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[mirror_ubuntu-zesty-kernel.git] / drivers / base / core.c
1 /*
2 * drivers/base/core.c - core driver model code (device registration, etc)
3 *
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (c) 2006 Novell, Inc.
8 *
9 * This file is released under the GPLv2
10 *
11 */
12
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/fwnode.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/string.h>
20 #include <linux/kdev_t.h>
21 #include <linux/notifier.h>
22 #include <linux/of.h>
23 #include <linux/of_device.h>
24 #include <linux/genhd.h>
25 #include <linux/kallsyms.h>
26 #include <linux/mutex.h>
27 #include <linux/pm_runtime.h>
28 #include <linux/netdevice.h>
29 #include <linux/sysfs.h>
30
31 #include "base.h"
32 #include "power/power.h"
33
34 #ifdef CONFIG_SYSFS_DEPRECATED
35 #ifdef CONFIG_SYSFS_DEPRECATED_V2
36 long sysfs_deprecated = 1;
37 #else
38 long sysfs_deprecated = 0;
39 #endif
40 static int __init sysfs_deprecated_setup(char *arg)
41 {
42 return kstrtol(arg, 10, &sysfs_deprecated);
43 }
44 early_param("sysfs.deprecated", sysfs_deprecated_setup);
45 #endif
46
47 /* Device links support. */
48
49 #ifdef CONFIG_SRCU
50 static DEFINE_MUTEX(device_links_lock);
51 DEFINE_STATIC_SRCU(device_links_srcu);
52
53 static inline void device_links_write_lock(void)
54 {
55 mutex_lock(&device_links_lock);
56 }
57
58 static inline void device_links_write_unlock(void)
59 {
60 mutex_unlock(&device_links_lock);
61 }
62
63 int device_links_read_lock(void)
64 {
65 return srcu_read_lock(&device_links_srcu);
66 }
67
68 void device_links_read_unlock(int idx)
69 {
70 srcu_read_unlock(&device_links_srcu, idx);
71 }
72 #else /* !CONFIG_SRCU */
73 static DECLARE_RWSEM(device_links_lock);
74
75 static inline void device_links_write_lock(void)
76 {
77 down_write(&device_links_lock);
78 }
79
80 static inline void device_links_write_unlock(void)
81 {
82 up_write(&device_links_lock);
83 }
84
85 int device_links_read_lock(void)
86 {
87 down_read(&device_links_lock);
88 return 0;
89 }
90
91 void device_links_read_unlock(int not_used)
92 {
93 up_read(&device_links_lock);
94 }
95 #endif /* !CONFIG_SRCU */
96
97 /**
98 * device_is_dependent - Check if one device depends on another one
99 * @dev: Device to check dependencies for.
100 * @target: Device to check against.
101 *
102 * Check if @target depends on @dev or any device dependent on it (its child or
103 * its consumer etc). Return 1 if that is the case or 0 otherwise.
104 */
105 static int device_is_dependent(struct device *dev, void *target)
106 {
107 struct device_link *link;
108 int ret;
109
110 if (WARN_ON(dev == target))
111 return 1;
112
113 ret = device_for_each_child(dev, target, device_is_dependent);
114 if (ret)
115 return ret;
116
117 list_for_each_entry(link, &dev->links.consumers, s_node) {
118 if (WARN_ON(link->consumer == target))
119 return 1;
120
121 ret = device_is_dependent(link->consumer, target);
122 if (ret)
123 break;
124 }
125 return ret;
126 }
127
128 static int device_reorder_to_tail(struct device *dev, void *not_used)
129 {
130 struct device_link *link;
131
132 /*
133 * Devices that have not been registered yet will be put to the ends
134 * of the lists during the registration, so skip them here.
135 */
136 if (device_is_registered(dev))
137 devices_kset_move_last(dev);
138
139 if (device_pm_initialized(dev))
140 device_pm_move_last(dev);
141
142 device_for_each_child(dev, NULL, device_reorder_to_tail);
143 list_for_each_entry(link, &dev->links.consumers, s_node)
144 device_reorder_to_tail(link->consumer, NULL);
145
146 return 0;
147 }
148
149 /**
150 * device_link_add - Create a link between two devices.
151 * @consumer: Consumer end of the link.
152 * @supplier: Supplier end of the link.
153 * @flags: Link flags.
154 *
155 * The caller is responsible for the proper synchronization of the link creation
156 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
157 * runtime PM framework to take the link into account. Second, if the
158 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
159 * be forced into the active metastate and reference-counted upon the creation
160 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
161 * ignored.
162 *
163 * If the DL_FLAG_AUTOREMOVE is set, the link will be removed automatically
164 * when the consumer device driver unbinds from it. The combination of both
165 * DL_FLAG_AUTOREMOVE and DL_FLAG_STATELESS set is invalid and will cause NULL
166 * to be returned.
167 *
168 * A side effect of the link creation is re-ordering of dpm_list and the
169 * devices_kset list by moving the consumer device and all devices depending
170 * on it to the ends of these lists (that does not happen to devices that have
171 * not been registered when this function is called).
172 *
173 * The supplier device is required to be registered when this function is called
174 * and NULL will be returned if that is not the case. The consumer device need
175 * not be registered, however.
176 */
177 struct device_link *device_link_add(struct device *consumer,
178 struct device *supplier, u32 flags)
179 {
180 struct device_link *link;
181
182 if (!consumer || !supplier ||
183 ((flags & DL_FLAG_STATELESS) && (flags & DL_FLAG_AUTOREMOVE)))
184 return NULL;
185
186 device_links_write_lock();
187 device_pm_lock();
188
189 /*
190 * If the supplier has not been fully registered yet or there is a
191 * reverse dependency between the consumer and the supplier already in
192 * the graph, return NULL.
193 */
194 if (!device_pm_initialized(supplier)
195 || device_is_dependent(consumer, supplier)) {
196 link = NULL;
197 goto out;
198 }
199
200 list_for_each_entry(link, &supplier->links.consumers, s_node)
201 if (link->consumer == consumer)
202 goto out;
203
204 link = kzalloc(sizeof(*link), GFP_KERNEL);
205 if (!link)
206 goto out;
207
208 if (flags & DL_FLAG_PM_RUNTIME) {
209 if (flags & DL_FLAG_RPM_ACTIVE) {
210 if (pm_runtime_get_sync(supplier) < 0) {
211 pm_runtime_put_noidle(supplier);
212 kfree(link);
213 link = NULL;
214 goto out;
215 }
216 link->rpm_active = true;
217 }
218 pm_runtime_new_link(consumer);
219 }
220 get_device(supplier);
221 link->supplier = supplier;
222 INIT_LIST_HEAD(&link->s_node);
223 get_device(consumer);
224 link->consumer = consumer;
225 INIT_LIST_HEAD(&link->c_node);
226 link->flags = flags;
227
228 /* Determine the initial link state. */
229 if (flags & DL_FLAG_STATELESS) {
230 link->status = DL_STATE_NONE;
231 } else {
232 switch (supplier->links.status) {
233 case DL_DEV_DRIVER_BOUND:
234 switch (consumer->links.status) {
235 case DL_DEV_PROBING:
236 /*
237 * Balance the decrementation of the supplier's
238 * runtime PM usage counter after consumer probe
239 * in driver_probe_device().
240 */
241 if (flags & DL_FLAG_PM_RUNTIME)
242 pm_runtime_get_sync(supplier);
243
244 link->status = DL_STATE_CONSUMER_PROBE;
245 break;
246 case DL_DEV_DRIVER_BOUND:
247 link->status = DL_STATE_ACTIVE;
248 break;
249 default:
250 link->status = DL_STATE_AVAILABLE;
251 break;
252 }
253 break;
254 case DL_DEV_UNBINDING:
255 link->status = DL_STATE_SUPPLIER_UNBIND;
256 break;
257 default:
258 link->status = DL_STATE_DORMANT;
259 break;
260 }
261 }
262
263 /*
264 * Move the consumer and all of the devices depending on it to the end
265 * of dpm_list and the devices_kset list.
266 *
267 * It is necessary to hold dpm_list locked throughout all that or else
268 * we may end up suspending with a wrong ordering of it.
269 */
270 device_reorder_to_tail(consumer, NULL);
271
272 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
273 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
274
275 dev_info(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
276
277 out:
278 device_pm_unlock();
279 device_links_write_unlock();
280 return link;
281 }
282 EXPORT_SYMBOL_GPL(device_link_add);
283
284 static void device_link_free(struct device_link *link)
285 {
286 put_device(link->consumer);
287 put_device(link->supplier);
288 kfree(link);
289 }
290
291 #ifdef CONFIG_SRCU
292 static void __device_link_free_srcu(struct rcu_head *rhead)
293 {
294 device_link_free(container_of(rhead, struct device_link, rcu_head));
295 }
296
297 static void __device_link_del(struct device_link *link)
298 {
299 dev_info(link->consumer, "Dropping the link to %s\n",
300 dev_name(link->supplier));
301
302 if (link->flags & DL_FLAG_PM_RUNTIME)
303 pm_runtime_drop_link(link->consumer);
304
305 list_del_rcu(&link->s_node);
306 list_del_rcu(&link->c_node);
307 call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
308 }
309 #else /* !CONFIG_SRCU */
310 static void __device_link_del(struct device_link *link)
311 {
312 dev_info(link->consumer, "Dropping the link to %s\n",
313 dev_name(link->supplier));
314
315 list_del(&link->s_node);
316 list_del(&link->c_node);
317 device_link_free(link);
318 }
319 #endif /* !CONFIG_SRCU */
320
321 /**
322 * device_link_del - Delete a link between two devices.
323 * @link: Device link to delete.
324 *
325 * The caller must ensure proper synchronization of this function with runtime
326 * PM.
327 */
328 void device_link_del(struct device_link *link)
329 {
330 device_links_write_lock();
331 device_pm_lock();
332 __device_link_del(link);
333 device_pm_unlock();
334 device_links_write_unlock();
335 }
336 EXPORT_SYMBOL_GPL(device_link_del);
337
338 static void device_links_missing_supplier(struct device *dev)
339 {
340 struct device_link *link;
341
342 list_for_each_entry(link, &dev->links.suppliers, c_node)
343 if (link->status == DL_STATE_CONSUMER_PROBE)
344 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
345 }
346
347 /**
348 * device_links_check_suppliers - Check presence of supplier drivers.
349 * @dev: Consumer device.
350 *
351 * Check links from this device to any suppliers. Walk the list of the device's
352 * links to suppliers and see if all of them are available. If not, simply
353 * return -EPROBE_DEFER.
354 *
355 * We need to guarantee that the supplier will not go away after the check has
356 * been positive here. It only can go away in __device_release_driver() and
357 * that function checks the device's links to consumers. This means we need to
358 * mark the link as "consumer probe in progress" to make the supplier removal
359 * wait for us to complete (or bad things may happen).
360 *
361 * Links with the DL_FLAG_STATELESS flag set are ignored.
