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/sched/mm.h>
30 #include <linux/sysfs.h>
31 #include <linux/dma-map-ops.h> /* for dma_default_coherent */
34 #include "power/power.h"
36 #ifdef CONFIG_SYSFS_DEPRECATED
37 #ifdef CONFIG_SYSFS_DEPRECATED_V2
38 long sysfs_deprecated = 1;
40 long sysfs_deprecated = 0;
42 static int __init sysfs_deprecated_setup(char *arg)
44 return kstrtol(arg, 10, &sysfs_deprecated);
46 early_param("sysfs.deprecated", sysfs_deprecated_setup);
49 /* Device links support. */
50 static LIST_HEAD(deferred_sync);
51 static unsigned int defer_sync_state_count = 1;
52 static DEFINE_MUTEX(fwnode_link_lock);
53 static bool fw_devlink_is_permissive(void);
54 static bool fw_devlink_drv_reg_done;
57 * fwnode_link_add - Create a link between two fwnode_handles.
58 * @con: Consumer end of the link.
59 * @sup: Supplier end of the link.
61 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
62 * represents the detail that the firmware lists @sup fwnode as supplying a
65 * The driver core will use the fwnode link to create a device link between the
66 * two device objects corresponding to @con and @sup when they are created. The
67 * driver core will automatically delete the fwnode link between @con and @sup
70 * Attempts to create duplicate links between the same pair of fwnode handles
71 * are ignored and there is no reference counting.
73 int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
75 struct fwnode_link *link;
78 mutex_lock(&fwnode_link_lock);
80 list_for_each_entry(link, &sup->consumers, s_hook)
81 if (link->consumer == con)
84 link = kzalloc(sizeof(*link), GFP_KERNEL);
91 INIT_LIST_HEAD(&link->s_hook);
93 INIT_LIST_HEAD(&link->c_hook);
95 list_add(&link->s_hook, &sup->consumers);
96 list_add(&link->c_hook, &con->suppliers);
98 mutex_unlock(&fwnode_link_lock);
104 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
105 * @fwnode: fwnode whose supplier links need to be deleted
107 * Deletes all supplier links connecting directly to @fwnode.
109 static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
111 struct fwnode_link *link, *tmp;
113 mutex_lock(&fwnode_link_lock);
114 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
115 list_del(&link->s_hook);
116 list_del(&link->c_hook);
119 mutex_unlock(&fwnode_link_lock);
123 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
124 * @fwnode: fwnode whose consumer links need to be deleted
126 * Deletes all consumer links connecting directly to @fwnode.
128 static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
130 struct fwnode_link *link, *tmp;
132 mutex_lock(&fwnode_link_lock);
133 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
134 list_del(&link->s_hook);
135 list_del(&link->c_hook);
138 mutex_unlock(&fwnode_link_lock);
142 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
143 * @fwnode: fwnode whose links needs to be deleted
145 * Deletes all links connecting directly to a fwnode.
147 void fwnode_links_purge(struct fwnode_handle *fwnode)
149 fwnode_links_purge_suppliers(fwnode);
150 fwnode_links_purge_consumers(fwnode);
153 void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
155 struct fwnode_handle *child;
157 /* Don't purge consumer links of an added child */
161 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
162 fwnode_links_purge_consumers(fwnode);
164 fwnode_for_each_available_child_node(fwnode, child)
165 fw_devlink_purge_absent_suppliers(child);
167 EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
170 static DEFINE_MUTEX(device_links_lock);
171 DEFINE_STATIC_SRCU(device_links_srcu);
173 static inline void device_links_write_lock(void)
175 mutex_lock(&device_links_lock);
178 static inline void device_links_write_unlock(void)
180 mutex_unlock(&device_links_lock);
183 int device_links_read_lock(void) __acquires(&device_links_srcu)
185 return srcu_read_lock(&device_links_srcu);
188 void device_links_read_unlock(int idx) __releases(&device_links_srcu)
190 srcu_read_unlock(&device_links_srcu, idx);
193 int device_links_read_lock_held(void)
195 return srcu_read_lock_held(&device_links_srcu);
197 #else /* !CONFIG_SRCU */
198 static DECLARE_RWSEM(device_links_lock);
200 static inline void device_links_write_lock(void)
202 down_write(&device_links_lock);
205 static inline void device_links_write_unlock(void)
207 up_write(&device_links_lock);
210 int device_links_read_lock(void)
212 down_read(&device_links_lock);
216 void device_links_read_unlock(int not_used)
218 up_read(&device_links_lock);
221 #ifdef CONFIG_DEBUG_LOCK_ALLOC
222 int device_links_read_lock_held(void)
224 return lockdep_is_held(&device_links_lock);
227 #endif /* !CONFIG_SRCU */
229 static bool device_is_ancestor(struct device *dev, struct device *target)
231 while (target->parent) {
232 target = target->parent;
240 * device_is_dependent - Check if one device depends on another one
241 * @dev: Device to check dependencies for.
242 * @target: Device to check against.
244 * Check if @target depends on @dev or any device dependent on it (its child or
245 * its consumer etc). Return 1 if that is the case or 0 otherwise.
247 int device_is_dependent(struct device *dev, void *target)
249 struct device_link *link;
253 * The "ancestors" check is needed to catch the case when the target
254 * device has not been completely initialized yet and it is still
255 * missing from the list of children of its parent device.
257 if (dev == target || device_is_ancestor(dev, target))
260 ret = device_for_each_child(dev, target, device_is_dependent);
264 list_for_each_entry(link, &dev->links.consumers, s_node) {
265 if ((link->flags & ~DL_FLAG_INFERRED) ==
266 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
269 if (link->consumer == target)
272 ret = device_is_dependent(link->consumer, target);
279 static void device_link_init_status(struct device_link *link,
280 struct device *consumer,
281 struct device *supplier)
283 switch (supplier->links.status) {
285 switch (consumer->links.status) {
288 * A consumer driver can create a link to a supplier
289 * that has not completed its probing yet as long as it
290 * knows that the supplier is already functional (for
291 * example, it has just acquired some resources from the
294 link->status = DL_STATE_CONSUMER_PROBE;
297 link->status = DL_STATE_DORMANT;
301 case DL_DEV_DRIVER_BOUND:
302 switch (consumer->links.status) {
304 link->status = DL_STATE_CONSUMER_PROBE;
306 case DL_DEV_DRIVER_BOUND:
307 link->status = DL_STATE_ACTIVE;
310 link->status = DL_STATE_AVAILABLE;
314 case DL_DEV_UNBINDING:
315 link->status = DL_STATE_SUPPLIER_UNBIND;
318 link->status = DL_STATE_DORMANT;
323 static int device_reorder_to_tail(struct device *dev, void *not_used)
325 struct device_link *link;
328 * Devices that have not been registered yet will be put to the ends
329 * of the lists during the registration, so skip them here.
331 if (device_is_registered(dev))
332 devices_kset_move_last(dev);
334 if (device_pm_initialized(dev))
335 device_pm_move_last(dev);
337 device_for_each_child(dev, NULL, device_reorder_to_tail);
338 list_for_each_entry(link, &dev->links.consumers, s_node) {
339 if ((link->flags & ~DL_FLAG_INFERRED) ==
340 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
342 device_reorder_to_tail(link->consumer, NULL);
349 * device_pm_move_to_tail - Move set of devices to the end of device lists
350 * @dev: Device to move
352 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
354 * It moves the @dev along with all of its children and all of its consumers
355 * to the ends of the device_kset and dpm_list, recursively.
357 void device_pm_move_to_tail(struct device *dev)
361 idx = device_links_read_lock();
363 device_reorder_to_tail(dev, NULL);
365 device_links_read_unlock(idx);
368 #define to_devlink(dev) container_of((dev), struct device_link, link_dev)
370 static ssize_t status_show(struct device *dev,
371 struct device_attribute *attr, char *buf)
375 switch (to_devlink(dev)->status) {
377 output = "not tracked";
379 case DL_STATE_DORMANT:
382 case DL_STATE_AVAILABLE:
383 output = "available";
385 case DL_STATE_CONSUMER_PROBE:
386 output = "consumer probing";
388 case DL_STATE_ACTIVE:
391 case DL_STATE_SUPPLIER_UNBIND:
392 output = "supplier unbinding";
399 return sysfs_emit(buf, "%s\n", output);
401 static DEVICE_ATTR_RO(status);
403 static ssize_t auto_remove_on_show(struct device *dev,
404 struct device_attribute *attr, char *buf)
406 struct device_link *link = to_devlink(dev);
409 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
410 output = "supplier unbind";
411 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
412 output = "consumer unbind";
416 return sysfs_emit(buf, "%s\n", output);
418 static DEVICE_ATTR_RO(auto_remove_on);
420 static ssize_t runtime_pm_show(struct device *dev,
421 struct device_attribute *attr, char *buf)
423 struct device_link *link = to_devlink(dev);
425 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
427 static DEVICE_ATTR_RO(runtime_pm);
429 static ssize_t sync_state_only_show(struct device *dev,
430 struct device_attribute *attr, char *buf)
432 struct device_link *link = to_devlink(dev);
434 return sysfs_emit(buf, "%d\n",
435 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
437 static DEVICE_ATTR_RO(sync_state_only);
439 static struct attribute *devlink_attrs[] = {
440 &dev_attr_status.attr,
441 &dev_attr_auto_remove_on.attr,
442 &dev_attr_runtime_pm.attr,
443 &dev_attr_sync_state_only.attr,
446 ATTRIBUTE_GROUPS(devlink);
448 static void device_link_free(struct device_link *link)
450 while (refcount_dec_not_one(&link->rpm_active))
451 pm_runtime_put(link->supplier);
453 put_device(link->consumer);
454 put_device(link->supplier);
459 static void __device_link_free_srcu(struct rcu_head *rhead)
461 device_link_free(container_of(rhead, struct device_link, rcu_head));
464 static void devlink_dev_release(struct device *dev)
466 struct device_link *link = to_devlink(dev);
468 call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
471 static void devlink_dev_release(struct device *dev)
473 device_link_free(to_devlink(dev));
477 static struct class devlink_class = {
479 .owner = THIS_MODULE,
480 .dev_groups = devlink_groups,
481 .dev_release = devlink_dev_release,
484 static int devlink_add_symlinks(struct device *dev,
485 struct class_interface *class_intf)
489 struct device_link *link = to_devlink(dev);
490 struct device *sup = link->supplier;
491 struct device *con = link->consumer;
494 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
495 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
497 len += strlen("supplier:") + 1;
498 buf = kzalloc(len, GFP_KERNEL);
502 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
506 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
510 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
511 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
515 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
516 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
523 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
524 sysfs_remove_link(&sup->kobj, buf);
526 sysfs_remove_link(&link->link_dev.kobj, "consumer");
528 sysfs_remove_link(&link->link_dev.kobj, "supplier");
534 static void devlink_remove_symlinks(struct device *dev,
535 struct class_interface *class_intf)
537 struct device_link *link = to_devlink(dev);
539 struct device *sup = link->supplier;
540 struct device *con = link->consumer;
543 sysfs_remove_link(&link->link_dev.kobj, "consumer");
544 sysfs_remove_link(&link->link_dev.kobj, "supplier");
546 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
547 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
549 len += strlen("supplier:") + 1;
550 buf = kzalloc(len, GFP_KERNEL);
552 WARN(1, "Unable to properly free device link symlinks!\n");
556 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
557 sysfs_remove_link(&con->kobj, buf);
558 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
559 sysfs_remove_link(&sup->kobj, buf);
563 static struct class_interface devlink_class_intf = {
564 .class = &devlink_class,
565 .add_dev = devlink_add_symlinks,
566 .remove_dev = devlink_remove_symlinks,
569 static int __init devlink_class_init(void)
573 ret = class_register(&devlink_class);
577 ret = class_interface_register(&devlink_class_intf);
579 class_unregister(&devlink_class);
583 postcore_initcall(devlink_class_init);
585 #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
586 DL_FLAG_AUTOREMOVE_SUPPLIER | \
587 DL_FLAG_AUTOPROBE_CONSUMER | \
588 DL_FLAG_SYNC_STATE_ONLY | \
591 #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
592 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
595 * device_link_add - Create a link between two devices.
596 * @consumer: Consumer end of the link.
597 * @supplier: Supplier end of the link.
598 * @flags: Link flags.
600 * The caller is responsible for the proper synchronization of the link creation
601 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
602 * runtime PM framework to take the link into account. Second, if the
603 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
604 * be forced into the active meta state and reference-counted upon the creation
605 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
608 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
609 * expected to release the link returned by it directly with the help of either
610 * device_link_del() or device_link_remove().
612 * If that flag is not set, however, the caller of this function is handing the
613 * management of the link over to the driver core entirely and its return value
614 * can only be used to check whether or not the link is present. In that case,
615 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
616 * flags can be used to indicate to the driver core when the link can be safely
617 * deleted. Namely, setting one of them in @flags indicates to the driver core
618 * that the link is not going to be used (by the given caller of this function)
619 * after unbinding the consumer or supplier driver, respectively, from its
620 * device, so the link can be deleted at that point. If none of them is set,
621 * the link will be maintained until one of the devices pointed to by it (either
622 * the consumer or the supplier) is unregistered.
624 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
625 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
626 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
627 * be used to request the driver core to automatically probe for a consumer
628 * driver after successfully binding a driver to the supplier device.
630 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
631 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
632 * the same time is invalid and will cause NULL to be returned upfront.
633 * However, if a device link between the given @consumer and @supplier pair
634 * exists already when this function is called for them, the existing link will
635 * be returned regardless of its current type and status (the link's flags may
636 * be modified then). The caller of this function is then expected to treat
637 * the link as though it has just been created, so (in particular) if
638 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
639 * explicitly when not needed any more (as stated above).
641 * A side effect of the link creation is re-ordering of dpm_list and the
642 * devices_kset list by moving the consumer device and all devices depending
643 * on it to the ends of these lists (that does not happen to devices that have
644 * not been registered when this function is called).
