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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/kstrtox.h>
18#include <linux/module.h>
19#include <linux/slab.h>
20#include <linux/kdev_t.h>
21#include <linux/notifier.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/blkdev.h>
25#include <linux/mutex.h>
26#include <linux/pm_runtime.h>
27#include <linux/netdevice.h>
28#include <linux/sched/signal.h>
29#include <linux/sched/mm.h>
30#include <linux/string_helpers.h>
31#include <linux/swiotlb.h>
32#include <linux/sysfs.h>
33#include <linux/dma-map-ops.h> /* for dma_default_coherent */
34
35#include "base.h"
36#include "physical_location.h"
37#include "power/power.h"
38
39/* Device links support. */
40static LIST_HEAD(deferred_sync);
41static unsigned int defer_sync_state_count = 1;
42static DEFINE_MUTEX(fwnode_link_lock);
43static bool fw_devlink_is_permissive(void);
44static void __fw_devlink_link_to_consumers(struct device *dev);
45static bool fw_devlink_drv_reg_done;
46static bool fw_devlink_best_effort;
47static struct workqueue_struct *device_link_wq;
48
49/**
50 * __fwnode_link_add - Create a link between two fwnode_handles.
51 * @con: Consumer end of the link.
52 * @sup: Supplier end of the link.
53 * @flags: Link flags.
54 *
55 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
56 * represents the detail that the firmware lists @sup fwnode as supplying a
57 * resource to @con.
58 *
59 * The driver core will use the fwnode link to create a device link between the
60 * two device objects corresponding to @con and @sup when they are created. The
61 * driver core will automatically delete the fwnode link between @con and @sup
62 * after doing that.
63 *
64 * Attempts to create duplicate links between the same pair of fwnode handles
65 * are ignored and there is no reference counting.
66 */
67static int __fwnode_link_add(struct fwnode_handle *con,
68 struct fwnode_handle *sup, u8 flags)
69{
70 struct fwnode_link *link;
71
72 list_for_each_entry(link, &sup->consumers, s_hook)
73 if (link->consumer == con) {
74 link->flags |= flags;
75 return 0;
76 }
77
78 link = kzalloc(sizeof(*link), GFP_KERNEL);
79 if (!link)
80 return -ENOMEM;
81
82 link->supplier = sup;
83 INIT_LIST_HEAD(&link->s_hook);
84 link->consumer = con;
85 INIT_LIST_HEAD(&link->c_hook);
86 link->flags = flags;
87
88 list_add(&link->s_hook, &sup->consumers);
89 list_add(&link->c_hook, &con->suppliers);
90 pr_debug("%pfwf Linked as a fwnode consumer to %pfwf\n",
91 con, sup);
92
93 return 0;
94}
95
96int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup,
97 u8 flags)
98{
99 int ret;
100
101 mutex_lock(&fwnode_link_lock);
102 ret = __fwnode_link_add(con, sup, flags);
103 mutex_unlock(&fwnode_link_lock);
104 return ret;
105}
106
107/**
108 * __fwnode_link_del - Delete a link between two fwnode_handles.
109 * @link: the fwnode_link to be deleted
110 *
111 * The fwnode_link_lock needs to be held when this function is called.
112 */
113static void __fwnode_link_del(struct fwnode_link *link)
114{
115 pr_debug("%pfwf Dropping the fwnode link to %pfwf\n",
116 link->consumer, link->supplier);
117 list_del(&link->s_hook);
118 list_del(&link->c_hook);
119 kfree(link);
120}
121
122/**
123 * __fwnode_link_cycle - Mark a fwnode link as being part of a cycle.
124 * @link: the fwnode_link to be marked
125 *
126 * The fwnode_link_lock needs to be held when this function is called.
127 */
128static void __fwnode_link_cycle(struct fwnode_link *link)
129{
130 pr_debug("%pfwf: cycle: depends on %pfwf\n",
131 link->consumer, link->supplier);
132 link->flags |= FWLINK_FLAG_CYCLE;
133}
134
135/**
136 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
137 * @fwnode: fwnode whose supplier links need to be deleted
138 *
139 * Deletes all supplier links connecting directly to @fwnode.
140 */
141static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
142{
143 struct fwnode_link *link, *tmp;
144
145 mutex_lock(&fwnode_link_lock);
146 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
147 __fwnode_link_del(link);
148 mutex_unlock(&fwnode_link_lock);
149}
150
151/**
152 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
153 * @fwnode: fwnode whose consumer links need to be deleted
154 *
155 * Deletes all consumer links connecting directly to @fwnode.
156 */
157static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
158{
159 struct fwnode_link *link, *tmp;
160
161 mutex_lock(&fwnode_link_lock);
162 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
163 __fwnode_link_del(link);
164 mutex_unlock(&fwnode_link_lock);
165}
166
167/**
168 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
169 * @fwnode: fwnode whose links needs to be deleted
170 *
171 * Deletes all links connecting directly to a fwnode.
172 */
173void fwnode_links_purge(struct fwnode_handle *fwnode)
174{
175 fwnode_links_purge_suppliers(fwnode);
176 fwnode_links_purge_consumers(fwnode);
177}
178
179void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
180{
181 struct fwnode_handle *child;
182
183 /* Don't purge consumer links of an added child */
184 if (fwnode->dev)
185 return;
186
187 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
188 fwnode_links_purge_consumers(fwnode);
189
190 fwnode_for_each_available_child_node(fwnode, child)
191 fw_devlink_purge_absent_suppliers(child);
192}
193EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
194
195/**
196 * __fwnode_links_move_consumers - Move consumer from @from to @to fwnode_handle
197 * @from: move consumers away from this fwnode
198 * @to: move consumers to this fwnode
199 *
200 * Move all consumer links from @from fwnode to @to fwnode.
201 */
202static void __fwnode_links_move_consumers(struct fwnode_handle *from,
203 struct fwnode_handle *to)
204{
205 struct fwnode_link *link, *tmp;
206
207 list_for_each_entry_safe(link, tmp, &from->consumers, s_hook) {
208 __fwnode_link_add(link->consumer, to, link->flags);
209 __fwnode_link_del(link);
210 }
211}
212
213/**
214 * __fw_devlink_pickup_dangling_consumers - Pick up dangling consumers
215 * @fwnode: fwnode from which to pick up dangling consumers
216 * @new_sup: fwnode of new supplier
217 *
218 * If the @fwnode has a corresponding struct device and the device supports
219 * probing (that is, added to a bus), then we want to let fw_devlink create
220 * MANAGED device links to this device, so leave @fwnode and its descendant's
221 * fwnode links alone.
222 *
223 * Otherwise, move its consumers to the new supplier @new_sup.
224 */
225static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode,
226 struct fwnode_handle *new_sup)
227{
228 struct fwnode_handle *child;
229
230 if (fwnode->dev && fwnode->dev->bus)
231 return;
232
233 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
234 __fwnode_links_move_consumers(fwnode, new_sup);
235
236 fwnode_for_each_available_child_node(fwnode, child)
237 __fw_devlink_pickup_dangling_consumers(child, new_sup);
238}
239
240static DEFINE_MUTEX(device_links_lock);
241DEFINE_STATIC_SRCU(device_links_srcu);
242
243static inline void device_links_write_lock(void)
244{
245 mutex_lock(&device_links_lock);
246}
247
248static inline void device_links_write_unlock(void)
249{
250 mutex_unlock(&device_links_lock);
251}
252
253int device_links_read_lock(void) __acquires(&device_links_srcu)
254{
255 return srcu_read_lock(&device_links_srcu);
256}
257
258void device_links_read_unlock(int idx) __releases(&device_links_srcu)
259{
260 srcu_read_unlock(&device_links_srcu, idx);
261}
262
263int device_links_read_lock_held(void)
264{
265 return srcu_read_lock_held(&device_links_srcu);
266}
267
268static void device_link_synchronize_removal(void)
269{
270 synchronize_srcu(&device_links_srcu);
271}
272
273static void device_link_remove_from_lists(struct device_link *link)
274{
275 list_del_rcu(&link->s_node);
276 list_del_rcu(&link->c_node);
277}
278
279static bool device_is_ancestor(struct device *dev, struct device *target)
280{
281 while (target->parent) {
282 target = target->parent;
283 if (dev == target)
284 return true;
285 }
286 return false;
287}
288
289#define DL_MARKER_FLAGS (DL_FLAG_INFERRED | \
290 DL_FLAG_CYCLE | \
291 DL_FLAG_MANAGED)
292static inline bool device_link_flag_is_sync_state_only(u32 flags)
293{
294 return (flags & ~DL_MARKER_FLAGS) == DL_FLAG_SYNC_STATE_ONLY;
295}
296
297/**
298 * device_is_dependent - Check if one device depends on another one
299 * @dev: Device to check dependencies for.
300 * @target: Device to check against.
301 *
302 * Check if @target depends on @dev or any device dependent on it (its child or
303 * its consumer etc). Return 1 if that is the case or 0 otherwise.
304 */
305static int device_is_dependent(struct device *dev, void *target)
306{
307 struct device_link *link;
308 int ret;
309
310 /*
311 * The "ancestors" check is needed to catch the case when the target
312 * device has not been completely initialized yet and it is still
313 * missing from the list of children of its parent device.
314 */
315 if (dev == target || device_is_ancestor(dev, target))
316 return 1;
317
318 ret = device_for_each_child(dev, target, device_is_dependent);
319 if (ret)
320 return ret;
321
322 list_for_each_entry(link, &dev->links.consumers, s_node) {
323 if (device_link_flag_is_sync_state_only(link->flags))
324 continue;
325
326 if (link->consumer == target)
327 return 1;
328
329 ret = device_is_dependent(link->consumer, target);
330 if (ret)
331 break;
332 }
333 return ret;
334}
335
336static void device_link_init_status(struct device_link *link,
337 struct device *consumer,
338 struct device *supplier)
339{
340 switch (supplier->links.status) {
341 case DL_DEV_PROBING:
342 switch (consumer->links.status) {
343 case DL_DEV_PROBING:
344 /*
345 * A consumer driver can create a link to a supplier
346 * that has not completed its probing yet as long as it
347 * knows that the supplier is already functional (for
348 * example, it has just acquired some resources from the
349 * supplier).
350 */
351 link->status = DL_STATE_CONSUMER_PROBE;
352 break;
353 default:
354 link->status = DL_STATE_DORMANT;
355 break;
356 }
357 break;
358 case DL_DEV_DRIVER_BOUND:
359 switch (consumer->links.status) {
360 case DL_DEV_PROBING:
361 link->status = DL_STATE_CONSUMER_PROBE;
362 break;
363 case DL_DEV_DRIVER_BOUND:
364 link->status = DL_STATE_ACTIVE;
365 break;
366 default:
367 link->status = DL_STATE_AVAILABLE;
368 break;
369 }
370 break;
371 case DL_DEV_UNBINDING:
372 link->status = DL_STATE_SUPPLIER_UNBIND;
373 break;
374 default:
375 link->status = DL_STATE_DORMANT;
376 break;
377 }
378}
379
380static int device_reorder_to_tail(struct device *dev, void *not_used)
381{
382 struct device_link *link;
383
384 /*
385 * Devices that have not been registered yet will be put to the ends
386 * of the lists during the registration, so skip them here.
387 */
388 if (device_is_registered(dev))
389 devices_kset_move_last(dev);
390
391 if (device_pm_initialized(dev))
392 device_pm_move_last(dev);
393
394 device_for_each_child(dev, NULL, device_reorder_to_tail);
395 list_for_each_entry(link, &dev->links.consumers, s_node) {
396 if (device_link_flag_is_sync_state_only(link->flags))
397 continue;
398 device_reorder_to_tail(link->consumer, NULL);
399 }
400
401 return 0;
402}
403
404/**
405 * device_pm_move_to_tail - Move set of devices to the end of device lists
406 * @dev: Device to move
407 *
408 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
409 *
410 * It moves the @dev along with all of its children and all of its consumers
411 * to the ends of the device_kset and dpm_list, recursively.
412 */
413void device_pm_move_to_tail(struct device *dev)
414{
415 int idx;
416
417 idx = device_links_read_lock();
418 device_pm_lock();
419 device_reorder_to_tail(dev, NULL);
420 device_pm_unlock();
421 device_links_read_unlock(idx);
422}
423
424#define to_devlink(dev) container_of((dev), struct device_link, link_dev)
425
426static ssize_t status_show(struct device *dev,
427 struct device_attribute *attr, char *buf)
428{
429 const char *output;
430
431 switch (to_devlink(dev)->status) {
432 case DL_STATE_NONE:
433 output = "not tracked";
434 break;
435 case DL_STATE_DORMANT:
436 output = "dormant";
437 break;
438 case DL_STATE_AVAILABLE:
439 output = "available";
440 break;
441 case DL_STATE_CONSUMER_PROBE:
442 output = "consumer probing";
443 break;
444 case DL_STATE_ACTIVE:
445 output = "active";
446 break;
447 case DL_STATE_SUPPLIER_UNBIND:
448 output = "supplier unbinding";
449 break;
450 default:
451 output = "unknown";
452 break;
453 }
454
455 return sysfs_emit(buf, "%s\n", output);
456}
457static DEVICE_ATTR_RO(status);
458
459static ssize_t auto_remove_on_show(struct device *dev,
460 struct device_attribute *attr, char *buf)
461{
462 struct device_link *link = to_devlink(dev);
463 const char *output;
464
465 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
466 output = "supplier unbind";
467 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
468 output = "consumer unbind";
469 else
470 output = "never";
471
472 return sysfs_emit(buf, "%s\n", output);
473}
474static DEVICE_ATTR_RO(auto_remove_on);
475
476static ssize_t runtime_pm_show(struct device *dev,
477 struct device_attribute *attr, char *buf)
478{
479 struct device_link *link = to_devlink(dev);
480
481 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
482}
483static DEVICE_ATTR_RO(runtime_pm);
484
485static ssize_t sync_state_only_show(struct device *dev,
486 struct device_attribute *attr, char *buf)
487{
488 struct device_link *link = to_devlink(dev);
489
490 return sysfs_emit(buf, "%d\n",
491 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
492}
493static DEVICE_ATTR_RO(sync_state_only);
494
495static struct attribute *devlink_attrs[] = {
496 &dev_attr_status.attr,
497 &dev_attr_auto_remove_on.attr,
498 &dev_attr_runtime_pm.attr,
499 &dev_attr_sync_state_only.attr,
500 NULL,
501};
502ATTRIBUTE_GROUPS(devlink);
503
504static void device_link_release_fn(struct work_struct *work)
505{
506 struct device_link *link = container_of(work, struct device_link, rm_work);
507
508 /* Ensure that all references to the link object have been dropped. */
509 device_link_synchronize_removal();
510
511 pm_runtime_release_supplier(link);
512 /*
513 * If supplier_preactivated is set, the link has been dropped between
514 * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
515 * in __driver_probe_device(). In that case, drop the supplier's
516 * PM-runtime usage counter to remove the reference taken by
517 * pm_runtime_get_suppliers().
518 */
519 if (link->supplier_preactivated)
520 pm_runtime_put_noidle(link->supplier);
521
522 pm_request_idle(link->supplier);
523
524 put_device(link->consumer);
525 put_device(link->supplier);
526 kfree(link);
527}
528
529static void devlink_dev_release(struct device *dev)
530{
531 struct device_link *link = to_devlink(dev);
532
533 INIT_WORK(&link->rm_work, device_link_release_fn);
534 /*
535 * It may take a while to complete this work because of the SRCU
536 * synchronization in device_link_release_fn() and if the consumer or
537 * supplier devices get deleted when it runs, so put it into the
538 * dedicated workqueue.
539 */
540 queue_work(device_link_wq, &link->rm_work);
541}
542
543/**
544 * device_link_wait_removal - Wait for ongoing devlink removal jobs to terminate
545 */
546void device_link_wait_removal(void)
547{
548 /*
549 * devlink removal jobs are queued in the dedicated work queue.
550 * To be sure that all removal jobs are terminated, ensure that any
551 * scheduled work has run to completion.
552 */
553 flush_workqueue(device_link_wq);
554}
555EXPORT_SYMBOL_GPL(device_link_wait_removal);
556
557static struct class devlink_class = {
558 .name = "devlink",
559 .dev_groups = devlink_groups,
560 .dev_release = devlink_dev_release,
561};
562
563static int devlink_add_symlinks(struct device *dev)
564{
565 int ret;
566 size_t len;
567 struct device_link *link = to_devlink(dev);
568 struct device *sup = link->supplier;
569 struct device *con = link->consumer;
570 char *buf;
571
572 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
573 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
574 len += strlen(":");
575 len += strlen("supplier:") + 1;
576 buf = kzalloc(len, GFP_KERNEL);
577 if (!buf)
578 return -ENOMEM;
579
580 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
581 if (ret)
582 goto out;
583
584 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
585 if (ret)
586 goto err_con;
587
588 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
589 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
590 if (ret)
591 goto err_con_dev;
592
593 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
594 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
595 if (ret)
596 goto err_sup_dev;
597
598 goto out;
599
600err_sup_dev:
601 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
602 sysfs_remove_link(&sup->kobj, buf);
603err_con_dev:
604 sysfs_remove_link(&link->link_dev.kobj, "consumer");
605err_con:
606 sysfs_remove_link(&link->link_dev.kobj, "supplier");
607out:
608 kfree(buf);
609 return ret;
610}
611
612static void devlink_remove_symlinks(struct device *dev)
613{
614 struct device_link *link = to_devlink(dev);
615 size_t len;
616 struct device *sup = link->supplier;
617 struct device *con = link->consumer;
618 char *buf;
619
620 sysfs_remove_link(&link->link_dev.kobj, "consumer");
621 sysfs_remove_link(&link->link_dev.kobj, "supplier");
622
623 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
624 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
625 len += strlen(":");
626 len += strlen("supplier:") + 1;
627 buf = kzalloc(len, GFP_KERNEL);
628 if (!buf) {
629 WARN(1, "Unable to properly free device link symlinks!\n");
630 return;
631 }
632
633 if (device_is_registered(con)) {
634 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
635 sysfs_remove_link(&con->kobj, buf);
636 }
637 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
638 sysfs_remove_link(&sup->kobj, buf);
639 kfree(buf);
640}
641
642static struct class_interface devlink_class_intf = {
643 .class = &devlink_class,
644 .add_dev = devlink_add_symlinks,
645 .remove_dev = devlink_remove_symlinks,
646};
647
648static int __init devlink_class_init(void)
649{
650 int ret;
651
652 ret = class_register(&devlink_class);
653 if (ret)
654 return ret;
655
656 ret = class_interface_register(&devlink_class_intf);
657 if (ret)
658 class_unregister(&devlink_class);
659
660 return ret;
661}
662postcore_initcall(devlink_class_init);
663
664#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
665 DL_FLAG_AUTOREMOVE_SUPPLIER | \
666 DL_FLAG_AUTOPROBE_CONSUMER | \
667 DL_FLAG_SYNC_STATE_ONLY | \
668 DL_FLAG_INFERRED | \
669 DL_FLAG_CYCLE)
670
671#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
672 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
673
674/**
675 * device_link_add - Create a link between two devices.
676 * @consumer: Consumer end of the link.
677 * @supplier: Supplier end of the link.
678 * @flags: Link flags.
679 *
680 * The caller is responsible for the proper synchronization of the link creation
681 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
682 * runtime PM framework to take the link into account. Second, if the
683 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
684 * be forced into the active meta state and reference-counted upon the creation
685 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
686 * ignored.
687 *
688 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
689 * expected to release the link returned by it directly with the help of either
690 * device_link_del() or device_link_remove().
691 *
692 * If that flag is not set, however, the caller of this function is handing the
693 * management of the link over to the driver core entirely and its return value
694 * can only be used to check whether or not the link is present. In that case,
695 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
696 * flags can be used to indicate to the driver core when the link can be safely
697 * deleted. Namely, setting one of them in @flags indicates to the driver core
698 * that the link is not going to be used (by the given caller of this function)
699 * after unbinding the consumer or supplier driver, respectively, from its
700 * device, so the link can be deleted at that point. If none of them is set,
701 * the link will be maintained until one of the devices pointed to by it (either
702 * the consumer or the supplier) is unregistered.
