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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/power/runtime.c - Helper functions for device runtime PM
4 *
5 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
6 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
7 */
8#include <linux/sched/mm.h>
9#include <linux/ktime.h>
10#include <linux/hrtimer.h>
11#include <linux/export.h>
12#include <linux/pm_runtime.h>
13#include <linux/pm_wakeirq.h>
14#include <trace/events/rpm.h>
15
16#include "../base.h"
17#include "power.h"
18
19typedef int (*pm_callback_t)(struct device *);
20
21static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
22{
23 pm_callback_t cb;
24 const struct dev_pm_ops *ops;
25
26 if (dev->pm_domain)
27 ops = &dev->pm_domain->ops;
28 else if (dev->type && dev->type->pm)
29 ops = dev->type->pm;
30 else if (dev->class && dev->class->pm)
31 ops = dev->class->pm;
32 else if (dev->bus && dev->bus->pm)
33 ops = dev->bus->pm;
34 else
35 ops = NULL;
36
37 if (ops)
38 cb = *(pm_callback_t *)((void *)ops + cb_offset);
39 else
40 cb = NULL;
41
42 if (!cb && dev->driver && dev->driver->pm)
43 cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
44
45 return cb;
46}
47
48#define RPM_GET_CALLBACK(dev, callback) \
49 __rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
50
51static int rpm_resume(struct device *dev, int rpmflags);
52static int rpm_suspend(struct device *dev, int rpmflags);
53
54/**
55 * update_pm_runtime_accounting - Update the time accounting of power states
56 * @dev: Device to update the accounting for
57 *
58 * In order to be able to have time accounting of the various power states
59 * (as used by programs such as PowerTOP to show the effectiveness of runtime
60 * PM), we need to track the time spent in each state.
61 * update_pm_runtime_accounting must be called each time before the
62 * runtime_status field is updated, to account the time in the old state
63 * correctly.
64 */
65static void update_pm_runtime_accounting(struct device *dev)
66{
67 u64 now, last, delta;
68
69 if (dev->power.disable_depth > 0)
70 return;
71
72 last = dev->power.accounting_timestamp;
73
74 now = ktime_get_mono_fast_ns();
75 dev->power.accounting_timestamp = now;
76
77 /*
78 * Because ktime_get_mono_fast_ns() is not monotonic during
79 * timekeeping updates, ensure that 'now' is after the last saved
80 * timesptamp.
81 */
82 if (now < last)
83 return;
84
85 delta = now - last;
86
87 if (dev->power.runtime_status == RPM_SUSPENDED)
88 dev->power.suspended_time += delta;
89 else
90 dev->power.active_time += delta;
91}
92
93static void __update_runtime_status(struct device *dev, enum rpm_status status)
94{
95 update_pm_runtime_accounting(dev);
96 dev->power.runtime_status = status;
97}
98
99static u64 rpm_get_accounted_time(struct device *dev, bool suspended)
100{
101 u64 time;
102 unsigned long flags;
103
104 spin_lock_irqsave(&dev->power.lock, flags);
105
106 update_pm_runtime_accounting(dev);
107 time = suspended ? dev->power.suspended_time : dev->power.active_time;
108
109 spin_unlock_irqrestore(&dev->power.lock, flags);
110
111 return time;
112}
113
114u64 pm_runtime_active_time(struct device *dev)
115{
116 return rpm_get_accounted_time(dev, false);
117}
118
119u64 pm_runtime_suspended_time(struct device *dev)
120{
121 return rpm_get_accounted_time(dev, true);
122}
123EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
124
125/**
126 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
127 * @dev: Device to handle.
128 */
129static void pm_runtime_deactivate_timer(struct device *dev)
130{
131 if (dev->power.timer_expires > 0) {
132 hrtimer_try_to_cancel(&dev->power.suspend_timer);
133 dev->power.timer_expires = 0;
134 }
135}
136
137/**
138 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
139 * @dev: Device to handle.
140 */
141static void pm_runtime_cancel_pending(struct device *dev)
142{
143 pm_runtime_deactivate_timer(dev);
144 /*
145 * In case there's a request pending, make sure its work function will
146 * return without doing anything.
147 */
148 dev->power.request = RPM_REQ_NONE;
149}
150
151/*
152 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
153 * @dev: Device to handle.
154 *
155 * Compute the autosuspend-delay expiration time based on the device's
156 * power.last_busy time. If the delay has already expired or is disabled
157 * (negative) or the power.use_autosuspend flag isn't set, return 0.
158 * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero).
159 *
160 * This function may be called either with or without dev->power.lock held.
161 * Either way it can be racy, since power.last_busy may be updated at any time.
162 */
163u64 pm_runtime_autosuspend_expiration(struct device *dev)
164{
165 int autosuspend_delay;
166 u64 expires;
167
168 if (!dev->power.use_autosuspend)
169 return 0;
170
171 autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
172 if (autosuspend_delay < 0)
173 return 0;
174
175 expires = READ_ONCE(dev->power.last_busy);
176 expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
177 if (expires > ktime_get_mono_fast_ns())
178 return expires; /* Expires in the future */
179
180 return 0;
181}
182EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
183
184static int dev_memalloc_noio(struct device *dev, void *data)
185{
186 return dev->power.memalloc_noio;
187}
188
189/*
190 * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
191 * @dev: Device to handle.
192 * @enable: True for setting the flag and False for clearing the flag.
193 *
194 * Set the flag for all devices in the path from the device to the
195 * root device in the device tree if @enable is true, otherwise clear
196 * the flag for devices in the path whose siblings don't set the flag.
197 *
198 * The function should only be called by block device, or network
199 * device driver for solving the deadlock problem during runtime
200 * resume/suspend:
201 *
202 * If memory allocation with GFP_KERNEL is called inside runtime
203 * resume/suspend callback of any one of its ancestors(or the
204 * block device itself), the deadlock may be triggered inside the
205 * memory allocation since it might not complete until the block
206 * device becomes active and the involed page I/O finishes. The
207 * situation is pointed out first by Alan Stern. Network device
208 * are involved in iSCSI kind of situation.
209 *
210 * The lock of dev_hotplug_mutex is held in the function for handling
211 * hotplug race because pm_runtime_set_memalloc_noio() may be called
212 * in async probe().
213 *
214 * The function should be called between device_add() and device_del()
215 * on the affected device(block/network device).
216 */
217void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
218{
219 static DEFINE_MUTEX(dev_hotplug_mutex);
220
221 mutex_lock(&dev_hotplug_mutex);
222 for (;;) {
223 bool enabled;
224
225 /* hold power lock since bitfield is not SMP-safe. */
226 spin_lock_irq(&dev->power.lock);
227 enabled = dev->power.memalloc_noio;
228 dev->power.memalloc_noio = enable;
229 spin_unlock_irq(&dev->power.lock);
230
231 /*
232 * not need to enable ancestors any more if the device
233 * has been enabled.
234 */
235 if (enabled && enable)
236 break;
237
238 dev = dev->parent;
239
240 /*
241 * clear flag of the parent device only if all the
242 * children don't set the flag because ancestor's
243 * flag was set by any one of the descendants.
244 */
245 if (!dev || (!enable &&
246 device_for_each_child(dev, NULL,
247 dev_memalloc_noio)))
248 break;
249 }
250 mutex_unlock(&dev_hotplug_mutex);
251}
252EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
253
254/**
255 * rpm_check_suspend_allowed - Test whether a device may be suspended.
