1 // SPDX-License-Identifier: GPL-2.0
3 * drivers/base/core.c - core driver model code (device registration, etc)
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (c) 2006 Novell, Inc.
11 #include <linux/acpi.h>
12 #include <linux/cpufreq.h>
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/fwnode.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/string.h>
20 #include <linux/kdev_t.h>
21 #include <linux/notifier.h>
23 #include <linux/of_device.h>
24 #include <linux/genhd.h>
25 #include <linux/mutex.h>
26 #include <linux/pm_runtime.h>
27 #include <linux/netdevice.h>
28 #include <linux/sched/signal.h>
29 #include <linux/sched/mm.h>
30 #include <linux/sysfs.h>
31 #include <linux/dma-map-ops.h> /* for dma_default_coherent */
34 #include "power/power.h"
36 #ifdef CONFIG_SYSFS_DEPRECATED
37 #ifdef CONFIG_SYSFS_DEPRECATED_V2
38 long sysfs_deprecated = 1;
40 long sysfs_deprecated = 0;
42 static int __init sysfs_deprecated_setup(char *arg)
44 return kstrtol(arg, 10, &sysfs_deprecated);
46 early_param("sysfs.deprecated", sysfs_deprecated_setup);
49 /* Device links support. */
50 static LIST_HEAD(deferred_sync);
51 static unsigned int defer_sync_state_count = 1;
52 static DEFINE_MUTEX(fwnode_link_lock);
53 static bool fw_devlink_is_permissive(void);
54 static bool fw_devlink_drv_reg_done;
57 * fwnode_link_add - Create a link between two fwnode_handles.
58 * @con: Consumer end of the link.
59 * @sup: Supplier end of the link.
61 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
62 * represents the detail that the firmware lists @sup fwnode as supplying a
65 * The driver core will use the fwnode link to create a device link between the
66 * two device objects corresponding to @con and @sup when they are created. The
67 * driver core will automatically delete the fwnode link between @con and @sup
70 * Attempts to create duplicate links between the same pair of fwnode handles
71 * are ignored and there is no reference counting.
73 int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
75 struct fwnode_link *link;
78 mutex_lock(&fwnode_link_lock);
80 list_for_each_entry(link, &sup->consumers, s_hook)
81 if (link->consumer == con)
84 link = kzalloc(sizeof(*link), GFP_KERNEL);
91 INIT_LIST_HEAD(&link->s_hook);
93 INIT_LIST_HEAD(&link->c_hook);
95 list_add(&link->s_hook, &sup->consumers);
96 list_add(&link->c_hook, &con->suppliers);
98 mutex_unlock(&fwnode_link_lock);
104 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
105 * @fwnode: fwnode whose supplier links need to be deleted
107 * Deletes all supplier links connecting directly to @fwnode.
109 static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
111 struct fwnode_link *link, *tmp;
113 mutex_lock(&fwnode_link_lock);
114 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
115 list_del(&link->s_hook);
116 list_del(&link->c_hook);
119 mutex_unlock(&fwnode_link_lock);
123 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
124 * @fwnode: fwnode whose consumer links need to be deleted
126 * Deletes all consumer links connecting directly to @fwnode.
128 static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
130 struct fwnode_link *link, *tmp;
132 mutex_lock(&fwnode_link_lock);
133 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
134 list_del(&link->s_hook);
135 list_del(&link->c_hook);
138 mutex_unlock(&fwnode_link_lock);
142 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
143 * @fwnode: fwnode whose links needs to be deleted
145 * Deletes all links connecting directly to a fwnode.
147 void fwnode_links_purge(struct fwnode_handle *fwnode)
149 fwnode_links_purge_suppliers(fwnode);
150 fwnode_links_purge_consumers(fwnode);
153 void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
155 struct fwnode_handle *child;
157 /* Don't purge consumer links of an added child */
161 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
162 fwnode_links_purge_consumers(fwnode);
164 fwnode_for_each_available_child_node(fwnode, child)
165 fw_devlink_purge_absent_suppliers(child);
167 EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
170 static DEFINE_MUTEX(device_links_lock);
171 DEFINE_STATIC_SRCU(device_links_srcu);
173 static inline void device_links_write_lock(void)
175 mutex_lock(&device_links_lock);
178 static inline void device_links_write_unlock(void)
180 mutex_unlock(&device_links_lock);
183 int device_links_read_lock(void) __acquires(&device_links_srcu)
185 return srcu_read_lock(&device_links_srcu);
188 void device_links_read_unlock(int idx) __releases(&device_links_srcu)
190 srcu_read_unlock(&device_links_srcu, idx);
193 int device_links_read_lock_held(void)
195 return srcu_read_lock_held(&device_links_srcu);
198 static void device_link_synchronize_removal(void)
200 synchronize_srcu(&device_links_srcu);
203 static void device_link_remove_from_lists(struct device_link *link)
205 list_del_rcu(&link->s_node);
206 list_del_rcu(&link->c_node);
208 #else /* !CONFIG_SRCU */
209 static DECLARE_RWSEM(device_links_lock);
211 static inline void device_links_write_lock(void)
213 down_write(&device_links_lock);
216 static inline void device_links_write_unlock(void)
218 up_write(&device_links_lock);
221 int device_links_read_lock(void)
223 down_read(&device_links_lock);
227 void device_links_read_unlock(int not_used)
229 up_read(&device_links_lock);
232 #ifdef CONFIG_DEBUG_LOCK_ALLOC
233 int device_links_read_lock_held(void)
235 return lockdep_is_held(&device_links_lock);
239 static inline void device_link_synchronize_removal(void)
243 static void device_link_remove_from_lists(struct device_link *link)
245 list_del(&link->s_node);
246 list_del(&link->c_node);
248 #endif /* !CONFIG_SRCU */
250 static bool device_is_ancestor(struct device *dev, struct device *target)
252 while (target->parent) {
253 target = target->parent;
261 * device_is_dependent - Check if one device depends on another one
262 * @dev: Device to check dependencies for.
263 * @target: Device to check against.
265 * Check if @target depends on @dev or any device dependent on it (its child or
266 * its consumer etc). Return 1 if that is the case or 0 otherwise.
268 int device_is_dependent(struct device *dev, void *target)
270 struct device_link *link;
274 * The "ancestors" check is needed to catch the case when the target
275 * device has not been completely initialized yet and it is still
276 * missing from the list of children of its parent device.
278 if (dev == target || device_is_ancestor(dev, target))
281 ret = device_for_each_child(dev, target, device_is_dependent);
285 list_for_each_entry(link, &dev->links.consumers, s_node) {
286 if ((link->flags & ~DL_FLAG_INFERRED) ==
287 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
290 if (link->consumer == target)
293 ret = device_is_dependent(link->consumer, target);
300 static void device_link_init_status(struct device_link *link,
301 struct device *consumer,
302 struct device *supplier)
304 switch (supplier->links.status) {
306 switch (consumer->links.status) {
309 * A consumer driver can create a link to a supplier
310 * that has not completed its probing yet as long as it
311 * knows that the supplier is already functional (for
312 * example, it has just acquired some resources from the
315 link->status = DL_STATE_CONSUMER_PROBE;
318 link->status = DL_STATE_DORMANT;
322 case DL_DEV_DRIVER_BOUND:
323 switch (consumer->links.status) {
325 link->status = DL_STATE_CONSUMER_PROBE;
327 case DL_DEV_DRIVER_BOUND:
328 link->status = DL_STATE_ACTIVE;
331 link->status = DL_STATE_AVAILABLE;
335 case DL_DEV_UNBINDING:
336 link->status = DL_STATE_SUPPLIER_UNBIND;
339 link->status = DL_STATE_DORMANT;
344 static int device_reorder_to_tail(struct device *dev, void *not_used)
346 struct device_link *link;
349 * Devices that have not been registered yet will be put to the ends
350 * of the lists during the registration, so skip them here.
352 if (device_is_registered(dev))
353 devices_kset_move_last(dev);
355 if (device_pm_initialized(dev))
356 device_pm_move_last(dev);
358 device_for_each_child(dev, NULL, device_reorder_to_tail);
359 list_for_each_entry(link, &dev->links.consumers, s_node) {
360 if ((link->flags & ~DL_FLAG_INFERRED) ==
361 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
363 device_reorder_to_tail(link->consumer, NULL);
370 * device_pm_move_to_tail - Move set of devices to the end of device lists
371 * @dev: Device to move
373 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
375 * It moves the @dev along with all of its children and all of its consumers
376 * to the ends of the device_kset and dpm_list, recursively.
378 void device_pm_move_to_tail(struct device *dev)
382 idx = device_links_read_lock();
384 device_reorder_to_tail(dev, NULL);
386 device_links_read_unlock(idx);
389 #define to_devlink(dev) container_of((dev), struct device_link, link_dev)
391 static ssize_t status_show(struct device *dev,
392 struct device_attribute *attr, char *buf)
396 switch (to_devlink(dev)->status) {
398 output = "not tracked";
400 case DL_STATE_DORMANT:
403 case DL_STATE_AVAILABLE:
404 output = "available";
406 case DL_STATE_CONSUMER_PROBE:
407 output = "consumer probing";
409 case DL_STATE_ACTIVE:
412 case DL_STATE_SUPPLIER_UNBIND:
413 output = "supplier unbinding";
420 return sysfs_emit(buf, "%s\n", output);
422 static DEVICE_ATTR_RO(status);
424 static ssize_t auto_remove_on_show(struct device *dev,
425 struct device_attribute *attr, char *buf)
427 struct device_link *link = to_devlink(dev);
430 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
431 output = "supplier unbind";
432 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
433 output = "consumer unbind";
437 return sysfs_emit(buf, "%s\n", output);
439 static DEVICE_ATTR_RO(auto_remove_on);
441 static ssize_t runtime_pm_show(struct device *dev,
442 struct device_attribute *attr, char *buf)
444 struct device_link *link = to_devlink(dev);
446 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
448 static DEVICE_ATTR_RO(runtime_pm);
450 static ssize_t sync_state_only_show(struct device *dev,
451 struct device_attribute *attr, char *buf)
453 struct device_link *link = to_devlink(dev);
455 return sysfs_emit(buf, "%d\n",
456 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
458 static DEVICE_ATTR_RO(sync_state_only);
460 static struct attribute *devlink_attrs[] = {
461 &dev_attr_status.attr,
462 &dev_attr_auto_remove_on.attr,
463 &dev_attr_runtime_pm.attr,
464 &dev_attr_sync_state_only.attr,
467 ATTRIBUTE_GROUPS(devlink);
469 static void device_link_release_fn(struct work_struct *work)
471 struct device_link *link = container_of(work, struct device_link, rm_work);
473 /* Ensure that all references to the link object have been dropped. */
474 device_link_synchronize_removal();
476 while (refcount_dec_not_one(&link->rpm_active))
477 pm_runtime_put(link->supplier);
479 put_device(link->consumer);
480 put_device(link->supplier);
484 static void devlink_dev_release(struct device *dev)
486 struct device_link *link = to_devlink(dev);
488 INIT_WORK(&link->rm_work, device_link_release_fn);
490 * It may take a while to complete this work because of the SRCU
491 * synchronization in device_link_release_fn() and if the consumer or
492 * supplier devices get deleted when it runs, so put it into the "long"
495 queue_work(system_long_wq, &link->rm_work);
498 static struct class devlink_class = {
500 .owner = THIS_MODULE,
501 .dev_groups = devlink_groups,
502 .dev_release = devlink_dev_release,
505 static int devlink_add_symlinks(struct device *dev,
506 struct class_interface *class_intf)
510 struct device_link *link = to_devlink(dev);
511 struct device *sup = link->supplier;
512 struct device *con = link->consumer;
515 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
516 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
518 len += strlen("supplier:") + 1;
519 buf = kzalloc(len, GFP_KERNEL);
523 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
527 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
531 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
532 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
536 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
537 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
544 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
545 sysfs_remove_link(&sup->kobj, buf);
547 sysfs_remove_link(&link->link_dev.kobj, "consumer");
549 sysfs_remove_link(&link->link_dev.kobj, "supplier");
555 static void devlink_remove_symlinks(struct device *dev,
556 struct class_interface *class_intf)
558 struct device_link *link = to_devlink(dev);
560 struct device *sup = link->supplier;
561 struct device *con = link->consumer;
564 sysfs_remove_link(&link->link_dev.kobj, "consumer");
565 sysfs_remove_link(&link->link_dev.kobj, "supplier");
567 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
568 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
570 len += strlen("supplier:") + 1;
571 buf = kzalloc(len, GFP_KERNEL);
573 WARN(1, "Unable to properly free device link symlinks!\n");
577 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
578 sysfs_remove_link(&con->kobj, buf);
579 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
580 sysfs_remove_link(&sup->kobj, buf);
584 static struct class_interface devlink_class_intf = {
585 .class = &devlink_class,
586 .add_dev = devlink_add_symlinks,
587 .remove_dev = devlink_remove_symlinks,
590 static int __init devlink_class_init(void)
594 ret = class_register(&devlink_class);
598 ret = class_interface_register(&devlink_class_intf);
600 class_unregister(&devlink_class);
604 postcore_initcall(devlink_class_init);
606 #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
607 DL_FLAG_AUTOREMOVE_SUPPLIER | \
608 DL_FLAG_AUTOPROBE_CONSUMER | \
609 DL_FLAG_SYNC_STATE_ONLY | \
612 #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
613 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
616 * device_link_add - Create a link between two devices.
617 * @consumer: Consumer end of the link.
618 * @supplier: Supplier end of the link.
619 * @flags: Link flags.
621 * The caller is responsible for the proper synchronization of the link creation
622 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
623 * runtime PM framework to take the link into account. Second, if the
624 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
625 * be forced into the active meta state and reference-counted upon the creation
626 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
629 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
630 * expected to release the link returned by it directly with the help of either
631 * device_link_del() or device_link_remove().
