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1/*
2 * drivers/base/power/runtime.c - Helper functions for device runtime PM
3 *
4 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
6 *
7 * This file is released under the GPLv2.
8 */
9
10#include <linux/sched.h>
11#include <linux/pm_runtime.h>
12#include "power.h"
13
14static int rpm_resume(struct device *dev, int rpmflags);
15static int rpm_suspend(struct device *dev, int rpmflags);
16
17/**
18 * update_pm_runtime_accounting - Update the time accounting of power states
19 * @dev: Device to update the accounting for
20 *
21 * In order to be able to have time accounting of the various power states
22 * (as used by programs such as PowerTOP to show the effectiveness of runtime
23 * PM), we need to track the time spent in each state.
24 * update_pm_runtime_accounting must be called each time before the
25 * runtime_status field is updated, to account the time in the old state
26 * correctly.
27 */
28void update_pm_runtime_accounting(struct device *dev)
29{
30 unsigned long now = jiffies;
31 int delta;
32
33 delta = now - dev->power.accounting_timestamp;
34
35 if (delta < 0)
36 delta = 0;
37
38 dev->power.accounting_timestamp = now;
39
40 if (dev->power.disable_depth > 0)
41 return;
42
43 if (dev->power.runtime_status == RPM_SUSPENDED)
44 dev->power.suspended_jiffies += delta;
45 else
46 dev->power.active_jiffies += delta;
47}
48
49static void __update_runtime_status(struct device *dev, enum rpm_status status)
50{
51 update_pm_runtime_accounting(dev);
52 dev->power.runtime_status = status;
53}
54
55/**
56 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
57 * @dev: Device to handle.
58 */
59static void pm_runtime_deactivate_timer(struct device *dev)
60{
61 if (dev->power.timer_expires > 0) {
62 del_timer(&dev->power.suspend_timer);
63 dev->power.timer_expires = 0;
64 }
65}
66
67/**
68 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
69 * @dev: Device to handle.
70 */
71static void pm_runtime_cancel_pending(struct device *dev)
72{
73 pm_runtime_deactivate_timer(dev);
74 /*
75 * In case there's a request pending, make sure its work function will
76 * return without doing anything.
77 */
78 dev->power.request = RPM_REQ_NONE;
79}
80
81/*
82 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
83 * @dev: Device to handle.
84 *
85 * Compute the autosuspend-delay expiration time based on the device's
86 * power.last_busy time. If the delay has already expired or is disabled
87 * (negative) or the power.use_autosuspend flag isn't set, return 0.
88 * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
89 *
90 * This function may be called either with or without dev->power.lock held.
91 * Either way it can be racy, since power.last_busy may be updated at any time.
92 */
93unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
94{
95 int autosuspend_delay;
96 long elapsed;
97 unsigned long last_busy;
98 unsigned long expires = 0;
99
100 if (!dev->power.use_autosuspend)
101 goto out;
102
103 autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
104 if (autosuspend_delay < 0)
105 goto out;
106
107 last_busy = ACCESS_ONCE(dev->power.last_busy);
108 elapsed = jiffies - last_busy;
109 if (elapsed < 0)
110 goto out; /* jiffies has wrapped around. */
111
112 /*
113 * If the autosuspend_delay is >= 1 second, align the timer by rounding
114 * up to the nearest second.
115 */
116 expires = last_busy + msecs_to_jiffies(autosuspend_delay);
117 if (autosuspend_delay >= 1000)
118 expires = round_jiffies(expires);
119 expires += !expires;
120 if (elapsed >= expires - last_busy)
121 expires = 0; /* Already expired. */
122
123 out:
124 return expires;
125}
126EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
127
128/**
129 * rpm_check_suspend_allowed - Test whether a device may be suspended.
130 * @dev: Device to test.
131 */
132static int rpm_check_suspend_allowed(struct device *dev)
133{
134 int retval = 0;
135
136 if (dev->power.runtime_error)
137 retval = -EINVAL;
138 else if (dev->power.disable_depth > 0)
139 retval = -EACCES;
140 else if (atomic_read(&dev->power.usage_count) > 0)
141 retval = -EAGAIN;
142 else if (!pm_children_suspended(dev))
143 retval = -EBUSY;
144
145 /* Pending resume requests take precedence over suspends. */
146 else if ((dev->power.deferred_resume
147 && dev->power.runtime_status == RPM_SUSPENDING)
148 || (dev->power.request_pending
149 && dev->power.request == RPM_REQ_RESUME))
150 retval = -EAGAIN;
151 else if (dev->power.runtime_status == RPM_SUSPENDED)
152 retval = 1;
153
154 return retval;
155}
156
157/**
158 * rpm_idle - Notify device bus type if the device can be suspended.
159 * @dev: Device to notify the bus type about.
160 * @rpmflags: Flag bits.
161 *
162 * Check if the device's runtime PM status allows it to be suspended. If
163 * another idle notification has been started earlier, return immediately. If
164 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
165 * run the ->runtime_idle() callback directly.
166 *
167 * This function must be called under dev->power.lock with interrupts disabled.
168 */
169static int rpm_idle(struct device *dev, int rpmflags)
170{
171 int (*callback)(struct device *);
172 int retval;
173
174 retval = rpm_check_suspend_allowed(dev);
175 if (retval < 0)
176 ; /* Conditions are wrong. */
177
178 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
179 else if (dev->power.runtime_status != RPM_ACTIVE)
180 retval = -EAGAIN;
181
182 /*
183 * Any pending request other than an idle notification takes
184 * precedence over us, except that the timer may be running.
185 */
186 else if (dev->power.request_pending &&
187 dev->power.request > RPM_REQ_IDLE)
188 retval = -EAGAIN;
189
190 /* Act as though RPM_NOWAIT is always set. */
191 else if (dev->power.idle_notification)
192 retval = -EINPROGRESS;
193 if (retval)
194 goto out;
195
196 /* Pending requests need to be canceled. */
197 dev->power.request = RPM_REQ_NONE;
198
199 if (dev->power.no_callbacks) {
200 /* Assume ->runtime_idle() callback would have suspended. */
201 retval = rpm_suspend(dev, rpmflags);
202 goto out;
203 }
204
205 /* Carry out an asynchronous or a synchronous idle notification. */
206 if (rpmflags & RPM_ASYNC) {
207 dev->power.request = RPM_REQ_IDLE;
208 if (!dev->power.request_pending) {
209 dev->power.request_pending = true;
210 queue_work(pm_wq, &dev->power.work);
211 }
212 goto out;
213 }
214
215 dev->power.idle_notification = true;
216
217 if (dev->pm_domain)
218 callback = dev->pm_domain->ops.runtime_idle;
219 else if (dev->type && dev->type->pm)
220 callback = dev->type->pm->runtime_idle;
221 else if (dev->class && dev->class->pm)
222 callback = dev->class->pm->runtime_idle;
223 else if (dev->bus && dev->bus->pm)
224 callback = dev->bus->pm->runtime_idle;
225 else
226 callback = NULL;
227
228 if (callback) {
229 if (dev->power.irq_safe)
230 spin_unlock(&dev->power.lock);
231 else
232 spin_unlock_irq(&dev->power.lock);
233
234 callback(dev);
235
236 if (dev->power.irq_safe)
237 spin_lock(&dev->power.lock);
238 else
239 spin_lock_irq(&dev->power.lock);
240 }
241
242 dev->power.idle_notification = false;
243 wake_up_all(&dev->power.wait_queue);
244
245 out:
246 return retval;
247}
248
249/**
250 * rpm_callback - Run a given runtime PM callback for a given device.
251 * @cb: Runtime PM callback to run.
252 * @dev: Device to run the callback for.
253 */
254static int rpm_callback(int (*cb)(struct device *), struct device *dev)
255 __releases(&dev->power.lock) __acquires(&dev->power.lock)
256{
257 int retval;
258
259 if (!cb)
260 return -ENOSYS;
261
262 if (dev->power.irq_safe) {
263 retval = cb(dev);
264 } else {
265 spin_unlock_irq(&dev->power.lock);
266
267 retval = cb(dev);
268
269 spin_lock_irq(&dev->power.lock);
270 }
271 dev->power.runtime_error = retval;
272 return retval != -EACCES ? retval : -EIO;
273}
274
275/**
276 * rpm_suspend - Carry out runtime suspend of given device.
277 * @dev: Device to suspend.
278 * @rpmflags: Flag bits.
279 *
280 * Check if the device's runtime PM status allows it to be suspended. If
281 * another suspend has been started earlier, either return immediately or wait
282 * for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC flags. Cancel a
283 * pending idle notification. If the RPM_ASYNC flag is set then queue a
284 * suspend request; otherwise run the ->runtime_suspend() callback directly.
285 * If a deferred resume was requested while the callback was running then carry
286 * it out; otherwise send an idle notification for the device (if the suspend
287 * failed) or for its parent (if the suspend succeeded).
288 *
289 * This function must be called under dev->power.lock with interrupts disabled.
290 */
291static int rpm_suspend(struct device *dev, int rpmflags)
292 __releases(&dev->power.lock) __acquires(&dev->power.lock)
293{
294 int (*callback)(struct device *);
295 struct device *parent = NULL;
296 int retval;
297
298 dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
299
300 repeat:
301 retval = rpm_check_suspend_allowed(dev);
302
303 if (retval < 0)
304 ; /* Conditions are wrong. */
305
306 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
307 else if (dev->power.runtime_status == RPM_RESUMING &&
308 !(rpmflags & RPM_ASYNC))
309 retval = -EAGAIN;
310 if (retval)
311 goto out;
312
313 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
314 if ((rpmflags & RPM_AUTO)
315 && dev->power.runtime_status != RPM_SUSPENDING) {
316 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
317
318 if (expires != 0) {
319 /* Pending requests need to be canceled. */
320 dev->power.request = RPM_REQ_NONE;
321
322 /*
323 * Optimization: If the timer is already running and is
324 * set to expire at or before the autosuspend delay,
325 * avoid the overhead of resetting it. Just let it
326 * expire; pm_suspend_timer_fn() will take care of the
327 * rest.
