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;
47 static struct workqueue_struct *device_link_wq;
50 * __fwnode_link_add - Create a link between two fwnode_handles.
51 * @con: Consumer end of the link.
52 * @sup: Supplier end of the link.
55 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
56 * represents the detail that the firmware lists @sup fwnode as supplying a
59 * The driver core will use the fwnode link to create a device link between the
60 * two device objects corresponding to @con and @sup when they are created. The
61 * driver core will automatically delete the fwnode link between @con and @sup
64 * Attempts to create duplicate links between the same pair of fwnode handles
65 * are ignored and there is no reference counting.
67 static int __fwnode_link_add(struct fwnode_handle *con,
68 struct fwnode_handle *sup, u8 flags)
70 struct fwnode_link *link;
72 list_for_each_entry(link, &sup->consumers, s_hook)
73 if (link->consumer == con) {
78 link = kzalloc(sizeof(*link), GFP_KERNEL);
83 INIT_LIST_HEAD(&link->s_hook);
85 INIT_LIST_HEAD(&link->c_hook);
88 list_add(&link->s_hook, &sup->consumers);
89 list_add(&link->c_hook, &con->suppliers);
90 pr_debug("%pfwf Linked as a fwnode consumer to %pfwf\n",
96 int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
100 mutex_lock(&fwnode_link_lock);
101 ret = __fwnode_link_add(con, sup, 0);
102 mutex_unlock(&fwnode_link_lock);
107 * __fwnode_link_del - Delete a link between two fwnode_handles.
108 * @link: the fwnode_link to be deleted
110 * The fwnode_link_lock needs to be held when this function is called.
112 static void __fwnode_link_del(struct fwnode_link *link)
114 pr_debug("%pfwf Dropping the fwnode link to %pfwf\n",
115 link->consumer, link->supplier);
116 list_del(&link->s_hook);
117 list_del(&link->c_hook);
122 * __fwnode_link_cycle - Mark a fwnode link as being part of a cycle.
123 * @link: the fwnode_link to be marked
125 * The fwnode_link_lock needs to be held when this function is called.
127 static void __fwnode_link_cycle(struct fwnode_link *link)
129 pr_debug("%pfwf: cycle: depends on %pfwf\n",
130 link->consumer, link->supplier);
131 link->flags |= FWLINK_FLAG_CYCLE;
135 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
136 * @fwnode: fwnode whose supplier links need to be deleted
138 * Deletes all supplier links connecting directly to @fwnode.
140 static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
142 struct fwnode_link *link, *tmp;
144 mutex_lock(&fwnode_link_lock);
145 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
146 __fwnode_link_del(link);
147 mutex_unlock(&fwnode_link_lock);
151 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle.
152 * @fwnode: fwnode whose consumer links need to be deleted
154 * Deletes all consumer links connecting directly to @fwnode.
156 static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
158 struct fwnode_link *link, *tmp;
160 mutex_lock(&fwnode_link_lock);
161 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
162 __fwnode_link_del(link);
163 mutex_unlock(&fwnode_link_lock);
167 * fwnode_links_purge - Delete all links connected to a fwnode_handle.
168 * @fwnode: fwnode whose links needs to be deleted
170 * Deletes all links connecting directly to a fwnode.
172 void fwnode_links_purge(struct fwnode_handle *fwnode)
174 fwnode_links_purge_suppliers(fwnode);
175 fwnode_links_purge_consumers(fwnode);
178 void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode)
180 struct fwnode_handle *child;
182 /* Don't purge consumer links of an added child */
186 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
187 fwnode_links_purge_consumers(fwnode);
189 fwnode_for_each_available_child_node(fwnode, child)
190 fw_devlink_purge_absent_suppliers(child);
192 EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers);
195 * __fwnode_links_move_consumers - Move consumer from @from to @to fwnode_handle
196 * @from: move consumers away from this fwnode
197 * @to: move consumers to this fwnode
199 * Move all consumer links from @from fwnode to @to fwnode.
201 static void __fwnode_links_move_consumers(struct fwnode_handle *from,
202 struct fwnode_handle *to)
204 struct fwnode_link *link, *tmp;
206 list_for_each_entry_safe(link, tmp, &from->consumers, s_hook) {
207 __fwnode_link_add(link->consumer, to, link->flags);
208 __fwnode_link_del(link);
213 * __fw_devlink_pickup_dangling_consumers - Pick up dangling consumers
214 * @fwnode: fwnode from which to pick up dangling consumers
215 * @new_sup: fwnode of new supplier
217 * If the @fwnode has a corresponding struct device and the device supports
218 * probing (that is, added to a bus), then we want to let fw_devlink create
219 * MANAGED device links to this device, so leave @fwnode and its descendant's
220 * fwnode links alone.
222 * Otherwise, move its consumers to the new supplier @new_sup.
224 static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode,
225 struct fwnode_handle *new_sup)
227 struct fwnode_handle *child;
229 if (fwnode->dev && fwnode->dev->bus)
232 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;
233 __fwnode_links_move_consumers(fwnode, new_sup);
235 fwnode_for_each_available_child_node(fwnode, child)
236 __fw_devlink_pickup_dangling_consumers(child, new_sup);
239 static DEFINE_MUTEX(device_links_lock);
240 DEFINE_STATIC_SRCU(device_links_srcu);
242 static inline void device_links_write_lock(void)
244 mutex_lock(&device_links_lock);
247 static inline void device_links_write_unlock(void)
249 mutex_unlock(&device_links_lock);
252 int device_links_read_lock(void) __acquires(&device_links_srcu)
254 return srcu_read_lock(&device_links_srcu);
257 void device_links_read_unlock(int idx) __releases(&device_links_srcu)
259 srcu_read_unlock(&device_links_srcu, idx);
262 int device_links_read_lock_held(void)
264 return srcu_read_lock_held(&device_links_srcu);
267 static void device_link_synchronize_removal(void)
269 synchronize_srcu(&device_links_srcu);
272 static void device_link_remove_from_lists(struct device_link *link)
274 list_del_rcu(&link->s_node);
275 list_del_rcu(&link->c_node);
278 static bool device_is_ancestor(struct device *dev, struct device *target)
280 while (target->parent) {
281 target = target->parent;
288 #define DL_MARKER_FLAGS (DL_FLAG_INFERRED | \
291 static inline bool device_link_flag_is_sync_state_only(u32 flags)
293 return (flags & ~DL_MARKER_FLAGS) == DL_FLAG_SYNC_STATE_ONLY;
297 * device_is_dependent - Check if one device depends on another one
298 * @dev: Device to check dependencies for.
299 * @target: Device to check against.
301 * Check if @target depends on @dev or any device dependent on it (its child or
302 * its consumer etc). Return 1 if that is the case or 0 otherwise.
304 static int device_is_dependent(struct device *dev, void *target)
306 struct device_link *link;
310 * The "ancestors" check is needed to catch the case when the target
311 * device has not been completely initialized yet and it is still
312 * missing from the list of children of its parent device.
314 if (dev == target || device_is_ancestor(dev, target))
317 ret = device_for_each_child(dev, target, device_is_dependent);
321 list_for_each_entry(link, &dev->links.consumers, s_node) {
322 if (device_link_flag_is_sync_state_only(link->flags))
325 if (link->consumer == target)
328 ret = device_is_dependent(link->consumer, target);
335 static void device_link_init_status(struct device_link *link,
336 struct device *consumer,
337 struct device *supplier)
339 switch (supplier->links.status) {
341 switch (consumer->links.status) {
344 * A consumer driver can create a link to a supplier
345 * that has not completed its probing yet as long as it
346 * knows that the supplier is already functional (for
347 * example, it has just acquired some resources from the
350 link->status = DL_STATE_CONSUMER_PROBE;
353 link->status = DL_STATE_DORMANT;
357 case DL_DEV_DRIVER_BOUND:
358 switch (consumer->links.status) {
360 link->status = DL_STATE_CONSUMER_PROBE;
362 case DL_DEV_DRIVER_BOUND:
363 link->status = DL_STATE_ACTIVE;
366 link->status = DL_STATE_AVAILABLE;
370 case DL_DEV_UNBINDING:
371 link->status = DL_STATE_SUPPLIER_UNBIND;
374 link->status = DL_STATE_DORMANT;
379 static int device_reorder_to_tail(struct device *dev, void *not_used)
381 struct device_link *link;
384 * Devices that have not been registered yet will be put to the ends
385 * of the lists during the registration, so skip them here.
387 if (device_is_registered(dev))
388 devices_kset_move_last(dev);
390 if (device_pm_initialized(dev))
391 device_pm_move_last(dev);
393 device_for_each_child(dev, NULL, device_reorder_to_tail);
394 list_for_each_entry(link, &dev->links.consumers, s_node) {
395 if (device_link_flag_is_sync_state_only(link->flags))
397 device_reorder_to_tail(link->consumer, NULL);
404 * device_pm_move_to_tail - Move set of devices to the end of device lists
405 * @dev: Device to move
407 * This is a device_reorder_to_tail() wrapper taking the requisite locks.
409 * It moves the @dev along with all of its children and all of its consumers
410 * to the ends of the device_kset and dpm_list, recursively.
412 void device_pm_move_to_tail(struct device *dev)
416 idx = device_links_read_lock();
418 device_reorder_to_tail(dev, NULL);
420 device_links_read_unlock(idx);
423 #define to_devlink(dev) container_of((dev), struct device_link, link_dev)
425 static ssize_t status_show(struct device *dev,
426 struct device_attribute *attr, char *buf)
430 switch (to_devlink(dev)->status) {
432 output = "not tracked";
434 case DL_STATE_DORMANT:
437 case DL_STATE_AVAILABLE:
438 output = "available";
440 case DL_STATE_CONSUMER_PROBE:
441 output = "consumer probing";
443 case DL_STATE_ACTIVE:
446 case DL_STATE_SUPPLIER_UNBIND:
447 output = "supplier unbinding";
454 return sysfs_emit(buf, "%s\n", output);
456 static DEVICE_ATTR_RO(status);
458 static ssize_t auto_remove_on_show(struct device *dev,
459 struct device_attribute *attr, char *buf)
461 struct device_link *link = to_devlink(dev);
464 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
465 output = "supplier unbind";
466 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
467 output = "consumer unbind";
471 return sysfs_emit(buf, "%s\n", output);
473 static DEVICE_ATTR_RO(auto_remove_on);
475 static ssize_t runtime_pm_show(struct device *dev,
476 struct device_attribute *attr, char *buf)
478 struct device_link *link = to_devlink(dev);
480 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME));
482 static DEVICE_ATTR_RO(runtime_pm);
484 static ssize_t sync_state_only_show(struct device *dev,
485 struct device_attribute *attr, char *buf)
487 struct device_link *link = to_devlink(dev);
489 return sysfs_emit(buf, "%d\n",
490 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
492 static DEVICE_ATTR_RO(sync_state_only);
494 static struct attribute *devlink_attrs[] = {
495 &dev_attr_status.attr,
496 &dev_attr_auto_remove_on.attr,
497 &dev_attr_runtime_pm.attr,
498 &dev_attr_sync_state_only.attr,
501 ATTRIBUTE_GROUPS(devlink);
503 static void device_link_release_fn(struct work_struct *work)
505 struct device_link *link = container_of(work, struct device_link, rm_work);
507 /* Ensure that all references to the link object have been dropped. */
508 device_link_synchronize_removal();
510 pm_runtime_release_supplier(link);
512 * If supplier_preactivated is set, the link has been dropped between
513 * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls
514 * in __driver_probe_device(). In that case, drop the supplier's
515 * PM-runtime usage counter to remove the reference taken by
516 * pm_runtime_get_suppliers().
518 if (link->supplier_preactivated)
519 pm_runtime_put_noidle(link->supplier);
521 pm_request_idle(link->supplier);
523 put_device(link->consumer);
524 put_device(link->supplier);
528 static void devlink_dev_release(struct device *dev)
530 struct device_link *link = to_devlink(dev);
532 INIT_WORK(&link->rm_work, device_link_release_fn);
534 * It may take a while to complete this work because of the SRCU
535 * synchronization in device_link_release_fn() and if the consumer or
536 * supplier devices get deleted when it runs, so put it into the
537 * dedicated workqueue.
539 queue_work(device_link_wq, &link->rm_work);
543 * device_link_wait_removal - Wait for ongoing devlink removal jobs to terminate
545 void device_link_wait_removal(void)
548 * devlink removal jobs are queued in the dedicated work queue.
549 * To be sure that all removal jobs are terminated, ensure that any
550 * scheduled work has run to completion.
552 flush_workqueue(device_link_wq);
554 EXPORT_SYMBOL_GPL(device_link_wait_removal);
556 static struct class devlink_class = {
558 .dev_groups = devlink_groups,
559 .dev_release = devlink_dev_release,
562 static int devlink_add_symlinks(struct device *dev)
566 struct device_link *link = to_devlink(dev);
567 struct device *sup = link->supplier;
568 struct device *con = link->consumer;
571 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
572 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
574 len += strlen("supplier:") + 1;
575 buf = kzalloc(len, GFP_KERNEL);
579 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier");
583 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer");
587 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
588 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf);
592 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
593 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf);
600 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
601 sysfs_remove_link(&sup->kobj, buf);
603 sysfs_remove_link(&link->link_dev.kobj, "consumer");
605 sysfs_remove_link(&link->link_dev.kobj, "supplier");
611 static void devlink_remove_symlinks(struct device *dev)
613 struct device_link *link = to_devlink(dev);
615 struct device *sup = link->supplier;
616 struct device *con = link->consumer;
619 sysfs_remove_link(&link->link_dev.kobj, "consumer");
620 sysfs_remove_link(&link->link_dev.kobj, "supplier");
622 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)),
623 strlen(dev_bus_name(con)) + strlen(dev_name(con)));
625 len += strlen("supplier:") + 1;
626 buf = kzalloc(len, GFP_KERNEL);
628 WARN(1, "Unable to properly free device link symlinks!\n");
632 if (device_is_registered(con)) {
633 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup));
634 sysfs_remove_link(&con->kobj, buf);
636 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con));
637 sysfs_remove_link(&sup->kobj, buf);
641 static struct class_interface devlink_class_intf = {
642 .class = &devlink_class,
643 .add_dev = devlink_add_symlinks,
644 .remove_dev = devlink_remove_symlinks,
647 static int __init devlink_class_init(void)
651 ret = class_register(&devlink_class);
655 ret = class_interface_register(&devlink_class_intf);
657 class_unregister(&devlink_class);
661 postcore_initcall(devlink_class_init);
663 #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
664 DL_FLAG_AUTOREMOVE_SUPPLIER | \
665 DL_FLAG_AUTOPROBE_CONSUMER | \
666 DL_FLAG_SYNC_STATE_ONLY | \
670 #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
671 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
674 * device_link_add - Create a link between two devices.
675 * @consumer: Consumer end of the link.
676 * @supplier: Supplier end of the link.
677 * @flags: Link flags.
679 * The caller is responsible for the proper synchronization of the link creation
680 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
681 * runtime PM framework to take the link into account. Second, if the
682 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
683 * be forced into the active meta state and reference-counted upon the creation
684 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
687 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is
688 * expected to release the link returned by it directly with the help of either
689 * device_link_del() or device_link_remove().
691 * If that flag is not set, however, the caller of this function is handing the
692 * management of the link over to the driver core entirely and its return value
693 * can only be used to check whether or not the link is present. In that case,
694 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
695 * flags can be used to indicate to the driver core when the link can be safely
696 * deleted. Namely, setting one of them in @flags indicates to the driver core
697 * that the link is not going to be used (by the given caller of this function)
698 * after unbinding the consumer or supplier driver, respectively, from its
699 * device, so the link can be deleted at that point. If none of them is set,
700 * the link will be maintained until one of the devices pointed to by it (either
701 * the consumer or the supplier) is unregistered.
703 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
704 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
705 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
706 * be used to request the driver core to automatically probe for a consumer
707 * driver after successfully binding a driver to the supplier device.