633 * If that flag is not set, however, the caller of this function is handing the
634 * management of the link over to the driver core entirely and its return value
635 * can only be used to check whether or not the link is present. In that case,
636 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
637 * flags can be used to indicate to the driver core when the link can be safely
638 * deleted. Namely, setting one of them in @flags indicates to the driver core
639 * that the link is not going to be used (by the given caller of this function)
640 * after unbinding the consumer or supplier driver, respectively, from its
641 * device, so the link can be deleted at that point. If none of them is set,
642 * the link will be maintained until one of the devices pointed to by it (either
643 * the consumer or the supplier) is unregistered.
645 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
646 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
647 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
648 * be used to request the driver core to automatically probe for a consumer
649 * driver after successfully binding a driver to the supplier device.
651 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
652 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
653 * the same time is invalid and will cause NULL to be returned upfront.
654 * However, if a device link between the given @consumer and @supplier pair
655 * exists already when this function is called for them, the existing link will
656 * be returned regardless of its current type and status (the link's flags may
657 * be modified then). The caller of this function is then expected to treat
658 * the link as though it has just been created, so (in particular) if
659 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
660 * explicitly when not needed any more (as stated above).
662 * A side effect of the link creation is re-ordering of dpm_list and the
663 * devices_kset list by moving the consumer device and all devices depending
664 * on it to the ends of these lists (that does not happen to devices that have
665 * not been registered when this function is called).
667 * The supplier device is required to be registered when this function is called
668 * and NULL will be returned if that is not the case. The consumer device need
669 * not be registered, however.
671 struct device_link *device_link_add(struct device *consumer,
672 struct device *supplier, u32 flags)
674 struct device_link *link;
676 if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS ||
677 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
678 (flags & DL_FLAG_SYNC_STATE_ONLY &&
679 (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) ||
680 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
681 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
682 DL_FLAG_AUTOREMOVE_SUPPLIER)))
685 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
686 if (pm_runtime_get_sync(supplier) < 0) {
687 pm_runtime_put_noidle(supplier);
692 if (!(flags & DL_FLAG_STATELESS))
693 flags |= DL_FLAG_MANAGED;
695 device_links_write_lock();
699 * If the supplier has not been fully registered yet or there is a
700 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
701 * the supplier already in the graph, return NULL. If the link is a
702 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
703 * because it only affects sync_state() callbacks.
705 if (!device_pm_initialized(supplier)
706 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
707 device_is_dependent(consumer, supplier))) {
713 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
714 * So, only create it if the consumer hasn't probed yet.
716 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
717 consumer->links.status != DL_DEV_NO_DRIVER &&
718 consumer->links.status != DL_DEV_PROBING) {
724 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
725 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
726 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
728 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
729 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
731 list_for_each_entry(link, &supplier->links.consumers, s_node) {
732 if (link->consumer != consumer)
735 if (link->flags & DL_FLAG_INFERRED &&
736 !(flags & DL_FLAG_INFERRED))
737 link->flags &= ~DL_FLAG_INFERRED;
739 if (flags & DL_FLAG_PM_RUNTIME) {
740 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
741 pm_runtime_new_link(consumer);
742 link->flags |= DL_FLAG_PM_RUNTIME;
744 if (flags & DL_FLAG_RPM_ACTIVE)
745 refcount_inc(&link->rpm_active);
748 if (flags & DL_FLAG_STATELESS) {
749 kref_get(&link->kref);
750 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
751 !(link->flags & DL_FLAG_STATELESS)) {
752 link->flags |= DL_FLAG_STATELESS;
755 link->flags |= DL_FLAG_STATELESS;
761 * If the life time of the link following from the new flags is
762 * longer than indicated by the flags of the existing link,
763 * update the existing link to stay around longer.
765 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
766 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
767 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
768 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
770 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
771 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
772 DL_FLAG_AUTOREMOVE_SUPPLIER);
774 if (!(link->flags & DL_FLAG_MANAGED)) {
775 kref_get(&link->kref);
776 link->flags |= DL_FLAG_MANAGED;
777 device_link_init_status(link, consumer, supplier);
779 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
780 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
781 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
788 link = kzalloc(sizeof(*link), GFP_KERNEL);
792 refcount_set(&link->rpm_active, 1);
794 get_device(supplier);
795 link->supplier = supplier;
796 INIT_LIST_HEAD(&link->s_node);
797 get_device(consumer);
798 link->consumer = consumer;
799 INIT_LIST_HEAD(&link->c_node);
801 kref_init(&link->kref);
803 link->link_dev.class = &devlink_class;
804 device_set_pm_not_required(&link->link_dev);
805 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
806 dev_bus_name(supplier), dev_name(supplier),
807 dev_bus_name(consumer), dev_name(consumer));
808 if (device_register(&link->link_dev)) {
809 put_device(consumer);
810 put_device(supplier);
816 if (flags & DL_FLAG_PM_RUNTIME) {
817 if (flags & DL_FLAG_RPM_ACTIVE)
818 refcount_inc(&link->rpm_active);
820 pm_runtime_new_link(consumer);
823 /* Determine the initial link state. */
824 if (flags & DL_FLAG_STATELESS)
825 link->status = DL_STATE_NONE;
827 device_link_init_status(link, consumer, supplier);
830 * Some callers expect the link creation during consumer driver probe to
831 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
833 if (link->status == DL_STATE_CONSUMER_PROBE &&
834 flags & DL_FLAG_PM_RUNTIME)
835 pm_runtime_resume(supplier);
837 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
838 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
840 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
842 "Linked as a sync state only consumer to %s\n",
849 * Move the consumer and all of the devices depending on it to the end
850 * of dpm_list and the devices_kset list.
852 * It is necessary to hold dpm_list locked throughout all that or else
853 * we may end up suspending with a wrong ordering of it.
855 device_reorder_to_tail(consumer, NULL);
857 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
861 device_links_write_unlock();
863 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
864 pm_runtime_put(supplier);
868 EXPORT_SYMBOL_GPL(device_link_add);
870 static void __device_link_del(struct kref *kref)
872 struct device_link *link = container_of(kref, struct device_link, kref);
874 dev_dbg(link->consumer, "Dropping the link to %s\n",
875 dev_name(link->supplier));
877 pm_runtime_drop_link(link);
879 device_link_remove_from_lists(link);
880 device_unregister(&link->link_dev);
883 static void device_link_put_kref(struct device_link *link)
885 if (link->flags & DL_FLAG_STATELESS)
886 kref_put(&link->kref, __device_link_del);
888 WARN(1, "Unable to drop a managed device link reference\n");
892 * device_link_del - Delete a stateless link between two devices.
893 * @link: Device link to delete.
895 * The caller must ensure proper synchronization of this function with runtime
896 * PM. If the link was added multiple times, it needs to be deleted as often.
897 * Care is required for hotplugged devices: Their links are purged on removal
898 * and calling device_link_del() is then no longer allowed.
900 void device_link_del(struct device_link *link)
902 device_links_write_lock();
903 device_link_put_kref(link);
904 device_links_write_unlock();
906 EXPORT_SYMBOL_GPL(device_link_del);
909 * device_link_remove - Delete a stateless link between two devices.
910 * @consumer: Consumer end of the link.
911 * @supplier: Supplier end of the link.
913 * The caller must ensure proper synchronization of this function with runtime
916 void device_link_remove(void *consumer, struct device *supplier)
918 struct device_link *link;
920 if (WARN_ON(consumer == supplier))
923 device_links_write_lock();
925 list_for_each_entry(link, &supplier->links.consumers, s_node) {
926 if (link->consumer == consumer) {
927 device_link_put_kref(link);
932 device_links_write_unlock();
934 EXPORT_SYMBOL_GPL(device_link_remove);
936 static void device_links_missing_supplier(struct device *dev)
938 struct device_link *link;
940 list_for_each_entry(link, &dev->links.suppliers, c_node) {
941 if (link->status != DL_STATE_CONSUMER_PROBE)
944 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
945 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
947 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
948 WRITE_ONCE(link->status, DL_STATE_DORMANT);
954 * device_links_check_suppliers - Check presence of supplier drivers.
955 * @dev: Consumer device.
957 * Check links from this device to any suppliers. Walk the list of the device's
958 * links to suppliers and see if all of them are available. If not, simply
959 * return -EPROBE_DEFER.
961 * We need to guarantee that the supplier will not go away after the check has
962 * been positive here. It only can go away in __device_release_driver() and
963 * that function checks the device's links to consumers. This means we need to
964 * mark the link as "consumer probe in progress" to make the supplier removal
965 * wait for us to complete (or bad things may happen).
967 * Links without the DL_FLAG_MANAGED flag set are ignored.
969 int device_links_check_suppliers(struct device *dev)
971 struct device_link *link;
975 * Device waiting for supplier to become available is not allowed to
978 mutex_lock(&fwnode_link_lock);
979 if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
980 !fw_devlink_is_permissive()) {
981 dev_dbg(dev, "probe deferral - wait for supplier %pfwP\n",
982 list_first_entry(&dev->fwnode->suppliers,
985 mutex_unlock(&fwnode_link_lock);
986 return -EPROBE_DEFER;
988 mutex_unlock(&fwnode_link_lock);
990 device_links_write_lock();
992 list_for_each_entry(link, &dev->links.suppliers, c_node) {
993 if (!(link->flags & DL_FLAG_MANAGED))
996 if (link->status != DL_STATE_AVAILABLE &&
997 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
998 device_links_missing_supplier(dev);
999 dev_dbg(dev, "probe deferral - supplier %s not ready\n",
1000 dev_name(link->supplier));
1001 ret = -EPROBE_DEFER;
1004 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1006 dev->links.status = DL_DEV_PROBING;
1008 device_links_write_unlock();
1013 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1014 * @dev: Device to call sync_state() on
1015 * @list: List head to queue the @dev on
1017 * Queues a device for a sync_state() callback when the device links write lock
1018 * isn't held. This allows the sync_state() execution flow to use device links
1019 * APIs. The caller must ensure this function is called with
1020 * device_links_write_lock() held.
1022 * This function does a get_device() to make sure the device is not freed while
1025 * So the caller must also ensure that device_links_flush_sync_list() is called
1026 * as soon as the caller releases device_links_write_lock(). This is necessary
1027 * to make sure the sync_state() is called in a timely fashion and the
1028 * put_device() is called on this device.
1030 static void __device_links_queue_sync_state(struct device *dev,
1031 struct list_head *list)
1033 struct device_link *link;
1035 if (!dev_has_sync_state(dev))
1037 if (dev->state_synced)
1040 list_for_each_entry(link, &dev->links.consumers, s_node) {
1041 if (!(link->flags & DL_FLAG_MANAGED))
1043 if (link->status != DL_STATE_ACTIVE)
1048 * Set the flag here to avoid adding the same device to a list more
1049 * than once. This can happen if new consumers get added to the device
1050 * and probed before the list is flushed.
1052 dev->state_synced = true;
1054 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1058 list_add_tail(&dev->links.defer_sync, list);
1062 * device_links_flush_sync_list - Call sync_state() on a list of devices
1063 * @list: List of devices to call sync_state() on
1064 * @dont_lock_dev: Device for which lock is already held by the caller
1066 * Calls sync_state() on all the devices that have been queued for it. This
1067 * function is used in conjunction with __device_links_queue_sync_state(). The
1068 * @dont_lock_dev parameter is useful when this function is called from a
1069 * context where a device lock is already held.
1071 static void device_links_flush_sync_list(struct list_head *list,
1072 struct device *dont_lock_dev)
1074 struct device *dev, *tmp;
1076 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1077 list_del_init(&dev->links.defer_sync);
1079 if (dev != dont_lock_dev)
1082 if (dev->bus->sync_state)
1083 dev->bus->sync_state(dev);
1084 else if (dev->driver && dev->driver->sync_state)
1085 dev->driver->sync_state(dev);
1087 if (dev != dont_lock_dev)
1094 void device_links_supplier_sync_state_pause(void)
1096 device_links_write_lock();
1097 defer_sync_state_count++;
1098 device_links_write_unlock();
1101 void device_links_supplier_sync_state_resume(void)
1103 struct device *dev, *tmp;
1104 LIST_HEAD(sync_list);
1106 device_links_write_lock();
1107 if (!defer_sync_state_count) {
1108 WARN(true, "Unmatched sync_state pause/resume!");
1111 defer_sync_state_count--;
1112 if (defer_sync_state_count)
1115 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1117 * Delete from deferred_sync list before queuing it to
1118 * sync_list because defer_sync is used for both lists.
1120 list_del_init(&dev->links.defer_sync);
1121 __device_links_queue_sync_state(dev, &sync_list);
1124 device_links_write_unlock();
1126 device_links_flush_sync_list(&sync_list, NULL);
1129 static int sync_state_resume_initcall(void)
1131 device_links_supplier_sync_state_resume();
1134 late_initcall(sync_state_resume_initcall);
1136 static void __device_links_supplier_defer_sync(struct device *sup)
1138 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1139 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1142 static void device_link_drop_managed(struct device_link *link)
1144 link->flags &= ~DL_FLAG_MANAGED;
1145 WRITE_ONCE(link->status, DL_STATE_NONE);
1146 kref_put(&link->kref, __device_link_del);
1149 static ssize_t waiting_for_supplier_show(struct device *dev,
1150 struct device_attribute *attr,
1156 val = !list_empty(&dev->fwnode->suppliers);
1158 return sysfs_emit(buf, "%u\n", val);
1160 static DEVICE_ATTR_RO(waiting_for_supplier);
1163 * device_links_force_bind - Prepares device to be force bound
1164 * @dev: Consumer device.
1166 * device_bind_driver() force binds a device to a driver without calling any
1167 * driver probe functions. So the consumer really isn't going to wait for any
1168 * supplier before it's bound to the driver. We still want the device link
1169 * states to be sensible when this happens.
1171 * In preparation for device_bind_driver(), this function goes through each
1172 * supplier device links and checks if the supplier is bound. If it is, then
1173 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1174 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1176 void device_links_force_bind(struct device *dev)
1178 struct device_link *link, *ln;
1180 device_links_write_lock();
1182 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1183 if (!(link->flags & DL_FLAG_MANAGED))
1186 if (link->status != DL_STATE_AVAILABLE) {
1187 device_link_drop_managed(link);
1190 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1192 dev->links.status = DL_DEV_PROBING;
1194 device_links_write_unlock();
1198 * device_links_driver_bound - Update device links after probing its driver.
