1 // SPDX-License-Identifier: GPL-2.0
3 * drivers/base/core.c - core driver model code (device registration, etc)
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (c) 2006 Novell, Inc.
11 #include <linux/acpi.h>
12 #include <linux/cpufreq.h>
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/fwnode.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/string.h>
20 #include <linux/kdev_t.h>
21 #include <linux/notifier.h>
23 #include <linux/of_device.h>
24 #include <linux/genhd.h>
25 #include <linux/mutex.h>
26 #include <linux/pm_runtime.h>
27 #include <linux/netdevice.h>
28 #include <linux/sched/signal.h>
29 #include <linux/sched/mm.h>
30 #include <linux/swiotlb.h>
31 #include <linux/sysfs.h>
32 #include <linux/dma-map-ops.h> /* for dma_default_coherent */
35 #include "power/power.h"
37 #ifdef CONFIG_SYSFS_DEPRECATED
38 #ifdef CONFIG_SYSFS_DEPRECATED_V2
39 long sysfs_deprecated = 1;
41 long sysfs_deprecated = 0;
43 static int __init sysfs_deprecated_setup(char *arg)
45 return kstrtol(arg, 10, &sysfs_deprecated);
47 early_param("sysfs.deprecated", sysfs_deprecated_setup);
50 /* Device links support. */
51 static LIST_HEAD(deferred_sync);
52 static unsigned int defer_sync_state_count = 1;
53 static DEFINE_MUTEX(fwnode_link_lock);
54 static bool fw_devlink_is_permissive(void);
55 static bool fw_devlink_drv_reg_done;
58 * fwnode_link_add - Create a link between two fwnode_handles.
59 * @con: Consumer end of the link.
60 * @sup: Supplier end of the link.
62 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
63 * represents the detail that the firmware lists @sup fwnode as supplying a
66 * The driver core will use the fwnode link to create a device link between the
67 * two device objects corresponding to @con and @sup when they are created. The
68 * driver core will automatically delete the fwnode link between @con and @sup
71 * Attempts to create duplicate links between the same pair of fwnode handles
72 * are ignored and there is no reference counting.
74 int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
76 struct fwnode_link *link;
79 mutex_lock(&fwnode_link_lock);
81 list_for_each_entry(link, &sup->consumers, s_hook)
82 if (link->consumer == con)
85 link = kzalloc(sizeof(*link), GFP_KERNEL);
92 INIT_LIST_HEAD(&link->s_hook);
94 INIT_LIST_HEAD(&link->c_hook);
96 list_add(&link->s_hook, &sup->consumers);
97 list_add(&link->c_hook, &con->suppliers);
98 pr_debug("%pfwP Linked as a fwnode consumer to %pfwP\n",
101 mutex_unlock(&fwnode_link_lock);
107 * __fwnode_link_del - Delete a link between two fwnode_handles.
108 * @link: the fwnode_link to be deleted
110 * The fwnode_link_lock needs to be held when this function is called.
112 static void __fwnode_link_del(struct fwnode_link *link)
114 pr_debug("%pfwP Dropping the fwnode link to %pfwP\n",
115 link->consumer, link->supplier);
116 list_del(&link->s_hook);
117 list_del(&link->c_hook);
122 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
123 * @fwnode: fwnode whose supplier links need to be deleted
125 * Deletes all supplier links connecting directly to @fwnode.
127 static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
129 struct fwnode_link *link, *tmp;
131 mutex_lock(&fwnode_link_lock);
132 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
133 __fwnode_link_del(link);
134 mutex_unlock(&fwnode_link_lock);
138 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
139 * @fwnode: fwnode whose consumer links need to be deleted
141 * Deletes all consumer links connecting directly to @fwnode.
143 static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
145 struct fwnode_link *link, *tmp;
147 mutex_lock(&fwnode_link_lock);
148 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
149 __fwnode_link_del(link);
150 mutex_unlock(&fwnode_link_lock);
154 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
155 * @fwnode: fwnode whose links needs to be deleted
157 * Deletes all links connecting directly to a fwnode.
159 void fwnode_links_purge(struct fwnode_handle *fwnode)
161 fwnode_links_purge_suppliers(fwnode);
162 fwnode_links_purge_consumers(fwnode);
165 void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
167 struct fwnode_handle *child;
169 /* Don't purge consumer links of an added child */
173 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
174 fwnode_links_purge_consumers(fwnode);
176 fwnode_for_each_available_child_node(fwnode, child)
177 fw_devlink_purge_absent_suppliers(child);
179 EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
182 static DEFINE_MUTEX(device_links_lock);
183 DEFINE_STATIC_SRCU(device_links_srcu);
185 static inline void device_links_write_lock(void)
187 mutex_lock(&device_links_lock);
190 static inline void device_links_write_unlock(void)
192 mutex_unlock(&device_links_lock);
195 int device_links_read_lock(void) __acquires(&device_links_srcu)
197 return srcu_read_lock(&device_links_srcu);
200 void device_links_read_unlock(int idx) __releases(&device_links_srcu)
202 srcu_read_unlock(&device_links_srcu, idx);
205 int device_links_read_lock_held(void)
207 return srcu_read_lock_held(&device_links_srcu);
210 static void device_link_synchronize_removal(void)
212 synchronize_srcu(&device_links_srcu);
215 static void device_link_remove_from_lists(struct device_link *link)
217 list_del_rcu(&link->s_node);
218 list_del_rcu(&link->c_node);
220 #else /* !CONFIG_SRCU */
221 static DECLARE_RWSEM(device_links_lock);
223 static inline void device_links_write_lock(void)
225 down_write(&device_links_lock);
228 static inline void device_links_write_unlock(void)
230 up_write(&device_links_lock);
233 int device_links_read_lock(void)
235 down_read(&device_links_lock);
239 void device_links_read_unlock(int not_used)
241 up_read(&device_links_lock);
244 #ifdef CONFIG_DEBUG_LOCK_ALLOC
245 int device_links_read_lock_held(void)
247 return lockdep_is_held(&device_links_lock);
251 static inline void device_link_synchronize_removal(void)
255 static void device_link_remove_from_lists(struct device_link *link)
257 list_del(&link->s_node);
258 list_del(&link->c_node);
260 #endif /* !CONFIG_SRCU */
262 static bool device_is_ancestor(struct device *dev, struct device *target)
264 while (target->parent) {
265 target = target->parent;
273 * device_is_dependent - Check if one device depends on another one
274 * @dev: Device to check dependencies for.
275 * @target: Device to check against.
277 * Check if @target depends on @dev or any device dependent on it (its child or
278 * its consumer etc). Return 1 if that is the case or 0 otherwise.
280 int device_is_dependent(struct device *dev, void *target)
282 struct device_link *link;
286 * The "ancestors" check is needed to catch the case when the target
287 * device has not been completely initialized yet and it is still
288 * missing from the list of children of its parent device.
290 if (dev == target || device_is_ancestor(dev, target))
293 ret = device_for_each_child(dev, target, device_is_dependent);
297 list_for_each_entry(link, &dev->links.consumers, s_node) {
298 if ((link->flags & ~DL_FLAG_INFERRED) ==
299 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
302 if (link->consumer == target)
305 ret = device_is_dependent(link->consumer, target);
312 static void device_link_init_status(struct device_link *link,
313 struct device *consumer,
314 struct device *supplier)
316 switch (supplier->links.status) {
318 switch (consumer->links.status) {
321 * A consumer driver can create a link to a supplier
322 * that has not completed its probing yet as long as it
323 * knows that the supplier is already functional (for
324 * example, it has just acquired some resources from the
327 link->status = DL_STATE_CONSUMER_PROBE;
330 link->status = DL_STATE_DORMANT;
334 case DL_DEV_DRIVER_BOUND:
335 switch (consumer->links.status) {
337 link->status = DL_STATE_CONSUMER_PROBE;
339 case DL_DEV_DRIVER_BOUND:
340 link->status = DL_STATE_ACTIVE;
343 link->status = DL_STATE_AVAILABLE;
347 case DL_DEV_UNBINDING:
348 link->status = DL_STATE_SUPPLIER_UNBIND;
351 link->status = DL_STATE_DORMANT;
356 static int device_reorder_to_tail(struct device *dev, void *not_used)
358 struct device_link *link;
361 * Devices that have not been registered yet will be put to the ends
362 * of the lists during the registration, so skip them here.
364 if (device_is_registered(dev))
365 devices_kset_move_last(dev);
367 if (device_pm_initialized(dev))
368 device_pm_move_last(dev);
370 device_for_each_child(dev, NULL, device_reorder_to_tail);
371 list_for_each_entry(link, &dev->links.consumers, s_node) {
372 if ((link->flags & ~DL_FLAG_INFERRED) ==
373 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
375 device_reorder_to_tail(link->consumer, NULL);
382 * device_pm_move_to_tail - Move set of devices to the end of device lists
383 * @dev: Device to move
385 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
387 * It moves the @dev along with all of its children and all of its consumers
388 * to the ends of the device_kset and dpm_list, recursively.
390 void device_pm_move_to_tail(struct device *dev)
394 idx = device_links_read_lock();
396 device_reorder_to_tail(dev, NULL);
398 device_links_read_unlock(idx);
401 #define to_devlink(dev) container_of((dev), struct device_link, link_dev)
403 static ssize_t status_show(struct device *dev,
404 struct device_attribute *attr, char *buf)
408 switch (to_devlink(dev)->status) {
410 output = "not tracked";
412 case DL_STATE_DORMANT:
415 case DL_STATE_AVAILABLE:
416 output = "available";
418 case DL_STATE_CONSUMER_PROBE:
419 output = "consumer probing";
421 case DL_STATE_ACTIVE:
424 case DL_STATE_SUPPLIER_UNBIND:
425 output = "supplier unbinding";
432 return sysfs_emit(buf, "%s\n", output);
434 static DEVICE_ATTR_RO(status);
436 static ssize_t auto_remove_on_show(struct device *dev,
437 struct device_attribute *attr, char *buf)
439 struct device_link *link = to_devlink(dev);
442 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
443 output = "supplier unbind";
444 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
445 output = "consumer unbind";
449 return sysfs_emit(buf, "%s\n", output);
451 static DEVICE_ATTR_RO(auto_remove_on);
453 static ssize_t runtime_pm_show(struct device *dev,
454 struct device_attribute *attr, char *buf)
456 struct device_link *link = to_devlink(dev);
458 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
460 static DEVICE_ATTR_RO(runtime_pm);
462 static ssize_t sync_state_only_show(struct device *dev,
463 struct device_attribute *attr, char *buf)
465 struct device_link *link = to_devlink(dev);
467 return sysfs_emit(buf, "%d\n",
468 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
470 static DEVICE_ATTR_RO(sync_state_only);
472 static struct attribute *devlink_attrs[] = {
473 &dev_attr_status.attr,
474 &dev_attr_auto_remove_on.attr,
475 &dev_attr_runtime_pm.attr,
476 &dev_attr_sync_state_only.attr,
479 ATTRIBUTE_GROUPS(devlink);
481 static void device_link_release_fn(struct work_struct *work)
483 struct device_link *link = container_of(work, struct device_link, rm_work);
485 /* Ensure that all references to the link object have been dropped. */
486 device_link_synchronize_removal();
488 pm_runtime_release_supplier(link, true);
490 put_device(link->consumer);
491 put_device(link->supplier);
495 static void devlink_dev_release(struct device *dev)
497 struct device_link *link = to_devlink(dev);
499 INIT_WORK(&link->rm_work, device_link_release_fn);
501 * It may take a while to complete this work because of the SRCU
502 * synchronization in device_link_release_fn() and if the consumer or
503 * supplier devices get deleted when it runs, so put it into the "long"
506 queue_work(system_long_wq, &link->rm_work);
509 static struct class devlink_class = {
511 .owner = THIS_MODULE,
512 .dev_groups = devlink_groups,
513 .dev_release = devlink_dev_release,
516 static int devlink_add_symlinks(struct device *dev,
517 struct class_interface *class_intf)
521 struct device_link *link = to_devlink(dev);
522 struct device *sup = link->supplier;
523 struct device *con = link->consumer;
526 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
527 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
529 len += strlen("supplier:") + 1;
530 buf = kzalloc(len, GFP_KERNEL);
534 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
538 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
542 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
543 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
547 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
548 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
555 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
556 sysfs_remove_link(&sup->kobj, buf);
558 sysfs_remove_link(&link->link_dev.kobj, "consumer");
560 sysfs_remove_link(&link->link_dev.kobj, "supplier");
566 static void devlink_remove_symlinks(struct device *dev,
567 struct class_interface *class_intf)
569 struct device_link *link = to_devlink(dev);
571 struct device *sup = link->supplier;
572 struct device *con = link->consumer;
575 sysfs_remove_link(&link->link_dev.kobj, "consumer");
576 sysfs_remove_link(&link->link_dev.kobj, "supplier");
578 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
579 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
581 len += strlen("supplier:") + 1;
582 buf = kzalloc(len, GFP_KERNEL);
584 WARN(1, "Unable to properly free device link symlinks!\n");
588 if (device_is_registered(con)) {
589 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
590 sysfs_remove_link(&con->kobj, buf);
592 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
593 sysfs_remove_link(&sup->kobj, buf);
597 static struct class_interface devlink_class_intf = {
598 .class = &devlink_class,
599 .add_dev = devlink_add_symlinks,
600 .remove_dev = devlink_remove_symlinks,
603 static int __init devlink_class_init(void)
607 ret = class_register(&devlink_class);
611 ret = class_interface_register(&devlink_class_intf);
613 class_unregister(&devlink_class);
617 postcore_initcall(devlink_class_init);
619 #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
620 DL_FLAG_AUTOREMOVE_SUPPLIER | \
621 DL_FLAG_AUTOPROBE_CONSUMER | \
622 DL_FLAG_SYNC_STATE_ONLY | \
625 #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
626 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
629 * device_link_add - Create a link between two devices.
630 * @consumer: Consumer end of the link.
631 * @supplier: Supplier end of the link.
632 * @flags: Link flags.
634 * The caller is responsible for the proper synchronization of the link creation
635 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
636 * runtime PM framework to take the link into account. Second, if the
637 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
638 * be forced into the active meta state and reference-counted upon the creation
639 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
642 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
643 * expected to release the link returned by it directly with the help of either
644 * device_link_del() or device_link_remove().