328 */
329 if (!(dev->power.timer_expires && time_before_eq(
330 dev->power.timer_expires, expires))) {
331 dev->power.timer_expires = expires;
332 mod_timer(&dev->power.suspend_timer, expires);
333 }
334 dev->power.timer_autosuspends = 1;
335 goto out;
336 }
337 }
338
339 /* Other scheduled or pending requests need to be canceled. */
340 pm_runtime_cancel_pending(dev);
341
342 if (dev->power.runtime_status == RPM_SUSPENDING) {
343 DEFINE_WAIT(wait);
344
345 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
346 retval = -EINPROGRESS;
347 goto out;
348 }
349
350 /* Wait for the other suspend running in parallel with us. */
351 for (;;) {
352 prepare_to_wait(&dev->power.wait_queue, &wait,
353 TASK_UNINTERRUPTIBLE);
354 if (dev->power.runtime_status != RPM_SUSPENDING)
355 break;
356
357 spin_unlock_irq(&dev->power.lock);
358
359 schedule();
360
361 spin_lock_irq(&dev->power.lock);
362 }
363 finish_wait(&dev->power.wait_queue, &wait);
364 goto repeat;
365 }
366
367 dev->power.deferred_resume = false;
368 if (dev->power.no_callbacks)
369 goto no_callback; /* Assume success. */
370
371 /* Carry out an asynchronous or a synchronous suspend. */
372 if (rpmflags & RPM_ASYNC) {
373 dev->power.request = (rpmflags & RPM_AUTO) ?
374 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
375 if (!dev->power.request_pending) {
376 dev->power.request_pending = true;
377 queue_work(pm_wq, &dev->power.work);
378 }
379 goto out;
380 }
381
382 __update_runtime_status(dev, RPM_SUSPENDING);
383
384 if (dev->pm_domain)
385 callback = dev->pm_domain->ops.runtime_suspend;
386 else if (dev->type && dev->type->pm)
387 callback = dev->type->pm->runtime_suspend;
388 else if (dev->class && dev->class->pm)
389 callback = dev->class->pm->runtime_suspend;
390 else if (dev->bus && dev->bus->pm)
391 callback = dev->bus->pm->runtime_suspend;
392 else
393 callback = NULL;
394
395 retval = rpm_callback(callback, dev);
396 if (retval) {
397 __update_runtime_status(dev, RPM_ACTIVE);
398 dev->power.deferred_resume = false;
399 if (retval == -EAGAIN || retval == -EBUSY)
400 dev->power.runtime_error = 0;
401 else
402 pm_runtime_cancel_pending(dev);
403 } else {
404 no_callback:
405 __update_runtime_status(dev, RPM_SUSPENDED);
406 pm_runtime_deactivate_timer(dev);
407
408 if (dev->parent) {
409 parent = dev->parent;
410 atomic_add_unless(&parent->power.child_count, -1, 0);
411 }
412 }
413 wake_up_all(&dev->power.wait_queue);
414
415 if (dev->power.deferred_resume) {
416 rpm_resume(dev, 0);
417 retval = -EAGAIN;
418 goto out;
419 }
420
421 /* Maybe the parent is now able to suspend. */
422 if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
423 spin_unlock(&dev->power.lock);
424
425 spin_lock(&parent->power.lock);
426 rpm_idle(parent, RPM_ASYNC);
427 spin_unlock(&parent->power.lock);
428
429 spin_lock(&dev->power.lock);
430 }
431
432 out:
433 dev_dbg(dev, "%s returns %d\n", __func__, retval);
434
435 return retval;
436}
437
438/**
439 * rpm_resume - Carry out runtime resume of given device.
440 * @dev: Device to resume.
441 * @rpmflags: Flag bits.
442 *
443 * Check if the device's runtime PM status allows it to be resumed. Cancel
444 * any scheduled or pending requests. If another resume has been started
445 * earlier, either return immediately or wait for it to finish, depending on the
446 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
447 * parallel with this function, either tell the other process to resume after
448 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
449 * flag is set then queue a resume request; otherwise run the
450 * ->runtime_resume() callback directly. Queue an idle notification for the
451 * device if the resume succeeded.
452 *
453 * This function must be called under dev->power.lock with interrupts disabled.
454 */
455static int rpm_resume(struct device *dev, int rpmflags)
456 __releases(&dev->power.lock) __acquires(&dev->power.lock)
457{
458 int (*callback)(struct device *);
459 struct device *parent = NULL;
460 int retval = 0;
461
462 dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
463
464 repeat:
465 if (dev->power.runtime_error)
466 retval = -EINVAL;
467 else if (dev->power.disable_depth > 0)
468 retval = -EACCES;
469 if (retval)
470 goto out;
471
472 /*
473 * Other scheduled or pending requests need to be canceled. Small
474 * optimization: If an autosuspend timer is running, leave it running
475 * rather than cancelling it now only to restart it again in the near
476 * future.
477 */
478 dev->power.request = RPM_REQ_NONE;
479 if (!dev->power.timer_autosuspends)
480 pm_runtime_deactivate_timer(dev);
481
482 if (dev->power.runtime_status == RPM_ACTIVE) {
483 retval = 1;
484 goto out;
485 }
486
487 if (dev->power.runtime_status == RPM_RESUMING
488 || dev->power.runtime_status == RPM_SUSPENDING) {
489 DEFINE_WAIT(wait);
490
491 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
492 if (dev->power.runtime_status == RPM_SUSPENDING)
493 dev->power.deferred_resume = true;
494 else
495 retval = -EINPROGRESS;
496 goto out;
497 }
498
499 /* Wait for the operation carried out in parallel with us. */
500 for (;;) {
501 prepare_to_wait(&dev->power.wait_queue, &wait,
502 TASK_UNINTERRUPTIBLE);
503 if (dev->power.runtime_status != RPM_RESUMING
504 && dev->power.runtime_status != RPM_SUSPENDING)
505 break;
506
507 spin_unlock_irq(&dev->power.lock);
508
509 schedule();
510
511 spin_lock_irq(&dev->power.lock);
512 }
513 finish_wait(&dev->power.wait_queue, &wait);
514 goto repeat;
515 }
516
517 /*
518 * See if we can skip waking up the parent. This is safe only if
519 * power.no_callbacks is set, because otherwise we don't know whether
520 * the resume will actually succeed.
521 */
522 if (dev->power.no_callbacks && !parent && dev->parent) {
523 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
524 if (dev->parent->power.disable_depth > 0
525 || dev->parent->power.ignore_children
526 || dev->parent->power.runtime_status == RPM_ACTIVE) {
527 atomic_inc(&dev->parent->power.child_count);
528 spin_unlock(&dev->parent->power.lock);
529 goto no_callback; /* Assume success. */
530 }
531 spin_unlock(&dev->parent->power.lock);
532 }
533
534 /* Carry out an asynchronous or a synchronous resume. */
535 if (rpmflags & RPM_ASYNC) {
536 dev->power.request = RPM_REQ_RESUME;
537 if (!dev->power.request_pending) {
538 dev->power.request_pending = true;
539 queue_work(pm_wq, &dev->power.work);
540 }
541 retval = 0;
542 goto out;
543 }
544
545 if (!parent && dev->parent) {
546 /*
547 * Increment the parent's usage counter and resume it if
548 * necessary. Not needed if dev is irq-safe; then the
549 * parent is permanently resumed.
550 */
551 parent = dev->parent;
552 if (dev->power.irq_safe)
553 goto skip_parent;
554 spin_unlock(&dev->power.lock);
555
556 pm_runtime_get_noresume(parent);
557
558 spin_lock(&parent->power.lock);
559 /*
560 * We can resume if the parent's runtime PM is disabled or it
561 * is set to ignore children.
562 */
563 if (!parent->power.disable_depth
564 && !parent->power.ignore_children) {
565 rpm_resume(parent, 0);
566 if (parent->power.runtime_status != RPM_ACTIVE)
567 retval = -EBUSY;
568 }
569 spin_unlock(&parent->power.lock);
570
571 spin_lock(&dev->power.lock);
572 if (retval)
573 goto out;
574 goto repeat;
575 }
576 skip_parent:
577
578 if (dev->power.no_callbacks)
579 goto no_callback; /* Assume success. */
580
581 __update_runtime_status(dev, RPM_RESUMING);
582
583 if (dev->pm_domain)
584 callback = dev->pm_domain->ops.runtime_resume;
585 else if (dev->type && dev->type->pm)
586 callback = dev->type->pm->runtime_resume;
587 else if (dev->class && dev->class->pm)
588 callback = dev->class->pm->runtime_resume;
589 else if (dev->bus && dev->bus->pm)
590 callback = dev->bus->pm->runtime_resume;
591 else
592 callback = NULL;
593
594 retval = rpm_callback(callback, dev);
595 if (retval) {
596 __update_runtime_status(dev, RPM_SUSPENDED);
597 pm_runtime_cancel_pending(dev);
598 } else {
599 no_callback:
600 __update_runtime_status(dev, RPM_ACTIVE);
601 if (parent)
602 atomic_inc(&parent->power.child_count);
603 }
604 wake_up_all(&dev->power.wait_queue);
605
606 if (!retval)
607 rpm_idle(dev, RPM_ASYNC);
608
609 out:
610 if (parent && !dev->power.irq_safe) {
611 spin_unlock_irq(&dev->power.lock);
612
613 pm_runtime_put(parent);
614
615 spin_lock_irq(&dev->power.lock);
616 }
617
618 dev_dbg(dev, "%s returns %d\n", __func__, retval);
619
620 return retval;
621}
622
623/**
624 * pm_runtime_work - Universal runtime PM work function.
625 * @work: Work structure used for scheduling the execution of this function.
626 *
627 * Use @work to get the device object the work is to be done for, determine what
628 * is to be done and execute the appropriate runtime PM function.