709 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
710 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
711 * the same time is invalid and will cause NULL to be returned upfront.
712 * However, if a device link between the given @consumer and @supplier pair
713 * exists already when this function is called for them, the existing link will
714 * be returned regardless of its current type and status (the link's flags may
715 * be modified then). The caller of this function is then expected to treat
716 * the link as though it has just been created, so (in particular) if
717 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released
718 * explicitly when not needed any more (as stated above).
720 * A side effect of the link creation is re-ordering of dpm_list and the
721 * devices_kset list by moving the consumer device and all devices depending
722 * on it to the ends of these lists (that does not happen to devices that have
723 * not been registered when this function is called).
725 * The supplier device is required to be registered when this function is called
726 * and NULL will be returned if that is not the case. The consumer device need
727 * not be registered, however.
729 struct device_link *device_link_add(struct device *consumer,
730 struct device *supplier, u32 flags)
732 struct device_link *link;
734 if (!consumer || !supplier || consumer == supplier ||
735 flags & ~DL_ADD_VALID_FLAGS ||
736 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
737 (flags & DL_FLAG_AUTOPROBE_CONSUMER &&
738 flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
739 DL_FLAG_AUTOREMOVE_SUPPLIER)))
742 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
743 if (pm_runtime_get_sync(supplier) < 0) {
744 pm_runtime_put_noidle(supplier);
749 if (!(flags & DL_FLAG_STATELESS))
750 flags |= DL_FLAG_MANAGED;
752 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
753 !device_link_flag_is_sync_state_only(flags))
756 device_links_write_lock();
760 * If the supplier has not been fully registered yet or there is a
761 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and
762 * the supplier already in the graph, return NULL. If the link is a
763 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
764 * because it only affects sync_state() callbacks.
766 if (!device_pm_initialized(supplier)
767 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
768 device_is_dependent(consumer, supplier))) {
774 * SYNC_STATE_ONLY links are useless once a consumer device has probed.
775 * So, only create it if the consumer hasn't probed yet.
777 if (flags & DL_FLAG_SYNC_STATE_ONLY &&
778 consumer->links.status != DL_DEV_NO_DRIVER &&
779 consumer->links.status != DL_DEV_PROBING) {
785 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
786 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
787 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
789 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
790 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
792 list_for_each_entry(link, &supplier->links.consumers, s_node) {
793 if (link->consumer != consumer)
796 if (link->flags & DL_FLAG_INFERRED &&
797 !(flags & DL_FLAG_INFERRED))
798 link->flags &= ~DL_FLAG_INFERRED;
800 if (flags & DL_FLAG_PM_RUNTIME) {
801 if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
802 pm_runtime_new_link(consumer);
803 link->flags |= DL_FLAG_PM_RUNTIME;
805 if (flags & DL_FLAG_RPM_ACTIVE)
806 refcount_inc(&link->rpm_active);
809 if (flags & DL_FLAG_STATELESS) {
810 kref_get(&link->kref);
811 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
812 !(link->flags & DL_FLAG_STATELESS)) {
813 link->flags |= DL_FLAG_STATELESS;
816 link->flags |= DL_FLAG_STATELESS;
822 * If the life time of the link following from the new flags is
823 * longer than indicated by the flags of the existing link,
824 * update the existing link to stay around longer.
826 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
827 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
828 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
829 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
831 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
832 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
833 DL_FLAG_AUTOREMOVE_SUPPLIER);
835 if (!(link->flags & DL_FLAG_MANAGED)) {
836 kref_get(&link->kref);
837 link->flags |= DL_FLAG_MANAGED;
838 device_link_init_status(link, consumer, supplier);
840 if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
841 !(flags & DL_FLAG_SYNC_STATE_ONLY)) {
842 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;
849 link = kzalloc(sizeof(*link), GFP_KERNEL);
853 refcount_set(&link->rpm_active, 1);
855 get_device(supplier);
856 link->supplier = supplier;
857 INIT_LIST_HEAD(&link->s_node);
858 get_device(consumer);
859 link->consumer = consumer;
860 INIT_LIST_HEAD(&link->c_node);
862 kref_init(&link->kref);
864 link->link_dev.class = &devlink_class;
865 device_set_pm_not_required(&link->link_dev);
866 dev_set_name(&link->link_dev, "%s:%s--%s:%s",
867 dev_bus_name(supplier), dev_name(supplier),
868 dev_bus_name(consumer), dev_name(consumer));
869 if (device_register(&link->link_dev)) {
870 put_device(&link->link_dev);
875 if (flags & DL_FLAG_PM_RUNTIME) {
876 if (flags & DL_FLAG_RPM_ACTIVE)
877 refcount_inc(&link->rpm_active);
879 pm_runtime_new_link(consumer);
882 /* Determine the initial link state. */
883 if (flags & DL_FLAG_STATELESS)
884 link->status = DL_STATE_NONE;
886 device_link_init_status(link, consumer, supplier);
889 * Some callers expect the link creation during consumer driver probe to
890 * resume the supplier even without DL_FLAG_RPM_ACTIVE.
892 if (link->status == DL_STATE_CONSUMER_PROBE &&
893 flags & DL_FLAG_PM_RUNTIME)
894 pm_runtime_resume(supplier);
896 list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
897 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
899 if (flags & DL_FLAG_SYNC_STATE_ONLY) {
901 "Linked as a sync state only consumer to %s\n",
908 * Move the consumer and all of the devices depending on it to the end
909 * of dpm_list and the devices_kset list.
911 * It is necessary to hold dpm_list locked throughout all that or else
912 * we may end up suspending with a wrong ordering of it.
914 device_reorder_to_tail(consumer, NULL);
916 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier));
920 device_links_write_unlock();
922 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link)
923 pm_runtime_put(supplier);
927 EXPORT_SYMBOL_GPL(device_link_add);
929 static void __device_link_del(struct kref *kref)
931 struct device_link *link = container_of(kref, struct device_link, kref);
933 dev_dbg(link->consumer, "Dropping the link to %s\n",
934 dev_name(link->supplier));
936 pm_runtime_drop_link(link);
938 device_link_remove_from_lists(link);
939 device_unregister(&link->link_dev);
942 static void device_link_put_kref(struct device_link *link)
944 if (link->flags & DL_FLAG_STATELESS)
945 kref_put(&link->kref, __device_link_del);
946 else if (!device_is_registered(link->consumer))
947 __device_link_del(&link->kref);
949 WARN(1, "Unable to drop a managed device link reference\n");
953 * device_link_del - Delete a stateless link between two devices.
954 * @link: Device link to delete.
956 * The caller must ensure proper synchronization of this function with runtime
957 * PM. If the link was added multiple times, it needs to be deleted as often.
958 * Care is required for hotplugged devices: Their links are purged on removal
959 * and calling device_link_del() is then no longer allowed.
961 void device_link_del(struct device_link *link)
963 device_links_write_lock();
964 device_link_put_kref(link);
965 device_links_write_unlock();
967 EXPORT_SYMBOL_GPL(device_link_del);
970 * device_link_remove - Delete a stateless link between two devices.
971 * @consumer: Consumer end of the link.
972 * @supplier: Supplier end of the link.
974 * The caller must ensure proper synchronization of this function with runtime
977 void device_link_remove(void *consumer, struct device *supplier)
979 struct device_link *link;
981 if (WARN_ON(consumer == supplier))
984 device_links_write_lock();
986 list_for_each_entry(link, &supplier->links.consumers, s_node) {
987 if (link->consumer == consumer) {
988 device_link_put_kref(link);
993 device_links_write_unlock();
995 EXPORT_SYMBOL_GPL(device_link_remove);
997 static void device_links_missing_supplier(struct device *dev)
999 struct device_link *link;
1001 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1002 if (link->status != DL_STATE_CONSUMER_PROBE)
1005 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1006 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1008 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1009 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1014 static bool dev_is_best_effort(struct device *dev)
1016 return (fw_devlink_best_effort && dev->can_match) ||
1017 (dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));
1020 static struct fwnode_handle *fwnode_links_check_suppliers(
1021 struct fwnode_handle *fwnode)
1023 struct fwnode_link *link;
1025 if (!fwnode || fw_devlink_is_permissive())
1028 list_for_each_entry(link, &fwnode->suppliers, c_hook)
1029 if (!(link->flags & FWLINK_FLAG_CYCLE))
1030 return link->supplier;
1036 * device_links_check_suppliers - Check presence of supplier drivers.
1037 * @dev: Consumer device.
1039 * Check links from this device to any suppliers. Walk the list of the device's
1040 * links to suppliers and see if all of them are available. If not, simply
1041 * return -EPROBE_DEFER.
1043 * We need to guarantee that the supplier will not go away after the check has
1044 * been positive here. It only can go away in __device_release_driver() and
1045 * that function checks the device's links to consumers. This means we need to
1046 * mark the link as "consumer probe in progress" to make the supplier removal
1047 * wait for us to complete (or bad things may happen).
1049 * Links without the DL_FLAG_MANAGED flag set are ignored.
1051 int device_links_check_suppliers(struct device *dev)
1053 struct device_link *link;
1054 int ret = 0, fwnode_ret = 0;
1055 struct fwnode_handle *sup_fw;
1058 * Device waiting for supplier to become available is not allowed to
1061 mutex_lock(&fwnode_link_lock);
1062 sup_fw = fwnode_links_check_suppliers(dev->fwnode);
1064 if (!dev_is_best_effort(dev)) {
1065 fwnode_ret = -EPROBE_DEFER;
1066 dev_err_probe(dev, -EPROBE_DEFER,
1067 "wait for supplier %pfwf\n", sup_fw);
1069 fwnode_ret = -EAGAIN;
1072 mutex_unlock(&fwnode_link_lock);
1073 if (fwnode_ret == -EPROBE_DEFER)
1076 device_links_write_lock();
1078 list_for_each_entry(link, &dev->links.suppliers, c_node) {
1079 if (!(link->flags & DL_FLAG_MANAGED))
1082 if (link->status != DL_STATE_AVAILABLE &&
1083 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
1085 if (dev_is_best_effort(dev) &&
1086 link->flags & DL_FLAG_INFERRED &&
1087 !link->supplier->can_match) {
1092 device_links_missing_supplier(dev);
1093 dev_err_probe(dev, -EPROBE_DEFER,
1094 "supplier %s not ready\n",
1095 dev_name(link->supplier));
1096 ret = -EPROBE_DEFER;
1099 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1101 dev->links.status = DL_DEV_PROBING;
1103 device_links_write_unlock();
1105 return ret ? ret : fwnode_ret;
1109 * __device_links_queue_sync_state - Queue a device for sync_state() callback
1110 * @dev: Device to call sync_state() on
1111 * @list: List head to queue the @dev on
1113 * Queues a device for a sync_state() callback when the device links write lock
1114 * isn't held. This allows the sync_state() execution flow to use device links
1115 * APIs. The caller must ensure this function is called with
1116 * device_links_write_lock() held.
1118 * This function does a get_device() to make sure the device is not freed while
1121 * So the caller must also ensure that device_links_flush_sync_list() is called
1122 * as soon as the caller releases device_links_write_lock(). This is necessary
1123 * to make sure the sync_state() is called in a timely fashion and the
1124 * put_device() is called on this device.
1126 static void __device_links_queue_sync_state(struct device *dev,
1127 struct list_head *list)
1129 struct device_link *link;
1131 if (!dev_has_sync_state(dev))
1133 if (dev->state_synced)
1136 list_for_each_entry(link, &dev->links.consumers, s_node) {
1137 if (!(link->flags & DL_FLAG_MANAGED))
1139 if (link->status != DL_STATE_ACTIVE)
1144 * Set the flag here to avoid adding the same device to a list more
1145 * than once. This can happen if new consumers get added to the device
1146 * and probed before the list is flushed.
1148 dev->state_synced = true;
1150 if (WARN_ON(!list_empty(&dev->links.defer_sync)))
1154 list_add_tail(&dev->links.defer_sync, list);
1158 * device_links_flush_sync_list - Call sync_state() on a list of devices
1159 * @list: List of devices to call sync_state() on
1160 * @dont_lock_dev: Device for which lock is already held by the caller
1162 * Calls sync_state() on all the devices that have been queued for it. This
1163 * function is used in conjunction with __device_links_queue_sync_state(). The
1164 * @dont_lock_dev parameter is useful when this function is called from a
1165 * context where a device lock is already held.
1167 static void device_links_flush_sync_list(struct list_head *list,
1168 struct device *dont_lock_dev)
1170 struct device *dev, *tmp;
1172 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) {
1173 list_del_init(&dev->links.defer_sync);
1175 if (dev != dont_lock_dev)
1178 dev_sync_state(dev);
1180 if (dev != dont_lock_dev)
1187 void device_links_supplier_sync_state_pause(void)
1189 device_links_write_lock();
1190 defer_sync_state_count++;
1191 device_links_write_unlock();
1194 void device_links_supplier_sync_state_resume(void)
1196 struct device *dev, *tmp;
1197 LIST_HEAD(sync_list);
1199 device_links_write_lock();
1200 if (!defer_sync_state_count) {
1201 WARN(true, "Unmatched sync_state pause/resume!");
1204 defer_sync_state_count--;
1205 if (defer_sync_state_count)
1208 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) {
1210 * Delete from deferred_sync list before queuing it to
1211 * sync_list because defer_sync is used for both lists.
1213 list_del_init(&dev->links.defer_sync);
1214 __device_links_queue_sync_state(dev, &sync_list);
1217 device_links_write_unlock();
1219 device_links_flush_sync_list(&sync_list, NULL);
1222 static int sync_state_resume_initcall(void)
1224 device_links_supplier_sync_state_resume();
1227 late_initcall(sync_state_resume_initcall);
1229 static void __device_links_supplier_defer_sync(struct device *sup)
1231 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup))
1232 list_add_tail(&sup->links.defer_sync, &deferred_sync);
1235 static void device_link_drop_managed(struct device_link *link)
1237 link->flags &= ~DL_FLAG_MANAGED;
1238 WRITE_ONCE(link->status, DL_STATE_NONE);
1239 kref_put(&link->kref, __device_link_del);
1242 static ssize_t waiting_for_supplier_show(struct device *dev,
1243 struct device_attribute *attr,
1249 mutex_lock(&fwnode_link_lock);
1250 val = !!fwnode_links_check_suppliers(dev->fwnode);
1251 mutex_unlock(&fwnode_link_lock);
1253 return sysfs_emit(buf, "%u\n", val);
1255 static DEVICE_ATTR_RO(waiting_for_supplier);
1258 * device_links_force_bind - Prepares device to be force bound
1259 * @dev: Consumer device.
1261 * device_bind_driver() force binds a device to a driver without calling any
1262 * driver probe functions. So the consumer really isn't going to wait for any
1263 * supplier before it's bound to the driver. We still want the device link
1264 * states to be sensible when this happens.
1266 * In preparation for device_bind_driver(), this function goes through each
1267 * supplier device links and checks if the supplier is bound. If it is, then
1268 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link
1269 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored.
1271 void device_links_force_bind(struct device *dev)
1273 struct device_link *link, *ln;
1275 device_links_write_lock();
1277 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1278 if (!(link->flags & DL_FLAG_MANAGED))
1281 if (link->status != DL_STATE_AVAILABLE) {
1282 device_link_drop_managed(link);
1285 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
1287 dev->links.status = DL_DEV_PROBING;
1289 device_links_write_unlock();
1293 * device_links_driver_bound - Update device links after probing its driver.
1294 * @dev: Device to update the links for.
1296 * The probe has been successful, so update links from this device to any
1297 * consumers by changing their status to "available".
1299 * Also change the status of @dev's links to suppliers to "active".
1301 * Links without the DL_FLAG_MANAGED flag set are ignored.
1303 void device_links_driver_bound(struct device *dev)
1305 struct device_link *link, *ln;
1306 LIST_HEAD(sync_list);
1309 * If a device binds successfully, it's expected to have created all
1310 * the device links it needs to or make new device links as it needs
1311 * them. So, fw_devlink no longer needs to create device links to any
1312 * of the device's suppliers.