362 */
363 int device_links_check_suppliers(struct device *dev)
364 {
365 struct device_link *link;
366 int ret = 0;
367
368 device_links_write_lock();
369
370 list_for_each_entry(link, &dev->links.suppliers, c_node) {
371 if (link->flags & DL_FLAG_STATELESS)
372 continue;
373
374 if (link->status != DL_STATE_AVAILABLE) {
375 device_links_missing_supplier(dev);
376 ret = -EPROBE_DEFER;
377 break;
378 }
379 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
380 }
381 dev->links.status = DL_DEV_PROBING;
382
383 device_links_write_unlock();
384 return ret;
385 }
386
387 /**
388 * device_links_driver_bound - Update device links after probing its driver.
389 * @dev: Device to update the links for.
390 *
391 * The probe has been successful, so update links from this device to any
392 * consumers by changing their status to "available".
393 *
394 * Also change the status of @dev's links to suppliers to "active".
395 *
396 * Links with the DL_FLAG_STATELESS flag set are ignored.
397 */
398 void device_links_driver_bound(struct device *dev)
399 {
400 struct device_link *link;
401
402 device_links_write_lock();
403
404 list_for_each_entry(link, &dev->links.consumers, s_node) {
405 if (link->flags & DL_FLAG_STATELESS)
406 continue;
407
408 WARN_ON(link->status != DL_STATE_DORMANT);
409 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
410 }
411
412 list_for_each_entry(link, &dev->links.suppliers, c_node) {
413 if (link->flags & DL_FLAG_STATELESS)
414 continue;
415
416 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
417 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
418 }
419
420 dev->links.status = DL_DEV_DRIVER_BOUND;
421
422 device_links_write_unlock();
423 }
424
425 /**
426 * __device_links_no_driver - Update links of a device without a driver.
427 * @dev: Device without a drvier.
428 *
429 * Delete all non-persistent links from this device to any suppliers.
430 *
431 * Persistent links stay around, but their status is changed to "available",
432 * unless they already are in the "supplier unbind in progress" state in which
433 * case they need not be updated.
434 *
435 * Links with the DL_FLAG_STATELESS flag set are ignored.
436 */
437 static void __device_links_no_driver(struct device *dev)
438 {
439 struct device_link *link, *ln;
440
441 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
442 if (link->flags & DL_FLAG_STATELESS)
443 continue;
444
445 if (link->flags & DL_FLAG_AUTOREMOVE)
446 __device_link_del(link);
447 else if (link->status != DL_STATE_SUPPLIER_UNBIND)
448 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
449 }
450
451 dev->links.status = DL_DEV_NO_DRIVER;
452 }
453
454 void device_links_no_driver(struct device *dev)
455 {
456 device_links_write_lock();
457 __device_links_no_driver(dev);
458 device_links_write_unlock();
459 }
460
461 /**
462 * device_links_driver_cleanup - Update links after driver removal.
463 * @dev: Device whose driver has just gone away.
464 *
465 * Update links to consumers for @dev by changing their status to "dormant" and
466 * invoke %__device_links_no_driver() to update links to suppliers for it as
467 * appropriate.
468 *
469 * Links with the DL_FLAG_STATELESS flag set are ignored.
470 */
471 void device_links_driver_cleanup(struct device *dev)
472 {
473 struct device_link *link;
474
475 device_links_write_lock();
476
477 list_for_each_entry(link, &dev->links.consumers, s_node) {
478 if (link->flags & DL_FLAG_STATELESS)
479 continue;
480
481 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE);
482 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
483 WRITE_ONCE(link->status, DL_STATE_DORMANT);
484 }
485
486 __device_links_no_driver(dev);
487
488 device_links_write_unlock();
489 }
490
491 /**
492 * device_links_busy - Check if there are any busy links to consumers.
493 * @dev: Device to check.
494 *
495 * Check each consumer of the device and return 'true' if its link's status
496 * is one of "consumer probe" or "active" (meaning that the given consumer is
497 * probing right now or its driver is present). Otherwise, change the link
498 * state to "supplier unbind" to prevent the consumer from being probed
499 * successfully going forward.
500 *
501 * Return 'false' if there are no probing or active consumers.
502 *
503 * Links with the DL_FLAG_STATELESS flag set are ignored.
504 */
505 bool device_links_busy(struct device *dev)
506 {
507 struct device_link *link;
508 bool ret = false;
509
510 device_links_write_lock();
511
512 list_for_each_entry(link, &dev->links.consumers, s_node) {
513 if (link->flags & DL_FLAG_STATELESS)
514 continue;
515
516 if (link->status == DL_STATE_CONSUMER_PROBE
517 || link->status == DL_STATE_ACTIVE) {
518 ret = true;
519 break;
520 }
521 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
522 }
523
524 dev->links.status = DL_DEV_UNBINDING;
525
526 device_links_write_unlock();
527 return ret;
528 }
529
530 /**
531 * device_links_unbind_consumers - Force unbind consumers of the given device.
532 * @dev: Device to unbind the consumers of.
533 *
534 * Walk the list of links to consumers for @dev and if any of them is in the
535 * "consumer probe" state, wait for all device probes in progress to complete
536 * and start over.
537 *
538 * If that's not the case, change the status of the link to "supplier unbind"
539 * and check if the link was in the "active" state. If so, force the consumer
540 * driver to unbind and start over (the consumer will not re-probe as we have
541 * changed the state of the link already).
542 *
543 * Links with the DL_FLAG_STATELESS flag set are ignored.
544 */
545 void device_links_unbind_consumers(struct device *dev)
546 {
547 struct device_link *link;
548
549 start:
550 device_links_write_lock();
551
552 list_for_each_entry(link, &dev->links.consumers, s_node) {
553 enum device_link_state status;
554
555 if (link->flags & DL_FLAG_STATELESS)
556 continue;
557
558 status = link->status;
559 if (status == DL_STATE_CONSUMER_PROBE) {
560 device_links_write_unlock();
561
562 wait_for_device_probe();
563 goto start;
564 }
565 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
566 if (status == DL_STATE_ACTIVE) {
567 struct device *consumer = link->consumer;
568
569 get_device(consumer);
570
571 device_links_write_unlock();
572
573 device_release_driver_internal(consumer, NULL,
574 consumer->parent);
575 put_device(consumer);
576 goto start;
577 }
578 }
579
580 device_links_write_unlock();
581 }
582
583 /**
584 * device_links_purge - Delete existing links to other devices.
585 * @dev: Target device.
586 */
587 static void device_links_purge(struct device *dev)
588 {
589 struct device_link *link, *ln;
590
591 /*
592 * Delete all of the remaining links from this device to any other
593 * devices (either consumers or suppliers).
594 */
595 device_links_write_lock();
596
597 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
598 WARN_ON(link->status == DL_STATE_ACTIVE);
599 __device_link_del(link);
600 }
601
602 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
603 WARN_ON(link->status != DL_STATE_DORMANT &&
604 link->status != DL_STATE_NONE);
605 __device_link_del(link);
606 }
607
608 device_links_write_unlock();
609 }
610
611 /* Device links support end. */
612
613 int (*platform_notify)(struct device *dev) = NULL;
614 int (*platform_notify_remove)(struct device *dev) = NULL;
615 static struct kobject *dev_kobj;
616 struct kobject *sysfs_dev_char_kobj;
617 struct kobject *sysfs_dev_block_kobj;
618
619 static DEFINE_MUTEX(device_hotplug_lock);
620
621 void lock_device_hotplug(void)
622 {
623 mutex_lock(&device_hotplug_lock);
624 }
625
626 void unlock_device_hotplug(void)
627 {
628 mutex_unlock(&device_hotplug_lock);
629 }
630
631 int lock_device_hotplug_sysfs(void)
632 {
633 if (mutex_trylock(&device_hotplug_lock))
634 return 0;
635
636 /* Avoid busy looping (5 ms of sleep should do). */
637 msleep(5);
638 return restart_syscall();
639 }
640
641 #ifdef CONFIG_BLOCK
642 static inline int device_is_not_partition(struct device *dev)
643 {
644 return !(dev->type == &part_type);
645 }
646 #else
647 static inline int device_is_not_partition(struct device *dev)
648 {
649 return 1;
650 }
651 #endif
652
653 /**
654 * dev_driver_string - Return a device's driver name, if at all possible
655 * @dev: struct device to get the name of
656 *
657 * Will return the device's driver's name if it is bound to a device. If
658 * the device is not bound to a driver, it will return the name of the bus
659 * it is attached to. If it is not attached to a bus either, an empty
660 * string will be returned.
661 */
662 const char *dev_driver_string(const struct device *dev)
663 {
664 struct device_driver *drv;
665
666 /* dev->driver can change to NULL underneath us because of unbinding,
667 * so be careful about accessing it. dev->bus and dev->class should
668 * never change once they are set, so they don't need special care.
669 */
670 drv = ACCESS_ONCE(dev->driver);
671 return drv ? drv->name :
672 (dev->bus ? dev->bus->name :
673 (dev->class ? dev->class->name : ""));
674 }
675 EXPORT_SYMBOL(dev_driver_string);
676
677 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
678
679 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
680 char *buf)
681 {
682 struct device_attribute *dev_attr = to_dev_attr(attr);
683 struct device *dev = kobj_to_dev(kobj);
684 ssize_t ret = -EIO;
685
686 if (dev_attr->show)
687 ret = dev_attr->show(dev, dev_attr, buf);
688 if (ret >= (ssize_t)PAGE_SIZE) {
689 print_symbol("dev_attr_show: %s returned bad count\n",
690 (unsigned long)dev_attr->show);
691 }
692 return ret;
693 }
694
695 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
696 const char *buf, size_t count)
697 {
698 struct device_attribute *dev_attr = to_dev_attr(attr);
699 struct device *dev = kobj_to_dev(kobj);
700 ssize_t ret = -EIO;
701
702 if (dev_attr->store)
703 ret = dev_attr->store(dev, dev_attr, buf, count);
704 return ret;
705 }
706
707 static const struct sysfs_ops dev_sysfs_ops = {
708 .show = dev_attr_show,
709 .store = dev_attr_store,
710 };
711
712 #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
713
714 ssize_t device_store_ulong(struct device *dev,
715 struct device_attribute *attr,
716 const char *buf, size_t size)
717 {
718 struct dev_ext_attribute *ea = to_ext_attr(attr);
719 char *end;
720 unsigned long new = simple_strtoul(buf, &end, 0);
721 if (end == buf)
722 return -EINVAL;
723 *(unsigned long *)(ea->var) = new;
724 /* Always return full write size even if we didn't consume all */
725 return size;
726 }
727 EXPORT_SYMBOL_GPL(device_store_ulong);
728
729 ssize_t device_show_ulong(struct device *dev,
730 struct device_attribute *attr,
731 char *buf)
732 {
733 struct dev_ext_attribute *ea = to_ext_attr(attr);
734 return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
735 }
736 EXPORT_SYMBOL_GPL(device_show_ulong);
737
738 ssize_t device_store_int(struct device *dev,
739 struct device_attribute *attr,
740 const char *buf, size_t size)
741 {
742 struct dev_ext_attribute *ea = to_ext_attr(attr);
743 char *end;
744 long new = simple_strtol(buf, &end, 0);
745 if (end == buf || new > INT_MAX || new < INT_MIN)
746 return -EINVAL;
747 *(int *)(ea->var) = new;
748 /* Always return full write size even if we didn't consume all */
749 return size;
750 }
751 EXPORT_SYMBOL_GPL(device_store_int);
752
753 ssize_t device_show_int(struct device *dev,
754 struct device_attribute *attr,
755 char *buf)
756 {
757 struct dev_ext_attribute *ea = to_ext_attr(attr);
758
759 return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
760 }
761 EXPORT_SYMBOL_GPL(device_show_int);
762
763 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
764 const char *buf, size_t size)
765 {
766 struct dev_ext_attribute *ea = to_ext_attr(attr);
767
768 if (strtobool(buf, ea->var) < 0)
769 return -EINVAL;
770
771 return size;
772 }
773 EXPORT_SYMBOL_GPL(device_store_bool);
774
775 ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
776 char *buf)
777 {
778 struct dev_ext_attribute *ea = to_ext_attr(attr);
779
780 return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
781 }
782 EXPORT_SYMBOL_GPL(device_show_bool);
783
784 /**
785 * device_release - free device structure.
