *dev,
3765 struct device *old_parent,
3766 struct device *new_parent)
3767{
3768 int error = 0;
3769
3770 if (old_parent)
3771 sysfs_remove_link(&dev->kobj, "device");
3772 if (new_parent)
3773 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
3774 "device");
3775 return error;
3776}
3777
3778/**
3779 * device_move - moves a device to a new parent
3780 * @dev: the pointer to the struct device to be moved
3781 * @new_parent: the new parent of the device (can be NULL)
3782 * @dpm_order: how to reorder the dpm_list
3783 */
3784int device_move(struct device *dev, struct device *new_parent,
3785 enum dpm_order dpm_order)
3786{
3787 int error;
3788 struct device *old_parent;
3789 struct kobject *new_parent_kobj;
3790
3791 dev = get_device(dev);
3792 if (!dev)
3793 return -EINVAL;
3794
3795 device_pm_lock();
3796 new_parent = get_device(new_parent);
3797 new_parent_kobj = get_device_parent(dev, new_parent);
3798 if (IS_ERR(new_parent_kobj)) {
3799 error = PTR_ERR(new_parent_kobj);
3800 put_device(new_parent);
3801 goto out;
3802 }
3803
3804 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
3805 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
3806 error = kobject_move(&dev->kobj, new_parent_kobj);
3807 if (error) {
3808 cleanup_glue_dir(dev, new_parent_kobj);
3809 put_device(new_parent);
3810 goto out;
3811 }
3812 old_parent = dev->parent;
3813 dev->parent = new_parent;
3814 if (old_parent)
3815 klist_remove(&dev->p->knode_parent);
3816 if (new_parent) {
3817 klist_add_tail(&dev->p->knode_parent,
3818 &new_parent->p->klist_children);
3819 set_dev_node(dev, dev_to_node(new_parent));
3820 }
3821
3822 if (dev->class) {
3823 error = device_move_class_links(dev, old_parent, new_parent);
3824 if (error) {
3825 /* We ignore errors on cleanup since we're hosed anyway... */
3826 device_move_class_links(dev, new_parent, old_parent);
3827 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
3828 if (new_parent)
3829 klist_remove(&dev->p->knode_parent);
3830 dev->parent = old_parent;
3831 if (old_parent) {
3832 klist_add_tail(&dev->p->knode_parent,
3833 &old_parent->p->klist_children);
3834 set_dev_node(dev, dev_to_node(old_parent));
3835 }
3836 }
3837 cleanup_glue_dir(dev, new_parent_kobj);
3838 put_device(new_parent);
3839 goto out;
3840 }
3841 }
3842 switch (dpm_order) {
3843 case DPM_ORDER_NONE:
3844 break;
3845 case DPM_ORDER_DEV_AFTER_PARENT:
3846 device_pm_move_after(dev, new_parent);
3847 devices_kset_move_after(dev, new_parent);
3848 break;
3849 case DPM_ORDER_PARENT_BEFORE_DEV:
3850 device_pm_move_before(new_parent, dev);
3851 devices_kset_move_before(new_parent, dev);
3852 break;
3853 case DPM_ORDER_DEV_LAST:
3854 device_pm_move_last(dev);
3855 devices_kset_move_last(dev);
3856 break;
3857 }
3858
3859 put_device(old_parent);
3860out:
3861 device_pm_unlock();
3862 put_device(dev);
3863 return error;
3864}
3865EXPORT_SYMBOL_GPL(device_move);
3866
3867static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
3868 kgid_t kgid)
3869{
3870 struct kobject *kobj = &dev->kobj;
3871 struct class *class = dev->class;
3872 const struct device_type *type = dev->type;
3873 int error;
3874
3875 if (class) {
3876 /*
3877 * Change the device groups of the device class for @dev to
3878 * @kuid/@kgid.
3879 */
3880 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
3881 kgid);
3882 if (error)
3883 return error;
3884 }
3885
3886 if (type) {
3887 /*
3888 * Change the device groups of the device type for @dev to
3889 * @kuid/@kgid.
3890 */
3891 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
3892 kgid);
3893 if (error)
3894 return error;
3895 }
3896
3897 /* Change the device groups of @dev to @kuid/@kgid. */
3898 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
3899 if (error)
3900 return error;
3901
3902 if (device_supports_offline(dev) && !dev->offline_disabled) {
3903 /* Change online device attributes of @dev to @kuid/@kgid. */
3904 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
3905 kuid, kgid);
3906 if (error)
3907 return error;
3908 }
3909
3910 return 0;
3911}
3912
3913/**
3914 * device_change_owner - change the owner of an existing device.
3915 * @dev: device.
3916 * @kuid: new owner's kuid
3917 * @kgid: new owner's kgid
3918 *
3919 * This changes the owner of @dev and its corresponding sysfs entries to
3920 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
3921 * core.
3922 *
3923 * Returns 0 on success or error code on failure.
3924 */
3925int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
3926{
3927 int error;
3928 struct kobject *kobj = &dev->kobj;
3929
3930 dev = get_device(dev);
3931 if (!dev)
3932 return -EINVAL;
3933
3934 /*
3935 * Change the kobject and the default attributes and groups of the
3936 * ktype associated with it to @kuid/@kgid.
3937 */
3938 error = sysfs_change_owner(kobj, kuid, kgid);
3939 if (error)
3940 goto out;
3941
3942 /*
3943 * Change the uevent file for @dev to the new owner. The uevent file
3944 * was created in a separate step when @dev got added and we mirror
3945 * that step here.
3946 */
3947 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
3948 kgid);
3949 if (error)
3950 goto out;
3951
3952 /*
3953 * Change the device groups, the device groups associated with the
3954 * device class, and the groups associated with the device type of @dev
3955 * to @kuid/@kgid.
3956 */
3957 error = device_attrs_change_owner(dev, kuid, kgid);
3958 if (error)
3959 goto out;
3960
3961 error = dpm_sysfs_change_owner(dev, kuid, kgid);
3962 if (error)
3963 goto out;
3964
3965#ifdef CONFIG_BLOCK
3966 if (sysfs_deprecated && dev->class == &block_class)
3967 goto out;
3968#endif
3969
3970 /*
3971 * Change the owner of the symlink located in the class directory of
3972 * the device class associated with @dev which points to the actual
3973 * directory entry for @dev to @kuid/@kgid. This ensures that the
3974 * symlink shows the same permissions as its target.
3975 */
3976 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
3977 dev_name(dev), kuid, kgid);
3978 if (error)
3979 goto out;
3980
3981out:
3982 put_device(dev);
3983 return error;
3984}
3985EXPORT_SYMBOL_GPL(device_change_owner);
3986
3987/**
3988 * device_shutdown - call ->shutdown() on each device to shutdown.
3989 */
3990void device_shutdown(void)
3991{
3992 struct device *dev, *parent;
3993
3994 wait_for_device_probe();
3995 device_block_probing();
3996
3997 cpufreq_suspend();
3998
3999 spin_lock(&devices_kset->list_lock);
4000 /*
4001 * Walk the devices list backward, shutting down each in turn.
4002 * Beware that device unplug events may also start pulling
4003 * devices offline, even as the system is shutting down.
4004 */
4005 while (!list_empty(&devices_kset->list)) {
4006 dev = list_entry(devices_kset->list.prev, struct device,
4007 kobj.entry);
4008
4009 /*
4010 * hold reference count of device's parent to
4011 * prevent it from being freed because parent's
4012 * lock is to be held
4013 */
4014 parent = get_device(dev->parent);
4015 get_device(dev);
4016 /*
4017 * Make sure the device is off the kset list, in the
4018 * event that dev->*->shutdown() doesn't remove it.
4019 */
4020 list_del_init(&dev->kobj.entry);
4021 spin_unlock(&devices_kset->list_lock);
4022
4023 /* hold lock to avoid race with probe/release */
4024 if (parent)
4025 device_lock(parent);
4026 device_lock(dev);
4027
4028 /* Don't allow any more runtime suspends */
4029 pm_runtime_get_noresume(dev);
4030 pm_runtime_barrier(dev);
4031
4032 if (dev->class && dev->class->shutdown_pre) {
4033 if (initcall_debug)
4034 dev_info(dev, "shutdown_pre\n");
4035 dev->class->shutdown_pre(dev);
4036 }
4037 if (dev->bus && dev->bus->shutdown) {
4038 if (initcall_debug)
4039 dev_info(dev, "shutdown\n");
4040 dev->bus->shutdown(dev);
4041 } else if (dev->driver && dev->driver->shutdown) {
4042 if (initcall_debug)
4043 dev_info(dev, "shutdown\n");
4044 dev->driver->shutdown(dev);
4045 }
4046
4047 device_unlock(dev);
4048 if (parent)
4049 device_unlock(parent);
4050
4051 put_device(dev);
4052 put_device(parent);
4053
4054 spin_lock(&devices_kset->list_lock);
4055 }
4056 spin_unlock(&devices_kset->list_lock);
4057}
4058
4059/*
4060 * Device logging functions
4061 */
4062
4063#ifdef CONFIG_PRINTK
4064static int
4065create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
4066{
4067 const char *subsys;
4068 size_t pos = 0;
4069
4070 if (dev->class)
4071 subsys = dev->class->name;
4072 else if (dev->bus)
4073 subsys = dev->bus->name;
4074 else
4075 return 0;
4076
4077 pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
4078 if (pos >= hdrlen)
4079 goto overflow;
4080
4081 /*
4082 * Add device identifier DEVICE=:
4083 * b12:8 block dev_t
4084 * c127:3 char dev_t
4085 * n8 netdev ifindex
4086 * +sound:card0 subsystem:devname
4087 */
4088 if (MAJOR(dev->devt)) {
4089 char c;
4090
4091 if (strcmp(subsys, "block") == 0)
4092 c = 'b';
4093 else
4094 c = 'c';
4095 pos++;
4096 pos += snprintf(hdr + pos, hdrlen - pos,
4097 "DEVICE=%c%u:%u",
4098 c, MAJOR(dev->devt), MINOR(dev->devt));
4099 } else if (strcmp(subsys, "net") == 0) {
4100 struct net_device *net = to_net_dev(dev);
4101
4102 pos++;
4103 pos += snprintf(hdr + pos, hdrlen - pos,
4104 "DEVICE=n%u", net->ifindex);
4105 } else {
4106 pos++;
4107 pos += snprintf(hdr + pos, hdrlen - pos,
4108 "DEVICE=+%s:%s", subsys, dev_name(dev));
4109 }
4110
4111 if (pos >= hdrlen)
4112 goto overflow;
4113
4114 return pos;
4115
4116overflow:
4117 dev_WARN(dev, "device/subsystem name too long");
4118 return 0;
4119}
4120
4121int dev_vprintk_emit(int level, const struct device *dev,
4122 const char *fmt, va_list args)
4123{
4124 char hdr[128];
4125 size_t hdrlen;
4126
4127 hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
4128
4129 return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
4130}
4131EXPORT_SYMBOL(dev_vprintk_emit);
4132
4133int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4134{
4135 va_list args;
4136 int r;
4137
4138 va_start(args, fmt);
4139
4140 r = dev_vprintk_emit(level, dev, fmt, args);
4141
4142 va_end(args);
4143
4144 return r;
4145}
4146EXPORT_SYMBOL(dev_printk_emit);
4147
4148static void __dev_printk(const char *level, const struct device *dev,
4149 struct va_format *vaf)
4150{
4151 if (dev)
4152 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4153 dev_driver_string(dev), dev_name(dev), vaf);
4154 else
4155 printk("%s(NULL device *): %pV", level, vaf);
4156}
4157
4158void dev_printk(const char *level, const struct device *dev,
4159 const char *fmt, ...)