1314 * Also, if a child firmware node of this bound device is not added as a
1315 * device by now, assume it is never going to be added. Make this bound
1316 * device the fallback supplier to the dangling consumers of the child
1317 * firmware node because this bound device is probably implementing the
1318 * child firmware node functionality and we don't want the dangling
1319 * consumers to defer probe indefinitely waiting for a device for the
1320 * child firmware node.
1322 if (dev->fwnode && dev->fwnode->dev == dev) {
1323 struct fwnode_handle *child;
1324 fwnode_links_purge_suppliers(dev->fwnode);
1325 mutex_lock(&fwnode_link_lock);
1326 fwnode_for_each_available_child_node(dev->fwnode, child)
1327 __fw_devlink_pickup_dangling_consumers(child,
1329 __fw_devlink_link_to_consumers(dev);
1330 mutex_unlock(&fwnode_link_lock);
1332 device_remove_file(dev, &dev_attr_waiting_for_supplier);
1334 device_links_write_lock();
1336 list_for_each_entry(link, &dev->links.consumers, s_node) {
1337 if (!(link->flags & DL_FLAG_MANAGED))
1341 * Links created during consumer probe may be in the "consumer
1342 * probe" state to start with if the supplier is still probing
1343 * when they are created and they may become "active" if the
1344 * consumer probe returns first. Skip them here.
1346 if (link->status == DL_STATE_CONSUMER_PROBE ||
1347 link->status == DL_STATE_ACTIVE)
1350 WARN_ON(link->status != DL_STATE_DORMANT);
1351 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1353 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
1354 driver_deferred_probe_add(link->consumer);
1357 if (defer_sync_state_count)
1358 __device_links_supplier_defer_sync(dev);
1360 __device_links_queue_sync_state(dev, &sync_list);
1362 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) {
1363 struct device *supplier;
1365 if (!(link->flags & DL_FLAG_MANAGED))
1368 supplier = link->supplier;
1369 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) {
1371 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no
1372 * other DL_MANAGED_LINK_FLAGS have been set. So, it's
1373 * save to drop the managed link completely.
1375 device_link_drop_managed(link);
1376 } else if (dev_is_best_effort(dev) &&
1377 link->flags & DL_FLAG_INFERRED &&
1378 link->status != DL_STATE_CONSUMER_PROBE &&
1379 !link->supplier->can_match) {
1381 * When dev_is_best_effort() is true, we ignore device
1382 * links to suppliers that don't have a driver. If the
1383 * consumer device still managed to probe, there's no
1384 * point in maintaining a device link in a weird state
1385 * (consumer probed before supplier). So delete it.
1387 device_link_drop_managed(link);
1389 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
1390 WRITE_ONCE(link->status, DL_STATE_ACTIVE);
1394 * This needs to be done even for the deleted
1395 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last
1396 * device link that was preventing the supplier from getting a
1397 * sync_state() call.
1399 if (defer_sync_state_count)
1400 __device_links_supplier_defer_sync(supplier);
1402 __device_links_queue_sync_state(supplier, &sync_list);
1405 dev->links.status = DL_DEV_DRIVER_BOUND;
1407 device_links_write_unlock();
1409 device_links_flush_sync_list(&sync_list, dev);
1413 * __device_links_no_driver - Update links of a device without a driver.
1414 * @dev: Device without a drvier.
1416 * Delete all non-persistent links from this device to any suppliers.
1418 * Persistent links stay around, but their status is changed to "available",
1419 * unless they already are in the "supplier unbind in progress" state in which
1420 * case they need not be updated.
1422 * Links without the DL_FLAG_MANAGED flag set are ignored.
1424 static void __device_links_no_driver(struct device *dev)
1426 struct device_link *link, *ln;
1428 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1429 if (!(link->flags & DL_FLAG_MANAGED))
1432 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
1433 device_link_drop_managed(link);
1437 if (link->status != DL_STATE_CONSUMER_PROBE &&
1438 link->status != DL_STATE_ACTIVE)
1441 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) {
1442 WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
1444 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY));
1445 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1449 dev->links.status = DL_DEV_NO_DRIVER;
1453 * device_links_no_driver - Update links after failing driver probe.
1454 * @dev: Device whose driver has just failed to probe.
1456 * Clean up leftover links to consumers for @dev and invoke
1457 * %__device_links_no_driver() to update links to suppliers for it as
1460 * Links without the DL_FLAG_MANAGED flag set are ignored.
1462 void device_links_no_driver(struct device *dev)
1464 struct device_link *link;
1466 device_links_write_lock();
1468 list_for_each_entry(link, &dev->links.consumers, s_node) {
1469 if (!(link->flags & DL_FLAG_MANAGED))
1473 * The probe has failed, so if the status of the link is
1474 * "consumer probe" or "active", it must have been added by
1475 * a probing consumer while this device was still probing.
1476 * Change its state to "dormant", as it represents a valid
1477 * relationship, but it is not functionally meaningful.
1479 if (link->status == DL_STATE_CONSUMER_PROBE ||
1480 link->status == DL_STATE_ACTIVE)
1481 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1484 __device_links_no_driver(dev);
1486 device_links_write_unlock();
1490 * device_links_driver_cleanup - Update links after driver removal.
1491 * @dev: Device whose driver has just gone away.
1493 * Update links to consumers for @dev by changing their status to "dormant" and
1494 * invoke %__device_links_no_driver() to update links to suppliers for it as
1497 * Links without the DL_FLAG_MANAGED flag set are ignored.
1499 void device_links_driver_cleanup(struct device *dev)
1501 struct device_link *link, *ln;
1503 device_links_write_lock();
1505 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
1506 if (!(link->flags & DL_FLAG_MANAGED))
1509 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
1510 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
1513 * autoremove the links between this @dev and its consumer
1514 * devices that are not active, i.e. where the link state
1515 * has moved to DL_STATE_SUPPLIER_UNBIND.
1517 if (link->status == DL_STATE_SUPPLIER_UNBIND &&
1518 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
1519 device_link_drop_managed(link);
1521 WRITE_ONCE(link->status, DL_STATE_DORMANT);
1524 list_del_init(&dev->links.defer_sync);
1525 __device_links_no_driver(dev);
1527 device_links_write_unlock();
1531 * device_links_busy - Check if there are any busy links to consumers.
1532 * @dev: Device to check.
1534 * Check each consumer of the device and return 'true' if its link's status
1535 * is one of "consumer probe" or "active" (meaning that the given consumer is
1536 * probing right now or its driver is present). Otherwise, change the link
1537 * state to "supplier unbind" to prevent the consumer from being probed
1538 * successfully going forward.
1540 * Return 'false' if there are no probing or active consumers.
1542 * Links without the DL_FLAG_MANAGED flag set are ignored.
1544 bool device_links_busy(struct device *dev)
1546 struct device_link *link;
1549 device_links_write_lock();
1551 list_for_each_entry(link, &dev->links.consumers, s_node) {
1552 if (!(link->flags & DL_FLAG_MANAGED))
1555 if (link->status == DL_STATE_CONSUMER_PROBE
1556 || link->status == DL_STATE_ACTIVE) {
1560 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1563 dev->links.status = DL_DEV_UNBINDING;
1565 device_links_write_unlock();
1570 * device_links_unbind_consumers - Force unbind consumers of the given device.
1571 * @dev: Device to unbind the consumers of.
1573 * Walk the list of links to consumers for @dev and if any of them is in the
1574 * "consumer probe" state, wait for all device probes in progress to complete
1577 * If that's not the case, change the status of the link to "supplier unbind"
1578 * and check if the link was in the "active" state. If so, force the consumer
1579 * driver to unbind and start over (the consumer will not re-probe as we have
1580 * changed the state of the link already).
1582 * Links without the DL_FLAG_MANAGED flag set are ignored.
1584 void device_links_unbind_consumers(struct device *dev)
1586 struct device_link *link;
1589 device_links_write_lock();
1591 list_for_each_entry(link, &dev->links.consumers, s_node) {
1592 enum device_link_state status;
1594 if (!(link->flags & DL_FLAG_MANAGED) ||
1595 link->flags & DL_FLAG_SYNC_STATE_ONLY)
1598 status = link->status;
1599 if (status == DL_STATE_CONSUMER_PROBE) {
1600 device_links_write_unlock();
1602 wait_for_device_probe();
1605 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
1606 if (status == DL_STATE_ACTIVE) {
1607 struct device *consumer = link->consumer;
1609 get_device(consumer);
1611 device_links_write_unlock();
1613 device_release_driver_internal(consumer, NULL,
1615 put_device(consumer);
1620 device_links_write_unlock();
1624 * device_links_purge - Delete existing links to other devices.
1625 * @dev: Target device.
1627 static void device_links_purge(struct device *dev)
1629 struct device_link *link, *ln;
1631 if (dev->class == &devlink_class)
1635 * Delete all of the remaining links from this device to any other
1636 * devices (either consumers or suppliers).
1638 device_links_write_lock();
1640 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
1641 WARN_ON(link->status == DL_STATE_ACTIVE);
1642 __device_link_del(&link->kref);
1645 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
1646 WARN_ON(link->status != DL_STATE_DORMANT &&
1647 link->status != DL_STATE_NONE);
1648 __device_link_del(&link->kref);
1651 device_links_write_unlock();
1654 #define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \
1655 DL_FLAG_SYNC_STATE_ONLY)
1656 #define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \
1657 DL_FLAG_AUTOPROBE_CONSUMER)
1658 #define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \
1661 static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1662 static int __init fw_devlink_setup(char *arg)
1667 if (strcmp(arg, "off") == 0) {
1668 fw_devlink_flags = 0;
1669 } else if (strcmp(arg, "permissive") == 0) {
1670 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE;
1671 } else if (strcmp(arg, "on") == 0) {
1672 fw_devlink_flags = FW_DEVLINK_FLAGS_ON;
1673 } else if (strcmp(arg, "rpm") == 0) {
1674 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM;
1678 early_param("fw_devlink", fw_devlink_setup);
1680 static bool fw_devlink_strict;
1681 static int __init fw_devlink_strict_setup(char *arg)
1683 return kstrtobool(arg, &fw_devlink_strict);
1685 early_param("fw_devlink.strict", fw_devlink_strict_setup);
1687 #define FW_DEVLINK_SYNC_STATE_STRICT 0
1688 #define FW_DEVLINK_SYNC_STATE_TIMEOUT 1
1690 #ifndef CONFIG_FW_DEVLINK_SYNC_STATE_TIMEOUT
1691 static int fw_devlink_sync_state;
1693 static int fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1696 static int __init fw_devlink_sync_state_setup(char *arg)
1701 if (strcmp(arg, "strict") == 0) {
1702 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_STRICT;
1704 } else if (strcmp(arg, "timeout") == 0) {
1705 fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT;
1710 early_param("fw_devlink.sync_state", fw_devlink_sync_state_setup);
1712 static inline u32 fw_devlink_get_flags(u8 fwlink_flags)
1714 if (fwlink_flags & FWLINK_FLAG_CYCLE)
1715 return FW_DEVLINK_FLAGS_PERMISSIVE | DL_FLAG_CYCLE;
1717 return fw_devlink_flags;
1720 static bool fw_devlink_is_permissive(void)
1722 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE;
1725 bool fw_devlink_is_strict(void)
1727 return fw_devlink_strict && !fw_devlink_is_permissive();
1730 static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)
1732 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)
1735 fwnode_call_int_op(fwnode, add_links);
1736 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;
1739 static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
1741 struct fwnode_handle *child = NULL;
1743 fw_devlink_parse_fwnode(fwnode);
1745 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
1746 fw_devlink_parse_fwtree(child);
1749 static void fw_devlink_relax_link(struct device_link *link)
1751 if (!(link->flags & DL_FLAG_INFERRED))
1754 if (device_link_flag_is_sync_state_only(link->flags))
1757 pm_runtime_drop_link(link);
1758 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE;
1759 dev_dbg(link->consumer, "Relaxing link with %s\n",
1760 dev_name(link->supplier));
1763 static int fw_devlink_no_driver(struct device *dev, void *data)
1765 struct device_link *link = to_devlink(dev);
1767 if (!link->supplier->can_match)
1768 fw_devlink_relax_link(link);
1773 void fw_devlink_drivers_done(void)
1775 fw_devlink_drv_reg_done = true;
1776 device_links_write_lock();
1777 class_for_each_device(&devlink_class, NULL, NULL,
1778 fw_devlink_no_driver);
1779 device_links_write_unlock();
1782 static int fw_devlink_dev_sync_state(struct device *dev, void *data)
1784 struct device_link *link = to_devlink(dev);
1785 struct device *sup = link->supplier;
1787 if (!(link->flags & DL_FLAG_MANAGED) ||
1788 link->status == DL_STATE_ACTIVE || sup->state_synced ||
1789 !dev_has_sync_state(sup))
1792 if (fw_devlink_sync_state == FW_DEVLINK_SYNC_STATE_STRICT) {
1793 dev_warn(sup, "sync_state() pending due to %s\n",
1794 dev_name(link->consumer));
1798 if (!list_empty(&sup->links.defer_sync))
1801 dev_warn(sup, "Timed out. Forcing sync_state()\n");
1802 sup->state_synced = true;
1804 list_add_tail(&sup->links.defer_sync, data);
1809 void fw_devlink_probing_done(void)
1811 LIST_HEAD(sync_list);
1813 device_links_write_lock();
1814 class_for_each_device(&devlink_class, NULL, &sync_list,
1815 fw_devlink_dev_sync_state);
1816 device_links_write_unlock();
1817 device_links_flush_sync_list(&sync_list, NULL);
1821 * wait_for_init_devices_probe - Try to probe any device needed for init
1823 * Some devices might need to be probed and bound successfully before the kernel
1824 * boot sequence can finish and move on to init/userspace. For example, a
1825 * network interface might need to be bound to be able to mount a NFS rootfs.
1827 * With fw_devlink=on by default, some of these devices might be blocked from
1828 * probing because they are waiting on a optional supplier that doesn't have a
1829 * driver. While fw_devlink will eventually identify such devices and unblock
1830 * the probing automatically, it might be too late by the time it unblocks the
1831 * probing of devices. For example, the IP4 autoconfig might timeout before
1832 * fw_devlink unblocks probing of the network interface.
1834 * This function is available to temporarily try and probe all devices that have
1835 * a driver even if some of their suppliers haven't been added or don't have
1838 * The drivers can then decide which of the suppliers are optional vs mandatory
1839 * and probe the device if possible. By the time this function returns, all such
1840 * "best effort" probes are guaranteed to be completed. If a device successfully
1841 * probes in this mode, we delete all fw_devlink discovered dependencies of that
1842 * device where the supplier hasn't yet probed successfully because they have to
1843 * be optional dependencies.
1845 * Any devices that didn't successfully probe go back to being treated as if
1846 * this function was never called.
1848 * This also means that some devices that aren't needed for init and could have
1849 * waited for their optional supplier to probe (when the supplier's module is
1850 * loaded later on) would end up probing prematurely with limited functionality.
1851 * So call this function only when boot would fail without it.
1853 void __init wait_for_init_devices_probe(void)
1855 if (!fw_devlink_flags || fw_devlink_is_permissive())
1859 * Wait for all ongoing probes to finish so that the "best effort" is
1860 * only applied to devices that can't probe otherwise.
1862 wait_for_device_probe();
1864 pr_info("Trying to probe devices needed for running init ...\n");
1865 fw_devlink_best_effort = true;
1866 driver_deferred_probe_trigger();
1869 * Wait for all "best effort" probes to finish before going back to
1870 * normal enforcement.