786 * @kobj: device's kobject.
787 *
788 * This is called once the reference count for the object
789 * reaches 0. We forward the call to the device's release
790 * method, which should handle actually freeing the structure.
791 */
792 static void device_release(struct kobject *kobj)
793 {
794 struct device *dev = kobj_to_dev(kobj);
795 struct device_private *p = dev->p;
796
797 /*
798 * Some platform devices are driven without driver attached
799 * and managed resources may have been acquired. Make sure
800 * all resources are released.
801 *
802 * Drivers still can add resources into device after device
803 * is deleted but alive, so release devres here to avoid
804 * possible memory leak.
805 */
806 devres_release_all(dev);
807
808 if (dev->release)
809 dev->release(dev);
810 else if (dev->type && dev->type->release)
811 dev->type->release(dev);
812 else if (dev->class && dev->class->dev_release)
813 dev->class->dev_release(dev);
814 else
815 WARN(1, KERN_ERR "Device '%s' does not have a release() "
816 "function, it is broken and must be fixed.\n",
817 dev_name(dev));
818 kfree(p);
819 }
820
821 static const void *device_namespace(struct kobject *kobj)
822 {
823 struct device *dev = kobj_to_dev(kobj);
824 const void *ns = NULL;
825
826 if (dev->class && dev->class->ns_type)
827 ns = dev->class->namespace(dev);
828
829 return ns;
830 }
831
832 static struct kobj_type device_ktype = {
833 .release = device_release,
834 .sysfs_ops = &dev_sysfs_ops,
835 .namespace = device_namespace,
836 };
837
838
839 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
840 {
841 struct kobj_type *ktype = get_ktype(kobj);
842
843 if (ktype == &device_ktype) {
844 struct device *dev = kobj_to_dev(kobj);
845 if (dev->bus)
846 return 1;
847 if (dev->class)
848 return 1;
849 }
850 return 0;
851 }
852
853 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
854 {
855 struct device *dev = kobj_to_dev(kobj);
856
857 if (dev->bus)
858 return dev->bus->name;
859 if (dev->class)
860 return dev->class->name;
861 return NULL;
862 }
863
864 static int dev_uevent(struct kset *kset, struct kobject *kobj,
865 struct kobj_uevent_env *env)
866 {
867 struct device *dev = kobj_to_dev(kobj);
868 int retval = 0;
869
870 /* add device node properties if present */
871 if (MAJOR(dev->devt)) {
872 const char *tmp;
873 const char *name;
874 umode_t mode = 0;
875 kuid_t uid = GLOBAL_ROOT_UID;
876 kgid_t gid = GLOBAL_ROOT_GID;
877
878 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
879 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
880 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
881 if (name) {
882 add_uevent_var(env, "DEVNAME=%s", name);
883 if (mode)
884 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
885 if (!uid_eq(uid, GLOBAL_ROOT_UID))
886 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
887 if (!gid_eq(gid, GLOBAL_ROOT_GID))
888 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
889 kfree(tmp);
890 }
891 }
892
893 if (dev->type && dev->type->name)
894 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
895
896 if (dev->driver)
897 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
898
899 /* Add common DT information about the device */
900 of_device_uevent(dev, env);
901
902 /* have the bus specific function add its stuff */
903 if (dev->bus && dev->bus->uevent) {
904 retval = dev->bus->uevent(dev, env);
905 if (retval)
906 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
907 dev_name(dev), __func__, retval);
908 }
909
910 /* have the class specific function add its stuff */
911 if (dev->class && dev->class->dev_uevent) {
912 retval = dev->class->dev_uevent(dev, env);
913 if (retval)
914 pr_debug("device: '%s': %s: class uevent() "
915 "returned %d\n", dev_name(dev),
916 __func__, retval);
917 }
918
919 /* have the device type specific function add its stuff */
920 if (dev->type && dev->type->uevent) {
921 retval = dev->type->uevent(dev, env);
922 if (retval)
923 pr_debug("device: '%s': %s: dev_type uevent() "
924 "returned %d\n", dev_name(dev),
925 __func__, retval);
926 }
927
928 return retval;
929 }
930
931 static const struct kset_uevent_ops device_uevent_ops = {
932 .filter = dev_uevent_filter,
933 .name = dev_uevent_name,
934 .uevent = dev_uevent,
935 };
936
937 static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
938 char *buf)
939 {
940 struct kobject *top_kobj;
941 struct kset *kset;
942 struct kobj_uevent_env *env = NULL;
943 int i;
944 size_t count = 0;
945 int retval;
946
947 /* search the kset, the device belongs to */
948 top_kobj = &dev->kobj;
949 while (!top_kobj->kset && top_kobj->parent)
950 top_kobj = top_kobj->parent;
951 if (!top_kobj->kset)
952 goto out;
953
954 kset = top_kobj->kset;
955 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
956 goto out;
957
958 /* respect filter */
959 if (kset->uevent_ops && kset->uevent_ops->filter)
960 if (!kset->uevent_ops->filter(kset, &dev->kobj))
961 goto out;
962
963 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
964 if (!env)
965 return -ENOMEM;
966
967 /* let the kset specific function add its keys */
968 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
969 if (retval)
970 goto out;
971
972 /* copy keys to file */
973 for (i = 0; i < env->envp_idx; i++)
974 count += sprintf(&buf[count], "%s\n", env->envp[i]);
975 out:
976 kfree(env);
977 return count;
978 }
979
980 static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
981 const char *buf, size_t count)
982 {
983 enum kobject_action action;
984
985 if (kobject_action_type(buf, count, &action) == 0)
986 kobject_uevent(&dev->kobj, action);
987 else
988 dev_err(dev, "uevent: unknown action-string\n");
989 return count;
990 }
991 static DEVICE_ATTR_RW(uevent);
992
993 static ssize_t online_show(struct device *dev, struct device_attribute *attr,
994 char *buf)
995 {
996 bool val;
997
998 device_lock(dev);
999 val = !dev->offline;
1000 device_unlock(dev);
1001 return sprintf(buf, "%u\n", val);
1002 }
1003
1004 static ssize_t online_store(struct device *dev, struct device_attribute *attr,
1005 const char *buf, size_t count)
1006 {
1007 bool val;
1008 int ret;
1009
1010 ret = strtobool(buf, &val);
1011 if (ret < 0)
1012 return ret;
1013
1014 ret = lock_device_hotplug_sysfs();
1015 if (ret)
1016 return ret;
1017
1018 ret = val ? device_online(dev) : device_offline(dev);
1019 unlock_device_hotplug();
1020 return ret < 0 ? ret : count;
1021 }
1022 static DEVICE_ATTR_RW(online);
1023
1024 int device_add_groups(struct device *dev, const struct attribute_group **groups)
1025 {
1026 return sysfs_create_groups(&dev->kobj, groups);
1027 }
1028
1029 void device_remove_groups(struct device *dev,
1030 const struct attribute_group **groups)
1031 {
1032 sysfs_remove_groups(&dev->kobj, groups);
1033 }
1034
1035 static int device_add_attrs(struct device *dev)
1036 {
1037 struct class *class = dev->class;
1038 const struct device_type *type = dev->type;
1039 int error;
1040
1041 if (class) {
1042 error = device_add_groups(dev, class->dev_groups);
1043 if (error)
1044 return error;
1045 }
1046
1047 if (type) {
1048 error = device_add_groups(dev, type->groups);
1049 if (error)
1050 goto err_remove_class_groups;
1051 }
1052
1053 error = device_add_groups(dev, dev->groups);
1054 if (error)
1055 goto err_remove_type_groups;
1056
1057 if (device_supports_offline(dev) && !dev->offline_disabled) {
1058 error = device_create_file(dev, &dev_attr_online);
1059 if (error)
1060 goto err_remove_dev_groups;
1061 }
1062
1063 error = device_create_file(dev, &dev_attr_deferred_probe);
1064 if (error)
1065 goto err_remove_online;
1066
1067 return 0;
1068
1069 err_remove_online:
1070 device_remove_file(dev, &dev_attr_online);
1071 err_remove_dev_groups:
1072 device_remove_groups(dev, dev->groups);
1073 err_remove_type_groups:
1074 if (type)
1075 device_remove_groups(dev, type->groups);
1076 err_remove_class_groups:
1077 if (class)
1078 device_remove_groups(dev, class->dev_groups);
1079
1080 return error;
1081 }
1082
1083 static void device_remove_attrs(struct device *dev)
1084 {
1085 struct class *class = dev->class;
1086 const struct device_type *type = dev->type;
1087
1088 device_remove_file(dev, &dev_attr_deferred_probe);
1089 device_remove_file(dev, &dev_attr_online);
1090 device_remove_groups(dev, dev->groups);
1091
1092 if (type)
1093 device_remove_groups(dev, type->groups);
1094
1095 if (class)
1096 device_remove_groups(dev, class->dev_groups);
1097 }
1098
1099 static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
1100 char *buf)
1101 {
1102 return print_dev_t(buf, dev->devt);
1103 }
1104 static DEVICE_ATTR_RO(dev);
1105
1106 /* /sys/devices/ */
1107 struct kset *devices_kset;
1108
1109 /**
1110 * devices_kset_move_before - Move device in the devices_kset's list.
1111 * @deva: Device to move.
1112 * @devb: Device @deva should come before.
1113 */
1114 static void devices_kset_move_before(struct device *deva, struct device *devb)
1115 {
1116 if (!devices_kset)
1117 return;
1118 pr_debug("devices_kset: Moving %s before %s\n",
1119 dev_name(deva), dev_name(devb));
1120 spin_lock(&devices_kset->list_lock);
1121 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
1122 spin_unlock(&devices_kset->list_lock);
1123 }
1124
1125 /**
1126 * devices_kset_move_after - Move device in the devices_kset's list.
1127 * @deva: Device to move
1128 * @devb: Device @deva should come after.
1129 */
1130 static void devices_kset_move_after(struct device *deva, struct device *devb)
1131 {
1132 if (!devices_kset)
1133 return;
1134 pr_debug("devices_kset: Moving %s after %s\n",
1135 dev_name(deva), dev_name(devb));
1136 spin_lock(&devices_kset->list_lock);
1137 list_move(&deva->kobj.entry, &devb->kobj.entry);
1138 spin_unlock(&devices_kset->list_lock);
1139 }
1140
1141 /**
1142 * devices_kset_move_last - move the device to the end of devices_kset's list.