256 * @dev: Device to test.
257 */
258static int rpm_check_suspend_allowed(struct device *dev)
259{
260 int retval = 0;
261
262 if (dev->power.runtime_error)
263 retval = -EINVAL;
264 else if (dev->power.disable_depth > 0)
265 retval = -EACCES;
266 else if (atomic_read(&dev->power.usage_count) > 0)
267 retval = -EAGAIN;
268 else if (!dev->power.ignore_children &&
269 atomic_read(&dev->power.child_count))
270 retval = -EBUSY;
271
272 /* Pending resume requests take precedence over suspends. */
273 else if ((dev->power.deferred_resume
274 && dev->power.runtime_status == RPM_SUSPENDING)
275 || (dev->power.request_pending
276 && dev->power.request == RPM_REQ_RESUME))
277 retval = -EAGAIN;
278 else if (__dev_pm_qos_resume_latency(dev) == 0)
279 retval = -EPERM;
280 else if (dev->power.runtime_status == RPM_SUSPENDED)
281 retval = 1;
282
283 return retval;
284}
285
286static int rpm_get_suppliers(struct device *dev)
287{
288 struct device_link *link;
289
290 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
291 device_links_read_lock_held()) {
292 int retval;
293
294 if (!(link->flags & DL_FLAG_PM_RUNTIME))
295 continue;
296
297 retval = pm_runtime_get_sync(link->supplier);
298 /* Ignore suppliers with disabled runtime PM. */
299 if (retval < 0 && retval != -EACCES) {
300 pm_runtime_put_noidle(link->supplier);
301 return retval;
302 }
303 refcount_inc(&link->rpm_active);
304 }
305 return 0;
306}
307
308static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
309{
310 struct device_link *link;
311
312 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
313 device_links_read_lock_held()) {
314
315 while (refcount_dec_not_one(&link->rpm_active))
316 pm_runtime_put_noidle(link->supplier);
317
318 if (try_to_suspend)
319 pm_request_idle(link->supplier);
320 }
321}
322
323static void rpm_put_suppliers(struct device *dev)
324{
325 __rpm_put_suppliers(dev, true);
326}
327
328static void rpm_suspend_suppliers(struct device *dev)
329{
330 struct device_link *link;
331 int idx = device_links_read_lock();
332
333 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
334 device_links_read_lock_held())
335 pm_request_idle(link->supplier);
336
337 device_links_read_unlock(idx);
338}
339
340/**
341 * __rpm_callback - Run a given runtime PM callback for a given device.
342 * @cb: Runtime PM callback to run.
343 * @dev: Device to run the callback for.
344 */
345static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
346 __releases(&dev->power.lock) __acquires(&dev->power.lock)
347{
348 int retval = 0, idx;
349 bool use_links = dev->power.links_count > 0;
350
351 if (dev->power.irq_safe) {
352 spin_unlock(&dev->power.lock);
353 } else {
354 spin_unlock_irq(&dev->power.lock);
355
356 /*
357 * Resume suppliers if necessary.
358 *
359 * The device's runtime PM status cannot change until this
360 * routine returns, so it is safe to read the status outside of
361 * the lock.
362 */
363 if (use_links && dev->power.runtime_status == RPM_RESUMING) {
364 idx = device_links_read_lock();
365
366 retval = rpm_get_suppliers(dev);
367 if (retval) {
368 rpm_put_suppliers(dev);
369 goto fail;
370 }
371
372 device_links_read_unlock(idx);
373 }
374 }
375
376 if (cb)
377 retval = cb(dev);
378
379 if (dev->power.irq_safe) {
380 spin_lock(&dev->power.lock);
381 } else {
382 /*
383 * If the device is suspending and the callback has returned
384 * success, drop the usage counters of the suppliers that have
385 * been reference counted on its resume.
386 *
387 * Do that if resume fails too.
388 */
389 if (use_links
390 && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
391 || (dev->power.runtime_status == RPM_RESUMING && retval))) {
392 idx = device_links_read_lock();
393
394 __rpm_put_suppliers(dev, false);
395
396fail:
397 device_links_read_unlock(idx);
398 }
399
400 spin_lock_irq(&dev->power.lock);
401 }
402
403 return retval;
404}
405
406/**
407 * rpm_idle - Notify device bus type if the device can be suspended.
408 * @dev: Device to notify the bus type about.
409 * @rpmflags: Flag bits.
410 *
411 * Check if the device's runtime PM status allows it to be suspended. If
412 * another idle notification has been started earlier, return immediately. If
413 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
414 * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
415 * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
416 *
417 * This function must be called under dev->power.lock with interrupts disabled.
418 */
419static int rpm_idle(struct device *dev, int rpmflags)
420{
421 int (*callback)(struct device *);
422 int retval;
423
424 trace_rpm_idle_rcuidle(dev, rpmflags);
425 retval = rpm_check_suspend_allowed(dev);
426 if (retval < 0)
427 ; /* Conditions are wrong. */
428
429 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
430 else if (dev->power.runtime_status != RPM_ACTIVE)
431 retval = -EAGAIN;
432
433 /*
434 * Any pending request other than an idle notification takes
435 * precedence over us, except that the timer may be running.
436 */
437 else if (dev->power.request_pending &&
438 dev->power.request > RPM_REQ_IDLE)
439 retval = -EAGAIN;
440
441 /* Act as though RPM_NOWAIT is always set. */
442 else if (dev->power.idle_notification)
443 retval = -EINPROGRESS;
444 if (retval)
445 goto out;
446
447 /* Pending requests need to be canceled. */
448 dev->power.request = RPM_REQ_NONE;
449
450 callback = RPM_GET_CALLBACK(dev, runtime_idle);
451
452 /* If no callback assume success. */
453 if (!callback || dev->power.no_callbacks)
454 goto out;
455
456 /* Carry out an asynchronous or a synchronous idle notification. */
457 if (rpmflags & RPM_ASYNC) {
458 dev->power.request = RPM_REQ_IDLE;
459 if (!dev->power.request_pending) {
460 dev->power.request_pending = true;
461 queue_work(pm_wq, &dev->power.work);
462 }
463 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
464 return 0;
465 }
466
467 dev->power.idle_notification = true;
468
469 retval = __rpm_callback(callback, dev);
470
471 dev->power.idle_notification = false;
472 wake_up_all(&dev->power.wait_queue);
473
474 out:
475 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
476 return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
477}
478
479/**
480 * rpm_callback - Run a given runtime PM callback for a given device.
481 * @cb: Runtime PM callback to run.
482 * @dev: Device to run the callback for.
483 */
484static int rpm_callback(int (*cb)(struct device *), struct device *dev)
485{
486 int retval;
487
488 if (dev->power.memalloc_noio) {
489 unsigned int noio_flag;
490
491 /*
492 * Deadlock might be caused if memory allocation with
493 * GFP_KERNEL happens inside runtime_suspend and
494 * runtime_resume callbacks of one block device's
495 * ancestor or the block device itself. Network
496 * device might be thought as part of iSCSI block
497 * device, so network device and its ancestor should
498 * be marked as memalloc_noio too.
499 */
500 noio_flag = memalloc_noio_save();
501 retval = __rpm_callback(cb, dev);
502 memalloc_noio_restore(noio_flag);
503 } else {
504 retval = __rpm_callback(cb, dev);
505 }
506
507 dev->power.runtime_error = retval;
508 return retval != -EACCES ? retval : -EIO;
509}
510
511/**
512 * rpm_suspend - Carry out runtime suspend of given device.