703 *
704 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
705 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
706 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
707 * be used to request the driver core to automatically probe for a consumer
708 * driver after successfully binding a driver to the supplier device.
709 *
710 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
711 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
712 * the same time is invalid and will cause NULL to be returned upfront.
713 * However, if a device link between the given @consumer and @supplier pair
714 * exists already when this function is called for them, the existing link will
715 * be returned regardless of its current type and status (the link's flags may
716 * be modified then). The caller of this function is then expected to treat
717 * the link as though it has just been created, so (in particular) if
718 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
719 * explicitly when not needed any more (as stated above).
720 *
721 * A side effect of the link creation is re-ordering of dpm_list and the
722 * devices_kset list by moving the consumer device and all devices depending
723 * on it to the ends of these lists (that does not happen to devices that have
724 * not been registered when this function is called).
725 *
726 * The supplier device is required to be registered when this function is called
727 * and NULL will be returned if that is not the case. The consumer device need
728 * not be registered, however.
729 */
730struct device_link *device_link_add(struct device *consumer,
731 struct device *supplier, u32 flags)
732{
733 struct device_link *link;
734
735 if (!consumer || !supplier || consumer == supplier ||
736 flags & ~DL_ADD_VALID_FLAGS ||
737 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
738 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
739 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
740 DL_FLAG_AUTOREMOVE_SUPPLIER)))
741 return NULL;
742
743 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
744 if (pm_runtime_get_sync(supplier) < 0) {
745 pm_runtime_put_noidle(supplier);
746 return NULL;
747 }
748 }
749
750 if (!(flags & DL_FLAG_STATELESS))
751 flags |= DL_FLAG_MANAGED;
752
753 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
754 !device_link_flag_is_sync_state_only(flags))
755 return NULL;
756
757 device_links_write_lock();
758 device_pm_lock();
759
760 /*
761 * If the supplier has not been fully registered yet or there is a
762 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
763 * the supplier already in the graph, return NULL. If the link is a
764 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
765 * because it only affects sync_state() callbacks.
766 */
767 if (!device_pm_initialized(supplier)
768 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
769 device_is_dependent(consumer, supplier))) {
770 link = NULL;
771 goto out;
772 }
773
774 /*
775 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
776 * So, only create it if the consumer hasn't probed yet.
777 */
778 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
779 consumer->links.status != DL_DEV_NO_DRIVER &&
780 consumer->links.status != DL_DEV_PROBING) {
781 link = NULL;
782 goto out;
783 }
784
785 /*
786 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
787 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
788 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
789 */
790 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
791 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
792
793 list_for_each_entry(link, &supplier->links.consumers, s_node) {
794 if (link->consumer != consumer)
795 continue;
796
797 if (link->flags & DL_FLAG_INFERRED &&
798 !(flags & DL_FLAG_INFERRED))
799 link->flags &= ~DL_FLAG_INFERRED;
800
801 if (flags & DL_FLAG_PM_RUNTIME) {
802 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
803 pm_runtime_new_link(consumer);
804 link->flags |= DL_FLAG_PM_RUNTIME;
805 }
806 if (flags & DL_FLAG_RPM_ACTIVE)
807 refcount_inc(&link->rpm_active);
808 }
809
810 if (flags & DL_FLAG_STATELESS) {
811 kref_get(&link->kref);
812 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
813 !(link->flags & DL_FLAG_STATELESS)) {
814 link->flags |= DL_FLAG_STATELESS;
815 goto reorder;
816 } else {
817 link->flags |= DL_FLAG_STATELESS;
818 goto out;
819 }
820 }
821
822 /*
823 * If the life time of the link following from the new flags is
824 * longer than indicated by the flags of the existing link,
825 * update the existing link to stay around longer.
826 */
827 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
828 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
829 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
830 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
831 }
832 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
833 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
834 DL_FLAG_AUTOREMOVE_SUPPLIER);
835 }
836 if (!(link->flags & DL_FLAG_MANAGED)) {
837 kref_get(&link->kref);
838 link->flags |= DL_FLAG_MANAGED;
839 device_link_init_status(link, consumer, supplier);
840 }
841 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
842 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
843 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
844 goto reorder;
845 }
846
847 goto out;
848 }
849
850 link = kzalloc(sizeof(*link), GFP_KERNEL);
851 if (!link)
852 goto out;
853
854 refcount_set(&link->rpm_active, 1);
855
856 get_device(supplier);
857 link->supplier = supplier;
858 INIT_LIST_HEAD(&link->s_node);
859 get_device(consumer);
860 link->consumer = consumer;
861 INIT_LIST_HEAD(&link->c_node);
862 link->flags = flags;
863 kref_init(&link->kref);
864
865 link->link_dev.class = &devlink_class;
866 device_set_pm_not_required(&link->link_dev);
867 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
868 dev_bus_name(supplier), dev_name(supplier),
869 dev_bus_name(consumer), dev_name(consumer));
870 if (device_register(&link->link_dev)) {
871 put_device(&link->link_dev);
872 link = NULL;
873 goto out;
874 }
875
876 if (flags & DL_FLAG_PM_RUNTIME) {
877 if (flags & DL_FLAG_RPM_ACTIVE)
878 refcount_inc(&link->rpm_active);
879
880 pm_runtime_new_link(consumer);
881 }
882
883 /* Determine the initial link state. */
884 if (flags & DL_FLAG_STATELESS)
885 link->status = DL_STATE_NONE;
886 else
887 device_link_init_status(link, consumer, supplier);
888
889 /*
890 * Some callers expect the link creation during consumer driver probe to
891 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
892 */
893 if (link->status == DL_STATE_CONSUMER_PROBE &&
894 flags & DL_FLAG_PM_RUNTIME)
895 pm_runtime_resume(supplier);
896
897 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
898 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
899
900 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
901 dev_dbg(consumer,
902 "Linked as a sync state only consumer to %s\n",
903 dev_name(supplier));
904 goto out;
905 }
906
907reorder:
908 /*
909 * Move the consumer and all of the devices depending on it to the end
910 * of dpm_list and the devices_kset list.
911 *
912 * It is necessary to hold dpm_list locked throughout all that or else
913 * we may end up suspending with a wrong ordering of it.
914 */
915 device_reorder_to_tail(consumer, NULL);
916
917 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
918
919out:
920 device_pm_unlock();
921 device_links_write_unlock();
922
923 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
924 pm_runtime_put(supplier);
925
926 return link;
927}
928EXPORT_SYMBOL_GPL(device_link_add);
929
930static void __device_link_del(struct kref *kref)
931{
932 struct device_link *link = container_of(kref, struct device_link, kref);
933
934 dev_dbg(link->consumer, "Dropping the link to %s\n",
935 dev_name(link->supplier));
936
937 pm_runtime_drop_link(link);
938
939 device_link_remove_from_lists(link);
940 device_unregister(&link->link_dev);
941}
942
943static void device_link_put_kref(struct device_link *link)
944{
945 if (link->flags & DL_FLAG_STATELESS)
946 kref_put(&link->kref, __device_link_del);
947 else if (!device_is_registered(link->consumer))
948 __device_link_del(&link->kref);
949 else
950 WARN(1, "Unable to drop a managed device link reference\n");
951}
952
953/**
954 * device_link_del - Delete a stateless link between two devices.
955 * @link: Device link to delete.
956 *
957 * The caller must ensure proper synchronization of this function with runtime
958 * PM. If the link was added multiple times, it needs to be deleted as often.
959 * Care is required for hotplugged devices: Their links are purged on removal
960 * and calling device_link_del() is then no longer allowed.
961 */
962void device_link_del(struct device_link *link)
963{
964 device_links_write_lock();
965 device_link_put_kref(link);
966 device_links_write_unlock();
967}
968EXPORT_SYMBOL_GPL(device_link_del);
969
970/**
971 * device_link_remove - Delete a stateless link between two devices.
972 * @consumer: Consumer end of the link.
973 * @supplier: Supplier end of the link.
974 *
975 * The caller must ensure proper synchronization of this function with runtime
976 * PM.
977 */
978void device_link_remove(void *consumer, struct device *supplier)
979{
980 struct device_link *link;
981
982 if (WARN_ON(consumer == supplier))
983 return;
984
985 device_links_write_lock();
986
987 list_for_each_entry(link, &supplier->links.consumers, s_node) {
988 if (link->consumer == consumer) {
989 device_link_put_kref(link);
990 break;
991 }
992 }
993
994 device_links_write_unlock();
995}
996EXPORT_SYMBOL_GPL(device_link_remove);
997
998static void device_links_missing_supplier(struct device *dev)
999{
1000 struct device_link *link;
1001
1002 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1003 if (link->status != DL_STATE_CONSUMER_PROBE)
1004 continue;
1005
1006 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1007 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1008 } else {
1009 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1010 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1011 }
1012 }
1013}
1014
1015static bool dev_is_best_effort(struct device *dev)
1016{
1017 return (fw_devlink_best_effort && dev->can_match) ||
1018 (dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
1019}
1020
1021static struct fwnode_handle *fwnode_links_check_suppliers(
1022 struct fwnode_handle *fwnode)
1023{
1024 struct fwnode_link *link;
1025
1026 if (!fwnode || fw_devlink_is_permissive())
1027 return NULL;
1028
1029 list_for_each_entry(link, &fwnode->suppliers, c_hook)
1030 if (!(link->flags &
1031 (FWLINK_FLAG_CYCLE | FWLINK_FLAG_IGNORE)))
1032 return link->supplier;
1033
1034 return NULL;
1035}
1036
1037/**
1038 * device_links_check_suppliers - Check presence of supplier drivers.
1039 * @dev: Consumer device.
1040 *
1041 * Check links from this device to any suppliers. Walk the list of the device's
1042 * links to suppliers and see if all of them are available. If not, simply
1043 * return -EPROBE_DEFER.
1044 *
1045 * We need to guarantee that the supplier will not go away after the check has
1046 * been positive here. It only can go away in __device_release_driver() and
1047 * that function checks the device's links to consumers. This means we need to
1048 * mark the link as "consumer probe in progress" to make the supplier removal
1049 * wait for us to complete (or bad things may happen).
1050 *
1051 * Links without the DL_FLAG_MANAGED flag set are ignored.
1052 */
1053int device_links_check_suppliers(struct device *dev)
1054{
1055 struct device_link *link;
1056 int ret = 0, fwnode_ret = 0;
1057 struct fwnode_handle *sup_fw;
1058
1059 /*
1060 * Device waiting for supplier to become available is not allowed to
1061 * probe.
1062 */
1063 mutex_lock(&fwnode_link_lock);
1064 sup_fw = fwnode_links_check_suppliers(dev->fwnode);
1065 if (sup_fw) {
1066 if (!dev_is_best_effort(dev)) {
1067 fwnode_ret = -EPROBE_DEFER;
1068 dev_err_probe(dev, -EPROBE_DEFER,
1069 "wait for supplier %pfwf\n", sup_fw);
1070 } else {
1071 fwnode_ret = -EAGAIN;
1072 }
1073 }
1074 mutex_unlock(&fwnode_link_lock);
1075 if (fwnode_ret == -EPROBE_DEFER)
1076 return fwnode_ret;
1077
1078 device_links_write_lock();
1079
1080 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1081 if (!(link->flags & DL_FLAG_MANAGED))
1082 continue;
1083
1084 if (link->status != DL_STATE_AVAILABLE &&
1085 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1086
1087 if (dev_is_best_effort(dev) &&
1088 link->flags & DL_FLAG_INFERRED &&
1089 !link->supplier->can_match) {
1090 ret = -EAGAIN;
1091 continue;
1092 }
1093
1094 device_links_missing_supplier(dev);
1095 dev_err_probe(dev, -EPROBE_DEFER,
1096 "supplier %s not ready\n",
1097 dev_name(link->supplier));
1098 ret = -EPROBE_DEFER;
1099 break;
1100 }
1101 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1102 }
1103 dev->links.status = DL_DEV_PROBING;
1104
1105 device_links_write_unlock();
1106
1107 return ret ? ret : fwnode_ret;
1108}
1109
1110/**
1111 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1112 * @dev: Device to call sync_state() on
1113 * @list: List head to queue the @dev on
1114 *
1115 * Queues a device for a sync_state() callback when the device links write lock
1116 * isn't held. This allows the sync_state() execution flow to use device links
1117 * APIs. The caller must ensure this function is called with
1118 * device_links_write_lock() held.
1119 *
1120 * This function does a get_device() to make sure the device is not freed while
1121 * on this list.
1122 *
1123 * So the caller must also ensure that device_links_flush_sync_list() is called
1124 * as soon as the caller releases device_links_write_lock(). This is necessary
1125 * to make sure the sync_state() is called in a timely fashion and the
1126 * put_device() is called on this device.
1127 */
1128static void __device_links_queue_sync_state(struct device *dev,
1129 struct list_head *list)
1130{
1131 struct device_link *link;
1132
1133 if (!dev_has_sync_state(dev))
1134 return;
1135 if (dev->state_synced)
1136 return;
1137
1138 list_for_each_entry(link, &dev->links.consumers, s_node) {
1139 if (!(link->flags & DL_FLAG_MANAGED))
1140 continue;
1141 if (link->status != DL_STATE_ACTIVE)
1142 return;
1143 }
1144
1145 /*
1146 * Set the flag here to avoid adding the same device to a list more
1147 * than once. This can happen if new consumers get added to the device
1148 * and probed before the list is flushed.
1149 */
1150 dev->state_synced = true;
1151
1152 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1153 return;
1154
1155 get_device(dev);
1156 list_add_tail(&dev->links.defer_sync, list);
1157}
1158
1159/**
1160 * device_links_flush_sync_list - Call sync_state() on a list of devices
1161 * @list: List of devices to call sync_state() on
1162 * @dont_lock_dev: Device for which lock is already held by the caller
1163 *
1164 * Calls sync_state() on all the devices that have been queued for it. This
1165 * function is used in conjunction with __device_links_queue_sync_state(). The
1166 * @dont_lock_dev parameter is useful when this function is called from a
1167 * context where a device lock is already held.
1168 */
1169static void device_links_flush_sync_list(struct list_head *list,
1170 struct device *dont_lock_dev)
1171{
1172 struct device *dev, *tmp;
1173
1174 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1175 list_del_init(&dev->links.defer_sync);
1176
1177 if (dev != dont_lock_dev)
1178 device_lock(dev);
1179
1180 dev_sync_state(dev);
1181
1182 if (dev != dont_lock_dev)
1183 device_unlock(dev);
1184
1185 put_device(dev);
1186 }
1187}
1188
1189void device_links_supplier_sync_state_pause(void)
1190{
1191 device_links_write_lock();
1192 defer_sync_state_count++;
1193 device_links_write_unlock();
1194}
1195
1196void device_links_supplier_sync_state_resume(void)
1197{
1198 struct device *dev, *tmp;
1199 LIST_HEAD(sync_list);
1200
1201 device_links_write_lock();
1202 if (!defer_sync_state_count) {
1203 WARN(true, "Unmatched sync_state pause/resume!");
1204 goto out;
1205 }
1206 defer_sync_state_count--;
1207 if (defer_sync_state_count)
1208 goto out;
1209
1210 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1211 /*
1212 * Delete from deferred_sync list before queuing it to
1213 * sync_list because defer_sync is used for both lists.
1214 */
1215 list_del_init(&dev->links.defer_sync);
1216 __device_links_queue_sync_state(dev, &sync_list);
1217 }
1218out:
1219 device_links_write_unlock();
1220
1221 device_links_flush_sync_list(&sync_list, NULL);
1222}
1223
1224static int sync_state_resume_initcall(void)
1225{
1226 device_links_supplier_sync_state_resume();
1227 return 0;
1228}
1229late_initcall(sync_state_resume_initcall);
1230
1231static void __device_links_supplier_defer_sync(struct device *sup)
1232{
1233 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1234 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1235}
1236
1237static void device_link_drop_managed(struct device_link *link)
1238{
1239 link->flags &= ~DL_FLAG_MANAGED;
1240 WRITE_ONCE(link->status, DL_STATE_NONE);
1241 kref_put(&link->kref, __device_link_del);
1242}
1243
1244static ssize_t waiting_for_supplier_show(struct device *dev,
1245 struct device_attribute *attr,
1246 char *buf)
1247{
1248 bool val;
1249
1250 device_lock(dev);
1251 mutex_lock(&fwnode_link_lock);
1252 val = !!fwnode_links_check_suppliers(dev->fwnode);
1253 mutex_unlock(&fwnode_link_lock);
1254 device_unlock(dev);
1255 return sysfs_emit(buf, "%u\n", val);
1256}
1257static DEVICE_ATTR_RO(waiting_for_supplier);
1258
1259/**
1260 * device_links_force_bind - Prepares device to be force bound
1261 * @dev: Consumer device.
1262 *
1263 * device_bind_driver() force binds a device to a driver without calling any
1264 * driver probe functions. So the consumer really isn't going to wait for any
1265 * supplier before it's bound to the driver. We still want the device link
1266 * states to be sensible when this happens.
1267 *
1268 * In preparation for device_bind_driver(), this function goes through each
1269 * supplier device links and checks if the supplier is bound. If it is, then
1270 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1271 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1272 */
1273void device_links_force_bind(struct device *dev)
1274{
1275 struct device_link *link, *ln;
1276
1277 device_links_write_lock();
1278
1279 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1280 if (!(link->flags & DL_FLAG_MANAGED))
1281 continue;
1282
1283 if (link->status != DL_STATE_AVAILABLE) {
1284 device_link_drop_managed(link);
1285 continue;
1286 }
1287 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1288 }
1289 dev->links.status = DL_DEV_PROBING;
1290
1291 device_links_write_unlock();
1292}
1293
1294/**
1295 * device_links_driver_bound - Update device links after probing its driver.
1296 * @dev: Device to update the links for.
1297 *
1298 * The probe has been successful, so update links from this device to any
1299 * consumers by changing their status to "available".
1300 *
1301 * Also change the status of @dev's links to suppliers to "active".
1302 *
1303 * Links without the DL_FLAG_MANAGED flag set are ignored.
1304 */
1305void device_links_driver_bound(struct device *dev)
1306{
1307 struct device_link *link, *ln;
1308 LIST_HEAD(sync_list);
1309
1310 /*
1311 * If a device binds successfully, it's expected to have created all
1312 * the device links it needs to or make new device links as it needs
1313 * them. So, fw_devlink no longer needs to create device links to any
1314 * of the device's suppliers.
1315 *
1316 * Also, if a child firmware node of this bound device is not added as a
1317 * device by now, assume it is never going to be added. Make this bound
1318 * device the fallback supplier to the dangling consumers of the child
1319 * firmware node because this bound device is probably implementing the
1320 * child firmware node functionality and we don't want the dangling
1321 * consumers to defer probe indefinitely waiting for a device for the
1322 * child firmware node.
1323 */
1324 if (dev->fwnode && dev->fwnode->dev == dev) {
1325 struct fwnode_handle *child;
1326 fwnode_links_purge_suppliers(dev->fwnode);
1327 mutex_lock(&fwnode_link_lock);
1328 fwnode_for_each_available_child_node(dev->fwnode, child)
1329 __fw_devlink_pickup_dangling_consumers(child,
1330 dev->fwnode);
1331 __fw_devlink_link_to_consumers(dev);
1332 mutex_unlock(&fwnode_link_lock);
1333 }
1334 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1335
1336 device_links_write_lock();
1337
1338 list_for_each_entry(link, &dev->links.consumers, s_node) {
1339 if (!(link->flags & DL_FLAG_MANAGED))
1340 continue;
1341
1342 /*
1343 * Links created during consumer probe may be in the "consumer
1344 * probe" state to start with if the supplier is still probing
1345 * when they are created and they may become "active" if the
1346 * consumer probe returns first. Skip them here.
