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/swiotlb.h>
31 #include <linux/sysfs.h>
32 #include <linux/dma-map-ops.h> /* for dma_default_coherent */
35 #include "power/power.h"
37 #ifdef CONFIG_SYSFS_DEPRECATED
38 #ifdef CONFIG_SYSFS_DEPRECATED_V2
39 long sysfs_deprecated = 1;
41 long sysfs_deprecated = 0;
43 static int __init sysfs_deprecated_setup(char *arg)
45 return kstrtol(arg, 10, &sysfs_deprecated);
47 early_param("sysfs.deprecated", sysfs_deprecated_setup);
50 /* Device links support. */
51 static LIST_HEAD(deferred_sync);
52 static unsigned int defer_sync_state_count = 1;
53 static DEFINE_MUTEX(fwnode_link_lock);
54 static bool fw_devlink_is_permissive(void);
55 static bool fw_devlink_drv_reg_done;
58 * fwnode_link_add - Create a link between two fwnode_handles.
59 * @con: Consumer end of the link.
60 * @sup: Supplier end of the link.
62 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
63 * represents the detail that the firmware lists @sup fwnode as supplying a
66 * The driver core will use the fwnode link to create a device link between the
67 * two device objects corresponding to @con and @sup when they are created. The
68 * driver core will automatically delete the fwnode link between @con and @sup
71 * Attempts to create duplicate links between the same pair of fwnode handles
72 * are ignored and there is no reference counting.
74 int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
76 struct fwnode_link *link;
79 mutex_lock(&fwnode_link_lock);
81 list_for_each_entry(link, &sup->consumers, s_hook)
82 if (link->consumer == con)
85 link = kzalloc(sizeof(*link), GFP_KERNEL);
92 INIT_LIST_HEAD(&link->s_hook);
94 INIT_LIST_HEAD(&link->c_hook);
96 list_add(&link->s_hook, &sup->consumers);
97 list_add(&link->c_hook, &con->suppliers);
99 mutex_unlock(&fwnode_link_lock);
105 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
106 * @fwnode: fwnode whose supplier links need to be deleted
108 * Deletes all supplier links connecting directly to @fwnode.
110 static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
112 struct fwnode_link *link, *tmp;
114 mutex_lock(&fwnode_link_lock);
115 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
116 list_del(&link->s_hook);
117 list_del(&link->c_hook);
120 mutex_unlock(&fwnode_link_lock);
124 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
125 * @fwnode: fwnode whose consumer links need to be deleted
127 * Deletes all consumer links connecting directly to @fwnode.
129 static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
131 struct fwnode_link *link, *tmp;
133 mutex_lock(&fwnode_link_lock);
134 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
135 list_del(&link->s_hook);
136 list_del(&link->c_hook);
139 mutex_unlock(&fwnode_link_lock);
143 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
144 * @fwnode: fwnode whose links needs to be deleted
146 * Deletes all links connecting directly to a fwnode.
148 void fwnode_links_purge(struct fwnode_handle *fwnode)
150 fwnode_links_purge_suppliers(fwnode);
151 fwnode_links_purge_consumers(fwnode);
154 void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
156 struct fwnode_handle *child;
158 /* Don't purge consumer links of an added child */
162 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
163 fwnode_links_purge_consumers(fwnode);
165 fwnode_for_each_available_child_node(fwnode, child)
166 fw_devlink_purge_absent_suppliers(child);
168 EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
171 static DEFINE_MUTEX(device_links_lock);
172 DEFINE_STATIC_SRCU(device_links_srcu);
174 static inline void device_links_write_lock(void)
176 mutex_lock(&device_links_lock);
179 static inline void device_links_write_unlock(void)
181 mutex_unlock(&device_links_lock);
184 int device_links_read_lock(void) __acquires(&device_links_srcu)
186 return srcu_read_lock(&device_links_srcu);
189 void device_links_read_unlock(int idx) __releases(&device_links_srcu)
191 srcu_read_unlock(&device_links_srcu, idx);
194 int device_links_read_lock_held(void)
196 return srcu_read_lock_held(&device_links_srcu);
199 static void device_link_synchronize_removal(void)
201 synchronize_srcu(&device_links_srcu);
204 static void device_link_remove_from_lists(struct device_link *link)
206 list_del_rcu(&link->s_node);
207 list_del_rcu(&link->c_node);
209 #else /* !CONFIG_SRCU */
210 static DECLARE_RWSEM(device_links_lock);
212 static inline void device_links_write_lock(void)
214 down_write(&device_links_lock);
217 static inline void device_links_write_unlock(void)
219 up_write(&device_links_lock);
222 int device_links_read_lock(void)
224 down_read(&device_links_lock);
228 void device_links_read_unlock(int not_used)
230 up_read(&device_links_lock);
233 #ifdef CONFIG_DEBUG_LOCK_ALLOC
234 int device_links_read_lock_held(void)
236 return lockdep_is_held(&device_links_lock);
240 static inline void device_link_synchronize_removal(void)
244 static void device_link_remove_from_lists(struct device_link *link)
246 list_del(&link->s_node);
247 list_del(&link->c_node);
249 #endif /* !CONFIG_SRCU */
251 static bool device_is_ancestor(struct device *dev, struct device *target)
253 while (target->parent) {
254 target = target->parent;
262 * device_is_dependent - Check if one device depends on another one
263 * @dev: Device to check dependencies for.
264 * @target: Device to check against.
266 * Check if @target depends on @dev or any device dependent on it (its child or
267 * its consumer etc). Return 1 if that is the case or 0 otherwise.
269 int device_is_dependent(struct device *dev, void *target)
271 struct device_link *link;
275 * The "ancestors" check is needed to catch the case when the target
276 * device has not been completely initialized yet and it is still
277 * missing from the list of children of its parent device.
279 if (dev == target || device_is_ancestor(dev, target))
282 ret = device_for_each_child(dev, target, device_is_dependent);
286 list_for_each_entry(link, &dev->links.consumers, s_node) {
287 if ((link->flags & ~DL_FLAG_INFERRED) ==
288 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
291 if (link->consumer == target)
294 ret = device_is_dependent(link->consumer, target);
301 static void device_link_init_status(struct device_link *link,
302 struct device *consumer,
303 struct device *supplier)
305 switch (supplier->links.status) {
307 switch (consumer->links.status) {
310 * A consumer driver can create a link to a supplier
311 * that has not completed its probing yet as long as it
312 * knows that the supplier is already functional (for
313 * example, it has just acquired some resources from the
316 link->status = DL_STATE_CONSUMER_PROBE;
319 link->status = DL_STATE_DORMANT;
323 case DL_DEV_DRIVER_BOUND:
324 switch (consumer->links.status) {
326 link->status = DL_STATE_CONSUMER_PROBE;
328 case DL_DEV_DRIVER_BOUND:
329 link->status = DL_STATE_ACTIVE;
332 link->status = DL_STATE_AVAILABLE;
336 case DL_DEV_UNBINDING:
337 link->status = DL_STATE_SUPPLIER_UNBIND;
340 link->status = DL_STATE_DORMANT;
345 static int device_reorder_to_tail(struct device *dev, void *not_used)
347 struct device_link *link;
350 * Devices that have not been registered yet will be put to the ends
351 * of the lists during the registration, so skip them here.
353 if (device_is_registered(dev))
354 devices_kset_move_last(dev);
356 if (device_pm_initialized(dev))
357 device_pm_move_last(dev);
359 device_for_each_child(dev, NULL, device_reorder_to_tail);
360 list_for_each_entry(link, &dev->links.consumers, s_node) {
361 if ((link->flags & ~DL_FLAG_INFERRED) ==
362 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
364 device_reorder_to_tail(link->consumer, NULL);
371 * device_pm_move_to_tail - Move set of devices to the end of device lists
372 * @dev: Device to move
374 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
376 * It moves the @dev along with all of its children and all of its consumers
377 * to the ends of the device_kset and dpm_list, recursively.
379 void device_pm_move_to_tail(struct device *dev)
383 idx = device_links_read_lock();
385 device_reorder_to_tail(dev, NULL);
387 device_links_read_unlock(idx);
390 #define to_devlink(dev) container_of((dev), struct device_link, link_dev)
392 static ssize_t status_show(struct device *dev,
393 struct device_attribute *attr, char *buf)
397 switch (to_devlink(dev)->status) {
399 output = "not tracked";
401 case DL_STATE_DORMANT:
404 case DL_STATE_AVAILABLE:
405 output = "available";
407 case DL_STATE_CONSUMER_PROBE:
408 output = "consumer probing";
410 case DL_STATE_ACTIVE:
413 case DL_STATE_SUPPLIER_UNBIND:
414 output = "supplier unbinding";
421 return sysfs_emit(buf, "%s\n", output);
423 static DEVICE_ATTR_RO(status);
425 static ssize_t auto_remove_on_show(struct device *dev,
426 struct device_attribute *attr, char *buf)
428 struct device_link *link = to_devlink(dev);
431 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
432 output = "supplier unbind";
433 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
434 output = "consumer unbind";
438 return sysfs_emit(buf, "%s\n", output);
440 static DEVICE_ATTR_RO(auto_remove_on);
442 static ssize_t runtime_pm_show(struct device *dev,
443 struct device_attribute *attr, char *buf)
445 struct device_link *link = to_devlink(dev);
447 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
449 static DEVICE_ATTR_RO(runtime_pm);
451 static ssize_t sync_state_only_show(struct device *dev,
452 struct device_attribute *attr, char *buf)
454 struct device_link *link = to_devlink(dev);
456 return sysfs_emit(buf, "%d\n",
457 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
459 static DEVICE_ATTR_RO(sync_state_only);
461 static struct attribute *devlink_attrs[] = {
462 &dev_attr_status.attr,
463 &dev_attr_auto_remove_on.attr,
464 &dev_attr_runtime_pm.attr,
465 &dev_attr_sync_state_only.attr,
468 ATTRIBUTE_GROUPS(devlink);
470 static void device_link_release_fn(struct work_struct *work)
472 struct device_link *link = container_of(work, struct device_link, rm_work);
474 /* Ensure that all references to the link object have been dropped. */
475 device_link_synchronize_removal();
477 while (refcount_dec_not_one(&link->rpm_active))
478 pm_runtime_put(link->supplier);
480 put_device(link->consumer);
481 put_device(link->supplier);
485 static void devlink_dev_release(struct device *dev)
487 struct device_link *link = to_devlink(dev);
489 INIT_WORK(&link->rm_work, device_link_release_fn);
491 * It may take a while to complete this work because of the SRCU
492 * synchronization in device_link_release_fn() and if the consumer or
493 * supplier devices get deleted when it runs, so put it into the "long"
496 queue_work(system_long_wq, &link->rm_work);
499 static struct class devlink_class = {
501 .owner = THIS_MODULE,
502 .dev_groups = devlink_groups,
503 .dev_release = devlink_dev_release,
506 static int devlink_add_symlinks(struct device *dev,
507 struct class_interface *class_intf)
511 struct device_link *link = to_devlink(dev);
512 struct device *sup = link->supplier;
513 struct device *con = link->consumer;
516 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
517 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
519 len += strlen("supplier:") + 1;
520 buf = kzalloc(len, GFP_KERNEL);
524 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
528 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
532 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
533 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
537 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
538 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
545 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
546 sysfs_remove_link(&sup->kobj, buf);
548 sysfs_remove_link(&link->link_dev.kobj, "consumer");
550 sysfs_remove_link(&link->link_dev.kobj, "supplier");
556 static void devlink_remove_symlinks(struct device *dev,
557 struct class_interface *class_intf)
559 struct device_link *link = to_devlink(dev);
561 struct device *sup = link->supplier;
562 struct device *con = link->consumer;
565 sysfs_remove_link(&link->link_dev.kobj, "consumer");
566 sysfs_remove_link(&link->link_dev.kobj, "supplier");
568 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
569 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
571 len += strlen("supplier:") + 1;
572 buf = kzalloc(len, GFP_KERNEL);
574 WARN(1, "Unable to properly free device link symlinks!\n");
578 if (device_is_registered(con)) {
579 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
580 sysfs_remove_link(&con->kobj, buf);
582 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
583 sysfs_remove_link(&sup->kobj, buf);
587 static struct class_interface devlink_class_intf = {
588 .class = &devlink_class,
589 .add_dev = devlink_add_symlinks,
590 .remove_dev = devlink_remove_symlinks,
593 static int __init devlink_class_init(void)
597 ret = class_register(&devlink_class);
601 ret = class_interface_register(&devlink_class_intf);
603 class_unregister(&devlink_class);
607 postcore_initcall(devlink_class_init);
609 #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
610 DL_FLAG_AUTOREMOVE_SUPPLIER | \
611 DL_FLAG_AUTOPROBE_CONSUMER | \
612 DL_FLAG_SYNC_STATE_ONLY | \
615 #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
616 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
619 * device_link_add - Create a link between two devices.
620 * @consumer: Consumer end of the link.
621 * @supplier: Supplier end of the link.
622 * @flags: Link flags.
624 * The caller is responsible for the proper synchronization of the link creation
625 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
626 * runtime PM framework to take the link into account. Second, if the
627 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
628 * be forced into the active meta state and reference-counted upon the creation
629 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
632 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
633 * expected to release the link returned by it directly with the help of either
634 * device_link_del() or device_link_remove().
636 * If that flag is not set, however, the caller of this function is handing the
637 * management of the link over to the driver core entirely and its return value
638 * can only be used to check whether or not the link is present. In that case,
639 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
640 * flags can be used to indicate to the driver core when the link can be safely
641 * deleted. Namely, setting one of them in @flags indicates to the driver core
642 * that the link is not going to be used (by the given caller of this function)
643 * after unbinding the consumer or supplier driver, respectively, from its
644 * device, so the link can be deleted at that point. If none of them is set,
645 * the link will be maintained until one of the devices pointed to by it (either
646 * the consumer or the supplier) is unregistered.
648 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
649 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
650 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
651 * be used to request the driver core to automatically probe for a consumer
652 * driver after successfully binding a driver to the supplier device.
