1 // SPDX-License-Identifier: GPL-2.0
3 * drivers/base/core.c - core driver model code (device registration, etc)
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.
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>
23 #include <linux/of_device.h>
24 #include <linux/genhd.h>
25 #include <linux/mutex.h>
26 #include <linux/pm_runtime.h>
27 #include <linux/netdevice.h>
28 #include <linux/sched/signal.h>
29 #include <linux/sysfs.h>
32 #include "power/power.h"
34 #ifdef CONFIG_SYSFS_DEPRECATED
35 #ifdef CONFIG_SYSFS_DEPRECATED_V2
36 long sysfs_deprecated = 1;
38 long sysfs_deprecated = 0;
40 static int __init sysfs_deprecated_setup(char *arg)
42 return kstrtol(arg, 10, &sysfs_deprecated);
44 early_param("sysfs.deprecated", sysfs_deprecated_setup);
47 /* Device links support. */
48 static LIST_HEAD(wait_for_suppliers);
49 static DEFINE_MUTEX(wfs_lock);
50 static LIST_HEAD(deferred_sync);
51 static unsigned int defer_sync_state_count = 1;
52 static unsigned int defer_fw_devlink_count;
53 static LIST_HEAD(deferred_fw_devlink);
54 static DEFINE_MUTEX(defer_fw_devlink_lock);
55 static bool fw_devlink_is_permissive(void);
58 static DEFINE_MUTEX(device_links_lock);
59 DEFINE_STATIC_SRCU(device_links_srcu);
61 static inline void device_links_write_lock(void)
63 mutex_lock(&device_links_lock);
66 static inline void device_links_write_unlock(void)
68 mutex_unlock(&device_links_lock);
71 int device_links_read_lock(void) __acquires(&device_links_srcu)
73 return srcu_read_lock(&device_links_srcu);
76 void device_links_read_unlock(int idx) __releases(&device_links_srcu)
78 srcu_read_unlock(&device_links_srcu, idx);
81 int device_links_read_lock_held(void)
83 return srcu_read_lock_held(&device_links_srcu);
85 #else /* !CONFIG_SRCU */
86 static DECLARE_RWSEM(device_links_lock);
88 static inline void device_links_write_lock(void)
90 down_write(&device_links_lock);
93 static inline void device_links_write_unlock(void)
95 up_write(&device_links_lock);
98 int device_links_read_lock(void)
100 down_read(&device_links_lock);
104 void device_links_read_unlock(int not_used)
106 up_read(&device_links_lock);
109 #ifdef CONFIG_DEBUG_LOCK_ALLOC
110 int device_links_read_lock_held(void)
112 return lockdep_is_held(&device_links_lock);
115 #endif /* !CONFIG_SRCU */
118 * device_is_dependent - Check if one device depends on another one
119 * @dev: Device to check dependencies for.
120 * @target: Device to check against.
122 * Check if @target depends on @dev or any device dependent on it (its child or
123 * its consumer etc). Return 1 if that is the case or 0 otherwise.
125 int device_is_dependent(struct device *dev, void *target)
127 struct device_link *link;
133 ret = device_for_each_child(dev, target, device_is_dependent);
137 list_for_each_entry(link, &dev->links.consumers, s_node) {
138 if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
141 if (link->consumer == target)
144 ret = device_is_dependent(link->consumer, target);
151 static void device_link_init_status(struct device_link *link,
152 struct device *consumer,
153 struct device *supplier)
155 switch (supplier->links.status) {
157 switch (consumer->links.status) {
160 * A consumer driver can create a link to a supplier
161 * that has not completed its probing yet as long as it
162 * knows that the supplier is already functional (for
163 * example, it has just acquired some resources from the
166 link->status = DL_STATE_CONSUMER_PROBE;
169 link->status = DL_STATE_DORMANT;
173 case DL_DEV_DRIVER_BOUND:
174 switch (consumer->links.status) {
176 link->status = DL_STATE_CONSUMER_PROBE;
178 case DL_DEV_DRIVER_BOUND:
179 link->status = DL_STATE_ACTIVE;
182 link->status = DL_STATE_AVAILABLE;
186 case DL_DEV_UNBINDING:
187 link->status = DL_STATE_SUPPLIER_UNBIND;
190 link->status = DL_STATE_DORMANT;
195 static int device_reorder_to_tail(struct device *dev, void *not_used)
197 struct device_link *link;
200 * Devices that have not been registered yet will be put to the ends
201 * of the lists during the registration, so skip them here.
203 if (device_is_registered(dev))
204 devices_kset_move_last(dev);
206 if (device_pm_initialized(dev))
207 device_pm_move_last(dev);
209 device_for_each_child(dev, NULL, device_reorder_to_tail);
210 list_for_each_entry(link, &dev->links.consumers, s_node) {
211 if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
213 device_reorder_to_tail(link->consumer, NULL);
220 * device_pm_move_to_tail - Move set of devices to the end of device lists
221 * @dev: Device to move
223 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
225 * It moves the @dev along with all of its children and all of its consumers
226 * to the ends of the device_kset and dpm_list, recursively.
228 void device_pm_move_to_tail(struct device *dev)
232 idx = device_links_read_lock();
234 device_reorder_to_tail(dev, NULL);
236 device_links_read_unlock(idx);
239 #define to_devlink(dev) container_of((dev), struct device_link, link_dev)
241 static ssize_t status_show(struct device *dev,
242 struct device_attribute *attr, char *buf)
246 switch (to_devlink(dev)->status) {
248 status = "not tracked"; break;
249 case DL_STATE_DORMANT:
250 status = "dormant"; break;
251 case DL_STATE_AVAILABLE:
252 status = "available"; break;
253 case DL_STATE_CONSUMER_PROBE:
254 status = "consumer probing"; break;
255 case DL_STATE_ACTIVE:
256 status = "active"; break;
257 case DL_STATE_SUPPLIER_UNBIND:
258 status = "supplier unbinding"; break;
260 status = "unknown"; break;
262 return sprintf(buf, "%s\n", status);
264 static DEVICE_ATTR_RO(status);
266 static ssize_t auto_remove_on_show(struct device *dev,
267 struct device_attribute *attr, char *buf)
269 struct device_link *link = to_devlink(dev);
272 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
273 str = "supplier unbind";
274 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
275 str = "consumer unbind";
279 return sprintf(buf, "%s\n", str);
281 static DEVICE_ATTR_RO(auto_remove_on);
283 static ssize_t runtime_pm_show(struct device *dev,
284 struct device_attribute *attr, char *buf)
286 struct device_link *link = to_devlink(dev);
288 return sprintf(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
290 static DEVICE_ATTR_RO(runtime_pm);
292 static ssize_t sync_state_only_show(struct device *dev,
293 struct device_attribute *attr, char *buf)
295 struct device_link *link = to_devlink(dev);
297 return sprintf(buf, "%d\n", !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
299 static DEVICE_ATTR_RO(sync_state_only);
301 static struct attribute *devlink_attrs[] = {
302 &dev_attr_status.attr,
303 &dev_attr_auto_remove_on.attr,
304 &dev_attr_runtime_pm.attr,
305 &dev_attr_sync_state_only.attr,
308 ATTRIBUTE_GROUPS(devlink);
310 static void device_link_free(struct device_link *link)
312 while (refcount_dec_not_one(&link->rpm_active))
313 pm_runtime_put(link->supplier);
315 put_device(link->consumer);
316 put_device(link->supplier);
321 static void __device_link_free_srcu(struct rcu_head *rhead)
323 device_link_free(container_of(rhead, struct device_link, rcu_head));
326 static void devlink_dev_release(struct device *dev)
328 struct device_link *link = to_devlink(dev);
330 call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
333 static void devlink_dev_release(struct device *dev)
335 device_link_free(to_devlink(dev));
339 static struct class devlink_class = {
341 .owner = THIS_MODULE,
342 .dev_groups = devlink_groups,
343 .dev_release = devlink_dev_release,
346 static int devlink_add_symlinks(struct device *dev,
347 struct class_interface *class_intf)
351 struct device_link *link = to_devlink(dev);
352 struct device *sup = link->supplier;
353 struct device *con = link->consumer;
356 len = max(strlen(dev_name(sup)), strlen(dev_name(con)));
357 len += strlen("supplier:") + 1;
358 buf = kzalloc(len, GFP_KERNEL);
362 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
366 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
370 snprintf(buf, len, "consumer:%s", dev_name(con));
371 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
375 snprintf(buf, len, "supplier:%s", dev_name(sup));
376 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
383 snprintf(buf, len, "consumer:%s", dev_name(con));
384 sysfs_remove_link(&sup->kobj, buf);
386 sysfs_remove_link(&link->link_dev.kobj, "consumer");
388 sysfs_remove_link(&link->link_dev.kobj, "supplier");
394 static void devlink_remove_symlinks(struct device *dev,
395 struct class_interface *class_intf)
397 struct device_link *link = to_devlink(dev);
399 struct device *sup = link->supplier;
400 struct device *con = link->consumer;
403 sysfs_remove_link(&link->link_dev.kobj, "consumer");
404 sysfs_remove_link(&link->link_dev.kobj, "supplier");
406 len = max(strlen(dev_name(sup)), strlen(dev_name(con)));
407 len += strlen("supplier:") + 1;
408 buf = kzalloc(len, GFP_KERNEL);
410 WARN(1, "Unable to properly free device link symlinks!\n");
414 snprintf(buf, len, "supplier:%s", dev_name(sup));
415 sysfs_remove_link(&con->kobj, buf);
416 snprintf(buf, len, "consumer:%s", dev_name(con));
417 sysfs_remove_link(&sup->kobj, buf);
421 static struct class_interface devlink_class_intf = {
422 .class = &devlink_class,
423 .add_dev = devlink_add_symlinks,
424 .remove_dev = devlink_remove_symlinks,
427 static int __init devlink_class_init(void)
431 ret = class_register(&devlink_class);
435 ret = class_interface_register(&devlink_class_intf);
437 class_unregister(&devlink_class);
441 postcore_initcall(devlink_class_init);
443 #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
444 DL_FLAG_AUTOREMOVE_SUPPLIER | \
445 DL_FLAG_AUTOPROBE_CONSUMER | \
446 DL_FLAG_SYNC_STATE_ONLY)
448 #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
449 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
452 * device_link_add - Create a link between two devices.
453 * @consumer: Consumer end of the link.
454 * @supplier: Supplier end of the link.
455 * @flags: Link flags.
457 * The caller is responsible for the proper synchronization of the link creation
458 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
459 * runtime PM framework to take the link into account. Second, if the
460 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
461 * be forced into the active metastate and reference-counted upon the creation
462 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
465 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
466 * expected to release the link returned by it directly with the help of either
467 * device_link_del() or device_link_remove().
469 * If that flag is not set, however, the caller of this function is handing the
470 * management of the link over to the driver core entirely and its return value
471 * can only be used to check whether or not the link is present. In that case,
472 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
473 * flags can be used to indicate to the driver core when the link can be safely
474 * deleted. Namely, setting one of them in @flags indicates to the driver core
475 * that the link is not going to be used (by the given caller of this function)
476 * after unbinding the consumer or supplier driver, respectively, from its
477 * device, so the link can be deleted at that point. If none of them is set,
478 * the link will be maintained until one of the devices pointed to by it (either
479 * the consumer or the supplier) is unregistered.
481 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
482 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
483 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
484 * be used to request the driver core to automaticall probe for a consmer
485 * driver after successfully binding a driver to the supplier device.
487 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
488 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
489 * the same time is invalid and will cause NULL to be returned upfront.
490 * However, if a device link between the given @consumer and @supplier pair
491 * exists already when this function is called for them, the existing link will
492 * be returned regardless of its current type and status (the link's flags may
493 * be modified then). The caller of this function is then expected to treat
494 * the link as though it has just been created, so (in particular) if
495 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
496 * explicitly when not needed any more (as stated above).
498 * A side effect of the link creation is re-ordering of dpm_list and the
499 * devices_kset list by moving the consumer device and all devices depending
500 * on it to the ends of these lists (that does not happen to devices that have
501 * not been registered when this function is called).
503 * The supplier device is required to be registered when this function is called
504 * and NULL will be returned if that is not the case. The consumer device need
505 * not be registered, however.
507 struct device_link *device_link_add(struct device *consumer,
508 struct device *supplier, u32 flags)
510 struct device_link *link;
512 if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS ||
513 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
514 (flags & DL_FLAG_SYNC_STATE_ONLY &&
515 flags != DL_FLAG_SYNC_STATE_ONLY) ||
516 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
517 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
518 DL_FLAG_AUTOREMOVE_SUPPLIER)))
521 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
522 if (pm_runtime_get_sync(supplier) < 0) {
523 pm_runtime_put_noidle(supplier);
528 if (!(flags & DL_FLAG_STATELESS))
529 flags |= DL_FLAG_MANAGED;
531 device_links_write_lock();
535 * If the supplier has not been fully registered yet or there is a
536 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
537 * the supplier already in the graph, return NULL. If the link is a
538 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
539 * because it only affects sync_state() callbacks.
