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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/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/kallsyms.h>
26#include <linux/mutex.h>
27#include <linux/pm_runtime.h>
28#include <linux/netdevice.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. */
48
49#ifdef CONFIG_SRCU
50static DEFINE_MUTEX(device_links_lock);
51DEFINE_STATIC_SRCU(device_links_srcu);
52
53static inline void device_links_write_lock(void)
54{
55 mutex_lock(&device_links_lock);
56}
57
58static inline void device_links_write_unlock(void)
59{
60 mutex_unlock(&device_links_lock);
61}
62
63int device_links_read_lock(void)
64{
65 return srcu_read_lock(&device_links_srcu);
66}
67
68void device_links_read_unlock(int idx)
69{
70 srcu_read_unlock(&device_links_srcu, idx);
71}
72#else /* !CONFIG_SRCU */
73static DECLARE_RWSEM(device_links_lock);
74
75static inline void device_links_write_lock(void)
76{
77 down_write(&device_links_lock);
78}
79
80static inline void device_links_write_unlock(void)
81{
82 up_write(&device_links_lock);
83}
84
85int device_links_read_lock(void)
86{
87 down_read(&device_links_lock);
88 return 0;
89}
90
91void device_links_read_unlock(int not_used)
92{
93 up_read(&device_links_lock);
94}
95#endif /* !CONFIG_SRCU */
96
97/**
98 * device_is_dependent - Check if one device depends on another one
99 * @dev: Device to check dependencies for.
100 * @target: Device to check against.
101 *
102 * Check if @target depends on @dev or any device dependent on it (its child or
103 * its consumer etc). Return 1 if that is the case or 0 otherwise.
104 */
105static int device_is_dependent(struct device *dev, void *target)
106{
107 struct device_link *link;
108 int ret;
109
110 if (WARN_ON(dev == target))
111 return 1;
112
113 ret = device_for_each_child(dev, target, device_is_dependent);
114 if (ret)
115 return ret;
116
117 list_for_each_entry(link, &dev->links.consumers, s_node) {
118 if (WARN_ON(link->consumer == target))
119 return 1;
120
121 ret = device_is_dependent(link->consumer, target);
122 if (ret)
123 break;
124 }
125 return ret;
126}
127
128static int device_reorder_to_tail(struct device *dev, void *not_used)
129{
130 struct device_link *link;
131
132 /*
133 * Devices that have not been registered yet will be put to the ends
134 * of the lists during the registration, so skip them here.
135 */
136 if (device_is_registered(dev))
137 devices_kset_move_last(dev);
138
139 if (device_pm_initialized(dev))
140 device_pm_move_last(dev);
141
142 device_for_each_child(dev, NULL, device_reorder_to_tail);
143 list_for_each_entry(link, &dev->links.consumers, s_node)
144 device_reorder_to_tail(link->consumer, NULL);
145
146 return 0;
147}
148
149/**
150 * device_link_add - Create a link between two devices.
151 * @consumer: Consumer end of the link.
152 * @supplier: Supplier end of the link.
153 * @flags: Link flags.
154 *
155 * The caller is responsible for the proper synchronization of the link creation
156 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
157 * runtime PM framework to take the link into account. Second, if the
158 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
159 * be forced into the active metastate and reference-counted upon the creation
160 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
161 * ignored.
162 *
163 * If the DL_FLAG_AUTOREMOVE is set, the link will be removed automatically
164 * when the consumer device driver unbinds from it. The combination of both
165 * DL_FLAG_AUTOREMOVE and DL_FLAG_STATELESS set is invalid and will cause NULL
166 * to be returned.
167 *
168 * A side effect of the link creation is re-ordering of dpm_list and the
169 * devices_kset list by moving the consumer device and all devices depending
170 * on it to the ends of these lists (that does not happen to devices that have
171 * not been registered when this function is called).
172 *
173 * The supplier device is required to be registered when this function is called
174 * and NULL will be returned if that is not the case. The consumer device need
175 * not be registered, however.
176 */
177struct device_link *device_link_add(struct device *consumer,
178 struct device *supplier, u32 flags)
179{
180 struct device_link *link;
181
182 if (!consumer || !supplier ||
183 ((flags & DL_FLAG_STATELESS) && (flags & DL_FLAG_AUTOREMOVE)))
184 return NULL;
185
186 device_links_write_lock();
187 device_pm_lock();
188
189 /*
190 * If the supplier has not been fully registered yet or there is a
191 * reverse dependency between the consumer and the supplier already in
192 * the graph, return NULL.
193 */
194 if (!device_pm_initialized(supplier)
195 || device_is_dependent(consumer, supplier)) {
196 link = NULL;
197 goto out;
198 }
199
200 list_for_each_entry(link, &supplier->links.consumers, s_node)
201 if (link->consumer == consumer)
202 goto out;
203
204 link = kzalloc(sizeof(*link), GFP_KERNEL);
205 if (!link)
206 goto out;
207
208 if (flags & DL_FLAG_PM_RUNTIME) {
209 if (flags & DL_FLAG_RPM_ACTIVE) {
210 if (pm_runtime_get_sync(supplier) < 0) {
211 pm_runtime_put_noidle(supplier);
212 kfree(link);
213 link = NULL;
214 goto out;
215 }
216 link->rpm_active = true;
217 }
218 pm_runtime_new_link(consumer);
219 }
220 get_device(supplier);
221 link->supplier = supplier;
222 INIT_LIST_HEAD(&link->s_node);
223 get_device(consumer);
224 link->consumer = consumer;
225 INIT_LIST_HEAD(&link->c_node);
226 link->flags = flags;
227
228 /* Determine the initial link state. */
229 if (flags & DL_FLAG_STATELESS) {
230 link->status = DL_STATE_NONE;
231 } else {
232 switch (supplier->links.status) {
233 case DL_DEV_DRIVER_BOUND:
234 switch (consumer->links.status) {
235 case DL_DEV_PROBING:
236 /*
237 * Balance the decrementation of the supplier's
238 * runtime PM usage counter after consumer probe
239 * in driver_probe_device().
240 */
241 if (flags & DL_FLAG_PM_RUNTIME)
242 pm_runtime_get_sync(supplier);
243
244 link->status = DL_STATE_CONSUMER_PROBE;
245 break;
246 case DL_DEV_DRIVER_BOUND:
247 link->status = DL_STATE_ACTIVE;
248 break;
249 default:
250 link->status = DL_STATE_AVAILABLE;
251 break;
252 }
253 break;
254 case DL_DEV_UNBINDING:
255 link->status = DL_STATE_SUPPLIER_UNBIND;
256 break;
257 default:
258 link->status = DL_STATE_DORMANT;
259 break;
260 }
261 }
262
263 /*
264 * Move the consumer and all of the devices depending on it to the end
265 * of dpm_list and the devices_kset list.
266 *
267 * It is necessary to hold dpm_list locked throughout all that or else
268 * we may end up suspending with a wrong ordering of it.
269 */
270 device_reorder_to_tail(consumer, NULL);
271
272 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
273 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
274
275 dev_info(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
276
277 out:
278 device_pm_unlock();
279 device_links_write_unlock();
280 return link;
281}
282EXPORT_SYMBOL_GPL(device_link_add);
283
284static void device_link_free(struct device_link *link)
285{
286 put_device(link->consumer);
287 put_device(link->supplier);
288 kfree(link);
289}
290
291#ifdef CONFIG_SRCU
292static void __device_link_free_srcu(struct rcu_head *rhead)
293{
294 device_link_free(container_of(rhead, struct device_link, rcu_head));
295}
296
297static void __device_link_del(struct device_link *link)
298{
299 dev_info(link->consumer, "Dropping the link to %s\n",
300 dev_name(link->supplier));
301
302 if (link->flags & DL_FLAG_PM_RUNTIME)
303 pm_runtime_drop_link(link->consumer);
304
305 list_del_rcu(&link->s_node);
306 list_del_rcu(&link->c_node);
307 call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
308}
309#else /* !CONFIG_SRCU */
310static void __device_link_del(struct device_link *link)
311{
312 dev_info(link->consumer, "Dropping the link to %s\n",
313 dev_name(link->supplier));
314
315 list_del(&link->s_node);
316 list_del(&link->c_node);
317 device_link_free(link);
318}
319#endif /* !CONFIG_SRCU */
320
321/**
322 * device_link_del - Delete a link between two devices.
323 * @link: Device link to delete.
324 *
325 * The caller must ensure proper synchronization of this function with runtime
326 * PM.
327 */
328void device_link_del(struct device_link *link)
329{
330 device_links_write_lock();
331 device_pm_lock();
332 __device_link_del(link);
333 device_pm_unlock();
334 device_links_write_unlock();
335}
336EXPORT_SYMBOL_GPL(device_link_del);
337
338static void device_links_missing_supplier(struct device *dev)
339{
340 struct device_link *link;
341
342 list_for_each_entry(link, &dev->links.suppliers, c_node)
343 if (link->status == DL_STATE_CONSUMER_PROBE)
344 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
345}
346
347/**
348 * device_links_check_suppliers - Check presence of supplier drivers.
349 * @dev: Consumer device.
350 *
351 * Check links from this device to any suppliers. Walk the list of the device's
352 * links to suppliers and see if all of them are available. If not, simply
353 * return -EPROBE_DEFER.
354 *
355 * We need to guarantee that the supplier will not go away after the check has
356 * been positive here. It only can go away in __device_release_driver() and
357 * that function checks the device's links to consumers. This means we need to
358 * mark the link as "consumer probe in progress" to make the supplier removal
359 * wait for us to complete (or bad things may happen).
360 *
361 * Links with the DL_FLAG_STATELESS flag set are ignored.
362 */
363int device_links_check_suppliers(struct device *dev)
364{
365 struct device_link *link;
366 int ret = 0;
367
368 device_links_write_lock();
369
370 list_for_each_entry(link, &dev->links.suppliers, c_node) {
371 if (link->flags & DL_FLAG_STATELESS)
372 continue;
373
374 if (link->status != DL_STATE_AVAILABLE) {
375 device_links_missing_supplier(dev);
376 ret = -EPROBE_DEFER;
377 break;
378 }
379 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
380 }
381 dev->links.status = DL_DEV_PROBING;
382
383 device_links_write_unlock();
384 return ret;
385}
386
387/**
388 * device_links_driver_bound - Update device links after probing its driver.
389 * @dev: Device to update the links for.
390 *
391 * The probe has been successful, so update links from this device to any
392 * consumers by changing their status to "available".
393 *
394 * Also change the status of @dev's links to suppliers to "active".
395 *
396 * Links with the DL_FLAG_STATELESS flag set are ignored.
397 */
398void device_links_driver_bound(struct device *dev)
399{
400 struct device_link *link;
401
402 device_links_write_lock();
403
404 list_for_each_entry(link, &dev->links.consumers, s_node) {
405 if (link->flags & DL_FLAG_STATELESS)
406 continue;
407
408 WARN_ON(link->status != DL_STATE_DORMANT);
409 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
410 }
411
412 list_for_each_entry(link, &dev->links.suppliers, c_node) {
413 if (link->flags & DL_FLAG_STATELESS)
414 continue;
415
416 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
417 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
418 }
419
420 dev->links.status = DL_DEV_DRIVER_BOUND;
421
422 device_links_write_unlock();
423}
424
425/**
426 * __device_links_no_driver - Update links of a device without a driver.
427 * @dev: Device without a drvier.
428 *
429 * Delete all non-persistent links from this device to any suppliers.
430 *
431 * Persistent links stay around, but their status is changed to "available",
432 * unless they already are in the "supplier unbind in progress" state in which
433 * case they need not be updated.
434 *
435 * Links with the DL_FLAG_STATELESS flag set are ignored.
436 */
437static void __device_links_no_driver(struct device *dev)
438{
439 struct device_link *link, *ln;
440
441 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
442 if (link->flags & DL_FLAG_STATELESS)
443 continue;
444
445 if (link->flags & DL_FLAG_AUTOREMOVE)
446 __device_link_del(link);
447 else if (link->status != DL_STATE_SUPPLIER_UNBIND)
448 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
449 }
450
451 dev->links.status = DL_DEV_NO_DRIVER;
452}
453
454void device_links_no_driver(struct device *dev)
455{
456 device_links_write_lock();
457 __device_links_no_driver(dev);
458 device_links_write_unlock();
459}
460
461/**
462 * device_links_driver_cleanup - Update links after driver removal.
463 * @dev: Device whose driver has just gone away.
464 *
465 * Update links to consumers for @dev by changing their status to "dormant" and
466 * invoke %__device_links_no_driver() to update links to suppliers for it as
467 * appropriate.
468 *
469 * Links with the DL_FLAG_STATELESS flag set are ignored.
470 */
471void device_links_driver_cleanup(struct device *dev)
472{
473 struct device_link *link;
474
475 device_links_write_lock();
476
477 list_for_each_entry(link, &dev->links.consumers, s_node) {
478 if (link->flags & DL_FLAG_STATELESS)
479 continue;
480
481 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE);
482 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
483 WRITE_ONCE(link->status, DL_STATE_DORMANT);
484 }
485
486 __device_links_no_driver(dev);
487
488 device_links_write_unlock();
489}
490
491/**
492 * device_links_busy - Check if there are any busy links to consumers.
493 * @dev: Device to check.
494 *
495 * Check each consumer of the device and return 'true' if its link's status
496 * is one of "consumer probe" or "active" (meaning that the given consumer is
497 * probing right now or its driver is present). Otherwise, change the link
498 * state to "supplier unbind" to prevent the consumer from being probed
499 * successfully going forward.
500 *
501 * Return 'false' if there are no probing or active consumers.
502 *
503 * Links with the DL_FLAG_STATELESS flag set are ignored.
504 */
505bool device_links_busy(struct device *dev)
506{
507 struct device_link *link;
508 bool ret = false;
509
510 device_links_write_lock();
511
512 list_for_each_entry(link, &dev->links.consumers, s_node) {
513 if (link->flags & DL_FLAG_STATELESS)
514 continue;
515
516 if (link->status == DL_STATE_CONSUMER_PROBE
517 || link->status == DL_STATE_ACTIVE) {
518 ret = true;
519 break;
520 }
521 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
522 }
523
524 dev->links.status = DL_DEV_UNBINDING;
525
526 device_links_write_unlock();
527 return ret;
528}
529
530/**
531 * device_links_unbind_consumers - Force unbind consumers of the given device.
532 * @dev: Device to unbind the consumers of.
533 *
534 * Walk the list of links to consumers for @dev and if any of them is in the
535 * "consumer probe" state, wait for all device probes in progress to complete
536 * and start over.
537 *
538 * If that's not the case, change the status of the link to "supplier unbind"
539 * and check if the link was in the "active" state. If so, force the consumer
540 * driver to unbind and start over (the consumer will not re-probe as we have
541 * changed the state of the link already).
542 *
543 * Links with the DL_FLAG_STATELESS flag set are ignored.
544 */
545void device_links_unbind_consumers(struct device *dev)
546{
547 struct device_link *link;
548
549 start:
550 device_links_write_lock();
551
552 list_for_each_entry(link, &dev->links.consumers, s_node) {
553 enum device_link_state status;
554
555 if (link->flags & DL_FLAG_STATELESS)
556 continue;
557
558 status = link->status;
559 if (status == DL_STATE_CONSUMER_PROBE) {
560 device_links_write_unlock();
561
562 wait_for_device_probe();
563 goto start;
564 }
565 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
566 if (status == DL_STATE_ACTIVE) {
567 struct device *consumer = link->consumer;
568
569 get_device(consumer);
570
571 device_links_write_unlock();
572
573 device_release_driver_internal(consumer, NULL,
574 consumer->parent);
575 put_device(consumer);
576 goto start;
577 }
578 }
579
580 device_links_write_unlock();
581}
582
583/**
584 * device_links_purge - Delete existing links to other devices.
585 * @dev: Target device.
586 */
587static void device_links_purge(struct device *dev)
588{
589 struct device_link *link, *ln;
590
591 /*
592 * Delete all of the remaining links from this device to any other
593 * devices (either consumers or suppliers).
594 */
595 device_links_write_lock();
596
597 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
598 WARN_ON(link->status == DL_STATE_ACTIVE);
599 __device_link_del(link);
600 }
601
602 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
603 WARN_ON(link->status != DL_STATE_DORMANT &&
604 link->status != DL_STATE_NONE);
605 __device_link_del(link);
606 }
607
608 device_links_write_unlock();
609}
610
611/* Device links support end. */
612
613int (*platform_notify)(struct device *dev) = NULL;
614int (*platform_notify_remove)(struct device *dev) = NULL;
615static struct kobject *dev_kobj;
616struct kobject *sysfs_dev_char_kobj;
617struct kobject *sysfs_dev_block_kobj;
618
619static DEFINE_MUTEX(device_hotplug_lock);
620
621void lock_device_hotplug(void)
622{
623 mutex_lock(&device_hotplug_lock);
624}
625
626void unlock_device_hotplug(void)
627{
628 mutex_unlock(&device_hotplug_lock);
629}
630
631int lock_device_hotplug_sysfs(void)
632{
633 if (mutex_trylock(&device_hotplug_lock))
634 return 0;
635
636 /* Avoid busy looping (5 ms of sleep should do). */
637 msleep(5);
638 return restart_syscall();
639}
640
641#ifdef CONFIG_BLOCK
642static inline int device_is_not_partition(struct device *dev)
643{
644 return !(dev->type == &part_type);
645}
646#else
647static inline int device_is_not_partition(struct device *dev)
648{
649 return 1;
650}
651#endif
652
653/**
654 * dev_driver_string - Return a device's driver name, if at all possible
655 * @dev: struct device to get the name of
656 *
657 * Will return the device's driver's name if it is bound to a device. If
658 * the device is not bound to a driver, it will return the name of the bus
659 * it is attached to. If it is not attached to a bus either, an empty
660 * string will be returned.
661 */
662const char *dev_driver_string(const struct device *dev)
663{
664 struct device_driver *drv;
665
666 /* dev->driver can change to NULL underneath us because of unbinding,
667 * so be careful about accessing it. dev->bus and dev->class should
668 * never change once they are set, so they don't need special care.
669 */
670 drv = ACCESS_ONCE(dev->driver);
671 return drv ? drv->name :
672 (dev->bus ? dev->bus->name :
673 (dev->class ? dev->class->name : ""));
674}
675EXPORT_SYMBOL(dev_driver_string);
676
677#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
678
679static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
680 char *buf)
681{
682 struct device_attribute *dev_attr = to_dev_attr(attr);
683 struct device *dev = kobj_to_dev(kobj);
684 ssize_t ret = -EIO;
685
686 if (dev_attr->show)
687 ret = dev_attr->show(dev, dev_attr, buf);
688 if (ret >= (ssize_t)PAGE_SIZE) {
689 print_symbol("dev_attr_show: %s returned bad count\n",
690 (unsigned long)dev_attr->show);
691 }
692 return ret;
693}
694
695static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
696 const char *buf, size_t count)
697{
698 struct device_attribute *dev_attr = to_dev_attr(attr);
699 struct device *dev = kobj_to_dev(kobj);
700 ssize_t ret = -EIO;
701
702 if (dev_attr->store)
703 ret = dev_attr->store(dev, dev_attr, buf, count);
704 return ret;
705}
706
707static const struct sysfs_ops dev_sysfs_ops = {
708 .show = dev_attr_show,
709 .store = dev_attr_store,
710};
711
712#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
713
714ssize_t device_store_ulong(struct device *dev,
715 struct device_attribute *attr,
716 const char *buf, size_t size)
717{
718 struct dev_ext_attribute *ea = to_ext_attr(attr);
719 char *end;
720 unsigned long new = simple_strtoul(buf, &end, 0);
721 if (end == buf)
722 return -EINVAL;
723 *(unsigned long *)(ea->var) = new;
724 /* Always return full write size even if we didn't consume all */
725 return size;
726}
727EXPORT_SYMBOL_GPL(device_store_ulong);
728
729ssize_t device_show_ulong(struct device *dev,
730 struct device_attribute *attr,
731 char *buf)
732{
733 struct dev_ext_attribute *ea = to_ext_attr(attr);
734 return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
735}
736EXPORT_SYMBOL_GPL(device_show_ulong);
737
738ssize_t device_store_int(struct device *dev,
739 struct device_attribute *attr,
740 const char *buf, size_t size)
741{
742 struct dev_ext_attribute *ea = to_ext_attr(attr);
743 char *end;
744 long new = simple_strtol(buf, &end, 0);
745 if (end == buf || new > INT_MAX || new < INT_MIN)
746 return -EINVAL;
747 *(int *)(ea->var) = new;
748 /* Always return full write size even if we didn't consume all */
749 return size;
750}
751EXPORT_SYMBOL_GPL(device_store_int);
752
753ssize_t device_show_int(struct device *dev,
754 struct device_attribute *attr,
755 char *buf)
756{
757 struct dev_ext_attribute *ea = to_ext_attr(attr);
758
759 return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
760}
761EXPORT_SYMBOL_GPL(device_show_int);
762
763ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
764 const char *buf, size_t size)
765{
766 struct dev_ext_attribute *ea = to_ext_attr(attr);
767
768 if (strtobool(buf, ea->var) < 0)
769 return -EINVAL;
770
771 return size;
772}
773EXPORT_SYMBOL_GPL(device_store_bool);
774
775ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
776 char *buf)
777{
778 struct dev_ext_attribute *ea = to_ext_attr(attr);
779
780 return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
781}
782EXPORT_SYMBOL_GPL(device_show_bool);
783
784/**
785 * device_release - free device structure.
786 * @kobj: device's kobject.
787 *
788 * This is called once the reference count for the object
789 * reaches 0. We forward the call to the device's release
790 * method, which should handle actually freeing the structure.
791 */
792static void device_release(struct kobject *kobj)
793{
794 struct device *dev = kobj_to_dev(kobj);
795 struct device_private *p = dev->p;
796
797 /*
798 * Some platform devices are driven without driver attached
799 * and managed resources may have been acquired. Make sure
800 * all resources are released.
801 *
802 * Drivers still can add resources into device after device
803 * is deleted but alive, so release devres here to avoid
804 * possible memory leak.
805 */
806 devres_release_all(dev);
807
808 if (dev->release)
809 dev->release(dev);
810 else if (dev->type && dev->type->release)
811 dev->type->release(dev);
812 else if (dev->class && dev->class->dev_release)
813 dev->class->dev_release(dev);
814 else
815 WARN(1, KERN_ERR "Device '%s' does not have a release() "
816 "function, it is broken and must be fixed.\n",
817 dev_name(dev));
818 kfree(p);
819}
820
821static const void *device_namespace(struct kobject *kobj)
822{
823 struct device *dev = kobj_to_dev(kobj);
824 const void *ns = NULL;
825
826 if (dev->class && dev->class->ns_type)
827 ns = dev->class->namespace(dev);
828
829 return ns;
830}
831
832static struct kobj_type device_ktype = {
833 .release = device_release,
834 .sysfs_ops = &dev_sysfs_ops,
835 .namespace = device_namespace,
836};
837
838
839static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
840{
841 struct kobj_type *ktype = get_ktype(kobj);
842
843 if (ktype == &device_ktype) {
844 struct device *dev = kobj_to_dev(kobj);
845 if (dev->bus)
846 return 1;
847 if (dev->class)
848 return 1;
849 }
850 return 0;
851}
852
853static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
854{
855 struct device *dev = kobj_to_dev(kobj);
856
857 if (dev->bus)
858 return dev->bus->name;
859 if (dev->class)
860 return dev->class->name;
861 return NULL;
862}
863
864static int dev_uevent(struct kset *kset, struct kobject *kobj,
865 struct kobj_uevent_env *env)
866{
867 struct device *dev = kobj_to_dev(kobj);
868 int retval = 0;
869
870 /* add device node properties if present */
871 if (MAJOR(dev->devt)) {
872 const char *tmp;
873 const char *name;
874 umode_t mode = 0;
875 kuid_t uid = GLOBAL_ROOT_UID;
876 kgid_t gid = GLOBAL_ROOT_GID;
877
878 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
879 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
880 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
881 if (name) {
882 add_uevent_var(env, "DEVNAME=%s", name);
883 if (mode)
884 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
885 if (!uid_eq(uid, GLOBAL_ROOT_UID))
886 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
887 if (!gid_eq(gid, GLOBAL_ROOT_GID))
888 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
889 kfree(tmp);
890 }
891 }
892
893 if (dev->type && dev->type->name)
894 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
895
896 if (dev->driver)
897 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
898
899 /* Add common DT information about the device */
900 of_device_uevent(dev, env);
901
902 /* have the bus specific function add its stuff */
903 if (dev->bus && dev->bus->uevent) {
904 retval = dev->bus->uevent(dev, env);
905 if (retval)
906 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
907 dev_name(dev), __func__, retval);
908 }
909
910 /* have the class specific function add its stuff */
911 if (dev->class && dev->class->dev_uevent) {
912 retval = dev->class->dev_uevent(dev, env);
913 if (retval)
914 pr_debug("device: '%s': %s: class uevent() "
915 "returned %d\n", dev_name(dev),
916 __func__, retval);
917 }
918
919 /* have the device type specific function add its stuff */
920 if (dev->type && dev->type->uevent) {
921 retval = dev->type->uevent(dev, env);
922 if (retval)
923 pr_debug("device: '%s': %s: dev_type uevent() "
924 "returned %d\n", dev_name(dev),
925 __func__, retval);
926 }
927
928 return retval;
929}
930
931static const struct kset_uevent_ops device_uevent_ops = {
932 .filter = dev_uevent_filter,
933 .name = dev_uevent_name,
934 .uevent = dev_uevent,
935};
936
937static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
938 char *buf)
939{
940 struct kobject *top_kobj;
941 struct kset *kset;
942 struct kobj_uevent_env *env = NULL;
943 int i;
944 size_t count = 0;
945 int retval;
946
947 /* search the kset, the device belongs to */
948 top_kobj = &dev->kobj;
949 while (!top_kobj->kset && top_kobj->parent)
950 top_kobj = top_kobj->parent;
951 if (!top_kobj->kset)
952 goto out;
953
954 kset = top_kobj->kset;
955 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
956 goto out;
957
958 /* respect filter */
959 if (kset->uevent_ops && kset->uevent_ops->filter)
960 if (!kset->uevent_ops->filter(kset, &dev->kobj))
961 goto out;
962
963 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
964 if (!env)
965 return -ENOMEM;
966
967 /* let the kset specific function add its keys */
968 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
969 if (retval)
970 goto out;
971
972 /* copy keys to file */
973 for (i = 0; i < env->envp_idx; i++)
974 count += sprintf(&buf[count], "%s\n", env->envp[i]);
975out:
976 kfree(env);
977 return count;
978}
979
980static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
981 const char *buf, size_t count)
982{
983 enum kobject_action action;
984
985 if (kobject_action_type(buf, count, &action) == 0)
986 kobject_uevent(&dev->kobj, action);
987 else
988 dev_err(dev, "uevent: unknown action-string\n");
989 return count;
990}
991static DEVICE_ATTR_RW(uevent);
992
993static ssize_t online_show(struct device *dev, struct device_attribute *attr,
994 char *buf)
995{
996 bool val;
997
998 device_lock(dev);
999 val = !dev->offline;
1000 device_unlock(dev);
1001 return sprintf(buf, "%u\n", val);
1002}
1003
1004static ssize_t online_store(struct device *dev, struct device_attribute *attr,
1005 const char *buf, size_t count)
1006{
1007 bool val;
1008 int ret;
1009
1010 ret = strtobool(buf, &val);
1011 if (ret < 0)
1012 return ret;
1013
1014 ret = lock_device_hotplug_sysfs();
1015 if (ret)
1016 return ret;
1017
1018 ret = val ? device_online(dev) : device_offline(dev);
1019 unlock_device_hotplug();
1020 return ret < 0 ? ret : count;
1021}
1022static DEVICE_ATTR_RW(online);
1023
1024int device_add_groups(struct device *dev, const struct attribute_group **groups)
1025{
1026 return sysfs_create_groups(&dev->kobj, groups);
1027}
1028
1029void device_remove_groups(struct device *dev,
1030 const struct attribute_group **groups)
1031{
1032 sysfs_remove_groups(&dev->kobj, groups);
1033}
1034
1035static int device_add_attrs(struct device *dev)
1036{
1037 struct class *class = dev->class;
1038 const struct device_type *type = dev->type;
1039 int error;
1040
1041 if (class) {
1042 error = device_add_groups(dev, class->dev_groups);
1043 if (error)
1044 return error;
1045 }
1046
1047 if (type) {
1048 error = device_add_groups(dev, type->groups);
1049 if (error)
1050 goto err_remove_class_groups;
1051 }
1052
1053 error = device_add_groups(dev, dev->groups);
1054 if (error)
1055 goto err_remove_type_groups;
1056
1057 if (device_supports_offline(dev) && !dev->offline_disabled) {
1058 error = device_create_file(dev, &dev_attr_online);
1059 if (error)
1060 goto err_remove_dev_groups;
1061 }
1062
1063 return 0;
1064
1065 err_remove_dev_groups:
1066 device_remove_groups(dev, dev->groups);
1067 err_remove_type_groups:
1068 if (type)
1069 device_remove_groups(dev, type->groups);
1070 err_remove_class_groups:
1071 if (class)
1072 device_remove_groups(dev, class->dev_groups);
1073
1074 return error;
1075}
1076
1077static void device_remove_attrs(struct device *dev)
1078{
1079 struct class *class = dev->class;
1080 const struct device_type *type = dev->type;
1081
1082 device_remove_file(dev, &dev_attr_online);
1083 device_remove_groups(dev, dev->groups);
1084
1085 if (type)
1086 device_remove_groups(dev, type->groups);
1087
1088 if (class)
1089 device_remove_groups(dev, class->dev_groups);
1090}
1091
1092static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
1093 char *buf)
1094{
1095 return print_dev_t(buf, dev->devt);
1096}
1097static DEVICE_ATTR_RO(dev);
1098
1099/* /sys/devices/ */
1100struct kset *devices_kset;
1101
1102/**
1103 * devices_kset_move_before - Move device in the devices_kset's list.