4160{
4161 struct va_format vaf;
4162 va_list args;
4163
4164 va_start(args, fmt);
4165
4166 vaf.fmt = fmt;
4167 vaf.va = &args;
4168
4169 __dev_printk(level, dev, &vaf);
4170
4171 va_end(args);
4172}
4173EXPORT_SYMBOL(dev_printk);
4174
4175#define define_dev_printk_level(func, kern_level) \
4176void func(const struct device *dev, const char *fmt, ...) \
4177{ \
4178 struct va_format vaf; \
4179 va_list args; \
4180 \
4181 va_start(args, fmt); \
4182 \
4183 vaf.fmt = fmt; \
4184 vaf.va = &args; \
4185 \
4186 __dev_printk(kern_level, dev, &vaf); \
4187 \
4188 va_end(args); \
4189} \
4190EXPORT_SYMBOL(func);
4191
4192define_dev_printk_level(_dev_emerg, KERN_EMERG);
4193define_dev_printk_level(_dev_alert, KERN_ALERT);
4194define_dev_printk_level(_dev_crit, KERN_CRIT);
4195define_dev_printk_level(_dev_err, KERN_ERR);
4196define_dev_printk_level(_dev_warn, KERN_WARNING);
4197define_dev_printk_level(_dev_notice, KERN_NOTICE);
4198define_dev_printk_level(_dev_info, KERN_INFO);
4199
4200#endif
4201
4202/**
4203 * dev_err_probe - probe error check and log helper
4204 * @dev: the pointer to the struct device
4205 * @err: error value to test
4206 * @fmt: printf-style format string
4207 * @...: arguments as specified in the format string
4208 *
4209 * This helper implements common pattern present in probe functions for error
4210 * checking: print debug or error message depending if the error value is
4211 * -EPROBE_DEFER and propagate error upwards.
4212 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4213 * checked later by reading devices_deferred debugfs attribute.
4214 * It replaces code sequence:
4215 * if (err != -EPROBE_DEFER)
4216 * dev_err(dev, ...);
4217 * else
4218 * dev_dbg(dev, ...);
4219 * return err;
4220 * with
4221 * return dev_err_probe(dev, err, ...);
4222 *
4223 * Returns @err.
4224 *
4225 */
4226int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4227{
4228 struct va_format vaf;
4229 va_list args;
4230
4231 va_start(args, fmt);
4232 vaf.fmt = fmt;
4233 vaf.va = &args;
4234
4235 if (err != -EPROBE_DEFER) {
4236 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4237 } else {
4238 device_set_deferred_probe_reason(dev, &vaf);
4239 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4240 }
4241
4242 va_end(args);
4243
4244 return err;
4245}
4246EXPORT_SYMBOL_GPL(dev_err_probe);
4247
4248static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4249{
4250 return fwnode && !IS_ERR(fwnode->secondary);
4251}
4252
4253/**
4254 * set_primary_fwnode - Change the primary firmware node of a given device.
4255 * @dev: Device to handle.
4256 * @fwnode: New primary firmware node of the device.
4257 *
4258 * Set the device's firmware node pointer to @fwnode, but if a secondary
4259 * firmware node of the device is present, preserve it.
4260 */
4261void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4262{
4263 struct fwnode_handle *fn = dev->fwnode;
4264
4265 if (fwnode) {
4266 if (fwnode_is_primary(fn))
4267 fn = fn->secondary;
4268
4269 if (fn) {
4270 WARN_ON(fwnode->secondary);
4271 fwnode->secondary = fn;
4272 }
4273 dev->fwnode = fwnode;
4274 } else {
4275 if (fwnode_is_primary(fn)) {
4276 dev->fwnode = fn->secondary;
4277 fn->secondary = NULL;
4278 } else {
4279 dev->fwnode = NULL;
4280 }
4281 }
4282}
4283EXPORT_SYMBOL_GPL(set_primary_fwnode);
4284
4285/**
4286 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4287 * @dev: Device to handle.
4288 * @fwnode: New secondary firmware node of the device.
4289 *
4290 * If a primary firmware node of the device is present, set its secondary
4291 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4292 * @fwnode.
4293 */
4294void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4295{
4296 if (fwnode)
4297 fwnode->secondary = ERR_PTR(-ENODEV);
4298
4299 if (fwnode_is_primary(dev->fwnode))
4300 dev->fwnode->secondary = fwnode;
4301 else
4302 dev->fwnode = fwnode;
4303}
4304EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4305
4306/**
4307 * device_set_of_node_from_dev - reuse device-tree node of another device
4308 * @dev: device whose device-tree node is being set
4309 * @dev2: device whose device-tree node is being reused
4310 *
4311 * Takes another reference to the new device-tree node after first dropping
4312 * any reference held to the old node.
4313 */
4314void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4315{
4316 of_node_put(dev->of_node);
4317 dev->of_node = of_node_get(dev2->of_node);
4318 dev->of_node_reused = true;
4319}
4320EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4321
4322int device_match_name(struct device *dev, const void *name)
4323{
4324 return sysfs_streq(dev_name(dev), name);
4325}
4326EXPORT_SYMBOL_GPL(device_match_name);
4327
4328int device_match_of_node(struct device *dev, const void *np)
4329{
4330 return dev->of_node == np;
4331}
4332EXPORT_SYMBOL_GPL(device_match_of_node);
4333
4334int device_match_fwnode(struct device *dev, const void *fwnode)
4335{
4336 return dev_fwnode(dev) == fwnode;
4337}
4338EXPORT_SYMBOL_GPL(device_match_fwnode);
4339
4340int device_match_devt(struct device *dev, const void *pdevt)
4341{
4342 return dev->devt == *(dev_t *)pdevt;
4343}
4344EXPORT_SYMBOL_GPL(device_match_devt);
4345
4346int device_match_acpi_dev(struct device *dev, const void *adev)
4347{
4348 return ACPI_COMPANION(dev) == adev;
4349}
4350EXPORT_SYMBOL(device_match_acpi_dev);
4351
4352int device_match_any(struct device *dev, const void *unused)
4353{
4354 return 1;
4355}
4356EXPORT_SYMBOL_GPL(device_match_any);
1/*
2 * drivers/base/core.c - core driver model code (device registration, etc)
3 *
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (c) 2006 Novell, Inc.
8 *
9 * This file is released under the GPLv2
10 *
11 */
12
13#include <linux/device.h>
14#include <linux/err.h>
15#include <linux/init.h>
16#include <linux/module.h>
17#include <linux/slab.h>
18#include <linux/string.h>
19#include <linux/kdev_t.h>
20#include <linux/notifier.h>
21#include <linux/of.h>
22#include <linux/of_device.h>
23#include <linux/genhd.h>
24#include <linux/kallsyms.h>
25#include <linux/mutex.h>
26#include <linux/pm_runtime.h>
27#include <linux/netdevice.h>
28#include <linux/sysfs.h>
29
30#include "base.h"
31#include "power/power.h"
32
33#ifdef CONFIG_SYSFS_DEPRECATED
34#ifdef CONFIG_SYSFS_DEPRECATED_V2
35long sysfs_deprecated = 1;
36#else
37long sysfs_deprecated = 0;
38#endif
39static int __init sysfs_deprecated_setup(char *arg)
40{
41 return kstrtol(arg, 10, &sysfs_deprecated);
42}
43early_param("sysfs.deprecated", sysfs_deprecated_setup);
44#endif
45
46int (*platform_notify)(struct device *dev) = NULL;
47int (*platform_notify_remove)(struct device *dev) = NULL;
48static struct kobject *dev_kobj;
49struct kobject *sysfs_dev_char_kobj;
50struct kobject *sysfs_dev_block_kobj;
51
52static DEFINE_MUTEX(device_hotplug_lock);
53
54void lock_device_hotplug(void)
55{
56 mutex_lock(&device_hotplug_lock);
57}
58
59void unlock_device_hotplug(void)
60{
61 mutex_unlock(&device_hotplug_lock);
62}
63
64int lock_device_hotplug_sysfs(void)
65{
66 if (mutex_trylock(&device_hotplug_lock))
67 return 0;
68
69 /* Avoid busy looping (5 ms of sleep should do). */
70 msleep(5);
71 return restart_syscall();
72}
73
74#ifdef CONFIG_BLOCK
75static inline int device_is_not_partition(struct device *dev)
76{
77 return !(dev->type == &part_type);
78}
79#else
80static inline int device_is_not_partition(struct device *dev)
81{
82 return 1;
83}
84#endif
85
86/**
87 * dev_driver_string - Return a device's driver name, if at all possible
88 * @dev: struct device to get the name of
89 *
90 * Will return the device's driver's name if it is bound to a device. If
91 * the device is not bound to a driver, it will return the name of the bus
92 * it is attached to. If it is not attached to a bus either, an empty
93 * string will be returned.