541 if (!device_pm_initialized(supplier)
542 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
543 device_is_dependent(consumer, supplier))) {
549 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
550 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
551 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
553 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
554 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
556 list_for_each_entry(link, &supplier->links.consumers, s_node) {
557 if (link->consumer != consumer)
560 if (flags & DL_FLAG_PM_RUNTIME) {
561 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
562 pm_runtime_new_link(consumer);
563 link->flags |= DL_FLAG_PM_RUNTIME;
565 if (flags & DL_FLAG_RPM_ACTIVE)
566 refcount_inc(&link->rpm_active);
569 if (flags & DL_FLAG_STATELESS) {
570 kref_get(&link->kref);
571 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
572 !(link->flags & DL_FLAG_STATELESS)) {
573 link->flags |= DL_FLAG_STATELESS;
576 link->flags |= DL_FLAG_STATELESS;
582 * If the life time of the link following from the new flags is
583 * longer than indicated by the flags of the existing link,
584 * update the existing link to stay around longer.
586 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
587 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
588 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
589 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
591 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
592 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
593 DL_FLAG_AUTOREMOVE_SUPPLIER);
595 if (!(link->flags & DL_FLAG_MANAGED)) {
596 kref_get(&link->kref);
597 link->flags |= DL_FLAG_MANAGED;
598 device_link_init_status(link, consumer, supplier);
600 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
601 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
602 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
609 link = kzalloc(sizeof(*link), GFP_KERNEL);
613 refcount_set(&link->rpm_active, 1);
615 get_device(supplier);
616 link->supplier = supplier;
617 INIT_LIST_HEAD(&link->s_node);
618 get_device(consumer);
619 link->consumer = consumer;
620 INIT_LIST_HEAD(&link->c_node);
622 kref_init(&link->kref);
624 link->link_dev.class = &devlink_class;
625 device_set_pm_not_required(&link->link_dev);
626 dev_set_name(&link->link_dev, "%s--%s",
627 dev_name(supplier), dev_name(consumer));
628 if (device_register(&link->link_dev)) {
629 put_device(consumer);
630 put_device(supplier);
636 if (flags & DL_FLAG_PM_RUNTIME) {
637 if (flags & DL_FLAG_RPM_ACTIVE)
638 refcount_inc(&link->rpm_active);
640 pm_runtime_new_link(consumer);
643 /* Determine the initial link state. */
644 if (flags & DL_FLAG_STATELESS)
645 link->status = DL_STATE_NONE;
647 device_link_init_status(link, consumer, supplier);
650 * Some callers expect the link creation during consumer driver probe to
651 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
653 if (link->status == DL_STATE_CONSUMER_PROBE &&
654 flags & DL_FLAG_PM_RUNTIME)
655 pm_runtime_resume(supplier);
657 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
658 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
660 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
662 "Linked as a sync state only consumer to %s\n",
669 * Move the consumer and all of the devices depending on it to the end
670 * of dpm_list and the devices_kset list.
672 * It is necessary to hold dpm_list locked throughout all that or else
673 * we may end up suspending with a wrong ordering of it.
675 device_reorder_to_tail(consumer, NULL);
677 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
681 device_links_write_unlock();
683 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
684 pm_runtime_put(supplier);
688 EXPORT_SYMBOL_GPL(device_link_add);
691 * device_link_wait_for_supplier - Add device to wait_for_suppliers list
692 * @consumer: Consumer device
694 * Marks the @consumer device as waiting for suppliers to become available by
695 * adding it to the wait_for_suppliers list. The consumer device will never be
696 * probed until it's removed from the wait_for_suppliers list.
698 * The caller is responsible for adding the links to the supplier devices once
699 * they are available and removing the @consumer device from the
700 * wait_for_suppliers list once links to all the suppliers have been created.
702 * This function is NOT meant to be called from the probe function of the
703 * consumer but rather from code that creates/adds the consumer device.
705 static void device_link_wait_for_supplier(struct device *consumer,
708 mutex_lock(&wfs_lock);
709 list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers);
710 consumer->links.need_for_probe = need_for_probe;
711 mutex_unlock(&wfs_lock);
714 static void device_link_wait_for_mandatory_supplier(struct device *consumer)
716 device_link_wait_for_supplier(consumer, true);
719 static void device_link_wait_for_optional_supplier(struct device *consumer)
721 device_link_wait_for_supplier(consumer, false);
725 * device_link_add_missing_supplier_links - Add links from consumer devices to
726 * supplier devices, leaving any
727 * consumer with inactive suppliers on
728 * the wait_for_suppliers list
730 * Loops through all consumers waiting on suppliers and tries to add all their
731 * supplier links. If that succeeds, the consumer device is removed from
732 * wait_for_suppliers list. Otherwise, they are left in the wait_for_suppliers
733 * list. Devices left on the wait_for_suppliers list will not be probed.
735 * The fwnode add_links callback is expected to return 0 if it has found and
736 * added all the supplier links for the consumer device. It should return an
737 * error if it isn't able to do so.
739 * The caller of device_link_wait_for_supplier() is expected to call this once
740 * it's aware of potential suppliers becoming available.
742 static void device_link_add_missing_supplier_links(void)
744 struct device *dev, *tmp;
746 mutex_lock(&wfs_lock);
747 list_for_each_entry_safe(dev, tmp, &wait_for_suppliers,
748 links.needs_suppliers) {
749 int ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
751 list_del_init(&dev->links.needs_suppliers);
752 else if (ret != -ENODEV || fw_devlink_is_permissive())
753 dev->links.need_for_probe = false;
755 mutex_unlock(&wfs_lock);
759 static void __device_link_del(struct kref *kref)
761 struct device_link *link = container_of(kref, struct device_link, kref);
763 dev_dbg(link->consumer, "Dropping the link to %s\n",
764 dev_name(link->supplier));
766 if (link->flags & DL_FLAG_PM_RUNTIME)
767 pm_runtime_drop_link(link->consumer);
769 list_del_rcu(&link->s_node);
770 list_del_rcu(&link->c_node);
771 device_unregister(&link->link_dev);
773 #else /* !CONFIG_SRCU */
774 static void __device_link_del(struct kref *kref)
776 struct device_link *link = container_of(kref, struct device_link, kref);
778 dev_info(link->consumer, "Dropping the link to %s\n",
779 dev_name(link->supplier));
781 if (link->flags & DL_FLAG_PM_RUNTIME)
782 pm_runtime_drop_link(link->consumer);
784 list_del(&link->s_node);
785 list_del(&link->c_node);
786 device_unregister(&link->link_dev);
788 #endif /* !CONFIG_SRCU */
790 static void device_link_put_kref(struct device_link *link)
792 if (link->flags & DL_FLAG_STATELESS)
793 kref_put(&link->kref, __device_link_del);
795 WARN(1, "Unable to drop a managed device link reference\n");
799 * device_link_del - Delete a stateless link between two devices.
800 * @link: Device link to delete.
802 * The caller must ensure proper synchronization of this function with runtime
803 * PM. If the link was added multiple times, it needs to be deleted as often.
804 * Care is required for hotplugged devices: Their links are purged on removal
805 * and calling device_link_del() is then no longer allowed.
807 void device_link_del(struct device_link *link)
809 device_links_write_lock();
810 device_link_put_kref(link);
811 device_links_write_unlock();
813 EXPORT_SYMBOL_GPL(device_link_del);
816 * device_link_remove - Delete a stateless link between two devices.
817 * @consumer: Consumer end of the link.
818 * @supplier: Supplier end of the link.
820 * The caller must ensure proper synchronization of this function with runtime
823 void device_link_remove(void *consumer, struct device *supplier)
825 struct device_link *link;
827 if (WARN_ON(consumer == supplier))
830 device_links_write_lock();
832 list_for_each_entry(link, &supplier->links.consumers, s_node) {
833 if (link->consumer == consumer) {
834 device_link_put_kref(link);
839 device_links_write_unlock();
841 EXPORT_SYMBOL_GPL(device_link_remove);
843 static void device_links_missing_supplier(struct device *dev)
845 struct device_link *link;
847 list_for_each_entry(link, &dev->links.suppliers, c_node) {
848 if (link->status != DL_STATE_CONSUMER_PROBE)
851 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
852 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
854 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
855 WRITE_ONCE(link->status, DL_STATE_DORMANT);
861 * device_links_check_suppliers - Check presence of supplier drivers.
862 * @dev: Consumer device.
864 * Check links from this device to any suppliers. Walk the list of the device's
865 * links to suppliers and see if all of them are available. If not, simply
866 * return -EPROBE_DEFER.
868 * We need to guarantee that the supplier will not go away after the check has
869 * been positive here. It only can go away in __device_release_driver() and
870 * that function checks the device's links to consumers. This means we need to
871 * mark the link as "consumer probe in progress" to make the supplier removal
872 * wait for us to complete (or bad things may happen).
874 * Links without the DL_FLAG_MANAGED flag set are ignored.
876 int device_links_check_suppliers(struct device *dev)
878 struct device_link *link;
882 * Device waiting for supplier to become available is not allowed to
885 mutex_lock(&wfs_lock);
886 if (!list_empty(&dev->links.needs_suppliers) &&
887 dev->links.need_for_probe) {
888 mutex_unlock(&wfs_lock);
889 return -EPROBE_DEFER;
891 mutex_unlock(&wfs_lock);
893 device_links_write_lock();
895 list_for_each_entry(link, &dev->links.suppliers, c_node) {
896 if (!(link->flags & DL_FLAG_MANAGED))
899 if (link->status != DL_STATE_AVAILABLE &&
900 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
901 device_links_missing_supplier(dev);
905 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
907 dev->links.status = DL_DEV_PROBING;
909 device_links_write_unlock();
914 * __device_links_queue_sync_state - Queue a device for sync_state() callback
915 * @dev: Device to call sync_state() on
916 * @list: List head to queue the @dev on
918 * Queues a device for a sync_state() callback when the device links write lock
919 * isn't held. This allows the sync_state() execution flow to use device links
920 * APIs. The caller must ensure this function is called with
921 * device_links_write_lock() held.
923 * This function does a get_device() to make sure the device is not freed while
926 * So the caller must also ensure that device_links_flush_sync_list() is called
927 * as soon as the caller releases device_links_write_lock(). This is necessary
928 * to make sure the sync_state() is called in a timely fashion and the
929 * put_device() is called on this device.
931 static void __device_links_queue_sync_state(struct device *dev,
932 struct list_head *list)
934 struct device_link *link;
936 if (!dev_has_sync_state(dev))
938 if (dev->state_synced)
941 list_for_each_entry(link, &dev->links.consumers, s_node) {
942 if (!(link->flags & DL_FLAG_MANAGED))
944 if (link->status != DL_STATE_ACTIVE)
949 * Set the flag here to avoid adding the same device to a list more
950 * than once. This can happen if new consumers get added to the device
951 * and probed before the list is flushed.
953 dev->state_synced = true;
955 if (WARN_ON(!list_empty(&dev->links.defer_hook)))
959 list_add_tail(&dev->links.defer_hook, list);
963 * device_links_flush_sync_list - Call sync_state() on a list of devices
964 * @list: List of devices to call sync_state() on
965 * @dont_lock_dev: Device for which lock is already held by the caller
967 * Calls sync_state() on all the devices that have been queued for it. This
968 * function is used in conjunction with __device_links_queue_sync_state(). The
969 * @dont_lock_dev parameter is useful when this function is called from a
970 * context where a device lock is already held.
972 static void device_links_flush_sync_list(struct list_head *list,
973 struct device *dont_lock_dev)
975 struct device *dev, *tmp;
977 list_for_each_entry_safe(dev, tmp, list, links.defer_hook) {
978 list_del_init(&dev->links.defer_hook);
980 if (dev != dont_lock_dev)
983 if (dev->bus->sync_state)
984 dev->bus->sync_state(dev);
985 else if (dev->driver && dev->driver->sync_state)
986 dev->driver->sync_state(dev);
988 if (dev != dont_lock_dev)
995 void device_links_supplier_sync_state_pause(void)
997 device_links_write_lock();
998 defer_sync_state_count++;
999 device_links_write_unlock();
1002 void device_links_supplier_sync_state_resume(void)
1004 struct device *dev, *tmp;
1005 LIST_HEAD(sync_list);
1007 device_links_write_lock();
1008 if (!defer_sync_state_count) {
1009 WARN(true, "Unmatched sync_state pause/resume!");
1012 defer_sync_state_count--;
1013 if (defer_sync_state_count)
1016 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_hook) {
1018 * Delete from deferred_sync list before queuing it to
1019 * sync_list because defer_hook is used for both lists.
1021 list_del_init(&dev->links.defer_hook);
1022 __device_links_queue_sync_state(dev, &sync_list);
1025 device_links_write_unlock();
1027 device_links_flush_sync_list(&sync_list, NULL);
1030 static int sync_state_resume_initcall(void)
1032 device_links_supplier_sync_state_resume();
1035 late_initcall(sync_state_resume_initcall);
1037 static void __device_links_supplier_defer_sync(struct device *sup)
1039 if (list_empty(&sup->links.defer_hook) && dev_has_sync_state(sup))
1040 list_add_tail(&sup->links.defer_hook, &deferred_sync);
1043 static void device_link_drop_managed(struct device_link *link)
1045 link->flags &= ~DL_FLAG_MANAGED;
1046 WRITE_ONCE(link->status, DL_STATE_NONE);
1047 kref_put(&link->kref, __device_link_del);
1050 static ssize_t waiting_for_supplier_show(struct device *dev,
1051 struct device_attribute *attr,
1057 mutex_lock(&wfs_lock);
1058 val = !list_empty(&dev->links.needs_suppliers)
1059 && dev->links.need_for_probe;
1060 mutex_unlock(&wfs_lock);
1062 return sprintf(buf, "%u\n", val);
1064 static DEVICE_ATTR_RO(waiting_for_supplier);
1067 * device_links_driver_bound - Update device links after probing its driver.
