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/kstrtox.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
20 #include <linux/kdev_t.h>
21 #include <linux/notifier.h>
23 #include <linux/of_device.h>
24 #include <linux/blkdev.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/string_helpers.h>
31 #include <linux/swiotlb.h>
32 #include <linux/sysfs.h>
33 #include <linux/dma-map-ops.h> /* for dma_default_coherent */
36 #include "physical_location.h"
37 #include "power/power.h"
39 /* Device links support. */
40 static LIST_HEAD(deferred_sync);
41 static unsigned int defer_sync_state_count = 1;
42 static DEFINE_MUTEX(fwnode_link_lock);
43 static bool fw_devlink_is_permissive(void);
44 static void __fw_devlink_link_to_consumers(struct device *dev);
45 static bool fw_devlink_drv_reg_done;
46 static bool fw_devlink_best_effort;
49 * __fwnode_link_add - Create a link between two fwnode_handles.
50 * @con: Consumer end of the link.
51 * @sup: Supplier end of the link.
54 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
55 * represents the detail that the firmware lists @sup fwnode as supplying a
58 * The driver core will use the fwnode link to create a device link between the
59 * two device objects corresponding to @con and @sup when they are created. The
60 * driver core will automatically delete the fwnode link between @con and @sup
63 * Attempts to create duplicate links between the same pair of fwnode handles
64 * are ignored and there is no reference counting.
66 static int __fwnode_link_add(struct fwnode_handle *con,
67 struct fwnode_handle *sup, u8 flags)
69 struct fwnode_link *link;
71 list_for_each_entry(link, &sup->consumers, s_hook)
72 if (link->consumer == con) {
77 link = kzalloc(sizeof(*link), GFP_KERNEL);
82 INIT_LIST_HEAD(&link->s_hook);
84 INIT_LIST_HEAD(&link->c_hook);
87 list_add(&link->s_hook, &sup->consumers);
88 list_add(&link->c_hook, &con->suppliers);
89 pr_debug("%pfwf Linked as a fwnode consumer to %pfwf\n",
95 int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
99 mutex_lock(&fwnode_link_lock);
100 ret = __fwnode_link_add(con, sup, 0);
101 mutex_unlock(&fwnode_link_lock);
106 * __fwnode_link_del - Delete a link between two fwnode_handles.
107 * @link: the fwnode_link to be deleted
109 * The fwnode_link_lock needs to be held when this function is called.
111 static void __fwnode_link_del(struct fwnode_link *link)
113 pr_debug("%pfwf Dropping the fwnode link to %pfwf\n",
114 link->consumer, link->supplier);
115 list_del(&link->s_hook);
116 list_del(&link->c_hook);
121 * __fwnode_link_cycle - Mark a fwnode link as being part of a cycle.
122 * @link: the fwnode_link to be marked
124 * The fwnode_link_lock needs to be held when this function is called.
126 static void __fwnode_link_cycle(struct fwnode_link *link)
128 pr_debug("%pfwf: cycle: depends on %pfwf\n",
129 link->consumer, link->supplier);
130 link->flags |= FWLINK_FLAG_CYCLE;
134 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
135 * @fwnode: fwnode whose supplier links need to be deleted
137 * Deletes all supplier links connecting directly to @fwnode.
139 static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
141 struct fwnode_link *link, *tmp;
143 mutex_lock(&fwnode_link_lock);
144 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
145 __fwnode_link_del(link);
146 mutex_unlock(&fwnode_link_lock);
150 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
151 * @fwnode: fwnode whose consumer links need to be deleted
153 * Deletes all consumer links connecting directly to @fwnode.
155 static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
157 struct fwnode_link *link, *tmp;
159 mutex_lock(&fwnode_link_lock);
160 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
161 __fwnode_link_del(link);
162 mutex_unlock(&fwnode_link_lock);
166 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
167 * @fwnode: fwnode whose links needs to be deleted
169 * Deletes all links connecting directly to a fwnode.
171 void fwnode_links_purge(struct fwnode_handle *fwnode)
173 fwnode_links_purge_suppliers(fwnode);
174 fwnode_links_purge_consumers(fwnode);
177 void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
179 struct fwnode_handle *child;
181 /* Don't purge consumer links of an added child */
185 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
186 fwnode_links_purge_consumers(fwnode);
188 fwnode_for_each_available_child_node(fwnode, child)
189 fw_devlink_purge_absent_suppliers(child);
191 EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
194 * __fwnode_links_move_consumers - Move consumer from @from to @to fwnode_handle
195 * @from: move consumers away from this fwnode
196 * @to: move consumers to this fwnode
198 * Move all consumer links from @from fwnode to @to fwnode.
200 static void __fwnode_links_move_consumers(struct fwnode_handle *from,
201 struct fwnode_handle *to)
203 struct fwnode_link *link, *tmp;
205 list_for_each_entry_safe(link, tmp, &from->consumers, s_hook) {
206 __fwnode_link_add(link->consumer, to, link->flags);
207 __fwnode_link_del(link);
212 * __fw_devlink_pickup_dangling_consumers - Pick up dangling consumers
213 * @fwnode: fwnode from which to pick up dangling consumers
214 * @new_sup: fwnode of new supplier
216 * If the @fwnode has a corresponding struct device and the device supports
217 * probing (that is, added to a bus), then we want to let fw_devlink create
218 * MANAGED device links to this device, so leave @fwnode and its descendant's
219 * fwnode links alone.
221 * Otherwise, move its consumers to the new supplier @new_sup.
223 static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode,
224 struct fwnode_handle *new_sup)
226 struct fwnode_handle *child;
228 if (fwnode->dev && fwnode->dev->bus)
231 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
232 __fwnode_links_move_consumers(fwnode, new_sup);
234 fwnode_for_each_available_child_node(fwnode, child)
235 __fw_devlink_pickup_dangling_consumers(child, new_sup);
238 static DEFINE_MUTEX(device_links_lock);
239 DEFINE_STATIC_SRCU(device_links_srcu);
241 static inline void device_links_write_lock(void)
243 mutex_lock(&device_links_lock);
246 static inline void device_links_write_unlock(void)
248 mutex_unlock(&device_links_lock);
251 int device_links_read_lock(void) __acquires(&device_links_srcu)
253 return srcu_read_lock(&device_links_srcu);
256 void device_links_read_unlock(int idx) __releases(&device_links_srcu)
258 srcu_read_unlock(&device_links_srcu, idx);
261 int device_links_read_lock_held(void)
263 return srcu_read_lock_held(&device_links_srcu);
266 static void device_link_synchronize_removal(void)
268 synchronize_srcu(&device_links_srcu);
271 static void device_link_remove_from_lists(struct device_link *link)
273 list_del_rcu(&link->s_node);
274 list_del_rcu(&link->c_node);
277 static bool device_is_ancestor(struct device *dev, struct device *target)
279 while (target->parent) {
280 target = target->parent;
287 #define DL_MARKER_FLAGS (DL_FLAG_INFERRED | \
290 static inline bool device_link_flag_is_sync_state_only(u32 flags)
292 return (flags & ~DL_MARKER_FLAGS) == DL_FLAG_SYNC_STATE_ONLY;
296 * device_is_dependent - Check if one device depends on another one
297 * @dev: Device to check dependencies for.
298 * @target: Device to check against.
300 * Check if @target depends on @dev or any device dependent on it (its child or
301 * its consumer etc). Return 1 if that is the case or 0 otherwise.
303 static int device_is_dependent(struct device *dev, void *target)
305 struct device_link *link;
309 * The "ancestors" check is needed to catch the case when the target
310 * device has not been completely initialized yet and it is still
311 * missing from the list of children of its parent device.
313 if (dev == target || device_is_ancestor(dev, target))
316 ret = device_for_each_child(dev, target, device_is_dependent);
320 list_for_each_entry(link, &dev->links.consumers, s_node) {
321 if (device_link_flag_is_sync_state_only(link->flags))
324 if (link->consumer == target)
327 ret = device_is_dependent(link->consumer, target);
334 static void device_link_init_status(struct device_link *link,
335 struct device *consumer,
336 struct device *supplier)
338 switch (supplier->links.status) {
340 switch (consumer->links.status) {
343 * A consumer driver can create a link to a supplier
344 * that has not completed its probing yet as long as it
345 * knows that the supplier is already functional (for
346 * example, it has just acquired some resources from the
349 link->status = DL_STATE_CONSUMER_PROBE;
352 link->status = DL_STATE_DORMANT;
356 case DL_DEV_DRIVER_BOUND:
357 switch (consumer->links.status) {
359 link->status = DL_STATE_CONSUMER_PROBE;
361 case DL_DEV_DRIVER_BOUND:
362 link->status = DL_STATE_ACTIVE;
365 link->status = DL_STATE_AVAILABLE;
369 case DL_DEV_UNBINDING:
370 link->status = DL_STATE_SUPPLIER_UNBIND;
373 link->status = DL_STATE_DORMANT;
378 static int device_reorder_to_tail(struct device *dev, void *not_used)
380 struct device_link *link;
383 * Devices that have not been registered yet will be put to the ends
384 * of the lists during the registration, so skip them here.
386 if (device_is_registered(dev))
387 devices_kset_move_last(dev);
389 if (device_pm_initialized(dev))
390 device_pm_move_last(dev);
392 device_for_each_child(dev, NULL, device_reorder_to_tail);
393 list_for_each_entry(link, &dev->links.consumers, s_node) {
394 if (device_link_flag_is_sync_state_only(link->flags))
396 device_reorder_to_tail(link->consumer, NULL);
403 * device_pm_move_to_tail - Move set of devices to the end of device lists
404 * @dev: Device to move
406 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
408 * It moves the @dev along with all of its children and all of its consumers
409 * to the ends of the device_kset and dpm_list, recursively.
411 void device_pm_move_to_tail(struct device *dev)
415 idx = device_links_read_lock();
417 device_reorder_to_tail(dev, NULL);
419 device_links_read_unlock(idx);
422 #define to_devlink(dev) container_of((dev), struct device_link, link_dev)
424 static ssize_t status_show(struct device *dev,
425 struct device_attribute *attr, char *buf)
429 switch (to_devlink(dev)->status) {
431 output = "not tracked";
433 case DL_STATE_DORMANT:
436 case DL_STATE_AVAILABLE:
437 output = "available";
439 case DL_STATE_CONSUMER_PROBE:
440 output = "consumer probing";
442 case DL_STATE_ACTIVE:
445 case DL_STATE_SUPPLIER_UNBIND:
446 output = "supplier unbinding";
453 return sysfs_emit(buf, "%s\n", output);
455 static DEVICE_ATTR_RO(status);
457 static ssize_t auto_remove_on_show(struct device *dev,
458 struct device_attribute *attr, char *buf)
460 struct device_link *link = to_devlink(dev);
463 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
464 output = "supplier unbind";
465 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
466 output = "consumer unbind";
470 return sysfs_emit(buf, "%s\n", output);
472 static DEVICE_ATTR_RO(auto_remove_on);
474 static ssize_t runtime_pm_show(struct device *dev,
475 struct device_attribute *attr, char *buf)
477 struct device_link *link = to_devlink(dev);
479 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
481 static DEVICE_ATTR_RO(runtime_pm);
483 static ssize_t sync_state_only_show(struct device *dev,
484 struct device_attribute *attr, char *buf)
486 struct device_link *link = to_devlink(dev);
488 return sysfs_emit(buf, "%d\n",
489 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
491 static DEVICE_ATTR_RO(sync_state_only);
493 static struct attribute *devlink_attrs[] = {
494 &dev_attr_status.attr,
495 &dev_attr_auto_remove_on.attr,
496 &dev_attr_runtime_pm.attr,
497 &dev_attr_sync_state_only.attr,
500 ATTRIBUTE_GROUPS(devlink);
502 static void device_link_release_fn(struct work_struct *work)
504 struct device_link *link = container_of(work, struct device_link, rm_work);
506 /* Ensure that all references to the link object have been dropped. */
507 device_link_synchronize_removal();
509 pm_runtime_release_supplier(link);
511 * If supplier_preactivated is set, the link has been dropped between
512 * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
513 * in __driver_probe_device(). In that case, drop the supplier's
514 * PM-runtime usage counter to remove the reference taken by
515 * pm_runtime_get_suppliers().
517 if (link->supplier_preactivated)
518 pm_runtime_put_noidle(link->supplier);
520 pm_request_idle(link->supplier);
522 put_device(link->consumer);
523 put_device(link->supplier);
527 static void devlink_dev_release(struct device *dev)
529 struct device_link *link = to_devlink(dev);
531 INIT_WORK(&link->rm_work, device_link_release_fn);
533 * It may take a while to complete this work because of the SRCU
534 * synchronization in device_link_release_fn() and if the consumer or
535 * supplier devices get deleted when it runs, so put it into the "long"
538 queue_work(system_long_wq, &link->rm_work);
541 static struct class devlink_class = {
543 .dev_groups = devlink_groups,
544 .dev_release = devlink_dev_release,
547 static int devlink_add_symlinks(struct device *dev)
551 struct device_link *link = to_devlink(dev);
552 struct device *sup = link->supplier;
553 struct device *con = link->consumer;
556 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
557 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
559 len += strlen("supplier:") + 1;
560 buf = kzalloc(len, GFP_KERNEL);
564 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
568 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
572 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
573 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
577 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
578 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
585 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
586 sysfs_remove_link(&sup->kobj, buf);
588 sysfs_remove_link(&link->link_dev.kobj, "consumer");
590 sysfs_remove_link(&link->link_dev.kobj, "supplier");
596 static void devlink_remove_symlinks(struct device *dev)
598 struct device_link *link = to_devlink(dev);
600 struct device *sup = link->supplier;
601 struct device *con = link->consumer;
604 sysfs_remove_link(&link->link_dev.kobj, "consumer");
605 sysfs_remove_link(&link->link_dev.kobj, "supplier");
607 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
608 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
610 len += strlen("supplier:") + 1;
611 buf = kzalloc(len, GFP_KERNEL);
613 WARN(1, "Unable to properly free device link symlinks!\n");
617 if (device_is_registered(con)) {
618 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
619 sysfs_remove_link(&con->kobj, buf);
621 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
622 sysfs_remove_link(&sup->kobj, buf);
626 static struct class_interface devlink_class_intf = {
627 .class = &devlink_class,
628 .add_dev = devlink_add_symlinks,
629 .remove_dev = devlink_remove_symlinks,
632 static int __init devlink_class_init(void)
636 ret = class_register(&devlink_class);
640 ret = class_interface_register(&devlink_class_intf);
642 class_unregister(&devlink_class);
646 postcore_initcall(devlink_class_init);
648 #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
649 DL_FLAG_AUTOREMOVE_SUPPLIER | \
650 DL_FLAG_AUTOPROBE_CONSUMER | \
651 DL_FLAG_SYNC_STATE_ONLY | \
655 #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
656 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
659 * device_link_add - Create a link between two devices.
660 * @consumer: Consumer end of the link.
661 * @supplier: Supplier end of the link.
662 * @flags: Link flags.
664 * The caller is responsible for the proper synchronization of the link creation
665 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
666 * runtime PM framework to take the link into account. Second, if the
667 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
668 * be forced into the active meta state and reference-counted upon the creation
669 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
672 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
673 * expected to release the link returned by it directly with the help of either
674 * device_link_del() or device_link_remove().