1104 * @deva: Device to move.
1105 * @devb: Device @deva should come before.
1106 */
1107static void devices_kset_move_before(struct device *deva, struct device *devb)
1108{
1109 if (!devices_kset)
1110 return;
1111 pr_debug("devices_kset: Moving %s before %s\n",
1112 dev_name(deva), dev_name(devb));
1113 spin_lock(&devices_kset->list_lock);
1114 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
1115 spin_unlock(&devices_kset->list_lock);
1116}
1117
1118/**
1119 * devices_kset_move_after - Move device in the devices_kset's list.
1120 * @deva: Device to move
1121 * @devb: Device @deva should come after.
1122 */
1123static void devices_kset_move_after(struct device *deva, struct device *devb)
1124{
1125 if (!devices_kset)
1126 return;
1127 pr_debug("devices_kset: Moving %s after %s\n",
1128 dev_name(deva), dev_name(devb));
1129 spin_lock(&devices_kset->list_lock);
1130 list_move(&deva->kobj.entry, &devb->kobj.entry);
1131 spin_unlock(&devices_kset->list_lock);
1132}
1133
1134/**
1135 * devices_kset_move_last - move the device to the end of devices_kset's list.
1136 * @dev: device to move
1137 */
1138void devices_kset_move_last(struct device *dev)
1139{
1140 if (!devices_kset)
1141 return;
1142 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
1143 spin_lock(&devices_kset->list_lock);
1144 list_move_tail(&dev->kobj.entry, &devices_kset->list);
1145 spin_unlock(&devices_kset->list_lock);
1146}
1147
1148/**
1149 * device_create_file - create sysfs attribute file for device.
1150 * @dev: device.
1151 * @attr: device attribute descriptor.
1152 */
1153int device_create_file(struct device *dev,
1154 const struct device_attribute *attr)
1155{
1156 int error = 0;
1157
1158 if (dev) {
1159 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
1160 "Attribute %s: write permission without 'store'\n",
1161 attr->attr.name);
1162 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
1163 "Attribute %s: read permission without 'show'\n",
1164 attr->attr.name);
1165 error = sysfs_create_file(&dev->kobj, &attr->attr);
1166 }
1167
1168 return error;
1169}
1170EXPORT_SYMBOL_GPL(device_create_file);
1171
1172/**
1173 * device_remove_file - remove sysfs attribute file.
1174 * @dev: device.
1175 * @attr: device attribute descriptor.
1176 */
1177void device_remove_file(struct device *dev,
1178 const struct device_attribute *attr)
1179{
1180 if (dev)
1181 sysfs_remove_file(&dev->kobj, &attr->attr);
1182}
1183EXPORT_SYMBOL_GPL(device_remove_file);
1184
1185/**
1186 * device_remove_file_self - remove sysfs attribute file from its own method.
1187 * @dev: device.
1188 * @attr: device attribute descriptor.
1189 *
1190 * See kernfs_remove_self() for details.
1191 */
1192bool device_remove_file_self(struct device *dev,
1193 const struct device_attribute *attr)
1194{
1195 if (dev)
1196 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
1197 else
1198 return false;
1199}
1200EXPORT_SYMBOL_GPL(device_remove_file_self);
1201
1202/**
1203 * device_create_bin_file - create sysfs binary attribute file for device.
1204 * @dev: device.
1205 * @attr: device binary attribute descriptor.
1206 */
1207int device_create_bin_file(struct device *dev,
1208 const struct bin_attribute *attr)
1209{
1210 int error = -EINVAL;
1211 if (dev)
1212 error = sysfs_create_bin_file(&dev->kobj, attr);
1213 return error;
1214}
1215EXPORT_SYMBOL_GPL(device_create_bin_file);
1216
1217/**
1218 * device_remove_bin_file - remove sysfs binary attribute file
1219 * @dev: device.
1220 * @attr: device binary attribute descriptor.
1221 */
1222void device_remove_bin_file(struct device *dev,
1223 const struct bin_attribute *attr)
1224{
1225 if (dev)
1226 sysfs_remove_bin_file(&dev->kobj, attr);
1227}
1228EXPORT_SYMBOL_GPL(device_remove_bin_file);
1229
1230static void klist_children_get(struct klist_node *n)
1231{
1232 struct device_private *p = to_device_private_parent(n);
1233 struct device *dev = p->device;
1234
1235 get_device(dev);
1236}
1237
1238static void klist_children_put(struct klist_node *n)
1239{
1240 struct device_private *p = to_device_private_parent(n);
1241 struct device *dev = p->device;
1242
1243 put_device(dev);
1244}
1245
1246/**
1247 * device_initialize - init device structure.
1248 * @dev: device.
1249 *
1250 * This prepares the device for use by other layers by initializing
1251 * its fields.
1252 * It is the first half of device_register(), if called by
1253 * that function, though it can also be called separately, so one
1254 * may use @dev's fields. In particular, get_device()/put_device()
1255 * may be used for reference counting of @dev after calling this
1256 * function.
1257 *
1258 * All fields in @dev must be initialized by the caller to 0, except
1259 * for those explicitly set to some other value. The simplest
1260 * approach is to use kzalloc() to allocate the structure containing
1261 * @dev.
1262 *
1263 * NOTE: Use put_device() to give up your reference instead of freeing
1264 * @dev directly once you have called this function.
1265 */
1266void device_initialize(struct device *dev)
1267{
1268 dev->kobj.kset = devices_kset;
1269 kobject_init(&dev->kobj, &device_ktype);
1270 INIT_LIST_HEAD(&dev->dma_pools);
1271 mutex_init(&dev->mutex);
1272 lockdep_set_novalidate_class(&dev->mutex);
1273 spin_lock_init(&dev->devres_lock);
1274 INIT_LIST_HEAD(&dev->devres_head);
1275 device_pm_init(dev);
1276 set_dev_node(dev, -1);
1277#ifdef CONFIG_GENERIC_MSI_IRQ
1278 INIT_LIST_HEAD(&dev->msi_list);
1279#endif
1280 INIT_LIST_HEAD(&dev->links.consumers);
1281 INIT_LIST_HEAD(&dev->links.suppliers);
1282 dev->links.status = DL_DEV_NO_DRIVER;
1283}
1284EXPORT_SYMBOL_GPL(device_initialize);
1285
1286struct kobject *virtual_device_parent(struct device *dev)
1287{
1288 static struct kobject *virtual_dir = NULL;
1289
1290 if (!virtual_dir)
1291 virtual_dir = kobject_create_and_add("virtual",
1292 &devices_kset->kobj);
1293
1294 return virtual_dir;
1295}
1296
1297struct class_dir {
1298 struct kobject kobj;
1299 struct class *class;
1300};
1301
1302#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
1303
1304static void class_dir_release(struct kobject *kobj)
1305{
1306 struct class_dir *dir = to_class_dir(kobj);
1307 kfree(dir);
1308}
1309
1310static const
1311struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
1312{
1313 struct class_dir *dir = to_class_dir(kobj);
1314 return dir->class->ns_type;
1315}
1316
1317static struct kobj_type class_dir_ktype = {
1318 .release = class_dir_release,
1319 .sysfs_ops = &kobj_sysfs_ops,
1320 .child_ns_type = class_dir_child_ns_type
1321};
1322
1323static struct kobject *
1324class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
1325{
1326 struct class_dir *dir;
1327 int retval;
1328
1329 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1330 if (!dir)
1331 return NULL;
1332
1333 dir->class = class;
1334 kobject_init(&dir->kobj, &class_dir_ktype);
1335
1336 dir->kobj.kset = &class->p->glue_dirs;
1337
1338 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
1339 if (retval < 0) {
1340 kobject_put(&dir->kobj);
1341 return NULL;
1342 }
1343 return &dir->kobj;
1344}
1345
1346static DEFINE_MUTEX(gdp_mutex);
1347
1348static struct kobject *get_device_parent(struct device *dev,
1349 struct device *parent)
1350{
1351 if (dev->class) {
1352 struct kobject *kobj = NULL;
1353 struct kobject *parent_kobj;
1354 struct kobject *k;
1355
1356#ifdef CONFIG_BLOCK
1357 /* block disks show up in /sys/block */
1358 if (sysfs_deprecated && dev->class == &block_class) {
1359 if (parent && parent->class == &block_class)
1360 return &parent->kobj;
1361 return &block_class.p->subsys.kobj;
1362 }
1363#endif
1364
1365 /*
1366 * If we have no parent, we live in "virtual".
1367 * Class-devices with a non class-device as parent, live
1368 * in a "glue" directory to prevent namespace collisions.
1369 */
1370 if (parent == NULL)
1371 parent_kobj = virtual_device_parent(dev);
1372 else if (parent->class && !dev->class->ns_type)
1373 return &parent->kobj;
1374 else
1375 parent_kobj = &parent->kobj;
1376
1377 mutex_lock(&gdp_mutex);
1378
1379 /* find our class-directory at the parent and reference it */
1380 spin_lock(&dev->class->p->glue_dirs.list_lock);
1381 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
1382 if (k->parent == parent_kobj) {
1383 kobj = kobject_get(k);
1384 break;
1385 }
1386 spin_unlock(&dev->class->p->glue_dirs.list_lock);
1387 if (kobj) {
1388 mutex_unlock(&gdp_mutex);
1389 return kobj;
1390 }
1391
1392 /* or create a new class-directory at the parent device */
1393 k = class_dir_create_and_add(dev->class, parent_kobj);
1394 /* do not emit an uevent for this simple "glue" directory */
1395 mutex_unlock(&gdp_mutex);
1396 return k;
1397 }
1398
1399 /* subsystems can specify a default root directory for their devices */
1400 if (!parent && dev->bus && dev->bus->dev_root)
1401 return &dev->bus->dev_root->kobj;
1402
1403 if (parent)
1404 return &parent->kobj;
1405 return NULL;
1406}
1407
1408static inline bool live_in_glue_dir(struct kobject *kobj,
1409 struct device *dev)
1410{
1411 if (!kobj || !dev->class ||
1412 kobj->kset != &dev->class->p->glue_dirs)
1413 return false;
1414 return true;
1415}
1416
1417static inline struct kobject *get_glue_dir(struct device *dev)
1418{
1419 return dev->kobj.parent;
1420}
1421
1422/*
1423 * make sure cleaning up dir as the last step, we need to make
1424 * sure .release handler of kobject is run with holding the
1425 * global lock
1426 */
1427static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
1428{
1429 /* see if we live in a "glue" directory */
1430 if (!live_in_glue_dir(glue_dir, dev))
1431 return;
1432
1433 mutex_lock(&gdp_mutex);
1434 kobject_put(glue_dir);
1435 mutex_unlock(&gdp_mutex);
1436}
1437
1438static int device_add_class_symlinks(struct device *dev)
1439{
1440 struct device_node *of_node = dev_of_node(dev);
1441 int error;
1442
1443 if (of_node) {
1444 error = sysfs_create_link(&dev->kobj, &of_node->kobj,"of_node");
1445 if (error)
1446 dev_warn(dev, "Error %d creating of_node link\n",error);
1447 /* An error here doesn't warrant bringing down the device */
1448 }
1449
1450 if (!dev->class)
1451 return 0;
1452
1453 error = sysfs_create_link(&dev->kobj,
1454 &dev->class->p->subsys.kobj,
1455 "subsystem");
1456 if (error)
1457 goto out_devnode;
1458
1459 if (dev->parent && device_is_not_partition(dev)) {
1460 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
1461 "device");
1462 if (error)
1463 goto out_subsys;
1464 }
1465
1466#ifdef CONFIG_BLOCK
1467 /* /sys/block has directories and does not need symlinks */
1468 if (sysfs_deprecated && dev->class == &block_class)
1469 return 0;
1470#endif
1471
1472 /* link in the class directory pointing to the device */
1473 error = sysfs_create_link(&dev->class->p->subsys.kobj,
1474 &dev->kobj, dev_name(dev));
1475 if (error)
1476 goto out_device;
1477
1478 return 0;
1479
1480out_device:
1481 sysfs_remove_link(&dev->kobj, "device");
1482
1483out_subsys:
1484 sysfs_remove_link(&dev->kobj, "subsystem");
1485out_devnode:
1486 sysfs_remove_link(&dev->kobj, "of_node");
1487 return error;
1488}
1489
1490static void device_remove_class_symlinks(struct device *dev)
1491{
1492 if (dev_of_node(dev))
1493 sysfs_remove_link(&dev->kobj, "of_node");
1494
1495 if (!dev->class)
1496 return;
1497
1498 if (dev->parent && device_is_not_partition(dev))
1499 sysfs_remove_link(&dev->kobj, "device");
1500 sysfs_remove_link(&dev->kobj, "subsystem");
1501#ifdef CONFIG_BLOCK
1502 if (sysfs_deprecated && dev->class == &block_class)
1503 return;
1504#endif
1505 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
1506}
1507
1508/**
1509 * dev_set_name - set a device name
1510 * @dev: device
1511 * @fmt: format string for the device's name
1512 */
1513int dev_set_name(struct device *dev, const char *fmt, ...)
1514{
1515 va_list vargs;
1516 int err;
1517
1518 va_start(vargs, fmt);
1519 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
1520 va_end(vargs);
1521 return err;
1522}
1523EXPORT_SYMBOL_GPL(dev_set_name);
1524
1525/**
1526 * device_to_dev_kobj - select a /sys/dev/ directory for the device
1527 * @dev: device
1528 *
1529 * By default we select char/ for new entries. Setting class->dev_obj
1530 * to NULL prevents an entry from being created. class->dev_kobj must
1531 * be set (or cleared) before any devices are registered to the class
1532 * otherwise device_create_sys_dev_entry() and
1533 * device_remove_sys_dev_entry() will disagree about the presence of
1534 * the link.
1535 */
1536static struct kobject *device_to_dev_kobj(struct device *dev)
1537{
1538 struct kobject *kobj;
1539
1540 if (dev->class)
1541 kobj = dev->class->dev_kobj;
1542 else
1543 kobj = sysfs_dev_char_kobj;
1544
1545 return kobj;
1546}
1547
1548static int device_create_sys_dev_entry(struct device *dev)
1549{
1550 struct kobject *kobj = device_to_dev_kobj(dev);
1551 int error = 0;
1552 char devt_str[15];
1553
1554 if (kobj) {
1555 format_dev_t(devt_str, dev->devt);
1556 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
1557 }
1558
1559 return error;
1560}
1561
1562static void device_remove_sys_dev_entry(struct device *dev)
1563{
1564 struct kobject *kobj = device_to_dev_kobj(dev);
1565 char devt_str[15];
1566
1567 if (kobj) {
1568 format_dev_t(devt_str, dev->devt);
1569 sysfs_remove_link(kobj, devt_str);
1570 }
1571}
1572
1573int device_private_init(struct device *dev)
1574{
1575 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
1576 if (!dev->p)
1577 return -ENOMEM;
1578 dev->p->device = dev;
1579 klist_init(&dev->p->klist_children, klist_children_get,
1580 klist_children_put);
1581 INIT_LIST_HEAD(&dev->p->deferred_probe);
1582 return 0;
1583}
1584
1585/**
1586 * device_add - add device to device hierarchy.
1587 * @dev: device.
1588 *
1589 * This is part 2 of device_register(), though may be called
1590 * separately _iff_ device_initialize() has been called separately.
1591 *
1592 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
1593 * to the global and sibling lists for the device, then
1594 * adds it to the other relevant subsystems of the driver model.
1595 *
1596 * Do not call this routine or device_register() more than once for
1597 * any device structure. The driver model core is not designed to work
1598 * with devices that get unregistered and then spring back to life.
1599 * (Among other things, it's very hard to guarantee that all references
1600 * to the previous incarnation of @dev have been dropped.) Allocate
1601 * and register a fresh new struct device instead.
1602 *
1603 * NOTE: _Never_ directly free @dev after calling this function, even
1604 * if it returned an error! Always use put_device() to give up your
1605 * reference instead.
1606 */
1607int device_add(struct device *dev)
1608{
1609 struct device *parent = NULL;
1610 struct kobject *kobj;
1611 struct class_interface *class_intf;
1612 int error = -EINVAL;
1613 struct kobject *glue_dir = NULL;
1614
1615 dev = get_device(dev);
1616 if (!dev)
1617 goto done;
1618
1619 if (!dev->p) {
1620 error = device_private_init(dev);
1621 if (error)
1622 goto done;
1623 }
1624
1625 /*
1626 * for statically allocated devices, which should all be converted
1627 * some day, we need to initialize the name. We prevent reading back
1628 * the name, and force the use of dev_name()
1629 */
1630 if (dev->init_name) {
1631 dev_set_name(dev, "%s", dev->init_name);
1632 dev->init_name = NULL;
1633 }
1634
1635 /* subsystems can specify simple device enumeration */
1636 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
1637 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
1638
1639 if (!dev_name(dev)) {
1640 error = -EINVAL;
1641 goto name_error;
1642 }
1643
1644 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1645
1646 parent = get_device(dev->parent);
1647 kobj = get_device_parent(dev, parent);
1648 if (kobj)
1649 dev->kobj.parent = kobj;
1650
1651 /* use parent numa_node */
1652 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
1653 set_dev_node(dev, dev_to_node(parent));
1654
1655 /* first, register with generic layer. */
1656 /* we require the name to be set before, and pass NULL */
1657 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
1658 if (error) {
1659 glue_dir = get_glue_dir(dev);
1660 goto Error;
1661 }
1662
1663 /* notify platform of device entry */
1664 if (platform_notify)
1665 platform_notify(dev);
1666
1667 error = device_create_file(dev, &dev_attr_uevent);
1668 if (error)
1669 goto attrError;
1670
1671 error = device_add_class_symlinks(dev);
1672 if (error)
1673 goto SymlinkError;
1674 error = device_add_attrs(dev);
1675 if (error)
1676 goto AttrsError;
1677 error = bus_add_device(dev);
1678 if (error)
1679 goto BusError;
1680 error = dpm_sysfs_add(dev);
1681 if (error)
1682 goto DPMError;
1683 device_pm_add(dev);
1684
1685 if (MAJOR(dev->devt)) {
1686 error = device_create_file(dev, &dev_attr_dev);
1687 if (error)
1688 goto DevAttrError;
1689
1690 error = device_create_sys_dev_entry(dev);
1691 if (error)
1692 goto SysEntryError;
1693
1694 devtmpfs_create_node(dev);
1695 }
1696
1697 /* Notify clients of device addition. This call must come
1698 * after dpm_sysfs_add() and before kobject_uevent().
1699 */
1700 if (dev->bus)
1701 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1702 BUS_NOTIFY_ADD_DEVICE, dev);
1703
1704 kobject_uevent(&dev->kobj, KOBJ_ADD);
1705 bus_probe_device(dev);
1706 if (parent)
1707 klist_add_tail(&dev->p->knode_parent,
1708 &parent->p->klist_children);
1709
1710 if (dev->class) {
1711 mutex_lock(&dev->class->p->mutex);
1712 /* tie the class to the device */
1713 klist_add_tail(&dev->knode_class,
1714 &dev->class->p->klist_devices);
1715
1716 /* notify any interfaces that the device is here */
1717 list_for_each_entry(class_intf,
1718 &dev->class->p->interfaces, node)
1719 if (class_intf->add_dev)
1720 class_intf->add_dev(dev, class_intf);
1721 mutex_unlock(&dev->class->p->mutex);
1722 }
1723done:
1724 put_device(dev);
1725 return error;
1726 SysEntryError:
1727 if (MAJOR(dev->devt))
1728 device_remove_file(dev, &dev_attr_dev);
1729 DevAttrError:
1730 device_pm_remove(dev);
1731 dpm_sysfs_remove(dev);
1732 DPMError:
1733 bus_remove_device(dev);
1734 BusError:
1735 device_remove_attrs(dev);
1736 AttrsError:
1737 device_remove_class_symlinks(dev);
1738 SymlinkError:
1739 device_remove_file(dev, &dev_attr_uevent);
1740 attrError:
1741 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1742 glue_dir = get_glue_dir(dev);
1743 kobject_del(&dev->kobj);
1744 Error:
1745 cleanup_glue_dir(dev, glue_dir);
1746 put_device(parent);
1747name_error:
1748 kfree(dev->p);
1749 dev->p = NULL;
1750 goto done;
1751}
1752EXPORT_SYMBOL_GPL(device_add);
1753
1754/**
1755 * device_register - register a device with the system.
1756 * @dev: pointer to the device structure
1757 *
1758 * This happens in two clean steps - initialize the device
1759 * and add it to the system. The two steps can be called
1760 * separately, but this is the easiest and most common.
1761 * I.e. you should only call the two helpers separately if
1762 * have a clearly defined need to use and refcount the device
1763 * before it is added to the hierarchy.
1764 *
1765 * For more information, see the kerneldoc for device_initialize()
1766 * and device_add().
1767 *
1768 * NOTE: _Never_ directly free @dev after calling this function, even
1769 * if it returned an error! Always use put_device() to give up the
1770 * reference initialized in this function instead.
1771 */
1772int device_register(struct device *dev)
1773{
1774 device_initialize(dev);
1775 return device_add(dev);
1776}
1777EXPORT_SYMBOL_GPL(device_register);
1778
1779/**
1780 * get_device - increment reference count for device.
1781 * @dev: device.
1782 *
1783 * This simply forwards the call to kobject_get(), though
1784 * we do take care to provide for the case that we get a NULL
1785 * pointer passed in.
1786 */
1787struct device *get_device(struct device *dev)
1788{
1789 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
1790}
1791EXPORT_SYMBOL_GPL(get_device);
1792
1793/**
1794 * put_device - decrement reference count.
1795 * @dev: device in question.
1796 */
1797void put_device(struct device *dev)
1798{
1799 /* might_sleep(); */
1800 if (dev)
1801 kobject_put(&dev->kobj);
1802}
1803EXPORT_SYMBOL_GPL(put_device);
1804
1805/**
1806 * device_del - delete device from system.
1807 * @dev: device.
1808 *
1809 * This is the first part of the device unregistration
1810 * sequence. This removes the device from the lists we control
1811 * from here, has it removed from the other driver model
1812 * subsystems it was added to in device_add(), and removes it
1813 * from the kobject hierarchy.
1814 *
1815 * NOTE: this should be called manually _iff_ device_add() was
1816 * also called manually.
1817 */
1818void device_del(struct device *dev)
1819{
1820 struct device *parent = dev->parent;
1821 struct kobject *glue_dir = NULL;
1822 struct class_interface *class_intf;
1823
1824 /* Notify clients of device removal. This call must come
1825 * before dpm_sysfs_remove().
1826 */
1827 if (dev->bus)
1828 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1829 BUS_NOTIFY_DEL_DEVICE, dev);
1830
1831 device_links_purge(dev);
1832 dpm_sysfs_remove(dev);
1833 if (parent)
1834 klist_del(&dev->p->knode_parent);
1835 if (MAJOR(dev->devt)) {
1836 devtmpfs_delete_node(dev);
1837 device_remove_sys_dev_entry(dev);
1838 device_remove_file(dev, &dev_attr_dev);
1839 }
1840 if (dev->class) {
1841 device_remove_class_symlinks(dev);
1842
1843 mutex_lock(&dev->class->p->mutex);
1844 /* notify any interfaces that the device is now gone */
1845 list_for_each_entry(class_intf,
1846 &dev->class->p->interfaces, node)
1847 if (class_intf->remove_dev)
1848 class_intf->remove_dev(dev, class_intf);
1849 /* remove the device from the class list */
1850 klist_del(&dev->knode_class);
1851 mutex_unlock(&dev->class->p->mutex);
1852 }
1853 device_remove_file(dev, &dev_attr_uevent);
1854 device_remove_attrs(dev);
1855 bus_remove_device(dev);
1856 device_pm_remove(dev);
1857 driver_deferred_probe_del(dev);
1858 device_remove_properties(dev);
1859
1860 /* Notify the platform of the removal, in case they
1861 * need to do anything...
1862 */
1863 if (platform_notify_remove)
1864 platform_notify_remove(dev);
1865 if (dev->bus)
1866 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1867 BUS_NOTIFY_REMOVED_DEVICE, dev);
1868 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1869 glue_dir = get_glue_dir(dev);
1870 kobject_del(&dev->kobj);
1871 cleanup_glue_dir(dev, glue_dir);
1872 put_device(parent);
1873}
1874EXPORT_SYMBOL_GPL(device_del);
1875
1876/**
1877 * device_unregister - unregister device from system.
1878 * @dev: device going away.
1879 *
1880 * We do this in two parts, like we do device_register(). First,
1881 * we remove it from all the subsystems with device_del(), then
1882 * we decrement the reference count via put_device(). If that
1883 * is the final reference count, the device will be cleaned up
1884 * via device_release() above. Otherwise, the structure will
1885 * stick around until the final reference to the device is dropped.
1886 */
1887void device_unregister(struct device *dev)
1888{
1889 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1890 device_del(dev);
1891 put_device(dev);
1892}
1893EXPORT_SYMBOL_GPL(device_unregister);
1894
1895static struct device *prev_device(struct klist_iter *i)
1896{
1897 struct klist_node *n = klist_prev(i);
1898 struct device *dev = NULL;
1899 struct device_private *p;
1900
1901 if (n) {
1902 p = to_device_private_parent(n);
1903 dev = p->device;
1904 }
1905 return dev;
1906}
1907
1908static struct device *next_device(struct klist_iter *i)
1909{
1910 struct klist_node *n = klist_next(i);
1911 struct device *dev = NULL;
1912 struct device_private *p;
1913
1914 if (n) {
1915 p = to_device_private_parent(n);
1916 dev = p->device;
1917 }
1918 return dev;
1919}
1920
1921/**
1922 * device_get_devnode - path of device node file
1923 * @dev: device
1924 * @mode: returned file access mode
1925 * @uid: returned file owner
1926 * @gid: returned file group
1927 * @tmp: possibly allocated string
1928 *
1929 * Return the relative path of a possible device node.
1930 * Non-default names may need to allocate a memory to compose
1931 * a name. This memory is returned in tmp and needs to be
1932 * freed by the caller.
1933 */
1934const char *device_get_devnode(struct device *dev,
1935 umode_t *mode, kuid_t *uid, kgid_t *gid,
1936 const char **tmp)
1937{
1938 char *s;
1939
1940 *tmp = NULL;
1941
1942 /* the device type may provide a specific name */
1943 if (dev->type && dev->type->devnode)
1944 *tmp = dev->type->devnode(dev, mode, uid, gid);
1945 if (*tmp)
1946 return *tmp;
1947
1948 /* the class may provide a specific name */
1949 if (dev->class && dev->class->devnode)
1950 *tmp = dev->class->devnode(dev, mode);
1951 if (*tmp)
1952 return *tmp;
1953
1954 /* return name without allocation, tmp == NULL */
1955 if (strchr(dev_name(dev), '!') == NULL)
1956 return dev_name(dev);
1957
1958 /* replace '!' in the name with '/' */
1959 s = kstrdup(dev_name(dev), GFP_KERNEL);
1960 if (!s)
1961 return NULL;
1962 strreplace(s, '!', '/');
1963 return *tmp = s;
1964}
1965
1966/**
1967 * device_for_each_child - device child iterator.
1968 * @parent: parent struct device.
1969 * @fn: function to be called for each device.
1970 * @data: data for the callback.
1971 *
1972 * Iterate over @parent's child devices, and call @fn for each,
1973 * passing it @data.
1974 *
1975 * We check the return of @fn each time. If it returns anything
1976 * other than 0, we break out and return that value.
