2 * drivers/base/power/runtime.c - Helper functions for device runtime PM
4 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
7 * This file is released under the GPLv2.
10 #include <linux/sched.h>
11 #include <linux/export.h>
12 #include <linux/pm_runtime.h>
13 #include <trace/events/rpm.h>
16 static int rpm_resume(struct device *dev, int rpmflags);
17 static int rpm_suspend(struct device *dev, int rpmflags);
20 * update_pm_runtime_accounting - Update the time accounting of power states
21 * @dev: Device to update the accounting for
23 * In order to be able to have time accounting of the various power states
24 * (as used by programs such as PowerTOP to show the effectiveness of runtime
25 * PM), we need to track the time spent in each state.
26 * update_pm_runtime_accounting must be called each time before the
27 * runtime_status field is updated, to account the time in the old state
30 void update_pm_runtime_accounting(struct device *dev)
32 unsigned long now = jiffies;
35 delta = now - dev->power.accounting_timestamp;
37 dev->power.accounting_timestamp = now;
39 if (dev->power.disable_depth > 0)
42 if (dev->power.runtime_status == RPM_SUSPENDED)
43 dev->power.suspended_jiffies += delta;
45 dev->power.active_jiffies += delta;
48 static void __update_runtime_status(struct device *dev, enum rpm_status status)
50 update_pm_runtime_accounting(dev);
51 dev->power.runtime_status = status;
55 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
56 * @dev: Device to handle.
58 static void pm_runtime_deactivate_timer(struct device *dev)
60 if (dev->power.timer_expires > 0) {
61 del_timer(&dev->power.suspend_timer);
62 dev->power.timer_expires = 0;
67 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
68 * @dev: Device to handle.
70 static void pm_runtime_cancel_pending(struct device *dev)
72 pm_runtime_deactivate_timer(dev);
74 * In case there's a request pending, make sure its work function will
75 * return without doing anything.
77 dev->power.request = RPM_REQ_NONE;
81 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
82 * @dev: Device to handle.
84 * Compute the autosuspend-delay expiration time based on the device's
85 * power.last_busy time. If the delay has already expired or is disabled
86 * (negative) or the power.use_autosuspend flag isn't set, return 0.
87 * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
89 * This function may be called either with or without dev->power.lock held.
90 * Either way it can be racy, since power.last_busy may be updated at any time.
92 unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
94 int autosuspend_delay;
96 unsigned long last_busy;
97 unsigned long expires = 0;
99 if (!dev->power.use_autosuspend)
102 autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
103 if (autosuspend_delay < 0)
106 last_busy = ACCESS_ONCE(dev->power.last_busy);
107 elapsed = jiffies - last_busy;
109 goto out; /* jiffies has wrapped around. */
112 * If the autosuspend_delay is >= 1 second, align the timer by rounding
113 * up to the nearest second.
115 expires = last_busy + msecs_to_jiffies(autosuspend_delay);
116 if (autosuspend_delay >= 1000)
117 expires = round_jiffies(expires);
119 if (elapsed >= expires - last_busy)
120 expires = 0; /* Already expired. */
125 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
128 * rpm_check_suspend_allowed - Test whether a device may be suspended.
129 * @dev: Device to test.
131 static int rpm_check_suspend_allowed(struct device *dev)
135 if (dev->power.runtime_error)
137 else if (dev->power.disable_depth > 0)
139 else if (atomic_read(&dev->power.usage_count) > 0)
141 else if (!pm_children_suspended(dev))
144 /* Pending resume requests take precedence over suspends. */
145 else if ((dev->power.deferred_resume
146 && dev->power.runtime_status == RPM_SUSPENDING)
147 || (dev->power.request_pending
148 && dev->power.request == RPM_REQ_RESUME))
150 else if (dev->power.runtime_status == RPM_SUSPENDED)
157 * __rpm_callback - Run a given runtime PM callback for a given device.
158 * @cb: Runtime PM callback to run.
159 * @dev: Device to run the callback for.
161 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
162 __releases(&dev->power.lock) __acquires(&dev->power.lock)
166 if (dev->power.irq_safe)
167 spin_unlock(&dev->power.lock);
169 spin_unlock_irq(&dev->power.lock);
173 if (dev->power.irq_safe)
174 spin_lock(&dev->power.lock);
176 spin_lock_irq(&dev->power.lock);
182 * rpm_idle - Notify device bus type if the device can be suspended.