646 * If that flag is not set, however, the caller of this function is handing the
647 * management of the link over to the driver core entirely and its return value
648 * can only be used to check whether or not the link is present. In that case,
649 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
650 * flags can be used to indicate to the driver core when the link can be safely
651 * deleted. Namely, setting one of them in @flags indicates to the driver core
652 * that the link is not going to be used (by the given caller of this function)
653 * after unbinding the consumer or supplier driver, respectively, from its
654 * device, so the link can be deleted at that point. If none of them is set,
655 * the link will be maintained until one of the devices pointed to by it (either
656 * the consumer or the supplier) is unregistered.
658 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
659 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
660 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
661 * be used to request the driver core to automatically probe for a consumer
662 * driver after successfully binding a driver to the supplier device.
664 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
665 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
666 * the same time is invalid and will cause NULL to be returned upfront.
667 * However, if a device link between the given @consumer and @supplier pair
668 * exists already when this function is called for them, the existing link will
669 * be returned regardless of its current type and status (the link's flags may
670 * be modified then). The caller of this function is then expected to treat
671 * the link as though it has just been created, so (in particular) if
672 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
673 * explicitly when not needed any more (as stated above).
675 * A side effect of the link creation is re-ordering of dpm_list and the
676 * devices_kset list by moving the consumer device and all devices depending
677 * on it to the ends of these lists (that does not happen to devices that have
678 * not been registered when this function is called).
680 * The supplier device is required to be registered when this function is called
681 * and NULL will be returned if that is not the case. The consumer device need
682 * not be registered, however.
684 struct device_link *device_link_add(struct device *consumer,
685 struct device *supplier, u32 flags)
687 struct device_link *link;
689 if (!consumer || !supplier || consumer == supplier ||
690 flags & ~DL_ADD_VALID_FLAGS ||
691 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
692 (flags & DL_FLAG_SYNC_STATE_ONLY &&
693 (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) ||
694 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
695 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
696 DL_FLAG_AUTOREMOVE_SUPPLIER)))
699 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
700 if (pm_runtime_get_sync(supplier) < 0) {
701 pm_runtime_put_noidle(supplier);
706 if (!(flags & DL_FLAG_STATELESS))
707 flags |= DL_FLAG_MANAGED;
709 device_links_write_lock();
713 * If the supplier has not been fully registered yet or there is a
714 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
715 * the supplier already in the graph, return NULL. If the link is a
716 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
717 * because it only affects sync_state() callbacks.
719 if (!device_pm_initialized(supplier)
720 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
721 device_is_dependent(consumer, supplier))) {
727 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
728 * So, only create it if the consumer hasn't probed yet.
730 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
731 consumer->links.status != DL_DEV_NO_DRIVER &&
732 consumer->links.status != DL_DEV_PROBING) {
738 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
739 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
740 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
742 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
743 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
745 list_for_each_entry(link, &supplier->links.consumers, s_node) {
746 if (link->consumer != consumer)
749 if (link->flags & DL_FLAG_INFERRED &&
750 !(flags & DL_FLAG_INFERRED))
751 link->flags &= ~DL_FLAG_INFERRED;
753 if (flags & DL_FLAG_PM_RUNTIME) {
754 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
755 pm_runtime_new_link(consumer);
756 link->flags |= DL_FLAG_PM_RUNTIME;
758 if (flags & DL_FLAG_RPM_ACTIVE)
759 refcount_inc(&link->rpm_active);
762 if (flags & DL_FLAG_STATELESS) {
763 kref_get(&link->kref);
764 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
765 !(link->flags & DL_FLAG_STATELESS)) {
766 link->flags |= DL_FLAG_STATELESS;
769 link->flags |= DL_FLAG_STATELESS;
775 * If the life time of the link following from the new flags is
776 * longer than indicated by the flags of the existing link,
777 * update the existing link to stay around longer.
779 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
780 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
781 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
782 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
784 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
785 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
786 DL_FLAG_AUTOREMOVE_SUPPLIER);
788 if (!(link->flags & DL_FLAG_MANAGED)) {
789 kref_get(&link->kref);
790 link->flags |= DL_FLAG_MANAGED;
791 device_link_init_status(link, consumer, supplier);
793 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
794 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
795 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
802 link = kzalloc(sizeof(*link), GFP_KERNEL);
806 refcount_set(&link->rpm_active, 1);
808 get_device(supplier);
809 link->supplier = supplier;
810 INIT_LIST_HEAD(&link->s_node);
811 get_device(consumer);
812 link->consumer = consumer;
813 INIT_LIST_HEAD(&link->c_node);
815 kref_init(&link->kref);
817 link->link_dev.class = &devlink_class;
818 device_set_pm_not_required(&link->link_dev);
819 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
820 dev_bus_name(supplier), dev_name(supplier),
821 dev_bus_name(consumer), dev_name(consumer));
822 if (device_register(&link->link_dev)) {
823 put_device(&link->link_dev);
828 if (flags & DL_FLAG_PM_RUNTIME) {
829 if (flags & DL_FLAG_RPM_ACTIVE)
830 refcount_inc(&link->rpm_active);
832 pm_runtime_new_link(consumer);
835 /* Determine the initial link state. */
836 if (flags & DL_FLAG_STATELESS)
837 link->status = DL_STATE_NONE;
839 device_link_init_status(link, consumer, supplier);
842 * Some callers expect the link creation during consumer driver probe to
843 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
845 if (link->status == DL_STATE_CONSUMER_PROBE &&
846 flags & DL_FLAG_PM_RUNTIME)
847 pm_runtime_resume(supplier);
849 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
850 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
852 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
854 "Linked as a sync state only consumer to %s\n",
861 * Move the consumer and all of the devices depending on it to the end
862 * of dpm_list and the devices_kset list.
864 * It is necessary to hold dpm_list locked throughout all that or else
865 * we may end up suspending with a wrong ordering of it.
867 device_reorder_to_tail(consumer, NULL);
869 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
873 device_links_write_unlock();
875 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
876 pm_runtime_put(supplier);
880 EXPORT_SYMBOL_GPL(device_link_add);
882 static void __device_link_del(struct kref *kref)
884 struct device_link *link = container_of(kref, struct device_link, kref);
886 dev_dbg(link->consumer, "Dropping the link to %s\n",
887 dev_name(link->supplier));
889 pm_runtime_drop_link(link);
891 device_link_remove_from_lists(link);
892 device_unregister(&link->link_dev);
895 static void device_link_put_kref(struct device_link *link)
897 if (link->flags & DL_FLAG_STATELESS)
898 kref_put(&link->kref, __device_link_del);
899 else if (!device_is_registered(link->consumer))
900 __device_link_del(&link->kref);
902 WARN(1, "Unable to drop a managed device link reference\n");
906 * device_link_del - Delete a stateless link between two devices.
907 * @link: Device link to delete.
909 * The caller must ensure proper synchronization of this function with runtime
910 * PM. If the link was added multiple times, it needs to be deleted as often.
911 * Care is required for hotplugged devices: Their links are purged on removal
912 * and calling device_link_del() is then no longer allowed.
914 void device_link_del(struct device_link *link)
916 device_links_write_lock();
917 device_link_put_kref(link);
918 device_links_write_unlock();
920 EXPORT_SYMBOL_GPL(device_link_del);
923 * device_link_remove - Delete a stateless link between two devices.
924 * @consumer: Consumer end of the link.
925 * @supplier: Supplier end of the link.
927 * The caller must ensure proper synchronization of this function with runtime
930 void device_link_remove(void *consumer, struct device *supplier)
932 struct device_link *link;
934 if (WARN_ON(consumer == supplier))
937 device_links_write_lock();
939 list_for_each_entry(link, &supplier->links.consumers, s_node) {
940 if (link->consumer == consumer) {
941 device_link_put_kref(link);
946 device_links_write_unlock();
948 EXPORT_SYMBOL_GPL(device_link_remove);
950 static void device_links_missing_supplier(struct device *dev)
952 struct device_link *link;
954 list_for_each_entry(link, &dev->links.suppliers, c_node) {
955 if (link->status != DL_STATE_CONSUMER_PROBE)
958 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
959 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
961 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
962 WRITE_ONCE(link->status, DL_STATE_DORMANT);
968 * device_links_check_suppliers - Check presence of supplier drivers.
969 * @dev: Consumer device.
971 * Check links from this device to any suppliers. Walk the list of the device's
972 * links to suppliers and see if all of them are available. If not, simply
973 * return -EPROBE_DEFER.
975 * We need to guarantee that the supplier will not go away after the check has
976 * been positive here. It only can go away in __device_release_driver() and
977 * that function checks the device's links to consumers. This means we need to
978 * mark the link as "consumer probe in progress" to make the supplier removal
979 * wait for us to complete (or bad things may happen).
981 * Links without the DL_FLAG_MANAGED flag set are ignored.
983 int device_links_check_suppliers(struct device *dev)
985 struct device_link *link;
987 struct fwnode_handle *sup_fw;
990 * Device waiting for supplier to become available is not allowed to
993 mutex_lock(&fwnode_link_lock);
994 if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
995 !fw_devlink_is_permissive()) {
996 sup_fw = list_first_entry(&dev->fwnode->suppliers,
999 dev_err_probe(dev, -EPROBE_DEFER, "wait for supplier %pfwP\n",
1001 mutex_unlock(&fwnode_link_lock);
1002 return -EPROBE_DEFER;
1004 mutex_unlock(&fwnode_link_lock);
1006 device_links_write_lock();
1008 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1009 if (!(link->flags & DL_FLAG_MANAGED))
1012 if (link->status != DL_STATE_AVAILABLE &&
1013 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1014 device_links_missing_supplier(dev);
1015 dev_err_probe(dev, -EPROBE_DEFER,
1016 "supplier %s not ready\n",
1017 dev_name(link->supplier));
1018 ret = -EPROBE_DEFER;
1021 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1023 dev->links.status = DL_DEV_PROBING;
1025 device_links_write_unlock();
1030 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1031 * @dev: Device to call sync_state() on
1032 * @list: List head to queue the @dev on
1034 * Queues a device for a sync_state() callback when the device links write lock
1035 * isn't held. This allows the sync_state() execution flow to use device links
1036 * APIs. The caller must ensure this function is called with
1037 * device_links_write_lock() held.
1039 * This function does a get_device() to make sure the device is not freed while
1042 * So the caller must also ensure that device_links_flush_sync_list() is called
1043 * as soon as the caller releases device_links_write_lock(). This is necessary
1044 * to make sure the sync_state() is called in a timely fashion and the
1045 * put_device() is called on this device.
1047 static void __device_links_queue_sync_state(struct device *dev,
1048 struct list_head *list)
1050 struct device_link *link;
1052 if (!dev_has_sync_state(dev))
1054 if (dev->state_synced)
1057 list_for_each_entry(link, &dev->links.consumers, s_node) {
1058 if (!(link->flags & DL_FLAG_MANAGED))
1060 if (link->status != DL_STATE_ACTIVE)
1065 * Set the flag here to avoid adding the same device to a list more
1066 * than once. This can happen if new consumers get added to the device
1067 * and probed before the list is flushed.
1069 dev->state_synced = true;
1071 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1075 list_add_tail(&dev->links.defer_sync, list);
1079 * device_links_flush_sync_list - Call sync_state() on a list of devices
1080 * @list: List of devices to call sync_state() on
1081 * @dont_lock_dev: Device for which lock is already held by the caller
1083 * Calls sync_state() on all the devices that have been queued for it. This
1084 * function is used in conjunction with __device_links_queue_sync_state(). The
1085 * @dont_lock_dev parameter is useful when this function is called from a
1086 * context where a device lock is already held.
1088 static void device_links_flush_sync_list(struct list_head *list,
1089 struct device *dont_lock_dev)
1091 struct device *dev, *tmp;
1093 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1094 list_del_init(&dev->links.defer_sync);
1096 if (dev != dont_lock_dev)
1099 if (dev->bus->sync_state)
1100 dev->bus->sync_state(dev);
1101 else if (dev->driver && dev->driver->sync_state)
1102 dev->driver->sync_state(dev);
1104 if (dev != dont_lock_dev)
1111 void device_links_supplier_sync_state_pause(void)
1113 device_links_write_lock();
1114 defer_sync_state_count++;
1115 device_links_write_unlock();
1118 void device_links_supplier_sync_state_resume(void)
1120 struct device *dev, *tmp;
1121 LIST_HEAD(sync_list);
1123 device_links_write_lock();
1124 if (!defer_sync_state_count) {
1125 WARN(true, "Unmatched sync_state pause/resume!");
1128 defer_sync_state_count--;
1129 if (defer_sync_state_count)
1132 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1134 * Delete from deferred_sync list before queuing it to
1135 * sync_list because defer_sync is used for both lists.
1137 list_del_init(&dev->links.defer_sync);
1138 __device_links_queue_sync_state(dev, &sync_list);
1141 device_links_write_unlock();
1143 device_links_flush_sync_list(&sync_list, NULL);
1146 static int sync_state_resume_initcall(void)
1148 device_links_supplier_sync_state_resume();
1151 late_initcall(sync_state_resume_initcall);
1153 static void __device_links_supplier_defer_sync(struct device *sup)
1155 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1156 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1159 static void device_link_drop_managed(struct device_link *link)
1161 link->flags &= ~DL_FLAG_MANAGED;
1162 WRITE_ONCE(link->status, DL_STATE_NONE);
1163 kref_put(&link->kref, __device_link_del);
1166 static ssize_t waiting_for_supplier_show(struct device *dev,
1167 struct device_attribute *attr,
1173 val = !list_empty(&dev->fwnode->suppliers);
1175 return sysfs_emit(buf, "%u\n", val);
1177 static DEVICE_ATTR_RO(waiting_for_supplier);
1180 * device_links_force_bind - Prepares device to be force bound
1181 * @dev: Consumer device.
1183 * device_bind_driver() force binds a device to a driver without calling any
1184 * driver probe functions. So the consumer really isn't going to wait for any
1185 * supplier before it's bound to the driver. We still want the device link
1186 * states to be sensible when this happens.
1188 * In preparation for device_bind_driver(), this function goes through each
1189 * supplier device links and checks if the supplier is bound. If it is, then
1190 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1191 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1193 void device_links_force_bind(struct device *dev)
1195 struct device_link *link, *ln;
1197 device_links_write_lock();
1199 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1200 if (!(link->flags & DL_FLAG_MANAGED))
1203 if (link->status != DL_STATE_AVAILABLE) {
1204 device_link_drop_managed(link);
1207 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1209 dev->links.status = DL_DEV_PROBING;
1211 device_links_write_unlock();
1215 * device_links_driver_bound - Update device links after probing its driver.
