1 // SPDX-License-Identifier: GPL-2.0
3 * drivers/base/power/runtime.c - Helper functions for device runtime PM
5 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
6 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
8 #include <linux/sched/mm.h>
9 #include <linux/ktime.h>
10 #include <linux/hrtimer.h>
11 #include <linux/export.h>
12 #include <linux/pm_runtime.h>
13 #include <linux/pm_wakeirq.h>
14 #include <trace/events/rpm.h>
19 typedef int (*pm_callback_t)(struct device *);
21 static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
24 const struct dev_pm_ops *ops;
27 ops = &dev->pm_domain->ops;
28 else if (dev->type && dev->type->pm)
30 else if (dev->class && dev->class->pm)
32 else if (dev->bus && dev->bus->pm)
38 cb = *(pm_callback_t *)((void *)ops + cb_offset);
42 if (!cb && dev->driver && dev->driver->pm)
43 cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
48 #define RPM_GET_CALLBACK(dev, callback) \
49 __rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
51 static int rpm_resume(struct device *dev, int rpmflags);
52 static int rpm_suspend(struct device *dev, int rpmflags);
55 * update_pm_runtime_accounting - Update the time accounting of power states
56 * @dev: Device to update the accounting for
58 * In order to be able to have time accounting of the various power states
59 * (as used by programs such as PowerTOP to show the effectiveness of runtime
60 * PM), we need to track the time spent in each state.
61 * update_pm_runtime_accounting must be called each time before the
62 * runtime_status field is updated, to account the time in the old state
65 static void update_pm_runtime_accounting(struct device *dev)
69 if (dev->power.disable_depth > 0)
72 last = dev->power.accounting_timestamp;
74 now = ktime_get_mono_fast_ns();
75 dev->power.accounting_timestamp = now;
78 * Because ktime_get_mono_fast_ns() is not monotonic during
79 * timekeeping updates, ensure that 'now' is after the last saved
87 if (dev->power.runtime_status == RPM_SUSPENDED)
88 dev->power.suspended_time += delta;
90 dev->power.active_time += delta;
93 static void __update_runtime_status(struct device *dev, enum rpm_status status)
95 update_pm_runtime_accounting(dev);
96 dev->power.runtime_status = status;
99 static u64 rpm_get_accounted_time(struct device *dev, bool suspended)
104 spin_lock_irqsave(&dev->power.lock, flags);
106 update_pm_runtime_accounting(dev);
107 time = suspended ? dev->power.suspended_time : dev->power.active_time;
109 spin_unlock_irqrestore(&dev->power.lock, flags);
114 u64 pm_runtime_active_time(struct device *dev)
116 return rpm_get_accounted_time(dev, false);
119 u64 pm_runtime_suspended_time(struct device *dev)
121 return rpm_get_accounted_time(dev, true);
123 EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
126 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
127 * @dev: Device to handle.
129 static void pm_runtime_deactivate_timer(struct device *dev)
131 if (dev->power.timer_expires > 0) {
132 hrtimer_try_to_cancel(&dev->power.suspend_timer);
133 dev->power.timer_expires = 0;
138 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
139 * @dev: Device to handle.
141 static void pm_runtime_cancel_pending(struct device *dev)
143 pm_runtime_deactivate_timer(dev);
145 * In case there's a request pending, make sure its work function will
146 * return without doing anything.
148 dev->power.request = RPM_REQ_NONE;
152 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
153 * @dev: Device to handle.
155 * Compute the autosuspend-delay expiration time based on the device's
156 * power.last_busy time. If the delay has already expired or is disabled
157 * (negative) or the power.use_autosuspend flag isn't set, return 0.
158 * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero).
160 * This function may be called either with or without dev->power.lock held.
161 * Either way it can be racy, since power.last_busy may be updated at any time.
163 u64 pm_runtime_autosuspend_expiration(struct device *dev)
165 int autosuspend_delay;
168 if (!dev->power.use_autosuspend)
171 autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
172 if (autosuspend_delay < 0)
175 expires = READ_ONCE(dev->power.last_busy);
176 expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
177 if (expires > ktime_get_mono_fast_ns())
178 return expires; /* Expires in the future */
182 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
184 static int dev_memalloc_noio(struct device *dev, void *data)
186 return dev->power.memalloc_noio;
190 * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
191 * @dev: Device to handle.
192 * @enable: True for setting the flag and False for clearing the flag.
194 * Set the flag for all devices in the path from the device to the
195 * root device in the device tree if @enable is true, otherwise clear
196 * the flag for devices in the path whose siblings don't set the flag.
198 * The function should only be called by block device, or network
199 * device driver for solving the deadlock problem during runtime
202 * If memory allocation with GFP_KERNEL is called inside runtime
203 * resume/suspend callback of any one of its ancestors(or the
204 * block device itself), the deadlock may be triggered inside the
205 * memory allocation since it might not complete until the block
206 * device becomes active and the involed page I/O finishes. The
207 * situation is pointed out first by Alan Stern. Network device
208 * are involved in iSCSI kind of situation.
210 * The lock of dev_hotplug_mutex is held in the function for handling
211 * hotplug race because pm_runtime_set_memalloc_noio() may be called
214 * The function should be called between device_add() and device_del()
215 * on the affected device(block/network device).
217 void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
219 static DEFINE_MUTEX(dev_hotplug_mutex);
221 mutex_lock(&dev_hotplug_mutex);
225 /* hold power lock since bitfield is not SMP-safe. */
226 spin_lock_irq(&dev->power.lock);
227 enabled = dev->power.memalloc_noio;
228 dev->power.memalloc_noio = enable;
229 spin_unlock_irq(&dev->power.lock);
232 * not need to enable ancestors any more if the device
235 if (enabled && enable)
241 * clear flag of the parent device only if all the
242 * children don't set the flag because ancestor's
243 * flag was set by any one of the descendants.
245 if (!dev || (!enable &&
246 device_for_each_child(dev, NULL,
250 mutex_unlock(&dev_hotplug_mutex);
252 EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
255 * rpm_check_suspend_allowed - Test whether a device may be suspended.