654 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
655 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
656 * the same time is invalid and will cause NULL to be returned upfront.
657 * However, if a device link between the given @consumer and @supplier pair
658 * exists already when this function is called for them, the existing link will
659 * be returned regardless of its current type and status (the link's flags may
660 * be modified then). The caller of this function is then expected to treat
661 * the link as though it has just been created, so (in particular) if
662 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
663 * explicitly when not needed any more (as stated above).
665 * A side effect of the link creation is re-ordering of dpm_list and the
666 * devices_kset list by moving the consumer device and all devices depending
667 * on it to the ends of these lists (that does not happen to devices that have
668 * not been registered when this function is called).
670 * The supplier device is required to be registered when this function is called
671 * and NULL will be returned if that is not the case. The consumer device need
672 * not be registered, however.
674 struct device_link *device_link_add(struct device *consumer,
675 struct device *supplier, u32 flags)
677 struct device_link *link;
679 if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS ||
680 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
681 (flags & DL_FLAG_SYNC_STATE_ONLY &&
682 (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) ||
683 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
684 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
685 DL_FLAG_AUTOREMOVE_SUPPLIER)))
688 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
689 if (pm_runtime_get_sync(supplier) < 0) {
690 pm_runtime_put_noidle(supplier);
695 if (!(flags & DL_FLAG_STATELESS))
696 flags |= DL_FLAG_MANAGED;
698 device_links_write_lock();
702 * If the supplier has not been fully registered yet or there is a
703 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
704 * the supplier already in the graph, return NULL. If the link is a
705 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
706 * because it only affects sync_state() callbacks.
708 if (!device_pm_initialized(supplier)
709 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
710 device_is_dependent(consumer, supplier))) {
716 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
717 * So, only create it if the consumer hasn't probed yet.
719 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
720 consumer->links.status != DL_DEV_NO_DRIVER &&
721 consumer->links.status != DL_DEV_PROBING) {
727 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
728 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
729 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
731 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
732 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
734 list_for_each_entry(link, &supplier->links.consumers, s_node) {
735 if (link->consumer != consumer)
738 if (link->flags & DL_FLAG_INFERRED &&
739 !(flags & DL_FLAG_INFERRED))
740 link->flags &= ~DL_FLAG_INFERRED;
742 if (flags & DL_FLAG_PM_RUNTIME) {
743 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
744 pm_runtime_new_link(consumer);
745 link->flags |= DL_FLAG_PM_RUNTIME;
747 if (flags & DL_FLAG_RPM_ACTIVE)
748 refcount_inc(&link->rpm_active);
751 if (flags & DL_FLAG_STATELESS) {
752 kref_get(&link->kref);
753 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
754 !(link->flags & DL_FLAG_STATELESS)) {
755 link->flags |= DL_FLAG_STATELESS;
758 link->flags |= DL_FLAG_STATELESS;
764 * If the life time of the link following from the new flags is
765 * longer than indicated by the flags of the existing link,
766 * update the existing link to stay around longer.
768 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
769 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
770 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
771 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
773 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
774 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
775 DL_FLAG_AUTOREMOVE_SUPPLIER);
777 if (!(link->flags & DL_FLAG_MANAGED)) {
778 kref_get(&link->kref);
779 link->flags |= DL_FLAG_MANAGED;
780 device_link_init_status(link, consumer, supplier);
782 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
783 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
784 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
791 link = kzalloc(sizeof(*link), GFP_KERNEL);
795 refcount_set(&link->rpm_active, 1);
797 get_device(supplier);
798 link->supplier = supplier;
799 INIT_LIST_HEAD(&link->s_node);
800 get_device(consumer);
801 link->consumer = consumer;
802 INIT_LIST_HEAD(&link->c_node);
804 kref_init(&link->kref);
806 link->link_dev.class = &devlink_class;
807 device_set_pm_not_required(&link->link_dev);
808 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
809 dev_bus_name(supplier), dev_name(supplier),
810 dev_bus_name(consumer), dev_name(consumer));
811 if (device_register(&link->link_dev)) {
812 put_device(consumer);
813 put_device(supplier);
819 if (flags & DL_FLAG_PM_RUNTIME) {
820 if (flags & DL_FLAG_RPM_ACTIVE)
821 refcount_inc(&link->rpm_active);
823 pm_runtime_new_link(consumer);
826 /* Determine the initial link state. */
827 if (flags & DL_FLAG_STATELESS)
828 link->status = DL_STATE_NONE;
830 device_link_init_status(link, consumer, supplier);
833 * Some callers expect the link creation during consumer driver probe to
834 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
836 if (link->status == DL_STATE_CONSUMER_PROBE &&
837 flags & DL_FLAG_PM_RUNTIME)
838 pm_runtime_resume(supplier);
840 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
841 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
843 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
845 "Linked as a sync state only consumer to %s\n",
852 * Move the consumer and all of the devices depending on it to the end
853 * of dpm_list and the devices_kset list.
855 * It is necessary to hold dpm_list locked throughout all that or else
856 * we may end up suspending with a wrong ordering of it.
858 device_reorder_to_tail(consumer, NULL);
860 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
864 device_links_write_unlock();
866 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
867 pm_runtime_put(supplier);
871 EXPORT_SYMBOL_GPL(device_link_add);
873 static void __device_link_del(struct kref *kref)
875 struct device_link *link = container_of(kref, struct device_link, kref);
877 dev_dbg(link->consumer, "Dropping the link to %s\n",
878 dev_name(link->supplier));
880 pm_runtime_drop_link(link);
882 device_link_remove_from_lists(link);
883 device_unregister(&link->link_dev);
886 static void device_link_put_kref(struct device_link *link)
888 if (link->flags & DL_FLAG_STATELESS)
889 kref_put(&link->kref, __device_link_del);
890 else if (!device_is_registered(link->consumer))
891 __device_link_del(&link->kref);
893 WARN(1, "Unable to drop a managed device link reference\n");
897 * device_link_del - Delete a stateless link between two devices.
898 * @link: Device link to delete.
900 * The caller must ensure proper synchronization of this function with runtime
901 * PM. If the link was added multiple times, it needs to be deleted as often.
902 * Care is required for hotplugged devices: Their links are purged on removal
903 * and calling device_link_del() is then no longer allowed.
905 void device_link_del(struct device_link *link)
907 device_links_write_lock();
908 device_link_put_kref(link);
909 device_links_write_unlock();
911 EXPORT_SYMBOL_GPL(device_link_del);
914 * device_link_remove - Delete a stateless link between two devices.
915 * @consumer: Consumer end of the link.
916 * @supplier: Supplier end of the link.
918 * The caller must ensure proper synchronization of this function with runtime
921 void device_link_remove(void *consumer, struct device *supplier)
923 struct device_link *link;
925 if (WARN_ON(consumer == supplier))
928 device_links_write_lock();
930 list_for_each_entry(link, &supplier->links.consumers, s_node) {
931 if (link->consumer == consumer) {
932 device_link_put_kref(link);
937 device_links_write_unlock();
939 EXPORT_SYMBOL_GPL(device_link_remove);
941 static void device_links_missing_supplier(struct device *dev)
943 struct device_link *link;
945 list_for_each_entry(link, &dev->links.suppliers, c_node) {
946 if (link->status != DL_STATE_CONSUMER_PROBE)
949 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
950 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
952 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
953 WRITE_ONCE(link->status, DL_STATE_DORMANT);
959 * device_links_check_suppliers - Check presence of supplier drivers.
960 * @dev: Consumer device.
962 * Check links from this device to any suppliers. Walk the list of the device's
963 * links to suppliers and see if all of them are available. If not, simply
964 * return -EPROBE_DEFER.
966 * We need to guarantee that the supplier will not go away after the check has
967 * been positive here. It only can go away in __device_release_driver() and
968 * that function checks the device's links to consumers. This means we need to
969 * mark the link as "consumer probe in progress" to make the supplier removal
970 * wait for us to complete (or bad things may happen).
972 * Links without the DL_FLAG_MANAGED flag set are ignored.
974 int device_links_check_suppliers(struct device *dev)
976 struct device_link *link;
980 * Device waiting for supplier to become available is not allowed to
983 mutex_lock(&fwnode_link_lock);
984 if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
985 !fw_devlink_is_permissive()) {
986 dev_dbg(dev, "probe deferral - wait for supplier %pfwP\n",
987 list_first_entry(&dev->fwnode->suppliers,
990 mutex_unlock(&fwnode_link_lock);
991 return -EPROBE_DEFER;
993 mutex_unlock(&fwnode_link_lock);
995 device_links_write_lock();
997 list_for_each_entry(link, &dev->links.suppliers, c_node) {
998 if (!(link->flags & DL_FLAG_MANAGED))
1001 if (link->status != DL_STATE_AVAILABLE &&
1002 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1003 device_links_missing_supplier(dev);
1004 dev_dbg(dev, "probe deferral - supplier %s not ready\n",
1005 dev_name(link->supplier));
1006 ret = -EPROBE_DEFER;
1009 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1011 dev->links.status = DL_DEV_PROBING;
1013 device_links_write_unlock();
1018 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1019 * @dev: Device to call sync_state() on
1020 * @list: List head to queue the @dev on
1022 * Queues a device for a sync_state() callback when the device links write lock
1023 * isn't held. This allows the sync_state() execution flow to use device links
1024 * APIs. The caller must ensure this function is called with
1025 * device_links_write_lock() held.
1027 * This function does a get_device() to make sure the device is not freed while
1030 * So the caller must also ensure that device_links_flush_sync_list() is called
1031 * as soon as the caller releases device_links_write_lock(). This is necessary
1032 * to make sure the sync_state() is called in a timely fashion and the
1033 * put_device() is called on this device.
1035 static void __device_links_queue_sync_state(struct device *dev,
1036 struct list_head *list)
1038 struct device_link *link;
1040 if (!dev_has_sync_state(dev))
1042 if (dev->state_synced)
1045 list_for_each_entry(link, &dev->links.consumers, s_node) {
1046 if (!(link->flags & DL_FLAG_MANAGED))
1048 if (link->status != DL_STATE_ACTIVE)
1053 * Set the flag here to avoid adding the same device to a list more
1054 * than once. This can happen if new consumers get added to the device
1055 * and probed before the list is flushed.
1057 dev->state_synced = true;
1059 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1063 list_add_tail(&dev->links.defer_sync, list);
1067 * device_links_flush_sync_list - Call sync_state() on a list of devices
1068 * @list: List of devices to call sync_state() on
1069 * @dont_lock_dev: Device for which lock is already held by the caller
1071 * Calls sync_state() on all the devices that have been queued for it. This
1072 * function is used in conjunction with __device_links_queue_sync_state(). The
1073 * @dont_lock_dev parameter is useful when this function is called from a
1074 * context where a device lock is already held.
1076 static void device_links_flush_sync_list(struct list_head *list,
1077 struct device *dont_lock_dev)
1079 struct device *dev, *tmp;
1081 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1082 list_del_init(&dev->links.defer_sync);
1084 if (dev != dont_lock_dev)
1087 if (dev->bus->sync_state)
1088 dev->bus->sync_state(dev);
1089 else if (dev->driver && dev->driver->sync_state)
1090 dev->driver->sync_state(dev);
1092 if (dev != dont_lock_dev)
1099 void device_links_supplier_sync_state_pause(void)
1101 device_links_write_lock();
1102 defer_sync_state_count++;
1103 device_links_write_unlock();
1106 void device_links_supplier_sync_state_resume(void)
1108 struct device *dev, *tmp;
1109 LIST_HEAD(sync_list);
1111 device_links_write_lock();
1112 if (!defer_sync_state_count) {
1113 WARN(true, "Unmatched sync_state pause/resume!");
1116 defer_sync_state_count--;
1117 if (defer_sync_state_count)
1120 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1122 * Delete from deferred_sync list before queuing it to
1123 * sync_list because defer_sync is used for both lists.
1125 list_del_init(&dev->links.defer_sync);
1126 __device_links_queue_sync_state(dev, &sync_list);
1129 device_links_write_unlock();
1131 device_links_flush_sync_list(&sync_list, NULL);
1134 static int sync_state_resume_initcall(void)
1136 device_links_supplier_sync_state_resume();
1139 late_initcall(sync_state_resume_initcall);
1141 static void __device_links_supplier_defer_sync(struct device *sup)
1143 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1144 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1147 static void device_link_drop_managed(struct device_link *link)
1149 link->flags &= ~DL_FLAG_MANAGED;
1150 WRITE_ONCE(link->status, DL_STATE_NONE);
1151 kref_put(&link->kref, __device_link_del);
1154 static ssize_t waiting_for_supplier_show(struct device *dev,
1155 struct device_attribute *attr,
1161 val = !list_empty(&dev->fwnode->suppliers);
1163 return sysfs_emit(buf, "%u\n", val);
1165 static DEVICE_ATTR_RO(waiting_for_supplier);
1168 * device_links_force_bind - Prepares device to be force bound
1169 * @dev: Consumer device.
1171 * device_bind_driver() force binds a device to a driver without calling any
1172 * driver probe functions. So the consumer really isn't going to wait for any
1173 * supplier before it's bound to the driver. We still want the device link
1174 * states to be sensible when this happens.
1176 * In preparation for device_bind_driver(), this function goes through each
1177 * supplier device links and checks if the supplier is bound. If it is, then
1178 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1179 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1181 void device_links_force_bind(struct device *dev)
1183 struct device_link *link, *ln;
1185 device_links_write_lock();
1187 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1188 if (!(link->flags & DL_FLAG_MANAGED))
1191 if (link->status != DL_STATE_AVAILABLE) {
1192 device_link_drop_managed(link);
1195 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1197 dev->links.status = DL_DEV_PROBING;
1199 device_links_write_unlock();
1203 * device_links_driver_bound - Update device links after probing its driver.
1204 * @dev: Device to update the links for.
1206 * The probe has been successful, so update links from this device to any
1207 * consumers by changing their status to "available".
1209 * Also change the status of @dev's links to suppliers to "active".
1211 * Links without the DL_FLAG_MANAGED flag set are ignored.