1977 */
1978int device_for_each_child(struct device *parent, void *data,
1979 int (*fn)(struct device *dev, void *data))
1980{
1981 struct klist_iter i;
1982 struct device *child;
1983 int error = 0;
1984
1985 if (!parent->p)
1986 return 0;
1987
1988 klist_iter_init(&parent->p->klist_children, &i);
1989 while ((child = next_device(&i)) && !error)
1990 error = fn(child, data);
1991 klist_iter_exit(&i);
1992 return error;
1993}
1994EXPORT_SYMBOL_GPL(device_for_each_child);
1995
1996/**
1997 * device_for_each_child_reverse - device child iterator in reversed order.
1998 * @parent: parent struct device.
1999 * @fn: function to be called for each device.
2000 * @data: data for the callback.
2001 *
2002 * Iterate over @parent's child devices, and call @fn for each,
2003 * passing it @data.
2004 *
2005 * We check the return of @fn each time. If it returns anything
2006 * other than 0, we break out and return that value.
2007 */
2008int device_for_each_child_reverse(struct device *parent, void *data,
2009 int (*fn)(struct device *dev, void *data))
2010{
2011 struct klist_iter i;
2012 struct device *child;
2013 int error = 0;
2014
2015 if (!parent->p)
2016 return 0;
2017
2018 klist_iter_init(&parent->p->klist_children, &i);
2019 while ((child = prev_device(&i)) && !error)
2020 error = fn(child, data);
2021 klist_iter_exit(&i);
2022 return error;
2023}
2024EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
2025
2026/**
2027 * device_find_child - device iterator for locating a particular device.
2028 * @parent: parent struct device
2029 * @match: Callback function to check device
2030 * @data: Data to pass to match function
2031 *
2032 * This is similar to the device_for_each_child() function above, but it
2033 * returns a reference to a device that is 'found' for later use, as
2034 * determined by the @match callback.
2035 *
2036 * The callback should return 0 if the device doesn't match and non-zero
2037 * if it does. If the callback returns non-zero and a reference to the
2038 * current device can be obtained, this function will return to the caller
2039 * and not iterate over any more devices.
2040 *
2041 * NOTE: you will need to drop the reference with put_device() after use.
2042 */
2043struct device *device_find_child(struct device *parent, void *data,
2044 int (*match)(struct device *dev, void *data))
2045{
2046 struct klist_iter i;
2047 struct device *child;
2048
2049 if (!parent)
2050 return NULL;
2051
2052 klist_iter_init(&parent->p->klist_children, &i);
2053 while ((child = next_device(&i)))
2054 if (match(child, data) && get_device(child))
2055 break;
2056 klist_iter_exit(&i);
2057 return child;
2058}
2059EXPORT_SYMBOL_GPL(device_find_child);
2060
2061int __init devices_init(void)
2062{
2063 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
2064 if (!devices_kset)
2065 return -ENOMEM;
2066 dev_kobj = kobject_create_and_add("dev", NULL);
2067 if (!dev_kobj)
2068 goto dev_kobj_err;
2069 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
2070 if (!sysfs_dev_block_kobj)
2071 goto block_kobj_err;
2072 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
2073 if (!sysfs_dev_char_kobj)
2074 goto char_kobj_err;
2075
2076 return 0;
2077
2078 char_kobj_err:
2079 kobject_put(sysfs_dev_block_kobj);
2080 block_kobj_err:
2081 kobject_put(dev_kobj);
2082 dev_kobj_err:
2083 kset_unregister(devices_kset);
2084 return -ENOMEM;
2085}
2086
2087static int device_check_offline(struct device *dev, void *not_used)
2088{
2089 int ret;
2090
2091 ret = device_for_each_child(dev, NULL, device_check_offline);
2092 if (ret)
2093 return ret;
2094
2095 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
2096}
2097
2098/**
2099 * device_offline - Prepare the device for hot-removal.
2100 * @dev: Device to be put offline.
2101 *
2102 * Execute the device bus type's .offline() callback, if present, to prepare
2103 * the device for a subsequent hot-removal. If that succeeds, the device must
2104 * not be used until either it is removed or its bus type's .online() callback
2105 * is executed.
2106 *
2107 * Call under device_hotplug_lock.
2108 */
2109int device_offline(struct device *dev)
2110{
2111 int ret;
2112
2113 if (dev->offline_disabled)
2114 return -EPERM;
2115
2116 ret = device_for_each_child(dev, NULL, device_check_offline);
2117 if (ret)
2118 return ret;
2119
2120 device_lock(dev);
2121 if (device_supports_offline(dev)) {
2122 if (dev->offline) {
2123 ret = 1;
2124 } else {
2125 ret = dev->bus->offline(dev);
2126 if (!ret) {
2127 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
2128 dev->offline = true;
2129 }
2130 }
2131 }
2132 device_unlock(dev);
2133
2134 return ret;
2135}
2136
2137/**
2138 * device_online - Put the device back online after successful device_offline().
2139 * @dev: Device to be put back online.
2140 *
2141 * If device_offline() has been successfully executed for @dev, but the device
2142 * has not been removed subsequently, execute its bus type's .online() callback
2143 * to indicate that the device can be used again.
2144 *
2145 * Call under device_hotplug_lock.
2146 */
2147int device_online(struct device *dev)
2148{
2149 int ret = 0;
2150
2151 device_lock(dev);
2152 if (device_supports_offline(dev)) {
2153 if (dev->offline) {
2154 ret = dev->bus->online(dev);
2155 if (!ret) {
2156 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
2157 dev->offline = false;
2158 }
2159 } else {
2160 ret = 1;
2161 }
2162 }
2163 device_unlock(dev);
2164
2165 return ret;
2166}
2167
2168struct root_device {
2169 struct device dev;
2170 struct module *owner;
2171};
2172
2173static inline struct root_device *to_root_device(struct device *d)
2174{
2175 return container_of(d, struct root_device, dev);
2176}
2177
2178static void root_device_release(struct device *dev)
2179{
2180 kfree(to_root_device(dev));
2181}
2182
2183/**
2184 * __root_device_register - allocate and register a root device
2185 * @name: root device name
2186 * @owner: owner module of the root device, usually THIS_MODULE
2187 *
2188 * This function allocates a root device and registers it
2189 * using device_register(). In order to free the returned
2190 * device, use root_device_unregister().
2191 *
2192 * Root devices are dummy devices which allow other devices
2193 * to be grouped under /sys/devices. Use this function to
2194 * allocate a root device and then use it as the parent of
2195 * any device which should appear under /sys/devices/{name}
2196 *
2197 * The /sys/devices/{name} directory will also contain a
2198 * 'module' symlink which points to the @owner directory
2199 * in sysfs.
2200 *
2201 * Returns &struct device pointer on success, or ERR_PTR() on error.
2202 *
2203 * Note: You probably want to use root_device_register().
2204 */
2205struct device *__root_device_register(const char *name, struct module *owner)
2206{
2207 struct root_device *root;
2208 int err = -ENOMEM;
2209
2210 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
2211 if (!root)
2212 return ERR_PTR(err);
2213
2214 err = dev_set_name(&root->dev, "%s", name);
2215 if (err) {
2216 kfree(root);
2217 return ERR_PTR(err);
2218 }
2219
2220 root->dev.release = root_device_release;
2221
2222 err = device_register(&root->dev);
2223 if (err) {
2224 put_device(&root->dev);
2225 return ERR_PTR(err);
2226 }
2227
2228#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
2229 if (owner) {
2230 struct module_kobject *mk = &owner->mkobj;
2231
2232 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
2233 if (err) {
2234 device_unregister(&root->dev);
2235 return ERR_PTR(err);
2236 }
2237 root->owner = owner;
2238 }
2239#endif
2240
2241 return &root->dev;
2242}
2243EXPORT_SYMBOL_GPL(__root_device_register);
2244
2245/**
2246 * root_device_unregister - unregister and free a root device
2247 * @dev: device going away
2248 *
2249 * This function unregisters and cleans up a device that was created by
2250 * root_device_register().
2251 */
2252void root_device_unregister(struct device *dev)
2253{
2254 struct root_device *root = to_root_device(dev);
2255
2256 if (root->owner)
2257 sysfs_remove_link(&root->dev.kobj, "module");
2258
2259 device_unregister(dev);
2260}
2261EXPORT_SYMBOL_GPL(root_device_unregister);
2262
2263
2264static void device_create_release(struct device *dev)
2265{
2266 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
2267 kfree(dev);
2268}
2269
2270static struct device *
2271device_create_groups_vargs(struct class *class, struct device *parent,
2272 dev_t devt, void *drvdata,
2273 const struct attribute_group **groups,
2274 const char *fmt, va_list args)
2275{
2276 struct device *dev = NULL;
2277 int retval = -ENODEV;
2278
2279 if (class == NULL || IS_ERR(class))
2280 goto error;
2281
2282 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2283 if (!dev) {
2284 retval = -ENOMEM;
2285 goto error;
2286 }
2287
2288 device_initialize(dev);
2289 dev->devt = devt;
2290 dev->class = class;
2291 dev->parent = parent;
2292 dev->groups = groups;
2293 dev->release = device_create_release;
2294 dev_set_drvdata(dev, drvdata);
2295
2296 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
2297 if (retval)
2298 goto error;
2299
2300 retval = device_add(dev);
2301 if (retval)
2302 goto error;
2303
2304 return dev;
2305
2306error:
2307 put_device(dev);
2308 return ERR_PTR(retval);
2309}
2310
2311/**
2312 * device_create_vargs - creates a device and registers it with sysfs
2313 * @class: pointer to the struct class that this device should be registered to
2314 * @parent: pointer to the parent struct device of this new device, if any
2315 * @devt: the dev_t for the char device to be added
2316 * @drvdata: the data to be added to the device for callbacks
2317 * @fmt: string for the device's name
2318 * @args: va_list for the device's name
2319 *
2320 * This function can be used by char device classes. A struct device
2321 * will be created in sysfs, registered to the specified class.
2322 *
2323 * A "dev" file will be created, showing the dev_t for the device, if
2324 * the dev_t is not 0,0.
2325 * If a pointer to a parent struct device is passed in, the newly created
2326 * struct device will be a child of that device in sysfs.
2327 * The pointer to the struct device will be returned from the call.
2328 * Any further sysfs files that might be required can be created using this
2329 * pointer.
2330 *
2331 * Returns &struct device pointer on success, or ERR_PTR() on error.
2332 *
2333 * Note: the struct class passed to this function must have previously
2334 * been created with a call to class_create().
2335 */
2336struct device *device_create_vargs(struct class *class, struct device *parent,
2337 dev_t devt, void *drvdata, const char *fmt,
2338 va_list args)
2339{
2340 return device_create_groups_vargs(class, parent, devt, drvdata, NULL,
2341 fmt, args);
2342}
2343EXPORT_SYMBOL_GPL(device_create_vargs);
2344
2345/**
2346 * device_create - creates a device and registers it with sysfs
2347 * @class: pointer to the struct class that this device should be registered to
2348 * @parent: pointer to the parent struct device of this new device, if any
2349 * @devt: the dev_t for the char device to be added
2350 * @drvdata: the data to be added to the device for callbacks
2351 * @fmt: string for the device's name
2352 *
2353 * This function can be used by char device classes. A struct device
2354 * will be created in sysfs, registered to the specified class.
2355 *
2356 * A "dev" file will be created, showing the dev_t for the device, if
2357 * the dev_t is not 0,0.
2358 * If a pointer to a parent struct device is passed in, the newly created
2359 * struct device will be a child of that device in sysfs.
2360 * The pointer to the struct device will be returned from the call.
2361 * Any further sysfs files that might be required can be created using this
2362 * pointer.
2363 *
2364 * Returns &struct device pointer on success, or ERR_PTR() on error.
2365 *
2366 * Note: the struct class passed to this function must have previously
2367 * been created with a call to class_create().
2368 */
2369struct device *device_create(struct class *class, struct device *parent,
2370 dev_t devt, void *drvdata, const char *fmt, ...)
2371{
2372 va_list vargs;
2373 struct device *dev;
2374
2375 va_start(vargs, fmt);
2376 dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
2377 va_end(vargs);
2378 return dev;
2379}
2380EXPORT_SYMBOL_GPL(device_create);
2381
2382/**
2383 * device_create_with_groups - creates a device and registers it with sysfs
2384 * @class: pointer to the struct class that this device should be registered to
2385 * @parent: pointer to the parent struct device of this new device, if any
2386 * @devt: the dev_t for the char device to be added
2387 * @drvdata: the data to be added to the device for callbacks
2388 * @groups: NULL-terminated list of attribute groups to be created
2389 * @fmt: string for the device's name
2390 *
2391 * This function can be used by char device classes. A struct device
2392 * will be created in sysfs, registered to the specified class.
2393 * Additional attributes specified in the groups parameter will also
2394 * be created automatically.
2395 *
2396 * A "dev" file will be created, showing the dev_t for the device, if
2397 * the dev_t is not 0,0.
2398 * If a pointer to a parent struct device is passed in, the newly created
2399 * struct device will be a child of that device in sysfs.
2400 * The pointer to the struct device will be returned from the call.
2401 * Any further sysfs files that might be required can be created using this
2402 * pointer.
2403 *
2404 * Returns &struct device pointer on success, or ERR_PTR() on error.
2405 *
2406 * Note: the struct class passed to this function must have previously
2407 * been created with a call to class_create().
2408 */
2409struct device *device_create_with_groups(struct class *class,
2410 struct device *parent, dev_t devt,
2411 void *drvdata,
2412 const struct attribute_group **groups,
2413 const char *fmt, ...)
2414{
2415 va_list vargs;
2416 struct device *dev;
2417
2418 va_start(vargs, fmt);
2419 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
2420 fmt, vargs);
2421 va_end(vargs);
2422 return dev;
2423}
2424EXPORT_SYMBOL_GPL(device_create_with_groups);
2425
2426static int __match_devt(struct device *dev, const void *data)
2427{
2428 const dev_t *devt = data;
2429
2430 return dev->devt == *devt;
2431}
2432
2433/**
2434 * device_destroy - removes a device that was created with device_create()
2435 * @class: pointer to the struct class that this device was registered with
2436 * @devt: the dev_t of the device that was previously registered
2437 *
2438 * This call unregisters and cleans up a device that was created with a
2439 * call to device_create().
2440 */
2441void device_destroy(struct class *class, dev_t devt)
2442{
2443 struct device *dev;
2444
2445 dev = class_find_device(class, NULL, &devt, __match_devt);
2446 if (dev) {
2447 put_device(dev);
2448 device_unregister(dev);
2449 }
2450}
2451EXPORT_SYMBOL_GPL(device_destroy);
2452
2453/**
2454 * device_rename - renames a device
2455 * @dev: the pointer to the struct device to be renamed
2456 * @new_name: the new name of the device
2457 *
2458 * It is the responsibility of the caller to provide mutual
2459 * exclusion between two different calls of device_rename
2460 * on the same device to ensure that new_name is valid and
2461 * won't conflict with other devices.
2462 *
2463 * Note: Don't call this function. Currently, the networking layer calls this
2464 * function, but that will change. The following text from Kay Sievers offers
2465 * some insight:
2466 *
2467 * Renaming devices is racy at many levels, symlinks and other stuff are not
2468 * replaced atomically, and you get a "move" uevent, but it's not easy to
2469 * connect the event to the old and new device. Device nodes are not renamed at
2470 * all, there isn't even support for that in the kernel now.
2471 *
2472 * In the meantime, during renaming, your target name might be taken by another
2473 * driver, creating conflicts. Or the old name is taken directly after you
2474 * renamed it -- then you get events for the same DEVPATH, before you even see
2475 * the "move" event. It's just a mess, and nothing new should ever rely on
2476 * kernel device renaming. Besides that, it's not even implemented now for
2477 * other things than (driver-core wise very simple) network devices.
2478 *
2479 * We are currently about to change network renaming in udev to completely
2480 * disallow renaming of devices in the same namespace as the kernel uses,
2481 * because we can't solve the problems properly, that arise with swapping names
2482 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
2483 * be allowed to some other name than eth[0-9]*, for the aforementioned
2484 * reasons.
2485 *
2486 * Make up a "real" name in the driver before you register anything, or add
2487 * some other attributes for userspace to find the device, or use udev to add
2488 * symlinks -- but never rename kernel devices later, it's a complete mess. We
2489 * don't even want to get into that and try to implement the missing pieces in
2490 * the core. We really have other pieces to fix in the driver core mess. :)
2491 */
2492int device_rename(struct device *dev, const char *new_name)
2493{
2494 struct kobject *kobj = &dev->kobj;
2495 char *old_device_name = NULL;
2496 int error;
2497
2498 dev = get_device(dev);
2499 if (!dev)
2500 return -EINVAL;
2501
2502 dev_dbg(dev, "renaming to %s\n", new_name);
2503
2504 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
2505 if (!old_device_name) {
2506 error = -ENOMEM;
2507 goto out;
2508 }
2509
2510 if (dev->class) {
2511 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
2512 kobj, old_device_name,
2513 new_name, kobject_namespace(kobj));
2514 if (error)
2515 goto out;
2516 }
2517
2518 error = kobject_rename(kobj, new_name);
2519 if (error)
2520 goto out;
2521
2522out:
2523 put_device(dev);
2524
2525 kfree(old_device_name);
2526
2527 return error;
2528}
2529EXPORT_SYMBOL_GPL(device_rename);
2530
2531static int device_move_class_links(struct device *dev,
2532 struct device *old_parent,
2533 struct device *new_parent)
2534{
2535 int error = 0;
2536
2537 if (old_parent)
2538 sysfs_remove_link(&dev->kobj, "device");
2539 if (new_parent)
2540 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
2541 "device");
2542 return error;
2543}
2544
2545/**
2546 * device_move - moves a device to a new parent
2547 * @dev: the pointer to the struct device to be moved
2548 * @new_parent: the new parent of the device (can by NULL)
2549 * @dpm_order: how to reorder the dpm_list
2550 */
2551int device_move(struct device *dev, struct device *new_parent,
2552 enum dpm_order dpm_order)
2553{
2554 int error;
2555 struct device *old_parent;
2556 struct kobject *new_parent_kobj;
2557
2558 dev = get_device(dev);
2559 if (!dev)
2560 return -EINVAL;
2561
2562 device_pm_lock();
2563 new_parent = get_device(new_parent);
2564 new_parent_kobj = get_device_parent(dev, new_parent);
2565
2566 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
2567 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
2568 error = kobject_move(&dev->kobj, new_parent_kobj);
2569 if (error) {
2570 cleanup_glue_dir(dev, new_parent_kobj);
2571 put_device(new_parent);
2572 goto out;
2573 }
2574 old_parent = dev->parent;
2575 dev->parent = new_parent;
2576 if (old_parent)
2577 klist_remove(&dev->p->knode_parent);
2578 if (new_parent) {
2579 klist_add_tail(&dev->p->knode_parent,
2580 &new_parent->p->klist_children);
2581 set_dev_node(dev, dev_to_node(new_parent));
2582 }
2583
2584 if (dev->class) {
2585 error = device_move_class_links(dev, old_parent, new_parent);
2586 if (error) {
2587 /* We ignore errors on cleanup since we're hosed anyway... */
2588 device_move_class_links(dev, new_parent, old_parent);
2589 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
2590 if (new_parent)
2591 klist_remove(&dev->p->knode_parent);
2592 dev->parent = old_parent;
2593 if (old_parent) {
2594 klist_add_tail(&dev->p->knode_parent,
2595 &old_parent->p->klist_children);
2596 set_dev_node(dev, dev_to_node(old_parent));
2597 }
2598 }
2599 cleanup_glue_dir(dev, new_parent_kobj);
2600 put_device(new_parent);
2601 goto out;
2602 }
2603 }
2604 switch (dpm_order) {
2605 case DPM_ORDER_NONE:
2606 break;
2607 case DPM_ORDER_DEV_AFTER_PARENT:
2608 device_pm_move_after(dev, new_parent);
2609 devices_kset_move_after(dev, new_parent);
2610 break;
2611 case DPM_ORDER_PARENT_BEFORE_DEV:
2612 device_pm_move_before(new_parent, dev);
2613 devices_kset_move_before(new_parent, dev);
2614 break;
2615 case DPM_ORDER_DEV_LAST:
2616 device_pm_move_last(dev);
2617 devices_kset_move_last(dev);
2618 break;
2619 }
2620
2621 put_device(old_parent);
2622out:
2623 device_pm_unlock();
2624 put_device(dev);
2625 return error;
2626}
2627EXPORT_SYMBOL_GPL(device_move);
2628
2629/**
2630 * device_shutdown - call ->shutdown() on each device to shutdown.
2631 */
2632void device_shutdown(void)
2633{
2634 struct device *dev, *parent;
2635
2636 spin_lock(&devices_kset->list_lock);
2637 /*
2638 * Walk the devices list backward, shutting down each in turn.
2639 * Beware that device unplug events may also start pulling
2640 * devices offline, even as the system is shutting down.
2641 */
2642 while (!list_empty(&devices_kset->list)) {
2643 dev = list_entry(devices_kset->list.prev, struct device,
2644 kobj.entry);
2645
2646 /*
2647 * hold reference count of device's parent to
2648 * prevent it from being freed because parent's
2649 * lock is to be held
2650 */
2651 parent = get_device(dev->parent);
2652 get_device(dev);
2653 /*
2654 * Make sure the device is off the kset list, in the
2655 * event that dev->*->shutdown() doesn't remove it.
2656 */
2657 list_del_init(&dev->kobj.entry);
2658 spin_unlock(&devices_kset->list_lock);
2659
2660 /* hold lock to avoid race with probe/release */
2661 if (parent)
2662 device_lock(parent);
2663 device_lock(dev);
2664
2665 /* Don't allow any more runtime suspends */
2666 pm_runtime_get_noresume(dev);
2667 pm_runtime_barrier(dev);
2668
2669 if (dev->bus && dev->bus->shutdown) {
2670 if (initcall_debug)
2671 dev_info(dev, "shutdown\n");
2672 dev->bus->shutdown(dev);
2673 } else if (dev->driver && dev->driver->shutdown) {
2674 if (initcall_debug)
2675 dev_info(dev, "shutdown\n");
2676 dev->driver->shutdown(dev);
2677 }
2678
2679 device_unlock(dev);
2680 if (parent)
2681 device_unlock(parent);
2682
2683 put_device(dev);
2684 put_device(parent);
2685
2686 spin_lock(&devices_kset->list_lock);
2687 }
2688 spin_unlock(&devices_kset->list_lock);
2689}
2690
2691/*
2692 * Device logging functions
2693 */
2694
2695#ifdef CONFIG_PRINTK
2696static int
2697create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
2698{
2699 const char *subsys;
2700 size_t pos = 0;
2701
2702 if (dev->class)
2703 subsys = dev->class->name;
2704 else if (dev->bus)
2705 subsys = dev->bus->name;
2706 else
2707 return 0;
2708
2709 pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
2710 if (pos >= hdrlen)
2711 goto overflow;
2712
2713 /*
2714 * Add device identifier DEVICE=:
2715 * b12:8 block dev_t
2716 * c127:3 char dev_t
2717 * n8 netdev ifindex
2718 * +sound:card0 subsystem:devname
2719 */
2720 if (MAJOR(dev->devt)) {
2721 char c;
2722
2723 if (strcmp(subsys, "block") == 0)
2724 c = 'b';
2725 else
2726 c = 'c';
2727 pos++;
2728 pos += snprintf(hdr + pos, hdrlen - pos,
2729 "DEVICE=%c%u:%u",
2730 c, MAJOR(dev->devt), MINOR(dev->devt));
2731 } else if (strcmp(subsys, "net") == 0) {
2732 struct net_device *net = to_net_dev(dev);
2733
2734 pos++;
2735 pos += snprintf(hdr + pos, hdrlen - pos,
2736 "DEVICE=n%u", net->ifindex);
2737 } else {
2738 pos++;
2739 pos += snprintf(hdr + pos, hdrlen - pos,
2740 "DEVICE=+%s:%s", subsys, dev_name(dev));
2741 }
2742
2743 if (pos >= hdrlen)
2744 goto overflow;
2745
2746 return pos;
2747
2748overflow:
2749 dev_WARN(dev, "device/subsystem name too long");
2750 return 0;
2751}
2752
2753int dev_vprintk_emit(int level, const struct device *dev,
2754 const char *fmt, va_list args)
2755{
2756 char hdr[128];
2757 size_t hdrlen;
2758
2759 hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
2760
2761 return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
2762}
2763EXPORT_SYMBOL(dev_vprintk_emit);
2764
2765int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
2766{
2767 va_list args;
2768 int r;
2769
2770 va_start(args, fmt);
2771
2772 r = dev_vprintk_emit(level, dev, fmt, args);
2773
2774 va_end(args);
2775
2776 return r;
2777}
2778EXPORT_SYMBOL(dev_printk_emit);
2779
2780static void __dev_printk(const char *level, const struct device *dev,
2781 struct va_format *vaf)
2782{
2783 if (dev)
2784 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
2785 dev_driver_string(dev), dev_name(dev), vaf);
2786 else
2787 printk("%s(NULL device *): %pV", level, vaf);
2788}
2789
2790void dev_printk(const char *level, const struct device *dev,
2791 const char *fmt, ...)
2792{
2793 struct va_format vaf;
2794 va_list args;
2795
2796 va_start(args, fmt);
2797
2798 vaf.fmt = fmt;
2799 vaf.va = &args;
2800
2801 __dev_printk(level, dev, &vaf);
2802
2803 va_end(args);
2804}
2805EXPORT_SYMBOL(dev_printk);
2806
2807#define define_dev_printk_level(func, kern_level) \
2808void func(const struct device *dev, const char *fmt, ...) \
2809{ \
2810 struct va_format vaf; \
2811 va_list args; \
2812 \
2813 va_start(args, fmt); \
2814 \
2815 vaf.fmt = fmt; \
2816 vaf.va = &args; \
2817 \
2818 __dev_printk(kern_level, dev, &vaf); \
2819 \
2820 va_end(args); \
2821} \
2822EXPORT_SYMBOL(func);
2823
2824define_dev_printk_level(dev_emerg, KERN_EMERG);
2825define_dev_printk_level(dev_alert, KERN_ALERT);
2826define_dev_printk_level(dev_crit, KERN_CRIT);
2827define_dev_printk_level(dev_err, KERN_ERR);
2828define_dev_printk_level(dev_warn, KERN_WARNING);
2829define_dev_printk_level(dev_notice, KERN_NOTICE);
2830define_dev_printk_level(_dev_info, KERN_INFO);
2831
2832#endif
2833
2834static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
2835{
2836 return fwnode && !IS_ERR(fwnode->secondary);
2837}
2838
2839/**
2840 * set_primary_fwnode - Change the primary firmware node of a given device.
2841 * @dev: Device to handle.
2842 * @fwnode: New primary firmware node of the device.
2843 *
2844 * Set the device's firmware node pointer to @fwnode, but if a secondary
2845 * firmware node of the device is present, preserve it.
2846 */
2847void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
2848{
2849 if (fwnode) {
2850 struct fwnode_handle *fn = dev->fwnode;
2851
2852 if (fwnode_is_primary(fn))
2853 fn = fn->secondary;
2854
2855 if (fn) {
2856 WARN_ON(fwnode->secondary);
2857 fwnode->secondary = fn;
2858 }
2859 dev->fwnode = fwnode;
2860 } else {
2861 dev->fwnode = fwnode_is_primary(dev->fwnode) ?
2862 dev->fwnode->secondary : NULL;
2863 }
2864}
2865EXPORT_SYMBOL_GPL(set_primary_fwnode);
2866
2867/**
2868 * set_secondary_fwnode - Change the secondary firmware node of a given device.
2869 * @dev: Device to handle.
2870 * @fwnode: New secondary firmware node of the device.
2871 *
2872 * If a primary firmware node of the device is present, set its secondary
2873 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
2874 * @fwnode.
2875 */
2876void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
2877{
2878 if (fwnode)
2879 fwnode->secondary = ERR_PTR(-ENODEV);
2880
2881 if (fwnode_is_primary(dev->fwnode))
2882 dev->fwnode->secondary = fwnode;
2883 else
2884 dev->fwnode = fwnode;
2885}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/core.c - core driver model code (device registration, etc)
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (c) 2006 Novell, Inc.
9 */
10
11#include <linux/acpi.h>
12#include <linux/cpufreq.h>
13#include <linux/device.h>
14#include <linux/err.h>
15#include <linux/fwnode.h>
16#include <linux/init.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19#include <linux/string.h>
20#include <linux/kdev_t.h>
21#include <linux/notifier.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/genhd.h>
25#include <linux/mutex.h>
26#include <linux/pm_runtime.h>
27#include <linux/netdevice.h>
28#include <linux/sched/signal.h>
29#include <linux/sched/mm.h>
30#include <linux/sysfs.h>
31#include <linux/dma-map-ops.h> /* for dma_default_coherent */
32
33#include "base.h"
34#include "power/power.h"
35
36#ifdef CONFIG_SYSFS_DEPRECATED
37#ifdef CONFIG_SYSFS_DEPRECATED_V2
38long sysfs_deprecated = 1;
39#else
40long sysfs_deprecated = 0;
41#endif
42static int __init sysfs_deprecated_setup(char *arg)
43{
44 return kstrtol(arg, 10, &sysfs_deprecated);
45}
46early_param("sysfs.deprecated", sysfs_deprecated_setup);
47#endif
48
49/* Device links support. */
50static LIST_HEAD(deferred_sync);
51static unsigned int defer_sync_state_count = 1;
52static DEFINE_MUTEX(fwnode_link_lock);
53static bool fw_devlink_is_permissive(void);
54static bool fw_devlink_drv_reg_done;
55
56/**
57 * fwnode_link_add - Create a link between two fwnode_handles.