646 * The supplier device is required to be registered when this function is called
647 * and NULL will be returned if that is not the case. The consumer device need
648 * not be registered, however.
650 struct device_link *device_link_add(struct device *consumer,
651 struct device *supplier, u32 flags)
653 struct device_link *link;
655 if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS ||
656 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
657 (flags & DL_FLAG_SYNC_STATE_ONLY &&
658 (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) ||
659 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
660 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
661 DL_FLAG_AUTOREMOVE_SUPPLIER)))
664 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
665 if (pm_runtime_get_sync(supplier) < 0) {
666 pm_runtime_put_noidle(supplier);
671 if (!(flags & DL_FLAG_STATELESS))
672 flags |= DL_FLAG_MANAGED;
674 device_links_write_lock();
678 * If the supplier has not been fully registered yet or there is a
679 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
680 * the supplier already in the graph, return NULL. If the link is a
681 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
682 * because it only affects sync_state() callbacks.
684 if (!device_pm_initialized(supplier)
685 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
686 device_is_dependent(consumer, supplier))) {
692 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
693 * So, only create it if the consumer hasn't probed yet.
695 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
696 consumer->links.status != DL_DEV_NO_DRIVER &&
697 consumer->links.status != DL_DEV_PROBING) {
703 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
704 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
705 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
707 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
708 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
710 list_for_each_entry(link, &supplier->links.consumers, s_node) {
711 if (link->consumer != consumer)
714 if (link->flags & DL_FLAG_INFERRED &&
715 !(flags & DL_FLAG_INFERRED))
716 link->flags &= ~DL_FLAG_INFERRED;
718 if (flags & DL_FLAG_PM_RUNTIME) {
719 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
720 pm_runtime_new_link(consumer);
721 link->flags |= DL_FLAG_PM_RUNTIME;
723 if (flags & DL_FLAG_RPM_ACTIVE)
724 refcount_inc(&link->rpm_active);
727 if (flags & DL_FLAG_STATELESS) {
728 kref_get(&link->kref);
729 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
730 !(link->flags & DL_FLAG_STATELESS)) {
731 link->flags |= DL_FLAG_STATELESS;
734 link->flags |= DL_FLAG_STATELESS;
740 * If the life time of the link following from the new flags is
741 * longer than indicated by the flags of the existing link,
742 * update the existing link to stay around longer.
744 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
745 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
746 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
747 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
749 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
750 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
751 DL_FLAG_AUTOREMOVE_SUPPLIER);
753 if (!(link->flags & DL_FLAG_MANAGED)) {
754 kref_get(&link->kref);
755 link->flags |= DL_FLAG_MANAGED;
756 device_link_init_status(link, consumer, supplier);
758 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
759 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
760 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
767 link = kzalloc(sizeof(*link), GFP_KERNEL);
771 refcount_set(&link->rpm_active, 1);
773 get_device(supplier);
774 link->supplier = supplier;
775 INIT_LIST_HEAD(&link->s_node);
776 get_device(consumer);
777 link->consumer = consumer;
778 INIT_LIST_HEAD(&link->c_node);
780 kref_init(&link->kref);
782 link->link_dev.class = &devlink_class;
783 device_set_pm_not_required(&link->link_dev);
784 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
785 dev_bus_name(supplier), dev_name(supplier),
786 dev_bus_name(consumer), dev_name(consumer));
787 if (device_register(&link->link_dev)) {
788 put_device(consumer);
789 put_device(supplier);
795 if (flags & DL_FLAG_PM_RUNTIME) {
796 if (flags & DL_FLAG_RPM_ACTIVE)
797 refcount_inc(&link->rpm_active);
799 pm_runtime_new_link(consumer);
802 /* Determine the initial link state. */
803 if (flags & DL_FLAG_STATELESS)
804 link->status = DL_STATE_NONE;
806 device_link_init_status(link, consumer, supplier);
809 * Some callers expect the link creation during consumer driver probe to
810 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
812 if (link->status == DL_STATE_CONSUMER_PROBE &&
813 flags & DL_FLAG_PM_RUNTIME)
814 pm_runtime_resume(supplier);
816 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
817 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
819 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
821 "Linked as a sync state only consumer to %s\n",
828 * Move the consumer and all of the devices depending on it to the end
829 * of dpm_list and the devices_kset list.
831 * It is necessary to hold dpm_list locked throughout all that or else
832 * we may end up suspending with a wrong ordering of it.
834 device_reorder_to_tail(consumer, NULL);
836 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
840 device_links_write_unlock();
842 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
843 pm_runtime_put(supplier);
847 EXPORT_SYMBOL_GPL(device_link_add);
850 static void __device_link_del(struct kref *kref)
852 struct device_link *link = container_of(kref, struct device_link, kref);
854 dev_dbg(link->consumer, "Dropping the link to %s\n",
855 dev_name(link->supplier));
857 pm_runtime_drop_link(link);
859 list_del_rcu(&link->s_node);
860 list_del_rcu(&link->c_node);
861 device_unregister(&link->link_dev);
863 #else /* !CONFIG_SRCU */
864 static void __device_link_del(struct kref *kref)
866 struct device_link *link = container_of(kref, struct device_link, kref);
868 dev_info(link->consumer, "Dropping the link to %s\n",
869 dev_name(link->supplier));
871 pm_runtime_drop_link(link);
873 list_del(&link->s_node);
874 list_del(&link->c_node);
875 device_unregister(&link->link_dev);
877 #endif /* !CONFIG_SRCU */
879 static void device_link_put_kref(struct device_link *link)
881 if (link->flags & DL_FLAG_STATELESS)
882 kref_put(&link->kref, __device_link_del);
884 WARN(1, "Unable to drop a managed device link reference\n");
888 * device_link_del - Delete a stateless link between two devices.
889 * @link: Device link to delete.
891 * The caller must ensure proper synchronization of this function with runtime
892 * PM. If the link was added multiple times, it needs to be deleted as often.
893 * Care is required for hotplugged devices: Their links are purged on removal
894 * and calling device_link_del() is then no longer allowed.
896 void device_link_del(struct device_link *link)
898 device_links_write_lock();
899 device_link_put_kref(link);
900 device_links_write_unlock();
902 EXPORT_SYMBOL_GPL(device_link_del);
905 * device_link_remove - Delete a stateless link between two devices.
906 * @consumer: Consumer end of the link.
907 * @supplier: Supplier end of the link.
909 * The caller must ensure proper synchronization of this function with runtime
912 void device_link_remove(void *consumer, struct device *supplier)
914 struct device_link *link;
916 if (WARN_ON(consumer == supplier))
919 device_links_write_lock();
921 list_for_each_entry(link, &supplier->links.consumers, s_node) {
922 if (link->consumer == consumer) {
923 device_link_put_kref(link);
928 device_links_write_unlock();
930 EXPORT_SYMBOL_GPL(device_link_remove);
932 static void device_links_missing_supplier(struct device *dev)
934 struct device_link *link;
936 list_for_each_entry(link, &dev->links.suppliers, c_node) {
937 if (link->status != DL_STATE_CONSUMER_PROBE)
940 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
941 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
943 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
944 WRITE_ONCE(link->status, DL_STATE_DORMANT);
950 * device_links_check_suppliers - Check presence of supplier drivers.
951 * @dev: Consumer device.
953 * Check links from this device to any suppliers. Walk the list of the device's
954 * links to suppliers and see if all of them are available. If not, simply
955 * return -EPROBE_DEFER.
957 * We need to guarantee that the supplier will not go away after the check has
958 * been positive here. It only can go away in __device_release_driver() and
959 * that function checks the device's links to consumers. This means we need to
960 * mark the link as "consumer probe in progress" to make the supplier removal
961 * wait for us to complete (or bad things may happen).
963 * Links without the DL_FLAG_MANAGED flag set are ignored.
965 int device_links_check_suppliers(struct device *dev)
967 struct device_link *link;
971 * Device waiting for supplier to become available is not allowed to
974 mutex_lock(&fwnode_link_lock);
975 if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
976 !fw_devlink_is_permissive()) {
977 dev_dbg(dev, "probe deferral - wait for supplier %pfwP\n",
978 list_first_entry(&dev->fwnode->suppliers,
981 mutex_unlock(&fwnode_link_lock);
982 return -EPROBE_DEFER;
984 mutex_unlock(&fwnode_link_lock);
986 device_links_write_lock();
988 list_for_each_entry(link, &dev->links.suppliers, c_node) {
989 if (!(link->flags & DL_FLAG_MANAGED))
992 if (link->status != DL_STATE_AVAILABLE &&
993 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
994 device_links_missing_supplier(dev);
995 dev_dbg(dev, "probe deferral - supplier %s not ready\n",
996 dev_name(link->supplier));
1000 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1002 dev->links.status = DL_DEV_PROBING;
1004 device_links_write_unlock();
1009 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1010 * @dev: Device to call sync_state() on
1011 * @list: List head to queue the @dev on
1013 * Queues a device for a sync_state() callback when the device links write lock
1014 * isn't held. This allows the sync_state() execution flow to use device links
1015 * APIs. The caller must ensure this function is called with
1016 * device_links_write_lock() held.
1018 * This function does a get_device() to make sure the device is not freed while
1021 * So the caller must also ensure that device_links_flush_sync_list() is called
1022 * as soon as the caller releases device_links_write_lock(). This is necessary
1023 * to make sure the sync_state() is called in a timely fashion and the
1024 * put_device() is called on this device.
1026 static void __device_links_queue_sync_state(struct device *dev,
1027 struct list_head *list)
1029 struct device_link *link;
1031 if (!dev_has_sync_state(dev))
1033 if (dev->state_synced)
1036 list_for_each_entry(link, &dev->links.consumers, s_node) {
1037 if (!(link->flags & DL_FLAG_MANAGED))
1039 if (link->status != DL_STATE_ACTIVE)
1044 * Set the flag here to avoid adding the same device to a list more
1045 * than once. This can happen if new consumers get added to the device
1046 * and probed before the list is flushed.
1048 dev->state_synced = true;
1050 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1054 list_add_tail(&dev->links.defer_sync, list);
1058 * device_links_flush_sync_list - Call sync_state() on a list of devices
1059 * @list: List of devices to call sync_state() on
1060 * @dont_lock_dev: Device for which lock is already held by the caller
1062 * Calls sync_state() on all the devices that have been queued for it. This
1063 * function is used in conjunction with __device_links_queue_sync_state(). The
1064 * @dont_lock_dev parameter is useful when this function is called from a
1065 * context where a device lock is already held.
1067 static void device_links_flush_sync_list(struct list_head *list,
1068 struct device *dont_lock_dev)
1070 struct device *dev, *tmp;
1072 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1073 list_del_init(&dev->links.defer_sync);
1075 if (dev != dont_lock_dev)
1078 if (dev->bus->sync_state)
1079 dev->bus->sync_state(dev);
1080 else if (dev->driver && dev->driver->sync_state)
1081 dev->driver->sync_state(dev);
1083 if (dev != dont_lock_dev)
1090 void device_links_supplier_sync_state_pause(void)
1092 device_links_write_lock();
1093 defer_sync_state_count++;
1094 device_links_write_unlock();
1097 void device_links_supplier_sync_state_resume(void)
1099 struct device *dev, *tmp;
1100 LIST_HEAD(sync_list);
1102 device_links_write_lock();
1103 if (!defer_sync_state_count) {
1104 WARN(true, "Unmatched sync_state pause/resume!");
1107 defer_sync_state_count--;
1108 if (defer_sync_state_count)
1111 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1113 * Delete from deferred_sync list before queuing it to
1114 * sync_list because defer_sync is used for both lists.
1116 list_del_init(&dev->links.defer_sync);
1117 __device_links_queue_sync_state(dev, &sync_list);
1120 device_links_write_unlock();
1122 device_links_flush_sync_list(&sync_list, NULL);
1125 static int sync_state_resume_initcall(void)
1127 device_links_supplier_sync_state_resume();
1130 late_initcall(sync_state_resume_initcall);
1132 static void __device_links_supplier_defer_sync(struct device *sup)
1134 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1135 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1138 static void device_link_drop_managed(struct device_link *link)
1140 link->flags &= ~DL_FLAG_MANAGED;
1141 WRITE_ONCE(link->status, DL_STATE_NONE);
1142 kref_put(&link->kref, __device_link_del);
1145 static ssize_t waiting_for_supplier_show(struct device *dev,
1146 struct device_attribute *attr,
1152 val = !list_empty(&dev->fwnode->suppliers);
1154 return sysfs_emit(buf, "%u\n", val);
1156 static DEVICE_ATTR_RO(waiting_for_supplier);
1159 * device_links_force_bind - Prepares device to be force bound
1160 * @dev: Consumer device.
1162 * device_bind_driver() force binds a device to a driver without calling any
1163 * driver probe functions. So the consumer really isn't going to wait for any
1164 * supplier before it's bound to the driver. We still want the device link
1165 * states to be sensible when this happens.
1167 * In preparation for device_bind_driver(), this function goes through each
1168 * supplier device links and checks if the supplier is bound. If it is, then
1169 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1170 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1172 void device_links_force_bind(struct device *dev)
1174 struct device_link *link, *ln;
1176 device_links_write_lock();
1178 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1179 if (!(link->flags & DL_FLAG_MANAGED))
1182 if (link->status != DL_STATE_AVAILABLE) {
1183 device_link_drop_managed(link);
1186 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1188 dev->links.status = DL_DEV_PROBING;
1190 device_links_write_unlock();
1194 * device_links_driver_bound - Update device links after probing its driver.
1195 * @dev: Device to update the links for.
1197 * The probe has been successful, so update links from this device to any
1198 * consumers by changing their status to "available".
1200 * Also change the status of @dev's links to suppliers to "active".
1202 * Links without the DL_FLAG_MANAGED flag set are ignored.