256 * @dev: Device to test.
258 static int rpm_check_suspend_allowed(struct device *dev)
262 if (dev->power.runtime_error)
264 else if (dev->power.disable_depth > 0)
266 else if (atomic_read(&dev->power.usage_count) > 0)
268 else if (!dev->power.ignore_children &&
269 atomic_read(&dev->power.child_count))
272 /* Pending resume requests take precedence over suspends. */
273 else if ((dev->power.deferred_resume
274 && dev->power.runtime_status == RPM_SUSPENDING)
275 || (dev->power.request_pending
276 && dev->power.request == RPM_REQ_RESUME))
278 else if (__dev_pm_qos_resume_latency(dev) == 0)
280 else if (dev->power.runtime_status == RPM_SUSPENDED)
286 static int rpm_get_suppliers(struct device *dev)
288 struct device_link *link;
290 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
291 device_links_read_lock_held()) {
294 if (!(link->flags & DL_FLAG_PM_RUNTIME))
297 retval = pm_runtime_get_sync(link->supplier);
298 /* Ignore suppliers with disabled runtime PM. */
299 if (retval < 0 && retval != -EACCES) {
300 pm_runtime_put_noidle(link->supplier);
303 refcount_inc(&link->rpm_active);
308 static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
310 struct device_link *link;
312 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
313 device_links_read_lock_held()) {
315 while (refcount_dec_not_one(&link->rpm_active))
316 pm_runtime_put_noidle(link->supplier);
319 pm_request_idle(link->supplier);
323 static void rpm_put_suppliers(struct device *dev)
325 __rpm_put_suppliers(dev, true);
328 static void rpm_suspend_suppliers(struct device *dev)
330 struct device_link *link;
331 int idx = device_links_read_lock();
333 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
334 device_links_read_lock_held())
335 pm_request_idle(link->supplier);
337 device_links_read_unlock(idx);
341 * __rpm_callback - Run a given runtime PM callback for a given device.
342 * @cb: Runtime PM callback to run.
343 * @dev: Device to run the callback for.
345 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
346 __releases(&dev->power.lock) __acquires(&dev->power.lock)
349 bool use_links = dev->power.links_count > 0;
351 if (dev->power.irq_safe) {
352 spin_unlock(&dev->power.lock);
354 spin_unlock_irq(&dev->power.lock);
357 * Resume suppliers if necessary.
359 * The device's runtime PM status cannot change until this
360 * routine returns, so it is safe to read the status outside of
363 if (use_links && dev->power.runtime_status == RPM_RESUMING) {
364 idx = device_links_read_lock();
366 retval = rpm_get_suppliers(dev);
368 rpm_put_suppliers(dev);
372 device_links_read_unlock(idx);
378 if (dev->power.irq_safe) {
379 spin_lock(&dev->power.lock);
382 * If the device is suspending and the callback has returned
383 * success, drop the usage counters of the suppliers that have
384 * been reference counted on its resume.
386 * Do that if resume fails too.
389 && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
390 || (dev->power.runtime_status == RPM_RESUMING && retval))) {
391 idx = device_links_read_lock();
393 __rpm_put_suppliers(dev, false);
396 device_links_read_unlock(idx);
399 spin_lock_irq(&dev->power.lock);
406 * rpm_idle - Notify device bus type if the device can be suspended.
407 * @dev: Device to notify the bus type about.
408 * @rpmflags: Flag bits.
410 * Check if the device's runtime PM status allows it to be suspended. If
411 * another idle notification has been started earlier, return immediately. If
412 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
413 * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
414 * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
416 * This function must be called under dev->power.lock with interrupts disabled.
418 static int rpm_idle(struct device *dev, int rpmflags)
420 int (*callback)(struct device *);
423 trace_rpm_idle_rcuidle(dev, rpmflags);
424 retval = rpm_check_suspend_allowed(dev);
426 ; /* Conditions are wrong. */
428 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
429 else if (dev->power.runtime_status != RPM_ACTIVE)
433 * Any pending request other than an idle notification takes
434 * precedence over us, except that the timer may be running.
436 else if (dev->power.request_pending &&
437 dev->power.request > RPM_REQ_IDLE)
440 /* Act as though RPM_NOWAIT is always set. */
441 else if (dev->power.idle_notification)
442 retval = -EINPROGRESS;
446 /* Pending requests need to be canceled. */
447 dev->power.request = RPM_REQ_NONE;
449 if (dev->power.no_callbacks)
452 /* Carry out an asynchronous or a synchronous idle notification. */
453 if (rpmflags & RPM_ASYNC) {
454 dev->power.request = RPM_REQ_IDLE;
455 if (!dev->power.request_pending) {
456 dev->power.request_pending = true;
457 queue_work(pm_wq, &dev->power.work);
459 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
463 dev->power.idle_notification = true;
465 callback = RPM_GET_CALLBACK(dev, runtime_idle);
468 retval = __rpm_callback(callback, dev);
470 dev->power.idle_notification = false;
471 wake_up_all(&dev->power.wait_queue);
474 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
475 return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
479 * rpm_callback - Run a given runtime PM callback for a given device.
480 * @cb: Runtime PM callback to run.
481 * @dev: Device to run the callback for.
483 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
490 if (dev->power.memalloc_noio) {
491 unsigned int noio_flag;
494 * Deadlock might be caused if memory allocation with
495 * GFP_KERNEL happens inside runtime_suspend and
496 * runtime_resume callbacks of one block device's
497 * ancestor or the block device itself. Network
498 * device might be thought as part of iSCSI block
499 * device, so network device and its ancestor should
500 * be marked as memalloc_noio too.
502 noio_flag = memalloc_noio_save();
503 retval = __rpm_callback(cb, dev);
504 memalloc_noio_restore(noio_flag);
506 retval = __rpm_callback(cb, dev);
509 dev->power.runtime_error = retval;
510 return retval != -EACCES ? retval : -EIO;
514 * rpm_suspend - Carry out runtime suspend of given device.
515 * @dev: Device to suspend.
516 * @rpmflags: Flag bits.