1199 * @dev: Device to update the links for.
1201 * The probe has been successful, so update links from this device to any
1202 * consumers by changing their status to "available".
1204 * Also change the status of @dev's links to suppliers to "active".
1206 * Links without the DL_FLAG_MANAGED flag set are ignored.
1208 void device_links_driver_bound(struct device *dev)
1210 struct device_link *link, *ln;
1211 LIST_HEAD(sync_list);
1214 * If a device binds successfully, it's expected to have created all
1215 * the device links it needs to or make new device links as it needs
1216 * them. So, fw_devlink no longer needs to create device links to any
1217 * of the device's suppliers.
1219 * Also, if a child firmware node of this bound device is not added as
1220 * a device by now, assume it is never going to be added and make sure
1221 * other devices don't defer probe indefinitely by waiting for such a
1224 if (dev->fwnode && dev->fwnode->dev == dev) {
1225 struct fwnode_handle *child;
1226 fwnode_links_purge_suppliers(dev->fwnode);
1227 fwnode_for_each_available_child_node(dev->fwnode, child)
1228 fw_devlink_purge_absent_suppliers(child);
1230 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1232 device_links_write_lock();
1234 list_for_each_entry(link, &dev->links.consumers, s_node) {
1235 if (!(link->flags & DL_FLAG_MANAGED))
1239 * Links created during consumer probe may be in the "consumer
1240 * probe" state to start with if the supplier is still probing
1241 * when they are created and they may become "active" if the
1242 * consumer probe returns first. Skip them here.
1244 if (link->status == DL_STATE_CONSUMER_PROBE ||
1245 link->status == DL_STATE_ACTIVE)
1248 WARN_ON(link->status != DL_STATE_DORMANT);
1249 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1251 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1252 driver_deferred_probe_add(link->consumer);
1255 if (defer_sync_state_count)
1256 __device_links_supplier_defer_sync(dev);
1258 __device_links_queue_sync_state(dev, &sync_list);
1260 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1261 struct device *supplier;
1263 if (!(link->flags & DL_FLAG_MANAGED))
1266 supplier = link->supplier;
1267 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1269 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1270 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1271 * save to drop the managed link completely.
1273 device_link_drop_managed(link);
1275 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1276 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1280 * This needs to be done even for the deleted
1281 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1282 * device link that was preventing the supplier from getting a
1283 * sync_state() call.
1285 if (defer_sync_state_count)
1286 __device_links_supplier_defer_sync(supplier);
1288 __device_links_queue_sync_state(supplier, &sync_list);
1291 dev->links.status = DL_DEV_DRIVER_BOUND;
1293 device_links_write_unlock();
1295 device_links_flush_sync_list(&sync_list, dev);
1299 * __device_links_no_driver - Update links of a device without a driver.
1300 * @dev: Device without a drvier.
1302 * Delete all non-persistent links from this device to any suppliers.
1304 * Persistent links stay around, but their status is changed to "available",
1305 * unless they already are in the "supplier unbind in progress" state in which
1306 * case they need not be updated.
1308 * Links without the DL_FLAG_MANAGED flag set are ignored.
1310 static void __device_links_no_driver(struct device *dev)
1312 struct device_link *link, *ln;
1314 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1315 if (!(link->flags & DL_FLAG_MANAGED))
1318 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1319 device_link_drop_managed(link);
1323 if (link->status != DL_STATE_CONSUMER_PROBE &&
1324 link->status != DL_STATE_ACTIVE)
1327 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1328 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1330 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1331 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1335 dev->links.status = DL_DEV_NO_DRIVER;
1339 * device_links_no_driver - Update links after failing driver probe.
1340 * @dev: Device whose driver has just failed to probe.
1342 * Clean up leftover links to consumers for @dev and invoke
1343 * %__device_links_no_driver() to update links to suppliers for it as
1346 * Links without the DL_FLAG_MANAGED flag set are ignored.
1348 void device_links_no_driver(struct device *dev)
1350 struct device_link *link;
1352 device_links_write_lock();
1354 list_for_each_entry(link, &dev->links.consumers, s_node) {
1355 if (!(link->flags & DL_FLAG_MANAGED))
1359 * The probe has failed, so if the status of the link is
1360 * "consumer probe" or "active", it must have been added by
1361 * a probing consumer while this device was still probing.
1362 * Change its state to "dormant", as it represents a valid
1363 * relationship, but it is not functionally meaningful.
1365 if (link->status == DL_STATE_CONSUMER_PROBE ||
1366 link->status == DL_STATE_ACTIVE)
1367 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1370 __device_links_no_driver(dev);
1372 device_links_write_unlock();
1376 * device_links_driver_cleanup - Update links after driver removal.
1377 * @dev: Device whose driver has just gone away.
1379 * Update links to consumers for @dev by changing their status to "dormant" and
1380 * invoke %__device_links_no_driver() to update links to suppliers for it as
1383 * Links without the DL_FLAG_MANAGED flag set are ignored.
1385 void device_links_driver_cleanup(struct device *dev)
1387 struct device_link *link, *ln;
1389 device_links_write_lock();
1391 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1392 if (!(link->flags & DL_FLAG_MANAGED))
1395 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1396 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1399 * autoremove the links between this @dev and its consumer
1400 * devices that are not active, i.e. where the link state
1401 * has moved to DL_STATE_SUPPLIER_UNBIND.
1403 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1404 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1405 device_link_drop_managed(link);
1407 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1410 list_del_init(&dev->links.defer_sync);
1411 __device_links_no_driver(dev);
1413 device_links_write_unlock();
1417 * device_links_busy - Check if there are any busy links to consumers.
1418 * @dev: Device to check.
1420 * Check each consumer of the device and return 'true' if its link's status
1421 * is one of "consumer probe" or "active" (meaning that the given consumer is
1422 * probing right now or its driver is present). Otherwise, change the link
1423 * state to "supplier unbind" to prevent the consumer from being probed
1424 * successfully going forward.
1426 * Return 'false' if there are no probing or active consumers.
1428 * Links without the DL_FLAG_MANAGED flag set are ignored.
1430 bool device_links_busy(struct device *dev)
1432 struct device_link *link;
1435 device_links_write_lock();
1437 list_for_each_entry(link, &dev->links.consumers, s_node) {
1438 if (!(link->flags & DL_FLAG_MANAGED))
1441 if (link->status == DL_STATE_CONSUMER_PROBE
1442 || link->status == DL_STATE_ACTIVE) {
1446 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1449 dev->links.status = DL_DEV_UNBINDING;
1451 device_links_write_unlock();
1456 * device_links_unbind_consumers - Force unbind consumers of the given device.
1457 * @dev: Device to unbind the consumers of.
1459 * Walk the list of links to consumers for @dev and if any of them is in the
1460 * "consumer probe" state, wait for all device probes in progress to complete
1463 * If that's not the case, change the status of the link to "supplier unbind"
1464 * and check if the link was in the "active" state. If so, force the consumer
1465 * driver to unbind and start over (the consumer will not re-probe as we have
1466 * changed the state of the link already).
1468 * Links without the DL_FLAG_MANAGED flag set are ignored.
1470 void device_links_unbind_consumers(struct device *dev)
1472 struct device_link *link;
1475 device_links_write_lock();
1477 list_for_each_entry(link, &dev->links.consumers, s_node) {
1478 enum device_link_state status;
1480 if (!(link->flags & DL_FLAG_MANAGED) ||
1481 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1484 status = link->status;
1485 if (status == DL_STATE_CONSUMER_PROBE) {
1486 device_links_write_unlock();
1488 wait_for_device_probe();
1491 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1492 if (status == DL_STATE_ACTIVE) {
1493 struct device *consumer = link->consumer;
1495 get_device(consumer);
1497 device_links_write_unlock();
1499 device_release_driver_internal(consumer, NULL,
1501 put_device(consumer);
1506 device_links_write_unlock();
1510 * device_links_purge - Delete existing links to other devices.
1511 * @dev: Target device.
1513 static void device_links_purge(struct device *dev)
1515 struct device_link *link, *ln;
1517 if (dev->class == &devlink_class)
1521 * Delete all of the remaining links from this device to any other
1522 * devices (either consumers or suppliers).
1524 device_links_write_lock();
1526 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1527 WARN_ON(link->status == DL_STATE_ACTIVE);
1528 __device_link_del(&link->kref);
1531 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1532 WARN_ON(link->status != DL_STATE_DORMANT &&
1533 link->status != DL_STATE_NONE);
1534 __device_link_del(&link->kref);
1537 device_links_write_unlock();
1540 #define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1541 DL_FLAG_SYNC_STATE_ONLY)
1542 #define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1543 DL_FLAG_AUTOPROBE_CONSUMER)
1544 #define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1547 static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1548 static int __init fw_devlink_setup(char *arg)
1553 if (strcmp(arg, "off") == 0) {
1554 fw_devlink_flags = 0;
1555 } else if (strcmp(arg, "permissive") == 0) {
1556 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1557 } else if (strcmp(arg, "on") == 0) {
1558 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1559 } else if (strcmp(arg, "rpm") == 0) {
1560 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1564 early_param("fw_devlink", fw_devlink_setup);
1566 static bool fw_devlink_strict;
1567 static int __init fw_devlink_strict_setup(char *arg)
1569 return strtobool(arg, &fw_devlink_strict);
1571 early_param("fw_devlink.strict", fw_devlink_strict_setup);
1573 u32 fw_devlink_get_flags(void)
1575 return fw_devlink_flags;
1578 static bool fw_devlink_is_permissive(void)
1580 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1583 bool fw_devlink_is_strict(void)
1585 return fw_devlink_strict && !fw_devlink_is_permissive();
1588 static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1590 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1593 fwnode_call_int_op(fwnode, add_links);
1594 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1597 static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1599 struct fwnode_handle *child = NULL;
1601 fw_devlink_parse_fwnode(fwnode);
1603 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1604 fw_devlink_parse_fwtree(child);
1607 static void fw_devlink_relax_link(struct device_link *link)
1609 if (!(link->flags & DL_FLAG_INFERRED))
1612 if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE))
1615 pm_runtime_drop_link(link);
1616 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1617 dev_dbg(link->consumer, "Relaxing link with %s\n",
1618 dev_name(link->supplier));
1621 static int fw_devlink_no_driver(struct device *dev, void *data)
1623 struct device_link *link = to_devlink(dev);
1625 if (!link->supplier->can_match)
1626 fw_devlink_relax_link(link);
1631 void fw_devlink_drivers_done(void)
1633 fw_devlink_drv_reg_done = true;
1634 device_links_write_lock();
1635 class_for_each_device(&devlink_class, NULL, NULL,
1636 fw_devlink_no_driver);
1637 device_links_write_unlock();
1640 static void fw_devlink_unblock_consumers(struct device *dev)
1642 struct device_link *link;
1644 if (!fw_devlink_flags || fw_devlink_is_permissive())
1647 device_links_write_lock();
1648 list_for_each_entry(link, &dev->links.consumers, s_node)
1649 fw_devlink_relax_link(link);
1650 device_links_write_unlock();
1654 * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links
1655 * @con: Device to check dependencies for.
1656 * @sup: Device to check against.
1658 * Check if @sup depends on @con or any device dependent on it (its child or
1659 * its consumer etc). When such a cyclic dependency is found, convert all
1660 * device links created solely by fw_devlink into SYNC_STATE_ONLY device links.
1661 * This is the equivalent of doing fw_devlink=permissive just between the
1662 * devices in the cycle. We need to do this because, at this point, fw_devlink
1663 * can't tell which of these dependencies is not a real dependency.
1665 * Return 1 if a cycle is found. Otherwise, return 0.
1667 static int fw_devlink_relax_cycle(struct device *con, void *sup)
1669 struct device_link *link;
1675 ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
1679 list_for_each_entry(link, &con->links.consumers, s_node) {
1680 if ((link->flags & ~DL_FLAG_INFERRED) ==
1681 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
1684 if (!fw_devlink_relax_cycle(link->consumer, sup))
1689 fw_devlink_relax_link(link);
1695 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
1696 * @con: consumer device for the device link
1697 * @sup_handle: fwnode handle of supplier
1698 * @flags: devlink flags
1700 * This function will try to create a device link between the consumer device
1701 * @con and the supplier device represented by @sup_handle.
1703 * The supplier has to be provided as a fwnode because incorrect cycles in
1704 * fwnode links can sometimes cause the supplier device to never be created.
1705 * This function detects such cases and returns an error if it cannot create a
1706 * device link from the consumer to a missing supplier.
1709 * 0 on successfully creating a device link
1710 * -EINVAL if the device link cannot be created as expected
1711 * -EAGAIN if the device link cannot be created right now, but it may be
1712 * possible to do that in the future
1714 static int fw_devlink_create_devlink(struct device *con,
1715 struct fwnode_handle *sup_handle, u32 flags)
1717 struct device *sup_dev;
1720 sup_dev = get_dev_from_fwnode(sup_handle);
1723 * If it's one of those drivers that don't actually bind to
1724 * their device using driver core, then don't wait on this
1725 * supplier device indefinitely.
1727 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
1728 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
1734 * If this fails, it is due to cycles in device links. Just
1735 * give up on this link and treat it as invalid.
1737 if (!device_link_add(con, sup_dev, flags) &&
1738 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
1739 dev_info(con, "Fixing up cyclic dependency with %s\n",
1741 device_links_write_lock();
1742 fw_devlink_relax_cycle(con, sup_dev);
1743 device_links_write_unlock();
1744 device_link_add(con, sup_dev,
1745 FW_DEVLINK_FLAGS_PERMISSIVE);
1752 /* Supplier that's already initialized without a struct device. */
1753 if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
1757 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
1758 * cycles. So cycle detection isn't necessary and shouldn't be
1761 if (flags & DL_FLAG_SYNC_STATE_ONLY)
1765 * If we can't find the supplier device from its fwnode, it might be
1766 * due to a cyclic dependency between fwnodes. Some of these cycles can
1767 * be broken by applying logic. Check for these types of cycles and
1768 * break them so that devices in the cycle probe properly.