1204 void device_links_driver_bound(struct device *dev)
1206 struct device_link *link, *ln;
1207 LIST_HEAD(sync_list);
1210 * If a device binds successfully, it's expected to have created all
1211 * the device links it needs to or make new device links as it needs
1212 * them. So, fw_devlink no longer needs to create device links to any
1213 * of the device's suppliers.
1215 * Also, if a child firmware node of this bound device is not added as
1216 * a device by now, assume it is never going to be added and make sure
1217 * other devices don't defer probe indefinitely by waiting for such a
1220 if (dev->fwnode && dev->fwnode->dev == dev) {
1221 struct fwnode_handle *child;
1222 fwnode_links_purge_suppliers(dev->fwnode);
1223 fwnode_for_each_available_child_node(dev->fwnode, child)
1224 fw_devlink_purge_absent_suppliers(child);
1226 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1228 device_links_write_lock();
1230 list_for_each_entry(link, &dev->links.consumers, s_node) {
1231 if (!(link->flags & DL_FLAG_MANAGED))
1235 * Links created during consumer probe may be in the "consumer
1236 * probe" state to start with if the supplier is still probing
1237 * when they are created and they may become "active" if the
1238 * consumer probe returns first. Skip them here.
1240 if (link->status == DL_STATE_CONSUMER_PROBE ||
1241 link->status == DL_STATE_ACTIVE)
1244 WARN_ON(link->status != DL_STATE_DORMANT);
1245 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1247 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1248 driver_deferred_probe_add(link->consumer);
1251 if (defer_sync_state_count)
1252 __device_links_supplier_defer_sync(dev);
1254 __device_links_queue_sync_state(dev, &sync_list);
1256 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1257 struct device *supplier;
1259 if (!(link->flags & DL_FLAG_MANAGED))
1262 supplier = link->supplier;
1263 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1265 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1266 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1267 * save to drop the managed link completely.
1269 device_link_drop_managed(link);
1271 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1272 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1276 * This needs to be done even for the deleted
1277 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1278 * device link that was preventing the supplier from getting a
1279 * sync_state() call.
1281 if (defer_sync_state_count)
1282 __device_links_supplier_defer_sync(supplier);
1284 __device_links_queue_sync_state(supplier, &sync_list);
1287 dev->links.status = DL_DEV_DRIVER_BOUND;
1289 device_links_write_unlock();
1291 device_links_flush_sync_list(&sync_list, dev);
1295 * __device_links_no_driver - Update links of a device without a driver.
1296 * @dev: Device without a drvier.
1298 * Delete all non-persistent links from this device to any suppliers.
1300 * Persistent links stay around, but their status is changed to "available",
1301 * unless they already are in the "supplier unbind in progress" state in which
1302 * case they need not be updated.
1304 * Links without the DL_FLAG_MANAGED flag set are ignored.
1306 static void __device_links_no_driver(struct device *dev)
1308 struct device_link *link, *ln;
1310 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1311 if (!(link->flags & DL_FLAG_MANAGED))
1314 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1315 device_link_drop_managed(link);
1319 if (link->status != DL_STATE_CONSUMER_PROBE &&
1320 link->status != DL_STATE_ACTIVE)
1323 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1324 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1326 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1327 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1331 dev->links.status = DL_DEV_NO_DRIVER;
1335 * device_links_no_driver - Update links after failing driver probe.
1336 * @dev: Device whose driver has just failed to probe.
1338 * Clean up leftover links to consumers for @dev and invoke
1339 * %__device_links_no_driver() to update links to suppliers for it as
1342 * Links without the DL_FLAG_MANAGED flag set are ignored.
1344 void device_links_no_driver(struct device *dev)
1346 struct device_link *link;
1348 device_links_write_lock();
1350 list_for_each_entry(link, &dev->links.consumers, s_node) {
1351 if (!(link->flags & DL_FLAG_MANAGED))
1355 * The probe has failed, so if the status of the link is
1356 * "consumer probe" or "active", it must have been added by
1357 * a probing consumer while this device was still probing.
1358 * Change its state to "dormant", as it represents a valid
1359 * relationship, but it is not functionally meaningful.
1361 if (link->status == DL_STATE_CONSUMER_PROBE ||
1362 link->status == DL_STATE_ACTIVE)
1363 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1366 __device_links_no_driver(dev);
1368 device_links_write_unlock();
1372 * device_links_driver_cleanup - Update links after driver removal.
1373 * @dev: Device whose driver has just gone away.
1375 * Update links to consumers for @dev by changing their status to "dormant" and
1376 * invoke %__device_links_no_driver() to update links to suppliers for it as
1379 * Links without the DL_FLAG_MANAGED flag set are ignored.
1381 void device_links_driver_cleanup(struct device *dev)
1383 struct device_link *link, *ln;
1385 device_links_write_lock();
1387 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1388 if (!(link->flags & DL_FLAG_MANAGED))
1391 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1392 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1395 * autoremove the links between this @dev and its consumer
1396 * devices that are not active, i.e. where the link state
1397 * has moved to DL_STATE_SUPPLIER_UNBIND.
1399 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1400 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1401 device_link_drop_managed(link);
1403 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1406 list_del_init(&dev->links.defer_sync);
1407 __device_links_no_driver(dev);
1409 device_links_write_unlock();
1413 * device_links_busy - Check if there are any busy links to consumers.
1414 * @dev: Device to check.
1416 * Check each consumer of the device and return 'true' if its link's status
1417 * is one of "consumer probe" or "active" (meaning that the given consumer is
1418 * probing right now or its driver is present). Otherwise, change the link
1419 * state to "supplier unbind" to prevent the consumer from being probed
1420 * successfully going forward.
1422 * Return 'false' if there are no probing or active consumers.
1424 * Links without the DL_FLAG_MANAGED flag set are ignored.
1426 bool device_links_busy(struct device *dev)
1428 struct device_link *link;
1431 device_links_write_lock();
1433 list_for_each_entry(link, &dev->links.consumers, s_node) {
1434 if (!(link->flags & DL_FLAG_MANAGED))
1437 if (link->status == DL_STATE_CONSUMER_PROBE
1438 || link->status == DL_STATE_ACTIVE) {
1442 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1445 dev->links.status = DL_DEV_UNBINDING;
1447 device_links_write_unlock();
1452 * device_links_unbind_consumers - Force unbind consumers of the given device.
1453 * @dev: Device to unbind the consumers of.
1455 * Walk the list of links to consumers for @dev and if any of them is in the
1456 * "consumer probe" state, wait for all device probes in progress to complete
1459 * If that's not the case, change the status of the link to "supplier unbind"
1460 * and check if the link was in the "active" state. If so, force the consumer
1461 * driver to unbind and start over (the consumer will not re-probe as we have
1462 * changed the state of the link already).
1464 * Links without the DL_FLAG_MANAGED flag set are ignored.
1466 void device_links_unbind_consumers(struct device *dev)
1468 struct device_link *link;
1471 device_links_write_lock();
1473 list_for_each_entry(link, &dev->links.consumers, s_node) {
1474 enum device_link_state status;
1476 if (!(link->flags & DL_FLAG_MANAGED) ||
1477 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1480 status = link->status;
1481 if (status == DL_STATE_CONSUMER_PROBE) {
1482 device_links_write_unlock();
1484 wait_for_device_probe();
1487 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1488 if (status == DL_STATE_ACTIVE) {
1489 struct device *consumer = link->consumer;
1491 get_device(consumer);
1493 device_links_write_unlock();
1495 device_release_driver_internal(consumer, NULL,
1497 put_device(consumer);
1502 device_links_write_unlock();
1506 * device_links_purge - Delete existing links to other devices.
1507 * @dev: Target device.
1509 static void device_links_purge(struct device *dev)
1511 struct device_link *link, *ln;
1513 if (dev->class == &devlink_class)
1517 * Delete all of the remaining links from this device to any other
1518 * devices (either consumers or suppliers).
1520 device_links_write_lock();
1522 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1523 WARN_ON(link->status == DL_STATE_ACTIVE);
1524 __device_link_del(&link->kref);
1527 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1528 WARN_ON(link->status != DL_STATE_DORMANT &&
1529 link->status != DL_STATE_NONE);
1530 __device_link_del(&link->kref);
1533 device_links_write_unlock();
1536 #define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1537 DL_FLAG_SYNC_STATE_ONLY)
1538 #define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1539 DL_FLAG_AUTOPROBE_CONSUMER)
1540 #define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1543 static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1544 static int __init fw_devlink_setup(char *arg)
1549 if (strcmp(arg, "off") == 0) {
1550 fw_devlink_flags = 0;
1551 } else if (strcmp(arg, "permissive") == 0) {
1552 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1553 } else if (strcmp(arg, "on") == 0) {
1554 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1555 } else if (strcmp(arg, "rpm") == 0) {
1556 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1560 early_param("fw_devlink", fw_devlink_setup);
1562 static bool fw_devlink_strict;
1563 static int __init fw_devlink_strict_setup(char *arg)
1565 return strtobool(arg, &fw_devlink_strict);
1567 early_param("fw_devlink.strict", fw_devlink_strict_setup);
1569 u32 fw_devlink_get_flags(void)
1571 return fw_devlink_flags;
1574 static bool fw_devlink_is_permissive(void)
1576 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1579 bool fw_devlink_is_strict(void)
1581 return fw_devlink_strict && !fw_devlink_is_permissive();
1584 static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1586 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1589 fwnode_call_int_op(fwnode, add_links);
1590 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1593 static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1595 struct fwnode_handle *child = NULL;
1597 fw_devlink_parse_fwnode(fwnode);
1599 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1600 fw_devlink_parse_fwtree(child);
1603 static void fw_devlink_relax_link(struct device_link *link)
1605 if (!(link->flags & DL_FLAG_INFERRED))
1608 if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE))
1611 pm_runtime_drop_link(link);
1612 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1613 dev_dbg(link->consumer, "Relaxing link with %s\n",
1614 dev_name(link->supplier));
1617 static int fw_devlink_no_driver(struct device *dev, void *data)
1619 struct device_link *link = to_devlink(dev);
1621 if (!link->supplier->can_match)
1622 fw_devlink_relax_link(link);
1627 void fw_devlink_drivers_done(void)
1629 fw_devlink_drv_reg_done = true;
1630 device_links_write_lock();
1631 class_for_each_device(&devlink_class, NULL, NULL,
1632 fw_devlink_no_driver);
1633 device_links_write_unlock();
1636 static void fw_devlink_unblock_consumers(struct device *dev)
1638 struct device_link *link;
1640 if (!fw_devlink_flags || fw_devlink_is_permissive())
1643 device_links_write_lock();
1644 list_for_each_entry(link, &dev->links.consumers, s_node)
1645 fw_devlink_relax_link(link);
1646 device_links_write_unlock();
1650 * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links
1651 * @con: Device to check dependencies for.
1652 * @sup: Device to check against.
1654 * Check if @sup depends on @con or any device dependent on it (its child or
1655 * its consumer etc). When such a cyclic dependency is found, convert all
1656 * device links created solely by fw_devlink into SYNC_STATE_ONLY device links.
1657 * This is the equivalent of doing fw_devlink=permissive just between the
1658 * devices in the cycle. We need to do this because, at this point, fw_devlink
1659 * can't tell which of these dependencies is not a real dependency.
1661 * Return 1 if a cycle is found. Otherwise, return 0.
1663 static int fw_devlink_relax_cycle(struct device *con, void *sup)
1665 struct device_link *link;
1671 ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
1675 list_for_each_entry(link, &con->links.consumers, s_node) {
1676 if ((link->flags & ~DL_FLAG_INFERRED) ==
1677 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
1680 if (!fw_devlink_relax_cycle(link->consumer, sup))
1685 fw_devlink_relax_link(link);
1691 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
1692 * @con: consumer device for the device link
1693 * @sup_handle: fwnode handle of supplier
1694 * @flags: devlink flags
1696 * This function will try to create a device link between the consumer device
1697 * @con and the supplier device represented by @sup_handle.
1699 * The supplier has to be provided as a fwnode because incorrect cycles in
1700 * fwnode links can sometimes cause the supplier device to never be created.
1701 * This function detects such cases and returns an error if it cannot create a
1702 * device link from the consumer to a missing supplier.
1705 * 0 on successfully creating a device link
1706 * -EINVAL if the device link cannot be created as expected
1707 * -EAGAIN if the device link cannot be created right now, but it may be
1708 * possible to do that in the future
1710 static int fw_devlink_create_devlink(struct device *con,
1711 struct fwnode_handle *sup_handle, u32 flags)
1713 struct device *sup_dev;
1716 sup_dev = get_dev_from_fwnode(sup_handle);
1719 * If it's one of those drivers that don't actually bind to
1720 * their device using driver core, then don't wait on this
1721 * supplier device indefinitely.
1723 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
1724 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
1730 * If this fails, it is due to cycles in device links. Just
1731 * give up on this link and treat it as invalid.
1733 if (!device_link_add(con, sup_dev, flags) &&
1734 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
1735 dev_info(con, "Fixing up cyclic dependency with %s\n",
1737 device_links_write_lock();
1738 fw_devlink_relax_cycle(con, sup_dev);
1739 device_links_write_unlock();
1740 device_link_add(con, sup_dev,
1741 FW_DEVLINK_FLAGS_PERMISSIVE);
1748 /* Supplier that's already initialized without a struct device. */
1749 if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
1753 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
1754 * cycles. So cycle detection isn't necessary and shouldn't be
1757 if (flags & DL_FLAG_SYNC_STATE_ONLY)
1761 * If we can't find the supplier device from its fwnode, it might be
1762 * due to a cyclic dependency between fwnodes. Some of these cycles can
1763 * be broken by applying logic. Check for these types of cycles and
1764 * break them so that devices in the cycle probe properly.
1766 * If the supplier's parent is dependent on the consumer, then
1767 * the consumer-supplier dependency is a false dependency. So,
1768 * treat it as an invalid link.