676 * If that flag is not set, however, the caller of this function is handing the
677 * management of the link over to the driver core entirely and its return value
678 * can only be used to check whether or not the link is present. In that case,
679 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
680 * flags can be used to indicate to the driver core when the link can be safely
681 * deleted. Namely, setting one of them in @flags indicates to the driver core
682 * that the link is not going to be used (by the given caller of this function)
683 * after unbinding the consumer or supplier driver, respectively, from its
684 * device, so the link can be deleted at that point. If none of them is set,
685 * the link will be maintained until one of the devices pointed to by it (either
686 * the consumer or the supplier) is unregistered.
688 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
689 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
690 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
691 * be used to request the driver core to automatically probe for a consumer
692 * driver after successfully binding a driver to the supplier device.
694 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
695 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
696 * the same time is invalid and will cause NULL to be returned upfront.
697 * However, if a device link between the given @consumer and @supplier pair
698 * exists already when this function is called for them, the existing link will
699 * be returned regardless of its current type and status (the link's flags may
700 * be modified then). The caller of this function is then expected to treat
701 * the link as though it has just been created, so (in particular) if
702 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
703 * explicitly when not needed any more (as stated above).
705 * A side effect of the link creation is re-ordering of dpm_list and the
706 * devices_kset list by moving the consumer device and all devices depending
707 * on it to the ends of these lists (that does not happen to devices that have
708 * not been registered when this function is called).
710 * The supplier device is required to be registered when this function is called
711 * and NULL will be returned if that is not the case. The consumer device need
712 * not be registered, however.
714 struct device_link *device_link_add(struct device *consumer,
715 struct device *supplier, u32 flags)
717 struct device_link *link;
719 if (!consumer || !supplier || consumer == supplier ||
720 flags & ~DL_ADD_VALID_FLAGS ||
721 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
722 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
723 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
724 DL_FLAG_AUTOREMOVE_SUPPLIER)))
727 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
728 if (pm_runtime_get_sync(supplier) < 0) {
729 pm_runtime_put_noidle(supplier);
734 if (!(flags & DL_FLAG_STATELESS))
735 flags |= DL_FLAG_MANAGED;
737 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
738 !device_link_flag_is_sync_state_only(flags))
741 device_links_write_lock();
745 * If the supplier has not been fully registered yet or there is a
746 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
747 * the supplier already in the graph, return NULL. If the link is a
748 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
749 * because it only affects sync_state() callbacks.
751 if (!device_pm_initialized(supplier)
752 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
753 device_is_dependent(consumer, supplier))) {
759 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
760 * So, only create it if the consumer hasn't probed yet.
762 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
763 consumer->links.status != DL_DEV_NO_DRIVER &&
764 consumer->links.status != DL_DEV_PROBING) {
770 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
771 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
772 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
774 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
775 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
777 list_for_each_entry(link, &supplier->links.consumers, s_node) {
778 if (link->consumer != consumer)
781 if (link->flags & DL_FLAG_INFERRED &&
782 !(flags & DL_FLAG_INFERRED))
783 link->flags &= ~DL_FLAG_INFERRED;
785 if (flags & DL_FLAG_PM_RUNTIME) {
786 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
787 pm_runtime_new_link(consumer);
788 link->flags |= DL_FLAG_PM_RUNTIME;
790 if (flags & DL_FLAG_RPM_ACTIVE)
791 refcount_inc(&link->rpm_active);
794 if (flags & DL_FLAG_STATELESS) {
795 kref_get(&link->kref);
796 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
797 !(link->flags & DL_FLAG_STATELESS)) {
798 link->flags |= DL_FLAG_STATELESS;
801 link->flags |= DL_FLAG_STATELESS;
807 * If the life time of the link following from the new flags is
808 * longer than indicated by the flags of the existing link,
809 * update the existing link to stay around longer.
811 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
812 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
813 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
814 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
816 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
817 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
818 DL_FLAG_AUTOREMOVE_SUPPLIER);
820 if (!(link->flags & DL_FLAG_MANAGED)) {
821 kref_get(&link->kref);
822 link->flags |= DL_FLAG_MANAGED;
823 device_link_init_status(link, consumer, supplier);
825 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
826 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
827 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
834 link = kzalloc(sizeof(*link), GFP_KERNEL);
838 refcount_set(&link->rpm_active, 1);
840 get_device(supplier);
841 link->supplier = supplier;
842 INIT_LIST_HEAD(&link->s_node);
843 get_device(consumer);
844 link->consumer = consumer;
845 INIT_LIST_HEAD(&link->c_node);
847 kref_init(&link->kref);
849 link->link_dev.class = &devlink_class;
850 device_set_pm_not_required(&link->link_dev);
851 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
852 dev_bus_name(supplier), dev_name(supplier),
853 dev_bus_name(consumer), dev_name(consumer));
854 if (device_register(&link->link_dev)) {
855 put_device(&link->link_dev);
860 if (flags & DL_FLAG_PM_RUNTIME) {
861 if (flags & DL_FLAG_RPM_ACTIVE)
862 refcount_inc(&link->rpm_active);
864 pm_runtime_new_link(consumer);
867 /* Determine the initial link state. */
868 if (flags & DL_FLAG_STATELESS)
869 link->status = DL_STATE_NONE;
871 device_link_init_status(link, consumer, supplier);
874 * Some callers expect the link creation during consumer driver probe to
875 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
877 if (link->status == DL_STATE_CONSUMER_PROBE &&
878 flags & DL_FLAG_PM_RUNTIME)
879 pm_runtime_resume(supplier);
881 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
882 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
884 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
886 "Linked as a sync state only consumer to %s\n",
893 * Move the consumer and all of the devices depending on it to the end
894 * of dpm_list and the devices_kset list.
896 * It is necessary to hold dpm_list locked throughout all that or else
897 * we may end up suspending with a wrong ordering of it.
899 device_reorder_to_tail(consumer, NULL);
901 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
905 device_links_write_unlock();
907 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
908 pm_runtime_put(supplier);
912 EXPORT_SYMBOL_GPL(device_link_add);
914 static void __device_link_del(struct kref *kref)
916 struct device_link *link = container_of(kref, struct device_link, kref);
918 dev_dbg(link->consumer, "Dropping the link to %s\n",
919 dev_name(link->supplier));
921 pm_runtime_drop_link(link);
923 device_link_remove_from_lists(link);
924 device_unregister(&link->link_dev);
927 static void device_link_put_kref(struct device_link *link)
929 if (link->flags & DL_FLAG_STATELESS)
930 kref_put(&link->kref, __device_link_del);
931 else if (!device_is_registered(link->consumer))
932 __device_link_del(&link->kref);
934 WARN(1, "Unable to drop a managed device link reference\n");
938 * device_link_del - Delete a stateless link between two devices.
939 * @link: Device link to delete.
941 * The caller must ensure proper synchronization of this function with runtime
942 * PM. If the link was added multiple times, it needs to be deleted as often.
943 * Care is required for hotplugged devices: Their links are purged on removal
944 * and calling device_link_del() is then no longer allowed.
946 void device_link_del(struct device_link *link)
948 device_links_write_lock();
949 device_link_put_kref(link);
950 device_links_write_unlock();
952 EXPORT_SYMBOL_GPL(device_link_del);
955 * device_link_remove - Delete a stateless link between two devices.
956 * @consumer: Consumer end of the link.
957 * @supplier: Supplier end of the link.
959 * The caller must ensure proper synchronization of this function with runtime
962 void device_link_remove(void *consumer, struct device *supplier)
964 struct device_link *link;
966 if (WARN_ON(consumer == supplier))
969 device_links_write_lock();
971 list_for_each_entry(link, &supplier->links.consumers, s_node) {
972 if (link->consumer == consumer) {
973 device_link_put_kref(link);
978 device_links_write_unlock();
980 EXPORT_SYMBOL_GPL(device_link_remove);
982 static void device_links_missing_supplier(struct device *dev)
984 struct device_link *link;
986 list_for_each_entry(link, &dev->links.suppliers, c_node) {
987 if (link->status != DL_STATE_CONSUMER_PROBE)
990 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
991 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
993 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
994 WRITE_ONCE(link->status, DL_STATE_DORMANT);
999 static bool dev_is_best_effort(struct device *dev)
1001 return (fw_devlink_best_effort && dev->can_match) ||
1002 (dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
1005 static struct fwnode_handle *fwnode_links_check_suppliers(
1006 struct fwnode_handle *fwnode)
1008 struct fwnode_link *link;
1010 if (!fwnode || fw_devlink_is_permissive())
1013 list_for_each_entry(link, &fwnode->suppliers, c_hook)
1014 if (!(link->flags & FWLINK_FLAG_CYCLE))
1015 return link->supplier;
1021 * device_links_check_suppliers - Check presence of supplier drivers.
1022 * @dev: Consumer device.
1024 * Check links from this device to any suppliers. Walk the list of the device's
1025 * links to suppliers and see if all of them are available. If not, simply
1026 * return -EPROBE_DEFER.
1028 * We need to guarantee that the supplier will not go away after the check has
1029 * been positive here. It only can go away in __device_release_driver() and
1030 * that function checks the device's links to consumers. This means we need to
1031 * mark the link as "consumer probe in progress" to make the supplier removal
1032 * wait for us to complete (or bad things may happen).
1034 * Links without the DL_FLAG_MANAGED flag set are ignored.
1036 int device_links_check_suppliers(struct device *dev)
1038 struct device_link *link;
1039 int ret = 0, fwnode_ret = 0;
1040 struct fwnode_handle *sup_fw;
1043 * Device waiting for supplier to become available is not allowed to
1046 mutex_lock(&fwnode_link_lock);
1047 sup_fw = fwnode_links_check_suppliers(dev->fwnode);
1049 if (!dev_is_best_effort(dev)) {
1050 fwnode_ret = -EPROBE_DEFER;
1051 dev_err_probe(dev, -EPROBE_DEFER,
1052 "wait for supplier %pfwf\n", sup_fw);
1054 fwnode_ret = -EAGAIN;
1057 mutex_unlock(&fwnode_link_lock);
1058 if (fwnode_ret == -EPROBE_DEFER)
1061 device_links_write_lock();
1063 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1064 if (!(link->flags & DL_FLAG_MANAGED))
1067 if (link->status != DL_STATE_AVAILABLE &&
1068 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1070 if (dev_is_best_effort(dev) &&
1071 link->flags & DL_FLAG_INFERRED &&
1072 !link->supplier->can_match) {
1077 device_links_missing_supplier(dev);
1078 dev_err_probe(dev, -EPROBE_DEFER,
1079 "supplier %s not ready\n",
1080 dev_name(link->supplier));
1081 ret = -EPROBE_DEFER;
1084 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1086 dev->links.status = DL_DEV_PROBING;
1088 device_links_write_unlock();
1090 return ret ? ret : fwnode_ret;
1094 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1095 * @dev: Device to call sync_state() on
1096 * @list: List head to queue the @dev on
1098 * Queues a device for a sync_state() callback when the device links write lock
1099 * isn't held. This allows the sync_state() execution flow to use device links
1100 * APIs. The caller must ensure this function is called with
1101 * device_links_write_lock() held.
1103 * This function does a get_device() to make sure the device is not freed while
1106 * So the caller must also ensure that device_links_flush_sync_list() is called
1107 * as soon as the caller releases device_links_write_lock(). This is necessary
1108 * to make sure the sync_state() is called in a timely fashion and the
1109 * put_device() is called on this device.
1111 static void __device_links_queue_sync_state(struct device *dev,
1112 struct list_head *list)
1114 struct device_link *link;
1116 if (!dev_has_sync_state(dev))
1118 if (dev->state_synced)
1121 list_for_each_entry(link, &dev->links.consumers, s_node) {
1122 if (!(link->flags & DL_FLAG_MANAGED))
1124 if (link->status != DL_STATE_ACTIVE)
1129 * Set the flag here to avoid adding the same device to a list more
1130 * than once. This can happen if new consumers get added to the device
1131 * and probed before the list is flushed.
1133 dev->state_synced = true;
1135 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1139 list_add_tail(&dev->links.defer_sync, list);
1143 * device_links_flush_sync_list - Call sync_state() on a list of devices
1144 * @list: List of devices to call sync_state() on
1145 * @dont_lock_dev: Device for which lock is already held by the caller
1147 * Calls sync_state() on all the devices that have been queued for it. This
1148 * function is used in conjunction with __device_links_queue_sync_state(). The
1149 * @dont_lock_dev parameter is useful when this function is called from a
1150 * context where a device lock is already held.
1152 static void device_links_flush_sync_list(struct list_head *list,
1153 struct device *dont_lock_dev)
1155 struct device *dev, *tmp;
1157 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1158 list_del_init(&dev->links.defer_sync);
1160 if (dev != dont_lock_dev)
1163 dev_sync_state(dev);
1165 if (dev != dont_lock_dev)
1172 void device_links_supplier_sync_state_pause(void)
1174 device_links_write_lock();
1175 defer_sync_state_count++;
1176 device_links_write_unlock();
1179 void device_links_supplier_sync_state_resume(void)
1181 struct device *dev, *tmp;
1182 LIST_HEAD(sync_list);
1184 device_links_write_lock();
1185 if (!defer_sync_state_count) {
1186 WARN(true, "Unmatched sync_state pause/resume!");
1189 defer_sync_state_count--;
1190 if (defer_sync_state_count)
1193 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1195 * Delete from deferred_sync list before queuing it to
1196 * sync_list because defer_sync is used for both lists.
1198 list_del_init(&dev->links.defer_sync);
1199 __device_links_queue_sync_state(dev, &sync_list);
1202 device_links_write_unlock();
1204 device_links_flush_sync_list(&sync_list, NULL);
1207 static int sync_state_resume_initcall(void)
1209 device_links_supplier_sync_state_resume();
1212 late_initcall(sync_state_resume_initcall);
1214 static void __device_links_supplier_defer_sync(struct device *sup)
1216 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1217 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1220 static void device_link_drop_managed(struct device_link *link)
1222 link->flags &= ~DL_FLAG_MANAGED;
1223 WRITE_ONCE(link->status, DL_STATE_NONE);
1224 kref_put(&link->kref, __device_link_del);
1227 static ssize_t waiting_for_supplier_show(struct device *dev,
1228 struct device_attribute *attr,
1234 mutex_lock(&fwnode_link_lock);
1235 val = !!fwnode_links_check_suppliers(dev->fwnode);
1236 mutex_unlock(&fwnode_link_lock);
1238 return sysfs_emit(buf, "%u\n", val);
1240 static DEVICE_ATTR_RO(waiting_for_supplier);
1243 * device_links_force_bind - Prepares device to be force bound
1244 * @dev: Consumer device.
1246 * device_bind_driver() force binds a device to a driver without calling any
1247 * driver probe functions. So the consumer really isn't going to wait for any
1248 * supplier before it's bound to the driver. We still want the device link
1249 * states to be sensible when this happens.
1251 * In preparation for device_bind_driver(), this function goes through each
1252 * supplier device links and checks if the supplier is bound. If it is, then
1253 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1254 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1256 void device_links_force_bind(struct device *dev)
1258 struct device_link *link, *ln;
1260 device_links_write_lock();
1262 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1263 if (!(link->flags & DL_FLAG_MANAGED))
1266 if (link->status != DL_STATE_AVAILABLE) {
1267 device_link_drop_managed(link);
1270 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1272 dev->links.status = DL_DEV_PROBING;
1274 device_links_write_unlock();
1278 * device_links_driver_bound - Update device links after probing its driver.
1279 * @dev: Device to update the links for.
1281 * The probe has been successful, so update links from this device to any
1282 * consumers by changing their status to "available".
1284 * Also change the status of @dev's links to suppliers to "active".
1286 * Links without the DL_FLAG_MANAGED flag set are ignored.