1770 * If the supplier's parent is dependent on the consumer, then
1771 * the consumer-supplier dependency is a false dependency. So,
1772 * treat it as an invalid link.
1774 sup_dev = fwnode_get_next_parent_dev(sup_handle);
1775 if (sup_dev && device_is_dependent(con, sup_dev)) {
1776 dev_dbg(con, "Not linking to %pfwP - False link\n",
1781 * Can't check for cycles or no cycles. So let's try
1788 put_device(sup_dev);
1793 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
1794 * @dev: Device that needs to be linked to its consumers
1796 * This function looks at all the consumer fwnodes of @dev and creates device
1797 * links between the consumer device and @dev (supplier).
1799 * If the consumer device has not been added yet, then this function creates a
1800 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
1801 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
1802 * sync_state() callback before the real consumer device gets to be added and
1805 * Once device links are created from the real consumer to @dev (supplier), the
1806 * fwnode links are deleted.
1808 static void __fw_devlink_link_to_consumers(struct device *dev)
1810 struct fwnode_handle *fwnode = dev->fwnode;
1811 struct fwnode_link *link, *tmp;
1813 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
1814 u32 dl_flags = fw_devlink_get_flags();
1815 struct device *con_dev;
1816 bool own_link = true;
1819 con_dev = get_dev_from_fwnode(link->consumer);
1821 * If consumer device is not available yet, make a "proxy"
1822 * SYNC_STATE_ONLY link from the consumer's parent device to
1823 * the supplier device. This is necessary to make sure the
1824 * supplier doesn't get a sync_state() callback before the real
1825 * consumer can create a device link to the supplier.
1827 * This proxy link step is needed to handle the case where the
1828 * consumer's parent device is added before the supplier.
1831 con_dev = fwnode_get_next_parent_dev(link->consumer);
1833 * However, if the consumer's parent device is also the
1834 * parent of the supplier, don't create a
1835 * consumer-supplier link from the parent to its child
1836 * device. Such a dependency is impossible.
1839 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
1840 put_device(con_dev);
1844 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1851 ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags);
1852 put_device(con_dev);
1853 if (!own_link || ret == -EAGAIN)
1856 list_del(&link->s_hook);
1857 list_del(&link->c_hook);
1863 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
1864 * @dev: The consumer device that needs to be linked to its suppliers
1865 * @fwnode: Root of the fwnode tree that is used to create device links
1867 * This function looks at all the supplier fwnodes of fwnode tree rooted at
1868 * @fwnode and creates device links between @dev (consumer) and all the
1869 * supplier devices of the entire fwnode tree at @fwnode.
1871 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
1872 * and the real suppliers of @dev. Once these device links are created, the
1873 * fwnode links are deleted. When such device links are successfully created,
1874 * this function is called recursively on those supplier devices. This is
1875 * needed to detect and break some invalid cycles in fwnode links. See
1876 * fw_devlink_create_devlink() for more details.
1878 * In addition, it also looks at all the suppliers of the entire fwnode tree
1879 * because some of the child devices of @dev that have not been added yet
1880 * (because @dev hasn't probed) might already have their suppliers added to
1881 * driver core. So, this function creates SYNC_STATE_ONLY device links between
1882 * @dev (consumer) and these suppliers to make sure they don't execute their
1883 * sync_state() callbacks before these child devices have a chance to create
1884 * their device links. The fwnode links that correspond to the child devices
1885 * aren't delete because they are needed later to create the device links
1886 * between the real consumer and supplier devices.
1888 static void __fw_devlink_link_to_suppliers(struct device *dev,
1889 struct fwnode_handle *fwnode)
1891 bool own_link = (dev->fwnode == fwnode);
1892 struct fwnode_link *link, *tmp;
1893 struct fwnode_handle *child = NULL;
1897 dl_flags = fw_devlink_get_flags();
1899 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1901 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
1903 struct device *sup_dev;
1904 struct fwnode_handle *sup = link->supplier;
1906 ret = fw_devlink_create_devlink(dev, sup, dl_flags);
1907 if (!own_link || ret == -EAGAIN)
1910 list_del(&link->s_hook);
1911 list_del(&link->c_hook);
1914 /* If no device link was created, nothing more to do. */
1919 * If a device link was successfully created to a supplier, we
1920 * now need to try and link the supplier to all its suppliers.
1922 * This is needed to detect and delete false dependencies in
1923 * fwnode links that haven't been converted to a device link
1924 * yet. See comments in fw_devlink_create_devlink() for more
1925 * details on the false dependency.
1927 * Without deleting these false dependencies, some devices will
1928 * never probe because they'll keep waiting for their false
1929 * dependency fwnode links to be converted to device links.
1931 sup_dev = get_dev_from_fwnode(sup);
1932 __fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode);
1933 put_device(sup_dev);
1937 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
1938 * all the descendants. This proxy link step is needed to handle the
1939 * case where the supplier is added before the consumer's parent device
1942 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1943 __fw_devlink_link_to_suppliers(dev, child);
1946 static void fw_devlink_link_device(struct device *dev)
1948 struct fwnode_handle *fwnode = dev->fwnode;
1950 if (!fw_devlink_flags)
1953 fw_devlink_parse_fwtree(fwnode);
1955 mutex_lock(&fwnode_link_lock);
1956 __fw_devlink_link_to_consumers(dev);
1957 __fw_devlink_link_to_suppliers(dev, fwnode);
1958 mutex_unlock(&fwnode_link_lock);
1961 /* Device links support end. */
1963 int (*platform_notify)(struct device *dev) = NULL;
1964 int (*platform_notify_remove)(struct device *dev) = NULL;
1965 static struct kobject *dev_kobj;
1966 struct kobject *sysfs_dev_char_kobj;
1967 struct kobject *sysfs_dev_block_kobj;
1969 static DEFINE_MUTEX(device_hotplug_lock);
1971 void lock_device_hotplug(void)
1973 mutex_lock(&device_hotplug_lock);
1976 void unlock_device_hotplug(void)
1978 mutex_unlock(&device_hotplug_lock);
1981 int lock_device_hotplug_sysfs(void)
1983 if (mutex_trylock(&device_hotplug_lock))
1986 /* Avoid busy looping (5 ms of sleep should do). */
1988 return restart_syscall();
1992 static inline int device_is_not_partition(struct device *dev)
1994 return !(dev->type == &part_type);
1997 static inline int device_is_not_partition(struct device *dev)
2004 device_platform_notify(struct device *dev, enum kobject_action action)
2008 ret = acpi_platform_notify(dev, action);
2012 ret = software_node_notify(dev, action);
2016 if (platform_notify && action == KOBJ_ADD)
2017 platform_notify(dev);
2018 else if (platform_notify_remove && action == KOBJ_REMOVE)
2019 platform_notify_remove(dev);
2024 * dev_driver_string - Return a device's driver name, if at all possible
2025 * @dev: struct device to get the name of
2027 * Will return the device's driver's name if it is bound to a device. If
2028 * the device is not bound to a driver, it will return the name of the bus
2029 * it is attached to. If it is not attached to a bus either, an empty
2030 * string will be returned.
2032 const char *dev_driver_string(const struct device *dev)
2034 struct device_driver *drv;
2036 /* dev->driver can change to NULL underneath us because of unbinding,
2037 * so be careful about accessing it. dev->bus and dev->class should
2038 * never change once they are set, so they don't need special care.
2040 drv = READ_ONCE(dev->driver);
2041 return drv ? drv->name : dev_bus_name(dev);
2043 EXPORT_SYMBOL(dev_driver_string);
2045 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2047 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2050 struct device_attribute *dev_attr = to_dev_attr(attr);
2051 struct device *dev = kobj_to_dev(kobj);
2055 ret = dev_attr->show(dev, dev_attr, buf);
2056 if (ret >= (ssize_t)PAGE_SIZE) {
2057 printk("dev_attr_show: %pS returned bad count\n",
2063 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2064 const char *buf, size_t count)
2066 struct device_attribute *dev_attr = to_dev_attr(attr);
2067 struct device *dev = kobj_to_dev(kobj);
2070 if (dev_attr->store)
2071 ret = dev_attr->store(dev, dev_attr, buf, count);
2075 static const struct sysfs_ops dev_sysfs_ops = {
2076 .show = dev_attr_show,
2077 .store = dev_attr_store,
2080 #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2082 ssize_t device_store_ulong(struct device *dev,
2083 struct device_attribute *attr,
2084 const char *buf, size_t size)
2086 struct dev_ext_attribute *ea = to_ext_attr(attr);
2090 ret = kstrtoul(buf, 0, &new);
2093 *(unsigned long *)(ea->var) = new;
2094 /* Always return full write size even if we didn't consume all */
2097 EXPORT_SYMBOL_GPL(device_store_ulong);
2099 ssize_t device_show_ulong(struct device *dev,
2100 struct device_attribute *attr,
2103 struct dev_ext_attribute *ea = to_ext_attr(attr);
2104 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2106 EXPORT_SYMBOL_GPL(device_show_ulong);
2108 ssize_t device_store_int(struct device *dev,
2109 struct device_attribute *attr,
2110 const char *buf, size_t size)
2112 struct dev_ext_attribute *ea = to_ext_attr(attr);
2116 ret = kstrtol(buf, 0, &new);
2120 if (new > INT_MAX || new < INT_MIN)
2122 *(int *)(ea->var) = new;
2123 /* Always return full write size even if we didn't consume all */
2126 EXPORT_SYMBOL_GPL(device_store_int);
2128 ssize_t device_show_int(struct device *dev,
2129 struct device_attribute *attr,
2132 struct dev_ext_attribute *ea = to_ext_attr(attr);
2134 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2136 EXPORT_SYMBOL_GPL(device_show_int);
2138 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2139 const char *buf, size_t size)
2141 struct dev_ext_attribute *ea = to_ext_attr(attr);
2143 if (strtobool(buf, ea->var) < 0)
2148 EXPORT_SYMBOL_GPL(device_store_bool);
2150 ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2153 struct dev_ext_attribute *ea = to_ext_attr(attr);
2155 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2157 EXPORT_SYMBOL_GPL(device_show_bool);
2160 * device_release - free device structure.
2161 * @kobj: device's kobject.
2163 * This is called once the reference count for the object
2164 * reaches 0. We forward the call to the device's release
2165 * method, which should handle actually freeing the structure.
2167 static void device_release(struct kobject *kobj)
2169 struct device *dev = kobj_to_dev(kobj);
2170 struct device_private *p = dev->p;
2173 * Some platform devices are driven without driver attached
2174 * and managed resources may have been acquired. Make sure
2175 * all resources are released.
2177 * Drivers still can add resources into device after device
2178 * is deleted but alive, so release devres here to avoid
2179 * possible memory leak.
2181 devres_release_all(dev);
2183 kfree(dev->dma_range_map);
2187 else if (dev->type && dev->type->release)
2188 dev->type->release(dev);
2189 else if (dev->class && dev->class->dev_release)
2190 dev->class->dev_release(dev);
2192 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",
2197 static const void *device_namespace(struct kobject *kobj)
2199 struct device *dev = kobj_to_dev(kobj);
2200 const void *ns = NULL;
2202 if (dev->class && dev->class->ns_type)
2203 ns = dev->class->namespace(dev);
2208 static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2210 struct device *dev = kobj_to_dev(kobj);
2212 if (dev->class && dev->class->get_ownership)
2213 dev->class->get_ownership(dev, uid, gid);
2216 static struct kobj_type device_ktype = {
2217 .release = device_release,
2218 .sysfs_ops = &dev_sysfs_ops,
2219 .namespace = device_namespace,
2220 .get_ownership = device_get_ownership,
2224 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
2226 struct kobj_type *ktype = get_ktype(kobj);
2228 if (ktype == &device_ktype) {
2229 struct device *dev = kobj_to_dev(kobj);
2238 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
2240 struct device *dev = kobj_to_dev(kobj);
2243 return dev->bus->name;
2245 return dev->class->name;
2249 static int dev_uevent(struct kset *kset, struct kobject *kobj,
2250 struct kobj_uevent_env *env)
2252 struct device *dev = kobj_to_dev(kobj);
2255 /* add device node properties if present */
2256 if (MAJOR(dev->devt)) {
2260 kuid_t uid = GLOBAL_ROOT_UID;
2261 kgid_t gid = GLOBAL_ROOT_GID;
2263 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2264 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2265 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2267 add_uevent_var(env, "DEVNAME=%s", name);
2269 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2270 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2271 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2272 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2273 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2278 if (dev->type && dev->type->name)
2279 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2282 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2284 /* Add common DT information about the device */
2285 of_device_uevent(dev, env);
2287 /* have the bus specific function add its stuff */
2288 if (dev->bus && dev->bus->uevent) {
2289 retval = dev->bus->uevent(dev, env);
2291 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2292 dev_name(dev), __func__, retval);
2295 /* have the class specific function add its stuff */
2296 if (dev->class && dev->class->dev_uevent) {
2297 retval = dev->class->dev_uevent(dev, env);
2299 pr_debug("device: '%s': %s: class uevent() "
2300 "returned %d\n", dev_name(dev),
2304 /* have the device type specific function add its stuff */
2305 if (dev->type && dev->type->uevent) {
2306 retval = dev->type->uevent(dev, env);
2308 pr_debug("device: '%s': %s: dev_type uevent() "
2309 "returned %d\n", dev_name(dev),
2316 static const struct kset_uevent_ops device_uevent_ops = {
2317 .filter = dev_uevent_filter,
2318 .name = dev_uevent_name,
2319 .uevent = dev_uevent,
2322 static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2325 struct kobject *top_kobj;
2327 struct kobj_uevent_env *env = NULL;
2332 /* search the kset, the device belongs to */
2333 top_kobj = &dev->kobj;
2334 while (!top_kobj->kset && top_kobj->parent)
2335 top_kobj = top_kobj->parent;
2336 if (!top_kobj->kset)
2339 kset = top_kobj->kset;
2340 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2343 /* respect filter */
2344 if (kset->uevent_ops && kset->uevent_ops->filter)
2345 if (!kset->uevent_ops->filter(kset, &dev->kobj))
2348 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2352 /* let the kset specific function add its keys */
2353 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
2357 /* copy keys to file */
2358 for (i = 0; i < env->envp_idx; i++)
2359 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2365 static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2366 const char *buf, size_t count)
2370 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2373 dev_err(dev, "uevent: failed to send synthetic uevent\n");
2379 static DEVICE_ATTR_RW(uevent);
2381 static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2387 val = !dev->offline;
2389 return sysfs_emit(buf, "%u\n", val);
2392 static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2393 const char *buf, size_t count)
2398 ret = strtobool(buf, &val);
2402 ret = lock_device_hotplug_sysfs();
2406 ret = val ? device_online(dev) : device_offline(dev);
2407 unlock_device_hotplug();
2408 return ret < 0 ? ret : count;
2410 static DEVICE_ATTR_RW(online);
2412 int device_add_groups(struct device *dev, const struct attribute_group **groups)
2414 return sysfs_create_groups(&dev->kobj, groups);
2416 EXPORT_SYMBOL_GPL(device_add_groups);
2418 void device_remove_groups(struct device *dev,
2419 const struct attribute_group **groups)
2421 sysfs_remove_groups(&dev->kobj, groups);
2423 EXPORT_SYMBOL_GPL(device_remove_groups);
2425 union device_attr_group_devres {
2426 const struct attribute_group *group;
2427 const struct attribute_group **groups;
2430 static int devm_attr_group_match(struct device *dev, void *res, void *data)
2432 return ((union device_attr_group_devres *)res)->group == data;
2435 static void devm_attr_group_remove(struct device *dev, void *res)
2437 union device_attr_group_devres *devres = res;
2438 const struct attribute_group *group = devres->group;
2440 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2441 sysfs_remove_group(&dev->kobj, group);
2444 static void devm_attr_groups_remove(struct device *dev, void *res)
2446 union device_attr_group_devres *devres = res;
2447 const struct attribute_group **groups = devres->groups;
2449 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2450 sysfs_remove_groups(&dev->kobj, groups);
2454 * devm_device_add_group - given a device, create a managed attribute group
2455 * @dev: The device to create the group for
2456 * @grp: The attribute group to create
2458 * This function creates a group for the first time. It will explicitly
2459 * warn and error if any of the attribute files being created already exist.