1770 sup_dev = fwnode_get_next_parent_dev(sup_handle);
1771 if (sup_dev && device_is_dependent(con, sup_dev)) {
1772 dev_dbg(con, "Not linking to %pfwP - False link\n",
1777 * Can't check for cycles or no cycles. So let's try
1784 put_device(sup_dev);
1789 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
1790 * @dev: Device that needs to be linked to its consumers
1792 * This function looks at all the consumer fwnodes of @dev and creates device
1793 * links between the consumer device and @dev (supplier).
1795 * If the consumer device has not been added yet, then this function creates a
1796 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
1797 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
1798 * sync_state() callback before the real consumer device gets to be added and
1801 * Once device links are created from the real consumer to @dev (supplier), the
1802 * fwnode links are deleted.
1804 static void __fw_devlink_link_to_consumers(struct device *dev)
1806 struct fwnode_handle *fwnode = dev->fwnode;
1807 struct fwnode_link *link, *tmp;
1809 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
1810 u32 dl_flags = fw_devlink_get_flags();
1811 struct device *con_dev;
1812 bool own_link = true;
1815 con_dev = get_dev_from_fwnode(link->consumer);
1817 * If consumer device is not available yet, make a "proxy"
1818 * SYNC_STATE_ONLY link from the consumer's parent device to
1819 * the supplier device. This is necessary to make sure the
1820 * supplier doesn't get a sync_state() callback before the real
1821 * consumer can create a device link to the supplier.
1823 * This proxy link step is needed to handle the case where the
1824 * consumer's parent device is added before the supplier.
1827 con_dev = fwnode_get_next_parent_dev(link->consumer);
1829 * However, if the consumer's parent device is also the
1830 * parent of the supplier, don't create a
1831 * consumer-supplier link from the parent to its child
1832 * device. Such a dependency is impossible.
1835 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
1836 put_device(con_dev);
1840 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1847 ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags);
1848 put_device(con_dev);
1849 if (!own_link || ret == -EAGAIN)
1852 list_del(&link->s_hook);
1853 list_del(&link->c_hook);
1859 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
1860 * @dev: The consumer device that needs to be linked to its suppliers
1861 * @fwnode: Root of the fwnode tree that is used to create device links
1863 * This function looks at all the supplier fwnodes of fwnode tree rooted at
1864 * @fwnode and creates device links between @dev (consumer) and all the
1865 * supplier devices of the entire fwnode tree at @fwnode.
1867 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
1868 * and the real suppliers of @dev. Once these device links are created, the
1869 * fwnode links are deleted. When such device links are successfully created,
1870 * this function is called recursively on those supplier devices. This is
1871 * needed to detect and break some invalid cycles in fwnode links. See
1872 * fw_devlink_create_devlink() for more details.
1874 * In addition, it also looks at all the suppliers of the entire fwnode tree
1875 * because some of the child devices of @dev that have not been added yet
1876 * (because @dev hasn't probed) might already have their suppliers added to
1877 * driver core. So, this function creates SYNC_STATE_ONLY device links between
1878 * @dev (consumer) and these suppliers to make sure they don't execute their
1879 * sync_state() callbacks before these child devices have a chance to create
1880 * their device links. The fwnode links that correspond to the child devices
1881 * aren't delete because they are needed later to create the device links
1882 * between the real consumer and supplier devices.
1884 static void __fw_devlink_link_to_suppliers(struct device *dev,
1885 struct fwnode_handle *fwnode)
1887 bool own_link = (dev->fwnode == fwnode);
1888 struct fwnode_link *link, *tmp;
1889 struct fwnode_handle *child = NULL;
1893 dl_flags = fw_devlink_get_flags();
1895 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1897 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
1899 struct device *sup_dev;
1900 struct fwnode_handle *sup = link->supplier;
1902 ret = fw_devlink_create_devlink(dev, sup, dl_flags);
1903 if (!own_link || ret == -EAGAIN)
1906 list_del(&link->s_hook);
1907 list_del(&link->c_hook);
1910 /* If no device link was created, nothing more to do. */
1915 * If a device link was successfully created to a supplier, we
1916 * now need to try and link the supplier to all its suppliers.
1918 * This is needed to detect and delete false dependencies in
1919 * fwnode links that haven't been converted to a device link
1920 * yet. See comments in fw_devlink_create_devlink() for more
1921 * details on the false dependency.
1923 * Without deleting these false dependencies, some devices will
1924 * never probe because they'll keep waiting for their false
1925 * dependency fwnode links to be converted to device links.
1927 sup_dev = get_dev_from_fwnode(sup);
1928 __fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode);
1929 put_device(sup_dev);
1933 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
1934 * all the descendants. This proxy link step is needed to handle the
1935 * case where the supplier is added before the consumer's parent device
1938 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1939 __fw_devlink_link_to_suppliers(dev, child);
1942 static void fw_devlink_link_device(struct device *dev)
1944 struct fwnode_handle *fwnode = dev->fwnode;
1946 if (!fw_devlink_flags)
1949 fw_devlink_parse_fwtree(fwnode);
1951 mutex_lock(&fwnode_link_lock);
1952 __fw_devlink_link_to_consumers(dev);
1953 __fw_devlink_link_to_suppliers(dev, fwnode);
1954 mutex_unlock(&fwnode_link_lock);
1957 /* Device links support end. */
1959 int (*platform_notify)(struct device *dev) = NULL;
1960 int (*platform_notify_remove)(struct device *dev) = NULL;
1961 static struct kobject *dev_kobj;
1962 struct kobject *sysfs_dev_char_kobj;
1963 struct kobject *sysfs_dev_block_kobj;
1965 static DEFINE_MUTEX(device_hotplug_lock);
1967 void lock_device_hotplug(void)
1969 mutex_lock(&device_hotplug_lock);
1972 void unlock_device_hotplug(void)
1974 mutex_unlock(&device_hotplug_lock);
1977 int lock_device_hotplug_sysfs(void)
1979 if (mutex_trylock(&device_hotplug_lock))
1982 /* Avoid busy looping (5 ms of sleep should do). */
1984 return restart_syscall();
1988 static inline int device_is_not_partition(struct device *dev)
1990 return !(dev->type == &part_type);
1993 static inline int device_is_not_partition(struct device *dev)
2000 device_platform_notify(struct device *dev, enum kobject_action action)
2004 ret = acpi_platform_notify(dev, action);
2008 ret = software_node_notify(dev, action);
2012 if (platform_notify && action == KOBJ_ADD)
2013 platform_notify(dev);
2014 else if (platform_notify_remove && action == KOBJ_REMOVE)
2015 platform_notify_remove(dev);
2020 * dev_driver_string - Return a device's driver name, if at all possible
2021 * @dev: struct device to get the name of
2023 * Will return the device's driver's name if it is bound to a device. If
2024 * the device is not bound to a driver, it will return the name of the bus
2025 * it is attached to. If it is not attached to a bus either, an empty
2026 * string will be returned.
2028 const char *dev_driver_string(const struct device *dev)
2030 struct device_driver *drv;
2032 /* dev->driver can change to NULL underneath us because of unbinding,
2033 * so be careful about accessing it. dev->bus and dev->class should
2034 * never change once they are set, so they don't need special care.
2036 drv = READ_ONCE(dev->driver);
2037 return drv ? drv->name : dev_bus_name(dev);
2039 EXPORT_SYMBOL(dev_driver_string);
2041 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2043 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2046 struct device_attribute *dev_attr = to_dev_attr(attr);
2047 struct device *dev = kobj_to_dev(kobj);
2051 ret = dev_attr->show(dev, dev_attr, buf);
2052 if (ret >= (ssize_t)PAGE_SIZE) {
2053 printk("dev_attr_show: %pS returned bad count\n",
2059 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2060 const char *buf, size_t count)
2062 struct device_attribute *dev_attr = to_dev_attr(attr);
2063 struct device *dev = kobj_to_dev(kobj);
2066 if (dev_attr->store)
2067 ret = dev_attr->store(dev, dev_attr, buf, count);
2071 static const struct sysfs_ops dev_sysfs_ops = {
2072 .show = dev_attr_show,
2073 .store = dev_attr_store,
2076 #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2078 ssize_t device_store_ulong(struct device *dev,
2079 struct device_attribute *attr,
2080 const char *buf, size_t size)
2082 struct dev_ext_attribute *ea = to_ext_attr(attr);
2086 ret = kstrtoul(buf, 0, &new);
2089 *(unsigned long *)(ea->var) = new;
2090 /* Always return full write size even if we didn't consume all */
2093 EXPORT_SYMBOL_GPL(device_store_ulong);
2095 ssize_t device_show_ulong(struct device *dev,
2096 struct device_attribute *attr,
2099 struct dev_ext_attribute *ea = to_ext_attr(attr);
2100 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2102 EXPORT_SYMBOL_GPL(device_show_ulong);
2104 ssize_t device_store_int(struct device *dev,
2105 struct device_attribute *attr,
2106 const char *buf, size_t size)
2108 struct dev_ext_attribute *ea = to_ext_attr(attr);
2112 ret = kstrtol(buf, 0, &new);
2116 if (new > INT_MAX || new < INT_MIN)
2118 *(int *)(ea->var) = new;
2119 /* Always return full write size even if we didn't consume all */
2122 EXPORT_SYMBOL_GPL(device_store_int);
2124 ssize_t device_show_int(struct device *dev,
2125 struct device_attribute *attr,
2128 struct dev_ext_attribute *ea = to_ext_attr(attr);
2130 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2132 EXPORT_SYMBOL_GPL(device_show_int);
2134 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2135 const char *buf, size_t size)
2137 struct dev_ext_attribute *ea = to_ext_attr(attr);
2139 if (strtobool(buf, ea->var) < 0)
2144 EXPORT_SYMBOL_GPL(device_store_bool);
2146 ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2149 struct dev_ext_attribute *ea = to_ext_attr(attr);
2151 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2153 EXPORT_SYMBOL_GPL(device_show_bool);
2156 * device_release - free device structure.
2157 * @kobj: device's kobject.
2159 * This is called once the reference count for the object
2160 * reaches 0. We forward the call to the device's release
2161 * method, which should handle actually freeing the structure.
2163 static void device_release(struct kobject *kobj)
2165 struct device *dev = kobj_to_dev(kobj);
2166 struct device_private *p = dev->p;
2169 * Some platform devices are driven without driver attached
2170 * and managed resources may have been acquired. Make sure
2171 * all resources are released.
2173 * Drivers still can add resources into device after device
2174 * is deleted but alive, so release devres here to avoid
2175 * possible memory leak.
2177 devres_release_all(dev);
2179 kfree(dev->dma_range_map);
2183 else if (dev->type && dev->type->release)
2184 dev->type->release(dev);
2185 else if (dev->class && dev->class->dev_release)
2186 dev->class->dev_release(dev);
2188 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",
2193 static const void *device_namespace(struct kobject *kobj)
2195 struct device *dev = kobj_to_dev(kobj);
2196 const void *ns = NULL;
2198 if (dev->class && dev->class->ns_type)
2199 ns = dev->class->namespace(dev);
2204 static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2206 struct device *dev = kobj_to_dev(kobj);
2208 if (dev->class && dev->class->get_ownership)
2209 dev->class->get_ownership(dev, uid, gid);
2212 static struct kobj_type device_ktype = {
2213 .release = device_release,
2214 .sysfs_ops = &dev_sysfs_ops,
2215 .namespace = device_namespace,
2216 .get_ownership = device_get_ownership,
2220 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
2222 struct kobj_type *ktype = get_ktype(kobj);
2224 if (ktype == &device_ktype) {
2225 struct device *dev = kobj_to_dev(kobj);
2234 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
2236 struct device *dev = kobj_to_dev(kobj);
2239 return dev->bus->name;
2241 return dev->class->name;
2245 static int dev_uevent(struct kset *kset, struct kobject *kobj,
2246 struct kobj_uevent_env *env)
2248 struct device *dev = kobj_to_dev(kobj);
2251 /* add device node properties if present */
2252 if (MAJOR(dev->devt)) {
2256 kuid_t uid = GLOBAL_ROOT_UID;
2257 kgid_t gid = GLOBAL_ROOT_GID;
2259 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2260 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2261 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2263 add_uevent_var(env, "DEVNAME=%s", name);
2265 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2266 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2267 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2268 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2269 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2274 if (dev->type && dev->type->name)
2275 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2278 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2280 /* Add common DT information about the device */
2281 of_device_uevent(dev, env);
2283 /* have the bus specific function add its stuff */
2284 if (dev->bus && dev->bus->uevent) {
2285 retval = dev->bus->uevent(dev, env);
2287 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2288 dev_name(dev), __func__, retval);
2291 /* have the class specific function add its stuff */
2292 if (dev->class && dev->class->dev_uevent) {
2293 retval = dev->class->dev_uevent(dev, env);
2295 pr_debug("device: '%s': %s: class uevent() "
2296 "returned %d\n", dev_name(dev),
2300 /* have the device type specific function add its stuff */
2301 if (dev->type && dev->type->uevent) {
2302 retval = dev->type->uevent(dev, env);
2304 pr_debug("device: '%s': %s: dev_type uevent() "
2305 "returned %d\n", dev_name(dev),
2312 static const struct kset_uevent_ops device_uevent_ops = {
2313 .filter = dev_uevent_filter,
2314 .name = dev_uevent_name,
2315 .uevent = dev_uevent,
2318 static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2321 struct kobject *top_kobj;
2323 struct kobj_uevent_env *env = NULL;
2328 /* search the kset, the device belongs to */
2329 top_kobj = &dev->kobj;
2330 while (!top_kobj->kset && top_kobj->parent)
2331 top_kobj = top_kobj->parent;
2332 if (!top_kobj->kset)
2335 kset = top_kobj->kset;
2336 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2339 /* respect filter */
2340 if (kset->uevent_ops && kset->uevent_ops->filter)
2341 if (!kset->uevent_ops->filter(kset, &dev->kobj))
2344 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2348 /* let the kset specific function add its keys */
2349 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
2353 /* copy keys to file */
2354 for (i = 0; i < env->envp_idx; i++)
2355 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2361 static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2362 const char *buf, size_t count)
2366 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2369 dev_err(dev, "uevent: failed to send synthetic uevent\n");
2375 static DEVICE_ATTR_RW(uevent);
2377 static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2383 val = !dev->offline;
2385 return sysfs_emit(buf, "%u\n", val);
2388 static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2389 const char *buf, size_t count)
2394 ret = strtobool(buf, &val);
2398 ret = lock_device_hotplug_sysfs();
2402 ret = val ? device_online(dev) : device_offline(dev);
2403 unlock_device_hotplug();
2404 return ret < 0 ? ret : count;
2406 static DEVICE_ATTR_RW(online);
2408 int device_add_groups(struct device *dev, const struct attribute_group **groups)
2410 return sysfs_create_groups(&dev->kobj, groups);
2412 EXPORT_SYMBOL_GPL(device_add_groups);
2414 void device_remove_groups(struct device *dev,
2415 const struct attribute_group **groups)
2417 sysfs_remove_groups(&dev->kobj, groups);
2419 EXPORT_SYMBOL_GPL(device_remove_groups);
2421 union device_attr_group_devres {
2422 const struct attribute_group *group;
2423 const struct attribute_group **groups;
2426 static int devm_attr_group_match(struct device *dev, void *res, void *data)
2428 return ((union device_attr_group_devres *)res)->group == data;
2431 static void devm_attr_group_remove(struct device *dev, void *res)
2433 union device_attr_group_devres *devres = res;
2434 const struct attribute_group *group = devres->group;
2436 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2437 sysfs_remove_group(&dev->kobj, group);
2440 static void devm_attr_groups_remove(struct device *dev, void *res)
2442 union device_attr_group_devres *devres = res;
2443 const struct attribute_group **groups = devres->groups;
2445 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2446 sysfs_remove_groups(&dev->kobj, groups);
2450 * devm_device_add_group - given a device, create a managed attribute group
2451 * @dev: The device to create the group for
2452 * @grp: The attribute group to create
2454 * This function creates a group for the first time. It will explicitly
2455 * warn and error if any of the attribute files being created already exist.