183 * @dev: Device to notify the bus type about.
184 * @rpmflags: Flag bits.
186 * Check if the device's runtime PM status allows it to be suspended. If
187 * another idle notification has been started earlier, return immediately. If
188 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
189 * run the ->runtime_idle() callback directly.
191 * This function must be called under dev->power.lock with interrupts disabled.
193 static int rpm_idle(struct device *dev, int rpmflags)
195 int (*callback)(struct device *);
198 trace_rpm_idle(dev, rpmflags);
199 retval = rpm_check_suspend_allowed(dev);
201 ; /* Conditions are wrong. */
203 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
204 else if (dev->power.runtime_status != RPM_ACTIVE)
208 * Any pending request other than an idle notification takes
209 * precedence over us, except that the timer may be running.
211 else if (dev->power.request_pending &&
212 dev->power.request > RPM_REQ_IDLE)
215 /* Act as though RPM_NOWAIT is always set. */
216 else if (dev->power.idle_notification)
217 retval = -EINPROGRESS;
221 /* Pending requests need to be canceled. */
222 dev->power.request = RPM_REQ_NONE;
224 if (dev->power.no_callbacks) {
225 /* Assume ->runtime_idle() callback would have suspended. */
226 retval = rpm_suspend(dev, rpmflags);
230 /* Carry out an asynchronous or a synchronous idle notification. */
231 if (rpmflags & RPM_ASYNC) {
232 dev->power.request = RPM_REQ_IDLE;
233 if (!dev->power.request_pending) {
234 dev->power.request_pending = true;
235 queue_work(pm_wq, &dev->power.work);
240 dev->power.idle_notification = true;
243 callback = dev->pm_domain->ops.runtime_idle;
244 else if (dev->type && dev->type->pm)
245 callback = dev->type->pm->runtime_idle;
246 else if (dev->class && dev->class->pm)
247 callback = dev->class->pm->runtime_idle;
248 else if (dev->bus && dev->bus->pm)
249 callback = dev->bus->pm->runtime_idle;
254 __rpm_callback(callback, dev);
256 dev->power.idle_notification = false;
257 wake_up_all(&dev->power.wait_queue);
260 trace_rpm_return_int(dev, _THIS_IP_, retval);
265 * rpm_callback - Run a given runtime PM callback for a given device.
266 * @cb: Runtime PM callback to run.
267 * @dev: Device to run the callback for.
269 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
276 retval = __rpm_callback(cb, dev);
278 dev->power.runtime_error = retval;
279 return retval != -EACCES ? retval : -EIO;
283 * rpm_suspend - Carry out runtime suspend of given device.
284 * @dev: Device to suspend.
285 * @rpmflags: Flag bits.
287 * Check if the device's runtime PM status allows it to be suspended.
288 * Cancel a pending idle notification, autosuspend or suspend. If
289 * another suspend has been started earlier, either return immediately
290 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
291 * flags. If the RPM_ASYNC flag is set then queue a suspend request;
292 * otherwise run the ->runtime_suspend() callback directly. When
293 * ->runtime_suspend succeeded, if a deferred resume was requested while
294 * the callback was running then carry it out, otherwise send an idle
295 * notification for its parent (if the suspend succeeded and both
296 * ignore_children of parent->power and irq_safe of dev->power are not set).
297 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
298 * flag is set and the next autosuspend-delay expiration time is in the
299 * future, schedule another autosuspend attempt.
301 * This function must be called under dev->power.lock with interrupts disabled.