2461 * Returns 0 on success or error code on failure.
2463 int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2465 union device_attr_group_devres *devres;
2468 devres = devres_alloc(devm_attr_group_remove,
2469 sizeof(*devres), GFP_KERNEL);
2473 error = sysfs_create_group(&dev->kobj, grp);
2475 devres_free(devres);
2479 devres->group = grp;
2480 devres_add(dev, devres);
2483 EXPORT_SYMBOL_GPL(devm_device_add_group);
2486 * devm_device_remove_group: remove a managed group from a device
2487 * @dev: device to remove the group from
2488 * @grp: group to remove
2490 * This function removes a group of attributes from a device. The attributes
2491 * previously have to have been created for this group, otherwise it will fail.
2493 void devm_device_remove_group(struct device *dev,
2494 const struct attribute_group *grp)
2496 WARN_ON(devres_release(dev, devm_attr_group_remove,
2497 devm_attr_group_match,
2498 /* cast away const */ (void *)grp));
2500 EXPORT_SYMBOL_GPL(devm_device_remove_group);
2503 * devm_device_add_groups - create a bunch of managed attribute groups
2504 * @dev: The device to create the group for
2505 * @groups: The attribute groups to create, NULL terminated
2507 * This function creates a bunch of managed attribute groups. If an error
2508 * occurs when creating a group, all previously created groups will be
2509 * removed, unwinding everything back to the original state when this
2510 * function was called. It will explicitly warn and error if any of the
2511 * attribute files being created already exist.
2513 * Returns 0 on success or error code from sysfs_create_group on failure.
2515 int devm_device_add_groups(struct device *dev,
2516 const struct attribute_group **groups)
2518 union device_attr_group_devres *devres;
2521 devres = devres_alloc(devm_attr_groups_remove,
2522 sizeof(*devres), GFP_KERNEL);
2526 error = sysfs_create_groups(&dev->kobj, groups);
2528 devres_free(devres);
2532 devres->groups = groups;
2533 devres_add(dev, devres);
2536 EXPORT_SYMBOL_GPL(devm_device_add_groups);
2539 * devm_device_remove_groups - remove a list of managed groups
2541 * @dev: The device for the groups to be removed from
2542 * @groups: NULL terminated list of groups to be removed
2544 * If groups is not NULL, remove the specified groups from the device.
2546 void devm_device_remove_groups(struct device *dev,
2547 const struct attribute_group **groups)
2549 WARN_ON(devres_release(dev, devm_attr_groups_remove,
2550 devm_attr_group_match,
2551 /* cast away const */ (void *)groups));
2553 EXPORT_SYMBOL_GPL(devm_device_remove_groups);
2555 static int device_add_attrs(struct device *dev)
2557 struct class *class = dev->class;
2558 const struct device_type *type = dev->type;
2562 error = device_add_groups(dev, class->dev_groups);
2568 error = device_add_groups(dev, type->groups);
2570 goto err_remove_class_groups;
2573 error = device_add_groups(dev, dev->groups);
2575 goto err_remove_type_groups;
2577 if (device_supports_offline(dev) && !dev->offline_disabled) {
2578 error = device_create_file(dev, &dev_attr_online);
2580 goto err_remove_dev_groups;
2583 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2584 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2586 goto err_remove_dev_online;
2591 err_remove_dev_online:
2592 device_remove_file(dev, &dev_attr_online);
2593 err_remove_dev_groups:
2594 device_remove_groups(dev, dev->groups);
2595 err_remove_type_groups:
2597 device_remove_groups(dev, type->groups);
2598 err_remove_class_groups:
2600 device_remove_groups(dev, class->dev_groups);
2605 static void device_remove_attrs(struct device *dev)
2607 struct class *class = dev->class;
2608 const struct device_type *type = dev->type;
2610 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2611 device_remove_file(dev, &dev_attr_online);
2612 device_remove_groups(dev, dev->groups);
2615 device_remove_groups(dev, type->groups);
2618 device_remove_groups(dev, class->dev_groups);
2621 static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2624 return print_dev_t(buf, dev->devt);
2626 static DEVICE_ATTR_RO(dev);
2629 struct kset *devices_kset;
2632 * devices_kset_move_before - Move device in the devices_kset's list.
2633 * @deva: Device to move.
2634 * @devb: Device @deva should come before.
2636 static void devices_kset_move_before(struct device *deva, struct device *devb)
2640 pr_debug("devices_kset: Moving %s before %s\n",
2641 dev_name(deva), dev_name(devb));
2642 spin_lock(&devices_kset->list_lock);
2643 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2644 spin_unlock(&devices_kset->list_lock);
2648 * devices_kset_move_after - Move device in the devices_kset's list.
2649 * @deva: Device to move
2650 * @devb: Device @deva should come after.
2652 static void devices_kset_move_after(struct device *deva, struct device *devb)
2656 pr_debug("devices_kset: Moving %s after %s\n",
2657 dev_name(deva), dev_name(devb));
2658 spin_lock(&devices_kset->list_lock);
2659 list_move(&deva->kobj.entry, &devb->kobj.entry);
2660 spin_unlock(&devices_kset->list_lock);
2664 * devices_kset_move_last - move the device to the end of devices_kset's list.
2665 * @dev: device to move
2667 void devices_kset_move_last(struct device *dev)
2671 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2672 spin_lock(&devices_kset->list_lock);
2673 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2674 spin_unlock(&devices_kset->list_lock);
2678 * device_create_file - create sysfs attribute file for device.
2680 * @attr: device attribute descriptor.
2682 int device_create_file(struct device *dev,
2683 const struct device_attribute *attr)
2688 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2689 "Attribute %s: write permission without 'store'\n",
2691 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2692 "Attribute %s: read permission without 'show'\n",
2694 error = sysfs_create_file(&dev->kobj, &attr->attr);
2699 EXPORT_SYMBOL_GPL(device_create_file);
2702 * device_remove_file - remove sysfs attribute file.
2704 * @attr: device attribute descriptor.
2706 void device_remove_file(struct device *dev,
2707 const struct device_attribute *attr)
2710 sysfs_remove_file(&dev->kobj, &attr->attr);
2712 EXPORT_SYMBOL_GPL(device_remove_file);
2715 * device_remove_file_self - remove sysfs attribute file from its own method.
2717 * @attr: device attribute descriptor.
2719 * See kernfs_remove_self() for details.
2721 bool device_remove_file_self(struct device *dev,
2722 const struct device_attribute *attr)
2725 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2729 EXPORT_SYMBOL_GPL(device_remove_file_self);
2732 * device_create_bin_file - create sysfs binary attribute file for device.
2734 * @attr: device binary attribute descriptor.
2736 int device_create_bin_file(struct device *dev,
2737 const struct bin_attribute *attr)
2739 int error = -EINVAL;
2741 error = sysfs_create_bin_file(&dev->kobj, attr);
2744 EXPORT_SYMBOL_GPL(device_create_bin_file);
2747 * device_remove_bin_file - remove sysfs binary attribute file
2749 * @attr: device binary attribute descriptor.
2751 void device_remove_bin_file(struct device *dev,
2752 const struct bin_attribute *attr)
2755 sysfs_remove_bin_file(&dev->kobj, attr);
2757 EXPORT_SYMBOL_GPL(device_remove_bin_file);
2759 static void klist_children_get(struct klist_node *n)
2761 struct device_private *p = to_device_private_parent(n);
2762 struct device *dev = p->device;
2767 static void klist_children_put(struct klist_node *n)
2769 struct device_private *p = to_device_private_parent(n);
2770 struct device *dev = p->device;
2776 * device_initialize - init device structure.
2779 * This prepares the device for use by other layers by initializing
2781 * It is the first half of device_register(), if called by
2782 * that function, though it can also be called separately, so one
2783 * may use @dev's fields. In particular, get_device()/put_device()
2784 * may be used for reference counting of @dev after calling this
2787 * All fields in @dev must be initialized by the caller to 0, except
2788 * for those explicitly set to some other value. The simplest
2789 * approach is to use kzalloc() to allocate the structure containing
2792 * NOTE: Use put_device() to give up your reference instead of freeing
2793 * @dev directly once you have called this function.
2795 void device_initialize(struct device *dev)
2797 dev->kobj.kset = devices_kset;
2798 kobject_init(&dev->kobj, &device_ktype);
2799 INIT_LIST_HEAD(&dev->dma_pools);
2800 mutex_init(&dev->mutex);
2801 #ifdef CONFIG_PROVE_LOCKING
2802 mutex_init(&dev->lockdep_mutex);
2804 lockdep_set_novalidate_class(&dev->mutex);
2805 spin_lock_init(&dev->devres_lock);
2806 INIT_LIST_HEAD(&dev->devres_head);
2807 device_pm_init(dev);
2808 set_dev_node(dev, -1);
2809 #ifdef CONFIG_GENERIC_MSI_IRQ
2810 INIT_LIST_HEAD(&dev->msi_list);
2812 INIT_LIST_HEAD(&dev->links.consumers);
2813 INIT_LIST_HEAD(&dev->links.suppliers);
2814 INIT_LIST_HEAD(&dev->links.defer_sync);
2815 dev->links.status = DL_DEV_NO_DRIVER;
2816 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
2817 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
2818 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
2819 dev->dma_coherent = dma_default_coherent;
2822 EXPORT_SYMBOL_GPL(device_initialize);
2824 struct kobject *virtual_device_parent(struct device *dev)
2826 static struct kobject *virtual_dir = NULL;
2829 virtual_dir = kobject_create_and_add("virtual",
2830 &devices_kset->kobj);
2836 struct kobject kobj;
2837 struct class *class;
2840 #define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2842 static void class_dir_release(struct kobject *kobj)
2844 struct class_dir *dir = to_class_dir(kobj);
2849 struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
2851 struct class_dir *dir = to_class_dir(kobj);
2852 return dir->class->ns_type;
2855 static struct kobj_type class_dir_ktype = {
2856 .release = class_dir_release,
2857 .sysfs_ops = &kobj_sysfs_ops,
2858 .child_ns_type = class_dir_child_ns_type
2861 static struct kobject *
2862 class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
2864 struct class_dir *dir;
2867 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
2869 return ERR_PTR(-ENOMEM);
2872 kobject_init(&dir->kobj, &class_dir_ktype);
2874 dir->kobj.kset = &class->p->glue_dirs;
2876 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
2878 kobject_put(&dir->kobj);
2879 return ERR_PTR(retval);
2884 static DEFINE_MUTEX(gdp_mutex);
2886 static struct kobject *get_device_parent(struct device *dev,
2887 struct device *parent)
2890 struct kobject *kobj = NULL;
2891 struct kobject *parent_kobj;
2895 /* block disks show up in /sys/block */
2896 if (sysfs_deprecated && dev->class == &block_class) {
2897 if (parent && parent->class == &block_class)
2898 return &parent->kobj;
2899 return &block_class.p->subsys.kobj;
2904 * If we have no parent, we live in "virtual".
2905 * Class-devices with a non class-device as parent, live
2906 * in a "glue" directory to prevent namespace collisions.
