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1/*
2 * drivers/base/power/runtime.c - Helper functions for device runtime PM
3 *
4 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
6 *
7 * This file is released under the GPLv2.
8 */
9
10#include <linux/sched.h>
11#include <linux/pm_runtime.h>
12#include "power.h"
13
14static int rpm_resume(struct device *dev, int rpmflags);
15static int rpm_suspend(struct device *dev, int rpmflags);
16
17/**
18 * update_pm_runtime_accounting - Update the time accounting of power states
19 * @dev: Device to update the accounting for
20 *
21 * In order to be able to have time accounting of the various power states
22 * (as used by programs such as PowerTOP to show the effectiveness of runtime
23 * PM), we need to track the time spent in each state.
24 * update_pm_runtime_accounting must be called each time before the
25 * runtime_status field is updated, to account the time in the old state
26 * correctly.
27 */
28void update_pm_runtime_accounting(struct device *dev)
29{
30 unsigned long now = jiffies;
31 int delta;
32
33 delta = now - dev->power.accounting_timestamp;
34
35 if (delta < 0)
36 delta = 0;
37
38 dev->power.accounting_timestamp = now;
39
40 if (dev->power.disable_depth > 0)
41 return;
42
43 if (dev->power.runtime_status == RPM_SUSPENDED)
44 dev->power.suspended_jiffies += delta;
45 else
46 dev->power.active_jiffies += delta;
47}
48
49static void __update_runtime_status(struct device *dev, enum rpm_status status)
50{
51 update_pm_runtime_accounting(dev);
52 dev->power.runtime_status = status;
53}
54
55/**
56 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
57 * @dev: Device to handle.
58 */
59static void pm_runtime_deactivate_timer(struct device *dev)
60{
61 if (dev->power.timer_expires > 0) {
62 del_timer(&dev->power.suspend_timer);
63 dev->power.timer_expires = 0;
64 }
65}
66
67/**
68 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
69 * @dev: Device to handle.
70 */
71static void pm_runtime_cancel_pending(struct device *dev)
72{
73 pm_runtime_deactivate_timer(dev);
74 /*
75 * In case there's a request pending, make sure its work function will
76 * return without doing anything.
77 */
78 dev->power.request = RPM_REQ_NONE;
79}
80
81/*
82 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
83 * @dev: Device to handle.
84 *
85 * Compute the autosuspend-delay expiration time based on the device's
86 * power.last_busy time. If the delay has already expired or is disabled
87 * (negative) or the power.use_autosuspend flag isn't set, return 0.
88 * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
89 *
90 * This function may be called either with or without dev->power.lock held.
91 * Either way it can be racy, since power.last_busy may be updated at any time.
92 */
93unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
94{
95 int autosuspend_delay;
96 long elapsed;
97 unsigned long last_busy;
98 unsigned long expires = 0;
99
100 if (!dev->power.use_autosuspend)
101 goto out;
102
103 autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
104 if (autosuspend_delay < 0)
105 goto out;
106
107 last_busy = ACCESS_ONCE(dev->power.last_busy);
108 elapsed = jiffies - last_busy;
109 if (elapsed < 0)
110 goto out; /* jiffies has wrapped around. */
111
112 /*
113 * If the autosuspend_delay is >= 1 second, align the timer by rounding
114 * up to the nearest second.
115 */
116 expires = last_busy + msecs_to_jiffies(autosuspend_delay);
117 if (autosuspend_delay >= 1000)
118 expires = round_jiffies(expires);
119 expires += !expires;
120 if (elapsed >= expires - last_busy)
121 expires = 0; /* Already expired. */
122
123 out:
124 return expires;
125}
126EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
127
128/**
129 * rpm_check_suspend_allowed - Test whether a device may be suspended.
130 * @dev: Device to test.