629 */
630static void pm_runtime_work(struct work_struct *work)
631{
632 struct device *dev = container_of(work, struct device, power.work);
633 enum rpm_request req;
634
635 spin_lock_irq(&dev->power.lock);
636
637 if (!dev->power.request_pending)
638 goto out;
639
640 req = dev->power.request;
641 dev->power.request = RPM_REQ_NONE;
642 dev->power.request_pending = false;
643
644 switch (req) {
645 case RPM_REQ_NONE:
646 break;
647 case RPM_REQ_IDLE:
648 rpm_idle(dev, RPM_NOWAIT);
649 break;
650 case RPM_REQ_SUSPEND:
651 rpm_suspend(dev, RPM_NOWAIT);
652 break;
653 case RPM_REQ_AUTOSUSPEND:
654 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
655 break;
656 case RPM_REQ_RESUME:
657 rpm_resume(dev, RPM_NOWAIT);
658 break;
659 }
660
661 out:
662 spin_unlock_irq(&dev->power.lock);
663}
664
665/**
666 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
667 * @data: Device pointer passed by pm_schedule_suspend().
668 *
669 * Check if the time is right and queue a suspend request.
670 */
671static void pm_suspend_timer_fn(unsigned long data)
672{
673 struct device *dev = (struct device *)data;
674 unsigned long flags;
675 unsigned long expires;
676
677 spin_lock_irqsave(&dev->power.lock, flags);
678
679 expires = dev->power.timer_expires;
680 /* If 'expire' is after 'jiffies' we've been called too early. */
681 if (expires > 0 && !time_after(expires, jiffies)) {
682 dev->power.timer_expires = 0;
683 rpm_suspend(dev, dev->power.timer_autosuspends ?
684 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
685 }
686
687 spin_unlock_irqrestore(&dev->power.lock, flags);
688}
689
690/**
691 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
692 * @dev: Device to suspend.
693 * @delay: Time to wait before submitting a suspend request, in milliseconds.
694 */
695int pm_schedule_suspend(struct device *dev, unsigned int delay)
696{
697 unsigned long flags;
698 int retval;
699
700 spin_lock_irqsave(&dev->power.lock, flags);
701
702 if (!delay) {
703 retval = rpm_suspend(dev, RPM_ASYNC);
704 goto out;
705 }
706
707 retval = rpm_check_suspend_allowed(dev);
708 if (retval)
709 goto out;
710
711 /* Other scheduled or pending requests need to be canceled. */
712 pm_runtime_cancel_pending(dev);
713
714 dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
715 dev->power.timer_expires += !dev->power.timer_expires;
716 dev->power.timer_autosuspends = 0;
717 mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
718
719 out:
720 spin_unlock_irqrestore(&dev->power.lock, flags);
721
722 return retval;
723}
724EXPORT_SYMBOL_GPL(pm_schedule_suspend);
725
726/**
727 * __pm_runtime_idle - Entry point for runtime idle operations.
728 * @dev: Device to send idle notification for.
729 * @rpmflags: Flag bits.
730 *
731 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
732 * return immediately if it is larger than zero. Then carry out an idle
733 * notification, either synchronous or asynchronous.
734 *
735 * This routine may be called in atomic context if the RPM_ASYNC flag is set.
736 */
737int __pm_runtime_idle(struct device *dev, int rpmflags)
738{
739 unsigned long flags;
740 int retval;
741
742 if (rpmflags & RPM_GET_PUT) {
743 if (!atomic_dec_and_test(&dev->power.usage_count))
744 return 0;
745 }
746
747 spin_lock_irqsave(&dev->power.lock, flags);
748 retval = rpm_idle(dev, rpmflags);
749 spin_unlock_irqrestore(&dev->power.lock, flags);
750
751 return retval;
752}
753EXPORT_SYMBOL_GPL(__pm_runtime_idle);
754
755/**
756 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
757 * @dev: Device to suspend.
758 * @rpmflags: Flag bits.
759 *
760 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
761 * return immediately if it is larger than zero. Then carry out a suspend,
762 * either synchronous or asynchronous.
763 *
764 * This routine may be called in atomic context if the RPM_ASYNC flag is set.
765 */
766int __pm_runtime_suspend(struct device *dev, int rpmflags)
767{
768 unsigned long flags;
769 int retval;
770
771 if (rpmflags & RPM_GET_PUT) {
772 if (!atomic_dec_and_test(&dev->power.usage_count))
773 return 0;
774 }
775
776 spin_lock_irqsave(&dev->power.lock, flags);
777 retval = rpm_suspend(dev, rpmflags);
778 spin_unlock_irqrestore(&dev->power.lock, flags);
779
780 return retval;
781}
782EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
783
784/**
785 * __pm_runtime_resume - Entry point for runtime resume operations.
786 * @dev: Device to resume.
787 * @rpmflags: Flag bits.
788 *
789 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
790 * carry out a resume, either synchronous or asynchronous.
791 *
792 * This routine may be called in atomic context if the RPM_ASYNC flag is set.
793 */
794int __pm_runtime_resume(struct device *dev, int rpmflags)
795{
796 unsigned long flags;
797 int retval;
798
799 if (rpmflags & RPM_GET_PUT)
800 atomic_inc(&dev->power.usage_count);
801
802 spin_lock_irqsave(&dev->power.lock, flags);
803 retval = rpm_resume(dev, rpmflags);
804 spin_unlock_irqrestore(&dev->power.lock, flags);
805
806 return retval;
807}
808EXPORT_SYMBOL_GPL(__pm_runtime_resume);
809
810/**
811 * __pm_runtime_set_status - Set runtime PM status of a device.
812 * @dev: Device to handle.
813 * @status: New runtime PM status of the device.
814 *
815 * If runtime PM of the device is disabled or its power.runtime_error field is
816 * different from zero, the status may be changed either to RPM_ACTIVE, or to
817 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
818 * However, if the device has a parent and the parent is not active, and the
819 * parent's power.ignore_children flag is unset, the device's status cannot be
820 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
821 *
822 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
823 * and the device parent's counter of unsuspended children is modified to
824 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
825 * notification request for the parent is submitted.
826 */
827int __pm_runtime_set_status(struct device *dev, unsigned int status)
828{
829 struct device *parent = dev->parent;
830 unsigned long flags;
831 bool notify_parent = false;
832 int error = 0;
833
834 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
835 return -EINVAL;
836
837 spin_lock_irqsave(&dev->power.lock, flags);
838
839 if (!dev->power.runtime_error && !dev->power.disable_depth) {
840 error = -EAGAIN;
841 goto out;
842 }
843
844 if (dev->power.runtime_status == status)
845 goto out_set;
846
847 if (status == RPM_SUSPENDED) {
848 /* It always is possible to set the status to 'suspended'. */
849 if (parent) {
850 atomic_add_unless(&parent->power.child_count, -1, 0);
851 notify_parent = !parent->power.ignore_children;
852 }
853 goto out_set;
854 }
855
856 if (parent) {
857 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
858
859 /*
860 * It is invalid to put an active child under a parent that is
861 * not active, has runtime PM enabled and the
862 * 'power.ignore_children' flag unset.
863 */
864 if (!parent->power.disable_depth
865 && !parent->power.ignore_children
866 && parent->power.runtime_status != RPM_ACTIVE)
867 error = -EBUSY;
868 else if (dev->power.runtime_status == RPM_SUSPENDED)
869 atomic_inc(&parent->power.child_count);
870
871 spin_unlock(&parent->power.lock);
872
873 if (error)
874 goto out;
875 }
876
877 out_set:
878 __update_runtime_status(dev, status);
879 dev->power.runtime_error = 0;
880 out:
881 spin_unlock_irqrestore(&dev->power.lock, flags);
882
883 if (notify_parent)
884 pm_request_idle(parent);
885
886 return error;
887}
888EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
889
890/**
891 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
892 * @dev: Device to handle.
893 *
894 * Flush all pending requests for the device from pm_wq and wait for all
895 * runtime PM operations involving the device in progress to complete.
896 *
897 * Should be called under dev->power.lock with interrupts disabled.
898 */
899static void __pm_runtime_barrier(struct device *dev)
900{
901 pm_runtime_deactivate_timer(dev);
902
903 if (dev->power.request_pending) {
904 dev->power.request = RPM_REQ_NONE;
905 spin_unlock_irq(&dev->power.lock);
906
907 cancel_work_sync(&dev->power.work);
908
909 spin_lock_irq(&dev->power.lock);
910 dev->power.request_pending = false;
911 }
912
913 if (dev->power.runtime_status == RPM_SUSPENDING
914 || dev->power.runtime_status == RPM_RESUMING
915 || dev->power.idle_notification) {
916 DEFINE_WAIT(wait);
917
918 /* Suspend, wake-up or idle notification in progress. */
919 for (;;) {
920 prepare_to_wait(&dev->power.wait_queue, &wait,
921 TASK_UNINTERRUPTIBLE);
922 if (dev->power.runtime_status != RPM_SUSPENDING
923 && dev->power.runtime_status != RPM_RESUMING
924 && !dev->power.idle_notification)
925 break;
926 spin_unlock_irq(&dev->power.lock);
927
928 schedule();
929
930 spin_lock_irq(&dev->power.lock);
931 }
932 finish_wait(&dev->power.wait_queue, &wait);
933 }
934}
935
936/**
937 * pm_runtime_barrier - Flush pending requests and wait for completions.
938 * @dev: Device to handle.
939 *
940 * Prevent the device from being suspended by incrementing its usage counter and
941 * if there's a pending resume request for the device, wake the device up.
942 * Next, make sure that all pending requests for the device have been flushed
943 * from pm_wq and wait for all runtime PM operations involving the device in
944 * progress to complete.
945 *
946 * Return value:
947 * 1, if there was a resume request pending and the device had to be woken up,
948 * 0, otherwise
949 */
950int pm_runtime_barrier(struct device *dev)
951{
952 int retval = 0;
953
954 pm_runtime_get_noresume(dev);
955 spin_lock_irq(&dev->power.lock);
956
957 if (dev->power.request_pending
958 && dev->power.request == RPM_REQ_RESUME) {
959 rpm_resume(dev, 0);
960 retval = 1;
961 }
962
963 __pm_runtime_barrier(dev);
964
965 spin_unlock_irq(&dev->power.lock);
966 pm_runtime_put_noidle(dev);
967
968 return retval;
969}
970EXPORT_SYMBOL_GPL(pm_runtime_barrier);
971
972/**
973 * __pm_runtime_disable - Disable runtime PM of a device.