1068 * @dev: Device to update the links for.
1070 * The probe has been successful, so update links from this device to any
1071 * consumers by changing their status to "available".
1073 * Also change the status of @dev's links to suppliers to "active".
1075 * Links without the DL_FLAG_MANAGED flag set are ignored.
1077 void device_links_driver_bound(struct device *dev)
1079 struct device_link *link, *ln;
1080 LIST_HEAD(sync_list);
1083 * If a device probes successfully, it's expected to have created all
1084 * the device links it needs to or make new device links as it needs
1085 * them. So, it no longer needs to wait on any suppliers.
1087 mutex_lock(&wfs_lock);
1088 list_del_init(&dev->links.needs_suppliers);
1089 mutex_unlock(&wfs_lock);
1090 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1092 device_links_write_lock();
1094 list_for_each_entry(link, &dev->links.consumers, s_node) {
1095 if (!(link->flags & DL_FLAG_MANAGED))
1099 * Links created during consumer probe may be in the "consumer
1100 * probe" state to start with if the supplier is still probing
1101 * when they are created and they may become "active" if the
1102 * consumer probe returns first. Skip them here.
1104 if (link->status == DL_STATE_CONSUMER_PROBE ||
1105 link->status == DL_STATE_ACTIVE)
1108 WARN_ON(link->status != DL_STATE_DORMANT);
1109 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1111 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1112 driver_deferred_probe_add(link->consumer);
1115 if (defer_sync_state_count)
1116 __device_links_supplier_defer_sync(dev);
1118 __device_links_queue_sync_state(dev, &sync_list);
1120 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1121 struct device *supplier;
1123 if (!(link->flags & DL_FLAG_MANAGED))
1126 supplier = link->supplier;
1127 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1129 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1130 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1131 * save to drop the managed link completely.
1133 device_link_drop_managed(link);
1135 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1136 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1140 * This needs to be done even for the deleted
1141 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1142 * device link that was preventing the supplier from getting a
1143 * sync_state() call.
1145 if (defer_sync_state_count)
1146 __device_links_supplier_defer_sync(supplier);
1148 __device_links_queue_sync_state(supplier, &sync_list);
1151 dev->links.status = DL_DEV_DRIVER_BOUND;
1153 device_links_write_unlock();
1155 device_links_flush_sync_list(&sync_list, dev);
1159 * __device_links_no_driver - Update links of a device without a driver.
1160 * @dev: Device without a drvier.
1162 * Delete all non-persistent links from this device to any suppliers.
1164 * Persistent links stay around, but their status is changed to "available",
1165 * unless they already are in the "supplier unbind in progress" state in which
1166 * case they need not be updated.
1168 * Links without the DL_FLAG_MANAGED flag set are ignored.
1170 static void __device_links_no_driver(struct device *dev)
1172 struct device_link *link, *ln;
1174 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1175 if (!(link->flags & DL_FLAG_MANAGED))
1178 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1179 device_link_drop_managed(link);
1183 if (link->status != DL_STATE_CONSUMER_PROBE &&
1184 link->status != DL_STATE_ACTIVE)
1187 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1188 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1190 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1191 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1195 dev->links.status = DL_DEV_NO_DRIVER;
1199 * device_links_no_driver - Update links after failing driver probe.
1200 * @dev: Device whose driver has just failed to probe.
1202 * Clean up leftover links to consumers for @dev and invoke
1203 * %__device_links_no_driver() to update links to suppliers for it as
1206 * Links without the DL_FLAG_MANAGED flag set are ignored.
1208 void device_links_no_driver(struct device *dev)
1210 struct device_link *link;
1212 device_links_write_lock();
1214 list_for_each_entry(link, &dev->links.consumers, s_node) {
1215 if (!(link->flags & DL_FLAG_MANAGED))
1219 * The probe has failed, so if the status of the link is
1220 * "consumer probe" or "active", it must have been added by
1221 * a probing consumer while this device was still probing.
1222 * Change its state to "dormant", as it represents a valid
1223 * relationship, but it is not functionally meaningful.
1225 if (link->status == DL_STATE_CONSUMER_PROBE ||
1226 link->status == DL_STATE_ACTIVE)
1227 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1230 __device_links_no_driver(dev);
1232 device_links_write_unlock();
1236 * device_links_driver_cleanup - Update links after driver removal.
1237 * @dev: Device whose driver has just gone away.
1239 * Update links to consumers for @dev by changing their status to "dormant" and
1240 * invoke %__device_links_no_driver() to update links to suppliers for it as
1243 * Links without the DL_FLAG_MANAGED flag set are ignored.
1245 void device_links_driver_cleanup(struct device *dev)
1247 struct device_link *link, *ln;
1249 device_links_write_lock();
1251 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1252 if (!(link->flags & DL_FLAG_MANAGED))
1255 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1256 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1259 * autoremove the links between this @dev and its consumer
1260 * devices that are not active, i.e. where the link state
1261 * has moved to DL_STATE_SUPPLIER_UNBIND.
1263 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1264 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1265 device_link_drop_managed(link);
1267 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1270 list_del_init(&dev->links.defer_hook);
1271 __device_links_no_driver(dev);
1273 device_links_write_unlock();
1277 * device_links_busy - Check if there are any busy links to consumers.
1278 * @dev: Device to check.
1280 * Check each consumer of the device and return 'true' if its link's status
1281 * is one of "consumer probe" or "active" (meaning that the given consumer is
1282 * probing right now or its driver is present). Otherwise, change the link
1283 * state to "supplier unbind" to prevent the consumer from being probed
1284 * successfully going forward.
1286 * Return 'false' if there are no probing or active consumers.
1288 * Links without the DL_FLAG_MANAGED flag set are ignored.
1290 bool device_links_busy(struct device *dev)
1292 struct device_link *link;
1295 device_links_write_lock();
1297 list_for_each_entry(link, &dev->links.consumers, s_node) {
1298 if (!(link->flags & DL_FLAG_MANAGED))
1301 if (link->status == DL_STATE_CONSUMER_PROBE
1302 || link->status == DL_STATE_ACTIVE) {
1306 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1309 dev->links.status = DL_DEV_UNBINDING;
1311 device_links_write_unlock();
1316 * device_links_unbind_consumers - Force unbind consumers of the given device.
1317 * @dev: Device to unbind the consumers of.
1319 * Walk the list of links to consumers for @dev and if any of them is in the
1320 * "consumer probe" state, wait for all device probes in progress to complete
1323 * If that's not the case, change the status of the link to "supplier unbind"
1324 * and check if the link was in the "active" state. If so, force the consumer
1325 * driver to unbind and start over (the consumer will not re-probe as we have
1326 * changed the state of the link already).
1328 * Links without the DL_FLAG_MANAGED flag set are ignored.
1330 void device_links_unbind_consumers(struct device *dev)
1332 struct device_link *link;
1335 device_links_write_lock();
1337 list_for_each_entry(link, &dev->links.consumers, s_node) {
1338 enum device_link_state status;
1340 if (!(link->flags & DL_FLAG_MANAGED) ||
1341 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1344 status = link->status;
1345 if (status == DL_STATE_CONSUMER_PROBE) {
1346 device_links_write_unlock();
1348 wait_for_device_probe();
1351 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1352 if (status == DL_STATE_ACTIVE) {
1353 struct device *consumer = link->consumer;
1355 get_device(consumer);
1357 device_links_write_unlock();
1359 device_release_driver_internal(consumer, NULL,
1361 put_device(consumer);
1366 device_links_write_unlock();
1370 * device_links_purge - Delete existing links to other devices.
1371 * @dev: Target device.
1373 static void device_links_purge(struct device *dev)
1375 struct device_link *link, *ln;
1377 if (dev->class == &devlink_class)
1380 mutex_lock(&wfs_lock);
1381 list_del(&dev->links.needs_suppliers);
1382 mutex_unlock(&wfs_lock);
1385 * Delete all of the remaining links from this device to any other
1386 * devices (either consumers or suppliers).
1388 device_links_write_lock();
1390 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1391 WARN_ON(link->status == DL_STATE_ACTIVE);
1392 __device_link_del(&link->kref);
1395 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1396 WARN_ON(link->status != DL_STATE_DORMANT &&
1397 link->status != DL_STATE_NONE);
1398 __device_link_del(&link->kref);
1401 device_links_write_unlock();
1404 static u32 fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY;
1405 static int __init fw_devlink_setup(char *arg)
1410 if (strcmp(arg, "off") == 0) {
1411 fw_devlink_flags = 0;
1412 } else if (strcmp(arg, "permissive") == 0) {
1413 fw_devlink_flags = DL_FLAG_SYNC_STATE_ONLY;
1414 } else if (strcmp(arg, "on") == 0) {
1415 fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER;
1416 } else if (strcmp(arg, "rpm") == 0) {
1417 fw_devlink_flags = DL_FLAG_AUTOPROBE_CONSUMER |
1422 early_param("fw_devlink", fw_devlink_setup);
1424 u32 fw_devlink_get_flags(void)
1426 return fw_devlink_flags;
1429 static bool fw_devlink_is_permissive(void)
1431 return fw_devlink_flags == DL_FLAG_SYNC_STATE_ONLY;
1434 static void fw_devlink_link_device(struct device *dev)
1438 if (!fw_devlink_flags)
1441 mutex_lock(&defer_fw_devlink_lock);
1442 if (!defer_fw_devlink_count)
1443 device_link_add_missing_supplier_links();
1446 * The device's fwnode not having add_links() doesn't affect if other
1447 * consumers can find this device as a supplier. So, this check is
1448 * intentionally placed after device_link_add_missing_supplier_links().
1450 if (!fwnode_has_op(dev->fwnode, add_links))
1454 * If fw_devlink is being deferred, assume all devices have mandatory
1455 * suppliers they need to link to later. Then, when the fw_devlink is
1456 * resumed, all these devices will get a chance to try and link to any
1457 * suppliers they have.
1459 if (!defer_fw_devlink_count) {
1460 fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
1461 if (fw_ret == -ENODEV && fw_devlink_is_permissive())
1466 * defer_hook is not used to add device to deferred_sync list
1467 * until device is bound. Since deferred fw devlink also blocks
1468 * probing, same list hook can be used for deferred_fw_devlink.
1470 list_add_tail(&dev->links.defer_hook, &deferred_fw_devlink);
1473 if (fw_ret == -ENODEV)
1474 device_link_wait_for_mandatory_supplier(dev);
1476 device_link_wait_for_optional_supplier(dev);
1479 mutex_unlock(&defer_fw_devlink_lock);
1483 * fw_devlink_pause - Pause parsing of fwnode to create device links
1485 * Calling this function defers any fwnode parsing to create device links until
1486 * fw_devlink_resume() is called. Both these functions are ref counted and the
1487 * caller needs to match the calls.
1489 * While fw_devlink is paused:
1490 * - Any device that is added won't have its fwnode parsed to create device
1492 * - The probe of the device will also be deferred during this period.
1493 * - Any devices that were already added, but waiting for suppliers won't be
1494 * able to link to newly added devices.
1496 * Once fw_devlink_resume():
1497 * - All the fwnodes that was not parsed will be parsed.
1498 * - All the devices that were deferred probing will be reattempted if they
1499 * aren't waiting for any more suppliers.
1501 * This pair of functions, is mainly meant to optimize the parsing of fwnodes
1502 * when a lot of devices that need to link to each other are added in a short
1503 * interval of time. For example, adding all the top level devices in a system.
1505 * For example, if N devices are added and:
1506 * - All the consumers are added before their suppliers
1507 * - All the suppliers of the N devices are part of the N devices
1511 * - With the use of fw_devlink_pause() and fw_devlink_resume(), each device
1512 * will only need one parsing of its fwnode because it is guaranteed to find
1513 * all the supplier devices already registered and ready to link to. It won't
1514 * have to do another pass later to find one or more suppliers it couldn't
1515 * find in the first parse of the fwnode. So, we'll only need O(N) fwnode
1518 * - Without the use of fw_devlink_pause() and fw_devlink_resume(), we would
1519 * end up doing O(N^2) parses of fwnodes because every device that's added is
1520 * guaranteed to trigger a parse of the fwnode of every device added before
1521 * it. This O(N^2) parse is made worse by the fact that when a fwnode of a
1522 * device is parsed, all it descendant devices might need to have their
1523 * fwnodes parsed too (even if the devices themselves aren't added).
1525 void fw_devlink_pause(void)
1527 mutex_lock(&defer_fw_devlink_lock);
1528 defer_fw_devlink_count++;
1529 mutex_unlock(&defer_fw_devlink_lock);
1532 /** fw_devlink_resume - Resume parsing of fwnode to create device links
1534 * This function is used in conjunction with fw_devlink_pause() and is ref
1535 * counted. See documentation for fw_devlink_pause() for more details.