1143 * @dev: device to move
1144 */
1145 void devices_kset_move_last(struct device *dev)
1146 {
1147 if (!devices_kset)
1148 return;
1149 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
1150 spin_lock(&devices_kset->list_lock);
1151 list_move_tail(&dev->kobj.entry, &devices_kset->list);
1152 spin_unlock(&devices_kset->list_lock);
1153 }
1154
1155 /**
1156 * device_create_file - create sysfs attribute file for device.
1157 * @dev: device.
1158 * @attr: device attribute descriptor.
1159 */
1160 int device_create_file(struct device *dev,
1161 const struct device_attribute *attr)
1162 {
1163 int error = 0;
1164
1165 if (dev) {
1166 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
1167 "Attribute %s: write permission without 'store'\n",
1168 attr->attr.name);
1169 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
1170 "Attribute %s: read permission without 'show'\n",
1171 attr->attr.name);
1172 error = sysfs_create_file(&dev->kobj, &attr->attr);
1173 }
1174
1175 return error;
1176 }
1177 EXPORT_SYMBOL_GPL(device_create_file);
1178
1179 /**
1180 * device_remove_file - remove sysfs attribute file.
1181 * @dev: device.
1182 * @attr: device attribute descriptor.
1183 */
1184 void device_remove_file(struct device *dev,
1185 const struct device_attribute *attr)
1186 {
1187 if (dev)
1188 sysfs_remove_file(&dev->kobj, &attr->attr);
1189 }
1190 EXPORT_SYMBOL_GPL(device_remove_file);
1191
1192 /**
1193 * device_remove_file_self - remove sysfs attribute file from its own method.
1194 * @dev: device.
1195 * @attr: device attribute descriptor.
1196 *
1197 * See kernfs_remove_self() for details.
1198 */
1199 bool device_remove_file_self(struct device *dev,
1200 const struct device_attribute *attr)
1201 {
1202 if (dev)
1203 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
1204 else
1205 return false;
1206 }
1207 EXPORT_SYMBOL_GPL(device_remove_file_self);
1208
1209 /**
1210 * device_create_bin_file - create sysfs binary attribute file for device.
1211 * @dev: device.
1212 * @attr: device binary attribute descriptor.
1213 */
1214 int device_create_bin_file(struct device *dev,
1215 const struct bin_attribute *attr)
1216 {
1217 int error = -EINVAL;
1218 if (dev)
1219 error = sysfs_create_bin_file(&dev->kobj, attr);
1220 return error;
1221 }
1222 EXPORT_SYMBOL_GPL(device_create_bin_file);
1223
1224 /**
1225 * device_remove_bin_file - remove sysfs binary attribute file
1226 * @dev: device.
1227 * @attr: device binary attribute descriptor.
1228 */
1229 void device_remove_bin_file(struct device *dev,
1230 const struct bin_attribute *attr)
1231 {
1232 if (dev)
1233 sysfs_remove_bin_file(&dev->kobj, attr);
1234 }
1235 EXPORT_SYMBOL_GPL(device_remove_bin_file);
1236
1237 static void klist_children_get(struct klist_node *n)
1238 {
1239 struct device_private *p = to_device_private_parent(n);
1240 struct device *dev = p->device;
1241
1242 get_device(dev);
1243 }
1244
1245 static void klist_children_put(struct klist_node *n)
1246 {
1247 struct device_private *p = to_device_private_parent(n);
1248 struct device *dev = p->device;
1249
1250 put_device(dev);
1251 }
1252
1253 /**
1254 * device_initialize - init device structure.
1255 * @dev: device.
1256 *
1257 * This prepares the device for use by other layers by initializing
1258 * its fields.
1259 * It is the first half of device_register(), if called by
1260 * that function, though it can also be called separately, so one
1261 * may use @dev's fields. In particular, get_device()/put_device()
1262 * may be used for reference counting of @dev after calling this
1263 * function.
1264 *
1265 * All fields in @dev must be initialized by the caller to 0, except
1266 * for those explicitly set to some other value. The simplest
1267 * approach is to use kzalloc() to allocate the structure containing
1268 * @dev.
1269 *
1270 * NOTE: Use put_device() to give up your reference instead of freeing
1271 * @dev directly once you have called this function.
1272 */
1273 void device_initialize(struct device *dev)
1274 {
1275 dev->kobj.kset = devices_kset;
1276 kobject_init(&dev->kobj, &device_ktype);
1277 INIT_LIST_HEAD(&dev->dma_pools);
1278 mutex_init(&dev->mutex);
1279 lockdep_set_novalidate_class(&dev->mutex);
1280 spin_lock_init(&dev->devres_lock);
1281 INIT_LIST_HEAD(&dev->devres_head);
1282 device_pm_init(dev);
1283 set_dev_node(dev, -1);
1284 #ifdef CONFIG_GENERIC_MSI_IRQ
1285 INIT_LIST_HEAD(&dev->msi_list);
1286 #endif
1287 INIT_LIST_HEAD(&dev->links.consumers);
1288 INIT_LIST_HEAD(&dev->links.suppliers);
1289 dev->links.status = DL_DEV_NO_DRIVER;
1290 }
1291 EXPORT_SYMBOL_GPL(device_initialize);
1292
1293 struct kobject *virtual_device_parent(struct device *dev)
1294 {
1295 static struct kobject *virtual_dir = NULL;
1296
1297 if (!virtual_dir)
1298 virtual_dir = kobject_create_and_add("virtual",
1299 &devices_kset->kobj);
1300
1301 return virtual_dir;
1302 }
1303
1304 struct class_dir {
1305 struct kobject kobj;
1306 struct class *class;
1307 };
1308
1309 #define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
1310
1311 static void class_dir_release(struct kobject *kobj)
1312 {
1313 struct class_dir *dir = to_class_dir(kobj);
1314 kfree(dir);
1315 }
1316
1317 static const
1318 struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
1319 {
1320 struct class_dir *dir = to_class_dir(kobj);
1321 return dir->class->ns_type;
1322 }
1323
1324 static struct kobj_type class_dir_ktype = {
1325 .release = class_dir_release,
1326 .sysfs_ops = &kobj_sysfs_ops,
1327 .child_ns_type = class_dir_child_ns_type
1328 };
1329
1330 static struct kobject *
1331 class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
1332 {
1333 struct class_dir *dir;
1334 int retval;
1335
1336 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1337 if (!dir)
1338 return NULL;
1339
1340 dir->class = class;
1341 kobject_init(&dir->kobj, &class_dir_ktype);
1342
1343 dir->kobj.kset = &class->p->glue_dirs;
1344
1345 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
1346 if (retval < 0) {
1347 kobject_put(&dir->kobj);
1348 return NULL;
1349 }
1350 return &dir->kobj;
1351 }
1352
1353 static DEFINE_MUTEX(gdp_mutex);
1354
1355 static struct kobject *get_device_parent(struct device *dev,
1356 struct device *parent)
1357 {
1358 if (dev->class) {
1359 struct kobject *kobj = NULL;
1360 struct kobject *parent_kobj;
1361 struct kobject *k;
1362
1363 #ifdef CONFIG_BLOCK
1364 /* block disks show up in /sys/block */
1365 if (sysfs_deprecated && dev->class == &block_class) {
1366 if (parent && parent->class == &block_class)
1367 return &parent->kobj;
1368 return &block_class.p->subsys.kobj;
1369 }
1370 #endif
1371
1372 /*
1373 * If we have no parent, we live in "virtual".
1374 * Class-devices with a non class-device as parent, live
1375 * in a "glue" directory to prevent namespace collisions.
1376 */
1377 if (parent == NULL)
1378 parent_kobj = virtual_device_parent(dev);
1379 else if (parent->class && !dev->class->ns_type)
1380 return &parent->kobj;
1381 else
1382 parent_kobj = &parent->kobj;
1383
1384 mutex_lock(&gdp_mutex);
1385
1386 /* find our class-directory at the parent and reference it */
1387 spin_lock(&dev->class->p->glue_dirs.list_lock);
1388 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
1389 if (k->parent == parent_kobj) {
1390 kobj = kobject_get(k);
1391 break;
1392 }
1393 spin_unlock(&dev->class->p->glue_dirs.list_lock);
1394 if (kobj) {
1395 mutex_unlock(&gdp_mutex);
1396 return kobj;
1397 }
1398
1399 /* or create a new class-directory at the parent device */
1400 k = class_dir_create_and_add(dev->class, parent_kobj);
1401 /* do not emit an uevent for this simple "glue" directory */
1402 mutex_unlock(&gdp_mutex);
1403 return k;
1404 }
1405
1406 /* subsystems can specify a default root directory for their devices */
1407 if (!parent && dev->bus && dev->bus->dev_root)
1408 return &dev->bus->dev_root->kobj;
1409
1410 if (parent)
1411 return &parent->kobj;
1412 return NULL;
1413 }
1414
1415 static inline bool live_in_glue_dir(struct kobject *kobj,
1416 struct device *dev)
1417 {
1418 if (!kobj || !dev->class ||
1419 kobj->kset != &dev->class->p->glue_dirs)
1420 return false;
1421 return true;
1422 }
1423
1424 static inline struct kobject *get_glue_dir(struct device *dev)
1425 {
1426 return dev->kobj.parent;
1427 }
1428
1429 /*
1430 * make sure cleaning up dir as the last step, we need to make
1431 * sure .release handler of kobject is run with holding the
1432 * global lock
1433 */
1434 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
1435 {
1436 /* see if we live in a "glue" directory */
1437 if (!live_in_glue_dir(glue_dir, dev))
1438 return;
1439
1440 mutex_lock(&gdp_mutex);
1441 kobject_put(glue_dir);
1442 mutex_unlock(&gdp_mutex);
1443 }
1444
1445 static int device_add_class_symlinks(struct device *dev)
1446 {
1447 struct device_node *of_node = dev_of_node(dev);
1448 int error;
1449
1450 if (of_node) {
1451 error = sysfs_create_link(&dev->kobj, &of_node->kobj,"of_node");
1452 if (error)
1453 dev_warn(dev, "Error %d creating of_node link\n",error);
1454 /* An error here doesn't warrant bringing down the device */
1455 }
1456
1457 if (!dev->class)
1458 return 0;
1459
1460 error = sysfs_create_link(&dev->kobj,
1461 &dev->class->p->subsys.kobj,
1462 "subsystem");
1463 if (error)
1464 goto out_devnode;
1465
1466 if (dev->parent && device_is_not_partition(dev)) {
1467 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
1468 "device");
1469 if (error)
1470 goto out_subsys;
1471 }
1472
1473 #ifdef CONFIG_BLOCK
1474 /* /sys/block has directories and does not need symlinks */
1475 if (sysfs_deprecated && dev->class == &block_class)
1476 return 0;
1477 #endif
1478
1479 /* link in the class directory pointing to the device */
1480 error = sysfs_create_link(&dev->class->p->subsys.kobj,
1481 &dev->kobj, dev_name(dev));
1482 if (error)
1483 goto out_device;
1484
1485 return 0;
1486
1487 out_device:
1488 sysfs_remove_link(&dev->kobj, "device");
1489
1490 out_subsys:
1491 sysfs_remove_link(&dev->kobj, "subsystem");
1492 out_devnode:
1493 sysfs_remove_link(&dev->kobj, "of_node");
1494 return error;
1495 }
1496
1497 static void device_remove_class_symlinks(struct device *dev)
1498 {
1499 if (dev_of_node(dev))
1500 sysfs_remove_link(&dev->kobj, "of_node");
1501
1502 if (!dev->class)
1503 return;
1504
1505 if (dev->parent && device_is_not_partition(dev))
1506 sysfs_remove_link(&dev->kobj, "device");
1507 sysfs_remove_link(&dev->kobj, "subsystem");
1508 #ifdef CONFIG_BLOCK
1509 if (sysfs_deprecated && dev->class == &block_class)
1510 return;
1511 #endif
1512 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
1513 }
1514
1515 /**
1516 * dev_set_name - set a device name
1517 * @dev: device
1518 * @fmt: format string for the device's name
1519 */
1520 int dev_set_name(struct device *dev, const char *fmt, ...)