1872 wait_for_device_probe();
1873 fw_devlink_best_effort = false;
1876 static void fw_devlink_unblock_consumers(struct device *dev)
1878 struct device_link *link;
1880 if (!fw_devlink_flags || fw_devlink_is_permissive())
1883 device_links_write_lock();
1884 list_for_each_entry(link, &dev->links.consumers, s_node)
1885 fw_devlink_relax_link(link);
1886 device_links_write_unlock();
1890 static bool fwnode_init_without_drv(struct fwnode_handle *fwnode)
1895 if (!(fwnode->flags & FWNODE_FLAG_INITIALIZED))
1898 dev = get_dev_from_fwnode(fwnode);
1899 ret = !dev || dev->links.status == DL_DEV_NO_DRIVER;
1905 static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode)
1907 struct fwnode_handle *parent;
1909 fwnode_for_each_parent_node(fwnode, parent) {
1910 if (fwnode_init_without_drv(parent)) {
1911 fwnode_handle_put(parent);
1920 * __fw_devlink_relax_cycles - Relax and mark dependency cycles.
1921 * @con: Potential consumer device.
1922 * @sup_handle: Potential supplier's fwnode.
1924 * Needs to be called with fwnode_lock and device link lock held.
1926 * Check if @sup_handle or any of its ancestors or suppliers direct/indirectly
1927 * depend on @con. This function can detect multiple cyles between @sup_handle
1928 * and @con. When such dependency cycles are found, convert all device links
1929 * created solely by fw_devlink into SYNC_STATE_ONLY device links. Also, mark
1930 * all fwnode links in the cycle with FWLINK_FLAG_CYCLE so that when they are
1931 * converted into a device link in the future, they are created as
1932 * SYNC_STATE_ONLY device links. This is the equivalent of doing
1933 * fw_devlink=permissive just between the devices in the cycle. We need to do
1934 * this because, at this point, fw_devlink can't tell which of these
1935 * dependencies is not a real dependency.
1937 * Return true if one or more cycles were found. Otherwise, return false.
1939 static bool __fw_devlink_relax_cycles(struct device *con,
1940 struct fwnode_handle *sup_handle)
1942 struct device *sup_dev = NULL, *par_dev = NULL;
1943 struct fwnode_link *link;
1944 struct device_link *dev_link;
1951 * We aren't trying to find all cycles. Just a cycle between con and
1954 if (sup_handle->flags & FWNODE_FLAG_VISITED)
1957 sup_handle->flags |= FWNODE_FLAG_VISITED;
1959 sup_dev = get_dev_from_fwnode(sup_handle);
1961 /* Termination condition. */
1962 if (sup_dev == con) {
1963 pr_debug("----- cycle: start -----\n");
1969 * If sup_dev is bound to a driver and @con hasn't started binding to a
1970 * driver, sup_dev can't be a consumer of @con. So, no need to check
1973 if (sup_dev && sup_dev->links.status == DL_DEV_DRIVER_BOUND &&
1974 con->links.status == DL_DEV_NO_DRIVER) {
1979 list_for_each_entry(link, &sup_handle->suppliers, c_hook) {
1980 if (__fw_devlink_relax_cycles(con, link->supplier)) {
1981 __fwnode_link_cycle(link);
1987 * Give priority to device parent over fwnode parent to account for any
1988 * quirks in how fwnodes are converted to devices.
1991 par_dev = get_device(sup_dev->parent);
1993 par_dev = fwnode_get_next_parent_dev(sup_handle);
1995 if (par_dev && __fw_devlink_relax_cycles(con, par_dev->fwnode)) {
1996 pr_debug("%pfwf: cycle: child of %pfwf\n", sup_handle,
2004 list_for_each_entry(dev_link, &sup_dev->links.suppliers, c_node) {
2006 * Ignore a SYNC_STATE_ONLY flag only if it wasn't marked as
2007 * such due to a cycle.
2009 if (device_link_flag_is_sync_state_only(dev_link->flags) &&
2010 !(dev_link->flags & DL_FLAG_CYCLE))
2013 if (__fw_devlink_relax_cycles(con,
2014 dev_link->supplier->fwnode)) {
2015 pr_debug("%pfwf: cycle: depends on %pfwf\n", sup_handle,
2016 dev_link->supplier->fwnode);
2017 fw_devlink_relax_link(dev_link);
2018 dev_link->flags |= DL_FLAG_CYCLE;
2024 sup_handle->flags &= ~FWNODE_FLAG_VISITED;
2025 put_device(sup_dev);
2026 put_device(par_dev);
2031 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode
2032 * @con: consumer device for the device link
2033 * @sup_handle: fwnode handle of supplier
2034 * @link: fwnode link that's being converted to a device link
2036 * This function will try to create a device link between the consumer device
2037 * @con and the supplier device represented by @sup_handle.
2039 * The supplier has to be provided as a fwnode because incorrect cycles in
2040 * fwnode links can sometimes cause the supplier device to never be created.
2041 * This function detects such cases and returns an error if it cannot create a
2042 * device link from the consumer to a missing supplier.
2045 * 0 on successfully creating a device link
2046 * -EINVAL if the device link cannot be created as expected
2047 * -EAGAIN if the device link cannot be created right now, but it may be
2048 * possible to do that in the future
2050 static int fw_devlink_create_devlink(struct device *con,
2051 struct fwnode_handle *sup_handle,
2052 struct fwnode_link *link)
2054 struct device *sup_dev;
2058 if (con->fwnode == link->consumer)
2059 flags = fw_devlink_get_flags(link->flags);
2061 flags = FW_DEVLINK_FLAGS_PERMISSIVE;
2064 * In some cases, a device P might also be a supplier to its child node
2065 * C. However, this would defer the probe of C until the probe of P
2066 * completes successfully. This is perfectly fine in the device driver
2067 * model. device_add() doesn't guarantee probe completion of the device
2068 * by the time it returns.
2070 * However, there are a few drivers that assume C will finish probing
2071 * as soon as it's added and before P finishes probing. So, we provide
2072 * a flag to let fw_devlink know not to delay the probe of C until the
2073 * probe of P completes successfully.
2075 * When such a flag is set, we can't create device links where P is the
2076 * supplier of C as that would delay the probe of C.
2078 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
2079 fwnode_is_ancestor_of(sup_handle, con->fwnode))
2083 * SYNC_STATE_ONLY device links don't block probing and supports cycles.
2084 * So, one might expect that cycle detection isn't necessary for them.
2085 * However, if the device link was marked as SYNC_STATE_ONLY because
2086 * it's part of a cycle, then we still need to do cycle detection. This
2087 * is because the consumer and supplier might be part of multiple cycles
2088 * and we need to detect all those cycles.
2090 if (!device_link_flag_is_sync_state_only(flags) ||
2091 flags & DL_FLAG_CYCLE) {
2092 device_links_write_lock();
2093 if (__fw_devlink_relax_cycles(con, sup_handle)) {
2094 __fwnode_link_cycle(link);
2095 flags = fw_devlink_get_flags(link->flags);
2096 pr_debug("----- cycle: end -----\n");
2097 dev_info(con, "Fixed dependency cycle(s) with %pfwf\n",
2100 device_links_write_unlock();
2103 if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE)
2104 sup_dev = fwnode_get_next_parent_dev(sup_handle);
2106 sup_dev = get_dev_from_fwnode(sup_handle);
2110 * If it's one of those drivers that don't actually bind to
2111 * their device using driver core, then don't wait on this
2112 * supplier device indefinitely.
2114 if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
2115 sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
2117 "Not linking %pfwf - dev might never probe\n",
2123 if (con != sup_dev && !device_link_add(con, sup_dev, flags)) {
2124 dev_err(con, "Failed to create device link (0x%x) with %s\n",
2125 flags, dev_name(sup_dev));
2133 * Supplier or supplier's ancestor already initialized without a struct
2134 * device or being probed by a driver.
2136 if (fwnode_init_without_drv(sup_handle) ||
2137 fwnode_ancestor_init_without_drv(sup_handle)) {
2138 dev_dbg(con, "Not linking %pfwf - might never become dev\n",
2145 put_device(sup_dev);
2150 * __fw_devlink_link_to_consumers - Create device links to consumers of a device
2151 * @dev: Device that needs to be linked to its consumers
2153 * This function looks at all the consumer fwnodes of @dev and creates device
2154 * links between the consumer device and @dev (supplier).
2156 * If the consumer device has not been added yet, then this function creates a
2157 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device
2158 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a
2159 * sync_state() callback before the real consumer device gets to be added and
2162 * Once device links are created from the real consumer to @dev (supplier), the
2163 * fwnode links are deleted.
2165 static void __fw_devlink_link_to_consumers(struct device *dev)
2167 struct fwnode_handle *fwnode = dev->fwnode;
2168 struct fwnode_link *link, *tmp;
2170 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
2171 struct device *con_dev;
2172 bool own_link = true;
2175 con_dev = get_dev_from_fwnode(link->consumer);
2177 * If consumer device is not available yet, make a "proxy"
2178 * SYNC_STATE_ONLY link from the consumer's parent device to
2179 * the supplier device. This is necessary to make sure the
2180 * supplier doesn't get a sync_state() callback before the real
2181 * consumer can create a device link to the supplier.
2183 * This proxy link step is needed to handle the case where the
2184 * consumer's parent device is added before the supplier.
2187 con_dev = fwnode_get_next_parent_dev(link->consumer);
2189 * However, if the consumer's parent device is also the
2190 * parent of the supplier, don't create a
2191 * consumer-supplier link from the parent to its child
2192 * device. Such a dependency is impossible.
2195 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) {
2196 put_device(con_dev);
2206 ret = fw_devlink_create_devlink(con_dev, fwnode, link);
2207 put_device(con_dev);
2208 if (!own_link || ret == -EAGAIN)
2211 __fwnode_link_del(link);
2216 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device
2217 * @dev: The consumer device that needs to be linked to its suppliers
2218 * @fwnode: Root of the fwnode tree that is used to create device links
2220 * This function looks at all the supplier fwnodes of fwnode tree rooted at
2221 * @fwnode and creates device links between @dev (consumer) and all the
2222 * supplier devices of the entire fwnode tree at @fwnode.
2224 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev
2225 * and the real suppliers of @dev. Once these device links are created, the
2226 * fwnode links are deleted.
2228 * In addition, it also looks at all the suppliers of the entire fwnode tree
2229 * because some of the child devices of @dev that have not been added yet
2230 * (because @dev hasn't probed) might already have their suppliers added to
2231 * driver core. So, this function creates SYNC_STATE_ONLY device links between
2232 * @dev (consumer) and these suppliers to make sure they don't execute their
2233 * sync_state() callbacks before these child devices have a chance to create
2234 * their device links. The fwnode links that correspond to the child devices
2235 * aren't delete because they are needed later to create the device links
2236 * between the real consumer and supplier devices.
2238 static void __fw_devlink_link_to_suppliers(struct device *dev,
2239 struct fwnode_handle *fwnode)
2241 bool own_link = (dev->fwnode == fwnode);
2242 struct fwnode_link *link, *tmp;
2243 struct fwnode_handle *child = NULL;
2245 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
2247 struct fwnode_handle *sup = link->supplier;
2249 ret = fw_devlink_create_devlink(dev, sup, link);
2250 if (!own_link || ret == -EAGAIN)
2253 __fwnode_link_del(link);
2257 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of
2258 * all the descendants. This proxy link step is needed to handle the
2259 * case where the supplier is added before the consumer's parent device
2262 while ((child = fwnode_get_next_available_child_node(fwnode, child)))
2263 __fw_devlink_link_to_suppliers(dev, child);
2266 static void fw_devlink_link_device(struct device *dev)
2268 struct fwnode_handle *fwnode = dev->fwnode;
2270 if (!fw_devlink_flags)
2273 fw_devlink_parse_fwtree(fwnode);
2275 mutex_lock(&fwnode_link_lock);
2276 __fw_devlink_link_to_consumers(dev);
2277 __fw_devlink_link_to_suppliers(dev, fwnode);
2278 mutex_unlock(&fwnode_link_lock);
2281 /* Device links support end. */
2283 int (*platform_notify)(struct device *dev) = NULL;
2284 int (*platform_notify_remove)(struct device *dev) = NULL;
2285 static struct kobject *dev_kobj;
2288 static struct kobject *sysfs_dev_char_kobj;
2290 /* /sys/dev/block */
2291 static struct kobject *sysfs_dev_block_kobj;
2293 static DEFINE_MUTEX(device_hotplug_lock);
2295 void lock_device_hotplug(void)
2297 mutex_lock(&device_hotplug_lock);
2300 void unlock_device_hotplug(void)
2302 mutex_unlock(&device_hotplug_lock);
2305 int lock_device_hotplug_sysfs(void)
2307 if (mutex_trylock(&device_hotplug_lock))
2310 /* Avoid busy looping (5 ms of sleep should do). */
2312 return restart_syscall();
2316 static inline int device_is_not_partition(struct device *dev)
2318 return !(dev->type == &part_type);
2321 static inline int device_is_not_partition(struct device *dev)
2327 static void device_platform_notify(struct device *dev)
2329 acpi_device_notify(dev);
2331 software_node_notify(dev);
2333 if (platform_notify)
2334 platform_notify(dev);
2337 static void device_platform_notify_remove(struct device *dev)
2339 if (platform_notify_remove)
2340 platform_notify_remove(dev);
2342 software_node_notify_remove(dev);
2344 acpi_device_notify_remove(dev);
2348 * dev_driver_string - Return a device's driver name, if at all possible
2349 * @dev: struct device to get the name of
2351 * Will return the device's driver's name if it is bound to a device. If
2352 * the device is not bound to a driver, it will return the name of the bus
2353 * it is attached to. If it is not attached to a bus either, an empty
2354 * string will be returned.
2356 const char *dev_driver_string(const struct device *dev)
2358 struct device_driver *drv;
2360 /* dev->driver can change to NULL underneath us because of unbinding,
2361 * so be careful about accessing it. dev->bus and dev->class should
2362 * never change once they are set, so they don't need special care.
2364 drv = READ_ONCE(dev->driver);
2365 return drv ? drv->name : dev_bus_name(dev);
2367 EXPORT_SYMBOL(dev_driver_string);
2369 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
2371 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
2374 struct device_attribute *dev_attr = to_dev_attr(attr);
2375 struct device *dev = kobj_to_dev(kobj);
2379 ret = dev_attr->show(dev, dev_attr, buf);
2380 if (ret >= (ssize_t)PAGE_SIZE) {
2381 printk("dev_attr_show: %pS returned bad count\n",
2387 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
2388 const char *buf, size_t count)
2390 struct device_attribute *dev_attr = to_dev_attr(attr);
2391 struct device *dev = kobj_to_dev(kobj);
2394 if (dev_attr->store)
2395 ret = dev_attr->store(dev, dev_attr, buf, count);
2399 static const struct sysfs_ops dev_sysfs_ops = {
2400 .show = dev_attr_show,
2401 .store = dev_attr_store,
2404 #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
2406 ssize_t device_store_ulong(struct device *dev,
2407 struct device_attribute *attr,
2408 const char *buf, size_t size)
2410 struct dev_ext_attribute *ea = to_ext_attr(attr);
2414 ret = kstrtoul(buf, 0, &new);
2417 *(unsigned long *)(ea->var) = new;
2418 /* Always return full write size even if we didn't consume all */
2421 EXPORT_SYMBOL_GPL(device_store_ulong);
2423 ssize_t device_show_ulong(struct device *dev,
2424 struct device_attribute *attr,
2427 struct dev_ext_attribute *ea = to_ext_attr(attr);
2428 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
2430 EXPORT_SYMBOL_GPL(device_show_ulong);
2432 ssize_t device_store_int(struct device *dev,
2433 struct device_attribute *attr,
2434 const char *buf, size_t size)
2436 struct dev_ext_attribute *ea = to_ext_attr(attr);
2440 ret = kstrtol(buf, 0, &new);
2444 if (new > INT_MAX || new < INT_MIN)
2446 *(int *)(ea->var) = new;
2447 /* Always return full write size even if we didn't consume all */
2450 EXPORT_SYMBOL_GPL(device_store_int);
2452 ssize_t device_show_int(struct device *dev,
2453 struct device_attribute *attr,
2456 struct dev_ext_attribute *ea = to_ext_attr(attr);
2458 return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
2460 EXPORT_SYMBOL_GPL(device_show_int);
2462 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
2463 const char *buf, size_t size)
2465 struct dev_ext_attribute *ea = to_ext_attr(attr);
2467 if (kstrtobool(buf, ea->var) < 0)
2472 EXPORT_SYMBOL_GPL(device_store_bool);
2474 ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
2477 struct dev_ext_attribute *ea = to_ext_attr(attr);
2479 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
2481 EXPORT_SYMBOL_GPL(device_show_bool);
2484 * device_release - free device structure.