518 * Check if the device's runtime PM status allows it to be suspended.
519 * Cancel a pending idle notification, autosuspend or suspend. If
520 * another suspend has been started earlier, either return immediately
521 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
522 * flags. If the RPM_ASYNC flag is set then queue a suspend request;
523 * otherwise run the ->runtime_suspend() callback directly. When
524 * ->runtime_suspend succeeded, if a deferred resume was requested while
525 * the callback was running then carry it out, otherwise send an idle
526 * notification for its parent (if the suspend succeeded and both
527 * ignore_children of parent->power and irq_safe of dev->power are not set).
528 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
529 * flag is set and the next autosuspend-delay expiration time is in the
530 * future, schedule another autosuspend attempt.
532 * This function must be called under dev->power.lock with interrupts disabled.
534 static int rpm_suspend(struct device *dev, int rpmflags)
535 __releases(&dev->power.lock) __acquires(&dev->power.lock)
537 int (*callback)(struct device *);
538 struct device *parent = NULL;
541 trace_rpm_suspend_rcuidle(dev, rpmflags);
544 retval = rpm_check_suspend_allowed(dev);
546 goto out; /* Conditions are wrong. */
548 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
549 if (dev->power.runtime_status == RPM_RESUMING && !(rpmflags & RPM_ASYNC))
554 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
555 if ((rpmflags & RPM_AUTO)
556 && dev->power.runtime_status != RPM_SUSPENDING) {
557 u64 expires = pm_runtime_autosuspend_expiration(dev);
560 /* Pending requests need to be canceled. */
561 dev->power.request = RPM_REQ_NONE;
564 * Optimization: If the timer is already running and is
565 * set to expire at or before the autosuspend delay,
566 * avoid the overhead of resetting it. Just let it
567 * expire; pm_suspend_timer_fn() will take care of the
570 if (!(dev->power.timer_expires &&
571 dev->power.timer_expires <= expires)) {
573 * We add a slack of 25% to gather wakeups
574 * without sacrificing the granularity.
576 u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) *
577 (NSEC_PER_MSEC >> 2);
579 dev->power.timer_expires = expires;
580 hrtimer_start_range_ns(&dev->power.suspend_timer,
581 ns_to_ktime(expires),
585 dev->power.timer_autosuspends = 1;
590 /* Other scheduled or pending requests need to be canceled. */
591 pm_runtime_cancel_pending(dev);
593 if (dev->power.runtime_status == RPM_SUSPENDING) {
596 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
597 retval = -EINPROGRESS;
601 if (dev->power.irq_safe) {
602 spin_unlock(&dev->power.lock);
606 spin_lock(&dev->power.lock);
610 /* Wait for the other suspend running in parallel with us. */
612 prepare_to_wait(&dev->power.wait_queue, &wait,
613 TASK_UNINTERRUPTIBLE);
614 if (dev->power.runtime_status != RPM_SUSPENDING)
617 spin_unlock_irq(&dev->power.lock);
621 spin_lock_irq(&dev->power.lock);
623 finish_wait(&dev->power.wait_queue, &wait);
627 if (dev->power.no_callbacks)
628 goto no_callback; /* Assume success. */
630 /* Carry out an asynchronous or a synchronous suspend. */
631 if (rpmflags & RPM_ASYNC) {
632 dev->power.request = (rpmflags & RPM_AUTO) ?
633 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
634 if (!dev->power.request_pending) {
635 dev->power.request_pending = true;
636 queue_work(pm_wq, &dev->power.work);
641 __update_runtime_status(dev, RPM_SUSPENDING);
643 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
645 dev_pm_enable_wake_irq_check(dev, true);
646 retval = rpm_callback(callback, dev);
651 __update_runtime_status(dev, RPM_SUSPENDED);
652 pm_runtime_deactivate_timer(dev);
655 parent = dev->parent;
656 atomic_add_unless(&parent->power.child_count, -1, 0);
658 wake_up_all(&dev->power.wait_queue);
660 if (dev->power.deferred_resume) {
661 dev->power.deferred_resume = false;
667 if (dev->power.irq_safe)
670 /* Maybe the parent is now able to suspend. */
671 if (parent && !parent->power.ignore_children) {
672 spin_unlock(&dev->power.lock);
674 spin_lock(&parent->power.lock);
675 rpm_idle(parent, RPM_ASYNC);
676 spin_unlock(&parent->power.lock);
678 spin_lock(&dev->power.lock);
680 /* Maybe the suppliers are now able to suspend. */
681 if (dev->power.links_count > 0) {
682 spin_unlock_irq(&dev->power.lock);
684 rpm_suspend_suppliers(dev);
686 spin_lock_irq(&dev->power.lock);
690 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
695 dev_pm_disable_wake_irq_check(dev);
696 __update_runtime_status(dev, RPM_ACTIVE);
697 dev->power.deferred_resume = false;
698 wake_up_all(&dev->power.wait_queue);
700 if (retval == -EAGAIN || retval == -EBUSY) {
701 dev->power.runtime_error = 0;
704 * If the callback routine failed an autosuspend, and
705 * if the last_busy time has been updated so that there
706 * is a new autosuspend expiration time, automatically
707 * reschedule another autosuspend.
709 if ((rpmflags & RPM_AUTO) &&
710 pm_runtime_autosuspend_expiration(dev) != 0)
713 pm_runtime_cancel_pending(dev);
719 * rpm_resume - Carry out runtime resume of given device.
720 * @dev: Device to resume.
721 * @rpmflags: Flag bits.
723 * Check if the device's runtime PM status allows it to be resumed. Cancel
724 * any scheduled or pending requests. If another resume has been started
725 * earlier, either return immediately or wait for it to finish, depending on the
726 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
727 * parallel with this function, either tell the other process to resume after
728 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
729 * flag is set then queue a resume request; otherwise run the
730 * ->runtime_resume() callback directly. Queue an idle notification for the
731 * device if the resume succeeded.
733 * This function must be called under dev->power.lock with interrupts disabled.