1216 * @dev: Device to update the links for.
1218 * The probe has been successful, so update links from this device to any
1219 * consumers by changing their status to "available".
1221 * Also change the status of @dev's links to suppliers to "active".
1223 * Links without the DL_FLAG_MANAGED flag set are ignored.
1225 void device_links_driver_bound(struct device *dev)
1227 struct device_link *link, *ln;
1228 LIST_HEAD(sync_list);
1231 * If a device binds successfully, it's expected to have created all
1232 * the device links it needs to or make new device links as it needs
1233 * them. So, fw_devlink no longer needs to create device links to any
1234 * of the device's suppliers.
1236 * Also, if a child firmware node of this bound device is not added as
1237 * a device by now, assume it is never going to be added and make sure
1238 * other devices don't defer probe indefinitely by waiting for such a
1241 if (dev->fwnode && dev->fwnode->dev == dev) {
1242 struct fwnode_handle *child;
1243 fwnode_links_purge_suppliers(dev->fwnode);
1244 fwnode_for_each_available_child_node(dev->fwnode, child)
1245 fw_devlink_purge_absent_suppliers(child);
1247 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1249 device_links_write_lock();
1251 list_for_each_entry(link, &dev->links.consumers, s_node) {
1252 if (!(link->flags & DL_FLAG_MANAGED))
1256 * Links created during consumer probe may be in the "consumer
1257 * probe" state to start with if the supplier is still probing
1258 * when they are created and they may become "active" if the
1259 * consumer probe returns first. Skip them here.
1261 if (link->status == DL_STATE_CONSUMER_PROBE ||
1262 link->status == DL_STATE_ACTIVE)
1265 WARN_ON(link->status != DL_STATE_DORMANT);
1266 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1268 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1269 driver_deferred_probe_add(link->consumer);
1272 if (defer_sync_state_count)
1273 __device_links_supplier_defer_sync(dev);
1275 __device_links_queue_sync_state(dev, &sync_list);
1277 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1278 struct device *supplier;
1280 if (!(link->flags & DL_FLAG_MANAGED))
1283 supplier = link->supplier;
1284 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1286 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1287 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1288 * save to drop the managed link completely.
1290 device_link_drop_managed(link);
1292 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1293 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1297 * This needs to be done even for the deleted
1298 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1299 * device link that was preventing the supplier from getting a
1300 * sync_state() call.
1302 if (defer_sync_state_count)
1303 __device_links_supplier_defer_sync(supplier);
1305 __device_links_queue_sync_state(supplier, &sync_list);
1308 dev->links.status = DL_DEV_DRIVER_BOUND;
1310 device_links_write_unlock();
1312 device_links_flush_sync_list(&sync_list, dev);
1316 * __device_links_no_driver - Update links of a device without a driver.
1317 * @dev: Device without a drvier.
1319 * Delete all non-persistent links from this device to any suppliers.
1321 * Persistent links stay around, but their status is changed to "available",
1322 * unless they already are in the "supplier unbind in progress" state in which
1323 * case they need not be updated.
1325 * Links without the DL_FLAG_MANAGED flag set are ignored.
1327 static void __device_links_no_driver(struct device *dev)
1329 struct device_link *link, *ln;
1331 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1332 if (!(link->flags & DL_FLAG_MANAGED))
1335 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1336 device_link_drop_managed(link);
1340 if (link->status != DL_STATE_CONSUMER_PROBE &&
1341 link->status != DL_STATE_ACTIVE)
1344 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1345 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1347 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1348 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1352 dev->links.status = DL_DEV_NO_DRIVER;
1356 * device_links_no_driver - Update links after failing driver probe.
1357 * @dev: Device whose driver has just failed to probe.
1359 * Clean up leftover links to consumers for @dev and invoke
1360 * %__device_links_no_driver() to update links to suppliers for it as
1363 * Links without the DL_FLAG_MANAGED flag set are ignored.
1365 void device_links_no_driver(struct device *dev)
1367 struct device_link *link;
1369 device_links_write_lock();
1371 list_for_each_entry(link, &dev->links.consumers, s_node) {
1372 if (!(link->flags & DL_FLAG_MANAGED))
1376 * The probe has failed, so if the status of the link is
1377 * "consumer probe" or "active", it must have been added by
1378 * a probing consumer while this device was still probing.
1379 * Change its state to "dormant", as it represents a valid
1380 * relationship, but it is not functionally meaningful.
1382 if (link->status == DL_STATE_CONSUMER_PROBE ||
1383 link->status == DL_STATE_ACTIVE)
1384 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1387 __device_links_no_driver(dev);
1389 device_links_write_unlock();
1393 * device_links_driver_cleanup - Update links after driver removal.
1394 * @dev: Device whose driver has just gone away.
1396 * Update links to consumers for @dev by changing their status to "dormant" and
1397 * invoke %__device_links_no_driver() to update links to suppliers for it as
1400 * Links without the DL_FLAG_MANAGED flag set are ignored.
1402 void device_links_driver_cleanup(struct device *dev)
1404 struct device_link *link, *ln;
1406 device_links_write_lock();
1408 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1409 if (!(link->flags & DL_FLAG_MANAGED))
1412 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1413 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1416 * autoremove the links between this @dev and its consumer
1417 * devices that are not active, i.e. where the link state
1418 * has moved to DL_STATE_SUPPLIER_UNBIND.
1420 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1421 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1422 device_link_drop_managed(link);
1424 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1427 list_del_init(&dev->links.defer_sync);
1428 __device_links_no_driver(dev);
1430 device_links_write_unlock();
1434 * device_links_busy - Check if there are any busy links to consumers.
1435 * @dev: Device to check.
1437 * Check each consumer of the device and return 'true' if its link's status
1438 * is one of "consumer probe" or "active" (meaning that the given consumer is
1439 * probing right now or its driver is present). Otherwise, change the link
1440 * state to "supplier unbind" to prevent the consumer from being probed
1441 * successfully going forward.
1443 * Return 'false' if there are no probing or active consumers.
1445 * Links without the DL_FLAG_MANAGED flag set are ignored.
1447 bool device_links_busy(struct device *dev)
1449 struct device_link *link;
1452 device_links_write_lock();
1454 list_for_each_entry(link, &dev->links.consumers, s_node) {
1455 if (!(link->flags & DL_FLAG_MANAGED))
1458 if (link->status == DL_STATE_CONSUMER_PROBE
1459 || link->status == DL_STATE_ACTIVE) {
1463 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1466 dev->links.status = DL_DEV_UNBINDING;
1468 device_links_write_unlock();
1473 * device_links_unbind_consumers - Force unbind consumers of the given device.
1474 * @dev: Device to unbind the consumers of.
1476 * Walk the list of links to consumers for @dev and if any of them is in the
1477 * "consumer probe" state, wait for all device probes in progress to complete
1480 * If that's not the case, change the status of the link to "supplier unbind"
1481 * and check if the link was in the "active" state. If so, force the consumer
1482 * driver to unbind and start over (the consumer will not re-probe as we have
1483 * changed the state of the link already).
1485 * Links without the DL_FLAG_MANAGED flag set are ignored.
1487 void device_links_unbind_consumers(struct device *dev)
1489 struct device_link *link;
1492 device_links_write_lock();
1494 list_for_each_entry(link, &dev->links.consumers, s_node) {
1495 enum device_link_state status;
1497 if (!(link->flags & DL_FLAG_MANAGED) ||
1498 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1501 status = link->status;
1502 if (status == DL_STATE_CONSUMER_PROBE) {
1503 device_links_write_unlock();
1505 wait_for_device_probe();
1508 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1509 if (status == DL_STATE_ACTIVE) {
1510 struct device *consumer = link->consumer;
1512 get_device(consumer);
1514 device_links_write_unlock();
1516 device_release_driver_internal(consumer, NULL,
1518 put_device(consumer);
1523 device_links_write_unlock();
1527 * device_links_purge - Delete existing links to other devices.
1528 * @dev: Target device.
1530 static void device_links_purge(struct device *dev)
1532 struct device_link *link, *ln;
1534 if (dev->class == &devlink_class)
1538 * Delete all of the remaining links from this device to any other
1539 * devices (either consumers or suppliers).
1541 device_links_write_lock();
1543 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1544 WARN_ON(link->status == DL_STATE_ACTIVE);
1545 __device_link_del(&link->kref);
1548 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1549 WARN_ON(link->status != DL_STATE_DORMANT &&
1550 link->status != DL_STATE_NONE);
1551 __device_link_del(&link->kref);
1554 device_links_write_unlock();
1557 #define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1558 DL_FLAG_SYNC_STATE_ONLY)
1559 #define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1560 DL_FLAG_AUTOPROBE_CONSUMER)
1561 #define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1564 static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1565 static int __init fw_devlink_setup(char *arg)
1570 if (strcmp(arg, "off") == 0) {
1571 fw_devlink_flags = 0;
1572 } else if (strcmp(arg, "permissive") == 0) {
1573 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1574 } else if (strcmp(arg, "on") == 0) {
1575 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1576 } else if (strcmp(arg, "rpm") == 0) {
1577 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1581 early_param("fw_devlink", fw_devlink_setup);
1583 static bool fw_devlink_strict;
1584 static int __init fw_devlink_strict_setup(char *arg)
1586 return strtobool(arg, &fw_devlink_strict);
1588 early_param("fw_devlink.strict", fw_devlink_strict_setup);
1590 u32 fw_devlink_get_flags(void)
1592 return fw_devlink_flags;
1595 static bool fw_devlink_is_permissive(void)
1597 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1600 bool fw_devlink_is_strict(void)
1602 return fw_devlink_strict && !fw_devlink_is_permissive();
1605 static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1607 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1610 fwnode_call_int_op(fwnode, add_links);
1611 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1614 static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1616 struct fwnode_handle *child = NULL;
1618 fw_devlink_parse_fwnode(fwnode);
1620 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1621 fw_devlink_parse_fwtree(child);
1624 static void fw_devlink_relax_link(struct device_link *link)
1626 if (!(link->flags & DL_FLAG_INFERRED))
1629 if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE))
1632 pm_runtime_drop_link(link);
1633 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1634 dev_dbg(link->consumer, "Relaxing link with %s\n",
1635 dev_name(link->supplier));
1638 static int fw_devlink_no_driver(struct device *dev, void *data)
1640 struct device_link *link = to_devlink(dev);
1642 if (!link->supplier->can_match)
1643 fw_devlink_relax_link(link);
1648 void fw_devlink_drivers_done(void)
1650 fw_devlink_drv_reg_done = true;
1651 device_links_write_lock();
1652 class_for_each_device(&devlink_class, NULL, NULL,
1653 fw_devlink_no_driver);
1654 device_links_write_unlock();
1657 static void fw_devlink_unblock_consumers(struct device *dev)
1659 struct device_link *link;
1661 if (!fw_devlink_flags || fw_devlink_is_permissive())
1664 device_links_write_lock();
1665 list_for_each_entry(link, &dev->links.consumers, s_node)
1666 fw_devlink_relax_link(link);
1667 device_links_write_unlock();
1671 * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links
1672 * @con: Device to check dependencies for.
1673 * @sup: Device to check against.
1675 * Check if @sup depends on @con or any device dependent on it (its child or
1676 * its consumer etc). When such a cyclic dependency is found, convert all
1677 * device links created solely by fw_devlink into SYNC_STATE_ONLY device links.
1678 * This is the equivalent of doing fw_devlink=permissive just between the
1679 * devices in the cycle. We need to do this because, at this point, fw_devlink
1680 * can't tell which of these dependencies is not a real dependency.
1682 * Return 1 if a cycle is found. Otherwise, return 0.
1684 static int fw_devlink_relax_cycle(struct device *con, void *sup)
1686 struct device_link *link;
1692 ret = device_for_each_child(con, sup, fw_devlink_relax_cycle);
1696 list_for_each_entry(link, &con->links.consumers, s_node) {
1697 if ((link->flags & ~DL_FLAG_INFERRED) ==
1698 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
1701 if (!fw_devlink_relax_cycle(link->consumer, sup))
1706 fw_devlink_relax_link(link);
1712 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
1713 * @con: consumer device for the device link
1714 * @sup_handle: fwnode handle of supplier
1715 * @flags: devlink flags
1717 * This function will try to create a device link between the consumer device
1718 * @con and the supplier device represented by @sup_handle.
1720 * The supplier has to be provided as a fwnode because incorrect cycles in
1721 * fwnode links can sometimes cause the supplier device to never be created.
1722 * This function detects such cases and returns an error if it cannot create a
1723 * device link from the consumer to a missing supplier.
1726 * 0 on successfully creating a device link
1727 * -EINVAL if the device link cannot be created as expected
1728 * -EAGAIN if the device link cannot be created right now, but it may be
1729 * possible to do that in the future
1731 static int fw_devlink_create_devlink(struct device *con,
1732 struct fwnode_handle *sup_handle, u32 flags)
1734 struct device *sup_dev;
1738 * In some cases, a device P might also be a supplier to its child node
1739 * C. However, this would defer the probe of C until the probe of P
1740 * completes successfully. This is perfectly fine in the device driver
1741 * model. device_add() doesn't guarantee probe completion of the device
1742 * by the time it returns.
1744 * However, there are a few drivers that assume C will finish probing
1745 * as soon as it's added and before P finishes probing. So, we provide
1746 * a flag to let fw_devlink know not to delay the probe of C until the
1747 * probe of P completes successfully.
1749 * When such a flag is set, we can't create device links where P is the
1750 * supplier of C as that would delay the probe of C.
1752 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
1753 fwnode_is_ancestor_of(sup_handle, con->fwnode))
1756 sup_dev = get_dev_from_fwnode(sup_handle);
1759 * If it's one of those drivers that don't actually bind to
1760 * their device using driver core, then don't wait on this
1761 * supplier device indefinitely.
1763 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
1764 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
1770 * If this fails, it is due to cycles in device links. Just
1771 * give up on this link and treat it as invalid.
1773 if (!device_link_add(con, sup_dev, flags) &&
1774 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
1775 dev_info(con, "Fixing up cyclic dependency with %s\n",
1777 device_links_write_lock();
1778 fw_devlink_relax_cycle(con, sup_dev);
1779 device_links_write_unlock();
1780 device_link_add(con, sup_dev,
1781 FW_DEVLINK_FLAGS_PERMISSIVE);
1788 /* Supplier that's already initialized without a struct device. */
1789 if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
1793 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
1794 * cycles. So cycle detection isn't necessary and shouldn't be
1797 if (flags & DL_FLAG_SYNC_STATE_ONLY)
1801 * If we can't find the supplier device from its fwnode, it might be
1802 * due to a cyclic dependency between fwnodes. Some of these cycles can
1803 * be broken by applying logic. Check for these types of cycles and
1804 * break them so that devices in the cycle probe properly.