1288 void device_links_driver_bound(struct device *dev)
1290 struct device_link *link, *ln;
1291 LIST_HEAD(sync_list);
1294 * If a device binds successfully, it's expected to have created all
1295 * the device links it needs to or make new device links as it needs
1296 * them. So, fw_devlink no longer needs to create device links to any
1297 * of the device's suppliers.
1299 * Also, if a child firmware node of this bound device is not added as a
1300 * device by now, assume it is never going to be added. Make this bound
1301 * device the fallback supplier to the dangling consumers of the child
1302 * firmware node because this bound device is probably implementing the
1303 * child firmware node functionality and we don't want the dangling
1304 * consumers to defer probe indefinitely waiting for a device for the
1305 * child firmware node.
1307 if (dev->fwnode && dev->fwnode->dev == dev) {
1308 struct fwnode_handle *child;
1309 fwnode_links_purge_suppliers(dev->fwnode);
1310 mutex_lock(&fwnode_link_lock);
1311 fwnode_for_each_available_child_node(dev->fwnode, child)
1312 __fw_devlink_pickup_dangling_consumers(child,
1314 __fw_devlink_link_to_consumers(dev);
1315 mutex_unlock(&fwnode_link_lock);
1317 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1319 device_links_write_lock();
1321 list_for_each_entry(link, &dev->links.consumers, s_node) {
1322 if (!(link->flags & DL_FLAG_MANAGED))
1326 * Links created during consumer probe may be in the "consumer
1327 * probe" state to start with if the supplier is still probing
1328 * when they are created and they may become "active" if the
1329 * consumer probe returns first. Skip them here.
1331 if (link->status == DL_STATE_CONSUMER_PROBE ||
1332 link->status == DL_STATE_ACTIVE)
1335 WARN_ON(link->status != DL_STATE_DORMANT);
1336 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1338 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1339 driver_deferred_probe_add(link->consumer);
1342 if (defer_sync_state_count)
1343 __device_links_supplier_defer_sync(dev);
1345 __device_links_queue_sync_state(dev, &sync_list);
1347 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1348 struct device *supplier;
1350 if (!(link->flags & DL_FLAG_MANAGED))
1353 supplier = link->supplier;
1354 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1356 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1357 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1358 * save to drop the managed link completely.
1360 device_link_drop_managed(link);
1361 } else if (dev_is_best_effort(dev) &&
1362 link->flags & DL_FLAG_INFERRED &&
1363 link->status != DL_STATE_CONSUMER_PROBE &&
1364 !link->supplier->can_match) {
1366 * When dev_is_best_effort() is true, we ignore device
1367 * links to suppliers that don't have a driver. If the
1368 * consumer device still managed to probe, there's no
1369 * point in maintaining a device link in a weird state
1370 * (consumer probed before supplier). So delete it.
1372 device_link_drop_managed(link);
1374 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1375 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1379 * This needs to be done even for the deleted
1380 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1381 * device link that was preventing the supplier from getting a
1382 * sync_state() call.
1384 if (defer_sync_state_count)
1385 __device_links_supplier_defer_sync(supplier);
1387 __device_links_queue_sync_state(supplier, &sync_list);
1390 dev->links.status = DL_DEV_DRIVER_BOUND;
1392 device_links_write_unlock();
1394 device_links_flush_sync_list(&sync_list, dev);
1398 * __device_links_no_driver - Update links of a device without a driver.
1399 * @dev: Device without a drvier.
1401 * Delete all non-persistent links from this device to any suppliers.
1403 * Persistent links stay around, but their status is changed to "available",
1404 * unless they already are in the "supplier unbind in progress" state in which
1405 * case they need not be updated.
1407 * Links without the DL_FLAG_MANAGED flag set are ignored.
1409 static void __device_links_no_driver(struct device *dev)
1411 struct device_link *link, *ln;
1413 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1414 if (!(link->flags & DL_FLAG_MANAGED))
1417 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1418 device_link_drop_managed(link);
1422 if (link->status != DL_STATE_CONSUMER_PROBE &&
1423 link->status != DL_STATE_ACTIVE)
1426 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1427 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1429 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1430 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1434 dev->links.status = DL_DEV_NO_DRIVER;
1438 * device_links_no_driver - Update links after failing driver probe.
1439 * @dev: Device whose driver has just failed to probe.
1441 * Clean up leftover links to consumers for @dev and invoke
1442 * %__device_links_no_driver() to update links to suppliers for it as
1445 * Links without the DL_FLAG_MANAGED flag set are ignored.
1447 void device_links_no_driver(struct device *dev)
1449 struct device_link *link;
1451 device_links_write_lock();
1453 list_for_each_entry(link, &dev->links.consumers, s_node) {
1454 if (!(link->flags & DL_FLAG_MANAGED))
1458 * The probe has failed, so if the status of the link is
1459 * "consumer probe" or "active", it must have been added by
1460 * a probing consumer while this device was still probing.
1461 * Change its state to "dormant", as it represents a valid
1462 * relationship, but it is not functionally meaningful.
1464 if (link->status == DL_STATE_CONSUMER_PROBE ||
1465 link->status == DL_STATE_ACTIVE)
1466 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1469 __device_links_no_driver(dev);
1471 device_links_write_unlock();
1475 * device_links_driver_cleanup - Update links after driver removal.
1476 * @dev: Device whose driver has just gone away.
1478 * Update links to consumers for @dev by changing their status to "dormant" and
1479 * invoke %__device_links_no_driver() to update links to suppliers for it as
1482 * Links without the DL_FLAG_MANAGED flag set are ignored.
1484 void device_links_driver_cleanup(struct device *dev)
1486 struct device_link *link, *ln;
1488 device_links_write_lock();
1490 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1491 if (!(link->flags & DL_FLAG_MANAGED))
1494 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1495 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1498 * autoremove the links between this @dev and its consumer
1499 * devices that are not active, i.e. where the link state
1500 * has moved to DL_STATE_SUPPLIER_UNBIND.
1502 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1503 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1504 device_link_drop_managed(link);
1506 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1509 list_del_init(&dev->links.defer_sync);
1510 __device_links_no_driver(dev);
1512 device_links_write_unlock();
1516 * device_links_busy - Check if there are any busy links to consumers.
1517 * @dev: Device to check.
1519 * Check each consumer of the device and return 'true' if its link's status
1520 * is one of "consumer probe" or "active" (meaning that the given consumer is
1521 * probing right now or its driver is present). Otherwise, change the link
1522 * state to "supplier unbind" to prevent the consumer from being probed
1523 * successfully going forward.
1525 * Return 'false' if there are no probing or active consumers.
1527 * Links without the DL_FLAG_MANAGED flag set are ignored.
1529 bool device_links_busy(struct device *dev)
1531 struct device_link *link;
1534 device_links_write_lock();
1536 list_for_each_entry(link, &dev->links.consumers, s_node) {
1537 if (!(link->flags & DL_FLAG_MANAGED))
1540 if (link->status == DL_STATE_CONSUMER_PROBE
1541 || link->status == DL_STATE_ACTIVE) {
1545 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1548 dev->links.status = DL_DEV_UNBINDING;
1550 device_links_write_unlock();
1555 * device_links_unbind_consumers - Force unbind consumers of the given device.
1556 * @dev: Device to unbind the consumers of.
1558 * Walk the list of links to consumers for @dev and if any of them is in the
1559 * "consumer probe" state, wait for all device probes in progress to complete
1562 * If that's not the case, change the status of the link to "supplier unbind"
1563 * and check if the link was in the "active" state. If so, force the consumer
1564 * driver to unbind and start over (the consumer will not re-probe as we have
1565 * changed the state of the link already).
1567 * Links without the DL_FLAG_MANAGED flag set are ignored.
1569 void device_links_unbind_consumers(struct device *dev)
1571 struct device_link *link;
1574 device_links_write_lock();
1576 list_for_each_entry(link, &dev->links.consumers, s_node) {
1577 enum device_link_state status;
1579 if (!(link->flags & DL_FLAG_MANAGED) ||
1580 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1583 status = link->status;
1584 if (status == DL_STATE_CONSUMER_PROBE) {
1585 device_links_write_unlock();
1587 wait_for_device_probe();
1590 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1591 if (status == DL_STATE_ACTIVE) {
1592 struct device *consumer = link->consumer;
1594 get_device(consumer);
1596 device_links_write_unlock();
1598 device_release_driver_internal(consumer, NULL,
1600 put_device(consumer);
1605 device_links_write_unlock();
1609 * device_links_purge - Delete existing links to other devices.
1610 * @dev: Target device.
1612 static void device_links_purge(struct device *dev)
1614 struct device_link *link, *ln;
1616 if (dev->class == &devlink_class)
1620 * Delete all of the remaining links from this device to any other
1621 * devices (either consumers or suppliers).
1623 device_links_write_lock();
1625 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1626 WARN_ON(link->status == DL_STATE_ACTIVE);
1627 __device_link_del(&link->kref);
1630 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1631 WARN_ON(link->status != DL_STATE_DORMANT &&
1632 link->status != DL_STATE_NONE);
1633 __device_link_del(&link->kref);
1636 device_links_write_unlock();
1639 #define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1640 DL_FLAG_SYNC_STATE_ONLY)
1641 #define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1642 DL_FLAG_AUTOPROBE_CONSUMER)
1643 #define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1646 static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1647 static int __init fw_devlink_setup(char *arg)
1652 if (strcmp(arg, "off") == 0) {
1653 fw_devlink_flags = 0;
1654 } else if (strcmp(arg, "permissive") == 0) {
1655 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1656 } else if (strcmp(arg, "on") == 0) {
1657 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1658 } else if (strcmp(arg, "rpm") == 0) {
1659 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1663 early_param("fw_devlink", fw_devlink_setup);
1665 static bool fw_devlink_strict;
1666 static int __init fw_devlink_strict_setup(char *arg)
1668 return kstrtobool(arg, &fw_devlink_strict);
1670 early_param("fw_devlink.strict", fw_devlink_strict_setup);
1672 #define FW_DEVLINK_SYNC_STATE_STRICT 0
1673 #define FW_DEVLINK_SYNC_STATE_TIMEOUT 1
1675 #ifndef CONFIG_FW_DEVLINK_SYNC_STATE_TIMEOUT
1676 static int fw_devlink_sync_state;
1678 static int fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1681 static int __init fw_devlink_sync_state_setup(char *arg)
1686 if (strcmp(arg, "strict") == 0) {
1687 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_STRICT;
1689 } else if (strcmp(arg, "timeout") == 0) {
1690 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1695 early_param("fw_devlink.sync_state", fw_devlink_sync_state_setup);
1697 static inline u32 fw_devlink_get_flags(u8 fwlink_flags)
1699 if (fwlink_flags & FWLINK_FLAG_CYCLE)
1700 return FW_DEVLINK_FLAGS_PERMISSIVE | DL_FLAG_CYCLE;
1702 return fw_devlink_flags;
1705 static bool fw_devlink_is_permissive(void)
1707 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1710 bool fw_devlink_is_strict(void)
1712 return fw_devlink_strict && !fw_devlink_is_permissive();
1715 static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1717 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1720 fwnode_call_int_op(fwnode, add_links);
1721 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1724 static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1726 struct fwnode_handle *child = NULL;
1728 fw_devlink_parse_fwnode(fwnode);
1730 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1731 fw_devlink_parse_fwtree(child);
1734 static void fw_devlink_relax_link(struct device_link *link)
1736 if (!(link->flags & DL_FLAG_INFERRED))
1739 if (device_link_flag_is_sync_state_only(link->flags))
1742 pm_runtime_drop_link(link);
1743 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1744 dev_dbg(link->consumer, "Relaxing link with %s\n",
1745 dev_name(link->supplier));
1748 static int fw_devlink_no_driver(struct device *dev, void *data)
1750 struct device_link *link = to_devlink(dev);
1752 if (!link->supplier->can_match)
1753 fw_devlink_relax_link(link);
1758 void fw_devlink_drivers_done(void)
1760 fw_devlink_drv_reg_done = true;
1761 device_links_write_lock();
1762 class_for_each_device(&devlink_class, NULL, NULL,
1763 fw_devlink_no_driver);
1764 device_links_write_unlock();
1767 static int fw_devlink_dev_sync_state(struct device *dev, void *data)
1769 struct device_link *link = to_devlink(dev);
1770 struct device *sup = link->supplier;
1772 if (!(link->flags & DL_FLAG_MANAGED) ||
1773 link->status == DL_STATE_ACTIVE || sup->state_synced ||
1774 !dev_has_sync_state(sup))
1777 if (fw_devlink_sync_state == FW_DEVLINK_SYNC_STATE_STRICT) {
1778 dev_warn(sup, "sync_state() pending due to %s\n",
1779 dev_name(link->consumer));
1783 if (!list_empty(&sup->links.defer_sync))
1786 dev_warn(sup, "Timed out. Forcing sync_state()\n");
1787 sup->state_synced = true;
1789 list_add_tail(&sup->links.defer_sync, data);
1794 void fw_devlink_probing_done(void)
1796 LIST_HEAD(sync_list);
1798 device_links_write_lock();
1799 class_for_each_device(&devlink_class, NULL, &sync_list,
1800 fw_devlink_dev_sync_state);
1801 device_links_write_unlock();
1802 device_links_flush_sync_list(&sync_list, NULL);
1806 * wait_for_init_devices_probe - Try to probe any device needed for init
1808 * Some devices might need to be probed and bound successfully before the kernel
1809 * boot sequence can finish and move on to init/userspace. For example, a
1810 * network interface might need to be bound to be able to mount a NFS rootfs.
1812 * With fw_devlink=on by default, some of these devices might be blocked from
1813 * probing because they are waiting on a optional supplier that doesn't have a
1814 * driver. While fw_devlink will eventually identify such devices and unblock
1815 * the probing automatically, it might be too late by the time it unblocks the
1816 * probing of devices. For example, the IP4 autoconfig might timeout before
1817 * fw_devlink unblocks probing of the network interface.
1819 * This function is available to temporarily try and probe all devices that have
1820 * a driver even if some of their suppliers haven't been added or don't have
1823 * The drivers can then decide which of the suppliers are optional vs mandatory
1824 * and probe the device if possible. By the time this function returns, all such
1825 * "best effort" probes are guaranteed to be completed. If a device successfully
1826 * probes in this mode, we delete all fw_devlink discovered dependencies of that
1827 * device where the supplier hasn't yet probed successfully because they have to
1828 * be optional dependencies.
1830 * Any devices that didn't successfully probe go back to being treated as if
1831 * this function was never called.
1833 * This also means that some devices that aren't needed for init and could have
1834 * waited for their optional supplier to probe (when the supplier's module is
1835 * loaded later on) would end up probing prematurely with limited functionality.
1836 * So call this function only when boot would fail without it.
1838 void __init wait_for_init_devices_probe(void)
1840 if (!fw_devlink_flags || fw_devlink_is_permissive())
1844 * Wait for all ongoing probes to finish so that the "best effort" is
1845 * only applied to devices that can't probe otherwise.
1847 wait_for_device_probe();
1849 pr_info("Trying to probe devices needed for running init ...\n");
1850 fw_devlink_best_effort = true;
1851 driver_deferred_probe_trigger();
1854 * Wait for all "best effort" probes to finish before going back to
1855 * normal enforcement.