2457 * Returns 0 on success or error code on failure.
2459 int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2461 union device_attr_group_devres *devres;
2464 devres = devres_alloc(devm_attr_group_remove,
2465 sizeof(*devres), GFP_KERNEL);
2469 error = sysfs_create_group(&dev->kobj, grp);
2471 devres_free(devres);
2475 devres->group = grp;
2476 devres_add(dev, devres);
2479 EXPORT_SYMBOL_GPL(devm_device_add_group);
2482 * devm_device_remove_group: remove a managed group from a device
2483 * @dev: device to remove the group from
2484 * @grp: group to remove
2486 * This function removes a group of attributes from a device. The attributes
2487 * previously have to have been created for this group, otherwise it will fail.
2489 void devm_device_remove_group(struct device *dev,
2490 const struct attribute_group *grp)
2492 WARN_ON(devres_release(dev, devm_attr_group_remove,
2493 devm_attr_group_match,
2494 /* cast away const */ (void *)grp));
2496 EXPORT_SYMBOL_GPL(devm_device_remove_group);
2499 * devm_device_add_groups - create a bunch of managed attribute groups
2500 * @dev: The device to create the group for
2501 * @groups: The attribute groups to create, NULL terminated
2503 * This function creates a bunch of managed attribute groups. If an error
2504 * occurs when creating a group, all previously created groups will be
2505 * removed, unwinding everything back to the original state when this
2506 * function was called. It will explicitly warn and error if any of the
2507 * attribute files being created already exist.
2509 * Returns 0 on success or error code from sysfs_create_group on failure.
2511 int devm_device_add_groups(struct device *dev,
2512 const struct attribute_group **groups)
2514 union device_attr_group_devres *devres;
2517 devres = devres_alloc(devm_attr_groups_remove,
2518 sizeof(*devres), GFP_KERNEL);
2522 error = sysfs_create_groups(&dev->kobj, groups);
2524 devres_free(devres);
2528 devres->groups = groups;
2529 devres_add(dev, devres);
2532 EXPORT_SYMBOL_GPL(devm_device_add_groups);
2535 * devm_device_remove_groups - remove a list of managed groups
2537 * @dev: The device for the groups to be removed from
2538 * @groups: NULL terminated list of groups to be removed
2540 * If groups is not NULL, remove the specified groups from the device.
2542 void devm_device_remove_groups(struct device *dev,
2543 const struct attribute_group **groups)
2545 WARN_ON(devres_release(dev, devm_attr_groups_remove,
2546 devm_attr_group_match,
2547 /* cast away const */ (void *)groups));
2549 EXPORT_SYMBOL_GPL(devm_device_remove_groups);
2551 static int device_add_attrs(struct device *dev)
2553 struct class *class = dev->class;
2554 const struct device_type *type = dev->type;
2558 error = device_add_groups(dev, class->dev_groups);
2564 error = device_add_groups(dev, type->groups);
2566 goto err_remove_class_groups;
2569 error = device_add_groups(dev, dev->groups);
2571 goto err_remove_type_groups;
2573 if (device_supports_offline(dev) && !dev->offline_disabled) {
2574 error = device_create_file(dev, &dev_attr_online);
2576 goto err_remove_dev_groups;
2579 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2580 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2582 goto err_remove_dev_online;
2587 err_remove_dev_online:
2588 device_remove_file(dev, &dev_attr_online);
2589 err_remove_dev_groups:
2590 device_remove_groups(dev, dev->groups);
2591 err_remove_type_groups:
2593 device_remove_groups(dev, type->groups);
2594 err_remove_class_groups:
2596 device_remove_groups(dev, class->dev_groups);
2601 static void device_remove_attrs(struct device *dev)
2603 struct class *class = dev->class;
2604 const struct device_type *type = dev->type;
2606 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2607 device_remove_file(dev, &dev_attr_online);
2608 device_remove_groups(dev, dev->groups);
2611 device_remove_groups(dev, type->groups);
2614 device_remove_groups(dev, class->dev_groups);
2617 static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2620 return print_dev_t(buf, dev->devt);
2622 static DEVICE_ATTR_RO(dev);
2625 struct kset *devices_kset;
2628 * devices_kset_move_before - Move device in the devices_kset's list.
2629 * @deva: Device to move.
2630 * @devb: Device @deva should come before.
2632 static void devices_kset_move_before(struct device *deva, struct device *devb)
2636 pr_debug("devices_kset: Moving %s before %s\n",
2637 dev_name(deva), dev_name(devb));
2638 spin_lock(&devices_kset->list_lock);
2639 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2640 spin_unlock(&devices_kset->list_lock);
2644 * devices_kset_move_after - Move device in the devices_kset's list.
2645 * @deva: Device to move
2646 * @devb: Device @deva should come after.
2648 static void devices_kset_move_after(struct device *deva, struct device *devb)
2652 pr_debug("devices_kset: Moving %s after %s\n",
2653 dev_name(deva), dev_name(devb));
2654 spin_lock(&devices_kset->list_lock);
2655 list_move(&deva->kobj.entry, &devb->kobj.entry);
2656 spin_unlock(&devices_kset->list_lock);
2660 * devices_kset_move_last - move the device to the end of devices_kset's list.
2661 * @dev: device to move
2663 void devices_kset_move_last(struct device *dev)
2667 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2668 spin_lock(&devices_kset->list_lock);
2669 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2670 spin_unlock(&devices_kset->list_lock);
2674 * device_create_file - create sysfs attribute file for device.
2676 * @attr: device attribute descriptor.
2678 int device_create_file(struct device *dev,
2679 const struct device_attribute *attr)
2684 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2685 "Attribute %s: write permission without 'store'\n",
2687 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2688 "Attribute %s: read permission without 'show'\n",
2690 error = sysfs_create_file(&dev->kobj, &attr->attr);
2695 EXPORT_SYMBOL_GPL(device_create_file);
2698 * device_remove_file - remove sysfs attribute file.
2700 * @attr: device attribute descriptor.
2702 void device_remove_file(struct device *dev,
2703 const struct device_attribute *attr)
2706 sysfs_remove_file(&dev->kobj, &attr->attr);
2708 EXPORT_SYMBOL_GPL(device_remove_file);
2711 * device_remove_file_self - remove sysfs attribute file from its own method.
2713 * @attr: device attribute descriptor.
2715 * See kernfs_remove_self() for details.
2717 bool device_remove_file_self(struct device *dev,
2718 const struct device_attribute *attr)
2721 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2725 EXPORT_SYMBOL_GPL(device_remove_file_self);
2728 * device_create_bin_file - create sysfs binary attribute file for device.
2730 * @attr: device binary attribute descriptor.
2732 int device_create_bin_file(struct device *dev,
2733 const struct bin_attribute *attr)
2735 int error = -EINVAL;
2737 error = sysfs_create_bin_file(&dev->kobj, attr);
2740 EXPORT_SYMBOL_GPL(device_create_bin_file);
2743 * device_remove_bin_file - remove sysfs binary attribute file
2745 * @attr: device binary attribute descriptor.
2747 void device_remove_bin_file(struct device *dev,
2748 const struct bin_attribute *attr)
2751 sysfs_remove_bin_file(&dev->kobj, attr);
2753 EXPORT_SYMBOL_GPL(device_remove_bin_file);
2755 static void klist_children_get(struct klist_node *n)
2757 struct device_private *p = to_device_private_parent(n);
2758 struct device *dev = p->device;
2763 static void klist_children_put(struct klist_node *n)
2765 struct device_private *p = to_device_private_parent(n);
2766 struct device *dev = p->device;
2772 * device_initialize - init device structure.
2775 * This prepares the device for use by other layers by initializing
2777 * It is the first half of device_register(), if called by
2778 * that function, though it can also be called separately, so one
2779 * may use @dev's fields. In particular, get_device()/put_device()
2780 * may be used for reference counting of @dev after calling this
2783 * All fields in @dev must be initialized by the caller to 0, except
2784 * for those explicitly set to some other value. The simplest
2785 * approach is to use kzalloc() to allocate the structure containing
2788 * NOTE: Use put_device() to give up your reference instead of freeing
2789 * @dev directly once you have called this function.
2791 void device_initialize(struct device *dev)
2793 dev->kobj.kset = devices_kset;
2794 kobject_init(&dev->kobj, &device_ktype);
2795 INIT_LIST_HEAD(&dev->dma_pools);
2796 mutex_init(&dev->mutex);
2797 #ifdef CONFIG_PROVE_LOCKING
2798 mutex_init(&dev->lockdep_mutex);
2800 lockdep_set_novalidate_class(&dev->mutex);
2801 spin_lock_init(&dev->devres_lock);
2802 INIT_LIST_HEAD(&dev->devres_head);
2803 device_pm_init(dev);
2804 set_dev_node(dev, -1);
2805 #ifdef CONFIG_GENERIC_MSI_IRQ
2806 INIT_LIST_HEAD(&dev->msi_list);
2808 INIT_LIST_HEAD(&dev->links.consumers);
2809 INIT_LIST_HEAD(&dev->links.suppliers);
2810 INIT_LIST_HEAD(&dev->links.defer_sync);
2811 dev->links.status = DL_DEV_NO_DRIVER;
2812 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
2813 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
2814 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
2815 dev->dma_coherent = dma_default_coherent;
2818 EXPORT_SYMBOL_GPL(device_initialize);
2820 struct kobject *virtual_device_parent(struct device *dev)
2822 static struct kobject *virtual_dir = NULL;
2825 virtual_dir = kobject_create_and_add("virtual",
2826 &devices_kset->kobj);
2832 struct kobject kobj;
2833 struct class *class;
2836 #define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2838 static void class_dir_release(struct kobject *kobj)
2840 struct class_dir *dir = to_class_dir(kobj);
2845 struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
2847 struct class_dir *dir = to_class_dir(kobj);
2848 return dir->class->ns_type;
2851 static struct kobj_type class_dir_ktype = {
2852 .release = class_dir_release,
2853 .sysfs_ops = &kobj_sysfs_ops,
2854 .child_ns_type = class_dir_child_ns_type
2857 static struct kobject *
2858 class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
2860 struct class_dir *dir;
2863 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
2865 return ERR_PTR(-ENOMEM);
2868 kobject_init(&dir->kobj, &class_dir_ktype);
2870 dir->kobj.kset = &class->p->glue_dirs;
2872 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
2874 kobject_put(&dir->kobj);
2875 return ERR_PTR(retval);
2880 static DEFINE_MUTEX(gdp_mutex);
2882 static struct kobject *get_device_parent(struct device *dev,
2883 struct device *parent)
2886 struct kobject *kobj = NULL;
2887 struct kobject *parent_kobj;
2891 /* block disks show up in /sys/block */
2892 if (sysfs_deprecated && dev->class == &block_class) {
2893 if (parent && parent->class == &block_class)
2894 return &parent->kobj;
2895 return &block_class.p->subsys.kobj;
2900 * If we have no parent, we live in "virtual".
2901 * Class-devices with a non class-device as parent, live
2902 * in a "glue" directory to prevent namespace collisions.
2905 parent_kobj = virtual_device_parent(dev);
2906 else if (parent->class && !dev->class->ns_type)
2907 return &parent->kobj;
2909 parent_kobj = &parent->kobj;
2911 mutex_lock(&gdp_mutex);
2913 /* find our class-directory at the parent and reference it */
2914 spin_lock(&dev->class->p->glue_dirs.list_lock);
2915 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
2916 if (k->parent == parent_kobj) {
2917 kobj = kobject_get(k);
2920 spin_unlock(&dev->class->p->glue_dirs.list_lock);
2922 mutex_unlock(&gdp_mutex);
2926 /* or create a new class-directory at the parent device */
2927 k = class_dir_create_and_add(dev->class, parent_kobj);
2928 /* do not emit an uevent for this simple "glue" directory */
2929 mutex_unlock(&gdp_mutex);
2933 /* subsystems can specify a default root directory for their devices */
2934 if (!parent && dev->bus && dev->bus->dev_root)
2935 return &dev->bus->dev_root->kobj;
2938 return &parent->kobj;
2942 static inline bool live_in_glue_dir(struct kobject *kobj,
2945 if (!kobj || !dev->class ||
2946 kobj->kset != &dev->class->p->glue_dirs)
2951 static inline struct kobject *get_glue_dir(struct device *dev)
2953 return dev->kobj.parent;
2957 * make sure cleaning up dir as the last step, we need to make
2958 * sure .release handler of kobject is run with holding the
2961 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
2965 /* see if we live in a "glue" directory */
2966 if (!live_in_glue_dir(glue_dir, dev))
2969 mutex_lock(&gdp_mutex);
2971 * There is a race condition between removing glue directory
2972 * and adding a new device under the glue directory.