1347 */
1348 if (link->status == DL_STATE_CONSUMER_PROBE ||
1349 link->status == DL_STATE_ACTIVE)
1350 continue;
1351
1352 WARN_ON(link->status != DL_STATE_DORMANT);
1353 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1354
1355 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1356 driver_deferred_probe_add(link->consumer);
1357 }
1358
1359 if (defer_sync_state_count)
1360 __device_links_supplier_defer_sync(dev);
1361 else
1362 __device_links_queue_sync_state(dev, &sync_list);
1363
1364 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1365 struct device *supplier;
1366
1367 if (!(link->flags & DL_FLAG_MANAGED))
1368 continue;
1369
1370 supplier = link->supplier;
1371 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1372 /*
1373 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1374 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1375 * save to drop the managed link completely.
1376 */
1377 device_link_drop_managed(link);
1378 } else if (dev_is_best_effort(dev) &&
1379 link->flags & DL_FLAG_INFERRED &&
1380 link->status != DL_STATE_CONSUMER_PROBE &&
1381 !link->supplier->can_match) {
1382 /*
1383 * When dev_is_best_effort() is true, we ignore device
1384 * links to suppliers that don't have a driver. If the
1385 * consumer device still managed to probe, there's no
1386 * point in maintaining a device link in a weird state
1387 * (consumer probed before supplier). So delete it.
1388 */
1389 device_link_drop_managed(link);
1390 } else {
1391 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1392 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1393 }
1394
1395 /*
1396 * This needs to be done even for the deleted
1397 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1398 * device link that was preventing the supplier from getting a
1399 * sync_state() call.
1400 */
1401 if (defer_sync_state_count)
1402 __device_links_supplier_defer_sync(supplier);
1403 else
1404 __device_links_queue_sync_state(supplier, &sync_list);
1405 }
1406
1407 dev->links.status = DL_DEV_DRIVER_BOUND;
1408
1409 device_links_write_unlock();
1410
1411 device_links_flush_sync_list(&sync_list, dev);
1412}
1413
1414/**
1415 * __device_links_no_driver - Update links of a device without a driver.
1416 * @dev: Device without a drvier.
1417 *
1418 * Delete all non-persistent links from this device to any suppliers.
1419 *
1420 * Persistent links stay around, but their status is changed to "available",
1421 * unless they already are in the "supplier unbind in progress" state in which
1422 * case they need not be updated.
1423 *
1424 * Links without the DL_FLAG_MANAGED flag set are ignored.
1425 */
1426static void __device_links_no_driver(struct device *dev)
1427{
1428 struct device_link *link, *ln;
1429
1430 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1431 if (!(link->flags & DL_FLAG_MANAGED))
1432 continue;
1433
1434 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1435 device_link_drop_managed(link);
1436 continue;
1437 }
1438
1439 if (link->status != DL_STATE_CONSUMER_PROBE &&
1440 link->status != DL_STATE_ACTIVE)
1441 continue;
1442
1443 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1444 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1445 } else {
1446 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1447 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1448 }
1449 }
1450
1451 dev->links.status = DL_DEV_NO_DRIVER;
1452}
1453
1454/**
1455 * device_links_no_driver - Update links after failing driver probe.
1456 * @dev: Device whose driver has just failed to probe.
1457 *
1458 * Clean up leftover links to consumers for @dev and invoke
1459 * %__device_links_no_driver() to update links to suppliers for it as
1460 * appropriate.
1461 *
1462 * Links without the DL_FLAG_MANAGED flag set are ignored.
1463 */
1464void device_links_no_driver(struct device *dev)
1465{
1466 struct device_link *link;
1467
1468 device_links_write_lock();
1469
1470 list_for_each_entry(link, &dev->links.consumers, s_node) {
1471 if (!(link->flags & DL_FLAG_MANAGED))
1472 continue;
1473
1474 /*
1475 * The probe has failed, so if the status of the link is
1476 * "consumer probe" or "active", it must have been added by
1477 * a probing consumer while this device was still probing.
1478 * Change its state to "dormant", as it represents a valid
1479 * relationship, but it is not functionally meaningful.
1480 */
1481 if (link->status == DL_STATE_CONSUMER_PROBE ||
1482 link->status == DL_STATE_ACTIVE)
1483 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1484 }
1485
1486 __device_links_no_driver(dev);
1487
1488 device_links_write_unlock();
1489}
1490
1491/**
1492 * device_links_driver_cleanup - Update links after driver removal.
1493 * @dev: Device whose driver has just gone away.
1494 *
1495 * Update links to consumers for @dev by changing their status to "dormant" and
1496 * invoke %__device_links_no_driver() to update links to suppliers for it as
1497 * appropriate.
1498 *
1499 * Links without the DL_FLAG_MANAGED flag set are ignored.
1500 */
1501void device_links_driver_cleanup(struct device *dev)
1502{
1503 struct device_link *link, *ln;
1504
1505 device_links_write_lock();
1506
1507 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1508 if (!(link->flags & DL_FLAG_MANAGED))
1509 continue;
1510
1511 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1512 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1513
1514 /*
1515 * autoremove the links between this @dev and its consumer
1516 * devices that are not active, i.e. where the link state
1517 * has moved to DL_STATE_SUPPLIER_UNBIND.
1518 */
1519 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1520 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1521 device_link_drop_managed(link);
1522
1523 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1524 }
1525
1526 list_del_init(&dev->links.defer_sync);
1527 __device_links_no_driver(dev);
1528
1529 device_links_write_unlock();
1530}
1531
1532/**
1533 * device_links_busy - Check if there are any busy links to consumers.
1534 * @dev: Device to check.
1535 *
1536 * Check each consumer of the device and return 'true' if its link's status
1537 * is one of "consumer probe" or "active" (meaning that the given consumer is
1538 * probing right now or its driver is present). Otherwise, change the link
1539 * state to "supplier unbind" to prevent the consumer from being probed
1540 * successfully going forward.
1541 *
1542 * Return 'false' if there are no probing or active consumers.
1543 *
1544 * Links without the DL_FLAG_MANAGED flag set are ignored.
1545 */
1546bool device_links_busy(struct device *dev)
1547{
1548 struct device_link *link;
1549 bool ret = false;
1550
1551 device_links_write_lock();
1552
1553 list_for_each_entry(link, &dev->links.consumers, s_node) {
1554 if (!(link->flags & DL_FLAG_MANAGED))
1555 continue;
1556
1557 if (link->status == DL_STATE_CONSUMER_PROBE
1558 || link->status == DL_STATE_ACTIVE) {
1559 ret = true;
1560 break;
1561 }
1562 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1563 }
1564
1565 dev->links.status = DL_DEV_UNBINDING;
1566
1567 device_links_write_unlock();
1568 return ret;
1569}
1570
1571/**
1572 * device_links_unbind_consumers - Force unbind consumers of the given device.
1573 * @dev: Device to unbind the consumers of.
1574 *
1575 * Walk the list of links to consumers for @dev and if any of them is in the
1576 * "consumer probe" state, wait for all device probes in progress to complete
1577 * and start over.
1578 *
1579 * If that's not the case, change the status of the link to "supplier unbind"
1580 * and check if the link was in the "active" state. If so, force the consumer
1581 * driver to unbind and start over (the consumer will not re-probe as we have
1582 * changed the state of the link already).
1583 *
1584 * Links without the DL_FLAG_MANAGED flag set are ignored.
1585 */
1586void device_links_unbind_consumers(struct device *dev)
1587{
1588 struct device_link *link;
1589
1590 start:
1591 device_links_write_lock();
1592
1593 list_for_each_entry(link, &dev->links.consumers, s_node) {
1594 enum device_link_state status;
1595
1596 if (!(link->flags & DL_FLAG_MANAGED) ||
1597 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1598 continue;
1599
1600 status = link->status;
1601 if (status == DL_STATE_CONSUMER_PROBE) {
1602 device_links_write_unlock();
1603
1604 wait_for_device_probe();
1605 goto start;
1606 }
1607 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1608 if (status == DL_STATE_ACTIVE) {
1609 struct device *consumer = link->consumer;
1610
1611 get_device(consumer);
1612
1613 device_links_write_unlock();
1614
1615 device_release_driver_internal(consumer, NULL,
1616 consumer->parent);
1617 put_device(consumer);
1618 goto start;
1619 }
1620 }
1621
1622 device_links_write_unlock();
1623}
1624
1625/**
1626 * device_links_purge - Delete existing links to other devices.
1627 * @dev: Target device.
1628 */
1629static void device_links_purge(struct device *dev)
1630{
1631 struct device_link *link, *ln;
1632
1633 if (dev->class == &devlink_class)
1634 return;
1635
1636 /*
1637 * Delete all of the remaining links from this device to any other
1638 * devices (either consumers or suppliers).
1639 */
1640 device_links_write_lock();
1641
1642 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1643 WARN_ON(link->status == DL_STATE_ACTIVE);
1644 __device_link_del(&link->kref);
1645 }
1646
1647 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1648 WARN_ON(link->status != DL_STATE_DORMANT &&
1649 link->status != DL_STATE_NONE);
1650 __device_link_del(&link->kref);
1651 }
1652
1653 device_links_write_unlock();
1654}
1655
1656#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1657 DL_FLAG_SYNC_STATE_ONLY)
1658#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1659 DL_FLAG_AUTOPROBE_CONSUMER)
1660#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1661 DL_FLAG_PM_RUNTIME)
1662
1663static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1664static int __init fw_devlink_setup(char *arg)
1665{
1666 if (!arg)
1667 return -EINVAL;
1668
1669 if (strcmp(arg, "off") == 0) {
1670 fw_devlink_flags = 0;
1671 } else if (strcmp(arg, "permissive") == 0) {
1672 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1673 } else if (strcmp(arg, "on") == 0) {
1674 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1675 } else if (strcmp(arg, "rpm") == 0) {
1676 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1677 }
1678 return 0;
1679}
1680early_param("fw_devlink", fw_devlink_setup);
1681
1682static bool fw_devlink_strict;
1683static int __init fw_devlink_strict_setup(char *arg)
1684{
1685 return kstrtobool(arg, &fw_devlink_strict);
1686}
1687early_param("fw_devlink.strict", fw_devlink_strict_setup);
1688
1689#define FW_DEVLINK_SYNC_STATE_STRICT 0
1690#define FW_DEVLINK_SYNC_STATE_TIMEOUT 1
1691
1692#ifndef CONFIG_FW_DEVLINK_SYNC_STATE_TIMEOUT
1693static int fw_devlink_sync_state;
1694#else
1695static int fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1696#endif
1697
1698static int __init fw_devlink_sync_state_setup(char *arg)
1699{
1700 if (!arg)
1701 return -EINVAL;
1702
1703 if (strcmp(arg, "strict") == 0) {
1704 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_STRICT;
1705 return 0;
1706 } else if (strcmp(arg, "timeout") == 0) {
1707 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1708 return 0;
1709 }
1710 return -EINVAL;
1711}
1712early_param("fw_devlink.sync_state", fw_devlink_sync_state_setup);
1713
1714static inline u32 fw_devlink_get_flags(u8 fwlink_flags)
1715{
1716 if (fwlink_flags & FWLINK_FLAG_CYCLE)
1717 return FW_DEVLINK_FLAGS_PERMISSIVE | DL_FLAG_CYCLE;
1718
1719 return fw_devlink_flags;
1720}
1721
1722static bool fw_devlink_is_permissive(void)
1723{
1724 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1725}
1726
1727bool fw_devlink_is_strict(void)
1728{
1729 return fw_devlink_strict && !fw_devlink_is_permissive();
1730}
1731
1732static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1733{
1734 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1735 return;
1736
1737 fwnode_call_int_op(fwnode, add_links);
1738 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1739}
1740
1741static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1742{
1743 struct fwnode_handle *child = NULL;
1744
1745 fw_devlink_parse_fwnode(fwnode);
1746
1747 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1748 fw_devlink_parse_fwtree(child);
1749}
1750
1751static void fw_devlink_relax_link(struct device_link *link)
1752{
1753 if (!(link->flags & DL_FLAG_INFERRED))
1754 return;
1755
1756 if (device_link_flag_is_sync_state_only(link->flags))
1757 return;
1758
1759 pm_runtime_drop_link(link);
1760 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1761 dev_dbg(link->consumer, "Relaxing link with %s\n",
1762 dev_name(link->supplier));
1763}
1764
1765static int fw_devlink_no_driver(struct device *dev, void *data)
1766{
1767 struct device_link *link = to_devlink(dev);
1768
1769 if (!link->supplier->can_match)
1770 fw_devlink_relax_link(link);
1771
1772 return 0;
1773}
1774
1775void fw_devlink_drivers_done(void)
1776{
1777 fw_devlink_drv_reg_done = true;
1778 device_links_write_lock();
1779 class_for_each_device(&devlink_class, NULL, NULL,
1780 fw_devlink_no_driver);
1781 device_links_write_unlock();
1782}
1783
1784static int fw_devlink_dev_sync_state(struct device *dev, void *data)
1785{
1786 struct device_link *link = to_devlink(dev);
1787 struct device *sup = link->supplier;
1788
1789 if (!(link->flags & DL_FLAG_MANAGED) ||
1790 link->status == DL_STATE_ACTIVE || sup->state_synced ||
1791 !dev_has_sync_state(sup))
1792 return 0;
1793
1794 if (fw_devlink_sync_state == FW_DEVLINK_SYNC_STATE_STRICT) {
1795 dev_warn(sup, "sync_state() pending due to %s\n",
1796 dev_name(link->consumer));
1797 return 0;
1798 }
1799
1800 if (!list_empty(&sup->links.defer_sync))
1801 return 0;
1802
1803 dev_warn(sup, "Timed out. Forcing sync_state()\n");
1804 sup->state_synced = true;
1805 get_device(sup);
1806 list_add_tail(&sup->links.defer_sync, data);
1807
1808 return 0;
1809}
1810
1811void fw_devlink_probing_done(void)
1812{
1813 LIST_HEAD(sync_list);
1814
1815 device_links_write_lock();
1816 class_for_each_device(&devlink_class, NULL, &sync_list,
1817 fw_devlink_dev_sync_state);
1818 device_links_write_unlock();
1819 device_links_flush_sync_list(&sync_list, NULL);
1820}
1821
1822/**
1823 * wait_for_init_devices_probe - Try to probe any device needed for init
1824 *
1825 * Some devices might need to be probed and bound successfully before the kernel
1826 * boot sequence can finish and move on to init/userspace. For example, a
1827 * network interface might need to be bound to be able to mount a NFS rootfs.
1828 *
1829 * With fw_devlink=on by default, some of these devices might be blocked from
1830 * probing because they are waiting on a optional supplier that doesn't have a
1831 * driver. While fw_devlink will eventually identify such devices and unblock
1832 * the probing automatically, it might be too late by the time it unblocks the
1833 * probing of devices. For example, the IP4 autoconfig might timeout before
1834 * fw_devlink unblocks probing of the network interface.
1835 *
1836 * This function is available to temporarily try and probe all devices that have
1837 * a driver even if some of their suppliers haven't been added or don't have
1838 * drivers.
1839 *
1840 * The drivers can then decide which of the suppliers are optional vs mandatory
1841 * and probe the device if possible. By the time this function returns, all such
1842 * "best effort" probes are guaranteed to be completed. If a device successfully
1843 * probes in this mode, we delete all fw_devlink discovered dependencies of that
1844 * device where the supplier hasn't yet probed successfully because they have to
1845 * be optional dependencies.
1846 *
1847 * Any devices that didn't successfully probe go back to being treated as if
1848 * this function was never called.
1849 *
1850 * This also means that some devices that aren't needed for init and could have
1851 * waited for their optional supplier to probe (when the supplier's module is
1852 * loaded later on) would end up probing prematurely with limited functionality.
1853 * So call this function only when boot would fail without it.
1854 */
1855void __init wait_for_init_devices_probe(void)
1856{
1857 if (!fw_devlink_flags || fw_devlink_is_permissive())
1858 return;
1859
1860 /*
1861 * Wait for all ongoing probes to finish so that the "best effort" is
1862 * only applied to devices that can't probe otherwise.
1863 */
1864 wait_for_device_probe();
1865
1866 pr_info("Trying to probe devices needed for running init ...\n");
1867 fw_devlink_best_effort = true;
1868 driver_deferred_probe_trigger();
1869
1870 /*
1871 * Wait for all "best effort" probes to finish before going back to
1872 * normal enforcement.
1873 */
1874 wait_for_device_probe();
1875 fw_devlink_best_effort = false;
1876}
1877
1878static void fw_devlink_unblock_consumers(struct device *dev)
1879{
1880 struct device_link *link;
1881
1882 if (!fw_devlink_flags || fw_devlink_is_permissive())
1883 return;
1884
1885 device_links_write_lock();
1886 list_for_each_entry(link, &dev->links.consumers, s_node)
1887 fw_devlink_relax_link(link);
1888 device_links_write_unlock();
1889}
1890
1891#define get_dev_from_fwnode(fwnode) get_device((fwnode)->dev)
1892
1893static bool fwnode_init_without_drv(struct fwnode_handle *fwnode)
1894{
1895 struct device *dev;
1896 bool ret;
1897
1898 if (!(fwnode->flags & FWNODE_FLAG_INITIALIZED))
1899 return false;
1900
1901 dev = get_dev_from_fwnode(fwnode);
1902 ret = !dev || dev->links.status == DL_DEV_NO_DRIVER;
1903 put_device(dev);
1904
1905 return ret;
1906}
1907
1908static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
1909{
1910 struct fwnode_handle *parent;
1911
1912 fwnode_for_each_parent_node(fwnode, parent) {
1913 if (fwnode_init_without_drv(parent)) {
1914 fwnode_handle_put(parent);
1915 return true;
1916 }
1917 }
1918
1919 return false;
1920}
1921
1922/**
1923 * fwnode_is_ancestor_of - Test if @ancestor is ancestor of @child
1924 * @ancestor: Firmware which is tested for being an ancestor
1925 * @child: Firmware which is tested for being the child
1926 *
1927 * A node is considered an ancestor of itself too.
1928 *
1929 * Return: true if @ancestor is an ancestor of @child. Otherwise, returns false.
1930 */
1931static bool fwnode_is_ancestor_of(const struct fwnode_handle *ancestor,
1932 const struct fwnode_handle *child)
1933{
1934 struct fwnode_handle *parent;
1935
1936 if (IS_ERR_OR_NULL(ancestor))
1937 return false;
1938
1939 if (child == ancestor)
1940 return true;
1941
1942 fwnode_for_each_parent_node(child, parent) {
1943 if (parent == ancestor) {
1944 fwnode_handle_put(parent);
1945 return true;
1946 }
1947 }
1948 return false;
1949}
1950
1951/**
1952 * fwnode_get_next_parent_dev - Find device of closest ancestor fwnode
1953 * @fwnode: firmware node
1954 *
1955 * Given a firmware node (@fwnode), this function finds its closest ancestor
1956 * firmware node that has a corresponding struct device and returns that struct
1957 * device.
1958 *
1959 * The caller is responsible for calling put_device() on the returned device
1960 * pointer.
1961 *
1962 * Return: a pointer to the device of the @fwnode's closest ancestor.
1963 */
1964static struct device *fwnode_get_next_parent_dev(const struct fwnode_handle *fwnode)
1965{
1966 struct fwnode_handle *parent;
1967 struct device *dev;
1968
1969 fwnode_for_each_parent_node(fwnode, parent) {
1970 dev = get_dev_from_fwnode(parent);
1971 if (dev) {
1972 fwnode_handle_put(parent);
1973 return dev;
1974 }
1975 }
1976 return NULL;
1977}
1978
1979/**
1980 * __fw_devlink_relax_cycles - Relax and mark dependency cycles.
1981 * @con: Potential consumer device.
1982 * @sup_handle: Potential supplier's fwnode.
1983 *
1984 * Needs to be called with fwnode_lock and device link lock held.
1985 *
1986 * Check if @sup_handle or any of its ancestors or suppliers direct/indirectly
1987 * depend on @con. This function can detect multiple cyles between @sup_handle
1988 * and @con. When such dependency cycles are found, convert all device links
1989 * created solely by fw_devlink into SYNC_STATE_ONLY device links. Also, mark
1990 * all fwnode links in the cycle with FWLINK_FLAG_CYCLE so that when they are
1991 * converted into a device link in the future, they are created as
1992 * SYNC_STATE_ONLY device links. This is the equivalent of doing
1993 * fw_devlink=permissive just between the devices in the cycle. We need to do
1994 * this because, at this point, fw_devlink can't tell which of these
1995 * dependencies is not a real dependency.