974 * @dev: Device to handle.
975 * @check_resume: If set, check if there's a resume request for the device.
976 *
977 * Increment power.disable_depth for the device and if was zero previously,
978 * cancel all pending runtime PM requests for the device and wait for all
979 * operations in progress to complete. The device can be either active or
980 * suspended after its runtime PM has been disabled.
981 *
982 * If @check_resume is set and there's a resume request pending when
983 * __pm_runtime_disable() is called and power.disable_depth is zero, the
984 * function will wake up the device before disabling its runtime PM.
985 */
986void __pm_runtime_disable(struct device *dev, bool check_resume)
987{
988 spin_lock_irq(&dev->power.lock);
989
990 if (dev->power.disable_depth > 0) {
991 dev->power.disable_depth++;
992 goto out;
993 }
994
995 /*
996 * Wake up the device if there's a resume request pending, because that
997 * means there probably is some I/O to process and disabling runtime PM
998 * shouldn't prevent the device from processing the I/O.
999 */
1000 if (check_resume && dev->power.request_pending
1001 && dev->power.request == RPM_REQ_RESUME) {
1002 /*
1003 * Prevent suspends and idle notifications from being carried
1004 * out after we have woken up the device.
1005 */
1006 pm_runtime_get_noresume(dev);
1007
1008 rpm_resume(dev, 0);
1009
1010 pm_runtime_put_noidle(dev);
1011 }
1012
1013 if (!dev->power.disable_depth++)
1014 __pm_runtime_barrier(dev);
1015
1016 out:
1017 spin_unlock_irq(&dev->power.lock);
1018}
1019EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1020
1021/**
1022 * pm_runtime_enable - Enable runtime PM of a device.
1023 * @dev: Device to handle.
1024 */
1025void pm_runtime_enable(struct device *dev)
1026{
1027 unsigned long flags;
1028
1029 spin_lock_irqsave(&dev->power.lock, flags);
1030
1031 if (dev->power.disable_depth > 0)
1032 dev->power.disable_depth--;
1033 else
1034 dev_warn(dev, "Unbalanced %s!\n", __func__);
1035
1036 spin_unlock_irqrestore(&dev->power.lock, flags);
1037}
1038EXPORT_SYMBOL_GPL(pm_runtime_enable);
1039
1040/**
1041 * pm_runtime_forbid - Block runtime PM of a device.
1042 * @dev: Device to handle.
1043 *
1044 * Increase the device's usage count and clear its power.runtime_auto flag,
1045 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1046 * for it.
1047 */
1048void pm_runtime_forbid(struct device *dev)
1049{
1050 spin_lock_irq(&dev->power.lock);
1051 if (!dev->power.runtime_auto)
1052 goto out;
1053
1054 dev->power.runtime_auto = false;
1055 atomic_inc(&dev->power.usage_count);
1056 rpm_resume(dev, 0);
1057
1058 out:
1059 spin_unlock_irq(&dev->power.lock);
1060}
1061EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1062
1063/**
1064 * pm_runtime_allow - Unblock runtime PM of a device.
1065 * @dev: Device to handle.
1066 *
1067 * Decrease the device's usage count and set its power.runtime_auto flag.
1068 */
1069void pm_runtime_allow(struct device *dev)
1070{
1071 spin_lock_irq(&dev->power.lock);
1072 if (dev->power.runtime_auto)
1073 goto out;
1074
1075 dev->power.runtime_auto = true;
1076 if (atomic_dec_and_test(&dev->power.usage_count))
1077 rpm_idle(dev, RPM_AUTO);
1078
1079 out:
1080 spin_unlock_irq(&dev->power.lock);
1081}
1082EXPORT_SYMBOL_GPL(pm_runtime_allow);
1083
1084/**
1085 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1086 * @dev: Device to handle.
1087 *
1088 * Set the power.no_callbacks flag, which tells the PM core that this
1089 * device is power-managed through its parent and has no runtime PM
1090 * callbacks of its own. The runtime sysfs attributes will be removed.
1091 */
1092void pm_runtime_no_callbacks(struct device *dev)
1093{
1094 spin_lock_irq(&dev->power.lock);
1095 dev->power.no_callbacks = 1;
1096 spin_unlock_irq(&dev->power.lock);
1097 if (device_is_registered(dev))
1098 rpm_sysfs_remove(dev);
1099}
1100EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1101
1102/**
1103 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1104 * @dev: Device to handle
1105 *
1106 * Set the power.irq_safe flag, which tells the PM core that the
1107 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1108 * always be invoked with the spinlock held and interrupts disabled. It also
1109 * causes the parent's usage counter to be permanently incremented, preventing
1110 * the parent from runtime suspending -- otherwise an irq-safe child might have
1111 * to wait for a non-irq-safe parent.
1112 */
1113void pm_runtime_irq_safe(struct device *dev)
1114{
1115 if (dev->parent)
1116 pm_runtime_get_sync(dev->parent);
1117 spin_lock_irq(&dev->power.lock);
1118 dev->power.irq_safe = 1;
1119 spin_unlock_irq(&dev->power.lock);
1120}
1121EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1122
1123/**
1124 * update_autosuspend - Handle a change to a device's autosuspend settings.
1125 * @dev: Device to handle.
1126 * @old_delay: The former autosuspend_delay value.
1127 * @old_use: The former use_autosuspend value.
1128 *
1129 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1130 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1131 *
1132 * This function must be called under dev->power.lock with interrupts disabled.
1133 */
1134static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1135{
1136 int delay = dev->power.autosuspend_delay;
1137
1138 /* Should runtime suspend be prevented now? */
1139 if (dev->power.use_autosuspend && delay < 0) {
1140
1141 /* If it used to be allowed then prevent it. */
1142 if (!old_use || old_delay >= 0) {
1143 atomic_inc(&dev->power.usage_count);
1144 rpm_resume(dev, 0);
1145 }
1146 }
1147
1148 /* Runtime suspend should be allowed now. */
1149 else {
1150
1151 /* If it used to be prevented then allow it. */
1152 if (old_use && old_delay < 0)
1153 atomic_dec(&dev->power.usage_count);
1154
1155 /* Maybe we can autosuspend now. */
1156 rpm_idle(dev, RPM_AUTO);
1157 }
1158}
1159
1160/**
1161 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1162 * @dev: Device to handle.
1163 * @delay: Value of the new delay in milliseconds.
1164 *
1165 * Set the device's power.autosuspend_delay value. If it changes to negative
1166 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1167 * changes the other way, allow runtime suspends.
1168 */
1169void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1170{
1171 int old_delay, old_use;
1172
1173 spin_lock_irq(&dev->power.lock);
1174 old_delay = dev->power.autosuspend_delay;
1175 old_use = dev->power.use_autosuspend;
1176 dev->power.autosuspend_delay = delay;
1177 update_autosuspend(dev, old_delay, old_use);
1178 spin_unlock_irq(&dev->power.lock);
1179}
1180EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1181
1182/**
1183 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1184 * @dev: Device to handle.
1185 * @use: New value for use_autosuspend.
1186 *
1187 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1188 * suspends as needed.
1189 */
1190void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1191{
1192 int old_delay, old_use;
1193
1194 spin_lock_irq(&dev->power.lock);
1195 old_delay = dev->power.autosuspend_delay;
1196 old_use = dev->power.use_autosuspend;
1197 dev->power.use_autosuspend = use;
1198 update_autosuspend(dev, old_delay, old_use);
1199 spin_unlock_irq(&dev->power.lock);
1200}
1201EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1202
1203/**
1204 * pm_runtime_init - Initialize runtime PM fields in given device object.
1205 * @dev: Device object to initialize.
1206 */
1207void pm_runtime_init(struct device *dev)
1208{
1209 dev->power.runtime_status = RPM_SUSPENDED;
1210 dev->power.idle_notification = false;
1211
1212 dev->power.disable_depth = 1;
1213 atomic_set(&dev->power.usage_count, 0);
1214
1215 dev->power.runtime_error = 0;
1216
1217 atomic_set(&dev->power.child_count, 0);
1218 pm_suspend_ignore_children(dev, false);
1219 dev->power.runtime_auto = true;
1220
1221 dev->power.request_pending = false;
1222 dev->power.request = RPM_REQ_NONE;
1223 dev->power.deferred_resume = false;
1224 dev->power.accounting_timestamp = jiffies;
1225 INIT_WORK(&dev->power.work, pm_runtime_work);
1226
1227 dev->power.timer_expires = 0;
1228 setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1229 (unsigned long)dev);
1230
1231 init_waitqueue_head(&dev->power.wait_queue);
1232}
1233
1234/**
1235 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1236 * @dev: Device object being removed from device hierarchy.
1237 */
1238void pm_runtime_remove(struct device *dev)
1239{
1240 __pm_runtime_disable(dev, false);
1241
1242 /* Change the status back to 'suspended' to match the initial status. */
1243 if (dev->power.runtime_status == RPM_ACTIVE)
1244 pm_runtime_set_suspended(dev);
1245 if (dev->power.irq_safe && dev->parent)
1246 pm_runtime_put_sync(dev->parent);
1247}
1/*
2 * drivers/base/power/runtime.c - Helper functions for device runtime PM
3 *
4 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
6 *
7 * This file is released under the GPLv2.
8 */
9
10#include <linux/sched.h>
11#include <linux/export.h>
12#include <linux/pm_runtime.h>
13#include <trace/events/rpm.h>
14#include "power.h"
15
16static int rpm_resume(struct device *dev, int rpmflags);
17static int rpm_suspend(struct device *dev, int rpmflags);
18
19/**
20 * update_pm_runtime_accounting - Update the time accounting of power states
21 * @dev: Device to update the accounting for
22 *
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
28 * correctly.