94 */
95const char *dev_driver_string(const struct device *dev)
96{
97 struct device_driver *drv;
98
99 /* dev->driver can change to NULL underneath us because of unbinding,
100 * so be careful about accessing it. dev->bus and dev->class should
101 * never change once they are set, so they don't need special care.
102 */
103 drv = ACCESS_ONCE(dev->driver);
104 return drv ? drv->name :
105 (dev->bus ? dev->bus->name :
106 (dev->class ? dev->class->name : ""));
107}
108EXPORT_SYMBOL(dev_driver_string);
109
110#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
111
112static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
113 char *buf)
114{
115 struct device_attribute *dev_attr = to_dev_attr(attr);
116 struct device *dev = kobj_to_dev(kobj);
117 ssize_t ret = -EIO;
118
119 if (dev_attr->show)
120 ret = dev_attr->show(dev, dev_attr, buf);
121 if (ret >= (ssize_t)PAGE_SIZE) {
122 print_symbol("dev_attr_show: %s returned bad count\n",
123 (unsigned long)dev_attr->show);
124 }
125 return ret;
126}
127
128static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
129 const char *buf, size_t count)
130{
131 struct device_attribute *dev_attr = to_dev_attr(attr);
132 struct device *dev = kobj_to_dev(kobj);
133 ssize_t ret = -EIO;
134
135 if (dev_attr->store)
136 ret = dev_attr->store(dev, dev_attr, buf, count);
137 return ret;
138}
139
140static const struct sysfs_ops dev_sysfs_ops = {
141 .show = dev_attr_show,
142 .store = dev_attr_store,
143};
144
145#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
146
147ssize_t device_store_ulong(struct device *dev,
148 struct device_attribute *attr,
149 const char *buf, size_t size)
150{
151 struct dev_ext_attribute *ea = to_ext_attr(attr);
152 char *end;
153 unsigned long new = simple_strtoul(buf, &end, 0);
154 if (end == buf)
155 return -EINVAL;
156 *(unsigned long *)(ea->var) = new;
157 /* Always return full write size even if we didn't consume all */
158 return size;
159}
160EXPORT_SYMBOL_GPL(device_store_ulong);
161
162ssize_t device_show_ulong(struct device *dev,
163 struct device_attribute *attr,
164 char *buf)
165{
166 struct dev_ext_attribute *ea = to_ext_attr(attr);
167 return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
168}
169EXPORT_SYMBOL_GPL(device_show_ulong);
170
171ssize_t device_store_int(struct device *dev,
172 struct device_attribute *attr,
173 const char *buf, size_t size)
174{
175 struct dev_ext_attribute *ea = to_ext_attr(attr);
176 char *end;
177 long new = simple_strtol(buf, &end, 0);
178 if (end == buf || new > INT_MAX || new < INT_MIN)
179 return -EINVAL;
180 *(int *)(ea->var) = new;
181 /* Always return full write size even if we didn't consume all */
182 return size;
183}
184EXPORT_SYMBOL_GPL(device_store_int);
185
186ssize_t device_show_int(struct device *dev,
187 struct device_attribute *attr,
188 char *buf)
189{
190 struct dev_ext_attribute *ea = to_ext_attr(attr);
191
192 return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
193}
194EXPORT_SYMBOL_GPL(device_show_int);
195
196ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
197 const char *buf, size_t size)
198{
199 struct dev_ext_attribute *ea = to_ext_attr(attr);
200
201 if (strtobool(buf, ea->var) < 0)
202 return -EINVAL;
203
204 return size;
205}
206EXPORT_SYMBOL_GPL(device_store_bool);
207
208ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
209 char *buf)
210{
211 struct dev_ext_attribute *ea = to_ext_attr(attr);
212
213 return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
214}
215EXPORT_SYMBOL_GPL(device_show_bool);
216
217/**
218 * device_release - free device structure.
219 * @kobj: device's kobject.
220 *
221 * This is called once the reference count for the object
222 * reaches 0. We forward the call to the device's release
223 * method, which should handle actually freeing the structure.
224 */
225static void device_release(struct kobject *kobj)
226{
227 struct device *dev = kobj_to_dev(kobj);
228 struct device_private *p = dev->p;
229
230 /*
231 * Some platform devices are driven without driver attached
232 * and managed resources may have been acquired. Make sure
233 * all resources are released.
234 *
235 * Drivers still can add resources into device after device
236 * is deleted but alive, so release devres here to avoid
237 * possible memory leak.
238 */
239 devres_release_all(dev);
240
241 if (dev->release)
242 dev->release(dev);
243 else if (dev->type && dev->type->release)
244 dev->type->release(dev);
245 else if (dev->class && dev->class->dev_release)
246 dev->class->dev_release(dev);
247 else
248 WARN(1, KERN_ERR "Device '%s' does not have a release() "
249 "function, it is broken and must be fixed.\n",
250 dev_name(dev));
251 kfree(p);
252}
253
254static const void *device_namespace(struct kobject *kobj)
255{
256 struct device *dev = kobj_to_dev(kobj);
257 const void *ns = NULL;
258
259 if (dev->class && dev->class->ns_type)
260 ns = dev->class->namespace(dev);
261
262 return ns;
263}
264
265static struct kobj_type device_ktype = {
266 .release = device_release,
267 .sysfs_ops = &dev_sysfs_ops,
268 .namespace = device_namespace,
269};
270
271
272static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
273{
274 struct kobj_type *ktype = get_ktype(kobj);
275
276 if (ktype == &device_ktype) {
277 struct device *dev = kobj_to_dev(kobj);
278 if (dev->bus)
279 return 1;
280 if (dev->class)
281 return 1;
282 }
283 return 0;
284}
285
286static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
287{
288 struct device *dev = kobj_to_dev(kobj);
289
290 if (dev->bus)
291 return dev->bus->name;
292 if (dev->class)
293 return dev->class->name;
294 return NULL;
295}
296
297static int dev_uevent(struct kset *kset, struct kobject *kobj,
298 struct kobj_uevent_env *env)
299{
300 struct device *dev = kobj_to_dev(kobj);
301 int retval = 0;
302
303 /* add device node properties if present */
304 if (MAJOR(dev->devt)) {
305 const char *tmp;
306 const char *name;
307 umode_t mode = 0;
308 kuid_t uid = GLOBAL_ROOT_UID;
309 kgid_t gid = GLOBAL_ROOT_GID;
310
311 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
312 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
313 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
314 if (name) {
315 add_uevent_var(env, "DEVNAME=%s", name);
316 if (mode)
317 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
318 if (!uid_eq(uid, GLOBAL_ROOT_UID))
319 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
320 if (!gid_eq(gid, GLOBAL_ROOT_GID))
321 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
322 kfree(tmp);
323 }
324 }
325
326 if (dev->type && dev->type->name)
327 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
328
329 if (dev->driver)
330 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
331
332 /* Add common DT information about the device */
333 of_device_uevent(dev, env);
334
335 /* have the bus specific function add its stuff */
336 if (dev->bus && dev->bus->uevent) {
337 retval = dev->bus->uevent(dev, env);
338 if (retval)
339 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
340 dev_name(dev), __func__, retval);
341 }
342
343 /* have the class specific function add its stuff */
344 if (dev->class && dev->class->dev_uevent) {
345 retval = dev->class->dev_uevent(dev, env);
346 if (retval)
347 pr_debug("device: '%s': %s: class uevent() "
348 "returned %d\n", dev_name(dev),
349 __func__, retval);
350 }
351
352 /* have the device type specific function add its stuff */
353 if (dev->type && dev->type->uevent) {
354 retval = dev->type->uevent(dev, env);
355 if (retval)
356 pr_debug("device: '%s': %s: dev_type uevent() "
357 "returned %d\n", dev_name(dev),
358 __func__, retval);
359 }
360
361 return retval;
362}
363
364static const struct kset_uevent_ops device_uevent_ops = {
365 .filter = dev_uevent_filter,
366 .name = dev_uevent_name,
367 .uevent = dev_uevent,
368};
369
370static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
371 char *buf)
372{
373 struct kobject *top_kobj;
374 struct kset *kset;
375 struct kobj_uevent_env *env = NULL;
376 int i;
377 size_t count = 0;
378 int retval;
379
380 /* search the kset, the device belongs to */
381 top_kobj = &dev->kobj;
382 while (!top_kobj->kset && top_kobj->parent)
383 top_kobj = top_kobj->parent;
384 if (!top_kobj->kset)
385 goto out;
386
387 kset = top_kobj->kset;
388 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
389 goto out;
390
391 /* respect filter */
392 if (kset->uevent_ops && kset->uevent_ops->filter)
393 if (!kset->uevent_ops->filter(kset, &dev->kobj))
394 goto out;
395
396 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
397 if (!env)
398 return -ENOMEM;
399
400 /* let the kset specific function add its keys */
401 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
402 if (retval)
403 goto out;
404
405 /* copy keys to file */
406 for (i = 0; i < env->envp_idx; i++)
407 count += sprintf(&buf[count], "%s\n", env->envp[i]);
408out:
409 kfree(env);
410 return count;
411}
412
413static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
414 const char *buf, size_t count)
415{
416 enum kobject_action action;
417
418 if (kobject_action_type(buf, count, &action) == 0)
419 kobject_uevent(&dev->kobj, action);
420 else
421 dev_err(dev, "uevent: unknown action-string\n");
422 return count;
423}
424static DEVICE_ATTR_RW(uevent);
425
426static ssize_t online_show(struct device *dev, struct device_attribute *attr,
427 char *buf)
428{
429 bool val;
430
431 device_lock(dev);
432 val = !dev->offline;
433 device_unlock(dev);
434 return sprintf(buf, "%u\n", val);
435}
436
437static ssize_t online_store(struct device *dev, struct device_attribute *attr,
438 const char *buf, size_t count)
439{
440 bool val;
441 int ret;
442
443 ret = strtobool(buf, &val);
444 if (ret < 0)
445 return ret;
446
447 ret = lock_device_hotplug_sysfs();
448 if (ret)
449 return ret;
450
451 ret = val ? device_online(dev) : device_offline(dev);
452 unlock_device_hotplug();
453 return ret < 0 ? ret : count;
454}
455static DEVICE_ATTR_RW(online);
456
457int device_add_groups(struct device *dev, const struct attribute_group **groups)
458{
459 return sysfs_create_groups(&dev->kobj, groups);
460}
461
462void device_remove_groups(struct device *dev,
463 const struct attribute_group **groups)
464{
465 sysfs_remove_groups(&dev->kobj, groups);
466}
467
468static int device_add_attrs(struct device *dev)
469{
470 struct class *class = dev->class;
471 const struct device_type *type = dev->type;
472 int error;
473
474 if (class) {
475 error = device_add_groups(dev, class->dev_groups);
476 if (error)
477 return error;
478 }
479
480 if (type) {
481 error = device_add_groups(dev, type->groups);
482 if (error)
483 goto err_remove_class_groups;
484 }
485
486 error = device_add_groups(dev, dev->groups);
487 if (error)
488 goto err_remove_type_groups;
489
490 if (device_supports_offline(dev) && !dev->offline_disabled) {
491 error = device_create_file(dev, &dev_attr_online);
492 if (error)
493 goto err_remove_dev_groups;
494 }
495
496 return 0;
497
498 err_remove_dev_groups:
499 device_remove_groups(dev, dev->groups);
500 err_remove_type_groups:
501 if (type)
502 device_remove_groups(dev, type->groups);
503 err_remove_class_groups:
504 if (class)
505 device_remove_groups(dev, class->dev_groups);
506
507 return error;
508}
509
510static void device_remove_attrs(struct device *dev)
511{
512 struct class *class = dev->class;
513 const struct device_type *type = dev->type;
514
515 device_remove_file(dev, &dev_attr_online);
516 device_remove_groups(dev, dev->groups);
517
518 if (type)
519 device_remove_groups(dev, type->groups);
520
521 if (class)
522 device_remove_groups(dev, class->dev_groups);
523}
524
525static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
526 char *buf)
527{
528 return print_dev_t(buf, dev->devt);
529}
530static DEVICE_ATTR_RO(dev);
531
532/* /sys/devices/ */
533struct kset *devices_kset;
534
535/**
536 * device_create_file - create sysfs attribute file for device.