1996 *
1997 * Return true if one or more cycles were found. Otherwise, return false.
1998 */
1999static bool __fw_devlink_relax_cycles(struct device *con,
2000 struct fwnode_handle *sup_handle)
2001{
2002 struct device *sup_dev = NULL, *par_dev = NULL;
2003 struct fwnode_link *link;
2004 struct device_link *dev_link;
2005 bool ret = false;
2006
2007 if (!sup_handle)
2008 return false;
2009
2010 /*
2011 * We aren't trying to find all cycles. Just a cycle between con and
2012 * sup_handle.
2013 */
2014 if (sup_handle->flags & FWNODE_FLAG_VISITED)
2015 return false;
2016
2017 sup_handle->flags |= FWNODE_FLAG_VISITED;
2018
2019 sup_dev = get_dev_from_fwnode(sup_handle);
2020
2021 /* Termination condition. */
2022 if (sup_dev == con) {
2023 pr_debug("----- cycle: start -----\n");
2024 ret = true;
2025 goto out;
2026 }
2027
2028 /*
2029 * If sup_dev is bound to a driver and @con hasn't started binding to a
2030 * driver, sup_dev can't be a consumer of @con. So, no need to check
2031 * further.
2032 */
2033 if (sup_dev && sup_dev->links.status == DL_DEV_DRIVER_BOUND &&
2034 con->links.status == DL_DEV_NO_DRIVER) {
2035 ret = false;
2036 goto out;
2037 }
2038
2039 list_for_each_entry(link, &sup_handle->suppliers, c_hook) {
2040 if (link->flags & FWLINK_FLAG_IGNORE)
2041 continue;
2042
2043 if (__fw_devlink_relax_cycles(con, link->supplier)) {
2044 __fwnode_link_cycle(link);
2045 ret = true;
2046 }
2047 }
2048
2049 /*
2050 * Give priority to device parent over fwnode parent to account for any
2051 * quirks in how fwnodes are converted to devices.
2052 */
2053 if (sup_dev)
2054 par_dev = get_device(sup_dev->parent);
2055 else
2056 par_dev = fwnode_get_next_parent_dev(sup_handle);
2057
2058 if (par_dev && __fw_devlink_relax_cycles(con, par_dev->fwnode)) {
2059 pr_debug("%pfwf: cycle: child of %pfwf\n", sup_handle,
2060 par_dev->fwnode);
2061 ret = true;
2062 }
2063
2064 if (!sup_dev)
2065 goto out;
2066
2067 list_for_each_entry(dev_link, &sup_dev->links.suppliers, c_node) {
2068 /*
2069 * Ignore a SYNC_STATE_ONLY flag only if it wasn't marked as
2070 * such due to a cycle.
2071 */
2072 if (device_link_flag_is_sync_state_only(dev_link->flags) &&
2073 !(dev_link->flags & DL_FLAG_CYCLE))
2074 continue;
2075
2076 if (__fw_devlink_relax_cycles(con,
2077 dev_link->supplier->fwnode)) {
2078 pr_debug("%pfwf: cycle: depends on %pfwf\n", sup_handle,
2079 dev_link->supplier->fwnode);
2080 fw_devlink_relax_link(dev_link);
2081 dev_link->flags |= DL_FLAG_CYCLE;
2082 ret = true;
2083 }
2084 }
2085
2086out:
2087 sup_handle->flags &= ~FWNODE_FLAG_VISITED;
2088 put_device(sup_dev);
2089 put_device(par_dev);
2090 return ret;
2091}
2092
2093/**
2094 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
2095 * @con: consumer device for the device link
2096 * @sup_handle: fwnode handle of supplier
2097 * @link: fwnode link that's being converted to a device link
2098 *
2099 * This function will try to create a device link between the consumer device
2100 * @con and the supplier device represented by @sup_handle.
2101 *
2102 * The supplier has to be provided as a fwnode because incorrect cycles in
2103 * fwnode links can sometimes cause the supplier device to never be created.
2104 * This function detects such cases and returns an error if it cannot create a
2105 * device link from the consumer to a missing supplier.
2106 *
2107 * Returns,
2108 * 0 on successfully creating a device link
2109 * -EINVAL if the device link cannot be created as expected
2110 * -EAGAIN if the device link cannot be created right now, but it may be
2111 * possible to do that in the future
2112 */
2113static int fw_devlink_create_devlink(struct device *con,
2114 struct fwnode_handle *sup_handle,
2115 struct fwnode_link *link)
2116{
2117 struct device *sup_dev;
2118 int ret = 0;
2119 u32 flags;
2120
2121 if (link->flags & FWLINK_FLAG_IGNORE)
2122 return 0;
2123
2124 if (con->fwnode == link->consumer)
2125 flags = fw_devlink_get_flags(link->flags);
2126 else
2127 flags = FW_DEVLINK_FLAGS_PERMISSIVE;
2128
2129 /*
2130 * In some cases, a device P might also be a supplier to its child node
2131 * C. However, this would defer the probe of C until the probe of P
2132 * completes successfully. This is perfectly fine in the device driver
2133 * model. device_add() doesn't guarantee probe completion of the device
2134 * by the time it returns.
2135 *
2136 * However, there are a few drivers that assume C will finish probing
2137 * as soon as it's added and before P finishes probing. So, we provide
2138 * a flag to let fw_devlink know not to delay the probe of C until the
2139 * probe of P completes successfully.
2140 *
2141 * When such a flag is set, we can't create device links where P is the
2142 * supplier of C as that would delay the probe of C.
2143 */
2144 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
2145 fwnode_is_ancestor_of(sup_handle, con->fwnode))
2146 return -EINVAL;
2147
2148 /*
2149 * SYNC_STATE_ONLY device links don't block probing and supports cycles.
2150 * So, one might expect that cycle detection isn't necessary for them.
2151 * However, if the device link was marked as SYNC_STATE_ONLY because
2152 * it's part of a cycle, then we still need to do cycle detection. This
2153 * is because the consumer and supplier might be part of multiple cycles
2154 * and we need to detect all those cycles.
2155 */
2156 if (!device_link_flag_is_sync_state_only(flags) ||
2157 flags & DL_FLAG_CYCLE) {
2158 device_links_write_lock();
2159 if (__fw_devlink_relax_cycles(con, sup_handle)) {
2160 __fwnode_link_cycle(link);
2161 flags = fw_devlink_get_flags(link->flags);
2162 pr_debug("----- cycle: end -----\n");
2163 dev_info(con, "Fixed dependency cycle(s) with %pfwf\n",
2164 sup_handle);
2165 }
2166 device_links_write_unlock();
2167 }
2168
2169 if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE)
2170 sup_dev = fwnode_get_next_parent_dev(sup_handle);
2171 else
2172 sup_dev = get_dev_from_fwnode(sup_handle);
2173
2174 if (sup_dev) {
2175 /*
2176 * If it's one of those drivers that don't actually bind to
2177 * their device using driver core, then don't wait on this
2178 * supplier device indefinitely.
2179 */
2180 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
2181 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
2182 dev_dbg(con,
2183 "Not linking %pfwf - dev might never probe\n",
2184 sup_handle);
2185 ret = -EINVAL;
2186 goto out;
2187 }
2188
2189 if (con != sup_dev && !device_link_add(con, sup_dev, flags)) {
2190 dev_err(con, "Failed to create device link (0x%x) with %s\n",
2191 flags, dev_name(sup_dev));
2192 ret = -EINVAL;
2193 }
2194
2195 goto out;
2196 }
2197
2198 /*
2199 * Supplier or supplier's ancestor already initialized without a struct
2200 * device or being probed by a driver.
2201 */
2202 if (fwnode_init_without_drv(sup_handle) ||
2203 fwnode_ancestor_init_without_drv(sup_handle)) {
2204 dev_dbg(con, "Not linking %pfwf - might never become dev\n",
2205 sup_handle);
2206 return -EINVAL;
2207 }
2208
2209 ret = -EAGAIN;
2210out:
2211 put_device(sup_dev);
2212 return ret;
2213}
2214
2215/**
2216 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
2217 * @dev: Device that needs to be linked to its consumers
2218 *
2219 * This function looks at all the consumer fwnodes of @dev and creates device
2220 * links between the consumer device and @dev (supplier).
2221 *
2222 * If the consumer device has not been added yet, then this function creates a
2223 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
2224 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
2225 * sync_state() callback before the real consumer device gets to be added and
2226 * then probed.
2227 *
2228 * Once device links are created from the real consumer to @dev (supplier), the
2229 * fwnode links are deleted.
2230 */
2231static void __fw_devlink_link_to_consumers(struct device *dev)
2232{
2233 struct fwnode_handle *fwnode = dev->fwnode;
2234 struct fwnode_link *link, *tmp;
2235
2236 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
2237 struct device *con_dev;
2238 bool own_link = true;
2239 int ret;
2240
2241 con_dev = get_dev_from_fwnode(link->consumer);
2242 /*
2243 * If consumer device is not available yet, make a "proxy"
2244 * SYNC_STATE_ONLY link from the consumer's parent device to
2245 * the supplier device. This is necessary to make sure the
2246 * supplier doesn't get a sync_state() callback before the real
2247 * consumer can create a device link to the supplier.
2248 *
2249 * This proxy link step is needed to handle the case where the
2250 * consumer's parent device is added before the supplier.
2251 */
2252 if (!con_dev) {
2253 con_dev = fwnode_get_next_parent_dev(link->consumer);
2254 /*
2255 * However, if the consumer's parent device is also the
2256 * parent of the supplier, don't create a
2257 * consumer-supplier link from the parent to its child
2258 * device. Such a dependency is impossible.
2259 */
2260 if (con_dev &&
2261 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
2262 put_device(con_dev);
2263 con_dev = NULL;
2264 } else {
2265 own_link = false;
2266 }
2267 }
2268
2269 if (!con_dev)
2270 continue;
2271
2272 ret = fw_devlink_create_devlink(con_dev, fwnode, link);
2273 put_device(con_dev);
2274 if (!own_link || ret == -EAGAIN)
2275 continue;
2276
2277 __fwnode_link_del(link);
2278 }
2279}
2280
2281/**
2282 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
2283 * @dev: The consumer device that needs to be linked to its suppliers
2284 * @fwnode: Root of the fwnode tree that is used to create device links
2285 *
2286 * This function looks at all the supplier fwnodes of fwnode tree rooted at
2287 * @fwnode and creates device links between @dev (consumer) and all the
2288 * supplier devices of the entire fwnode tree at @fwnode.
2289 *
2290 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
2291 * and the real suppliers of @dev. Once these device links are created, the
2292 * fwnode links are deleted.
2293 *
2294 * In addition, it also looks at all the suppliers of the entire fwnode tree
2295 * because some of the child devices of @dev that have not been added yet
2296 * (because @dev hasn't probed) might already have their suppliers added to
2297 * driver core. So, this function creates SYNC_STATE_ONLY device links between
2298 * @dev (consumer) and these suppliers to make sure they don't execute their
2299 * sync_state() callbacks before these child devices have a chance to create
2300 * their device links. The fwnode links that correspond to the child devices
2301 * aren't delete because they are needed later to create the device links
2302 * between the real consumer and supplier devices.
2303 */
2304static void __fw_devlink_link_to_suppliers(struct device *dev,
2305 struct fwnode_handle *fwnode)
2306{
2307 bool own_link = (dev->fwnode == fwnode);
2308 struct fwnode_link *link, *tmp;
2309 struct fwnode_handle *child = NULL;
2310
2311 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
2312 int ret;
2313 struct fwnode_handle *sup = link->supplier;
2314
2315 ret = fw_devlink_create_devlink(dev, sup, link);
2316 if (!own_link || ret == -EAGAIN)
2317 continue;
2318
2319 __fwnode_link_del(link);
2320 }
2321
2322 /*
2323 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
2324 * all the descendants. This proxy link step is needed to handle the
2325 * case where the supplier is added before the consumer's parent device
2326 * (@dev).
2327 */
2328 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
2329 __fw_devlink_link_to_suppliers(dev, child);
2330}
2331
2332static void fw_devlink_link_device(struct device *dev)
2333{
2334 struct fwnode_handle *fwnode = dev->fwnode;
2335
2336 if (!fw_devlink_flags)
2337 return;
2338
2339 fw_devlink_parse_fwtree(fwnode);
2340
2341 mutex_lock(&fwnode_link_lock);
2342 __fw_devlink_link_to_consumers(dev);
2343 __fw_devlink_link_to_suppliers(dev, fwnode);
2344 mutex_unlock(&fwnode_link_lock);
2345}
2346
2347/* Device links support end. */
2348
2349int (*platform_notify)(struct device *dev) = NULL;
2350int (*platform_notify_remove)(struct device *dev) = NULL;
2351static struct kobject *dev_kobj;
2352
2353/* /sys/dev/char */
2354static struct kobject *sysfs_dev_char_kobj;
2355
2356/* /sys/dev/block */
2357static struct kobject *sysfs_dev_block_kobj;
2358
2359static DEFINE_MUTEX(device_hotplug_lock);
2360
2361void lock_device_hotplug(void)
2362{
2363 mutex_lock(&device_hotplug_lock);
2364}
2365
2366void unlock_device_hotplug(void)
2367{
2368 mutex_unlock(&device_hotplug_lock);
2369}
2370
2371int lock_device_hotplug_sysfs(void)
2372{
2373 if (mutex_trylock(&device_hotplug_lock))
2374 return 0;
2375
2376 /* Avoid busy looping (5 ms of sleep should do). */
2377 msleep(5);
2378 return restart_syscall();
2379}
2380
2381#ifdef CONFIG_BLOCK
2382static inline int device_is_not_partition(struct device *dev)
2383{
2384 return !(dev->type == &part_type);
2385}
2386#else
2387static inline int device_is_not_partition(struct device *dev)
2388{
2389 return 1;
2390}
2391#endif
2392
2393static void device_platform_notify(struct device *dev)
2394{
2395 acpi_device_notify(dev);
2396
2397 software_node_notify(dev);
2398
2399 if (platform_notify)
2400 platform_notify(dev);
2401}
2402
2403static void device_platform_notify_remove(struct device *dev)
2404{
2405 if (platform_notify_remove)
2406 platform_notify_remove(dev);
2407
2408 software_node_notify_remove(dev);
2409
2410 acpi_device_notify_remove(dev);
2411}
2412
2413/**
2414 * dev_driver_string - Return a device's driver name, if at all possible
2415 * @dev: struct device to get the name of
2416 *
2417 * Will return the device's driver's name if it is bound to a device. If
2418 * the device is not bound to a driver, it will return the name of the bus
2419 * it is attached to. If it is not attached to a bus either, an empty
2420 * string will be returned.
2421 */
2422const char *dev_driver_string(const struct device *dev)
2423{
2424 struct device_driver *drv;
2425
2426 /* dev->driver can change to NULL underneath us because of unbinding,
2427 * so be careful about accessing it. dev->bus and dev->class should
2428 * never change once they are set, so they don't need special care.
2429 */
2430 drv = READ_ONCE(dev->driver);
2431 return drv ? drv->name : dev_bus_name(dev);
2432}
2433EXPORT_SYMBOL(dev_driver_string);
2434
2435#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2436
2437static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2438 char *buf)
2439{
2440 struct device_attribute *dev_attr = to_dev_attr(attr);
2441 struct device *dev = kobj_to_dev(kobj);
2442 ssize_t ret = -EIO;
2443
2444 if (dev_attr->show)
2445 ret = dev_attr->show(dev, dev_attr, buf);
2446 if (ret >= (ssize_t)PAGE_SIZE) {
2447 printk("dev_attr_show: %pS returned bad count\n",
2448 dev_attr->show);
2449 }
2450 return ret;
2451}
2452
2453static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2454 const char *buf, size_t count)
2455{
2456 struct device_attribute *dev_attr = to_dev_attr(attr);
2457 struct device *dev = kobj_to_dev(kobj);
2458 ssize_t ret = -EIO;
2459
2460 if (dev_attr->store)
2461 ret = dev_attr->store(dev, dev_attr, buf, count);
2462 return ret;
2463}
2464
2465static const struct sysfs_ops dev_sysfs_ops = {
2466 .show = dev_attr_show,
2467 .store = dev_attr_store,
2468};
2469
2470#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2471
2472ssize_t device_store_ulong(struct device *dev,
2473 struct device_attribute *attr,
2474 const char *buf, size_t size)
2475{
2476 struct dev_ext_attribute *ea = to_ext_attr(attr);
2477 int ret;
2478 unsigned long new;
2479
2480 ret = kstrtoul(buf, 0, &new);
2481 if (ret)
2482 return ret;
2483 *(unsigned long *)(ea->var) = new;
2484 /* Always return full write size even if we didn't consume all */
2485 return size;
2486}
2487EXPORT_SYMBOL_GPL(device_store_ulong);
2488
2489ssize_t device_show_ulong(struct device *dev,
2490 struct device_attribute *attr,
2491 char *buf)
2492{
2493 struct dev_ext_attribute *ea = to_ext_attr(attr);
2494 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2495}
2496EXPORT_SYMBOL_GPL(device_show_ulong);
2497
2498ssize_t device_store_int(struct device *dev,
2499 struct device_attribute *attr,
2500 const char *buf, size_t size)
2501{
2502 struct dev_ext_attribute *ea = to_ext_attr(attr);
2503 int ret;
2504 long new;
2505
2506 ret = kstrtol(buf, 0, &new);
2507 if (ret)
2508 return ret;
2509
2510 if (new > INT_MAX || new < INT_MIN)
2511 return -EINVAL;
2512 *(int *)(ea->var) = new;
2513 /* Always return full write size even if we didn't consume all */
2514 return size;
2515}
2516EXPORT_SYMBOL_GPL(device_store_int);
2517
2518ssize_t device_show_int(struct device *dev,
2519 struct device_attribute *attr,
2520 char *buf)
2521{
2522 struct dev_ext_attribute *ea = to_ext_attr(attr);
2523
2524 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2525}
2526EXPORT_SYMBOL_GPL(device_show_int);
2527
2528ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2529 const char *buf, size_t size)
2530{
2531 struct dev_ext_attribute *ea = to_ext_attr(attr);
2532
2533 if (kstrtobool(buf, ea->var) < 0)
2534 return -EINVAL;
2535
2536 return size;
2537}
2538EXPORT_SYMBOL_GPL(device_store_bool);
2539
2540ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2541 char *buf)
2542{
2543 struct dev_ext_attribute *ea = to_ext_attr(attr);
2544
2545 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2546}
2547EXPORT_SYMBOL_GPL(device_show_bool);
2548
2549/**
2550 * device_release - free device structure.
2551 * @kobj: device's kobject.
2552 *
2553 * This is called once the reference count for the object
2554 * reaches 0. We forward the call to the device's release
2555 * method, which should handle actually freeing the structure.
2556 */
2557static void device_release(struct kobject *kobj)
2558{
2559 struct device *dev = kobj_to_dev(kobj);
2560 struct device_private *p = dev->p;
2561
2562 /*
2563 * Some platform devices are driven without driver attached
2564 * and managed resources may have been acquired. Make sure
2565 * all resources are released.
2566 *
2567 * Drivers still can add resources into device after device
2568 * is deleted but alive, so release devres here to avoid
2569 * possible memory leak.