131 */
132static int rpm_check_suspend_allowed(struct device *dev)
133{
134 int retval = 0;
135
136 if (dev->power.runtime_error)
137 retval = -EINVAL;
138 else if (dev->power.disable_depth > 0)
139 retval = -EACCES;
140 else if (atomic_read(&dev->power.usage_count) > 0)
141 retval = -EAGAIN;
142 else if (!pm_children_suspended(dev))
143 retval = -EBUSY;
144
145 /* Pending resume requests take precedence over suspends. */
146 else if ((dev->power.deferred_resume
147 && dev->power.runtime_status == RPM_SUSPENDING)
148 || (dev->power.request_pending
149 && dev->power.request == RPM_REQ_RESUME))
150 retval = -EAGAIN;
151 else if (dev->power.runtime_status == RPM_SUSPENDED)
152 retval = 1;
153
154 return retval;
155}
156
157/**
158 * rpm_idle - Notify device bus type if the device can be suspended.
159 * @dev: Device to notify the bus type about.
160 * @rpmflags: Flag bits.
161 *
162 * Check if the device's runtime PM status allows it to be suspended. If
163 * another idle notification has been started earlier, return immediately. If
164 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
165 * run the ->runtime_idle() callback directly.
166 *
167 * This function must be called under dev->power.lock with interrupts disabled.
168 */
169static int rpm_idle(struct device *dev, int rpmflags)
170{
171 int (*callback)(struct device *);
172 int retval;
173
174 retval = rpm_check_suspend_allowed(dev);
175 if (retval < 0)
176 ; /* Conditions are wrong. */
177
178 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
179 else if (dev->power.runtime_status != RPM_ACTIVE)
180 retval = -EAGAIN;
181
182 /*
183 * Any pending request other than an idle notification takes
184 * precedence over us, except that the timer may be running.
185 */
186 else if (dev->power.request_pending &&
187 dev->power.request > RPM_REQ_IDLE)
188 retval = -EAGAIN;
189
190 /* Act as though RPM_NOWAIT is always set. */
191 else if (dev->power.idle_notification)
192 retval = -EINPROGRESS;
193 if (retval)
194 goto out;
195
196 /* Pending requests need to be canceled. */
197 dev->power.request = RPM_REQ_NONE;
198
199 if (dev->power.no_callbacks) {
200 /* Assume ->runtime_idle() callback would have suspended. */
201 retval = rpm_suspend(dev, rpmflags);
202 goto out;
203 }
204
205 /* Carry out an asynchronous or a synchronous idle notification. */
206 if (rpmflags & RPM_ASYNC) {
207 dev->power.request = RPM_REQ_IDLE;
208 if (!dev->power.request_pending) {
209 dev->power.request_pending = true;
210 queue_work(pm_wq, &dev->power.work);
211 }
212 goto out;
213 }
214
215 dev->power.idle_notification = true;
216
217 if (dev->pm_domain)
218 callback = dev->pm_domain->ops.runtime_idle;
219 else if (dev->type && dev->type->pm)
220 callback = dev->type->pm->runtime_idle;
221 else if (dev->class && dev->class->pm)
222 callback = dev->class->pm->runtime_idle;
223 else if (dev->bus && dev->bus->pm)
224 callback = dev->bus->pm->runtime_idle;
225 else
226 callback = NULL;
227
228 if (callback) {
229 if (dev->power.irq_safe)
230 spin_unlock(&dev->power.lock);
231 else
232 spin_unlock_irq(&dev->power.lock);
233
234 callback(dev);
235
236 if (dev->power.irq_safe)
237 spin_lock(&dev->power.lock);
238 else
239 spin_lock_irq(&dev->power.lock);
240 }
241
242 dev->power.idle_notification = false;
243 wake_up_all(&dev->power.wait_queue);
244
245 out:
246 return retval;
247}
248
249/**
250 * rpm_callback - Run a given runtime PM callback for a given device.
251 * @cb: Runtime PM callback to run.
252 * @dev: Device to run the callback for.
253 */
254static int rpm_callback(int (*cb)(struct device *), struct device *dev)
255 __releases(&dev->power.lock) __acquires(&dev->power.lock)
256{
257 int retval;
258
259 if (!cb)
260 return -ENOSYS;
261
262 if (dev->power.irq_safe) {
263 retval = cb(dev);
264 } else {
265 spin_unlock_irq(&dev->power.lock);
266
267 retval = cb(dev);
268
269 spin_lock_irq(&dev->power.lock);
270 }
271 dev->power.runtime_error = retval;
272 return retval != -EACCES ? retval : -EIO;
273}
274
275/**
276 * rpm_suspend - Carry out runtime suspend of given device.