1806 * If the supplier's parent is dependent on the consumer, then the
1807 * consumer and supplier have a cyclic dependency. Since fw_devlink
1808 * can't tell which of the inferred dependencies are incorrect, don't
1809 * enforce probe ordering between any of the devices in this cyclic
1810 * dependency. Do this by relaxing all the fw_devlink device links in
1811 * this cycle and by treating the fwnode link between the consumer and
1812 * the supplier as an invalid dependency.
1814 sup_dev = fwnode_get_next_parent_dev(sup_handle);
1815 if (sup_dev && device_is_dependent(con, sup_dev)) {
1816 dev_info(con, "Fixing up cyclic dependency with %pfwP (%s)\n",
1817 sup_handle, dev_name(sup_dev));
1818 device_links_write_lock();
1819 fw_devlink_relax_cycle(con, sup_dev);
1820 device_links_write_unlock();
1824 * Can't check for cycles or no cycles. So let's try
1831 put_device(sup_dev);
1836 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
1837 * @dev: Device that needs to be linked to its consumers
1839 * This function looks at all the consumer fwnodes of @dev and creates device
1840 * links between the consumer device and @dev (supplier).
1842 * If the consumer device has not been added yet, then this function creates a
1843 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
1844 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
1845 * sync_state() callback before the real consumer device gets to be added and
1848 * Once device links are created from the real consumer to @dev (supplier), the
1849 * fwnode links are deleted.
1851 static void __fw_devlink_link_to_consumers(struct device *dev)
1853 struct fwnode_handle *fwnode = dev->fwnode;
1854 struct fwnode_link *link, *tmp;
1856 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
1857 u32 dl_flags = fw_devlink_get_flags();
1858 struct device *con_dev;
1859 bool own_link = true;
1862 con_dev = get_dev_from_fwnode(link->consumer);
1864 * If consumer device is not available yet, make a "proxy"
1865 * SYNC_STATE_ONLY link from the consumer's parent device to
1866 * the supplier device. This is necessary to make sure the
1867 * supplier doesn't get a sync_state() callback before the real
1868 * consumer can create a device link to the supplier.
1870 * This proxy link step is needed to handle the case where the
1871 * consumer's parent device is added before the supplier.
1874 con_dev = fwnode_get_next_parent_dev(link->consumer);
1876 * However, if the consumer's parent device is also the
1877 * parent of the supplier, don't create a
1878 * consumer-supplier link from the parent to its child
1879 * device. Such a dependency is impossible.
1882 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
1883 put_device(con_dev);
1887 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1894 ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags);
1895 put_device(con_dev);
1896 if (!own_link || ret == -EAGAIN)
1899 __fwnode_link_del(link);
1904 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
1905 * @dev: The consumer device that needs to be linked to its suppliers
1906 * @fwnode: Root of the fwnode tree that is used to create device links
1908 * This function looks at all the supplier fwnodes of fwnode tree rooted at
1909 * @fwnode and creates device links between @dev (consumer) and all the
1910 * supplier devices of the entire fwnode tree at @fwnode.
1912 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
1913 * and the real suppliers of @dev. Once these device links are created, the
1914 * fwnode links are deleted. When such device links are successfully created,
1915 * this function is called recursively on those supplier devices. This is
1916 * needed to detect and break some invalid cycles in fwnode links. See
1917 * fw_devlink_create_devlink() for more details.
1919 * In addition, it also looks at all the suppliers of the entire fwnode tree
1920 * because some of the child devices of @dev that have not been added yet
1921 * (because @dev hasn't probed) might already have their suppliers added to
1922 * driver core. So, this function creates SYNC_STATE_ONLY device links between
1923 * @dev (consumer) and these suppliers to make sure they don't execute their
1924 * sync_state() callbacks before these child devices have a chance to create
1925 * their device links. The fwnode links that correspond to the child devices
1926 * aren't delete because they are needed later to create the device links
1927 * between the real consumer and supplier devices.
1929 static void __fw_devlink_link_to_suppliers(struct device *dev,
1930 struct fwnode_handle *fwnode)
1932 bool own_link = (dev->fwnode == fwnode);
1933 struct fwnode_link *link, *tmp;
1934 struct fwnode_handle *child = NULL;
1938 dl_flags = fw_devlink_get_flags();
1940 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1942 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
1944 struct device *sup_dev;
1945 struct fwnode_handle *sup = link->supplier;
1947 ret = fw_devlink_create_devlink(dev, sup, dl_flags);
1948 if (!own_link || ret == -EAGAIN)
1951 __fwnode_link_del(link);
1953 /* If no device link was created, nothing more to do. */
1958 * If a device link was successfully created to a supplier, we
1959 * now need to try and link the supplier to all its suppliers.
1961 * This is needed to detect and delete false dependencies in
1962 * fwnode links that haven't been converted to a device link
1963 * yet. See comments in fw_devlink_create_devlink() for more
1964 * details on the false dependency.
1966 * Without deleting these false dependencies, some devices will
1967 * never probe because they'll keep waiting for their false
1968 * dependency fwnode links to be converted to device links.
1970 sup_dev = get_dev_from_fwnode(sup);
1971 __fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode);
1972 put_device(sup_dev);
1976 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
1977 * all the descendants. This proxy link step is needed to handle the
1978 * case where the supplier is added before the consumer's parent device
1981 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1982 __fw_devlink_link_to_suppliers(dev, child);
1985 static void fw_devlink_link_device(struct device *dev)
1987 struct fwnode_handle *fwnode = dev->fwnode;
1989 if (!fw_devlink_flags)
1992 fw_devlink_parse_fwtree(fwnode);
1994 mutex_lock(&fwnode_link_lock);
1995 __fw_devlink_link_to_consumers(dev);
1996 __fw_devlink_link_to_suppliers(dev, fwnode);
1997 mutex_unlock(&fwnode_link_lock);
2000 /* Device links support end. */
2002 int (*platform_notify)(struct device *dev) = NULL;
2003 int (*platform_notify_remove)(struct device *dev) = NULL;
2004 static struct kobject *dev_kobj;
2005 struct kobject *sysfs_dev_char_kobj;
2006 struct kobject *sysfs_dev_block_kobj;
2008 static DEFINE_MUTEX(device_hotplug_lock);
2010 void lock_device_hotplug(void)
2012 mutex_lock(&device_hotplug_lock);
2015 void unlock_device_hotplug(void)
2017 mutex_unlock(&device_hotplug_lock);
2020 int lock_device_hotplug_sysfs(void)
2022 if (mutex_trylock(&device_hotplug_lock))
2025 /* Avoid busy looping (5 ms of sleep should do). */
2027 return restart_syscall();
2031 static inline int device_is_not_partition(struct device *dev)
2033 return !(dev->type == &part_type);
2036 static inline int device_is_not_partition(struct device *dev)
2042 static void device_platform_notify(struct device *dev)
2044 acpi_device_notify(dev);
2046 software_node_notify(dev);
2048 if (platform_notify)
2049 platform_notify(dev);
2052 static void device_platform_notify_remove(struct device *dev)
2054 acpi_device_notify_remove(dev);
2056 software_node_notify_remove(dev);
2058 if (platform_notify_remove)
2059 platform_notify_remove(dev);
2063 * dev_driver_string - Return a device's driver name, if at all possible
2064 * @dev: struct device to get the name of
2066 * Will return the device's driver's name if it is bound to a device. If
2067 * the device is not bound to a driver, it will return the name of the bus
2068 * it is attached to. If it is not attached to a bus either, an empty
2069 * string will be returned.
2071 const char *dev_driver_string(const struct device *dev)
2073 struct device_driver *drv;
2075 /* dev->driver can change to NULL underneath us because of unbinding,
2076 * so be careful about accessing it. dev->bus and dev->class should
2077 * never change once they are set, so they don't need special care.
2079 drv = READ_ONCE(dev->driver);
2080 return drv ? drv->name : dev_bus_name(dev);
2082 EXPORT_SYMBOL(dev_driver_string);
2084 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2086 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2089 struct device_attribute *dev_attr = to_dev_attr(attr);
2090 struct device *dev = kobj_to_dev(kobj);
2094 ret = dev_attr->show(dev, dev_attr, buf);
2095 if (ret >= (ssize_t)PAGE_SIZE) {
2096 printk("dev_attr_show: %pS returned bad count\n",
2102 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2103 const char *buf, size_t count)
2105 struct device_attribute *dev_attr = to_dev_attr(attr);
2106 struct device *dev = kobj_to_dev(kobj);
2109 if (dev_attr->store)
2110 ret = dev_attr->store(dev, dev_attr, buf, count);
2114 static const struct sysfs_ops dev_sysfs_ops = {
2115 .show = dev_attr_show,
2116 .store = dev_attr_store,
2119 #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2121 ssize_t device_store_ulong(struct device *dev,
2122 struct device_attribute *attr,
2123 const char *buf, size_t size)
2125 struct dev_ext_attribute *ea = to_ext_attr(attr);
2129 ret = kstrtoul(buf, 0, &new);
2132 *(unsigned long *)(ea->var) = new;
2133 /* Always return full write size even if we didn't consume all */
2136 EXPORT_SYMBOL_GPL(device_store_ulong);
2138 ssize_t device_show_ulong(struct device *dev,
2139 struct device_attribute *attr,
2142 struct dev_ext_attribute *ea = to_ext_attr(attr);
2143 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2145 EXPORT_SYMBOL_GPL(device_show_ulong);
2147 ssize_t device_store_int(struct device *dev,
2148 struct device_attribute *attr,
2149 const char *buf, size_t size)
2151 struct dev_ext_attribute *ea = to_ext_attr(attr);
2155 ret = kstrtol(buf, 0, &new);
2159 if (new > INT_MAX || new < INT_MIN)
2161 *(int *)(ea->var) = new;
2162 /* Always return full write size even if we didn't consume all */
2165 EXPORT_SYMBOL_GPL(device_store_int);
2167 ssize_t device_show_int(struct device *dev,
2168 struct device_attribute *attr,
2171 struct dev_ext_attribute *ea = to_ext_attr(attr);
2173 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2175 EXPORT_SYMBOL_GPL(device_show_int);
2177 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2178 const char *buf, size_t size)
2180 struct dev_ext_attribute *ea = to_ext_attr(attr);
2182 if (strtobool(buf, ea->var) < 0)
2187 EXPORT_SYMBOL_GPL(device_store_bool);
2189 ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2192 struct dev_ext_attribute *ea = to_ext_attr(attr);
2194 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2196 EXPORT_SYMBOL_GPL(device_show_bool);
2199 * device_release - free device structure.
2200 * @kobj: device's kobject.
2202 * This is called once the reference count for the object
2203 * reaches 0. We forward the call to the device's release
2204 * method, which should handle actually freeing the structure.
2206 static void device_release(struct kobject *kobj)
2208 struct device *dev = kobj_to_dev(kobj);
2209 struct device_private *p = dev->p;
2212 * Some platform devices are driven without driver attached
2213 * and managed resources may have been acquired. Make sure
2214 * all resources are released.
2216 * Drivers still can add resources into device after device
2217 * is deleted but alive, so release devres here to avoid
2218 * possible memory leak.
2220 devres_release_all(dev);
2222 kfree(dev->dma_range_map);
2226 else if (dev->type && dev->type->release)
2227 dev->type->release(dev);
2228 else if (dev->class && dev->class->dev_release)
2229 dev->class->dev_release(dev);
2231 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",
2236 static const void *device_namespace(struct kobject *kobj)
2238 struct device *dev = kobj_to_dev(kobj);
2239 const void *ns = NULL;
2241 if (dev->class && dev->class->ns_type)
2242 ns = dev->class->namespace(dev);
2247 static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2249 struct device *dev = kobj_to_dev(kobj);
2251 if (dev->class && dev->class->get_ownership)
2252 dev->class->get_ownership(dev, uid, gid);
2255 static struct kobj_type device_ktype = {
2256 .release = device_release,
2257 .sysfs_ops = &dev_sysfs_ops,
2258 .namespace = device_namespace,
2259 .get_ownership = device_get_ownership,
2263 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
2265 struct kobj_type *ktype = get_ktype(kobj);
2267 if (ktype == &device_ktype) {
2268 struct device *dev = kobj_to_dev(kobj);
2277 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
2279 struct device *dev = kobj_to_dev(kobj);
2282 return dev->bus->name;
2284 return dev->class->name;
2288 static int dev_uevent(struct kset *kset, struct kobject *kobj,
2289 struct kobj_uevent_env *env)
2291 struct device *dev = kobj_to_dev(kobj);
2294 /* add device node properties if present */
2295 if (MAJOR(dev->devt)) {
2299 kuid_t uid = GLOBAL_ROOT_UID;
2300 kgid_t gid = GLOBAL_ROOT_GID;
2302 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2303 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2304 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2306 add_uevent_var(env, "DEVNAME=%s", name);
2308 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2309 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2310 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2311 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2312 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2317 if (dev->type && dev->type->name)
2318 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2321 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2323 /* Add common DT information about the device */
2324 of_device_uevent(dev, env);
2326 /* have the bus specific function add its stuff */
2327 if (dev->bus && dev->bus->uevent) {
2328 retval = dev->bus->uevent(dev, env);
2330 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2331 dev_name(dev), __func__, retval);
2334 /* have the class specific function add its stuff */
2335 if (dev->class && dev->class->dev_uevent) {
2336 retval = dev->class->dev_uevent(dev, env);
2338 pr_debug("device: '%s': %s: class uevent() "
2339 "returned %d\n", dev_name(dev),
2343 /* have the device type specific function add its stuff */
2344 if (dev->type && dev->type->uevent) {
2345 retval = dev->type->uevent(dev, env);
2347 pr_debug("device: '%s': %s: dev_type uevent() "
2348 "returned %d\n", dev_name(dev),
2355 static const struct kset_uevent_ops device_uevent_ops = {
2356 .filter = dev_uevent_filter,
2357 .name = dev_uevent_name,
2358 .uevent = dev_uevent,
2361 static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2364 struct kobject *top_kobj;
2366 struct kobj_uevent_env *env = NULL;
2371 /* search the kset, the device belongs to */
2372 top_kobj = &dev->kobj;
2373 while (!top_kobj->kset && top_kobj->parent)
2374 top_kobj = top_kobj->parent;
2375 if (!top_kobj->kset)
2378 kset = top_kobj->kset;
2379 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2382 /* respect filter */
2383 if (kset->uevent_ops && kset->uevent_ops->filter)
2384 if (!kset->uevent_ops->filter(kset, &dev->kobj))
2387 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2391 /* let the kset specific function add its keys */
2392 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
2396 /* copy keys to file */
2397 for (i = 0; i < env->envp_idx; i++)
2398 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2404 static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2405 const char *buf, size_t count)
2409 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2412 dev_err(dev, "uevent: failed to send synthetic uevent\n");
2418 static DEVICE_ATTR_RW(uevent);
2420 static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2426 val = !dev->offline;
2428 return sysfs_emit(buf, "%u\n", val);
2431 static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2432 const char *buf, size_t count)
2437 ret = strtobool(buf, &val);
2441 ret = lock_device_hotplug_sysfs();
2445 ret = val ? device_online(dev) : device_offline(dev);
2446 unlock_device_hotplug();
2447 return ret < 0 ? ret : count;
2449 static DEVICE_ATTR_RW(online);
2451 static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2456 switch (dev->removable) {
2457 case DEVICE_REMOVABLE:
2466 return sysfs_emit(buf, "%s\n", loc);
2468 static DEVICE_ATTR_RO(removable);
2470 int device_add_groups(struct device *dev, const struct attribute_group **groups)
2472 return sysfs_create_groups(&dev->kobj, groups);
2474 EXPORT_SYMBOL_GPL(device_add_groups);
2476 void device_remove_groups(struct device *dev,
2477 const struct attribute_group **groups)
2479 sysfs_remove_groups(&dev->kobj, groups);
2481 EXPORT_SYMBOL_GPL(device_remove_groups);
2483 union device_attr_group_devres {
2484 const struct attribute_group *group;
2485 const struct attribute_group **groups;
2488 static int devm_attr_group_match(struct device *dev, void *res, void *data)
2490 return ((union device_attr_group_devres *)res)->group == data;
2493 static void devm_attr_group_remove(struct device *dev, void *res)
2495 union device_attr_group_devres *devres = res;
2496 const struct attribute_group *group = devres->group;
2498 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2499 sysfs_remove_group(&dev->kobj, group);
2502 static void devm_attr_groups_remove(struct device *dev, void *res)
2504 union device_attr_group_devres *devres = res;
2505 const struct attribute_group **groups = devres->groups;
2507 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2508 sysfs_remove_groups(&dev->kobj, groups);
2512 * devm_device_add_group - given a device, create a managed attribute group
2513 * @dev: The device to create the group for
2514 * @grp: The attribute group to create
2516 * This function creates a group for the first time. It will explicitly
2517 * warn and error if any of the attribute files being created already exist.