513 * @dev: Device to suspend.
514 * @rpmflags: Flag bits.
515 *
516 * Check if the device's runtime PM status allows it to be suspended.
517 * Cancel a pending idle notification, autosuspend or suspend. If
518 * another suspend has been started earlier, either return immediately
519 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
520 * flags. If the RPM_ASYNC flag is set then queue a suspend request;
521 * otherwise run the ->runtime_suspend() callback directly. When
522 * ->runtime_suspend succeeded, if a deferred resume was requested while
523 * the callback was running then carry it out, otherwise send an idle
524 * notification for its parent (if the suspend succeeded and both
525 * ignore_children of parent->power and irq_safe of dev->power are not set).
526 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
527 * flag is set and the next autosuspend-delay expiration time is in the
528 * future, schedule another autosuspend attempt.
529 *
530 * This function must be called under dev->power.lock with interrupts disabled.
531 */
532static int rpm_suspend(struct device *dev, int rpmflags)
533 __releases(&dev->power.lock) __acquires(&dev->power.lock)
534{
535 int (*callback)(struct device *);
536 struct device *parent = NULL;
537 int retval;
538
539 trace_rpm_suspend_rcuidle(dev, rpmflags);
540
541 repeat:
542 retval = rpm_check_suspend_allowed(dev);
543 if (retval < 0)
544 goto out; /* Conditions are wrong. */
545
546 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
547 if (dev->power.runtime_status == RPM_RESUMING && !(rpmflags & RPM_ASYNC))
548 retval = -EAGAIN;
549 if (retval)
550 goto out;
551
552 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
553 if ((rpmflags & RPM_AUTO)
554 && dev->power.runtime_status != RPM_SUSPENDING) {
555 u64 expires = pm_runtime_autosuspend_expiration(dev);
556
557 if (expires != 0) {
558 /* Pending requests need to be canceled. */
559 dev->power.request = RPM_REQ_NONE;
560
561 /*
562 * Optimization: If the timer is already running and is
563 * set to expire at or before the autosuspend delay,
564 * avoid the overhead of resetting it. Just let it
565 * expire; pm_suspend_timer_fn() will take care of the
566 * rest.
567 */
568 if (!(dev->power.timer_expires &&
569 dev->power.timer_expires <= expires)) {
570 /*
571 * We add a slack of 25% to gather wakeups
572 * without sacrificing the granularity.
573 */
574 u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) *
575 (NSEC_PER_MSEC >> 2);
576
577 dev->power.timer_expires = expires;
578 hrtimer_start_range_ns(&dev->power.suspend_timer,
579 ns_to_ktime(expires),
580 slack,
581 HRTIMER_MODE_ABS);
582 }
583 dev->power.timer_autosuspends = 1;
584 goto out;
585 }
586 }
587
588 /* Other scheduled or pending requests need to be canceled. */
589 pm_runtime_cancel_pending(dev);
590
591 if (dev->power.runtime_status == RPM_SUSPENDING) {
592 DEFINE_WAIT(wait);
593
594 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
595 retval = -EINPROGRESS;
596 goto out;
597 }
598
599 if (dev->power.irq_safe) {
600 spin_unlock(&dev->power.lock);
601
602 cpu_relax();
603
604 spin_lock(&dev->power.lock);
605 goto repeat;
606 }
607
608 /* Wait for the other suspend running in parallel with us. */
609 for (;;) {
610 prepare_to_wait(&dev->power.wait_queue, &wait,
611 TASK_UNINTERRUPTIBLE);
612 if (dev->power.runtime_status != RPM_SUSPENDING)
613 break;
614
615 spin_unlock_irq(&dev->power.lock);
616
617 schedule();
618
619 spin_lock_irq(&dev->power.lock);
620 }
621 finish_wait(&dev->power.wait_queue, &wait);
622 goto repeat;
623 }
624
625 if (dev->power.no_callbacks)
626 goto no_callback; /* Assume success. */
627
628 /* Carry out an asynchronous or a synchronous suspend. */
629 if (rpmflags & RPM_ASYNC) {
630 dev->power.request = (rpmflags & RPM_AUTO) ?
631 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
632 if (!dev->power.request_pending) {
633 dev->power.request_pending = true;
634 queue_work(pm_wq, &dev->power.work);
635 }
636 goto out;
637 }
638
639 __update_runtime_status(dev, RPM_SUSPENDING);
640
641 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
642
643 dev_pm_enable_wake_irq_check(dev, true);
644 retval = rpm_callback(callback, dev);
645 if (retval)
646 goto fail;
647
648 no_callback:
649 __update_runtime_status(dev, RPM_SUSPENDED);
650 pm_runtime_deactivate_timer(dev);
651
652 if (dev->parent) {
653 parent = dev->parent;
654 atomic_add_unless(&parent->power.child_count, -1, 0);
655 }
656 wake_up_all(&dev->power.wait_queue);
657
658 if (dev->power.deferred_resume) {
659 dev->power.deferred_resume = false;
660 rpm_resume(dev, 0);
661 retval = -EAGAIN;
662 goto out;
663 }
664
665 if (dev->power.irq_safe)
666 goto out;
667
668 /* Maybe the parent is now able to suspend. */
669 if (parent && !parent->power.ignore_children) {
670 spin_unlock(&dev->power.lock);
671
672 spin_lock(&parent->power.lock);
673 rpm_idle(parent, RPM_ASYNC);
674 spin_unlock(&parent->power.lock);
675
676 spin_lock(&dev->power.lock);
677 }
678 /* Maybe the suppliers are now able to suspend. */
679 if (dev->power.links_count > 0) {
680 spin_unlock_irq(&dev->power.lock);
681
682 rpm_suspend_suppliers(dev);
683
684 spin_lock_irq(&dev->power.lock);
685 }
686
687 out:
688 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
689
690 return retval;
691
692 fail:
693 dev_pm_disable_wake_irq_check(dev);
694 __update_runtime_status(dev, RPM_ACTIVE);
695 dev->power.deferred_resume = false;
696 wake_up_all(&dev->power.wait_queue);
697
698 if (retval == -EAGAIN || retval == -EBUSY) {
699 dev->power.runtime_error = 0;
700
701 /*
702 * If the callback routine failed an autosuspend, and
703 * if the last_busy time has been updated so that there
704 * is a new autosuspend expiration time, automatically
705 * reschedule another autosuspend.
706 */
707 if ((rpmflags & RPM_AUTO) &&
708 pm_runtime_autosuspend_expiration(dev) != 0)
709 goto repeat;
710 } else {
711 pm_runtime_cancel_pending(dev);
712 }
713 goto out;
714}
715
716/**
717 * rpm_resume - Carry out runtime resume of given device.
718 * @dev: Device to resume.
719 * @rpmflags: Flag bits.
720 *
721 * Check if the device's runtime PM status allows it to be resumed. Cancel
722 * any scheduled or pending requests. If another resume has been started
723 * earlier, either return immediately or wait for it to finish, depending on the
724 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
725 * parallel with this function, either tell the other process to resume after
726 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
727 * flag is set then queue a resume request; otherwise run the
728 * ->runtime_resume() callback directly. Queue an idle notification for the
729 * device if the resume succeeded.
730 *
731 * This function must be called under dev->power.lock with interrupts disabled.