1213 void device_links_driver_bound(struct device *dev)
1215 struct device_link *link, *ln;
1216 LIST_HEAD(sync_list);
1219 * If a device binds successfully, it's expected to have created all
1220 * the device links it needs to or make new device links as it needs
1221 * them. So, fw_devlink no longer needs to create device links to any
1222 * of the device's suppliers.
1224 * Also, if a child firmware node of this bound device is not added as
1225 * a device by now, assume it is never going to be added and make sure
1226 * other devices don't defer probe indefinitely by waiting for such a
1229 if (dev->fwnode && dev->fwnode->dev == dev) {
1230 struct fwnode_handle *child;
1231 fwnode_links_purge_suppliers(dev->fwnode);
1232 fwnode_for_each_available_child_node(dev->fwnode, child)
1233 fw_devlink_purge_absent_suppliers(child);
1235 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1237 device_links_write_lock();
1239 list_for_each_entry(link, &dev->links.consumers, s_node) {
1240 if (!(link->flags & DL_FLAG_MANAGED))
1244 * Links created during consumer probe may be in the "consumer
1245 * probe" state to start with if the supplier is still probing
1246 * when they are created and they may become "active" if the
1247 * consumer probe returns first. Skip them here.
1249 if (link->status == DL_STATE_CONSUMER_PROBE ||
1250 link->status == DL_STATE_ACTIVE)
1253 WARN_ON(link->status != DL_STATE_DORMANT);
1254 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1256 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1257 driver_deferred_probe_add(link->consumer);
1260 if (defer_sync_state_count)
1261 __device_links_supplier_defer_sync(dev);
1263 __device_links_queue_sync_state(dev, &sync_list);
1265 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1266 struct device *supplier;
1268 if (!(link->flags & DL_FLAG_MANAGED))
1271 supplier = link->supplier;
1272 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1274 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1275 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1276 * save to drop the managed link completely.
1278 device_link_drop_managed(link);
1280 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1281 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1285 * This needs to be done even for the deleted
1286 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1287 * device link that was preventing the supplier from getting a
1288 * sync_state() call.
1290 if (defer_sync_state_count)
1291 __device_links_supplier_defer_sync(supplier);
1293 __device_links_queue_sync_state(supplier, &sync_list);
1296 dev->links.status = DL_DEV_DRIVER_BOUND;
1298 device_links_write_unlock();
1300 device_links_flush_sync_list(&sync_list, dev);
1304 * __device_links_no_driver - Update links of a device without a driver.
1305 * @dev: Device without a drvier.
1307 * Delete all non-persistent links from this device to any suppliers.
1309 * Persistent links stay around, but their status is changed to "available",
1310 * unless they already are in the "supplier unbind in progress" state in which
1311 * case they need not be updated.
1313 * Links without the DL_FLAG_MANAGED flag set are ignored.
1315 static void __device_links_no_driver(struct device *dev)
1317 struct device_link *link, *ln;
1319 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1320 if (!(link->flags & DL_FLAG_MANAGED))
1323 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1324 device_link_drop_managed(link);
1328 if (link->status != DL_STATE_CONSUMER_PROBE &&
1329 link->status != DL_STATE_ACTIVE)
1332 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1333 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1335 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1336 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1340 dev->links.status = DL_DEV_NO_DRIVER;
1344 * device_links_no_driver - Update links after failing driver probe.
1345 * @dev: Device whose driver has just failed to probe.
1347 * Clean up leftover links to consumers for @dev and invoke
1348 * %__device_links_no_driver() to update links to suppliers for it as
1351 * Links without the DL_FLAG_MANAGED flag set are ignored.
1353 void device_links_no_driver(struct device *dev)
1355 struct device_link *link;
1357 device_links_write_lock();
1359 list_for_each_entry(link, &dev->links.consumers, s_node) {
1360 if (!(link->flags & DL_FLAG_MANAGED))
1364 * The probe has failed, so if the status of the link is
1365 * "consumer probe" or "active", it must have been added by
1366 * a probing consumer while this device was still probing.
1367 * Change its state to "dormant", as it represents a valid
1368 * relationship, but it is not functionally meaningful.
1370 if (link->status == DL_STATE_CONSUMER_PROBE ||
1371 link->status == DL_STATE_ACTIVE)
1372 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1375 __device_links_no_driver(dev);
1377 device_links_write_unlock();
1381 * device_links_driver_cleanup - Update links after driver removal.
1382 * @dev: Device whose driver has just gone away.
1384 * Update links to consumers for @dev by changing their status to "dormant" and
1385 * invoke %__device_links_no_driver() to update links to suppliers for it as
1388 * Links without the DL_FLAG_MANAGED flag set are ignored.
1390 void device_links_driver_cleanup(struct device *dev)
1392 struct device_link *link, *ln;
1394 device_links_write_lock();
1396 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1397 if (!(link->flags & DL_FLAG_MANAGED))
1400 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1401 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1404 * autoremove the links between this @dev and its consumer
1405 * devices that are not active, i.e. where the link state
1406 * has moved to DL_STATE_SUPPLIER_UNBIND.
1408 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1409 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1410 device_link_drop_managed(link);
1412 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1415 list_del_init(&dev->links.defer_sync);
1416 __device_links_no_driver(dev);
1418 device_links_write_unlock();
1422 * device_links_busy - Check if there are any busy links to consumers.
1423 * @dev: Device to check.
1425 * Check each consumer of the device and return 'true' if its link's status
1426 * is one of "consumer probe" or "active" (meaning that the given consumer is
1427 * probing right now or its driver is present). Otherwise, change the link
1428 * state to "supplier unbind" to prevent the consumer from being probed
1429 * successfully going forward.
1431 * Return 'false' if there are no probing or active consumers.
1433 * Links without the DL_FLAG_MANAGED flag set are ignored.
1435 bool device_links_busy(struct device *dev)
1437 struct device_link *link;
1440 device_links_write_lock();
1442 list_for_each_entry(link, &dev->links.consumers, s_node) {
1443 if (!(link->flags & DL_FLAG_MANAGED))
1446 if (link->status == DL_STATE_CONSUMER_PROBE
1447 || link->status == DL_STATE_ACTIVE) {
1451 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1454 dev->links.status = DL_DEV_UNBINDING;
1456 device_links_write_unlock();
1461 * device_links_unbind_consumers - Force unbind consumers of the given device.
1462 * @dev: Device to unbind the consumers of.
1464 * Walk the list of links to consumers for @dev and if any of them is in the
1465 * "consumer probe" state, wait for all device probes in progress to complete
1468 * If that's not the case, change the status of the link to "supplier unbind"
1469 * and check if the link was in the "active" state. If so, force the consumer
1470 * driver to unbind and start over (the consumer will not re-probe as we have
1471 * changed the state of the link already).
1473 * Links without the DL_FLAG_MANAGED flag set are ignored.
1475 void device_links_unbind_consumers(struct device *dev)
1477 struct device_link *link;
1480 device_links_write_lock();
1482 list_for_each_entry(link, &dev->links.consumers, s_node) {
1483 enum device_link_state status;
1485 if (!(link->flags & DL_FLAG_MANAGED) ||
1486 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1489 status = link->status;
1490 if (status == DL_STATE_CONSUMER_PROBE) {
1491 device_links_write_unlock();
1493 wait_for_device_probe();
1496 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1497 if (status == DL_STATE_ACTIVE) {
1498 struct device *consumer = link->consumer;
1500 get_device(consumer);
1502 device_links_write_unlock();
1504 device_release_driver_internal(consumer, NULL,
1506 put_device(consumer);
1511 device_links_write_unlock();
1515 * device_links_purge - Delete existing links to other devices.
1516 * @dev: Target device.
1518 static void device_links_purge(struct device *dev)
1520 struct device_link *link, *ln;
1522 if (dev->class == &devlink_class)
1526 * Delete all of the remaining links from this device to any other
1527 * devices (either consumers or suppliers).
1529 device_links_write_lock();
1531 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1532 WARN_ON(link->status == DL_STATE_ACTIVE);
1533 __device_link_del(&link->kref);
1536 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1537 WARN_ON(link->status != DL_STATE_DORMANT &&
1538 link->status != DL_STATE_NONE);
1539 __device_link_del(&link->kref);
1542 device_links_write_unlock();
1545 #define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1546 DL_FLAG_SYNC_STATE_ONLY)
1547 #define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1548 DL_FLAG_AUTOPROBE_CONSUMER)
1549 #define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1552 static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1553 static int __init fw_devlink_setup(char *arg)
1558 if (strcmp(arg, "off") == 0) {
1559 fw_devlink_flags = 0;
1560 } else if (strcmp(arg, "permissive") == 0) {
1561 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1562 } else if (strcmp(arg, "on") == 0) {
1563 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1564 } else if (strcmp(arg, "rpm") == 0) {
1565 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1569 early_param("fw_devlink", fw_devlink_setup);
1571 static bool fw_devlink_strict;
1572 static int __init fw_devlink_strict_setup(char *arg)
1574 return strtobool(arg, &fw_devlink_strict);
1576 early_param("fw_devlink.strict", fw_devlink_strict_setup);
1578 u32 fw_devlink_get_flags(void)
1580 return fw_devlink_flags;
1583 static bool fw_devlink_is_permissive(void)
1585 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1588 bool fw_devlink_is_strict(void)
1590 return fw_devlink_strict && !fw_devlink_is_permissive();
1593 static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1595 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1598 fwnode_call_int_op(fwnode, add_links);
1599 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1602 static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1604 struct fwnode_handle *child = NULL;
1606 fw_devlink_parse_fwnode(fwnode);
1608 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1609 fw_devlink_parse_fwtree(child);
1612 static void fw_devlink_relax_link(struct device_link *link)
1614 if (!(link->flags & DL_FLAG_INFERRED))
1617 if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE))
1620 pm_runtime_drop_link(link);
1621 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1622 dev_dbg(link->consumer, "Relaxing link with %s\n",
1623 dev_name(link->supplier));
1626 static int fw_devlink_no_driver(struct device *dev, void *data)
1628 struct device_link *link = to_devlink(dev);
1630 if (!link->supplier->can_match)
1631 fw_devlink_relax_link(link);
1636 void fw_devlink_drivers_done(void)
1638 fw_devlink_drv_reg_done = true;
1639 device_links_write_lock();
1640 class_for_each_device(&devlink_class, NULL, NULL,
1641 fw_devlink_no_driver);
1642 device_links_write_unlock();
1645 static void fw_devlink_unblock_consumers(struct device *dev)
1647 struct device_link *link;
1649 if (!fw_devlink_flags || fw_devlink_is_permissive())
1652 device_links_write_lock();
1653 list_for_each_entry(link, &dev->links.consumers, s_node)
1654 fw_devlink_relax_link(link);
1655 device_links_write_unlock();
1659 * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links
1660 * @con: Device to check dependencies for.
1661 * @sup: Device to check against.
1663 * Check if @sup depends on @con or any device dependent on it (its child or
1664 * its consumer etc). When such a cyclic dependency is found, convert all
1665 * device links created solely by fw_devlink into SYNC_STATE_ONLY device links.
1666 * This is the equivalent of doing fw_devlink=permissive just between the
1667 * devices in the cycle. We need to do this because, at this point, fw_devlink
1668 * can't tell which of these dependencies is not a real dependency.
1670 * Return 1 if a cycle is found. Otherwise, return 0.
1672 static int fw_devlink_relax_cycle(struct device *con, void *sup)
1674 struct device_link *link;
1680 ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
1684 list_for_each_entry(link, &con->links.consumers, s_node) {
1685 if ((link->flags & ~DL_FLAG_INFERRED) ==
1686 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
1689 if (!fw_devlink_relax_cycle(link->consumer, sup))
1694 fw_devlink_relax_link(link);
1700 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
1701 * @con: consumer device for the device link
1702 * @sup_handle: fwnode handle of supplier
1703 * @flags: devlink flags
1705 * This function will try to create a device link between the consumer device
1706 * @con and the supplier device represented by @sup_handle.
1708 * The supplier has to be provided as a fwnode because incorrect cycles in
1709 * fwnode links can sometimes cause the supplier device to never be created.
1710 * This function detects such cases and returns an error if it cannot create a
1711 * device link from the consumer to a missing supplier.
1714 * 0 on successfully creating a device link
1715 * -EINVAL if the device link cannot be created as expected
1716 * -EAGAIN if the device link cannot be created right now, but it may be
1717 * possible to do that in the future
1719 static int fw_devlink_create_devlink(struct device *con,
1720 struct fwnode_handle *sup_handle, u32 flags)
1722 struct device *sup_dev;
1725 sup_dev = get_dev_from_fwnode(sup_handle);
1728 * If it's one of those drivers that don't actually bind to
1729 * their device using driver core, then don't wait on this
1730 * supplier device indefinitely.
1732 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
1733 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
1739 * If this fails, it is due to cycles in device links. Just
1740 * give up on this link and treat it as invalid.
1742 if (!device_link_add(con, sup_dev, flags) &&
1743 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
1744 dev_info(con, "Fixing up cyclic dependency with %s\n",
1746 device_links_write_lock();
1747 fw_devlink_relax_cycle(con, sup_dev);
1748 device_links_write_unlock();
1749 device_link_add(con, sup_dev,
1750 FW_DEVLINK_FLAGS_PERMISSIVE);
1757 /* Supplier that's already initialized without a struct device. */
1758 if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
1762 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
1763 * cycles. So cycle detection isn't necessary and shouldn't be
1766 if (flags & DL_FLAG_SYNC_STATE_ONLY)
1770 * If we can't find the supplier device from its fwnode, it might be
1771 * due to a cyclic dependency between fwnodes. Some of these cycles can
1772 * be broken by applying logic. Check for these types of cycles and
1773 * break them so that devices in the cycle probe properly.
1775 * If the supplier's parent is dependent on the consumer, then
1776 * the consumer-supplier dependency is a false dependency. So,
1777 * treat it as an invalid link.