277 * @dev: Device to suspend.
278 * @rpmflags: Flag bits.
279 *
280 * Check if the device's runtime PM status allows it to be suspended. If
281 * another suspend has been started earlier, either return immediately or wait
282 * for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC flags. Cancel a
283 * pending idle notification. If the RPM_ASYNC flag is set then queue a
284 * suspend request; otherwise run the ->runtime_suspend() callback directly.
285 * If a deferred resume was requested while the callback was running then carry
286 * it out; otherwise send an idle notification for the device (if the suspend
287 * failed) or for its parent (if the suspend succeeded).
288 *
289 * This function must be called under dev->power.lock with interrupts disabled.
290 */
291static int rpm_suspend(struct device *dev, int rpmflags)
292 __releases(&dev->power.lock) __acquires(&dev->power.lock)
293{
294 int (*callback)(struct device *);
295 struct device *parent = NULL;
296 int retval;
297
298 dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
299
300 repeat:
301 retval = rpm_check_suspend_allowed(dev);
302
303 if (retval < 0)
304 ; /* Conditions are wrong. */
305
306 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
307 else if (dev->power.runtime_status == RPM_RESUMING &&
308 !(rpmflags & RPM_ASYNC))
309 retval = -EAGAIN;
310 if (retval)
311 goto out;
312
313 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
314 if ((rpmflags & RPM_AUTO)
315 && dev->power.runtime_status != RPM_SUSPENDING) {
316 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
317
318 if (expires != 0) {
319 /* Pending requests need to be canceled. */
320 dev->power.request = RPM_REQ_NONE;
321
322 /*
323 * Optimization: If the timer is already running and is
324 * set to expire at or before the autosuspend delay,
325 * avoid the overhead of resetting it. Just let it
326 * expire; pm_suspend_timer_fn() will take care of the
327 * rest.
328 */
329 if (!(dev->power.timer_expires && time_before_eq(
330 dev->power.timer_expires, expires))) {
331 dev->power.timer_expires = expires;
332 mod_timer(&dev->power.suspend_timer, expires);
333 }
334 dev->power.timer_autosuspends = 1;
335 goto out;
336 }
337 }
338
339 /* Other scheduled or pending requests need to be canceled. */
340 pm_runtime_cancel_pending(dev);
341
342 if (dev->power.runtime_status == RPM_SUSPENDING) {
343 DEFINE_WAIT(wait);
344
345 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
346 retval = -EINPROGRESS;
347 goto out;
348 }
349
350 /* Wait for the other suspend running in parallel with us. */
351 for (;;) {
352 prepare_to_wait(&dev->power.wait_queue, &wait,
353 TASK_UNINTERRUPTIBLE);
354 if (dev->power.runtime_status != RPM_SUSPENDING)
355 break;
356
357 spin_unlock_irq(&dev->power.lock);
358
359 schedule();
360
361 spin_lock_irq(&dev->power.lock);
362 }
363 finish_wait(&dev->power.wait_queue, &wait);
364 goto repeat;
365 }
366
367 dev->power.deferred_resume = false;
368 if (dev->power.no_callbacks)
369 goto no_callback; /* Assume success. */
370
371 /* Carry out an asynchronous or a synchronous suspend. */
372 if (rpmflags & RPM_ASYNC) {
373 dev->power.request = (rpmflags & RPM_AUTO) ?