735 static int rpm_resume(struct device *dev, int rpmflags)
736 __releases(&dev->power.lock) __acquires(&dev->power.lock)
738 int (*callback)(struct device *);
739 struct device *parent = NULL;
742 trace_rpm_resume_rcuidle(dev, rpmflags);
745 if (dev->power.runtime_error)
747 else if (dev->power.disable_depth == 1 && dev->power.is_suspended
748 && dev->power.runtime_status == RPM_ACTIVE)
750 else if (dev->power.disable_depth > 0)
756 * Other scheduled or pending requests need to be canceled. Small
757 * optimization: If an autosuspend timer is running, leave it running
758 * rather than cancelling it now only to restart it again in the near
761 dev->power.request = RPM_REQ_NONE;
762 if (!dev->power.timer_autosuspends)
763 pm_runtime_deactivate_timer(dev);
765 if (dev->power.runtime_status == RPM_ACTIVE) {
770 if (dev->power.runtime_status == RPM_RESUMING
771 || dev->power.runtime_status == RPM_SUSPENDING) {
774 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
775 if (dev->power.runtime_status == RPM_SUSPENDING)
776 dev->power.deferred_resume = true;
778 retval = -EINPROGRESS;
782 if (dev->power.irq_safe) {
783 spin_unlock(&dev->power.lock);
787 spin_lock(&dev->power.lock);
791 /* Wait for the operation carried out in parallel with us. */
793 prepare_to_wait(&dev->power.wait_queue, &wait,
794 TASK_UNINTERRUPTIBLE);
795 if (dev->power.runtime_status != RPM_RESUMING
796 && dev->power.runtime_status != RPM_SUSPENDING)
799 spin_unlock_irq(&dev->power.lock);
803 spin_lock_irq(&dev->power.lock);
805 finish_wait(&dev->power.wait_queue, &wait);
810 * See if we can skip waking up the parent. This is safe only if
811 * power.no_callbacks is set, because otherwise we don't know whether
812 * the resume will actually succeed.
814 if (dev->power.no_callbacks && !parent && dev->parent) {
815 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
816 if (dev->parent->power.disable_depth > 0
817 || dev->parent->power.ignore_children
818 || dev->parent->power.runtime_status == RPM_ACTIVE) {
819 atomic_inc(&dev->parent->power.child_count);
820 spin_unlock(&dev->parent->power.lock);
822 goto no_callback; /* Assume success. */
824 spin_unlock(&dev->parent->power.lock);
827 /* Carry out an asynchronous or a synchronous resume. */
828 if (rpmflags & RPM_ASYNC) {
829 dev->power.request = RPM_REQ_RESUME;
830 if (!dev->power.request_pending) {
831 dev->power.request_pending = true;
832 queue_work(pm_wq, &dev->power.work);
838 if (!parent && dev->parent) {
840 * Increment the parent's usage counter and resume it if
841 * necessary. Not needed if dev is irq-safe; then the
842 * parent is permanently resumed.
844 parent = dev->parent;
845 if (dev->power.irq_safe)
847 spin_unlock(&dev->power.lock);
849 pm_runtime_get_noresume(parent);
851 spin_lock(&parent->power.lock);
853 * Resume the parent if it has runtime PM enabled and not been
854 * set to ignore its children.
856 if (!parent->power.disable_depth
857 && !parent->power.ignore_children) {
858 rpm_resume(parent, 0);
859 if (parent->power.runtime_status != RPM_ACTIVE)
862 spin_unlock(&parent->power.lock);
864 spin_lock(&dev->power.lock);
871 if (dev->power.no_callbacks)
872 goto no_callback; /* Assume success. */
874 __update_runtime_status(dev, RPM_RESUMING);
876 callback = RPM_GET_CALLBACK(dev, runtime_resume);
878 dev_pm_disable_wake_irq_check(dev);
879 retval = rpm_callback(callback, dev);
881 __update_runtime_status(dev, RPM_SUSPENDED);
882 pm_runtime_cancel_pending(dev);
883 dev_pm_enable_wake_irq_check(dev, false);
886 __update_runtime_status(dev, RPM_ACTIVE);
887 pm_runtime_mark_last_busy(dev);
889 atomic_inc(&parent->power.child_count);
891 wake_up_all(&dev->power.wait_queue);
894 rpm_idle(dev, RPM_ASYNC);
897 if (parent && !dev->power.irq_safe) {
898 spin_unlock_irq(&dev->power.lock);
900 pm_runtime_put(parent);
902 spin_lock_irq(&dev->power.lock);
905 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
911 * pm_runtime_work - Universal runtime PM work function.
912 * @work: Work structure used for scheduling the execution of this function.
914 * Use @work to get the device object the work is to be done for, determine what
915 * is to be done and execute the appropriate runtime PM function.
917 static void pm_runtime_work(struct work_struct *work)
919 struct device *dev = container_of(work, struct device, power.work);
920 enum rpm_request req;
922 spin_lock_irq(&dev->power.lock);
924 if (!dev->power.request_pending)
927 req = dev->power.request;
928 dev->power.request = RPM_REQ_NONE;
929 dev->power.request_pending = false;
935 rpm_idle(dev, RPM_NOWAIT);
937 case RPM_REQ_SUSPEND:
938 rpm_suspend(dev, RPM_NOWAIT);
940 case RPM_REQ_AUTOSUSPEND:
941 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
944 rpm_resume(dev, RPM_NOWAIT);
949 spin_unlock_irq(&dev->power.lock);
953 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
954 * @timer: hrtimer used by pm_schedule_suspend().
956 * Check if the time is right and queue a suspend request.
958 static enum hrtimer_restart pm_suspend_timer_fn(struct hrtimer *timer)
960 struct device *dev = container_of(timer, struct device, power.suspend_timer);
964 spin_lock_irqsave(&dev->power.lock, flags);
966 expires = dev->power.timer_expires;
968 * If 'expires' is after the current time, we've been called
971 if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
972 dev->power.timer_expires = 0;
973 rpm_suspend(dev, dev->power.timer_autosuspends ?
974 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
977 spin_unlock_irqrestore(&dev->power.lock, flags);
979 return HRTIMER_NORESTART;
983 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
984 * @dev: Device to suspend.