1779 sup_dev = fwnode_get_next_parent_dev(sup_handle);
1780 if (sup_dev && device_is_dependent(con, sup_dev)) {
1781 dev_dbg(con, "Not linking to %pfwP - False link\n",
1786 * Can't check for cycles or no cycles. So let's try
1793 put_device(sup_dev);
1798 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
1799 * @dev: Device that needs to be linked to its consumers
1801 * This function looks at all the consumer fwnodes of @dev and creates device
1802 * links between the consumer device and @dev (supplier).
1804 * If the consumer device has not been added yet, then this function creates a
1805 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
1806 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
1807 * sync_state() callback before the real consumer device gets to be added and
1810 * Once device links are created from the real consumer to @dev (supplier), the
1811 * fwnode links are deleted.
1813 static void __fw_devlink_link_to_consumers(struct device *dev)
1815 struct fwnode_handle *fwnode = dev->fwnode;
1816 struct fwnode_link *link, *tmp;
1818 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
1819 u32 dl_flags = fw_devlink_get_flags();
1820 struct device *con_dev;
1821 bool own_link = true;
1824 con_dev = get_dev_from_fwnode(link->consumer);
1826 * If consumer device is not available yet, make a "proxy"
1827 * SYNC_STATE_ONLY link from the consumer's parent device to
1828 * the supplier device. This is necessary to make sure the
1829 * supplier doesn't get a sync_state() callback before the real
1830 * consumer can create a device link to the supplier.
1832 * This proxy link step is needed to handle the case where the
1833 * consumer's parent device is added before the supplier.
1836 con_dev = fwnode_get_next_parent_dev(link->consumer);
1838 * However, if the consumer's parent device is also the
1839 * parent of the supplier, don't create a
1840 * consumer-supplier link from the parent to its child
1841 * device. Such a dependency is impossible.
1844 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
1845 put_device(con_dev);
1849 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1856 ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags);
1857 put_device(con_dev);
1858 if (!own_link || ret == -EAGAIN)
1861 list_del(&link->s_hook);
1862 list_del(&link->c_hook);
1868 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
1869 * @dev: The consumer device that needs to be linked to its suppliers
1870 * @fwnode: Root of the fwnode tree that is used to create device links
1872 * This function looks at all the supplier fwnodes of fwnode tree rooted at
1873 * @fwnode and creates device links between @dev (consumer) and all the
1874 * supplier devices of the entire fwnode tree at @fwnode.
1876 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
1877 * and the real suppliers of @dev. Once these device links are created, the
1878 * fwnode links are deleted. When such device links are successfully created,
1879 * this function is called recursively on those supplier devices. This is
1880 * needed to detect and break some invalid cycles in fwnode links. See
1881 * fw_devlink_create_devlink() for more details.
1883 * In addition, it also looks at all the suppliers of the entire fwnode tree
1884 * because some of the child devices of @dev that have not been added yet
1885 * (because @dev hasn't probed) might already have their suppliers added to
1886 * driver core. So, this function creates SYNC_STATE_ONLY device links between
1887 * @dev (consumer) and these suppliers to make sure they don't execute their
1888 * sync_state() callbacks before these child devices have a chance to create
1889 * their device links. The fwnode links that correspond to the child devices
1890 * aren't delete because they are needed later to create the device links
1891 * between the real consumer and supplier devices.
1893 static void __fw_devlink_link_to_suppliers(struct device *dev,
1894 struct fwnode_handle *fwnode)
1896 bool own_link = (dev->fwnode == fwnode);
1897 struct fwnode_link *link, *tmp;
1898 struct fwnode_handle *child = NULL;
1902 dl_flags = fw_devlink_get_flags();
1904 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1906 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
1908 struct device *sup_dev;
1909 struct fwnode_handle *sup = link->supplier;
1911 ret = fw_devlink_create_devlink(dev, sup, dl_flags);
1912 if (!own_link || ret == -EAGAIN)
1915 list_del(&link->s_hook);
1916 list_del(&link->c_hook);
1919 /* If no device link was created, nothing more to do. */
1924 * If a device link was successfully created to a supplier, we
1925 * now need to try and link the supplier to all its suppliers.
1927 * This is needed to detect and delete false dependencies in
1928 * fwnode links that haven't been converted to a device link
1929 * yet. See comments in fw_devlink_create_devlink() for more
1930 * details on the false dependency.
1932 * Without deleting these false dependencies, some devices will
1933 * never probe because they'll keep waiting for their false
1934 * dependency fwnode links to be converted to device links.
1936 sup_dev = get_dev_from_fwnode(sup);
1937 __fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode);
1938 put_device(sup_dev);
1942 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
1943 * all the descendants. This proxy link step is needed to handle the
1944 * case where the supplier is added before the consumer's parent device
1947 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1948 __fw_devlink_link_to_suppliers(dev, child);
1951 static void fw_devlink_link_device(struct device *dev)
1953 struct fwnode_handle *fwnode = dev->fwnode;
1955 if (!fw_devlink_flags)
1958 fw_devlink_parse_fwtree(fwnode);
1960 mutex_lock(&fwnode_link_lock);
1961 __fw_devlink_link_to_consumers(dev);
1962 __fw_devlink_link_to_suppliers(dev, fwnode);
1963 mutex_unlock(&fwnode_link_lock);
1966 /* Device links support end. */
1968 int (*platform_notify)(struct device *dev) = NULL;
1969 int (*platform_notify_remove)(struct device *dev) = NULL;
1970 static struct kobject *dev_kobj;
1971 struct kobject *sysfs_dev_char_kobj;
1972 struct kobject *sysfs_dev_block_kobj;
1974 static DEFINE_MUTEX(device_hotplug_lock);
1976 void lock_device_hotplug(void)
1978 mutex_lock(&device_hotplug_lock);
1981 void unlock_device_hotplug(void)
1983 mutex_unlock(&device_hotplug_lock);
1986 int lock_device_hotplug_sysfs(void)
1988 if (mutex_trylock(&device_hotplug_lock))
1991 /* Avoid busy looping (5 ms of sleep should do). */
1993 return restart_syscall();
1997 static inline int device_is_not_partition(struct device *dev)
1999 return !(dev->type == &part_type);
2002 static inline int device_is_not_partition(struct device *dev)
2008 static void device_platform_notify(struct device *dev)
2010 acpi_device_notify(dev);
2012 software_node_notify(dev);
2014 if (platform_notify)
2015 platform_notify(dev);
2018 static void device_platform_notify_remove(struct device *dev)
2020 acpi_device_notify_remove(dev);
2022 software_node_notify_remove(dev);
2024 if (platform_notify_remove)
2025 platform_notify_remove(dev);
2029 * dev_driver_string - Return a device's driver name, if at all possible
2030 * @dev: struct device to get the name of
2032 * Will return the device's driver's name if it is bound to a device. If
2033 * the device is not bound to a driver, it will return the name of the bus
2034 * it is attached to. If it is not attached to a bus either, an empty
2035 * string will be returned.
2037 const char *dev_driver_string(const struct device *dev)
2039 struct device_driver *drv;
2041 /* dev->driver can change to NULL underneath us because of unbinding,
2042 * so be careful about accessing it. dev->bus and dev->class should
2043 * never change once they are set, so they don't need special care.
2045 drv = READ_ONCE(dev->driver);
2046 return drv ? drv->name : dev_bus_name(dev);
2048 EXPORT_SYMBOL(dev_driver_string);
2050 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2052 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2055 struct device_attribute *dev_attr = to_dev_attr(attr);
2056 struct device *dev = kobj_to_dev(kobj);
2060 ret = dev_attr->show(dev, dev_attr, buf);
2061 if (ret >= (ssize_t)PAGE_SIZE) {
2062 printk("dev_attr_show: %pS returned bad count\n",
2068 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2069 const char *buf, size_t count)
2071 struct device_attribute *dev_attr = to_dev_attr(attr);
2072 struct device *dev = kobj_to_dev(kobj);
2075 if (dev_attr->store)
2076 ret = dev_attr->store(dev, dev_attr, buf, count);
2080 static const struct sysfs_ops dev_sysfs_ops = {
2081 .show = dev_attr_show,
2082 .store = dev_attr_store,
2085 #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2087 ssize_t device_store_ulong(struct device *dev,
2088 struct device_attribute *attr,
2089 const char *buf, size_t size)
2091 struct dev_ext_attribute *ea = to_ext_attr(attr);
2095 ret = kstrtoul(buf, 0, &new);
2098 *(unsigned long *)(ea->var) = new;
2099 /* Always return full write size even if we didn't consume all */
2102 EXPORT_SYMBOL_GPL(device_store_ulong);
2104 ssize_t device_show_ulong(struct device *dev,
2105 struct device_attribute *attr,
2108 struct dev_ext_attribute *ea = to_ext_attr(attr);
2109 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2111 EXPORT_SYMBOL_GPL(device_show_ulong);
2113 ssize_t device_store_int(struct device *dev,
2114 struct device_attribute *attr,
2115 const char *buf, size_t size)
2117 struct dev_ext_attribute *ea = to_ext_attr(attr);
2121 ret = kstrtol(buf, 0, &new);
2125 if (new > INT_MAX || new < INT_MIN)
2127 *(int *)(ea->var) = new;
2128 /* Always return full write size even if we didn't consume all */
2131 EXPORT_SYMBOL_GPL(device_store_int);
2133 ssize_t device_show_int(struct device *dev,
2134 struct device_attribute *attr,
2137 struct dev_ext_attribute *ea = to_ext_attr(attr);
2139 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2141 EXPORT_SYMBOL_GPL(device_show_int);
2143 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2144 const char *buf, size_t size)
2146 struct dev_ext_attribute *ea = to_ext_attr(attr);
2148 if (strtobool(buf, ea->var) < 0)
2153 EXPORT_SYMBOL_GPL(device_store_bool);
2155 ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2158 struct dev_ext_attribute *ea = to_ext_attr(attr);
2160 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2162 EXPORT_SYMBOL_GPL(device_show_bool);
2165 * device_release - free device structure.
2166 * @kobj: device's kobject.
2168 * This is called once the reference count for the object
2169 * reaches 0. We forward the call to the device's release
2170 * method, which should handle actually freeing the structure.
2172 static void device_release(struct kobject *kobj)
2174 struct device *dev = kobj_to_dev(kobj);
2175 struct device_private *p = dev->p;
2178 * Some platform devices are driven without driver attached
2179 * and managed resources may have been acquired. Make sure
2180 * all resources are released.
2182 * Drivers still can add resources into device after device
2183 * is deleted but alive, so release devres here to avoid
2184 * possible memory leak.
2186 devres_release_all(dev);
2188 kfree(dev->dma_range_map);
2192 else if (dev->type && dev->type->release)
2193 dev->type->release(dev);
2194 else if (dev->class && dev->class->dev_release)
2195 dev->class->dev_release(dev);
2197 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",
2202 static const void *device_namespace(struct kobject *kobj)
2204 struct device *dev = kobj_to_dev(kobj);
2205 const void *ns = NULL;
2207 if (dev->class && dev->class->ns_type)
2208 ns = dev->class->namespace(dev);
2213 static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2215 struct device *dev = kobj_to_dev(kobj);
2217 if (dev->class && dev->class->get_ownership)
2218 dev->class->get_ownership(dev, uid, gid);
2221 static struct kobj_type device_ktype = {
2222 .release = device_release,
2223 .sysfs_ops = &dev_sysfs_ops,
2224 .namespace = device_namespace,
2225 .get_ownership = device_get_ownership,
2229 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
2231 struct kobj_type *ktype = get_ktype(kobj);
2233 if (ktype == &device_ktype) {
2234 struct device *dev = kobj_to_dev(kobj);
2243 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
2245 struct device *dev = kobj_to_dev(kobj);
2248 return dev->bus->name;
2250 return dev->class->name;
2254 static int dev_uevent(struct kset *kset, struct kobject *kobj,
2255 struct kobj_uevent_env *env)
2257 struct device *dev = kobj_to_dev(kobj);
2260 /* add device node properties if present */
2261 if (MAJOR(dev->devt)) {
2265 kuid_t uid = GLOBAL_ROOT_UID;
2266 kgid_t gid = GLOBAL_ROOT_GID;
2268 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2269 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2270 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2272 add_uevent_var(env, "DEVNAME=%s", name);
2274 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2275 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2276 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2277 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2278 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2283 if (dev->type && dev->type->name)
2284 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2287 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2289 /* Add common DT information about the device */
2290 of_device_uevent(dev, env);
2292 /* have the bus specific function add its stuff */
2293 if (dev->bus && dev->bus->uevent) {
2294 retval = dev->bus->uevent(dev, env);
2296 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2297 dev_name(dev), __func__, retval);
2300 /* have the class specific function add its stuff */
2301 if (dev->class && dev->class->dev_uevent) {
2302 retval = dev->class->dev_uevent(dev, env);
2304 pr_debug("device: '%s': %s: class uevent() "
2305 "returned %d\n", dev_name(dev),
2309 /* have the device type specific function add its stuff */
2310 if (dev->type && dev->type->uevent) {
2311 retval = dev->type->uevent(dev, env);
2313 pr_debug("device: '%s': %s: dev_type uevent() "
2314 "returned %d\n", dev_name(dev),
2321 static const struct kset_uevent_ops device_uevent_ops = {
2322 .filter = dev_uevent_filter,
2323 .name = dev_uevent_name,
2324 .uevent = dev_uevent,
2327 static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2330 struct kobject *top_kobj;
2332 struct kobj_uevent_env *env = NULL;
2337 /* search the kset, the device belongs to */
2338 top_kobj = &dev->kobj;
2339 while (!top_kobj->kset && top_kobj->parent)
2340 top_kobj = top_kobj->parent;
2341 if (!top_kobj->kset)
2344 kset = top_kobj->kset;
2345 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2348 /* respect filter */
2349 if (kset->uevent_ops && kset->uevent_ops->filter)
2350 if (!kset->uevent_ops->filter(kset, &dev->kobj))
2353 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2357 /* let the kset specific function add its keys */
2358 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
2362 /* copy keys to file */
2363 for (i = 0; i < env->envp_idx; i++)
2364 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2370 static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2371 const char *buf, size_t count)
2375 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2378 dev_err(dev, "uevent: failed to send synthetic uevent\n");
2384 static DEVICE_ATTR_RW(uevent);
2386 static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2392 val = !dev->offline;
2394 return sysfs_emit(buf, "%u\n", val);
2397 static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2398 const char *buf, size_t count)
2403 ret = strtobool(buf, &val);
2407 ret = lock_device_hotplug_sysfs();
2411 ret = val ? device_online(dev) : device_offline(dev);
2412 unlock_device_hotplug();
2413 return ret < 0 ? ret : count;
2415 static DEVICE_ATTR_RW(online);
2417 static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2422 switch (dev->removable) {
2423 case DEVICE_REMOVABLE:
2432 return sysfs_emit(buf, "%s\n", loc);
2434 static DEVICE_ATTR_RO(removable);
2436 int device_add_groups(struct device *dev, const struct attribute_group **groups)
2438 return sysfs_create_groups(&dev->kobj, groups);
2440 EXPORT_SYMBOL_GPL(device_add_groups);
2442 void device_remove_groups(struct device *dev,
2443 const struct attribute_group **groups)
2445 sysfs_remove_groups(&dev->kobj, groups);
2447 EXPORT_SYMBOL_GPL(device_remove_groups);
2449 union device_attr_group_devres {
2450 const struct attribute_group *group;
2451 const struct attribute_group **groups;
2454 static int devm_attr_group_match(struct device *dev, void *res, void *data)
2456 return ((union device_attr_group_devres *)res)->group == data;
2459 static void devm_attr_group_remove(struct device *dev, void *res)
2461 union device_attr_group_devres *devres = res;
2462 const struct attribute_group *group = devres->group;
2464 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2465 sysfs_remove_group(&dev->kobj, group);
2468 static void devm_attr_groups_remove(struct device *dev, void *res)
2470 union device_attr_group_devres *devres = res;
2471 const struct attribute_group **groups = devres->groups;
2473 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2474 sysfs_remove_groups(&dev->kobj, groups);
2478 * devm_device_add_group - given a device, create a managed attribute group
2479 * @dev: The device to create the group for
2480 * @grp: The attribute group to create
2482 * This function creates a group for the first time. It will explicitly
2483 * warn and error if any of the attribute files being created already exist.