2570 */
2571 devres_release_all(dev);
2572
2573 kfree(dev->dma_range_map);
2574
2575 if (dev->release)
2576 dev->release(dev);
2577 else if (dev->type && dev->type->release)
2578 dev->type->release(dev);
2579 else if (dev->class && dev->class->dev_release)
2580 dev->class->dev_release(dev);
2581 else
2582 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",
2583 dev_name(dev));
2584 kfree(p);
2585}
2586
2587static const void *device_namespace(const struct kobject *kobj)
2588{
2589 const struct device *dev = kobj_to_dev(kobj);
2590 const void *ns = NULL;
2591
2592 if (dev->class && dev->class->ns_type)
2593 ns = dev->class->namespace(dev);
2594
2595 return ns;
2596}
2597
2598static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2599{
2600 const struct device *dev = kobj_to_dev(kobj);
2601
2602 if (dev->class && dev->class->get_ownership)
2603 dev->class->get_ownership(dev, uid, gid);
2604}
2605
2606static const struct kobj_type device_ktype = {
2607 .release = device_release,
2608 .sysfs_ops = &dev_sysfs_ops,
2609 .namespace = device_namespace,
2610 .get_ownership = device_get_ownership,
2611};
2612
2613
2614static int dev_uevent_filter(const struct kobject *kobj)
2615{
2616 const struct kobj_type *ktype = get_ktype(kobj);
2617
2618 if (ktype == &device_ktype) {
2619 const struct device *dev = kobj_to_dev(kobj);
2620 if (dev->bus)
2621 return 1;
2622 if (dev->class)
2623 return 1;
2624 }
2625 return 0;
2626}
2627
2628static const char *dev_uevent_name(const struct kobject *kobj)
2629{
2630 const struct device *dev = kobj_to_dev(kobj);
2631
2632 if (dev->bus)
2633 return dev->bus->name;
2634 if (dev->class)
2635 return dev->class->name;
2636 return NULL;
2637}
2638
2639static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
2640{
2641 const struct device *dev = kobj_to_dev(kobj);
2642 int retval = 0;
2643
2644 /* add device node properties if present */
2645 if (MAJOR(dev->devt)) {
2646 const char *tmp;
2647 const char *name;
2648 umode_t mode = 0;
2649 kuid_t uid = GLOBAL_ROOT_UID;
2650 kgid_t gid = GLOBAL_ROOT_GID;
2651
2652 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2653 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2654 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2655 if (name) {
2656 add_uevent_var(env, "DEVNAME=%s", name);
2657 if (mode)
2658 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2659 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2660 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2661 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2662 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2663 kfree(tmp);
2664 }
2665 }
2666
2667 if (dev->type && dev->type->name)
2668 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2669
2670 if (dev->driver)
2671 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2672
2673 /* Add common DT information about the device */
2674 of_device_uevent(dev, env);
2675
2676 /* have the bus specific function add its stuff */
2677 if (dev->bus && dev->bus->uevent) {
2678 retval = dev->bus->uevent(dev, env);
2679 if (retval)
2680 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2681 dev_name(dev), __func__, retval);
2682 }
2683
2684 /* have the class specific function add its stuff */
2685 if (dev->class && dev->class->dev_uevent) {
2686 retval = dev->class->dev_uevent(dev, env);
2687 if (retval)
2688 pr_debug("device: '%s': %s: class uevent() "
2689 "returned %d\n", dev_name(dev),
2690 __func__, retval);
2691 }
2692
2693 /* have the device type specific function add its stuff */
2694 if (dev->type && dev->type->uevent) {
2695 retval = dev->type->uevent(dev, env);
2696 if (retval)
2697 pr_debug("device: '%s': %s: dev_type uevent() "
2698 "returned %d\n", dev_name(dev),
2699 __func__, retval);
2700 }
2701
2702 return retval;
2703}
2704
2705static const struct kset_uevent_ops device_uevent_ops = {
2706 .filter = dev_uevent_filter,
2707 .name = dev_uevent_name,
2708 .uevent = dev_uevent,
2709};
2710
2711static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2712 char *buf)
2713{
2714 struct kobject *top_kobj;
2715 struct kset *kset;
2716 struct kobj_uevent_env *env = NULL;
2717 int i;
2718 int len = 0;
2719 int retval;
2720
2721 /* search the kset, the device belongs to */
2722 top_kobj = &dev->kobj;
2723 while (!top_kobj->kset && top_kobj->parent)
2724 top_kobj = top_kobj->parent;
2725 if (!top_kobj->kset)
2726 goto out;
2727
2728 kset = top_kobj->kset;
2729 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2730 goto out;
2731
2732 /* respect filter */
2733 if (kset->uevent_ops && kset->uevent_ops->filter)
2734 if (!kset->uevent_ops->filter(&dev->kobj))
2735 goto out;
2736
2737 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2738 if (!env)
2739 return -ENOMEM;
2740
2741 /* let the kset specific function add its keys */
2742 retval = kset->uevent_ops->uevent(&dev->kobj, env);
2743 if (retval)
2744 goto out;
2745
2746 /* copy keys to file */
2747 for (i = 0; i < env->envp_idx; i++)
2748 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2749out:
2750 kfree(env);
2751 return len;
2752}
2753
2754static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2755 const char *buf, size_t count)
2756{
2757 int rc;
2758
2759 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2760
2761 if (rc) {
2762 dev_err(dev, "uevent: failed to send synthetic uevent: %d\n", rc);
2763 return rc;
2764 }
2765
2766 return count;
2767}
2768static DEVICE_ATTR_RW(uevent);
2769
2770static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2771 char *buf)
2772{
2773 bool val;
2774
2775 device_lock(dev);
2776 val = !dev->offline;
2777 device_unlock(dev);
2778 return sysfs_emit(buf, "%u\n", val);
2779}
2780
2781static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2782 const char *buf, size_t count)
2783{
2784 bool val;
2785 int ret;
2786
2787 ret = kstrtobool(buf, &val);
2788 if (ret < 0)
2789 return ret;
2790
2791 ret = lock_device_hotplug_sysfs();
2792 if (ret)
2793 return ret;
2794
2795 ret = val ? device_online(dev) : device_offline(dev);
2796 unlock_device_hotplug();
2797 return ret < 0 ? ret : count;
2798}
2799static DEVICE_ATTR_RW(online);
2800
2801static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2802 char *buf)
2803{
2804 const char *loc;
2805
2806 switch (dev->removable) {
2807 case DEVICE_REMOVABLE:
2808 loc = "removable";
2809 break;
2810 case DEVICE_FIXED:
2811 loc = "fixed";
2812 break;
2813 default:
2814 loc = "unknown";
2815 }
2816 return sysfs_emit(buf, "%s\n", loc);
2817}
2818static DEVICE_ATTR_RO(removable);
2819
2820int device_add_groups(struct device *dev, const struct attribute_group **groups)
2821{
2822 return sysfs_create_groups(&dev->kobj, groups);
2823}
2824EXPORT_SYMBOL_GPL(device_add_groups);
2825
2826void device_remove_groups(struct device *dev,
2827 const struct attribute_group **groups)
2828{
2829 sysfs_remove_groups(&dev->kobj, groups);
2830}
2831EXPORT_SYMBOL_GPL(device_remove_groups);
2832
2833union device_attr_group_devres {
2834 const struct attribute_group *group;
2835 const struct attribute_group **groups;
2836};
2837
2838static void devm_attr_group_remove(struct device *dev, void *res)
2839{
2840 union device_attr_group_devres *devres = res;
2841 const struct attribute_group *group = devres->group;
2842
2843 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2844 sysfs_remove_group(&dev->kobj, group);
2845}
2846
2847static void devm_attr_groups_remove(struct device *dev, void *res)
2848{
2849 union device_attr_group_devres *devres = res;
2850 const struct attribute_group **groups = devres->groups;
2851
2852 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2853 sysfs_remove_groups(&dev->kobj, groups);
2854}
2855
2856/**
2857 * devm_device_add_group - given a device, create a managed attribute group
2858 * @dev: The device to create the group for
2859 * @grp: The attribute group to create
2860 *
2861 * This function creates a group for the first time. It will explicitly
2862 * warn and error if any of the attribute files being created already exist.
2863 *
2864 * Returns 0 on success or error code on failure.
2865 */
2866int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2867{
2868 union device_attr_group_devres *devres;
2869 int error;
2870
2871 devres = devres_alloc(devm_attr_group_remove,
2872 sizeof(*devres), GFP_KERNEL);
2873 if (!devres)
2874 return -ENOMEM;
2875
2876 error = sysfs_create_group(&dev->kobj, grp);
2877 if (error) {
2878 devres_free(devres);
2879 return error;
2880 }
2881
2882 devres->group = grp;
2883 devres_add(dev, devres);
2884 return 0;
2885}
2886EXPORT_SYMBOL_GPL(devm_device_add_group);
2887
2888/**
2889 * devm_device_add_groups - create a bunch of managed attribute groups
2890 * @dev: The device to create the group for
2891 * @groups: The attribute groups to create, NULL terminated
2892 *
2893 * This function creates a bunch of managed attribute groups. If an error
2894 * occurs when creating a group, all previously created groups will be
2895 * removed, unwinding everything back to the original state when this
2896 * function was called. It will explicitly warn and error if any of the
2897 * attribute files being created already exist.
2898 *
2899 * Returns 0 on success or error code from sysfs_create_group on failure.
2900 */
2901int devm_device_add_groups(struct device *dev,
2902 const struct attribute_group **groups)
2903{
2904 union device_attr_group_devres *devres;
2905 int error;
2906
2907 devres = devres_alloc(devm_attr_groups_remove,
2908 sizeof(*devres), GFP_KERNEL);
2909 if (!devres)
2910 return -ENOMEM;
2911
2912 error = sysfs_create_groups(&dev->kobj, groups);
2913 if (error) {
2914 devres_free(devres);
2915 return error;
2916 }
2917
2918 devres->groups = groups;
2919 devres_add(dev, devres);
2920 return 0;
2921}
2922EXPORT_SYMBOL_GPL(devm_device_add_groups);
2923
2924static int device_add_attrs(struct device *dev)
2925{
2926 const struct class *class = dev->class;
2927 const struct device_type *type = dev->type;
2928 int error;
2929
2930 if (class) {
2931 error = device_add_groups(dev, class->dev_groups);
2932 if (error)
2933 return error;
2934 }
2935
2936 if (type) {
2937 error = device_add_groups(dev, type->groups);
2938 if (error)
2939 goto err_remove_class_groups;
2940 }
2941
2942 error = device_add_groups(dev, dev->groups);
2943 if (error)
2944 goto err_remove_type_groups;
2945
2946 if (device_supports_offline(dev) && !dev->offline_disabled) {
2947 error = device_create_file(dev, &dev_attr_online);
2948 if (error)
2949 goto err_remove_dev_groups;
2950 }
2951
2952 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2953 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2954 if (error)
2955 goto err_remove_dev_online;
2956 }
2957
2958 if (dev_removable_is_valid(dev)) {
2959 error = device_create_file(dev, &dev_attr_removable);
2960 if (error)
2961 goto err_remove_dev_waiting_for_supplier;
2962 }
2963
2964 if (dev_add_physical_location(dev)) {
2965 error = device_add_group(dev,
2966 &dev_attr_physical_location_group);
2967 if (error)
2968 goto err_remove_dev_removable;
2969 }
2970
2971 return 0;
2972
2973 err_remove_dev_removable:
2974 device_remove_file(dev, &dev_attr_removable);
2975 err_remove_dev_waiting_for_supplier:
2976 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2977 err_remove_dev_online:
2978 device_remove_file(dev, &dev_attr_online);
2979 err_remove_dev_groups:
2980 device_remove_groups(dev, dev->groups);
2981 err_remove_type_groups:
2982 if (type)
2983 device_remove_groups(dev, type->groups);
2984 err_remove_class_groups:
2985 if (class)
2986 device_remove_groups(dev, class->dev_groups);
2987
2988 return error;
2989}
2990
2991static void device_remove_attrs(struct device *dev)
2992{
2993 const struct class *class = dev->class;
2994 const struct device_type *type = dev->type;
2995
2996 if (dev->physical_location) {
2997 device_remove_group(dev, &dev_attr_physical_location_group);
2998 kfree(dev->physical_location);
2999 }
3000
3001 device_remove_file(dev, &dev_attr_removable);
3002 device_remove_file(dev, &dev_attr_waiting_for_supplier);
3003 device_remove_file(dev, &dev_attr_online);
3004 device_remove_groups(dev, dev->groups);
3005
3006 if (type)
3007 device_remove_groups(dev, type->groups);
3008
3009 if (class)
3010 device_remove_groups(dev, class->dev_groups);
3011}
3012
3013static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
3014 char *buf)
3015{
3016 return print_dev_t(buf, dev->devt);
3017}
3018static DEVICE_ATTR_RO(dev);
3019
3020/* /sys/devices/ */
3021struct kset *devices_kset;
3022
3023/**
3024 * devices_kset_move_before - Move device in the devices_kset's list.
3025 * @deva: Device to move.
3026 * @devb: Device @deva should come before.
3027 */
3028static void devices_kset_move_before(struct device *deva, struct device *devb)
3029{
3030 if (!devices_kset)
3031 return;
3032 pr_debug("devices_kset: Moving %s before %s\n",
3033 dev_name(deva), dev_name(devb));
3034 spin_lock(&devices_kset->list_lock);
3035 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
3036 spin_unlock(&devices_kset->list_lock);
3037}
3038
3039/**
3040 * devices_kset_move_after - Move device in the devices_kset's list.
3041 * @deva: Device to move
3042 * @devb: Device @deva should come after.
3043 */
3044static void devices_kset_move_after(struct device *deva, struct device *devb)
3045{
3046 if (!devices_kset)
3047 return;
3048 pr_debug("devices_kset: Moving %s after %s\n",
3049 dev_name(deva), dev_name(devb));
3050 spin_lock(&devices_kset->list_lock);
3051 list_move(&deva->kobj.entry, &devb->kobj.entry);
3052 spin_unlock(&devices_kset->list_lock);
3053}
3054
3055/**
3056 * devices_kset_move_last - move the device to the end of devices_kset's list.
3057 * @dev: device to move
3058 */
3059void devices_kset_move_last(struct device *dev)
3060{
3061 if (!devices_kset)
3062 return;
3063 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
3064 spin_lock(&devices_kset->list_lock);
3065 list_move_tail(&dev->kobj.entry, &devices_kset->list);
3066 spin_unlock(&devices_kset->list_lock);
3067}
3068
3069/**
3070 * device_create_file - create sysfs attribute file for device.
3071 * @dev: device.
3072 * @attr: device attribute descriptor.
3073 */
3074int device_create_file(struct device *dev,
3075 const struct device_attribute *attr)
3076{
3077 int error = 0;
3078
3079 if (dev) {
3080 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
3081 "Attribute %s: write permission without 'store'\n",
3082 attr->attr.name);
3083 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
3084 "Attribute %s: read permission without 'show'\n",
3085 attr->attr.name);
3086 error = sysfs_create_file(&dev->kobj, &attr->attr);
3087 }
3088
3089 return error;
3090}
3091EXPORT_SYMBOL_GPL(device_create_file);
3092
3093/**
3094 * device_remove_file - remove sysfs attribute file.
3095 * @dev: device.
3096 * @attr: device attribute descriptor.
3097 */
3098void device_remove_file(struct device *dev,
3099 const struct device_attribute *attr)
3100{
3101 if (dev)
3102 sysfs_remove_file(&dev->kobj, &attr->attr);
3103}
3104EXPORT_SYMBOL_GPL(device_remove_file);
3105
3106/**
3107 * device_remove_file_self - remove sysfs attribute file from its own method.
3108 * @dev: device.
3109 * @attr: device attribute descriptor.
3110 *
3111 * See kernfs_remove_self() for details.
3112 */
3113bool device_remove_file_self(struct device *dev,
3114 const struct device_attribute *attr)
3115{
3116 if (dev)
3117 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
3118 else
3119 return false;
3120}
3121EXPORT_SYMBOL_GPL(device_remove_file_self);
3122
3123/**
3124 * device_create_bin_file - create sysfs binary attribute file for device.
3125 * @dev: device.
3126 * @attr: device binary attribute descriptor.
3127 */
3128int device_create_bin_file(struct device *dev,
3129 const struct bin_attribute *attr)
3130{
3131 int error = -EINVAL;
3132 if (dev)
3133 error = sysfs_create_bin_file(&dev->kobj, attr);
3134 return error;
3135}
3136EXPORT_SYMBOL_GPL(device_create_bin_file);
3137
3138/**
3139 * device_remove_bin_file - remove sysfs binary attribute file
3140 * @dev: device.
3141 * @attr: device binary attribute descriptor.
3142 */
3143void device_remove_bin_file(struct device *dev,
3144 const struct bin_attribute *attr)
3145{
3146 if (dev)
3147 sysfs_remove_bin_file(&dev->kobj, attr);
3148}
3149EXPORT_SYMBOL_GPL(device_remove_bin_file);
3150
3151static void klist_children_get(struct klist_node *n)
3152{
3153 struct device_private *p = to_device_private_parent(n);
3154 struct device *dev = p->device;
3155
3156 get_device(dev);
3157}
3158
3159static void klist_children_put(struct klist_node *n)
3160{
3161 struct device_private *p = to_device_private_parent(n);
3162 struct device *dev = p->device;
3163
3164 put_device(dev);
3165}
3166
3167/**
3168 * device_initialize - init device structure.
3169 * @dev: device.
3170 *
3171 * This prepares the device for use by other layers by initializing
3172 * its fields.
3173 * It is the first half of device_register(), if called by
3174 * that function, though it can also be called separately, so one
3175 * may use @dev's fields. In particular, get_device()/put_device()
3176 * may be used for reference counting of @dev after calling this
3177 * function.
3178 *
3179 * All fields in @dev must be initialized by the caller to 0, except
3180 * for those explicitly set to some other value. The simplest
3181 * approach is to use kzalloc() to allocate the structure containing
3182 * @dev.
3183 *
3184 * NOTE: Use put_device() to give up your reference instead of freeing
3185 * @dev directly once you have called this function.
3186 */
3187void device_initialize(struct device *dev)
3188{
3189 dev->kobj.kset = devices_kset;
3190 kobject_init(&dev->kobj, &device_ktype);
3191 INIT_LIST_HEAD(&dev->dma_pools);
3192 mutex_init(&dev->mutex);
3193 lockdep_set_novalidate_class(&dev->mutex);
3194 spin_lock_init(&dev->devres_lock);
3195 INIT_LIST_HEAD(&dev->devres_head);
3196 device_pm_init(dev);
3197 set_dev_node(dev, NUMA_NO_NODE);
3198 INIT_LIST_HEAD(&dev->links.consumers);
3199 INIT_LIST_HEAD(&dev->links.suppliers);
3200 INIT_LIST_HEAD(&dev->links.defer_sync);
3201 dev->links.status = DL_DEV_NO_DRIVER;
3202#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
3203 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
3204 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
3205 dev->dma_coherent = dma_default_coherent;
3206#endif
3207 swiotlb_dev_init(dev);
3208}
3209EXPORT_SYMBOL_GPL(device_initialize);
3210
3211struct kobject *virtual_device_parent(struct device *dev)
3212{
3213 static struct kobject *virtual_dir = NULL;
3214
3215 if (!virtual_dir)
3216 virtual_dir = kobject_create_and_add("virtual",
3217 &devices_kset->kobj);
3218
3219 return virtual_dir;
3220}
3221
3222struct class_dir {
3223 struct kobject kobj;
3224 const struct class *class;
3225};
3226
3227#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
3228
3229static void class_dir_release(struct kobject *kobj)
3230{
3231 struct class_dir *dir = to_class_dir(kobj);
3232 kfree(dir);
3233}
3234
3235static const
3236struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *kobj)
3237{
3238 const struct class_dir *dir = to_class_dir(kobj);
3239 return dir->class->ns_type;
3240}
3241
3242static const struct kobj_type class_dir_ktype = {
3243 .release = class_dir_release,
3244 .sysfs_ops = &kobj_sysfs_ops,
3245 .child_ns_type = class_dir_child_ns_type
3246};
3247
3248static struct kobject *class_dir_create_and_add(struct subsys_private *sp,
3249 struct kobject *parent_kobj)
3250{
3251 struct class_dir *dir;
3252 int retval;
3253
3254 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
3255 if (!dir)
3256 return ERR_PTR(-ENOMEM);
3257
3258 dir->class = sp->class;
3259 kobject_init(&dir->kobj, &class_dir_ktype);
3260
3261 dir->kobj.kset = &sp->glue_dirs;
3262
3263 retval = kobject_add(&dir->kobj, parent_kobj, "%s", sp->class->name);
3264 if (retval < 0) {
3265 kobject_put(&dir->kobj);
3266 return ERR_PTR(retval);
3267 }
3268 return &dir->kobj;
3269}
3270
3271static DEFINE_MUTEX(gdp_mutex);
3272
3273static struct kobject *get_device_parent(struct device *dev,
3274 struct device *parent)
3275{
3276 struct subsys_private *sp = class_to_subsys(dev->class);
3277 struct kobject *kobj = NULL;
3278
3279 if (sp) {
3280 struct kobject *parent_kobj;
3281 struct kobject *k;
3282
3283 /*
3284 * If we have no parent, we live in "virtual".