58 * @con: Consumer end of the link.
59 * @sup: Supplier end of the link.
60 *
61 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
62 * represents the detail that the firmware lists @sup fwnode as supplying a
63 * resource to @con.
64 *
65 * The driver core will use the fwnode link to create a device link between the
66 * two device objects corresponding to @con and @sup when they are created. The
67 * driver core will automatically delete the fwnode link between @con and @sup
68 * after doing that.
69 *
70 * Attempts to create duplicate links between the same pair of fwnode handles
71 * are ignored and there is no reference counting.
72 */
73int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
74{
75 struct fwnode_link *link;
76 int ret = 0;
77
78 mutex_lock(&fwnode_link_lock);
79
80 list_for_each_entry(link, &sup->consumers, s_hook)
81 if (link->consumer == con)
82 goto out;
83
84 link = kzalloc(sizeof(*link), GFP_KERNEL);
85 if (!link) {
86 ret = -ENOMEM;
87 goto out;
88 }
89
90 link->supplier = sup;
91 INIT_LIST_HEAD(&link->s_hook);
92 link->consumer = con;
93 INIT_LIST_HEAD(&link->c_hook);
94
95 list_add(&link->s_hook, &sup->consumers);
96 list_add(&link->c_hook, &con->suppliers);
97out:
98 mutex_unlock(&fwnode_link_lock);
99
100 return ret;
101}
102
103/**
104 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
105 * @fwnode: fwnode whose supplier links need to be deleted
106 *
107 * Deletes all supplier links connecting directly to @fwnode.
108 */
109static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
110{
111 struct fwnode_link *link, *tmp;
112
113 mutex_lock(&fwnode_link_lock);
114 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
115 list_del(&link->s_hook);
116 list_del(&link->c_hook);
117 kfree(link);
118 }
119 mutex_unlock(&fwnode_link_lock);
120}
121
122/**
123 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
124 * @fwnode: fwnode whose consumer links need to be deleted
125 *
126 * Deletes all consumer links connecting directly to @fwnode.
127 */
128static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
129{
130 struct fwnode_link *link, *tmp;
131
132 mutex_lock(&fwnode_link_lock);
133 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
134 list_del(&link->s_hook);
135 list_del(&link->c_hook);
136 kfree(link);
137 }
138 mutex_unlock(&fwnode_link_lock);
139}
140
141/**
142 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
143 * @fwnode: fwnode whose links needs to be deleted
144 *
145 * Deletes all links connecting directly to a fwnode.
146 */
147void fwnode_links_purge(struct fwnode_handle *fwnode)
148{
149 fwnode_links_purge_suppliers(fwnode);
150 fwnode_links_purge_consumers(fwnode);
151}
152
153void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
154{
155 struct fwnode_handle *child;
156
157 /* Don't purge consumer links of an added child */
158 if (fwnode->dev)
159 return;
160
161 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
162 fwnode_links_purge_consumers(fwnode);
163
164 fwnode_for_each_available_child_node(fwnode, child)
165 fw_devlink_purge_absent_suppliers(child);
166}
167EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
168
169#ifdef CONFIG_SRCU
170static DEFINE_MUTEX(device_links_lock);
171DEFINE_STATIC_SRCU(device_links_srcu);
172
173static inline void device_links_write_lock(void)
174{
175 mutex_lock(&device_links_lock);
176}
177
178static inline void device_links_write_unlock(void)
179{
180 mutex_unlock(&device_links_lock);
181}
182
183int device_links_read_lock(void) __acquires(&device_links_srcu)
184{
185 return srcu_read_lock(&device_links_srcu);
186}
187
188void device_links_read_unlock(int idx) __releases(&device_links_srcu)
189{
190 srcu_read_unlock(&device_links_srcu, idx);
191}
192
193int device_links_read_lock_held(void)
194{
195 return srcu_read_lock_held(&device_links_srcu);
196}
197
198static void device_link_synchronize_removal(void)
199{
200 synchronize_srcu(&device_links_srcu);
201}
202
203static void device_link_remove_from_lists(struct device_link *link)
204{
205 list_del_rcu(&link->s_node);
206 list_del_rcu(&link->c_node);
207}
208#else /* !CONFIG_SRCU */
209static DECLARE_RWSEM(device_links_lock);
210
211static inline void device_links_write_lock(void)
212{
213 down_write(&device_links_lock);
214}
215
216static inline void device_links_write_unlock(void)
217{
218 up_write(&device_links_lock);
219}
220
221int device_links_read_lock(void)
222{
223 down_read(&device_links_lock);
224 return 0;
225}
226
227void device_links_read_unlock(int not_used)
228{
229 up_read(&device_links_lock);
230}
231
232#ifdef CONFIG_DEBUG_LOCK_ALLOC
233int device_links_read_lock_held(void)
234{
235 return lockdep_is_held(&device_links_lock);
236}
237#endif
238
239static inline void device_link_synchronize_removal(void)
240{
241}
242
243static void device_link_remove_from_lists(struct device_link *link)
244{
245 list_del(&link->s_node);
246 list_del(&link->c_node);
247}
248#endif /* !CONFIG_SRCU */
249
250static bool device_is_ancestor(struct device *dev, struct device *target)
251{
252 while (target->parent) {
253 target = target->parent;
254 if (dev == target)
255 return true;
256 }
257 return false;
258}
259
260/**
261 * device_is_dependent - Check if one device depends on another one
262 * @dev: Device to check dependencies for.
263 * @target: Device to check against.
264 *
265 * Check if @target depends on @dev or any device dependent on it (its child or
266 * its consumer etc). Return 1 if that is the case or 0 otherwise.
267 */
268int device_is_dependent(struct device *dev, void *target)
269{
270 struct device_link *link;
271 int ret;
272
273 /*
274 * The "ancestors" check is needed to catch the case when the target
275 * device has not been completely initialized yet and it is still
276 * missing from the list of children of its parent device.
277 */
278 if (dev == target || device_is_ancestor(dev, target))
279 return 1;
280
281 ret = device_for_each_child(dev, target, device_is_dependent);
282 if (ret)
283 return ret;
284
285 list_for_each_entry(link, &dev->links.consumers, s_node) {
286 if ((link->flags & ~DL_FLAG_INFERRED) ==
287 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
288 continue;
289
290 if (link->consumer == target)
291 return 1;
292
293 ret = device_is_dependent(link->consumer, target);
294 if (ret)
295 break;
296 }
297 return ret;
298}
299
300static void device_link_init_status(struct device_link *link,
301 struct device *consumer,
302 struct device *supplier)
303{
304 switch (supplier->links.status) {
305 case DL_DEV_PROBING:
306 switch (consumer->links.status) {
307 case DL_DEV_PROBING:
308 /*
309 * A consumer driver can create a link to a supplier
310 * that has not completed its probing yet as long as it
311 * knows that the supplier is already functional (for
312 * example, it has just acquired some resources from the
313 * supplier).
314 */
315 link->status = DL_STATE_CONSUMER_PROBE;
316 break;
317 default:
318 link->status = DL_STATE_DORMANT;
319 break;
320 }
321 break;
322 case DL_DEV_DRIVER_BOUND:
323 switch (consumer->links.status) {
324 case DL_DEV_PROBING:
325 link->status = DL_STATE_CONSUMER_PROBE;
326 break;
327 case DL_DEV_DRIVER_BOUND:
328 link->status = DL_STATE_ACTIVE;
329 break;
330 default:
331 link->status = DL_STATE_AVAILABLE;
332 break;
333 }
334 break;
335 case DL_DEV_UNBINDING:
336 link->status = DL_STATE_SUPPLIER_UNBIND;
337 break;
338 default:
339 link->status = DL_STATE_DORMANT;
340 break;
341 }
342}
343
344static int device_reorder_to_tail(struct device *dev, void *not_used)
345{
346 struct device_link *link;
347
348 /*
349 * Devices that have not been registered yet will be put to the ends
350 * of the lists during the registration, so skip them here.
351 */
352 if (device_is_registered(dev))
353 devices_kset_move_last(dev);
354
355 if (device_pm_initialized(dev))
356 device_pm_move_last(dev);
357
358 device_for_each_child(dev, NULL, device_reorder_to_tail);
359 list_for_each_entry(link, &dev->links.consumers, s_node) {
360 if ((link->flags & ~DL_FLAG_INFERRED) ==
361 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
362 continue;
363 device_reorder_to_tail(link->consumer, NULL);
364 }
365
366 return 0;
367}
368
369/**
370 * device_pm_move_to_tail - Move set of devices to the end of device lists
371 * @dev: Device to move
372 *
373 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
374 *
375 * It moves the @dev along with all of its children and all of its consumers
376 * to the ends of the device_kset and dpm_list, recursively.
377 */
378void device_pm_move_to_tail(struct device *dev)
379{
380 int idx;
381
382 idx = device_links_read_lock();
383 device_pm_lock();
384 device_reorder_to_tail(dev, NULL);
385 device_pm_unlock();
386 device_links_read_unlock(idx);
387}
388
389#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
390
391static ssize_t status_show(struct device *dev,
392 struct device_attribute *attr, char *buf)
393{
394 const char *output;
395
396 switch (to_devlink(dev)->status) {
397 case DL_STATE_NONE:
398 output = "not tracked";
399 break;
400 case DL_STATE_DORMANT:
401 output = "dormant";
402 break;
403 case DL_STATE_AVAILABLE:
404 output = "available";
405 break;
406 case DL_STATE_CONSUMER_PROBE:
407 output = "consumer probing";
408 break;
409 case DL_STATE_ACTIVE:
410 output = "active";
411 break;
412 case DL_STATE_SUPPLIER_UNBIND:
413 output = "supplier unbinding";
414 break;
415 default:
416 output = "unknown";
417 break;
418 }
419
420 return sysfs_emit(buf, "%s\n", output);
421}
422static DEVICE_ATTR_RO(status);
423
424static ssize_t auto_remove_on_show(struct device *dev,
425 struct device_attribute *attr, char *buf)
426{
427 struct device_link *link = to_devlink(dev);
428 const char *output;
429
430 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
431 output = "supplier unbind";
432 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
433 output = "consumer unbind";
434 else
435 output = "never";
436
437 return sysfs_emit(buf, "%s\n", output);
438}
439static DEVICE_ATTR_RO(auto_remove_on);
440
441static ssize_t runtime_pm_show(struct device *dev,
442 struct device_attribute *attr, char *buf)
443{
444 struct device_link *link = to_devlink(dev);
445
446 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
447}
448static DEVICE_ATTR_RO(runtime_pm);
449
450static ssize_t sync_state_only_show(struct device *dev,
451 struct device_attribute *attr, char *buf)
452{
453 struct device_link *link = to_devlink(dev);
454
455 return sysfs_emit(buf, "%d\n",
456 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
457}
458static DEVICE_ATTR_RO(sync_state_only);
459
460static struct attribute *devlink_attrs[] = {
461 &dev_attr_status.attr,
462 &dev_attr_auto_remove_on.attr,
463 &dev_attr_runtime_pm.attr,
464 &dev_attr_sync_state_only.attr,
465 NULL,
466};
467ATTRIBUTE_GROUPS(devlink);
468
469static void device_link_release_fn(struct work_struct *work)
470{
471 struct device_link *link = container_of(work, struct device_link, rm_work);
472
473 /* Ensure that all references to the link object have been dropped. */
474 device_link_synchronize_removal();
475
476 while (refcount_dec_not_one(&link->rpm_active))
477 pm_runtime_put(link->supplier);
478
479 put_device(link->consumer);
480 put_device(link->supplier);
481 kfree(link);
482}
483
484static void devlink_dev_release(struct device *dev)
485{
486 struct device_link *link = to_devlink(dev);
487
488 INIT_WORK(&link->rm_work, device_link_release_fn);
489 /*
490 * It may take a while to complete this work because of the SRCU
491 * synchronization in device_link_release_fn() and if the consumer or
492 * supplier devices get deleted when it runs, so put it into the "long"
493 * workqueue.
494 */
495 queue_work(system_long_wq, &link->rm_work);
496}
497
498static struct class devlink_class = {
499 .name = "devlink",
500 .owner = THIS_MODULE,
501 .dev_groups = devlink_groups,
502 .dev_release = devlink_dev_release,
503};
504
505static int devlink_add_symlinks(struct device *dev,
506 struct class_interface *class_intf)
507{
508 int ret;
509 size_t len;
510 struct device_link *link = to_devlink(dev);
511 struct device *sup = link->supplier;
512 struct device *con = link->consumer;
513 char *buf;
514
515 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
516 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
517 len += strlen(":");
518 len += strlen("supplier:") + 1;
519 buf = kzalloc(len, GFP_KERNEL);
520 if (!buf)
521 return -ENOMEM;
522
523 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
524 if (ret)
525 goto out;
526
527 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
528 if (ret)
529 goto err_con;
530
531 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
532 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
533 if (ret)
534 goto err_con_dev;
535
536 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
537 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
538 if (ret)
539 goto err_sup_dev;
540
541 goto out;
542
543err_sup_dev:
544 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
545 sysfs_remove_link(&sup->kobj, buf);
546err_con_dev:
547 sysfs_remove_link(&link->link_dev.kobj, "consumer");
548err_con:
549 sysfs_remove_link(&link->link_dev.kobj, "supplier");
550out:
551 kfree(buf);
552 return ret;
553}
554
555static void devlink_remove_symlinks(struct device *dev,
556 struct class_interface *class_intf)
557{
558 struct device_link *link = to_devlink(dev);
559 size_t len;
560 struct device *sup = link->supplier;
561 struct device *con = link->consumer;
562 char *buf;
563
564 sysfs_remove_link(&link->link_dev.kobj, "consumer");
565 sysfs_remove_link(&link->link_dev.kobj, "supplier");
566
567 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
568 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
569 len += strlen(":");
570 len += strlen("supplier:") + 1;
571 buf = kzalloc(len, GFP_KERNEL);
572 if (!buf) {
573 WARN(1, "Unable to properly free device link symlinks!\n");
574 return;
575 }
576
577 if (device_is_registered(con)) {
578 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
579 sysfs_remove_link(&con->kobj, buf);
580 }
581 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
582 sysfs_remove_link(&sup->kobj, buf);
583 kfree(buf);
584}
585
586static struct class_interface devlink_class_intf = {
587 .class = &devlink_class,
588 .add_dev = devlink_add_symlinks,
589 .remove_dev = devlink_remove_symlinks,
590};
591
592static int __init devlink_class_init(void)
593{
594 int ret;
595
596 ret = class_register(&devlink_class);
597 if (ret)
598 return ret;
599
600 ret = class_interface_register(&devlink_class_intf);
601 if (ret)
602 class_unregister(&devlink_class);
603
604 return ret;
605}
606postcore_initcall(devlink_class_init);
607
608#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
609 DL_FLAG_AUTOREMOVE_SUPPLIER | \
610 DL_FLAG_AUTOPROBE_CONSUMER | \
611 DL_FLAG_SYNC_STATE_ONLY | \
612 DL_FLAG_INFERRED)
613
614#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
615 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
616
617/**
618 * device_link_add - Create a link between two devices.
619 * @consumer: Consumer end of the link.
620 * @supplier: Supplier end of the link.
621 * @flags: Link flags.
622 *
623 * The caller is responsible for the proper synchronization of the link creation
624 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
625 * runtime PM framework to take the link into account. Second, if the
626 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
627 * be forced into the active meta state and reference-counted upon the creation
628 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
629 * ignored.
630 *
631 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
632 * expected to release the link returned by it directly with the help of either
633 * device_link_del() or device_link_remove().
634 *
635 * If that flag is not set, however, the caller of this function is handing the
636 * management of the link over to the driver core entirely and its return value
637 * can only be used to check whether or not the link is present. In that case,
638 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
639 * flags can be used to indicate to the driver core when the link can be safely
640 * deleted. Namely, setting one of them in @flags indicates to the driver core
641 * that the link is not going to be used (by the given caller of this function)
642 * after unbinding the consumer or supplier driver, respectively, from its
643 * device, so the link can be deleted at that point. If none of them is set,
644 * the link will be maintained until one of the devices pointed to by it (either
645 * the consumer or the supplier) is unregistered.
646 *
647 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
648 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
649 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
650 * be used to request the driver core to automatically probe for a consumer
651 * driver after successfully binding a driver to the supplier device.
652 *
653 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
654 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
655 * the same time is invalid and will cause NULL to be returned upfront.
656 * However, if a device link between the given @consumer and @supplier pair
657 * exists already when this function is called for them, the existing link will
658 * be returned regardless of its current type and status (the link's flags may
659 * be modified then). The caller of this function is then expected to treat
660 * the link as though it has just been created, so (in particular) if
661 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
662 * explicitly when not needed any more (as stated above).
663 *
664 * A side effect of the link creation is re-ordering of dpm_list and the
665 * devices_kset list by moving the consumer device and all devices depending
666 * on it to the ends of these lists (that does not happen to devices that have
667 * not been registered when this function is called).
668 *
669 * The supplier device is required to be registered when this function is called
670 * and NULL will be returned if that is not the case. The consumer device need
671 * not be registered, however.
672 */
673struct device_link *device_link_add(struct device *consumer,
674 struct device *supplier, u32 flags)
675{
676 struct device_link *link;
677
678 if (!consumer || !supplier || consumer == supplier ||
679 flags & ~DL_ADD_VALID_FLAGS ||
680 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
681 (flags & DL_FLAG_SYNC_STATE_ONLY &&
682 (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) ||
683 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
684 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
685 DL_FLAG_AUTOREMOVE_SUPPLIER)))
686 return NULL;
687
688 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
689 if (pm_runtime_get_sync(supplier) < 0) {
690 pm_runtime_put_noidle(supplier);
691 return NULL;
692 }
693 }
694
695 if (!(flags & DL_FLAG_STATELESS))
696 flags |= DL_FLAG_MANAGED;
697
698 device_links_write_lock();
699 device_pm_lock();
700
701 /*
702 * If the supplier has not been fully registered yet or there is a
703 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
704 * the supplier already in the graph, return NULL. If the link is a
705 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
706 * because it only affects sync_state() callbacks.
707 */
708 if (!device_pm_initialized(supplier)
709 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
710 device_is_dependent(consumer, supplier))) {
711 link = NULL;
712 goto out;
713 }
714
715 /*
716 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
717 * So, only create it if the consumer hasn't probed yet.
718 */
719 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
720 consumer->links.status != DL_DEV_NO_DRIVER &&
721 consumer->links.status != DL_DEV_PROBING) {
722 link = NULL;
723 goto out;
724 }
725
726 /*
727 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
728 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
729 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
730 */
731 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
732 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
733
734 list_for_each_entry(link, &supplier->links.consumers, s_node) {
735 if (link->consumer != consumer)
736 continue;
737
738 if (link->flags & DL_FLAG_INFERRED &&
739 !(flags & DL_FLAG_INFERRED))
740 link->flags &= ~DL_FLAG_INFERRED;
741
742 if (flags & DL_FLAG_PM_RUNTIME) {
743 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
744 pm_runtime_new_link(consumer);
745 link->flags |= DL_FLAG_PM_RUNTIME;
746 }
747 if (flags & DL_FLAG_RPM_ACTIVE)
748 refcount_inc(&link->rpm_active);
749 }
750
751 if (flags & DL_FLAG_STATELESS) {
752 kref_get(&link->kref);
753 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
754 !(link->flags & DL_FLAG_STATELESS)) {
755 link->flags |= DL_FLAG_STATELESS;
756 goto reorder;
757 } else {
758 link->flags |= DL_FLAG_STATELESS;
759 goto out;
760 }
761 }
762
763 /*
764 * If the life time of the link following from the new flags is
765 * longer than indicated by the flags of the existing link,
766 * update the existing link to stay around longer.
767 */
768 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
769 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
770 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
771 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
772 }
773 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
774 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
775 DL_FLAG_AUTOREMOVE_SUPPLIER);
776 }
777 if (!(link->flags & DL_FLAG_MANAGED)) {
778 kref_get(&link->kref);
779 link->flags |= DL_FLAG_MANAGED;
780 device_link_init_status(link, consumer, supplier);
781 }
782 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
783 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
784 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
785 goto reorder;
786 }
787
788 goto out;
789 }
790
791 link = kzalloc(sizeof(*link), GFP_KERNEL);
792 if (!link)
793 goto out;
794
795 refcount_set(&link->rpm_active, 1);
796
797 get_device(supplier);
798 link->supplier = supplier;
799 INIT_LIST_HEAD(&link->s_node);
800 get_device(consumer);
801 link->consumer = consumer;
802 INIT_LIST_HEAD(&link->c_node);
803 link->flags = flags;
804 kref_init(&link->kref);
805
806 link->link_dev.class = &devlink_class;
807 device_set_pm_not_required(&link->link_dev);
808 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
809 dev_bus_name(supplier), dev_name(supplier),
810 dev_bus_name(consumer), dev_name(consumer));
811 if (device_register(&link->link_dev)) {
812 put_device(consumer);
813 put_device(supplier);
814 kfree(link);
815 link = NULL;
816 goto out;
817 }
818
819 if (flags & DL_FLAG_PM_RUNTIME) {
820 if (flags & DL_FLAG_RPM_ACTIVE)
821 refcount_inc(&link->rpm_active);
822
823 pm_runtime_new_link(consumer);
824 }
825
826 /* Determine the initial link state. */
827 if (flags & DL_FLAG_STATELESS)
828 link->status = DL_STATE_NONE;
829 else
830 device_link_init_status(link, consumer, supplier);
831
832 /*
833 * Some callers expect the link creation during consumer driver probe to
834 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
835 */
836 if (link->status == DL_STATE_CONSUMER_PROBE &&
837 flags & DL_FLAG_PM_RUNTIME)
838 pm_runtime_resume(supplier);
839
840 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
841 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
842
843 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
844 dev_dbg(consumer,
845 "Linked as a sync state only consumer to %s\n",
846 dev_name(supplier));
847 goto out;
848 }
849
850reorder:
851 /*
852 * Move the consumer and all of the devices depending on it to the end
853 * of dpm_list and the devices_kset list.
854 *
855 * It is necessary to hold dpm_list locked throughout all that or else
856 * we may end up suspending with a wrong ordering of it.
857 */
858 device_reorder_to_tail(consumer, NULL);
859
860 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
861
862out:
863 device_pm_unlock();
864 device_links_write_unlock();
865
866 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
867 pm_runtime_put(supplier);
868
869 return link;
870}
871EXPORT_SYMBOL_GPL(device_link_add);
872
873static void __device_link_del(struct kref *kref)
874{
875 struct device_link *link = container_of(kref, struct device_link, kref);
876
877 dev_dbg(link->consumer, "Dropping the link to %s\n",
878 dev_name(link->supplier));
879
880 pm_runtime_drop_link(link);
881
882 device_link_remove_from_lists(link);
883 device_unregister(&link->link_dev);
884}
885
886static void device_link_put_kref(struct device_link *link)
887{
888 if (link->flags & DL_FLAG_STATELESS)
889 kref_put(&link->kref, __device_link_del);
890 else if (!device_is_registered(link->consumer))
891 __device_link_del(&link->kref);
892 else
893 WARN(1, "Unable to drop a managed device link reference\n");
894}
895
896/**
897 * device_link_del - Delete a stateless link between two devices.
898 * @link: Device link to delete.
899 *
900 * The caller must ensure proper synchronization of this function with runtime
901 * PM. If the link was added multiple times, it needs to be deleted as often.
902 * Care is required for hotplugged devices: Their links are purged on removal
903 * and calling device_link_del() is then no longer allowed.
904 */
905void device_link_del(struct device_link *link)
906{
907 device_links_write_lock();
908 device_link_put_kref(link);
909 device_links_write_unlock();
910}
911EXPORT_SYMBOL_GPL(device_link_del);
912
913/**
914 * device_link_remove - Delete a stateless link between two devices.
915 * @consumer: Consumer end of the link.
916 * @supplier: Supplier end of the link.
917 *
918 * The caller must ensure proper synchronization of this function with runtime
919 * PM.
920 */
921void device_link_remove(void *consumer, struct device *supplier)
922{
923 struct device_link *link;
924
925 if (WARN_ON(consumer == supplier))
926 return;
927
928 device_links_write_lock();
929
930 list_for_each_entry(link, &supplier->links.consumers, s_node) {
931 if (link->consumer == consumer) {
932 device_link_put_kref(link);
933 break;
934 }
935 }
936
937 device_links_write_unlock();
938}
939EXPORT_SYMBOL_GPL(device_link_remove);
940
941static void device_links_missing_supplier(struct device *dev)
942{
943 struct device_link *link;
944
945 list_for_each_entry(link, &dev->links.suppliers, c_node) {
946 if (link->status != DL_STATE_CONSUMER_PROBE)
947 continue;
948
949 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
950 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
951 } else {
952 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
953 WRITE_ONCE(link->status, DL_STATE_DORMANT);
954 }
955 }
956}
957
958/**
959 * device_links_check_suppliers - Check presence of supplier drivers.
960 * @dev: Consumer device.
961 *
962 * Check links from this device to any suppliers. Walk the list of the device's
963 * links to suppliers and see if all of them are available. If not, simply
964 * return -EPROBE_DEFER.
965 *
966 * We need to guarantee that the supplier will not go away after the check has
967 * been positive here. It only can go away in __device_release_driver() and
968 * that function checks the device's links to consumers. This means we need to
969 * mark the link as "consumer probe in progress" to make the supplier removal
970 * wait for us to complete (or bad things may happen).
971 *
972 * Links without the DL_FLAG_MANAGED flag set are ignored.
973 */
974int device_links_check_suppliers(struct device *dev)
975{
976 struct device_link *link;
977 int ret = 0;
978
979 /*
980 * Device waiting for supplier to become available is not allowed to
981 * probe.
982 */
983 mutex_lock(&fwnode_link_lock);
984 if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
985 !fw_devlink_is_permissive()) {
986 dev_dbg(dev, "probe deferral - wait for supplier %pfwP\n",
987 list_first_entry(&dev->fwnode->suppliers,
988 struct fwnode_link,
989 c_hook)->supplier);
990 mutex_unlock(&fwnode_link_lock);
991 return -EPROBE_DEFER;
992 }
993 mutex_unlock(&fwnode_link_lock);
994
995 device_links_write_lock();
996
997 list_for_each_entry(link, &dev->links.suppliers, c_node) {
998 if (!(link->flags & DL_FLAG_MANAGED))
999 continue;
1000
1001 if (link->status != DL_STATE_AVAILABLE &&
1002 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1003 device_links_missing_supplier(dev);
1004 dev_dbg(dev, "probe deferral - supplier %s not ready\n",
1005 dev_name(link->supplier));
1006 ret = -EPROBE_DEFER;
1007 break;
1008 }
1009 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1010 }
1011 dev->links.status = DL_DEV_PROBING;
1012
1013 device_links_write_unlock();
1014 return ret;
1015}
1016
1017/**
1018 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1019 * @dev: Device to call sync_state() on
1020 * @list: List head to queue the @dev on
1021 *
1022 * Queues a device for a sync_state() callback when the device links write lock
1023 * isn't held. This allows the sync_state() execution flow to use device links
1024 * APIs. The caller must ensure this function is called with
1025 * device_links_write_lock() held.
1026 *
1027 * This function does a get_device() to make sure the device is not freed while
1028 * on this list.
1029 *
1030 * So the caller must also ensure that device_links_flush_sync_list() is called
1031 * as soon as the caller releases device_links_write_lock(). This is necessary
1032 * to make sure the sync_state() is called in a timely fashion and the
1033 * put_device() is called on this device.
1034 */
1035static void __device_links_queue_sync_state(struct device *dev,
1036 struct list_head *list)
1037{
1038 struct device_link *link;
1039
1040 if (!dev_has_sync_state(dev))
1041 return;
1042 if (dev->state_synced)
1043 return;
1044
1045 list_for_each_entry(link, &dev->links.consumers, s_node) {
1046 if (!(link->flags & DL_FLAG_MANAGED))
1047 continue;
1048 if (link->status != DL_STATE_ACTIVE)
1049 return;
1050 }
1051
1052 /*
1053 * Set the flag here to avoid adding the same device to a list more
1054 * than once. This can happen if new consumers get added to the device
1055 * and probed before the list is flushed.