537 * @dev: device.
538 * @attr: device attribute descriptor.
539 */
540int device_create_file(struct device *dev,
541 const struct device_attribute *attr)
542{
543 int error = 0;
544
545 if (dev) {
546 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
547 "Attribute %s: write permission without 'store'\n",
548 attr->attr.name);
549 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
550 "Attribute %s: read permission without 'show'\n",
551 attr->attr.name);
552 error = sysfs_create_file(&dev->kobj, &attr->attr);
553 }
554
555 return error;
556}
557EXPORT_SYMBOL_GPL(device_create_file);
558
559/**
560 * device_remove_file - remove sysfs attribute file.
561 * @dev: device.
562 * @attr: device attribute descriptor.
563 */
564void device_remove_file(struct device *dev,
565 const struct device_attribute *attr)
566{
567 if (dev)
568 sysfs_remove_file(&dev->kobj, &attr->attr);
569}
570EXPORT_SYMBOL_GPL(device_remove_file);
571
572/**
573 * device_remove_file_self - remove sysfs attribute file from its own method.
574 * @dev: device.
575 * @attr: device attribute descriptor.
576 *
577 * See kernfs_remove_self() for details.
578 */
579bool device_remove_file_self(struct device *dev,
580 const struct device_attribute *attr)
581{
582 if (dev)
583 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
584 else
585 return false;
586}
587EXPORT_SYMBOL_GPL(device_remove_file_self);
588
589/**
590 * device_create_bin_file - create sysfs binary attribute file for device.
591 * @dev: device.
592 * @attr: device binary attribute descriptor.
593 */
594int device_create_bin_file(struct device *dev,
595 const struct bin_attribute *attr)
596{
597 int error = -EINVAL;
598 if (dev)
599 error = sysfs_create_bin_file(&dev->kobj, attr);
600 return error;
601}
602EXPORT_SYMBOL_GPL(device_create_bin_file);
603
604/**
605 * device_remove_bin_file - remove sysfs binary attribute file
606 * @dev: device.
607 * @attr: device binary attribute descriptor.
608 */
609void device_remove_bin_file(struct device *dev,
610 const struct bin_attribute *attr)
611{
612 if (dev)
613 sysfs_remove_bin_file(&dev->kobj, attr);
614}
615EXPORT_SYMBOL_GPL(device_remove_bin_file);
616
617static void klist_children_get(struct klist_node *n)
618{
619 struct device_private *p = to_device_private_parent(n);
620 struct device *dev = p->device;
621
622 get_device(dev);
623}
624
625static void klist_children_put(struct klist_node *n)
626{
627 struct device_private *p = to_device_private_parent(n);
628 struct device *dev = p->device;
629
630 put_device(dev);
631}
632
633/**
634 * device_initialize - init device structure.
635 * @dev: device.
636 *
637 * This prepares the device for use by other layers by initializing
638 * its fields.
639 * It is the first half of device_register(), if called by
640 * that function, though it can also be called separately, so one
641 * may use @dev's fields. In particular, get_device()/put_device()
642 * may be used for reference counting of @dev after calling this
643 * function.
644 *
645 * All fields in @dev must be initialized by the caller to 0, except
646 * for those explicitly set to some other value. The simplest
647 * approach is to use kzalloc() to allocate the structure containing
648 * @dev.
649 *
650 * NOTE: Use put_device() to give up your reference instead of freeing
651 * @dev directly once you have called this function.
652 */
653void device_initialize(struct device *dev)
654{
655 dev->kobj.kset = devices_kset;
656 kobject_init(&dev->kobj, &device_ktype);
657 INIT_LIST_HEAD(&dev->dma_pools);
658 mutex_init(&dev->mutex);
659 lockdep_set_novalidate_class(&dev->mutex);
660 spin_lock_init(&dev->devres_lock);
661 INIT_LIST_HEAD(&dev->devres_head);
662 device_pm_init(dev);
663 set_dev_node(dev, -1);
664}
665EXPORT_SYMBOL_GPL(device_initialize);
666
667struct kobject *virtual_device_parent(struct device *dev)
668{
669 static struct kobject *virtual_dir = NULL;
670
671 if (!virtual_dir)
672 virtual_dir = kobject_create_and_add("virtual",
673 &devices_kset->kobj);
674
675 return virtual_dir;
676}
677
678struct class_dir {
679 struct kobject kobj;
680 struct class *class;
681};
682
683#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
684
685static void class_dir_release(struct kobject *kobj)
686{
687 struct class_dir *dir = to_class_dir(kobj);
688 kfree(dir);
689}
690
691static const
692struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
693{
694 struct class_dir *dir = to_class_dir(kobj);
695 return dir->class->ns_type;
696}
697
698static struct kobj_type class_dir_ktype = {
699 .release = class_dir_release,
700 .sysfs_ops = &kobj_sysfs_ops,
701 .child_ns_type = class_dir_child_ns_type
702};
703
704static struct kobject *
705class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
706{
707 struct class_dir *dir;
708 int retval;
709
710 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
711 if (!dir)
712 return NULL;
713
714 dir->class = class;
715 kobject_init(&dir->kobj, &class_dir_ktype);
716
717 dir->kobj.kset = &class->p->glue_dirs;
718
719 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
720 if (retval < 0) {
721 kobject_put(&dir->kobj);
722 return NULL;
723 }
724 return &dir->kobj;
725}
726
727
728static struct kobject *get_device_parent(struct device *dev,
729 struct device *parent)
730{
731 if (dev->class) {
732 static DEFINE_MUTEX(gdp_mutex);
733 struct kobject *kobj = NULL;
734 struct kobject *parent_kobj;
735 struct kobject *k;
736
737#ifdef CONFIG_BLOCK
738 /* block disks show up in /sys/block */
739 if (sysfs_deprecated && dev->class == &block_class) {
740 if (parent && parent->class == &block_class)
741 return &parent->kobj;
742 return &block_class.p->subsys.kobj;
743 }
744#endif
745
746 /*
747 * If we have no parent, we live in "virtual".
748 * Class-devices with a non class-device as parent, live
749 * in a "glue" directory to prevent namespace collisions.
750 */
751 if (parent == NULL)
752 parent_kobj = virtual_device_parent(dev);
753 else if (parent->class && !dev->class->ns_type)
754 return &parent->kobj;
755 else
756 parent_kobj = &parent->kobj;
757
758 mutex_lock(&gdp_mutex);
759
760 /* find our class-directory at the parent and reference it */
761 spin_lock(&dev->class->p->glue_dirs.list_lock);
762 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
763 if (k->parent == parent_kobj) {
764 kobj = kobject_get(k);
765 break;
766 }
767 spin_unlock(&dev->class->p->glue_dirs.list_lock);
768 if (kobj) {
769 mutex_unlock(&gdp_mutex);
770 return kobj;
771 }
772
773 /* or create a new class-directory at the parent device */
774 k = class_dir_create_and_add(dev->class, parent_kobj);
775 /* do not emit an uevent for this simple "glue" directory */
776 mutex_unlock(&gdp_mutex);
777 return k;
778 }
779
780 /* subsystems can specify a default root directory for their devices */
781 if (!parent && dev->bus && dev->bus->dev_root)
782 return &dev->bus->dev_root->kobj;
783
784 if (parent)
785 return &parent->kobj;
786 return NULL;
787}
788
789static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
790{
791 /* see if we live in a "glue" directory */
792 if (!glue_dir || !dev->class ||
793 glue_dir->kset != &dev->class->p->glue_dirs)
794 return;
795
796 kobject_put(glue_dir);
797}
798
799static void cleanup_device_parent(struct device *dev)
800{
801 cleanup_glue_dir(dev, dev->kobj.parent);
802}
803
804static int device_add_class_symlinks(struct device *dev)
805{
806 int error;
807
808 if (!dev->class)
809 return 0;
810
811 error = sysfs_create_link(&dev->kobj,
812 &dev->class->p->subsys.kobj,
813 "subsystem");
814 if (error)
815 goto out;
816
817 if (dev->parent && device_is_not_partition(dev)) {
818 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
819 "device");
820 if (error)
821 goto out_subsys;
822 }
823
824#ifdef CONFIG_BLOCK
825 /* /sys/block has directories and does not need symlinks */
826 if (sysfs_deprecated && dev->class == &block_class)
827 return 0;
828#endif
829
830 /* link in the class directory pointing to the device */
831 error = sysfs_create_link(&dev->class->p->subsys.kobj,
832 &dev->kobj, dev_name(dev));
833 if (error)
834 goto out_device;
835
836 return 0;
837
838out_device:
839 sysfs_remove_link(&dev->kobj, "device");
840
841out_subsys:
842 sysfs_remove_link(&dev->kobj, "subsystem");
843out:
844 return error;
845}
846
847static void device_remove_class_symlinks(struct device *dev)
848{
849 if (!dev->class)
850 return;
851
852 if (dev->parent && device_is_not_partition(dev))
853 sysfs_remove_link(&dev->kobj, "device");
854 sysfs_remove_link(&dev->kobj, "subsystem");
855#ifdef CONFIG_BLOCK
856 if (sysfs_deprecated && dev->class == &block_class)
857 return;
858#endif
859 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
860}
861
862/**
863 * dev_set_name - set a device name
864 * @dev: device
865 * @fmt: format string for the device's name
866 */
867int dev_set_name(struct device *dev, const char *fmt, ...)