732 */
733static int rpm_resume(struct device *dev, int rpmflags)
734 __releases(&dev->power.lock) __acquires(&dev->power.lock)
735{
736 int (*callback)(struct device *);
737 struct device *parent = NULL;
738 int retval = 0;
739
740 trace_rpm_resume_rcuidle(dev, rpmflags);
741
742 repeat:
743 if (dev->power.runtime_error)
744 retval = -EINVAL;
745 else if (dev->power.disable_depth == 1 && dev->power.is_suspended
746 && dev->power.runtime_status == RPM_ACTIVE)
747 retval = 1;
748 else if (dev->power.disable_depth > 0)
749 retval = -EACCES;
750 if (retval)
751 goto out;
752
753 /*
754 * Other scheduled or pending requests need to be canceled. Small
755 * optimization: If an autosuspend timer is running, leave it running
756 * rather than cancelling it now only to restart it again in the near
757 * future.
758 */
759 dev->power.request = RPM_REQ_NONE;
760 if (!dev->power.timer_autosuspends)
761 pm_runtime_deactivate_timer(dev);
762
763 if (dev->power.runtime_status == RPM_ACTIVE) {
764 retval = 1;
765 goto out;
766 }
767
768 if (dev->power.runtime_status == RPM_RESUMING
769 || dev->power.runtime_status == RPM_SUSPENDING) {
770 DEFINE_WAIT(wait);
771
772 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
773 if (dev->power.runtime_status == RPM_SUSPENDING)
774 dev->power.deferred_resume = true;
775 else
776 retval = -EINPROGRESS;
777 goto out;
778 }
779
780 if (dev->power.irq_safe) {
781 spin_unlock(&dev->power.lock);
782
783 cpu_relax();
784
785 spin_lock(&dev->power.lock);
786 goto repeat;
787 }
788
789 /* Wait for the operation carried out in parallel with us. */
790 for (;;) {
791 prepare_to_wait(&dev->power.wait_queue, &wait,
792 TASK_UNINTERRUPTIBLE);
793 if (dev->power.runtime_status != RPM_RESUMING
794 && dev->power.runtime_status != RPM_SUSPENDING)
795 break;
796
797 spin_unlock_irq(&dev->power.lock);
798
799 schedule();
800
801 spin_lock_irq(&dev->power.lock);
802 }
803 finish_wait(&dev->power.wait_queue, &wait);
804 goto repeat;
805 }
806
807 /*
808 * See if we can skip waking up the parent. This is safe only if
809 * power.no_callbacks is set, because otherwise we don't know whether
810 * the resume will actually succeed.
811 */
812 if (dev->power.no_callbacks && !parent && dev->parent) {
813 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
814 if (dev->parent->power.disable_depth > 0
815 || dev->parent->power.ignore_children
816 || dev->parent->power.runtime_status == RPM_ACTIVE) {
817 atomic_inc(&dev->parent->power.child_count);
818 spin_unlock(&dev->parent->power.lock);
819 retval = 1;
820 goto no_callback; /* Assume success. */
821 }
822 spin_unlock(&dev->parent->power.lock);
823 }
824
825 /* Carry out an asynchronous or a synchronous resume. */
826 if (rpmflags & RPM_ASYNC) {
827 dev->power.request = RPM_REQ_RESUME;
828 if (!dev->power.request_pending) {
829 dev->power.request_pending = true;
830 queue_work(pm_wq, &dev->power.work);
831 }
832 retval = 0;
833 goto out;
834 }
835
836 if (!parent && dev->parent) {
837 /*
838 * Increment the parent's usage counter and resume it if
839 * necessary. Not needed if dev is irq-safe; then the
840 * parent is permanently resumed.
841 */
842 parent = dev->parent;
843 if (dev->power.irq_safe)
844 goto skip_parent;
845 spin_unlock(&dev->power.lock);
846
847 pm_runtime_get_noresume(parent);
848
849 spin_lock(&parent->power.lock);
850 /*
851 * Resume the parent if it has runtime PM enabled and not been
852 * set to ignore its children.
853 */
854 if (!parent->power.disable_depth
855 && !parent->power.ignore_children) {
856 rpm_resume(parent, 0);
857 if (parent->power.runtime_status != RPM_ACTIVE)
858 retval = -EBUSY;
859 }
860 spin_unlock(&parent->power.lock);
861
862 spin_lock(&dev->power.lock);
863 if (retval)
864 goto out;
865 goto repeat;
866 }
867 skip_parent:
868
869 if (dev->power.no_callbacks)
870 goto no_callback; /* Assume success. */
871
872 __update_runtime_status(dev, RPM_RESUMING);
873
874 callback = RPM_GET_CALLBACK(dev, runtime_resume);
875
876 dev_pm_disable_wake_irq_check(dev);
877 retval = rpm_callback(callback, dev);
878 if (retval) {
879 __update_runtime_status(dev, RPM_SUSPENDED);
880 pm_runtime_cancel_pending(dev);
881 dev_pm_enable_wake_irq_check(dev, false);
882 } else {
883 no_callback:
884 __update_runtime_status(dev, RPM_ACTIVE);
885 pm_runtime_mark_last_busy(dev);
886 if (parent)
887 atomic_inc(&parent->power.child_count);
888 }
889 wake_up_all(&dev->power.wait_queue);
890
891 if (retval >= 0)
892 rpm_idle(dev, RPM_ASYNC);
893
894 out:
895 if (parent && !dev->power.irq_safe) {
896 spin_unlock_irq(&dev->power.lock);
897
898 pm_runtime_put(parent);
899
900 spin_lock_irq(&dev->power.lock);
901 }
902
903 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
904
905 return retval;
906}
907
908/**
909 * pm_runtime_work - Universal runtime PM work function.
910 * @work: Work structure used for scheduling the execution of this function.
911 *
912 * Use @work to get the device object the work is to be done for, determine what
913 * is to be done and execute the appropriate runtime PM function.
914 */
915static void pm_runtime_work(struct work_struct *work)
916{
917 struct device *dev = container_of(work, struct device, power.work);
918 enum rpm_request req;
919
920 spin_lock_irq(&dev->power.lock);
921
922 if (!dev->power.request_pending)
923 goto out;
924
925 req = dev->power.request;
926 dev->power.request = RPM_REQ_NONE;
927 dev->power.request_pending = false;
928
929 switch (req) {
930 case RPM_REQ_NONE:
931 break;
932 case RPM_REQ_IDLE:
933 rpm_idle(dev, RPM_NOWAIT);
934 break;
935 case RPM_REQ_SUSPEND:
936 rpm_suspend(dev, RPM_NOWAIT);
937 break;
938 case RPM_REQ_AUTOSUSPEND:
939 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
940 break;
941 case RPM_REQ_RESUME:
942 rpm_resume(dev, RPM_NOWAIT);
943 break;
944 }
945
946 out:
947 spin_unlock_irq(&dev->power.lock);
948}
949
950/**
951 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
952 * @timer: hrtimer used by pm_schedule_suspend().
953 *
954 * Check if the time is right and queue a suspend request.
955 */
956static enum hrtimer_restart pm_suspend_timer_fn(struct hrtimer *timer)
957{
958 struct device *dev = container_of(timer, struct device, power.suspend_timer);
959 unsigned long flags;
960 u64 expires;
961
962 spin_lock_irqsave(&dev->power.lock, flags);
963
964 expires = dev->power.timer_expires;
965 /*
966 * If 'expires' is after the current time, we've been called
967 * too early.