1056 */
1057 dev->state_synced = true;
1058
1059 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1060 return;
1061
1062 get_device(dev);
1063 list_add_tail(&dev->links.defer_sync, list);
1064}
1065
1066/**
1067 * device_links_flush_sync_list - Call sync_state() on a list of devices
1068 * @list: List of devices to call sync_state() on
1069 * @dont_lock_dev: Device for which lock is already held by the caller
1070 *
1071 * Calls sync_state() on all the devices that have been queued for it. This
1072 * function is used in conjunction with __device_links_queue_sync_state(). The
1073 * @dont_lock_dev parameter is useful when this function is called from a
1074 * context where a device lock is already held.
1075 */
1076static void device_links_flush_sync_list(struct list_head *list,
1077 struct device *dont_lock_dev)
1078{
1079 struct device *dev, *tmp;
1080
1081 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1082 list_del_init(&dev->links.defer_sync);
1083
1084 if (dev != dont_lock_dev)
1085 device_lock(dev);
1086
1087 if (dev->bus->sync_state)
1088 dev->bus->sync_state(dev);
1089 else if (dev->driver && dev->driver->sync_state)
1090 dev->driver->sync_state(dev);
1091
1092 if (dev != dont_lock_dev)
1093 device_unlock(dev);
1094
1095 put_device(dev);
1096 }
1097}
1098
1099void device_links_supplier_sync_state_pause(void)
1100{
1101 device_links_write_lock();
1102 defer_sync_state_count++;
1103 device_links_write_unlock();
1104}
1105
1106void device_links_supplier_sync_state_resume(void)
1107{
1108 struct device *dev, *tmp;
1109 LIST_HEAD(sync_list);
1110
1111 device_links_write_lock();
1112 if (!defer_sync_state_count) {
1113 WARN(true, "Unmatched sync_state pause/resume!");
1114 goto out;
1115 }
1116 defer_sync_state_count--;
1117 if (defer_sync_state_count)
1118 goto out;
1119
1120 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1121 /*
1122 * Delete from deferred_sync list before queuing it to
1123 * sync_list because defer_sync is used for both lists.
1124 */
1125 list_del_init(&dev->links.defer_sync);
1126 __device_links_queue_sync_state(dev, &sync_list);
1127 }
1128out:
1129 device_links_write_unlock();
1130
1131 device_links_flush_sync_list(&sync_list, NULL);
1132}
1133
1134static int sync_state_resume_initcall(void)
1135{
1136 device_links_supplier_sync_state_resume();
1137 return 0;
1138}
1139late_initcall(sync_state_resume_initcall);
1140
1141static void __device_links_supplier_defer_sync(struct device *sup)
1142{
1143 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1144 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1145}
1146
1147static void device_link_drop_managed(struct device_link *link)
1148{
1149 link->flags &= ~DL_FLAG_MANAGED;
1150 WRITE_ONCE(link->status, DL_STATE_NONE);
1151 kref_put(&link->kref, __device_link_del);
1152}
1153
1154static ssize_t waiting_for_supplier_show(struct device *dev,
1155 struct device_attribute *attr,
1156 char *buf)
1157{
1158 bool val;
1159
1160 device_lock(dev);
1161 val = !list_empty(&dev->fwnode->suppliers);
1162 device_unlock(dev);
1163 return sysfs_emit(buf, "%u\n", val);
1164}
1165static DEVICE_ATTR_RO(waiting_for_supplier);
1166
1167/**
1168 * device_links_force_bind - Prepares device to be force bound
1169 * @dev: Consumer device.
1170 *
1171 * device_bind_driver() force binds a device to a driver without calling any
1172 * driver probe functions. So the consumer really isn't going to wait for any
1173 * supplier before it's bound to the driver. We still want the device link
1174 * states to be sensible when this happens.
1175 *
1176 * In preparation for device_bind_driver(), this function goes through each
1177 * supplier device links and checks if the supplier is bound. If it is, then
1178 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1179 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1180 */
1181void device_links_force_bind(struct device *dev)
1182{
1183 struct device_link *link, *ln;
1184
1185 device_links_write_lock();
1186
1187 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1188 if (!(link->flags & DL_FLAG_MANAGED))
1189 continue;
1190
1191 if (link->status != DL_STATE_AVAILABLE) {
1192 device_link_drop_managed(link);
1193 continue;
1194 }
1195 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1196 }
1197 dev->links.status = DL_DEV_PROBING;
1198
1199 device_links_write_unlock();
1200}
1201
1202/**
1203 * device_links_driver_bound - Update device links after probing its driver.
1204 * @dev: Device to update the links for.
1205 *
1206 * The probe has been successful, so update links from this device to any
1207 * consumers by changing their status to "available".
1208 *
1209 * Also change the status of @dev's links to suppliers to "active".
1210 *
1211 * Links without the DL_FLAG_MANAGED flag set are ignored.
1212 */
1213void device_links_driver_bound(struct device *dev)
1214{
1215 struct device_link *link, *ln;
1216 LIST_HEAD(sync_list);
1217
1218 /*
1219 * If a device binds successfully, it's expected to have created all
1220 * the device links it needs to or make new device links as it needs
1221 * them. So, fw_devlink no longer needs to create device links to any
1222 * of the device's suppliers.
1223 *
1224 * Also, if a child firmware node of this bound device is not added as
1225 * a device by now, assume it is never going to be added and make sure
1226 * other devices don't defer probe indefinitely by waiting for such a
1227 * child device.
1228 */
1229 if (dev->fwnode && dev->fwnode->dev == dev) {
1230 struct fwnode_handle *child;
1231 fwnode_links_purge_suppliers(dev->fwnode);
1232 fwnode_for_each_available_child_node(dev->fwnode, child)
1233 fw_devlink_purge_absent_suppliers(child);
1234 }
1235 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1236
1237 device_links_write_lock();
1238
1239 list_for_each_entry(link, &dev->links.consumers, s_node) {
1240 if (!(link->flags & DL_FLAG_MANAGED))
1241 continue;
1242
1243 /*
1244 * Links created during consumer probe may be in the "consumer
1245 * probe" state to start with if the supplier is still probing
1246 * when they are created and they may become "active" if the
1247 * consumer probe returns first. Skip them here.
1248 */
1249 if (link->status == DL_STATE_CONSUMER_PROBE ||
1250 link->status == DL_STATE_ACTIVE)
1251 continue;
1252
1253 WARN_ON(link->status != DL_STATE_DORMANT);
1254 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1255
1256 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1257 driver_deferred_probe_add(link->consumer);
1258 }
1259
1260 if (defer_sync_state_count)
1261 __device_links_supplier_defer_sync(dev);
1262 else
1263 __device_links_queue_sync_state(dev, &sync_list);
1264
1265 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1266 struct device *supplier;
1267
1268 if (!(link->flags & DL_FLAG_MANAGED))
1269 continue;
1270
1271 supplier = link->supplier;
1272 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1273 /*
1274 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1275 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1276 * save to drop the managed link completely.
1277 */
1278 device_link_drop_managed(link);
1279 } else {
1280 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1281 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1282 }
1283
1284 /*
1285 * This needs to be done even for the deleted
1286 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1287 * device link that was preventing the supplier from getting a
1288 * sync_state() call.
1289 */
1290 if (defer_sync_state_count)
1291 __device_links_supplier_defer_sync(supplier);
1292 else
1293 __device_links_queue_sync_state(supplier, &sync_list);
1294 }
1295
1296 dev->links.status = DL_DEV_DRIVER_BOUND;
1297
1298 device_links_write_unlock();
1299
1300 device_links_flush_sync_list(&sync_list, dev);
1301}
1302
1303/**
1304 * __device_links_no_driver - Update links of a device without a driver.
1305 * @dev: Device without a drvier.
1306 *
1307 * Delete all non-persistent links from this device to any suppliers.
1308 *
1309 * Persistent links stay around, but their status is changed to "available",
1310 * unless they already are in the "supplier unbind in progress" state in which
1311 * case they need not be updated.
1312 *
1313 * Links without the DL_FLAG_MANAGED flag set are ignored.
1314 */
1315static void __device_links_no_driver(struct device *dev)
1316{
1317 struct device_link *link, *ln;
1318
1319 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1320 if (!(link->flags & DL_FLAG_MANAGED))
1321 continue;
1322
1323 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1324 device_link_drop_managed(link);
1325 continue;
1326 }
1327
1328 if (link->status != DL_STATE_CONSUMER_PROBE &&
1329 link->status != DL_STATE_ACTIVE)
1330 continue;
1331
1332 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1333 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1334 } else {
1335 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1336 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1337 }
1338 }
1339
1340 dev->links.status = DL_DEV_NO_DRIVER;
1341}
1342
1343/**
1344 * device_links_no_driver - Update links after failing driver probe.
1345 * @dev: Device whose driver has just failed to probe.
1346 *
1347 * Clean up leftover links to consumers for @dev and invoke
1348 * %__device_links_no_driver() to update links to suppliers for it as
1349 * appropriate.
1350 *
1351 * Links without the DL_FLAG_MANAGED flag set are ignored.
1352 */
1353void device_links_no_driver(struct device *dev)
1354{
1355 struct device_link *link;
1356
1357 device_links_write_lock();
1358
1359 list_for_each_entry(link, &dev->links.consumers, s_node) {
1360 if (!(link->flags & DL_FLAG_MANAGED))
1361 continue;
1362
1363 /*
1364 * The probe has failed, so if the status of the link is
1365 * "consumer probe" or "active", it must have been added by
1366 * a probing consumer while this device was still probing.
1367 * Change its state to "dormant", as it represents a valid
1368 * relationship, but it is not functionally meaningful.
1369 */
1370 if (link->status == DL_STATE_CONSUMER_PROBE ||
1371 link->status == DL_STATE_ACTIVE)
1372 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1373 }
1374
1375 __device_links_no_driver(dev);
1376
1377 device_links_write_unlock();
1378}
1379
1380/**
1381 * device_links_driver_cleanup - Update links after driver removal.
1382 * @dev: Device whose driver has just gone away.
1383 *
1384 * Update links to consumers for @dev by changing their status to "dormant" and
1385 * invoke %__device_links_no_driver() to update links to suppliers for it as
1386 * appropriate.
1387 *
1388 * Links without the DL_FLAG_MANAGED flag set are ignored.
1389 */
1390void device_links_driver_cleanup(struct device *dev)
1391{
1392 struct device_link *link, *ln;
1393
1394 device_links_write_lock();
1395
1396 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1397 if (!(link->flags & DL_FLAG_MANAGED))
1398 continue;
1399
1400 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1401 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1402
1403 /*
1404 * autoremove the links between this @dev and its consumer
1405 * devices that are not active, i.e. where the link state
1406 * has moved to DL_STATE_SUPPLIER_UNBIND.
1407 */
1408 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1409 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1410 device_link_drop_managed(link);
1411
1412 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1413 }
1414
1415 list_del_init(&dev->links.defer_sync);
1416 __device_links_no_driver(dev);
1417
1418 device_links_write_unlock();
1419}
1420
1421/**
1422 * device_links_busy - Check if there are any busy links to consumers.
1423 * @dev: Device to check.
1424 *
1425 * Check each consumer of the device and return 'true' if its link's status
1426 * is one of "consumer probe" or "active" (meaning that the given consumer is
1427 * probing right now or its driver is present). Otherwise, change the link
1428 * state to "supplier unbind" to prevent the consumer from being probed
1429 * successfully going forward.
1430 *
1431 * Return 'false' if there are no probing or active consumers.
1432 *
1433 * Links without the DL_FLAG_MANAGED flag set are ignored.
1434 */
1435bool device_links_busy(struct device *dev)
1436{
1437 struct device_link *link;
1438 bool ret = false;
1439
1440 device_links_write_lock();
1441
1442 list_for_each_entry(link, &dev->links.consumers, s_node) {
1443 if (!(link->flags & DL_FLAG_MANAGED))
1444 continue;
1445
1446 if (link->status == DL_STATE_CONSUMER_PROBE
1447 || link->status == DL_STATE_ACTIVE) {
1448 ret = true;
1449 break;
1450 }
1451 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1452 }
1453
1454 dev->links.status = DL_DEV_UNBINDING;
1455
1456 device_links_write_unlock();
1457 return ret;
1458}
1459
1460/**
1461 * device_links_unbind_consumers - Force unbind consumers of the given device.
1462 * @dev: Device to unbind the consumers of.
1463 *
1464 * Walk the list of links to consumers for @dev and if any of them is in the
1465 * "consumer probe" state, wait for all device probes in progress to complete
1466 * and start over.
1467 *
1468 * If that's not the case, change the status of the link to "supplier unbind"
1469 * and check if the link was in the "active" state. If so, force the consumer
1470 * driver to unbind and start over (the consumer will not re-probe as we have
1471 * changed the state of the link already).
1472 *
1473 * Links without the DL_FLAG_MANAGED flag set are ignored.
1474 */
1475void device_links_unbind_consumers(struct device *dev)
1476{
1477 struct device_link *link;
1478
1479 start:
1480 device_links_write_lock();
1481
1482 list_for_each_entry(link, &dev->links.consumers, s_node) {
1483 enum device_link_state status;
1484
1485 if (!(link->flags & DL_FLAG_MANAGED) ||
1486 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1487 continue;
1488
1489 status = link->status;
1490 if (status == DL_STATE_CONSUMER_PROBE) {
1491 device_links_write_unlock();
1492
1493 wait_for_device_probe();
1494 goto start;
1495 }
1496 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1497 if (status == DL_STATE_ACTIVE) {
1498 struct device *consumer = link->consumer;
1499
1500 get_device(consumer);
1501
1502 device_links_write_unlock();
1503
1504 device_release_driver_internal(consumer, NULL,
1505 consumer->parent);
1506 put_device(consumer);
1507 goto start;
1508 }
1509 }
1510
1511 device_links_write_unlock();
1512}
1513
1514/**
1515 * device_links_purge - Delete existing links to other devices.
1516 * @dev: Target device.
1517 */
1518static void device_links_purge(struct device *dev)
1519{
1520 struct device_link *link, *ln;
1521
1522 if (dev->class == &devlink_class)
1523 return;
1524
1525 /*
1526 * Delete all of the remaining links from this device to any other
1527 * devices (either consumers or suppliers).
1528 */
1529 device_links_write_lock();
1530
1531 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1532 WARN_ON(link->status == DL_STATE_ACTIVE);
1533 __device_link_del(&link->kref);
1534 }
1535
1536 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1537 WARN_ON(link->status != DL_STATE_DORMANT &&
1538 link->status != DL_STATE_NONE);
1539 __device_link_del(&link->kref);
1540 }
1541
1542 device_links_write_unlock();
1543}
1544
1545#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1546 DL_FLAG_SYNC_STATE_ONLY)
1547#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1548 DL_FLAG_AUTOPROBE_CONSUMER)
1549#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1550 DL_FLAG_PM_RUNTIME)
1551
1552static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1553static int __init fw_devlink_setup(char *arg)
1554{
1555 if (!arg)
1556 return -EINVAL;
1557
1558 if (strcmp(arg, "off") == 0) {
1559 fw_devlink_flags = 0;
1560 } else if (strcmp(arg, "permissive") == 0) {
1561 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1562 } else if (strcmp(arg, "on") == 0) {
1563 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1564 } else if (strcmp(arg, "rpm") == 0) {
1565 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1566 }
1567 return 0;
1568}
1569early_param("fw_devlink", fw_devlink_setup);
1570
1571static bool fw_devlink_strict;
1572static int __init fw_devlink_strict_setup(char *arg)
1573{
1574 return strtobool(arg, &fw_devlink_strict);
1575}
1576early_param("fw_devlink.strict", fw_devlink_strict_setup);
1577
1578u32 fw_devlink_get_flags(void)
1579{
1580 return fw_devlink_flags;
1581}
1582
1583static bool fw_devlink_is_permissive(void)
1584{
1585 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1586}
1587
1588bool fw_devlink_is_strict(void)
1589{
1590 return fw_devlink_strict && !fw_devlink_is_permissive();
1591}
1592
1593static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1594{
1595 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1596 return;
1597
1598 fwnode_call_int_op(fwnode, add_links);
1599 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1600}
1601
1602static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1603{
1604 struct fwnode_handle *child = NULL;
1605
1606 fw_devlink_parse_fwnode(fwnode);
1607
1608 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1609 fw_devlink_parse_fwtree(child);
1610}
1611
1612static void fw_devlink_relax_link(struct device_link *link)
1613{
1614 if (!(link->flags & DL_FLAG_INFERRED))
1615 return;
1616
1617 if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE))
1618 return;
1619
1620 pm_runtime_drop_link(link);
1621 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1622 dev_dbg(link->consumer, "Relaxing link with %s\n",
1623 dev_name(link->supplier));
1624}
1625
1626static int fw_devlink_no_driver(struct device *dev, void *data)
1627{
1628 struct device_link *link = to_devlink(dev);
1629
1630 if (!link->supplier->can_match)
1631 fw_devlink_relax_link(link);
1632
1633 return 0;
1634}
1635
1636void fw_devlink_drivers_done(void)
1637{
1638 fw_devlink_drv_reg_done = true;
1639 device_links_write_lock();
1640 class_for_each_device(&devlink_class, NULL, NULL,
1641 fw_devlink_no_driver);
1642 device_links_write_unlock();
1643}
1644
1645static void fw_devlink_unblock_consumers(struct device *dev)
1646{
1647 struct device_link *link;
1648
1649 if (!fw_devlink_flags || fw_devlink_is_permissive())
1650 return;
1651
1652 device_links_write_lock();
1653 list_for_each_entry(link, &dev->links.consumers, s_node)
1654 fw_devlink_relax_link(link);
1655 device_links_write_unlock();
1656}
1657
1658/**
1659 * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links
1660 * @con: Device to check dependencies for.
1661 * @sup: Device to check against.
1662 *
1663 * Check if @sup depends on @con or any device dependent on it (its child or
1664 * its consumer etc). When such a cyclic dependency is found, convert all
1665 * device links created solely by fw_devlink into SYNC_STATE_ONLY device links.
1666 * This is the equivalent of doing fw_devlink=permissive just between the
1667 * devices in the cycle. We need to do this because, at this point, fw_devlink
1668 * can't tell which of these dependencies is not a real dependency.
1669 *
1670 * Return 1 if a cycle is found. Otherwise, return 0.
1671 */
1672static int fw_devlink_relax_cycle(struct device *con, void *sup)
1673{
1674 struct device_link *link;
1675 int ret;
1676
1677 if (con == sup)
1678 return 1;
1679
1680 ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
1681 if (ret)
1682 return ret;
1683
1684 list_for_each_entry(link, &con->links.consumers, s_node) {
1685 if ((link->flags & ~DL_FLAG_INFERRED) ==
1686 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
1687 continue;
1688
1689 if (!fw_devlink_relax_cycle(link->consumer, sup))
1690 continue;
1691
1692 ret = 1;
1693
1694 fw_devlink_relax_link(link);
1695 }
1696 return ret;
1697}
1698
1699/**
1700 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
1701 * @con: consumer device for the device link
1702 * @sup_handle: fwnode handle of supplier
1703 * @flags: devlink flags
1704 *
1705 * This function will try to create a device link between the consumer device
1706 * @con and the supplier device represented by @sup_handle.
1707 *
1708 * The supplier has to be provided as a fwnode because incorrect cycles in
1709 * fwnode links can sometimes cause the supplier device to never be created.
1710 * This function detects such cases and returns an error if it cannot create a
1711 * device link from the consumer to a missing supplier.
1712 *
1713 * Returns,
1714 * 0 on successfully creating a device link
1715 * -EINVAL if the device link cannot be created as expected
1716 * -EAGAIN if the device link cannot be created right now, but it may be
1717 * possible to do that in the future
1718 */
1719static int fw_devlink_create_devlink(struct device *con,
1720 struct fwnode_handle *sup_handle, u32 flags)
1721{
1722 struct device *sup_dev;
1723 int ret = 0;
1724
1725 /*
1726 * In some cases, a device P might also be a supplier to its child node
1727 * C. However, this would defer the probe of C until the probe of P
1728 * completes successfully. This is perfectly fine in the device driver
1729 * model. device_add() doesn't guarantee probe completion of the device
1730 * by the time it returns.
1731 *
1732 * However, there are a few drivers that assume C will finish probing
1733 * as soon as it's added and before P finishes probing. So, we provide
1734 * a flag to let fw_devlink know not to delay the probe of C until the
1735 * probe of P completes successfully.
1736 *
1737 * When such a flag is set, we can't create device links where P is the
1738 * supplier of C as that would delay the probe of C.
1739 */
1740 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
1741 fwnode_is_ancestor_of(sup_handle, con->fwnode))
1742 return -EINVAL;
1743
1744 sup_dev = get_dev_from_fwnode(sup_handle);
1745 if (sup_dev) {
1746 /*
1747 * If it's one of those drivers that don't actually bind to
1748 * their device using driver core, then don't wait on this
1749 * supplier device indefinitely.
1750 */
1751 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
1752 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
1753 ret = -EINVAL;
1754 goto out;
1755 }
1756
1757 /*
1758 * If this fails, it is due to cycles in device links. Just
1759 * give up on this link and treat it as invalid.
1760 */
1761 if (!device_link_add(con, sup_dev, flags) &&
1762 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
1763 dev_info(con, "Fixing up cyclic dependency with %s\n",
1764 dev_name(sup_dev));
1765 device_links_write_lock();
1766 fw_devlink_relax_cycle(con, sup_dev);
1767 device_links_write_unlock();
1768 device_link_add(con, sup_dev,
1769 FW_DEVLINK_FLAGS_PERMISSIVE);
1770 ret = -EINVAL;
1771 }
1772
1773 goto out;
1774 }
1775
1776 /* Supplier that's already initialized without a struct device. */
1777 if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
1778 return -EINVAL;
1779
1780 /*
1781 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
1782 * cycles. So cycle detection isn't necessary and shouldn't be
1783 * done.
1784 */
1785 if (flags & DL_FLAG_SYNC_STATE_ONLY)
1786 return -EAGAIN;
1787
1788 /*
1789 * If we can't find the supplier device from its fwnode, it might be
1790 * due to a cyclic dependency between fwnodes. Some of these cycles can
1791 * be broken by applying logic. Check for these types of cycles and
1792 * break them so that devices in the cycle probe properly.
1793 *
1794 * If the supplier's parent is dependent on the consumer, then the
1795 * consumer and supplier have a cyclic dependency. Since fw_devlink
1796 * can't tell which of the inferred dependencies are incorrect, don't
1797 * enforce probe ordering between any of the devices in this cyclic
1798 * dependency. Do this by relaxing all the fw_devlink device links in
1799 * this cycle and by treating the fwnode link between the consumer and
1800 * the supplier as an invalid dependency.
1801 */
1802 sup_dev = fwnode_get_next_parent_dev(sup_handle);
1803 if (sup_dev && device_is_dependent(con, sup_dev)) {
1804 dev_info(con, "Fixing up cyclic dependency with %pfwP (%s)\n",
1805 sup_handle, dev_name(sup_dev));
1806 device_links_write_lock();
1807 fw_devlink_relax_cycle(con, sup_dev);
1808 device_links_write_unlock();
1809 ret = -EINVAL;
1810 } else {
1811 /*
1812 * Can't check for cycles or no cycles. So let's try
1813 * again later.
1814 */
1815 ret = -EAGAIN;
1816 }
1817
1818out:
1819 put_device(sup_dev);
1820 return ret;
1821}
1822
1823/**
1824 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
1825 * @dev: Device that needs to be linked to its consumers
1826 *
1827 * This function looks at all the consumer fwnodes of @dev and creates device
1828 * links between the consumer device and @dev (supplier).
1829 *
1830 * If the consumer device has not been added yet, then this function creates a
1831 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
1832 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
1833 * sync_state() callback before the real consumer device gets to be added and
1834 * then probed.
1835 *
1836 * Once device links are created from the real consumer to @dev (supplier), the
1837 * fwnode links are deleted.
1838 */
1839static void __fw_devlink_link_to_consumers(struct device *dev)
1840{
1841 struct fwnode_handle *fwnode = dev->fwnode;
1842 struct fwnode_link *link, *tmp;
1843
1844 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
1845 u32 dl_flags = fw_devlink_get_flags();
1846 struct device *con_dev;
1847 bool own_link = true;
1848 int ret;
1849
1850 con_dev = get_dev_from_fwnode(link->consumer);
1851 /*
1852 * If consumer device is not available yet, make a "proxy"
1853 * SYNC_STATE_ONLY link from the consumer's parent device to
1854 * the supplier device. This is necessary to make sure the
1855 * supplier doesn't get a sync_state() callback before the real
1856 * consumer can create a device link to the supplier.
1857 *
1858 * This proxy link step is needed to handle the case where the
1859 * consumer's parent device is added before the supplier.
1860 */
1861 if (!con_dev) {
1862 con_dev = fwnode_get_next_parent_dev(link->consumer);
1863 /*
1864 * However, if the consumer's parent device is also the
1865 * parent of the supplier, don't create a
1866 * consumer-supplier link from the parent to its child
1867 * device. Such a dependency is impossible.
1868 */
1869 if (con_dev &&
1870 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
1871 put_device(con_dev);
1872 con_dev = NULL;
1873 } else {
1874 own_link = false;
1875 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1876 }
1877 }
1878
1879 if (!con_dev)
1880 continue;
1881
1882 ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags);
1883 put_device(con_dev);
1884 if (!own_link || ret == -EAGAIN)
1885 continue;
1886
1887 list_del(&link->s_hook);
1888 list_del(&link->c_hook);
1889 kfree(link);
1890 }
1891}
1892
1893/**
1894 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
1895 * @dev: The consumer device that needs to be linked to its suppliers
1896 * @fwnode: Root of the fwnode tree that is used to create device links
1897 *
1898 * This function looks at all the supplier fwnodes of fwnode tree rooted at
1899 * @fwnode and creates device links between @dev (consumer) and all the
1900 * supplier devices of the entire fwnode tree at @fwnode.
1901 *
1902 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
1903 * and the real suppliers of @dev. Once these device links are created, the
1904 * fwnode links are deleted. When such device links are successfully created,
1905 * this function is called recursively on those supplier devices. This is
1906 * needed to detect and break some invalid cycles in fwnode links. See
1907 * fw_devlink_create_devlink() for more details.
1908 *
1909 * In addition, it also looks at all the suppliers of the entire fwnode tree
1910 * because some of the child devices of @dev that have not been added yet
1911 * (because @dev hasn't probed) might already have their suppliers added to
1912 * driver core. So, this function creates SYNC_STATE_ONLY device links between
1913 * @dev (consumer) and these suppliers to make sure they don't execute their
1914 * sync_state() callbacks before these child devices have a chance to create
1915 * their device links. The fwnode links that correspond to the child devices
1916 * aren't delete because they are needed later to create the device links
1917 * between the real consumer and supplier devices.
1918 */
1919static void __fw_devlink_link_to_suppliers(struct device *dev,
1920 struct fwnode_handle *fwnode)
1921{
1922 bool own_link = (dev->fwnode == fwnode);
1923 struct fwnode_link *link, *tmp;
1924 struct fwnode_handle *child = NULL;
1925 u32 dl_flags;
1926
1927 if (own_link)
1928 dl_flags = fw_devlink_get_flags();
1929 else
1930 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1931
1932 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
1933 int ret;
1934 struct device *sup_dev;
1935 struct fwnode_handle *sup = link->supplier;
1936
1937 ret = fw_devlink_create_devlink(dev, sup, dl_flags);
1938 if (!own_link || ret == -EAGAIN)
1939 continue;
1940
1941 list_del(&link->s_hook);
1942 list_del(&link->c_hook);
1943 kfree(link);
1944
1945 /* If no device link was created, nothing more to do. */
1946 if (ret)
1947 continue;
1948
1949 /*
1950 * If a device link was successfully created to a supplier, we
1951 * now need to try and link the supplier to all its suppliers.
1952 *
1953 * This is needed to detect and delete false dependencies in
1954 * fwnode links that haven't been converted to a device link
1955 * yet. See comments in fw_devlink_create_devlink() for more
1956 * details on the false dependency.
1957 *
1958 * Without deleting these false dependencies, some devices will
1959 * never probe because they'll keep waiting for their false
1960 * dependency fwnode links to be converted to device links.
1961 */
1962 sup_dev = get_dev_from_fwnode(sup);
1963 __fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode);
1964 put_device(sup_dev);
1965 }
1966
1967 /*
1968 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
1969 * all the descendants. This proxy link step is needed to handle the
1970 * case where the supplier is added before the consumer's parent device
1971 * (@dev).