3285 * Class-devices with a non class-device as parent, live
3286 * in a "glue" directory to prevent namespace collisions.
3287 */
3288 if (parent == NULL)
3289 parent_kobj = virtual_device_parent(dev);
3290 else if (parent->class && !dev->class->ns_type) {
3291 subsys_put(sp);
3292 return &parent->kobj;
3293 } else {
3294 parent_kobj = &parent->kobj;
3295 }
3296
3297 mutex_lock(&gdp_mutex);
3298
3299 /* find our class-directory at the parent and reference it */
3300 spin_lock(&sp->glue_dirs.list_lock);
3301 list_for_each_entry(k, &sp->glue_dirs.list, entry)
3302 if (k->parent == parent_kobj) {
3303 kobj = kobject_get(k);
3304 break;
3305 }
3306 spin_unlock(&sp->glue_dirs.list_lock);
3307 if (kobj) {
3308 mutex_unlock(&gdp_mutex);
3309 subsys_put(sp);
3310 return kobj;
3311 }
3312
3313 /* or create a new class-directory at the parent device */
3314 k = class_dir_create_and_add(sp, parent_kobj);
3315 /* do not emit an uevent for this simple "glue" directory */
3316 mutex_unlock(&gdp_mutex);
3317 subsys_put(sp);
3318 return k;
3319 }
3320
3321 /* subsystems can specify a default root directory for their devices */
3322 if (!parent && dev->bus) {
3323 struct device *dev_root = bus_get_dev_root(dev->bus);
3324
3325 if (dev_root) {
3326 kobj = &dev_root->kobj;
3327 put_device(dev_root);
3328 return kobj;
3329 }
3330 }
3331
3332 if (parent)
3333 return &parent->kobj;
3334 return NULL;
3335}
3336
3337static inline bool live_in_glue_dir(struct kobject *kobj,
3338 struct device *dev)
3339{
3340 struct subsys_private *sp;
3341 bool retval;
3342
3343 if (!kobj || !dev->class)
3344 return false;
3345
3346 sp = class_to_subsys(dev->class);
3347 if (!sp)
3348 return false;
3349
3350 if (kobj->kset == &sp->glue_dirs)
3351 retval = true;
3352 else
3353 retval = false;
3354
3355 subsys_put(sp);
3356 return retval;
3357}
3358
3359static inline struct kobject *get_glue_dir(struct device *dev)
3360{
3361 return dev->kobj.parent;
3362}
3363
3364/**
3365 * kobject_has_children - Returns whether a kobject has children.
3366 * @kobj: the object to test
3367 *
3368 * This will return whether a kobject has other kobjects as children.
3369 *
3370 * It does NOT account for the presence of attribute files, only sub
3371 * directories. It also assumes there is no concurrent addition or
3372 * removal of such children, and thus relies on external locking.
3373 */
3374static inline bool kobject_has_children(struct kobject *kobj)
3375{
3376 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
3377
3378 return kobj->sd && kobj->sd->dir.subdirs;
3379}
3380
3381/*
3382 * make sure cleaning up dir as the last step, we need to make
3383 * sure .release handler of kobject is run with holding the
3384 * global lock
3385 */
3386static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3387{
3388 unsigned int ref;
3389
3390 /* see if we live in a "glue" directory */
3391 if (!live_in_glue_dir(glue_dir, dev))
3392 return;
3393
3394 mutex_lock(&gdp_mutex);
3395 /**
3396 * There is a race condition between removing glue directory
3397 * and adding a new device under the glue directory.
3398 *
3399 * CPU1: CPU2:
3400 *
3401 * device_add()
3402 * get_device_parent()
3403 * class_dir_create_and_add()
3404 * kobject_add_internal()
3405 * create_dir() // create glue_dir
3406 *
3407 * device_add()
3408 * get_device_parent()
3409 * kobject_get() // get glue_dir
3410 *
3411 * device_del()
3412 * cleanup_glue_dir()
3413 * kobject_del(glue_dir)
3414 *
3415 * kobject_add()
3416 * kobject_add_internal()
3417 * create_dir() // in glue_dir
3418 * sysfs_create_dir_ns()
3419 * kernfs_create_dir_ns(sd)
3420 *
3421 * sysfs_remove_dir() // glue_dir->sd=NULL
3422 * sysfs_put() // free glue_dir->sd
3423 *
3424 * // sd is freed
3425 * kernfs_new_node(sd)
3426 * kernfs_get(glue_dir)
3427 * kernfs_add_one()
3428 * kernfs_put()
3429 *
3430 * Before CPU1 remove last child device under glue dir, if CPU2 add
3431 * a new device under glue dir, the glue_dir kobject reference count
3432 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3433 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3434 * and sysfs_put(). This result in glue_dir->sd is freed.
3435 *
3436 * Then the CPU2 will see a stale "empty" but still potentially used
3437 * glue dir around in kernfs_new_node().
3438 *
3439 * In order to avoid this happening, we also should make sure that
3440 * kernfs_node for glue_dir is released in CPU1 only when refcount
3441 * for glue_dir kobj is 1.
3442 */
3443 ref = kref_read(&glue_dir->kref);
3444 if (!kobject_has_children(glue_dir) && !--ref)
3445 kobject_del(glue_dir);
3446 kobject_put(glue_dir);
3447 mutex_unlock(&gdp_mutex);
3448}
3449
3450static int device_add_class_symlinks(struct device *dev)
3451{
3452 struct device_node *of_node = dev_of_node(dev);
3453 struct subsys_private *sp;
3454 int error;
3455
3456 if (of_node) {
3457 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3458 if (error)
3459 dev_warn(dev, "Error %d creating of_node link\n",error);
3460 /* An error here doesn't warrant bringing down the device */
3461 }
3462
3463 sp = class_to_subsys(dev->class);
3464 if (!sp)
3465 return 0;
3466
3467 error = sysfs_create_link(&dev->kobj, &sp->subsys.kobj, "subsystem");
3468 if (error)
3469 goto out_devnode;
3470
3471 if (dev->parent && device_is_not_partition(dev)) {
3472 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3473 "device");
3474 if (error)
3475 goto out_subsys;
3476 }
3477
3478 /* link in the class directory pointing to the device */
3479 error = sysfs_create_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3480 if (error)
3481 goto out_device;
3482 goto exit;
3483
3484out_device:
3485 sysfs_remove_link(&dev->kobj, "device");
3486out_subsys:
3487 sysfs_remove_link(&dev->kobj, "subsystem");
3488out_devnode:
3489 sysfs_remove_link(&dev->kobj, "of_node");
3490exit:
3491 subsys_put(sp);
3492 return error;
3493}
3494
3495static void device_remove_class_symlinks(struct device *dev)
3496{
3497 struct subsys_private *sp = class_to_subsys(dev->class);
3498
3499 if (dev_of_node(dev))
3500 sysfs_remove_link(&dev->kobj, "of_node");
3501
3502 if (!sp)
3503 return;
3504
3505 if (dev->parent && device_is_not_partition(dev))
3506 sysfs_remove_link(&dev->kobj, "device");
3507 sysfs_remove_link(&dev->kobj, "subsystem");
3508 sysfs_delete_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3509 subsys_put(sp);
3510}
3511
3512/**
3513 * dev_set_name - set a device name
3514 * @dev: device
3515 * @fmt: format string for the device's name
3516 */
3517int dev_set_name(struct device *dev, const char *fmt, ...)
3518{
3519 va_list vargs;
3520 int err;
3521
3522 va_start(vargs, fmt);
3523 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3524 va_end(vargs);
3525 return err;
3526}
3527EXPORT_SYMBOL_GPL(dev_set_name);
3528
3529/* select a /sys/dev/ directory for the device */
3530static struct kobject *device_to_dev_kobj(struct device *dev)
3531{
3532 if (is_blockdev(dev))
3533 return sysfs_dev_block_kobj;
3534 else
3535 return sysfs_dev_char_kobj;
3536}
3537
3538static int device_create_sys_dev_entry(struct device *dev)
3539{
3540 struct kobject *kobj = device_to_dev_kobj(dev);
3541 int error = 0;
3542 char devt_str[15];
3543
3544 if (kobj) {
3545 format_dev_t(devt_str, dev->devt);
3546 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3547 }
3548
3549 return error;
3550}
3551
3552static void device_remove_sys_dev_entry(struct device *dev)
3553{
3554 struct kobject *kobj = device_to_dev_kobj(dev);
3555 char devt_str[15];
3556
3557 if (kobj) {
3558 format_dev_t(devt_str, dev->devt);
3559 sysfs_remove_link(kobj, devt_str);
3560 }
3561}
3562
3563static int device_private_init(struct device *dev)
3564{
3565 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3566 if (!dev->p)
3567 return -ENOMEM;
3568 dev->p->device = dev;
3569 klist_init(&dev->p->klist_children, klist_children_get,
3570 klist_children_put);
3571 INIT_LIST_HEAD(&dev->p->deferred_probe);
3572 return 0;
3573}
3574
3575/**
3576 * device_add - add device to device hierarchy.
3577 * @dev: device.
3578 *
3579 * This is part 2 of device_register(), though may be called
3580 * separately _iff_ device_initialize() has been called separately.
3581 *
3582 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3583 * to the global and sibling lists for the device, then
3584 * adds it to the other relevant subsystems of the driver model.
3585 *
3586 * Do not call this routine or device_register() more than once for
3587 * any device structure. The driver model core is not designed to work
3588 * with devices that get unregistered and then spring back to life.
3589 * (Among other things, it's very hard to guarantee that all references
3590 * to the previous incarnation of @dev have been dropped.) Allocate
3591 * and register a fresh new struct device instead.
3592 *
3593 * NOTE: _Never_ directly free @dev after calling this function, even
3594 * if it returned an error! Always use put_device() to give up your
3595 * reference instead.
3596 *
3597 * Rule of thumb is: if device_add() succeeds, you should call
3598 * device_del() when you want to get rid of it. If device_add() has
3599 * *not* succeeded, use *only* put_device() to drop the reference
3600 * count.
3601 */
3602int device_add(struct device *dev)
3603{
3604 struct subsys_private *sp;
3605 struct device *parent;
3606 struct kobject *kobj;
3607 struct class_interface *class_intf;
3608 int error = -EINVAL;
3609 struct kobject *glue_dir = NULL;
3610
3611 dev = get_device(dev);
3612 if (!dev)
3613 goto done;
3614
3615 if (!dev->p) {
3616 error = device_private_init(dev);
3617 if (error)
3618 goto done;
3619 }
3620
3621 /*
3622 * for statically allocated devices, which should all be converted
3623 * some day, we need to initialize the name. We prevent reading back
3624 * the name, and force the use of dev_name()
3625 */
3626 if (dev->init_name) {
3627 error = dev_set_name(dev, "%s", dev->init_name);
3628 dev->init_name = NULL;
3629 }
3630
3631 if (dev_name(dev))
3632 error = 0;
3633 /* subsystems can specify simple device enumeration */
3634 else if (dev->bus && dev->bus->dev_name)
3635 error = dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3636 else
3637 error = -EINVAL;
3638 if (error)
3639 goto name_error;
3640
3641 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3642
3643 parent = get_device(dev->parent);
3644 kobj = get_device_parent(dev, parent);
3645 if (IS_ERR(kobj)) {
3646 error = PTR_ERR(kobj);
3647 goto parent_error;
3648 }
3649 if (kobj)
3650 dev->kobj.parent = kobj;
3651
3652 /* use parent numa_node */
3653 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3654 set_dev_node(dev, dev_to_node(parent));
3655
3656 /* first, register with generic layer. */
3657 /* we require the name to be set before, and pass NULL */
3658 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3659 if (error) {
3660 glue_dir = kobj;
3661 goto Error;
3662 }
3663
3664 /* notify platform of device entry */
3665 device_platform_notify(dev);
3666
3667 error = device_create_file(dev, &dev_attr_uevent);
3668 if (error)
3669 goto attrError;
3670
3671 error = device_add_class_symlinks(dev);
3672 if (error)
3673 goto SymlinkError;
3674 error = device_add_attrs(dev);
3675 if (error)
3676 goto AttrsError;
3677 error = bus_add_device(dev);
3678 if (error)
3679 goto BusError;
3680 error = dpm_sysfs_add(dev);
3681 if (error)
3682 goto DPMError;
3683 device_pm_add(dev);
3684
3685 if (MAJOR(dev->devt)) {
3686 error = device_create_file(dev, &dev_attr_dev);
3687 if (error)
3688 goto DevAttrError;
3689
3690 error = device_create_sys_dev_entry(dev);
3691 if (error)
3692 goto SysEntryError;
3693
3694 devtmpfs_create_node(dev);
3695 }
3696
3697 /* Notify clients of device addition. This call must come
3698 * after dpm_sysfs_add() and before kobject_uevent().
3699 */
3700 bus_notify(dev, BUS_NOTIFY_ADD_DEVICE);
3701 kobject_uevent(&dev->kobj, KOBJ_ADD);
3702
3703 /*
3704 * Check if any of the other devices (consumers) have been waiting for
3705 * this device (supplier) to be added so that they can create a device
3706 * link to it.
3707 *
3708 * This needs to happen after device_pm_add() because device_link_add()
3709 * requires the supplier be registered before it's called.
3710 *
3711 * But this also needs to happen before bus_probe_device() to make sure
3712 * waiting consumers can link to it before the driver is bound to the
3713 * device and the driver sync_state callback is called for this device.
3714 */
3715 if (dev->fwnode && !dev->fwnode->dev) {
3716 dev->fwnode->dev = dev;
3717 fw_devlink_link_device(dev);
3718 }
3719
3720 bus_probe_device(dev);
3721
3722 /*
3723 * If all driver registration is done and a newly added device doesn't
3724 * match with any driver, don't block its consumers from probing in
3725 * case the consumer device is able to operate without this supplier.
3726 */
3727 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3728 fw_devlink_unblock_consumers(dev);
3729
3730 if (parent)
3731 klist_add_tail(&dev->p->knode_parent,
3732 &parent->p->klist_children);
3733
3734 sp = class_to_subsys(dev->class);
3735 if (sp) {
3736 mutex_lock(&sp->mutex);
3737 /* tie the class to the device */
3738 klist_add_tail(&dev->p->knode_class, &sp->klist_devices);
3739
3740 /* notify any interfaces that the device is here */
3741 list_for_each_entry(class_intf, &sp->interfaces, node)
3742 if (class_intf->add_dev)
3743 class_intf->add_dev(dev);
3744 mutex_unlock(&sp->mutex);
3745 subsys_put(sp);
3746 }
3747done:
3748 put_device(dev);
3749 return error;
3750 SysEntryError:
3751 if (MAJOR(dev->devt))
3752 device_remove_file(dev, &dev_attr_dev);
3753 DevAttrError:
3754 device_pm_remove(dev);
3755 dpm_sysfs_remove(dev);
3756 DPMError:
3757 dev->driver = NULL;
3758 bus_remove_device(dev);
3759 BusError:
3760 device_remove_attrs(dev);
3761 AttrsError:
3762 device_remove_class_symlinks(dev);
3763 SymlinkError:
3764 device_remove_file(dev, &dev_attr_uevent);
3765 attrError:
3766 device_platform_notify_remove(dev);
3767 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3768 glue_dir = get_glue_dir(dev);
3769 kobject_del(&dev->kobj);
3770 Error:
3771 cleanup_glue_dir(dev, glue_dir);
3772parent_error:
3773 put_device(parent);
3774name_error:
3775 kfree(dev->p);
3776 dev->p = NULL;
3777 goto done;
3778}
3779EXPORT_SYMBOL_GPL(device_add);
3780
3781/**
3782 * device_register - register a device with the system.
3783 * @dev: pointer to the device structure
3784 *
3785 * This happens in two clean steps - initialize the device
3786 * and add it to the system. The two steps can be called
3787 * separately, but this is the easiest and most common.
3788 * I.e. you should only call the two helpers separately if
3789 * have a clearly defined need to use and refcount the device
3790 * before it is added to the hierarchy.
3791 *
3792 * For more information, see the kerneldoc for device_initialize()
3793 * and device_add().
3794 *
3795 * NOTE: _Never_ directly free @dev after calling this function, even
3796 * if it returned an error! Always use put_device() to give up the
3797 * reference initialized in this function instead.
3798 */
3799int device_register(struct device *dev)
3800{
3801 device_initialize(dev);
3802 return device_add(dev);
3803}
3804EXPORT_SYMBOL_GPL(device_register);
3805
3806/**
3807 * get_device - increment reference count for device.
3808 * @dev: device.
3809 *
3810 * This simply forwards the call to kobject_get(), though
3811 * we do take care to provide for the case that we get a NULL
3812 * pointer passed in.
3813 */
3814struct device *get_device(struct device *dev)
3815{
3816 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3817}
3818EXPORT_SYMBOL_GPL(get_device);
3819
3820/**
3821 * put_device - decrement reference count.
3822 * @dev: device in question.
3823 */
3824void put_device(struct device *dev)
3825{
3826 /* might_sleep(); */
3827 if (dev)
3828 kobject_put(&dev->kobj);
3829}
3830EXPORT_SYMBOL_GPL(put_device);
3831
3832bool kill_device(struct device *dev)
3833{
3834 /*
3835 * Require the device lock and set the "dead" flag to guarantee that
3836 * the update behavior is consistent with the other bitfields near
3837 * it and that we cannot have an asynchronous probe routine trying
3838 * to run while we are tearing out the bus/class/sysfs from
3839 * underneath the device.
3840 */
3841 device_lock_assert(dev);
3842
3843 if (dev->p->dead)
3844 return false;
3845 dev->p->dead = true;
3846 return true;
3847}
3848EXPORT_SYMBOL_GPL(kill_device);
3849
3850/**
3851 * device_del - delete device from system.
3852 * @dev: device.
3853 *
3854 * This is the first part of the device unregistration
3855 * sequence. This removes the device from the lists we control
3856 * from here, has it removed from the other driver model
3857 * subsystems it was added to in device_add(), and removes it
3858 * from the kobject hierarchy.
3859 *
3860 * NOTE: this should be called manually _iff_ device_add() was
3861 * also called manually.
3862 */
3863void device_del(struct device *dev)
3864{
3865 struct subsys_private *sp;
3866 struct device *parent = dev->parent;
3867 struct kobject *glue_dir = NULL;
3868 struct class_interface *class_intf;
3869 unsigned int noio_flag;
3870
3871 device_lock(dev);
3872 kill_device(dev);
3873 device_unlock(dev);
3874
3875 if (dev->fwnode && dev->fwnode->dev == dev)
3876 dev->fwnode->dev = NULL;
3877
3878 /* Notify clients of device removal. This call must come
3879 * before dpm_sysfs_remove().
3880 */
3881 noio_flag = memalloc_noio_save();
3882 bus_notify(dev, BUS_NOTIFY_DEL_DEVICE);
3883
3884 dpm_sysfs_remove(dev);
3885 if (parent)
3886 klist_del(&dev->p->knode_parent);
3887 if (MAJOR(dev->devt)) {
3888 devtmpfs_delete_node(dev);
3889 device_remove_sys_dev_entry(dev);
3890 device_remove_file(dev, &dev_attr_dev);
3891 }
3892
3893 sp = class_to_subsys(dev->class);
3894 if (sp) {
3895 device_remove_class_symlinks(dev);
3896
3897 mutex_lock(&sp->mutex);
3898 /* notify any interfaces that the device is now gone */
3899 list_for_each_entry(class_intf, &sp->interfaces, node)
3900 if (class_intf->remove_dev)
3901 class_intf->remove_dev(dev);
3902 /* remove the device from the class list */
3903 klist_del(&dev->p->knode_class);
3904 mutex_unlock(&sp->mutex);
3905 subsys_put(sp);
3906 }
3907 device_remove_file(dev, &dev_attr_uevent);
3908 device_remove_attrs(dev);
3909 bus_remove_device(dev);
3910 device_pm_remove(dev);
3911 driver_deferred_probe_del(dev);
3912 device_platform_notify_remove(dev);
3913 device_links_purge(dev);
3914
3915 /*
3916 * If a device does not have a driver attached, we need to clean
3917 * up any managed resources. We do this in device_release(), but
3918 * it's never called (and we leak the device) if a managed
3919 * resource holds a reference to the device. So release all
3920 * managed resources here, like we do in driver_detach(). We
3921 * still need to do so again in device_release() in case someone
3922 * adds a new resource after this point, though.