303 static int rpm_suspend(struct device *dev, int rpmflags)
304 __releases(&dev->power.lock) __acquires(&dev->power.lock)
306 int (*callback)(struct device *);
307 struct device *parent = NULL;
310 trace_rpm_suspend(dev, rpmflags);
313 retval = rpm_check_suspend_allowed(dev);
316 ; /* Conditions are wrong. */
318 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
319 else if (dev->power.runtime_status == RPM_RESUMING &&
320 !(rpmflags & RPM_ASYNC))
325 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
326 if ((rpmflags & RPM_AUTO)
327 && dev->power.runtime_status != RPM_SUSPENDING) {
328 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
331 /* Pending requests need to be canceled. */
332 dev->power.request = RPM_REQ_NONE;
335 * Optimization: If the timer is already running and is
336 * set to expire at or before the autosuspend delay,
337 * avoid the overhead of resetting it. Just let it
338 * expire; pm_suspend_timer_fn() will take care of the
341 if (!(dev->power.timer_expires && time_before_eq(
342 dev->power.timer_expires, expires))) {
343 dev->power.timer_expires = expires;
344 mod_timer(&dev->power.suspend_timer, expires);
346 dev->power.timer_autosuspends = 1;
351 /* Other scheduled or pending requests need to be canceled. */
352 pm_runtime_cancel_pending(dev);
354 if (dev->power.runtime_status == RPM_SUSPENDING) {
357 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
358 retval = -EINPROGRESS;
362 if (dev->power.irq_safe) {
363 spin_unlock(&dev->power.lock);
367 spin_lock(&dev->power.lock);
371 /* Wait for the other suspend running in parallel with us. */
373 prepare_to_wait(&dev->power.wait_queue, &wait,
374 TASK_UNINTERRUPTIBLE);
375 if (dev->power.runtime_status != RPM_SUSPENDING)
378 spin_unlock_irq(&dev->power.lock);
382 spin_lock_irq(&dev->power.lock);
384 finish_wait(&dev->power.wait_queue, &wait);
388 dev->power.deferred_resume = false;
389 if (dev->power.no_callbacks)
390 goto no_callback; /* Assume success. */
392 /* Carry out an asynchronous or a synchronous suspend. */
393 if (rpmflags & RPM_ASYNC) {
394 dev->power.request = (rpmflags & RPM_AUTO) ?
395 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
396 if (!dev->power.request_pending) {
397 dev->power.request_pending = true;
398 queue_work(pm_wq, &dev->power.work);
403 __update_runtime_status(dev, RPM_SUSPENDING);
406 callback = dev->pm_domain->ops.runtime_suspend;
407 else if (dev->type && dev->type->pm)
408 callback = dev->type->pm->runtime_suspend;
409 else if (dev->class && dev->class->pm)
410 callback = dev->class->pm->runtime_suspend;
411 else if (dev->bus && dev->bus->pm)
412 callback = dev->bus->pm->runtime_suspend;
416 retval = rpm_callback(callback, dev);
418 __update_runtime_status(dev, RPM_ACTIVE);
419 dev->power.deferred_resume = false;
420 if (retval == -EAGAIN || retval == -EBUSY) {
421 dev->power.runtime_error = 0;
424 * If the callback routine failed an autosuspend, and
425 * if the last_busy time has been updated so that there
426 * is a new autosuspend expiration time, automatically
427 * reschedule another autosuspend.
429 if ((rpmflags & RPM_AUTO) &&
430 pm_runtime_autosuspend_expiration(dev) != 0)
433 pm_runtime_cancel_pending(dev);
435 wake_up_all(&dev->power.wait_queue);
439 __update_runtime_status(dev, RPM_SUSPENDED);
440 pm_runtime_deactivate_timer(dev);
443 parent = dev->parent;
444 atomic_add_unless(&parent->power.child_count, -1, 0);
446 wake_up_all(&dev->power.wait_queue);
448 if (dev->power.deferred_resume) {
454 /* Maybe the parent is now able to suspend. */
455 if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
456 spin_unlock(&dev->power.lock);
458 spin_lock(&parent->power.lock);
459 rpm_idle(parent, RPM_ASYNC);
460 spin_unlock(&parent->power.lock);
462 spin_lock(&dev->power.lock);
466 trace_rpm_return_int(dev, _THIS_IP_, retval);
472 * rpm_resume - Carry out runtime resume of given device.
473 * @dev: Device to resume.
474 * @rpmflags: Flag bits.
476 * Check if the device's runtime PM status allows it to be resumed. Cancel
477 * any scheduled or pending requests. If another resume has been started
478 * earlier, either return immediately or wait for it to finish, depending on the
479 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
480 * parallel with this function, either tell the other process to resume after
481 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
482 * flag is set then queue a resume request; otherwise run the
483 * ->runtime_resume() callback directly. Queue an idle notification for the
484 * device if the resume succeeded.