1972 */
1973 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1974 __fw_devlink_link_to_suppliers(dev, child);
1975}
1976
1977static void fw_devlink_link_device(struct device *dev)
1978{
1979 struct fwnode_handle *fwnode = dev->fwnode;
1980
1981 if (!fw_devlink_flags)
1982 return;
1983
1984 fw_devlink_parse_fwtree(fwnode);
1985
1986 mutex_lock(&fwnode_link_lock);
1987 __fw_devlink_link_to_consumers(dev);
1988 __fw_devlink_link_to_suppliers(dev, fwnode);
1989 mutex_unlock(&fwnode_link_lock);
1990}
1991
1992/* Device links support end. */
1993
1994int (*platform_notify)(struct device *dev) = NULL;
1995int (*platform_notify_remove)(struct device *dev) = NULL;
1996static struct kobject *dev_kobj;
1997struct kobject *sysfs_dev_char_kobj;
1998struct kobject *sysfs_dev_block_kobj;
1999
2000static DEFINE_MUTEX(device_hotplug_lock);
2001
2002void lock_device_hotplug(void)
2003{
2004 mutex_lock(&device_hotplug_lock);
2005}
2006
2007void unlock_device_hotplug(void)
2008{
2009 mutex_unlock(&device_hotplug_lock);
2010}
2011
2012int lock_device_hotplug_sysfs(void)
2013{
2014 if (mutex_trylock(&device_hotplug_lock))
2015 return 0;
2016
2017 /* Avoid busy looping (5 ms of sleep should do). */
2018 msleep(5);
2019 return restart_syscall();
2020}
2021
2022#ifdef CONFIG_BLOCK
2023static inline int device_is_not_partition(struct device *dev)
2024{
2025 return !(dev->type == &part_type);
2026}
2027#else
2028static inline int device_is_not_partition(struct device *dev)
2029{
2030 return 1;
2031}
2032#endif
2033
2034static int
2035device_platform_notify(struct device *dev, enum kobject_action action)
2036{
2037 int ret;
2038
2039 ret = acpi_platform_notify(dev, action);
2040 if (ret)
2041 return ret;
2042
2043 ret = software_node_notify(dev, action);
2044 if (ret)
2045 return ret;
2046
2047 if (platform_notify && action == KOBJ_ADD)
2048 platform_notify(dev);
2049 else if (platform_notify_remove && action == KOBJ_REMOVE)
2050 platform_notify_remove(dev);
2051 return 0;
2052}
2053
2054/**
2055 * dev_driver_string - Return a device's driver name, if at all possible
2056 * @dev: struct device to get the name of
2057 *
2058 * Will return the device's driver's name if it is bound to a device. If
2059 * the device is not bound to a driver, it will return the name of the bus
2060 * it is attached to. If it is not attached to a bus either, an empty
2061 * string will be returned.
2062 */
2063const char *dev_driver_string(const struct device *dev)
2064{
2065 struct device_driver *drv;
2066
2067 /* dev->driver can change to NULL underneath us because of unbinding,
2068 * so be careful about accessing it. dev->bus and dev->class should
2069 * never change once they are set, so they don't need special care.
2070 */
2071 drv = READ_ONCE(dev->driver);
2072 return drv ? drv->name : dev_bus_name(dev);
2073}
2074EXPORT_SYMBOL(dev_driver_string);
2075
2076#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2077
2078static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2079 char *buf)
2080{
2081 struct device_attribute *dev_attr = to_dev_attr(attr);
2082 struct device *dev = kobj_to_dev(kobj);
2083 ssize_t ret = -EIO;
2084
2085 if (dev_attr->show)
2086 ret = dev_attr->show(dev, dev_attr, buf);
2087 if (ret >= (ssize_t)PAGE_SIZE) {
2088 printk("dev_attr_show: %pS returned bad count\n",
2089 dev_attr->show);
2090 }
2091 return ret;
2092}
2093
2094static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2095 const char *buf, size_t count)
2096{
2097 struct device_attribute *dev_attr = to_dev_attr(attr);
2098 struct device *dev = kobj_to_dev(kobj);
2099 ssize_t ret = -EIO;
2100
2101 if (dev_attr->store)
2102 ret = dev_attr->store(dev, dev_attr, buf, count);
2103 return ret;
2104}
2105
2106static const struct sysfs_ops dev_sysfs_ops = {
2107 .show = dev_attr_show,
2108 .store = dev_attr_store,
2109};
2110
2111#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2112
2113ssize_t device_store_ulong(struct device *dev,
2114 struct device_attribute *attr,
2115 const char *buf, size_t size)
2116{
2117 struct dev_ext_attribute *ea = to_ext_attr(attr);
2118 int ret;
2119 unsigned long new;
2120
2121 ret = kstrtoul(buf, 0, &new);
2122 if (ret)
2123 return ret;
2124 *(unsigned long *)(ea->var) = new;
2125 /* Always return full write size even if we didn't consume all */
2126 return size;
2127}
2128EXPORT_SYMBOL_GPL(device_store_ulong);
2129
2130ssize_t device_show_ulong(struct device *dev,
2131 struct device_attribute *attr,
2132 char *buf)
2133{
2134 struct dev_ext_attribute *ea = to_ext_attr(attr);
2135 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2136}
2137EXPORT_SYMBOL_GPL(device_show_ulong);
2138
2139ssize_t device_store_int(struct device *dev,
2140 struct device_attribute *attr,
2141 const char *buf, size_t size)
2142{
2143 struct dev_ext_attribute *ea = to_ext_attr(attr);
2144 int ret;
2145 long new;
2146
2147 ret = kstrtol(buf, 0, &new);
2148 if (ret)
2149 return ret;
2150
2151 if (new > INT_MAX || new < INT_MIN)
2152 return -EINVAL;
2153 *(int *)(ea->var) = new;
2154 /* Always return full write size even if we didn't consume all */
2155 return size;
2156}
2157EXPORT_SYMBOL_GPL(device_store_int);
2158
2159ssize_t device_show_int(struct device *dev,
2160 struct device_attribute *attr,
2161 char *buf)
2162{
2163 struct dev_ext_attribute *ea = to_ext_attr(attr);
2164
2165 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2166}
2167EXPORT_SYMBOL_GPL(device_show_int);
2168
2169ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2170 const char *buf, size_t size)
2171{
2172 struct dev_ext_attribute *ea = to_ext_attr(attr);
2173
2174 if (strtobool(buf, ea->var) < 0)
2175 return -EINVAL;
2176
2177 return size;
2178}
2179EXPORT_SYMBOL_GPL(device_store_bool);
2180
2181ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2182 char *buf)
2183{
2184 struct dev_ext_attribute *ea = to_ext_attr(attr);
2185
2186 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2187}
2188EXPORT_SYMBOL_GPL(device_show_bool);
2189
2190/**
2191 * device_release - free device structure.
2192 * @kobj: device's kobject.
2193 *
2194 * This is called once the reference count for the object
2195 * reaches 0. We forward the call to the device's release
2196 * method, which should handle actually freeing the structure.
2197 */
2198static void device_release(struct kobject *kobj)
2199{
2200 struct device *dev = kobj_to_dev(kobj);
2201 struct device_private *p = dev->p;
2202
2203 /*
2204 * Some platform devices are driven without driver attached
2205 * and managed resources may have been acquired. Make sure
2206 * all resources are released.
2207 *
2208 * Drivers still can add resources into device after device
2209 * is deleted but alive, so release devres here to avoid
2210 * possible memory leak.
2211 */
2212 devres_release_all(dev);
2213
2214 kfree(dev->dma_range_map);
2215
2216 if (dev->release)
2217 dev->release(dev);
2218 else if (dev->type && dev->type->release)
2219 dev->type->release(dev);
2220 else if (dev->class && dev->class->dev_release)
2221 dev->class->dev_release(dev);
2222 else
2223 WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
2224 dev_name(dev));
2225 kfree(p);
2226}
2227
2228static const void *device_namespace(struct kobject *kobj)
2229{
2230 struct device *dev = kobj_to_dev(kobj);
2231 const void *ns = NULL;
2232
2233 if (dev->class && dev->class->ns_type)
2234 ns = dev->class->namespace(dev);
2235
2236 return ns;
2237}
2238
2239static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2240{
2241 struct device *dev = kobj_to_dev(kobj);
2242
2243 if (dev->class && dev->class->get_ownership)
2244 dev->class->get_ownership(dev, uid, gid);
2245}
2246
2247static struct kobj_type device_ktype = {
2248 .release = device_release,
2249 .sysfs_ops = &dev_sysfs_ops,
2250 .namespace = device_namespace,
2251 .get_ownership = device_get_ownership,
2252};
2253
2254
2255static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
2256{
2257 struct kobj_type *ktype = get_ktype(kobj);
2258
2259 if (ktype == &device_ktype) {
2260 struct device *dev = kobj_to_dev(kobj);
2261 if (dev->bus)
2262 return 1;
2263 if (dev->class)
2264 return 1;
2265 }
2266 return 0;
2267}
2268
2269static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
2270{
2271 struct device *dev = kobj_to_dev(kobj);
2272
2273 if (dev->bus)
2274 return dev->bus->name;
2275 if (dev->class)
2276 return dev->class->name;
2277 return NULL;
2278}
2279
2280static int dev_uevent(struct kset *kset, struct kobject *kobj,
2281 struct kobj_uevent_env *env)
2282{
2283 struct device *dev = kobj_to_dev(kobj);
2284 int retval = 0;
2285
2286 /* add device node properties if present */
2287 if (MAJOR(dev->devt)) {
2288 const char *tmp;
2289 const char *name;
2290 umode_t mode = 0;
2291 kuid_t uid = GLOBAL_ROOT_UID;
2292 kgid_t gid = GLOBAL_ROOT_GID;
2293
2294 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2295 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2296 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2297 if (name) {
2298 add_uevent_var(env, "DEVNAME=%s", name);
2299 if (mode)
2300 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2301 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2302 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2303 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2304 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2305 kfree(tmp);
2306 }
2307 }
2308
2309 if (dev->type && dev->type->name)
2310 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2311
2312 if (dev->driver)
2313 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2314
2315 /* Add common DT information about the device */
2316 of_device_uevent(dev, env);
2317
2318 /* have the bus specific function add its stuff */
2319 if (dev->bus && dev->bus->uevent) {
2320 retval = dev->bus->uevent(dev, env);
2321 if (retval)
2322 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2323 dev_name(dev), __func__, retval);
2324 }
2325
2326 /* have the class specific function add its stuff */
2327 if (dev->class && dev->class->dev_uevent) {
2328 retval = dev->class->dev_uevent(dev, env);
2329 if (retval)
2330 pr_debug("device: '%s': %s: class uevent() "
2331 "returned %d\n", dev_name(dev),
2332 __func__, retval);
2333 }
2334
2335 /* have the device type specific function add its stuff */
2336 if (dev->type && dev->type->uevent) {
2337 retval = dev->type->uevent(dev, env);
2338 if (retval)
2339 pr_debug("device: '%s': %s: dev_type uevent() "
2340 "returned %d\n", dev_name(dev),
2341 __func__, retval);
2342 }
2343
2344 return retval;
2345}
2346
2347static const struct kset_uevent_ops device_uevent_ops = {
2348 .filter = dev_uevent_filter,
2349 .name = dev_uevent_name,
2350 .uevent = dev_uevent,
2351};
2352
2353static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2354 char *buf)
2355{
2356 struct kobject *top_kobj;
2357 struct kset *kset;
2358 struct kobj_uevent_env *env = NULL;
2359 int i;
2360 int len = 0;
2361 int retval;
2362
2363 /* search the kset, the device belongs to */
2364 top_kobj = &dev->kobj;
2365 while (!top_kobj->kset && top_kobj->parent)
2366 top_kobj = top_kobj->parent;
2367 if (!top_kobj->kset)
2368 goto out;
2369
2370 kset = top_kobj->kset;
2371 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2372 goto out;
2373
2374 /* respect filter */
2375 if (kset->uevent_ops && kset->uevent_ops->filter)
2376 if (!kset->uevent_ops->filter(kset, &dev->kobj))
2377 goto out;
2378
2379 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2380 if (!env)
2381 return -ENOMEM;
2382
2383 /* let the kset specific function add its keys */
2384 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
2385 if (retval)
2386 goto out;
2387
2388 /* copy keys to file */
2389 for (i = 0; i < env->envp_idx; i++)
2390 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2391out:
2392 kfree(env);
2393 return len;
2394}
2395
2396static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2397 const char *buf, size_t count)
2398{
2399 int rc;
2400
2401 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2402
2403 if (rc) {
2404 dev_err(dev, "uevent: failed to send synthetic uevent\n");
2405 return rc;
2406 }
2407
2408 return count;
2409}
2410static DEVICE_ATTR_RW(uevent);
2411
2412static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2413 char *buf)
2414{
2415 bool val;
2416
2417 device_lock(dev);
2418 val = !dev->offline;
2419 device_unlock(dev);
2420 return sysfs_emit(buf, "%u\n", val);
2421}
2422
2423static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2424 const char *buf, size_t count)
2425{
2426 bool val;
2427 int ret;
2428
2429 ret = strtobool(buf, &val);
2430 if (ret < 0)
2431 return ret;
2432
2433 ret = lock_device_hotplug_sysfs();
2434 if (ret)
2435 return ret;
2436
2437 ret = val ? device_online(dev) : device_offline(dev);
2438 unlock_device_hotplug();
2439 return ret < 0 ? ret : count;
2440}
2441static DEVICE_ATTR_RW(online);
2442
2443static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2444 char *buf)
2445{
2446 const char *loc;
2447
2448 switch (dev->removable) {
2449 case DEVICE_REMOVABLE:
2450 loc = "removable";
2451 break;
2452 case DEVICE_FIXED:
2453 loc = "fixed";
2454 break;
2455 default:
2456 loc = "unknown";
2457 }
2458 return sysfs_emit(buf, "%s\n", loc);
2459}
2460static DEVICE_ATTR_RO(removable);
2461
2462int device_add_groups(struct device *dev, const struct attribute_group **groups)
2463{
2464 return sysfs_create_groups(&dev->kobj, groups);
2465}
2466EXPORT_SYMBOL_GPL(device_add_groups);
2467
2468void device_remove_groups(struct device *dev,
2469 const struct attribute_group **groups)
2470{
2471 sysfs_remove_groups(&dev->kobj, groups);
2472}
2473EXPORT_SYMBOL_GPL(device_remove_groups);
2474
2475union device_attr_group_devres {
2476 const struct attribute_group *group;
2477 const struct attribute_group **groups;
2478};
2479
2480static int devm_attr_group_match(struct device *dev, void *res, void *data)
2481{
2482 return ((union device_attr_group_devres *)res)->group == data;
2483}
2484
2485static void devm_attr_group_remove(struct device *dev, void *res)
2486{
2487 union device_attr_group_devres *devres = res;
2488 const struct attribute_group *group = devres->group;
2489
2490 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2491 sysfs_remove_group(&dev->kobj, group);
2492}
2493
2494static void devm_attr_groups_remove(struct device *dev, void *res)
2495{
2496 union device_attr_group_devres *devres = res;
2497 const struct attribute_group **groups = devres->groups;
2498
2499 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2500 sysfs_remove_groups(&dev->kobj, groups);
2501}
2502
2503/**
2504 * devm_device_add_group - given a device, create a managed attribute group
2505 * @dev: The device to create the group for
2506 * @grp: The attribute group to create
2507 *
2508 * This function creates a group for the first time. It will explicitly
2509 * warn and error if any of the attribute files being created already exist.
2510 *
2511 * Returns 0 on success or error code on failure.
2512 */
2513int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2514{
2515 union device_attr_group_devres *devres;
2516 int error;
2517
2518 devres = devres_alloc(devm_attr_group_remove,
2519 sizeof(*devres), GFP_KERNEL);
2520 if (!devres)
2521 return -ENOMEM;
2522
2523 error = sysfs_create_group(&dev->kobj, grp);
2524 if (error) {
2525 devres_free(devres);
2526 return error;
2527 }
2528
2529 devres->group = grp;
2530 devres_add(dev, devres);
2531 return 0;
2532}
2533EXPORT_SYMBOL_GPL(devm_device_add_group);
2534
2535/**
2536 * devm_device_remove_group: remove a managed group from a device
2537 * @dev: device to remove the group from
2538 * @grp: group to remove
2539 *
2540 * This function removes a group of attributes from a device. The attributes
2541 * previously have to have been created for this group, otherwise it will fail.
2542 */
2543void devm_device_remove_group(struct device *dev,
2544 const struct attribute_group *grp)
2545{
2546 WARN_ON(devres_release(dev, devm_attr_group_remove,
2547 devm_attr_group_match,
2548 /* cast away const */ (void *)grp));
2549}
2550EXPORT_SYMBOL_GPL(devm_device_remove_group);
2551
2552/**
2553 * devm_device_add_groups - create a bunch of managed attribute groups
2554 * @dev: The device to create the group for
2555 * @groups: The attribute groups to create, NULL terminated
2556 *
2557 * This function creates a bunch of managed attribute groups. If an error
2558 * occurs when creating a group, all previously created groups will be
2559 * removed, unwinding everything back to the original state when this
2560 * function was called. It will explicitly warn and error if any of the
2561 * attribute files being created already exist.
2562 *
2563 * Returns 0 on success or error code from sysfs_create_group on failure.
2564 */
2565int devm_device_add_groups(struct device *dev,
2566 const struct attribute_group **groups)
2567{
2568 union device_attr_group_devres *devres;
2569 int error;
2570
2571 devres = devres_alloc(devm_attr_groups_remove,
2572 sizeof(*devres), GFP_KERNEL);
2573 if (!devres)
2574 return -ENOMEM;
2575
2576 error = sysfs_create_groups(&dev->kobj, groups);
2577 if (error) {
2578 devres_free(devres);
2579 return error;
2580 }
2581
2582 devres->groups = groups;
2583 devres_add(dev, devres);
2584 return 0;
2585}
2586EXPORT_SYMBOL_GPL(devm_device_add_groups);
2587
2588/**
2589 * devm_device_remove_groups - remove a list of managed groups
2590 *
2591 * @dev: The device for the groups to be removed from
2592 * @groups: NULL terminated list of groups to be removed
2593 *
2594 * If groups is not NULL, remove the specified groups from the device.
2595 */
2596void devm_device_remove_groups(struct device *dev,
2597 const struct attribute_group **groups)
2598{
2599 WARN_ON(devres_release(dev, devm_attr_groups_remove,
2600 devm_attr_group_match,
2601 /* cast away const */ (void *)groups));
2602}
2603EXPORT_SYMBOL_GPL(devm_device_remove_groups);
2604
2605static int device_add_attrs(struct device *dev)
2606{
2607 struct class *class = dev->class;
2608 const struct device_type *type = dev->type;
2609 int error;
2610
2611 if (class) {
2612 error = device_add_groups(dev, class->dev_groups);
2613 if (error)
2614 return error;
2615 }
2616
2617 if (type) {
2618 error = device_add_groups(dev, type->groups);
2619 if (error)
2620 goto err_remove_class_groups;
2621 }
2622
2623 error = device_add_groups(dev, dev->groups);
2624 if (error)
2625 goto err_remove_type_groups;
2626
2627 if (device_supports_offline(dev) && !dev->offline_disabled) {
2628 error = device_create_file(dev, &dev_attr_online);
2629 if (error)
2630 goto err_remove_dev_groups;
2631 }
2632
2633 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2634 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2635 if (error)
2636 goto err_remove_dev_online;
2637 }
2638
2639 if (dev_removable_is_valid(dev)) {
2640 error = device_create_file(dev, &dev_attr_removable);
2641 if (error)
2642 goto err_remove_dev_waiting_for_supplier;
2643 }
2644
2645 return 0;
2646
2647 err_remove_dev_waiting_for_supplier:
2648 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2649 err_remove_dev_online:
2650 device_remove_file(dev, &dev_attr_online);
2651 err_remove_dev_groups:
2652 device_remove_groups(dev, dev->groups);
2653 err_remove_type_groups:
2654 if (type)
2655 device_remove_groups(dev, type->groups);
2656 err_remove_class_groups:
2657 if (class)
2658 device_remove_groups(dev, class->dev_groups);
2659
2660 return error;
2661}
2662
2663static void device_remove_attrs(struct device *dev)
2664{
2665 struct class *class = dev->class;
2666 const struct device_type *type = dev->type;
2667
2668 device_remove_file(dev, &dev_attr_removable);
2669 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2670 device_remove_file(dev, &dev_attr_online);
2671 device_remove_groups(dev, dev->groups);
2672
2673 if (type)
2674 device_remove_groups(dev, type->groups);
2675
2676 if (class)
2677 device_remove_groups(dev, class->dev_groups);
2678}
2679
2680static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2681 char *buf)
2682{
2683 return print_dev_t(buf, dev->devt);
2684}
2685static DEVICE_ATTR_RO(dev);
2686
2687/* /sys/devices/ */
2688struct kset *devices_kset;
2689
2690/**
2691 * devices_kset_move_before - Move device in the devices_kset's list.
2692 * @deva: Device to move.
2693 * @devb: Device @deva should come before.
2694 */
2695static void devices_kset_move_before(struct device *deva, struct device *devb)
2696{
2697 if (!devices_kset)
2698 return;
2699 pr_debug("devices_kset: Moving %s before %s\n",
2700 dev_name(deva), dev_name(devb));
2701 spin_lock(&devices_kset->list_lock);
2702 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2703 spin_unlock(&devices_kset->list_lock);
2704}
2705
2706/**
2707 * devices_kset_move_after - Move device in the devices_kset's list.
2708 * @deva: Device to move
2709 * @devb: Device @deva should come after.
2710 */
2711static void devices_kset_move_after(struct device *deva, struct device *devb)
2712{
2713 if (!devices_kset)
2714 return;
2715 pr_debug("devices_kset: Moving %s after %s\n",
2716 dev_name(deva), dev_name(devb));
2717 spin_lock(&devices_kset->list_lock);
2718 list_move(&deva->kobj.entry, &devb->kobj.entry);
2719 spin_unlock(&devices_kset->list_lock);
2720}
2721
2722/**
2723 * devices_kset_move_last - move the device to the end of devices_kset's list.
2724 * @dev: device to move
2725 */
2726void devices_kset_move_last(struct device *dev)
2727{
2728 if (!devices_kset)
2729 return;
2730 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2731 spin_lock(&devices_kset->list_lock);
2732 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2733 spin_unlock(&devices_kset->list_lock);
2734}
2735
2736/**
2737 * device_create_file - create sysfs attribute file for device.
2738 * @dev: device.
2739 * @attr: device attribute descriptor.
2740 */
2741int device_create_file(struct device *dev,
2742 const struct device_attribute *attr)
2743{
2744 int error = 0;
2745
2746 if (dev) {
2747 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2748 "Attribute %s: write permission without 'store'\n",
2749 attr->attr.name);
2750 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2751 "Attribute %s: read permission without 'show'\n",
2752 attr->attr.name);
2753 error = sysfs_create_file(&dev->kobj, &attr->attr);
2754 }
2755
2756 return error;
2757}
2758EXPORT_SYMBOL_GPL(device_create_file);
2759
2760/**
2761 * device_remove_file - remove sysfs attribute file.
2762 * @dev: device.
2763 * @attr: device attribute descriptor.
2764 */
2765void device_remove_file(struct device *dev,
2766 const struct device_attribute *attr)
2767{
2768 if (dev)
2769 sysfs_remove_file(&dev->kobj, &attr->attr);
2770}
2771EXPORT_SYMBOL_GPL(device_remove_file);
2772
2773/**
2774 * device_remove_file_self - remove sysfs attribute file from its own method.
2775 * @dev: device.
2776 * @attr: device attribute descriptor.
2777 *
2778 * See kernfs_remove_self() for details.
2779 */
2780bool device_remove_file_self(struct device *dev,
2781 const struct device_attribute *attr)
2782{
2783 if (dev)
2784 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2785 else
2786 return false;
2787}
2788EXPORT_SYMBOL_GPL(device_remove_file_self);
2789
2790/**
2791 * device_create_bin_file - create sysfs binary attribute file for device.
2792 * @dev: device.
2793 * @attr: device binary attribute descriptor.
2794 */
2795int device_create_bin_file(struct device *dev,
2796 const struct bin_attribute *attr)
2797{
2798 int error = -EINVAL;
2799 if (dev)
2800 error = sysfs_create_bin_file(&dev->kobj, attr);
2801 return error;
2802}
2803EXPORT_SYMBOL_GPL(device_create_bin_file);
2804
2805/**
2806 * device_remove_bin_file - remove sysfs binary attribute file
2807 * @dev: device.
2808 * @attr: device binary attribute descriptor.
2809 */
2810void device_remove_bin_file(struct device *dev,
2811 const struct bin_attribute *attr)
2812{
2813 if (dev)
2814 sysfs_remove_bin_file(&dev->kobj, attr);
2815}
2816EXPORT_SYMBOL_GPL(device_remove_bin_file);
2817
2818static void klist_children_get(struct klist_node *n)
2819{
2820 struct device_private *p = to_device_private_parent(n);
2821 struct device *dev = p->device;
2822
2823 get_device(dev);
2824}
2825
2826static void klist_children_put(struct klist_node *n)
2827{
2828 struct device_private *p = to_device_private_parent(n);
2829 struct device *dev = p->device;
2830
2831 put_device(dev);
2832}
2833
2834/**
2835 * device_initialize - init device structure.
2836 * @dev: device.
2837 *
2838 * This prepares the device for use by other layers by initializing
2839 * its fields.
2840 * It is the first half of device_register(), if called by
2841 * that function, though it can also be called separately, so one
2842 * may use @dev's fields. In particular, get_device()/put_device()
2843 * may be used for reference counting of @dev after calling this
2844 * function.
2845 *
2846 * All fields in @dev must be initialized by the caller to 0, except
2847 * for those explicitly set to some other value. The simplest
2848 * approach is to use kzalloc() to allocate the structure containing
2849 * @dev.
2850 *
2851 * NOTE: Use put_device() to give up your reference instead of freeing
2852 * @dev directly once you have called this function.
2853 */
2854void device_initialize(struct device *dev)
2855{
2856 dev->kobj.kset = devices_kset;
2857 kobject_init(&dev->kobj, &device_ktype);
2858 INIT_LIST_HEAD(&dev->dma_pools);
2859 mutex_init(&dev->mutex);
2860#ifdef CONFIG_PROVE_LOCKING
2861 mutex_init(&dev->lockdep_mutex);
2862#endif
2863 lockdep_set_novalidate_class(&dev->mutex);
2864 spin_lock_init(&dev->devres_lock);
2865 INIT_LIST_HEAD(&dev->devres_head);
2866 device_pm_init(dev);
2867 set_dev_node(dev, -1);
2868#ifdef CONFIG_GENERIC_MSI_IRQ
2869 raw_spin_lock_init(&dev->msi_lock);
2870 INIT_LIST_HEAD(&dev->msi_list);
2871#endif
2872 INIT_LIST_HEAD(&dev->links.consumers);
2873 INIT_LIST_HEAD(&dev->links.suppliers);
2874 INIT_LIST_HEAD(&dev->links.defer_sync);
2875 dev->links.status = DL_DEV_NO_DRIVER;
2876#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
2877 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
2878 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
2879 dev->dma_coherent = dma_default_coherent;
2880#endif
2881}
2882EXPORT_SYMBOL_GPL(device_initialize);
2883
2884struct kobject *virtual_device_parent(struct device *dev)
2885{
2886 static struct kobject *virtual_dir = NULL;
2887
2888 if (!virtual_dir)
2889 virtual_dir = kobject_create_and_add("virtual",
2890 &devices_kset->kobj);
2891
2892 return virtual_dir;
2893}
2894
2895struct class_dir {
2896 struct kobject kobj;
2897 struct class *class;
2898};
2899
2900#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2901
2902static void class_dir_release(struct kobject *kobj)
2903{
2904 struct class_dir *dir = to_class_dir(kobj);
2905 kfree(dir);
2906}
2907
2908static const
2909struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
2910{
2911 struct class_dir *dir = to_class_dir(kobj);
2912 return dir->class->ns_type;
2913}
2914
2915static struct kobj_type class_dir_ktype = {
2916 .release = class_dir_release,
2917 .sysfs_ops = &kobj_sysfs_ops,
2918 .child_ns_type = class_dir_child_ns_type
2919};
2920
2921static struct kobject *
2922class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
2923{
2924 struct class_dir *dir;
2925 int retval;
2926
2927 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
2928 if (!dir)
2929 return ERR_PTR(-ENOMEM);
2930
2931 dir->class = class;
2932 kobject_init(&dir->kobj, &class_dir_ktype);
2933
2934 dir->kobj.kset = &class->p->glue_dirs;
2935
2936 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
2937 if (retval < 0) {
2938 kobject_put(&dir->kobj);
2939 return ERR_PTR(retval);
2940 }
2941 return &dir->kobj;
2942}
2943
2944static DEFINE_MUTEX(gdp_mutex);
2945
2946static struct kobject *get_device_parent(struct device *dev,
2947 struct device *parent)
2948{
2949 if (dev->class) {
2950 struct kobject *kobj = NULL;
2951 struct kobject *parent_kobj;
2952 struct kobject *k;
2953
2954#ifdef CONFIG_BLOCK
2955 /* block disks show up in /sys/block */
2956 if (sysfs_deprecated && dev->class == &block_class) {
2957 if (parent && parent->class == &block_class)
2958 return &parent->kobj;
2959 return &block_class.p->subsys.kobj;
2960 }
2961#endif
2962
2963 /*
2964 * If we have no parent, we live in "virtual".