1521 {
1522 va_list vargs;
1523 int err;
1524
1525 va_start(vargs, fmt);
1526 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
1527 va_end(vargs);
1528 return err;
1529 }
1530 EXPORT_SYMBOL_GPL(dev_set_name);
1531
1532 /**
1533 * device_to_dev_kobj - select a /sys/dev/ directory for the device
1534 * @dev: device
1535 *
1536 * By default we select char/ for new entries. Setting class->dev_obj
1537 * to NULL prevents an entry from being created. class->dev_kobj must
1538 * be set (or cleared) before any devices are registered to the class
1539 * otherwise device_create_sys_dev_entry() and
1540 * device_remove_sys_dev_entry() will disagree about the presence of
1541 * the link.
1542 */
1543 static struct kobject *device_to_dev_kobj(struct device *dev)
1544 {
1545 struct kobject *kobj;
1546
1547 if (dev->class)
1548 kobj = dev->class->dev_kobj;
1549 else
1550 kobj = sysfs_dev_char_kobj;
1551
1552 return kobj;
1553 }
1554
1555 static int device_create_sys_dev_entry(struct device *dev)
1556 {
1557 struct kobject *kobj = device_to_dev_kobj(dev);
1558 int error = 0;
1559 char devt_str[15];
1560
1561 if (kobj) {
1562 format_dev_t(devt_str, dev->devt);
1563 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
1564 }
1565
1566 return error;
1567 }
1568
1569 static void device_remove_sys_dev_entry(struct device *dev)
1570 {
1571 struct kobject *kobj = device_to_dev_kobj(dev);
1572 char devt_str[15];
1573
1574 if (kobj) {
1575 format_dev_t(devt_str, dev->devt);
1576 sysfs_remove_link(kobj, devt_str);
1577 }
1578 }
1579
1580 int device_private_init(struct device *dev)
1581 {
1582 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
1583 if (!dev->p)
1584 return -ENOMEM;
1585 dev->p->device = dev;
1586 klist_init(&dev->p->klist_children, klist_children_get,
1587 klist_children_put);
1588 INIT_LIST_HEAD(&dev->p->deferred_probe);
1589 return 0;
1590 }
1591
1592 /**
1593 * device_add - add device to device hierarchy.
1594 * @dev: device.
1595 *
1596 * This is part 2 of device_register(), though may be called
1597 * separately _iff_ device_initialize() has been called separately.
1598 *
1599 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
1600 * to the global and sibling lists for the device, then
1601 * adds it to the other relevant subsystems of the driver model.
1602 *
1603 * Do not call this routine or device_register() more than once for
1604 * any device structure. The driver model core is not designed to work
1605 * with devices that get unregistered and then spring back to life.
1606 * (Among other things, it's very hard to guarantee that all references
1607 * to the previous incarnation of @dev have been dropped.) Allocate
1608 * and register a fresh new struct device instead.
1609 *
1610 * NOTE: _Never_ directly free @dev after calling this function, even
1611 * if it returned an error! Always use put_device() to give up your
1612 * reference instead.
1613 */
1614 int device_add(struct device *dev)
1615 {
1616 struct device *parent = NULL;
1617 struct kobject *kobj;
1618 struct class_interface *class_intf;
1619 int error = -EINVAL;
1620 struct kobject *glue_dir = NULL;
1621
1622 dev = get_device(dev);
1623 if (!dev)
1624 goto done;
1625
1626 if (!dev->p) {
1627 error = device_private_init(dev);
1628 if (error)
1629 goto done;
1630 }
1631
1632 /*
1633 * for statically allocated devices, which should all be converted
1634 * some day, we need to initialize the name. We prevent reading back
1635 * the name, and force the use of dev_name()
1636 */
1637 if (dev->init_name) {
1638 dev_set_name(dev, "%s", dev->init_name);
1639 dev->init_name = NULL;
1640 }
1641
1642 /* subsystems can specify simple device enumeration */
1643 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
1644 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
1645
1646 if (!dev_name(dev)) {
1647 error = -EINVAL;
1648 goto name_error;
1649 }
1650
1651 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1652
1653 parent = get_device(dev->parent);
1654 kobj = get_device_parent(dev, parent);
1655 if (kobj)
1656 dev->kobj.parent = kobj;
1657
1658 /* use parent numa_node */
1659 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
1660 set_dev_node(dev, dev_to_node(parent));
1661
1662 /* first, register with generic layer. */
1663 /* we require the name to be set before, and pass NULL */
1664 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
1665 if (error) {
1666 glue_dir = get_glue_dir(dev);
1667 goto Error;
1668 }
1669
1670 /* notify platform of device entry */
1671 if (platform_notify)
1672 platform_notify(dev);
1673
1674 error = device_create_file(dev, &dev_attr_uevent);
1675 if (error)
1676 goto attrError;
1677
1678 error = device_add_class_symlinks(dev);
1679 if (error)
1680 goto SymlinkError;
1681 error = device_add_attrs(dev);
1682 if (error)
1683 goto AttrsError;
1684 error = bus_add_device(dev);
1685 if (error)
1686 goto BusError;
1687 error = dpm_sysfs_add(dev);
1688 if (error)
1689 goto DPMError;
1690 device_pm_add(dev);
1691
1692 if (MAJOR(dev->devt)) {
1693 error = device_create_file(dev, &dev_attr_dev);
1694 if (error)
1695 goto DevAttrError;
1696
1697 error = device_create_sys_dev_entry(dev);
1698 if (error)
1699 goto SysEntryError;
1700
1701 devtmpfs_create_node(dev);
1702 }
1703
1704 /* Notify clients of device addition. This call must come
1705 * after dpm_sysfs_add() and before kobject_uevent().
1706 */
1707 if (dev->bus)
1708 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1709 BUS_NOTIFY_ADD_DEVICE, dev);
1710
1711 kobject_uevent(&dev->kobj, KOBJ_ADD);
1712 bus_probe_device(dev);
1713 if (parent)
1714 klist_add_tail(&dev->p->knode_parent,
1715 &parent->p->klist_children);
1716
1717 if (dev->class) {
1718 mutex_lock(&dev->class->p->mutex);
1719 /* tie the class to the device */
1720 klist_add_tail(&dev->knode_class,
1721 &dev->class->p->klist_devices);
1722
1723 /* notify any interfaces that the device is here */
1724 list_for_each_entry(class_intf,
1725 &dev->class->p->interfaces, node)
1726 if (class_intf->add_dev)
1727 class_intf->add_dev(dev, class_intf);
1728 mutex_unlock(&dev->class->p->mutex);
1729 }
1730 done:
1731 put_device(dev);
1732 return error;
1733 SysEntryError:
1734 if (MAJOR(dev->devt))
1735 device_remove_file(dev, &dev_attr_dev);
1736 DevAttrError:
1737 device_pm_remove(dev);
1738 dpm_sysfs_remove(dev);
1739 DPMError:
1740 bus_remove_device(dev);
1741 BusError:
1742 device_remove_attrs(dev);
1743 AttrsError:
1744 device_remove_class_symlinks(dev);
1745 SymlinkError:
1746 device_remove_file(dev, &dev_attr_uevent);
1747 attrError:
1748 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1749 glue_dir = get_glue_dir(dev);
1750 kobject_del(&dev->kobj);
1751 Error:
1752 cleanup_glue_dir(dev, glue_dir);
1753 put_device(parent);
1754 name_error:
1755 kfree(dev->p);
1756 dev->p = NULL;
1757 goto done;
1758 }
1759 EXPORT_SYMBOL_GPL(device_add);
1760
1761 /**
1762 * device_register - register a device with the system.
1763 * @dev: pointer to the device structure
1764 *
1765 * This happens in two clean steps - initialize the device
1766 * and add it to the system. The two steps can be called
1767 * separately, but this is the easiest and most common.
1768 * I.e. you should only call the two helpers separately if
1769 * have a clearly defined need to use and refcount the device
1770 * before it is added to the hierarchy.
1771 *
1772 * For more information, see the kerneldoc for device_initialize()
1773 * and device_add().
1774 *
1775 * NOTE: _Never_ directly free @dev after calling this function, even
1776 * if it returned an error! Always use put_device() to give up the
1777 * reference initialized in this function instead.
1778 */
1779 int device_register(struct device *dev)
1780 {
1781 device_initialize(dev);
1782 return device_add(dev);
1783 }
1784 EXPORT_SYMBOL_GPL(device_register);
1785
1786 /**
1787 * get_device - increment reference count for device.
1788 * @dev: device.
1789 *
1790 * This simply forwards the call to kobject_get(), though
1791 * we do take care to provide for the case that we get a NULL
1792 * pointer passed in.
1793 */
1794 struct device *get_device(struct device *dev)
1795 {
1796 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
1797 }
1798 EXPORT_SYMBOL_GPL(get_device);
1799
1800 /**
1801 * put_device - decrement reference count.
1802 * @dev: device in question.
1803 */
1804 void put_device(struct device *dev)
1805 {
1806 /* might_sleep(); */
1807 if (dev)
1808 kobject_put(&dev->kobj);
1809 }
1810 EXPORT_SYMBOL_GPL(put_device);
1811
1812 /**
1813 * device_del - delete device from system.
1814 * @dev: device.
1815 *
1816 * This is the first part of the device unregistration
1817 * sequence. This removes the device from the lists we control
1818 * from here, has it removed from the other driver model
1819 * subsystems it was added to in device_add(), and removes it
1820 * from the kobject hierarchy.
1821 *
1822 * NOTE: this should be called manually _iff_ device_add() was
1823 * also called manually.
1824 */
1825 void device_del(struct device *dev)
1826 {
1827 struct device *parent = dev->parent;
1828 struct kobject *glue_dir = NULL;
1829 struct class_interface *class_intf;
1830
1831 /* Notify clients of device removal. This call must come
1832 * before dpm_sysfs_remove().