868{
869 va_list vargs;
870 int err;
871
872 va_start(vargs, fmt);
873 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
874 va_end(vargs);
875 return err;
876}
877EXPORT_SYMBOL_GPL(dev_set_name);
878
879/**
880 * device_to_dev_kobj - select a /sys/dev/ directory for the device
881 * @dev: device
882 *
883 * By default we select char/ for new entries. Setting class->dev_obj
884 * to NULL prevents an entry from being created. class->dev_kobj must
885 * be set (or cleared) before any devices are registered to the class
886 * otherwise device_create_sys_dev_entry() and
887 * device_remove_sys_dev_entry() will disagree about the presence of
888 * the link.
889 */
890static struct kobject *device_to_dev_kobj(struct device *dev)
891{
892 struct kobject *kobj;
893
894 if (dev->class)
895 kobj = dev->class->dev_kobj;
896 else
897 kobj = sysfs_dev_char_kobj;
898
899 return kobj;
900}
901
902static int device_create_sys_dev_entry(struct device *dev)
903{
904 struct kobject *kobj = device_to_dev_kobj(dev);
905 int error = 0;
906 char devt_str[15];
907
908 if (kobj) {
909 format_dev_t(devt_str, dev->devt);
910 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
911 }
912
913 return error;
914}
915
916static void device_remove_sys_dev_entry(struct device *dev)
917{
918 struct kobject *kobj = device_to_dev_kobj(dev);
919 char devt_str[15];
920
921 if (kobj) {
922 format_dev_t(devt_str, dev->devt);
923 sysfs_remove_link(kobj, devt_str);
924 }
925}
926
927int device_private_init(struct device *dev)
928{
929 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
930 if (!dev->p)
931 return -ENOMEM;
932 dev->p->device = dev;
933 klist_init(&dev->p->klist_children, klist_children_get,
934 klist_children_put);
935 INIT_LIST_HEAD(&dev->p->deferred_probe);
936 return 0;
937}
938
939/**
940 * device_add - add device to device hierarchy.
941 * @dev: device.
942 *
943 * This is part 2 of device_register(), though may be called
944 * separately _iff_ device_initialize() has been called separately.
945 *
946 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
947 * to the global and sibling lists for the device, then
948 * adds it to the other relevant subsystems of the driver model.
949 *
950 * Do not call this routine or device_register() more than once for
951 * any device structure. The driver model core is not designed to work
952 * with devices that get unregistered and then spring back to life.
953 * (Among other things, it's very hard to guarantee that all references
954 * to the previous incarnation of @dev have been dropped.) Allocate
955 * and register a fresh new struct device instead.
956 *
957 * NOTE: _Never_ directly free @dev after calling this function, even
958 * if it returned an error! Always use put_device() to give up your
959 * reference instead.
960 */
961int device_add(struct device *dev)
962{
963 struct device *parent = NULL;
964 struct kobject *kobj;
965 struct class_interface *class_intf;
966 int error = -EINVAL;
967
968 dev = get_device(dev);
969 if (!dev)
970 goto done;
971
972 if (!dev->p) {
973 error = device_private_init(dev);
974 if (error)
975 goto done;
976 }
977
978 /*
979 * for statically allocated devices, which should all be converted
980 * some day, we need to initialize the name. We prevent reading back
981 * the name, and force the use of dev_name()
982 */
983 if (dev->init_name) {
984 dev_set_name(dev, "%s", dev->init_name);
985 dev->init_name = NULL;
986 }
987
988 /* subsystems can specify simple device enumeration */
989 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
990 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
991
992 if (!dev_name(dev)) {
993 error = -EINVAL;
994 goto name_error;
995 }
996
997 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
998
999 parent = get_device(dev->parent);
1000 kobj = get_device_parent(dev, parent);
1001 if (kobj)
1002 dev->kobj.parent = kobj;
1003
1004 /* use parent numa_node */
1005 if (parent)
1006 set_dev_node(dev, dev_to_node(parent));
1007
1008 /* first, register with generic layer. */
1009 /* we require the name to be set before, and pass NULL */
1010 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
1011 if (error)
1012 goto Error;
1013
1014 /* notify platform of device entry */
1015 if (platform_notify)
1016 platform_notify(dev);
1017
1018 error = device_create_file(dev, &dev_attr_uevent);
1019 if (error)
1020 goto attrError;
1021
1022 if (MAJOR(dev->devt)) {
1023 error = device_create_file(dev, &dev_attr_dev);
1024 if (error)
1025 goto ueventattrError;
1026
1027 error = device_create_sys_dev_entry(dev);
1028 if (error)
1029 goto devtattrError;
1030
1031 devtmpfs_create_node(dev);
1032 }
1033
1034 error = device_add_class_symlinks(dev);
1035 if (error)
1036 goto SymlinkError;
1037 error = device_add_attrs(dev);
1038 if (error)
1039 goto AttrsError;
1040 error = bus_add_device(dev);
1041 if (error)
1042 goto BusError;
1043 error = dpm_sysfs_add(dev);
1044 if (error)
1045 goto DPMError;
1046 device_pm_add(dev);
1047
1048 /* Notify clients of device addition. This call must come
1049 * after dpm_sysfs_add() and before kobject_uevent().
1050 */
1051 if (dev->bus)
1052 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1053 BUS_NOTIFY_ADD_DEVICE, dev);
1054
1055 kobject_uevent(&dev->kobj, KOBJ_ADD);
1056 bus_probe_device(dev);
1057 if (parent)
1058 klist_add_tail(&dev->p->knode_parent,
1059 &parent->p->klist_children);
1060
1061 if (dev->class) {
1062 mutex_lock(&dev->class->p->mutex);
1063 /* tie the class to the device */
1064 klist_add_tail(&dev->knode_class,
1065 &dev->class->p->klist_devices);
1066
1067 /* notify any interfaces that the device is here */
1068 list_for_each_entry(class_intf,
1069 &dev->class->p->interfaces, node)
1070 if (class_intf->add_dev)
1071 class_intf->add_dev(dev, class_intf);
1072 mutex_unlock(&dev->class->p->mutex);
1073 }
1074done:
1075 put_device(dev);
1076 return error;
1077 DPMError:
1078 bus_remove_device(dev);
1079 BusError:
1080 device_remove_attrs(dev);
1081 AttrsError:
1082 device_remove_class_symlinks(dev);
1083 SymlinkError:
1084 if (MAJOR(dev->devt))
1085 devtmpfs_delete_node(dev);
1086 if (MAJOR(dev->devt))
1087 device_remove_sys_dev_entry(dev);
1088 devtattrError:
1089 if (MAJOR(dev->devt))
1090 device_remove_file(dev, &dev_attr_dev);
1091 ueventattrError:
1092 device_remove_file(dev, &dev_attr_uevent);
1093 attrError:
1094 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1095 kobject_del(&dev->kobj);
1096 Error:
1097 cleanup_device_parent(dev);
1098 if (parent)
1099 put_device(parent);
1100name_error:
1101 kfree(dev->p);
1102 dev->p = NULL;
1103 goto done;
1104}
1105EXPORT_SYMBOL_GPL(device_add);
1106
1107/**
1108 * device_register - register a device with the system.
1109 * @dev: pointer to the device structure
1110 *
1111 * This happens in two clean steps - initialize the device
1112 * and add it to the system. The two steps can be called
1113 * separately, but this is the easiest and most common.
1114 * I.e. you should only call the two helpers separately if
1115 * have a clearly defined need to use and refcount the device
1116 * before it is added to the hierarchy.
1117 *
1118 * For more information, see the kerneldoc for device_initialize()
1119 * and device_add().
1120 *
1121 * NOTE: _Never_ directly free @dev after calling this function, even
1122 * if it returned an error! Always use put_device() to give up the
1123 * reference initialized in this function instead.
1124 */
1125int device_register(struct device *dev)
1126{
1127 device_initialize(dev);
1128 return device_add(dev);
1129}
1130EXPORT_SYMBOL_GPL(device_register);
1131
1132/**
1133 * get_device - increment reference count for device.
1134 * @dev: device.
1135 *
1136 * This simply forwards the call to kobject_get(), though
1137 * we do take care to provide for the case that we get a NULL
1138 * pointer passed in.
1139 */
1140struct device *get_device(struct device *dev)
1141{
1142 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
1143}
1144EXPORT_SYMBOL_GPL(get_device);
1145
1146/**
1147 * put_device - decrement reference count.
1148 * @dev: device in question.
1149 */
1150void put_device(struct device *dev)
1151{
1152 /* might_sleep(); */
1153 if (dev)
1154 kobject_put(&dev->kobj);
1155}
1156EXPORT_SYMBOL_GPL(put_device);
1157
1158/**
1159 * device_del - delete device from system.
1160 * @dev: device.
1161 *
1162 * This is the first part of the device unregistration
1163 * sequence. This removes the device from the lists we control
1164 * from here, has it removed from the other driver model
1165 * subsystems it was added to in device_add(), and removes it
1166 * from the kobject hierarchy.