2965 * Class-devices with a non class-device as parent, live
2966 * in a "glue" directory to prevent namespace collisions.
2967 */
2968 if (parent == NULL)
2969 parent_kobj = virtual_device_parent(dev);
2970 else if (parent->class && !dev->class->ns_type)
2971 return &parent->kobj;
2972 else
2973 parent_kobj = &parent->kobj;
2974
2975 mutex_lock(&gdp_mutex);
2976
2977 /* find our class-directory at the parent and reference it */
2978 spin_lock(&dev->class->p->glue_dirs.list_lock);
2979 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
2980 if (k->parent == parent_kobj) {
2981 kobj = kobject_get(k);
2982 break;
2983 }
2984 spin_unlock(&dev->class->p->glue_dirs.list_lock);
2985 if (kobj) {
2986 mutex_unlock(&gdp_mutex);
2987 return kobj;
2988 }
2989
2990 /* or create a new class-directory at the parent device */
2991 k = class_dir_create_and_add(dev->class, parent_kobj);
2992 /* do not emit an uevent for this simple "glue" directory */
2993 mutex_unlock(&gdp_mutex);
2994 return k;
2995 }
2996
2997 /* subsystems can specify a default root directory for their devices */
2998 if (!parent && dev->bus && dev->bus->dev_root)
2999 return &dev->bus->dev_root->kobj;
3000
3001 if (parent)
3002 return &parent->kobj;
3003 return NULL;
3004}
3005
3006static inline bool live_in_glue_dir(struct kobject *kobj,
3007 struct device *dev)
3008{
3009 if (!kobj || !dev->class ||
3010 kobj->kset != &dev->class->p->glue_dirs)
3011 return false;
3012 return true;
3013}
3014
3015static inline struct kobject *get_glue_dir(struct device *dev)
3016{
3017 return dev->kobj.parent;
3018}
3019
3020/*
3021 * make sure cleaning up dir as the last step, we need to make
3022 * sure .release handler of kobject is run with holding the
3023 * global lock
3024 */
3025static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3026{
3027 unsigned int ref;
3028
3029 /* see if we live in a "glue" directory */
3030 if (!live_in_glue_dir(glue_dir, dev))
3031 return;
3032
3033 mutex_lock(&gdp_mutex);
3034 /**
3035 * There is a race condition between removing glue directory
3036 * and adding a new device under the glue directory.
3037 *
3038 * CPU1: CPU2:
3039 *
3040 * device_add()
3041 * get_device_parent()
3042 * class_dir_create_and_add()
3043 * kobject_add_internal()
3044 * create_dir() // create glue_dir
3045 *
3046 * device_add()
3047 * get_device_parent()
3048 * kobject_get() // get glue_dir
3049 *
3050 * device_del()
3051 * cleanup_glue_dir()
3052 * kobject_del(glue_dir)
3053 *
3054 * kobject_add()
3055 * kobject_add_internal()
3056 * create_dir() // in glue_dir
3057 * sysfs_create_dir_ns()
3058 * kernfs_create_dir_ns(sd)
3059 *
3060 * sysfs_remove_dir() // glue_dir->sd=NULL
3061 * sysfs_put() // free glue_dir->sd
3062 *
3063 * // sd is freed
3064 * kernfs_new_node(sd)
3065 * kernfs_get(glue_dir)
3066 * kernfs_add_one()
3067 * kernfs_put()
3068 *
3069 * Before CPU1 remove last child device under glue dir, if CPU2 add
3070 * a new device under glue dir, the glue_dir kobject reference count
3071 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3072 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3073 * and sysfs_put(). This result in glue_dir->sd is freed.
3074 *
3075 * Then the CPU2 will see a stale "empty" but still potentially used
3076 * glue dir around in kernfs_new_node().
3077 *
3078 * In order to avoid this happening, we also should make sure that
3079 * kernfs_node for glue_dir is released in CPU1 only when refcount
3080 * for glue_dir kobj is 1.
3081 */
3082 ref = kref_read(&glue_dir->kref);
3083 if (!kobject_has_children(glue_dir) && !--ref)
3084 kobject_del(glue_dir);
3085 kobject_put(glue_dir);
3086 mutex_unlock(&gdp_mutex);
3087}
3088
3089static int device_add_class_symlinks(struct device *dev)
3090{
3091 struct device_node *of_node = dev_of_node(dev);
3092 int error;
3093
3094 if (of_node) {
3095 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3096 if (error)
3097 dev_warn(dev, "Error %d creating of_node link\n",error);
3098 /* An error here doesn't warrant bringing down the device */
3099 }
3100
3101 if (!dev->class)
3102 return 0;
3103
3104 error = sysfs_create_link(&dev->kobj,
3105 &dev->class->p->subsys.kobj,
3106 "subsystem");
3107 if (error)
3108 goto out_devnode;
3109
3110 if (dev->parent && device_is_not_partition(dev)) {
3111 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3112 "device");
3113 if (error)
3114 goto out_subsys;
3115 }
3116
3117#ifdef CONFIG_BLOCK
3118 /* /sys/block has directories and does not need symlinks */
3119 if (sysfs_deprecated && dev->class == &block_class)
3120 return 0;
3121#endif
3122
3123 /* link in the class directory pointing to the device */
3124 error = sysfs_create_link(&dev->class->p->subsys.kobj,
3125 &dev->kobj, dev_name(dev));
3126 if (error)
3127 goto out_device;
3128
3129 return 0;
3130
3131out_device:
3132 sysfs_remove_link(&dev->kobj, "device");
3133
3134out_subsys:
3135 sysfs_remove_link(&dev->kobj, "subsystem");
3136out_devnode:
3137 sysfs_remove_link(&dev->kobj, "of_node");
3138 return error;
3139}
3140
3141static void device_remove_class_symlinks(struct device *dev)
3142{
3143 if (dev_of_node(dev))
3144 sysfs_remove_link(&dev->kobj, "of_node");
3145
3146 if (!dev->class)
3147 return;
3148
3149 if (dev->parent && device_is_not_partition(dev))
3150 sysfs_remove_link(&dev->kobj, "device");
3151 sysfs_remove_link(&dev->kobj, "subsystem");
3152#ifdef CONFIG_BLOCK
3153 if (sysfs_deprecated && dev->class == &block_class)
3154 return;
3155#endif
3156 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
3157}
3158
3159/**
3160 * dev_set_name - set a device name
3161 * @dev: device
3162 * @fmt: format string for the device's name
3163 */
3164int dev_set_name(struct device *dev, const char *fmt, ...)
3165{
3166 va_list vargs;
3167 int err;
3168
3169 va_start(vargs, fmt);
3170 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3171 va_end(vargs);
3172 return err;
3173}
3174EXPORT_SYMBOL_GPL(dev_set_name);
3175
3176/**
3177 * device_to_dev_kobj - select a /sys/dev/ directory for the device
3178 * @dev: device
3179 *
3180 * By default we select char/ for new entries. Setting class->dev_obj
3181 * to NULL prevents an entry from being created. class->dev_kobj must
3182 * be set (or cleared) before any devices are registered to the class
3183 * otherwise device_create_sys_dev_entry() and
3184 * device_remove_sys_dev_entry() will disagree about the presence of
3185 * the link.
3186 */
3187static struct kobject *device_to_dev_kobj(struct device *dev)
3188{
3189 struct kobject *kobj;
3190
3191 if (dev->class)
3192 kobj = dev->class->dev_kobj;
3193 else
3194 kobj = sysfs_dev_char_kobj;
3195
3196 return kobj;
3197}
3198
3199static int device_create_sys_dev_entry(struct device *dev)
3200{
3201 struct kobject *kobj = device_to_dev_kobj(dev);
3202 int error = 0;
3203 char devt_str[15];
3204
3205 if (kobj) {
3206 format_dev_t(devt_str, dev->devt);
3207 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3208 }
3209
3210 return error;
3211}
3212
3213static void device_remove_sys_dev_entry(struct device *dev)
3214{
3215 struct kobject *kobj = device_to_dev_kobj(dev);
3216 char devt_str[15];
3217
3218 if (kobj) {
3219 format_dev_t(devt_str, dev->devt);
3220 sysfs_remove_link(kobj, devt_str);
3221 }
3222}
3223
3224static int device_private_init(struct device *dev)
3225{
3226 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3227 if (!dev->p)
3228 return -ENOMEM;
3229 dev->p->device = dev;
3230 klist_init(&dev->p->klist_children, klist_children_get,
3231 klist_children_put);
3232 INIT_LIST_HEAD(&dev->p->deferred_probe);
3233 return 0;
3234}
3235
3236/**
3237 * device_add - add device to device hierarchy.
3238 * @dev: device.
3239 *
3240 * This is part 2 of device_register(), though may be called
3241 * separately _iff_ device_initialize() has been called separately.
3242 *
3243 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3244 * to the global and sibling lists for the device, then
3245 * adds it to the other relevant subsystems of the driver model.
3246 *
3247 * Do not call this routine or device_register() more than once for
3248 * any device structure. The driver model core is not designed to work
3249 * with devices that get unregistered and then spring back to life.
3250 * (Among other things, it's very hard to guarantee that all references
3251 * to the previous incarnation of @dev have been dropped.) Allocate
3252 * and register a fresh new struct device instead.
3253 *
3254 * NOTE: _Never_ directly free @dev after calling this function, even
3255 * if it returned an error! Always use put_device() to give up your
3256 * reference instead.
3257 *
3258 * Rule of thumb is: if device_add() succeeds, you should call
3259 * device_del() when you want to get rid of it. If device_add() has
3260 * *not* succeeded, use *only* put_device() to drop the reference
3261 * count.
3262 */
3263int device_add(struct device *dev)
3264{
3265 struct device *parent;
3266 struct kobject *kobj;
3267 struct class_interface *class_intf;
3268 int error = -EINVAL;
3269 struct kobject *glue_dir = NULL;
3270
3271 dev = get_device(dev);
3272 if (!dev)
3273 goto done;
3274
3275 if (!dev->p) {
3276 error = device_private_init(dev);
3277 if (error)
3278 goto done;
3279 }
3280
3281 /*
3282 * for statically allocated devices, which should all be converted
3283 * some day, we need to initialize the name. We prevent reading back
3284 * the name, and force the use of dev_name()
3285 */
3286 if (dev->init_name) {
3287 dev_set_name(dev, "%s", dev->init_name);
3288 dev->init_name = NULL;
3289 }
3290
3291 /* subsystems can specify simple device enumeration */
3292 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
3293 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3294
3295 if (!dev_name(dev)) {
3296 error = -EINVAL;
3297 goto name_error;
3298 }
3299
3300 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3301
3302 parent = get_device(dev->parent);
3303 kobj = get_device_parent(dev, parent);
3304 if (IS_ERR(kobj)) {
3305 error = PTR_ERR(kobj);
3306 goto parent_error;
3307 }
3308 if (kobj)
3309 dev->kobj.parent = kobj;
3310
3311 /* use parent numa_node */
3312 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3313 set_dev_node(dev, dev_to_node(parent));
3314
3315 /* first, register with generic layer. */
3316 /* we require the name to be set before, and pass NULL */
3317 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3318 if (error) {
3319 glue_dir = get_glue_dir(dev);
3320 goto Error;
3321 }
3322
3323 /* notify platform of device entry */
3324 error = device_platform_notify(dev, KOBJ_ADD);
3325 if (error)
3326 goto platform_error;
3327
3328 error = device_create_file(dev, &dev_attr_uevent);
3329 if (error)
3330 goto attrError;
3331
3332 error = device_add_class_symlinks(dev);
3333 if (error)
3334 goto SymlinkError;
3335 error = device_add_attrs(dev);
3336 if (error)
3337 goto AttrsError;
3338 error = bus_add_device(dev);
3339 if (error)
3340 goto BusError;
3341 error = dpm_sysfs_add(dev);
3342 if (error)
3343 goto DPMError;
3344 device_pm_add(dev);
3345
3346 if (MAJOR(dev->devt)) {
3347 error = device_create_file(dev, &dev_attr_dev);
3348 if (error)
3349 goto DevAttrError;
3350
3351 error = device_create_sys_dev_entry(dev);
3352 if (error)
3353 goto SysEntryError;
3354
3355 devtmpfs_create_node(dev);
3356 }
3357
3358 /* Notify clients of device addition. This call must come
3359 * after dpm_sysfs_add() and before kobject_uevent().
3360 */
3361 if (dev->bus)
3362 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3363 BUS_NOTIFY_ADD_DEVICE, dev);
3364
3365 kobject_uevent(&dev->kobj, KOBJ_ADD);
3366
3367 /*
3368 * Check if any of the other devices (consumers) have been waiting for
3369 * this device (supplier) to be added so that they can create a device
3370 * link to it.
3371 *
3372 * This needs to happen after device_pm_add() because device_link_add()
3373 * requires the supplier be registered before it's called.
3374 *
3375 * But this also needs to happen before bus_probe_device() to make sure
3376 * waiting consumers can link to it before the driver is bound to the
3377 * device and the driver sync_state callback is called for this device.
3378 */
3379 if (dev->fwnode && !dev->fwnode->dev) {
3380 dev->fwnode->dev = dev;
3381 fw_devlink_link_device(dev);
3382 }
3383
3384 bus_probe_device(dev);
3385
3386 /*
3387 * If all driver registration is done and a newly added device doesn't
3388 * match with any driver, don't block its consumers from probing in
3389 * case the consumer device is able to operate without this supplier.
3390 */
3391 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3392 fw_devlink_unblock_consumers(dev);
3393
3394 if (parent)
3395 klist_add_tail(&dev->p->knode_parent,
3396 &parent->p->klist_children);
3397
3398 if (dev->class) {
3399 mutex_lock(&dev->class->p->mutex);
3400 /* tie the class to the device */
3401 klist_add_tail(&dev->p->knode_class,
3402 &dev->class->p->klist_devices);
3403
3404 /* notify any interfaces that the device is here */
3405 list_for_each_entry(class_intf,
3406 &dev->class->p->interfaces, node)
3407 if (class_intf->add_dev)
3408 class_intf->add_dev(dev, class_intf);
3409 mutex_unlock(&dev->class->p->mutex);
3410 }
3411done:
3412 put_device(dev);
3413 return error;
3414 SysEntryError:
3415 if (MAJOR(dev->devt))
3416 device_remove_file(dev, &dev_attr_dev);
3417 DevAttrError:
3418 device_pm_remove(dev);
3419 dpm_sysfs_remove(dev);
3420 DPMError:
3421 bus_remove_device(dev);
3422 BusError:
3423 device_remove_attrs(dev);
3424 AttrsError:
3425 device_remove_class_symlinks(dev);
3426 SymlinkError:
3427 device_remove_file(dev, &dev_attr_uevent);
3428 attrError:
3429 device_platform_notify(dev, KOBJ_REMOVE);
3430platform_error:
3431 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3432 glue_dir = get_glue_dir(dev);
3433 kobject_del(&dev->kobj);
3434 Error:
3435 cleanup_glue_dir(dev, glue_dir);
3436parent_error:
3437 put_device(parent);
3438name_error:
3439 kfree(dev->p);
3440 dev->p = NULL;
3441 goto done;
3442}
3443EXPORT_SYMBOL_GPL(device_add);
3444
3445/**
3446 * device_register - register a device with the system.
3447 * @dev: pointer to the device structure
3448 *
3449 * This happens in two clean steps - initialize the device
3450 * and add it to the system. The two steps can be called
3451 * separately, but this is the easiest and most common.
3452 * I.e. you should only call the two helpers separately if
3453 * have a clearly defined need to use and refcount the device
3454 * before it is added to the hierarchy.
3455 *
3456 * For more information, see the kerneldoc for device_initialize()
3457 * and device_add().
3458 *
3459 * NOTE: _Never_ directly free @dev after calling this function, even
3460 * if it returned an error! Always use put_device() to give up the
3461 * reference initialized in this function instead.
3462 */
3463int device_register(struct device *dev)
3464{
3465 device_initialize(dev);
3466 return device_add(dev);
3467}
3468EXPORT_SYMBOL_GPL(device_register);
3469
3470/**
3471 * get_device - increment reference count for device.
3472 * @dev: device.
3473 *
3474 * This simply forwards the call to kobject_get(), though
3475 * we do take care to provide for the case that we get a NULL
3476 * pointer passed in.
3477 */
3478struct device *get_device(struct device *dev)
3479{
3480 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3481}
3482EXPORT_SYMBOL_GPL(get_device);
3483
3484/**
3485 * put_device - decrement reference count.
3486 * @dev: device in question.
3487 */
3488void put_device(struct device *dev)
3489{
3490 /* might_sleep(); */
3491 if (dev)
3492 kobject_put(&dev->kobj);
3493}
3494EXPORT_SYMBOL_GPL(put_device);
3495
3496bool kill_device(struct device *dev)
3497{
3498 /*
3499 * Require the device lock and set the "dead" flag to guarantee that
3500 * the update behavior is consistent with the other bitfields near
3501 * it and that we cannot have an asynchronous probe routine trying
3502 * to run while we are tearing out the bus/class/sysfs from
3503 * underneath the device.
3504 */
3505 device_lock_assert(dev);
3506
3507 if (dev->p->dead)
3508 return false;
3509 dev->p->dead = true;
3510 return true;
3511}
3512EXPORT_SYMBOL_GPL(kill_device);
3513
3514/**
3515 * device_del - delete device from system.
3516 * @dev: device.
3517 *
3518 * This is the first part of the device unregistration
3519 * sequence. This removes the device from the lists we control
3520 * from here, has it removed from the other driver model
3521 * subsystems it was added to in device_add(), and removes it
3522 * from the kobject hierarchy.
3523 *
3524 * NOTE: this should be called manually _iff_ device_add() was
3525 * also called manually.
3526 */
3527void device_del(struct device *dev)
3528{
3529 struct device *parent = dev->parent;
3530 struct kobject *glue_dir = NULL;
3531 struct class_interface *class_intf;
3532 unsigned int noio_flag;
3533
3534 device_lock(dev);
3535 kill_device(dev);
3536 device_unlock(dev);
3537
3538 if (dev->fwnode && dev->fwnode->dev == dev)
3539 dev->fwnode->dev = NULL;
3540
3541 /* Notify clients of device removal. This call must come
3542 * before dpm_sysfs_remove().
3543 */
3544 noio_flag = memalloc_noio_save();
3545 if (dev->bus)
3546 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3547 BUS_NOTIFY_DEL_DEVICE, dev);
3548
3549 dpm_sysfs_remove(dev);
3550 if (parent)
3551 klist_del(&dev->p->knode_parent);
3552 if (MAJOR(dev->devt)) {
3553 devtmpfs_delete_node(dev);
3554 device_remove_sys_dev_entry(dev);
3555 device_remove_file(dev, &dev_attr_dev);
3556 }
3557 if (dev->class) {
3558 device_remove_class_symlinks(dev);
3559
3560 mutex_lock(&dev->class->p->mutex);
3561 /* notify any interfaces that the device is now gone */
3562 list_for_each_entry(class_intf,
3563 &dev->class->p->interfaces, node)
3564 if (class_intf->remove_dev)
3565 class_intf->remove_dev(dev, class_intf);
3566 /* remove the device from the class list */
3567 klist_del(&dev->p->knode_class);
3568 mutex_unlock(&dev->class->p->mutex);
3569 }
3570 device_remove_file(dev, &dev_attr_uevent);
3571 device_remove_attrs(dev);
3572 bus_remove_device(dev);
3573 device_pm_remove(dev);
3574 driver_deferred_probe_del(dev);
3575 device_platform_notify(dev, KOBJ_REMOVE);
3576 device_remove_properties(dev);
3577 device_links_purge(dev);
3578
3579 if (dev->bus)
3580 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3581 BUS_NOTIFY_REMOVED_DEVICE, dev);
3582 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3583 glue_dir = get_glue_dir(dev);
3584 kobject_del(&dev->kobj);
3585 cleanup_glue_dir(dev, glue_dir);
3586 memalloc_noio_restore(noio_flag);
3587 put_device(parent);
3588}
3589EXPORT_SYMBOL_GPL(device_del);
3590
3591/**
3592 * device_unregister - unregister device from system.
3593 * @dev: device going away.
3594 *
3595 * We do this in two parts, like we do device_register(). First,
3596 * we remove it from all the subsystems with device_del(), then
3597 * we decrement the reference count via put_device(). If that
3598 * is the final reference count, the device will be cleaned up
3599 * via device_release() above. Otherwise, the structure will
3600 * stick around until the final reference to the device is dropped.
3601 */
3602void device_unregister(struct device *dev)
3603{
3604 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3605 device_del(dev);
3606 put_device(dev);
3607}
3608EXPORT_SYMBOL_GPL(device_unregister);
3609
3610static struct device *prev_device(struct klist_iter *i)
3611{
3612 struct klist_node *n = klist_prev(i);
3613 struct device *dev = NULL;
3614 struct device_private *p;
3615
3616 if (n) {
3617 p = to_device_private_parent(n);
3618 dev = p->device;
3619 }
3620 return dev;
3621}
3622
3623static struct device *next_device(struct klist_iter *i)
3624{
3625 struct klist_node *n = klist_next(i);
3626 struct device *dev = NULL;
3627 struct device_private *p;
3628
3629 if (n) {
3630 p = to_device_private_parent(n);
3631 dev = p->device;
3632 }
3633 return dev;
3634}
3635
3636/**
3637 * device_get_devnode - path of device node file
3638 * @dev: device
3639 * @mode: returned file access mode
3640 * @uid: returned file owner
3641 * @gid: returned file group
3642 * @tmp: possibly allocated string
3643 *
3644 * Return the relative path of a possible device node.
3645 * Non-default names may need to allocate a memory to compose
3646 * a name. This memory is returned in tmp and needs to be
3647 * freed by the caller.
3648 */
3649const char *device_get_devnode(struct device *dev,
3650 umode_t *mode, kuid_t *uid, kgid_t *gid,
3651 const char **tmp)
3652{
3653 char *s;
3654
3655 *tmp = NULL;
3656
3657 /* the device type may provide a specific name */
3658 if (dev->type && dev->type->devnode)
3659 *tmp = dev->type->devnode(dev, mode, uid, gid);
3660 if (*tmp)
3661 return *tmp;
3662
3663 /* the class may provide a specific name */
3664 if (dev->class && dev->class->devnode)
3665 *tmp = dev->class->devnode(dev, mode);
3666 if (*tmp)
3667 return *tmp;
3668
3669 /* return name without allocation, tmp == NULL */
3670 if (strchr(dev_name(dev), '!') == NULL)
3671 return dev_name(dev);
3672
3673 /* replace '!' in the name with '/' */
3674 s = kstrdup(dev_name(dev), GFP_KERNEL);
3675 if (!s)
3676 return NULL;
3677 strreplace(s, '!', '/');
3678 return *tmp = s;
3679}
3680
3681/**
3682 * device_for_each_child - device child iterator.
3683 * @parent: parent struct device.
3684 * @fn: function to be called for each device.
3685 * @data: data for the callback.
3686 *
3687 * Iterate over @parent's child devices, and call @fn for each,
3688 * passing it @data.
3689 *
3690 * We check the return of @fn each time. If it returns anything
3691 * other than 0, we break out and return that value.
3692 */
3693int device_for_each_child(struct device *parent, void *data,
3694 int (*fn)(struct device *dev, void *data))
3695{
3696 struct klist_iter i;
3697 struct device *child;
3698 int error = 0;
3699
3700 if (!parent->p)
3701 return 0;
3702
3703 klist_iter_init(&parent->p->klist_children, &i);
3704 while (!error && (child = next_device(&i)))
3705 error = fn(child, data);
3706 klist_iter_exit(&i);
3707 return error;
3708}
3709EXPORT_SYMBOL_GPL(device_for_each_child);
3710
3711/**
3712 * device_for_each_child_reverse - device child iterator in reversed order.
3713 * @parent: parent struct device.
3714 * @fn: function to be called for each device.
3715 * @data: data for the callback.
3716 *
3717 * Iterate over @parent's child devices, and call @fn for each,
3718 * passing it @data.
3719 *
3720 * We check the return of @fn each time. If it returns anything
3721 * other than 0, we break out and return that value.
3722 */
3723int device_for_each_child_reverse(struct device *parent, void *data,
3724 int (*fn)(struct device *dev, void *data))
3725{
3726 struct klist_iter i;
3727 struct device *child;
3728 int error = 0;
3729
3730 if (!parent->p)
3731 return 0;
3732
3733 klist_iter_init(&parent->p->klist_children, &i);
3734 while ((child = prev_device(&i)) && !error)
3735 error = fn(child, data);
3736 klist_iter_exit(&i);
3737 return error;
3738}
3739EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3740
3741/**
3742 * device_find_child - device iterator for locating a particular device.
3743 * @parent: parent struct device
3744 * @match: Callback function to check device
3745 * @data: Data to pass to match function
3746 *
3747 * This is similar to the device_for_each_child() function above, but it
3748 * returns a reference to a device that is 'found' for later use, as
3749 * determined by the @match callback.
3750 *
3751 * The callback should return 0 if the device doesn't match and non-zero
3752 * if it does. If the callback returns non-zero and a reference to the
3753 * current device can be obtained, this function will return to the caller
3754 * and not iterate over any more devices.
3755 *
3756 * NOTE: you will need to drop the reference with put_device() after use.
3757 */
3758struct device *device_find_child(struct device *parent, void *data,
3759 int (*match)(struct device *dev, void *data))
3760{
3761 struct klist_iter i;
3762 struct device *child;
3763
3764 if (!parent)
3765 return NULL;
3766
3767 klist_iter_init(&parent->p->klist_children, &i);
3768 while ((child = next_device(&i)))
3769 if (match(child, data) && get_device(child))
3770 break;
3771 klist_iter_exit(&i);
3772 return child;
3773}
3774EXPORT_SYMBOL_GPL(device_find_child);
3775
3776/**
3777 * device_find_child_by_name - device iterator for locating a child device.
3778 * @parent: parent struct device
3779 * @name: name of the child device
3780 *
3781 * This is similar to the device_find_child() function above, but it
3782 * returns a reference to a device that has the name @name.
3783 *
3784 * NOTE: you will need to drop the reference with put_device() after use.
3785 */
3786struct device *device_find_child_by_name(struct device *parent,
3787 const char *name)
3788{
3789 struct klist_iter i;
3790 struct device *child;
3791
3792 if (!parent)
3793 return NULL;
3794
3795 klist_iter_init(&parent->p->klist_children, &i);
3796 while ((child = next_device(&i)))
3797 if (sysfs_streq(dev_name(child), name) && get_device(child))
3798 break;
3799 klist_iter_exit(&i);
3800 return child;
3801}
3802EXPORT_SYMBOL_GPL(device_find_child_by_name);
3803
3804int __init devices_init(void)
3805{
3806 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3807 if (!devices_kset)
3808 return -ENOMEM;
3809 dev_kobj = kobject_create_and_add("dev", NULL);
3810 if (!dev_kobj)
3811 goto dev_kobj_err;
3812 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3813 if (!sysfs_dev_block_kobj)
3814 goto block_kobj_err;
3815 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3816 if (!sysfs_dev_char_kobj)
3817 goto char_kobj_err;
3818
3819 return 0;
3820
3821 char_kobj_err:
3822 kobject_put(sysfs_dev_block_kobj);
3823 block_kobj_err:
3824 kobject_put(dev_kobj);
3825 dev_kobj_err:
3826 kset_unregister(devices_kset);
3827 return -ENOMEM;
3828}
3829
3830static int device_check_offline(struct device *dev, void *not_used)
3831{
3832 int ret;
3833
3834 ret = device_for_each_child(dev, NULL, device_check_offline);
3835 if (ret)
3836 return ret;
3837
3838 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3839}
3840
3841/**
3842 * device_offline - Prepare the device for hot-removal.
3843 * @dev: Device to be put offline.
3844 *
3845 * Execute the device bus type's .offline() callback, if present, to prepare
3846 * the device for a subsequent hot-removal. If that succeeds, the device must
3847 * not be used until either it is removed or its bus type's .online() callback
3848 * is executed.
3849 *
3850 * Call under device_hotplug_lock.
3851 */
3852int device_offline(struct device *dev)
3853{
3854 int ret;
3855
3856 if (dev->offline_disabled)
3857 return -EPERM;
3858
3859 ret = device_for_each_child(dev, NULL, device_check_offline);
3860 if (ret)
3861 return ret;
3862
3863 device_lock(dev);
3864 if (device_supports_offline(dev)) {
3865 if (dev->offline) {
3866 ret = 1;
3867 } else {
3868 ret = dev->bus->offline(dev);
3869 if (!ret) {
3870 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3871 dev->offline = true;
3872 }
3873 }
3874 }
3875 device_unlock(dev);
3876
3877 return ret;
3878}
3879
3880/**
3881 * device_online - Put the device back online after successful device_offline().