486 * This function must be called under dev->power.lock with interrupts disabled.
488 static int rpm_resume(struct device *dev, int rpmflags)
489 __releases(&dev->power.lock) __acquires(&dev->power.lock)
491 int (*callback)(struct device *);
492 struct device *parent = NULL;
495 trace_rpm_resume(dev, rpmflags);
498 if (dev->power.runtime_error)
500 else if (dev->power.disable_depth > 0)
506 * Other scheduled or pending requests need to be canceled. Small
507 * optimization: If an autosuspend timer is running, leave it running
508 * rather than cancelling it now only to restart it again in the near
511 dev->power.request = RPM_REQ_NONE;
512 if (!dev->power.timer_autosuspends)
513 pm_runtime_deactivate_timer(dev);
515 if (dev->power.runtime_status == RPM_ACTIVE) {
520 if (dev->power.runtime_status == RPM_RESUMING
521 || dev->power.runtime_status == RPM_SUSPENDING) {
524 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
525 if (dev->power.runtime_status == RPM_SUSPENDING)
526 dev->power.deferred_resume = true;
528 retval = -EINPROGRESS;
532 if (dev->power.irq_safe) {
533 spin_unlock(&dev->power.lock);
537 spin_lock(&dev->power.lock);
541 /* Wait for the operation carried out in parallel with us. */
543 prepare_to_wait(&dev->power.wait_queue, &wait,
544 TASK_UNINTERRUPTIBLE);
545 if (dev->power.runtime_status != RPM_RESUMING
546 && dev->power.runtime_status != RPM_SUSPENDING)
549 spin_unlock_irq(&dev->power.lock);
553 spin_lock_irq(&dev->power.lock);
555 finish_wait(&dev->power.wait_queue, &wait);
560 * See if we can skip waking up the parent. This is safe only if
561 * power.no_callbacks is set, because otherwise we don't know whether
562 * the resume will actually succeed.
564 if (dev->power.no_callbacks && !parent && dev->parent) {
565 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
566 if (dev->parent->power.disable_depth > 0
567 || dev->parent->power.ignore_children
568 || dev->parent->power.runtime_status == RPM_ACTIVE) {
569 atomic_inc(&dev->parent->power.child_count);
570 spin_unlock(&dev->parent->power.lock);
571 goto no_callback; /* Assume success. */
573 spin_unlock(&dev->parent->power.lock);
576 /* Carry out an asynchronous or a synchronous resume. */
577 if (rpmflags & RPM_ASYNC) {
578 dev->power.request = RPM_REQ_RESUME;
579 if (!dev->power.request_pending) {
580 dev->power.request_pending = true;
581 queue_work(pm_wq, &dev->power.work);
587 if (!parent && dev->parent) {
589 * Increment the parent's usage counter and resume it if
590 * necessary. Not needed if dev is irq-safe; then the
591 * parent is permanently resumed.
593 parent = dev->parent;
594 if (dev->power.irq_safe)
596 spin_unlock(&dev->power.lock);
598 pm_runtime_get_noresume(parent);
600 spin_lock(&parent->power.lock);
602 * We can resume if the parent's runtime PM is disabled or it
603 * is set to ignore children.
605 if (!parent->power.disable_depth
606 && !parent->power.ignore_children) {
607 rpm_resume(parent, 0);
608 if (parent->power.runtime_status != RPM_ACTIVE)
611 spin_unlock(&parent->power.lock);
613 spin_lock(&dev->power.lock);
620 if (dev->power.no_callbacks)
621 goto no_callback; /* Assume success. */
623 __update_runtime_status(dev, RPM_RESUMING);
626 callback = dev->pm_domain->ops.runtime_resume;
627 else if (dev->type && dev->type->pm)
628 callback = dev->type->pm->runtime_resume;
629 else if (dev->class && dev->class->pm)
630 callback = dev->class->pm->runtime_resume;
631 else if (dev->bus && dev->bus->pm)
632 callback = dev->bus->pm->runtime_resume;
636 retval = rpm_callback(callback, dev);
638 __update_runtime_status(dev, RPM_SUSPENDED);
639 pm_runtime_cancel_pending(dev);
642 __update_runtime_status(dev, RPM_ACTIVE);
644 atomic_inc(&parent->power.child_count);
646 wake_up_all(&dev->power.wait_queue);
649 rpm_idle(dev, RPM_ASYNC);
652 if (parent && !dev->power.irq_safe) {
653 spin_unlock_irq(&dev->power.lock);
655 pm_runtime_put(parent);
657 spin_lock_irq(&dev->power.lock);
660 trace_rpm_return_int(dev, _THIS_IP_, retval);
666 * pm_runtime_work - Universal runtime PM work function.