1167 *
1168 * NOTE: this should be called manually _iff_ device_add() was
1169 * also called manually.
1170 */
1171void device_del(struct device *dev)
1172{
1173 struct device *parent = dev->parent;
1174 struct class_interface *class_intf;
1175
1176 /* Notify clients of device removal. This call must come
1177 * before dpm_sysfs_remove().
1178 */
1179 if (dev->bus)
1180 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1181 BUS_NOTIFY_DEL_DEVICE, dev);
1182 dpm_sysfs_remove(dev);
1183 if (parent)
1184 klist_del(&dev->p->knode_parent);
1185 if (MAJOR(dev->devt)) {
1186 devtmpfs_delete_node(dev);
1187 device_remove_sys_dev_entry(dev);
1188 device_remove_file(dev, &dev_attr_dev);
1189 }
1190 if (dev->class) {
1191 device_remove_class_symlinks(dev);
1192
1193 mutex_lock(&dev->class->p->mutex);
1194 /* notify any interfaces that the device is now gone */
1195 list_for_each_entry(class_intf,
1196 &dev->class->p->interfaces, node)
1197 if (class_intf->remove_dev)
1198 class_intf->remove_dev(dev, class_intf);
1199 /* remove the device from the class list */
1200 klist_del(&dev->knode_class);
1201 mutex_unlock(&dev->class->p->mutex);
1202 }
1203 device_remove_file(dev, &dev_attr_uevent);
1204 device_remove_attrs(dev);
1205 bus_remove_device(dev);
1206 device_pm_remove(dev);
1207 driver_deferred_probe_del(dev);
1208
1209 /* Notify the platform of the removal, in case they
1210 * need to do anything...
1211 */
1212 if (platform_notify_remove)
1213 platform_notify_remove(dev);
1214 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1215 cleanup_device_parent(dev);
1216 kobject_del(&dev->kobj);
1217 put_device(parent);
1218}
1219EXPORT_SYMBOL_GPL(device_del);
1220
1221/**
1222 * device_unregister - unregister device from system.
1223 * @dev: device going away.
1224 *
1225 * We do this in two parts, like we do device_register(). First,
1226 * we remove it from all the subsystems with device_del(), then
1227 * we decrement the reference count via put_device(). If that
1228 * is the final reference count, the device will be cleaned up
1229 * via device_release() above. Otherwise, the structure will
1230 * stick around until the final reference to the device is dropped.
1231 */
1232void device_unregister(struct device *dev)
1233{
1234 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1235 device_del(dev);
1236 put_device(dev);
1237}
1238EXPORT_SYMBOL_GPL(device_unregister);
1239
1240static struct device *next_device(struct klist_iter *i)
1241{
1242 struct klist_node *n = klist_next(i);
1243 struct device *dev = NULL;
1244 struct device_private *p;
1245
1246 if (n) {
1247 p = to_device_private_parent(n);
1248 dev = p->device;
1249 }
1250 return dev;
1251}
1252
1253/**
1254 * device_get_devnode - path of device node file
1255 * @dev: device
1256 * @mode: returned file access mode
1257 * @uid: returned file owner
1258 * @gid: returned file group
1259 * @tmp: possibly allocated string
1260 *
1261 * Return the relative path of a possible device node.
1262 * Non-default names may need to allocate a memory to compose
1263 * a name. This memory is returned in tmp and needs to be
1264 * freed by the caller.
1265 */
1266const char *device_get_devnode(struct device *dev,
1267 umode_t *mode, kuid_t *uid, kgid_t *gid,
1268 const char **tmp)
1269{
1270 char *s;
1271
1272 *tmp = NULL;
1273
1274 /* the device type may provide a specific name */
1275 if (dev->type && dev->type->devnode)
1276 *tmp = dev->type->devnode(dev, mode, uid, gid);
1277 if (*tmp)
1278 return *tmp;
1279
1280 /* the class may provide a specific name */
1281 if (dev->class && dev->class->devnode)
1282 *tmp = dev->class->devnode(dev, mode);
1283 if (*tmp)
1284 return *tmp;
1285
1286 /* return name without allocation, tmp == NULL */
1287 if (strchr(dev_name(dev), '!') == NULL)
1288 return dev_name(dev);
1289
1290 /* replace '!' in the name with '/' */
1291 *tmp = kstrdup(dev_name(dev), GFP_KERNEL);
1292 if (!*tmp)
1293 return NULL;
1294 while ((s = strchr(*tmp, '!')))
1295 s[0] = '/';
1296 return *tmp;
1297}
1298
1299/**
1300 * device_for_each_child - device child iterator.
1301 * @parent: parent struct device.
1302 * @fn: function to be called for each device.
1303 * @data: data for the callback.
1304 *
1305 * Iterate over @parent's child devices, and call @fn for each,
1306 * passing it @data.
1307 *
1308 * We check the return of @fn each time. If it returns anything
1309 * other than 0, we break out and return that value.
1310 */
1311int device_for_each_child(struct device *parent, void *data,
1312 int (*fn)(struct device *dev, void *data))
1313{
1314 struct klist_iter i;
1315 struct device *child;
1316 int error = 0;
1317
1318 if (!parent->p)
1319 return 0;
1320
1321 klist_iter_init(&parent->p->klist_children, &i);
1322 while ((child = next_device(&i)) && !error)
1323 error = fn(child, data);
1324 klist_iter_exit(&i);
1325 return error;
1326}
1327EXPORT_SYMBOL_GPL(device_for_each_child);
1328
1329/**
1330 * device_find_child - device iterator for locating a particular device.
1331 * @parent: parent struct device
1332 * @match: Callback function to check device
1333 * @data: Data to pass to match function
1334 *
1335 * This is similar to the device_for_each_child() function above, but it
1336 * returns a reference to a device that is 'found' for later use, as
1337 * determined by the @match callback.
1338 *
1339 * The callback should return 0 if the device doesn't match and non-zero
1340 * if it does. If the callback returns non-zero and a reference to the
1341 * current device can be obtained, this function will return to the caller
1342 * and not iterate over any more devices.
1343 *
1344 * NOTE: you will need to drop the reference with put_device() after use.
1345 */
1346struct device *device_find_child(struct device *parent, void *data,
1347 int (*match)(struct device *dev, void *data))
1348{
1349 struct klist_iter i;
1350 struct device *child;
1351
1352 if (!parent)
1353 return NULL;
1354
1355 klist_iter_init(&parent->p->klist_children, &i);
1356 while ((child = next_device(&i)))
1357 if (match(child, data) && get_device(child))
1358 break;
1359 klist_iter_exit(&i);
1360 return child;
1361}
1362EXPORT_SYMBOL_GPL(device_find_child);
1363
1364int __init devices_init(void)
1365{
1366 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
1367 if (!devices_kset)
1368 return -ENOMEM;
1369 dev_kobj = kobject_create_and_add("dev", NULL);
1370 if (!dev_kobj)
1371 goto dev_kobj_err;
1372 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
1373 if (!sysfs_dev_block_kobj)
1374 goto block_kobj_err;
1375 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
1376 if (!sysfs_dev_char_kobj)
1377 goto char_kobj_err;
1378
1379 return 0;
1380
1381 char_kobj_err:
1382 kobject_put(sysfs_dev_block_kobj);
1383 block_kobj_err:
1384 kobject_put(dev_kobj);
1385 dev_kobj_err:
1386 kset_unregister(devices_kset);
1387 return -ENOMEM;
1388}
1389
1390static int device_check_offline(struct device *dev, void *not_used)
1391{
1392 int ret;
1393
1394 ret = device_for_each_child(dev, NULL, device_check_offline);
1395 if (ret)
1396 return ret;
1397
1398 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
1399}
1400
1401/**
1402 * device_offline - Prepare the device for hot-removal.
1403 * @dev: Device to be put offline.
1404 *
1405 * Execute the device bus type's .offline() callback, if present, to prepare
1406 * the device for a subsequent hot-removal. If that succeeds, the device must
1407 * not be used until either it is removed or its bus type's .online() callback
1408 * is executed.
1409 *
1410 * Call under device_hotplug_lock.
1411 */
1412int device_offline(struct device *dev)
1413{
1414 int ret;
1415
1416 if (dev->offline_disabled)
1417 return -EPERM;
1418
1419 ret = device_for_each_child(dev, NULL, device_check_offline);
1420 if (ret)
1421 return ret;
1422
1423 device_lock(dev);
1424 if (device_supports_offline(dev)) {
1425 if (dev->offline) {
1426 ret = 1;
1427 } else {
1428 ret = dev->bus->offline(dev);
1429 if (!ret) {
1430 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
1431 dev->offline = true;
1432 }
1433 }
1434 }
1435 device_unlock(dev);
1436
1437 return ret;
1438}
1439
1440/**
1441 * device_online - Put the device back online after successful device_offline().
1442 * @dev: Device to be put back online.
1443 *
1444 * If device_offline() has been successfully executed for @dev, but the device
1445 * has not been removed subsequently, execute its bus type's .online() callback
1446 * to indicate that the device can be used again.
1447 *
1448 * Call under device_hotplug_lock.
1449 */
1450int device_online(struct device *dev)
1451{
1452 int ret = 0;
1453
1454 device_lock(dev);
1455 if (device_supports_offline(dev)) {
1456 if (dev->offline) {
1457 ret = dev->bus->online(dev);
1458 if (!ret) {
1459 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
1460 dev->offline = false;
1461 }
1462 } else {
1463 ret = 1;
1464 }
1465 }
1466 device_unlock(dev);
1467
1468 return ret;
1469}
1470
1471struct root_device {
1472 struct device dev;
1473 struct module *owner;
1474};
1475
1476static inline struct root_device *to_root_device(struct device *d)
1477{
1478 return container_of(d, struct root_device, dev);
1479}
1480
1481static void root_device_release(struct device *dev)
1482{
1483 kfree(to_root_device(dev));
1484}
1485
1486/**
1487 * __root_device_register - allocate and register a root device
1488 * @name: root device name
1489 * @owner: owner module of the root device, usually THIS_MODULE
1490 *
1491 * This function allocates a root device and registers it
1492 * using device_register(). In order to free the returned
1493 * device, use root_device_unregister().