2909 parent_kobj = virtual_device_parent(dev);
2910 else if (parent->class && !dev->class->ns_type)
2911 return &parent->kobj;
2913 parent_kobj = &parent->kobj;
2915 mutex_lock(&gdp_mutex);
2917 /* find our class-directory at the parent and reference it */
2918 spin_lock(&dev->class->p->glue_dirs.list_lock);
2919 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
2920 if (k->parent == parent_kobj) {
2921 kobj = kobject_get(k);
2924 spin_unlock(&dev->class->p->glue_dirs.list_lock);
2926 mutex_unlock(&gdp_mutex);
2930 /* or create a new class-directory at the parent device */
2931 k = class_dir_create_and_add(dev->class, parent_kobj);
2932 /* do not emit an uevent for this simple "glue" directory */
2933 mutex_unlock(&gdp_mutex);
2937 /* subsystems can specify a default root directory for their devices */
2938 if (!parent && dev->bus && dev->bus->dev_root)
2939 return &dev->bus->dev_root->kobj;
2942 return &parent->kobj;
2946 static inline bool live_in_glue_dir(struct kobject *kobj,
2949 if (!kobj || !dev->class ||
2950 kobj->kset != &dev->class->p->glue_dirs)
2955 static inline struct kobject *get_glue_dir(struct device *dev)
2957 return dev->kobj.parent;
2961 * make sure cleaning up dir as the last step, we need to make
2962 * sure .release handler of kobject is run with holding the
2965 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
2969 /* see if we live in a "glue" directory */
2970 if (!live_in_glue_dir(glue_dir, dev))
2973 mutex_lock(&gdp_mutex);
2975 * There is a race condition between removing glue directory
2976 * and adding a new device under the glue directory.
2981 * get_device_parent()
2982 * class_dir_create_and_add()
2983 * kobject_add_internal()
2984 * create_dir() // create glue_dir
2987 * get_device_parent()
2988 * kobject_get() // get glue_dir
2991 * cleanup_glue_dir()
2992 * kobject_del(glue_dir)
2995 * kobject_add_internal()
2996 * create_dir() // in glue_dir
2997 * sysfs_create_dir_ns()
2998 * kernfs_create_dir_ns(sd)
3000 * sysfs_remove_dir() // glue_dir->sd=NULL
3001 * sysfs_put() // free glue_dir->sd
3004 * kernfs_new_node(sd)
3005 * kernfs_get(glue_dir)
3009 * Before CPU1 remove last child device under glue dir, if CPU2 add
3010 * a new device under glue dir, the glue_dir kobject reference count
3011 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3012 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3013 * and sysfs_put(). This result in glue_dir->sd is freed.
3015 * Then the CPU2 will see a stale "empty" but still potentially used
3016 * glue dir around in kernfs_new_node().
3018 * In order to avoid this happening, we also should make sure that
3019 * kernfs_node for glue_dir is released in CPU1 only when refcount
3020 * for glue_dir kobj is 1.
3022 ref = kref_read(&glue_dir->kref);
3023 if (!kobject_has_children(glue_dir) && !--ref)
3024 kobject_del(glue_dir);
3025 kobject_put(glue_dir);
3026 mutex_unlock(&gdp_mutex);
3029 static int device_add_class_symlinks(struct device *dev)
3031 struct device_node *of_node = dev_of_node(dev);
3035 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3037 dev_warn(dev, "Error %d creating of_node link\n",error);
3038 /* An error here doesn't warrant bringing down the device */
3044 error = sysfs_create_link(&dev->kobj,
3045 &dev->class->p->subsys.kobj,
3050 if (dev->parent && device_is_not_partition(dev)) {
3051 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3058 /* /sys/block has directories and does not need symlinks */
3059 if (sysfs_deprecated && dev->class == &block_class)
3063 /* link in the class directory pointing to the device */
3064 error = sysfs_create_link(&dev->class->p->subsys.kobj,
3065 &dev->kobj, dev_name(dev));
3072 sysfs_remove_link(&dev->kobj, "device");
3075 sysfs_remove_link(&dev->kobj, "subsystem");
3077 sysfs_remove_link(&dev->kobj, "of_node");
3081 static void device_remove_class_symlinks(struct device *dev)
3083 if (dev_of_node(dev))
3084 sysfs_remove_link(&dev->kobj, "of_node");
3089 if (dev->parent && device_is_not_partition(dev))
3090 sysfs_remove_link(&dev->kobj, "device");
3091 sysfs_remove_link(&dev->kobj, "subsystem");
3093 if (sysfs_deprecated && dev->class == &block_class)
3096 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
3100 * dev_set_name - set a device name
3102 * @fmt: format string for the device's name
3104 int dev_set_name(struct device *dev, const char *fmt, ...)
3109 va_start(vargs, fmt);
3110 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3114 EXPORT_SYMBOL_GPL(dev_set_name);
3117 * device_to_dev_kobj - select a /sys/dev/ directory for the device
3120 * By default we select char/ for new entries. Setting class->dev_obj
3121 * to NULL prevents an entry from being created. class->dev_kobj must
3122 * be set (or cleared) before any devices are registered to the class
3123 * otherwise device_create_sys_dev_entry() and
3124 * device_remove_sys_dev_entry() will disagree about the presence of
3127 static struct kobject *device_to_dev_kobj(struct device *dev)
3129 struct kobject *kobj;
3132 kobj = dev->class->dev_kobj;
3134 kobj = sysfs_dev_char_kobj;
3139 static int device_create_sys_dev_entry(struct device *dev)
3141 struct kobject *kobj = device_to_dev_kobj(dev);
3146 format_dev_t(devt_str, dev->devt);
3147 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3153 static void device_remove_sys_dev_entry(struct device *dev)
3155 struct kobject *kobj = device_to_dev_kobj(dev);
3159 format_dev_t(devt_str, dev->devt);
3160 sysfs_remove_link(kobj, devt_str);
3164 static int device_private_init(struct device *dev)
3166 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3169 dev->p->device = dev;
3170 klist_init(&dev->p->klist_children, klist_children_get,
3171 klist_children_put);
3172 INIT_LIST_HEAD(&dev->p->deferred_probe);
3177 * device_add - add device to device hierarchy.
3180 * This is part 2 of device_register(), though may be called
3181 * separately _iff_ device_initialize() has been called separately.
3183 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3184 * to the global and sibling lists for the device, then
3185 * adds it to the other relevant subsystems of the driver model.
3187 * Do not call this routine or device_register() more than once for
3188 * any device structure. The driver model core is not designed to work
3189 * with devices that get unregistered and then spring back to life.
3190 * (Among other things, it's very hard to guarantee that all references
3191 * to the previous incarnation of @dev have been dropped.) Allocate
3192 * and register a fresh new struct device instead.
3194 * NOTE: _Never_ directly free @dev after calling this function, even
3195 * if it returned an error! Always use put_device() to give up your
3196 * reference instead.
3198 * Rule of thumb is: if device_add() succeeds, you should call
3199 * device_del() when you want to get rid of it. If device_add() has
3200 * *not* succeeded, use *only* put_device() to drop the reference
3203 int device_add(struct device *dev)
3205 struct device *parent;
3206 struct kobject *kobj;
3207 struct class_interface *class_intf;
3208 int error = -EINVAL;
3209 struct kobject *glue_dir = NULL;
3211 dev = get_device(dev);
3216 error = device_private_init(dev);
3222 * for statically allocated devices, which should all be converted
3223 * some day, we need to initialize the name. We prevent reading back
3224 * the name, and force the use of dev_name()
3226 if (dev->init_name) {
3227 dev_set_name(dev, "%s", dev->init_name);
3228 dev->init_name = NULL;
3231 /* subsystems can specify simple device enumeration */
3232 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
3233 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3235 if (!dev_name(dev)) {
3240 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3242 parent = get_device(dev->parent);
3243 kobj = get_device_parent(dev, parent);
3245 error = PTR_ERR(kobj);
3249 dev->kobj.parent = kobj;
3251 /* use parent numa_node */
3252 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3253 set_dev_node(dev, dev_to_node(parent));
3255 /* first, register with generic layer. */
3256 /* we require the name to be set before, and pass NULL */
3257 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3259 glue_dir = get_glue_dir(dev);
3263 /* notify platform of device entry */
3264 error = device_platform_notify(dev, KOBJ_ADD);
3266 goto platform_error;
3268 error = device_create_file(dev, &dev_attr_uevent);
3272 error = device_add_class_symlinks(dev);
3275 error = device_add_attrs(dev);
3278 error = bus_add_device(dev);
3281 error = dpm_sysfs_add(dev);
3286 if (MAJOR(dev->devt)) {
3287 error = device_create_file(dev, &dev_attr_dev);
3291 error = device_create_sys_dev_entry(dev);
3295 devtmpfs_create_node(dev);
3298 /* Notify clients of device addition. This call must come
3299 * after dpm_sysfs_add() and before kobject_uevent().
3302 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3303 BUS_NOTIFY_ADD_DEVICE, dev);
3305 kobject_uevent(&dev->kobj, KOBJ_ADD);
3308 * Check if any of the other devices (consumers) have been waiting for
3309 * this device (supplier) to be added so that they can create a device
3312 * This needs to happen after device_pm_add() because device_link_add()
3313 * requires the supplier be registered before it's called.
3315 * But this also needs to happen before bus_probe_device() to make sure
3316 * waiting consumers can link to it before the driver is bound to the
3317 * device and the driver sync_state callback is called for this device.
3319 if (dev->fwnode && !dev->fwnode->dev) {
3320 dev->fwnode->dev = dev;
3321 fw_devlink_link_device(dev);
3324 bus_probe_device(dev);
3327 * If all driver registration is done and a newly added device doesn't
3328 * match with any driver, don't block its consumers from probing in
3329 * case the consumer device is able to operate without this supplier.
3331 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3332 fw_devlink_unblock_consumers(dev);
3335 klist_add_tail(&dev->p->knode_parent,
3336 &parent->p->klist_children);
3339 mutex_lock(&dev->class->p->mutex);
3340 /* tie the class to the device */
3341 klist_add_tail(&dev->p->knode_class,
3342 &dev->class->p->klist_devices);
3344 /* notify any interfaces that the device is here */
3345 list_for_each_entry(class_intf,
3346 &dev->class->p->interfaces, node)
3347 if (class_intf->add_dev)
3348 class_intf->add_dev(dev, class_intf);
3349 mutex_unlock(&dev->class->p->mutex);
3355 if (MAJOR(dev->devt))
3356 device_remove_file(dev, &dev_attr_dev);
3358 device_pm_remove(dev);
3359 dpm_sysfs_remove(dev);
3361 bus_remove_device(dev);
3363 device_remove_attrs(dev);
3365 device_remove_class_symlinks(dev);
3367 device_remove_file(dev, &dev_attr_uevent);
3369 device_platform_notify(dev, KOBJ_REMOVE);
3371 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3372 glue_dir = get_glue_dir(dev);
3373 kobject_del(&dev->kobj);
3375 cleanup_glue_dir(dev, glue_dir);
3383 EXPORT_SYMBOL_GPL(device_add);
3386 * device_register - register a device with the system.
3387 * @dev: pointer to the device structure
3389 * This happens in two clean steps - initialize the device
3390 * and add it to the system. The two steps can be called
3391 * separately, but this is the easiest and most common.
3392 * I.e. you should only call the two helpers separately if
3393 * have a clearly defined need to use and refcount the device
3394 * before it is added to the hierarchy.
3396 * For more information, see the kerneldoc for device_initialize()
3399 * NOTE: _Never_ directly free @dev after calling this function, even
3400 * if it returned an error! Always use put_device() to give up the
3401 * reference initialized in this function instead.
3403 int device_register(struct device *dev)
3405 device_initialize(dev);
3406 return device_add(dev);
3408 EXPORT_SYMBOL_GPL(device_register);
3411 * get_device - increment reference count for device.
3414 * This simply forwards the call to kobject_get(), though
3415 * we do take care to provide for the case that we get a NULL
3416 * pointer passed in.
3418 struct device *get_device(struct device *dev)
3420 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3422 EXPORT_SYMBOL_GPL(get_device);
3425 * put_device - decrement reference count.
3426 * @dev: device in question.
3428 void put_device(struct device *dev)
3430 /* might_sleep(); */
3432 kobject_put(&dev->kobj);
3434 EXPORT_SYMBOL_GPL(put_device);
3436 bool kill_device(struct device *dev)
3439 * Require the device lock and set the "dead" flag to guarantee that
3440 * the update behavior is consistent with the other bitfields near
3441 * it and that we cannot have an asynchronous probe routine trying
3442 * to run while we are tearing out the bus/class/sysfs from
3443 * underneath the device.
3445 lockdep_assert_held(&dev->mutex);
3449 dev->p->dead = true;
3452 EXPORT_SYMBOL_GPL(kill_device);
3455 * device_del - delete device from system.
3458 * This is the first part of the device unregistration
3459 * sequence. This removes the device from the lists we control
3460 * from here, has it removed from the other driver model
3461 * subsystems it was added to in device_add(), and removes it
3462 * from the kobject hierarchy.
3464 * NOTE: this should be called manually _iff_ device_add() was
3465 * also called manually.
3467 void device_del(struct device *dev)
3469 struct device *parent = dev->parent;
3470 struct kobject *glue_dir = NULL;
3471 struct class_interface *class_intf;
3472 unsigned int noio_flag;
3478 if (dev->fwnode && dev->fwnode->dev == dev)
3479 dev->fwnode->dev = NULL;
3481 /* Notify clients of device removal. This call must come
3482 * before dpm_sysfs_remove().
3484 noio_flag = memalloc_noio_save();
3486 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3487 BUS_NOTIFY_DEL_DEVICE, dev);
3489 dpm_sysfs_remove(dev);
3491 klist_del(&dev->p->knode_parent);
3492 if (MAJOR(dev->devt)) {
3493 devtmpfs_delete_node(dev);
3494 device_remove_sys_dev_entry(dev);
3495 device_remove_file(dev, &dev_attr_dev);
3498 device_remove_class_symlinks(dev);
3500 mutex_lock(&dev->class->p->mutex);
3501 /* notify any interfaces that the device is now gone */
3502 list_for_each_entry(class_intf,
3503 &dev->class->p->interfaces, node)
3504 if (class_intf->remove_dev)
3505 class_intf->remove_dev(dev, class_intf);
3506 /* remove the device from the class list */
3507 klist_del(&dev->p->knode_class);
3508 mutex_unlock(&dev->class->p->mutex);
3510 device_remove_file(dev, &dev_attr_uevent);
3511 device_remove_attrs(dev);
3512 bus_remove_device(dev);
3513 device_pm_remove(dev);
3514 driver_deferred_probe_del(dev);
3515 device_platform_notify(dev, KOBJ_REMOVE);
3516 device_remove_properties(dev);
3517 device_links_purge(dev);
3520 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3521 BUS_NOTIFY_REMOVED_DEVICE, dev);
3522 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3523 glue_dir = get_glue_dir(dev);
3524 kobject_del(&dev->kobj);
3525 cleanup_glue_dir(dev, glue_dir);
3526 memalloc_noio_restore(noio_flag);
3529 EXPORT_SYMBOL_GPL(device_del);
3532 * device_unregister - unregister device from system.