374 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
375 if (!dev->power.request_pending) {
376 dev->power.request_pending = true;
377 queue_work(pm_wq, &dev->power.work);
378 }
379 goto out;
380 }
381
382 __update_runtime_status(dev, RPM_SUSPENDING);
383
384 if (dev->pm_domain)
385 callback = dev->pm_domain->ops.runtime_suspend;
386 else if (dev->type && dev->type->pm)
387 callback = dev->type->pm->runtime_suspend;
388 else if (dev->class && dev->class->pm)
389 callback = dev->class->pm->runtime_suspend;
390 else if (dev->bus && dev->bus->pm)
391 callback = dev->bus->pm->runtime_suspend;
392 else
393 callback = NULL;
394
395 retval = rpm_callback(callback, dev);
396 if (retval) {
397 __update_runtime_status(dev, RPM_ACTIVE);
398 dev->power.deferred_resume = false;
399 if (retval == -EAGAIN || retval == -EBUSY)
400 dev->power.runtime_error = 0;
401 else
402 pm_runtime_cancel_pending(dev);
403 } else {
404 no_callback:
405 __update_runtime_status(dev, RPM_SUSPENDED);
406 pm_runtime_deactivate_timer(dev);
407
408 if (dev->parent) {
409 parent = dev->parent;
410 atomic_add_unless(&parent->power.child_count, -1, 0);
411 }
412 }
413 wake_up_all(&dev->power.wait_queue);
414
415 if (dev->power.deferred_resume) {
416 rpm_resume(dev, 0);
417 retval = -EAGAIN;
418 goto out;
419 }
420
421 /* Maybe the parent is now able to suspend. */
422 if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
423 spin_unlock(&dev->power.lock);
424
425 spin_lock(&parent->power.lock);
426 rpm_idle(parent, RPM_ASYNC);
427 spin_unlock(&parent->power.lock);
428
429 spin_lock(&dev->power.lock);
430 }
431
432 out:
433 dev_dbg(dev, "%s returns %d\n", __func__, retval);
434
435 return retval;
436}
437
438/**
439 * rpm_resume - Carry out runtime resume of given device.
440 * @dev: Device to resume.
441 * @rpmflags: Flag bits.
442 *
443 * Check if the device's runtime PM status allows it to be resumed. Cancel
444 * any scheduled or pending requests. If another resume has been started
445 * earlier, either return immediately or wait for it to finish, depending on the
446 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
447 * parallel with this function, either tell the other process to resume after
448 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
449 * flag is set then queue a resume request; otherwise run the
450 * ->runtime_resume() callback directly. Queue an idle notification for the
451 * device if the resume succeeded.
452 *
453 * This function must be called under dev->power.lock with interrupts disabled.
454 */
455static int rpm_resume(struct device *dev, int rpmflags)
456 __releases(&dev->power.lock) __acquires(&dev->power.lock)
457{
458 int (*callback)(struct device *);
459 struct device *parent = NULL;
460 int retval = 0;
461
462 dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
463
464 repeat:
465 if (dev->power.runtime_error)
466 retval = -EINVAL;
467 else if (dev->power.disable_depth > 0)
468 retval = -EACCES;
469 if (retval)
470 goto out;
471
472 /*
473 * Other scheduled or pending requests need to be canceled. Small
474 * optimization: If an autosuspend timer is running, leave it running
475 * rather than cancelling it now only to restart it again in the near
476 * future.
477 */
478 dev->power.request = RPM_REQ_NONE;
479 if (!dev->power.timer_autosuspends)
480 pm_runtime_deactivate_timer(dev);
481
482 if (dev->power.runtime_status == RPM_ACTIVE) {
483 retval = 1;
484 goto out;
485 }
486
487 if (dev->power.runtime_status == RPM_RESUMING
488 || dev->power.runtime_status == RPM_SUSPENDING) {
489 DEFINE_WAIT(wait);
490
491 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
492 if (dev->power.runtime_status == RPM_SUSPENDING)
493 dev->power.deferred_resume = true;
494 else
495 retval = -EINPROGRESS;
496 goto out;
497 }
498
499 /* Wait for the operation carried out in parallel with us. */
500 for (;;) {
501 prepare_to_wait(&dev->power.wait_queue, &wait,
502 TASK_UNINTERRUPTIBLE);
503 if (dev->power.runtime_status != RPM_RESUMING
504 && dev->power.runtime_status != RPM_SUSPENDING)
505 break;
506
507 spin_unlock_irq(&dev->power.lock);
508
509 schedule();
510
511 spin_lock_irq(&dev->power.lock);
512 }
513 finish_wait(&dev->power.wait_queue, &wait);
514 goto repeat;
515 }
516
517 /*
518 * See if we can skip waking up the parent. This is safe only if
519 * power.no_callbacks is set, because otherwise we don't know whether
520 * the resume will actually succeed.