985 * @delay: Time to wait before submitting a suspend request, in milliseconds.
987 int pm_schedule_suspend(struct device *dev, unsigned int delay)
993 spin_lock_irqsave(&dev->power.lock, flags);
996 retval = rpm_suspend(dev, RPM_ASYNC);
1000 retval = rpm_check_suspend_allowed(dev);
1004 /* Other scheduled or pending requests need to be canceled. */
1005 pm_runtime_cancel_pending(dev);
1007 expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC;
1008 dev->power.timer_expires = expires;
1009 dev->power.timer_autosuspends = 0;
1010 hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);
1013 spin_unlock_irqrestore(&dev->power.lock, flags);
1017 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
1020 * __pm_runtime_idle - Entry point for runtime idle operations.
1021 * @dev: Device to send idle notification for.
1022 * @rpmflags: Flag bits.
1024 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1025 * return immediately if it is larger than zero. Then carry out an idle
1026 * notification, either synchronous or asynchronous.
1028 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1029 * or if pm_runtime_irq_safe() has been called.
1031 int __pm_runtime_idle(struct device *dev, int rpmflags)
1033 unsigned long flags;
1036 if (rpmflags & RPM_GET_PUT) {
1037 if (!atomic_dec_and_test(&dev->power.usage_count)) {
1038 trace_rpm_usage_rcuidle(dev, rpmflags);
1043 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1045 spin_lock_irqsave(&dev->power.lock, flags);
1046 retval = rpm_idle(dev, rpmflags);
1047 spin_unlock_irqrestore(&dev->power.lock, flags);
1051 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
1054 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
1055 * @dev: Device to suspend.
1056 * @rpmflags: Flag bits.
1058 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1059 * return immediately if it is larger than zero. Then carry out a suspend,
1060 * either synchronous or asynchronous.
1062 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1063 * or if pm_runtime_irq_safe() has been called.
1065 int __pm_runtime_suspend(struct device *dev, int rpmflags)
1067 unsigned long flags;
1070 if (rpmflags & RPM_GET_PUT) {
1071 if (!atomic_dec_and_test(&dev->power.usage_count)) {
1072 trace_rpm_usage_rcuidle(dev, rpmflags);
1077 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1079 spin_lock_irqsave(&dev->power.lock, flags);
1080 retval = rpm_suspend(dev, rpmflags);
1081 spin_unlock_irqrestore(&dev->power.lock, flags);
1085 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
1088 * __pm_runtime_resume - Entry point for runtime resume operations.
1089 * @dev: Device to resume.
1090 * @rpmflags: Flag bits.
1092 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
1093 * carry out a resume, either synchronous or asynchronous.
1095 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1096 * or if pm_runtime_irq_safe() has been called.
1098 int __pm_runtime_resume(struct device *dev, int rpmflags)
1100 unsigned long flags;
1103 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
1104 dev->power.runtime_status != RPM_ACTIVE);
1106 if (rpmflags & RPM_GET_PUT)
1107 atomic_inc(&dev->power.usage_count);
1109 spin_lock_irqsave(&dev->power.lock, flags);
1110 retval = rpm_resume(dev, rpmflags);
1111 spin_unlock_irqrestore(&dev->power.lock, flags);
1115 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
1118 * pm_runtime_get_if_active - Conditionally bump up device usage counter.
1119 * @dev: Device to handle.
1120 * @ign_usage_count: Whether or not to look at the current usage counter value.
1122 * Return -EINVAL if runtime PM is disabled for @dev.
1124 * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either
1125 * @ign_usage_count is %true or the runtime PM usage counter of @dev is not
1126 * zero, increment the usage counter of @dev and return 1. Otherwise, return 0
1127 * without changing the usage counter.
1129 * If @ign_usage_count is %true, this function can be used to prevent suspending
1130 * the device when its runtime PM status is %RPM_ACTIVE.
1132 * If @ign_usage_count is %false, this function can be used to prevent
1133 * suspending the device when both its runtime PM status is %RPM_ACTIVE and its
1134 * runtime PM usage counter is not zero.
1136 * The caller is responsible for decrementing the runtime PM usage counter of
1137 * @dev after this function has returned a positive value for it.
1139 int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
1141 unsigned long flags;
1144 spin_lock_irqsave(&dev->power.lock, flags);
1145 if (dev->power.disable_depth > 0) {
1147 } else if (dev->power.runtime_status != RPM_ACTIVE) {
1149 } else if (ign_usage_count) {
1151 atomic_inc(&dev->power.usage_count);
1153 retval = atomic_inc_not_zero(&dev->power.usage_count);
1155 trace_rpm_usage_rcuidle(dev, 0);
1156 spin_unlock_irqrestore(&dev->power.lock, flags);
1160 EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
1163 * __pm_runtime_set_status - Set runtime PM status of a device.
1164 * @dev: Device to handle.
1165 * @status: New runtime PM status of the device.
1167 * If runtime PM of the device is disabled or its power.runtime_error field is
1168 * different from zero, the status may be changed either to RPM_ACTIVE, or to
1169 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1170 * However, if the device has a parent and the parent is not active, and the
1171 * parent's power.ignore_children flag is unset, the device's status cannot be
1172 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1174 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1175 * and the device parent's counter of unsuspended children is modified to
1176 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
1177 * notification request for the parent is submitted.
1179 * If @dev has any suppliers (as reflected by device links to them), and @status
1180 * is RPM_ACTIVE, they will be activated upfront and if the activation of one
1181 * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead
1182 * of the @status value) and the suppliers will be deacticated on exit. The
1183 * error returned by the failing supplier activation will be returned in that
1186 int __pm_runtime_set_status(struct device *dev, unsigned int status)
1188 struct device *parent = dev->parent;
1189 bool notify_parent = false;
1192 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1195 spin_lock_irq(&dev->power.lock);
1198 * Prevent PM-runtime from being enabled for the device or return an
1199 * error if it is enabled already and working.
