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