2485 * Returns 0 on success or error code on failure.
2487 int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2489 union device_attr_group_devres *devres;
2492 devres = devres_alloc(devm_attr_group_remove,
2493 sizeof(*devres), GFP_KERNEL);
2497 error = sysfs_create_group(&dev->kobj, grp);
2499 devres_free(devres);
2503 devres->group = grp;
2504 devres_add(dev, devres);
2507 EXPORT_SYMBOL_GPL(devm_device_add_group);
2510 * devm_device_remove_group: remove a managed group from a device
2511 * @dev: device to remove the group from
2512 * @grp: group to remove
2514 * This function removes a group of attributes from a device. The attributes
2515 * previously have to have been created for this group, otherwise it will fail.
2517 void devm_device_remove_group(struct device *dev,
2518 const struct attribute_group *grp)
2520 WARN_ON(devres_release(dev, devm_attr_group_remove,
2521 devm_attr_group_match,
2522 /* cast away const */ (void *)grp));
2524 EXPORT_SYMBOL_GPL(devm_device_remove_group);
2527 * devm_device_add_groups - create a bunch of managed attribute groups
2528 * @dev: The device to create the group for
2529 * @groups: The attribute groups to create, NULL terminated
2531 * This function creates a bunch of managed attribute groups. If an error
2532 * occurs when creating a group, all previously created groups will be
2533 * removed, unwinding everything back to the original state when this
2534 * function was called. It will explicitly warn and error if any of the
2535 * attribute files being created already exist.
2537 * Returns 0 on success or error code from sysfs_create_group on failure.
2539 int devm_device_add_groups(struct device *dev,
2540 const struct attribute_group **groups)
2542 union device_attr_group_devres *devres;
2545 devres = devres_alloc(devm_attr_groups_remove,
2546 sizeof(*devres), GFP_KERNEL);
2550 error = sysfs_create_groups(&dev->kobj, groups);
2552 devres_free(devres);
2556 devres->groups = groups;
2557 devres_add(dev, devres);
2560 EXPORT_SYMBOL_GPL(devm_device_add_groups);
2563 * devm_device_remove_groups - remove a list of managed groups
2565 * @dev: The device for the groups to be removed from
2566 * @groups: NULL terminated list of groups to be removed
2568 * If groups is not NULL, remove the specified groups from the device.
2570 void devm_device_remove_groups(struct device *dev,
2571 const struct attribute_group **groups)
2573 WARN_ON(devres_release(dev, devm_attr_groups_remove,
2574 devm_attr_group_match,
2575 /* cast away const */ (void *)groups));
2577 EXPORT_SYMBOL_GPL(devm_device_remove_groups);
2579 static int device_add_attrs(struct device *dev)
2581 struct class *class = dev->class;
2582 const struct device_type *type = dev->type;
2586 error = device_add_groups(dev, class->dev_groups);
2592 error = device_add_groups(dev, type->groups);
2594 goto err_remove_class_groups;
2597 error = device_add_groups(dev, dev->groups);
2599 goto err_remove_type_groups;
2601 if (device_supports_offline(dev) && !dev->offline_disabled) {
2602 error = device_create_file(dev, &dev_attr_online);
2604 goto err_remove_dev_groups;
2607 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2608 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2610 goto err_remove_dev_online;
2613 if (dev_removable_is_valid(dev)) {
2614 error = device_create_file(dev, &dev_attr_removable);
2616 goto err_remove_dev_waiting_for_supplier;
2621 err_remove_dev_waiting_for_supplier:
2622 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2623 err_remove_dev_online:
2624 device_remove_file(dev, &dev_attr_online);
2625 err_remove_dev_groups:
2626 device_remove_groups(dev, dev->groups);
2627 err_remove_type_groups:
2629 device_remove_groups(dev, type->groups);
2630 err_remove_class_groups:
2632 device_remove_groups(dev, class->dev_groups);
2637 static void device_remove_attrs(struct device *dev)
2639 struct class *class = dev->class;
2640 const struct device_type *type = dev->type;
2642 device_remove_file(dev, &dev_attr_removable);
2643 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2644 device_remove_file(dev, &dev_attr_online);
2645 device_remove_groups(dev, dev->groups);
2648 device_remove_groups(dev, type->groups);
2651 device_remove_groups(dev, class->dev_groups);
2654 static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2657 return print_dev_t(buf, dev->devt);
2659 static DEVICE_ATTR_RO(dev);
2662 struct kset *devices_kset;
2665 * devices_kset_move_before - Move device in the devices_kset's list.
2666 * @deva: Device to move.
2667 * @devb: Device @deva should come before.
2669 static void devices_kset_move_before(struct device *deva, struct device *devb)
2673 pr_debug("devices_kset: Moving %s before %s\n",
2674 dev_name(deva), dev_name(devb));
2675 spin_lock(&devices_kset->list_lock);
2676 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2677 spin_unlock(&devices_kset->list_lock);
2681 * devices_kset_move_after - Move device in the devices_kset's list.
2682 * @deva: Device to move
2683 * @devb: Device @deva should come after.
2685 static void devices_kset_move_after(struct device *deva, struct device *devb)
2689 pr_debug("devices_kset: Moving %s after %s\n",
2690 dev_name(deva), dev_name(devb));
2691 spin_lock(&devices_kset->list_lock);
2692 list_move(&deva->kobj.entry, &devb->kobj.entry);
2693 spin_unlock(&devices_kset->list_lock);
2697 * devices_kset_move_last - move the device to the end of devices_kset's list.
2698 * @dev: device to move
2700 void devices_kset_move_last(struct device *dev)
2704 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2705 spin_lock(&devices_kset->list_lock);
2706 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2707 spin_unlock(&devices_kset->list_lock);
2711 * device_create_file - create sysfs attribute file for device.
2713 * @attr: device attribute descriptor.
2715 int device_create_file(struct device *dev,
2716 const struct device_attribute *attr)
2721 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2722 "Attribute %s: write permission without 'store'\n",
2724 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2725 "Attribute %s: read permission without 'show'\n",
2727 error = sysfs_create_file(&dev->kobj, &attr->attr);
2732 EXPORT_SYMBOL_GPL(device_create_file);
2735 * device_remove_file - remove sysfs attribute file.
2737 * @attr: device attribute descriptor.
2739 void device_remove_file(struct device *dev,
2740 const struct device_attribute *attr)
2743 sysfs_remove_file(&dev->kobj, &attr->attr);
2745 EXPORT_SYMBOL_GPL(device_remove_file);
2748 * device_remove_file_self - remove sysfs attribute file from its own method.
2750 * @attr: device attribute descriptor.
2752 * See kernfs_remove_self() for details.
2754 bool device_remove_file_self(struct device *dev,
2755 const struct device_attribute *attr)
2758 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2762 EXPORT_SYMBOL_GPL(device_remove_file_self);
2765 * device_create_bin_file - create sysfs binary attribute file for device.
2767 * @attr: device binary attribute descriptor.
2769 int device_create_bin_file(struct device *dev,
2770 const struct bin_attribute *attr)
2772 int error = -EINVAL;
2774 error = sysfs_create_bin_file(&dev->kobj, attr);
2777 EXPORT_SYMBOL_GPL(device_create_bin_file);
2780 * device_remove_bin_file - remove sysfs binary attribute file
2782 * @attr: device binary attribute descriptor.
2784 void device_remove_bin_file(struct device *dev,
2785 const struct bin_attribute *attr)
2788 sysfs_remove_bin_file(&dev->kobj, attr);
2790 EXPORT_SYMBOL_GPL(device_remove_bin_file);
2792 static void klist_children_get(struct klist_node *n)
2794 struct device_private *p = to_device_private_parent(n);
2795 struct device *dev = p->device;
2800 static void klist_children_put(struct klist_node *n)
2802 struct device_private *p = to_device_private_parent(n);
2803 struct device *dev = p->device;
2809 * device_initialize - init device structure.
2812 * This prepares the device for use by other layers by initializing
2814 * It is the first half of device_register(), if called by
2815 * that function, though it can also be called separately, so one
2816 * may use @dev's fields. In particular, get_device()/put_device()
2817 * may be used for reference counting of @dev after calling this
2820 * All fields in @dev must be initialized by the caller to 0, except
2821 * for those explicitly set to some other value. The simplest
2822 * approach is to use kzalloc() to allocate the structure containing
2825 * NOTE: Use put_device() to give up your reference instead of freeing
2826 * @dev directly once you have called this function.
2828 void device_initialize(struct device *dev)
2830 dev->kobj.kset = devices_kset;
2831 kobject_init(&dev->kobj, &device_ktype);
2832 INIT_LIST_HEAD(&dev->dma_pools);
2833 mutex_init(&dev->mutex);
2834 #ifdef CONFIG_PROVE_LOCKING
2835 mutex_init(&dev->lockdep_mutex);
2837 lockdep_set_novalidate_class(&dev->mutex);
2838 spin_lock_init(&dev->devres_lock);
2839 INIT_LIST_HEAD(&dev->devres_head);
2840 device_pm_init(dev);
2841 set_dev_node(dev, -1);
2842 #ifdef CONFIG_GENERIC_MSI_IRQ
2843 raw_spin_lock_init(&dev->msi_lock);
2844 INIT_LIST_HEAD(&dev->msi_list);
2846 INIT_LIST_HEAD(&dev->links.consumers);
2847 INIT_LIST_HEAD(&dev->links.suppliers);
2848 INIT_LIST_HEAD(&dev->links.defer_sync);
2849 dev->links.status = DL_DEV_NO_DRIVER;
2850 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
2851 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
2852 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
2853 dev->dma_coherent = dma_default_coherent;
2855 #ifdef CONFIG_SWIOTLB
2856 dev->dma_io_tlb_mem = &io_tlb_default_mem;
2859 EXPORT_SYMBOL_GPL(device_initialize);
2861 struct kobject *virtual_device_parent(struct device *dev)
2863 static struct kobject *virtual_dir = NULL;
2866 virtual_dir = kobject_create_and_add("virtual",
2867 &devices_kset->kobj);
2873 struct kobject kobj;
2874 struct class *class;
2877 #define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2879 static void class_dir_release(struct kobject *kobj)
2881 struct class_dir *dir = to_class_dir(kobj);
2886 struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
2888 struct class_dir *dir = to_class_dir(kobj);
2889 return dir->class->ns_type;
2892 static struct kobj_type class_dir_ktype = {
2893 .release = class_dir_release,
2894 .sysfs_ops = &kobj_sysfs_ops,
2895 .child_ns_type = class_dir_child_ns_type
2898 static struct kobject *
2899 class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
2901 struct class_dir *dir;
2904 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
2906 return ERR_PTR(-ENOMEM);
2909 kobject_init(&dir->kobj, &class_dir_ktype);
2911 dir->kobj.kset = &class->p->glue_dirs;
2913 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
2915 kobject_put(&dir->kobj);
2916 return ERR_PTR(retval);
2921 static DEFINE_MUTEX(gdp_mutex);
2923 static struct kobject *get_device_parent(struct device *dev,
2924 struct device *parent)
2927 struct kobject *kobj = NULL;
2928 struct kobject *parent_kobj;
2932 /* block disks show up in /sys/block */
2933 if (sysfs_deprecated && dev->class == &block_class) {
2934 if (parent && parent->class == &block_class)
2935 return &parent->kobj;
2936 return &block_class.p->subsys.kobj;
2941 * If we have no parent, we live in "virtual".
2942 * Class-devices with a non class-device as parent, live
2943 * in a "glue" directory to prevent namespace collisions.