2519 * Returns 0 on success or error code on failure.
2521 int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2523 union device_attr_group_devres *devres;
2526 devres = devres_alloc(devm_attr_group_remove,
2527 sizeof(*devres), GFP_KERNEL);
2531 error = sysfs_create_group(&dev->kobj, grp);
2533 devres_free(devres);
2537 devres->group = grp;
2538 devres_add(dev, devres);
2541 EXPORT_SYMBOL_GPL(devm_device_add_group);
2544 * devm_device_remove_group: remove a managed group from a device
2545 * @dev: device to remove the group from
2546 * @grp: group to remove
2548 * This function removes a group of attributes from a device. The attributes
2549 * previously have to have been created for this group, otherwise it will fail.
2551 void devm_device_remove_group(struct device *dev,
2552 const struct attribute_group *grp)
2554 WARN_ON(devres_release(dev, devm_attr_group_remove,
2555 devm_attr_group_match,
2556 /* cast away const */ (void *)grp));
2558 EXPORT_SYMBOL_GPL(devm_device_remove_group);
2561 * devm_device_add_groups - create a bunch of managed attribute groups
2562 * @dev: The device to create the group for
2563 * @groups: The attribute groups to create, NULL terminated
2565 * This function creates a bunch of managed attribute groups. If an error
2566 * occurs when creating a group, all previously created groups will be
2567 * removed, unwinding everything back to the original state when this
2568 * function was called. It will explicitly warn and error if any of the
2569 * attribute files being created already exist.
2571 * Returns 0 on success or error code from sysfs_create_group on failure.
2573 int devm_device_add_groups(struct device *dev,
2574 const struct attribute_group **groups)
2576 union device_attr_group_devres *devres;
2579 devres = devres_alloc(devm_attr_groups_remove,
2580 sizeof(*devres), GFP_KERNEL);
2584 error = sysfs_create_groups(&dev->kobj, groups);
2586 devres_free(devres);
2590 devres->groups = groups;
2591 devres_add(dev, devres);
2594 EXPORT_SYMBOL_GPL(devm_device_add_groups);
2597 * devm_device_remove_groups - remove a list of managed groups
2599 * @dev: The device for the groups to be removed from
2600 * @groups: NULL terminated list of groups to be removed
2602 * If groups is not NULL, remove the specified groups from the device.
2604 void devm_device_remove_groups(struct device *dev,
2605 const struct attribute_group **groups)
2607 WARN_ON(devres_release(dev, devm_attr_groups_remove,
2608 devm_attr_group_match,
2609 /* cast away const */ (void *)groups));
2611 EXPORT_SYMBOL_GPL(devm_device_remove_groups);
2613 static int device_add_attrs(struct device *dev)
2615 struct class *class = dev->class;
2616 const struct device_type *type = dev->type;
2620 error = device_add_groups(dev, class->dev_groups);
2626 error = device_add_groups(dev, type->groups);
2628 goto err_remove_class_groups;
2631 error = device_add_groups(dev, dev->groups);
2633 goto err_remove_type_groups;
2635 if (device_supports_offline(dev) && !dev->offline_disabled) {
2636 error = device_create_file(dev, &dev_attr_online);
2638 goto err_remove_dev_groups;
2641 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2642 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2644 goto err_remove_dev_online;
2647 if (dev_removable_is_valid(dev)) {
2648 error = device_create_file(dev, &dev_attr_removable);
2650 goto err_remove_dev_waiting_for_supplier;
2655 err_remove_dev_waiting_for_supplier:
2656 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2657 err_remove_dev_online:
2658 device_remove_file(dev, &dev_attr_online);
2659 err_remove_dev_groups:
2660 device_remove_groups(dev, dev->groups);
2661 err_remove_type_groups:
2663 device_remove_groups(dev, type->groups);
2664 err_remove_class_groups:
2666 device_remove_groups(dev, class->dev_groups);
2671 static void device_remove_attrs(struct device *dev)
2673 struct class *class = dev->class;
2674 const struct device_type *type = dev->type;
2676 device_remove_file(dev, &dev_attr_removable);
2677 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2678 device_remove_file(dev, &dev_attr_online);
2679 device_remove_groups(dev, dev->groups);
2682 device_remove_groups(dev, type->groups);
2685 device_remove_groups(dev, class->dev_groups);
2688 static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2691 return print_dev_t(buf, dev->devt);
2693 static DEVICE_ATTR_RO(dev);
2696 struct kset *devices_kset;
2699 * devices_kset_move_before - Move device in the devices_kset's list.
2700 * @deva: Device to move.
2701 * @devb: Device @deva should come before.
2703 static void devices_kset_move_before(struct device *deva, struct device *devb)
2707 pr_debug("devices_kset: Moving %s before %s\n",
2708 dev_name(deva), dev_name(devb));
2709 spin_lock(&devices_kset->list_lock);
2710 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2711 spin_unlock(&devices_kset->list_lock);
2715 * devices_kset_move_after - Move device in the devices_kset's list.
2716 * @deva: Device to move
2717 * @devb: Device @deva should come after.
2719 static void devices_kset_move_after(struct device *deva, struct device *devb)
2723 pr_debug("devices_kset: Moving %s after %s\n",
2724 dev_name(deva), dev_name(devb));
2725 spin_lock(&devices_kset->list_lock);
2726 list_move(&deva->kobj.entry, &devb->kobj.entry);
2727 spin_unlock(&devices_kset->list_lock);
2731 * devices_kset_move_last - move the device to the end of devices_kset's list.
2732 * @dev: device to move
2734 void devices_kset_move_last(struct device *dev)
2738 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2739 spin_lock(&devices_kset->list_lock);
2740 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2741 spin_unlock(&devices_kset->list_lock);
2745 * device_create_file - create sysfs attribute file for device.
2747 * @attr: device attribute descriptor.
2749 int device_create_file(struct device *dev,
2750 const struct device_attribute *attr)
2755 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
2756 "Attribute %s: write permission without 'store'\n",
2758 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
2759 "Attribute %s: read permission without 'show'\n",
2761 error = sysfs_create_file(&dev->kobj, &attr->attr);
2766 EXPORT_SYMBOL_GPL(device_create_file);
2769 * device_remove_file - remove sysfs attribute file.
2771 * @attr: device attribute descriptor.
2773 void device_remove_file(struct device *dev,
2774 const struct device_attribute *attr)
2777 sysfs_remove_file(&dev->kobj, &attr->attr);
2779 EXPORT_SYMBOL_GPL(device_remove_file);
2782 * device_remove_file_self - remove sysfs attribute file from its own method.
2784 * @attr: device attribute descriptor.
2786 * See kernfs_remove_self() for details.
2788 bool device_remove_file_self(struct device *dev,
2789 const struct device_attribute *attr)
2792 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
2796 EXPORT_SYMBOL_GPL(device_remove_file_self);
2799 * device_create_bin_file - create sysfs binary attribute file for device.
2801 * @attr: device binary attribute descriptor.
2803 int device_create_bin_file(struct device *dev,
2804 const struct bin_attribute *attr)
2806 int error = -EINVAL;
2808 error = sysfs_create_bin_file(&dev->kobj, attr);
2811 EXPORT_SYMBOL_GPL(device_create_bin_file);
2814 * device_remove_bin_file - remove sysfs binary attribute file
2816 * @attr: device binary attribute descriptor.
2818 void device_remove_bin_file(struct device *dev,
2819 const struct bin_attribute *attr)
2822 sysfs_remove_bin_file(&dev->kobj, attr);
2824 EXPORT_SYMBOL_GPL(device_remove_bin_file);
2826 static void klist_children_get(struct klist_node *n)
2828 struct device_private *p = to_device_private_parent(n);
2829 struct device *dev = p->device;
2834 static void klist_children_put(struct klist_node *n)
2836 struct device_private *p = to_device_private_parent(n);
2837 struct device *dev = p->device;
2843 * device_initialize - init device structure.
2846 * This prepares the device for use by other layers by initializing
2848 * It is the first half of device_register(), if called by
2849 * that function, though it can also be called separately, so one
2850 * may use @dev's fields. In particular, get_device()/put_device()
2851 * may be used for reference counting of @dev after calling this
2854 * All fields in @dev must be initialized by the caller to 0, except
2855 * for those explicitly set to some other value. The simplest
2856 * approach is to use kzalloc() to allocate the structure containing
2859 * NOTE: Use put_device() to give up your reference instead of freeing
2860 * @dev directly once you have called this function.
2862 void device_initialize(struct device *dev)
2864 dev->kobj.kset = devices_kset;
2865 kobject_init(&dev->kobj, &device_ktype);
2866 INIT_LIST_HEAD(&dev->dma_pools);
2867 mutex_init(&dev->mutex);
2868 #ifdef CONFIG_PROVE_LOCKING
2869 mutex_init(&dev->lockdep_mutex);
2871 lockdep_set_novalidate_class(&dev->mutex);
2872 spin_lock_init(&dev->devres_lock);
2873 INIT_LIST_HEAD(&dev->devres_head);
2874 device_pm_init(dev);
2875 set_dev_node(dev, NUMA_NO_NODE);
2876 #ifdef CONFIG_GENERIC_MSI_IRQ
2877 raw_spin_lock_init(&dev->msi_lock);
2878 INIT_LIST_HEAD(&dev->msi_list);
2880 INIT_LIST_HEAD(&dev->links.consumers);
2881 INIT_LIST_HEAD(&dev->links.suppliers);
2882 INIT_LIST_HEAD(&dev->links.defer_sync);
2883 dev->links.status = DL_DEV_NO_DRIVER;
2884 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
2885 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
2886 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
2887 dev->dma_coherent = dma_default_coherent;
2889 #ifdef CONFIG_SWIOTLB
2890 dev->dma_io_tlb_mem = &io_tlb_default_mem;
2893 EXPORT_SYMBOL_GPL(device_initialize);
2895 struct kobject *virtual_device_parent(struct device *dev)
2897 static struct kobject *virtual_dir = NULL;
2900 virtual_dir = kobject_create_and_add("virtual",
2901 &devices_kset->kobj);
2907 struct kobject kobj;
2908 struct class *class;
2911 #define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
2913 static void class_dir_release(struct kobject *kobj)
2915 struct class_dir *dir = to_class_dir(kobj);
2920 struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
2922 struct class_dir *dir = to_class_dir(kobj);
2923 return dir->class->ns_type;
2926 static struct kobj_type class_dir_ktype = {
2927 .release = class_dir_release,
2928 .sysfs_ops = &kobj_sysfs_ops,
2929 .child_ns_type = class_dir_child_ns_type
2932 static struct kobject *
2933 class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
2935 struct class_dir *dir;
2938 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
2940 return ERR_PTR(-ENOMEM);
2943 kobject_init(&dir->kobj, &class_dir_ktype);
2945 dir->kobj.kset = &class->p->glue_dirs;
2947 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
2949 kobject_put(&dir->kobj);
2950 return ERR_PTR(retval);
2955 static DEFINE_MUTEX(gdp_mutex);
2957 static struct kobject *get_device_parent(struct device *dev,
2958 struct device *parent)
2961 struct kobject *kobj = NULL;
2962 struct kobject *parent_kobj;
2966 /* block disks show up in /sys/block */
2967 if (sysfs_deprecated && dev->class == &block_class) {
2968 if (parent && parent->class == &block_class)
2969 return &parent->kobj;
2970 return &block_class.p->subsys.kobj;
2975 * If we have no parent, we live in "virtual".
2976 * Class-devices with a non class-device as parent, live
2977 * in a "glue" directory to prevent namespace collisions.