3923 */
3924 devres_release_all(dev);
3925
3926 bus_notify(dev, BUS_NOTIFY_REMOVED_DEVICE);
3927 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3928 glue_dir = get_glue_dir(dev);
3929 kobject_del(&dev->kobj);
3930 cleanup_glue_dir(dev, glue_dir);
3931 memalloc_noio_restore(noio_flag);
3932 put_device(parent);
3933}
3934EXPORT_SYMBOL_GPL(device_del);
3935
3936/**
3937 * device_unregister - unregister device from system.
3938 * @dev: device going away.
3939 *
3940 * We do this in two parts, like we do device_register(). First,
3941 * we remove it from all the subsystems with device_del(), then
3942 * we decrement the reference count via put_device(). If that
3943 * is the final reference count, the device will be cleaned up
3944 * via device_release() above. Otherwise, the structure will
3945 * stick around until the final reference to the device is dropped.
3946 */
3947void device_unregister(struct device *dev)
3948{
3949 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3950 device_del(dev);
3951 put_device(dev);
3952}
3953EXPORT_SYMBOL_GPL(device_unregister);
3954
3955static struct device *prev_device(struct klist_iter *i)
3956{
3957 struct klist_node *n = klist_prev(i);
3958 struct device *dev = NULL;
3959 struct device_private *p;
3960
3961 if (n) {
3962 p = to_device_private_parent(n);
3963 dev = p->device;
3964 }
3965 return dev;
3966}
3967
3968static struct device *next_device(struct klist_iter *i)
3969{
3970 struct klist_node *n = klist_next(i);
3971 struct device *dev = NULL;
3972 struct device_private *p;
3973
3974 if (n) {
3975 p = to_device_private_parent(n);
3976 dev = p->device;
3977 }
3978 return dev;
3979}
3980
3981/**
3982 * device_get_devnode - path of device node file
3983 * @dev: device
3984 * @mode: returned file access mode
3985 * @uid: returned file owner
3986 * @gid: returned file group
3987 * @tmp: possibly allocated string
3988 *
3989 * Return the relative path of a possible device node.
3990 * Non-default names may need to allocate a memory to compose
3991 * a name. This memory is returned in tmp and needs to be
3992 * freed by the caller.
3993 */
3994const char *device_get_devnode(const struct device *dev,
3995 umode_t *mode, kuid_t *uid, kgid_t *gid,
3996 const char **tmp)
3997{
3998 char *s;
3999
4000 *tmp = NULL;
4001
4002 /* the device type may provide a specific name */
4003 if (dev->type && dev->type->devnode)
4004 *tmp = dev->type->devnode(dev, mode, uid, gid);
4005 if (*tmp)
4006 return *tmp;
4007
4008 /* the class may provide a specific name */
4009 if (dev->class && dev->class->devnode)
4010 *tmp = dev->class->devnode(dev, mode);
4011 if (*tmp)
4012 return *tmp;
4013
4014 /* return name without allocation, tmp == NULL */
4015 if (strchr(dev_name(dev), '!') == NULL)
4016 return dev_name(dev);
4017
4018 /* replace '!' in the name with '/' */
4019 s = kstrdup_and_replace(dev_name(dev), '!', '/', GFP_KERNEL);
4020 if (!s)
4021 return NULL;
4022 return *tmp = s;
4023}
4024
4025/**
4026 * device_for_each_child - device child iterator.
4027 * @parent: parent struct device.
4028 * @fn: function to be called for each device.
4029 * @data: data for the callback.
4030 *
4031 * Iterate over @parent's child devices, and call @fn for each,
4032 * passing it @data.
4033 *
4034 * We check the return of @fn each time. If it returns anything
4035 * other than 0, we break out and return that value.
4036 */
4037int device_for_each_child(struct device *parent, void *data,
4038 int (*fn)(struct device *dev, void *data))
4039{
4040 struct klist_iter i;
4041 struct device *child;
4042 int error = 0;
4043
4044 if (!parent->p)
4045 return 0;
4046
4047 klist_iter_init(&parent->p->klist_children, &i);
4048 while (!error && (child = next_device(&i)))
4049 error = fn(child, data);
4050 klist_iter_exit(&i);
4051 return error;
4052}
4053EXPORT_SYMBOL_GPL(device_for_each_child);
4054
4055/**
4056 * device_for_each_child_reverse - device child iterator in reversed order.
4057 * @parent: parent struct device.
4058 * @fn: function to be called for each device.
4059 * @data: data for the callback.
4060 *
4061 * Iterate over @parent's child devices, and call @fn for each,
4062 * passing it @data.
4063 *
4064 * We check the return of @fn each time. If it returns anything
4065 * other than 0, we break out and return that value.
4066 */
4067int device_for_each_child_reverse(struct device *parent, void *data,
4068 int (*fn)(struct device *dev, void *data))
4069{
4070 struct klist_iter i;
4071 struct device *child;
4072 int error = 0;
4073
4074 if (!parent->p)
4075 return 0;
4076
4077 klist_iter_init(&parent->p->klist_children, &i);
4078 while ((child = prev_device(&i)) && !error)
4079 error = fn(child, data);
4080 klist_iter_exit(&i);
4081 return error;
4082}
4083EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
4084
4085/**
4086 * device_find_child - device iterator for locating a particular device.
4087 * @parent: parent struct device
4088 * @match: Callback function to check device
4089 * @data: Data to pass to match function
4090 *
4091 * This is similar to the device_for_each_child() function above, but it
4092 * returns a reference to a device that is 'found' for later use, as
4093 * determined by the @match callback.
4094 *
4095 * The callback should return 0 if the device doesn't match and non-zero
4096 * if it does. If the callback returns non-zero and a reference to the
4097 * current device can be obtained, this function will return to the caller
4098 * and not iterate over any more devices.
4099 *
4100 * NOTE: you will need to drop the reference with put_device() after use.
4101 */
4102struct device *device_find_child(struct device *parent, void *data,
4103 int (*match)(struct device *dev, void *data))
4104{
4105 struct klist_iter i;
4106 struct device *child;
4107
4108 if (!parent)
4109 return NULL;
4110
4111 klist_iter_init(&parent->p->klist_children, &i);
4112 while ((child = next_device(&i)))
4113 if (match(child, data) && get_device(child))
4114 break;
4115 klist_iter_exit(&i);
4116 return child;
4117}
4118EXPORT_SYMBOL_GPL(device_find_child);
4119
4120/**
4121 * device_find_child_by_name - device iterator for locating a child device.
4122 * @parent: parent struct device
4123 * @name: name of the child device
4124 *
4125 * This is similar to the device_find_child() function above, but it
4126 * returns a reference to a device that has the name @name.
4127 *
4128 * NOTE: you will need to drop the reference with put_device() after use.
4129 */
4130struct device *device_find_child_by_name(struct device *parent,
4131 const char *name)
4132{
4133 struct klist_iter i;
4134 struct device *child;
4135
4136 if (!parent)
4137 return NULL;
4138
4139 klist_iter_init(&parent->p->klist_children, &i);
4140 while ((child = next_device(&i)))
4141 if (sysfs_streq(dev_name(child), name) && get_device(child))
4142 break;
4143 klist_iter_exit(&i);
4144 return child;
4145}
4146EXPORT_SYMBOL_GPL(device_find_child_by_name);
4147
4148static int match_any(struct device *dev, void *unused)
4149{
4150 return 1;
4151}
4152
4153/**
4154 * device_find_any_child - device iterator for locating a child device, if any.
4155 * @parent: parent struct device
4156 *
4157 * This is similar to the device_find_child() function above, but it
4158 * returns a reference to a child device, if any.
4159 *
4160 * NOTE: you will need to drop the reference with put_device() after use.
4161 */
4162struct device *device_find_any_child(struct device *parent)
4163{
4164 return device_find_child(parent, NULL, match_any);
4165}
4166EXPORT_SYMBOL_GPL(device_find_any_child);
4167
4168int __init devices_init(void)
4169{
4170 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
4171 if (!devices_kset)
4172 return -ENOMEM;
4173 dev_kobj = kobject_create_and_add("dev", NULL);
4174 if (!dev_kobj)
4175 goto dev_kobj_err;
4176 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
4177 if (!sysfs_dev_block_kobj)
4178 goto block_kobj_err;
4179 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
4180 if (!sysfs_dev_char_kobj)
4181 goto char_kobj_err;
4182 device_link_wq = alloc_workqueue("device_link_wq", 0, 0);
4183 if (!device_link_wq)
4184 goto wq_err;
4185
4186 return 0;
4187
4188 wq_err:
4189 kobject_put(sysfs_dev_char_kobj);
4190 char_kobj_err:
4191 kobject_put(sysfs_dev_block_kobj);
4192 block_kobj_err:
4193 kobject_put(dev_kobj);
4194 dev_kobj_err:
4195 kset_unregister(devices_kset);
4196 return -ENOMEM;
4197}
4198
4199static int device_check_offline(struct device *dev, void *not_used)
4200{
4201 int ret;
4202
4203 ret = device_for_each_child(dev, NULL, device_check_offline);
4204 if (ret)
4205 return ret;
4206
4207 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
4208}
4209
4210/**
4211 * device_offline - Prepare the device for hot-removal.
4212 * @dev: Device to be put offline.
4213 *
4214 * Execute the device bus type's .offline() callback, if present, to prepare
4215 * the device for a subsequent hot-removal. If that succeeds, the device must
4216 * not be used until either it is removed or its bus type's .online() callback
4217 * is executed.
4218 *
4219 * Call under device_hotplug_lock.
4220 */
4221int device_offline(struct device *dev)
4222{
4223 int ret;
4224
4225 if (dev->offline_disabled)
4226 return -EPERM;
4227
4228 ret = device_for_each_child(dev, NULL, device_check_offline);
4229 if (ret)
4230 return ret;
4231
4232 device_lock(dev);
4233 if (device_supports_offline(dev)) {
4234 if (dev->offline) {
4235 ret = 1;
4236 } else {
4237 ret = dev->bus->offline(dev);
4238 if (!ret) {
4239 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
4240 dev->offline = true;
4241 }
4242 }
4243 }
4244 device_unlock(dev);
4245
4246 return ret;
4247}
4248
4249/**
4250 * device_online - Put the device back online after successful device_offline().
4251 * @dev: Device to be put back online.
4252 *
4253 * If device_offline() has been successfully executed for @dev, but the device
4254 * has not been removed subsequently, execute its bus type's .online() callback
4255 * to indicate that the device can be used again.
4256 *
4257 * Call under device_hotplug_lock.
4258 */
4259int device_online(struct device *dev)
4260{
4261 int ret = 0;
4262
4263 device_lock(dev);
4264 if (device_supports_offline(dev)) {
4265 if (dev->offline) {
4266 ret = dev->bus->online(dev);
4267 if (!ret) {
4268 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
4269 dev->offline = false;
4270 }
4271 } else {
4272 ret = 1;
4273 }
4274 }
4275 device_unlock(dev);
4276
4277 return ret;
4278}
4279
4280struct root_device {
4281 struct device dev;
4282 struct module *owner;
4283};
4284
4285static inline struct root_device *to_root_device(struct device *d)
4286{
4287 return container_of(d, struct root_device, dev);
4288}
4289
4290static void root_device_release(struct device *dev)
4291{
4292 kfree(to_root_device(dev));
4293}
4294
4295/**
4296 * __root_device_register - allocate and register a root device
4297 * @name: root device name
4298 * @owner: owner module of the root device, usually THIS_MODULE
4299 *
4300 * This function allocates a root device and registers it
4301 * using device_register(). In order to free the returned
4302 * device, use root_device_unregister().
4303 *
4304 * Root devices are dummy devices which allow other devices
4305 * to be grouped under /sys/devices. Use this function to
4306 * allocate a root device and then use it as the parent of
4307 * any device which should appear under /sys/devices/{name}
4308 *
4309 * The /sys/devices/{name} directory will also contain a
4310 * 'module' symlink which points to the @owner directory
4311 * in sysfs.
4312 *
4313 * Returns &struct device pointer on success, or ERR_PTR() on error.
4314 *
4315 * Note: You probably want to use root_device_register().
4316 */
4317struct device *__root_device_register(const char *name, struct module *owner)
4318{
4319 struct root_device *root;
4320 int err = -ENOMEM;
4321
4322 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
4323 if (!root)
4324 return ERR_PTR(err);
4325
4326 err = dev_set_name(&root->dev, "%s", name);
4327 if (err) {
4328 kfree(root);
4329 return ERR_PTR(err);
4330 }
4331
4332 root->dev.release = root_device_release;
4333
4334 err = device_register(&root->dev);
4335 if (err) {
4336 put_device(&root->dev);
4337 return ERR_PTR(err);
4338 }
4339
4340#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
4341 if (owner) {
4342 struct module_kobject *mk = &owner->mkobj;
4343
4344 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
4345 if (err) {
4346 device_unregister(&root->dev);
4347 return ERR_PTR(err);
4348 }
4349 root->owner = owner;
4350 }
4351#endif
4352
4353 return &root->dev;
4354}
4355EXPORT_SYMBOL_GPL(__root_device_register);
4356
4357/**
4358 * root_device_unregister - unregister and free a root device
4359 * @dev: device going away
4360 *
4361 * This function unregisters and cleans up a device that was created by
4362 * root_device_register().
4363 */
4364void root_device_unregister(struct device *dev)
4365{
4366 struct root_device *root = to_root_device(dev);
4367
4368 if (root->owner)
4369 sysfs_remove_link(&root->dev.kobj, "module");
4370
4371 device_unregister(dev);
4372}
4373EXPORT_SYMBOL_GPL(root_device_unregister);
4374
4375
4376static void device_create_release(struct device *dev)
4377{
4378 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4379 kfree(dev);
4380}
4381
4382static __printf(6, 0) struct device *
4383device_create_groups_vargs(const struct class *class, struct device *parent,
4384 dev_t devt, void *drvdata,
4385 const struct attribute_group **groups,
4386 const char *fmt, va_list args)
4387{
4388 struct device *dev = NULL;
4389 int retval = -ENODEV;
4390
4391 if (IS_ERR_OR_NULL(class))
4392 goto error;
4393
4394 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4395 if (!dev) {
4396 retval = -ENOMEM;
4397 goto error;
4398 }
4399
4400 device_initialize(dev);
4401 dev->devt = devt;
4402 dev->class = class;
4403 dev->parent = parent;
4404 dev->groups = groups;
4405 dev->release = device_create_release;
4406 dev_set_drvdata(dev, drvdata);
4407
4408 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4409 if (retval)
4410 goto error;
4411
4412 retval = device_add(dev);
4413 if (retval)
4414 goto error;
4415
4416 return dev;
4417
4418error:
4419 put_device(dev);
4420 return ERR_PTR(retval);
4421}
4422
4423/**
4424 * device_create - creates a device and registers it with sysfs
4425 * @class: pointer to the struct class that this device should be registered to
4426 * @parent: pointer to the parent struct device of this new device, if any
4427 * @devt: the dev_t for the char device to be added
4428 * @drvdata: the data to be added to the device for callbacks
4429 * @fmt: string for the device's name
4430 *
4431 * This function can be used by char device classes. A struct device
4432 * will be created in sysfs, registered to the specified class.
4433 *
4434 * A "dev" file will be created, showing the dev_t for the device, if
4435 * the dev_t is not 0,0.
4436 * If a pointer to a parent struct device is passed in, the newly created
4437 * struct device will be a child of that device in sysfs.
4438 * The pointer to the struct device will be returned from the call.
4439 * Any further sysfs files that might be required can be created using this
4440 * pointer.
4441 *
4442 * Returns &struct device pointer on success, or ERR_PTR() on error.
4443 */
4444struct device *device_create(const struct class *class, struct device *parent,
4445 dev_t devt, void *drvdata, const char *fmt, ...)
4446{
4447 va_list vargs;
4448 struct device *dev;
4449
4450 va_start(vargs, fmt);
4451 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4452 fmt, vargs);
4453 va_end(vargs);
4454 return dev;
4455}
4456EXPORT_SYMBOL_GPL(device_create);
4457
4458/**
4459 * device_create_with_groups - creates a device and registers it with sysfs
4460 * @class: pointer to the struct class that this device should be registered to
4461 * @parent: pointer to the parent struct device of this new device, if any
4462 * @devt: the dev_t for the char device to be added
4463 * @drvdata: the data to be added to the device for callbacks
4464 * @groups: NULL-terminated list of attribute groups to be created
4465 * @fmt: string for the device's name
4466 *
4467 * This function can be used by char device classes. A struct device
4468 * will be created in sysfs, registered to the specified class.
4469 * Additional attributes specified in the groups parameter will also
4470 * be created automatically.
4471 *
4472 * A "dev" file will be created, showing the dev_t for the device, if
4473 * the dev_t is not 0,0.
4474 * If a pointer to a parent struct device is passed in, the newly created
4475 * struct device will be a child of that device in sysfs.
4476 * The pointer to the struct device will be returned from the call.
4477 * Any further sysfs files that might be required can be created using this
4478 * pointer.
4479 *
4480 * Returns &struct device pointer on success, or ERR_PTR() on error.
4481 */
4482struct device *device_create_with_groups(const struct class *class,
4483 struct device *parent, dev_t devt,
4484 void *drvdata,
4485 const struct attribute_group **groups,
4486 const char *fmt, ...)
4487{
4488 va_list vargs;
4489 struct device *dev;
4490
4491 va_start(vargs, fmt);
4492 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4493 fmt, vargs);
4494 va_end(vargs);
4495 return dev;
4496}
4497EXPORT_SYMBOL_GPL(device_create_with_groups);
4498
4499/**
4500 * device_destroy - removes a device that was created with device_create()
4501 * @class: pointer to the struct class that this device was registered with
4502 * @devt: the dev_t of the device that was previously registered
4503 *
4504 * This call unregisters and cleans up a device that was created with a
4505 * call to device_create().
4506 */
4507void device_destroy(const struct class *class, dev_t devt)
4508{
4509 struct device *dev;
4510
4511 dev = class_find_device_by_devt(class, devt);
4512 if (dev) {
4513 put_device(dev);
4514 device_unregister(dev);
4515 }
4516}
4517EXPORT_SYMBOL_GPL(device_destroy);
4518
4519/**
4520 * device_rename - renames a device
4521 * @dev: the pointer to the struct device to be renamed
4522 * @new_name: the new name of the device
4523 *
4524 * It is the responsibility of the caller to provide mutual
4525 * exclusion between two different calls of device_rename
4526 * on the same device to ensure that new_name is valid and
4527 * won't conflict with other devices.
4528 *
4529 * Note: given that some subsystems (networking and infiniband) use this
4530 * function, with no immediate plans for this to change, we cannot assume or
4531 * require that this function not be called at all.
4532 *
4533 * However, if you're writing new code, do not call this function. The following
4534 * text from Kay Sievers offers some insight:
4535 *
4536 * Renaming devices is racy at many levels, symlinks and other stuff are not
4537 * replaced atomically, and you get a "move" uevent, but it's not easy to
4538 * connect the event to the old and new device. Device nodes are not renamed at
4539 * all, there isn't even support for that in the kernel now.
4540 *
4541 * In the meantime, during renaming, your target name might be taken by another
4542 * driver, creating conflicts. Or the old name is taken directly after you
4543 * renamed it -- then you get events for the same DEVPATH, before you even see
4544 * the "move" event. It's just a mess, and nothing new should ever rely on
4545 * kernel device renaming. Besides that, it's not even implemented now for
4546 * other things than (driver-core wise very simple) network devices.