521 */
522 if (dev->power.no_callbacks && !parent && dev->parent) {
523 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
524 if (dev->parent->power.disable_depth > 0
525 || dev->parent->power.ignore_children
526 || dev->parent->power.runtime_status == RPM_ACTIVE) {
527 atomic_inc(&dev->parent->power.child_count);
528 spin_unlock(&dev->parent->power.lock);
529 goto no_callback; /* Assume success. */
530 }
531 spin_unlock(&dev->parent->power.lock);
532 }
533
534 /* Carry out an asynchronous or a synchronous resume. */
535 if (rpmflags & RPM_ASYNC) {
536 dev->power.request = RPM_REQ_RESUME;
537 if (!dev->power.request_pending) {
538 dev->power.request_pending = true;
539 queue_work(pm_wq, &dev->power.work);
540 }
541 retval = 0;
542 goto out;
543 }
544
545 if (!parent && dev->parent) {
546 /*
547 * Increment the parent's usage counter and resume it if
548 * necessary. Not needed if dev is irq-safe; then the
549 * parent is permanently resumed.
550 */
551 parent = dev->parent;
552 if (dev->power.irq_safe)
553 goto skip_parent;
554 spin_unlock(&dev->power.lock);
555
556 pm_runtime_get_noresume(parent);
557
558 spin_lock(&parent->power.lock);
559 /*
560 * We can resume if the parent's runtime PM is disabled or it
561 * is set to ignore children.
562 */
563 if (!parent->power.disable_depth
564 && !parent->power.ignore_children) {
565 rpm_resume(parent, 0);
566 if (parent->power.runtime_status != RPM_ACTIVE)
567 retval = -EBUSY;
568 }
569 spin_unlock(&parent->power.lock);
570
571 spin_lock(&dev->power.lock);
572 if (retval)
573 goto out;
574 goto repeat;
575 }
576 skip_parent:
577
578 if (dev->power.no_callbacks)
579 goto no_callback; /* Assume success. */
580
581 __update_runtime_status(dev, RPM_RESUMING);
582
583 if (dev->pm_domain)
584 callback = dev->pm_domain->ops.runtime_resume;
585 else if (dev->type && dev->type->pm)
586 callback = dev->type->pm->runtime_resume;
587 else if (dev->class && dev->class->pm)
588 callback = dev->class->pm->runtime_resume;
589 else if (dev->bus && dev->bus->pm)
590 callback = dev->bus->pm->runtime_resume;
591 else
592 callback = NULL;
593
594 retval = rpm_callback(callback, dev);
595 if (retval) {
596 __update_runtime_status(dev, RPM_SUSPENDED);
597 pm_runtime_cancel_pending(dev);
598 } else {
599 no_callback:
600 __update_runtime_status(dev, RPM_ACTIVE);
601 if (parent)
602 atomic_inc(&parent->power.child_count);
603 }
604 wake_up_all(&dev->power.wait_queue);
605
606 if (!retval)
607 rpm_idle(dev, RPM_ASYNC);
608
609 out:
610 if (parent && !dev->power.irq_safe) {
611 spin_unlock_irq(&dev->power.lock);
612
613 pm_runtime_put(parent);
614
615 spin_lock_irq(&dev->power.lock);
616 }
617
618 dev_dbg(dev, "%s returns %d\n", __func__, retval);
619
620 return retval;
621}
622
623/**
624 * pm_runtime_work - Universal runtime PM work function.
625 * @work: Work structure used for scheduling the execution of this function.
626 *
627 * Use @work to get the device object the work is to be done for, determine what
628 * is to be done and execute the appropriate runtime PM function.