1857 wait_for_device_probe();
1858 fw_devlink_best_effort = false;
1861 static void fw_devlink_unblock_consumers(struct device *dev)
1863 struct device_link *link;
1865 if (!fw_devlink_flags || fw_devlink_is_permissive())
1868 device_links_write_lock();
1869 list_for_each_entry(link, &dev->links.consumers, s_node)
1870 fw_devlink_relax_link(link);
1871 device_links_write_unlock();
1875 static bool fwnode_init_without_drv(struct fwnode_handle *fwnode)
1880 if (!(fwnode->flags & FWNODE_FLAG_INITIALIZED))
1883 dev = get_dev_from_fwnode(fwnode);
1884 ret = !dev || dev->links.status == DL_DEV_NO_DRIVER;
1890 static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
1892 struct fwnode_handle *parent;
1894 fwnode_for_each_parent_node(fwnode, parent) {
1895 if (fwnode_init_without_drv(parent)) {
1896 fwnode_handle_put(parent);
1905 * __fw_devlink_relax_cycles - Relax and mark dependency cycles.
1906 * @con: Potential consumer device.
1907 * @sup_handle: Potential supplier's fwnode.
1909 * Needs to be called with fwnode_lock and device link lock held.
1911 * Check if @sup_handle or any of its ancestors or suppliers direct/indirectly
1912 * depend on @con. This function can detect multiple cyles between @sup_handle
1913 * and @con. When such dependency cycles are found, convert all device links
1914 * created solely by fw_devlink into SYNC_STATE_ONLY device links. Also, mark
1915 * all fwnode links in the cycle with FWLINK_FLAG_CYCLE so that when they are
1916 * converted into a device link in the future, they are created as
1917 * SYNC_STATE_ONLY device links. This is the equivalent of doing
1918 * fw_devlink=permissive just between the devices in the cycle. We need to do
1919 * this because, at this point, fw_devlink can't tell which of these
1920 * dependencies is not a real dependency.
1922 * Return true if one or more cycles were found. Otherwise, return false.
1924 static bool __fw_devlink_relax_cycles(struct device *con,
1925 struct fwnode_handle *sup_handle)
1927 struct device *sup_dev = NULL, *par_dev = NULL;
1928 struct fwnode_link *link;
1929 struct device_link *dev_link;
1936 * We aren't trying to find all cycles. Just a cycle between con and
1939 if (sup_handle->flags & FWNODE_FLAG_VISITED)
1942 sup_handle->flags |= FWNODE_FLAG_VISITED;
1944 sup_dev = get_dev_from_fwnode(sup_handle);
1946 /* Termination condition. */
1947 if (sup_dev == con) {
1948 pr_debug("----- cycle: start -----\n");
1954 * If sup_dev is bound to a driver and @con hasn't started binding to a
1955 * driver, sup_dev can't be a consumer of @con. So, no need to check
1958 if (sup_dev && sup_dev->links.status == DL_DEV_DRIVER_BOUND &&
1959 con->links.status == DL_DEV_NO_DRIVER) {
1964 list_for_each_entry(link, &sup_handle->suppliers, c_hook) {
1965 if (__fw_devlink_relax_cycles(con, link->supplier)) {
1966 __fwnode_link_cycle(link);
1972 * Give priority to device parent over fwnode parent to account for any
1973 * quirks in how fwnodes are converted to devices.
1976 par_dev = get_device(sup_dev->parent);
1978 par_dev = fwnode_get_next_parent_dev(sup_handle);
1980 if (par_dev && __fw_devlink_relax_cycles(con, par_dev->fwnode)) {
1981 pr_debug("%pfwf: cycle: child of %pfwf\n", sup_handle,
1989 list_for_each_entry(dev_link, &sup_dev->links.suppliers, c_node) {
1991 * Ignore a SYNC_STATE_ONLY flag only if it wasn't marked as
1992 * such due to a cycle.
1994 if (device_link_flag_is_sync_state_only(dev_link->flags) &&
1995 !(dev_link->flags & DL_FLAG_CYCLE))
1998 if (__fw_devlink_relax_cycles(con,
1999 dev_link->supplier->fwnode)) {
2000 pr_debug("%pfwf: cycle: depends on %pfwf\n", sup_handle,
2001 dev_link->supplier->fwnode);
2002 fw_devlink_relax_link(dev_link);
2003 dev_link->flags |= DL_FLAG_CYCLE;
2009 sup_handle->flags &= ~FWNODE_FLAG_VISITED;
2010 put_device(sup_dev);
2011 put_device(par_dev);
2016 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
2017 * @con: consumer device for the device link
2018 * @sup_handle: fwnode handle of supplier
2019 * @link: fwnode link that's being converted to a device link
2021 * This function will try to create a device link between the consumer device
2022 * @con and the supplier device represented by @sup_handle.
2024 * The supplier has to be provided as a fwnode because incorrect cycles in
2025 * fwnode links can sometimes cause the supplier device to never be created.
2026 * This function detects such cases and returns an error if it cannot create a
2027 * device link from the consumer to a missing supplier.
2030 * 0 on successfully creating a device link
2031 * -EINVAL if the device link cannot be created as expected
2032 * -EAGAIN if the device link cannot be created right now, but it may be
2033 * possible to do that in the future
2035 static int fw_devlink_create_devlink(struct device *con,
2036 struct fwnode_handle *sup_handle,
2037 struct fwnode_link *link)
2039 struct device *sup_dev;
2043 if (con->fwnode == link->consumer)
2044 flags = fw_devlink_get_flags(link->flags);
2046 flags = FW_DEVLINK_FLAGS_PERMISSIVE;
2049 * In some cases, a device P might also be a supplier to its child node
2050 * C. However, this would defer the probe of C until the probe of P
2051 * completes successfully. This is perfectly fine in the device driver
2052 * model. device_add() doesn't guarantee probe completion of the device
2053 * by the time it returns.
2055 * However, there are a few drivers that assume C will finish probing
2056 * as soon as it's added and before P finishes probing. So, we provide
2057 * a flag to let fw_devlink know not to delay the probe of C until the
2058 * probe of P completes successfully.
2060 * When such a flag is set, we can't create device links where P is the
2061 * supplier of C as that would delay the probe of C.
2063 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
2064 fwnode_is_ancestor_of(sup_handle, con->fwnode))
2068 * SYNC_STATE_ONLY device links don't block probing and supports cycles.
2069 * So, one might expect that cycle detection isn't necessary for them.
2070 * However, if the device link was marked as SYNC_STATE_ONLY because
2071 * it's part of a cycle, then we still need to do cycle detection. This
2072 * is because the consumer and supplier might be part of multiple cycles
2073 * and we need to detect all those cycles.
2075 if (!device_link_flag_is_sync_state_only(flags) ||
2076 flags & DL_FLAG_CYCLE) {
2077 device_links_write_lock();
2078 if (__fw_devlink_relax_cycles(con, sup_handle)) {
2079 __fwnode_link_cycle(link);
2080 flags = fw_devlink_get_flags(link->flags);
2081 pr_debug("----- cycle: end -----\n");
2082 dev_info(con, "Fixed dependency cycle(s) with %pfwf\n",
2085 device_links_write_unlock();
2088 if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE)
2089 sup_dev = fwnode_get_next_parent_dev(sup_handle);
2091 sup_dev = get_dev_from_fwnode(sup_handle);
2095 * If it's one of those drivers that don't actually bind to
2096 * their device using driver core, then don't wait on this
2097 * supplier device indefinitely.
2099 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
2100 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
2102 "Not linking %pfwf - dev might never probe\n",
2108 if (con != sup_dev && !device_link_add(con, sup_dev, flags)) {
2109 dev_err(con, "Failed to create device link (0x%x) with %s\n",
2110 flags, dev_name(sup_dev));
2118 * Supplier or supplier's ancestor already initialized without a struct
2119 * device or being probed by a driver.
2121 if (fwnode_init_without_drv(sup_handle) ||
2122 fwnode_ancestor_init_without_drv(sup_handle)) {
2123 dev_dbg(con, "Not linking %pfwf - might never become dev\n",
2130 put_device(sup_dev);
2135 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
2136 * @dev: Device that needs to be linked to its consumers
2138 * This function looks at all the consumer fwnodes of @dev and creates device
2139 * links between the consumer device and @dev (supplier).
2141 * If the consumer device has not been added yet, then this function creates a
2142 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
2143 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
2144 * sync_state() callback before the real consumer device gets to be added and
2147 * Once device links are created from the real consumer to @dev (supplier), the
2148 * fwnode links are deleted.
2150 static void __fw_devlink_link_to_consumers(struct device *dev)
2152 struct fwnode_handle *fwnode = dev->fwnode;
2153 struct fwnode_link *link, *tmp;
2155 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
2156 struct device *con_dev;
2157 bool own_link = true;
2160 con_dev = get_dev_from_fwnode(link->consumer);
2162 * If consumer device is not available yet, make a "proxy"
2163 * SYNC_STATE_ONLY link from the consumer's parent device to
2164 * the supplier device. This is necessary to make sure the
2165 * supplier doesn't get a sync_state() callback before the real
2166 * consumer can create a device link to the supplier.
2168 * This proxy link step is needed to handle the case where the
2169 * consumer's parent device is added before the supplier.
2172 con_dev = fwnode_get_next_parent_dev(link->consumer);
2174 * However, if the consumer's parent device is also the
2175 * parent of the supplier, don't create a
2176 * consumer-supplier link from the parent to its child
2177 * device. Such a dependency is impossible.
2180 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
2181 put_device(con_dev);
2191 ret = fw_devlink_create_devlink(con_dev, fwnode, link);
2192 put_device(con_dev);
2193 if (!own_link || ret == -EAGAIN)
2196 __fwnode_link_del(link);
2201 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
2202 * @dev: The consumer device that needs to be linked to its suppliers
2203 * @fwnode: Root of the fwnode tree that is used to create device links
2205 * This function looks at all the supplier fwnodes of fwnode tree rooted at
2206 * @fwnode and creates device links between @dev (consumer) and all the
2207 * supplier devices of the entire fwnode tree at @fwnode.
2209 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
2210 * and the real suppliers of @dev. Once these device links are created, the
2211 * fwnode links are deleted.
2213 * In addition, it also looks at all the suppliers of the entire fwnode tree
2214 * because some of the child devices of @dev that have not been added yet
2215 * (because @dev hasn't probed) might already have their suppliers added to
2216 * driver core. So, this function creates SYNC_STATE_ONLY device links between
2217 * @dev (consumer) and these suppliers to make sure they don't execute their
2218 * sync_state() callbacks before these child devices have a chance to create
2219 * their device links. The fwnode links that correspond to the child devices
2220 * aren't delete because they are needed later to create the device links
2221 * between the real consumer and supplier devices.
2223 static void __fw_devlink_link_to_suppliers(struct device *dev,
2224 struct fwnode_handle *fwnode)
2226 bool own_link = (dev->fwnode == fwnode);
2227 struct fwnode_link *link, *tmp;
2228 struct fwnode_handle *child = NULL;
2230 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
2232 struct fwnode_handle *sup = link->supplier;
2234 ret = fw_devlink_create_devlink(dev, sup, link);
2235 if (!own_link || ret == -EAGAIN)
2238 __fwnode_link_del(link);
2242 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
2243 * all the descendants. This proxy link step is needed to handle the
2244 * case where the supplier is added before the consumer's parent device
2247 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
2248 __fw_devlink_link_to_suppliers(dev, child);
2251 static void fw_devlink_link_device(struct device *dev)
2253 struct fwnode_handle *fwnode = dev->fwnode;
2255 if (!fw_devlink_flags)
2258 fw_devlink_parse_fwtree(fwnode);
2260 mutex_lock(&fwnode_link_lock);
2261 __fw_devlink_link_to_consumers(dev);
2262 __fw_devlink_link_to_suppliers(dev, fwnode);
2263 mutex_unlock(&fwnode_link_lock);
2266 /* Device links support end. */
2268 int (*platform_notify)(struct device *dev) = NULL;
2269 int (*platform_notify_remove)(struct device *dev) = NULL;
2270 static struct kobject *dev_kobj;
2273 static struct kobject *sysfs_dev_char_kobj;
2275 /* /sys/dev/block */
2276 static struct kobject *sysfs_dev_block_kobj;
2278 static DEFINE_MUTEX(device_hotplug_lock);
2280 void lock_device_hotplug(void)
2282 mutex_lock(&device_hotplug_lock);
2285 void unlock_device_hotplug(void)
2287 mutex_unlock(&device_hotplug_lock);
2290 int lock_device_hotplug_sysfs(void)
2292 if (mutex_trylock(&device_hotplug_lock))
2295 /* Avoid busy looping (5 ms of sleep should do). */
2297 return restart_syscall();
2301 static inline int device_is_not_partition(struct device *dev)
2303 return !(dev->type == &part_type);
2306 static inline int device_is_not_partition(struct device *dev)
2312 static void device_platform_notify(struct device *dev)
2314 acpi_device_notify(dev);
2316 software_node_notify(dev);
2318 if (platform_notify)
2319 platform_notify(dev);
2322 static void device_platform_notify_remove(struct device *dev)
2324 if (platform_notify_remove)
2325 platform_notify_remove(dev);
2327 software_node_notify_remove(dev);
2329 acpi_device_notify_remove(dev);
2333 * dev_driver_string - Return a device's driver name, if at all possible
2334 * @dev: struct device to get the name of
2336 * Will return the device's driver's name if it is bound to a device. If
2337 * the device is not bound to a driver, it will return the name of the bus
2338 * it is attached to. If it is not attached to a bus either, an empty
2339 * string will be returned.
2341 const char *dev_driver_string(const struct device *dev)
2343 struct device_driver *drv;
2345 /* dev->driver can change to NULL underneath us because of unbinding,
2346 * so be careful about accessing it. dev->bus and dev->class should
2347 * never change once they are set, so they don't need special care.
2349 drv = READ_ONCE(dev->driver);
2350 return drv ? drv->name : dev_bus_name(dev);
2352 EXPORT_SYMBOL(dev_driver_string);
2354 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2356 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2359 struct device_attribute *dev_attr = to_dev_attr(attr);
2360 struct device *dev = kobj_to_dev(kobj);
2364 ret = dev_attr->show(dev, dev_attr, buf);
2365 if (ret >= (ssize_t)PAGE_SIZE) {
2366 printk("dev_attr_show: %pS returned bad count\n",
2372 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2373 const char *buf, size_t count)
2375 struct device_attribute *dev_attr = to_dev_attr(attr);
2376 struct device *dev = kobj_to_dev(kobj);
2379 if (dev_attr->store)
2380 ret = dev_attr->store(dev, dev_attr, buf, count);
2384 static const struct sysfs_ops dev_sysfs_ops = {
2385 .show = dev_attr_show,
2386 .store = dev_attr_store,
2389 #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2391 ssize_t device_store_ulong(struct device *dev,
2392 struct device_attribute *attr,
2393 const char *buf, size_t size)
2395 struct dev_ext_attribute *ea = to_ext_attr(attr);
2399 ret = kstrtoul(buf, 0, &new);
2402 *(unsigned long *)(ea->var) = new;
2403 /* Always return full write size even if we didn't consume all */
2406 EXPORT_SYMBOL_GPL(device_store_ulong);
2408 ssize_t device_show_ulong(struct device *dev,
2409 struct device_attribute *attr,
2412 struct dev_ext_attribute *ea = to_ext_attr(attr);
2413 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2415 EXPORT_SYMBOL_GPL(device_show_ulong);
2417 ssize_t device_store_int(struct device *dev,
2418 struct device_attribute *attr,
2419 const char *buf, size_t size)
2421 struct dev_ext_attribute *ea = to_ext_attr(attr);
2425 ret = kstrtol(buf, 0, &new);
2429 if (new > INT_MAX || new < INT_MIN)
2431 *(int *)(ea->var) = new;
2432 /* Always return full write size even if we didn't consume all */
2435 EXPORT_SYMBOL_GPL(device_store_int);
2437 ssize_t device_show_int(struct device *dev,
2438 struct device_attribute *attr,
2441 struct dev_ext_attribute *ea = to_ext_attr(attr);
2443 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2445 EXPORT_SYMBOL_GPL(device_show_int);
2447 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2448 const char *buf, size_t size)
2450 struct dev_ext_attribute *ea = to_ext_attr(attr);
2452 if (kstrtobool(buf, ea->var) < 0)
2457 EXPORT_SYMBOL_GPL(device_store_bool);
2459 ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2462 struct dev_ext_attribute *ea = to_ext_attr(attr);
2464 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2466 EXPORT_SYMBOL_GPL(device_show_bool);
2469 * device_release - free device structure.