4547 *
4548 * Make up a "real" name in the driver before you register anything, or add
4549 * some other attributes for userspace to find the device, or use udev to add
4550 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4551 * don't even want to get into that and try to implement the missing pieces in
4552 * the core. We really have other pieces to fix in the driver core mess. :)
4553 */
4554int device_rename(struct device *dev, const char *new_name)
4555{
4556 struct kobject *kobj = &dev->kobj;
4557 char *old_device_name = NULL;
4558 int error;
4559
4560 dev = get_device(dev);
4561 if (!dev)
4562 return -EINVAL;
4563
4564 dev_dbg(dev, "renaming to %s\n", new_name);
4565
4566 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4567 if (!old_device_name) {
4568 error = -ENOMEM;
4569 goto out;
4570 }
4571
4572 if (dev->class) {
4573 struct subsys_private *sp = class_to_subsys(dev->class);
4574
4575 if (!sp) {
4576 error = -EINVAL;
4577 goto out;
4578 }
4579
4580 error = sysfs_rename_link_ns(&sp->subsys.kobj, kobj, old_device_name,
4581 new_name, kobject_namespace(kobj));
4582 subsys_put(sp);
4583 if (error)
4584 goto out;
4585 }
4586
4587 error = kobject_rename(kobj, new_name);
4588 if (error)
4589 goto out;
4590
4591out:
4592 put_device(dev);
4593
4594 kfree(old_device_name);
4595
4596 return error;
4597}
4598EXPORT_SYMBOL_GPL(device_rename);
4599
4600static int device_move_class_links(struct device *dev,
4601 struct device *old_parent,
4602 struct device *new_parent)
4603{
4604 int error = 0;
4605
4606 if (old_parent)
4607 sysfs_remove_link(&dev->kobj, "device");
4608 if (new_parent)
4609 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4610 "device");
4611 return error;
4612}
4613
4614/**
4615 * device_move - moves a device to a new parent
4616 * @dev: the pointer to the struct device to be moved
4617 * @new_parent: the new parent of the device (can be NULL)
4618 * @dpm_order: how to reorder the dpm_list
4619 */
4620int device_move(struct device *dev, struct device *new_parent,
4621 enum dpm_order dpm_order)
4622{
4623 int error;
4624 struct device *old_parent;
4625 struct kobject *new_parent_kobj;
4626
4627 dev = get_device(dev);
4628 if (!dev)
4629 return -EINVAL;
4630
4631 device_pm_lock();
4632 new_parent = get_device(new_parent);
4633 new_parent_kobj = get_device_parent(dev, new_parent);
4634 if (IS_ERR(new_parent_kobj)) {
4635 error = PTR_ERR(new_parent_kobj);
4636 put_device(new_parent);
4637 goto out;
4638 }
4639
4640 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4641 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4642 error = kobject_move(&dev->kobj, new_parent_kobj);
4643 if (error) {
4644 cleanup_glue_dir(dev, new_parent_kobj);
4645 put_device(new_parent);
4646 goto out;
4647 }
4648 old_parent = dev->parent;
4649 dev->parent = new_parent;
4650 if (old_parent)
4651 klist_remove(&dev->p->knode_parent);
4652 if (new_parent) {
4653 klist_add_tail(&dev->p->knode_parent,
4654 &new_parent->p->klist_children);
4655 set_dev_node(dev, dev_to_node(new_parent));
4656 }
4657
4658 if (dev->class) {
4659 error = device_move_class_links(dev, old_parent, new_parent);
4660 if (error) {
4661 /* We ignore errors on cleanup since we're hosed anyway... */
4662 device_move_class_links(dev, new_parent, old_parent);
4663 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4664 if (new_parent)
4665 klist_remove(&dev->p->knode_parent);
4666 dev->parent = old_parent;
4667 if (old_parent) {
4668 klist_add_tail(&dev->p->knode_parent,
4669 &old_parent->p->klist_children);
4670 set_dev_node(dev, dev_to_node(old_parent));
4671 }
4672 }
4673 cleanup_glue_dir(dev, new_parent_kobj);
4674 put_device(new_parent);
4675 goto out;
4676 }
4677 }
4678 switch (dpm_order) {
4679 case DPM_ORDER_NONE:
4680 break;
4681 case DPM_ORDER_DEV_AFTER_PARENT:
4682 device_pm_move_after(dev, new_parent);
4683 devices_kset_move_after(dev, new_parent);
4684 break;
4685 case DPM_ORDER_PARENT_BEFORE_DEV:
4686 device_pm_move_before(new_parent, dev);
4687 devices_kset_move_before(new_parent, dev);
4688 break;
4689 case DPM_ORDER_DEV_LAST:
4690 device_pm_move_last(dev);
4691 devices_kset_move_last(dev);
4692 break;
4693 }
4694
4695 put_device(old_parent);
4696out:
4697 device_pm_unlock();
4698 put_device(dev);
4699 return error;
4700}
4701EXPORT_SYMBOL_GPL(device_move);
4702
4703static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4704 kgid_t kgid)
4705{
4706 struct kobject *kobj = &dev->kobj;
4707 const struct class *class = dev->class;
4708 const struct device_type *type = dev->type;
4709 int error;
4710
4711 if (class) {
4712 /*
4713 * Change the device groups of the device class for @dev to
4714 * @kuid/@kgid.
4715 */
4716 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4717 kgid);
4718 if (error)
4719 return error;
4720 }
4721
4722 if (type) {
4723 /*
4724 * Change the device groups of the device type for @dev to
4725 * @kuid/@kgid.
4726 */
4727 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4728 kgid);
4729 if (error)
4730 return error;
4731 }
4732
4733 /* Change the device groups of @dev to @kuid/@kgid. */
4734 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4735 if (error)
4736 return error;
4737
4738 if (device_supports_offline(dev) && !dev->offline_disabled) {
4739 /* Change online device attributes of @dev to @kuid/@kgid. */
4740 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4741 kuid, kgid);
4742 if (error)
4743 return error;
4744 }
4745
4746 return 0;
4747}
4748
4749/**
4750 * device_change_owner - change the owner of an existing device.
4751 * @dev: device.
4752 * @kuid: new owner's kuid
4753 * @kgid: new owner's kgid
4754 *
4755 * This changes the owner of @dev and its corresponding sysfs entries to
4756 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4757 * core.
4758 *
4759 * Returns 0 on success or error code on failure.
4760 */
4761int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4762{
4763 int error;
4764 struct kobject *kobj = &dev->kobj;
4765 struct subsys_private *sp;
4766
4767 dev = get_device(dev);
4768 if (!dev)
4769 return -EINVAL;
4770
4771 /*
4772 * Change the kobject and the default attributes and groups of the
4773 * ktype associated with it to @kuid/@kgid.
4774 */
4775 error = sysfs_change_owner(kobj, kuid, kgid);
4776 if (error)
4777 goto out;
4778
4779 /*
4780 * Change the uevent file for @dev to the new owner. The uevent file
4781 * was created in a separate step when @dev got added and we mirror
4782 * that step here.
4783 */
4784 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4785 kgid);
4786 if (error)
4787 goto out;
4788
4789 /*
4790 * Change the device groups, the device groups associated with the
4791 * device class, and the groups associated with the device type of @dev
4792 * to @kuid/@kgid.
4793 */
4794 error = device_attrs_change_owner(dev, kuid, kgid);
4795 if (error)
4796 goto out;
4797
4798 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4799 if (error)
4800 goto out;
4801
4802 /*
4803 * Change the owner of the symlink located in the class directory of
4804 * the device class associated with @dev which points to the actual
4805 * directory entry for @dev to @kuid/@kgid. This ensures that the
4806 * symlink shows the same permissions as its target.
4807 */
4808 sp = class_to_subsys(dev->class);
4809 if (!sp) {
4810 error = -EINVAL;
4811 goto out;
4812 }
4813 error = sysfs_link_change_owner(&sp->subsys.kobj, &dev->kobj, dev_name(dev), kuid, kgid);
4814 subsys_put(sp);
4815
4816out:
4817 put_device(dev);
4818 return error;
4819}
4820EXPORT_SYMBOL_GPL(device_change_owner);
4821
4822/**
4823 * device_shutdown - call ->shutdown() on each device to shutdown.
4824 */
4825void device_shutdown(void)
4826{
4827 struct device *dev, *parent;
4828
4829 wait_for_device_probe();
4830 device_block_probing();
4831
4832 cpufreq_suspend();
4833
4834 spin_lock(&devices_kset->list_lock);
4835 /*
4836 * Walk the devices list backward, shutting down each in turn.
4837 * Beware that device unplug events may also start pulling
4838 * devices offline, even as the system is shutting down.
4839 */
4840 while (!list_empty(&devices_kset->list)) {
4841 dev = list_entry(devices_kset->list.prev, struct device,
4842 kobj.entry);
4843
4844 /*
4845 * hold reference count of device's parent to
4846 * prevent it from being freed because parent's
4847 * lock is to be held
4848 */
4849 parent = get_device(dev->parent);
4850 get_device(dev);
4851 /*
4852 * Make sure the device is off the kset list, in the
4853 * event that dev->*->shutdown() doesn't remove it.
4854 */
4855 list_del_init(&dev->kobj.entry);
4856 spin_unlock(&devices_kset->list_lock);
4857
4858 /* hold lock to avoid race with probe/release */
4859 if (parent)
4860 device_lock(parent);
4861 device_lock(dev);
4862
4863 /* Don't allow any more runtime suspends */
4864 pm_runtime_get_noresume(dev);
4865 pm_runtime_barrier(dev);
4866
4867 if (dev->class && dev->class->shutdown_pre) {
4868 if (initcall_debug)
4869 dev_info(dev, "shutdown_pre\n");
4870 dev->class->shutdown_pre(dev);
4871 }
4872 if (dev->bus && dev->bus->shutdown) {
4873 if (initcall_debug)
4874 dev_info(dev, "shutdown\n");
4875 dev->bus->shutdown(dev);
4876 } else if (dev->driver && dev->driver->shutdown) {
4877 if (initcall_debug)
4878 dev_info(dev, "shutdown\n");
4879 dev->driver->shutdown(dev);
4880 }
4881
4882 device_unlock(dev);
4883 if (parent)
4884 device_unlock(parent);
4885
4886 put_device(dev);
4887 put_device(parent);
4888
4889 spin_lock(&devices_kset->list_lock);
4890 }
4891 spin_unlock(&devices_kset->list_lock);
4892}
4893
4894/*
4895 * Device logging functions
4896 */
4897
4898#ifdef CONFIG_PRINTK
4899static void
4900set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4901{
4902 const char *subsys;
4903
4904 memset(dev_info, 0, sizeof(*dev_info));
4905
4906 if (dev->class)
4907 subsys = dev->class->name;
4908 else if (dev->bus)
4909 subsys = dev->bus->name;
4910 else
4911 return;
4912
4913 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4914
4915 /*
4916 * Add device identifier DEVICE=:
4917 * b12:8 block dev_t
4918 * c127:3 char dev_t
4919 * n8 netdev ifindex
4920 * +sound:card0 subsystem:devname
4921 */
4922 if (MAJOR(dev->devt)) {
4923 char c;
4924
4925 if (strcmp(subsys, "block") == 0)
4926 c = 'b';
4927 else
4928 c = 'c';
4929
4930 snprintf(dev_info->device, sizeof(dev_info->device),
4931 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4932 } else if (strcmp(subsys, "net") == 0) {
4933 struct net_device *net = to_net_dev(dev);
4934
4935 snprintf(dev_info->device, sizeof(dev_info->device),
4936 "n%u", net->ifindex);
4937 } else {
4938 snprintf(dev_info->device, sizeof(dev_info->device),
4939 "+%s:%s", subsys, dev_name(dev));
4940 }
4941}
4942
4943int dev_vprintk_emit(int level, const struct device *dev,
4944 const char *fmt, va_list args)
4945{
4946 struct dev_printk_info dev_info;
4947
4948 set_dev_info(dev, &dev_info);
4949
4950 return vprintk_emit(0, level, &dev_info, fmt, args);
4951}
4952EXPORT_SYMBOL(dev_vprintk_emit);
4953
4954int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4955{
4956 va_list args;
4957 int r;
4958
4959 va_start(args, fmt);
4960
4961 r = dev_vprintk_emit(level, dev, fmt, args);
4962
4963 va_end(args);
4964
4965 return r;
4966}
4967EXPORT_SYMBOL(dev_printk_emit);
4968
4969static void __dev_printk(const char *level, const struct device *dev,
4970 struct va_format *vaf)
4971{
4972 if (dev)
4973 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4974 dev_driver_string(dev), dev_name(dev), vaf);
4975 else
4976 printk("%s(NULL device *): %pV", level, vaf);
4977}
4978
4979void _dev_printk(const char *level, const struct device *dev,
4980 const char *fmt, ...)
4981{
4982 struct va_format vaf;
4983 va_list args;
4984
4985 va_start(args, fmt);
4986
4987 vaf.fmt = fmt;
4988 vaf.va = &args;
4989
4990 __dev_printk(level, dev, &vaf);
4991
4992 va_end(args);
4993}
4994EXPORT_SYMBOL(_dev_printk);
4995
4996#define define_dev_printk_level(func, kern_level) \
4997void func(const struct device *dev, const char *fmt, ...) \
4998{ \
4999 struct va_format vaf; \
5000 va_list args; \
5001 \
5002 va_start(args, fmt); \
5003 \
5004 vaf.fmt = fmt; \
5005 vaf.va = &args; \
5006 \
5007 __dev_printk(kern_level, dev, &vaf); \
5008 \
5009 va_end(args); \
5010} \
5011EXPORT_SYMBOL(func);
5012
5013define_dev_printk_level(_dev_emerg, KERN_EMERG);
5014define_dev_printk_level(_dev_alert, KERN_ALERT);
5015define_dev_printk_level(_dev_crit, KERN_CRIT);
5016define_dev_printk_level(_dev_err, KERN_ERR);
5017define_dev_printk_level(_dev_warn, KERN_WARNING);
5018define_dev_printk_level(_dev_notice, KERN_NOTICE);
5019define_dev_printk_level(_dev_info, KERN_INFO);
5020
5021#endif
5022
5023/**
5024 * dev_err_probe - probe error check and log helper
5025 * @dev: the pointer to the struct device
5026 * @err: error value to test
5027 * @fmt: printf-style format string
5028 * @...: arguments as specified in the format string
5029 *
5030 * This helper implements common pattern present in probe functions for error
5031 * checking: print debug or error message depending if the error value is
5032 * -EPROBE_DEFER and propagate error upwards.
5033 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
5034 * checked later by reading devices_deferred debugfs attribute.
5035 * It replaces code sequence::
5036 *
5037 * if (err != -EPROBE_DEFER)
5038 * dev_err(dev, ...);
5039 * else
5040 * dev_dbg(dev, ...);
5041 * return err;
5042 *
5043 * with::
5044 *
5045 * return dev_err_probe(dev, err, ...);
5046 *
5047 * Using this helper in your probe function is totally fine even if @err is
5048 * known to never be -EPROBE_DEFER.
5049 * The benefit compared to a normal dev_err() is the standardized format
5050 * of the error code, it being emitted symbolically (i.e. you get "EAGAIN"
5051 * instead of "-35") and the fact that the error code is returned which allows
5052 * more compact error paths.
5053 *
5054 * Returns @err.
5055 */
5056int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
5057{
5058 struct va_format vaf;
5059 va_list args;
5060
5061 va_start(args, fmt);
5062 vaf.fmt = fmt;
5063 vaf.va = &args;
5064
5065 if (err != -EPROBE_DEFER) {
5066 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
5067 } else {
5068 device_set_deferred_probe_reason(dev, &vaf);
5069 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
5070 }
5071
5072 va_end(args);
5073
5074 return err;
5075}
5076EXPORT_SYMBOL_GPL(dev_err_probe);
5077
5078static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
5079{
5080 return fwnode && !IS_ERR(fwnode->secondary);
5081}
5082
5083/**
5084 * set_primary_fwnode - Change the primary firmware node of a given device.
5085 * @dev: Device to handle.
5086 * @fwnode: New primary firmware node of the device.
5087 *
5088 * Set the device's firmware node pointer to @fwnode, but if a secondary
5089 * firmware node of the device is present, preserve it.
5090 *
5091 * Valid fwnode cases are:
5092 * - primary --> secondary --> -ENODEV
5093 * - primary --> NULL
5094 * - secondary --> -ENODEV
5095 * - NULL
5096 */
5097void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5098{
5099 struct device *parent = dev->parent;
5100 struct fwnode_handle *fn = dev->fwnode;
5101
5102 if (fwnode) {
5103 if (fwnode_is_primary(fn))
5104 fn = fn->secondary;
5105
5106 if (fn) {
5107 WARN_ON(fwnode->secondary);
5108 fwnode->secondary = fn;
5109 }
5110 dev->fwnode = fwnode;
5111 } else {
5112 if (fwnode_is_primary(fn)) {
5113 dev->fwnode = fn->secondary;
5114
5115 /* Skip nullifying fn->secondary if the primary is shared */
5116 if (parent && fn == parent->fwnode)
5117 return;
5118
5119 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
5120 fn->secondary = NULL;
5121 } else {
5122 dev->fwnode = NULL;
5123 }
5124 }
5125}
5126EXPORT_SYMBOL_GPL(set_primary_fwnode);
5127
5128/**
5129 * set_secondary_fwnode - Change the secondary firmware node of a given device.
5130 * @dev: Device to handle.
5131 * @fwnode: New secondary firmware node of the device.
5132 *
5133 * If a primary firmware node of the device is present, set its secondary
5134 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
5135 * @fwnode.
5136 */
5137void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5138{
5139 if (fwnode)
5140 fwnode->secondary = ERR_PTR(-ENODEV);
5141
5142 if (fwnode_is_primary(dev->fwnode))
5143 dev->fwnode->secondary = fwnode;
5144 else
5145 dev->fwnode = fwnode;
5146}
5147EXPORT_SYMBOL_GPL(set_secondary_fwnode);
5148
5149/**
5150 * device_set_of_node_from_dev - reuse device-tree node of another device
5151 * @dev: device whose device-tree node is being set
5152 * @dev2: device whose device-tree node is being reused
5153 *
5154 * Takes another reference to the new device-tree node after first dropping
5155 * any reference held to the old node.
5156 */
5157void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
5158{
5159 of_node_put(dev->of_node);
5160 dev->of_node = of_node_get(dev2->of_node);
5161 dev->of_node_reused = true;
5162}
5163EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
5164
5165void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
5166{
5167 dev->fwnode = fwnode;
5168 dev->of_node = to_of_node(fwnode);
5169}
5170EXPORT_SYMBOL_GPL(device_set_node);
5171
5172int device_match_name(struct device *dev, const void *name)
5173{
5174 return sysfs_streq(dev_name(dev), name);
5175}
5176EXPORT_SYMBOL_GPL(device_match_name);
5177
5178int device_match_of_node(struct device *dev, const void *np)
5179{
5180 return dev->of_node == np;
5181}
5182EXPORT_SYMBOL_GPL(device_match_of_node);
5183
5184int device_match_fwnode(struct device *dev, const void *fwnode)
5185{
5186 return dev_fwnode(dev) == fwnode;
5187}
5188EXPORT_SYMBOL_GPL(device_match_fwnode);
5189
5190int device_match_devt(struct device *dev, const void *pdevt)
5191{
5192 return dev->devt == *(dev_t *)pdevt;
5193}
5194EXPORT_SYMBOL_GPL(device_match_devt);
5195
5196int device_match_acpi_dev(struct device *dev, const void *adev)
5197{
5198 return ACPI_COMPANION(dev) == adev;
5199}
5200EXPORT_SYMBOL(device_match_acpi_dev);
5201
5202int device_match_acpi_handle(struct device *dev, const void *handle)
5203{
5204 return ACPI_HANDLE(dev) == handle;
5205}
5206EXPORT_SYMBOL(device_match_acpi_handle);
5207
5208int device_match_any(struct device *dev, const void *unused)
5209{
5210 return 1;
5211}
5212EXPORT_SYMBOL_GPL(device_match_any);