968 */
969 if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
970 dev->power.timer_expires = 0;
971 rpm_suspend(dev, dev->power.timer_autosuspends ?
972 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
973 }
974
975 spin_unlock_irqrestore(&dev->power.lock, flags);
976
977 return HRTIMER_NORESTART;
978}
979
980/**
981 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
982 * @dev: Device to suspend.
983 * @delay: Time to wait before submitting a suspend request, in milliseconds.
984 */
985int pm_schedule_suspend(struct device *dev, unsigned int delay)
986{
987 unsigned long flags;
988 u64 expires;
989 int retval;
990
991 spin_lock_irqsave(&dev->power.lock, flags);
992
993 if (!delay) {
994 retval = rpm_suspend(dev, RPM_ASYNC);
995 goto out;
996 }
997
998 retval = rpm_check_suspend_allowed(dev);
999 if (retval)
1000 goto out;
1001
1002 /* Other scheduled or pending requests need to be canceled. */
1003 pm_runtime_cancel_pending(dev);
1004
1005 expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC;
1006 dev->power.timer_expires = expires;
1007 dev->power.timer_autosuspends = 0;
1008 hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);
1009
1010 out:
1011 spin_unlock_irqrestore(&dev->power.lock, flags);
1012
1013 return retval;
1014}
1015EXPORT_SYMBOL_GPL(pm_schedule_suspend);
1016
1017/**
1018 * __pm_runtime_idle - Entry point for runtime idle operations.
1019 * @dev: Device to send idle notification for.
1020 * @rpmflags: Flag bits.
1021 *
1022 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1023 * return immediately if it is larger than zero. Then carry out an idle
1024 * notification, either synchronous or asynchronous.
1025 *
1026 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1027 * or if pm_runtime_irq_safe() has been called.
1028 */
1029int __pm_runtime_idle(struct device *dev, int rpmflags)
1030{
1031 unsigned long flags;
1032 int retval;
1033
1034 if (rpmflags & RPM_GET_PUT) {
1035 if (!atomic_dec_and_test(&dev->power.usage_count)) {
1036 trace_rpm_usage_rcuidle(dev, rpmflags);
1037 return 0;
1038 }
1039 }
1040
1041 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1042
1043 spin_lock_irqsave(&dev->power.lock, flags);
1044 retval = rpm_idle(dev, rpmflags);
1045 spin_unlock_irqrestore(&dev->power.lock, flags);
1046
1047 return retval;
1048}
1049EXPORT_SYMBOL_GPL(__pm_runtime_idle);
1050
1051/**
1052 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
1053 * @dev: Device to suspend.
1054 * @rpmflags: Flag bits.
1055 *
1056 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1057 * return immediately if it is larger than zero. Then carry out a suspend,
1058 * either synchronous or asynchronous.
1059 *
1060 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1061 * or if pm_runtime_irq_safe() has been called.
1062 */
1063int __pm_runtime_suspend(struct device *dev, int rpmflags)
1064{
1065 unsigned long flags;
1066 int retval;
1067
1068 if (rpmflags & RPM_GET_PUT) {
1069 if (!atomic_dec_and_test(&dev->power.usage_count)) {
1070 trace_rpm_usage_rcuidle(dev, rpmflags);
1071 return 0;
1072 }
1073 }
1074
1075 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1076
1077 spin_lock_irqsave(&dev->power.lock, flags);
1078 retval = rpm_suspend(dev, rpmflags);
1079 spin_unlock_irqrestore(&dev->power.lock, flags);
1080
1081 return retval;
1082}
1083EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
1084
1085/**
1086 * __pm_runtime_resume - Entry point for runtime resume operations.
1087 * @dev: Device to resume.
1088 * @rpmflags: Flag bits.
1089 *
1090 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
1091 * carry out a resume, either synchronous or asynchronous.
1092 *
1093 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1094 * or if pm_runtime_irq_safe() has been called.
1095 */
1096int __pm_runtime_resume(struct device *dev, int rpmflags)
1097{
1098 unsigned long flags;
1099 int retval;
1100
1101 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
1102 dev->power.runtime_status != RPM_ACTIVE);
1103
1104 if (rpmflags & RPM_GET_PUT)
1105 atomic_inc(&dev->power.usage_count);
1106
1107 spin_lock_irqsave(&dev->power.lock, flags);
1108 retval = rpm_resume(dev, rpmflags);
1109 spin_unlock_irqrestore(&dev->power.lock, flags);
1110
1111 return retval;
1112}
1113EXPORT_SYMBOL_GPL(__pm_runtime_resume);
1114
1115/**
1116 * pm_runtime_get_if_active - Conditionally bump up device usage counter.
1117 * @dev: Device to handle.
1118 * @ign_usage_count: Whether or not to look at the current usage counter value.
1119 *
1120 * Return -EINVAL if runtime PM is disabled for @dev.
1121 *
1122 * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either
1123 * @ign_usage_count is %true or the runtime PM usage counter of @dev is not
1124 * zero, increment the usage counter of @dev and return 1. Otherwise, return 0
1125 * without changing the usage counter.
1126 *
1127 * If @ign_usage_count is %true, this function can be used to prevent suspending
1128 * the device when its runtime PM status is %RPM_ACTIVE.
1129 *
1130 * If @ign_usage_count is %false, this function can be used to prevent
1131 * suspending the device when both its runtime PM status is %RPM_ACTIVE and its
1132 * runtime PM usage counter is not zero.
1133 *
1134 * The caller is responsible for decrementing the runtime PM usage counter of
1135 * @dev after this function has returned a positive value for it.
1136 */
1137int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
1138{
1139 unsigned long flags;
1140 int retval;
1141
1142 spin_lock_irqsave(&dev->power.lock, flags);
1143 if (dev->power.disable_depth > 0) {
1144 retval = -EINVAL;
1145 } else if (dev->power.runtime_status != RPM_ACTIVE) {
1146 retval = 0;
1147 } else if (ign_usage_count) {
1148 retval = 1;
1149 atomic_inc(&dev->power.usage_count);
1150 } else {
1151 retval = atomic_inc_not_zero(&dev->power.usage_count);
1152 }
1153 trace_rpm_usage_rcuidle(dev, 0);
1154 spin_unlock_irqrestore(&dev->power.lock, flags);
1155
1156 return retval;
1157}
1158EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
1159
1160/**
1161 * __pm_runtime_set_status - Set runtime PM status of a device.
1162 * @dev: Device to handle.
1163 * @status: New runtime PM status of the device.
1164 *
1165 * If runtime PM of the device is disabled or its power.runtime_error field is
1166 * different from zero, the status may be changed either to RPM_ACTIVE, or to
1167 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1168 * However, if the device has a parent and the parent is not active, and the
1169 * parent's power.ignore_children flag is unset, the device's status cannot be
1170 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1171 *
1172 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1173 * and the device parent's counter of unsuspended children is modified to
1174 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
1175 * notification request for the parent is submitted.
1176 *
1177 * If @dev has any suppliers (as reflected by device links to them), and @status
1178 * is RPM_ACTIVE, they will be activated upfront and if the activation of one
1179 * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead
1180 * of the @status value) and the suppliers will be deacticated on exit. The
1181 * error returned by the failing supplier activation will be returned in that
1182 * case.
1183 */
1184int __pm_runtime_set_status(struct device *dev, unsigned int status)
1185{
1186 struct device *parent = dev->parent;
1187 bool notify_parent = false;
1188 int error = 0;
1189
1190 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1191 return -EINVAL;
1192
1193 spin_lock_irq(&dev->power.lock);
1194
1195 /*
1196 * Prevent PM-runtime from being enabled for the device or return an
1197 * error if it is enabled already and working.