3882 * @dev: Device to be put back online.
3883 *
3884 * If device_offline() has been successfully executed for @dev, but the device
3885 * has not been removed subsequently, execute its bus type's .online() callback
3886 * to indicate that the device can be used again.
3887 *
3888 * Call under device_hotplug_lock.
3889 */
3890int device_online(struct device *dev)
3891{
3892 int ret = 0;
3893
3894 device_lock(dev);
3895 if (device_supports_offline(dev)) {
3896 if (dev->offline) {
3897 ret = dev->bus->online(dev);
3898 if (!ret) {
3899 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
3900 dev->offline = false;
3901 }
3902 } else {
3903 ret = 1;
3904 }
3905 }
3906 device_unlock(dev);
3907
3908 return ret;
3909}
3910
3911struct root_device {
3912 struct device dev;
3913 struct module *owner;
3914};
3915
3916static inline struct root_device *to_root_device(struct device *d)
3917{
3918 return container_of(d, struct root_device, dev);
3919}
3920
3921static void root_device_release(struct device *dev)
3922{
3923 kfree(to_root_device(dev));
3924}
3925
3926/**
3927 * __root_device_register - allocate and register a root device
3928 * @name: root device name
3929 * @owner: owner module of the root device, usually THIS_MODULE
3930 *
3931 * This function allocates a root device and registers it
3932 * using device_register(). In order to free the returned
3933 * device, use root_device_unregister().
3934 *
3935 * Root devices are dummy devices which allow other devices
3936 * to be grouped under /sys/devices. Use this function to
3937 * allocate a root device and then use it as the parent of
3938 * any device which should appear under /sys/devices/{name}
3939 *
3940 * The /sys/devices/{name} directory will also contain a
3941 * 'module' symlink which points to the @owner directory
3942 * in sysfs.
3943 *
3944 * Returns &struct device pointer on success, or ERR_PTR() on error.
3945 *
3946 * Note: You probably want to use root_device_register().
3947 */
3948struct device *__root_device_register(const char *name, struct module *owner)
3949{
3950 struct root_device *root;
3951 int err = -ENOMEM;
3952
3953 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
3954 if (!root)
3955 return ERR_PTR(err);
3956
3957 err = dev_set_name(&root->dev, "%s", name);
3958 if (err) {
3959 kfree(root);
3960 return ERR_PTR(err);
3961 }
3962
3963 root->dev.release = root_device_release;
3964
3965 err = device_register(&root->dev);
3966 if (err) {
3967 put_device(&root->dev);
3968 return ERR_PTR(err);
3969 }
3970
3971#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
3972 if (owner) {
3973 struct module_kobject *mk = &owner->mkobj;
3974
3975 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
3976 if (err) {
3977 device_unregister(&root->dev);
3978 return ERR_PTR(err);
3979 }
3980 root->owner = owner;
3981 }
3982#endif
3983
3984 return &root->dev;
3985}
3986EXPORT_SYMBOL_GPL(__root_device_register);
3987
3988/**
3989 * root_device_unregister - unregister and free a root device
3990 * @dev: device going away
3991 *
3992 * This function unregisters and cleans up a device that was created by
3993 * root_device_register().
3994 */
3995void root_device_unregister(struct device *dev)
3996{
3997 struct root_device *root = to_root_device(dev);
3998
3999 if (root->owner)
4000 sysfs_remove_link(&root->dev.kobj, "module");
4001
4002 device_unregister(dev);
4003}
4004EXPORT_SYMBOL_GPL(root_device_unregister);
4005
4006
4007static void device_create_release(struct device *dev)
4008{
4009 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4010 kfree(dev);
4011}
4012
4013static __printf(6, 0) struct device *
4014device_create_groups_vargs(struct class *class, struct device *parent,
4015 dev_t devt, void *drvdata,
4016 const struct attribute_group **groups,
4017 const char *fmt, va_list args)
4018{
4019 struct device *dev = NULL;
4020 int retval = -ENODEV;
4021
4022 if (class == NULL || IS_ERR(class))
4023 goto error;
4024
4025 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4026 if (!dev) {
4027 retval = -ENOMEM;
4028 goto error;
4029 }
4030
4031 device_initialize(dev);
4032 dev->devt = devt;
4033 dev->class = class;
4034 dev->parent = parent;
4035 dev->groups = groups;
4036 dev->release = device_create_release;
4037 dev_set_drvdata(dev, drvdata);
4038
4039 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4040 if (retval)
4041 goto error;
4042
4043 retval = device_add(dev);
4044 if (retval)
4045 goto error;
4046
4047 return dev;
4048
4049error:
4050 put_device(dev);
4051 return ERR_PTR(retval);
4052}
4053
4054/**
4055 * device_create - creates a device and registers it with sysfs
4056 * @class: pointer to the struct class that this device should be registered to
4057 * @parent: pointer to the parent struct device of this new device, if any
4058 * @devt: the dev_t for the char device to be added
4059 * @drvdata: the data to be added to the device for callbacks
4060 * @fmt: string for the device's name
4061 *
4062 * This function can be used by char device classes. A struct device
4063 * will be created in sysfs, registered to the specified class.
4064 *
4065 * A "dev" file will be created, showing the dev_t for the device, if
4066 * the dev_t is not 0,0.
4067 * If a pointer to a parent struct device is passed in, the newly created
4068 * struct device will be a child of that device in sysfs.
4069 * The pointer to the struct device will be returned from the call.
4070 * Any further sysfs files that might be required can be created using this
4071 * pointer.
4072 *
4073 * Returns &struct device pointer on success, or ERR_PTR() on error.
4074 *
4075 * Note: the struct class passed to this function must have previously
4076 * been created with a call to class_create().
4077 */
4078struct device *device_create(struct class *class, struct device *parent,
4079 dev_t devt, void *drvdata, const char *fmt, ...)
4080{
4081 va_list vargs;
4082 struct device *dev;
4083
4084 va_start(vargs, fmt);
4085 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4086 fmt, vargs);
4087 va_end(vargs);
4088 return dev;
4089}
4090EXPORT_SYMBOL_GPL(device_create);
4091
4092/**
4093 * device_create_with_groups - creates a device and registers it with sysfs
4094 * @class: pointer to the struct class that this device should be registered to
4095 * @parent: pointer to the parent struct device of this new device, if any
4096 * @devt: the dev_t for the char device to be added
4097 * @drvdata: the data to be added to the device for callbacks
4098 * @groups: NULL-terminated list of attribute groups to be created
4099 * @fmt: string for the device's name
4100 *
4101 * This function can be used by char device classes. A struct device
4102 * will be created in sysfs, registered to the specified class.
4103 * Additional attributes specified in the groups parameter will also
4104 * be created automatically.
4105 *
4106 * A "dev" file will be created, showing the dev_t for the device, if
4107 * the dev_t is not 0,0.
4108 * If a pointer to a parent struct device is passed in, the newly created
4109 * struct device will be a child of that device in sysfs.
4110 * The pointer to the struct device will be returned from the call.
4111 * Any further sysfs files that might be required can be created using this
4112 * pointer.
4113 *
4114 * Returns &struct device pointer on success, or ERR_PTR() on error.
4115 *
4116 * Note: the struct class passed to this function must have previously
4117 * been created with a call to class_create().
4118 */
4119struct device *device_create_with_groups(struct class *class,
4120 struct device *parent, dev_t devt,
4121 void *drvdata,
4122 const struct attribute_group **groups,
4123 const char *fmt, ...)
4124{
4125 va_list vargs;
4126 struct device *dev;
4127
4128 va_start(vargs, fmt);
4129 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4130 fmt, vargs);
4131 va_end(vargs);
4132 return dev;
4133}
4134EXPORT_SYMBOL_GPL(device_create_with_groups);
4135
4136/**
4137 * device_destroy - removes a device that was created with device_create()
4138 * @class: pointer to the struct class that this device was registered with
4139 * @devt: the dev_t of the device that was previously registered
4140 *
4141 * This call unregisters and cleans up a device that was created with a
4142 * call to device_create().
4143 */
4144void device_destroy(struct class *class, dev_t devt)
4145{
4146 struct device *dev;
4147
4148 dev = class_find_device_by_devt(class, devt);
4149 if (dev) {
4150 put_device(dev);
4151 device_unregister(dev);
4152 }
4153}
4154EXPORT_SYMBOL_GPL(device_destroy);
4155
4156/**
4157 * device_rename - renames a device
4158 * @dev: the pointer to the struct device to be renamed
4159 * @new_name: the new name of the device
4160 *
4161 * It is the responsibility of the caller to provide mutual
4162 * exclusion between two different calls of device_rename
4163 * on the same device to ensure that new_name is valid and
4164 * won't conflict with other devices.
4165 *
4166 * Note: Don't call this function. Currently, the networking layer calls this
4167 * function, but that will change. The following text from Kay Sievers offers
4168 * some insight:
4169 *
4170 * Renaming devices is racy at many levels, symlinks and other stuff are not
4171 * replaced atomically, and you get a "move" uevent, but it's not easy to
4172 * connect the event to the old and new device. Device nodes are not renamed at
4173 * all, there isn't even support for that in the kernel now.
4174 *
4175 * In the meantime, during renaming, your target name might be taken by another
4176 * driver, creating conflicts. Or the old name is taken directly after you
4177 * renamed it -- then you get events for the same DEVPATH, before you even see
4178 * the "move" event. It's just a mess, and nothing new should ever rely on
4179 * kernel device renaming. Besides that, it's not even implemented now for
4180 * other things than (driver-core wise very simple) network devices.
4181 *
4182 * We are currently about to change network renaming in udev to completely
4183 * disallow renaming of devices in the same namespace as the kernel uses,
4184 * because we can't solve the problems properly, that arise with swapping names
4185 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
4186 * be allowed to some other name than eth[0-9]*, for the aforementioned
4187 * reasons.
4188 *
4189 * Make up a "real" name in the driver before you register anything, or add
4190 * some other attributes for userspace to find the device, or use udev to add
4191 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4192 * don't even want to get into that and try to implement the missing pieces in
4193 * the core. We really have other pieces to fix in the driver core mess. :)
4194 */
4195int device_rename(struct device *dev, const char *new_name)
4196{
4197 struct kobject *kobj = &dev->kobj;
4198 char *old_device_name = NULL;
4199 int error;
4200
4201 dev = get_device(dev);
4202 if (!dev)
4203 return -EINVAL;
4204
4205 dev_dbg(dev, "renaming to %s\n", new_name);
4206
4207 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4208 if (!old_device_name) {
4209 error = -ENOMEM;
4210 goto out;
4211 }
4212
4213 if (dev->class) {
4214 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
4215 kobj, old_device_name,
4216 new_name, kobject_namespace(kobj));
4217 if (error)
4218 goto out;
4219 }
4220
4221 error = kobject_rename(kobj, new_name);
4222 if (error)
4223 goto out;
4224
4225out:
4226 put_device(dev);
4227
4228 kfree(old_device_name);
4229
4230 return error;
4231}
4232EXPORT_SYMBOL_GPL(device_rename);
4233
4234static int device_move_class_links(struct device *dev,
4235 struct device *old_parent,
4236 struct device *new_parent)
4237{
4238 int error = 0;
4239
4240 if (old_parent)
4241 sysfs_remove_link(&dev->kobj, "device");
4242 if (new_parent)
4243 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4244 "device");
4245 return error;
4246}
4247
4248/**
4249 * device_move - moves a device to a new parent
4250 * @dev: the pointer to the struct device to be moved
4251 * @new_parent: the new parent of the device (can be NULL)
4252 * @dpm_order: how to reorder the dpm_list
4253 */
4254int device_move(struct device *dev, struct device *new_parent,
4255 enum dpm_order dpm_order)
4256{
4257 int error;
4258 struct device *old_parent;
4259 struct kobject *new_parent_kobj;
4260
4261 dev = get_device(dev);
4262 if (!dev)
4263 return -EINVAL;
4264
4265 device_pm_lock();
4266 new_parent = get_device(new_parent);
4267 new_parent_kobj = get_device_parent(dev, new_parent);
4268 if (IS_ERR(new_parent_kobj)) {
4269 error = PTR_ERR(new_parent_kobj);
4270 put_device(new_parent);
4271 goto out;
4272 }
4273
4274 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4275 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4276 error = kobject_move(&dev->kobj, new_parent_kobj);
4277 if (error) {
4278 cleanup_glue_dir(dev, new_parent_kobj);
4279 put_device(new_parent);
4280 goto out;
4281 }
4282 old_parent = dev->parent;
4283 dev->parent = new_parent;
4284 if (old_parent)
4285 klist_remove(&dev->p->knode_parent);
4286 if (new_parent) {
4287 klist_add_tail(&dev->p->knode_parent,
4288 &new_parent->p->klist_children);
4289 set_dev_node(dev, dev_to_node(new_parent));
4290 }
4291
4292 if (dev->class) {
4293 error = device_move_class_links(dev, old_parent, new_parent);
4294 if (error) {
4295 /* We ignore errors on cleanup since we're hosed anyway... */
4296 device_move_class_links(dev, new_parent, old_parent);
4297 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4298 if (new_parent)
4299 klist_remove(&dev->p->knode_parent);
4300 dev->parent = old_parent;
4301 if (old_parent) {
4302 klist_add_tail(&dev->p->knode_parent,
4303 &old_parent->p->klist_children);
4304 set_dev_node(dev, dev_to_node(old_parent));
4305 }
4306 }
4307 cleanup_glue_dir(dev, new_parent_kobj);
4308 put_device(new_parent);
4309 goto out;
4310 }
4311 }
4312 switch (dpm_order) {
4313 case DPM_ORDER_NONE:
4314 break;
4315 case DPM_ORDER_DEV_AFTER_PARENT:
4316 device_pm_move_after(dev, new_parent);
4317 devices_kset_move_after(dev, new_parent);
4318 break;
4319 case DPM_ORDER_PARENT_BEFORE_DEV:
4320 device_pm_move_before(new_parent, dev);
4321 devices_kset_move_before(new_parent, dev);
4322 break;
4323 case DPM_ORDER_DEV_LAST:
4324 device_pm_move_last(dev);
4325 devices_kset_move_last(dev);
4326 break;
4327 }
4328
4329 put_device(old_parent);
4330out:
4331 device_pm_unlock();
4332 put_device(dev);
4333 return error;
4334}
4335EXPORT_SYMBOL_GPL(device_move);
4336
4337static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4338 kgid_t kgid)
4339{
4340 struct kobject *kobj = &dev->kobj;
4341 struct class *class = dev->class;
4342 const struct device_type *type = dev->type;
4343 int error;
4344
4345 if (class) {
4346 /*
4347 * Change the device groups of the device class for @dev to
4348 * @kuid/@kgid.
4349 */
4350 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4351 kgid);
4352 if (error)
4353 return error;
4354 }
4355
4356 if (type) {
4357 /*
4358 * Change the device groups of the device type for @dev to
4359 * @kuid/@kgid.
4360 */
4361 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4362 kgid);
4363 if (error)
4364 return error;
4365 }
4366
4367 /* Change the device groups of @dev to @kuid/@kgid. */
4368 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4369 if (error)
4370 return error;
4371
4372 if (device_supports_offline(dev) && !dev->offline_disabled) {
4373 /* Change online device attributes of @dev to @kuid/@kgid. */
4374 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4375 kuid, kgid);
4376 if (error)
4377 return error;
4378 }
4379
4380 return 0;
4381}
4382
4383/**
4384 * device_change_owner - change the owner of an existing device.
4385 * @dev: device.
4386 * @kuid: new owner's kuid
4387 * @kgid: new owner's kgid
4388 *
4389 * This changes the owner of @dev and its corresponding sysfs entries to
4390 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4391 * core.
4392 *
4393 * Returns 0 on success or error code on failure.
4394 */
4395int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4396{
4397 int error;
4398 struct kobject *kobj = &dev->kobj;
4399
4400 dev = get_device(dev);
4401 if (!dev)
4402 return -EINVAL;
4403
4404 /*
4405 * Change the kobject and the default attributes and groups of the
4406 * ktype associated with it to @kuid/@kgid.
4407 */
4408 error = sysfs_change_owner(kobj, kuid, kgid);
4409 if (error)
4410 goto out;
4411
4412 /*
4413 * Change the uevent file for @dev to the new owner. The uevent file
4414 * was created in a separate step when @dev got added and we mirror
4415 * that step here.
4416 */
4417 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4418 kgid);
4419 if (error)
4420 goto out;
4421
4422 /*
4423 * Change the device groups, the device groups associated with the
4424 * device class, and the groups associated with the device type of @dev
4425 * to @kuid/@kgid.
4426 */
4427 error = device_attrs_change_owner(dev, kuid, kgid);
4428 if (error)
4429 goto out;
4430
4431 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4432 if (error)
4433 goto out;
4434
4435#ifdef CONFIG_BLOCK
4436 if (sysfs_deprecated && dev->class == &block_class)
4437 goto out;
4438#endif
4439
4440 /*
4441 * Change the owner of the symlink located in the class directory of
4442 * the device class associated with @dev which points to the actual
4443 * directory entry for @dev to @kuid/@kgid. This ensures that the
4444 * symlink shows the same permissions as its target.
4445 */
4446 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
4447 dev_name(dev), kuid, kgid);
4448 if (error)
4449 goto out;
4450
4451out:
4452 put_device(dev);
4453 return error;
4454}
4455EXPORT_SYMBOL_GPL(device_change_owner);
4456
4457/**
4458 * device_shutdown - call ->shutdown() on each device to shutdown.
4459 */
4460void device_shutdown(void)
4461{
4462 struct device *dev, *parent;
4463
4464 wait_for_device_probe();
4465 device_block_probing();
4466
4467 cpufreq_suspend();
4468
4469 spin_lock(&devices_kset->list_lock);
4470 /*
4471 * Walk the devices list backward, shutting down each in turn.
4472 * Beware that device unplug events may also start pulling
4473 * devices offline, even as the system is shutting down.
4474 */
4475 while (!list_empty(&devices_kset->list)) {
4476 dev = list_entry(devices_kset->list.prev, struct device,
4477 kobj.entry);
4478
4479 /*
4480 * hold reference count of device's parent to
4481 * prevent it from being freed because parent's
4482 * lock is to be held
4483 */
4484 parent = get_device(dev->parent);
4485 get_device(dev);
4486 /*
4487 * Make sure the device is off the kset list, in the
4488 * event that dev->*->shutdown() doesn't remove it.
4489 */
4490 list_del_init(&dev->kobj.entry);
4491 spin_unlock(&devices_kset->list_lock);
4492
4493 /* hold lock to avoid race with probe/release */
4494 if (parent)
4495 device_lock(parent);
4496 device_lock(dev);
4497
4498 /* Don't allow any more runtime suspends */
4499 pm_runtime_get_noresume(dev);
4500 pm_runtime_barrier(dev);
4501
4502 if (dev->class && dev->class->shutdown_pre) {
4503 if (initcall_debug)
4504 dev_info(dev, "shutdown_pre\n");
4505 dev->class->shutdown_pre(dev);
4506 }
4507 if (dev->bus && dev->bus->shutdown) {
4508 if (initcall_debug)
4509 dev_info(dev, "shutdown\n");
4510 dev->bus->shutdown(dev);
4511 } else if (dev->driver && dev->driver->shutdown) {
4512 if (initcall_debug)
4513 dev_info(dev, "shutdown\n");
4514 dev->driver->shutdown(dev);
4515 }
4516
4517 device_unlock(dev);
4518 if (parent)
4519 device_unlock(parent);
4520
4521 put_device(dev);
4522 put_device(parent);
4523
4524 spin_lock(&devices_kset->list_lock);
4525 }
4526 spin_unlock(&devices_kset->list_lock);
4527}
4528
4529/*
4530 * Device logging functions
4531 */
4532
4533#ifdef CONFIG_PRINTK
4534static void
4535set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4536{
4537 const char *subsys;
4538
4539 memset(dev_info, 0, sizeof(*dev_info));
4540
4541 if (dev->class)
4542 subsys = dev->class->name;
4543 else if (dev->bus)
4544 subsys = dev->bus->name;
4545 else
4546 return;
4547
4548 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4549
4550 /*
4551 * Add device identifier DEVICE=:
4552 * b12:8 block dev_t
4553 * c127:3 char dev_t
4554 * n8 netdev ifindex
4555 * +sound:card0 subsystem:devname
4556 */
4557 if (MAJOR(dev->devt)) {
4558 char c;
4559
4560 if (strcmp(subsys, "block") == 0)
4561 c = 'b';
4562 else
4563 c = 'c';
4564
4565 snprintf(dev_info->device, sizeof(dev_info->device),
4566 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4567 } else if (strcmp(subsys, "net") == 0) {
4568 struct net_device *net = to_net_dev(dev);
4569
4570 snprintf(dev_info->device, sizeof(dev_info->device),
4571 "n%u", net->ifindex);
4572 } else {
4573 snprintf(dev_info->device, sizeof(dev_info->device),
4574 "+%s:%s", subsys, dev_name(dev));
4575 }
4576}
4577
4578int dev_vprintk_emit(int level, const struct device *dev,
4579 const char *fmt, va_list args)
4580{
4581 struct dev_printk_info dev_info;
4582
4583 set_dev_info(dev, &dev_info);
4584
4585 return vprintk_emit(0, level, &dev_info, fmt, args);
4586}
4587EXPORT_SYMBOL(dev_vprintk_emit);
4588
4589int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4590{
4591 va_list args;
4592 int r;
4593
4594 va_start(args, fmt);
4595
4596 r = dev_vprintk_emit(level, dev, fmt, args);
4597
4598 va_end(args);
4599
4600 return r;
4601}
4602EXPORT_SYMBOL(dev_printk_emit);
4603
4604static void __dev_printk(const char *level, const struct device *dev,
4605 struct va_format *vaf)
4606{
4607 if (dev)
4608 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4609 dev_driver_string(dev), dev_name(dev), vaf);
4610 else
4611 printk("%s(NULL device *): %pV", level, vaf);
4612}
4613
4614void dev_printk(const char *level, const struct device *dev,
4615 const char *fmt, ...)
4616{
4617 struct va_format vaf;
4618 va_list args;
4619
4620 va_start(args, fmt);
4621
4622 vaf.fmt = fmt;
4623 vaf.va = &args;
4624
4625 __dev_printk(level, dev, &vaf);
4626
4627 va_end(args);
4628}
4629EXPORT_SYMBOL(dev_printk);
4630
4631#define define_dev_printk_level(func, kern_level) \
4632void func(const struct device *dev, const char *fmt, ...) \
4633{ \
4634 struct va_format vaf; \
4635 va_list args; \
4636 \
4637 va_start(args, fmt); \
4638 \
4639 vaf.fmt = fmt; \
4640 vaf.va = &args; \
4641 \
4642 __dev_printk(kern_level, dev, &vaf); \
4643 \
4644 va_end(args); \
4645} \
4646EXPORT_SYMBOL(func);
4647
4648define_dev_printk_level(_dev_emerg, KERN_EMERG);
4649define_dev_printk_level(_dev_alert, KERN_ALERT);
4650define_dev_printk_level(_dev_crit, KERN_CRIT);
4651define_dev_printk_level(_dev_err, KERN_ERR);
4652define_dev_printk_level(_dev_warn, KERN_WARNING);
4653define_dev_printk_level(_dev_notice, KERN_NOTICE);
4654define_dev_printk_level(_dev_info, KERN_INFO);
4655
4656#endif
4657
4658/**
4659 * dev_err_probe - probe error check and log helper
4660 * @dev: the pointer to the struct device
4661 * @err: error value to test
4662 * @fmt: printf-style format string
4663 * @...: arguments as specified in the format string
4664 *
4665 * This helper implements common pattern present in probe functions for error
4666 * checking: print debug or error message depending if the error value is
4667 * -EPROBE_DEFER and propagate error upwards.
4668 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4669 * checked later by reading devices_deferred debugfs attribute.
4670 * It replaces code sequence::
4671 *
4672 * if (err != -EPROBE_DEFER)
4673 * dev_err(dev, ...);
4674 * else
4675 * dev_dbg(dev, ...);
4676 * return err;
4677 *
4678 * with::
4679 *
4680 * return dev_err_probe(dev, err, ...);
4681 *
4682 * Returns @err.
4683 *
4684 */
4685int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4686{
4687 struct va_format vaf;
4688 va_list args;
4689
4690 va_start(args, fmt);
4691 vaf.fmt = fmt;
4692 vaf.va = &args;
4693
4694 if (err != -EPROBE_DEFER) {
4695 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4696 } else {
4697 device_set_deferred_probe_reason(dev, &vaf);
4698 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4699 }
4700
4701 va_end(args);
4702
4703 return err;
4704}
4705EXPORT_SYMBOL_GPL(dev_err_probe);
4706
4707static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4708{
4709 return fwnode && !IS_ERR(fwnode->secondary);
4710}
4711
4712/**
4713 * set_primary_fwnode - Change the primary firmware node of a given device.
4714 * @dev: Device to handle.
4715 * @fwnode: New primary firmware node of the device.
4716 *
4717 * Set the device's firmware node pointer to @fwnode, but if a secondary
4718 * firmware node of the device is present, preserve it.
4719 *
4720 * Valid fwnode cases are:
4721 * - primary --> secondary --> -ENODEV
4722 * - primary --> NULL
4723 * - secondary --> -ENODEV
4724 * - NULL
4725 */
4726void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4727{
4728 struct device *parent = dev->parent;
4729 struct fwnode_handle *fn = dev->fwnode;
4730
4731 if (fwnode) {
4732 if (fwnode_is_primary(fn))
4733 fn = fn->secondary;
4734
4735 if (fn) {
4736 WARN_ON(fwnode->secondary);
4737 fwnode->secondary = fn;
4738 }
4739 dev->fwnode = fwnode;
4740 } else {
4741 if (fwnode_is_primary(fn)) {
4742 dev->fwnode = fn->secondary;
4743 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
4744 if (!(parent && fn == parent->fwnode))
4745 fn->secondary = NULL;
4746 } else {
4747 dev->fwnode = NULL;
4748 }
4749 }
4750}
4751EXPORT_SYMBOL_GPL(set_primary_fwnode);
4752
4753/**
4754 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4755 * @dev: Device to handle.
4756 * @fwnode: New secondary firmware node of the device.
4757 *
4758 * If a primary firmware node of the device is present, set its secondary
4759 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4760 * @fwnode.
4761 */
4762void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4763{
4764 if (fwnode)
4765 fwnode->secondary = ERR_PTR(-ENODEV);
4766
4767 if (fwnode_is_primary(dev->fwnode))
4768 dev->fwnode->secondary = fwnode;
4769 else
4770 dev->fwnode = fwnode;
4771}
4772EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4773
4774/**
4775 * device_set_of_node_from_dev - reuse device-tree node of another device
4776 * @dev: device whose device-tree node is being set
4777 * @dev2: device whose device-tree node is being reused
4778 *
4779 * Takes another reference to the new device-tree node after first dropping
4780 * any reference held to the old node.
4781 */
4782void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4783{
4784 of_node_put(dev->of_node);
4785 dev->of_node = of_node_get(dev2->of_node);
4786 dev->of_node_reused = true;
4787}
4788EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4789
4790void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
4791{
4792 dev->fwnode = fwnode;
4793 dev->of_node = to_of_node(fwnode);
4794}
4795EXPORT_SYMBOL_GPL(device_set_node);
4796
4797int device_match_name(struct device *dev, const void *name)
4798{
4799 return sysfs_streq(dev_name(dev), name);
4800}
4801EXPORT_SYMBOL_GPL(device_match_name);
4802
4803int device_match_of_node(struct device *dev, const void *np)
4804{
4805 return dev->of_node == np;
4806}
4807EXPORT_SYMBOL_GPL(device_match_of_node);
4808
4809int device_match_fwnode(struct device *dev, const void *fwnode)
4810{
4811 return dev_fwnode(dev) == fwnode;
4812}
4813EXPORT_SYMBOL_GPL(device_match_fwnode);
4814
4815int device_match_devt(struct device *dev, const void *pdevt)
4816{
4817 return dev->devt == *(dev_t *)pdevt;
4818}
4819EXPORT_SYMBOL_GPL(device_match_devt);
4820
4821int device_match_acpi_dev(struct device *dev, const void *adev)
4822{
4823 return ACPI_COMPANION(dev) == adev;
4824}
4825EXPORT_SYMBOL(device_match_acpi_dev);
4826
4827int device_match_any(struct device *dev, const void *unused)
4828{
4829 return 1;
4830}
4831EXPORT_SYMBOL_GPL(device_match_any);