2980 parent_kobj = virtual_device_parent(dev);
2981 else if (parent->class && !dev->class->ns_type)
2982 return &parent->kobj;
2984 parent_kobj = &parent->kobj;
2986 mutex_lock(&gdp_mutex);
2988 /* find our class-directory at the parent and reference it */
2989 spin_lock(&dev->class->p->glue_dirs.list_lock);
2990 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
2991 if (k->parent == parent_kobj) {
2992 kobj = kobject_get(k);
2995 spin_unlock(&dev->class->p->glue_dirs.list_lock);
2997 mutex_unlock(&gdp_mutex);
3001 /* or create a new class-directory at the parent device */
3002 k = class_dir_create_and_add(dev->class, parent_kobj);
3003 /* do not emit an uevent for this simple "glue" directory */
3004 mutex_unlock(&gdp_mutex);
3008 /* subsystems can specify a default root directory for their devices */
3009 if (!parent && dev->bus && dev->bus->dev_root)
3010 return &dev->bus->dev_root->kobj;
3013 return &parent->kobj;
3017 static inline bool live_in_glue_dir(struct kobject *kobj,
3020 if (!kobj || !dev->class ||
3021 kobj->kset != &dev->class->p->glue_dirs)
3026 static inline struct kobject *get_glue_dir(struct device *dev)
3028 return dev->kobj.parent;
3032 * make sure cleaning up dir as the last step, we need to make
3033 * sure .release handler of kobject is run with holding the
3036 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3040 /* see if we live in a "glue" directory */
3041 if (!live_in_glue_dir(glue_dir, dev))
3044 mutex_lock(&gdp_mutex);
3046 * There is a race condition between removing glue directory
3047 * and adding a new device under the glue directory.
3052 * get_device_parent()
3053 * class_dir_create_and_add()
3054 * kobject_add_internal()
3055 * create_dir() // create glue_dir
3058 * get_device_parent()
3059 * kobject_get() // get glue_dir
3062 * cleanup_glue_dir()
3063 * kobject_del(glue_dir)
3066 * kobject_add_internal()
3067 * create_dir() // in glue_dir
3068 * sysfs_create_dir_ns()
3069 * kernfs_create_dir_ns(sd)
3071 * sysfs_remove_dir() // glue_dir->sd=NULL
3072 * sysfs_put() // free glue_dir->sd
3075 * kernfs_new_node(sd)
3076 * kernfs_get(glue_dir)
3080 * Before CPU1 remove last child device under glue dir, if CPU2 add
3081 * a new device under glue dir, the glue_dir kobject reference count
3082 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3083 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3084 * and sysfs_put(). This result in glue_dir->sd is freed.
3086 * Then the CPU2 will see a stale "empty" but still potentially used
3087 * glue dir around in kernfs_new_node().
3089 * In order to avoid this happening, we also should make sure that
3090 * kernfs_node for glue_dir is released in CPU1 only when refcount
3091 * for glue_dir kobj is 1.
3093 ref = kref_read(&glue_dir->kref);
3094 if (!kobject_has_children(glue_dir) && !--ref)
3095 kobject_del(glue_dir);
3096 kobject_put(glue_dir);
3097 mutex_unlock(&gdp_mutex);
3100 static int device_add_class_symlinks(struct device *dev)
3102 struct device_node *of_node = dev_of_node(dev);
3106 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3108 dev_warn(dev, "Error %d creating of_node link\n",error);
3109 /* An error here doesn't warrant bringing down the device */
3115 error = sysfs_create_link(&dev->kobj,
3116 &dev->class->p->subsys.kobj,
3121 if (dev->parent && device_is_not_partition(dev)) {
3122 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3129 /* /sys/block has directories and does not need symlinks */
3130 if (sysfs_deprecated && dev->class == &block_class)
3134 /* link in the class directory pointing to the device */
3135 error = sysfs_create_link(&dev->class->p->subsys.kobj,
3136 &dev->kobj, dev_name(dev));
3143 sysfs_remove_link(&dev->kobj, "device");
3146 sysfs_remove_link(&dev->kobj, "subsystem");
3148 sysfs_remove_link(&dev->kobj, "of_node");
3152 static void device_remove_class_symlinks(struct device *dev)
3154 if (dev_of_node(dev))
3155 sysfs_remove_link(&dev->kobj, "of_node");
3160 if (dev->parent && device_is_not_partition(dev))
3161 sysfs_remove_link(&dev->kobj, "device");
3162 sysfs_remove_link(&dev->kobj, "subsystem");
3164 if (sysfs_deprecated && dev->class == &block_class)
3167 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
3171 * dev_set_name - set a device name
3173 * @fmt: format string for the device's name
3175 int dev_set_name(struct device *dev, const char *fmt, ...)
3180 va_start(vargs, fmt);
3181 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3185 EXPORT_SYMBOL_GPL(dev_set_name);
3188 * device_to_dev_kobj - select a /sys/dev/ directory for the device
3191 * By default we select char/ for new entries. Setting class->dev_obj
3192 * to NULL prevents an entry from being created. class->dev_kobj must
3193 * be set (or cleared) before any devices are registered to the class
3194 * otherwise device_create_sys_dev_entry() and
3195 * device_remove_sys_dev_entry() will disagree about the presence of
3198 static struct kobject *device_to_dev_kobj(struct device *dev)
3200 struct kobject *kobj;
3203 kobj = dev->class->dev_kobj;
3205 kobj = sysfs_dev_char_kobj;
3210 static int device_create_sys_dev_entry(struct device *dev)
3212 struct kobject *kobj = device_to_dev_kobj(dev);
3217 format_dev_t(devt_str, dev->devt);
3218 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3224 static void device_remove_sys_dev_entry(struct device *dev)
3226 struct kobject *kobj = device_to_dev_kobj(dev);
3230 format_dev_t(devt_str, dev->devt);
3231 sysfs_remove_link(kobj, devt_str);
3235 static int device_private_init(struct device *dev)
3237 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3240 dev->p->device = dev;
3241 klist_init(&dev->p->klist_children, klist_children_get,
3242 klist_children_put);
3243 INIT_LIST_HEAD(&dev->p->deferred_probe);
3248 * device_add - add device to device hierarchy.
3251 * This is part 2 of device_register(), though may be called
3252 * separately _iff_ device_initialize() has been called separately.
3254 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3255 * to the global and sibling lists for the device, then
3256 * adds it to the other relevant subsystems of the driver model.
3258 * Do not call this routine or device_register() more than once for
3259 * any device structure. The driver model core is not designed to work
3260 * with devices that get unregistered and then spring back to life.
3261 * (Among other things, it's very hard to guarantee that all references
3262 * to the previous incarnation of @dev have been dropped.) Allocate
3263 * and register a fresh new struct device instead.
3265 * NOTE: _Never_ directly free @dev after calling this function, even
3266 * if it returned an error! Always use put_device() to give up your
3267 * reference instead.
3269 * Rule of thumb is: if device_add() succeeds, you should call
3270 * device_del() when you want to get rid of it. If device_add() has
3271 * *not* succeeded, use *only* put_device() to drop the reference
3274 int device_add(struct device *dev)
3276 struct device *parent;
3277 struct kobject *kobj;
3278 struct class_interface *class_intf;
3279 int error = -EINVAL;
3280 struct kobject *glue_dir = NULL;
3282 dev = get_device(dev);
3287 error = device_private_init(dev);
3293 * for statically allocated devices, which should all be converted
3294 * some day, we need to initialize the name. We prevent reading back
3295 * the name, and force the use of dev_name()
3297 if (dev->init_name) {
3298 dev_set_name(dev, "%s", dev->init_name);
3299 dev->init_name = NULL;
3302 /* subsystems can specify simple device enumeration */
3303 if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
3304 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3306 if (!dev_name(dev)) {
3311 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3313 parent = get_device(dev->parent);
3314 kobj = get_device_parent(dev, parent);
3316 error = PTR_ERR(kobj);
3320 dev->kobj.parent = kobj;
3322 /* use parent numa_node */
3323 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3324 set_dev_node(dev, dev_to_node(parent));
3326 /* first, register with generic layer. */
3327 /* we require the name to be set before, and pass NULL */
3328 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3330 glue_dir = get_glue_dir(dev);
3334 /* notify platform of device entry */
3335 device_platform_notify(dev);
3337 error = device_create_file(dev, &dev_attr_uevent);
3341 error = device_add_class_symlinks(dev);
3344 error = device_add_attrs(dev);
3347 error = bus_add_device(dev);
3350 error = dpm_sysfs_add(dev);
3355 if (MAJOR(dev->devt)) {
3356 error = device_create_file(dev, &dev_attr_dev);
3360 error = device_create_sys_dev_entry(dev);
3364 devtmpfs_create_node(dev);
3367 /* Notify clients of device addition. This call must come
3368 * after dpm_sysfs_add() and before kobject_uevent().
3371 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3372 BUS_NOTIFY_ADD_DEVICE, dev);
3374 kobject_uevent(&dev->kobj, KOBJ_ADD);
3377 * Check if any of the other devices (consumers) have been waiting for
3378 * this device (supplier) to be added so that they can create a device
3381 * This needs to happen after device_pm_add() because device_link_add()
3382 * requires the supplier be registered before it's called.
3384 * But this also needs to happen before bus_probe_device() to make sure
3385 * waiting consumers can link to it before the driver is bound to the
3386 * device and the driver sync_state callback is called for this device.
3388 if (dev->fwnode && !dev->fwnode->dev) {
3389 dev->fwnode->dev = dev;
3390 fw_devlink_link_device(dev);
3393 bus_probe_device(dev);
3396 * If all driver registration is done and a newly added device doesn't
3397 * match with any driver, don't block its consumers from probing in
3398 * case the consumer device is able to operate without this supplier.
3400 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3401 fw_devlink_unblock_consumers(dev);
3404 klist_add_tail(&dev->p->knode_parent,
3405 &parent->p->klist_children);
3408 mutex_lock(&dev->class->p->mutex);
3409 /* tie the class to the device */
3410 klist_add_tail(&dev->p->knode_class,
3411 &dev->class->p->klist_devices);
3413 /* notify any interfaces that the device is here */
3414 list_for_each_entry(class_intf,
3415 &dev->class->p->interfaces, node)
3416 if (class_intf->add_dev)
3417 class_intf->add_dev(dev, class_intf);
3418 mutex_unlock(&dev->class->p->mutex);
3424 if (MAJOR(dev->devt))
3425 device_remove_file(dev, &dev_attr_dev);
3427 device_pm_remove(dev);
3428 dpm_sysfs_remove(dev);
3430 bus_remove_device(dev);
3432 device_remove_attrs(dev);
3434 device_remove_class_symlinks(dev);
3436 device_remove_file(dev, &dev_attr_uevent);
3438 device_platform_notify_remove(dev);
3439 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3440 glue_dir = get_glue_dir(dev);
3441 kobject_del(&dev->kobj);
3443 cleanup_glue_dir(dev, glue_dir);
3451 EXPORT_SYMBOL_GPL(device_add);
3454 * device_register - register a device with the system.
3455 * @dev: pointer to the device structure
3457 * This happens in two clean steps - initialize the device
3458 * and add it to the system. The two steps can be called
3459 * separately, but this is the easiest and most common.
3460 * I.e. you should only call the two helpers separately if
3461 * have a clearly defined need to use and refcount the device
3462 * before it is added to the hierarchy.
3464 * For more information, see the kerneldoc for device_initialize()
3467 * NOTE: _Never_ directly free @dev after calling this function, even
3468 * if it returned an error! Always use put_device() to give up the
3469 * reference initialized in this function instead.
3471 int device_register(struct device *dev)
3473 device_initialize(dev);
3474 return device_add(dev);
3476 EXPORT_SYMBOL_GPL(device_register);
3479 * get_device - increment reference count for device.
3482 * This simply forwards the call to kobject_get(), though
3483 * we do take care to provide for the case that we get a NULL
3484 * pointer passed in.
3486 struct device *get_device(struct device *dev)
3488 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3490 EXPORT_SYMBOL_GPL(get_device);
3493 * put_device - decrement reference count.
3494 * @dev: device in question.
3496 void put_device(struct device *dev)
3498 /* might_sleep(); */
3500 kobject_put(&dev->kobj);
3502 EXPORT_SYMBOL_GPL(put_device);
3504 bool kill_device(struct device *dev)
3507 * Require the device lock and set the "dead" flag to guarantee that
3508 * the update behavior is consistent with the other bitfields near
3509 * it and that we cannot have an asynchronous probe routine trying
3510 * to run while we are tearing out the bus/class/sysfs from
3511 * underneath the device.
3513 device_lock_assert(dev);
3517 dev->p->dead = true;
3520 EXPORT_SYMBOL_GPL(kill_device);
3523 * device_del - delete device from system.
3526 * This is the first part of the device unregistration
3527 * sequence. This removes the device from the lists we control
3528 * from here, has it removed from the other driver model
3529 * subsystems it was added to in device_add(), and removes it
3530 * from the kobject hierarchy.
3532 * NOTE: this should be called manually _iff_ device_add() was
3533 * also called manually.
3535 void device_del(struct device *dev)
3537 struct device *parent = dev->parent;
3538 struct kobject *glue_dir = NULL;
3539 struct class_interface *class_intf;
3540 unsigned int noio_flag;
3546 if (dev->fwnode && dev->fwnode->dev == dev)
3547 dev->fwnode->dev = NULL;
3549 /* Notify clients of device removal. This call must come
3550 * before dpm_sysfs_remove().
3552 noio_flag = memalloc_noio_save();
3554 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3555 BUS_NOTIFY_DEL_DEVICE, dev);
3557 dpm_sysfs_remove(dev);
3559 klist_del(&dev->p->knode_parent);
3560 if (MAJOR(dev->devt)) {
3561 devtmpfs_delete_node(dev);
3562 device_remove_sys_dev_entry(dev);
3563 device_remove_file(dev, &dev_attr_dev);
3566 device_remove_class_symlinks(dev);
3568 mutex_lock(&dev->class->p->mutex);
3569 /* notify any interfaces that the device is now gone */
3570 list_for_each_entry(class_intf,
3571 &dev->class->p->interfaces, node)
3572 if (class_intf->remove_dev)
3573 class_intf->remove_dev(dev, class_intf);
3574 /* remove the device from the class list */
3575 klist_del(&dev->p->knode_class);
3576 mutex_unlock(&dev->class->p->mutex);
3578 device_remove_file(dev, &dev_attr_uevent);
3579 device_remove_attrs(dev);
3580 bus_remove_device(dev);
3581 device_pm_remove(dev);
3582 driver_deferred_probe_del(dev);
3583 device_platform_notify_remove(dev);
3584 device_links_purge(dev);
3587 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
3588 BUS_NOTIFY_REMOVED_DEVICE, dev);
3589 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3590 glue_dir = get_glue_dir(dev);
3591 kobject_del(&dev->kobj);
3592 cleanup_glue_dir(dev, glue_dir);
3593 memalloc_noio_restore(noio_flag);
3596 EXPORT_SYMBOL_GPL(device_del);
3599 * device_unregister - unregister device from system.