2470 * @kobj: device's kobject.
2472 * This is called once the reference count for the object
2473 * reaches 0. We forward the call to the device's release
2474 * method, which should handle actually freeing the structure.
2476 static void device_release(struct kobject *kobj)
2478 struct device *dev = kobj_to_dev(kobj);
2479 struct device_private *p = dev->p;
2482 * Some platform devices are driven without driver attached
2483 * and managed resources may have been acquired. Make sure
2484 * all resources are released.
2486 * Drivers still can add resources into device after device
2487 * is deleted but alive, so release devres here to avoid
2488 * possible memory leak.
2490 devres_release_all(dev);
2492 kfree(dev->dma_range_map);
2496 else if (dev->type && dev->type->release)
2497 dev->type->release(dev);
2498 else if (dev->class && dev->class->dev_release)
2499 dev->class->dev_release(dev);
2501 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",
2506 static const void *device_namespace(const struct kobject *kobj)
2508 const struct device *dev = kobj_to_dev(kobj);
2509 const void *ns = NULL;
2511 if (dev->class && dev->class->ns_type)
2512 ns = dev->class->namespace(dev);
2517 static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2519 const struct device *dev = kobj_to_dev(kobj);
2521 if (dev->class && dev->class->get_ownership)
2522 dev->class->get_ownership(dev, uid, gid);
2525 static const struct kobj_type device_ktype = {
2526 .release = device_release,
2527 .sysfs_ops = &dev_sysfs_ops,
2528 .namespace = device_namespace,
2529 .get_ownership = device_get_ownership,
2533 static int dev_uevent_filter(const struct kobject *kobj)
2535 const struct kobj_type *ktype = get_ktype(kobj);
2537 if (ktype == &device_ktype) {
2538 const struct device *dev = kobj_to_dev(kobj);
2547 static const char *dev_uevent_name(const struct kobject *kobj)
2549 const struct device *dev = kobj_to_dev(kobj);
2552 return dev->bus->name;
2554 return dev->class->name;
2558 static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
2560 const struct device *dev = kobj_to_dev(kobj);
2563 /* add device node properties if present */
2564 if (MAJOR(dev->devt)) {
2568 kuid_t uid = GLOBAL_ROOT_UID;
2569 kgid_t gid = GLOBAL_ROOT_GID;
2571 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2572 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2573 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2575 add_uevent_var(env, "DEVNAME=%s", name);
2577 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2578 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2579 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2580 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2581 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2586 if (dev->type && dev->type->name)
2587 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2590 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2592 /* Add common DT information about the device */
2593 of_device_uevent(dev, env);
2595 /* have the bus specific function add its stuff */
2596 if (dev->bus && dev->bus->uevent) {
2597 retval = dev->bus->uevent(dev, env);
2599 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2600 dev_name(dev), __func__, retval);
2603 /* have the class specific function add its stuff */
2604 if (dev->class && dev->class->dev_uevent) {
2605 retval = dev->class->dev_uevent(dev, env);
2607 pr_debug("device: '%s': %s: class uevent() "
2608 "returned %d\n", dev_name(dev),
2612 /* have the device type specific function add its stuff */
2613 if (dev->type && dev->type->uevent) {
2614 retval = dev->type->uevent(dev, env);
2616 pr_debug("device: '%s': %s: dev_type uevent() "
2617 "returned %d\n", dev_name(dev),
2624 static const struct kset_uevent_ops device_uevent_ops = {
2625 .filter = dev_uevent_filter,
2626 .name = dev_uevent_name,
2627 .uevent = dev_uevent,
2630 static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2633 struct kobject *top_kobj;
2635 struct kobj_uevent_env *env = NULL;
2640 /* search the kset, the device belongs to */
2641 top_kobj = &dev->kobj;
2642 while (!top_kobj->kset && top_kobj->parent)
2643 top_kobj = top_kobj->parent;
2644 if (!top_kobj->kset)
2647 kset = top_kobj->kset;
2648 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2651 /* respect filter */
2652 if (kset->uevent_ops && kset->uevent_ops->filter)
2653 if (!kset->uevent_ops->filter(&dev->kobj))
2656 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2660 /* let the kset specific function add its keys */
2661 retval = kset->uevent_ops->uevent(&dev->kobj, env);
2665 /* copy keys to file */
2666 for (i = 0; i < env->envp_idx; i++)
2667 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2673 static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2674 const char *buf, size_t count)
2678 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2681 dev_err(dev, "uevent: failed to send synthetic uevent: %d\n", rc);
2687 static DEVICE_ATTR_RW(uevent);
2689 static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2695 val = !dev->offline;
2697 return sysfs_emit(buf, "%u\n", val);
2700 static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2701 const char *buf, size_t count)
2706 ret = kstrtobool(buf, &val);
2710 ret = lock_device_hotplug_sysfs();
2714 ret = val ? device_online(dev) : device_offline(dev);
2715 unlock_device_hotplug();
2716 return ret < 0 ? ret : count;
2718 static DEVICE_ATTR_RW(online);
2720 static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2725 switch (dev->removable) {
2726 case DEVICE_REMOVABLE:
2735 return sysfs_emit(buf, "%s\n", loc);
2737 static DEVICE_ATTR_RO(removable);
2739 int device_add_groups(struct device *dev, const struct attribute_group **groups)
2741 return sysfs_create_groups(&dev->kobj, groups);
2743 EXPORT_SYMBOL_GPL(device_add_groups);
2745 void device_remove_groups(struct device *dev,
2746 const struct attribute_group **groups)
2748 sysfs_remove_groups(&dev->kobj, groups);
2750 EXPORT_SYMBOL_GPL(device_remove_groups);
2752 union device_attr_group_devres {
2753 const struct attribute_group *group;
2754 const struct attribute_group **groups;
2757 static void devm_attr_group_remove(struct device *dev, void *res)
2759 union device_attr_group_devres *devres = res;
2760 const struct attribute_group *group = devres->group;
2762 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2763 sysfs_remove_group(&dev->kobj, group);
2766 static void devm_attr_groups_remove(struct device *dev, void *res)
2768 union device_attr_group_devres *devres = res;
2769 const struct attribute_group **groups = devres->groups;
2771 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2772 sysfs_remove_groups(&dev->kobj, groups);
2776 * devm_device_add_group - given a device, create a managed attribute group
2777 * @dev: The device to create the group for
2778 * @grp: The attribute group to create
2780 * This function creates a group for the first time. It will explicitly
2781 * warn and error if any of the attribute files being created already exist.
2783 * Returns 0 on success or error code on failure.
2785 int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2787 union device_attr_group_devres *devres;
2790 devres = devres_alloc(devm_attr_group_remove,
2791 sizeof(*devres), GFP_KERNEL);
2795 error = sysfs_create_group(&dev->kobj, grp);
2797 devres_free(devres);
2801 devres->group = grp;
2802 devres_add(dev, devres);
2805 EXPORT_SYMBOL_GPL(devm_device_add_group);
2808 * devm_device_add_groups - create a bunch of managed attribute groups
2809 * @dev: The device to create the group for
2810 * @groups: The attribute groups to create, NULL terminated
2812 * This function creates a bunch of managed attribute groups. If an error
2813 * occurs when creating a group, all previously created groups will be
2814 * removed, unwinding everything back to the original state when this
2815 * function was called. It will explicitly warn and error if any of the
2816 * attribute files being created already exist.
2818 * Returns 0 on success or error code from sysfs_create_group on failure.
2820 int devm_device_add_groups(struct device *dev,
2821 const struct attribute_group **groups)
2823 union device_attr_group_devres *devres;
2826 devres = devres_alloc(devm_attr_groups_remove,
2827 sizeof(*devres), GFP_KERNEL);
2831 error = sysfs_create_groups(&dev->kobj, groups);
2833 devres_free(devres);
2837 devres->groups = groups;
2838 devres_add(dev, devres);
2841 EXPORT_SYMBOL_GPL(devm_device_add_groups);
2843 static int device_add_attrs(struct device *dev)
2845 const struct class *class = dev->class;
2846 const struct device_type *type = dev->type;
2850 error = device_add_groups(dev, class->dev_groups);
2856 error = device_add_groups(dev, type->groups);
2858 goto err_remove_class_groups;
2861 error = device_add_groups(dev, dev->groups);
2863 goto err_remove_type_groups;
2865 if (device_supports_offline(dev) && !dev->offline_disabled) {
2866 error = device_create_file(dev, &dev_attr_online);
2868 goto err_remove_dev_groups;
2871 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2872 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2874 goto err_remove_dev_online;
2877 if (dev_removable_is_valid(dev)) {
2878 error = device_create_file(dev, &dev_attr_removable);
2880 goto err_remove_dev_waiting_for_supplier;
2883 if (dev_add_physical_location(dev)) {
2884 error = device_add_group(dev,
2885 &dev_attr_physical_location_group);
2887 goto err_remove_dev_removable;
2892 err_remove_dev_removable:
2893 device_remove_file(dev, &dev_attr_removable);
2894 err_remove_dev_waiting_for_supplier:
2895 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2896 err_remove_dev_online:
2897 device_remove_file(dev, &dev_attr_online);
2898 err_remove_dev_groups:
2899 device_remove_groups(dev, dev->groups);
2900 err_remove_type_groups:
2902 device_remove_groups(dev, type->groups);
2903 err_remove_class_groups:
2905 device_remove_groups(dev, class->dev_groups);
2910 static void device_remove_attrs(struct device *dev)
2912 const struct class *class = dev->class;
2913 const struct device_type *type = dev->type;
2915 if (dev->physical_location) {
2916 device_remove_group(dev, &dev_attr_physical_location_group);
2917 kfree(dev->physical_location);
2920 device_remove_file(dev, &dev_attr_removable);
2921 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2922 device_remove_file(dev, &dev_attr_online);
2923 device_remove_groups(dev, dev->groups);
2926 device_remove_groups(dev, type->groups);
2929 device_remove_groups(dev, class->dev_groups);
2932 static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2935 return print_dev_t(buf, dev->devt);
2937 static DEVICE_ATTR_RO(dev);
2940 struct kset *devices_kset;
2943 * devices_kset_move_before - Move device in the devices_kset's list.
2944 * @deva: Device to move.
2945 * @devb: Device @deva should come before.
2947 static void devices_kset_move_before(struct device *deva, struct device *devb)
2951 pr_debug("devices_kset: Moving %s before %s\n",
2952 dev_name(deva), dev_name(devb));
2953 spin_lock(&devices_kset->list_lock);
2954 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2955 spin_unlock(&devices_kset->list_lock);
2959 * devices_kset_move_after - Move device in the devices_kset's list.
2960 * @deva: Device to move
2961 * @devb: Device @deva should come after.
2963 static void devices_kset_move_after(struct device *deva, struct device *devb)
2967 pr_debug("devices_kset: Moving %s after %s\n",
2968 dev_name(deva), dev_name(devb));
2969 spin_lock(&devices_kset->list_lock);
2970 list_move(&deva->kobj.entry, &devb->kobj.entry);
2971 spin_unlock(&devices_kset->list_lock);
2975 * devices_kset_move_last - move the device to the end of devices_kset's list.
2976 * @dev: device to move
2978 void devices_kset_move_last(struct device *dev)
2982 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2983 spin_lock(&devices_kset->list_lock);
2984 list_move_tail(&dev->kobj.entry, &devices_kset->list);
2985 spin_unlock(&devices_kset->list_lock);
2989 * device_create_file - create sysfs attribute file for device.
2991 * @attr: device attribute descriptor.
2993 int device_create_file(struct device *dev,
2994 const struct device_attribute *attr)
2999 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
3000 "Attribute %s: write permission without 'store'\n",
3002 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
3003 "Attribute %s: read permission without 'show'\n",
3005 error = sysfs_create_file(&dev->kobj, &attr->attr);
3010 EXPORT_SYMBOL_GPL(device_create_file);
3013 * device_remove_file - remove sysfs attribute file.
3015 * @attr: device attribute descriptor.
3017 void device_remove_file(struct device *dev,
3018 const struct device_attribute *attr)
3021 sysfs_remove_file(&dev->kobj, &attr->attr);
3023 EXPORT_SYMBOL_GPL(device_remove_file);
3026 * device_remove_file_self - remove sysfs attribute file from its own method.
3028 * @attr: device attribute descriptor.
3030 * See kernfs_remove_self() for details.
3032 bool device_remove_file_self(struct device *dev,
3033 const struct device_attribute *attr)
3036 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
3040 EXPORT_SYMBOL_GPL(device_remove_file_self);
3043 * device_create_bin_file - create sysfs binary attribute file for device.
3045 * @attr: device binary attribute descriptor.
3047 int device_create_bin_file(struct device *dev,
3048 const struct bin_attribute *attr)
3050 int error = -EINVAL;
3052 error = sysfs_create_bin_file(&dev->kobj, attr);
3055 EXPORT_SYMBOL_GPL(device_create_bin_file);
3058 * device_remove_bin_file - remove sysfs binary attribute file
3060 * @attr: device binary attribute descriptor.
3062 void device_remove_bin_file(struct device *dev,
3063 const struct bin_attribute *attr)
3066 sysfs_remove_bin_file(&dev->kobj, attr);
3068 EXPORT_SYMBOL_GPL(device_remove_bin_file);
3070 static void klist_children_get(struct klist_node *n)
3072 struct device_private *p = to_device_private_parent(n);
3073 struct device *dev = p->device;
3078 static void klist_children_put(struct klist_node *n)
3080 struct device_private *p = to_device_private_parent(n);
3081 struct device *dev = p->device;
3087 * device_initialize - init device structure.
3090 * This prepares the device for use by other layers by initializing
3092 * It is the first half of device_register(), if called by
3093 * that function, though it can also be called separately, so one
3094 * may use @dev's fields. In particular, get_device()/put_device()
3095 * may be used for reference counting of @dev after calling this
3098 * All fields in @dev must be initialized by the caller to 0, except
3099 * for those explicitly set to some other value. The simplest
3100 * approach is to use kzalloc() to allocate the structure containing
3103 * NOTE: Use put_device() to give up your reference instead of freeing
3104 * @dev directly once you have called this function.