629 */
630static void pm_runtime_work(struct work_struct *work)
631{
632 struct device *dev = container_of(work, struct device, power.work);
633 enum rpm_request req;
634
635 spin_lock_irq(&dev->power.lock);
636
637 if (!dev->power.request_pending)
638 goto out;
639
640 req = dev->power.request;
641 dev->power.request = RPM_REQ_NONE;
642 dev->power.request_pending = false;
643
644 switch (req) {
645 case RPM_REQ_NONE:
646 break;
647 case RPM_REQ_IDLE:
648 rpm_idle(dev, RPM_NOWAIT);
649 break;
650 case RPM_REQ_SUSPEND:
651 rpm_suspend(dev, RPM_NOWAIT);
652 break;
653 case RPM_REQ_AUTOSUSPEND:
654 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
655 break;
656 case RPM_REQ_RESUME:
657 rpm_resume(dev, RPM_NOWAIT);
658 break;
659 }
660
661 out:
662 spin_unlock_irq(&dev->power.lock);
663}
664
665/**
666 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
667 * @data: Device pointer passed by pm_schedule_suspend().
668 *
669 * Check if the time is right and queue a suspend request.
670 */
671static void pm_suspend_timer_fn(unsigned long data)
672{
673 struct device *dev = (struct device *)data;
674 unsigned long flags;
675 unsigned long expires;
676
677 spin_lock_irqsave(&dev->power.lock, flags);
678
679 expires = dev->power.timer_expires;
680 /* If 'expire' is after 'jiffies' we've been called too early. */
681 if (expires > 0 && !time_after(expires, jiffies)) {
682 dev->power.timer_expires = 0;
683 rpm_suspend(dev, dev->power.timer_autosuspends ?
684 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
685 }
686
687 spin_unlock_irqrestore(&dev->power.lock, flags);
688}
689
690/**
691 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
692 * @dev: Device to suspend.
693 * @delay: Time to wait before submitting a suspend request, in milliseconds.
694 */
695int pm_schedule_suspend(struct device *dev, unsigned int delay)
696{
697 unsigned long flags;
698 int retval;
699
700 spin_lock_irqsave(&dev->power.lock, flags);
701
702 if (!delay) {
703 retval = rpm_suspend(dev, RPM_ASYNC);
704 goto out;
705 }
706
707 retval = rpm_check_suspend_allowed(dev);
708 if (retval)
709 goto out;
710
711 /* Other scheduled or pending requests need to be canceled. */
712 pm_runtime_cancel_pending(dev);
713
714 dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
715 dev->power.timer_expires += !dev->power.timer_expires;
716 dev->power.timer_autosuspends = 0;
717 mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
718
719 out:
720 spin_unlock_irqrestore(&dev->power.lock, flags);
721
722 return retval;
723}
724EXPORT_SYMBOL_GPL(pm_schedule_suspend);
725
726/**
727 * __pm_runtime_idle - Entry point for runtime idle operations.
728 * @dev: Device to send idle notification for.
729 * @rpmflags: Flag bits.
730 *
731 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
732 * return immediately if it is larger than zero. Then carry out an idle
733 * notification, either synchronous or asynchronous.
734 *
735 * This routine may be called in atomic context if the RPM_ASYNC flag is set.
736 */
737int __pm_runtime_idle(struct device *dev, int rpmflags)
738{
739 unsigned long flags;
740 int retval;
741
742 if (rpmflags & RPM_GET_PUT) {
743 if (!atomic_dec_and_test(&dev->power.usage_count))
744 return 0;
745 }
746
747 spin_lock_irqsave(&dev->power.lock, flags);
748 retval = rpm_idle(dev, rpmflags);
749 spin_unlock_irqrestore(&dev->power.lock, flags);
750
751 return retval;
752}
753EXPORT_SYMBOL_GPL(__pm_runtime_idle);
754
755/**
756 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
757 * @dev: Device to suspend.
758 * @rpmflags: Flag bits.
759 *
760 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
761 * return immediately if it is larger than zero. Then carry out a suspend,
762 * either synchronous or asynchronous.
763 *
764 * This routine may be called in atomic context if the RPM_ASYNC flag is set.