29 */
30void update_pm_runtime_accounting(struct device *dev)
31{
32 unsigned long now = jiffies;
33 unsigned long delta;
34
35 delta = now - dev->power.accounting_timestamp;
36
37 dev->power.accounting_timestamp = now;
38
39 if (dev->power.disable_depth > 0)
40 return;
41
42 if (dev->power.runtime_status == RPM_SUSPENDED)
43 dev->power.suspended_jiffies += delta;
44 else
45 dev->power.active_jiffies += delta;
46}
47
48static void __update_runtime_status(struct device *dev, enum rpm_status status)
49{
50 update_pm_runtime_accounting(dev);
51 dev->power.runtime_status = status;
52}
53
54/**
55 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
56 * @dev: Device to handle.
57 */
58static void pm_runtime_deactivate_timer(struct device *dev)
59{
60 if (dev->power.timer_expires > 0) {
61 del_timer(&dev->power.suspend_timer);
62 dev->power.timer_expires = 0;
63 }
64}
65
66/**
67 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
68 * @dev: Device to handle.
69 */
70static void pm_runtime_cancel_pending(struct device *dev)
71{
72 pm_runtime_deactivate_timer(dev);
73 /*
74 * In case there's a request pending, make sure its work function will
75 * return without doing anything.
76 */
77 dev->power.request = RPM_REQ_NONE;
78}
79
80/*
81 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
82 * @dev: Device to handle.
83 *
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).
88 *
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.
91 */
92unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
93{
94 int autosuspend_delay;
95 long elapsed;
96 unsigned long last_busy;
97 unsigned long expires = 0;
98
99 if (!dev->power.use_autosuspend)
100 goto out;
101
102 autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
103 if (autosuspend_delay < 0)
104 goto out;
105
106 last_busy = ACCESS_ONCE(dev->power.last_busy);
107 elapsed = jiffies - last_busy;
108 if (elapsed < 0)
109 goto out; /* jiffies has wrapped around. */
110
111 /*
112 * If the autosuspend_delay is >= 1 second, align the timer by rounding
113 * up to the nearest second.
114 */
115 expires = last_busy + msecs_to_jiffies(autosuspend_delay);
116 if (autosuspend_delay >= 1000)
117 expires = round_jiffies(expires);
118 expires += !expires;
119 if (elapsed >= expires - last_busy)
120 expires = 0; /* Already expired. */
121
122 out:
123 return expires;
124}
125EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
126
127/**
128 * rpm_check_suspend_allowed - Test whether a device may be suspended.
129 * @dev: Device to test.
130 */
131static int rpm_check_suspend_allowed(struct device *dev)
132{
133 int retval = 0;
134
135 if (dev->power.runtime_error)
136 retval = -EINVAL;
137 else if (dev->power.disable_depth > 0)
138 retval = -EACCES;
139 else if (atomic_read(&dev->power.usage_count) > 0)
140 retval = -EAGAIN;
141 else if (!pm_children_suspended(dev))
142 retval = -EBUSY;
143
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))
149 retval = -EAGAIN;
150 else if (__dev_pm_qos_read_value(dev) < 0)
151 retval = -EPERM;
152 else if (dev->power.runtime_status == RPM_SUSPENDED)
153 retval = 1;
154
155 return retval;
156}
157
158/**
159 * __rpm_callback - Run a given runtime PM callback for a given device.
160 * @cb: Runtime PM callback to run.
161 * @dev: Device to run the callback for.
162 */
163static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
164 __releases(&dev->power.lock) __acquires(&dev->power.lock)
165{
166 int retval;
167
168 if (dev->power.irq_safe)
169 spin_unlock(&dev->power.lock);
170 else
171 spin_unlock_irq(&dev->power.lock);
172
173 retval = cb(dev);
174
175 if (dev->power.irq_safe)
176 spin_lock(&dev->power.lock);
177 else
178 spin_lock_irq(&dev->power.lock);
179
180 return retval;
181}
182
183/**
184 * rpm_idle - Notify device bus type if the device can be suspended.
185 * @dev: Device to notify the bus type about.
186 * @rpmflags: Flag bits.
187 *
188 * Check if the device's runtime PM status allows it to be suspended. If
189 * another idle notification has been started earlier, return immediately. If
190 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
191 * run the ->runtime_idle() callback directly.
192 *
193 * This function must be called under dev->power.lock with interrupts disabled.
194 */
195static int rpm_idle(struct device *dev, int rpmflags)
196{
197 int (*callback)(struct device *);
198 int retval;
199
200 trace_rpm_idle(dev, rpmflags);
201 retval = rpm_check_suspend_allowed(dev);
202 if (retval < 0)
203 ; /* Conditions are wrong. */
204
205 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
206 else if (dev->power.runtime_status != RPM_ACTIVE)
207 retval = -EAGAIN;
208
209 /*
210 * Any pending request other than an idle notification takes
211 * precedence over us, except that the timer may be running.
212 */
213 else if (dev->power.request_pending &&
214 dev->power.request > RPM_REQ_IDLE)
215 retval = -EAGAIN;
216
217 /* Act as though RPM_NOWAIT is always set. */
218 else if (dev->power.idle_notification)
219 retval = -EINPROGRESS;
220 if (retval)
221 goto out;
222
223 /* Pending requests need to be canceled. */
224 dev->power.request = RPM_REQ_NONE;
225
226 if (dev->power.no_callbacks) {
227 /* Assume ->runtime_idle() callback would have suspended. */
228 retval = rpm_suspend(dev, rpmflags);
229 goto out;
230 }
231
232 /* Carry out an asynchronous or a synchronous idle notification. */
233 if (rpmflags & RPM_ASYNC) {
234 dev->power.request = RPM_REQ_IDLE;
235 if (!dev->power.request_pending) {
236 dev->power.request_pending = true;
237 queue_work(pm_wq, &dev->power.work);
238 }
239 goto out;
240 }
241
242 dev->power.idle_notification = true;
243
244 if (dev->pm_domain)
245 callback = dev->pm_domain->ops.runtime_idle;
246 else if (dev->type && dev->type->pm)
247 callback = dev->type->pm->runtime_idle;
248 else if (dev->class && dev->class->pm)
249 callback = dev->class->pm->runtime_idle;
250 else if (dev->bus && dev->bus->pm)
251 callback = dev->bus->pm->runtime_idle;
252 else
253 callback = NULL;
254
255 if (!callback && dev->driver && dev->driver->pm)
256 callback = dev->driver->pm->runtime_idle;
257
258 if (callback)
259 __rpm_callback(callback, dev);
260
261 dev->power.idle_notification = false;
262 wake_up_all(&dev->power.wait_queue);
263
264 out:
265 trace_rpm_return_int(dev, _THIS_IP_, retval);
266 return retval;
267}
268
269/**
270 * rpm_callback - Run a given runtime PM callback for a given device.
271 * @cb: Runtime PM callback to run.
272 * @dev: Device to run the callback for.
273 */
274static int rpm_callback(int (*cb)(struct device *), struct device *dev)
275{
276 int retval;
277
278 if (!cb)
279 return -ENOSYS;
280
281 retval = __rpm_callback(cb, dev);
282
283 dev->power.runtime_error = retval;
284 return retval != -EACCES ? retval : -EIO;
285}
286
287/**
288 * rpm_suspend - Carry out runtime suspend of given device.
289 * @dev: Device to suspend.
290 * @rpmflags: Flag bits.
291 *
292 * Check if the device's runtime PM status allows it to be suspended.
293 * Cancel a pending idle notification, autosuspend or suspend. If
294 * another suspend has been started earlier, either return immediately
295 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
296 * flags. If the RPM_ASYNC flag is set then queue a suspend request;
297 * otherwise run the ->runtime_suspend() callback directly. When
298 * ->runtime_suspend succeeded, if a deferred resume was requested while
299 * the callback was running then carry it out, otherwise send an idle
300 * notification for its parent (if the suspend succeeded and both
301 * ignore_children of parent->power and irq_safe of dev->power are not set).
302 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
303 * flag is set and the next autosuspend-delay expiration time is in the
304 * future, schedule another autosuspend attempt.
305 *
306 * This function must be called under dev->power.lock with interrupts disabled.
307 */
308static int rpm_suspend(struct device *dev, int rpmflags)
309 __releases(&dev->power.lock) __acquires(&dev->power.lock)
310{
311 int (*callback)(struct device *);
312 struct device *parent = NULL;
313 int retval;
314
315 trace_rpm_suspend(dev, rpmflags);
316
317 repeat:
318 retval = rpm_check_suspend_allowed(dev);
319
320 if (retval < 0)
321 ; /* Conditions are wrong. */
322
323 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
324 else if (dev->power.runtime_status == RPM_RESUMING &&
325 !(rpmflags & RPM_ASYNC))
326 retval = -EAGAIN;
327 if (retval)
328 goto out;
329
330 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
331 if ((rpmflags & RPM_AUTO)
332 && dev->power.runtime_status != RPM_SUSPENDING) {
333 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
334
335 if (expires != 0) {
336 /* Pending requests need to be canceled. */
337 dev->power.request = RPM_REQ_NONE;
338
339 /*
340 * Optimization: If the timer is already running and is
341 * set to expire at or before the autosuspend delay,
342 * avoid the overhead of resetting it. Just let it
343 * expire; pm_suspend_timer_fn() will take care of the
344 * rest.