2485 * @kobj: device's kobject.
2487 * This is called once the reference count for the object
2488 * reaches 0. We forward the call to the device's release
2489 * method, which should handle actually freeing the structure.
2491 static void device_release(struct kobject *kobj)
2493 struct device *dev = kobj_to_dev(kobj);
2494 struct device_private *p = dev->p;
2497 * Some platform devices are driven without driver attached
2498 * and managed resources may have been acquired. Make sure
2499 * all resources are released.
2501 * Drivers still can add resources into device after device
2502 * is deleted but alive, so release devres here to avoid
2503 * possible memory leak.
2505 devres_release_all(dev);
2507 kfree(dev->dma_range_map);
2511 else if (dev->type && dev->type->release)
2512 dev->type->release(dev);
2513 else if (dev->class && dev->class->dev_release)
2514 dev->class->dev_release(dev);
2516 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",
2521 static const void *device_namespace(const struct kobject *kobj)
2523 const struct device *dev = kobj_to_dev(kobj);
2524 const void *ns = NULL;
2526 if (dev->class && dev->class->ns_type)
2527 ns = dev->class->namespace(dev);
2532 static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid)
2534 const struct device *dev = kobj_to_dev(kobj);
2536 if (dev->class && dev->class->get_ownership)
2537 dev->class->get_ownership(dev, uid, gid);
2540 static const struct kobj_type device_ktype = {
2541 .release = device_release,
2542 .sysfs_ops = &dev_sysfs_ops,
2543 .namespace = device_namespace,
2544 .get_ownership = device_get_ownership,
2548 static int dev_uevent_filter(const struct kobject *kobj)
2550 const struct kobj_type *ktype = get_ktype(kobj);
2552 if (ktype == &device_ktype) {
2553 const struct device *dev = kobj_to_dev(kobj);
2562 static const char *dev_uevent_name(const struct kobject *kobj)
2564 const struct device *dev = kobj_to_dev(kobj);
2567 return dev->bus->name;
2569 return dev->class->name;
2573 static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env)
2575 const struct device *dev = kobj_to_dev(kobj);
2578 /* add device node properties if present */
2579 if (MAJOR(dev->devt)) {
2583 kuid_t uid = GLOBAL_ROOT_UID;
2584 kgid_t gid = GLOBAL_ROOT_GID;
2586 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
2587 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
2588 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
2590 add_uevent_var(env, "DEVNAME=%s", name);
2592 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
2593 if (!uid_eq(uid, GLOBAL_ROOT_UID))
2594 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
2595 if (!gid_eq(gid, GLOBAL_ROOT_GID))
2596 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
2601 if (dev->type && dev->type->name)
2602 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
2605 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
2607 /* Add common DT information about the device */
2608 of_device_uevent(dev, env);
2610 /* have the bus specific function add its stuff */
2611 if (dev->bus && dev->bus->uevent) {
2612 retval = dev->bus->uevent(dev, env);
2614 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
2615 dev_name(dev), __func__, retval);
2618 /* have the class specific function add its stuff */
2619 if (dev->class && dev->class->dev_uevent) {
2620 retval = dev->class->dev_uevent(dev, env);
2622 pr_debug("device: '%s': %s: class uevent() "
2623 "returned %d\n", dev_name(dev),
2627 /* have the device type specific function add its stuff */
2628 if (dev->type && dev->type->uevent) {
2629 retval = dev->type->uevent(dev, env);
2631 pr_debug("device: '%s': %s: dev_type uevent() "
2632 "returned %d\n", dev_name(dev),
2639 static const struct kset_uevent_ops device_uevent_ops = {
2640 .filter = dev_uevent_filter,
2641 .name = dev_uevent_name,
2642 .uevent = dev_uevent,
2645 static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
2648 struct kobject *top_kobj;
2650 struct kobj_uevent_env *env = NULL;
2655 /* search the kset, the device belongs to */
2656 top_kobj = &dev->kobj;
2657 while (!top_kobj->kset && top_kobj->parent)
2658 top_kobj = top_kobj->parent;
2659 if (!top_kobj->kset)
2662 kset = top_kobj->kset;
2663 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
2666 /* respect filter */
2667 if (kset->uevent_ops && kset->uevent_ops->filter)
2668 if (!kset->uevent_ops->filter(&dev->kobj))
2671 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
2675 /* let the kset specific function add its keys */
2676 retval = kset->uevent_ops->uevent(&dev->kobj, env);
2680 /* copy keys to file */
2681 for (i = 0; i < env->envp_idx; i++)
2682 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]);
2688 static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
2689 const char *buf, size_t count)
2693 rc = kobject_synth_uevent(&dev->kobj, buf, count);
2696 dev_err(dev, "uevent: failed to send synthetic uevent: %d\n", rc);
2702 static DEVICE_ATTR_RW(uevent);
2704 static ssize_t online_show(struct device *dev, struct device_attribute *attr,
2710 val = !dev->offline;
2712 return sysfs_emit(buf, "%u\n", val);
2715 static ssize_t online_store(struct device *dev, struct device_attribute *attr,
2716 const char *buf, size_t count)
2721 ret = kstrtobool(buf, &val);
2725 ret = lock_device_hotplug_sysfs();
2729 ret = val ? device_online(dev) : device_offline(dev);
2730 unlock_device_hotplug();
2731 return ret < 0 ? ret : count;
2733 static DEVICE_ATTR_RW(online);
2735 static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
2740 switch (dev->removable) {
2741 case DEVICE_REMOVABLE:
2750 return sysfs_emit(buf, "%s\n", loc);
2752 static DEVICE_ATTR_RO(removable);
2754 int device_add_groups(struct device *dev, const struct attribute_group **groups)
2756 return sysfs_create_groups(&dev->kobj, groups);
2758 EXPORT_SYMBOL_GPL(device_add_groups);
2760 void device_remove_groups(struct device *dev,
2761 const struct attribute_group **groups)
2763 sysfs_remove_groups(&dev->kobj, groups);
2765 EXPORT_SYMBOL_GPL(device_remove_groups);
2767 union device_attr_group_devres {
2768 const struct attribute_group *group;
2769 const struct attribute_group **groups;
2772 static void devm_attr_group_remove(struct device *dev, void *res)
2774 union device_attr_group_devres *devres = res;
2775 const struct attribute_group *group = devres->group;
2777 dev_dbg(dev, "%s: removing group %p\n", __func__, group);
2778 sysfs_remove_group(&dev->kobj, group);
2781 static void devm_attr_groups_remove(struct device *dev, void *res)
2783 union device_attr_group_devres *devres = res;
2784 const struct attribute_group **groups = devres->groups;
2786 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
2787 sysfs_remove_groups(&dev->kobj, groups);
2791 * devm_device_add_group - given a device, create a managed attribute group
2792 * @dev: The device to create the group for
2793 * @grp: The attribute group to create
2795 * This function creates a group for the first time. It will explicitly
2796 * warn and error if any of the attribute files being created already exist.
2798 * Returns 0 on success or error code on failure.
2800 int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
2802 union device_attr_group_devres *devres;
2805 devres = devres_alloc(devm_attr_group_remove,
2806 sizeof(*devres), GFP_KERNEL);
2810 error = sysfs_create_group(&dev->kobj, grp);
2812 devres_free(devres);
2816 devres->group = grp;
2817 devres_add(dev, devres);
2820 EXPORT_SYMBOL_GPL(devm_device_add_group);
2823 * devm_device_add_groups - create a bunch of managed attribute groups
2824 * @dev: The device to create the group for
2825 * @groups: The attribute groups to create, NULL terminated
2827 * This function creates a bunch of managed attribute groups. If an error
2828 * occurs when creating a group, all previously created groups will be
2829 * removed, unwinding everything back to the original state when this
2830 * function was called. It will explicitly warn and error if any of the
2831 * attribute files being created already exist.
2833 * Returns 0 on success or error code from sysfs_create_group on failure.
2835 int devm_device_add_groups(struct device *dev,
2836 const struct attribute_group **groups)
2838 union device_attr_group_devres *devres;
2841 devres = devres_alloc(devm_attr_groups_remove,
2842 sizeof(*devres), GFP_KERNEL);
2846 error = sysfs_create_groups(&dev->kobj, groups);
2848 devres_free(devres);
2852 devres->groups = groups;
2853 devres_add(dev, devres);
2856 EXPORT_SYMBOL_GPL(devm_device_add_groups);
2858 static int device_add_attrs(struct device *dev)
2860 const struct class *class = dev->class;
2861 const struct device_type *type = dev->type;
2865 error = device_add_groups(dev, class->dev_groups);
2871 error = device_add_groups(dev, type->groups);
2873 goto err_remove_class_groups;
2876 error = device_add_groups(dev, dev->groups);
2878 goto err_remove_type_groups;
2880 if (device_supports_offline(dev) && !dev->offline_disabled) {
2881 error = device_create_file(dev, &dev_attr_online);
2883 goto err_remove_dev_groups;
2886 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) {
2887 error = device_create_file(dev, &dev_attr_waiting_for_supplier);
2889 goto err_remove_dev_online;
2892 if (dev_removable_is_valid(dev)) {
2893 error = device_create_file(dev, &dev_attr_removable);
2895 goto err_remove_dev_waiting_for_supplier;
2898 if (dev_add_physical_location(dev)) {
2899 error = device_add_group(dev,
2900 &dev_attr_physical_location_group);
2902 goto err_remove_dev_removable;
2907 err_remove_dev_removable:
2908 device_remove_file(dev, &dev_attr_removable);
2909 err_remove_dev_waiting_for_supplier:
2910 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2911 err_remove_dev_online:
2912 device_remove_file(dev, &dev_attr_online);
2913 err_remove_dev_groups:
2914 device_remove_groups(dev, dev->groups);
2915 err_remove_type_groups:
2917 device_remove_groups(dev, type->groups);
2918 err_remove_class_groups:
2920 device_remove_groups(dev, class->dev_groups);
2925 static void device_remove_attrs(struct device *dev)
2927 const struct class *class = dev->class;
2928 const struct device_type *type = dev->type;
2930 if (dev->physical_location) {
2931 device_remove_group(dev, &dev_attr_physical_location_group);
2932 kfree(dev->physical_location);
2935 device_remove_file(dev, &dev_attr_removable);
2936 device_remove_file(dev, &dev_attr_waiting_for_supplier);
2937 device_remove_file(dev, &dev_attr_online);
2938 device_remove_groups(dev, dev->groups);
2941 device_remove_groups(dev, type->groups);
2944 device_remove_groups(dev, class->dev_groups);
2947 static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
2950 return print_dev_t(buf, dev->devt);
2952 static DEVICE_ATTR_RO(dev);
2955 struct kset *devices_kset;
2958 * devices_kset_move_before - Move device in the devices_kset's list.
2959 * @deva: Device to move.
2960 * @devb: Device @deva should come before.
2962 static void devices_kset_move_before(struct device *deva, struct device *devb)
2966 pr_debug("devices_kset: Moving %s before %s\n",
2967 dev_name(deva), dev_name(devb));
2968 spin_lock(&devices_kset->list_lock);
2969 list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
2970 spin_unlock(&devices_kset->list_lock);
2974 * devices_kset_move_after - Move device in the devices_kset's list.
2975 * @deva: Device to move
2976 * @devb: Device @deva should come after.
2978 static void devices_kset_move_after(struct device *deva, struct device *devb)
2982 pr_debug("devices_kset: Moving %s after %s\n",
2983 dev_name(deva), dev_name(devb));
2984 spin_lock(&devices_kset->list_lock);
2985 list_move(&deva->kobj.entry, &devb->kobj.entry);
2986 spin_unlock(&devices_kset->list_lock);
2990 * devices_kset_move_last - move the device to the end of devices_kset's list.
2991 * @dev: device to move
2993 void devices_kset_move_last(struct device *dev)
2997 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
2998 spin_lock(&devices_kset->list_lock);
2999 list_move_tail(&dev->kobj.entry, &devices_kset->list);
3000 spin_unlock(&devices_kset->list_lock);
3004 * device_create_file - create sysfs attribute file for device.
3006 * @attr: device attribute descriptor.
3008 int device_create_file(struct device *dev,
3009 const struct device_attribute *attr)
3014 WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
3015 "Attribute %s: write permission without 'store'\n",
3017 WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
3018 "Attribute %s: read permission without 'show'\n",
3020 error = sysfs_create_file(&dev->kobj, &attr->attr);
3025 EXPORT_SYMBOL_GPL(device_create_file);
3028 * device_remove_file - remove sysfs attribute file.
3030 * @attr: device attribute descriptor.
3032 void device_remove_file(struct device *dev,
3033 const struct device_attribute *attr)
3036 sysfs_remove_file(&dev->kobj, &attr->attr);
3038 EXPORT_SYMBOL_GPL(device_remove_file);
3041 * device_remove_file_self - remove sysfs attribute file from its own method.
3043 * @attr: device attribute descriptor.
3045 * See kernfs_remove_self() for details.
3047 bool device_remove_file_self(struct device *dev,
3048 const struct device_attribute *attr)
3051 return sysfs_remove_file_self(&dev->kobj, &attr->attr);
3055 EXPORT_SYMBOL_GPL(device_remove_file_self);
3058 * device_create_bin_file - create sysfs binary attribute file for device.
3060 * @attr: device binary attribute descriptor.
3062 int device_create_bin_file(struct device *dev,
3063 const struct bin_attribute *attr)
3065 int error = -EINVAL;
3067 error = sysfs_create_bin_file(&dev->kobj, attr);
3070 EXPORT_SYMBOL_GPL(device_create_bin_file);
3073 * device_remove_bin_file - remove sysfs binary attribute file
3075 * @attr: device binary attribute descriptor.
3077 void device_remove_bin_file(struct device *dev,
3078 const struct bin_attribute *attr)
3081 sysfs_remove_bin_file(&dev->kobj, attr);
3083 EXPORT_SYMBOL_GPL(device_remove_bin_file);
3085 static void klist_children_get(struct klist_node *n)
3087 struct device_private *p = to_device_private_parent(n);
3088 struct device *dev = p->device;
3093 static void klist_children_put(struct klist_node *n)
3095 struct device_private *p = to_device_private_parent(n);
3096 struct device *dev = p->device;
3102 * device_initialize - init device structure.
3105 * This prepares the device for use by other layers by initializing
3107 * It is the first half of device_register(), if called by
3108 * that function, though it can also be called separately, so one
3109 * may use @dev's fields. In particular, get_device()/put_device()
3110 * may be used for reference counting of @dev after calling this
3113 * All fields in @dev must be initialized by the caller to 0, except
3114 * for those explicitly set to some other value. The simplest
3115 * approach is to use kzalloc() to allocate the structure containing
3118 * NOTE: Use put_device() to give up your reference instead of freeing
3119 * @dev directly once you have called this function.