1201 if (dev->power.runtime_error || dev->power.disable_depth)
1202 dev->power.disable_depth++;
1206 spin_unlock_irq(&dev->power.lock);
1212 * If the new status is RPM_ACTIVE, the suppliers can be activated
1213 * upfront regardless of the current status, because next time
1214 * rpm_put_suppliers() runs, the rpm_active refcounts of the links
1215 * involved will be dropped down to one anyway.
1217 if (status == RPM_ACTIVE) {
1218 int idx = device_links_read_lock();
1220 error = rpm_get_suppliers(dev);
1222 status = RPM_SUSPENDED;
1224 device_links_read_unlock(idx);
1227 spin_lock_irq(&dev->power.lock);
1229 if (dev->power.runtime_status == status || !parent)
1232 if (status == RPM_SUSPENDED) {
1233 atomic_add_unless(&parent->power.child_count, -1, 0);
1234 notify_parent = !parent->power.ignore_children;
1236 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1239 * It is invalid to put an active child under a parent that is
1240 * not active, has runtime PM enabled and the
1241 * 'power.ignore_children' flag unset.
1243 if (!parent->power.disable_depth
1244 && !parent->power.ignore_children
1245 && parent->power.runtime_status != RPM_ACTIVE) {
1246 dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1250 } else if (dev->power.runtime_status == RPM_SUSPENDED) {
1251 atomic_inc(&parent->power.child_count);
1254 spin_unlock(&parent->power.lock);
1257 status = RPM_SUSPENDED;
1263 __update_runtime_status(dev, status);
1265 dev->power.runtime_error = 0;
1268 spin_unlock_irq(&dev->power.lock);
1271 pm_request_idle(parent);
1273 if (status == RPM_SUSPENDED) {
1274 int idx = device_links_read_lock();
1276 rpm_put_suppliers(dev);
1278 device_links_read_unlock(idx);
1281 pm_runtime_enable(dev);
1285 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1288 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1289 * @dev: Device to handle.
1291 * Flush all pending requests for the device from pm_wq and wait for all
1292 * runtime PM operations involving the device in progress to complete.
1294 * Should be called under dev->power.lock with interrupts disabled.
1296 static void __pm_runtime_barrier(struct device *dev)
1298 pm_runtime_deactivate_timer(dev);
1300 if (dev->power.request_pending) {
1301 dev->power.request = RPM_REQ_NONE;
1302 spin_unlock_irq(&dev->power.lock);
1304 cancel_work_sync(&dev->power.work);
1306 spin_lock_irq(&dev->power.lock);
1307 dev->power.request_pending = false;
1310 if (dev->power.runtime_status == RPM_SUSPENDING
1311 || dev->power.runtime_status == RPM_RESUMING
1312 || dev->power.idle_notification) {
1315 /* Suspend, wake-up or idle notification in progress. */
1317 prepare_to_wait(&dev->power.wait_queue, &wait,
1318 TASK_UNINTERRUPTIBLE);
1319 if (dev->power.runtime_status != RPM_SUSPENDING
1320 && dev->power.runtime_status != RPM_RESUMING
1321 && !dev->power.idle_notification)
1323 spin_unlock_irq(&dev->power.lock);
1327 spin_lock_irq(&dev->power.lock);
1329 finish_wait(&dev->power.wait_queue, &wait);
1334 * pm_runtime_barrier - Flush pending requests and wait for completions.
1335 * @dev: Device to handle.
1337 * Prevent the device from being suspended by incrementing its usage counter and
1338 * if there's a pending resume request for the device, wake the device up.
1339 * Next, make sure that all pending requests for the device have been flushed
1340 * from pm_wq and wait for all runtime PM operations involving the device in
1341 * progress to complete.
1344 * 1, if there was a resume request pending and the device had to be woken up,
1347 int pm_runtime_barrier(struct device *dev)
1351 pm_runtime_get_noresume(dev);
1352 spin_lock_irq(&dev->power.lock);
1354 if (dev->power.request_pending
1355 && dev->power.request == RPM_REQ_RESUME) {
1360 __pm_runtime_barrier(dev);
1362 spin_unlock_irq(&dev->power.lock);
1363 pm_runtime_put_noidle(dev);
1367 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1370 * __pm_runtime_disable - Disable runtime PM of a device.
1371 * @dev: Device to handle.
1372 * @check_resume: If set, check if there's a resume request for the device.
1374 * Increment power.disable_depth for the device and if it was zero previously,
1375 * cancel all pending runtime PM requests for the device and wait for all
1376 * operations in progress to complete. The device can be either active or
1377 * suspended after its runtime PM has been disabled.
1379 * If @check_resume is set and there's a resume request pending when
1380 * __pm_runtime_disable() is called and power.disable_depth is zero, the
1381 * function will wake up the device before disabling its runtime PM.
1383 void __pm_runtime_disable(struct device *dev, bool check_resume)
1385 spin_lock_irq(&dev->power.lock);
1387 if (dev->power.disable_depth > 0) {
1388 dev->power.disable_depth++;
1393 * Wake up the device if there's a resume request pending, because that
1394 * means there probably is some I/O to process and disabling runtime PM
1395 * shouldn't prevent the device from processing the I/O.
1397 if (check_resume && dev->power.request_pending
1398 && dev->power.request == RPM_REQ_RESUME) {
1400 * Prevent suspends and idle notifications from being carried
1401 * out after we have woken up the device.
1403 pm_runtime_get_noresume(dev);
1407 pm_runtime_put_noidle(dev);
1410 /* Update time accounting before disabling PM-runtime. */
1411 update_pm_runtime_accounting(dev);
1413 if (!dev->power.disable_depth++)
1414 __pm_runtime_barrier(dev);
1417 spin_unlock_irq(&dev->power.lock);
1419 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1422 * pm_runtime_enable - Enable runtime PM of a device.
1423 * @dev: Device to handle.