345 */
346 if (!(dev->power.timer_expires && time_before_eq(
347 dev->power.timer_expires, expires))) {
348 dev->power.timer_expires = expires;
349 mod_timer(&dev->power.suspend_timer, expires);
350 }
351 dev->power.timer_autosuspends = 1;
352 goto out;
353 }
354 }
355
356 /* Other scheduled or pending requests need to be canceled. */
357 pm_runtime_cancel_pending(dev);
358
359 if (dev->power.runtime_status == RPM_SUSPENDING) {
360 DEFINE_WAIT(wait);
361
362 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
363 retval = -EINPROGRESS;
364 goto out;
365 }
366
367 if (dev->power.irq_safe) {
368 spin_unlock(&dev->power.lock);
369
370 cpu_relax();
371
372 spin_lock(&dev->power.lock);
373 goto repeat;
374 }
375
376 /* Wait for the other suspend running in parallel with us. */
377 for (;;) {
378 prepare_to_wait(&dev->power.wait_queue, &wait,
379 TASK_UNINTERRUPTIBLE);
380 if (dev->power.runtime_status != RPM_SUSPENDING)
381 break;
382
383 spin_unlock_irq(&dev->power.lock);
384
385 schedule();
386
387 spin_lock_irq(&dev->power.lock);
388 }
389 finish_wait(&dev->power.wait_queue, &wait);
390 goto repeat;
391 }
392
393 if (dev->power.no_callbacks)
394 goto no_callback; /* Assume success. */
395
396 /* Carry out an asynchronous or a synchronous suspend. */
397 if (rpmflags & RPM_ASYNC) {
398 dev->power.request = (rpmflags & RPM_AUTO) ?
399 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
400 if (!dev->power.request_pending) {
401 dev->power.request_pending = true;
402 queue_work(pm_wq, &dev->power.work);
403 }
404 goto out;
405 }
406
407 __update_runtime_status(dev, RPM_SUSPENDING);
408
409 if (dev->pm_domain)
410 callback = dev->pm_domain->ops.runtime_suspend;
411 else if (dev->type && dev->type->pm)
412 callback = dev->type->pm->runtime_suspend;
413 else if (dev->class && dev->class->pm)
414 callback = dev->class->pm->runtime_suspend;
415 else if (dev->bus && dev->bus->pm)
416 callback = dev->bus->pm->runtime_suspend;
417 else
418 callback = NULL;
419
420 if (!callback && dev->driver && dev->driver->pm)
421 callback = dev->driver->pm->runtime_suspend;
422
423 retval = rpm_callback(callback, dev);
424 if (retval)
425 goto fail;
426
427 no_callback:
428 __update_runtime_status(dev, RPM_SUSPENDED);
429 pm_runtime_deactivate_timer(dev);
430
431 if (dev->parent) {
432 parent = dev->parent;
433 atomic_add_unless(&parent->power.child_count, -1, 0);
434 }
435 wake_up_all(&dev->power.wait_queue);
436
437 if (dev->power.deferred_resume) {
438 dev->power.deferred_resume = false;
439 rpm_resume(dev, 0);
440 retval = -EAGAIN;
441 goto out;
442 }
443
444 /* Maybe the parent is now able to suspend. */
445 if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
446 spin_unlock(&dev->power.lock);
447
448 spin_lock(&parent->power.lock);
449 rpm_idle(parent, RPM_ASYNC);
450 spin_unlock(&parent->power.lock);
451
452 spin_lock(&dev->power.lock);
453 }
454
455 out:
456 trace_rpm_return_int(dev, _THIS_IP_, retval);
457
458 return retval;
459
460 fail:
461 __update_runtime_status(dev, RPM_ACTIVE);
462 dev->power.deferred_resume = false;
463 wake_up_all(&dev->power.wait_queue);
464
465 if (retval == -EAGAIN || retval == -EBUSY) {
466 dev->power.runtime_error = 0;
467
468 /*
469 * If the callback routine failed an autosuspend, and
470 * if the last_busy time has been updated so that there
471 * is a new autosuspend expiration time, automatically
472 * reschedule another autosuspend.
473 */
474 if ((rpmflags & RPM_AUTO) &&
475 pm_runtime_autosuspend_expiration(dev) != 0)
476 goto repeat;
477 } else {
478 pm_runtime_cancel_pending(dev);
479 }
480 goto out;
481}
482
483/**
484 * rpm_resume - Carry out runtime resume of given device.
485 * @dev: Device to resume.
486 * @rpmflags: Flag bits.
487 *
488 * Check if the device's runtime PM status allows it to be resumed. Cancel
489 * any scheduled or pending requests. If another resume has been started
490 * earlier, either return immediately or wait for it to finish, depending on the
491 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
492 * parallel with this function, either tell the other process to resume after
493 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
494 * flag is set then queue a resume request; otherwise run the
495 * ->runtime_resume() callback directly. Queue an idle notification for the
496 * device if the resume succeeded.
497 *
498 * This function must be called under dev->power.lock with interrupts disabled.
499 */
500static int rpm_resume(struct device *dev, int rpmflags)
501 __releases(&dev->power.lock) __acquires(&dev->power.lock)
502{
503 int (*callback)(struct device *);
504 struct device *parent = NULL;
505 int retval = 0;
506
507 trace_rpm_resume(dev, rpmflags);
508
509 repeat:
510 if (dev->power.runtime_error)
511 retval = -EINVAL;
512 else if (dev->power.disable_depth > 0)
513 retval = -EACCES;
514 if (retval)
515 goto out;
516
517 /*
518 * Other scheduled or pending requests need to be canceled. Small
519 * optimization: If an autosuspend timer is running, leave it running
520 * rather than cancelling it now only to restart it again in the near
521 * future.
522 */
523 dev->power.request = RPM_REQ_NONE;
524 if (!dev->power.timer_autosuspends)
525 pm_runtime_deactivate_timer(dev);
526
527 if (dev->power.runtime_status == RPM_ACTIVE) {
528 retval = 1;
529 goto out;
530 }
531
532 if (dev->power.runtime_status == RPM_RESUMING
533 || dev->power.runtime_status == RPM_SUSPENDING) {
534 DEFINE_WAIT(wait);
535
536 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
537 if (dev->power.runtime_status == RPM_SUSPENDING)
538 dev->power.deferred_resume = true;
539 else
540 retval = -EINPROGRESS;
541 goto out;
542 }
543
544 if (dev->power.irq_safe) {
545 spin_unlock(&dev->power.lock);
546
547 cpu_relax();
548
549 spin_lock(&dev->power.lock);
550 goto repeat;
551 }
552
553 /* Wait for the operation carried out in parallel with us. */
554 for (;;) {
555 prepare_to_wait(&dev->power.wait_queue, &wait,
556 TASK_UNINTERRUPTIBLE);
557 if (dev->power.runtime_status != RPM_RESUMING
558 && dev->power.runtime_status != RPM_SUSPENDING)
559 break;
560
561 spin_unlock_irq(&dev->power.lock);
562
563 schedule();
564
565 spin_lock_irq(&dev->power.lock);
566 }
567 finish_wait(&dev->power.wait_queue, &wait);
568 goto repeat;
569 }
570
571 /*
572 * See if we can skip waking up the parent. This is safe only if
573 * power.no_callbacks is set, because otherwise we don't know whether
574 * the resume will actually succeed.
575 */
576 if (dev->power.no_callbacks && !parent && dev->parent) {
577 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
578 if (dev->parent->power.disable_depth > 0
579 || dev->parent->power.ignore_children
580 || dev->parent->power.runtime_status == RPM_ACTIVE) {
581 atomic_inc(&dev->parent->power.child_count);
582 spin_unlock(&dev->parent->power.lock);
583 retval = 1;
584 goto no_callback; /* Assume success. */
585 }
586 spin_unlock(&dev->parent->power.lock);
587 }
588
589 /* Carry out an asynchronous or a synchronous resume. */
590 if (rpmflags & RPM_ASYNC) {
591 dev->power.request = RPM_REQ_RESUME;
592 if (!dev->power.request_pending) {
593 dev->power.request_pending = true;
594 queue_work(pm_wq, &dev->power.work);
595 }
596 retval = 0;
597 goto out;
598 }
599
600 if (!parent && dev->parent) {
601 /*
602 * Increment the parent's usage counter and resume it if
603 * necessary. Not needed if dev is irq-safe; then the
604 * parent is permanently resumed.
605 */
606 parent = dev->parent;
607 if (dev->power.irq_safe)
608 goto skip_parent;
609 spin_unlock(&dev->power.lock);
610
611 pm_runtime_get_noresume(parent);
612
613 spin_lock(&parent->power.lock);
614 /*
615 * We can resume if the parent's runtime PM is disabled or it
616 * is set to ignore children.
617 */
618 if (!parent->power.disable_depth
619 && !parent->power.ignore_children) {
620 rpm_resume(parent, 0);
621 if (parent->power.runtime_status != RPM_ACTIVE)
622 retval = -EBUSY;
623 }
624 spin_unlock(&parent->power.lock);
625
626 spin_lock(&dev->power.lock);
627 if (retval)
628 goto out;
629 goto repeat;
630 }
631 skip_parent:
632
633 if (dev->power.no_callbacks)
634 goto no_callback; /* Assume success. */
635
636 __update_runtime_status(dev, RPM_RESUMING);
637
638 if (dev->pm_domain)
639 callback = dev->pm_domain->ops.runtime_resume;
640 else if (dev->type && dev->type->pm)
641 callback = dev->type->pm->runtime_resume;
642 else if (dev->class && dev->class->pm)
643 callback = dev->class->pm->runtime_resume;
644 else if (dev->bus && dev->bus->pm)
645 callback = dev->bus->pm->runtime_resume;
646 else
647 callback = NULL;
648
649 if (!callback && dev->driver && dev->driver->pm)
650 callback = dev->driver->pm->runtime_resume;
651
652 retval = rpm_callback(callback, dev);
653 if (retval) {
654 __update_runtime_status(dev, RPM_SUSPENDED);
655 pm_runtime_cancel_pending(dev);
656 } else {
657 no_callback:
658 __update_runtime_status(dev, RPM_ACTIVE);
659 if (parent)
660 atomic_inc(&parent->power.child_count);
661 }
662 wake_up_all(&dev->power.wait_queue);
663
664 if (retval >= 0)
665 rpm_idle(dev, RPM_ASYNC);
666
667 out:
668 if (parent && !dev->power.irq_safe) {
669 spin_unlock_irq(&dev->power.lock);
670
671 pm_runtime_put(parent);
672
673 spin_lock_irq(&dev->power.lock);
674 }
675
676 trace_rpm_return_int(dev, _THIS_IP_, retval);
677
678 return retval;
679}
680
681/**
682 * pm_runtime_work - Universal runtime PM work function.