765 */
766int __pm_runtime_suspend(struct device *dev, int rpmflags)
767{
768 unsigned long flags;
769 int retval;
770
771 if (rpmflags & RPM_GET_PUT) {
772 if (!atomic_dec_and_test(&dev->power.usage_count))
773 return 0;
774 }
775
776 spin_lock_irqsave(&dev->power.lock, flags);
777 retval = rpm_suspend(dev, rpmflags);
778 spin_unlock_irqrestore(&dev->power.lock, flags);
779
780 return retval;
781}
782EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
783
784/**
785 * __pm_runtime_resume - Entry point for runtime resume operations.
786 * @dev: Device to resume.
787 * @rpmflags: Flag bits.
788 *
789 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
790 * carry out a resume, either synchronous or asynchronous.
791 *
792 * This routine may be called in atomic context if the RPM_ASYNC flag is set.
793 */
794int __pm_runtime_resume(struct device *dev, int rpmflags)
795{
796 unsigned long flags;
797 int retval;
798
799 if (rpmflags & RPM_GET_PUT)
800 atomic_inc(&dev->power.usage_count);
801
802 spin_lock_irqsave(&dev->power.lock, flags);
803 retval = rpm_resume(dev, rpmflags);
804 spin_unlock_irqrestore(&dev->power.lock, flags);
805
806 return retval;
807}
808EXPORT_SYMBOL_GPL(__pm_runtime_resume);
809
810/**
811 * __pm_runtime_set_status - Set runtime PM status of a device.
812 * @dev: Device to handle.
813 * @status: New runtime PM status of the device.
814 *
815 * If runtime PM of the device is disabled or its power.runtime_error field is
816 * different from zero, the status may be changed either to RPM_ACTIVE, or to
817 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
818 * However, if the device has a parent and the parent is not active, and the
819 * parent's power.ignore_children flag is unset, the device's status cannot be
820 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
821 *
822 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
823 * and the device parent's counter of unsuspended children is modified to
824 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
825 * notification request for the parent is submitted.
826 */
827int __pm_runtime_set_status(struct device *dev, unsigned int status)
828{
829 struct device *parent = dev->parent;
830 unsigned long flags;
831 bool notify_parent = false;
832 int error = 0;
833
834 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
835 return -EINVAL;
836
837 spin_lock_irqsave(&dev->power.lock, flags);
838
839 if (!dev->power.runtime_error && !dev->power.disable_depth) {
840 error = -EAGAIN;
841 goto out;
842 }
843
844 if (dev->power.runtime_status == status)
845 goto out_set;
846
847 if (status == RPM_SUSPENDED) {
848 /* It always is possible to set the status to 'suspended'. */
849 if (parent) {
850 atomic_add_unless(&parent->power.child_count, -1, 0);
851 notify_parent = !parent->power.ignore_children;
852 }
853 goto out_set;
854 }
855
856 if (parent) {
857 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
858
859 /*
860 * It is invalid to put an active child under a parent that is
861 * not active, has runtime PM enabled and the
862 * 'power.ignore_children' flag unset.
863 */
864 if (!parent->power.disable_depth
865 && !parent->power.ignore_children
866 && parent->power.runtime_status != RPM_ACTIVE)
867 error = -EBUSY;
868 else if (dev->power.runtime_status == RPM_SUSPENDED)
869 atomic_inc(&parent->power.child_count);
870
871 spin_unlock(&parent->power.lock);
872
873 if (error)
874 goto out;
875 }
876
877 out_set:
878 __update_runtime_status(dev, status);
879 dev->power.runtime_error = 0;
880 out:
881 spin_unlock_irqrestore(&dev->power.lock, flags);
882
883 if (notify_parent)
884 pm_request_idle(parent);
885
886 return error;
887}
888EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
889
890/**
891 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
892 * @dev: Device to handle.
893 *
894 * Flush all pending requests for the device from pm_wq and wait for all
895 * runtime PM operations involving the device in progress to complete.
896 *
897 * Should be called under dev->power.lock with interrupts disabled.