2946 parent_kobj = virtual_device_parent(dev);
2947 else if (parent->class && !dev->class->ns_type)
2948 return &parent->kobj;
2950 parent_kobj = &parent->kobj;
2952 mutex_lock(&gdp_mutex);
2954 /* find our class-directory at the parent and reference it */
2955 spin_lock(&dev->class->p->glue_dirs.list_lock);
2956 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
2957 if (k->parent == parent_kobj) {
2958 kobj = kobject_get(k);
2961 spin_unlock(&dev->class->p->glue_dirs.list_lock);
2963 mutex_unlock(&gdp_mutex);
2967 /* or create a new class-directory at the parent device */
2968 k = class_dir_create_and_add(dev->class, parent_kobj);
2969 /* do not emit an uevent for this simple "glue" directory */
2970 mutex_unlock(&gdp_mutex);
2974 /* subsystems can specify a default root directory for their devices */
2975 if (!parent && dev->bus && dev->bus->dev_root)
2976 return &dev->bus->dev_root->kobj;
2979 return &parent->kobj;
2983 static inline bool live_in_glue_dir(struct kobject *kobj,
2986 if (!kobj || !dev->class ||
2987 kobj->kset != &dev->class->p->glue_dirs)
2992 static inline struct kobject *get_glue_dir(struct device *dev)
2994 return dev->kobj.parent;
2998 * make sure cleaning up dir as the last step, we need to make
2999 * sure .release handler of kobject is run with holding the
3002 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3006 /* see if we live in a "glue" directory */
3007 if (!live_in_glue_dir(glue_dir, dev))
3010 mutex_lock(&gdp_mutex);
3012 * There is a race condition between removing glue directory
3013 * and adding a new device under the glue directory.
3018 * get_device_parent()
3019 * class_dir_create_and_add()
3020 * kobject_add_internal()
3021 * create_dir() // create glue_dir
3024 * get_device_parent()
3025 * kobject_get() // get glue_dir
3028 * cleanup_glue_dir()
3029 * kobject_del(glue_dir)
3032 * kobject_add_internal()
3033 * create_dir() // in glue_dir
3034 * sysfs_create_dir_ns()
3035 * kernfs_create_dir_ns(sd)
3037 * sysfs_remove_dir() // glue_dir->sd=NULL
3038 * sysfs_put() // free glue_dir->sd
3041 * kernfs_new_node(sd)
3042 * kernfs_get(glue_dir)
3046 * Before CPU1 remove last child device under glue dir, if CPU2 add
3047 * a new device under glue dir, the glue_dir kobject reference count
3048 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3049 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3050 * and sysfs_put(). This result in glue_dir->sd is freed.
3052 * Then the CPU2 will see a stale "empty" but still potentially used
3053 * glue dir around in kernfs_new_node().
3055 * In order to avoid this happening, we also should make sure that
3056 * kernfs_node for glue_dir is released in CPU1 only when refcount
3057 * for glue_dir kobj is 1.
3059 ref = kref_read(&glue_dir->kref);
3060 if (!kobject_has_children(glue_dir) && !--ref)
3061 kobject_del(glue_dir);
3062 kobject_put(glue_dir);
3063 mutex_unlock(&gdp_mutex);
3066 static int device_add_class_symlinks(struct device *dev)
3068 struct device_node *of_node = dev_of_node(dev);
3072 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3074 dev_warn(dev, "Error %d creating of_node link\n",error);
3075 /* An error here doesn't warrant bringing down the device */
3081 error = sysfs_create_link(&dev->kobj,
3082 &dev->class->p->subsys.kobj,
3087 if (dev->parent && device_is_not_partition(dev)) {
3088 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3095 /* /sys/block has directories and does not need symlinks */
3096 if (sysfs_deprecated && dev->class == &block_class)
3100 /* link in the class directory pointing to the device */
3101 error = sysfs_create_link(&dev->class->p->subsys.kobj,
3102 &dev->kobj, dev_name(dev));
3109 sysfs_remove_link(&dev->kobj, "device");
3112 sysfs_remove_link(&dev->kobj, "subsystem");
3114 sysfs_remove_link(&dev->kobj, "of_node");
3118 static void device_remove_class_symlinks(struct device *dev)
3120 if (dev_of_node(dev))
3121 sysfs_remove_link(&dev->kobj, "of_node");
3126 if (dev->parent && device_is_not_partition(dev))
3127 sysfs_remove_link(&dev->kobj, "device");
3128 sysfs_remove_link(&dev->kobj, "subsystem");
3130 if (sysfs_deprecated && dev->class == &block_class)
3133 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
3137 * dev_set_name - set a device name
3139 * @fmt: format string for the device's name
3141 int dev_set_name(struct device *dev, const char *fmt, ...)
3146 va_start(vargs, fmt);
3147 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3151 EXPORT_SYMBOL_GPL(dev_set_name);
3154 * device_to_dev_kobj - select a /sys/dev/ directory for the device
3157 * By default we select char/ for new entries. Setting class->dev_obj
3158 * to NULL prevents an entry from being created. class->dev_kobj must
3159 * be set (or cleared) before any devices are registered to the class
3160 * otherwise device_create_sys_dev_entry() and
3161 * device_remove_sys_dev_entry() will disagree about the presence of
3164 static struct kobject *device_to_dev_kobj(struct device *dev)
3166 struct kobject *kobj;
3169 kobj = dev->class->dev_kobj;
3171 kobj = sysfs_dev_char_kobj;
3176 static int device_create_sys_dev_entry(struct device *dev)
3178 struct kobject *kobj = device_to_dev_kobj(dev);
3183 format_dev_t(devt_str, dev->devt);
3184 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3190 static void device_remove_sys_dev_entry(struct device *dev)
3192 struct kobject *kobj = device_to_dev_kobj(dev);
3196 format_dev_t(devt_str, dev->devt);
3197 sysfs_remove_link(kobj, devt_str);
3201 static int device_private_init(struct device *dev)
3203 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3206 dev->p->device = dev;
3207 klist_init(&dev->p->klist_children, klist_children_get,
3208 klist_children_put);
3209 INIT_LIST_HEAD(&dev->p->deferred_probe);
3214 * device_add - add device to device hierarchy.
3217 * This is part 2 of device_register(), though may be called
3218 * separately _iff_ device_initialize() has been called separately.
3220 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3221 * to the global and sibling lists for the device, then
3222 * adds it to the other relevant subsystems of the driver model.
3224 * Do not call this routine or device_register() more than once for
3225 * any device structure. The driver model core is not designed to work
3226 * with devices that get unregistered and then spring back to life.
3227 * (Among other things, it's very hard to guarantee that all references
3228 * to the previous incarnation of @dev have been dropped.) Allocate
3229 * and register a fresh new struct device instead.
3231 * NOTE: _Never_ directly free @dev after calling this function, even
3232 * if it returned an error! Always use put_device() to give up your
3233 * reference instead.
3235 * Rule of thumb is: if device_add() succeeds, you should call
3236 * device_del() when you want to get rid of it. If device_add() has
3237 * *not* succeeded, use *only* put_device() to drop the reference
3240 int device_add(struct device *dev)
3242 struct device *parent;
3243 struct kobject *kobj;
3244 struct class_interface *class_intf;
3245 int error = -EINVAL;
3246 struct kobject *glue_dir = NULL;
3248 dev = get_device(dev);
3253 error = device_private_init(dev);
3259 * for statically allocated devices, which should all be converted
3260 * some day, we need to initialize the name. We prevent reading back
3261 * the name, and force the use of dev_name()
3263 if (dev->init_name) {
3264 dev_set_name(dev, "%s", dev->init_name);
3265 dev->init_name = NULL;
3268 /* subsystems can specify simple device enumeration */
3269 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
3270 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3272 if (!dev_name(dev)) {
3277 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3279 parent = get_device(dev->parent);
3280 kobj = get_device_parent(dev, parent);
3282 error = PTR_ERR(kobj);
3286 dev->kobj.parent = kobj;
3288 /* use parent numa_node */
3289 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3290 set_dev_node(dev, dev_to_node(parent));
3292 /* first, register with generic layer. */
3293 /* we require the name to be set before, and pass NULL */
3294 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3296 glue_dir = get_glue_dir(dev);
3300 /* notify platform of device entry */
3301 device_platform_notify(dev);
3303 error = device_create_file(dev, &dev_attr_uevent);
3307 error = device_add_class_symlinks(dev);
3310 error = device_add_attrs(dev);
3313 error = bus_add_device(dev);
3316 error = dpm_sysfs_add(dev);
3321 if (MAJOR(dev->devt)) {
3322 error = device_create_file(dev, &dev_attr_dev);
3326 error = device_create_sys_dev_entry(dev);
3330 devtmpfs_create_node(dev);
3333 /* Notify clients of device addition. This call must come
3334 * after dpm_sysfs_add() and before kobject_uevent().
3337 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3338 BUS_NOTIFY_ADD_DEVICE, dev);
3340 kobject_uevent(&dev->kobj, KOBJ_ADD);
3343 * Check if any of the other devices (consumers) have been waiting for
3344 * this device (supplier) to be added so that they can create a device
3347 * This needs to happen after device_pm_add() because device_link_add()
3348 * requires the supplier be registered before it's called.
3350 * But this also needs to happen before bus_probe_device() to make sure
3351 * waiting consumers can link to it before the driver is bound to the
3352 * device and the driver sync_state callback is called for this device.
3354 if (dev->fwnode && !dev->fwnode->dev) {
3355 dev->fwnode->dev = dev;
3356 fw_devlink_link_device(dev);
3359 bus_probe_device(dev);
3362 * If all driver registration is done and a newly added device doesn't
3363 * match with any driver, don't block its consumers from probing in
3364 * case the consumer device is able to operate without this supplier.
3366 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3367 fw_devlink_unblock_consumers(dev);
3370 klist_add_tail(&dev->p->knode_parent,
3371 &parent->p->klist_children);
3374 mutex_lock(&dev->class->p->mutex);
3375 /* tie the class to the device */
3376 klist_add_tail(&dev->p->knode_class,
3377 &dev->class->p->klist_devices);
3379 /* notify any interfaces that the device is here */
3380 list_for_each_entry(class_intf,
3381 &dev->class->p->interfaces, node)
3382 if (class_intf->add_dev)
3383 class_intf->add_dev(dev, class_intf);
3384 mutex_unlock(&dev->class->p->mutex);
3390 if (MAJOR(dev->devt))
3391 device_remove_file(dev, &dev_attr_dev);
3393 device_pm_remove(dev);
3394 dpm_sysfs_remove(dev);
3396 bus_remove_device(dev);
3398 device_remove_attrs(dev);
3400 device_remove_class_symlinks(dev);
3402 device_remove_file(dev, &dev_attr_uevent);
3404 device_platform_notify_remove(dev);
3405 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3406 glue_dir = get_glue_dir(dev);
3407 kobject_del(&dev->kobj);
3409 cleanup_glue_dir(dev, glue_dir);
3417 EXPORT_SYMBOL_GPL(device_add);
3420 * device_register - register a device with the system.
3421 * @dev: pointer to the device structure
3423 * This happens in two clean steps - initialize the device
3424 * and add it to the system. The two steps can be called
3425 * separately, but this is the easiest and most common.
3426 * I.e. you should only call the two helpers separately if
3427 * have a clearly defined need to use and refcount the device
3428 * before it is added to the hierarchy.
3430 * For more information, see the kerneldoc for device_initialize()
3433 * NOTE: _Never_ directly free @dev after calling this function, even
3434 * if it returned an error! Always use put_device() to give up the
3435 * reference initialized in this function instead.
3437 int device_register(struct device *dev)
3439 device_initialize(dev);
3440 return device_add(dev);
3442 EXPORT_SYMBOL_GPL(device_register);
3445 * get_device - increment reference count for device.
3448 * This simply forwards the call to kobject_get(), though
3449 * we do take care to provide for the case that we get a NULL
3450 * pointer passed in.
3452 struct device *get_device(struct device *dev)
3454 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3456 EXPORT_SYMBOL_GPL(get_device);
3459 * put_device - decrement reference count.
3460 * @dev: device in question.
3462 void put_device(struct device *dev)
3464 /* might_sleep(); */
3466 kobject_put(&dev->kobj);
3468 EXPORT_SYMBOL_GPL(put_device);
3470 bool kill_device(struct device *dev)
3473 * Require the device lock and set the "dead" flag to guarantee that
3474 * the update behavior is consistent with the other bitfields near
3475 * it and that we cannot have an asynchronous probe routine trying
3476 * to run while we are tearing out the bus/class/sysfs from
3477 * underneath the device.
3479 device_lock_assert(dev);
3483 dev->p->dead = true;
3486 EXPORT_SYMBOL_GPL(kill_device);
3489 * device_del - delete device from system.
3492 * This is the first part of the device unregistration
3493 * sequence. This removes the device from the lists we control
3494 * from here, has it removed from the other driver model
3495 * subsystems it was added to in device_add(), and removes it
3496 * from the kobject hierarchy.
3498 * NOTE: this should be called manually _iff_ device_add() was
3499 * also called manually.
3501 void device_del(struct device *dev)
3503 struct device *parent = dev->parent;
3504 struct kobject *glue_dir = NULL;
3505 struct class_interface *class_intf;
3506 unsigned int noio_flag;
3512 if (dev->fwnode && dev->fwnode->dev == dev)
3513 dev->fwnode->dev = NULL;
3515 /* Notify clients of device removal. This call must come
3516 * before dpm_sysfs_remove().
3518 noio_flag = memalloc_noio_save();
3520 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3521 BUS_NOTIFY_DEL_DEVICE, dev);
3523 dpm_sysfs_remove(dev);
3525 klist_del(&dev->p->knode_parent);
3526 if (MAJOR(dev->devt)) {
3527 devtmpfs_delete_node(dev);
3528 device_remove_sys_dev_entry(dev);
3529 device_remove_file(dev, &dev_attr_dev);
3532 device_remove_class_symlinks(dev);
3534 mutex_lock(&dev->class->p->mutex);
3535 /* notify any interfaces that the device is now gone */
3536 list_for_each_entry(class_intf,
3537 &dev->class->p->interfaces, node)
3538 if (class_intf->remove_dev)
3539 class_intf->remove_dev(dev, class_intf);
3540 /* remove the device from the class list */
3541 klist_del(&dev->p->knode_class);
3542 mutex_unlock(&dev->class->p->mutex);
3544 device_remove_file(dev, &dev_attr_uevent);
3545 device_remove_attrs(dev);
3546 bus_remove_device(dev);
3547 device_pm_remove(dev);
3548 driver_deferred_probe_del(dev);
3549 device_platform_notify_remove(dev);
3550 device_remove_properties(dev);
3551 device_links_purge(dev);
3554 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3555 BUS_NOTIFY_REMOVED_DEVICE, dev);
3556 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3557 glue_dir = get_glue_dir(dev);
3558 kobject_del(&dev->kobj);
3559 cleanup_glue_dir(dev, glue_dir);
3560 memalloc_noio_restore(noio_flag);
3563 EXPORT_SYMBOL_GPL(device_del);
3566 * device_unregister - unregister device from system.