3121 void device_initialize(struct device *dev)
3123 dev->kobj.kset = devices_kset;
3124 kobject_init(&dev->kobj, &device_ktype);
3125 INIT_LIST_HEAD(&dev->dma_pools);
3126 mutex_init(&dev->mutex);
3127 lockdep_set_novalidate_class(&dev->mutex);
3128 spin_lock_init(&dev->devres_lock);
3129 INIT_LIST_HEAD(&dev->devres_head);
3130 device_pm_init(dev);
3131 set_dev_node(dev, NUMA_NO_NODE);
3132 INIT_LIST_HEAD(&dev->links.consumers);
3133 INIT_LIST_HEAD(&dev->links.suppliers);
3134 INIT_LIST_HEAD(&dev->links.defer_sync);
3135 dev->links.status = DL_DEV_NO_DRIVER;
3136 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
3137 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
3138 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
3139 dev->dma_coherent = dma_default_coherent;
3141 swiotlb_dev_init(dev);
3143 EXPORT_SYMBOL_GPL(device_initialize);
3145 struct kobject *virtual_device_parent(struct device *dev)
3147 static struct kobject *virtual_dir = NULL;
3150 virtual_dir = kobject_create_and_add("virtual",
3151 &devices_kset->kobj);
3157 struct kobject kobj;
3158 const struct class *class;
3161 #define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
3163 static void class_dir_release(struct kobject *kobj)
3165 struct class_dir *dir = to_class_dir(kobj);
3170 struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *kobj)
3172 const struct class_dir *dir = to_class_dir(kobj);
3173 return dir->class->ns_type;
3176 static const struct kobj_type class_dir_ktype = {
3177 .release = class_dir_release,
3178 .sysfs_ops = &kobj_sysfs_ops,
3179 .child_ns_type = class_dir_child_ns_type
3182 static struct kobject *class_dir_create_and_add(struct subsys_private *sp,
3183 struct kobject *parent_kobj)
3185 struct class_dir *dir;
3188 dir = kzalloc(sizeof(*dir), GFP_KERNEL);
3190 return ERR_PTR(-ENOMEM);
3192 dir->class = sp->class;
3193 kobject_init(&dir->kobj, &class_dir_ktype);
3195 dir->kobj.kset = &sp->glue_dirs;
3197 retval = kobject_add(&dir->kobj, parent_kobj, "%s", sp->class->name);
3199 kobject_put(&dir->kobj);
3200 return ERR_PTR(retval);
3205 static DEFINE_MUTEX(gdp_mutex);
3207 static struct kobject *get_device_parent(struct device *dev,
3208 struct device *parent)
3210 struct subsys_private *sp = class_to_subsys(dev->class);
3211 struct kobject *kobj = NULL;
3214 struct kobject *parent_kobj;
3218 * If we have no parent, we live in "virtual".
3219 * Class-devices with a non class-device as parent, live
3220 * in a "glue" directory to prevent namespace collisions.
3223 parent_kobj = virtual_device_parent(dev);
3224 else if (parent->class && !dev->class->ns_type) {
3226 return &parent->kobj;
3228 parent_kobj = &parent->kobj;
3231 mutex_lock(&gdp_mutex);
3233 /* find our class-directory at the parent and reference it */
3234 spin_lock(&sp->glue_dirs.list_lock);
3235 list_for_each_entry(k, &sp->glue_dirs.list, entry)
3236 if (k->parent == parent_kobj) {
3237 kobj = kobject_get(k);
3240 spin_unlock(&sp->glue_dirs.list_lock);
3242 mutex_unlock(&gdp_mutex);
3247 /* or create a new class-directory at the parent device */
3248 k = class_dir_create_and_add(sp, parent_kobj);
3249 /* do not emit an uevent for this simple "glue" directory */
3250 mutex_unlock(&gdp_mutex);
3255 /* subsystems can specify a default root directory for their devices */
3256 if (!parent && dev->bus) {
3257 struct device *dev_root = bus_get_dev_root(dev->bus);
3260 kobj = &dev_root->kobj;
3261 put_device(dev_root);
3267 return &parent->kobj;
3271 static inline bool live_in_glue_dir(struct kobject *kobj,
3274 struct subsys_private *sp;
3277 if (!kobj || !dev->class)
3280 sp = class_to_subsys(dev->class);
3284 if (kobj->kset == &sp->glue_dirs)
3293 static inline struct kobject *get_glue_dir(struct device *dev)
3295 return dev->kobj.parent;
3299 * kobject_has_children - Returns whether a kobject has children.
3300 * @kobj: the object to test
3302 * This will return whether a kobject has other kobjects as children.
3304 * It does NOT account for the presence of attribute files, only sub
3305 * directories. It also assumes there is no concurrent addition or
3306 * removal of such children, and thus relies on external locking.
3308 static inline bool kobject_has_children(struct kobject *kobj)
3310 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
3312 return kobj->sd && kobj->sd->dir.subdirs;
3316 * make sure cleaning up dir as the last step, we need to make
3317 * sure .release handler of kobject is run with holding the
3320 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
3324 /* see if we live in a "glue" directory */
3325 if (!live_in_glue_dir(glue_dir, dev))
3328 mutex_lock(&gdp_mutex);
3330 * There is a race condition between removing glue directory
3331 * and adding a new device under the glue directory.
3336 * get_device_parent()
3337 * class_dir_create_and_add()
3338 * kobject_add_internal()
3339 * create_dir() // create glue_dir
3342 * get_device_parent()
3343 * kobject_get() // get glue_dir
3346 * cleanup_glue_dir()
3347 * kobject_del(glue_dir)
3350 * kobject_add_internal()
3351 * create_dir() // in glue_dir
3352 * sysfs_create_dir_ns()
3353 * kernfs_create_dir_ns(sd)
3355 * sysfs_remove_dir() // glue_dir->sd=NULL
3356 * sysfs_put() // free glue_dir->sd
3359 * kernfs_new_node(sd)
3360 * kernfs_get(glue_dir)
3364 * Before CPU1 remove last child device under glue dir, if CPU2 add
3365 * a new device under glue dir, the glue_dir kobject reference count
3366 * will be increase to 2 in kobject_get(k). And CPU2 has been called
3367 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
3368 * and sysfs_put(). This result in glue_dir->sd is freed.
3370 * Then the CPU2 will see a stale "empty" but still potentially used
3371 * glue dir around in kernfs_new_node().
3373 * In order to avoid this happening, we also should make sure that
3374 * kernfs_node for glue_dir is released in CPU1 only when refcount
3375 * for glue_dir kobj is 1.
3377 ref = kref_read(&glue_dir->kref);
3378 if (!kobject_has_children(glue_dir) && !--ref)
3379 kobject_del(glue_dir);
3380 kobject_put(glue_dir);
3381 mutex_unlock(&gdp_mutex);
3384 static int device_add_class_symlinks(struct device *dev)
3386 struct device_node *of_node = dev_of_node(dev);
3387 struct subsys_private *sp;
3391 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
3393 dev_warn(dev, "Error %d creating of_node link\n",error);
3394 /* An error here doesn't warrant bringing down the device */
3397 sp = class_to_subsys(dev->class);
3401 error = sysfs_create_link(&dev->kobj, &sp->subsys.kobj, "subsystem");
3405 if (dev->parent && device_is_not_partition(dev)) {
3406 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
3412 /* link in the class directory pointing to the device */
3413 error = sysfs_create_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3419 sysfs_remove_link(&dev->kobj, "device");
3421 sysfs_remove_link(&dev->kobj, "subsystem");
3423 sysfs_remove_link(&dev->kobj, "of_node");
3429 static void device_remove_class_symlinks(struct device *dev)
3431 struct subsys_private *sp = class_to_subsys(dev->class);
3433 if (dev_of_node(dev))
3434 sysfs_remove_link(&dev->kobj, "of_node");
3439 if (dev->parent && device_is_not_partition(dev))
3440 sysfs_remove_link(&dev->kobj, "device");
3441 sysfs_remove_link(&dev->kobj, "subsystem");
3442 sysfs_delete_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev));
3447 * dev_set_name - set a device name
3449 * @fmt: format string for the device's name
3451 int dev_set_name(struct device *dev, const char *fmt, ...)
3456 va_start(vargs, fmt);
3457 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
3461 EXPORT_SYMBOL_GPL(dev_set_name);
3463 /* select a /sys/dev/ directory for the device */
3464 static struct kobject *device_to_dev_kobj(struct device *dev)
3466 if (is_blockdev(dev))
3467 return sysfs_dev_block_kobj;
3469 return sysfs_dev_char_kobj;
3472 static int device_create_sys_dev_entry(struct device *dev)
3474 struct kobject *kobj = device_to_dev_kobj(dev);
3479 format_dev_t(devt_str, dev->devt);
3480 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
3486 static void device_remove_sys_dev_entry(struct device *dev)
3488 struct kobject *kobj = device_to_dev_kobj(dev);
3492 format_dev_t(devt_str, dev->devt);
3493 sysfs_remove_link(kobj, devt_str);
3497 static int device_private_init(struct device *dev)
3499 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
3502 dev->p->device = dev;
3503 klist_init(&dev->p->klist_children, klist_children_get,
3504 klist_children_put);
3505 INIT_LIST_HEAD(&dev->p->deferred_probe);
3510 * device_add - add device to device hierarchy.
3513 * This is part 2 of device_register(), though may be called
3514 * separately _iff_ device_initialize() has been called separately.
3516 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
3517 * to the global and sibling lists for the device, then
3518 * adds it to the other relevant subsystems of the driver model.
3520 * Do not call this routine or device_register() more than once for
3521 * any device structure. The driver model core is not designed to work
3522 * with devices that get unregistered and then spring back to life.
3523 * (Among other things, it's very hard to guarantee that all references
3524 * to the previous incarnation of @dev have been dropped.) Allocate
3525 * and register a fresh new struct device instead.
3527 * NOTE: _Never_ directly free @dev after calling this function, even
3528 * if it returned an error! Always use put_device() to give up your
3529 * reference instead.
3531 * Rule of thumb is: if device_add() succeeds, you should call
3532 * device_del() when you want to get rid of it. If device_add() has
3533 * *not* succeeded, use *only* put_device() to drop the reference
3536 int device_add(struct device *dev)
3538 struct subsys_private *sp;
3539 struct device *parent;
3540 struct kobject *kobj;
3541 struct class_interface *class_intf;
3542 int error = -EINVAL;
3543 struct kobject *glue_dir = NULL;
3545 dev = get_device(dev);
3550 error = device_private_init(dev);
3556 * for statically allocated devices, which should all be converted
3557 * some day, we need to initialize the name. We prevent reading back
3558 * the name, and force the use of dev_name()
3560 if (dev->init_name) {
3561 error = dev_set_name(dev, "%s", dev->init_name);
3562 dev->init_name = NULL;
3567 /* subsystems can specify simple device enumeration */
3568 else if (dev->bus && dev->bus->dev_name)
3569 error = dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
3575 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3577 parent = get_device(dev->parent);
3578 kobj = get_device_parent(dev, parent);
3580 error = PTR_ERR(kobj);
3584 dev->kobj.parent = kobj;
3586 /* use parent numa_node */
3587 if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
3588 set_dev_node(dev, dev_to_node(parent));
3590 /* first, register with generic layer. */
3591 /* we require the name to be set before, and pass NULL */
3592 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
3598 /* notify platform of device entry */
3599 device_platform_notify(dev);
3601 error = device_create_file(dev, &dev_attr_uevent);
3605 error = device_add_class_symlinks(dev);
3608 error = device_add_attrs(dev);
3611 error = bus_add_device(dev);
3614 error = dpm_sysfs_add(dev);
3619 if (MAJOR(dev->devt)) {
3620 error = device_create_file(dev, &dev_attr_dev);
3624 error = device_create_sys_dev_entry(dev);
3628 devtmpfs_create_node(dev);
3631 /* Notify clients of device addition. This call must come
3632 * after dpm_sysfs_add() and before kobject_uevent().
3634 bus_notify(dev, BUS_NOTIFY_ADD_DEVICE);
3635 kobject_uevent(&dev->kobj, KOBJ_ADD);
3638 * Check if any of the other devices (consumers) have been waiting for
3639 * this device (supplier) to be added so that they can create a device
3642 * This needs to happen after device_pm_add() because device_link_add()
3643 * requires the supplier be registered before it's called.
3645 * But this also needs to happen before bus_probe_device() to make sure
3646 * waiting consumers can link to it before the driver is bound to the
3647 * device and the driver sync_state callback is called for this device.
3649 if (dev->fwnode && !dev->fwnode->dev) {
3650 dev->fwnode->dev = dev;
3651 fw_devlink_link_device(dev);
3654 bus_probe_device(dev);
3657 * If all driver registration is done and a newly added device doesn't
3658 * match with any driver, don't block its consumers from probing in
3659 * case the consumer device is able to operate without this supplier.
3661 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match)
3662 fw_devlink_unblock_consumers(dev);
3665 klist_add_tail(&dev->p->knode_parent,
3666 &parent->p->klist_children);
3668 sp = class_to_subsys(dev->class);
3670 mutex_lock(&sp->mutex);
3671 /* tie the class to the device */
3672 klist_add_tail(&dev->p->knode_class, &sp->klist_devices);
3674 /* notify any interfaces that the device is here */
3675 list_for_each_entry(class_intf, &sp->interfaces, node)
3676 if (class_intf->add_dev)
3677 class_intf->add_dev(dev);
3678 mutex_unlock(&sp->mutex);
3685 if (MAJOR(dev->devt))
3686 device_remove_file(dev, &dev_attr_dev);
3688 device_pm_remove(dev);
3689 dpm_sysfs_remove(dev);
3692 bus_remove_device(dev);
3694 device_remove_attrs(dev);
3696 device_remove_class_symlinks(dev);
3698 device_remove_file(dev, &dev_attr_uevent);
3700 device_platform_notify_remove(dev);
3701 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3702 glue_dir = get_glue_dir(dev);
3703 kobject_del(&dev->kobj);
3705 cleanup_glue_dir(dev, glue_dir);
3713 EXPORT_SYMBOL_GPL(device_add);
3716 * device_register - register a device with the system.
3717 * @dev: pointer to the device structure
3719 * This happens in two clean steps - initialize the device
3720 * and add it to the system. The two steps can be called
3721 * separately, but this is the easiest and most common.
3722 * I.e. you should only call the two helpers separately if
3723 * have a clearly defined need to use and refcount the device
3724 * before it is added to the hierarchy.
3726 * For more information, see the kerneldoc for device_initialize()
3729 * NOTE: _Never_ directly free @dev after calling this function, even
3730 * if it returned an error! Always use put_device() to give up the
3731 * reference initialized in this function instead.
3733 int device_register(struct device *dev)
3735 device_initialize(dev);
3736 return device_add(dev);
3738 EXPORT_SYMBOL_GPL(device_register);
3741 * get_device - increment reference count for device.
3744 * This simply forwards the call to kobject_get(), though
3745 * we do take care to provide for the case that we get a NULL
3746 * pointer passed in.
3748 struct device *get_device(struct device *dev)
3750 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
3752 EXPORT_SYMBOL_GPL(get_device);
3755 * put_device - decrement reference count.
3756 * @dev: device in question.
3758 void put_device(struct device *dev)
3760 /* might_sleep(); */
3762 kobject_put(&dev->kobj);
3764 EXPORT_SYMBOL_GPL(put_device);
3766 bool kill_device(struct device *dev)
3769 * Require the device lock and set the "dead" flag to guarantee that
3770 * the update behavior is consistent with the other bitfields near
3771 * it and that we cannot have an asynchronous probe routine trying
3772 * to run while we are tearing out the bus/class/sysfs from
3773 * underneath the device.
3775 device_lock_assert(dev);
3779 dev->p->dead = true;
3782 EXPORT_SYMBOL_GPL(kill_device);
3785 * device_del - delete device from system.
3788 * This is the first part of the device unregistration
3789 * sequence. This removes the device from the lists we control
3790 * from here, has it removed from the other driver model
3791 * subsystems it was added to in device_add(), and removes it
3792 * from the kobject hierarchy.
3794 * NOTE: this should be called manually _iff_ device_add() was
3795 * also called manually.
3797 void device_del(struct device *dev)
3799 struct subsys_private *sp;
3800 struct device *parent = dev->parent;
3801 struct kobject *glue_dir = NULL;
3802 struct class_interface *class_intf;
3803 unsigned int noio_flag;
3809 if (dev->fwnode && dev->fwnode->dev == dev)
3810 dev->fwnode->dev = NULL;
3812 /* Notify clients of device removal. This call must come
3813 * before dpm_sysfs_remove().