667 * @work: Work structure used for scheduling the execution of this function.
669 * Use @work to get the device object the work is to be done for, determine what
670 * is to be done and execute the appropriate runtime PM function.
672 static void pm_runtime_work(struct work_struct *work)
674 struct device *dev = container_of(work, struct device, power.work);
675 enum rpm_request req;
677 spin_lock_irq(&dev->power.lock);
679 if (!dev->power.request_pending)
682 req = dev->power.request;
683 dev->power.request = RPM_REQ_NONE;
684 dev->power.request_pending = false;
690 rpm_idle(dev, RPM_NOWAIT);
692 case RPM_REQ_SUSPEND:
693 rpm_suspend(dev, RPM_NOWAIT);
695 case RPM_REQ_AUTOSUSPEND:
696 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
699 rpm_resume(dev, RPM_NOWAIT);
704 spin_unlock_irq(&dev->power.lock);
708 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
709 * @data: Device pointer passed by pm_schedule_suspend().
711 * Check if the time is right and queue a suspend request.
713 static void pm_suspend_timer_fn(unsigned long data)
715 struct device *dev = (struct device *)data;
717 unsigned long expires;
719 spin_lock_irqsave(&dev->power.lock, flags);
721 expires = dev->power.timer_expires;
722 /* If 'expire' is after 'jiffies' we've been called too early. */
723 if (expires > 0 && !time_after(expires, jiffies)) {
724 dev->power.timer_expires = 0;
725 rpm_suspend(dev, dev->power.timer_autosuspends ?
726 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
729 spin_unlock_irqrestore(&dev->power.lock, flags);
733 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
734 * @dev: Device to suspend.
735 * @delay: Time to wait before submitting a suspend request, in milliseconds.
737 int pm_schedule_suspend(struct device *dev, unsigned int delay)
742 spin_lock_irqsave(&dev->power.lock, flags);
745 retval = rpm_suspend(dev, RPM_ASYNC);
749 retval = rpm_check_suspend_allowed(dev);
753 /* Other scheduled or pending requests need to be canceled. */
754 pm_runtime_cancel_pending(dev);
756 dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
757 dev->power.timer_expires += !dev->power.timer_expires;
758 dev->power.timer_autosuspends = 0;
759 mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
762 spin_unlock_irqrestore(&dev->power.lock, flags);
766 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
769 * __pm_runtime_idle - Entry point for runtime idle operations.
770 * @dev: Device to send idle notification for.
771 * @rpmflags: Flag bits.
773 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
774 * return immediately if it is larger than zero. Then carry out an idle
775 * notification, either synchronous or asynchronous.
777 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
778 * or if pm_runtime_irq_safe() has been called.
780 int __pm_runtime_idle(struct device *dev, int rpmflags)
785 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
787 if (rpmflags & RPM_GET_PUT) {
788 if (!atomic_dec_and_test(&dev->power.usage_count))
792 spin_lock_irqsave(&dev->power.lock, flags);
793 retval = rpm_idle(dev, rpmflags);
794 spin_unlock_irqrestore(&dev->power.lock, flags);
798 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
801 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
802 * @dev: Device to suspend.
803 * @rpmflags: Flag bits.
805 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
806 * return immediately if it is larger than zero. Then carry out a suspend,
807 * either synchronous or asynchronous.
809 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
810 * or if pm_runtime_irq_safe() has been called.
812 int __pm_runtime_suspend(struct device *dev, int rpmflags)
817 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
819 if (rpmflags & RPM_GET_PUT) {
820 if (!atomic_dec_and_test(&dev->power.usage_count))
824 spin_lock_irqsave(&dev->power.lock, flags);
825 retval = rpm_suspend(dev, rpmflags);
826 spin_unlock_irqrestore(&dev->power.lock, flags);
830 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
833 * __pm_runtime_resume - Entry point for runtime resume operations.