2977 * get_device_parent()
2978 * class_dir_create_and_add()
2979 * kobject_add_internal()
2980 * create_dir() // create glue_dir
2983 * get_device_parent()
2984 * kobject_get() // get glue_dir
2987 * cleanup_glue_dir()
2988 * kobject_del(glue_dir)
2991 * kobject_add_internal()
2992 * create_dir() // in glue_dir
2993 * sysfs_create_dir_ns()
2994 * kernfs_create_dir_ns(sd)
2996 * sysfs_remove_dir() // glue_dir->sd=NULL
2997 * sysfs_put() // free glue_dir->sd
3000 * kernfs_new_node(sd)
3001 * kernfs_get(glue_dir)
3005 * Before CPU1 remove last child device under glue dir, if CPU2 add
3006 * a new device under glue dir, the glue_dir kobject reference count
3007 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3008 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3009 * and sysfs_put(). This result in glue_dir->sd is freed.
3011 * Then the CPU2 will see a stale "empty" but still potentially used
3012 * glue dir around in kernfs_new_node().
3014 * In order to avoid this happening, we also should make sure that
3015 * kernfs_node for glue_dir is released in CPU1 only when refcount
3016 * for glue_dir kobj is 1.
3018 ref = kref_read(&glue_dir->kref);
3019 if (!kobject_has_children(glue_dir) && !--ref)
3020 kobject_del(glue_dir);
3021 kobject_put(glue_dir);
3022 mutex_unlock(&gdp_mutex);
3025 static int device_add_class_symlinks(struct device *dev)
3027 struct device_node *of_node = dev_of_node(dev);
3031 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3033 dev_warn(dev, "Error %d creating of_node link\n",error);
3034 /* An error here doesn't warrant bringing down the device */
3040 error = sysfs_create_link(&dev->kobj,
3041 &dev->class->p->subsys.kobj,
3046 if (dev->parent && device_is_not_partition(dev)) {
3047 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3054 /* /sys/block has directories and does not need symlinks */
3055 if (sysfs_deprecated && dev->class == &block_class)
3059 /* link in the class directory pointing to the device */
3060 error = sysfs_create_link(&dev->class->p->subsys.kobj,
3061 &dev->kobj, dev_name(dev));
3068 sysfs_remove_link(&dev->kobj, "device");
3071 sysfs_remove_link(&dev->kobj, "subsystem");
3073 sysfs_remove_link(&dev->kobj, "of_node");
3077 static void device_remove_class_symlinks(struct device *dev)
3079 if (dev_of_node(dev))
3080 sysfs_remove_link(&dev->kobj, "of_node");
3085 if (dev->parent && device_is_not_partition(dev))
3086 sysfs_remove_link(&dev->kobj, "device");
3087 sysfs_remove_link(&dev->kobj, "subsystem");
3089 if (sysfs_deprecated && dev->class == &block_class)
3092 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
3096 * dev_set_name - set a device name
3098 * @fmt: format string for the device's name
3100 int dev_set_name(struct device *dev, const char *fmt, ...)
3105 va_start(vargs, fmt);
3106 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3110 EXPORT_SYMBOL_GPL(dev_set_name);
3113 * device_to_dev_kobj - select a /sys/dev/ directory for the device
3116 * By default we select char/ for new entries. Setting class->dev_obj
3117 * to NULL prevents an entry from being created. class->dev_kobj must
3118 * be set (or cleared) before any devices are registered to the class
3119 * otherwise device_create_sys_dev_entry() and
3120 * device_remove_sys_dev_entry() will disagree about the presence of
3123 static struct kobject *device_to_dev_kobj(struct device *dev)
3125 struct kobject *kobj;
3128 kobj = dev->class->dev_kobj;
3130 kobj = sysfs_dev_char_kobj;
3135 static int device_create_sys_dev_entry(struct device *dev)
3137 struct kobject *kobj = device_to_dev_kobj(dev);
3142 format_dev_t(devt_str, dev->devt);
3143 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3149 static void device_remove_sys_dev_entry(struct device *dev)
3151 struct kobject *kobj = device_to_dev_kobj(dev);
3155 format_dev_t(devt_str, dev->devt);
3156 sysfs_remove_link(kobj, devt_str);
3160 static int device_private_init(struct device *dev)
3162 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3165 dev->p->device = dev;
3166 klist_init(&dev->p->klist_children, klist_children_get,
3167 klist_children_put);
3168 INIT_LIST_HEAD(&dev->p->deferred_probe);
3173 * device_add - add device to device hierarchy.
3176 * This is part 2 of device_register(), though may be called
3177 * separately _iff_ device_initialize() has been called separately.
3179 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3180 * to the global and sibling lists for the device, then
3181 * adds it to the other relevant subsystems of the driver model.
3183 * Do not call this routine or device_register() more than once for
3184 * any device structure. The driver model core is not designed to work
3185 * with devices that get unregistered and then spring back to life.
3186 * (Among other things, it's very hard to guarantee that all references
3187 * to the previous incarnation of @dev have been dropped.) Allocate
3188 * and register a fresh new struct device instead.
3190 * NOTE: _Never_ directly free @dev after calling this function, even
3191 * if it returned an error! Always use put_device() to give up your
3192 * reference instead.
3194 * Rule of thumb is: if device_add() succeeds, you should call
3195 * device_del() when you want to get rid of it. If device_add() has
3196 * *not* succeeded, use *only* put_device() to drop the reference
3199 int device_add(struct device *dev)
3201 struct device *parent;
3202 struct kobject *kobj;
3203 struct class_interface *class_intf;
3204 int error = -EINVAL;
3205 struct kobject *glue_dir = NULL;
3207 dev = get_device(dev);
3212 error = device_private_init(dev);
3218 * for statically allocated devices, which should all be converted
3219 * some day, we need to initialize the name. We prevent reading back
3220 * the name, and force the use of dev_name()
3222 if (dev->init_name) {
3223 dev_set_name(dev, "%s", dev->init_name);
3224 dev->init_name = NULL;
3227 /* subsystems can specify simple device enumeration */
3228 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
3229 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3231 if (!dev_name(dev)) {
3236 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3238 parent = get_device(dev->parent);
3239 kobj = get_device_parent(dev, parent);
3241 error = PTR_ERR(kobj);
3245 dev->kobj.parent = kobj;
3247 /* use parent numa_node */
3248 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3249 set_dev_node(dev, dev_to_node(parent));
3251 /* first, register with generic layer. */
3252 /* we require the name to be set before, and pass NULL */
3253 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3255 glue_dir = get_glue_dir(dev);
3259 /* notify platform of device entry */
3260 error = device_platform_notify(dev, KOBJ_ADD);
3262 goto platform_error;
3264 error = device_create_file(dev, &dev_attr_uevent);
3268 error = device_add_class_symlinks(dev);
3271 error = device_add_attrs(dev);
3274 error = bus_add_device(dev);
3277 error = dpm_sysfs_add(dev);
3282 if (MAJOR(dev->devt)) {
3283 error = device_create_file(dev, &dev_attr_dev);
3287 error = device_create_sys_dev_entry(dev);
3291 devtmpfs_create_node(dev);
3294 /* Notify clients of device addition. This call must come
3295 * after dpm_sysfs_add() and before kobject_uevent().
3298 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3299 BUS_NOTIFY_ADD_DEVICE, dev);
3301 kobject_uevent(&dev->kobj, KOBJ_ADD);
3304 * Check if any of the other devices (consumers) have been waiting for
3305 * this device (supplier) to be added so that they can create a device
3308 * This needs to happen after device_pm_add() because device_link_add()
3309 * requires the supplier be registered before it's called.
3311 * But this also needs to happen before bus_probe_device() to make sure
3312 * waiting consumers can link to it before the driver is bound to the
3313 * device and the driver sync_state callback is called for this device.
3315 if (dev->fwnode && !dev->fwnode->dev) {
3316 dev->fwnode->dev = dev;
3317 fw_devlink_link_device(dev);
3320 bus_probe_device(dev);
3323 * If all driver registration is done and a newly added device doesn't
3324 * match with any driver, don't block its consumers from probing in
3325 * case the consumer device is able to operate without this supplier.
3327 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3328 fw_devlink_unblock_consumers(dev);
3331 klist_add_tail(&dev->p->knode_parent,
3332 &parent->p->klist_children);
3335 mutex_lock(&dev->class->p->mutex);
3336 /* tie the class to the device */
3337 klist_add_tail(&dev->p->knode_class,
3338 &dev->class->p->klist_devices);
3340 /* notify any interfaces that the device is here */
3341 list_for_each_entry(class_intf,
3342 &dev->class->p->interfaces, node)
3343 if (class_intf->add_dev)
3344 class_intf->add_dev(dev, class_intf);
3345 mutex_unlock(&dev->class->p->mutex);
3351 if (MAJOR(dev->devt))
3352 device_remove_file(dev, &dev_attr_dev);
3354 device_pm_remove(dev);
3355 dpm_sysfs_remove(dev);
3357 bus_remove_device(dev);
3359 device_remove_attrs(dev);
3361 device_remove_class_symlinks(dev);
3363 device_remove_file(dev, &dev_attr_uevent);
3365 device_platform_notify(dev, KOBJ_REMOVE);
3367 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3368 glue_dir = get_glue_dir(dev);
3369 kobject_del(&dev->kobj);
3371 cleanup_glue_dir(dev, glue_dir);
3379 EXPORT_SYMBOL_GPL(device_add);
3382 * device_register - register a device with the system.
3383 * @dev: pointer to the device structure
3385 * This happens in two clean steps - initialize the device
3386 * and add it to the system. The two steps can be called
3387 * separately, but this is the easiest and most common.
3388 * I.e. you should only call the two helpers separately if
3389 * have a clearly defined need to use and refcount the device
3390 * before it is added to the hierarchy.
3392 * For more information, see the kerneldoc for device_initialize()
3395 * NOTE: _Never_ directly free @dev after calling this function, even
3396 * if it returned an error! Always use put_device() to give up the
3397 * reference initialized in this function instead.
3399 int device_register(struct device *dev)
3401 device_initialize(dev);
3402 return device_add(dev);
3404 EXPORT_SYMBOL_GPL(device_register);
3407 * get_device - increment reference count for device.
3410 * This simply forwards the call to kobject_get(), though
3411 * we do take care to provide for the case that we get a NULL
3412 * pointer passed in.
3414 struct device *get_device(struct device *dev)
3416 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3418 EXPORT_SYMBOL_GPL(get_device);
3421 * put_device - decrement reference count.
3422 * @dev: device in question.
3424 void put_device(struct device *dev)
3426 /* might_sleep(); */
3428 kobject_put(&dev->kobj);
3430 EXPORT_SYMBOL_GPL(put_device);
3432 bool kill_device(struct device *dev)
3435 * Require the device lock and set the "dead" flag to guarantee that
3436 * the update behavior is consistent with the other bitfields near
3437 * it and that we cannot have an asynchronous probe routine trying
3438 * to run while we are tearing out the bus/class/sysfs from
3439 * underneath the device.
3441 lockdep_assert_held(&dev->mutex);
3445 dev->p->dead = true;
3448 EXPORT_SYMBOL_GPL(kill_device);
3451 * device_del - delete device from system.
3454 * This is the first part of the device unregistration
3455 * sequence. This removes the device from the lists we control
3456 * from here, has it removed from the other driver model
3457 * subsystems it was added to in device_add(), and removes it
3458 * from the kobject hierarchy.
3460 * NOTE: this should be called manually _iff_ device_add() was
3461 * also called manually.
3463 void device_del(struct device *dev)
3465 struct device *parent = dev->parent;
3466 struct kobject *glue_dir = NULL;
3467 struct class_interface *class_intf;
3468 unsigned int noio_flag;
3474 if (dev->fwnode && dev->fwnode->dev == dev)
3475 dev->fwnode->dev = NULL;
3477 /* Notify clients of device removal. This call must come
3478 * before dpm_sysfs_remove().
3480 noio_flag = memalloc_noio_save();
3482 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3483 BUS_NOTIFY_DEL_DEVICE, dev);
3485 dpm_sysfs_remove(dev);
3487 klist_del(&dev->p->knode_parent);
3488 if (MAJOR(dev->devt)) {
3489 devtmpfs_delete_node(dev);
3490 device_remove_sys_dev_entry(dev);
3491 device_remove_file(dev, &dev_attr_dev);
3494 device_remove_class_symlinks(dev);
3496 mutex_lock(&dev->class->p->mutex);
3497 /* notify any interfaces that the device is now gone */
3498 list_for_each_entry(class_intf,
3499 &dev->class->p->interfaces, node)
3500 if (class_intf->remove_dev)
3501 class_intf->remove_dev(dev, class_intf);
3502 /* remove the device from the class list */
3503 klist_del(&dev->p->knode_class);
3504 mutex_unlock(&dev->class->p->mutex);
3506 device_remove_file(dev, &dev_attr_uevent);
3507 device_remove_attrs(dev);
3508 bus_remove_device(dev);
3509 device_pm_remove(dev);
3510 driver_deferred_probe_del(dev);
3511 device_platform_notify(dev, KOBJ_REMOVE);
3512 device_remove_properties(dev);
3513 device_links_purge(dev);
3516 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3517 BUS_NOTIFY_REMOVED_DEVICE, dev);
3518 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3519 glue_dir = get_glue_dir(dev);
3520 kobject_del(&dev->kobj);
3521 cleanup_glue_dir(dev, glue_dir);
3522 memalloc_noio_restore(noio_flag);
3525 EXPORT_SYMBOL_GPL(device_del);
3528 * device_unregister - unregister device from system.