1198 */
1199 if (dev->power.runtime_error || dev->power.disable_depth)
1200 dev->power.disable_depth++;
1201 else
1202 error = -EAGAIN;
1203
1204 spin_unlock_irq(&dev->power.lock);
1205
1206 if (error)
1207 return error;
1208
1209 /*
1210 * If the new status is RPM_ACTIVE, the suppliers can be activated
1211 * upfront regardless of the current status, because next time
1212 * rpm_put_suppliers() runs, the rpm_active refcounts of the links
1213 * involved will be dropped down to one anyway.
1214 */
1215 if (status == RPM_ACTIVE) {
1216 int idx = device_links_read_lock();
1217
1218 error = rpm_get_suppliers(dev);
1219 if (error)
1220 status = RPM_SUSPENDED;
1221
1222 device_links_read_unlock(idx);
1223 }
1224
1225 spin_lock_irq(&dev->power.lock);
1226
1227 if (dev->power.runtime_status == status || !parent)
1228 goto out_set;
1229
1230 if (status == RPM_SUSPENDED) {
1231 atomic_add_unless(&parent->power.child_count, -1, 0);
1232 notify_parent = !parent->power.ignore_children;
1233 } else {
1234 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1235
1236 /*
1237 * It is invalid to put an active child under a parent that is
1238 * not active, has runtime PM enabled and the
1239 * 'power.ignore_children' flag unset.
1240 */
1241 if (!parent->power.disable_depth
1242 && !parent->power.ignore_children
1243 && parent->power.runtime_status != RPM_ACTIVE) {
1244 dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1245 dev_name(dev),
1246 dev_name(parent));
1247 error = -EBUSY;
1248 } else if (dev->power.runtime_status == RPM_SUSPENDED) {
1249 atomic_inc(&parent->power.child_count);
1250 }
1251
1252 spin_unlock(&parent->power.lock);
1253
1254 if (error) {
1255 status = RPM_SUSPENDED;
1256 goto out;
1257 }
1258 }
1259
1260 out_set:
1261 __update_runtime_status(dev, status);
1262 if (!error)
1263 dev->power.runtime_error = 0;
1264
1265 out:
1266 spin_unlock_irq(&dev->power.lock);
1267
1268 if (notify_parent)
1269 pm_request_idle(parent);
1270
1271 if (status == RPM_SUSPENDED) {
1272 int idx = device_links_read_lock();
1273
1274 rpm_put_suppliers(dev);
1275
1276 device_links_read_unlock(idx);
1277 }
1278
1279 pm_runtime_enable(dev);
1280
1281 return error;
1282}
1283EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1284
1285/**
1286 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1287 * @dev: Device to handle.
1288 *
1289 * Flush all pending requests for the device from pm_wq and wait for all
1290 * runtime PM operations involving the device in progress to complete.
1291 *
1292 * Should be called under dev->power.lock with interrupts disabled.
1293 */
1294static void __pm_runtime_barrier(struct device *dev)
1295{
1296 pm_runtime_deactivate_timer(dev);
1297
1298 if (dev->power.request_pending) {
1299 dev->power.request = RPM_REQ_NONE;
1300 spin_unlock_irq(&dev->power.lock);
1301
1302 cancel_work_sync(&dev->power.work);
1303
1304 spin_lock_irq(&dev->power.lock);
1305 dev->power.request_pending = false;
1306 }
1307
1308 if (dev->power.runtime_status == RPM_SUSPENDING
1309 || dev->power.runtime_status == RPM_RESUMING
1310 || dev->power.idle_notification) {
1311 DEFINE_WAIT(wait);
1312
1313 /* Suspend, wake-up or idle notification in progress. */
1314 for (;;) {
1315 prepare_to_wait(&dev->power.wait_queue, &wait,
1316 TASK_UNINTERRUPTIBLE);
1317 if (dev->power.runtime_status != RPM_SUSPENDING
1318 && dev->power.runtime_status != RPM_RESUMING
1319 && !dev->power.idle_notification)
1320 break;
1321 spin_unlock_irq(&dev->power.lock);
1322
1323 schedule();
1324
1325 spin_lock_irq(&dev->power.lock);
1326 }
1327 finish_wait(&dev->power.wait_queue, &wait);
1328 }
1329}
1330
1331/**
1332 * pm_runtime_barrier - Flush pending requests and wait for completions.
1333 * @dev: Device to handle.
1334 *
1335 * Prevent the device from being suspended by incrementing its usage counter and
1336 * if there's a pending resume request for the device, wake the device up.
1337 * Next, make sure that all pending requests for the device have been flushed
1338 * from pm_wq and wait for all runtime PM operations involving the device in
1339 * progress to complete.
1340 *
1341 * Return value:
1342 * 1, if there was a resume request pending and the device had to be woken up,
1343 * 0, otherwise
1344 */
1345int pm_runtime_barrier(struct device *dev)
1346{
1347 int retval = 0;
1348
1349 pm_runtime_get_noresume(dev);
1350 spin_lock_irq(&dev->power.lock);
1351
1352 if (dev->power.request_pending
1353 && dev->power.request == RPM_REQ_RESUME) {
1354 rpm_resume(dev, 0);
1355 retval = 1;
1356 }
1357
1358 __pm_runtime_barrier(dev);
1359
1360 spin_unlock_irq(&dev->power.lock);
1361 pm_runtime_put_noidle(dev);
1362
1363 return retval;
1364}
1365EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1366
1367/**
1368 * __pm_runtime_disable - Disable runtime PM of a device.
1369 * @dev: Device to handle.
1370 * @check_resume: If set, check if there's a resume request for the device.
1371 *
1372 * Increment power.disable_depth for the device and if it was zero previously,
1373 * cancel all pending runtime PM requests for the device and wait for all
1374 * operations in progress to complete. The device can be either active or
1375 * suspended after its runtime PM has been disabled.
1376 *
1377 * If @check_resume is set and there's a resume request pending when
1378 * __pm_runtime_disable() is called and power.disable_depth is zero, the
1379 * function will wake up the device before disabling its runtime PM.
1380 */
1381void __pm_runtime_disable(struct device *dev, bool check_resume)
1382{
1383 spin_lock_irq(&dev->power.lock);
1384
1385 if (dev->power.disable_depth > 0) {
1386 dev->power.disable_depth++;
1387 goto out;
1388 }
1389
1390 /*
1391 * Wake up the device if there's a resume request pending, because that
1392 * means there probably is some I/O to process and disabling runtime PM
1393 * shouldn't prevent the device from processing the I/O.
1394 */
1395 if (check_resume && dev->power.request_pending
1396 && dev->power.request == RPM_REQ_RESUME) {
1397 /*
1398 * Prevent suspends and idle notifications from being carried
1399 * out after we have woken up the device.
1400 */
1401 pm_runtime_get_noresume(dev);
1402
1403 rpm_resume(dev, 0);
1404
1405 pm_runtime_put_noidle(dev);
1406 }
1407
1408 /* Update time accounting before disabling PM-runtime. */
1409 update_pm_runtime_accounting(dev);
1410
1411 if (!dev->power.disable_depth++)
1412 __pm_runtime_barrier(dev);
1413
1414 out:
1415 spin_unlock_irq(&dev->power.lock);
1416}
1417EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1418
1419/**
1420 * pm_runtime_enable - Enable runtime PM of a device.