683 * @work: Work structure used for scheduling the execution of this function.
684 *
685 * Use @work to get the device object the work is to be done for, determine what
686 * is to be done and execute the appropriate runtime PM function.
687 */
688static void pm_runtime_work(struct work_struct *work)
689{
690 struct device *dev = container_of(work, struct device, power.work);
691 enum rpm_request req;
692
693 spin_lock_irq(&dev->power.lock);
694
695 if (!dev->power.request_pending)
696 goto out;
697
698 req = dev->power.request;
699 dev->power.request = RPM_REQ_NONE;
700 dev->power.request_pending = false;
701
702 switch (req) {
703 case RPM_REQ_NONE:
704 break;
705 case RPM_REQ_IDLE:
706 rpm_idle(dev, RPM_NOWAIT);
707 break;
708 case RPM_REQ_SUSPEND:
709 rpm_suspend(dev, RPM_NOWAIT);
710 break;
711 case RPM_REQ_AUTOSUSPEND:
712 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
713 break;
714 case RPM_REQ_RESUME:
715 rpm_resume(dev, RPM_NOWAIT);
716 break;
717 }
718
719 out:
720 spin_unlock_irq(&dev->power.lock);
721}
722
723/**
724 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
725 * @data: Device pointer passed by pm_schedule_suspend().
726 *
727 * Check if the time is right and queue a suspend request.
728 */
729static void pm_suspend_timer_fn(unsigned long data)
730{
731 struct device *dev = (struct device *)data;
732 unsigned long flags;
733 unsigned long expires;
734
735 spin_lock_irqsave(&dev->power.lock, flags);
736
737 expires = dev->power.timer_expires;
738 /* If 'expire' is after 'jiffies' we've been called too early. */
739 if (expires > 0 && !time_after(expires, jiffies)) {
740 dev->power.timer_expires = 0;
741 rpm_suspend(dev, dev->power.timer_autosuspends ?
742 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
743 }
744
745 spin_unlock_irqrestore(&dev->power.lock, flags);
746}
747
748/**
749 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
750 * @dev: Device to suspend.
751 * @delay: Time to wait before submitting a suspend request, in milliseconds.
752 */
753int pm_schedule_suspend(struct device *dev, unsigned int delay)
754{
755 unsigned long flags;
756 int retval;
757
758 spin_lock_irqsave(&dev->power.lock, flags);
759
760 if (!delay) {
761 retval = rpm_suspend(dev, RPM_ASYNC);
762 goto out;
763 }
764
765 retval = rpm_check_suspend_allowed(dev);
766 if (retval)
767 goto out;
768
769 /* Other scheduled or pending requests need to be canceled. */
770 pm_runtime_cancel_pending(dev);
771
772 dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
773 dev->power.timer_expires += !dev->power.timer_expires;
774 dev->power.timer_autosuspends = 0;
775 mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
776
777 out:
778 spin_unlock_irqrestore(&dev->power.lock, flags);
779
780 return retval;
781}
782EXPORT_SYMBOL_GPL(pm_schedule_suspend);
783
784/**
785 * __pm_runtime_idle - Entry point for runtime idle operations.
786 * @dev: Device to send idle notification for.
787 * @rpmflags: Flag bits.
788 *
789 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
790 * return immediately if it is larger than zero. Then carry out an idle
791 * notification, either synchronous or asynchronous.
792 *
793 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
794 * or if pm_runtime_irq_safe() has been called.
795 */
796int __pm_runtime_idle(struct device *dev, int rpmflags)
797{
798 unsigned long flags;
799 int retval;
800
801 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
802
803 if (rpmflags & RPM_GET_PUT) {
804 if (!atomic_dec_and_test(&dev->power.usage_count))
805 return 0;
806 }
807
808 spin_lock_irqsave(&dev->power.lock, flags);
809 retval = rpm_idle(dev, rpmflags);
810 spin_unlock_irqrestore(&dev->power.lock, flags);
811
812 return retval;
813}
814EXPORT_SYMBOL_GPL(__pm_runtime_idle);
815
816/**
817 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
818 * @dev: Device to suspend.
819 * @rpmflags: Flag bits.
820 *
821 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
822 * return immediately if it is larger than zero. Then carry out a suspend,
823 * either synchronous or asynchronous.
824 *
825 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
826 * or if pm_runtime_irq_safe() has been called.
827 */
828int __pm_runtime_suspend(struct device *dev, int rpmflags)
829{
830 unsigned long flags;
831 int retval;
832
833 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
834
835 if (rpmflags & RPM_GET_PUT) {
836 if (!atomic_dec_and_test(&dev->power.usage_count))
837 return 0;
838 }
839
840 spin_lock_irqsave(&dev->power.lock, flags);
841 retval = rpm_suspend(dev, rpmflags);
842 spin_unlock_irqrestore(&dev->power.lock, flags);
843
844 return retval;
845}
846EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
847
848/**
849 * __pm_runtime_resume - Entry point for runtime resume operations.
850 * @dev: Device to resume.
851 * @rpmflags: Flag bits.
852 *
853 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
854 * carry out a resume, either synchronous or asynchronous.
855 *
856 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
857 * or if pm_runtime_irq_safe() has been called.
858 */
859int __pm_runtime_resume(struct device *dev, int rpmflags)
860{
861 unsigned long flags;
862 int retval;
863
864 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
865
866 if (rpmflags & RPM_GET_PUT)
867 atomic_inc(&dev->power.usage_count);
868
869 spin_lock_irqsave(&dev->power.lock, flags);
870 retval = rpm_resume(dev, rpmflags);
871 spin_unlock_irqrestore(&dev->power.lock, flags);
872
873 return retval;
874}
875EXPORT_SYMBOL_GPL(__pm_runtime_resume);
876
877/**
878 * __pm_runtime_set_status - Set runtime PM status of a device.
879 * @dev: Device to handle.
880 * @status: New runtime PM status of the device.
881 *
882 * If runtime PM of the device is disabled or its power.runtime_error field is
883 * different from zero, the status may be changed either to RPM_ACTIVE, or to
884 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
885 * However, if the device has a parent and the parent is not active, and the
886 * parent's power.ignore_children flag is unset, the device's status cannot be
887 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
888 *
889 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
890 * and the device parent's counter of unsuspended children is modified to
891 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
892 * notification request for the parent is submitted.
893 */
894int __pm_runtime_set_status(struct device *dev, unsigned int status)
895{
896 struct device *parent = dev->parent;
897 unsigned long flags;
898 bool notify_parent = false;
899 int error = 0;
900
901 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
902 return -EINVAL;
903
904 spin_lock_irqsave(&dev->power.lock, flags);
905
906 if (!dev->power.runtime_error && !dev->power.disable_depth) {
907 error = -EAGAIN;
908 goto out;
909 }
910
911 if (dev->power.runtime_status == status)
912 goto out_set;
913
914 if (status == RPM_SUSPENDED) {
915 /* It always is possible to set the status to 'suspended'. */
916 if (parent) {
917 atomic_add_unless(&parent->power.child_count, -1, 0);
918 notify_parent = !parent->power.ignore_children;
919 }
920 goto out_set;
921 }
922
923 if (parent) {
924 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
925
926 /*
927 * It is invalid to put an active child under a parent that is
928 * not active, has runtime PM enabled and the
929 * 'power.ignore_children' flag unset.
930 */
931 if (!parent->power.disable_depth
932 && !parent->power.ignore_children
933 && parent->power.runtime_status != RPM_ACTIVE)
934 error = -EBUSY;
935 else if (dev->power.runtime_status == RPM_SUSPENDED)
936 atomic_inc(&parent->power.child_count);
937
938 spin_unlock(&parent->power.lock);
939
940 if (error)
941 goto out;
942 }
943
944 out_set:
945 __update_runtime_status(dev, status);
946 dev->power.runtime_error = 0;
947 out:
948 spin_unlock_irqrestore(&dev->power.lock, flags);
949
950 if (notify_parent)
951 pm_request_idle(parent);
952
953 return error;
954}
955EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
956
957/**
958 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
959 * @dev: Device to handle.
960 *
961 * Flush all pending requests for the device from pm_wq and wait for all
962 * runtime PM operations involving the device in progress to complete.
963 *
964 * Should be called under dev->power.lock with interrupts disabled.
965 */
966static void __pm_runtime_barrier(struct device *dev)
967{
968 pm_runtime_deactivate_timer(dev);
969
970 if (dev->power.request_pending) {
971 dev->power.request = RPM_REQ_NONE;
972 spin_unlock_irq(&dev->power.lock);
973
974 cancel_work_sync(&dev->power.work);
975
976 spin_lock_irq(&dev->power.lock);
977 dev->power.request_pending = false;
978 }
979
980 if (dev->power.runtime_status == RPM_SUSPENDING
981 || dev->power.runtime_status == RPM_RESUMING
982 || dev->power.idle_notification) {
983 DEFINE_WAIT(wait);
984
985 /* Suspend, wake-up or idle notification in progress. */
986 for (;;) {
987 prepare_to_wait(&dev->power.wait_queue, &wait,
988 TASK_UNINTERRUPTIBLE);
989 if (dev->power.runtime_status != RPM_SUSPENDING
990 && dev->power.runtime_status != RPM_RESUMING
991 && !dev->power.idle_notification)
992 break;
993 spin_unlock_irq(&dev->power.lock);
994
995 schedule();
996
997 spin_lock_irq(&dev->power.lock);
998 }
999 finish_wait(&dev->power.wait_queue, &wait);
1000 }
1001}
1002
1003/**
1004 * pm_runtime_barrier - Flush pending requests and wait for completions.
1005 * @dev: Device to handle.
1006 *
1007 * Prevent the device from being suspended by incrementing its usage counter and
1008 * if there's a pending resume request for the device, wake the device up.
1009 * Next, make sure that all pending requests for the device have been flushed
1010 * from pm_wq and wait for all runtime PM operations involving the device in
1011 * progress to complete.