3533 * @dev: device going away.
3535 * We do this in two parts, like we do device_register(). First,
3536 * we remove it from all the subsystems with device_del(), then
3537 * we decrement the reference count via put_device(). If that
3538 * is the final reference count, the device will be cleaned up
3539 * via device_release() above. Otherwise, the structure will
3540 * stick around until the final reference to the device is dropped.
3542 void device_unregister(struct device *dev)
3544 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3548 EXPORT_SYMBOL_GPL(device_unregister);
3550 static struct device *prev_device(struct klist_iter *i)
3552 struct klist_node *n = klist_prev(i);
3553 struct device *dev = NULL;
3554 struct device_private *p;
3557 p = to_device_private_parent(n);
3563 static struct device *next_device(struct klist_iter *i)
3565 struct klist_node *n = klist_next(i);
3566 struct device *dev = NULL;
3567 struct device_private *p;
3570 p = to_device_private_parent(n);
3577 * device_get_devnode - path of device node file
3579 * @mode: returned file access mode
3580 * @uid: returned file owner
3581 * @gid: returned file group
3582 * @tmp: possibly allocated string
3584 * Return the relative path of a possible device node.
3585 * Non-default names may need to allocate a memory to compose
3586 * a name. This memory is returned in tmp and needs to be
3587 * freed by the caller.
3589 const char *device_get_devnode(struct device *dev,
3590 umode_t *mode, kuid_t *uid, kgid_t *gid,
3597 /* the device type may provide a specific name */
3598 if (dev->type && dev->type->devnode)
3599 *tmp = dev->type->devnode(dev, mode, uid, gid);
3603 /* the class may provide a specific name */
3604 if (dev->class && dev->class->devnode)
3605 *tmp = dev->class->devnode(dev, mode);
3609 /* return name without allocation, tmp == NULL */
3610 if (strchr(dev_name(dev), '!') == NULL)
3611 return dev_name(dev);
3613 /* replace '!' in the name with '/' */
3614 s = kstrdup(dev_name(dev), GFP_KERNEL);
3617 strreplace(s, '!', '/');
3622 * device_for_each_child - device child iterator.
3623 * @parent: parent struct device.
3624 * @fn: function to be called for each device.
3625 * @data: data for the callback.
3627 * Iterate over @parent's child devices, and call @fn for each,
3630 * We check the return of @fn each time. If it returns anything
3631 * other than 0, we break out and return that value.
3633 int device_for_each_child(struct device *parent, void *data,
3634 int (*fn)(struct device *dev, void *data))
3636 struct klist_iter i;
3637 struct device *child;
3643 klist_iter_init(&parent->p->klist_children, &i);
3644 while (!error && (child = next_device(&i)))
3645 error = fn(child, data);
3646 klist_iter_exit(&i);
3649 EXPORT_SYMBOL_GPL(device_for_each_child);
3652 * device_for_each_child_reverse - device child iterator in reversed order.
3653 * @parent: parent struct device.
3654 * @fn: function to be called for each device.
3655 * @data: data for the callback.
3657 * Iterate over @parent's child devices, and call @fn for each,
3660 * We check the return of @fn each time. If it returns anything
3661 * other than 0, we break out and return that value.
3663 int device_for_each_child_reverse(struct device *parent, void *data,
3664 int (*fn)(struct device *dev, void *data))
3666 struct klist_iter i;
3667 struct device *child;
3673 klist_iter_init(&parent->p->klist_children, &i);
3674 while ((child = prev_device(&i)) && !error)
3675 error = fn(child, data);
3676 klist_iter_exit(&i);
3679 EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3682 * device_find_child - device iterator for locating a particular device.
3683 * @parent: parent struct device
3684 * @match: Callback function to check device
3685 * @data: Data to pass to match function
3687 * This is similar to the device_for_each_child() function above, but it
3688 * returns a reference to a device that is 'found' for later use, as
3689 * determined by the @match callback.
3691 * The callback should return 0 if the device doesn't match and non-zero
3692 * if it does. If the callback returns non-zero and a reference to the
3693 * current device can be obtained, this function will return to the caller
3694 * and not iterate over any more devices.
3696 * NOTE: you will need to drop the reference with put_device() after use.
3698 struct device *device_find_child(struct device *parent, void *data,
3699 int (*match)(struct device *dev, void *data))
3701 struct klist_iter i;
3702 struct device *child;
3707 klist_iter_init(&parent->p->klist_children, &i);
3708 while ((child = next_device(&i)))
3709 if (match(child, data) && get_device(child))
3711 klist_iter_exit(&i);
3714 EXPORT_SYMBOL_GPL(device_find_child);
3717 * device_find_child_by_name - device iterator for locating a child device.
3718 * @parent: parent struct device
3719 * @name: name of the child device
3721 * This is similar to the device_find_child() function above, but it
3722 * returns a reference to a device that has the name @name.
3724 * NOTE: you will need to drop the reference with put_device() after use.
3726 struct device *device_find_child_by_name(struct device *parent,
3729 struct klist_iter i;
3730 struct device *child;
3735 klist_iter_init(&parent->p->klist_children, &i);
3736 while ((child = next_device(&i)))
3737 if (sysfs_streq(dev_name(child), name) && get_device(child))
3739 klist_iter_exit(&i);
3742 EXPORT_SYMBOL_GPL(device_find_child_by_name);
3744 int __init devices_init(void)
3746 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3749 dev_kobj = kobject_create_and_add("dev", NULL);
3752 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3753 if (!sysfs_dev_block_kobj)
3754 goto block_kobj_err;
3755 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3756 if (!sysfs_dev_char_kobj)
3762 kobject_put(sysfs_dev_block_kobj);
3764 kobject_put(dev_kobj);
3766 kset_unregister(devices_kset);
3770 static int device_check_offline(struct device *dev, void *not_used)
3774 ret = device_for_each_child(dev, NULL, device_check_offline);
3778 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3782 * device_offline - Prepare the device for hot-removal.
3783 * @dev: Device to be put offline.
3785 * Execute the device bus type's .offline() callback, if present, to prepare
3786 * the device for a subsequent hot-removal. If that succeeds, the device must
3787 * not be used until either it is removed or its bus type's .online() callback
3790 * Call under device_hotplug_lock.
3792 int device_offline(struct device *dev)
3796 if (dev->offline_disabled)
3799 ret = device_for_each_child(dev, NULL, device_check_offline);
3804 if (device_supports_offline(dev)) {
3808 ret = dev->bus->offline(dev);
3810 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3811 dev->offline = true;
3821 * device_online - Put the device back online after successful device_offline().
3822 * @dev: Device to be put back online.
3824 * If device_offline() has been successfully executed for @dev, but the device
3825 * has not been removed subsequently, execute its bus type's .online() callback
3826 * to indicate that the device can be used again.
3828 * Call under device_hotplug_lock.
3830 int device_online(struct device *dev)
3835 if (device_supports_offline(dev)) {
3837 ret = dev->bus->online(dev);
3839 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
3840 dev->offline = false;
3851 struct root_device {
3853 struct module *owner;
3856 static inline struct root_device *to_root_device(struct device *d)
3858 return container_of(d, struct root_device, dev);
3861 static void root_device_release(struct device *dev)
3863 kfree(to_root_device(dev));
3867 * __root_device_register - allocate and register a root device
3868 * @name: root device name
3869 * @owner: owner module of the root device, usually THIS_MODULE
3871 * This function allocates a root device and registers it
3872 * using device_register(). In order to free the returned
3873 * device, use root_device_unregister().
3875 * Root devices are dummy devices which allow other devices
3876 * to be grouped under /sys/devices. Use this function to
3877 * allocate a root device and then use it as the parent of
3878 * any device which should appear under /sys/devices/{name}
3880 * The /sys/devices/{name} directory will also contain a
3881 * 'module' symlink which points to the @owner directory
3884 * Returns &struct device pointer on success, or ERR_PTR() on error.
3886 * Note: You probably want to use root_device_register().
3888 struct device *__root_device_register(const char *name, struct module *owner)
3890 struct root_device *root;
3893 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
3895 return ERR_PTR(err);
3897 err = dev_set_name(&root->dev, "%s", name);
3900 return ERR_PTR(err);
3903 root->dev.release = root_device_release;
3905 err = device_register(&root->dev);
3907 put_device(&root->dev);
3908 return ERR_PTR(err);
3911 #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
3913 struct module_kobject *mk = &owner->mkobj;
3915 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
3917 device_unregister(&root->dev);
3918 return ERR_PTR(err);
3920 root->owner = owner;
3926 EXPORT_SYMBOL_GPL(__root_device_register);
3929 * root_device_unregister - unregister and free a root device
3930 * @dev: device going away
3932 * This function unregisters and cleans up a device that was created by
3933 * root_device_register().
3935 void root_device_unregister(struct device *dev)
3937 struct root_device *root = to_root_device(dev);
3940 sysfs_remove_link(&root->dev.kobj, "module");
3942 device_unregister(dev);
3944 EXPORT_SYMBOL_GPL(root_device_unregister);
3947 static void device_create_release(struct device *dev)
3949 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3953 static __printf(6, 0) struct device *
3954 device_create_groups_vargs(struct class *class, struct device *parent,
3955 dev_t devt, void *drvdata,
3956 const struct attribute_group **groups,
3957 const char *fmt, va_list args)
3959 struct device *dev = NULL;
3960 int retval = -ENODEV;
3962 if (class == NULL || IS_ERR(class))
3965 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3971 device_initialize(dev);
3974 dev->parent = parent;
3975 dev->groups = groups;
3976 dev->release = device_create_release;
3977 dev_set_drvdata(dev, drvdata);
3979 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
3983 retval = device_add(dev);
3991 return ERR_PTR(retval);
3995 * device_create - creates a device and registers it with sysfs
3996 * @class: pointer to the struct class that this device should be registered to
3997 * @parent: pointer to the parent struct device of this new device, if any
3998 * @devt: the dev_t for the char device to be added
3999 * @drvdata: the data to be added to the device for callbacks
4000 * @fmt: string for the device's name
4002 * This function can be used by char device classes. A struct device
4003 * will be created in sysfs, registered to the specified class.
4005 * A "dev" file will be created, showing the dev_t for the device, if
4006 * the dev_t is not 0,0.
4007 * If a pointer to a parent struct device is passed in, the newly created
4008 * struct device will be a child of that device in sysfs.
4009 * The pointer to the struct device will be returned from the call.
4010 * Any further sysfs files that might be required can be created using this
4013 * Returns &struct device pointer on success, or ERR_PTR() on error.
4015 * Note: the struct class passed to this function must have previously
4016 * been created with a call to class_create().
4018 struct device *device_create(struct class *class, struct device *parent,
4019 dev_t devt, void *drvdata, const char *fmt, ...)
4024 va_start(vargs, fmt);
4025 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4030 EXPORT_SYMBOL_GPL(device_create);
4033 * device_create_with_groups - creates a device and registers it with sysfs
4034 * @class: pointer to the struct class that this device should be registered to
4035 * @parent: pointer to the parent struct device of this new device, if any
4036 * @devt: the dev_t for the char device to be added
4037 * @drvdata: the data to be added to the device for callbacks
4038 * @groups: NULL-terminated list of attribute groups to be created
4039 * @fmt: string for the device's name
4041 * This function can be used by char device classes. A struct device
4042 * will be created in sysfs, registered to the specified class.
4043 * Additional attributes specified in the groups parameter will also
4044 * be created automatically.
4046 * A "dev" file will be created, showing the dev_t for the device, if
4047 * the dev_t is not 0,0.
4048 * If a pointer to a parent struct device is passed in, the newly created
4049 * struct device will be a child of that device in sysfs.
4050 * The pointer to the struct device will be returned from the call.
4051 * Any further sysfs files that might be required can be created using this
4054 * Returns &struct device pointer on success, or ERR_PTR() on error.
4056 * Note: the struct class passed to this function must have previously
4057 * been created with a call to class_create().
4059 struct device *device_create_with_groups(struct class *class,
4060 struct device *parent, dev_t devt,
4062 const struct attribute_group **groups,
4063 const char *fmt, ...)
4068 va_start(vargs, fmt);
4069 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4074 EXPORT_SYMBOL_GPL(device_create_with_groups);
4077 * device_destroy - removes a device that was created with device_create()
4078 * @class: pointer to the struct class that this device was registered with
4079 * @devt: the dev_t of the device that was previously registered
4081 * This call unregisters and cleans up a device that was created with a
4082 * call to device_create().
4084 void device_destroy(struct class *class, dev_t devt)
4088 dev = class_find_device_by_devt(class, devt);
4091 device_unregister(dev);
4094 EXPORT_SYMBOL_GPL(device_destroy);
4097 * device_rename - renames a device
4098 * @dev: the pointer to the struct device to be renamed
4099 * @new_name: the new name of the device
4101 * It is the responsibility of the caller to provide mutual
4102 * exclusion between two different calls of device_rename
4103 * on the same device to ensure that new_name is valid and
4104 * won't conflict with other devices.
4106 * Note: Don't call this function. Currently, the networking layer calls this
4107 * function, but that will change. The following text from Kay Sievers offers
4110 * Renaming devices is racy at many levels, symlinks and other stuff are not
4111 * replaced atomically, and you get a "move" uevent, but it's not easy to
4112 * connect the event to the old and new device. Device nodes are not renamed at
4113 * all, there isn't even support for that in the kernel now.