1537 void fw_devlink_resume(void)
1539 struct device *dev, *tmp;
1540 LIST_HEAD(probe_list);
1542 mutex_lock(&defer_fw_devlink_lock);
1543 if (!defer_fw_devlink_count) {
1544 WARN(true, "Unmatched fw_devlink pause/resume!");
1548 defer_fw_devlink_count--;
1549 if (defer_fw_devlink_count)
1552 device_link_add_missing_supplier_links();
1553 list_splice_tail_init(&deferred_fw_devlink, &probe_list);
1555 mutex_unlock(&defer_fw_devlink_lock);
1558 * bus_probe_device() can cause new devices to get added and they'll
1559 * try to grab defer_fw_devlink_lock. So, this needs to be done outside
1560 * the defer_fw_devlink_lock.
1562 list_for_each_entry_safe(dev, tmp, &probe_list, links.defer_hook) {
1563 list_del_init(&dev->links.defer_hook);
1564 bus_probe_device(dev);
1567 /* Device links support end. */
1569 int (*platform_notify)(struct device *dev) = NULL;
1570 int (*platform_notify_remove)(struct device *dev) = NULL;
1571 static struct kobject *dev_kobj;
1572 struct kobject *sysfs_dev_char_kobj;
1573 struct kobject *sysfs_dev_block_kobj;
1575 static DEFINE_MUTEX(device_hotplug_lock);
1577 void lock_device_hotplug(void)
1579 mutex_lock(&device_hotplug_lock);
1582 void unlock_device_hotplug(void)
1584 mutex_unlock(&device_hotplug_lock);
1587 int lock_device_hotplug_sysfs(void)
1589 if (mutex_trylock(&device_hotplug_lock))
1592 /* Avoid busy looping (5 ms of sleep should do). */
1594 return restart_syscall();
1598 static inline int device_is_not_partition(struct device *dev)
1600 return !(dev->type == &part_type);
1603 static inline int device_is_not_partition(struct device *dev)
1610 device_platform_notify(struct device *dev, enum kobject_action action)
1614 ret = acpi_platform_notify(dev, action);
1618 ret = software_node_notify(dev, action);
1622 if (platform_notify && action == KOBJ_ADD)
1623 platform_notify(dev);
1624 else if (platform_notify_remove && action == KOBJ_REMOVE)
1625 platform_notify_remove(dev);
1630 * dev_driver_string - Return a device's driver name, if at all possible
1631 * @dev: struct device to get the name of
1633 * Will return the device's driver's name if it is bound to a device. If
1634 * the device is not bound to a driver, it will return the name of the bus
1635 * it is attached to. If it is not attached to a bus either, an empty
1636 * string will be returned.
1638 const char *dev_driver_string(const struct device *dev)
1640 struct device_driver *drv;
1642 /* dev->driver can change to NULL underneath us because of unbinding,
1643 * so be careful about accessing it. dev->bus and dev->class should
1644 * never change once they are set, so they don't need special care.
1646 drv = READ_ONCE(dev->driver);
1647 return drv ? drv->name :
1648 (dev->bus ? dev->bus->name :
1649 (dev->class ? dev->class->name : ""));
1651 EXPORT_SYMBOL(dev_driver_string);
1653 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
1655 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
1658 struct device_attribute *dev_attr = to_dev_attr(attr);
1659 struct device *dev = kobj_to_dev(kobj);
1663 ret = dev_attr->show(dev, dev_attr, buf);
1664 if (ret >= (ssize_t)PAGE_SIZE) {
1665 printk("dev_attr_show: %pS returned bad count\n",
1671 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
1672 const char *buf, size_t count)
1674 struct device_attribute *dev_attr = to_dev_attr(attr);
1675 struct device *dev = kobj_to_dev(kobj);
1678 if (dev_attr->store)
1679 ret = dev_attr->store(dev, dev_attr, buf, count);
1683 static const struct sysfs_ops dev_sysfs_ops = {
1684 .show = dev_attr_show,
1685 .store = dev_attr_store,
1688 #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
1690 ssize_t device_store_ulong(struct device *dev,
1691 struct device_attribute *attr,
1692 const char *buf, size_t size)
1694 struct dev_ext_attribute *ea = to_ext_attr(attr);
1698 ret = kstrtoul(buf, 0, &new);
1701 *(unsigned long *)(ea->var) = new;
1702 /* Always return full write size even if we didn't consume all */
1705 EXPORT_SYMBOL_GPL(device_store_ulong);
1707 ssize_t device_show_ulong(struct device *dev,
1708 struct device_attribute *attr,
1711 struct dev_ext_attribute *ea = to_ext_attr(attr);
1712 return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
1714 EXPORT_SYMBOL_GPL(device_show_ulong);
1716 ssize_t device_store_int(struct device *dev,
1717 struct device_attribute *attr,
1718 const char *buf, size_t size)
1720 struct dev_ext_attribute *ea = to_ext_attr(attr);
1724 ret = kstrtol(buf, 0, &new);
1728 if (new > INT_MAX || new < INT_MIN)
1730 *(int *)(ea->var) = new;
1731 /* Always return full write size even if we didn't consume all */
1734 EXPORT_SYMBOL_GPL(device_store_int);
1736 ssize_t device_show_int(struct device *dev,
1737 struct device_attribute *attr,
1740 struct dev_ext_attribute *ea = to_ext_attr(attr);
1742 return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
1744 EXPORT_SYMBOL_GPL(device_show_int);
1746 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
1747 const char *buf, size_t size)
1749 struct dev_ext_attribute *ea = to_ext_attr(attr);
1751 if (strtobool(buf, ea->var) < 0)
1756 EXPORT_SYMBOL_GPL(device_store_bool);
1758 ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
1761 struct dev_ext_attribute *ea = to_ext_attr(attr);
1763 return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
1765 EXPORT_SYMBOL_GPL(device_show_bool);
1768 * device_release - free device structure.
1769 * @kobj: device's kobject.
1771 * This is called once the reference count for the object
1772 * reaches 0. We forward the call to the device's release
1773 * method, which should handle actually freeing the structure.
1775 static void device_release(struct kobject *kobj)
1777 struct device *dev = kobj_to_dev(kobj);
1778 struct device_private *p = dev->p;
1781 * Some platform devices are driven without driver attached
1782 * and managed resources may have been acquired. Make sure
1783 * all resources are released.
1785 * Drivers still can add resources into device after device
1786 * is deleted but alive, so release devres here to avoid
1787 * possible memory leak.
1789 devres_release_all(dev);
1793 else if (dev->type && dev->type->release)
1794 dev->type->release(dev);
1795 else if (dev->class && dev->class->dev_release)
1796 dev->class->dev_release(dev);
1798 WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n",
1803 static const void *device_namespace(struct kobject *kobj)
1805 struct device *dev = kobj_to_dev(kobj);
1806 const void *ns = NULL;
1808 if (dev->class && dev->class->ns_type)
1809 ns = dev->class->namespace(dev);
1814 static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
1816 struct device *dev = kobj_to_dev(kobj);
1818 if (dev->class && dev->class->get_ownership)
1819 dev->class->get_ownership(dev, uid, gid);
1822 static struct kobj_type device_ktype = {
1823 .release = device_release,
1824 .sysfs_ops = &dev_sysfs_ops,
1825 .namespace = device_namespace,
1826 .get_ownership = device_get_ownership,
1830 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
1832 struct kobj_type *ktype = get_ktype(kobj);
1834 if (ktype == &device_ktype) {
1835 struct device *dev = kobj_to_dev(kobj);
1844 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
1846 struct device *dev = kobj_to_dev(kobj);
1849 return dev->bus->name;
1851 return dev->class->name;
1855 static int dev_uevent(struct kset *kset, struct kobject *kobj,
1856 struct kobj_uevent_env *env)
1858 struct device *dev = kobj_to_dev(kobj);
1861 /* add device node properties if present */
1862 if (MAJOR(dev->devt)) {
1866 kuid_t uid = GLOBAL_ROOT_UID;
1867 kgid_t gid = GLOBAL_ROOT_GID;
1869 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
1870 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
1871 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
1873 add_uevent_var(env, "DEVNAME=%s", name);
1875 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
1876 if (!uid_eq(uid, GLOBAL_ROOT_UID))
1877 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
1878 if (!gid_eq(gid, GLOBAL_ROOT_GID))
1879 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
1884 if (dev->type && dev->type->name)
1885 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
1888 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
1890 /* Add common DT information about the device */
1891 of_device_uevent(dev, env);
1893 /* have the bus specific function add its stuff */
1894 if (dev->bus && dev->bus->uevent) {
1895 retval = dev->bus->uevent(dev, env);
1897 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
1898 dev_name(dev), __func__, retval);
1901 /* have the class specific function add its stuff */
1902 if (dev->class && dev->class->dev_uevent) {
1903 retval = dev->class->dev_uevent(dev, env);
1905 pr_debug("device: '%s': %s: class uevent() "
1906 "returned %d\n", dev_name(dev),
1910 /* have the device type specific function add its stuff */
1911 if (dev->type && dev->type->uevent) {
1912 retval = dev->type->uevent(dev, env);
1914 pr_debug("device: '%s': %s: dev_type uevent() "
1915 "returned %d\n", dev_name(dev),
1922 static const struct kset_uevent_ops device_uevent_ops = {
1923 .filter = dev_uevent_filter,
1924 .name = dev_uevent_name,
1925 .uevent = dev_uevent,
1928 static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
1931 struct kobject *top_kobj;
1933 struct kobj_uevent_env *env = NULL;
1938 /* search the kset, the device belongs to */
1939 top_kobj = &dev->kobj;
1940 while (!top_kobj->kset && top_kobj->parent)
1941 top_kobj = top_kobj->parent;
1942 if (!top_kobj->kset)
1945 kset = top_kobj->kset;
1946 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
1949 /* respect filter */
1950 if (kset->uevent_ops && kset->uevent_ops->filter)
1951 if (!kset->uevent_ops->filter(kset, &dev->kobj))
1954 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
1958 /* let the kset specific function add its keys */
1959 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
1963 /* copy keys to file */
1964 for (i = 0; i < env->envp_idx; i++)
1965 count += sprintf(&buf[count], "%s\n", env->envp[i]);
1971 static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
1972 const char *buf, size_t count)
1976 rc = kobject_synth_uevent(&dev->kobj, buf, count);
1979 dev_err(dev, "uevent: failed to send synthetic uevent\n");
1985 static DEVICE_ATTR_RW(uevent);
1987 static ssize_t online_show(struct device *dev, struct device_attribute *attr,
1993 val = !dev->offline;
1995 return sprintf(buf, "%u\n", val);
1998 static ssize_t online_store(struct device *dev, struct device_attribute *attr,
1999 const char *buf, size_t count)
2004 ret = strtobool(buf, &val);
2008 ret = lock_device_hotplug_sysfs();
2012 ret = val ? device_online(dev) : device_offline(dev);
2013 unlock_device_hotplug();
2014 return ret < 0 ? ret : count;
2016 static DEVICE_ATTR_RW(online);
2018 int device_add_groups(struct device *dev, const struct attribute_group **groups)
2020 return sysfs_create_groups(&dev->kobj, groups);
2022 EXPORT_SYMBOL_GPL(device_add_groups);
2024 void device_remove_groups(struct device *dev,
2025 const struct attribute_group **groups)
2027 sysfs_remove_groups(&dev->kobj, groups);
2029 EXPORT_SYMBOL_GPL(device_remove_groups);
2031 union device_attr_group_devres {
2032 const struct attribute_group *group;
2033 const struct attribute_group **groups;
2036 static int devm_attr_group_match(struct device *dev, void *res, void *data)
2038 return ((union device_attr_group_devres *)res)->group == data;
2041 static void devm_attr_group_remove(struct device *dev, void *res)
2043 union device_attr_group_devres *devres = res;
2044 const struct attribute_group *group = devres->group;
2046 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2047 sysfs_remove_group(&dev->kobj, group);
2050 static void devm_attr_groups_remove(struct device *dev, void *res)
2052 union device_attr_group_devres *devres = res;
2053 const struct attribute_group **groups = devres->groups;
2055 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2056 sysfs_remove_groups(&dev->kobj, groups);
2060 * devm_device_add_group - given a device, create a managed attribute group
2061 * @dev: The device to create the group for
2062 * @grp: The attribute group to create
2064 * This function creates a group for the first time. It will explicitly
2065 * warn and error if any of the attribute files being created already exist.
2067 * Returns 0 on success or error code on failure.
2069 int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2071 union device_attr_group_devres *devres;
2074 devres = devres_alloc(devm_attr_group_remove,
2075 sizeof(*devres), GFP_KERNEL);
2079 error = sysfs_create_group(&dev->kobj, grp);
2081 devres_free(devres);
2085 devres->group = grp;
2086 devres_add(dev, devres);
2089 EXPORT_SYMBOL_GPL(devm_device_add_group);
2092 * devm_device_remove_group: remove a managed group from a device
2093 * @dev: device to remove the group from
2094 * @grp: group to remove
2096 * This function removes a group of attributes from a device. The attributes
2097 * previously have to have been created for this group, otherwise it will fail.