1425 void pm_runtime_enable(struct device *dev)
1427 unsigned long flags;
1429 spin_lock_irqsave(&dev->power.lock, flags);
1431 if (dev->power.disable_depth > 0) {
1432 dev->power.disable_depth--;
1434 /* About to enable runtime pm, set accounting_timestamp to now */
1435 if (!dev->power.disable_depth)
1436 dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
1438 dev_warn(dev, "Unbalanced %s!\n", __func__);
1441 WARN(!dev->power.disable_depth &&
1442 dev->power.runtime_status == RPM_SUSPENDED &&
1443 !dev->power.ignore_children &&
1444 atomic_read(&dev->power.child_count) > 0,
1445 "Enabling runtime PM for inactive device (%s) with active children\n",
1448 spin_unlock_irqrestore(&dev->power.lock, flags);
1450 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1453 * pm_runtime_forbid - Block runtime PM of a device.
1454 * @dev: Device to handle.
1456 * Increase the device's usage count and clear its power.runtime_auto flag,
1457 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1460 void pm_runtime_forbid(struct device *dev)
1462 spin_lock_irq(&dev->power.lock);
1463 if (!dev->power.runtime_auto)
1466 dev->power.runtime_auto = false;
1467 atomic_inc(&dev->power.usage_count);
1471 spin_unlock_irq(&dev->power.lock);
1473 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1476 * pm_runtime_allow - Unblock runtime PM of a device.
1477 * @dev: Device to handle.
1479 * Decrease the device's usage count and set its power.runtime_auto flag.
1481 void pm_runtime_allow(struct device *dev)
1483 spin_lock_irq(&dev->power.lock);
1484 if (dev->power.runtime_auto)
1487 dev->power.runtime_auto = true;
1488 if (atomic_dec_and_test(&dev->power.usage_count))
1489 rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1491 trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC);
1494 spin_unlock_irq(&dev->power.lock);
1496 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1499 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1500 * @dev: Device to handle.
1502 * Set the power.no_callbacks flag, which tells the PM core that this
1503 * device is power-managed through its parent and has no runtime PM
1504 * callbacks of its own. The runtime sysfs attributes will be removed.
1506 void pm_runtime_no_callbacks(struct device *dev)
1508 spin_lock_irq(&dev->power.lock);
1509 dev->power.no_callbacks = 1;
1510 spin_unlock_irq(&dev->power.lock);
1511 if (device_is_registered(dev))
1512 rpm_sysfs_remove(dev);
1514 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1517 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1518 * @dev: Device to handle
1520 * Set the power.irq_safe flag, which tells the PM core that the
1521 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1522 * always be invoked with the spinlock held and interrupts disabled. It also
1523 * causes the parent's usage counter to be permanently incremented, preventing
1524 * the parent from runtime suspending -- otherwise an irq-safe child might have
1525 * to wait for a non-irq-safe parent.
1527 void pm_runtime_irq_safe(struct device *dev)
1530 pm_runtime_get_sync(dev->parent);
1531 spin_lock_irq(&dev->power.lock);
1532 dev->power.irq_safe = 1;
1533 spin_unlock_irq(&dev->power.lock);
1535 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1538 * update_autosuspend - Handle a change to a device's autosuspend settings.
1539 * @dev: Device to handle.
1540 * @old_delay: The former autosuspend_delay value.
1541 * @old_use: The former use_autosuspend value.
1543 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1544 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1546 * This function must be called under dev->power.lock with interrupts disabled.
1548 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1550 int delay = dev->power.autosuspend_delay;
1552 /* Should runtime suspend be prevented now? */
1553 if (dev->power.use_autosuspend && delay < 0) {
1555 /* If it used to be allowed then prevent it. */
1556 if (!old_use || old_delay >= 0) {
1557 atomic_inc(&dev->power.usage_count);
1560 trace_rpm_usage_rcuidle(dev, 0);
1564 /* Runtime suspend should be allowed now. */
1567 /* If it used to be prevented then allow it. */
1568 if (old_use && old_delay < 0)
1569 atomic_dec(&dev->power.usage_count);
1571 /* Maybe we can autosuspend now. */
1572 rpm_idle(dev, RPM_AUTO);
1577 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1578 * @dev: Device to handle.
1579 * @delay: Value of the new delay in milliseconds.
1581 * Set the device's power.autosuspend_delay value. If it changes to negative
1582 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1583 * changes the other way, allow runtime suspends.
1585 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1587 int old_delay, old_use;
1589 spin_lock_irq(&dev->power.lock);
1590 old_delay = dev->power.autosuspend_delay;
1591 old_use = dev->power.use_autosuspend;
1592 dev->power.autosuspend_delay = delay;
1593 update_autosuspend(dev, old_delay, old_use);
1594 spin_unlock_irq(&dev->power.lock);
1596 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1599 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1600 * @dev: Device to handle.
1601 * @use: New value for use_autosuspend.
1603 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1604 * suspends as needed.
1606 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1608 int old_delay, old_use;
1610 spin_lock_irq(&dev->power.lock);
1611 old_delay = dev->power.autosuspend_delay;
1612 old_use = dev->power.use_autosuspend;
1613 dev->power.use_autosuspend = use;
1614 update_autosuspend(dev, old_delay, old_use);
1615 spin_unlock_irq(&dev->power.lock);
1617 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1620 * pm_runtime_init - Initialize runtime PM fields in given device object.
1621 * @dev: Device object to initialize.
1623 void pm_runtime_init(struct device *dev)
1625 dev->power.runtime_status = RPM_SUSPENDED;
1626 dev->power.idle_notification = false;
1628 dev->power.disable_depth = 1;
1629 atomic_set(&dev->power.usage_count, 0);
1631 dev->power.runtime_error = 0;
1633 atomic_set(&dev->power.child_count, 0);
1634 pm_suspend_ignore_children(dev, false);
1635 dev->power.runtime_auto = true;
1637 dev->power.request_pending = false;
1638 dev->power.request = RPM_REQ_NONE;
1639 dev->power.deferred_resume = false;
1640 dev->power.needs_force_resume = 0;
1641 INIT_WORK(&dev->power.work, pm_runtime_work);
1643 dev->power.timer_expires = 0;
1644 hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1645 dev->power.suspend_timer.function = pm_suspend_timer_fn;
1647 init_waitqueue_head(&dev->power.wait_queue);
1651 * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1652 * @dev: Device object to re-initialize.