3106 void device_initialize(struct device *dev)
3108 dev->kobj.kset = devices_kset;
3109 kobject_init(&dev->kobj, &device_ktype);
3110 INIT_LIST_HEAD(&dev->dma_pools);
3111 mutex_init(&dev->mutex);
3112 lockdep_set_novalidate_class(&dev->mutex);
3113 spin_lock_init(&dev->devres_lock);
3114 INIT_LIST_HEAD(&dev->devres_head);
3115 device_pm_init(dev);
3116 set_dev_node(dev, NUMA_NO_NODE);
3117 INIT_LIST_HEAD(&dev->links.consumers);
3118 INIT_LIST_HEAD(&dev->links.suppliers);
3119 INIT_LIST_HEAD(&dev->links.defer_sync);
3120 dev->links.status = DL_DEV_NO_DRIVER;
3121 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
3122 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
3123 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
3124 dev->dma_coherent = dma_default_coherent;
3126 swiotlb_dev_init(dev);
3128 EXPORT_SYMBOL_GPL(device_initialize);
3130 struct kobject *virtual_device_parent(struct device *dev)
3132 static struct kobject *virtual_dir = NULL;
3135 virtual_dir = kobject_create_and_add("virtual",
3136 &devices_kset->kobj);
3142 struct kobject kobj;
3143 const struct class *class;
3146 #define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
3148 static void class_dir_release(struct kobject *kobj)
3150 struct class_dir *dir = to_class_dir(kobj);
3155 struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *kobj)
3157 const struct class_dir *dir = to_class_dir(kobj);
3158 return dir->class->ns_type;
3161 static const struct kobj_type class_dir_ktype = {
3162 .release = class_dir_release,
3163 .sysfs_ops = &kobj_sysfs_ops,
3164 .child_ns_type = class_dir_child_ns_type
3167 static struct kobject *class_dir_create_and_add(struct subsys_private *sp,
3168 struct kobject *parent_kobj)
3170 struct class_dir *dir;
3173 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
3175 return ERR_PTR(-ENOMEM);
3177 dir->class = sp->class;
3178 kobject_init(&dir->kobj, &class_dir_ktype);
3180 dir->kobj.kset = &sp->glue_dirs;
3182 retval = kobject_add(&dir->kobj, parent_kobj, "%s", sp->class->name);
3184 kobject_put(&dir->kobj);
3185 return ERR_PTR(retval);
3190 static DEFINE_MUTEX(gdp_mutex);
3192 static struct kobject *get_device_parent(struct device *dev,
3193 struct device *parent)
3195 struct subsys_private *sp = class_to_subsys(dev->class);
3196 struct kobject *kobj = NULL;
3199 struct kobject *parent_kobj;
3203 * If we have no parent, we live in "virtual".
3204 * Class-devices with a non class-device as parent, live
3205 * in a "glue" directory to prevent namespace collisions.
3208 parent_kobj = virtual_device_parent(dev);
3209 else if (parent->class && !dev->class->ns_type) {
3211 return &parent->kobj;
3213 parent_kobj = &parent->kobj;
3216 mutex_lock(&gdp_mutex);
3218 /* find our class-directory at the parent and reference it */
3219 spin_lock(&sp->glue_dirs.list_lock);
3220 list_for_each_entry(k, &sp->glue_dirs.list, entry)
3221 if (k->parent == parent_kobj) {
3222 kobj = kobject_get(k);
3225 spin_unlock(&sp->glue_dirs.list_lock);
3227 mutex_unlock(&gdp_mutex);
3232 /* or create a new class-directory at the parent device */
3233 k = class_dir_create_and_add(sp, parent_kobj);
3234 /* do not emit an uevent for this simple "glue" directory */
3235 mutex_unlock(&gdp_mutex);
3240 /* subsystems can specify a default root directory for their devices */
3241 if (!parent && dev->bus) {
3242 struct device *dev_root = bus_get_dev_root(dev->bus);
3245 kobj = &dev_root->kobj;
3246 put_device(dev_root);
3252 return &parent->kobj;
3256 static inline bool live_in_glue_dir(struct kobject *kobj,
3259 struct subsys_private *sp;
3262 if (!kobj || !dev->class)
3265 sp = class_to_subsys(dev->class);
3269 if (kobj->kset == &sp->glue_dirs)
3278 static inline struct kobject *get_glue_dir(struct device *dev)
3280 return dev->kobj.parent;
3284 * kobject_has_children - Returns whether a kobject has children.
3285 * @kobj: the object to test
3287 * This will return whether a kobject has other kobjects as children.
3289 * It does NOT account for the presence of attribute files, only sub
3290 * directories. It also assumes there is no concurrent addition or
3291 * removal of such children, and thus relies on external locking.
3293 static inline bool kobject_has_children(struct kobject *kobj)
3295 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
3297 return kobj->sd && kobj->sd->dir.subdirs;
3301 * make sure cleaning up dir as the last step, we need to make
3302 * sure .release handler of kobject is run with holding the
3305 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3309 /* see if we live in a "glue" directory */
3310 if (!live_in_glue_dir(glue_dir, dev))
3313 mutex_lock(&gdp_mutex);
3315 * There is a race condition between removing glue directory
3316 * and adding a new device under the glue directory.
3321 * get_device_parent()
3322 * class_dir_create_and_add()
3323 * kobject_add_internal()
3324 * create_dir() // create glue_dir
3327 * get_device_parent()
3328 * kobject_get() // get glue_dir
3331 * cleanup_glue_dir()
3332 * kobject_del(glue_dir)
3335 * kobject_add_internal()
3336 * create_dir() // in glue_dir
3337 * sysfs_create_dir_ns()
3338 * kernfs_create_dir_ns(sd)
3340 * sysfs_remove_dir() // glue_dir->sd=NULL
3341 * sysfs_put() // free glue_dir->sd
3344 * kernfs_new_node(sd)
3345 * kernfs_get(glue_dir)
3349 * Before CPU1 remove last child device under glue dir, if CPU2 add
3350 * a new device under glue dir, the glue_dir kobject reference count
3351 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3352 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3353 * and sysfs_put(). This result in glue_dir->sd is freed.
3355 * Then the CPU2 will see a stale "empty" but still potentially used
3356 * glue dir around in kernfs_new_node().
3358 * In order to avoid this happening, we also should make sure that
3359 * kernfs_node for glue_dir is released in CPU1 only when refcount
3360 * for glue_dir kobj is 1.
3362 ref = kref_read(&glue_dir->kref);
3363 if (!kobject_has_children(glue_dir) && !--ref)
3364 kobject_del(glue_dir);
3365 kobject_put(glue_dir);
3366 mutex_unlock(&gdp_mutex);
3369 static int device_add_class_symlinks(struct device *dev)
3371 struct device_node *of_node = dev_of_node(dev);
3372 struct subsys_private *sp;
3376 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3378 dev_warn(dev, "Error %d creating of_node link\n",error);
3379 /* An error here doesn't warrant bringing down the device */
3382 sp = class_to_subsys(dev->class);
3386 error = sysfs_create_link(&dev->kobj, &sp->subsys.kobj, "subsystem");
3390 if (dev->parent && device_is_not_partition(dev)) {
3391 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3397 /* link in the class directory pointing to the device */
3398 error = sysfs_create_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3404 sysfs_remove_link(&dev->kobj, "device");
3406 sysfs_remove_link(&dev->kobj, "subsystem");
3408 sysfs_remove_link(&dev->kobj, "of_node");
3414 static void device_remove_class_symlinks(struct device *dev)
3416 struct subsys_private *sp = class_to_subsys(dev->class);
3418 if (dev_of_node(dev))
3419 sysfs_remove_link(&dev->kobj, "of_node");
3424 if (dev->parent && device_is_not_partition(dev))
3425 sysfs_remove_link(&dev->kobj, "device");
3426 sysfs_remove_link(&dev->kobj, "subsystem");
3427 sysfs_delete_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3432 * dev_set_name - set a device name
3434 * @fmt: format string for the device's name
3436 int dev_set_name(struct device *dev, const char *fmt, ...)
3441 va_start(vargs, fmt);
3442 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3446 EXPORT_SYMBOL_GPL(dev_set_name);
3448 /* select a /sys/dev/ directory for the device */
3449 static struct kobject *device_to_dev_kobj(struct device *dev)
3451 if (is_blockdev(dev))
3452 return sysfs_dev_block_kobj;
3454 return sysfs_dev_char_kobj;
3457 static int device_create_sys_dev_entry(struct device *dev)
3459 struct kobject *kobj = device_to_dev_kobj(dev);
3464 format_dev_t(devt_str, dev->devt);
3465 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3471 static void device_remove_sys_dev_entry(struct device *dev)
3473 struct kobject *kobj = device_to_dev_kobj(dev);
3477 format_dev_t(devt_str, dev->devt);
3478 sysfs_remove_link(kobj, devt_str);
3482 static int device_private_init(struct device *dev)
3484 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3487 dev->p->device = dev;
3488 klist_init(&dev->p->klist_children, klist_children_get,
3489 klist_children_put);
3490 INIT_LIST_HEAD(&dev->p->deferred_probe);
3495 * device_add - add device to device hierarchy.
3498 * This is part 2 of device_register(), though may be called
3499 * separately _iff_ device_initialize() has been called separately.
3501 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3502 * to the global and sibling lists for the device, then
3503 * adds it to the other relevant subsystems of the driver model.
3505 * Do not call this routine or device_register() more than once for
3506 * any device structure. The driver model core is not designed to work
3507 * with devices that get unregistered and then spring back to life.
3508 * (Among other things, it's very hard to guarantee that all references
3509 * to the previous incarnation of @dev have been dropped.) Allocate
3510 * and register a fresh new struct device instead.
3512 * NOTE: _Never_ directly free @dev after calling this function, even
3513 * if it returned an error! Always use put_device() to give up your
3514 * reference instead.
3516 * Rule of thumb is: if device_add() succeeds, you should call
3517 * device_del() when you want to get rid of it. If device_add() has
3518 * *not* succeeded, use *only* put_device() to drop the reference
3521 int device_add(struct device *dev)
3523 struct subsys_private *sp;
3524 struct device *parent;
3525 struct kobject *kobj;
3526 struct class_interface *class_intf;
3527 int error = -EINVAL;
3528 struct kobject *glue_dir = NULL;
3530 dev = get_device(dev);
3535 error = device_private_init(dev);
3541 * for statically allocated devices, which should all be converted
3542 * some day, we need to initialize the name. We prevent reading back
3543 * the name, and force the use of dev_name()
3545 if (dev->init_name) {
3546 error = dev_set_name(dev, "%s", dev->init_name);
3547 dev->init_name = NULL;
3552 /* subsystems can specify simple device enumeration */
3553 else if (dev->bus && dev->bus->dev_name)
3554 error = dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3560 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3562 parent = get_device(dev->parent);
3563 kobj = get_device_parent(dev, parent);
3565 error = PTR_ERR(kobj);
3569 dev->kobj.parent = kobj;
3571 /* use parent numa_node */
3572 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3573 set_dev_node(dev, dev_to_node(parent));
3575 /* first, register with generic layer. */
3576 /* we require the name to be set before, and pass NULL */
3577 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3583 /* notify platform of device entry */
3584 device_platform_notify(dev);
3586 error = device_create_file(dev, &dev_attr_uevent);
3590 error = device_add_class_symlinks(dev);
3593 error = device_add_attrs(dev);
3596 error = bus_add_device(dev);
3599 error = dpm_sysfs_add(dev);
3604 if (MAJOR(dev->devt)) {
3605 error = device_create_file(dev, &dev_attr_dev);
3609 error = device_create_sys_dev_entry(dev);
3613 devtmpfs_create_node(dev);
3616 /* Notify clients of device addition. This call must come
3617 * after dpm_sysfs_add() and before kobject_uevent().
3619 bus_notify(dev, BUS_NOTIFY_ADD_DEVICE);
3620 kobject_uevent(&dev->kobj, KOBJ_ADD);
3623 * Check if any of the other devices (consumers) have been waiting for
3624 * this device (supplier) to be added so that they can create a device
3627 * This needs to happen after device_pm_add() because device_link_add()
3628 * requires the supplier be registered before it's called.
3630 * But this also needs to happen before bus_probe_device() to make sure
3631 * waiting consumers can link to it before the driver is bound to the
3632 * device and the driver sync_state callback is called for this device.
3634 if (dev->fwnode && !dev->fwnode->dev) {
3635 dev->fwnode->dev = dev;
3636 fw_devlink_link_device(dev);
3639 bus_probe_device(dev);
3642 * If all driver registration is done and a newly added device doesn't
3643 * match with any driver, don't block its consumers from probing in
3644 * case the consumer device is able to operate without this supplier.
3646 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3647 fw_devlink_unblock_consumers(dev);
3650 klist_add_tail(&dev->p->knode_parent,
3651 &parent->p->klist_children);
3653 sp = class_to_subsys(dev->class);
3655 mutex_lock(&sp->mutex);
3656 /* tie the class to the device */
3657 klist_add_tail(&dev->p->knode_class, &sp->klist_devices);
3659 /* notify any interfaces that the device is here */
3660 list_for_each_entry(class_intf, &sp->interfaces, node)
3661 if (class_intf->add_dev)
3662 class_intf->add_dev(dev);
3663 mutex_unlock(&sp->mutex);
3670 if (MAJOR(dev->devt))
3671 device_remove_file(dev, &dev_attr_dev);
3673 device_pm_remove(dev);
3674 dpm_sysfs_remove(dev);
3677 bus_remove_device(dev);
3679 device_remove_attrs(dev);
3681 device_remove_class_symlinks(dev);
3683 device_remove_file(dev, &dev_attr_uevent);
3685 device_platform_notify_remove(dev);
3686 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3687 glue_dir = get_glue_dir(dev);
3688 kobject_del(&dev->kobj);
3690 cleanup_glue_dir(dev, glue_dir);
3698 EXPORT_SYMBOL_GPL(device_add);
3701 * device_register - register a device with the system.
3702 * @dev: pointer to the device structure
3704 * This happens in two clean steps - initialize the device
3705 * and add it to the system. The two steps can be called
3706 * separately, but this is the easiest and most common.
3707 * I.e. you should only call the two helpers separately if
3708 * have a clearly defined need to use and refcount the device
3709 * before it is added to the hierarchy.
3711 * For more information, see the kerneldoc for device_initialize()
3714 * NOTE: _Never_ directly free @dev after calling this function, even
3715 * if it returned an error! Always use put_device() to give up the
3716 * reference initialized in this function instead.
3718 int device_register(struct device *dev)
3720 device_initialize(dev);
3721 return device_add(dev);
3723 EXPORT_SYMBOL_GPL(device_register);
3726 * get_device - increment reference count for device.
3729 * This simply forwards the call to kobject_get(), though
3730 * we do take care to provide for the case that we get a NULL
3731 * pointer passed in.
3733 struct device *get_device(struct device *dev)
3735 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3737 EXPORT_SYMBOL_GPL(get_device);
3740 * put_device - decrement reference count.
3741 * @dev: device in question.
3743 void put_device(struct device *dev)
3745 /* might_sleep(); */
3747 kobject_put(&dev->kobj);
3749 EXPORT_SYMBOL_GPL(put_device);
3751 bool kill_device(struct device *dev)
3754 * Require the device lock and set the "dead" flag to guarantee that
3755 * the update behavior is consistent with the other bitfields near
3756 * it and that we cannot have an asynchronous probe routine trying
3757 * to run while we are tearing out the bus/class/sysfs from
3758 * underneath the device.
3760 device_lock_assert(dev);
3764 dev->p->dead = true;
3767 EXPORT_SYMBOL_GPL(kill_device);
3770 * device_del - delete device from system.
3773 * This is the first part of the device unregistration
3774 * sequence. This removes the device from the lists we control
3775 * from here, has it removed from the other driver model
3776 * subsystems it was added to in device_add(), and removes it
3777 * from the kobject hierarchy.
3779 * NOTE: this should be called manually _iff_ device_add() was
3780 * also called manually.