2099 void devm_device_remove_group(struct device *dev,
2100 const struct attribute_group *grp)
2102 WARN_ON(devres_release(dev, devm_attr_group_remove,
2103 devm_attr_group_match,
2104 /* cast away const */ (void *)grp));
2106 EXPORT_SYMBOL_GPL(devm_device_remove_group);
2109 * devm_device_add_groups - create a bunch of managed attribute groups
2110 * @dev: The device to create the group for
2111 * @groups: The attribute groups to create, NULL terminated
2113 * This function creates a bunch of managed attribute groups. If an error
2114 * occurs when creating a group, all previously created groups will be
2115 * removed, unwinding everything back to the original state when this
2116 * function was called. It will explicitly warn and error if any of the
2117 * attribute files being created already exist.
2119 * Returns 0 on success or error code from sysfs_create_group on failure.
2121 int devm_device_add_groups(struct device *dev,
2122 const struct attribute_group **groups)
2124 union device_attr_group_devres *devres;
2127 devres = devres_alloc(devm_attr_groups_remove,
2128 sizeof(*devres), GFP_KERNEL);
2132 error = sysfs_create_groups(&dev->kobj, groups);
2134 devres_free(devres);
2138 devres->groups = groups;
2139 devres_add(dev, devres);
2142 EXPORT_SYMBOL_GPL(devm_device_add_groups);
2145 * devm_device_remove_groups - remove a list of managed groups
2147 * @dev: The device for the groups to be removed from
2148 * @groups: NULL terminated list of groups to be removed
2150 * If groups is not NULL, remove the specified groups from the device.
2152 void devm_device_remove_groups(struct device *dev,
2153 const struct attribute_group **groups)
2155 WARN_ON(devres_release(dev, devm_attr_groups_remove,
2156 devm_attr_group_match,
2157 /* cast away const */ (void *)groups));
2159 EXPORT_SYMBOL_GPL(devm_device_remove_groups);
2161 static int device_add_attrs(struct device *dev)
2163 struct class *class = dev->class;
2164 const struct device_type *type = dev->type;
2168 error = device_add_groups(dev, class->dev_groups);
2174 error = device_add_groups(dev, type->groups);
2176 goto err_remove_class_groups;
2179 error = device_add_groups(dev, dev->groups);
2181 goto err_remove_type_groups;
2183 if (device_supports_offline(dev) && !dev->offline_disabled) {
2184 error = device_create_file(dev, &dev_attr_online);
2186 goto err_remove_dev_groups;
2189 if (fw_devlink_flags && !fw_devlink_is_permissive()) {
2190 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2192 goto err_remove_dev_online;
2197 err_remove_dev_online:
2198 device_remove_file(dev, &dev_attr_online);
2199 err_remove_dev_groups:
2200 device_remove_groups(dev, dev->groups);
2201 err_remove_type_groups:
2203 device_remove_groups(dev, type->groups);
2204 err_remove_class_groups:
2206 device_remove_groups(dev, class->dev_groups);
2211 static void device_remove_attrs(struct device *dev)
2213 struct class *class = dev->class;
2214 const struct device_type *type = dev->type;
2216 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2217 device_remove_file(dev, &dev_attr_online);
2218 device_remove_groups(dev, dev->groups);
2221 device_remove_groups(dev, type->groups);
2224 device_remove_groups(dev, class->dev_groups);
2227 static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2230 return print_dev_t(buf, dev->devt);
2232 static DEVICE_ATTR_RO(dev);
2235 struct kset *devices_kset;
2238 * devices_kset_move_before - Move device in the devices_kset's list.
2239 * @deva: Device to move.
2240 * @devb: Device @deva should come before.
2242 static void devices_kset_move_before(struct device *deva, struct device *devb)
2246 pr_debug("devices_kset: Moving %s before %s\n",
2247 dev_name(deva), dev_name(devb));
2248 spin_lock(&devices_kset->list_lock);
2249 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2250 spin_unlock(&devices_kset->list_lock);
2254 * devices_kset_move_after - Move device in the devices_kset's list.
2255 * @deva: Device to move
2256 * @devb: Device @deva should come after.
2258 static void devices_kset_move_after(struct device *deva, struct device *devb)
2262 pr_debug("devices_kset: Moving %s after %s\n",
2263 dev_name(deva), dev_name(devb));
2264 spin_lock(&devices_kset->list_lock);
2265 list_move(&deva->kobj.entry, &devb->kobj.entry);
2266 spin_unlock(&devices_kset->list_lock);
2270 * devices_kset_move_last - move the device to the end of devices_kset's list.
2271 * @dev: device to move
2273 void devices_kset_move_last(struct device *dev)
2277 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2278 spin_lock(&devices_kset->list_lock);
2279 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2280 spin_unlock(&devices_kset->list_lock);
2284 * device_create_file - create sysfs attribute file for device.
2286 * @attr: device attribute descriptor.
2288 int device_create_file(struct device *dev,
2289 const struct device_attribute *attr)
2294 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2295 "Attribute %s: write permission without 'store'\n",
2297 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2298 "Attribute %s: read permission without 'show'\n",
2300 error = sysfs_create_file(&dev->kobj, &attr->attr);
2305 EXPORT_SYMBOL_GPL(device_create_file);
2308 * device_remove_file - remove sysfs attribute file.
2310 * @attr: device attribute descriptor.
2312 void device_remove_file(struct device *dev,
2313 const struct device_attribute *attr)
2316 sysfs_remove_file(&dev->kobj, &attr->attr);
2318 EXPORT_SYMBOL_GPL(device_remove_file);
2321 * device_remove_file_self - remove sysfs attribute file from its own method.
2323 * @attr: device attribute descriptor.
2325 * See kernfs_remove_self() for details.
2327 bool device_remove_file_self(struct device *dev,
2328 const struct device_attribute *attr)
2331 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2335 EXPORT_SYMBOL_GPL(device_remove_file_self);
2338 * device_create_bin_file - create sysfs binary attribute file for device.
2340 * @attr: device binary attribute descriptor.
2342 int device_create_bin_file(struct device *dev,
2343 const struct bin_attribute *attr)
2345 int error = -EINVAL;
2347 error = sysfs_create_bin_file(&dev->kobj, attr);
2350 EXPORT_SYMBOL_GPL(device_create_bin_file);
2353 * device_remove_bin_file - remove sysfs binary attribute file
2355 * @attr: device binary attribute descriptor.
2357 void device_remove_bin_file(struct device *dev,
2358 const struct bin_attribute *attr)
2361 sysfs_remove_bin_file(&dev->kobj, attr);
2363 EXPORT_SYMBOL_GPL(device_remove_bin_file);
2365 static void klist_children_get(struct klist_node *n)
2367 struct device_private *p = to_device_private_parent(n);
2368 struct device *dev = p->device;
2373 static void klist_children_put(struct klist_node *n)
2375 struct device_private *p = to_device_private_parent(n);
2376 struct device *dev = p->device;
2382 * device_initialize - init device structure.
2385 * This prepares the device for use by other layers by initializing
2387 * It is the first half of device_register(), if called by
2388 * that function, though it can also be called separately, so one
2389 * may use @dev's fields. In particular, get_device()/put_device()
2390 * may be used for reference counting of @dev after calling this
2393 * All fields in @dev must be initialized by the caller to 0, except
2394 * for those explicitly set to some other value. The simplest
2395 * approach is to use kzalloc() to allocate the structure containing
2398 * NOTE: Use put_device() to give up your reference instead of freeing
2399 * @dev directly once you have called this function.
2401 void device_initialize(struct device *dev)
2403 dev->kobj.kset = devices_kset;
2404 kobject_init(&dev->kobj, &device_ktype);
2405 INIT_LIST_HEAD(&dev->dma_pools);
2406 mutex_init(&dev->mutex);
2407 #ifdef CONFIG_PROVE_LOCKING
2408 mutex_init(&dev->lockdep_mutex);
2410 lockdep_set_novalidate_class(&dev->mutex);
2411 spin_lock_init(&dev->devres_lock);
2412 INIT_LIST_HEAD(&dev->devres_head);
2413 device_pm_init(dev);
2414 set_dev_node(dev, -1);
2415 #ifdef CONFIG_GENERIC_MSI_IRQ
2416 INIT_LIST_HEAD(&dev->msi_list);
2418 INIT_LIST_HEAD(&dev->links.consumers);
2419 INIT_LIST_HEAD(&dev->links.suppliers);
2420 INIT_LIST_HEAD(&dev->links.needs_suppliers);
2421 INIT_LIST_HEAD(&dev->links.defer_hook);
2422 dev->links.status = DL_DEV_NO_DRIVER;
2424 EXPORT_SYMBOL_GPL(device_initialize);
2426 struct kobject *virtual_device_parent(struct device *dev)
2428 static struct kobject *virtual_dir = NULL;
2431 virtual_dir = kobject_create_and_add("virtual",
2432 &devices_kset->kobj);
2438 struct kobject kobj;
2439 struct class *class;
2442 #define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2444 static void class_dir_release(struct kobject *kobj)
2446 struct class_dir *dir = to_class_dir(kobj);
2451 struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
2453 struct class_dir *dir = to_class_dir(kobj);
2454 return dir->class->ns_type;
2457 static struct kobj_type class_dir_ktype = {
2458 .release = class_dir_release,
2459 .sysfs_ops = &kobj_sysfs_ops,
2460 .child_ns_type = class_dir_child_ns_type
2463 static struct kobject *
2464 class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
2466 struct class_dir *dir;
2469 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
2471 return ERR_PTR(-ENOMEM);
2474 kobject_init(&dir->kobj, &class_dir_ktype);
2476 dir->kobj.kset = &class->p->glue_dirs;
2478 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
2480 kobject_put(&dir->kobj);
2481 return ERR_PTR(retval);
2486 static DEFINE_MUTEX(gdp_mutex);
2488 static struct kobject *get_device_parent(struct device *dev,
2489 struct device *parent)
2492 struct kobject *kobj = NULL;
2493 struct kobject *parent_kobj;
2497 /* block disks show up in /sys/block */
2498 if (sysfs_deprecated && dev->class == &block_class) {
2499 if (parent && parent->class == &block_class)
2500 return &parent->kobj;
2501 return &block_class.p->subsys.kobj;
2506 * If we have no parent, we live in "virtual".
2507 * Class-devices with a non class-device as parent, live
2508 * in a "glue" directory to prevent namespace collisions.
2511 parent_kobj = virtual_device_parent(dev);
2512 else if (parent->class && !dev->class->ns_type)
2513 return &parent->kobj;
2515 parent_kobj = &parent->kobj;
2517 mutex_lock(&gdp_mutex);
2519 /* find our class-directory at the parent and reference it */
2520 spin_lock(&dev->class->p->glue_dirs.list_lock);
2521 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
2522 if (k->parent == parent_kobj) {
2523 kobj = kobject_get(k);
2526 spin_unlock(&dev->class->p->glue_dirs.list_lock);
2528 mutex_unlock(&gdp_mutex);
2532 /* or create a new class-directory at the parent device */
2533 k = class_dir_create_and_add(dev->class, parent_kobj);
2534 /* do not emit an uevent for this simple "glue" directory */
2535 mutex_unlock(&gdp_mutex);
2539 /* subsystems can specify a default root directory for their devices */
2540 if (!parent && dev->bus && dev->bus->dev_root)
2541 return &dev->bus->dev_root->kobj;
2544 return &parent->kobj;
2548 static inline bool live_in_glue_dir(struct kobject *kobj,
2551 if (!kobj || !dev->class ||
2552 kobj->kset != &dev->class->p->glue_dirs)
2557 static inline struct kobject *get_glue_dir(struct device *dev)
2559 return dev->kobj.parent;
2563 * make sure cleaning up dir as the last step, we need to make
2564 * sure .release handler of kobject is run with holding the
2567 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
2571 /* see if we live in a "glue" directory */
2572 if (!live_in_glue_dir(glue_dir, dev))
2575 mutex_lock(&gdp_mutex);
2577 * There is a race condition between removing glue directory
2578 * and adding a new device under the glue directory.
2583 * get_device_parent()
2584 * class_dir_create_and_add()
2585 * kobject_add_internal()
2586 * create_dir() // create glue_dir
2589 * get_device_parent()
2590 * kobject_get() // get glue_dir
2593 * cleanup_glue_dir()
2594 * kobject_del(glue_dir)
2597 * kobject_add_internal()
2598 * create_dir() // in glue_dir
2599 * sysfs_create_dir_ns()
2600 * kernfs_create_dir_ns(sd)
2602 * sysfs_remove_dir() // glue_dir->sd=NULL
2603 * sysfs_put() // free glue_dir->sd
2606 * kernfs_new_node(sd)
2607 * kernfs_get(glue_dir)
2611 * Before CPU1 remove last child device under glue dir, if CPU2 add
2612 * a new device under glue dir, the glue_dir kobject reference count
2613 * will be increase to 2 in kobject_get(k). And CPU2 has been called
2614 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
2615 * and sysfs_put(). This result in glue_dir->sd is freed.
2617 * Then the CPU2 will see a stale "empty" but still potentially used
2618 * glue dir around in kernfs_new_node().