1494 *
1495 * Root devices are dummy devices which allow other devices
1496 * to be grouped under /sys/devices. Use this function to
1497 * allocate a root device and then use it as the parent of
1498 * any device which should appear under /sys/devices/{name}
1499 *
1500 * The /sys/devices/{name} directory will also contain a
1501 * 'module' symlink which points to the @owner directory
1502 * in sysfs.
1503 *
1504 * Returns &struct device pointer on success, or ERR_PTR() on error.
1505 *
1506 * Note: You probably want to use root_device_register().
1507 */
1508struct device *__root_device_register(const char *name, struct module *owner)
1509{
1510 struct root_device *root;
1511 int err = -ENOMEM;
1512
1513 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
1514 if (!root)
1515 return ERR_PTR(err);
1516
1517 err = dev_set_name(&root->dev, "%s", name);
1518 if (err) {
1519 kfree(root);
1520 return ERR_PTR(err);
1521 }
1522
1523 root->dev.release = root_device_release;
1524
1525 err = device_register(&root->dev);
1526 if (err) {
1527 put_device(&root->dev);
1528 return ERR_PTR(err);
1529 }
1530
1531#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
1532 if (owner) {
1533 struct module_kobject *mk = &owner->mkobj;
1534
1535 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
1536 if (err) {
1537 device_unregister(&root->dev);
1538 return ERR_PTR(err);
1539 }
1540 root->owner = owner;
1541 }
1542#endif
1543
1544 return &root->dev;
1545}
1546EXPORT_SYMBOL_GPL(__root_device_register);
1547
1548/**
1549 * root_device_unregister - unregister and free a root device
1550 * @dev: device going away
1551 *
1552 * This function unregisters and cleans up a device that was created by
1553 * root_device_register().
1554 */
1555void root_device_unregister(struct device *dev)
1556{
1557 struct root_device *root = to_root_device(dev);
1558
1559 if (root->owner)
1560 sysfs_remove_link(&root->dev.kobj, "module");
1561
1562 device_unregister(dev);
1563}
1564EXPORT_SYMBOL_GPL(root_device_unregister);
1565
1566
1567static void device_create_release(struct device *dev)
1568{
1569 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1570 kfree(dev);
1571}
1572
1573static struct device *
1574device_create_groups_vargs(struct class *class, struct device *parent,
1575 dev_t devt, void *drvdata,
1576 const struct attribute_group **groups,
1577 const char *fmt, va_list args)
1578{
1579 struct device *dev = NULL;
1580 int retval = -ENODEV;
1581
1582 if (class == NULL || IS_ERR(class))
1583 goto error;
1584
1585 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1586 if (!dev) {
1587 retval = -ENOMEM;
1588 goto error;
1589 }
1590
1591 device_initialize(dev);
1592 dev->devt = devt;
1593 dev->class = class;
1594 dev->parent = parent;
1595 dev->groups = groups;
1596 dev->release = device_create_release;
1597 dev_set_drvdata(dev, drvdata);
1598
1599 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
1600 if (retval)
1601 goto error;
1602
1603 retval = device_add(dev);
1604 if (retval)
1605 goto error;
1606
1607 return dev;
1608
1609error:
1610 put_device(dev);
1611 return ERR_PTR(retval);
1612}
1613
1614/**
1615 * device_create_vargs - creates a device and registers it with sysfs
1616 * @class: pointer to the struct class that this device should be registered to
1617 * @parent: pointer to the parent struct device of this new device, if any
1618 * @devt: the dev_t for the char device to be added
1619 * @drvdata: the data to be added to the device for callbacks
1620 * @fmt: string for the device's name
1621 * @args: va_list for the device's name
1622 *
1623 * This function can be used by char device classes. A struct device
1624 * will be created in sysfs, registered to the specified class.
1625 *
1626 * A "dev" file will be created, showing the dev_t for the device, if
1627 * the dev_t is not 0,0.
1628 * If a pointer to a parent struct device is passed in, the newly created
1629 * struct device will be a child of that device in sysfs.
1630 * The pointer to the struct device will be returned from the call.
1631 * Any further sysfs files that might be required can be created using this
1632 * pointer.
1633 *
1634 * Returns &struct device pointer on success, or ERR_PTR() on error.
1635 *
1636 * Note: the struct class passed to this function must have previously
1637 * been created with a call to class_create().
1638 */
1639struct device *device_create_vargs(struct class *class, struct device *parent,
1640 dev_t devt, void *drvdata, const char *fmt,
1641 va_list args)
1642{
1643 return device_create_groups_vargs(class, parent, devt, drvdata, NULL,
1644 fmt, args);
1645}
1646EXPORT_SYMBOL_GPL(device_create_vargs);
1647
1648/**
1649 * device_create - creates a device and registers it with sysfs
1650 * @class: pointer to the struct class that this device should be registered to
1651 * @parent: pointer to the parent struct device of this new device, if any
1652 * @devt: the dev_t for the char device to be added
1653 * @drvdata: the data to be added to the device for callbacks
1654 * @fmt: string for the device's name
1655 *
1656 * This function can be used by char device classes. A struct device
1657 * will be created in sysfs, registered to the specified class.
1658 *
1659 * A "dev" file will be created, showing the dev_t for the device, if
1660 * the dev_t is not 0,0.
1661 * If a pointer to a parent struct device is passed in, the newly created
1662 * struct device will be a child of that device in sysfs.
1663 * The pointer to the struct device will be returned from the call.
1664 * Any further sysfs files that might be required can be created using this
1665 * pointer.
1666 *
1667 * Returns &struct device pointer on success, or ERR_PTR() on error.
1668 *
1669 * Note: the struct class passed to this function must have previously
1670 * been created with a call to class_create().
1671 */
1672struct device *device_create(struct class *class, struct device *parent,
1673 dev_t devt, void *drvdata, const char *fmt, ...)
1674{
1675 va_list vargs;
1676 struct device *dev;
1677
1678 va_start(vargs, fmt);
1679 dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
1680 va_end(vargs);
1681 return dev;
1682}
1683EXPORT_SYMBOL_GPL(device_create);
1684
1685/**
1686 * device_create_with_groups - creates a device and registers it with sysfs
1687 * @class: pointer to the struct class that this device should be registered to
1688 * @parent: pointer to the parent struct device of this new device, if any
1689 * @devt: the dev_t for the char device to be added
1690 * @drvdata: the data to be added to the device for callbacks
1691 * @groups: NULL-terminated list of attribute groups to be created
1692 * @fmt: string for the device's name
1693 *
1694 * This function can be used by char device classes. A struct device
1695 * will be created in sysfs, registered to the specified class.
1696 * Additional attributes specified in the groups parameter will also
1697 * be created automatically.
1698 *
1699 * A "dev" file will be created, showing the dev_t for the device, if
1700 * the dev_t is not 0,0.
1701 * If a pointer to a parent struct device is passed in, the newly created
1702 * struct device will be a child of that device in sysfs.
1703 * The pointer to the struct device will be returned from the call.
1704 * Any further sysfs files that might be required can be created using this
1705 * pointer.
1706 *
1707 * Returns &struct device pointer on success, or ERR_PTR() on error.
1708 *
1709 * Note: the struct class passed to this function must have previously
1710 * been created with a call to class_create().
1711 */
1712struct device *device_create_with_groups(struct class *class,
1713 struct device *parent, dev_t devt,
1714 void *drvdata,
1715 const struct attribute_group **groups,
1716 const char *fmt, ...)
1717{
1718 va_list vargs;
1719 struct device *dev;
1720
1721 va_start(vargs, fmt);
1722 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
1723 fmt, vargs);
1724 va_end(vargs);
1725 return dev;
1726}
1727EXPORT_SYMBOL_GPL(device_create_with_groups);
1728
1729static int __match_devt(struct device *dev, const void *data)
1730{
1731 const dev_t *devt = data;
1732
1733 return dev->devt == *devt;
1734}
1735
1736/**
1737 * device_destroy - removes a device that was created with device_create()
1738 * @class: pointer to the struct class that this device was registered with
1739 * @devt: the dev_t of the device that was previously registered
1740 *
1741 * This call unregisters and cleans up a device that was created with a
1742 * call to device_create().
1743 */
1744void device_destroy(struct class *class, dev_t devt)
1745{
1746 struct device *dev;
1747
1748 dev = class_find_device(class, NULL, &devt, __match_devt);
1749 if (dev) {
1750 put_device(dev);
1751 device_unregister(dev);
1752 }
1753}
1754EXPORT_SYMBOL_GPL(device_destroy);
1755
1756/**
1757 * device_rename - renames a device
1758 * @dev: the pointer to the struct device to be renamed
1759 * @new_name: the new name of the device
1760 *
1761 * It is the responsibility of the caller to provide mutual
1762 * exclusion between two different calls of device_rename
1763 * on the same device to ensure that new_name is valid and
1764 * won't conflict with other devices.
1765 *
1766 * Note: Don't call this function. Currently, the networking layer calls this
1767 * function, but that will change. The following text from Kay Sievers offers
1768 * some insight:
1769 *
1770 * Renaming devices is racy at many levels, symlinks and other stuff are not
1771 * replaced atomically, and you get a "move" uevent, but it's not easy to
1772 * connect the event to the old and new device. Device nodes are not renamed at
1773 * all, there isn't even support for that in the kernel now.
1774 *
1775 * In the meantime, during renaming, your target name might be taken by another
1776 * driver, creating conflicts. Or the old name is taken directly after you
1777 * renamed it -- then you get events for the same DEVPATH, before you even see
1778 * the "move" event. It's just a mess, and nothing new should ever rely on
1779 * kernel device renaming. Besides that, it's not even implemented now for
1780 * other things than (driver-core wise very simple) network devices.
1781 *
1782 * We are currently about to change network renaming in udev to completely
1783 * disallow renaming of devices in the same namespace as the kernel uses,
1784 * because we can't solve the problems properly, that arise with swapping names
1785 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
1786 * be allowed to some other name than eth[0-9]*, for the aforementioned
1787 * reasons.