1833 */
1834 if (dev->bus)
1835 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1836 BUS_NOTIFY_DEL_DEVICE, dev);
1837
1838 device_links_purge(dev);
1839 dpm_sysfs_remove(dev);
1840 if (parent)
1841 klist_del(&dev->p->knode_parent);
1842 if (MAJOR(dev->devt)) {
1843 devtmpfs_delete_node(dev);
1844 device_remove_sys_dev_entry(dev);
1845 device_remove_file(dev, &dev_attr_dev);
1846 }
1847 if (dev->class) {
1848 device_remove_class_symlinks(dev);
1849
1850 mutex_lock(&dev->class->p->mutex);
1851 /* notify any interfaces that the device is now gone */
1852 list_for_each_entry(class_intf,
1853 &dev->class->p->interfaces, node)
1854 if (class_intf->remove_dev)
1855 class_intf->remove_dev(dev, class_intf);
1856 /* remove the device from the class list */
1857 klist_del(&dev->knode_class);
1858 mutex_unlock(&dev->class->p->mutex);
1859 }
1860 device_remove_file(dev, &dev_attr_uevent);
1861 device_remove_attrs(dev);
1862 bus_remove_device(dev);
1863 device_pm_remove(dev);
1864 driver_deferred_probe_del(dev);
1865 device_remove_properties(dev);
1866
1867 /* Notify the platform of the removal, in case they
1868 * need to do anything...
1869 */
1870 if (platform_notify_remove)
1871 platform_notify_remove(dev);
1872 if (dev->bus)
1873 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1874 BUS_NOTIFY_REMOVED_DEVICE, dev);
1875 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1876 glue_dir = get_glue_dir(dev);
1877 kobject_del(&dev->kobj);
1878 cleanup_glue_dir(dev, glue_dir);
1879 put_device(parent);
1880 }
1881 EXPORT_SYMBOL_GPL(device_del);
1882
1883 /**
1884 * device_unregister - unregister device from system.
1885 * @dev: device going away.
1886 *
1887 * We do this in two parts, like we do device_register(). First,
1888 * we remove it from all the subsystems with device_del(), then
1889 * we decrement the reference count via put_device(). If that
1890 * is the final reference count, the device will be cleaned up
1891 * via device_release() above. Otherwise, the structure will
1892 * stick around until the final reference to the device is dropped.
1893 */
1894 void device_unregister(struct device *dev)
1895 {
1896 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1897 device_del(dev);
1898 put_device(dev);
1899 }
1900 EXPORT_SYMBOL_GPL(device_unregister);
1901
1902 static struct device *prev_device(struct klist_iter *i)
1903 {
1904 struct klist_node *n = klist_prev(i);
1905 struct device *dev = NULL;
1906 struct device_private *p;
1907
1908 if (n) {
1909 p = to_device_private_parent(n);
1910 dev = p->device;
1911 }
1912 return dev;
1913 }
1914
1915 static struct device *next_device(struct klist_iter *i)
1916 {
1917 struct klist_node *n = klist_next(i);
1918 struct device *dev = NULL;
1919 struct device_private *p;
1920
1921 if (n) {
1922 p = to_device_private_parent(n);
1923 dev = p->device;
1924 }
1925 return dev;
1926 }
1927
1928 /**
1929 * device_get_devnode - path of device node file
1930 * @dev: device
1931 * @mode: returned file access mode
1932 * @uid: returned file owner
1933 * @gid: returned file group
1934 * @tmp: possibly allocated string
1935 *
1936 * Return the relative path of a possible device node.
1937 * Non-default names may need to allocate a memory to compose
1938 * a name. This memory is returned in tmp and needs to be
1939 * freed by the caller.
1940 */
1941 const char *device_get_devnode(struct device *dev,
1942 umode_t *mode, kuid_t *uid, kgid_t *gid,
1943 const char **tmp)
1944 {
1945 char *s;
1946
1947 *tmp = NULL;
1948
1949 /* the device type may provide a specific name */
1950 if (dev->type && dev->type->devnode)
1951 *tmp = dev->type->devnode(dev, mode, uid, gid);
1952 if (*tmp)
1953 return *tmp;
1954
1955 /* the class may provide a specific name */
1956 if (dev->class && dev->class->devnode)
1957 *tmp = dev->class->devnode(dev, mode);
1958 if (*tmp)
1959 return *tmp;
1960
1961 /* return name without allocation, tmp == NULL */
1962 if (strchr(dev_name(dev), '!') == NULL)
1963 return dev_name(dev);
1964
1965 /* replace '!' in the name with '/' */
1966 s = kstrdup(dev_name(dev), GFP_KERNEL);
1967 if (!s)
1968 return NULL;
1969 strreplace(s, '!', '/');
1970 return *tmp = s;
1971 }
1972
1973 /**
1974 * device_for_each_child - device child iterator.
1975 * @parent: parent struct device.
1976 * @fn: function to be called for each device.
1977 * @data: data for the callback.
1978 *
1979 * Iterate over @parent's child devices, and call @fn for each,
1980 * passing it @data.
1981 *
1982 * We check the return of @fn each time. If it returns anything
1983 * other than 0, we break out and return that value.
1984 */
1985 int device_for_each_child(struct device *parent, void *data,
1986 int (*fn)(struct device *dev, void *data))
1987 {
1988 struct klist_iter i;
1989 struct device *child;
1990 int error = 0;
1991
1992 if (!parent->p)
1993 return 0;
1994
1995 klist_iter_init(&parent->p->klist_children, &i);
1996 while ((child = next_device(&i)) && !error)
1997 error = fn(child, data);
1998 klist_iter_exit(&i);
1999 return error;
2000 }
2001 EXPORT_SYMBOL_GPL(device_for_each_child);
2002
2003 /**
2004 * device_for_each_child_reverse - device child iterator in reversed order.
2005 * @parent: parent struct device.
2006 * @fn: function to be called for each device.
2007 * @data: data for the callback.
2008 *
2009 * Iterate over @parent's child devices, and call @fn for each,
2010 * passing it @data.
2011 *
2012 * We check the return of @fn each time. If it returns anything
2013 * other than 0, we break out and return that value.
2014 */
2015 int device_for_each_child_reverse(struct device *parent, void *data,
2016 int (*fn)(struct device *dev, void *data))
2017 {
2018 struct klist_iter i;
2019 struct device *child;
2020 int error = 0;
2021
2022 if (!parent->p)
2023 return 0;
2024
2025 klist_iter_init(&parent->p->klist_children, &i);
2026 while ((child = prev_device(&i)) && !error)
2027 error = fn(child, data);
2028 klist_iter_exit(&i);
2029 return error;
2030 }
2031 EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
2032
2033 /**
2034 * device_find_child - device iterator for locating a particular device.
2035 * @parent: parent struct device
2036 * @match: Callback function to check device
2037 * @data: Data to pass to match function
2038 *
2039 * This is similar to the device_for_each_child() function above, but it
2040 * returns a reference to a device that is 'found' for later use, as
2041 * determined by the @match callback.
2042 *
2043 * The callback should return 0 if the device doesn't match and non-zero
2044 * if it does. If the callback returns non-zero and a reference to the
2045 * current device can be obtained, this function will return to the caller
2046 * and not iterate over any more devices.
2047 *
2048 * NOTE: you will need to drop the reference with put_device() after use.
2049 */
2050 struct device *device_find_child(struct device *parent, void *data,
2051 int (*match)(struct device *dev, void *data))
2052 {
2053 struct klist_iter i;
2054 struct device *child;
2055
2056 if (!parent)
2057 return NULL;
2058
2059 klist_iter_init(&parent->p->klist_children, &i);
2060 while ((child = next_device(&i)))
2061 if (match(child, data) && get_device(child))
2062 break;
2063 klist_iter_exit(&i);
2064 return child;
2065 }
2066 EXPORT_SYMBOL_GPL(device_find_child);
2067
2068 int __init devices_init(void)
2069 {
2070 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
2071 if (!devices_kset)
2072 return -ENOMEM;
2073 dev_kobj = kobject_create_and_add("dev", NULL);
2074 if (!dev_kobj)
2075 goto dev_kobj_err;
2076 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
2077 if (!sysfs_dev_block_kobj)
2078 goto block_kobj_err;
2079 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
2080 if (!sysfs_dev_char_kobj)
2081 goto char_kobj_err;
2082
2083 return 0;
2084
2085 char_kobj_err:
2086 kobject_put(sysfs_dev_block_kobj);
2087 block_kobj_err:
2088 kobject_put(dev_kobj);
2089 dev_kobj_err:
2090 kset_unregister(devices_kset);
2091 return -ENOMEM;
2092 }
2093
2094 static int device_check_offline(struct device *dev, void *not_used)
2095 {
2096 int ret;
2097
2098 ret = device_for_each_child(dev, NULL, device_check_offline);
2099 if (ret)
2100 return ret;
2101
2102 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
2103 }
2104
2105 /**
2106 * device_offline - Prepare the device for hot-removal.
2107 * @dev: Device to be put offline.
2108 *
2109 * Execute the device bus type's .offline() callback, if present, to prepare
2110 * the device for a subsequent hot-removal. If that succeeds, the device must
2111 * not be used until either it is removed or its bus type's .online() callback
2112 * is executed.
2113 *
2114 * Call under device_hotplug_lock.
2115 */
2116 int device_offline(struct device *dev)
2117 {
2118 int ret;
2119
2120 if (dev->offline_disabled)
2121 return -EPERM;
2122
2123 ret = device_for_each_child(dev, NULL, device_check_offline);
2124 if (ret)
2125 return ret;
2126
2127 device_lock(dev);
2128 if (device_supports_offline(dev)) {
2129 if (dev->offline) {
2130 ret = 1;
2131 } else {
2132 ret = dev->bus->offline(dev);
2133 if (!ret) {
2134 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
2135 dev->offline = true;
2136 }
2137 }
2138 }
2139 device_unlock(dev);
2140
2141 return ret;
2142 }
2143
2144 /**
2145 * device_online - Put the device back online after successful device_offline().
2146 * @dev: Device to be put back online.
2147 *
2148 * If device_offline() has been successfully executed for @dev, but the device
2149 * has not been removed subsequently, execute its bus type's .online() callback
2150 * to indicate that the device can be used again.
2151 *
2152 * Call under device_hotplug_lock.
2153 */
2154 int device_online(struct device *dev)
2155 {
2156 int ret = 0;
2157
2158 device_lock(dev);
2159 if (device_supports_offline(dev)) {
2160 if (dev->offline) {
2161 ret = dev->bus->online(dev);
2162 if (!ret) {
2163 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
2164 dev->offline = false;
2165 }
2166 } else {
2167 ret = 1;
2168 }
2169 }
2170 device_unlock(dev);
2171
2172 return ret;
2173 }
2174
2175 struct root_device {
2176 struct device dev;
2177 struct module *owner;
2178 };
2179
2180 static inline struct root_device *to_root_device(struct device *d)
2181 {
2182 return container_of(d, struct root_device, dev);
2183 }
2184
2185 static void root_device_release(struct device *dev)
2186 {
2187 kfree(to_root_device(dev));
2188 }
2189
2190 /**
2191 * __root_device_register - allocate and register a root device
2192 * @name: root device name
2193 * @owner: owner module of the root device, usually THIS_MODULE
2194 *
2195 * This function allocates a root device and registers it
2196 * using device_register(). In order to free the returned
2197 * device, use root_device_unregister().
2198 *
2199 * Root devices are dummy devices which allow other devices
2200 * to be grouped under /sys/devices. Use this function to
2201 * allocate a root device and then use it as the parent of
2202 * any device which should appear under /sys/devices/{name}
2203 *
2204 * The /sys/devices/{name} directory will also contain a
2205 * 'module' symlink which points to the @owner directory
2206 * in sysfs.