2620 * In order to avoid this happening, we also should make sure that
2621 * kernfs_node for glue_dir is released in CPU1 only when refcount
2622 * for glue_dir kobj is 1.
2624 ref = kref_read(&glue_dir->kref);
2625 if (!kobject_has_children(glue_dir) && !--ref)
2626 kobject_del(glue_dir);
2627 kobject_put(glue_dir);
2628 mutex_unlock(&gdp_mutex);
2631 static int device_add_class_symlinks(struct device *dev)
2633 struct device_node *of_node = dev_of_node(dev);
2637 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
2639 dev_warn(dev, "Error %d creating of_node link\n",error);
2640 /* An error here doesn't warrant bringing down the device */
2646 error = sysfs_create_link(&dev->kobj,
2647 &dev->class->p->subsys.kobj,
2652 if (dev->parent && device_is_not_partition(dev)) {
2653 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
2660 /* /sys/block has directories and does not need symlinks */
2661 if (sysfs_deprecated && dev->class == &block_class)
2665 /* link in the class directory pointing to the device */
2666 error = sysfs_create_link(&dev->class->p->subsys.kobj,
2667 &dev->kobj, dev_name(dev));
2674 sysfs_remove_link(&dev->kobj, "device");
2677 sysfs_remove_link(&dev->kobj, "subsystem");
2679 sysfs_remove_link(&dev->kobj, "of_node");
2683 static void device_remove_class_symlinks(struct device *dev)
2685 if (dev_of_node(dev))
2686 sysfs_remove_link(&dev->kobj, "of_node");
2691 if (dev->parent && device_is_not_partition(dev))
2692 sysfs_remove_link(&dev->kobj, "device");
2693 sysfs_remove_link(&dev->kobj, "subsystem");
2695 if (sysfs_deprecated && dev->class == &block_class)
2698 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
2702 * dev_set_name - set a device name
2704 * @fmt: format string for the device's name
2706 int dev_set_name(struct device *dev, const char *fmt, ...)
2711 va_start(vargs, fmt);
2712 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
2716 EXPORT_SYMBOL_GPL(dev_set_name);
2719 * device_to_dev_kobj - select a /sys/dev/ directory for the device
2722 * By default we select char/ for new entries. Setting class->dev_obj
2723 * to NULL prevents an entry from being created. class->dev_kobj must
2724 * be set (or cleared) before any devices are registered to the class
2725 * otherwise device_create_sys_dev_entry() and
2726 * device_remove_sys_dev_entry() will disagree about the presence of
2729 static struct kobject *device_to_dev_kobj(struct device *dev)
2731 struct kobject *kobj;
2734 kobj = dev->class->dev_kobj;
2736 kobj = sysfs_dev_char_kobj;
2741 static int device_create_sys_dev_entry(struct device *dev)
2743 struct kobject *kobj = device_to_dev_kobj(dev);
2748 format_dev_t(devt_str, dev->devt);
2749 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
2755 static void device_remove_sys_dev_entry(struct device *dev)
2757 struct kobject *kobj = device_to_dev_kobj(dev);
2761 format_dev_t(devt_str, dev->devt);
2762 sysfs_remove_link(kobj, devt_str);
2766 static int device_private_init(struct device *dev)
2768 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
2771 dev->p->device = dev;
2772 klist_init(&dev->p->klist_children, klist_children_get,
2773 klist_children_put);
2774 INIT_LIST_HEAD(&dev->p->deferred_probe);
2779 * device_add - add device to device hierarchy.
2782 * This is part 2 of device_register(), though may be called
2783 * separately _iff_ device_initialize() has been called separately.
2785 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
2786 * to the global and sibling lists for the device, then
2787 * adds it to the other relevant subsystems of the driver model.
2789 * Do not call this routine or device_register() more than once for
2790 * any device structure. The driver model core is not designed to work
2791 * with devices that get unregistered and then spring back to life.
2792 * (Among other things, it's very hard to guarantee that all references
2793 * to the previous incarnation of @dev have been dropped.) Allocate
2794 * and register a fresh new struct device instead.
2796 * NOTE: _Never_ directly free @dev after calling this function, even
2797 * if it returned an error! Always use put_device() to give up your
2798 * reference instead.
2800 * Rule of thumb is: if device_add() succeeds, you should call
2801 * device_del() when you want to get rid of it. If device_add() has
2802 * *not* succeeded, use *only* put_device() to drop the reference
2805 int device_add(struct device *dev)
2807 struct device *parent;
2808 struct kobject *kobj;
2809 struct class_interface *class_intf;
2810 int error = -EINVAL;
2811 struct kobject *glue_dir = NULL;
2813 dev = get_device(dev);
2818 error = device_private_init(dev);
2824 * for statically allocated devices, which should all be converted
2825 * some day, we need to initialize the name. We prevent reading back
2826 * the name, and force the use of dev_name()
2828 if (dev->init_name) {
2829 dev_set_name(dev, "%s", dev->init_name);
2830 dev->init_name = NULL;
2833 /* subsystems can specify simple device enumeration */
2834 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
2835 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
2837 if (!dev_name(dev)) {
2842 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
2844 parent = get_device(dev->parent);
2845 kobj = get_device_parent(dev, parent);
2847 error = PTR_ERR(kobj);
2851 dev->kobj.parent = kobj;
2853 /* use parent numa_node */
2854 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
2855 set_dev_node(dev, dev_to_node(parent));
2857 /* first, register with generic layer. */
2858 /* we require the name to be set before, and pass NULL */
2859 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
2861 glue_dir = get_glue_dir(dev);
2865 /* notify platform of device entry */
2866 error = device_platform_notify(dev, KOBJ_ADD);
2868 goto platform_error;
2870 error = device_create_file(dev, &dev_attr_uevent);
2874 error = device_add_class_symlinks(dev);
2877 error = device_add_attrs(dev);
2880 error = bus_add_device(dev);
2883 error = dpm_sysfs_add(dev);
2888 if (MAJOR(dev->devt)) {
2889 error = device_create_file(dev, &dev_attr_dev);
2893 error = device_create_sys_dev_entry(dev);
2897 devtmpfs_create_node(dev);
2900 /* Notify clients of device addition. This call must come
2901 * after dpm_sysfs_add() and before kobject_uevent().
2904 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
2905 BUS_NOTIFY_ADD_DEVICE, dev);
2907 kobject_uevent(&dev->kobj, KOBJ_ADD);
2910 * Check if any of the other devices (consumers) have been waiting for
2911 * this device (supplier) to be added so that they can create a device
2914 * This needs to happen after device_pm_add() because device_link_add()
2915 * requires the supplier be registered before it's called.
2917 * But this also needs to happen before bus_probe_device() to make sure
2918 * waiting consumers can link to it before the driver is bound to the
2919 * device and the driver sync_state callback is called for this device.
2921 if (dev->fwnode && !dev->fwnode->dev) {
2922 dev->fwnode->dev = dev;
2923 fw_devlink_link_device(dev);
2926 bus_probe_device(dev);
2928 klist_add_tail(&dev->p->knode_parent,
2929 &parent->p->klist_children);
2932 mutex_lock(&dev->class->p->mutex);
2933 /* tie the class to the device */
2934 klist_add_tail(&dev->p->knode_class,
2935 &dev->class->p->klist_devices);
2937 /* notify any interfaces that the device is here */
2938 list_for_each_entry(class_intf,
2939 &dev->class->p->interfaces, node)
2940 if (class_intf->add_dev)
2941 class_intf->add_dev(dev, class_intf);
2942 mutex_unlock(&dev->class->p->mutex);
2948 if (MAJOR(dev->devt))
2949 device_remove_file(dev, &dev_attr_dev);
2951 device_pm_remove(dev);
2952 dpm_sysfs_remove(dev);
2954 bus_remove_device(dev);
2956 device_remove_attrs(dev);
2958 device_remove_class_symlinks(dev);
2960 device_remove_file(dev, &dev_attr_uevent);
2962 device_platform_notify(dev, KOBJ_REMOVE);
2964 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
2965 glue_dir = get_glue_dir(dev);
2966 kobject_del(&dev->kobj);
2968 cleanup_glue_dir(dev, glue_dir);
2976 EXPORT_SYMBOL_GPL(device_add);
2979 * device_register - register a device with the system.
2980 * @dev: pointer to the device structure
2982 * This happens in two clean steps - initialize the device
2983 * and add it to the system. The two steps can be called
2984 * separately, but this is the easiest and most common.
2985 * I.e. you should only call the two helpers separately if
2986 * have a clearly defined need to use and refcount the device
2987 * before it is added to the hierarchy.
2989 * For more information, see the kerneldoc for device_initialize()
2992 * NOTE: _Never_ directly free @dev after calling this function, even
2993 * if it returned an error! Always use put_device() to give up the
2994 * reference initialized in this function instead.
2996 int device_register(struct device *dev)
2998 device_initialize(dev);
2999 return device_add(dev);
3001 EXPORT_SYMBOL_GPL(device_register);
3004 * get_device - increment reference count for device.
3007 * This simply forwards the call to kobject_get(), though
3008 * we do take care to provide for the case that we get a NULL
3009 * pointer passed in.
3011 struct device *get_device(struct device *dev)
3013 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3015 EXPORT_SYMBOL_GPL(get_device);
3018 * put_device - decrement reference count.
3019 * @dev: device in question.
3021 void put_device(struct device *dev)
3023 /* might_sleep(); */
3025 kobject_put(&dev->kobj);
3027 EXPORT_SYMBOL_GPL(put_device);
3029 bool kill_device(struct device *dev)
3032 * Require the device lock and set the "dead" flag to guarantee that
3033 * the update behavior is consistent with the other bitfields near
3034 * it and that we cannot have an asynchronous probe routine trying
3035 * to run while we are tearing out the bus/class/sysfs from
3036 * underneath the device.
3038 lockdep_assert_held(&dev->mutex);
3042 dev->p->dead = true;
3045 EXPORT_SYMBOL_GPL(kill_device);
3048 * device_del - delete device from system.
3051 * This is the first part of the device unregistration
3052 * sequence. This removes the device from the lists we control
3053 * from here, has it removed from the other driver model
3054 * subsystems it was added to in device_add(), and removes it
3055 * from the kobject hierarchy.
3057 * NOTE: this should be called manually _iff_ device_add() was
3058 * also called manually.
3060 void device_del(struct device *dev)
3062 struct device *parent = dev->parent;
3063 struct kobject *glue_dir = NULL;
3064 struct class_interface *class_intf;
3070 if (dev->fwnode && dev->fwnode->dev == dev)
3071 dev->fwnode->dev = NULL;
3073 /* Notify clients of device removal. This call must come
3074 * before dpm_sysfs_remove().
3077 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3078 BUS_NOTIFY_DEL_DEVICE, dev);
3080 dpm_sysfs_remove(dev);
3082 klist_del(&dev->p->knode_parent);
3083 if (MAJOR(dev->devt)) {
3084 devtmpfs_delete_node(dev);
3085 device_remove_sys_dev_entry(dev);
3086 device_remove_file(dev, &dev_attr_dev);
3089 device_remove_class_symlinks(dev);
3091 mutex_lock(&dev->class->p->mutex);
3092 /* notify any interfaces that the device is now gone */
3093 list_for_each_entry(class_intf,
3094 &dev->class->p->interfaces, node)
3095 if (class_intf->remove_dev)
3096 class_intf->remove_dev(dev, class_intf);
3097 /* remove the device from the class list */
3098 klist_del(&dev->p->knode_class);
3099 mutex_unlock(&dev->class->p->mutex);
3101 device_remove_file(dev, &dev_attr_uevent);
3102 device_remove_attrs(dev);
3103 bus_remove_device(dev);
3104 device_pm_remove(dev);
3105 driver_deferred_probe_del(dev);
3106 device_platform_notify(dev, KOBJ_REMOVE);
3107 device_remove_properties(dev);
3108 device_links_purge(dev);
3111 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3112 BUS_NOTIFY_REMOVED_DEVICE, dev);
3113 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3114 glue_dir = get_glue_dir(dev);
3115 kobject_del(&dev->kobj);
3116 cleanup_glue_dir(dev, glue_dir);
3119 EXPORT_SYMBOL_GPL(device_del);
3122 * device_unregister - unregister device from system.
3123 * @dev: device going away.
3125 * We do this in two parts, like we do device_register(). First,
3126 * we remove it from all the subsystems with device_del(), then
3127 * we decrement the reference count via put_device(). If that
3128 * is the final reference count, the device will be cleaned up
3129 * via device_release() above. Otherwise, the structure will
3130 * stick around until the final reference to the device is dropped.
3132 void device_unregister(struct device *dev)
3134 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3138 EXPORT_SYMBOL_GPL(device_unregister);
3140 static struct device *prev_device(struct klist_iter *i)
3142 struct klist_node *n = klist_prev(i);
3143 struct device *dev = NULL;
3144 struct device_private *p;
3147 p = to_device_private_parent(n);
3153 static struct device *next_device(struct klist_iter *i)
3155 struct klist_node *n = klist_next(i);
3156 struct device *dev = NULL;
3157 struct device_private *p;
3160 p = to_device_private_parent(n);
3167 * device_get_devnode - path of device node file
3169 * @mode: returned file access mode
3170 * @uid: returned file owner
3171 * @gid: returned file group
3172 * @tmp: possibly allocated string
3174 * Return the relative path of a possible device node.