3815 noio_flag = memalloc_noio_save();
3816 bus_notify(dev, BUS_NOTIFY_DEL_DEVICE);
3818 dpm_sysfs_remove(dev);
3820 klist_del(&dev->p->knode_parent);
3821 if (MAJOR(dev->devt)) {
3822 devtmpfs_delete_node(dev);
3823 device_remove_sys_dev_entry(dev);
3824 device_remove_file(dev, &dev_attr_dev);
3827 sp = class_to_subsys(dev->class);
3829 device_remove_class_symlinks(dev);
3831 mutex_lock(&sp->mutex);
3832 /* notify any interfaces that the device is now gone */
3833 list_for_each_entry(class_intf, &sp->interfaces, node)
3834 if (class_intf->remove_dev)
3835 class_intf->remove_dev(dev);
3836 /* remove the device from the class list */
3837 klist_del(&dev->p->knode_class);
3838 mutex_unlock(&sp->mutex);
3841 device_remove_file(dev, &dev_attr_uevent);
3842 device_remove_attrs(dev);
3843 bus_remove_device(dev);
3844 device_pm_remove(dev);
3845 driver_deferred_probe_del(dev);
3846 device_platform_notify_remove(dev);
3847 device_links_purge(dev);
3850 * If a device does not have a driver attached, we need to clean
3851 * up any managed resources. We do this in device_release(), but
3852 * it's never called (and we leak the device) if a managed
3853 * resource holds a reference to the device. So release all
3854 * managed resources here, like we do in driver_detach(). We
3855 * still need to do so again in device_release() in case someone
3856 * adds a new resource after this point, though.
3858 devres_release_all(dev);
3860 bus_notify(dev, BUS_NOTIFY_REMOVED_DEVICE);
3861 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
3862 glue_dir = get_glue_dir(dev);
3863 kobject_del(&dev->kobj);
3864 cleanup_glue_dir(dev, glue_dir);
3865 memalloc_noio_restore(noio_flag);
3868 EXPORT_SYMBOL_GPL(device_del);
3871 * device_unregister - unregister device from system.
3872 * @dev: device going away.
3874 * We do this in two parts, like we do device_register(). First,
3875 * we remove it from all the subsystems with device_del(), then
3876 * we decrement the reference count via put_device(). If that
3877 * is the final reference count, the device will be cleaned up
3878 * via device_release() above. Otherwise, the structure will
3879 * stick around until the final reference to the device is dropped.
3881 void device_unregister(struct device *dev)
3883 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3887 EXPORT_SYMBOL_GPL(device_unregister);
3889 static struct device *prev_device(struct klist_iter *i)
3891 struct klist_node *n = klist_prev(i);
3892 struct device *dev = NULL;
3893 struct device_private *p;
3896 p = to_device_private_parent(n);
3902 static struct device *next_device(struct klist_iter *i)
3904 struct klist_node *n = klist_next(i);
3905 struct device *dev = NULL;
3906 struct device_private *p;
3909 p = to_device_private_parent(n);
3916 * device_get_devnode - path of device node file
3918 * @mode: returned file access mode
3919 * @uid: returned file owner
3920 * @gid: returned file group
3921 * @tmp: possibly allocated string
3923 * Return the relative path of a possible device node.
3924 * Non-default names may need to allocate a memory to compose
3925 * a name. This memory is returned in tmp and needs to be
3926 * freed by the caller.
3928 const char *device_get_devnode(const struct device *dev,
3929 umode_t *mode, kuid_t *uid, kgid_t *gid,
3936 /* the device type may provide a specific name */
3937 if (dev->type && dev->type->devnode)
3938 *tmp = dev->type->devnode(dev, mode, uid, gid);
3942 /* the class may provide a specific name */
3943 if (dev->class && dev->class->devnode)
3944 *tmp = dev->class->devnode(dev, mode);
3948 /* return name without allocation, tmp == NULL */
3949 if (strchr(dev_name(dev), '!') == NULL)
3950 return dev_name(dev);
3952 /* replace '!' in the name with '/' */
3953 s = kstrdup_and_replace(dev_name(dev), '!', '/', GFP_KERNEL);
3960 * device_for_each_child - device child iterator.
3961 * @parent: parent struct device.
3962 * @fn: function to be called for each device.
3963 * @data: data for the callback.
3965 * Iterate over @parent's child devices, and call @fn for each,
3968 * We check the return of @fn each time. If it returns anything
3969 * other than 0, we break out and return that value.
3971 int device_for_each_child(struct device *parent, void *data,
3972 int (*fn)(struct device *dev, void *data))
3974 struct klist_iter i;
3975 struct device *child;
3981 klist_iter_init(&parent->p->klist_children, &i);
3982 while (!error && (child = next_device(&i)))
3983 error = fn(child, data);
3984 klist_iter_exit(&i);
3987 EXPORT_SYMBOL_GPL(device_for_each_child);
3990 * device_for_each_child_reverse - device child iterator in reversed order.
3991 * @parent: parent struct device.
3992 * @fn: function to be called for each device.
3993 * @data: data for the callback.
3995 * Iterate over @parent's child devices, and call @fn for each,
3998 * We check the return of @fn each time. If it returns anything
3999 * other than 0, we break out and return that value.
4001 int device_for_each_child_reverse(struct device *parent, void *data,
4002 int (*fn)(struct device *dev, void *data))
4004 struct klist_iter i;
4005 struct device *child;
4011 klist_iter_init(&parent->p->klist_children, &i);
4012 while ((child = prev_device(&i)) && !error)
4013 error = fn(child, data);
4014 klist_iter_exit(&i);
4017 EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
4020 * device_find_child - device iterator for locating a particular device.
4021 * @parent: parent struct device
4022 * @match: Callback function to check device
4023 * @data: Data to pass to match function
4025 * This is similar to the device_for_each_child() function above, but it
4026 * returns a reference to a device that is 'found' for later use, as
4027 * determined by the @match callback.
4029 * The callback should return 0 if the device doesn't match and non-zero
4030 * if it does. If the callback returns non-zero and a reference to the
4031 * current device can be obtained, this function will return to the caller
4032 * and not iterate over any more devices.
4034 * NOTE: you will need to drop the reference with put_device() after use.
4036 struct device *device_find_child(struct device *parent, void *data,
4037 int (*match)(struct device *dev, void *data))
4039 struct klist_iter i;
4040 struct device *child;
4045 klist_iter_init(&parent->p->klist_children, &i);
4046 while ((child = next_device(&i)))
4047 if (match(child, data) && get_device(child))
4049 klist_iter_exit(&i);
4052 EXPORT_SYMBOL_GPL(device_find_child);
4055 * device_find_child_by_name - device iterator for locating a child device.
4056 * @parent: parent struct device
4057 * @name: name of the child device
4059 * This is similar to the device_find_child() function above, but it
4060 * returns a reference to a device that has the name @name.
4062 * NOTE: you will need to drop the reference with put_device() after use.
4064 struct device *device_find_child_by_name(struct device *parent,
4067 struct klist_iter i;
4068 struct device *child;
4073 klist_iter_init(&parent->p->klist_children, &i);
4074 while ((child = next_device(&i)))
4075 if (sysfs_streq(dev_name(child), name) && get_device(child))
4077 klist_iter_exit(&i);
4080 EXPORT_SYMBOL_GPL(device_find_child_by_name);
4082 static int match_any(struct device *dev, void *unused)
4088 * device_find_any_child - device iterator for locating a child device, if any.
4089 * @parent: parent struct device
4091 * This is similar to the device_find_child() function above, but it
4092 * returns a reference to a child device, if any.
4094 * NOTE: you will need to drop the reference with put_device() after use.
4096 struct device *device_find_any_child(struct device *parent)
4098 return device_find_child(parent, NULL, match_any);
4100 EXPORT_SYMBOL_GPL(device_find_any_child);
4102 int __init devices_init(void)
4104 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
4107 dev_kobj = kobject_create_and_add("dev", NULL);
4110 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
4111 if (!sysfs_dev_block_kobj)
4112 goto block_kobj_err;
4113 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
4114 if (!sysfs_dev_char_kobj)
4116 device_link_wq = alloc_workqueue("device_link_wq", 0, 0);
4117 if (!device_link_wq)
4123 kobject_put(sysfs_dev_char_kobj);
4125 kobject_put(sysfs_dev_block_kobj);
4127 kobject_put(dev_kobj);
4129 kset_unregister(devices_kset);
4133 static int device_check_offline(struct device *dev, void *not_used)
4137 ret = device_for_each_child(dev, NULL, device_check_offline);
4141 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
4145 * device_offline - Prepare the device for hot-removal.
4146 * @dev: Device to be put offline.
4148 * Execute the device bus type's .offline() callback, if present, to prepare
4149 * the device for a subsequent hot-removal. If that succeeds, the device must
4150 * not be used until either it is removed or its bus type's .online() callback
4153 * Call under device_hotplug_lock.
4155 int device_offline(struct device *dev)
4159 if (dev->offline_disabled)
4162 ret = device_for_each_child(dev, NULL, device_check_offline);
4167 if (device_supports_offline(dev)) {
4171 ret = dev->bus->offline(dev);
4173 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
4174 dev->offline = true;
4184 * device_online - Put the device back online after successful device_offline().
4185 * @dev: Device to be put back online.
4187 * If device_offline() has been successfully executed for @dev, but the device
4188 * has not been removed subsequently, execute its bus type's .online() callback
4189 * to indicate that the device can be used again.
4191 * Call under device_hotplug_lock.
4193 int device_online(struct device *dev)
4198 if (device_supports_offline(dev)) {
4200 ret = dev->bus->online(dev);
4202 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
4203 dev->offline = false;
4214 struct root_device {
4216 struct module *owner;
4219 static inline struct root_device *to_root_device(struct device *d)
4221 return container_of(d, struct root_device, dev);
4224 static void root_device_release(struct device *dev)
4226 kfree(to_root_device(dev));
4230 * __root_device_register - allocate and register a root device
4231 * @name: root device name
4232 * @owner: owner module of the root device, usually THIS_MODULE
4234 * This function allocates a root device and registers it
4235 * using device_register(). In order to free the returned
4236 * device, use root_device_unregister().
4238 * Root devices are dummy devices which allow other devices
4239 * to be grouped under /sys/devices. Use this function to
4240 * allocate a root device and then use it as the parent of
4241 * any device which should appear under /sys/devices/{name}
4243 * The /sys/devices/{name} directory will also contain a
4244 * 'module' symlink which points to the @owner directory
4247 * Returns &struct device pointer on success, or ERR_PTR() on error.
4249 * Note: You probably want to use root_device_register().
4251 struct device *__root_device_register(const char *name, struct module *owner)
4253 struct root_device *root;
4256 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
4258 return ERR_PTR(err);
4260 err = dev_set_name(&root->dev, "%s", name);
4263 return ERR_PTR(err);
4266 root->dev.release = root_device_release;
4268 err = device_register(&root->dev);
4270 put_device(&root->dev);
4271 return ERR_PTR(err);
4274 #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */
4276 struct module_kobject *mk = &owner->mkobj;
4278 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
4280 device_unregister(&root->dev);
4281 return ERR_PTR(err);
4283 root->owner = owner;
4289 EXPORT_SYMBOL_GPL(__root_device_register);
4292 * root_device_unregister - unregister and free a root device
4293 * @dev: device going away
4295 * This function unregisters and cleans up a device that was created by
4296 * root_device_register().
4298 void root_device_unregister(struct device *dev)
4300 struct root_device *root = to_root_device(dev);
4303 sysfs_remove_link(&root->dev.kobj, "module");
4305 device_unregister(dev);
4307 EXPORT_SYMBOL_GPL(root_device_unregister);
4310 static void device_create_release(struct device *dev)
4312 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
4316 static __printf(6, 0) struct device *
4317 device_create_groups_vargs(const struct class *class, struct device *parent,
4318 dev_t devt, void *drvdata,
4319 const struct attribute_group **groups,
4320 const char *fmt, va_list args)
4322 struct device *dev = NULL;
4323 int retval = -ENODEV;
4325 if (IS_ERR_OR_NULL(class))
4328 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
4334 device_initialize(dev);
4337 dev->parent = parent;
4338 dev->groups = groups;
4339 dev->release = device_create_release;
4340 dev_set_drvdata(dev, drvdata);
4342 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
4346 retval = device_add(dev);
4354 return ERR_PTR(retval);
4358 * device_create - creates a device and registers it with sysfs
4359 * @class: pointer to the struct class that this device should be registered to
4360 * @parent: pointer to the parent struct device of this new device, if any
4361 * @devt: the dev_t for the char device to be added
4362 * @drvdata: the data to be added to the device for callbacks
4363 * @fmt: string for the device's name
4365 * This function can be used by char device classes. A struct device
4366 * will be created in sysfs, registered to the specified class.
4368 * A "dev" file will be created, showing the dev_t for the device, if
4369 * the dev_t is not 0,0.
4370 * If a pointer to a parent struct device is passed in, the newly created
4371 * struct device will be a child of that device in sysfs.
4372 * The pointer to the struct device will be returned from the call.
4373 * Any further sysfs files that might be required can be created using this
4376 * Returns &struct device pointer on success, or ERR_PTR() on error.
4378 struct device *device_create(const struct class *class, struct device *parent,
4379 dev_t devt, void *drvdata, const char *fmt, ...)
4384 va_start(vargs, fmt);
4385 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL,
4390 EXPORT_SYMBOL_GPL(device_create);
4393 * device_create_with_groups - creates a device and registers it with sysfs
4394 * @class: pointer to the struct class that this device should be registered to
4395 * @parent: pointer to the parent struct device of this new device, if any
4396 * @devt: the dev_t for the char device to be added
4397 * @drvdata: the data to be added to the device for callbacks
4398 * @groups: NULL-terminated list of attribute groups to be created
4399 * @fmt: string for the device's name
4401 * This function can be used by char device classes. A struct device
4402 * will be created in sysfs, registered to the specified class.
4403 * Additional attributes specified in the groups parameter will also
4404 * be created automatically.
4406 * A "dev" file will be created, showing the dev_t for the device, if
4407 * the dev_t is not 0,0.
4408 * If a pointer to a parent struct device is passed in, the newly created
4409 * struct device will be a child of that device in sysfs.
4410 * The pointer to the struct device will be returned from the call.
4411 * Any further sysfs files that might be required can be created using this
4414 * Returns &struct device pointer on success, or ERR_PTR() on error.
4416 struct device *device_create_with_groups(const struct class *class,
4417 struct device *parent, dev_t devt,
4419 const struct attribute_group **groups,
4420 const char *fmt, ...)
4425 va_start(vargs, fmt);
4426 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups,
4431 EXPORT_SYMBOL_GPL(device_create_with_groups);
4434 * device_destroy - removes a device that was created with device_create()
4435 * @class: pointer to the struct class that this device was registered with
4436 * @devt: the dev_t of the device that was previously registered
4438 * This call unregisters and cleans up a device that was created with a
4439 * call to device_create().
4441 void device_destroy(const struct class *class, dev_t devt)
4445 dev = class_find_device_by_devt(class, devt);
4448 device_unregister(dev);
4451 EXPORT_SYMBOL_GPL(device_destroy);
4454 * device_rename - renames a device
4455 * @dev: the pointer to the struct device to be renamed
4456 * @new_name: the new name of the device
4458 * It is the responsibility of the caller to provide mutual
4459 * exclusion between two different calls of device_rename
4460 * on the same device to ensure that new_name is valid and
4461 * won't conflict with other devices.
4463 * Note: given that some subsystems (networking and infiniband) use this
4464 * function, with no immediate plans for this to change, we cannot assume or
4465 * require that this function not be called at all.