3529 * @dev: device going away.
3531 * We do this in two parts, like we do device_register(). First,
3532 * we remove it from all the subsystems with device_del(), then
3533 * we decrement the reference count via put_device(). If that
3534 * is the final reference count, the device will be cleaned up
3535 * via device_release() above. Otherwise, the structure will
3536 * stick around until the final reference to the device is dropped.
3538 void device_unregister(struct device *dev)
3540 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3544 EXPORT_SYMBOL_GPL(device_unregister);
3546 static struct device *prev_device(struct klist_iter *i)
3548 struct klist_node *n = klist_prev(i);
3549 struct device *dev = NULL;
3550 struct device_private *p;
3553 p = to_device_private_parent(n);
3559 static struct device *next_device(struct klist_iter *i)
3561 struct klist_node *n = klist_next(i);
3562 struct device *dev = NULL;
3563 struct device_private *p;
3566 p = to_device_private_parent(n);
3573 * device_get_devnode - path of device node file
3575 * @mode: returned file access mode
3576 * @uid: returned file owner
3577 * @gid: returned file group
3578 * @tmp: possibly allocated string
3580 * Return the relative path of a possible device node.
3581 * Non-default names may need to allocate a memory to compose
3582 * a name. This memory is returned in tmp and needs to be
3583 * freed by the caller.
3585 const char *device_get_devnode(struct device *dev,
3586 umode_t *mode, kuid_t *uid, kgid_t *gid,
3593 /* the device type may provide a specific name */
3594 if (dev->type && dev->type->devnode)
3595 *tmp = dev->type->devnode(dev, mode, uid, gid);
3599 /* the class may provide a specific name */
3600 if (dev->class && dev->class->devnode)
3601 *tmp = dev->class->devnode(dev, mode);
3605 /* return name without allocation, tmp == NULL */
3606 if (strchr(dev_name(dev), '!') == NULL)
3607 return dev_name(dev);
3609 /* replace '!' in the name with '/' */
3610 s = kstrdup(dev_name(dev), GFP_KERNEL);
3613 strreplace(s, '!', '/');
3618 * device_for_each_child - device child iterator.
3619 * @parent: parent struct device.
3620 * @fn: function to be called for each device.
3621 * @data: data for the callback.
3623 * Iterate over @parent's child devices, and call @fn for each,
3626 * We check the return of @fn each time. If it returns anything
3627 * other than 0, we break out and return that value.
3629 int device_for_each_child(struct device *parent, void *data,
3630 int (*fn)(struct device *dev, void *data))
3632 struct klist_iter i;
3633 struct device *child;
3639 klist_iter_init(&parent->p->klist_children, &i);
3640 while (!error && (child = next_device(&i)))
3641 error = fn(child, data);
3642 klist_iter_exit(&i);
3645 EXPORT_SYMBOL_GPL(device_for_each_child);
3648 * device_for_each_child_reverse - device child iterator in reversed order.
3649 * @parent: parent struct device.
3650 * @fn: function to be called for each device.
3651 * @data: data for the callback.
3653 * Iterate over @parent's child devices, and call @fn for each,
3656 * We check the return of @fn each time. If it returns anything
3657 * other than 0, we break out and return that value.
3659 int device_for_each_child_reverse(struct device *parent, void *data,
3660 int (*fn)(struct device *dev, void *data))
3662 struct klist_iter i;
3663 struct device *child;
3669 klist_iter_init(&parent->p->klist_children, &i);
3670 while ((child = prev_device(&i)) && !error)
3671 error = fn(child, data);
3672 klist_iter_exit(&i);
3675 EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3678 * device_find_child - device iterator for locating a particular device.
3679 * @parent: parent struct device
3680 * @match: Callback function to check device
3681 * @data: Data to pass to match function
3683 * This is similar to the device_for_each_child() function above, but it
3684 * returns a reference to a device that is 'found' for later use, as
3685 * determined by the @match callback.
3687 * The callback should return 0 if the device doesn't match and non-zero
3688 * if it does. If the callback returns non-zero and a reference to the
3689 * current device can be obtained, this function will return to the caller
3690 * and not iterate over any more devices.
3692 * NOTE: you will need to drop the reference with put_device() after use.
3694 struct device *device_find_child(struct device *parent, void *data,
3695 int (*match)(struct device *dev, void *data))
3697 struct klist_iter i;
3698 struct device *child;
3703 klist_iter_init(&parent->p->klist_children, &i);
3704 while ((child = next_device(&i)))
3705 if (match(child, data) && get_device(child))
3707 klist_iter_exit(&i);
3710 EXPORT_SYMBOL_GPL(device_find_child);
3713 * device_find_child_by_name - device iterator for locating a child device.
3714 * @parent: parent struct device
3715 * @name: name of the child device
3717 * This is similar to the device_find_child() function above, but it
3718 * returns a reference to a device that has the name @name.
3720 * NOTE: you will need to drop the reference with put_device() after use.
3722 struct device *device_find_child_by_name(struct device *parent,
3725 struct klist_iter i;
3726 struct device *child;
3731 klist_iter_init(&parent->p->klist_children, &i);
3732 while ((child = next_device(&i)))
3733 if (sysfs_streq(dev_name(child), name) && get_device(child))
3735 klist_iter_exit(&i);
3738 EXPORT_SYMBOL_GPL(device_find_child_by_name);
3740 int __init devices_init(void)
3742 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3745 dev_kobj = kobject_create_and_add("dev", NULL);
3748 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3749 if (!sysfs_dev_block_kobj)
3750 goto block_kobj_err;
3751 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3752 if (!sysfs_dev_char_kobj)
3758 kobject_put(sysfs_dev_block_kobj);
3760 kobject_put(dev_kobj);
3762 kset_unregister(devices_kset);
3766 static int device_check_offline(struct device *dev, void *not_used)
3770 ret = device_for_each_child(dev, NULL, device_check_offline);
3774 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3778 * device_offline - Prepare the device for hot-removal.
3779 * @dev: Device to be put offline.
3781 * Execute the device bus type's .offline() callback, if present, to prepare
3782 * the device for a subsequent hot-removal. If that succeeds, the device must
3783 * not be used until either it is removed or its bus type's .online() callback
3786 * Call under device_hotplug_lock.
3788 int device_offline(struct device *dev)
3792 if (dev->offline_disabled)
3795 ret = device_for_each_child(dev, NULL, device_check_offline);
3800 if (device_supports_offline(dev)) {
3804 ret = dev->bus->offline(dev);
3806 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3807 dev->offline = true;
3817 * device_online - Put the device back online after successful device_offline().
3818 * @dev: Device to be put back online.
3820 * If device_offline() has been successfully executed for @dev, but the device
3821 * has not been removed subsequently, execute its bus type's .online() callback
3822 * to indicate that the device can be used again.
3824 * Call under device_hotplug_lock.
3826 int device_online(struct device *dev)
3831 if (device_supports_offline(dev)) {
3833 ret = dev->bus->online(dev);
3835 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
3836 dev->offline = false;
3847 struct root_device {
3849 struct module *owner;
3852 static inline struct root_device *to_root_device(struct device *d)
3854 return container_of(d, struct root_device, dev);
3857 static void root_device_release(struct device *dev)
3859 kfree(to_root_device(dev));
3863 * __root_device_register - allocate and register a root device
3864 * @name: root device name
3865 * @owner: owner module of the root device, usually THIS_MODULE
3867 * This function allocates a root device and registers it
3868 * using device_register(). In order to free the returned
3869 * device, use root_device_unregister().
3871 * Root devices are dummy devices which allow other devices
3872 * to be grouped under /sys/devices. Use this function to
3873 * allocate a root device and then use it as the parent of
3874 * any device which should appear under /sys/devices/{name}
3876 * The /sys/devices/{name} directory will also contain a
3877 * 'module' symlink which points to the @owner directory
3880 * Returns &struct device pointer on success, or ERR_PTR() on error.
3882 * Note: You probably want to use root_device_register().
3884 struct device *__root_device_register(const char *name, struct module *owner)
3886 struct root_device *root;
3889 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
3891 return ERR_PTR(err);
3893 err = dev_set_name(&root->dev, "%s", name);
3896 return ERR_PTR(err);
3899 root->dev.release = root_device_release;
3901 err = device_register(&root->dev);
3903 put_device(&root->dev);
3904 return ERR_PTR(err);
3907 #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
3909 struct module_kobject *mk = &owner->mkobj;
3911 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
3913 device_unregister(&root->dev);
3914 return ERR_PTR(err);
3916 root->owner = owner;
3922 EXPORT_SYMBOL_GPL(__root_device_register);
3925 * root_device_unregister - unregister and free a root device
3926 * @dev: device going away
3928 * This function unregisters and cleans up a device that was created by
3929 * root_device_register().
3931 void root_device_unregister(struct device *dev)
3933 struct root_device *root = to_root_device(dev);
3936 sysfs_remove_link(&root->dev.kobj, "module");
3938 device_unregister(dev);
3940 EXPORT_SYMBOL_GPL(root_device_unregister);
3943 static void device_create_release(struct device *dev)
3945 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3949 static __printf(6, 0) struct device *
3950 device_create_groups_vargs(struct class *class, struct device *parent,
3951 dev_t devt, void *drvdata,
3952 const struct attribute_group **groups,
3953 const char *fmt, va_list args)
3955 struct device *dev = NULL;
3956 int retval = -ENODEV;
3958 if (class == NULL || IS_ERR(class))
3961 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3967 device_initialize(dev);
3970 dev->parent = parent;
3971 dev->groups = groups;
3972 dev->release = device_create_release;
3973 dev_set_drvdata(dev, drvdata);
3975 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
3979 retval = device_add(dev);
3987 return ERR_PTR(retval);
3991 * device_create - creates a device and registers it with sysfs
3992 * @class: pointer to the struct class that this device should be registered to
3993 * @parent: pointer to the parent struct device of this new device, if any
3994 * @devt: the dev_t for the char device to be added
3995 * @drvdata: the data to be added to the device for callbacks
3996 * @fmt: string for the device's name
3998 * This function can be used by char device classes. A struct device
3999 * will be created in sysfs, registered to the specified class.
4001 * A "dev" file will be created, showing the dev_t for the device, if
4002 * the dev_t is not 0,0.
4003 * If a pointer to a parent struct device is passed in, the newly created
4004 * struct device will be a child of that device in sysfs.
4005 * The pointer to the struct device will be returned from the call.
4006 * Any further sysfs files that might be required can be created using this
4009 * Returns &struct device pointer on success, or ERR_PTR() on error.
4011 * Note: the struct class passed to this function must have previously
4012 * been created with a call to class_create().
4014 struct device *device_create(struct class *class, struct device *parent,
4015 dev_t devt, void *drvdata, const char *fmt, ...)
4020 va_start(vargs, fmt);
4021 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4026 EXPORT_SYMBOL_GPL(device_create);
4029 * device_create_with_groups - creates a device and registers it with sysfs
4030 * @class: pointer to the struct class that this device should be registered to
4031 * @parent: pointer to the parent struct device of this new device, if any
4032 * @devt: the dev_t for the char device to be added
4033 * @drvdata: the data to be added to the device for callbacks
4034 * @groups: NULL-terminated list of attribute groups to be created
4035 * @fmt: string for the device's name
4037 * This function can be used by char device classes. A struct device
4038 * will be created in sysfs, registered to the specified class.
4039 * Additional attributes specified in the groups parameter will also
4040 * be created automatically.
4042 * A "dev" file will be created, showing the dev_t for the device, if
4043 * the dev_t is not 0,0.
4044 * If a pointer to a parent struct device is passed in, the newly created
4045 * struct device will be a child of that device in sysfs.
4046 * The pointer to the struct device will be returned from the call.
4047 * Any further sysfs files that might be required can be created using this
4050 * Returns &struct device pointer on success, or ERR_PTR() on error.
4052 * Note: the struct class passed to this function must have previously
4053 * been created with a call to class_create().
4055 struct device *device_create_with_groups(struct class *class,
4056 struct device *parent, dev_t devt,
4058 const struct attribute_group **groups,
4059 const char *fmt, ...)
4064 va_start(vargs, fmt);
4065 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4070 EXPORT_SYMBOL_GPL(device_create_with_groups);
4073 * device_destroy - removes a device that was created with device_create()
4074 * @class: pointer to the struct class that this device was registered with
4075 * @devt: the dev_t of the device that was previously registered
4077 * This call unregisters and cleans up a device that was created with a
4078 * call to device_create().
4080 void device_destroy(struct class *class, dev_t devt)
4084 dev = class_find_device_by_devt(class, devt);
4087 device_unregister(dev);
4090 EXPORT_SYMBOL_GPL(device_destroy);
4093 * device_rename - renames a device
4094 * @dev: the pointer to the struct device to be renamed
4095 * @new_name: the new name of the device
4097 * It is the responsibility of the caller to provide mutual
4098 * exclusion between two different calls of device_rename
4099 * on the same device to ensure that new_name is valid and
4100 * won't conflict with other devices.
4102 * Note: Don't call this function. Currently, the networking layer calls this
4103 * function, but that will change. The following text from Kay Sievers offers
4106 * Renaming devices is racy at many levels, symlinks and other stuff are not
4107 * replaced atomically, and you get a "move" uevent, but it's not easy to
4108 * connect the event to the old and new device. Device nodes are not renamed at
4109 * all, there isn't even support for that in the kernel now.
4111 * In the meantime, during renaming, your target name might be taken by another
4112 * driver, creating conflicts. Or the old name is taken directly after you
4113 * renamed it -- then you get events for the same DEVPATH, before you even see
4114 * the "move" event. It's just a mess, and nothing new should ever rely on
4115 * kernel device renaming. Besides that, it's not even implemented now for
4116 * other things than (driver-core wise very simple) network devices.