3600 * @dev: device going away.
3602 * We do this in two parts, like we do device_register(). First,
3603 * we remove it from all the subsystems with device_del(), then
3604 * we decrement the reference count via put_device(). If that
3605 * is the final reference count, the device will be cleaned up
3606 * via device_release() above. Otherwise, the structure will
3607 * stick around until the final reference to the device is dropped.
3609 void device_unregister(struct device *dev)
3611 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3615 EXPORT_SYMBOL_GPL(device_unregister);
3617 static struct device *prev_device(struct klist_iter *i)
3619 struct klist_node *n = klist_prev(i);
3620 struct device *dev = NULL;
3621 struct device_private *p;
3624 p = to_device_private_parent(n);
3630 static struct device *next_device(struct klist_iter *i)
3632 struct klist_node *n = klist_next(i);
3633 struct device *dev = NULL;
3634 struct device_private *p;
3637 p = to_device_private_parent(n);
3644 * device_get_devnode - path of device node file
3646 * @mode: returned file access mode
3647 * @uid: returned file owner
3648 * @gid: returned file group
3649 * @tmp: possibly allocated string
3651 * Return the relative path of a possible device node.
3652 * Non-default names may need to allocate a memory to compose
3653 * a name. This memory is returned in tmp and needs to be
3654 * freed by the caller.
3656 const char *device_get_devnode(struct device *dev,
3657 umode_t *mode, kuid_t *uid, kgid_t *gid,
3664 /* the device type may provide a specific name */
3665 if (dev->type && dev->type->devnode)
3666 *tmp = dev->type->devnode(dev, mode, uid, gid);
3670 /* the class may provide a specific name */
3671 if (dev->class && dev->class->devnode)
3672 *tmp = dev->class->devnode(dev, mode);
3676 /* return name without allocation, tmp == NULL */
3677 if (strchr(dev_name(dev), '!') == NULL)
3678 return dev_name(dev);
3680 /* replace '!' in the name with '/' */
3681 s = kstrdup(dev_name(dev), GFP_KERNEL);
3684 strreplace(s, '!', '/');
3689 * device_for_each_child - device child iterator.
3690 * @parent: parent struct device.
3691 * @fn: function to be called for each device.
3692 * @data: data for the callback.
3694 * Iterate over @parent's child devices, and call @fn for each,
3697 * We check the return of @fn each time. If it returns anything
3698 * other than 0, we break out and return that value.
3700 int device_for_each_child(struct device *parent, void *data,
3701 int (*fn)(struct device *dev, void *data))
3703 struct klist_iter i;
3704 struct device *child;
3710 klist_iter_init(&parent->p->klist_children, &i);
3711 while (!error && (child = next_device(&i)))
3712 error = fn(child, data);
3713 klist_iter_exit(&i);
3716 EXPORT_SYMBOL_GPL(device_for_each_child);
3719 * device_for_each_child_reverse - device child iterator in reversed order.
3720 * @parent: parent struct device.
3721 * @fn: function to be called for each device.
3722 * @data: data for the callback.
3724 * Iterate over @parent's child devices, and call @fn for each,
3727 * We check the return of @fn each time. If it returns anything
3728 * other than 0, we break out and return that value.
3730 int device_for_each_child_reverse(struct device *parent, void *data,
3731 int (*fn)(struct device *dev, void *data))
3733 struct klist_iter i;
3734 struct device *child;
3740 klist_iter_init(&parent->p->klist_children, &i);
3741 while ((child = prev_device(&i)) && !error)
3742 error = fn(child, data);
3743 klist_iter_exit(&i);
3746 EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
3749 * device_find_child - device iterator for locating a particular device.
3750 * @parent: parent struct device
3751 * @match: Callback function to check device
3752 * @data: Data to pass to match function
3754 * This is similar to the device_for_each_child() function above, but it
3755 * returns a reference to a device that is 'found' for later use, as
3756 * determined by the @match callback.
3758 * The callback should return 0 if the device doesn't match and non-zero
3759 * if it does. If the callback returns non-zero and a reference to the
3760 * current device can be obtained, this function will return to the caller
3761 * and not iterate over any more devices.
3763 * NOTE: you will need to drop the reference with put_device() after use.
3765 struct device *device_find_child(struct device *parent, void *data,
3766 int (*match)(struct device *dev, void *data))
3768 struct klist_iter i;
3769 struct device *child;
3774 klist_iter_init(&parent->p->klist_children, &i);
3775 while ((child = next_device(&i)))
3776 if (match(child, data) && get_device(child))
3778 klist_iter_exit(&i);
3781 EXPORT_SYMBOL_GPL(device_find_child);
3784 * device_find_child_by_name - device iterator for locating a child device.
3785 * @parent: parent struct device
3786 * @name: name of the child device
3788 * This is similar to the device_find_child() function above, but it
3789 * returns a reference to a device that has the name @name.
3791 * NOTE: you will need to drop the reference with put_device() after use.
3793 struct device *device_find_child_by_name(struct device *parent,
3796 struct klist_iter i;
3797 struct device *child;
3802 klist_iter_init(&parent->p->klist_children, &i);
3803 while ((child = next_device(&i)))
3804 if (sysfs_streq(dev_name(child), name) && get_device(child))
3806 klist_iter_exit(&i);
3809 EXPORT_SYMBOL_GPL(device_find_child_by_name);
3811 int __init devices_init(void)
3813 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
3816 dev_kobj = kobject_create_and_add("dev", NULL);
3819 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
3820 if (!sysfs_dev_block_kobj)
3821 goto block_kobj_err;
3822 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
3823 if (!sysfs_dev_char_kobj)
3829 kobject_put(sysfs_dev_block_kobj);
3831 kobject_put(dev_kobj);
3833 kset_unregister(devices_kset);
3837 static int device_check_offline(struct device *dev, void *not_used)
3841 ret = device_for_each_child(dev, NULL, device_check_offline);
3845 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
3849 * device_offline - Prepare the device for hot-removal.
3850 * @dev: Device to be put offline.
3852 * Execute the device bus type's .offline() callback, if present, to prepare
3853 * the device for a subsequent hot-removal. If that succeeds, the device must
3854 * not be used until either it is removed or its bus type's .online() callback
3857 * Call under device_hotplug_lock.
3859 int device_offline(struct device *dev)
3863 if (dev->offline_disabled)
3866 ret = device_for_each_child(dev, NULL, device_check_offline);
3871 if (device_supports_offline(dev)) {
3875 ret = dev->bus->offline(dev);
3877 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
3878 dev->offline = true;
3888 * device_online - Put the device back online after successful device_offline().
3889 * @dev: Device to be put back online.
3891 * If device_offline() has been successfully executed for @dev, but the device
3892 * has not been removed subsequently, execute its bus type's .online() callback
3893 * to indicate that the device can be used again.
3895 * Call under device_hotplug_lock.
3897 int device_online(struct device *dev)
3902 if (device_supports_offline(dev)) {
3904 ret = dev->bus->online(dev);
3906 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
3907 dev->offline = false;
3918 struct root_device {
3920 struct module *owner;
3923 static inline struct root_device *to_root_device(struct device *d)
3925 return container_of(d, struct root_device, dev);
3928 static void root_device_release(struct device *dev)
3930 kfree(to_root_device(dev));
3934 * __root_device_register - allocate and register a root device
3935 * @name: root device name
3936 * @owner: owner module of the root device, usually THIS_MODULE
3938 * This function allocates a root device and registers it
3939 * using device_register(). In order to free the returned
3940 * device, use root_device_unregister().
3942 * Root devices are dummy devices which allow other devices
3943 * to be grouped under /sys/devices. Use this function to
3944 * allocate a root device and then use it as the parent of
3945 * any device which should appear under /sys/devices/{name}
3947 * The /sys/devices/{name} directory will also contain a
3948 * 'module' symlink which points to the @owner directory
3951 * Returns &struct device pointer on success, or ERR_PTR() on error.
3953 * Note: You probably want to use root_device_register().
3955 struct device *__root_device_register(const char *name, struct module *owner)
3957 struct root_device *root;
3960 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
3962 return ERR_PTR(err);
3964 err = dev_set_name(&root->dev, "%s", name);
3967 return ERR_PTR(err);
3970 root->dev.release = root_device_release;
3972 err = device_register(&root->dev);
3974 put_device(&root->dev);
3975 return ERR_PTR(err);
3978 #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
3980 struct module_kobject *mk = &owner->mkobj;
3982 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
3984 device_unregister(&root->dev);
3985 return ERR_PTR(err);
3987 root->owner = owner;
3993 EXPORT_SYMBOL_GPL(__root_device_register);
3996 * root_device_unregister - unregister and free a root device
3997 * @dev: device going away
3999 * This function unregisters and cleans up a device that was created by
4000 * root_device_register().
4002 void root_device_unregister(struct device *dev)
4004 struct root_device *root = to_root_device(dev);
4007 sysfs_remove_link(&root->dev.kobj, "module");
4009 device_unregister(dev);
4011 EXPORT_SYMBOL_GPL(root_device_unregister);
4014 static void device_create_release(struct device *dev)
4016 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4020 static __printf(6, 0) struct device *
4021 device_create_groups_vargs(struct class *class, struct device *parent,
4022 dev_t devt, void *drvdata,
4023 const struct attribute_group **groups,
4024 const char *fmt, va_list args)
4026 struct device *dev = NULL;
4027 int retval = -ENODEV;
4029 if (class == NULL || IS_ERR(class))
4032 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4038 device_initialize(dev);
4041 dev->parent = parent;
4042 dev->groups = groups;
4043 dev->release = device_create_release;
4044 dev_set_drvdata(dev, drvdata);
4046 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4050 retval = device_add(dev);
4058 return ERR_PTR(retval);
4062 * device_create - creates a device and registers it with sysfs
4063 * @class: pointer to the struct class that this device should be registered to
4064 * @parent: pointer to the parent struct device of this new device, if any
4065 * @devt: the dev_t for the char device to be added
4066 * @drvdata: the data to be added to the device for callbacks
4067 * @fmt: string for the device's name
4069 * This function can be used by char device classes. A struct device
4070 * will be created in sysfs, registered to the specified class.
4072 * A "dev" file will be created, showing the dev_t for the device, if
4073 * the dev_t is not 0,0.
4074 * If a pointer to a parent struct device is passed in, the newly created
4075 * struct device will be a child of that device in sysfs.
4076 * The pointer to the struct device will be returned from the call.
4077 * Any further sysfs files that might be required can be created using this
4080 * Returns &struct device pointer on success, or ERR_PTR() on error.
4082 * Note: the struct class passed to this function must have previously
4083 * been created with a call to class_create().
4085 struct device *device_create(struct class *class, struct device *parent,
4086 dev_t devt, void *drvdata, const char *fmt, ...)
4091 va_start(vargs, fmt);
4092 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4097 EXPORT_SYMBOL_GPL(device_create);
4100 * device_create_with_groups - creates a device and registers it with sysfs
4101 * @class: pointer to the struct class that this device should be registered to
4102 * @parent: pointer to the parent struct device of this new device, if any
4103 * @devt: the dev_t for the char device to be added
4104 * @drvdata: the data to be added to the device for callbacks
4105 * @groups: NULL-terminated list of attribute groups to be created
4106 * @fmt: string for the device's name
4108 * This function can be used by char device classes. A struct device
4109 * will be created in sysfs, registered to the specified class.
4110 * Additional attributes specified in the groups parameter will also
4111 * be created automatically.
4113 * A "dev" file will be created, showing the dev_t for the device, if
4114 * the dev_t is not 0,0.
4115 * If a pointer to a parent struct device is passed in, the newly created
4116 * struct device will be a child of that device in sysfs.
4117 * The pointer to the struct device will be returned from the call.
4118 * Any further sysfs files that might be required can be created using this
4121 * Returns &struct device pointer on success, or ERR_PTR() on error.
4123 * Note: the struct class passed to this function must have previously
4124 * been created with a call to class_create().
4126 struct device *device_create_with_groups(struct class *class,
4127 struct device *parent, dev_t devt,
4129 const struct attribute_group **groups,
4130 const char *fmt, ...)
4135 va_start(vargs, fmt);
4136 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4141 EXPORT_SYMBOL_GPL(device_create_with_groups);
4144 * device_destroy - removes a device that was created with device_create()
4145 * @class: pointer to the struct class that this device was registered with
4146 * @devt: the dev_t of the device that was previously registered
4148 * This call unregisters and cleans up a device that was created with a
4149 * call to device_create().
4151 void device_destroy(struct class *class, dev_t devt)
4155 dev = class_find_device_by_devt(class, devt);
4158 device_unregister(dev);
4161 EXPORT_SYMBOL_GPL(device_destroy);
4164 * device_rename - renames a device
4165 * @dev: the pointer to the struct device to be renamed
4166 * @new_name: the new name of the device
4168 * It is the responsibility of the caller to provide mutual
4169 * exclusion between two different calls of device_rename
4170 * on the same device to ensure that new_name is valid and
4171 * won't conflict with other devices.
4173 * Note: Don't call this function. Currently, the networking layer calls this
4174 * function, but that will change. The following text from Kay Sievers offers
4177 * Renaming devices is racy at many levels, symlinks and other stuff are not
4178 * replaced atomically, and you get a "move" uevent, but it's not easy to
4179 * connect the event to the old and new device. Device nodes are not renamed at
4180 * all, there isn't even support for that in the kernel now.
4182 * In the meantime, during renaming, your target name might be taken by another
4183 * driver, creating conflicts. Or the old name is taken directly after you
4184 * renamed it -- then you get events for the same DEVPATH, before you even see
4185 * the "move" event. It's just a mess, and nothing new should ever rely on
4186 * kernel device renaming. Besides that, it's not even implemented now for
4187 * other things than (driver-core wise very simple) network devices.