834 * @dev: Device to resume.
835 * @rpmflags: Flag bits.
837 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
838 * carry out a resume, either synchronous or asynchronous.
840 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
841 * or if pm_runtime_irq_safe() has been called.
843 int __pm_runtime_resume(struct device *dev, int rpmflags)
848 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
850 if (rpmflags & RPM_GET_PUT)
851 atomic_inc(&dev->power.usage_count);
853 spin_lock_irqsave(&dev->power.lock, flags);
854 retval = rpm_resume(dev, rpmflags);
855 spin_unlock_irqrestore(&dev->power.lock, flags);
859 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
862 * __pm_runtime_set_status - Set runtime PM status of a device.
863 * @dev: Device to handle.
864 * @status: New runtime PM status of the device.
866 * If runtime PM of the device is disabled or its power.runtime_error field is
867 * different from zero, the status may be changed either to RPM_ACTIVE, or to
868 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
869 * However, if the device has a parent and the parent is not active, and the
870 * parent's power.ignore_children flag is unset, the device's status cannot be
871 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
873 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
874 * and the device parent's counter of unsuspended children is modified to
875 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
876 * notification request for the parent is submitted.
878 int __pm_runtime_set_status(struct device *dev, unsigned int status)
880 struct device *parent = dev->parent;
882 bool notify_parent = false;
885 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
888 spin_lock_irqsave(&dev->power.lock, flags);
890 if (!dev->power.runtime_error && !dev->power.disable_depth) {
895 if (dev->power.runtime_status == status)
898 if (status == RPM_SUSPENDED) {
899 /* It always is possible to set the status to 'suspended'. */
901 atomic_add_unless(&parent->power.child_count, -1, 0);
902 notify_parent = !parent->power.ignore_children;
908 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
911 * It is invalid to put an active child under a parent that is
912 * not active, has runtime PM enabled and the
913 * 'power.ignore_children' flag unset.
915 if (!parent->power.disable_depth
916 && !parent->power.ignore_children
917 && parent->power.runtime_status != RPM_ACTIVE)
919 else if (dev->power.runtime_status == RPM_SUSPENDED)
920 atomic_inc(&parent->power.child_count);
922 spin_unlock(&parent->power.lock);
929 __update_runtime_status(dev, status);
930 dev->power.runtime_error = 0;
932 spin_unlock_irqrestore(&dev->power.lock, flags);
935 pm_request_idle(parent);
939 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
942 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
943 * @dev: Device to handle.
945 * Flush all pending requests for the device from pm_wq and wait for all
946 * runtime PM operations involving the device in progress to complete.
948 * Should be called under dev->power.lock with interrupts disabled.
950 static void __pm_runtime_barrier(struct device *dev)
952 pm_runtime_deactivate_timer(dev);
954 if (dev->power.request_pending) {
955 dev->power.request = RPM_REQ_NONE;
956 spin_unlock_irq(&dev->power.lock);
958 cancel_work_sync(&dev->power.work);
960 spin_lock_irq(&dev->power.lock);
961 dev->power.request_pending = false;
964 if (dev->power.runtime_status == RPM_SUSPENDING
965 || dev->power.runtime_status == RPM_RESUMING
966 || dev->power.idle_notification) {
969 /* Suspend, wake-up or idle notification in progress. */
971 prepare_to_wait(&dev->power.wait_queue, &wait,
972 TASK_UNINTERRUPTIBLE);
973 if (dev->power.runtime_status != RPM_SUSPENDING
974 && dev->power.runtime_status != RPM_RESUMING
975 && !dev->power.idle_notification)
977 spin_unlock_irq(&dev->power.lock);
981 spin_lock_irq(&dev->power.lock);
983 finish_wait(&dev->power.wait_queue, &wait);
988 * pm_runtime_barrier - Flush pending requests and wait for completions.
989 * @dev: Device to handle.
991 * Prevent the device from being suspended by incrementing its usage counter and
992 * if there's a pending resume request for the device, wake the device up.
993 * Next, make sure that all pending requests for the device have been flushed
994 * from pm_wq and wait for all runtime PM operations involving the device in
995 * progress to complete.