1788 *
1789 * Make up a "real" name in the driver before you register anything, or add
1790 * some other attributes for userspace to find the device, or use udev to add
1791 * symlinks -- but never rename kernel devices later, it's a complete mess. We
1792 * don't even want to get into that and try to implement the missing pieces in
1793 * the core. We really have other pieces to fix in the driver core mess. :)
1794 */
1795int device_rename(struct device *dev, const char *new_name)
1796{
1797 struct kobject *kobj = &dev->kobj;
1798 char *old_device_name = NULL;
1799 int error;
1800
1801 dev = get_device(dev);
1802 if (!dev)
1803 return -EINVAL;
1804
1805 dev_dbg(dev, "renaming to %s\n", new_name);
1806
1807 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1808 if (!old_device_name) {
1809 error = -ENOMEM;
1810 goto out;
1811 }
1812
1813 if (dev->class) {
1814 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
1815 kobj, old_device_name,
1816 new_name, kobject_namespace(kobj));
1817 if (error)
1818 goto out;
1819 }
1820
1821 error = kobject_rename(kobj, new_name);
1822 if (error)
1823 goto out;
1824
1825out:
1826 put_device(dev);
1827
1828 kfree(old_device_name);
1829
1830 return error;
1831}
1832EXPORT_SYMBOL_GPL(device_rename);
1833
1834static int device_move_class_links(struct device *dev,
1835 struct device *old_parent,
1836 struct device *new_parent)
1837{
1838 int error = 0;
1839
1840 if (old_parent)
1841 sysfs_remove_link(&dev->kobj, "device");
1842 if (new_parent)
1843 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1844 "device");
1845 return error;
1846}
1847
1848/**
1849 * device_move - moves a device to a new parent
1850 * @dev: the pointer to the struct device to be moved
1851 * @new_parent: the new parent of the device (can by NULL)
1852 * @dpm_order: how to reorder the dpm_list
1853 */
1854int device_move(struct device *dev, struct device *new_parent,
1855 enum dpm_order dpm_order)
1856{
1857 int error;
1858 struct device *old_parent;
1859 struct kobject *new_parent_kobj;
1860
1861 dev = get_device(dev);
1862 if (!dev)
1863 return -EINVAL;
1864
1865 device_pm_lock();
1866 new_parent = get_device(new_parent);
1867 new_parent_kobj = get_device_parent(dev, new_parent);
1868
1869 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
1870 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1871 error = kobject_move(&dev->kobj, new_parent_kobj);
1872 if (error) {
1873 cleanup_glue_dir(dev, new_parent_kobj);
1874 put_device(new_parent);
1875 goto out;
1876 }
1877 old_parent = dev->parent;
1878 dev->parent = new_parent;
1879 if (old_parent)
1880 klist_remove(&dev->p->knode_parent);
1881 if (new_parent) {
1882 klist_add_tail(&dev->p->knode_parent,
1883 &new_parent->p->klist_children);
1884 set_dev_node(dev, dev_to_node(new_parent));
1885 }
1886
1887 if (dev->class) {
1888 error = device_move_class_links(dev, old_parent, new_parent);
1889 if (error) {
1890 /* We ignore errors on cleanup since we're hosed anyway... */
1891 device_move_class_links(dev, new_parent, old_parent);
1892 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1893 if (new_parent)
1894 klist_remove(&dev->p->knode_parent);
1895 dev->parent = old_parent;
1896 if (old_parent) {
1897 klist_add_tail(&dev->p->knode_parent,
1898 &old_parent->p->klist_children);
1899 set_dev_node(dev, dev_to_node(old_parent));
1900 }
1901 }
1902 cleanup_glue_dir(dev, new_parent_kobj);
1903 put_device(new_parent);
1904 goto out;
1905 }
1906 }
1907 switch (dpm_order) {
1908 case DPM_ORDER_NONE:
1909 break;
1910 case DPM_ORDER_DEV_AFTER_PARENT:
1911 device_pm_move_after(dev, new_parent);
1912 break;
1913 case DPM_ORDER_PARENT_BEFORE_DEV:
1914 device_pm_move_before(new_parent, dev);
1915 break;
1916 case DPM_ORDER_DEV_LAST:
1917 device_pm_move_last(dev);
1918 break;
1919 }
1920
1921 put_device(old_parent);
1922out:
1923 device_pm_unlock();
1924 put_device(dev);
1925 return error;
1926}
1927EXPORT_SYMBOL_GPL(device_move);
1928
1929/**
1930 * device_shutdown - call ->shutdown() on each device to shutdown.
1931 */
1932void device_shutdown(void)
1933{
1934 struct device *dev, *parent;
1935
1936 spin_lock(&devices_kset->list_lock);
1937 /*
1938 * Walk the devices list backward, shutting down each in turn.
1939 * Beware that device unplug events may also start pulling
1940 * devices offline, even as the system is shutting down.
1941 */
1942 while (!list_empty(&devices_kset->list)) {
1943 dev = list_entry(devices_kset->list.prev, struct device,
1944 kobj.entry);
1945
1946 /*
1947 * hold reference count of device's parent to
1948 * prevent it from being freed because parent's
1949 * lock is to be held
1950 */
1951 parent = get_device(dev->parent);
1952 get_device(dev);
1953 /*
1954 * Make sure the device is off the kset list, in the
1955 * event that dev->*->shutdown() doesn't remove it.
1956 */
1957 list_del_init(&dev->kobj.entry);
1958 spin_unlock(&devices_kset->list_lock);
1959
1960 /* hold lock to avoid race with probe/release */
1961 if (parent)
1962 device_lock(parent);
1963 device_lock(dev);
1964
1965 /* Don't allow any more runtime suspends */
1966 pm_runtime_get_noresume(dev);
1967 pm_runtime_barrier(dev);
1968
1969 if (dev->bus && dev->bus->shutdown) {
1970 if (initcall_debug)
1971 dev_info(dev, "shutdown\n");
1972 dev->bus->shutdown(dev);
1973 } else if (dev->driver && dev->driver->shutdown) {
1974 if (initcall_debug)
1975 dev_info(dev, "shutdown\n");
1976 dev->driver->shutdown(dev);
1977 }
1978
1979 device_unlock(dev);
1980 if (parent)
1981 device_unlock(parent);
1982
1983 put_device(dev);
1984 put_device(parent);
1985
1986 spin_lock(&devices_kset->list_lock);
1987 }
1988 spin_unlock(&devices_kset->list_lock);
1989}
1990
1991/*
1992 * Device logging functions
1993 */
1994
1995#ifdef CONFIG_PRINTK
1996static int
1997create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
1998{
1999 const char *subsys;
2000 size_t pos = 0;
2001
2002 if (dev->class)
2003 subsys = dev->class->name;
2004 else if (dev->bus)
2005 subsys = dev->bus->name;
2006 else
2007 return 0;
2008
2009 pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
2010
2011 /*
2012 * Add device identifier DEVICE=:
2013 * b12:8 block dev_t
2014 * c127:3 char dev_t
2015 * n8 netdev ifindex
2016 * +sound:card0 subsystem:devname
2017 */
2018 if (MAJOR(dev->devt)) {
2019 char c;
2020
2021 if (strcmp(subsys, "block") == 0)
2022 c = 'b';
2023 else
2024 c = 'c';
2025 pos++;
2026 pos += snprintf(hdr + pos, hdrlen - pos,
2027 "DEVICE=%c%u:%u",
2028 c, MAJOR(dev->devt), MINOR(dev->devt));
2029 } else if (strcmp(subsys, "net") == 0) {
2030 struct net_device *net = to_net_dev(dev);
2031
2032 pos++;
2033 pos += snprintf(hdr + pos, hdrlen - pos,
2034 "DEVICE=n%u", net->ifindex);
2035 } else {
2036 pos++;
2037 pos += snprintf(hdr + pos, hdrlen - pos,
2038 "DEVICE=+%s:%s", subsys, dev_name(dev));
2039 }
2040
2041 return pos;
2042}
2043
2044int dev_vprintk_emit(int level, const struct device *dev,
2045 const char *fmt, va_list args)
2046{
2047 char hdr[128];
2048 size_t hdrlen;
2049
2050 hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
2051
2052 return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
2053}
2054EXPORT_SYMBOL(dev_vprintk_emit);
2055
2056int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
2057{
2058 va_list args;
2059 int r;
2060
2061 va_start(args, fmt);
2062
2063 r = dev_vprintk_emit(level, dev, fmt, args);
2064
2065 va_end(args);
2066
2067 return r;
2068}
2069EXPORT_SYMBOL(dev_printk_emit);
2070
2071static int __dev_printk(const char *level, const struct device *dev,
2072 struct va_format *vaf)
2073{
2074 if (!dev)
2075 return printk("%s(NULL device *): %pV", level, vaf);
2076
2077 return dev_printk_emit(level[1] - '0', dev,
2078 "%s %s: %pV",
2079 dev_driver_string(dev), dev_name(dev), vaf);
2080}
2081
2082int dev_printk(const char *level, const struct device *dev,
2083 const char *fmt, ...)
2084{
2085 struct va_format vaf;
2086 va_list args;
2087 int r;
2088
2089 va_start(args, fmt);
2090
2091 vaf.fmt = fmt;
2092 vaf.va = &args;
2093
2094 r = __dev_printk(level, dev, &vaf);
2095
2096 va_end(args);
2097
2098 return r;
2099}
2100EXPORT_SYMBOL(dev_printk);
2101
2102#define define_dev_printk_level(func, kern_level) \
2103int func(const struct device *dev, const char *fmt, ...) \
2104{ \
2105 struct va_format vaf; \
2106 va_list args; \
2107 int r; \
2108 \
2109 va_start(args, fmt); \
2110 \
2111 vaf.fmt = fmt; \
2112 vaf.va = &args; \
2113 \
2114 r = __dev_printk(kern_level, dev, &vaf); \
2115 \
2116 va_end(args); \
2117 \
2118 return r; \
2119} \
2120EXPORT_SYMBOL(func);
2121
2122define_dev_printk_level(dev_emerg, KERN_EMERG);
2123define_dev_printk_level(dev_alert, KERN_ALERT);
2124define_dev_printk_level(dev_crit, KERN_CRIT);
2125define_dev_printk_level(dev_err, KERN_ERR);
2126define_dev_printk_level(dev_warn, KERN_WARNING);
2127define_dev_printk_level(dev_notice, KERN_NOTICE);
2128define_dev_printk_level(_dev_info, KERN_INFO);
2129
2130#endif