3782 void device_del(struct device *dev)
3784 struct subsys_private *sp;
3785 struct device *parent = dev->parent;
3786 struct kobject *glue_dir = NULL;
3787 struct class_interface *class_intf;
3788 unsigned int noio_flag;
3794 if (dev->fwnode && dev->fwnode->dev == dev)
3795 dev->fwnode->dev = NULL;
3797 /* Notify clients of device removal. This call must come
3798 * before dpm_sysfs_remove().
3800 noio_flag = memalloc_noio_save();
3801 bus_notify(dev, BUS_NOTIFY_DEL_DEVICE);
3803 dpm_sysfs_remove(dev);
3805 klist_del(&dev->p->knode_parent);
3806 if (MAJOR(dev->devt)) {
3807 devtmpfs_delete_node(dev);
3808 device_remove_sys_dev_entry(dev);
3809 device_remove_file(dev, &dev_attr_dev);
3812 sp = class_to_subsys(dev->class);
3814 device_remove_class_symlinks(dev);
3816 mutex_lock(&sp->mutex);
3817 /* notify any interfaces that the device is now gone */
3818 list_for_each_entry(class_intf, &sp->interfaces, node)
3819 if (class_intf->remove_dev)
3820 class_intf->remove_dev(dev);
3821 /* remove the device from the class list */
3822 klist_del(&dev->p->knode_class);
3823 mutex_unlock(&sp->mutex);
3826 device_remove_file(dev, &dev_attr_uevent);
3827 device_remove_attrs(dev);
3828 bus_remove_device(dev);
3829 device_pm_remove(dev);
3830 driver_deferred_probe_del(dev);
3831 device_platform_notify_remove(dev);
3832 device_links_purge(dev);
3835 * If a device does not have a driver attached, we need to clean
3836 * up any managed resources. We do this in device_release(), but
3837 * it's never called (and we leak the device) if a managed
3838 * resource holds a reference to the device. So release all
3839 * managed resources here, like we do in driver_detach(). We
3840 * still need to do so again in device_release() in case someone
3841 * adds a new resource after this point, though.
3843 devres_release_all(dev);
3845 bus_notify(dev, BUS_NOTIFY_REMOVED_DEVICE);
3846 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3847 glue_dir = get_glue_dir(dev);
3848 kobject_del(&dev->kobj);
3849 cleanup_glue_dir(dev, glue_dir);
3850 memalloc_noio_restore(noio_flag);
3853 EXPORT_SYMBOL_GPL(device_del);
3856 * device_unregister - unregister device from system.
3857 * @dev: device going away.
3859 * We do this in two parts, like we do device_register(). First,
3860 * we remove it from all the subsystems with device_del(), then
3861 * we decrement the reference count via put_device(). If that
3862 * is the final reference count, the device will be cleaned up
3863 * via device_release() above. Otherwise, the structure will
3864 * stick around until the final reference to the device is dropped.
3866 void device_unregister(struct device *dev)
3868 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3872 EXPORT_SYMBOL_GPL(device_unregister);
3874 static struct device *prev_device(struct klist_iter *i)
3876 struct klist_node *n = klist_prev(i);
3877 struct device *dev = NULL;
3878 struct device_private *p;
3881 p = to_device_private_parent(n);
3887 static struct device *next_device(struct klist_iter *i)
3889 struct klist_node *n = klist_next(i);
3890 struct device *dev = NULL;
3891 struct device_private *p;
3894 p = to_device_private_parent(n);
3901 * device_get_devnode - path of device node file
3903 * @mode: returned file access mode
3904 * @uid: returned file owner
3905 * @gid: returned file group
3906 * @tmp: possibly allocated string
3908 * Return the relative path of a possible device node.
3909 * Non-default names may need to allocate a memory to compose
3910 * a name. This memory is returned in tmp and needs to be
3911 * freed by the caller.
3913 const char *device_get_devnode(const struct device *dev,
3914 umode_t *mode, kuid_t *uid, kgid_t *gid,
3921 /* the device type may provide a specific name */
3922 if (dev->type && dev->type->devnode)
3923 *tmp = dev->type->devnode(dev, mode, uid, gid);
3927 /* the class may provide a specific name */
3928 if (dev->class && dev->class->devnode)
3929 *tmp = dev->class->devnode(dev, mode);
3933 /* return name without allocation, tmp == NULL */
3934 if (strchr(dev_name(dev), '!') == NULL)
3935 return dev_name(dev);
3937 /* replace '!' in the name with '/' */
3938 s = kstrdup_and_replace(dev_name(dev), '!', '/', GFP_KERNEL);
3945 * device_for_each_child - device child iterator.
3946 * @parent: parent struct device.
3947 * @fn: function to be called for each device.
3948 * @data: data for the callback.
3950 * Iterate over @parent's child devices, and call @fn for each,
3953 * We check the return of @fn each time. If it returns anything
3954 * other than 0, we break out and return that value.
3956 int device_for_each_child(struct device *parent, void *data,
3957 int (*fn)(struct device *dev, void *data))
3959 struct klist_iter i;
3960 struct device *child;
3966 klist_iter_init(&parent->p->klist_children, &i);
3967 while (!error && (child = next_device(&i)))
3968 error = fn(child, data);
3969 klist_iter_exit(&i);
3972 EXPORT_SYMBOL_GPL(device_for_each_child);
3975 * device_for_each_child_reverse - device child iterator in reversed order.
3976 * @parent: parent struct device.
3977 * @fn: function to be called for each device.
3978 * @data: data for the callback.
3980 * Iterate over @parent's child devices, and call @fn for each,
3983 * We check the return of @fn each time. If it returns anything
3984 * other than 0, we break out and return that value.
3986 int device_for_each_child_reverse(struct device *parent, void *data,
3987 int (*fn)(struct device *dev, void *data))
3989 struct klist_iter i;
3990 struct device *child;
3996 klist_iter_init(&parent->p->klist_children, &i);
3997 while ((child = prev_device(&i)) && !error)
3998 error = fn(child, data);
3999 klist_iter_exit(&i);
4002 EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
4005 * device_find_child - device iterator for locating a particular device.
4006 * @parent: parent struct device
4007 * @match: Callback function to check device
4008 * @data: Data to pass to match function
4010 * This is similar to the device_for_each_child() function above, but it
4011 * returns a reference to a device that is 'found' for later use, as
4012 * determined by the @match callback.
4014 * The callback should return 0 if the device doesn't match and non-zero
4015 * if it does. If the callback returns non-zero and a reference to the
4016 * current device can be obtained, this function will return to the caller
4017 * and not iterate over any more devices.
4019 * NOTE: you will need to drop the reference with put_device() after use.
4021 struct device *device_find_child(struct device *parent, void *data,
4022 int (*match)(struct device *dev, void *data))
4024 struct klist_iter i;
4025 struct device *child;
4030 klist_iter_init(&parent->p->klist_children, &i);
4031 while ((child = next_device(&i)))
4032 if (match(child, data) && get_device(child))
4034 klist_iter_exit(&i);
4037 EXPORT_SYMBOL_GPL(device_find_child);
4040 * device_find_child_by_name - device iterator for locating a child device.
4041 * @parent: parent struct device
4042 * @name: name of the child device
4044 * This is similar to the device_find_child() function above, but it
4045 * returns a reference to a device that has the name @name.
4047 * NOTE: you will need to drop the reference with put_device() after use.
4049 struct device *device_find_child_by_name(struct device *parent,
4052 struct klist_iter i;
4053 struct device *child;
4058 klist_iter_init(&parent->p->klist_children, &i);
4059 while ((child = next_device(&i)))
4060 if (sysfs_streq(dev_name(child), name) && get_device(child))
4062 klist_iter_exit(&i);
4065 EXPORT_SYMBOL_GPL(device_find_child_by_name);
4067 static int match_any(struct device *dev, void *unused)
4073 * device_find_any_child - device iterator for locating a child device, if any.
4074 * @parent: parent struct device
4076 * This is similar to the device_find_child() function above, but it
4077 * returns a reference to a child device, if any.
4079 * NOTE: you will need to drop the reference with put_device() after use.
4081 struct device *device_find_any_child(struct device *parent)
4083 return device_find_child(parent, NULL, match_any);
4085 EXPORT_SYMBOL_GPL(device_find_any_child);
4087 int __init devices_init(void)
4089 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
4092 dev_kobj = kobject_create_and_add("dev", NULL);
4095 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
4096 if (!sysfs_dev_block_kobj)
4097 goto block_kobj_err;
4098 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
4099 if (!sysfs_dev_char_kobj)
4105 kobject_put(sysfs_dev_block_kobj);
4107 kobject_put(dev_kobj);
4109 kset_unregister(devices_kset);
4113 static int device_check_offline(struct device *dev, void *not_used)
4117 ret = device_for_each_child(dev, NULL, device_check_offline);
4121 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
4125 * device_offline - Prepare the device for hot-removal.
4126 * @dev: Device to be put offline.
4128 * Execute the device bus type's .offline() callback, if present, to prepare
4129 * the device for a subsequent hot-removal. If that succeeds, the device must
4130 * not be used until either it is removed or its bus type's .online() callback
4133 * Call under device_hotplug_lock.
4135 int device_offline(struct device *dev)
4139 if (dev->offline_disabled)
4142 ret = device_for_each_child(dev, NULL, device_check_offline);
4147 if (device_supports_offline(dev)) {
4151 ret = dev->bus->offline(dev);
4153 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
4154 dev->offline = true;
4164 * device_online - Put the device back online after successful device_offline().
4165 * @dev: Device to be put back online.
4167 * If device_offline() has been successfully executed for @dev, but the device
4168 * has not been removed subsequently, execute its bus type's .online() callback
4169 * to indicate that the device can be used again.
4171 * Call under device_hotplug_lock.
4173 int device_online(struct device *dev)
4178 if (device_supports_offline(dev)) {
4180 ret = dev->bus->online(dev);
4182 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
4183 dev->offline = false;
4194 struct root_device {
4196 struct module *owner;
4199 static inline struct root_device *to_root_device(struct device *d)
4201 return container_of(d, struct root_device, dev);
4204 static void root_device_release(struct device *dev)
4206 kfree(to_root_device(dev));
4210 * __root_device_register - allocate and register a root device
4211 * @name: root device name
4212 * @owner: owner module of the root device, usually THIS_MODULE
4214 * This function allocates a root device and registers it
4215 * using device_register(). In order to free the returned
4216 * device, use root_device_unregister().
4218 * Root devices are dummy devices which allow other devices
4219 * to be grouped under /sys/devices. Use this function to
4220 * allocate a root device and then use it as the parent of
4221 * any device which should appear under /sys/devices/{name}
4223 * The /sys/devices/{name} directory will also contain a
4224 * 'module' symlink which points to the @owner directory
4227 * Returns &struct device pointer on success, or ERR_PTR() on error.
4229 * Note: You probably want to use root_device_register().
4231 struct device *__root_device_register(const char *name, struct module *owner)
4233 struct root_device *root;
4236 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
4238 return ERR_PTR(err);
4240 err = dev_set_name(&root->dev, "%s", name);
4243 return ERR_PTR(err);
4246 root->dev.release = root_device_release;
4248 err = device_register(&root->dev);
4250 put_device(&root->dev);
4251 return ERR_PTR(err);
4254 #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
4256 struct module_kobject *mk = &owner->mkobj;
4258 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
4260 device_unregister(&root->dev);
4261 return ERR_PTR(err);
4263 root->owner = owner;
4269 EXPORT_SYMBOL_GPL(__root_device_register);
4272 * root_device_unregister - unregister and free a root device
4273 * @dev: device going away
4275 * This function unregisters and cleans up a device that was created by
4276 * root_device_register().
4278 void root_device_unregister(struct device *dev)
4280 struct root_device *root = to_root_device(dev);
4283 sysfs_remove_link(&root->dev.kobj, "module");
4285 device_unregister(dev);
4287 EXPORT_SYMBOL_GPL(root_device_unregister);
4290 static void device_create_release(struct device *dev)
4292 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4296 static __printf(6, 0) struct device *
4297 device_create_groups_vargs(const struct class *class, struct device *parent,
4298 dev_t devt, void *drvdata,
4299 const struct attribute_group **groups,
4300 const char *fmt, va_list args)
4302 struct device *dev = NULL;
4303 int retval = -ENODEV;
4305 if (IS_ERR_OR_NULL(class))
4308 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4314 device_initialize(dev);
4317 dev->parent = parent;
4318 dev->groups = groups;
4319 dev->release = device_create_release;
4320 dev_set_drvdata(dev, drvdata);
4322 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4326 retval = device_add(dev);
4334 return ERR_PTR(retval);
4338 * device_create - creates a device and registers it with sysfs
4339 * @class: pointer to the struct class that this device should be registered to
4340 * @parent: pointer to the parent struct device of this new device, if any
4341 * @devt: the dev_t for the char device to be added
4342 * @drvdata: the data to be added to the device for callbacks
4343 * @fmt: string for the device's name
4345 * This function can be used by char device classes. A struct device
4346 * will be created in sysfs, registered to the specified class.
4348 * A "dev" file will be created, showing the dev_t for the device, if
4349 * the dev_t is not 0,0.
4350 * If a pointer to a parent struct device is passed in, the newly created
4351 * struct device will be a child of that device in sysfs.
4352 * The pointer to the struct device will be returned from the call.
4353 * Any further sysfs files that might be required can be created using this
4356 * Returns &struct device pointer on success, or ERR_PTR() on error.
4358 struct device *device_create(const struct class *class, struct device *parent,
4359 dev_t devt, void *drvdata, const char *fmt, ...)
4364 va_start(vargs, fmt);
4365 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4370 EXPORT_SYMBOL_GPL(device_create);
4373 * device_create_with_groups - creates a device and registers it with sysfs
4374 * @class: pointer to the struct class that this device should be registered to
4375 * @parent: pointer to the parent struct device of this new device, if any
4376 * @devt: the dev_t for the char device to be added
4377 * @drvdata: the data to be added to the device for callbacks
4378 * @groups: NULL-terminated list of attribute groups to be created
4379 * @fmt: string for the device's name
4381 * This function can be used by char device classes. A struct device
4382 * will be created in sysfs, registered to the specified class.
4383 * Additional attributes specified in the groups parameter will also
4384 * be created automatically.
4386 * A "dev" file will be created, showing the dev_t for the device, if
4387 * the dev_t is not 0,0.
4388 * If a pointer to a parent struct device is passed in, the newly created
4389 * struct device will be a child of that device in sysfs.
4390 * The pointer to the struct device will be returned from the call.
4391 * Any further sysfs files that might be required can be created using this
4394 * Returns &struct device pointer on success, or ERR_PTR() on error.
4396 struct device *device_create_with_groups(const struct class *class,
4397 struct device *parent, dev_t devt,
4399 const struct attribute_group **groups,
4400 const char *fmt, ...)
4405 va_start(vargs, fmt);
4406 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4411 EXPORT_SYMBOL_GPL(device_create_with_groups);
4414 * device_destroy - removes a device that was created with device_create()
4415 * @class: pointer to the struct class that this device was registered with
4416 * @devt: the dev_t of the device that was previously registered
4418 * This call unregisters and cleans up a device that was created with a
4419 * call to device_create().
4421 void device_destroy(const struct class *class, dev_t devt)
4425 dev = class_find_device_by_devt(class, devt);
4428 device_unregister(dev);
4431 EXPORT_SYMBOL_GPL(device_destroy);
4434 * device_rename - renames a device
4435 * @dev: the pointer to the struct device to be renamed
4436 * @new_name: the new name of the device
4438 * It is the responsibility of the caller to provide mutual
4439 * exclusion between two different calls of device_rename
4440 * on the same device to ensure that new_name is valid and
4441 * won't conflict with other devices.