3567 * @dev: device going away.
3569 * We do this in two parts, like we do device_register(). First,
3570 * we remove it from all the subsystems with device_del(), then
3571 * we decrement the reference count via put_device(). If that
3572 * is the final reference count, the device will be cleaned up
3573 * via device_release() above. Otherwise, the structure will
3574 * stick around until the final reference to the device is dropped.
3576 void device_unregister(struct device *dev)
3578 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3582 EXPORT_SYMBOL_GPL(device_unregister);
3584 static struct device *prev_device(struct klist_iter *i)
3586 struct klist_node *n = klist_prev(i);
3587 struct device *dev = NULL;
3588 struct device_private *p;
3591 p = to_device_private_parent(n);
3597 static struct device *next_device(struct klist_iter *i)
3599 struct klist_node *n = klist_next(i);
3600 struct device *dev = NULL;
3601 struct device_private *p;
3604 p = to_device_private_parent(n);
3611 * device_get_devnode - path of device node file
3613 * @mode: returned file access mode
3614 * @uid: returned file owner
3615 * @gid: returned file group
3616 * @tmp: possibly allocated string
3618 * Return the relative path of a possible device node.
3619 * Non-default names may need to allocate a memory to compose
3620 * a name. This memory is returned in tmp and needs to be
3621 * freed by the caller.
3623 const char *device_get_devnode(struct device *dev,
3624 umode_t *mode, kuid_t *uid, kgid_t *gid,
3631 /* the device type may provide a specific name */
3632 if (dev->type && dev->type->devnode)
3633 *tmp = dev->type->devnode(dev, mode, uid, gid);
3637 /* the class may provide a specific name */
3638 if (dev->class && dev->class->devnode)
3639 *tmp = dev->class->devnode(dev, mode);
3643 /* return name without allocation, tmp == NULL */
3644 if (strchr(dev_name(dev), '!') == NULL)
3645 return dev_name(dev);
3647 /* replace '!' in the name with '/' */
3648 s = kstrdup(dev_name(dev), GFP_KERNEL);
3651 strreplace(s, '!', '/');
3656 * device_for_each_child - device child iterator.
3657 * @parent: parent struct device.
3658 * @fn: function to be called for each device.
3659 * @data: data for the callback.
3661 * Iterate over @parent's child devices, and call @fn for each,
3664 * We check the return of @fn each time. If it returns anything
3665 * other than 0, we break out and return that value.
3667 int device_for_each_child(struct device *parent, void *data,
3668 int (*fn)(struct device *dev, void *data))
3670 struct klist_iter i;
3671 struct device *child;
3677 klist_iter_init(&parent->p->klist_children, &i);
3678 while (!error && (child = next_device(&i)))
3679 error = fn(child, data);
3680 klist_iter_exit(&i);
3683 EXPORT_SYMBOL_GPL(device_for_each_child);
3686 * device_for_each_child_reverse - device child iterator in reversed order.
3687 * @parent: parent struct device.
3688 * @fn: function to be called for each device.
3689 * @data: data for the callback.
3691 * Iterate over @parent's child devices, and call @fn for each,
3694 * We check the return of @fn each time. If it returns anything
3695 * other than 0, we break out and return that value.
3697 int device_for_each_child_reverse(struct device *parent, void *data,
3698 int (*fn)(struct device *dev, void *data))
3700 struct klist_iter i;
3701 struct device *child;
3707 klist_iter_init(&parent->p->klist_children, &i);
3708 while ((child = prev_device(&i)) && !error)
3709 error = fn(child, data);
3710 klist_iter_exit(&i);
3713 EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3716 * device_find_child - device iterator for locating a particular device.
3717 * @parent: parent struct device
3718 * @match: Callback function to check device
3719 * @data: Data to pass to match function
3721 * This is similar to the device_for_each_child() function above, but it
3722 * returns a reference to a device that is 'found' for later use, as
3723 * determined by the @match callback.
3725 * The callback should return 0 if the device doesn't match and non-zero
3726 * if it does. If the callback returns non-zero and a reference to the
3727 * current device can be obtained, this function will return to the caller
3728 * and not iterate over any more devices.
3730 * NOTE: you will need to drop the reference with put_device() after use.
3732 struct device *device_find_child(struct device *parent, void *data,
3733 int (*match)(struct device *dev, void *data))
3735 struct klist_iter i;
3736 struct device *child;
3741 klist_iter_init(&parent->p->klist_children, &i);
3742 while ((child = next_device(&i)))
3743 if (match(child, data) && get_device(child))
3745 klist_iter_exit(&i);
3748 EXPORT_SYMBOL_GPL(device_find_child);
3751 * device_find_child_by_name - device iterator for locating a child device.
3752 * @parent: parent struct device
3753 * @name: name of the child device
3755 * This is similar to the device_find_child() function above, but it
3756 * returns a reference to a device that has the name @name.
3758 * NOTE: you will need to drop the reference with put_device() after use.
3760 struct device *device_find_child_by_name(struct device *parent,
3763 struct klist_iter i;
3764 struct device *child;
3769 klist_iter_init(&parent->p->klist_children, &i);
3770 while ((child = next_device(&i)))
3771 if (sysfs_streq(dev_name(child), name) && get_device(child))
3773 klist_iter_exit(&i);
3776 EXPORT_SYMBOL_GPL(device_find_child_by_name);
3778 int __init devices_init(void)
3780 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3783 dev_kobj = kobject_create_and_add("dev", NULL);
3786 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3787 if (!sysfs_dev_block_kobj)
3788 goto block_kobj_err;
3789 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3790 if (!sysfs_dev_char_kobj)
3796 kobject_put(sysfs_dev_block_kobj);
3798 kobject_put(dev_kobj);
3800 kset_unregister(devices_kset);
3804 static int device_check_offline(struct device *dev, void *not_used)
3808 ret = device_for_each_child(dev, NULL, device_check_offline);
3812 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3816 * device_offline - Prepare the device for hot-removal.
3817 * @dev: Device to be put offline.
3819 * Execute the device bus type's .offline() callback, if present, to prepare
3820 * the device for a subsequent hot-removal. If that succeeds, the device must
3821 * not be used until either it is removed or its bus type's .online() callback
3824 * Call under device_hotplug_lock.
3826 int device_offline(struct device *dev)
3830 if (dev->offline_disabled)
3833 ret = device_for_each_child(dev, NULL, device_check_offline);
3838 if (device_supports_offline(dev)) {
3842 ret = dev->bus->offline(dev);
3844 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3845 dev->offline = true;
3855 * device_online - Put the device back online after successful device_offline().
3856 * @dev: Device to be put back online.
3858 * If device_offline() has been successfully executed for @dev, but the device
3859 * has not been removed subsequently, execute its bus type's .online() callback
3860 * to indicate that the device can be used again.
3862 * Call under device_hotplug_lock.
3864 int device_online(struct device *dev)
3869 if (device_supports_offline(dev)) {
3871 ret = dev->bus->online(dev);
3873 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
3874 dev->offline = false;
3885 struct root_device {
3887 struct module *owner;
3890 static inline struct root_device *to_root_device(struct device *d)
3892 return container_of(d, struct root_device, dev);
3895 static void root_device_release(struct device *dev)
3897 kfree(to_root_device(dev));
3901 * __root_device_register - allocate and register a root device
3902 * @name: root device name
3903 * @owner: owner module of the root device, usually THIS_MODULE
3905 * This function allocates a root device and registers it
3906 * using device_register(). In order to free the returned
3907 * device, use root_device_unregister().
3909 * Root devices are dummy devices which allow other devices
3910 * to be grouped under /sys/devices. Use this function to
3911 * allocate a root device and then use it as the parent of
3912 * any device which should appear under /sys/devices/{name}
3914 * The /sys/devices/{name} directory will also contain a
3915 * 'module' symlink which points to the @owner directory
3918 * Returns &struct device pointer on success, or ERR_PTR() on error.
3920 * Note: You probably want to use root_device_register().
3922 struct device *__root_device_register(const char *name, struct module *owner)
3924 struct root_device *root;
3927 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
3929 return ERR_PTR(err);
3931 err = dev_set_name(&root->dev, "%s", name);
3934 return ERR_PTR(err);
3937 root->dev.release = root_device_release;
3939 err = device_register(&root->dev);
3941 put_device(&root->dev);
3942 return ERR_PTR(err);
3945 #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
3947 struct module_kobject *mk = &owner->mkobj;
3949 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
3951 device_unregister(&root->dev);
3952 return ERR_PTR(err);
3954 root->owner = owner;
3960 EXPORT_SYMBOL_GPL(__root_device_register);
3963 * root_device_unregister - unregister and free a root device
3964 * @dev: device going away
3966 * This function unregisters and cleans up a device that was created by
3967 * root_device_register().
3969 void root_device_unregister(struct device *dev)
3971 struct root_device *root = to_root_device(dev);
3974 sysfs_remove_link(&root->dev.kobj, "module");
3976 device_unregister(dev);
3978 EXPORT_SYMBOL_GPL(root_device_unregister);
3981 static void device_create_release(struct device *dev)
3983 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3987 static __printf(6, 0) struct device *
3988 device_create_groups_vargs(struct class *class, struct device *parent,
3989 dev_t devt, void *drvdata,
3990 const struct attribute_group **groups,
3991 const char *fmt, va_list args)
3993 struct device *dev = NULL;
3994 int retval = -ENODEV;
3996 if (class == NULL || IS_ERR(class))
3999 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4005 device_initialize(dev);
4008 dev->parent = parent;
4009 dev->groups = groups;
4010 dev->release = device_create_release;
4011 dev_set_drvdata(dev, drvdata);
4013 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4017 retval = device_add(dev);
4025 return ERR_PTR(retval);
4029 * device_create - 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 * @fmt: string for the device's name
4036 * This function can be used by char device classes. A struct device
4037 * will be created in sysfs, registered to the specified class.
4039 * A "dev" file will be created, showing the dev_t for the device, if
4040 * the dev_t is not 0,0.
4041 * If a pointer to a parent struct device is passed in, the newly created
4042 * struct device will be a child of that device in sysfs.
4043 * The pointer to the struct device will be returned from the call.
4044 * Any further sysfs files that might be required can be created using this
4047 * Returns &struct device pointer on success, or ERR_PTR() on error.
4049 * Note: the struct class passed to this function must have previously
4050 * been created with a call to class_create().
4052 struct device *device_create(struct class *class, struct device *parent,
4053 dev_t devt, void *drvdata, const char *fmt, ...)
4058 va_start(vargs, fmt);
4059 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4064 EXPORT_SYMBOL_GPL(device_create);
4067 * device_create_with_groups - creates a device and registers it with sysfs
4068 * @class: pointer to the struct class that this device should be registered to
4069 * @parent: pointer to the parent struct device of this new device, if any
4070 * @devt: the dev_t for the char device to be added
4071 * @drvdata: the data to be added to the device for callbacks
4072 * @groups: NULL-terminated list of attribute groups to be created
4073 * @fmt: string for the device's name
4075 * This function can be used by char device classes. A struct device
4076 * will be created in sysfs, registered to the specified class.
4077 * Additional attributes specified in the groups parameter will also
4078 * be created automatically.
4080 * A "dev" file will be created, showing the dev_t for the device, if
4081 * the dev_t is not 0,0.
4082 * If a pointer to a parent struct device is passed in, the newly created
4083 * struct device will be a child of that device in sysfs.
4084 * The pointer to the struct device will be returned from the call.
4085 * Any further sysfs files that might be required can be created using this
4088 * Returns &struct device pointer on success, or ERR_PTR() on error.
4090 * Note: the struct class passed to this function must have previously
4091 * been created with a call to class_create().
4093 struct device *device_create_with_groups(struct class *class,
4094 struct device *parent, dev_t devt,
4096 const struct attribute_group **groups,
4097 const char *fmt, ...)
4102 va_start(vargs, fmt);
4103 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4108 EXPORT_SYMBOL_GPL(device_create_with_groups);
4111 * device_destroy - removes a device that was created with device_create()
4112 * @class: pointer to the struct class that this device was registered with
4113 * @devt: the dev_t of the device that was previously registered
4115 * This call unregisters and cleans up a device that was created with a
4116 * call to device_create().
4118 void device_destroy(struct class *class, dev_t devt)
4122 dev = class_find_device_by_devt(class, devt);
4125 device_unregister(dev);
4128 EXPORT_SYMBOL_GPL(device_destroy);
4131 * device_rename - renames a device
4132 * @dev: the pointer to the struct device to be renamed
4133 * @new_name: the new name of the device
4135 * It is the responsibility of the caller to provide mutual
4136 * exclusion between two different calls of device_rename
4137 * on the same device to ensure that new_name is valid and
4138 * won't conflict with other devices.
4140 * Note: Don't call this function. Currently, the networking layer calls this
4141 * function, but that will change. The following text from Kay Sievers offers
4144 * Renaming devices is racy at many levels, symlinks and other stuff are not
4145 * replaced atomically, and you get a "move" uevent, but it's not easy to
4146 * connect the event to the old and new device. Device nodes are not renamed at
4147 * all, there isn't even support for that in the kernel now.
4149 * In the meantime, during renaming, your target name might be taken by another
4150 * driver, creating conflicts. Or the old name is taken directly after you
4151 * renamed it -- then you get events for the same DEVPATH, before you even see
4152 * the "move" event. It's just a mess, and nothing new should ever rely on
4153 * kernel device renaming. Besides that, it's not even implemented now for
4154 * other things than (driver-core wise very simple) network devices.