3175 * Non-default names may need to allocate a memory to compose
3176 * a name. This memory is returned in tmp and needs to be
3177 * freed by the caller.
3179 const char *device_get_devnode(struct device *dev,
3180 umode_t *mode, kuid_t *uid, kgid_t *gid,
3187 /* the device type may provide a specific name */
3188 if (dev->type && dev->type->devnode)
3189 *tmp = dev->type->devnode(dev, mode, uid, gid);
3193 /* the class may provide a specific name */
3194 if (dev->class && dev->class->devnode)
3195 *tmp = dev->class->devnode(dev, mode);
3199 /* return name without allocation, tmp == NULL */
3200 if (strchr(dev_name(dev), '!') == NULL)
3201 return dev_name(dev);
3203 /* replace '!' in the name with '/' */
3204 s = kstrdup(dev_name(dev), GFP_KERNEL);
3207 strreplace(s, '!', '/');
3212 * device_for_each_child - device child iterator.
3213 * @parent: parent struct device.
3214 * @fn: function to be called for each device.
3215 * @data: data for the callback.
3217 * Iterate over @parent's child devices, and call @fn for each,
3220 * We check the return of @fn each time. If it returns anything
3221 * other than 0, we break out and return that value.
3223 int device_for_each_child(struct device *parent, void *data,
3224 int (*fn)(struct device *dev, void *data))
3226 struct klist_iter i;
3227 struct device *child;
3233 klist_iter_init(&parent->p->klist_children, &i);
3234 while (!error && (child = next_device(&i)))
3235 error = fn(child, data);
3236 klist_iter_exit(&i);
3239 EXPORT_SYMBOL_GPL(device_for_each_child);
3242 * device_for_each_child_reverse - device child iterator in reversed order.
3243 * @parent: parent struct device.
3244 * @fn: function to be called for each device.
3245 * @data: data for the callback.
3247 * Iterate over @parent's child devices, and call @fn for each,
3250 * We check the return of @fn each time. If it returns anything
3251 * other than 0, we break out and return that value.
3253 int device_for_each_child_reverse(struct device *parent, void *data,
3254 int (*fn)(struct device *dev, void *data))
3256 struct klist_iter i;
3257 struct device *child;
3263 klist_iter_init(&parent->p->klist_children, &i);
3264 while ((child = prev_device(&i)) && !error)
3265 error = fn(child, data);
3266 klist_iter_exit(&i);
3269 EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3272 * device_find_child - device iterator for locating a particular device.
3273 * @parent: parent struct device
3274 * @match: Callback function to check device
3275 * @data: Data to pass to match function
3277 * This is similar to the device_for_each_child() function above, but it
3278 * returns a reference to a device that is 'found' for later use, as
3279 * determined by the @match callback.
3281 * The callback should return 0 if the device doesn't match and non-zero
3282 * if it does. If the callback returns non-zero and a reference to the
3283 * current device can be obtained, this function will return to the caller
3284 * and not iterate over any more devices.
3286 * NOTE: you will need to drop the reference with put_device() after use.
3288 struct device *device_find_child(struct device *parent, void *data,
3289 int (*match)(struct device *dev, void *data))
3291 struct klist_iter i;
3292 struct device *child;
3297 klist_iter_init(&parent->p->klist_children, &i);
3298 while ((child = next_device(&i)))
3299 if (match(child, data) && get_device(child))
3301 klist_iter_exit(&i);
3304 EXPORT_SYMBOL_GPL(device_find_child);
3307 * device_find_child_by_name - device iterator for locating a child device.
3308 * @parent: parent struct device
3309 * @name: name of the child device
3311 * This is similar to the device_find_child() function above, but it
3312 * returns a reference to a device that has the name @name.
3314 * NOTE: you will need to drop the reference with put_device() after use.
3316 struct device *device_find_child_by_name(struct device *parent,
3319 struct klist_iter i;
3320 struct device *child;
3325 klist_iter_init(&parent->p->klist_children, &i);
3326 while ((child = next_device(&i)))
3327 if (!strcmp(dev_name(child), name) && get_device(child))
3329 klist_iter_exit(&i);
3332 EXPORT_SYMBOL_GPL(device_find_child_by_name);
3334 int __init devices_init(void)
3336 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3339 dev_kobj = kobject_create_and_add("dev", NULL);
3342 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3343 if (!sysfs_dev_block_kobj)
3344 goto block_kobj_err;
3345 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3346 if (!sysfs_dev_char_kobj)
3352 kobject_put(sysfs_dev_block_kobj);
3354 kobject_put(dev_kobj);
3356 kset_unregister(devices_kset);
3360 static int device_check_offline(struct device *dev, void *not_used)
3364 ret = device_for_each_child(dev, NULL, device_check_offline);
3368 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3372 * device_offline - Prepare the device for hot-removal.
3373 * @dev: Device to be put offline.
3375 * Execute the device bus type's .offline() callback, if present, to prepare
3376 * the device for a subsequent hot-removal. If that succeeds, the device must
3377 * not be used until either it is removed or its bus type's .online() callback
3380 * Call under device_hotplug_lock.
3382 int device_offline(struct device *dev)
3386 if (dev->offline_disabled)
3389 ret = device_for_each_child(dev, NULL, device_check_offline);
3394 if (device_supports_offline(dev)) {
3398 ret = dev->bus->offline(dev);
3400 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3401 dev->offline = true;
3411 * device_online - Put the device back online after successful device_offline().
3412 * @dev: Device to be put back online.
3414 * If device_offline() has been successfully executed for @dev, but the device
3415 * has not been removed subsequently, execute its bus type's .online() callback
3416 * to indicate that the device can be used again.
3418 * Call under device_hotplug_lock.
3420 int device_online(struct device *dev)
3425 if (device_supports_offline(dev)) {
3427 ret = dev->bus->online(dev);
3429 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
3430 dev->offline = false;
3441 struct root_device {
3443 struct module *owner;
3446 static inline struct root_device *to_root_device(struct device *d)
3448 return container_of(d, struct root_device, dev);
3451 static void root_device_release(struct device *dev)
3453 kfree(to_root_device(dev));
3457 * __root_device_register - allocate and register a root device
3458 * @name: root device name
3459 * @owner: owner module of the root device, usually THIS_MODULE
3461 * This function allocates a root device and registers it
3462 * using device_register(). In order to free the returned
3463 * device, use root_device_unregister().
3465 * Root devices are dummy devices which allow other devices
3466 * to be grouped under /sys/devices. Use this function to
3467 * allocate a root device and then use it as the parent of
3468 * any device which should appear under /sys/devices/{name}
3470 * The /sys/devices/{name} directory will also contain a
3471 * 'module' symlink which points to the @owner directory
3474 * Returns &struct device pointer on success, or ERR_PTR() on error.
3476 * Note: You probably want to use root_device_register().
3478 struct device *__root_device_register(const char *name, struct module *owner)
3480 struct root_device *root;
3483 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
3485 return ERR_PTR(err);
3487 err = dev_set_name(&root->dev, "%s", name);
3490 return ERR_PTR(err);
3493 root->dev.release = root_device_release;
3495 err = device_register(&root->dev);
3497 put_device(&root->dev);
3498 return ERR_PTR(err);
3501 #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
3503 struct module_kobject *mk = &owner->mkobj;
3505 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
3507 device_unregister(&root->dev);
3508 return ERR_PTR(err);
3510 root->owner = owner;
3516 EXPORT_SYMBOL_GPL(__root_device_register);
3519 * root_device_unregister - unregister and free a root device
3520 * @dev: device going away
3522 * This function unregisters and cleans up a device that was created by
3523 * root_device_register().
3525 void root_device_unregister(struct device *dev)
3527 struct root_device *root = to_root_device(dev);
3530 sysfs_remove_link(&root->dev.kobj, "module");
3532 device_unregister(dev);
3534 EXPORT_SYMBOL_GPL(root_device_unregister);
3537 static void device_create_release(struct device *dev)
3539 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3543 static __printf(6, 0) struct device *
3544 device_create_groups_vargs(struct class *class, struct device *parent,
3545 dev_t devt, void *drvdata,
3546 const struct attribute_group **groups,
3547 const char *fmt, va_list args)
3549 struct device *dev = NULL;
3550 int retval = -ENODEV;
3552 if (class == NULL || IS_ERR(class))
3555 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3561 device_initialize(dev);
3564 dev->parent = parent;
3565 dev->groups = groups;
3566 dev->release = device_create_release;
3567 dev_set_drvdata(dev, drvdata);
3569 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
3573 retval = device_add(dev);
3581 return ERR_PTR(retval);
3585 * device_create - creates a device and registers it with sysfs
3586 * @class: pointer to the struct class that this device should be registered to
3587 * @parent: pointer to the parent struct device of this new device, if any
3588 * @devt: the dev_t for the char device to be added
3589 * @drvdata: the data to be added to the device for callbacks
3590 * @fmt: string for the device's name
3592 * This function can be used by char device classes. A struct device
3593 * will be created in sysfs, registered to the specified class.
3595 * A "dev" file will be created, showing the dev_t for the device, if
3596 * the dev_t is not 0,0.
3597 * If a pointer to a parent struct device is passed in, the newly created
3598 * struct device will be a child of that device in sysfs.
3599 * The pointer to the struct device will be returned from the call.
3600 * Any further sysfs files that might be required can be created using this
3603 * Returns &struct device pointer on success, or ERR_PTR() on error.
3605 * Note: the struct class passed to this function must have previously
3606 * been created with a call to class_create().
3608 struct device *device_create(struct class *class, struct device *parent,
3609 dev_t devt, void *drvdata, const char *fmt, ...)
3614 va_start(vargs, fmt);
3615 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
3620 EXPORT_SYMBOL_GPL(device_create);
3623 * device_create_with_groups - creates a device and registers it with sysfs
3624 * @class: pointer to the struct class that this device should be registered to
3625 * @parent: pointer to the parent struct device of this new device, if any
3626 * @devt: the dev_t for the char device to be added
3627 * @drvdata: the data to be added to the device for callbacks
3628 * @groups: NULL-terminated list of attribute groups to be created
3629 * @fmt: string for the device's name
3631 * This function can be used by char device classes. A struct device
3632 * will be created in sysfs, registered to the specified class.
3633 * Additional attributes specified in the groups parameter will also
3634 * be created automatically.
3636 * A "dev" file will be created, showing the dev_t for the device, if
3637 * the dev_t is not 0,0.
3638 * If a pointer to a parent struct device is passed in, the newly created
3639 * struct device will be a child of that device in sysfs.
3640 * The pointer to the struct device will be returned from the call.
3641 * Any further sysfs files that might be required can be created using this
3644 * Returns &struct device pointer on success, or ERR_PTR() on error.
3646 * Note: the struct class passed to this function must have previously
3647 * been created with a call to class_create().
3649 struct device *device_create_with_groups(struct class *class,
3650 struct device *parent, dev_t devt,
3652 const struct attribute_group **groups,
3653 const char *fmt, ...)
3658 va_start(vargs, fmt);
3659 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
3664 EXPORT_SYMBOL_GPL(device_create_with_groups);
3667 * device_destroy - removes a device that was created with device_create()
3668 * @class: pointer to the struct class that this device was registered with
3669 * @devt: the dev_t of the device that was previously registered
3671 * This call unregisters and cleans up a device that was created with a
3672 * call to device_create().
3674 void device_destroy(struct class *class, dev_t devt)
3678 dev = class_find_device_by_devt(class, devt);
3681 device_unregister(dev);
3684 EXPORT_SYMBOL_GPL(device_destroy);
3687 * device_rename - renames a device
3688 * @dev: the pointer to the struct device to be renamed
3689 * @new_name: the new name of the device
3691 * It is the responsibility of the caller to provide mutual
3692 * exclusion between two different calls of device_rename
3693 * on the same device to ensure that new_name is valid and
3694 * won't conflict with other devices.
3696 * Note: Don't call this function. Currently, the networking layer calls this
3697 * function, but that will change. The following text from Kay Sievers offers
3700 * Renaming devices is racy at many levels, symlinks and other stuff are not
3701 * replaced atomically, and you get a "move" uevent, but it's not easy to
3702 * connect the event to the old and new device. Device nodes are not renamed at
3703 * all, there isn't even support for that in the kernel now.
3705 * In the meantime, during renaming, your target name might be taken by another
3706 * driver, creating conflicts. Or the old name is taken directly after you
3707 * renamed it -- then you get events for the same DEVPATH, before you even see
3708 * the "move" event. It's just a mess, and nothing new should ever rely on
3709 * kernel device renaming. Besides that, it's not even implemented now for
3710 * other things than (driver-core wise very simple) network devices.