2207 *
2208 * Returns &struct device pointer on success, or ERR_PTR() on error.
2209 *
2210 * Note: You probably want to use root_device_register().
2211 */
2212 struct device *__root_device_register(const char *name, struct module *owner)
2213 {
2214 struct root_device *root;
2215 int err = -ENOMEM;
2216
2217 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
2218 if (!root)
2219 return ERR_PTR(err);
2220
2221 err = dev_set_name(&root->dev, "%s", name);
2222 if (err) {
2223 kfree(root);
2224 return ERR_PTR(err);
2225 }
2226
2227 root->dev.release = root_device_release;
2228
2229 err = device_register(&root->dev);
2230 if (err) {
2231 put_device(&root->dev);
2232 return ERR_PTR(err);
2233 }
2234
2235 #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
2236 if (owner) {
2237 struct module_kobject *mk = &owner->mkobj;
2238
2239 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
2240 if (err) {
2241 device_unregister(&root->dev);
2242 return ERR_PTR(err);
2243 }
2244 root->owner = owner;
2245 }
2246 #endif
2247
2248 return &root->dev;
2249 }
2250 EXPORT_SYMBOL_GPL(__root_device_register);
2251
2252 /**
2253 * root_device_unregister - unregister and free a root device
2254 * @dev: device going away
2255 *
2256 * This function unregisters and cleans up a device that was created by
2257 * root_device_register().
2258 */
2259 void root_device_unregister(struct device *dev)
2260 {
2261 struct root_device *root = to_root_device(dev);
2262
2263 if (root->owner)
2264 sysfs_remove_link(&root->dev.kobj, "module");
2265
2266 device_unregister(dev);
2267 }
2268 EXPORT_SYMBOL_GPL(root_device_unregister);
2269
2270
2271 static void device_create_release(struct device *dev)
2272 {
2273 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
2274 kfree(dev);
2275 }
2276
2277 static struct device *
2278 device_create_groups_vargs(struct class *class, struct device *parent,
2279 dev_t devt, void *drvdata,
2280 const struct attribute_group **groups,
2281 const char *fmt, va_list args)
2282 {
2283 struct device *dev = NULL;
2284 int retval = -ENODEV;
2285
2286 if (class == NULL || IS_ERR(class))
2287 goto error;
2288
2289 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2290 if (!dev) {
2291 retval = -ENOMEM;
2292 goto error;
2293 }
2294
2295 device_initialize(dev);
2296 dev->devt = devt;
2297 dev->class = class;
2298 dev->parent = parent;
2299 dev->groups = groups;
2300 dev->release = device_create_release;
2301 dev_set_drvdata(dev, drvdata);
2302
2303 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
2304 if (retval)
2305 goto error;
2306
2307 retval = device_add(dev);
2308 if (retval)
2309 goto error;
2310
2311 return dev;
2312
2313 error:
2314 put_device(dev);
2315 return ERR_PTR(retval);
2316 }
2317
2318 /**
2319 * device_create_vargs - creates a device and registers it with sysfs
2320 * @class: pointer to the struct class that this device should be registered to
2321 * @parent: pointer to the parent struct device of this new device, if any
2322 * @devt: the dev_t for the char device to be added
2323 * @drvdata: the data to be added to the device for callbacks
2324 * @fmt: string for the device's name
2325 * @args: va_list for the device's name
2326 *
2327 * This function can be used by char device classes. A struct device
2328 * will be created in sysfs, registered to the specified class.
2329 *
2330 * A "dev" file will be created, showing the dev_t for the device, if
2331 * the dev_t is not 0,0.
2332 * If a pointer to a parent struct device is passed in, the newly created
2333 * struct device will be a child of that device in sysfs.
2334 * The pointer to the struct device will be returned from the call.
2335 * Any further sysfs files that might be required can be created using this
2336 * pointer.
2337 *
2338 * Returns &struct device pointer on success, or ERR_PTR() on error.
2339 *
2340 * Note: the struct class passed to this function must have previously
2341 * been created with a call to class_create().
2342 */
2343 struct device *device_create_vargs(struct class *class, struct device *parent,
2344 dev_t devt, void *drvdata, const char *fmt,
2345 va_list args)
2346 {
2347 return device_create_groups_vargs(class, parent, devt, drvdata, NULL,
2348 fmt, args);
2349 }
2350 EXPORT_SYMBOL_GPL(device_create_vargs);
2351
2352 /**
2353 * device_create - creates a device and registers it with sysfs
2354 * @class: pointer to the struct class that this device should be registered to
2355 * @parent: pointer to the parent struct device of this new device, if any
2356 * @devt: the dev_t for the char device to be added
2357 * @drvdata: the data to be added to the device for callbacks
2358 * @fmt: string for the device's name
2359 *
2360 * This function can be used by char device classes. A struct device
2361 * will be created in sysfs, registered to the specified class.
2362 *
2363 * A "dev" file will be created, showing the dev_t for the device, if
2364 * the dev_t is not 0,0.
2365 * If a pointer to a parent struct device is passed in, the newly created
2366 * struct device will be a child of that device in sysfs.
2367 * The pointer to the struct device will be returned from the call.
2368 * Any further sysfs files that might be required can be created using this
2369 * pointer.
2370 *
2371 * Returns &struct device pointer on success, or ERR_PTR() on error.
2372 *
2373 * Note: the struct class passed to this function must have previously
2374 * been created with a call to class_create().
2375 */
2376 struct device *device_create(struct class *class, struct device *parent,
2377 dev_t devt, void *drvdata, const char *fmt, ...)
2378 {
2379 va_list vargs;
2380 struct device *dev;
2381
2382 va_start(vargs, fmt);
2383 dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
2384 va_end(vargs);
2385 return dev;
2386 }
2387 EXPORT_SYMBOL_GPL(device_create);
2388
2389 /**
2390 * device_create_with_groups - creates a device and registers it with sysfs
2391 * @class: pointer to the struct class that this device should be registered to
2392 * @parent: pointer to the parent struct device of this new device, if any
2393 * @devt: the dev_t for the char device to be added
2394 * @drvdata: the data to be added to the device for callbacks
2395 * @groups: NULL-terminated list of attribute groups to be created
2396 * @fmt: string for the device's name
2397 *
2398 * This function can be used by char device classes. A struct device
2399 * will be created in sysfs, registered to the specified class.
2400 * Additional attributes specified in the groups parameter will also
2401 * be created automatically.
2402 *
2403 * A "dev" file will be created, showing the dev_t for the device, if
2404 * the dev_t is not 0,0.
2405 * If a pointer to a parent struct device is passed in, the newly created
2406 * struct device will be a child of that device in sysfs.
2407 * The pointer to the struct device will be returned from the call.
2408 * Any further sysfs files that might be required can be created using this
2409 * pointer.
2410 *
2411 * Returns &struct device pointer on success, or ERR_PTR() on error.
2412 *
2413 * Note: the struct class passed to this function must have previously
2414 * been created with a call to class_create().
2415 */
2416 struct device *device_create_with_groups(struct class *class,
2417 struct device *parent, dev_t devt,
2418 void *drvdata,
2419 const struct attribute_group **groups,
2420 const char *fmt, ...)
2421 {
2422 va_list vargs;
2423 struct device *dev;
2424
2425 va_start(vargs, fmt);
2426 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
2427 fmt, vargs);
2428 va_end(vargs);
2429 return dev;
2430 }
2431 EXPORT_SYMBOL_GPL(device_create_with_groups);
2432
2433 static int __match_devt(struct device *dev, const void *data)
2434 {
2435 const dev_t *devt = data;
2436
2437 return dev->devt == *devt;
2438 }
2439
2440 /**
2441 * device_destroy - removes a device that was created with device_create()
2442 * @class: pointer to the struct class that this device was registered with
2443 * @devt: the dev_t of the device that was previously registered
2444 *
2445 * This call unregisters and cleans up a device that was created with a
2446 * call to device_create().
2447 */
2448 void device_destroy(struct class *class, dev_t devt)
2449 {
2450 struct device *dev;
2451
2452 dev = class_find_device(class, NULL, &devt, __match_devt);
2453 if (dev) {
2454 put_device(dev);
2455 device_unregister(dev);
2456 }
2457 }
2458 EXPORT_SYMBOL_GPL(device_destroy);
2459
2460 /**
2461 * device_rename - renames a device
2462 * @dev: the pointer to the struct device to be renamed
2463 * @new_name: the new name of the device
2464 *
2465 * It is the responsibility of the caller to provide mutual
2466 * exclusion between two different calls of device_rename
2467 * on the same device to ensure that new_name is valid and
2468 * won't conflict with other devices.
2469 *
2470 * Note: Don't call this function. Currently, the networking layer calls this
2471 * function, but that will change. The following text from Kay Sievers offers
2472 * some insight:
2473 *
2474 * Renaming devices is racy at many levels, symlinks and other stuff are not
2475 * replaced atomically, and you get a "move" uevent, but it's not easy to
2476 * connect the event to the old and new device. Device nodes are not renamed at
2477 * all, there isn't even support for that in the kernel now.
2478 *
2479 * In the meantime, during renaming, your target name might be taken by another
2480 * driver, creating conflicts. Or the old name is taken directly after you
2481 * renamed it -- then you get events for the same DEVPATH, before you even see
2482 * the "move" event. It's just a mess, and nothing new should ever rely on
2483 * kernel device renaming. Besides that, it's not even implemented now for
2484 * other things than (driver-core wise very simple) network devices.
2485 *
2486 * We are currently about to change network renaming in udev to completely
2487 * disallow renaming of devices in the same namespace as the kernel uses,
2488 * because we can't solve the problems properly, that arise with swapping names
2489 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
2490 * be allowed to some other name than eth[0-9]*, for the aforementioned
2491 * reasons.