998 * 1, if there was a resume request pending and the device had to be woken up,
1001 int pm_runtime_barrier(struct device *dev)
1005 pm_runtime_get_noresume(dev);
1006 spin_lock_irq(&dev->power.lock);
1008 if (dev->power.request_pending
1009 && dev->power.request == RPM_REQ_RESUME) {
1014 __pm_runtime_barrier(dev);
1016 spin_unlock_irq(&dev->power.lock);
1017 pm_runtime_put_noidle(dev);
1021 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1024 * __pm_runtime_disable - Disable runtime PM of a device.
1025 * @dev: Device to handle.
1026 * @check_resume: If set, check if there's a resume request for the device.
1028 * Increment power.disable_depth for the device and if was zero previously,
1029 * cancel all pending runtime PM requests for the device and wait for all
1030 * operations in progress to complete. The device can be either active or
1031 * suspended after its runtime PM has been disabled.
1033 * If @check_resume is set and there's a resume request pending when
1034 * __pm_runtime_disable() is called and power.disable_depth is zero, the
1035 * function will wake up the device before disabling its runtime PM.
1037 void __pm_runtime_disable(struct device *dev, bool check_resume)
1039 spin_lock_irq(&dev->power.lock);
1041 if (dev->power.disable_depth > 0) {
1042 dev->power.disable_depth++;
1047 * Wake up the device if there's a resume request pending, because that
1048 * means there probably is some I/O to process and disabling runtime PM
1049 * shouldn't prevent the device from processing the I/O.
1051 if (check_resume && dev->power.request_pending
1052 && dev->power.request == RPM_REQ_RESUME) {
1054 * Prevent suspends and idle notifications from being carried
1055 * out after we have woken up the device.
1057 pm_runtime_get_noresume(dev);
1061 pm_runtime_put_noidle(dev);
1064 if (!dev->power.disable_depth++)
1065 __pm_runtime_barrier(dev);
1068 spin_unlock_irq(&dev->power.lock);
1070 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1073 * pm_runtime_enable - Enable runtime PM of a device.
1074 * @dev: Device to handle.
1076 void pm_runtime_enable(struct device *dev)
1078 unsigned long flags;
1080 spin_lock_irqsave(&dev->power.lock, flags);
1082 if (dev->power.disable_depth > 0)
1083 dev->power.disable_depth--;
1085 dev_warn(dev, "Unbalanced %s!\n", __func__);
1087 spin_unlock_irqrestore(&dev->power.lock, flags);
1089 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1092 * pm_runtime_forbid - Block runtime PM of a device.
1093 * @dev: Device to handle.
1095 * Increase the device's usage count and clear its power.runtime_auto flag,
1096 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1099 void pm_runtime_forbid(struct device *dev)
1101 spin_lock_irq(&dev->power.lock);
1102 if (!dev->power.runtime_auto)
1105 dev->power.runtime_auto = false;
1106 atomic_inc(&dev->power.usage_count);
1110 spin_unlock_irq(&dev->power.lock);
1112 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1115 * pm_runtime_allow - Unblock runtime PM of a device.
1116 * @dev: Device to handle.
1118 * Decrease the device's usage count and set its power.runtime_auto flag.
1120 void pm_runtime_allow(struct device *dev)
1122 spin_lock_irq(&dev->power.lock);
1123 if (dev->power.runtime_auto)
1126 dev->power.runtime_auto = true;
1127 if (atomic_dec_and_test(&dev->power.usage_count))
1128 rpm_idle(dev, RPM_AUTO);
1131 spin_unlock_irq(&dev->power.lock);
1133 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1136 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1137 * @dev: Device to handle.
1139 * Set the power.no_callbacks flag, which tells the PM core that this
1140 * device is power-managed through its parent and has no runtime PM
1141 * callbacks of its own. The runtime sysfs attributes will be removed.
1143 void pm_runtime_no_callbacks(struct device *dev)
1145 spin_lock_irq(&dev->power.lock);
1146 dev->power.no_callbacks = 1;
1147 spin_unlock_irq(&dev->power.lock);
1148 if (device_is_registered(dev))
1149 rpm_sysfs_remove(dev);
1151 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1154 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1155 * @dev: Device to handle
1157 * Set the power.irq_safe flag, which tells the PM core that the
1158 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1159 * always be invoked with the spinlock held and interrupts disabled. It also
1160 * causes the parent's usage counter to be permanently incremented, preventing
1161 * the parent from runtime suspending -- otherwise an irq-safe child might have
1162 * to wait for a non-irq-safe parent.