4118 * We are currently about to change network renaming in udev to completely
4119 * disallow renaming of devices in the same namespace as the kernel uses,
4120 * because we can't solve the problems properly, that arise with swapping names
4121 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
4122 * be allowed to some other name than eth[0-9]*, for the aforementioned
4125 * Make up a "real" name in the driver before you register anything, or add
4126 * some other attributes for userspace to find the device, or use udev to add
4127 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4128 * don't even want to get into that and try to implement the missing pieces in
4129 * the core. We really have other pieces to fix in the driver core mess. :)
4131 int device_rename(struct device *dev, const char *new_name)
4133 struct kobject *kobj = &dev->kobj;
4134 char *old_device_name = NULL;
4137 dev = get_device(dev);
4141 dev_dbg(dev, "renaming to %s\n", new_name);
4143 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4144 if (!old_device_name) {
4150 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
4151 kobj, old_device_name,
4152 new_name, kobject_namespace(kobj));
4157 error = kobject_rename(kobj, new_name);
4164 kfree(old_device_name);
4168 EXPORT_SYMBOL_GPL(device_rename);
4170 static int device_move_class_links(struct device *dev,
4171 struct device *old_parent,
4172 struct device *new_parent)
4177 sysfs_remove_link(&dev->kobj, "device");
4179 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4185 * device_move - moves a device to a new parent
4186 * @dev: the pointer to the struct device to be moved
4187 * @new_parent: the new parent of the device (can be NULL)
4188 * @dpm_order: how to reorder the dpm_list
4190 int device_move(struct device *dev, struct device *new_parent,
4191 enum dpm_order dpm_order)
4194 struct device *old_parent;
4195 struct kobject *new_parent_kobj;
4197 dev = get_device(dev);
4202 new_parent = get_device(new_parent);
4203 new_parent_kobj = get_device_parent(dev, new_parent);
4204 if (IS_ERR(new_parent_kobj)) {
4205 error = PTR_ERR(new_parent_kobj);
4206 put_device(new_parent);
4210 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4211 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4212 error = kobject_move(&dev->kobj, new_parent_kobj);
4214 cleanup_glue_dir(dev, new_parent_kobj);
4215 put_device(new_parent);
4218 old_parent = dev->parent;
4219 dev->parent = new_parent;
4221 klist_remove(&dev->p->knode_parent);
4223 klist_add_tail(&dev->p->knode_parent,
4224 &new_parent->p->klist_children);
4225 set_dev_node(dev, dev_to_node(new_parent));
4229 error = device_move_class_links(dev, old_parent, new_parent);
4231 /* We ignore errors on cleanup since we're hosed anyway... */
4232 device_move_class_links(dev, new_parent, old_parent);
4233 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4235 klist_remove(&dev->p->knode_parent);
4236 dev->parent = old_parent;
4238 klist_add_tail(&dev->p->knode_parent,
4239 &old_parent->p->klist_children);
4240 set_dev_node(dev, dev_to_node(old_parent));
4243 cleanup_glue_dir(dev, new_parent_kobj);
4244 put_device(new_parent);
4248 switch (dpm_order) {
4249 case DPM_ORDER_NONE:
4251 case DPM_ORDER_DEV_AFTER_PARENT:
4252 device_pm_move_after(dev, new_parent);
4253 devices_kset_move_after(dev, new_parent);
4255 case DPM_ORDER_PARENT_BEFORE_DEV:
4256 device_pm_move_before(new_parent, dev);
4257 devices_kset_move_before(new_parent, dev);
4259 case DPM_ORDER_DEV_LAST:
4260 device_pm_move_last(dev);
4261 devices_kset_move_last(dev);
4265 put_device(old_parent);
4271 EXPORT_SYMBOL_GPL(device_move);
4273 static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4276 struct kobject *kobj = &dev->kobj;
4277 struct class *class = dev->class;
4278 const struct device_type *type = dev->type;
4283 * Change the device groups of the device class for @dev to
4286 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4294 * Change the device groups of the device type for @dev to
4297 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4303 /* Change the device groups of @dev to @kuid/@kgid. */
4304 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4308 if (device_supports_offline(dev) && !dev->offline_disabled) {
4309 /* Change online device attributes of @dev to @kuid/@kgid. */
4310 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4320 * device_change_owner - change the owner of an existing device.
4322 * @kuid: new owner's kuid
4323 * @kgid: new owner's kgid
4325 * This changes the owner of @dev and its corresponding sysfs entries to
4326 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4329 * Returns 0 on success or error code on failure.
4331 int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4334 struct kobject *kobj = &dev->kobj;
4336 dev = get_device(dev);
4341 * Change the kobject and the default attributes and groups of the
4342 * ktype associated with it to @kuid/@kgid.
4344 error = sysfs_change_owner(kobj, kuid, kgid);
4349 * Change the uevent file for @dev to the new owner. The uevent file
4350 * was created in a separate step when @dev got added and we mirror
4353 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4359 * Change the device groups, the device groups associated with the
4360 * device class, and the groups associated with the device type of @dev
4363 error = device_attrs_change_owner(dev, kuid, kgid);
4367 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4372 if (sysfs_deprecated && dev->class == &block_class)
4377 * Change the owner of the symlink located in the class directory of
4378 * the device class associated with @dev which points to the actual
4379 * directory entry for @dev to @kuid/@kgid. This ensures that the
4380 * symlink shows the same permissions as its target.
4382 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
4383 dev_name(dev), kuid, kgid);
4391 EXPORT_SYMBOL_GPL(device_change_owner);
4394 * device_shutdown - call ->shutdown() on each device to shutdown.
4396 void device_shutdown(void)
4398 struct device *dev, *parent;
4400 wait_for_device_probe();
4401 device_block_probing();
4405 spin_lock(&devices_kset->list_lock);
4407 * Walk the devices list backward, shutting down each in turn.
4408 * Beware that device unplug events may also start pulling
4409 * devices offline, even as the system is shutting down.
4411 while (!list_empty(&devices_kset->list)) {
4412 dev = list_entry(devices_kset->list.prev, struct device,
4416 * hold reference count of device's parent to
4417 * prevent it from being freed because parent's
4418 * lock is to be held
4420 parent = get_device(dev->parent);
4423 * Make sure the device is off the kset list, in the
4424 * event that dev->*->shutdown() doesn't remove it.
4426 list_del_init(&dev->kobj.entry);
4427 spin_unlock(&devices_kset->list_lock);
4429 /* hold lock to avoid race with probe/release */
4431 device_lock(parent);
4434 /* Don't allow any more runtime suspends */
4435 pm_runtime_get_noresume(dev);
4436 pm_runtime_barrier(dev);
4438 if (dev->class && dev->class->shutdown_pre) {
4440 dev_info(dev, "shutdown_pre\n");
4441 dev->class->shutdown_pre(dev);
4443 if (dev->bus && dev->bus->shutdown) {
4445 dev_info(dev, "shutdown\n");
4446 dev->bus->shutdown(dev);
4447 } else if (dev->driver && dev->driver->shutdown) {
4449 dev_info(dev, "shutdown\n");
4450 dev->driver->shutdown(dev);
4455 device_unlock(parent);
4460 spin_lock(&devices_kset->list_lock);
4462 spin_unlock(&devices_kset->list_lock);
4466 * Device logging functions
4469 #ifdef CONFIG_PRINTK
4471 set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4475 memset(dev_info, 0, sizeof(*dev_info));
4478 subsys = dev->class->name;
4480 subsys = dev->bus->name;
4484 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4487 * Add device identifier DEVICE=:
4491 * +sound:card0 subsystem:devname
4493 if (MAJOR(dev->devt)) {
4496 if (strcmp(subsys, "block") == 0)
4501 snprintf(dev_info->device, sizeof(dev_info->device),
4502 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4503 } else if (strcmp(subsys, "net") == 0) {
4504 struct net_device *net = to_net_dev(dev);
4506 snprintf(dev_info->device, sizeof(dev_info->device),
4507 "n%u", net->ifindex);
4509 snprintf(dev_info->device, sizeof(dev_info->device),
4510 "+%s:%s", subsys, dev_name(dev));
4514 int dev_vprintk_emit(int level, const struct device *dev,
4515 const char *fmt, va_list args)
4517 struct dev_printk_info dev_info;
4519 set_dev_info(dev, &dev_info);
4521 return vprintk_emit(0, level, &dev_info, fmt, args);
4523 EXPORT_SYMBOL(dev_vprintk_emit);
4525 int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4530 va_start(args, fmt);
4532 r = dev_vprintk_emit(level, dev, fmt, args);
4538 EXPORT_SYMBOL(dev_printk_emit);
4540 static void __dev_printk(const char *level, const struct device *dev,
4541 struct va_format *vaf)
4544 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4545 dev_driver_string(dev), dev_name(dev), vaf);
4547 printk("%s(NULL device *): %pV", level, vaf);
4550 void dev_printk(const char *level, const struct device *dev,
4551 const char *fmt, ...)
4553 struct va_format vaf;
4556 va_start(args, fmt);
4561 __dev_printk(level, dev, &vaf);
4565 EXPORT_SYMBOL(dev_printk);
4567 #define define_dev_printk_level(func, kern_level) \
4568 void func(const struct device *dev, const char *fmt, ...) \
4570 struct va_format vaf; \
4573 va_start(args, fmt); \
4578 __dev_printk(kern_level, dev, &vaf); \
4582 EXPORT_SYMBOL(func);
4584 define_dev_printk_level(_dev_emerg, KERN_EMERG);
4585 define_dev_printk_level(_dev_alert, KERN_ALERT);
4586 define_dev_printk_level(_dev_crit, KERN_CRIT);
4587 define_dev_printk_level(_dev_err, KERN_ERR);
4588 define_dev_printk_level(_dev_warn, KERN_WARNING);
4589 define_dev_printk_level(_dev_notice, KERN_NOTICE);
4590 define_dev_printk_level(_dev_info, KERN_INFO);
4595 * dev_err_probe - probe error check and log helper
4596 * @dev: the pointer to the struct device
4597 * @err: error value to test
4598 * @fmt: printf-style format string
4599 * @...: arguments as specified in the format string
4601 * This helper implements common pattern present in probe functions for error
4602 * checking: print debug or error message depending if the error value is
4603 * -EPROBE_DEFER and propagate error upwards.
4604 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4605 * checked later by reading devices_deferred debugfs attribute.
4606 * It replaces code sequence::
4608 * if (err != -EPROBE_DEFER)
4609 * dev_err(dev, ...);
4611 * dev_dbg(dev, ...);
4616 * return dev_err_probe(dev, err, ...);
4621 int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4623 struct va_format vaf;
4626 va_start(args, fmt);
4630 if (err != -EPROBE_DEFER) {
4631 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4633 device_set_deferred_probe_reason(dev, &vaf);
4634 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4641 EXPORT_SYMBOL_GPL(dev_err_probe);
4643 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4645 return fwnode && !IS_ERR(fwnode->secondary);
4649 * set_primary_fwnode - Change the primary firmware node of a given device.
4650 * @dev: Device to handle.
4651 * @fwnode: New primary firmware node of the device.
4653 * Set the device's firmware node pointer to @fwnode, but if a secondary
4654 * firmware node of the device is present, preserve it.
4656 * Valid fwnode cases are:
4657 * - primary --> secondary --> -ENODEV
4658 * - primary --> NULL
4659 * - secondary --> -ENODEV
4662 void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4664 struct device *parent = dev->parent;
4665 struct fwnode_handle *fn = dev->fwnode;
4668 if (fwnode_is_primary(fn))
4672 WARN_ON(fwnode->secondary);
4673 fwnode->secondary = fn;
4675 dev->fwnode = fwnode;
4677 if (fwnode_is_primary(fn)) {
4678 dev->fwnode = fn->secondary;
4679 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
4680 if (!(parent && fn == parent->fwnode))
4681 fn->secondary = NULL;
4687 EXPORT_SYMBOL_GPL(set_primary_fwnode);
4690 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4691 * @dev: Device to handle.
4692 * @fwnode: New secondary firmware node of the device.
4694 * If a primary firmware node of the device is present, set its secondary
4695 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4698 void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4701 fwnode->secondary = ERR_PTR(-ENODEV);
4703 if (fwnode_is_primary(dev->fwnode))
4704 dev->fwnode->secondary = fwnode;
4706 dev->fwnode = fwnode;
4708 EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4711 * device_set_of_node_from_dev - reuse device-tree node of another device
4712 * @dev: device whose device-tree node is being set
4713 * @dev2: device whose device-tree node is being reused
4715 * Takes another reference to the new device-tree node after first dropping
4716 * any reference held to the old node.
4718 void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4720 of_node_put(dev->of_node);
4721 dev->of_node = of_node_get(dev2->of_node);
4722 dev->of_node_reused = true;
4724 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4726 int device_match_name(struct device *dev, const void *name)
4728 return sysfs_streq(dev_name(dev), name);
4730 EXPORT_SYMBOL_GPL(device_match_name);
4732 int device_match_of_node(struct device *dev, const void *np)
4734 return dev->of_node == np;
4736 EXPORT_SYMBOL_GPL(device_match_of_node);
4738 int device_match_fwnode(struct device *dev, const void *fwnode)
4740 return dev_fwnode(dev) == fwnode;
4742 EXPORT_SYMBOL_GPL(device_match_fwnode);
4744 int device_match_devt(struct device *dev, const void *pdevt)
4746 return dev->devt == *(dev_t *)pdevt;
4748 EXPORT_SYMBOL_GPL(device_match_devt);
4750 int device_match_acpi_dev(struct device *dev, const void *adev)
4752 return ACPI_COMPANION(dev) == adev;
4754 EXPORT_SYMBOL(device_match_acpi_dev);
4756 int device_match_any(struct device *dev, const void *unused)
4760 EXPORT_SYMBOL_GPL(device_match_any);