4115 * In the meantime, during renaming, your target name might be taken by another
4116 * driver, creating conflicts. Or the old name is taken directly after you
4117 * renamed it -- then you get events for the same DEVPATH, before you even see
4118 * the "move" event. It's just a mess, and nothing new should ever rely on
4119 * kernel device renaming. Besides that, it's not even implemented now for
4120 * other things than (driver-core wise very simple) network devices.
4122 * We are currently about to change network renaming in udev to completely
4123 * disallow renaming of devices in the same namespace as the kernel uses,
4124 * because we can't solve the problems properly, that arise with swapping names
4125 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
4126 * be allowed to some other name than eth[0-9]*, for the aforementioned
4129 * Make up a "real" name in the driver before you register anything, or add
4130 * some other attributes for userspace to find the device, or use udev to add
4131 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4132 * don't even want to get into that and try to implement the missing pieces in
4133 * the core. We really have other pieces to fix in the driver core mess. :)
4135 int device_rename(struct device *dev, const char *new_name)
4137 struct kobject *kobj = &dev->kobj;
4138 char *old_device_name = NULL;
4141 dev = get_device(dev);
4145 dev_dbg(dev, "renaming to %s\n", new_name);
4147 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4148 if (!old_device_name) {
4154 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
4155 kobj, old_device_name,
4156 new_name, kobject_namespace(kobj));
4161 error = kobject_rename(kobj, new_name);
4168 kfree(old_device_name);
4172 EXPORT_SYMBOL_GPL(device_rename);
4174 static int device_move_class_links(struct device *dev,
4175 struct device *old_parent,
4176 struct device *new_parent)
4181 sysfs_remove_link(&dev->kobj, "device");
4183 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4189 * device_move - moves a device to a new parent
4190 * @dev: the pointer to the struct device to be moved
4191 * @new_parent: the new parent of the device (can be NULL)
4192 * @dpm_order: how to reorder the dpm_list
4194 int device_move(struct device *dev, struct device *new_parent,
4195 enum dpm_order dpm_order)
4198 struct device *old_parent;
4199 struct kobject *new_parent_kobj;
4201 dev = get_device(dev);
4206 new_parent = get_device(new_parent);
4207 new_parent_kobj = get_device_parent(dev, new_parent);
4208 if (IS_ERR(new_parent_kobj)) {
4209 error = PTR_ERR(new_parent_kobj);
4210 put_device(new_parent);
4214 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4215 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4216 error = kobject_move(&dev->kobj, new_parent_kobj);
4218 cleanup_glue_dir(dev, new_parent_kobj);
4219 put_device(new_parent);
4222 old_parent = dev->parent;
4223 dev->parent = new_parent;
4225 klist_remove(&dev->p->knode_parent);
4227 klist_add_tail(&dev->p->knode_parent,
4228 &new_parent->p->klist_children);
4229 set_dev_node(dev, dev_to_node(new_parent));
4233 error = device_move_class_links(dev, old_parent, new_parent);
4235 /* We ignore errors on cleanup since we're hosed anyway... */
4236 device_move_class_links(dev, new_parent, old_parent);
4237 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4239 klist_remove(&dev->p->knode_parent);
4240 dev->parent = old_parent;
4242 klist_add_tail(&dev->p->knode_parent,
4243 &old_parent->p->klist_children);
4244 set_dev_node(dev, dev_to_node(old_parent));
4247 cleanup_glue_dir(dev, new_parent_kobj);
4248 put_device(new_parent);
4252 switch (dpm_order) {
4253 case DPM_ORDER_NONE:
4255 case DPM_ORDER_DEV_AFTER_PARENT:
4256 device_pm_move_after(dev, new_parent);
4257 devices_kset_move_after(dev, new_parent);
4259 case DPM_ORDER_PARENT_BEFORE_DEV:
4260 device_pm_move_before(new_parent, dev);
4261 devices_kset_move_before(new_parent, dev);
4263 case DPM_ORDER_DEV_LAST:
4264 device_pm_move_last(dev);
4265 devices_kset_move_last(dev);
4269 put_device(old_parent);
4275 EXPORT_SYMBOL_GPL(device_move);
4277 static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4280 struct kobject *kobj = &dev->kobj;
4281 struct class *class = dev->class;
4282 const struct device_type *type = dev->type;
4287 * Change the device groups of the device class for @dev to
4290 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4298 * Change the device groups of the device type for @dev to
4301 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4307 /* Change the device groups of @dev to @kuid/@kgid. */
4308 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4312 if (device_supports_offline(dev) && !dev->offline_disabled) {
4313 /* Change online device attributes of @dev to @kuid/@kgid. */
4314 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4324 * device_change_owner - change the owner of an existing device.
4326 * @kuid: new owner's kuid
4327 * @kgid: new owner's kgid
4329 * This changes the owner of @dev and its corresponding sysfs entries to
4330 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4333 * Returns 0 on success or error code on failure.
4335 int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4338 struct kobject *kobj = &dev->kobj;
4340 dev = get_device(dev);
4345 * Change the kobject and the default attributes and groups of the
4346 * ktype associated with it to @kuid/@kgid.
4348 error = sysfs_change_owner(kobj, kuid, kgid);
4353 * Change the uevent file for @dev to the new owner. The uevent file
4354 * was created in a separate step when @dev got added and we mirror
4357 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4363 * Change the device groups, the device groups associated with the
4364 * device class, and the groups associated with the device type of @dev
4367 error = device_attrs_change_owner(dev, kuid, kgid);
4371 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4376 if (sysfs_deprecated && dev->class == &block_class)
4381 * Change the owner of the symlink located in the class directory of
4382 * the device class associated with @dev which points to the actual
4383 * directory entry for @dev to @kuid/@kgid. This ensures that the
4384 * symlink shows the same permissions as its target.
4386 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
4387 dev_name(dev), kuid, kgid);
4395 EXPORT_SYMBOL_GPL(device_change_owner);
4398 * device_shutdown - call ->shutdown() on each device to shutdown.
4400 void device_shutdown(void)
4402 struct device *dev, *parent;
4404 wait_for_device_probe();
4405 device_block_probing();
4409 spin_lock(&devices_kset->list_lock);
4411 * Walk the devices list backward, shutting down each in turn.
4412 * Beware that device unplug events may also start pulling
4413 * devices offline, even as the system is shutting down.
4415 while (!list_empty(&devices_kset->list)) {
4416 dev = list_entry(devices_kset->list.prev, struct device,
4420 * hold reference count of device's parent to
4421 * prevent it from being freed because parent's
4422 * lock is to be held
4424 parent = get_device(dev->parent);
4427 * Make sure the device is off the kset list, in the
4428 * event that dev->*->shutdown() doesn't remove it.
4430 list_del_init(&dev->kobj.entry);
4431 spin_unlock(&devices_kset->list_lock);
4433 /* hold lock to avoid race with probe/release */
4435 device_lock(parent);
4438 /* Don't allow any more runtime suspends */
4439 pm_runtime_get_noresume(dev);
4440 pm_runtime_barrier(dev);
4442 if (dev->class && dev->class->shutdown_pre) {
4444 dev_info(dev, "shutdown_pre\n");
4445 dev->class->shutdown_pre(dev);
4447 if (dev->bus && dev->bus->shutdown) {
4449 dev_info(dev, "shutdown\n");
4450 dev->bus->shutdown(dev);
4451 } else if (dev->driver && dev->driver->shutdown) {
4453 dev_info(dev, "shutdown\n");
4454 dev->driver->shutdown(dev);
4459 device_unlock(parent);
4464 spin_lock(&devices_kset->list_lock);
4466 spin_unlock(&devices_kset->list_lock);
4470 * Device logging functions
4473 #ifdef CONFIG_PRINTK
4475 set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4479 memset(dev_info, 0, sizeof(*dev_info));
4482 subsys = dev->class->name;
4484 subsys = dev->bus->name;
4488 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4491 * Add device identifier DEVICE=:
4495 * +sound:card0 subsystem:devname
4497 if (MAJOR(dev->devt)) {
4500 if (strcmp(subsys, "block") == 0)
4505 snprintf(dev_info->device, sizeof(dev_info->device),
4506 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4507 } else if (strcmp(subsys, "net") == 0) {
4508 struct net_device *net = to_net_dev(dev);
4510 snprintf(dev_info->device, sizeof(dev_info->device),
4511 "n%u", net->ifindex);
4513 snprintf(dev_info->device, sizeof(dev_info->device),
4514 "+%s:%s", subsys, dev_name(dev));
4518 int dev_vprintk_emit(int level, const struct device *dev,
4519 const char *fmt, va_list args)
4521 struct dev_printk_info dev_info;
4523 set_dev_info(dev, &dev_info);
4525 return vprintk_emit(0, level, &dev_info, fmt, args);
4527 EXPORT_SYMBOL(dev_vprintk_emit);
4529 int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4534 va_start(args, fmt);
4536 r = dev_vprintk_emit(level, dev, fmt, args);
4542 EXPORT_SYMBOL(dev_printk_emit);
4544 static void __dev_printk(const char *level, const struct device *dev,
4545 struct va_format *vaf)
4548 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4549 dev_driver_string(dev), dev_name(dev), vaf);
4551 printk("%s(NULL device *): %pV", level, vaf);
4554 void dev_printk(const char *level, const struct device *dev,
4555 const char *fmt, ...)
4557 struct va_format vaf;
4560 va_start(args, fmt);
4565 __dev_printk(level, dev, &vaf);
4569 EXPORT_SYMBOL(dev_printk);
4571 #define define_dev_printk_level(func, kern_level) \
4572 void func(const struct device *dev, const char *fmt, ...) \
4574 struct va_format vaf; \
4577 va_start(args, fmt); \
4582 __dev_printk(kern_level, dev, &vaf); \
4586 EXPORT_SYMBOL(func);
4588 define_dev_printk_level(_dev_emerg, KERN_EMERG);
4589 define_dev_printk_level(_dev_alert, KERN_ALERT);
4590 define_dev_printk_level(_dev_crit, KERN_CRIT);
4591 define_dev_printk_level(_dev_err, KERN_ERR);
4592 define_dev_printk_level(_dev_warn, KERN_WARNING);
4593 define_dev_printk_level(_dev_notice, KERN_NOTICE);
4594 define_dev_printk_level(_dev_info, KERN_INFO);
4599 * dev_err_probe - probe error check and log helper
4600 * @dev: the pointer to the struct device
4601 * @err: error value to test
4602 * @fmt: printf-style format string
4603 * @...: arguments as specified in the format string
4605 * This helper implements common pattern present in probe functions for error
4606 * checking: print debug or error message depending if the error value is
4607 * -EPROBE_DEFER and propagate error upwards.
4608 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4609 * checked later by reading devices_deferred debugfs attribute.
4610 * It replaces code sequence::
4612 * if (err != -EPROBE_DEFER)
4613 * dev_err(dev, ...);
4615 * dev_dbg(dev, ...);
4620 * return dev_err_probe(dev, err, ...);
4625 int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4627 struct va_format vaf;
4630 va_start(args, fmt);
4634 if (err != -EPROBE_DEFER) {
4635 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4637 device_set_deferred_probe_reason(dev, &vaf);
4638 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4645 EXPORT_SYMBOL_GPL(dev_err_probe);
4647 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4649 return fwnode && !IS_ERR(fwnode->secondary);
4653 * set_primary_fwnode - Change the primary firmware node of a given device.
4654 * @dev: Device to handle.
4655 * @fwnode: New primary firmware node of the device.
4657 * Set the device's firmware node pointer to @fwnode, but if a secondary
4658 * firmware node of the device is present, preserve it.
4660 * Valid fwnode cases are:
4661 * - primary --> secondary --> -ENODEV
4662 * - primary --> NULL
4663 * - secondary --> -ENODEV
4666 void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4668 struct device *parent = dev->parent;
4669 struct fwnode_handle *fn = dev->fwnode;
4672 if (fwnode_is_primary(fn))
4676 WARN_ON(fwnode->secondary);
4677 fwnode->secondary = fn;
4679 dev->fwnode = fwnode;
4681 if (fwnode_is_primary(fn)) {
4682 dev->fwnode = fn->secondary;
4683 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
4684 if (!(parent && fn == parent->fwnode))
4685 fn->secondary = NULL;
4691 EXPORT_SYMBOL_GPL(set_primary_fwnode);
4694 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4695 * @dev: Device to handle.
4696 * @fwnode: New secondary firmware node of the device.
4698 * If a primary firmware node of the device is present, set its secondary
4699 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4702 void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4705 fwnode->secondary = ERR_PTR(-ENODEV);
4707 if (fwnode_is_primary(dev->fwnode))
4708 dev->fwnode->secondary = fwnode;
4710 dev->fwnode = fwnode;
4712 EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4715 * device_set_of_node_from_dev - reuse device-tree node of another device
4716 * @dev: device whose device-tree node is being set
4717 * @dev2: device whose device-tree node is being reused
4719 * Takes another reference to the new device-tree node after first dropping
4720 * any reference held to the old node.
4722 void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4724 of_node_put(dev->of_node);
4725 dev->of_node = of_node_get(dev2->of_node);
4726 dev->of_node_reused = true;
4728 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4730 int device_match_name(struct device *dev, const void *name)
4732 return sysfs_streq(dev_name(dev), name);
4734 EXPORT_SYMBOL_GPL(device_match_name);
4736 int device_match_of_node(struct device *dev, const void *np)
4738 return dev->of_node == np;
4740 EXPORT_SYMBOL_GPL(device_match_of_node);
4742 int device_match_fwnode(struct device *dev, const void *fwnode)
4744 return dev_fwnode(dev) == fwnode;
4746 EXPORT_SYMBOL_GPL(device_match_fwnode);
4748 int device_match_devt(struct device *dev, const void *pdevt)
4750 return dev->devt == *(dev_t *)pdevt;
4752 EXPORT_SYMBOL_GPL(device_match_devt);
4754 int device_match_acpi_dev(struct device *dev, const void *adev)
4756 return ACPI_COMPANION(dev) == adev;
4758 EXPORT_SYMBOL(device_match_acpi_dev);
4760 int device_match_any(struct device *dev, const void *unused)
4764 EXPORT_SYMBOL_GPL(device_match_any);