1164 void pm_runtime_irq_safe(struct device *dev)
1167 pm_runtime_get_sync(dev->parent);
1168 spin_lock_irq(&dev->power.lock);
1169 dev->power.irq_safe = 1;
1170 spin_unlock_irq(&dev->power.lock);
1172 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1175 * update_autosuspend - Handle a change to a device's autosuspend settings.
1176 * @dev: Device to handle.
1177 * @old_delay: The former autosuspend_delay value.
1178 * @old_use: The former use_autosuspend value.
1180 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1181 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1183 * This function must be called under dev->power.lock with interrupts disabled.
1185 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1187 int delay = dev->power.autosuspend_delay;
1189 /* Should runtime suspend be prevented now? */
1190 if (dev->power.use_autosuspend && delay < 0) {
1192 /* If it used to be allowed then prevent it. */
1193 if (!old_use || old_delay >= 0) {
1194 atomic_inc(&dev->power.usage_count);
1199 /* Runtime suspend should be allowed now. */
1202 /* If it used to be prevented then allow it. */
1203 if (old_use && old_delay < 0)
1204 atomic_dec(&dev->power.usage_count);
1206 /* Maybe we can autosuspend now. */
1207 rpm_idle(dev, RPM_AUTO);
1212 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1213 * @dev: Device to handle.
1214 * @delay: Value of the new delay in milliseconds.
1216 * Set the device's power.autosuspend_delay value. If it changes to negative
1217 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1218 * changes the other way, allow runtime suspends.
1220 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1222 int old_delay, old_use;
1224 spin_lock_irq(&dev->power.lock);
1225 old_delay = dev->power.autosuspend_delay;
1226 old_use = dev->power.use_autosuspend;
1227 dev->power.autosuspend_delay = delay;
1228 update_autosuspend(dev, old_delay, old_use);
1229 spin_unlock_irq(&dev->power.lock);
1231 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1234 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1235 * @dev: Device to handle.
1236 * @use: New value for use_autosuspend.
1238 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1239 * suspends as needed.
1241 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1243 int old_delay, old_use;
1245 spin_lock_irq(&dev->power.lock);
1246 old_delay = dev->power.autosuspend_delay;
1247 old_use = dev->power.use_autosuspend;
1248 dev->power.use_autosuspend = use;
1249 update_autosuspend(dev, old_delay, old_use);
1250 spin_unlock_irq(&dev->power.lock);
1252 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1255 * pm_runtime_init - Initialize runtime PM fields in given device object.
1256 * @dev: Device object to initialize.
1258 void pm_runtime_init(struct device *dev)
1260 dev->power.runtime_status = RPM_SUSPENDED;
1261 dev->power.idle_notification = false;
1263 dev->power.disable_depth = 1;
1264 atomic_set(&dev->power.usage_count, 0);
1266 dev->power.runtime_error = 0;
1268 atomic_set(&dev->power.child_count, 0);
1269 pm_suspend_ignore_children(dev, false);
1270 dev->power.runtime_auto = true;
1272 dev->power.request_pending = false;
1273 dev->power.request = RPM_REQ_NONE;
1274 dev->power.deferred_resume = false;
1275 dev->power.accounting_timestamp = jiffies;
1276 INIT_WORK(&dev->power.work, pm_runtime_work);
1278 dev->power.timer_expires = 0;
1279 setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1280 (unsigned long)dev);
1282 init_waitqueue_head(&dev->power.wait_queue);
1286 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1287 * @dev: Device object being removed from device hierarchy.
1289 void pm_runtime_remove(struct device *dev)
1291 __pm_runtime_disable(dev, false);
1293 /* Change the status back to 'suspended' to match the initial status. */
1294 if (dev->power.runtime_status == RPM_ACTIVE)
1295 pm_runtime_set_suspended(dev);
1296 if (dev->power.irq_safe && dev->parent)
1297 pm_runtime_put_sync(dev->parent);