1421 * @dev: Device to handle.
1422 */
1423void pm_runtime_enable(struct device *dev)
1424{
1425 unsigned long flags;
1426
1427 spin_lock_irqsave(&dev->power.lock, flags);
1428
1429 if (dev->power.disable_depth > 0) {
1430 dev->power.disable_depth--;
1431
1432 /* About to enable runtime pm, set accounting_timestamp to now */
1433 if (!dev->power.disable_depth)
1434 dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
1435 } else {
1436 dev_warn(dev, "Unbalanced %s!\n", __func__);
1437 }
1438
1439 WARN(!dev->power.disable_depth &&
1440 dev->power.runtime_status == RPM_SUSPENDED &&
1441 !dev->power.ignore_children &&
1442 atomic_read(&dev->power.child_count) > 0,
1443 "Enabling runtime PM for inactive device (%s) with active children\n",
1444 dev_name(dev));
1445
1446 spin_unlock_irqrestore(&dev->power.lock, flags);
1447}
1448EXPORT_SYMBOL_GPL(pm_runtime_enable);
1449
1450/**
1451 * pm_runtime_forbid - Block runtime PM of a device.
1452 * @dev: Device to handle.
1453 *
1454 * Increase the device's usage count and clear its power.runtime_auto flag,
1455 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1456 * for it.
1457 */
1458void pm_runtime_forbid(struct device *dev)
1459{
1460 spin_lock_irq(&dev->power.lock);
1461 if (!dev->power.runtime_auto)
1462 goto out;
1463
1464 dev->power.runtime_auto = false;
1465 atomic_inc(&dev->power.usage_count);
1466 rpm_resume(dev, 0);
1467
1468 out:
1469 spin_unlock_irq(&dev->power.lock);
1470}
1471EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1472
1473/**
1474 * pm_runtime_allow - Unblock runtime PM of a device.
1475 * @dev: Device to handle.
1476 *
1477 * Decrease the device's usage count and set its power.runtime_auto flag.
1478 */
1479void pm_runtime_allow(struct device *dev)
1480{
1481 spin_lock_irq(&dev->power.lock);
1482 if (dev->power.runtime_auto)
1483 goto out;
1484
1485 dev->power.runtime_auto = true;
1486 if (atomic_dec_and_test(&dev->power.usage_count))
1487 rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1488 else
1489 trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC);
1490
1491 out:
1492 spin_unlock_irq(&dev->power.lock);
1493}
1494EXPORT_SYMBOL_GPL(pm_runtime_allow);
1495
1496/**
1497 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1498 * @dev: Device to handle.
1499 *
1500 * Set the power.no_callbacks flag, which tells the PM core that this
1501 * device is power-managed through its parent and has no runtime PM
1502 * callbacks of its own. The runtime sysfs attributes will be removed.
1503 */
1504void pm_runtime_no_callbacks(struct device *dev)
1505{
1506 spin_lock_irq(&dev->power.lock);
1507 dev->power.no_callbacks = 1;
1508 spin_unlock_irq(&dev->power.lock);
1509 if (device_is_registered(dev))
1510 rpm_sysfs_remove(dev);
1511}
1512EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1513
1514/**
1515 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1516 * @dev: Device to handle
1517 *
1518 * Set the power.irq_safe flag, which tells the PM core that the
1519 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1520 * always be invoked with the spinlock held and interrupts disabled. It also
1521 * causes the parent's usage counter to be permanently incremented, preventing
1522 * the parent from runtime suspending -- otherwise an irq-safe child might have
1523 * to wait for a non-irq-safe parent.
1524 */
1525void pm_runtime_irq_safe(struct device *dev)
1526{
1527 if (dev->parent)
1528 pm_runtime_get_sync(dev->parent);
1529 spin_lock_irq(&dev->power.lock);
1530 dev->power.irq_safe = 1;
1531 spin_unlock_irq(&dev->power.lock);
1532}
1533EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1534
1535/**
1536 * update_autosuspend - Handle a change to a device's autosuspend settings.
1537 * @dev: Device to handle.
1538 * @old_delay: The former autosuspend_delay value.
1539 * @old_use: The former use_autosuspend value.
1540 *
1541 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1542 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1543 *
1544 * This function must be called under dev->power.lock with interrupts disabled.
1545 */
1546static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1547{
1548 int delay = dev->power.autosuspend_delay;
1549
1550 /* Should runtime suspend be prevented now? */
1551 if (dev->power.use_autosuspend && delay < 0) {
1552
1553 /* If it used to be allowed then prevent it. */
1554 if (!old_use || old_delay >= 0) {
1555 atomic_inc(&dev->power.usage_count);
1556 rpm_resume(dev, 0);
1557 } else {
1558 trace_rpm_usage_rcuidle(dev, 0);
1559 }
1560 }
1561
1562 /* Runtime suspend should be allowed now. */
1563 else {
1564
1565 /* If it used to be prevented then allow it. */
1566 if (old_use && old_delay < 0)
1567 atomic_dec(&dev->power.usage_count);
1568
1569 /* Maybe we can autosuspend now. */
1570 rpm_idle(dev, RPM_AUTO);
1571 }
1572}
1573
1574/**
1575 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1576 * @dev: Device to handle.
1577 * @delay: Value of the new delay in milliseconds.
1578 *
1579 * Set the device's power.autosuspend_delay value. If it changes to negative
1580 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1581 * changes the other way, allow runtime suspends.
1582 */
1583void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1584{
1585 int old_delay, old_use;
1586
1587 spin_lock_irq(&dev->power.lock);
1588 old_delay = dev->power.autosuspend_delay;
1589 old_use = dev->power.use_autosuspend;
1590 dev->power.autosuspend_delay = delay;
1591 update_autosuspend(dev, old_delay, old_use);
1592 spin_unlock_irq(&dev->power.lock);
1593}
1594EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1595
1596/**
1597 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1598 * @dev: Device to handle.
1599 * @use: New value for use_autosuspend.
1600 *
1601 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1602 * suspends as needed.
1603 */
1604void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1605{
1606 int old_delay, old_use;
1607
1608 spin_lock_irq(&dev->power.lock);
1609 old_delay = dev->power.autosuspend_delay;
1610 old_use = dev->power.use_autosuspend;
1611 dev->power.use_autosuspend = use;
1612 update_autosuspend(dev, old_delay, old_use);
1613 spin_unlock_irq(&dev->power.lock);
1614}
1615EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1616
1617/**
1618 * pm_runtime_init - Initialize runtime PM fields in given device object.
1619 * @dev: Device object to initialize.
1620 */
1621void pm_runtime_init(struct device *dev)
1622{
1623 dev->power.runtime_status = RPM_SUSPENDED;
1624 dev->power.idle_notification = false;
1625
1626 dev->power.disable_depth = 1;
1627 atomic_set(&dev->power.usage_count, 0);
1628
1629 dev->power.runtime_error = 0;
1630
1631 atomic_set(&dev->power.child_count, 0);
1632 pm_suspend_ignore_children(dev, false);
1633 dev->power.runtime_auto = true;
1634
1635 dev->power.request_pending = false;
1636 dev->power.request = RPM_REQ_NONE;
1637 dev->power.deferred_resume = false;
1638 dev->power.needs_force_resume = 0;
1639 INIT_WORK(&dev->power.work, pm_runtime_work);
1640
1641 dev->power.timer_expires = 0;
1642 hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1643 dev->power.suspend_timer.function = pm_suspend_timer_fn;
1644
1645 init_waitqueue_head(&dev->power.wait_queue);
1646}
1647
1648/**
1649 * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1650 * @dev: Device object to re-initialize.