1012 *
1013 * Return value:
1014 * 1, if there was a resume request pending and the device had to be woken up,
1015 * 0, otherwise
1016 */
1017int pm_runtime_barrier(struct device *dev)
1018{
1019 int retval = 0;
1020
1021 pm_runtime_get_noresume(dev);
1022 spin_lock_irq(&dev->power.lock);
1023
1024 if (dev->power.request_pending
1025 && dev->power.request == RPM_REQ_RESUME) {
1026 rpm_resume(dev, 0);
1027 retval = 1;
1028 }
1029
1030 __pm_runtime_barrier(dev);
1031
1032 spin_unlock_irq(&dev->power.lock);
1033 pm_runtime_put_noidle(dev);
1034
1035 return retval;
1036}
1037EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1038
1039/**
1040 * __pm_runtime_disable - Disable runtime PM of a device.
1041 * @dev: Device to handle.
1042 * @check_resume: If set, check if there's a resume request for the device.
1043 *
1044 * Increment power.disable_depth for the device and if was zero previously,
1045 * cancel all pending runtime PM requests for the device and wait for all
1046 * operations in progress to complete. The device can be either active or
1047 * suspended after its runtime PM has been disabled.
1048 *
1049 * If @check_resume is set and there's a resume request pending when
1050 * __pm_runtime_disable() is called and power.disable_depth is zero, the
1051 * function will wake up the device before disabling its runtime PM.
1052 */
1053void __pm_runtime_disable(struct device *dev, bool check_resume)
1054{
1055 spin_lock_irq(&dev->power.lock);
1056
1057 if (dev->power.disable_depth > 0) {
1058 dev->power.disable_depth++;
1059 goto out;
1060 }
1061
1062 /*
1063 * Wake up the device if there's a resume request pending, because that
1064 * means there probably is some I/O to process and disabling runtime PM
1065 * shouldn't prevent the device from processing the I/O.
1066 */
1067 if (check_resume && dev->power.request_pending
1068 && dev->power.request == RPM_REQ_RESUME) {
1069 /*
1070 * Prevent suspends and idle notifications from being carried
1071 * out after we have woken up the device.
1072 */
1073 pm_runtime_get_noresume(dev);
1074
1075 rpm_resume(dev, 0);
1076
1077 pm_runtime_put_noidle(dev);
1078 }
1079
1080 if (!dev->power.disable_depth++)
1081 __pm_runtime_barrier(dev);
1082
1083 out:
1084 spin_unlock_irq(&dev->power.lock);
1085}
1086EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1087
1088/**
1089 * pm_runtime_enable - Enable runtime PM of a device.
1090 * @dev: Device to handle.
1091 */
1092void pm_runtime_enable(struct device *dev)
1093{
1094 unsigned long flags;
1095
1096 spin_lock_irqsave(&dev->power.lock, flags);
1097
1098 if (dev->power.disable_depth > 0)
1099 dev->power.disable_depth--;
1100 else
1101 dev_warn(dev, "Unbalanced %s!\n", __func__);
1102
1103 spin_unlock_irqrestore(&dev->power.lock, flags);
1104}
1105EXPORT_SYMBOL_GPL(pm_runtime_enable);
1106
1107/**
1108 * pm_runtime_forbid - Block runtime PM of a device.
1109 * @dev: Device to handle.
1110 *
1111 * Increase the device's usage count and clear its power.runtime_auto flag,
1112 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1113 * for it.
1114 */
1115void pm_runtime_forbid(struct device *dev)
1116{
1117 spin_lock_irq(&dev->power.lock);
1118 if (!dev->power.runtime_auto)
1119 goto out;
1120
1121 dev->power.runtime_auto = false;
1122 atomic_inc(&dev->power.usage_count);
1123 rpm_resume(dev, 0);
1124
1125 out:
1126 spin_unlock_irq(&dev->power.lock);
1127}
1128EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1129
1130/**
1131 * pm_runtime_allow - Unblock runtime PM of a device.
1132 * @dev: Device to handle.
1133 *
1134 * Decrease the device's usage count and set its power.runtime_auto flag.
1135 */
1136void pm_runtime_allow(struct device *dev)
1137{
1138 spin_lock_irq(&dev->power.lock);
1139 if (dev->power.runtime_auto)
1140 goto out;
1141
1142 dev->power.runtime_auto = true;
1143 if (atomic_dec_and_test(&dev->power.usage_count))
1144 rpm_idle(dev, RPM_AUTO);
1145
1146 out:
1147 spin_unlock_irq(&dev->power.lock);
1148}
1149EXPORT_SYMBOL_GPL(pm_runtime_allow);
1150
1151/**
1152 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1153 * @dev: Device to handle.
1154 *
1155 * Set the power.no_callbacks flag, which tells the PM core that this
1156 * device is power-managed through its parent and has no runtime PM
1157 * callbacks of its own. The runtime sysfs attributes will be removed.
1158 */
1159void pm_runtime_no_callbacks(struct device *dev)
1160{
1161 spin_lock_irq(&dev->power.lock);
1162 dev->power.no_callbacks = 1;
1163 spin_unlock_irq(&dev->power.lock);
1164 if (device_is_registered(dev))
1165 rpm_sysfs_remove(dev);
1166}
1167EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1168
1169/**
1170 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1171 * @dev: Device to handle
1172 *
1173 * Set the power.irq_safe flag, which tells the PM core that the
1174 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1175 * always be invoked with the spinlock held and interrupts disabled. It also
1176 * causes the parent's usage counter to be permanently incremented, preventing
1177 * the parent from runtime suspending -- otherwise an irq-safe child might have
1178 * to wait for a non-irq-safe parent.
1179 */
1180void pm_runtime_irq_safe(struct device *dev)
1181{
1182 if (dev->parent)
1183 pm_runtime_get_sync(dev->parent);
1184 spin_lock_irq(&dev->power.lock);
1185 dev->power.irq_safe = 1;
1186 spin_unlock_irq(&dev->power.lock);
1187}
1188EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1189
1190/**
1191 * update_autosuspend - Handle a change to a device's autosuspend settings.
1192 * @dev: Device to handle.
1193 * @old_delay: The former autosuspend_delay value.
1194 * @old_use: The former use_autosuspend value.
1195 *
1196 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1197 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1198 *
1199 * This function must be called under dev->power.lock with interrupts disabled.
1200 */
1201static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1202{
1203 int delay = dev->power.autosuspend_delay;
1204
1205 /* Should runtime suspend be prevented now? */
1206 if (dev->power.use_autosuspend && delay < 0) {
1207
1208 /* If it used to be allowed then prevent it. */
1209 if (!old_use || old_delay >= 0) {
1210 atomic_inc(&dev->power.usage_count);
1211 rpm_resume(dev, 0);
1212 }
1213 }
1214
1215 /* Runtime suspend should be allowed now. */
1216 else {
1217
1218 /* If it used to be prevented then allow it. */
1219 if (old_use && old_delay < 0)
1220 atomic_dec(&dev->power.usage_count);
1221
1222 /* Maybe we can autosuspend now. */
1223 rpm_idle(dev, RPM_AUTO);
1224 }
1225}
1226
1227/**
1228 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1229 * @dev: Device to handle.
1230 * @delay: Value of the new delay in milliseconds.
1231 *
1232 * Set the device's power.autosuspend_delay value. If it changes to negative
1233 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1234 * changes the other way, allow runtime suspends.
1235 */
1236void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1237{
1238 int old_delay, old_use;
1239
1240 spin_lock_irq(&dev->power.lock);
1241 old_delay = dev->power.autosuspend_delay;
1242 old_use = dev->power.use_autosuspend;
1243 dev->power.autosuspend_delay = delay;
1244 update_autosuspend(dev, old_delay, old_use);
1245 spin_unlock_irq(&dev->power.lock);
1246}
1247EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1248
1249/**
1250 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1251 * @dev: Device to handle.
1252 * @use: New value for use_autosuspend.
1253 *
1254 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1255 * suspends as needed.
1256 */
1257void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1258{
1259 int old_delay, old_use;
1260
1261 spin_lock_irq(&dev->power.lock);
1262 old_delay = dev->power.autosuspend_delay;
1263 old_use = dev->power.use_autosuspend;
1264 dev->power.use_autosuspend = use;
1265 update_autosuspend(dev, old_delay, old_use);
1266 spin_unlock_irq(&dev->power.lock);
1267}
1268EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1269
1270/**
1271 * pm_runtime_init - Initialize runtime PM fields in given device object.
1272 * @dev: Device object to initialize.
1273 */
1274void pm_runtime_init(struct device *dev)
1275{
1276 dev->power.runtime_status = RPM_SUSPENDED;
1277 dev->power.idle_notification = false;
1278
1279 dev->power.disable_depth = 1;
1280 atomic_set(&dev->power.usage_count, 0);
1281
1282 dev->power.runtime_error = 0;
1283
1284 atomic_set(&dev->power.child_count, 0);
1285 pm_suspend_ignore_children(dev, false);
1286 dev->power.runtime_auto = true;
1287
1288 dev->power.request_pending = false;
1289 dev->power.request = RPM_REQ_NONE;
1290 dev->power.deferred_resume = false;
1291 dev->power.accounting_timestamp = jiffies;
1292 INIT_WORK(&dev->power.work, pm_runtime_work);
1293
1294 dev->power.timer_expires = 0;
1295 setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1296 (unsigned long)dev);
1297
1298 init_waitqueue_head(&dev->power.wait_queue);
1299}
1300
1301/**
1302 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1303 * @dev: Device object being removed from device hierarchy.
1304 */
1305void pm_runtime_remove(struct device *dev)
1306{
1307 __pm_runtime_disable(dev, false);
1308
1309 /* Change the status back to 'suspended' to match the initial status. */
1310 if (dev->power.runtime_status == RPM_ACTIVE)
1311 pm_runtime_set_suspended(dev);
1312 if (dev->power.irq_safe && dev->parent)
1313 pm_runtime_put_sync(dev->parent);
1314}