2492 *
2493 * Make up a "real" name in the driver before you register anything, or add
2494 * some other attributes for userspace to find the device, or use udev to add
2495 * symlinks -- but never rename kernel devices later, it's a complete mess. We
2496 * don't even want to get into that and try to implement the missing pieces in
2497 * the core. We really have other pieces to fix in the driver core mess. :)
2498 */
2499 int device_rename(struct device *dev, const char *new_name)
2500 {
2501 struct kobject *kobj = &dev->kobj;
2502 char *old_device_name = NULL;
2503 int error;
2504
2505 dev = get_device(dev);
2506 if (!dev)
2507 return -EINVAL;
2508
2509 dev_dbg(dev, "renaming to %s\n", new_name);
2510
2511 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
2512 if (!old_device_name) {
2513 error = -ENOMEM;
2514 goto out;
2515 }
2516
2517 if (dev->class) {
2518 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
2519 kobj, old_device_name,
2520 new_name, kobject_namespace(kobj));
2521 if (error)
2522 goto out;
2523 }
2524
2525 error = kobject_rename(kobj, new_name);
2526 if (error)
2527 goto out;
2528
2529 out:
2530 put_device(dev);
2531
2532 kfree(old_device_name);
2533
2534 return error;
2535 }
2536 EXPORT_SYMBOL_GPL(device_rename);
2537
2538 static int device_move_class_links(struct device *dev,
2539 struct device *old_parent,
2540 struct device *new_parent)
2541 {
2542 int error = 0;
2543
2544 if (old_parent)
2545 sysfs_remove_link(&dev->kobj, "device");
2546 if (new_parent)
2547 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
2548 "device");
2549 return error;
2550 }
2551
2552 /**
2553 * device_move - moves a device to a new parent
2554 * @dev: the pointer to the struct device to be moved
2555 * @new_parent: the new parent of the device (can by NULL)
2556 * @dpm_order: how to reorder the dpm_list
2557 */
2558 int device_move(struct device *dev, struct device *new_parent,
2559 enum dpm_order dpm_order)
2560 {
2561 int error;
2562 struct device *old_parent;
2563 struct kobject *new_parent_kobj;
2564
2565 dev = get_device(dev);
2566 if (!dev)
2567 return -EINVAL;
2568
2569 device_pm_lock();
2570 new_parent = get_device(new_parent);
2571 new_parent_kobj = get_device_parent(dev, new_parent);
2572
2573 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
2574 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
2575 error = kobject_move(&dev->kobj, new_parent_kobj);
2576 if (error) {
2577 cleanup_glue_dir(dev, new_parent_kobj);
2578 put_device(new_parent);
2579 goto out;
2580 }
2581 old_parent = dev->parent;
2582 dev->parent = new_parent;
2583 if (old_parent)
2584 klist_remove(&dev->p->knode_parent);
2585 if (new_parent) {
2586 klist_add_tail(&dev->p->knode_parent,
2587 &new_parent->p->klist_children);
2588 set_dev_node(dev, dev_to_node(new_parent));
2589 }
2590
2591 if (dev->class) {
2592 error = device_move_class_links(dev, old_parent, new_parent);
2593 if (error) {
2594 /* We ignore errors on cleanup since we're hosed anyway... */
2595 device_move_class_links(dev, new_parent, old_parent);
2596 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
2597 if (new_parent)
2598 klist_remove(&dev->p->knode_parent);
2599 dev->parent = old_parent;
2600 if (old_parent) {
2601 klist_add_tail(&dev->p->knode_parent,
2602 &old_parent->p->klist_children);
2603 set_dev_node(dev, dev_to_node(old_parent));
2604 }
2605 }
2606 cleanup_glue_dir(dev, new_parent_kobj);
2607 put_device(new_parent);
2608 goto out;
2609 }
2610 }
2611 switch (dpm_order) {
2612 case DPM_ORDER_NONE:
2613 break;
2614 case DPM_ORDER_DEV_AFTER_PARENT:
2615 device_pm_move_after(dev, new_parent);
2616 devices_kset_move_after(dev, new_parent);
2617 break;
2618 case DPM_ORDER_PARENT_BEFORE_DEV:
2619 device_pm_move_before(new_parent, dev);
2620 devices_kset_move_before(new_parent, dev);
2621 break;
2622 case DPM_ORDER_DEV_LAST:
2623 device_pm_move_last(dev);
2624 devices_kset_move_last(dev);
2625 break;
2626 }
2627
2628 put_device(old_parent);
2629 out:
2630 device_pm_unlock();
2631 put_device(dev);
2632 return error;
2633 }
2634 EXPORT_SYMBOL_GPL(device_move);
2635
2636 /**
2637 * device_shutdown - call ->shutdown() on each device to shutdown.
2638 */
2639 void device_shutdown(void)
2640 {
2641 struct device *dev, *parent;
2642
2643 spin_lock(&devices_kset->list_lock);
2644 /*
2645 * Walk the devices list backward, shutting down each in turn.
2646 * Beware that device unplug events may also start pulling
2647 * devices offline, even as the system is shutting down.
2648 */
2649 while (!list_empty(&devices_kset->list)) {
2650 dev = list_entry(devices_kset->list.prev, struct device,
2651 kobj.entry);
2652
2653 /*
2654 * hold reference count of device's parent to
2655 * prevent it from being freed because parent's
2656 * lock is to be held
2657 */
2658 parent = get_device(dev->parent);
2659 get_device(dev);
2660 /*
2661 * Make sure the device is off the kset list, in the
2662 * event that dev->*->shutdown() doesn't remove it.
2663 */
2664 list_del_init(&dev->kobj.entry);
2665 spin_unlock(&devices_kset->list_lock);
2666
2667 /* hold lock to avoid race with probe/release */
2668 if (parent)
2669 device_lock(parent);
2670 device_lock(dev);
2671
2672 /* Don't allow any more runtime suspends */
2673 pm_runtime_get_noresume(dev);
2674 pm_runtime_barrier(dev);
2675
2676 if (dev->bus && dev->bus->shutdown) {
2677 if (initcall_debug)
2678 dev_info(dev, "shutdown\n");
2679 dev->bus->shutdown(dev);
2680 } else if (dev->driver && dev->driver->shutdown) {
2681 if (initcall_debug)
2682 dev_info(dev, "shutdown\n");
2683 dev->driver->shutdown(dev);
2684 }
2685
2686 device_unlock(dev);
2687 if (parent)
2688 device_unlock(parent);
2689
2690 put_device(dev);
2691 put_device(parent);
2692
2693 spin_lock(&devices_kset->list_lock);
2694 }
2695 spin_unlock(&devices_kset->list_lock);
2696 }
2697
2698 /*
2699 * Device logging functions
2700 */
2701
2702 #ifdef CONFIG_PRINTK
2703 static int
2704 create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen)
2705 {
2706 const char *subsys;
2707 size_t pos = 0;
2708
2709 if (dev->class)
2710 subsys = dev->class->name;
2711 else if (dev->bus)
2712 subsys = dev->bus->name;
2713 else
2714 return 0;
2715
2716 pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
2717 if (pos >= hdrlen)
2718 goto overflow;
2719
2720 /*
2721 * Add device identifier DEVICE=:
2722 * b12:8 block dev_t
2723 * c127:3 char dev_t
2724 * n8 netdev ifindex
2725 * +sound:card0 subsystem:devname
2726 */
2727 if (MAJOR(dev->devt)) {
2728 char c;
2729
2730 if (strcmp(subsys, "block") == 0)
2731 c = 'b';
2732 else
2733 c = 'c';
2734 pos++;
2735 pos += snprintf(hdr + pos, hdrlen - pos,
2736 "DEVICE=%c%u:%u",
2737 c, MAJOR(dev->devt), MINOR(dev->devt));
2738 } else if (strcmp(subsys, "net") == 0) {
2739 struct net_device *net = to_net_dev(dev);
2740
2741 pos++;
2742 pos += snprintf(hdr + pos, hdrlen - pos,
2743 "DEVICE=n%u", net->ifindex);
2744 } else {
2745 pos++;
2746 pos += snprintf(hdr + pos, hdrlen - pos,
2747 "DEVICE=+%s:%s", subsys, dev_name(dev));
2748 }
2749
2750 if (pos >= hdrlen)
2751 goto overflow;
2752
2753 return pos;
2754
2755 overflow:
2756 dev_WARN(dev, "device/subsystem name too long");
2757 return 0;
2758 }
2759
2760 int dev_vprintk_emit(int level, const struct device *dev,
2761 const char *fmt, va_list args)
2762 {
2763 char hdr[128];
2764 size_t hdrlen;
2765
2766 hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
2767
2768 return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
2769 }
2770 EXPORT_SYMBOL(dev_vprintk_emit);
2771
2772 int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
2773 {
2774 va_list args;
2775 int r;
2776
2777 va_start(args, fmt);
2778
2779 r = dev_vprintk_emit(level, dev, fmt, args);
2780
2781 va_end(args);
2782
2783 return r;
2784 }
2785 EXPORT_SYMBOL(dev_printk_emit);
2786
2787 static void __dev_printk(const char *level, const struct device *dev,
2788 struct va_format *vaf)
2789 {
2790 if (dev)
2791 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
2792 dev_driver_string(dev), dev_name(dev), vaf);
2793 else
2794 printk("%s(NULL device *): %pV", level, vaf);
2795 }
2796
2797 void dev_printk(const char *level, const struct device *dev,
2798 const char *fmt, ...)
2799 {
2800 struct va_format vaf;
2801 va_list args;
2802
2803 va_start(args, fmt);
2804
2805 vaf.fmt = fmt;
2806 vaf.va = &args;
2807
2808 __dev_printk(level, dev, &vaf);
2809
2810 va_end(args);
2811 }
2812 EXPORT_SYMBOL(dev_printk);
2813
2814 #define define_dev_printk_level(func, kern_level) \
2815 void func(const struct device *dev, const char *fmt, ...) \
2816 { \
2817 struct va_format vaf; \
2818 va_list args; \
2819 \
2820 va_start(args, fmt); \
2821 \
2822 vaf.fmt = fmt; \
2823 vaf.va = &args; \
2824 \
2825 __dev_printk(kern_level, dev, &vaf); \
2826 \
2827 va_end(args); \
2828 } \
2829 EXPORT_SYMBOL(func);
2830
2831 define_dev_printk_level(dev_emerg, KERN_EMERG);
2832 define_dev_printk_level(dev_alert, KERN_ALERT);
2833 define_dev_printk_level(dev_crit, KERN_CRIT);
2834 define_dev_printk_level(dev_err, KERN_ERR);
2835 define_dev_printk_level(dev_warn, KERN_WARNING);
2836 define_dev_printk_level(dev_notice, KERN_NOTICE);
2837 define_dev_printk_level(_dev_info, KERN_INFO);
2838
2839 #endif
2840
2841 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
2842 {
2843 return fwnode && !IS_ERR(fwnode->secondary);
2844 }
2845
2846 /**
2847 * set_primary_fwnode - Change the primary firmware node of a given device.
2848 * @dev: Device to handle.
2849 * @fwnode: New primary firmware node of the device.
2850 *
2851 * Set the device's firmware node pointer to @fwnode, but if a secondary
2852 * firmware node of the device is present, preserve it.
2853 */
2854 void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
2855 {
2856 if (fwnode) {
2857 struct fwnode_handle *fn = dev->fwnode;
2858
2859 if (fwnode_is_primary(fn))
2860 fn = fn->secondary;
2861
2862 if (fn) {
2863 WARN_ON(fwnode->secondary);
2864 fwnode->secondary = fn;
2865 }
2866 dev->fwnode = fwnode;
2867 } else {
2868 dev->fwnode = fwnode_is_primary(dev->fwnode) ?
2869 dev->fwnode->secondary : NULL;
2870 }
2871 }
2872 EXPORT_SYMBOL_GPL(set_primary_fwnode);
2873
2874 /**
2875 * set_secondary_fwnode - Change the secondary firmware node of a given device.
2876 * @dev: Device to handle.
2877 * @fwnode: New secondary firmware node of the device.
2878 *
2879 * If a primary firmware node of the device is present, set its secondary
2880 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
2881 * @fwnode.
2882 */
2883 void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
2884 {
2885 if (fwnode)
2886 fwnode->secondary = ERR_PTR(-ENODEV);
2887
2888 if (fwnode_is_primary(dev->fwnode))
2889 dev->fwnode->secondary = fwnode;
2890 else
2891 dev->fwnode = fwnode;
2892 }