4156 * We are currently about to change network renaming in udev to completely
4157 * disallow renaming of devices in the same namespace as the kernel uses,
4158 * because we can't solve the problems properly, that arise with swapping names
4159 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
4160 * be allowed to some other name than eth[0-9]*, for the aforementioned
4163 * Make up a "real" name in the driver before you register anything, or add
4164 * some other attributes for userspace to find the device, or use udev to add
4165 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4166 * don't even want to get into that and try to implement the missing pieces in
4167 * the core. We really have other pieces to fix in the driver core mess. :)
4169 int device_rename(struct device *dev, const char *new_name)
4171 struct kobject *kobj = &dev->kobj;
4172 char *old_device_name = NULL;
4175 dev = get_device(dev);
4179 dev_dbg(dev, "renaming to %s\n", new_name);
4181 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4182 if (!old_device_name) {
4188 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
4189 kobj, old_device_name,
4190 new_name, kobject_namespace(kobj));
4195 error = kobject_rename(kobj, new_name);
4202 kfree(old_device_name);
4206 EXPORT_SYMBOL_GPL(device_rename);
4208 static int device_move_class_links(struct device *dev,
4209 struct device *old_parent,
4210 struct device *new_parent)
4215 sysfs_remove_link(&dev->kobj, "device");
4217 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4223 * device_move - moves a device to a new parent
4224 * @dev: the pointer to the struct device to be moved
4225 * @new_parent: the new parent of the device (can be NULL)
4226 * @dpm_order: how to reorder the dpm_list
4228 int device_move(struct device *dev, struct device *new_parent,
4229 enum dpm_order dpm_order)
4232 struct device *old_parent;
4233 struct kobject *new_parent_kobj;
4235 dev = get_device(dev);
4240 new_parent = get_device(new_parent);
4241 new_parent_kobj = get_device_parent(dev, new_parent);
4242 if (IS_ERR(new_parent_kobj)) {
4243 error = PTR_ERR(new_parent_kobj);
4244 put_device(new_parent);
4248 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4249 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4250 error = kobject_move(&dev->kobj, new_parent_kobj);
4252 cleanup_glue_dir(dev, new_parent_kobj);
4253 put_device(new_parent);
4256 old_parent = dev->parent;
4257 dev->parent = new_parent;
4259 klist_remove(&dev->p->knode_parent);
4261 klist_add_tail(&dev->p->knode_parent,
4262 &new_parent->p->klist_children);
4263 set_dev_node(dev, dev_to_node(new_parent));
4267 error = device_move_class_links(dev, old_parent, new_parent);
4269 /* We ignore errors on cleanup since we're hosed anyway... */
4270 device_move_class_links(dev, new_parent, old_parent);
4271 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4273 klist_remove(&dev->p->knode_parent);
4274 dev->parent = old_parent;
4276 klist_add_tail(&dev->p->knode_parent,
4277 &old_parent->p->klist_children);
4278 set_dev_node(dev, dev_to_node(old_parent));
4281 cleanup_glue_dir(dev, new_parent_kobj);
4282 put_device(new_parent);
4286 switch (dpm_order) {
4287 case DPM_ORDER_NONE:
4289 case DPM_ORDER_DEV_AFTER_PARENT:
4290 device_pm_move_after(dev, new_parent);
4291 devices_kset_move_after(dev, new_parent);
4293 case DPM_ORDER_PARENT_BEFORE_DEV:
4294 device_pm_move_before(new_parent, dev);
4295 devices_kset_move_before(new_parent, dev);
4297 case DPM_ORDER_DEV_LAST:
4298 device_pm_move_last(dev);
4299 devices_kset_move_last(dev);
4303 put_device(old_parent);
4309 EXPORT_SYMBOL_GPL(device_move);
4311 static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4314 struct kobject *kobj = &dev->kobj;
4315 struct class *class = dev->class;
4316 const struct device_type *type = dev->type;
4321 * Change the device groups of the device class for @dev to
4324 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4332 * Change the device groups of the device type for @dev to
4335 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4341 /* Change the device groups of @dev to @kuid/@kgid. */
4342 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4346 if (device_supports_offline(dev) && !dev->offline_disabled) {
4347 /* Change online device attributes of @dev to @kuid/@kgid. */
4348 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4358 * device_change_owner - change the owner of an existing device.
4360 * @kuid: new owner's kuid
4361 * @kgid: new owner's kgid
4363 * This changes the owner of @dev and its corresponding sysfs entries to
4364 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4367 * Returns 0 on success or error code on failure.
4369 int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4372 struct kobject *kobj = &dev->kobj;
4374 dev = get_device(dev);
4379 * Change the kobject and the default attributes and groups of the
4380 * ktype associated with it to @kuid/@kgid.
4382 error = sysfs_change_owner(kobj, kuid, kgid);
4387 * Change the uevent file for @dev to the new owner. The uevent file
4388 * was created in a separate step when @dev got added and we mirror
4391 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4397 * Change the device groups, the device groups associated with the
4398 * device class, and the groups associated with the device type of @dev
4401 error = device_attrs_change_owner(dev, kuid, kgid);
4405 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4410 if (sysfs_deprecated && dev->class == &block_class)
4415 * Change the owner of the symlink located in the class directory of
4416 * the device class associated with @dev which points to the actual
4417 * directory entry for @dev to @kuid/@kgid. This ensures that the
4418 * symlink shows the same permissions as its target.
4420 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
4421 dev_name(dev), kuid, kgid);
4429 EXPORT_SYMBOL_GPL(device_change_owner);
4432 * device_shutdown - call ->shutdown() on each device to shutdown.
4434 void device_shutdown(void)
4436 struct device *dev, *parent;
4438 wait_for_device_probe();
4439 device_block_probing();
4443 spin_lock(&devices_kset->list_lock);
4445 * Walk the devices list backward, shutting down each in turn.
4446 * Beware that device unplug events may also start pulling
4447 * devices offline, even as the system is shutting down.
4449 while (!list_empty(&devices_kset->list)) {
4450 dev = list_entry(devices_kset->list.prev, struct device,
4454 * hold reference count of device's parent to
4455 * prevent it from being freed because parent's
4456 * lock is to be held
4458 parent = get_device(dev->parent);
4461 * Make sure the device is off the kset list, in the
4462 * event that dev->*->shutdown() doesn't remove it.
4464 list_del_init(&dev->kobj.entry);
4465 spin_unlock(&devices_kset->list_lock);
4467 /* hold lock to avoid race with probe/release */
4469 device_lock(parent);
4472 /* Don't allow any more runtime suspends */
4473 pm_runtime_get_noresume(dev);
4474 pm_runtime_barrier(dev);
4476 if (dev->class && dev->class->shutdown_pre) {
4478 dev_info(dev, "shutdown_pre\n");
4479 dev->class->shutdown_pre(dev);
4481 if (dev->bus && dev->bus->shutdown) {
4483 dev_info(dev, "shutdown\n");
4484 dev->bus->shutdown(dev);
4485 } else if (dev->driver && dev->driver->shutdown) {
4487 dev_info(dev, "shutdown\n");
4488 dev->driver->shutdown(dev);
4493 device_unlock(parent);
4498 spin_lock(&devices_kset->list_lock);
4500 spin_unlock(&devices_kset->list_lock);
4504 * Device logging functions
4507 #ifdef CONFIG_PRINTK
4509 set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4513 memset(dev_info, 0, sizeof(*dev_info));
4516 subsys = dev->class->name;
4518 subsys = dev->bus->name;
4522 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4525 * Add device identifier DEVICE=:
4529 * +sound:card0 subsystem:devname
4531 if (MAJOR(dev->devt)) {
4534 if (strcmp(subsys, "block") == 0)
4539 snprintf(dev_info->device, sizeof(dev_info->device),
4540 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4541 } else if (strcmp(subsys, "net") == 0) {
4542 struct net_device *net = to_net_dev(dev);
4544 snprintf(dev_info->device, sizeof(dev_info->device),
4545 "n%u", net->ifindex);
4547 snprintf(dev_info->device, sizeof(dev_info->device),
4548 "+%s:%s", subsys, dev_name(dev));
4552 int dev_vprintk_emit(int level, const struct device *dev,
4553 const char *fmt, va_list args)
4555 struct dev_printk_info dev_info;
4557 set_dev_info(dev, &dev_info);
4559 return vprintk_emit(0, level, &dev_info, fmt, args);
4561 EXPORT_SYMBOL(dev_vprintk_emit);
4563 int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4568 va_start(args, fmt);
4570 r = dev_vprintk_emit(level, dev, fmt, args);
4576 EXPORT_SYMBOL(dev_printk_emit);
4578 static void __dev_printk(const char *level, const struct device *dev,
4579 struct va_format *vaf)
4582 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4583 dev_driver_string(dev), dev_name(dev), vaf);
4585 printk("%s(NULL device *): %pV", level, vaf);
4588 void _dev_printk(const char *level, const struct device *dev,
4589 const char *fmt, ...)
4591 struct va_format vaf;
4594 va_start(args, fmt);
4599 __dev_printk(level, dev, &vaf);
4603 EXPORT_SYMBOL(_dev_printk);
4605 #define define_dev_printk_level(func, kern_level) \
4606 void func(const struct device *dev, const char *fmt, ...) \
4608 struct va_format vaf; \
4611 va_start(args, fmt); \
4616 __dev_printk(kern_level, dev, &vaf); \
4620 EXPORT_SYMBOL(func);
4622 define_dev_printk_level(_dev_emerg, KERN_EMERG);
4623 define_dev_printk_level(_dev_alert, KERN_ALERT);
4624 define_dev_printk_level(_dev_crit, KERN_CRIT);
4625 define_dev_printk_level(_dev_err, KERN_ERR);
4626 define_dev_printk_level(_dev_warn, KERN_WARNING);
4627 define_dev_printk_level(_dev_notice, KERN_NOTICE);
4628 define_dev_printk_level(_dev_info, KERN_INFO);
4633 * dev_err_probe - probe error check and log helper
4634 * @dev: the pointer to the struct device
4635 * @err: error value to test
4636 * @fmt: printf-style format string
4637 * @...: arguments as specified in the format string
4639 * This helper implements common pattern present in probe functions for error
4640 * checking: print debug or error message depending if the error value is
4641 * -EPROBE_DEFER and propagate error upwards.
4642 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4643 * checked later by reading devices_deferred debugfs attribute.
4644 * It replaces code sequence::
4646 * if (err != -EPROBE_DEFER)
4647 * dev_err(dev, ...);
4649 * dev_dbg(dev, ...);
4654 * return dev_err_probe(dev, err, ...);
4659 int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4661 struct va_format vaf;
4664 va_start(args, fmt);
4668 if (err != -EPROBE_DEFER) {
4669 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4671 device_set_deferred_probe_reason(dev, &vaf);
4672 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4679 EXPORT_SYMBOL_GPL(dev_err_probe);
4681 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4683 return fwnode && !IS_ERR(fwnode->secondary);
4687 * set_primary_fwnode - Change the primary firmware node of a given device.
4688 * @dev: Device to handle.
4689 * @fwnode: New primary firmware node of the device.
4691 * Set the device's firmware node pointer to @fwnode, but if a secondary
4692 * firmware node of the device is present, preserve it.
4694 * Valid fwnode cases are:
4695 * - primary --> secondary --> -ENODEV
4696 * - primary --> NULL
4697 * - secondary --> -ENODEV
4700 void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4702 struct device *parent = dev->parent;
4703 struct fwnode_handle *fn = dev->fwnode;
4706 if (fwnode_is_primary(fn))
4710 WARN_ON(fwnode->secondary);
4711 fwnode->secondary = fn;
4713 dev->fwnode = fwnode;
4715 if (fwnode_is_primary(fn)) {
4716 dev->fwnode = fn->secondary;
4717 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
4718 if (!(parent && fn == parent->fwnode))
4719 fn->secondary = NULL;
4725 EXPORT_SYMBOL_GPL(set_primary_fwnode);
4728 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4729 * @dev: Device to handle.
4730 * @fwnode: New secondary firmware node of the device.
4732 * If a primary firmware node of the device is present, set its secondary
4733 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4736 void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4739 fwnode->secondary = ERR_PTR(-ENODEV);
4741 if (fwnode_is_primary(dev->fwnode))
4742 dev->fwnode->secondary = fwnode;
4744 dev->fwnode = fwnode;
4746 EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4749 * device_set_of_node_from_dev - reuse device-tree node of another device
4750 * @dev: device whose device-tree node is being set
4751 * @dev2: device whose device-tree node is being reused
4753 * Takes another reference to the new device-tree node after first dropping
4754 * any reference held to the old node.
4756 void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4758 of_node_put(dev->of_node);
4759 dev->of_node = of_node_get(dev2->of_node);
4760 dev->of_node_reused = true;
4762 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4764 void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
4766 dev->fwnode = fwnode;
4767 dev->of_node = to_of_node(fwnode);
4769 EXPORT_SYMBOL_GPL(device_set_node);
4771 int device_match_name(struct device *dev, const void *name)
4773 return sysfs_streq(dev_name(dev), name);
4775 EXPORT_SYMBOL_GPL(device_match_name);
4777 int device_match_of_node(struct device *dev, const void *np)
4779 return dev->of_node == np;
4781 EXPORT_SYMBOL_GPL(device_match_of_node);
4783 int device_match_fwnode(struct device *dev, const void *fwnode)
4785 return dev_fwnode(dev) == fwnode;
4787 EXPORT_SYMBOL_GPL(device_match_fwnode);
4789 int device_match_devt(struct device *dev, const void *pdevt)
4791 return dev->devt == *(dev_t *)pdevt;
4793 EXPORT_SYMBOL_GPL(device_match_devt);
4795 int device_match_acpi_dev(struct device *dev, const void *adev)
4797 return ACPI_COMPANION(dev) == adev;
4799 EXPORT_SYMBOL(device_match_acpi_dev);
4801 int device_match_any(struct device *dev, const void *unused)
4805 EXPORT_SYMBOL_GPL(device_match_any);