4189 * We are currently about to change network renaming in udev to completely
4190 * disallow renaming of devices in the same namespace as the kernel uses,
4191 * because we can't solve the problems properly, that arise with swapping names
4192 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
4193 * be allowed to some other name than eth[0-9]*, for the aforementioned
4196 * Make up a "real" name in the driver before you register anything, or add
4197 * some other attributes for userspace to find the device, or use udev to add
4198 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4199 * don't even want to get into that and try to implement the missing pieces in
4200 * the core. We really have other pieces to fix in the driver core mess. :)
4202 int device_rename(struct device *dev, const char *new_name)
4204 struct kobject *kobj = &dev->kobj;
4205 char *old_device_name = NULL;
4208 dev = get_device(dev);
4212 dev_dbg(dev, "renaming to %s\n", new_name);
4214 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4215 if (!old_device_name) {
4221 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj,
4222 kobj, old_device_name,
4223 new_name, kobject_namespace(kobj));
4228 error = kobject_rename(kobj, new_name);
4235 kfree(old_device_name);
4239 EXPORT_SYMBOL_GPL(device_rename);
4241 static int device_move_class_links(struct device *dev,
4242 struct device *old_parent,
4243 struct device *new_parent)
4248 sysfs_remove_link(&dev->kobj, "device");
4250 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4256 * device_move - moves a device to a new parent
4257 * @dev: the pointer to the struct device to be moved
4258 * @new_parent: the new parent of the device (can be NULL)
4259 * @dpm_order: how to reorder the dpm_list
4261 int device_move(struct device *dev, struct device *new_parent,
4262 enum dpm_order dpm_order)
4265 struct device *old_parent;
4266 struct kobject *new_parent_kobj;
4268 dev = get_device(dev);
4273 new_parent = get_device(new_parent);
4274 new_parent_kobj = get_device_parent(dev, new_parent);
4275 if (IS_ERR(new_parent_kobj)) {
4276 error = PTR_ERR(new_parent_kobj);
4277 put_device(new_parent);
4281 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4282 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4283 error = kobject_move(&dev->kobj, new_parent_kobj);
4285 cleanup_glue_dir(dev, new_parent_kobj);
4286 put_device(new_parent);
4289 old_parent = dev->parent;
4290 dev->parent = new_parent;
4292 klist_remove(&dev->p->knode_parent);
4294 klist_add_tail(&dev->p->knode_parent,
4295 &new_parent->p->klist_children);
4296 set_dev_node(dev, dev_to_node(new_parent));
4300 error = device_move_class_links(dev, old_parent, new_parent);
4302 /* We ignore errors on cleanup since we're hosed anyway... */
4303 device_move_class_links(dev, new_parent, old_parent);
4304 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4306 klist_remove(&dev->p->knode_parent);
4307 dev->parent = old_parent;
4309 klist_add_tail(&dev->p->knode_parent,
4310 &old_parent->p->klist_children);
4311 set_dev_node(dev, dev_to_node(old_parent));
4314 cleanup_glue_dir(dev, new_parent_kobj);
4315 put_device(new_parent);
4319 switch (dpm_order) {
4320 case DPM_ORDER_NONE:
4322 case DPM_ORDER_DEV_AFTER_PARENT:
4323 device_pm_move_after(dev, new_parent);
4324 devices_kset_move_after(dev, new_parent);
4326 case DPM_ORDER_PARENT_BEFORE_DEV:
4327 device_pm_move_before(new_parent, dev);
4328 devices_kset_move_before(new_parent, dev);
4330 case DPM_ORDER_DEV_LAST:
4331 device_pm_move_last(dev);
4332 devices_kset_move_last(dev);
4336 put_device(old_parent);
4342 EXPORT_SYMBOL_GPL(device_move);
4344 static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4347 struct kobject *kobj = &dev->kobj;
4348 struct class *class = dev->class;
4349 const struct device_type *type = dev->type;
4354 * Change the device groups of the device class for @dev to
4357 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4365 * Change the device groups of the device type for @dev to
4368 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4374 /* Change the device groups of @dev to @kuid/@kgid. */
4375 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4379 if (device_supports_offline(dev) && !dev->offline_disabled) {
4380 /* Change online device attributes of @dev to @kuid/@kgid. */
4381 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4391 * device_change_owner - change the owner of an existing device.
4393 * @kuid: new owner's kuid
4394 * @kgid: new owner's kgid
4396 * This changes the owner of @dev and its corresponding sysfs entries to
4397 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4400 * Returns 0 on success or error code on failure.
4402 int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4405 struct kobject *kobj = &dev->kobj;
4407 dev = get_device(dev);
4412 * Change the kobject and the default attributes and groups of the
4413 * ktype associated with it to @kuid/@kgid.
4415 error = sysfs_change_owner(kobj, kuid, kgid);
4420 * Change the uevent file for @dev to the new owner. The uevent file
4421 * was created in a separate step when @dev got added and we mirror
4424 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4430 * Change the device groups, the device groups associated with the
4431 * device class, and the groups associated with the device type of @dev
4434 error = device_attrs_change_owner(dev, kuid, kgid);
4438 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4443 if (sysfs_deprecated && dev->class == &block_class)
4448 * Change the owner of the symlink located in the class directory of
4449 * the device class associated with @dev which points to the actual
4450 * directory entry for @dev to @kuid/@kgid. This ensures that the
4451 * symlink shows the same permissions as its target.
4453 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj,
4454 dev_name(dev), kuid, kgid);
4462 EXPORT_SYMBOL_GPL(device_change_owner);
4465 * device_shutdown - call ->shutdown() on each device to shutdown.
4467 void device_shutdown(void)
4469 struct device *dev, *parent;
4471 wait_for_device_probe();
4472 device_block_probing();
4476 spin_lock(&devices_kset->list_lock);
4478 * Walk the devices list backward, shutting down each in turn.
4479 * Beware that device unplug events may also start pulling
4480 * devices offline, even as the system is shutting down.
4482 while (!list_empty(&devices_kset->list)) {
4483 dev = list_entry(devices_kset->list.prev, struct device,
4487 * hold reference count of device's parent to
4488 * prevent it from being freed because parent's
4489 * lock is to be held
4491 parent = get_device(dev->parent);
4494 * Make sure the device is off the kset list, in the
4495 * event that dev->*->shutdown() doesn't remove it.
4497 list_del_init(&dev->kobj.entry);
4498 spin_unlock(&devices_kset->list_lock);
4500 /* hold lock to avoid race with probe/release */
4502 device_lock(parent);
4505 /* Don't allow any more runtime suspends */
4506 pm_runtime_get_noresume(dev);
4507 pm_runtime_barrier(dev);
4509 if (dev->class && dev->class->shutdown_pre) {
4511 dev_info(dev, "shutdown_pre\n");
4512 dev->class->shutdown_pre(dev);
4514 if (dev->bus && dev->bus->shutdown) {
4516 dev_info(dev, "shutdown\n");
4517 dev->bus->shutdown(dev);
4518 } else if (dev->driver && dev->driver->shutdown) {
4520 dev_info(dev, "shutdown\n");
4521 dev->driver->shutdown(dev);
4526 device_unlock(parent);
4531 spin_lock(&devices_kset->list_lock);
4533 spin_unlock(&devices_kset->list_lock);
4537 * Device logging functions
4540 #ifdef CONFIG_PRINTK
4542 set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4546 memset(dev_info, 0, sizeof(*dev_info));
4549 subsys = dev->class->name;
4551 subsys = dev->bus->name;
4555 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4558 * Add device identifier DEVICE=:
4562 * +sound:card0 subsystem:devname
4564 if (MAJOR(dev->devt)) {
4567 if (strcmp(subsys, "block") == 0)
4572 snprintf(dev_info->device, sizeof(dev_info->device),
4573 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4574 } else if (strcmp(subsys, "net") == 0) {
4575 struct net_device *net = to_net_dev(dev);
4577 snprintf(dev_info->device, sizeof(dev_info->device),
4578 "n%u", net->ifindex);
4580 snprintf(dev_info->device, sizeof(dev_info->device),
4581 "+%s:%s", subsys, dev_name(dev));
4585 int dev_vprintk_emit(int level, const struct device *dev,
4586 const char *fmt, va_list args)
4588 struct dev_printk_info dev_info;
4590 set_dev_info(dev, &dev_info);
4592 return vprintk_emit(0, level, &dev_info, fmt, args);
4594 EXPORT_SYMBOL(dev_vprintk_emit);
4596 int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4601 va_start(args, fmt);
4603 r = dev_vprintk_emit(level, dev, fmt, args);
4609 EXPORT_SYMBOL(dev_printk_emit);
4611 static void __dev_printk(const char *level, const struct device *dev,
4612 struct va_format *vaf)
4615 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4616 dev_driver_string(dev), dev_name(dev), vaf);
4618 printk("%s(NULL device *): %pV", level, vaf);
4621 void _dev_printk(const char *level, const struct device *dev,
4622 const char *fmt, ...)
4624 struct va_format vaf;
4627 va_start(args, fmt);
4632 __dev_printk(level, dev, &vaf);
4636 EXPORT_SYMBOL(_dev_printk);
4638 #define define_dev_printk_level(func, kern_level) \
4639 void func(const struct device *dev, const char *fmt, ...) \
4641 struct va_format vaf; \
4644 va_start(args, fmt); \
4649 __dev_printk(kern_level, dev, &vaf); \
4653 EXPORT_SYMBOL(func);
4655 define_dev_printk_level(_dev_emerg, KERN_EMERG);
4656 define_dev_printk_level(_dev_alert, KERN_ALERT);
4657 define_dev_printk_level(_dev_crit, KERN_CRIT);
4658 define_dev_printk_level(_dev_err, KERN_ERR);
4659 define_dev_printk_level(_dev_warn, KERN_WARNING);
4660 define_dev_printk_level(_dev_notice, KERN_NOTICE);
4661 define_dev_printk_level(_dev_info, KERN_INFO);
4666 * dev_err_probe - probe error check and log helper
4667 * @dev: the pointer to the struct device
4668 * @err: error value to test
4669 * @fmt: printf-style format string
4670 * @...: arguments as specified in the format string
4672 * This helper implements common pattern present in probe functions for error
4673 * checking: print debug or error message depending if the error value is
4674 * -EPROBE_DEFER and propagate error upwards.
4675 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4676 * checked later by reading devices_deferred debugfs attribute.
4677 * It replaces code sequence::
4679 * if (err != -EPROBE_DEFER)
4680 * dev_err(dev, ...);
4682 * dev_dbg(dev, ...);
4687 * return dev_err_probe(dev, err, ...);
4689 * Note that it is deemed acceptable to use this function for error
4690 * prints during probe even if the @err is known to never be -EPROBE_DEFER.
4691 * The benefit compared to a normal dev_err() is the standardized format
4692 * of the error code and the fact that the error code is returned.
4697 int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4699 struct va_format vaf;
4702 va_start(args, fmt);
4706 if (err != -EPROBE_DEFER) {
4707 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4709 device_set_deferred_probe_reason(dev, &vaf);
4710 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4717 EXPORT_SYMBOL_GPL(dev_err_probe);
4719 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4721 return fwnode && !IS_ERR(fwnode->secondary);
4725 * set_primary_fwnode - Change the primary firmware node of a given device.
4726 * @dev: Device to handle.
4727 * @fwnode: New primary firmware node of the device.
4729 * Set the device's firmware node pointer to @fwnode, but if a secondary
4730 * firmware node of the device is present, preserve it.
4732 * Valid fwnode cases are:
4733 * - primary --> secondary --> -ENODEV
4734 * - primary --> NULL
4735 * - secondary --> -ENODEV
4738 void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4740 struct device *parent = dev->parent;
4741 struct fwnode_handle *fn = dev->fwnode;
4744 if (fwnode_is_primary(fn))
4748 WARN_ON(fwnode->secondary);
4749 fwnode->secondary = fn;
4751 dev->fwnode = fwnode;
4753 if (fwnode_is_primary(fn)) {
4754 dev->fwnode = fn->secondary;
4755 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
4756 if (!(parent && fn == parent->fwnode))
4757 fn->secondary = NULL;
4763 EXPORT_SYMBOL_GPL(set_primary_fwnode);
4766 * set_secondary_fwnode - Change the secondary firmware node of a given device.
4767 * @dev: Device to handle.
4768 * @fwnode: New secondary firmware node of the device.
4770 * If a primary firmware node of the device is present, set its secondary
4771 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
4774 void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
4777 fwnode->secondary = ERR_PTR(-ENODEV);
4779 if (fwnode_is_primary(dev->fwnode))
4780 dev->fwnode->secondary = fwnode;
4782 dev->fwnode = fwnode;
4784 EXPORT_SYMBOL_GPL(set_secondary_fwnode);
4787 * device_set_of_node_from_dev - reuse device-tree node of another device
4788 * @dev: device whose device-tree node is being set
4789 * @dev2: device whose device-tree node is being reused
4791 * Takes another reference to the new device-tree node after first dropping
4792 * any reference held to the old node.
4794 void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
4796 of_node_put(dev->of_node);
4797 dev->of_node = of_node_get(dev2->of_node);
4798 dev->of_node_reused = true;
4800 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
4802 void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
4804 dev->fwnode = fwnode;
4805 dev->of_node = to_of_node(fwnode);
4807 EXPORT_SYMBOL_GPL(device_set_node);
4809 int device_match_name(struct device *dev, const void *name)
4811 return sysfs_streq(dev_name(dev), name);
4813 EXPORT_SYMBOL_GPL(device_match_name);
4815 int device_match_of_node(struct device *dev, const void *np)
4817 return dev->of_node == np;
4819 EXPORT_SYMBOL_GPL(device_match_of_node);
4821 int device_match_fwnode(struct device *dev, const void *fwnode)
4823 return dev_fwnode(dev) == fwnode;
4825 EXPORT_SYMBOL_GPL(device_match_fwnode);
4827 int device_match_devt(struct device *dev, const void *pdevt)
4829 return dev->devt == *(dev_t *)pdevt;
4831 EXPORT_SYMBOL_GPL(device_match_devt);
4833 int device_match_acpi_dev(struct device *dev, const void *adev)
4835 return ACPI_COMPANION(dev) == adev;
4837 EXPORT_SYMBOL(device_match_acpi_dev);
4839 int device_match_acpi_handle(struct device *dev, const void *handle)
4841 return ACPI_HANDLE(dev) == handle;
4843 EXPORT_SYMBOL(device_match_acpi_handle);
4845 int device_match_any(struct device *dev, const void *unused)
4849 EXPORT_SYMBOL_GPL(device_match_any);