1651 */
1652void pm_runtime_reinit(struct device *dev)
1653{
1654 if (!pm_runtime_enabled(dev)) {
1655 if (dev->power.runtime_status == RPM_ACTIVE)
1656 pm_runtime_set_suspended(dev);
1657 if (dev->power.irq_safe) {
1658 spin_lock_irq(&dev->power.lock);
1659 dev->power.irq_safe = 0;
1660 spin_unlock_irq(&dev->power.lock);
1661 if (dev->parent)
1662 pm_runtime_put(dev->parent);
1663 }
1664 }
1665}
1666
1667/**
1668 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1669 * @dev: Device object being removed from device hierarchy.
1670 */
1671void pm_runtime_remove(struct device *dev)
1672{
1673 __pm_runtime_disable(dev, false);
1674 pm_runtime_reinit(dev);
1675}
1676
1677/**
1678 * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
1679 * @dev: Consumer device.
1680 */
1681void pm_runtime_get_suppliers(struct device *dev)
1682{
1683 struct device_link *link;
1684 int idx;
1685
1686 idx = device_links_read_lock();
1687
1688 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1689 device_links_read_lock_held())
1690 if (link->flags & DL_FLAG_PM_RUNTIME) {
1691 link->supplier_preactivated = true;
1692 pm_runtime_get_sync(link->supplier);
1693 refcount_inc(&link->rpm_active);
1694 }
1695
1696 device_links_read_unlock(idx);
1697}
1698
1699/**
1700 * pm_runtime_put_suppliers - Drop references to supplier devices.
1701 * @dev: Consumer device.
1702 */
1703void pm_runtime_put_suppliers(struct device *dev)
1704{
1705 struct device_link *link;
1706 unsigned long flags;
1707 bool put;
1708 int idx;
1709
1710 idx = device_links_read_lock();
1711
1712 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1713 device_links_read_lock_held())
1714 if (link->supplier_preactivated) {
1715 link->supplier_preactivated = false;
1716 spin_lock_irqsave(&dev->power.lock, flags);
1717 put = pm_runtime_status_suspended(dev) &&
1718 refcount_dec_not_one(&link->rpm_active);
1719 spin_unlock_irqrestore(&dev->power.lock, flags);
1720 if (put)
1721 pm_runtime_put(link->supplier);
1722 }
1723
1724 device_links_read_unlock(idx);
1725}
1726
1727void pm_runtime_new_link(struct device *dev)
1728{
1729 spin_lock_irq(&dev->power.lock);
1730 dev->power.links_count++;
1731 spin_unlock_irq(&dev->power.lock);
1732}
1733
1734static void pm_runtime_drop_link_count(struct device *dev)
1735{
1736 spin_lock_irq(&dev->power.lock);
1737 WARN_ON(dev->power.links_count == 0);
1738 dev->power.links_count--;
1739 spin_unlock_irq(&dev->power.lock);
1740}
1741
1742/**
1743 * pm_runtime_drop_link - Prepare for device link removal.
1744 * @link: Device link going away.
1745 *
1746 * Drop the link count of the consumer end of @link and decrement the supplier
1747 * device's runtime PM usage counter as many times as needed to drop all of the
1748 * PM runtime reference to it from the consumer.
1749 */
1750void pm_runtime_drop_link(struct device_link *link)
1751{
1752 if (!(link->flags & DL_FLAG_PM_RUNTIME))
1753 return;
1754
1755 pm_runtime_drop_link_count(link->consumer);
1756
1757 while (refcount_dec_not_one(&link->rpm_active))
1758 pm_runtime_put(link->supplier);
1759}
1760
1761static bool pm_runtime_need_not_resume(struct device *dev)
1762{
1763 return atomic_read(&dev->power.usage_count) <= 1 &&
1764 (atomic_read(&dev->power.child_count) == 0 ||
1765 dev->power.ignore_children);
1766}
1767
1768/**
1769 * pm_runtime_force_suspend - Force a device into suspend state if needed.
1770 * @dev: Device to suspend.
1771 *
1772 * Disable runtime PM so we safely can check the device's runtime PM status and
1773 * if it is active, invoke its ->runtime_suspend callback to suspend it and
1774 * change its runtime PM status field to RPM_SUSPENDED. Also, if the device's
1775 * usage and children counters don't indicate that the device was in use before
1776 * the system-wide transition under way, decrement its parent's children counter
1777 * (if there is a parent). Keep runtime PM disabled to preserve the state
1778 * unless we encounter errors.
1779 *
1780 * Typically this function may be invoked from a system suspend callback to make
1781 * sure the device is put into low power state and it should only be used during
1782 * system-wide PM transitions to sleep states. It assumes that the analogous
1783 * pm_runtime_force_resume() will be used to resume the device.
1784 */
1785int pm_runtime_force_suspend(struct device *dev)
1786{
1787 int (*callback)(struct device *);
1788 int ret;
1789
1790 pm_runtime_disable(dev);
1791 if (pm_runtime_status_suspended(dev))
1792 return 0;
1793
1794 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1795
1796 ret = callback ? callback(dev) : 0;
1797 if (ret)
1798 goto err;
1799
1800 /*
1801 * If the device can stay in suspend after the system-wide transition
1802 * to the working state that will follow, drop the children counter of
1803 * its parent, but set its status to RPM_SUSPENDED anyway in case this
1804 * function will be called again for it in the meantime.
1805 */
1806 if (pm_runtime_need_not_resume(dev)) {
1807 pm_runtime_set_suspended(dev);
1808 } else {
1809 __update_runtime_status(dev, RPM_SUSPENDED);
1810 dev->power.needs_force_resume = 1;
1811 }
1812
1813 return 0;
1814
1815err:
1816 pm_runtime_enable(dev);
1817 return ret;
1818}
1819EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1820
1821/**
1822 * pm_runtime_force_resume - Force a device into resume state if needed.
1823 * @dev: Device to resume.
1824 *
1825 * Prior invoking this function we expect the user to have brought the device
1826 * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1827 * those actions and bring the device into full power, if it is expected to be
1828 * used on system resume. In the other case, we defer the resume to be managed
1829 * via runtime PM.
1830 *
1831 * Typically this function may be invoked from a system resume callback.
1832 */
1833int pm_runtime_force_resume(struct device *dev)
1834{
1835 int (*callback)(struct device *);
1836 int ret = 0;
1837
1838 if (!pm_runtime_status_suspended(dev) || !dev->power.needs_force_resume)
1839 goto out;
1840
1841 /*
1842 * The value of the parent's children counter is correct already, so
1843 * just update the status of the device.
1844 */
1845 __update_runtime_status(dev, RPM_ACTIVE);
1846
1847 callback = RPM_GET_CALLBACK(dev, runtime_resume);
1848
1849 ret = callback ? callback(dev) : 0;
1850 if (ret) {
1851 pm_runtime_set_suspended(dev);
1852 goto out;
1853 }
1854
1855 pm_runtime_mark_last_busy(dev);
1856out:
1857 dev->power.needs_force_resume = 0;
1858 pm_runtime_enable(dev);
1859 return ret;
1860}
1861EXPORT_SYMBOL_GPL(pm_runtime_force_resume);