4467 * However, if you're writing new code, do not call this function. The following
4468 * text from Kay Sievers offers some insight:
4470 * Renaming devices is racy at many levels, symlinks and other stuff are not
4471 * replaced atomically, and you get a "move" uevent, but it's not easy to
4472 * connect the event to the old and new device. Device nodes are not renamed at
4473 * all, there isn't even support for that in the kernel now.
4475 * In the meantime, during renaming, your target name might be taken by another
4476 * driver, creating conflicts. Or the old name is taken directly after you
4477 * renamed it -- then you get events for the same DEVPATH, before you even see
4478 * the "move" event. It's just a mess, and nothing new should ever rely on
4479 * kernel device renaming. Besides that, it's not even implemented now for
4480 * other things than (driver-core wise very simple) network devices.
4482 * Make up a "real" name in the driver before you register anything, or add
4483 * some other attributes for userspace to find the device, or use udev to add
4484 * symlinks -- but never rename kernel devices later, it's a complete mess. We
4485 * don't even want to get into that and try to implement the missing pieces in
4486 * the core. We really have other pieces to fix in the driver core mess. :)
4488 int device_rename(struct device *dev, const char *new_name)
4490 struct kobject *kobj = &dev->kobj;
4491 char *old_device_name = NULL;
4494 dev = get_device(dev);
4498 dev_dbg(dev, "renaming to %s\n", new_name);
4500 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
4501 if (!old_device_name) {
4507 struct subsys_private *sp = class_to_subsys(dev->class);
4514 error = sysfs_rename_link_ns(&sp->subsys.kobj, kobj, old_device_name,
4515 new_name, kobject_namespace(kobj));
4521 error = kobject_rename(kobj, new_name);
4528 kfree(old_device_name);
4532 EXPORT_SYMBOL_GPL(device_rename);
4534 static int device_move_class_links(struct device *dev,
4535 struct device *old_parent,
4536 struct device *new_parent)
4541 sysfs_remove_link(&dev->kobj, "device");
4543 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
4549 * device_move - moves a device to a new parent
4550 * @dev: the pointer to the struct device to be moved
4551 * @new_parent: the new parent of the device (can be NULL)
4552 * @dpm_order: how to reorder the dpm_list
4554 int device_move(struct device *dev, struct device *new_parent,
4555 enum dpm_order dpm_order)
4558 struct device *old_parent;
4559 struct kobject *new_parent_kobj;
4561 dev = get_device(dev);
4566 new_parent = get_device(new_parent);
4567 new_parent_kobj = get_device_parent(dev, new_parent);
4568 if (IS_ERR(new_parent_kobj)) {
4569 error = PTR_ERR(new_parent_kobj);
4570 put_device(new_parent);
4574 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
4575 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
4576 error = kobject_move(&dev->kobj, new_parent_kobj);
4578 cleanup_glue_dir(dev, new_parent_kobj);
4579 put_device(new_parent);
4582 old_parent = dev->parent;
4583 dev->parent = new_parent;
4585 klist_remove(&dev->p->knode_parent);
4587 klist_add_tail(&dev->p->knode_parent,
4588 &new_parent->p->klist_children);
4589 set_dev_node(dev, dev_to_node(new_parent));
4593 error = device_move_class_links(dev, old_parent, new_parent);
4595 /* We ignore errors on cleanup since we're hosed anyway... */
4596 device_move_class_links(dev, new_parent, old_parent);
4597 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
4599 klist_remove(&dev->p->knode_parent);
4600 dev->parent = old_parent;
4602 klist_add_tail(&dev->p->knode_parent,
4603 &old_parent->p->klist_children);
4604 set_dev_node(dev, dev_to_node(old_parent));
4607 cleanup_glue_dir(dev, new_parent_kobj);
4608 put_device(new_parent);
4612 switch (dpm_order) {
4613 case DPM_ORDER_NONE:
4615 case DPM_ORDER_DEV_AFTER_PARENT:
4616 device_pm_move_after(dev, new_parent);
4617 devices_kset_move_after(dev, new_parent);
4619 case DPM_ORDER_PARENT_BEFORE_DEV:
4620 device_pm_move_before(new_parent, dev);
4621 devices_kset_move_before(new_parent, dev);
4623 case DPM_ORDER_DEV_LAST:
4624 device_pm_move_last(dev);
4625 devices_kset_move_last(dev);
4629 put_device(old_parent);
4635 EXPORT_SYMBOL_GPL(device_move);
4637 static int device_attrs_change_owner(struct device *dev, kuid_t kuid,
4640 struct kobject *kobj = &dev->kobj;
4641 const struct class *class = dev->class;
4642 const struct device_type *type = dev->type;
4647 * Change the device groups of the device class for @dev to
4650 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid,
4658 * Change the device groups of the device type for @dev to
4661 error = sysfs_groups_change_owner(kobj, type->groups, kuid,
4667 /* Change the device groups of @dev to @kuid/@kgid. */
4668 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid);
4672 if (device_supports_offline(dev) && !dev->offline_disabled) {
4673 /* Change online device attributes of @dev to @kuid/@kgid. */
4674 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name,
4684 * device_change_owner - change the owner of an existing device.
4686 * @kuid: new owner's kuid
4687 * @kgid: new owner's kgid
4689 * This changes the owner of @dev and its corresponding sysfs entries to
4690 * @kuid/@kgid. This function closely mirrors how @dev was added via driver
4693 * Returns 0 on success or error code on failure.
4695 int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
4698 struct kobject *kobj = &dev->kobj;
4699 struct subsys_private *sp;
4701 dev = get_device(dev);
4706 * Change the kobject and the default attributes and groups of the
4707 * ktype associated with it to @kuid/@kgid.
4709 error = sysfs_change_owner(kobj, kuid, kgid);
4714 * Change the uevent file for @dev to the new owner. The uevent file
4715 * was created in a separate step when @dev got added and we mirror
4718 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid,
4724 * Change the device groups, the device groups associated with the
4725 * device class, and the groups associated with the device type of @dev
4728 error = device_attrs_change_owner(dev, kuid, kgid);
4732 error = dpm_sysfs_change_owner(dev, kuid, kgid);
4737 * Change the owner of the symlink located in the class directory of
4738 * the device class associated with @dev which points to the actual
4739 * directory entry for @dev to @kuid/@kgid. This ensures that the
4740 * symlink shows the same permissions as its target.
4742 sp = class_to_subsys(dev->class);
4747 error = sysfs_link_change_owner(&sp->subsys.kobj, &dev->kobj, dev_name(dev), kuid, kgid);
4754 EXPORT_SYMBOL_GPL(device_change_owner);
4757 * device_shutdown - call ->shutdown() on each device to shutdown.
4759 void device_shutdown(void)
4761 struct device *dev, *parent;
4763 wait_for_device_probe();
4764 device_block_probing();
4768 spin_lock(&devices_kset->list_lock);
4770 * Walk the devices list backward, shutting down each in turn.
4771 * Beware that device unplug events may also start pulling
4772 * devices offline, even as the system is shutting down.
4774 while (!list_empty(&devices_kset->list)) {
4775 dev = list_entry(devices_kset->list.prev, struct device,
4779 * hold reference count of device's parent to
4780 * prevent it from being freed because parent's
4781 * lock is to be held
4783 parent = get_device(dev->parent);
4786 * Make sure the device is off the kset list, in the
4787 * event that dev->*->shutdown() doesn't remove it.
4789 list_del_init(&dev->kobj.entry);
4790 spin_unlock(&devices_kset->list_lock);
4792 /* hold lock to avoid race with probe/release */
4794 device_lock(parent);
4797 /* Don't allow any more runtime suspends */
4798 pm_runtime_get_noresume(dev);
4799 pm_runtime_barrier(dev);
4801 if (dev->class && dev->class->shutdown_pre) {
4803 dev_info(dev, "shutdown_pre\n");
4804 dev->class->shutdown_pre(dev);
4806 if (dev->bus && dev->bus->shutdown) {
4808 dev_info(dev, "shutdown\n");
4809 dev->bus->shutdown(dev);
4810 } else if (dev->driver && dev->driver->shutdown) {
4812 dev_info(dev, "shutdown\n");
4813 dev->driver->shutdown(dev);
4818 device_unlock(parent);
4823 spin_lock(&devices_kset->list_lock);
4825 spin_unlock(&devices_kset->list_lock);
4829 * Device logging functions
4832 #ifdef CONFIG_PRINTK
4834 set_dev_info(const struct device *dev, struct dev_printk_info *dev_info)
4838 memset(dev_info, 0, sizeof(*dev_info));
4841 subsys = dev->class->name;
4843 subsys = dev->bus->name;
4847 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem));
4850 * Add device identifier DEVICE=:
4854 * +sound:card0 subsystem:devname
4856 if (MAJOR(dev->devt)) {
4859 if (strcmp(subsys, "block") == 0)
4864 snprintf(dev_info->device, sizeof(dev_info->device),
4865 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt));
4866 } else if (strcmp(subsys, "net") == 0) {
4867 struct net_device *net = to_net_dev(dev);
4869 snprintf(dev_info->device, sizeof(dev_info->device),
4870 "n%u", net->ifindex);
4872 snprintf(dev_info->device, sizeof(dev_info->device),
4873 "+%s:%s", subsys, dev_name(dev));
4877 int dev_vprintk_emit(int level, const struct device *dev,
4878 const char *fmt, va_list args)
4880 struct dev_printk_info dev_info;
4882 set_dev_info(dev, &dev_info);
4884 return vprintk_emit(0, level, &dev_info, fmt, args);
4886 EXPORT_SYMBOL(dev_vprintk_emit);
4888 int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
4893 va_start(args, fmt);
4895 r = dev_vprintk_emit(level, dev, fmt, args);
4901 EXPORT_SYMBOL(dev_printk_emit);
4903 static void __dev_printk(const char *level, const struct device *dev,
4904 struct va_format *vaf)
4907 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV",
4908 dev_driver_string(dev), dev_name(dev), vaf);
4910 printk("%s(NULL device *): %pV", level, vaf);
4913 void _dev_printk(const char *level, const struct device *dev,
4914 const char *fmt, ...)
4916 struct va_format vaf;
4919 va_start(args, fmt);
4924 __dev_printk(level, dev, &vaf);
4928 EXPORT_SYMBOL(_dev_printk);
4930 #define define_dev_printk_level(func, kern_level) \
4931 void func(const struct device *dev, const char *fmt, ...) \
4933 struct va_format vaf; \
4936 va_start(args, fmt); \
4941 __dev_printk(kern_level, dev, &vaf); \
4945 EXPORT_SYMBOL(func);
4947 define_dev_printk_level(_dev_emerg, KERN_EMERG);
4948 define_dev_printk_level(_dev_alert, KERN_ALERT);
4949 define_dev_printk_level(_dev_crit, KERN_CRIT);
4950 define_dev_printk_level(_dev_err, KERN_ERR);
4951 define_dev_printk_level(_dev_warn, KERN_WARNING);
4952 define_dev_printk_level(_dev_notice, KERN_NOTICE);
4953 define_dev_printk_level(_dev_info, KERN_INFO);
4958 * dev_err_probe - probe error check and log helper
4959 * @dev: the pointer to the struct device
4960 * @err: error value to test
4961 * @fmt: printf-style format string
4962 * @...: arguments as specified in the format string
4964 * This helper implements common pattern present in probe functions for error
4965 * checking: print debug or error message depending if the error value is
4966 * -EPROBE_DEFER and propagate error upwards.
4967 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
4968 * checked later by reading devices_deferred debugfs attribute.
4969 * It replaces code sequence::
4971 * if (err != -EPROBE_DEFER)
4972 * dev_err(dev, ...);
4974 * dev_dbg(dev, ...);
4979 * return dev_err_probe(dev, err, ...);
4981 * Using this helper in your probe function is totally fine even if @err is
4982 * known to never be -EPROBE_DEFER.
4983 * The benefit compared to a normal dev_err() is the standardized format
4984 * of the error code, it being emitted symbolically (i.e. you get "EAGAIN"
4985 * instead of "-35") and the fact that the error code is returned which allows
4986 * more compact error paths.
4990 int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
4992 struct va_format vaf;
4995 va_start(args, fmt);
4999 if (err != -EPROBE_DEFER) {
5000 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
5002 device_set_deferred_probe_reason(dev, &vaf);
5003 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
5010 EXPORT_SYMBOL_GPL(dev_err_probe);
5012 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
5014 return fwnode && !IS_ERR(fwnode->secondary);
5018 * set_primary_fwnode - Change the primary firmware node of a given device.
5019 * @dev: Device to handle.
5020 * @fwnode: New primary firmware node of the device.
5022 * Set the device's firmware node pointer to @fwnode, but if a secondary
5023 * firmware node of the device is present, preserve it.
5025 * Valid fwnode cases are:
5026 * - primary --> secondary --> -ENODEV
5027 * - primary --> NULL
5028 * - secondary --> -ENODEV
5031 void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5033 struct device *parent = dev->parent;
5034 struct fwnode_handle *fn = dev->fwnode;
5037 if (fwnode_is_primary(fn))
5041 WARN_ON(fwnode->secondary);
5042 fwnode->secondary = fn;
5044 dev->fwnode = fwnode;
5046 if (fwnode_is_primary(fn)) {
5047 dev->fwnode = fn->secondary;
5049 /* Skip nullifying fn->secondary if the primary is shared */
5050 if (parent && fn == parent->fwnode)
5053 /* Set fn->secondary = NULL, so fn remains the primary fwnode */
5054 fn->secondary = NULL;
5060 EXPORT_SYMBOL_GPL(set_primary_fwnode);
5063 * set_secondary_fwnode - Change the secondary firmware node of a given device.
5064 * @dev: Device to handle.
5065 * @fwnode: New secondary firmware node of the device.
5067 * If a primary firmware node of the device is present, set its secondary
5068 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
5071 void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
5074 fwnode->secondary = ERR_PTR(-ENODEV);
5076 if (fwnode_is_primary(dev->fwnode))
5077 dev->fwnode->secondary = fwnode;
5079 dev->fwnode = fwnode;
5081 EXPORT_SYMBOL_GPL(set_secondary_fwnode);
5084 * device_set_of_node_from_dev - reuse device-tree node of another device
5085 * @dev: device whose device-tree node is being set
5086 * @dev2: device whose device-tree node is being reused
5088 * Takes another reference to the new device-tree node after first dropping
5089 * any reference held to the old node.
5091 void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
5093 of_node_put(dev->of_node);
5094 dev->of_node = of_node_get(dev2->of_node);
5095 dev->of_node_reused = true;
5097 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
5099 void device_set_node(struct device *dev, struct fwnode_handle *fwnode)
5101 dev->fwnode = fwnode;
5102 dev->of_node = to_of_node(fwnode);
5104 EXPORT_SYMBOL_GPL(device_set_node);
5106 int device_match_name(struct device *dev, const void *name)
5108 return sysfs_streq(dev_name(dev), name);
5110 EXPORT_SYMBOL_GPL(device_match_name);
5112 int device_match_of_node(struct device *dev, const void *np)
5114 return dev->of_node == np;
5116 EXPORT_SYMBOL_GPL(device_match_of_node);
5118 int device_match_fwnode(struct device *dev, const void *fwnode)
5120 return dev_fwnode(dev) == fwnode;
5122 EXPORT_SYMBOL_GPL(device_match_fwnode);
5124 int device_match_devt(struct device *dev, const void *pdevt)
5126 return dev->devt == *(dev_t *)pdevt;
5128 EXPORT_SYMBOL_GPL(device_match_devt);
5130 int device_match_acpi_dev(struct device *dev, const void *adev)
5132 return ACPI_COMPANION(dev) == adev;
5134 EXPORT_SYMBOL(device_match_acpi_dev);
5136 int device_match_acpi_handle(struct device *dev, const void *handle)
5138 return ACPI_HANDLE(dev) == handle;
5140 EXPORT_SYMBOL(device_match_acpi_handle);
5142 int device_match_any(struct device *dev, const void *unused)
5146 EXPORT_SYMBOL_GPL(device_match_any);