1654 void pm_runtime_reinit(struct device *dev)
1656 if (!pm_runtime_enabled(dev)) {
1657 if (dev->power.runtime_status == RPM_ACTIVE)
1658 pm_runtime_set_suspended(dev);
1659 if (dev->power.irq_safe) {
1660 spin_lock_irq(&dev->power.lock);
1661 dev->power.irq_safe = 0;
1662 spin_unlock_irq(&dev->power.lock);
1664 pm_runtime_put(dev->parent);
1670 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1671 * @dev: Device object being removed from device hierarchy.
1673 void pm_runtime_remove(struct device *dev)
1675 __pm_runtime_disable(dev, false);
1676 pm_runtime_reinit(dev);
1680 * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
1681 * @dev: Consumer device.
1683 void pm_runtime_get_suppliers(struct device *dev)
1685 struct device_link *link;
1688 idx = device_links_read_lock();
1690 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1691 device_links_read_lock_held())
1692 if (link->flags & DL_FLAG_PM_RUNTIME) {
1693 link->supplier_preactivated = true;
1694 pm_runtime_get_sync(link->supplier);
1695 refcount_inc(&link->rpm_active);
1698 device_links_read_unlock(idx);
1702 * pm_runtime_put_suppliers - Drop references to supplier devices.
1703 * @dev: Consumer device.
1705 void pm_runtime_put_suppliers(struct device *dev)
1707 struct device_link *link;
1708 unsigned long flags;
1712 idx = device_links_read_lock();
1714 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1715 device_links_read_lock_held())
1716 if (link->supplier_preactivated) {
1717 link->supplier_preactivated = false;
1718 spin_lock_irqsave(&dev->power.lock, flags);
1719 put = pm_runtime_status_suspended(dev) &&
1720 refcount_dec_not_one(&link->rpm_active);
1721 spin_unlock_irqrestore(&dev->power.lock, flags);
1723 pm_runtime_put(link->supplier);
1726 device_links_read_unlock(idx);
1729 void pm_runtime_new_link(struct device *dev)
1731 spin_lock_irq(&dev->power.lock);
1732 dev->power.links_count++;
1733 spin_unlock_irq(&dev->power.lock);
1736 static void pm_runtime_drop_link_count(struct device *dev)
1738 spin_lock_irq(&dev->power.lock);
1739 WARN_ON(dev->power.links_count == 0);
1740 dev->power.links_count--;
1741 spin_unlock_irq(&dev->power.lock);
1745 * pm_runtime_drop_link - Prepare for device link removal.
1746 * @link: Device link going away.
1748 * Drop the link count of the consumer end of @link and decrement the supplier
1749 * device's runtime PM usage counter as many times as needed to drop all of the
1750 * PM runtime reference to it from the consumer.
1752 void pm_runtime_drop_link(struct device_link *link)
1754 if (!(link->flags & DL_FLAG_PM_RUNTIME))
1757 pm_runtime_drop_link_count(link->consumer);
1759 while (refcount_dec_not_one(&link->rpm_active))
1760 pm_runtime_put(link->supplier);
1763 static bool pm_runtime_need_not_resume(struct device *dev)
1765 return atomic_read(&dev->power.usage_count) <= 1 &&
1766 (atomic_read(&dev->power.child_count) == 0 ||
1767 dev->power.ignore_children);
1771 * pm_runtime_force_suspend - Force a device into suspend state if needed.
1772 * @dev: Device to suspend.
1774 * Disable runtime PM so we safely can check the device's runtime PM status and
1775 * if it is active, invoke its ->runtime_suspend callback to suspend it and
1776 * change its runtime PM status field to RPM_SUSPENDED. Also, if the device's
1777 * usage and children counters don't indicate that the device was in use before
1778 * the system-wide transition under way, decrement its parent's children counter
1779 * (if there is a parent). Keep runtime PM disabled to preserve the state
1780 * unless we encounter errors.
1782 * Typically this function may be invoked from a system suspend callback to make
1783 * sure the device is put into low power state and it should only be used during
1784 * system-wide PM transitions to sleep states. It assumes that the analogous
1785 * pm_runtime_force_resume() will be used to resume the device.
1787 int pm_runtime_force_suspend(struct device *dev)
1789 int (*callback)(struct device *);
1792 pm_runtime_disable(dev);
1793 if (pm_runtime_status_suspended(dev))
1796 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1798 ret = callback ? callback(dev) : 0;
1803 * If the device can stay in suspend after the system-wide transition
1804 * to the working state that will follow, drop the children counter of
1805 * its parent, but set its status to RPM_SUSPENDED anyway in case this
1806 * function will be called again for it in the meantime.
1808 if (pm_runtime_need_not_resume(dev)) {
1809 pm_runtime_set_suspended(dev);
1811 __update_runtime_status(dev, RPM_SUSPENDED);
1812 dev->power.needs_force_resume = 1;
1818 pm_runtime_enable(dev);
1821 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1824 * pm_runtime_force_resume - Force a device into resume state if needed.
1825 * @dev: Device to resume.
1827 * Prior invoking this function we expect the user to have brought the device
1828 * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1829 * those actions and bring the device into full power, if it is expected to be
1830 * used on system resume. In the other case, we defer the resume to be managed
1833 * Typically this function may be invoked from a system resume callback.
1835 int pm_runtime_force_resume(struct device *dev)
1837 int (*callback)(struct device *);
1840 if (!pm_runtime_status_suspended(dev) || !dev->power.needs_force_resume)
1844 * The value of the parent's children counter is correct already, so
1845 * just update the status of the device.
1847 __update_runtime_status(dev, RPM_ACTIVE);
1849 callback = RPM_GET_CALLBACK(dev, runtime_resume);
1851 ret = callback ? callback(dev) : 0;
1853 pm_runtime_set_suspended(dev);
1857 pm_runtime_mark_last_busy(dev);
1859 dev->power.needs_force_resume = 0;
1860 pm_runtime_enable(dev);
1863 EXPORT_SYMBOL_GPL(pm_runtime_force_resume);