4443 * Note: given that some subsystems (networking and infiniband) use this
4444 * function, with no immediate plans for this to change, we cannot assume or
4445 * require that this function not be called at all.
4447 * However, if you're writing new code, do not call this function. The following
4448 * text from Kay Sievers offers some insight:
4450 * Renaming devices is racy at many levels, symlinks and other stuff are not
4451 * replaced atomically, and you get a "move" uevent, but it's not easy to
4452 * connect the event to the old and new device. Device nodes are not renamed at
4453 * all, there isn't even support for that in the kernel now.
4455 * In the meantime, during renaming, your target name might be taken by another
4456 * driver, creating conflicts. Or the old name is taken directly after you
4457 * renamed it -- then you get events for the same DEVPATH, before you even see
4458 * the "move" event. It's just a mess, and nothing new should ever rely on
4459 * kernel device renaming. Besides that, it's not even implemented now for
4460 * other things than (driver-core wise very simple) network devices.
4462 * Make up a "real" name in the driver before you register anything, or add
4463 * some other attributes for userspace to find the device, or use udev to add
4464 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4465 * don't even want to get into that and try to implement the missing pieces in
4466 * the core. We really have other pieces to fix in the driver core mess. :)
4468 int device_rename(struct device *dev, const char *new_name)
4470 struct kobject *kobj = &dev->kobj;
4471 char *old_device_name = NULL;
4474 dev = get_device(dev);
4478 dev_dbg(dev, "renaming to %s\n", new_name);
4480 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4481 if (!old_device_name) {
4487 struct subsys_private *sp = class_to_subsys(dev->class);
4494 error = sysfs_rename_link_ns(&sp->subsys.kobj, kobj, old_device_name,
4495 new_name, kobject_namespace(kobj));
4501 error = kobject_rename(kobj, new_name);
4508 kfree(old_device_name);
4512 EXPORT_SYMBOL_GPL(device_rename);
4514 static int device_move_class_links(struct device *dev,
4515 struct device *old_parent,
4516 struct device *new_parent)
4521 sysfs_remove_link(&dev->kobj, "device");
4523 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4529 * device_move - moves a device to a new parent
4530 * @dev: the pointer to the struct device to be moved
4531 * @new_parent: the new parent of the device (can be NULL)
4532 * @dpm_order: how to reorder the dpm_list
4534 int device_move(struct device *dev, struct device *new_parent,
4535 enum dpm_order dpm_order)
4538 struct device *old_parent;
4539 struct kobject *new_parent_kobj;
4541 dev = get_device(dev);
4546 new_parent = get_device(new_parent);
4547 new_parent_kobj = get_device_parent(dev, new_parent);
4548 if (IS_ERR(new_parent_kobj)) {
4549 error = PTR_ERR(new_parent_kobj);
4550 put_device(new_parent);
4554 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4555 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4556 error = kobject_move(&dev->kobj, new_parent_kobj);
4558 cleanup_glue_dir(dev, new_parent_kobj);
4559 put_device(new_parent);
4562 old_parent = dev->parent;
4563 dev->parent = new_parent;
4565 klist_remove(&dev->p->knode_parent);
4567 klist_add_tail(&dev->p->knode_parent,
4568 &new_parent->p->klist_children);
4569 set_dev_node(dev, dev_to_node(new_parent));
4573 error = device_move_class_links(dev, old_parent, new_parent);
4575 /* We ignore errors on cleanup since we're hosed anyway... */
4576 device_move_class_links(dev, new_parent, old_parent);
4577 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4579 klist_remove(&dev->p->knode_parent);
4580 dev->parent = old_parent;
4582 klist_add_tail(&dev->p->knode_parent,
4583 &old_parent->p->klist_children);
4584 set_dev_node(dev, dev_to_node(old_parent));
4587 cleanup_glue_dir(dev, new_parent_kobj);
4588 put_device(new_parent);
4592 switch (dpm_order) {
4593 case DPM_ORDER_NONE:
4595 case DPM_ORDER_DEV_AFTER_PARENT:
4596 device_pm_move_after(dev, new_parent);
4597 devices_kset_move_after(dev, new_parent);
4599 case DPM_ORDER_PARENT_BEFORE_DEV:
4600 device_pm_move_before(new_parent, dev);
4601 devices_kset_move_before(new_parent, dev);
4603 case DPM_ORDER_DEV_LAST:
4604 device_pm_move_last(dev);
4605 devices_kset_move_last(dev);
4609 put_device(old_parent);
4615 EXPORT_SYMBOL_GPL(device_move);
4617 static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4620 struct kobject *kobj = &dev->kobj;
4621 const struct class *class = dev->class;
4622 const struct device_type *type = dev->type;
4627 * Change the device groups of the device class for @dev to
4630 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4638 * Change the device groups of the device type for @dev to
4641 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4647 /* Change the device groups of @dev to @kuid/@kgid. */
4648 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4652 if (device_supports_offline(dev) && !dev->offline_disabled) {
4653 /* Change online device attributes of @dev to @kuid/@kgid. */
4654 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4664 * device_change_owner - change the owner of an existing device.
4666 * @kuid: new owner's kuid
4667 * @kgid: new owner's kgid
4669 * This changes the owner of @dev and its corresponding sysfs entries to
4670 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4673 * Returns 0 on success or error code on failure.
4675 int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4678 struct kobject *kobj = &dev->kobj;
4679 struct subsys_private *sp;
4681 dev = get_device(dev);
4686 * Change the kobject and the default attributes and groups of the
4687 * ktype associated with it to @kuid/@kgid.
4689 error = sysfs_change_owner(kobj, kuid, kgid);
4694 * Change the uevent file for @dev to the new owner. The uevent file
4695 * was created in a separate step when @dev got added and we mirror
4698 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4704 * Change the device groups, the device groups associated with the
4705 * device class, and the groups associated with the device type of @dev
4708 error = device_attrs_change_owner(dev, kuid, kgid);
4712 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4717 * Change the owner of the symlink located in the class directory of
4718 * the device class associated with @dev which points to the actual
4719 * directory entry for @dev to @kuid/@kgid. This ensures that the
4720 * symlink shows the same permissions as its target.
4722 sp = class_to_subsys(dev->class);
4727 error = sysfs_link_change_owner(&sp->subsys.kobj, &dev->kobj, dev_name(dev), kuid, kgid);
4734 EXPORT_SYMBOL_GPL(device_change_owner);
4737 * device_shutdown - call ->shutdown() on each device to shutdown.
4739 void device_shutdown(void)
4741 struct device *dev, *parent;
4743 wait_for_device_probe();
4744 device_block_probing();
4748 spin_lock(&devices_kset->list_lock);
4750 * Walk the devices list backward, shutting down each in turn.
4751 * Beware that device unplug events may also start pulling
4752 * devices offline, even as the system is shutting down.
4754 while (!list_empty(&devices_kset->list)) {
4755 dev = list_entry(devices_kset->list.prev, struct device,
4759 * hold reference count of device's parent to
4760 * prevent it from being freed because parent's
4761 * lock is to be held
4763 parent = get_device(dev->parent);
4766 * Make sure the device is off the kset list, in the
4767 * event that dev->*->shutdown() doesn't remove it.
4769 list_del_init(&dev->kobj.entry);
4770 spin_unlock(&devices_kset->list_lock);
4772 /* hold lock to avoid race with probe/release */
4774 device_lock(parent);
4777 /* Don't allow any more runtime suspends */
4778 pm_runtime_get_noresume(dev);
4779 pm_runtime_barrier(dev);
4781 if (dev->class && dev->class->shutdown_pre) {
4783 dev_info(dev, "shutdown_pre\n");
4784 dev->class->shutdown_pre(dev);
4786 if (dev->bus && dev->bus->shutdown) {
4788 dev_info(dev, "shutdown\n");
4789 dev->bus->shutdown(dev);
4790 } else if (dev->driver && dev->driver->shutdown) {
4792 dev_info(dev, "shutdown\n");
4793 dev->driver->shutdown(dev);
4798 device_unlock(parent);
4803 spin_lock(&devices_kset->list_lock);
4805 spin_unlock(&devices_kset->list_lock);
4809 * Device logging functions
4812 #ifdef CONFIG_PRINTK
4814 set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4818 memset(dev_info, 0, sizeof(*dev_info));
4821 subsys = dev->class->name;
4823 subsys = dev->bus->name;
4827 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4830 * Add device identifier DEVICE=:
4834 * +sound:card0 subsystem:devname
4836 if (MAJOR(dev->devt)) {
4839 if (strcmp(subsys, "block") == 0)
4844 snprintf(dev_info->device, sizeof(dev_info->device),
4845 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4846 } else if (strcmp(subsys, "net") == 0) {
4847 struct net_device *net = to_net_dev(dev);
4849 snprintf(dev_info->device, sizeof(dev_info->device),
4850 "n%u", net->ifindex);
4852 snprintf(dev_info->device, sizeof(dev_info->device),
4853 "+%s:%s", subsys, dev_name(dev));
4857 int dev_vprintk_emit(int level, const struct device *dev,
4858 const char *fmt, va_list args)
4860 struct dev_printk_info dev_info;
4862 set_dev_info(dev, &dev_info);
4864 return vprintk_emit(0, level, &dev_info, fmt, args);
4866 EXPORT_SYMBOL(dev_vprintk_emit);
4868 int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4873 va_start(args, fmt);
4875 r = dev_vprintk_emit(level, dev, fmt, args);
4881 EXPORT_SYMBOL(dev_printk_emit);
4883 static void __dev_printk(const char *level, const struct device *dev,
4884 struct va_format *vaf)
4887 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4888 dev_driver_string(dev), dev_name(dev), vaf);
4890 printk("%s(NULL device *): %pV", level, vaf);
4893 void _dev_printk(const char *level, const struct device *dev,
4894 const char *fmt, ...)
4896 struct va_format vaf;
4899 va_start(args, fmt);
4904 __dev_printk(level, dev, &vaf);
4908 EXPORT_SYMBOL(_dev_printk);
4910 #define define_dev_printk_level(func, kern_level) \
4911 void func(const struct device *dev, const char *fmt, ...) \
4913 struct va_format vaf; \
4916 va_start(args, fmt); \
4921 __dev_printk(kern_level, dev, &vaf); \
4925 EXPORT_SYMBOL(func);
4927 define_dev_printk_level(_dev_emerg, KERN_EMERG);
4928 define_dev_printk_level(_dev_alert, KERN_ALERT);
4929 define_dev_printk_level(_dev_crit, KERN_CRIT);
4930 define_dev_printk_level(_dev_err, KERN_ERR);
4931 define_dev_printk_level(_dev_warn, KERN_WARNING);
4932 define_dev_printk_level(_dev_notice, KERN_NOTICE);
4933 define_dev_printk_level(_dev_info, KERN_INFO);
4938 * dev_err_probe - probe error check and log helper
4939 * @dev: the pointer to the struct device
4940 * @err: error value to test
4941 * @fmt: printf-style format string
4942 * @...: arguments as specified in the format string
4944 * This helper implements common pattern present in probe functions for error
4945 * checking: print debug or error message depending if the error value is
4946 * -EPROBE_DEFER and propagate error upwards.
4947 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4948 * checked later by reading devices_deferred debugfs attribute.
4949 * It replaces code sequence::
4951 * if (err != -EPROBE_DEFER)
4952 * dev_err(dev, ...);
4954 * dev_dbg(dev, ...);
4959 * return dev_err_probe(dev, err, ...);
4961 * Using this helper in your probe function is totally fine even if @err is
4962 * known to never be -EPROBE_DEFER.
4963 * The benefit compared to a normal dev_err() is the standardized format
4964 * of the error code, it being emitted symbolically (i.e. you get "EAGAIN"
4965 * instead of "-35") and the fact that the error code is returned which allows
4966 * more compact error paths.
4970 int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4972 struct va_format vaf;
4975 va_start(args, fmt);
4979 if (err != -EPROBE_DEFER) {
4980 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4982 device_set_deferred_probe_reason(dev, &vaf);
4983 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
4990 EXPORT_SYMBOL_GPL(dev_err_probe);
4992 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
4994 return fwnode && !IS_ERR(fwnode->secondary);
4998 * set_primary_fwnode - Change the primary firmware node of a given device.
4999 * @dev: Device to handle.
5000 * @fwnode: New primary firmware node of the device.
5002 * Set the device's firmware node pointer to @fwnode, but if a secondary
5003 * firmware node of the device is present, preserve it.
5005 * Valid fwnode cases are:
5006 * - primary --> secondary --> -ENODEV
5007 * - primary --> NULL
5008 * - secondary --> -ENODEV
5011 void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5013 struct device *parent = dev->parent;
5014 struct fwnode_handle *fn = dev->fwnode;
5017 if (fwnode_is_primary(fn))
5021 WARN_ON(fwnode->secondary);
5022 fwnode->secondary = fn;
5024 dev->fwnode = fwnode;
5026 if (fwnode_is_primary(fn)) {
5027 dev->fwnode = fn->secondary;
5029 /* Skip nullifying fn->secondary if the primary is shared */
5030 if (parent && fn == parent->fwnode)
5033 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
5034 fn->secondary = NULL;
5040 EXPORT_SYMBOL_GPL(set_primary_fwnode);
5043 * set_secondary_fwnode - Change the secondary firmware node of a given device.
5044 * @dev: Device to handle.
5045 * @fwnode: New secondary firmware node of the device.
5047 * If a primary firmware node of the device is present, set its secondary
5048 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
5051 void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5054 fwnode->secondary = ERR_PTR(-ENODEV);
5056 if (fwnode_is_primary(dev->fwnode))
5057 dev->fwnode->secondary = fwnode;
5059 dev->fwnode = fwnode;
5061 EXPORT_SYMBOL_GPL(set_secondary_fwnode);
5064 * device_set_of_node_from_dev - reuse device-tree node of another device
5065 * @dev: device whose device-tree node is being set
5066 * @dev2: device whose device-tree node is being reused
5068 * Takes another reference to the new device-tree node after first dropping
5069 * any reference held to the old node.
5071 void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
5073 of_node_put(dev->of_node);
5074 dev->of_node = of_node_get(dev2->of_node);
5075 dev->of_node_reused = true;
5077 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
5079 void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
5081 dev->fwnode = fwnode;
5082 dev->of_node = to_of_node(fwnode);
5084 EXPORT_SYMBOL_GPL(device_set_node);
5086 int device_match_name(struct device *dev, const void *name)
5088 return sysfs_streq(dev_name(dev), name);
5090 EXPORT_SYMBOL_GPL(device_match_name);
5092 int device_match_of_node(struct device *dev, const void *np)
5094 return dev->of_node == np;
5096 EXPORT_SYMBOL_GPL(device_match_of_node);
5098 int device_match_fwnode(struct device *dev, const void *fwnode)
5100 return dev_fwnode(dev) == fwnode;
5102 EXPORT_SYMBOL_GPL(device_match_fwnode);
5104 int device_match_devt(struct device *dev, const void *pdevt)
5106 return dev->devt == *(dev_t *)pdevt;
5108 EXPORT_SYMBOL_GPL(device_match_devt);
5110 int device_match_acpi_dev(struct device *dev, const void *adev)
5112 return ACPI_COMPANION(dev) == adev;
5114 EXPORT_SYMBOL(device_match_acpi_dev);
5116 int device_match_acpi_handle(struct device *dev, const void *handle)
5118 return ACPI_HANDLE(dev) == handle;
5120 EXPORT_SYMBOL(device_match_acpi_handle);
5122 int device_match_any(struct device *dev, const void *unused)
5126 EXPORT_SYMBOL_GPL(device_match_any);