3712 * We are currently about to change network renaming in udev to completely
3713 * disallow renaming of devices in the same namespace as the kernel uses,
3714 * because we can't solve the problems properly, that arise with swapping names
3715 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
3716 * be allowed to some other name than eth[0-9]*, for the aforementioned
3719 * Make up a "real" name in the driver before you register anything, or add
3720 * some other attributes for userspace to find the device, or use udev to add
3721 * symlinks -- but never rename kernel devices later, it's a complete mess. We
3722 * don't even want to get into that and try to implement the missing pieces in
3723 * the core. We really have other pieces to fix in the driver core mess. :)
3725 int device_rename(struct device *dev, const char *new_name)
3727 struct kobject *kobj = &dev->kobj;
3728 char *old_device_name = NULL;
3731 dev = get_device(dev);
3735 dev_dbg(dev, "renaming to %s\n", new_name);
3737 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
3738 if (!old_device_name) {
3744 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
3745 kobj, old_device_name,
3746 new_name, kobject_namespace(kobj));
3751 error = kobject_rename(kobj, new_name);
3758 kfree(old_device_name);
3762 EXPORT_SYMBOL_GPL(device_rename);
3764 static int device_move_class_links(struct device *dev,
3765 struct device *old_parent,
3766 struct device *new_parent)
3771 sysfs_remove_link(&dev->kobj, "device");
3773 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
3779 * device_move - moves a device to a new parent
3780 * @dev: the pointer to the struct device to be moved
3781 * @new_parent: the new parent of the device (can be NULL)
3782 * @dpm_order: how to reorder the dpm_list
3784 int device_move(struct device *dev, struct device *new_parent,
3785 enum dpm_order dpm_order)
3788 struct device *old_parent;
3789 struct kobject *new_parent_kobj;
3791 dev = get_device(dev);
3796 new_parent = get_device(new_parent);
3797 new_parent_kobj = get_device_parent(dev, new_parent);
3798 if (IS_ERR(new_parent_kobj)) {
3799 error = PTR_ERR(new_parent_kobj);
3800 put_device(new_parent);
3804 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
3805 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
3806 error = kobject_move(&dev->kobj, new_parent_kobj);
3808 cleanup_glue_dir(dev, new_parent_kobj);
3809 put_device(new_parent);
3812 old_parent = dev->parent;
3813 dev->parent = new_parent;
3815 klist_remove(&dev->p->knode_parent);
3817 klist_add_tail(&dev->p->knode_parent,
3818 &new_parent->p->klist_children);
3819 set_dev_node(dev, dev_to_node(new_parent));
3823 error = device_move_class_links(dev, old_parent, new_parent);
3825 /* We ignore errors on cleanup since we're hosed anyway... */
3826 device_move_class_links(dev, new_parent, old_parent);
3827 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
3829 klist_remove(&dev->p->knode_parent);
3830 dev->parent = old_parent;
3832 klist_add_tail(&dev->p->knode_parent,
3833 &old_parent->p->klist_children);
3834 set_dev_node(dev, dev_to_node(old_parent));
3837 cleanup_glue_dir(dev, new_parent_kobj);
3838 put_device(new_parent);
3842 switch (dpm_order) {
3843 case DPM_ORDER_NONE:
3845 case DPM_ORDER_DEV_AFTER_PARENT:
3846 device_pm_move_after(dev, new_parent);
3847 devices_kset_move_after(dev, new_parent);
3849 case DPM_ORDER_PARENT_BEFORE_DEV:
3850 device_pm_move_before(new_parent, dev);
3851 devices_kset_move_before(new_parent, dev);
3853 case DPM_ORDER_DEV_LAST:
3854 device_pm_move_last(dev);
3855 devices_kset_move_last(dev);
3859 put_device(old_parent);
3865 EXPORT_SYMBOL_GPL(device_move);
3867 static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
3870 struct kobject *kobj = &dev->kobj;
3871 struct class *class = dev->class;
3872 const struct device_type *type = dev->type;
3877 * Change the device groups of the device class for @dev to
3880 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
3888 * Change the device groups of the device type for @dev to
3891 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
3897 /* Change the device groups of @dev to @kuid/@kgid. */
3898 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
3902 if (device_supports_offline(dev) && !dev->offline_disabled) {
3903 /* Change online device attributes of @dev to @kuid/@kgid. */
3904 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
3914 * device_change_owner - change the owner of an existing device.
3916 * @kuid: new owner's kuid
3917 * @kgid: new owner's kgid
3919 * This changes the owner of @dev and its corresponding sysfs entries to
3920 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
3923 * Returns 0 on success or error code on failure.
3925 int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
3928 struct kobject *kobj = &dev->kobj;
3930 dev = get_device(dev);
3935 * Change the kobject and the default attributes and groups of the
3936 * ktype associated with it to @kuid/@kgid.
3938 error = sysfs_change_owner(kobj, kuid, kgid);
3943 * Change the uevent file for @dev to the new owner. The uevent file
3944 * was created in a separate step when @dev got added and we mirror
3947 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
3953 * Change the device groups, the device groups associated with the
3954 * device class, and the groups associated with the device type of @dev
3957 error = device_attrs_change_owner(dev, kuid, kgid);
3961 error = dpm_sysfs_change_owner(dev, kuid, kgid);
3966 if (sysfs_deprecated && dev->class == &block_class)
3971 * Change the owner of the symlink located in the class directory of
3972 * the device class associated with @dev which points to the actual
3973 * directory entry for @dev to @kuid/@kgid. This ensures that the
3974 * symlink shows the same permissions as its target.
3976 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
3977 dev_name(dev), kuid, kgid);
3985 EXPORT_SYMBOL_GPL(device_change_owner);
3988 * device_shutdown - call ->shutdown() on each device to shutdown.
3990 void device_shutdown(void)
3992 struct device *dev, *parent;
3994 wait_for_device_probe();
3995 device_block_probing();
3999 spin_lock(&devices_kset->list_lock);
4001 * Walk the devices list backward, shutting down each in turn.
4002 * Beware that device unplug events may also start pulling
4003 * devices offline, even as the system is shutting down.
4005 while (!list_empty(&devices_kset->list)) {
4006 dev = list_entry(devices_kset->list.prev, struct device,
4010 * hold reference count of device's parent to
4011 * prevent it from being freed because parent's
4012 * lock is to be held
4014 parent = get_device(dev->parent);
4017 * Make sure the device is off the kset list, in the
4018 * event that dev->*->shutdown() doesn't remove it.
4020 list_del_init(&dev->kobj.entry);
4021 spin_unlock(&devices_kset->list_lock);
4023 /* hold lock to avoid race with probe/release */
4025 device_lock(parent);
4028 /* Don't allow any more runtime suspends */
4029 pm_runtime_get_noresume(dev);
4030 pm_runtime_barrier(dev);
4032 if (dev->class && dev->class->shutdown_pre) {
4034 dev_info(dev, "shutdown_pre\n");
4035 dev->class->shutdown_pre(dev);
4037 if (dev->bus && dev->bus->shutdown) {
4039 dev_info(dev, "shutdown\n");
4040 dev->bus->shutdown(dev);
4041 } else if (dev->driver && dev->driver->shutdown) {
4043 dev_info(dev, "shutdown\n");
4044 dev->driver->shutdown(dev);
4049 device_unlock(parent);
4054 spin_lock(&devices_kset->list_lock);
4056 spin_unlock(&devices_kset->list_lock);
4060 * Device logging functions
4063 #ifdef CONFIG_PRINTK
4065 set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4069 memset(dev_info, 0, sizeof(*dev_info));
4072 subsys = dev->class->name;
4074 subsys = dev->bus->name;
4078 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4081 * Add device identifier DEVICE=:
4085 * +sound:card0 subsystem:devname
4087 if (MAJOR(dev->devt)) {
4090 if (strcmp(subsys, "block") == 0)
4095 snprintf(dev_info->device, sizeof(dev_info->device),
4096 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4097 } else if (strcmp(subsys, "net") == 0) {
4098 struct net_device *net = to_net_dev(dev);
4100 snprintf(dev_info->device, sizeof(dev_info->device),
4101 "n%u", net->ifindex);
4103 snprintf(dev_info->device, sizeof(dev_info->device),
4104 "+%s:%s", subsys, dev_name(dev));
4108 int dev_vprintk_emit(int level, const struct device *dev,
4109 const char *fmt, va_list args)
4111 struct dev_printk_info dev_info;
4113 set_dev_info(dev, &dev_info);
4115 return vprintk_emit(0, level, &dev_info, fmt, args);
4117 EXPORT_SYMBOL(dev_vprintk_emit);
4119 int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4124 va_start(args, fmt);
4126 r = dev_vprintk_emit(level, dev, fmt, args);
4132 EXPORT_SYMBOL(dev_printk_emit);
4134 static void __dev_printk(const char *level, const struct device *dev,
4135 struct va_format *vaf)
4138 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4139 dev_driver_string(dev), dev_name(dev), vaf);
4141 printk("%s(NULL device *): %pV", level, vaf);
4144 void dev_printk(const char *level, const struct device *dev,
4145 const char *fmt, ...)
4147 struct va_format vaf;
4150 va_start(args, fmt);
4155 __dev_printk(level, dev, &vaf);
4159 EXPORT_SYMBOL(dev_printk);
4161 #define define_dev_printk_level(func, kern_level) \
4162 void func(const struct device *dev, const char *fmt, ...) \
4164 struct va_format vaf; \
4167 va_start(args, fmt); \
4172 __dev_printk(kern_level, dev, &vaf); \
4176 EXPORT_SYMBOL(func);
4178 define_dev_printk_level(_dev_emerg, KERN_EMERG);
4179 define_dev_printk_level(_dev_alert, KERN_ALERT);
4180 define_dev_printk_level(_dev_crit, KERN_CRIT);
4181 define_dev_printk_level(_dev_err, KERN_ERR);
4182 define_dev_printk_level(_dev_warn, KERN_WARNING);
4183 define_dev_printk_level(_dev_notice, KERN_NOTICE);
4184 define_dev_printk_level(_dev_info, KERN_INFO);
4189 * dev_err_probe - probe error check and log helper
4190 * @dev: the pointer to the struct device
4191 * @err: error value to test
4192 * @fmt: printf-style format string
4193 * @...: arguments as specified in the format string
4195 * This helper implements common pattern present in probe functions for error
4196 * checking: print debug or error message depending if the error value is
4197 * -EPROBE_DEFER and propagate error upwards.
4198 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4199 * checked later by reading devices_deferred debugfs attribute.
4200 * It replaces code sequence:
4201 * if (err != -EPROBE_DEFER)
4202 * dev_err(dev, ...);
4204 * dev_dbg(dev, ...);
4207 * return dev_err_probe(dev, err, ...);
4212 int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4214 struct va_format vaf;
4217 va_start(args, fmt);
4221 if (err != -EPROBE_DEFER) {
4222 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4224 device_set_deferred_probe_reason(dev, &vaf);
4225 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4232 EXPORT_SYMBOL_GPL(dev_err_probe);
4234 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4236 return fwnode && !IS_ERR(fwnode->secondary);
4240 * set_primary_fwnode - Change the primary firmware node of a given device.
4241 * @dev: Device to handle.
4242 * @fwnode: New primary firmware node of the device.
4244 * Set the device's firmware node pointer to @fwnode, but if a secondary
4245 * firmware node of the device is present, preserve it.
4247 void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4249 struct fwnode_handle *fn = dev->fwnode;
4252 if (fwnode_is_primary(fn))
4256 WARN_ON(fwnode->secondary);
4257 fwnode->secondary = fn;
4259 dev->fwnode = fwnode;
4261 if (fwnode_is_primary(fn)) {
4262 dev->fwnode = fn->secondary;
4263 fn->secondary = NULL;
4269 EXPORT_SYMBOL_GPL(set_primary_fwnode);
4272 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4273 * @dev: Device to handle.
4274 * @fwnode: New secondary firmware node of the device.
4276 * If a primary firmware node of the device is present, set its secondary
4277 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4280 void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4283 fwnode->secondary = ERR_PTR(-ENODEV);
4285 if (fwnode_is_primary(dev->fwnode))
4286 dev->fwnode->secondary = fwnode;
4288 dev->fwnode = fwnode;
4290 EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4293 * device_set_of_node_from_dev - reuse device-tree node of another device
4294 * @dev: device whose device-tree node is being set
4295 * @dev2: device whose device-tree node is being reused
4297 * Takes another reference to the new device-tree node after first dropping
4298 * any reference held to the old node.
4300 void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4302 of_node_put(dev->of_node);
4303 dev->of_node = of_node_get(dev2->of_node);
4304 dev->of_node_reused = true;
4306 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4308 int device_match_name(struct device *dev, const void *name)
4310 return sysfs_streq(dev_name(dev), name);
4312 EXPORT_SYMBOL_GPL(device_match_name);
4314 int device_match_of_node(struct device *dev, const void *np)
4316 return dev->of_node == np;
4318 EXPORT_SYMBOL_GPL(device_match_of_node);
4320 int device_match_fwnode(struct device *dev, const void *fwnode)
4322 return dev_fwnode(dev) == fwnode;
4324 EXPORT_SYMBOL_GPL(device_match_fwnode);
4326 int device_match_devt(struct device *dev, const void *pdevt)
4328 return dev->devt == *(dev_t *)pdevt;
4330 EXPORT_SYMBOL_GPL(device_match_devt);
4332 int device_match_acpi_dev(struct device *dev, const void *adev)
4334 return ACPI_COMPANION(dev) == adev;
4336 EXPORT_SYMBOL(device_match_acpi_dev);
4338 int device_match_any(struct device *dev, const void *unused)
4342 EXPORT_SYMBOL_GPL(device_match_any);