898 */
899static void __pm_runtime_barrier(struct device *dev)
900{
901 pm_runtime_deactivate_timer(dev);
902
903 if (dev->power.request_pending) {
904 dev->power.request = RPM_REQ_NONE;
905 spin_unlock_irq(&dev->power.lock);
906
907 cancel_work_sync(&dev->power.work);
908
909 spin_lock_irq(&dev->power.lock);
910 dev->power.request_pending = false;
911 }
912
913 if (dev->power.runtime_status == RPM_SUSPENDING
914 || dev->power.runtime_status == RPM_RESUMING
915 || dev->power.idle_notification) {
916 DEFINE_WAIT(wait);
917
918 /* Suspend, wake-up or idle notification in progress. */
919 for (;;) {
920 prepare_to_wait(&dev->power.wait_queue, &wait,
921 TASK_UNINTERRUPTIBLE);
922 if (dev->power.runtime_status != RPM_SUSPENDING
923 && dev->power.runtime_status != RPM_RESUMING
924 && !dev->power.idle_notification)
925 break;
926 spin_unlock_irq(&dev->power.lock);
927
928 schedule();
929
930 spin_lock_irq(&dev->power.lock);
931 }
932 finish_wait(&dev->power.wait_queue, &wait);
933 }
934}
935
936/**
937 * pm_runtime_barrier - Flush pending requests and wait for completions.
938 * @dev: Device to handle.
939 *
940 * Prevent the device from being suspended by incrementing its usage counter and
941 * if there's a pending resume request for the device, wake the device up.
942 * Next, make sure that all pending requests for the device have been flushed
943 * from pm_wq and wait for all runtime PM operations involving the device in
944 * progress to complete.
945 *
946 * Return value:
947 * 1, if there was a resume request pending and the device had to be woken up,
948 * 0, otherwise
949 */
950int pm_runtime_barrier(struct device *dev)
951{
952 int retval = 0;
953
954 pm_runtime_get_noresume(dev);
955 spin_lock_irq(&dev->power.lock);
956
957 if (dev->power.request_pending
958 && dev->power.request == RPM_REQ_RESUME) {
959 rpm_resume(dev, 0);
960 retval = 1;
961 }
962
963 __pm_runtime_barrier(dev);
964
965 spin_unlock_irq(&dev->power.lock);
966 pm_runtime_put_noidle(dev);
967
968 return retval;
969}
970EXPORT_SYMBOL_GPL(pm_runtime_barrier);
971
972/**
973 * __pm_runtime_disable - Disable runtime PM of a device.
974 * @dev: Device to handle.
975 * @check_resume: If set, check if there's a resume request for the device.
976 *
977 * Increment power.disable_depth for the device and if was zero previously,
978 * cancel all pending runtime PM requests for the device and wait for all
979 * operations in progress to complete. The device can be either active or
980 * suspended after its runtime PM has been disabled.
981 *
982 * If @check_resume is set and there's a resume request pending when
983 * __pm_runtime_disable() is called and power.disable_depth is zero, the
984 * function will wake up the device before disabling its runtime PM.
985 */
986void __pm_runtime_disable(struct device *dev, bool check_resume)
987{
988 spin_lock_irq(&dev->power.lock);
989
990 if (dev->power.disable_depth > 0) {
991 dev->power.disable_depth++;
992 goto out;
993 }
994
995 /*
996 * Wake up the device if there's a resume request pending, because that
997 * means there probably is some I/O to process and disabling runtime PM
998 * shouldn't prevent the device from processing the I/O.
999 */
1000 if (check_resume && dev->power.request_pending
1001 && dev->power.request == RPM_REQ_RESUME) {
1002 /*
1003 * Prevent suspends and idle notifications from being carried
1004 * out after we have woken up the device.
1005 */
1006 pm_runtime_get_noresume(dev);
1007
1008 rpm_resume(dev, 0);
1009
1010 pm_runtime_put_noidle(dev);
1011 }
1012
1013 if (!dev->power.disable_depth++)
1014 __pm_runtime_barrier(dev);
1015
1016 out:
1017 spin_unlock_irq(&dev->power.lock);
1018}
1019EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1020
1021/**
1022 * pm_runtime_enable - Enable runtime PM of a device.
1023 * @dev: Device to handle.
1024 */
1025void pm_runtime_enable(struct device *dev)
1026{
1027 unsigned long flags;
1028
1029 spin_lock_irqsave(&dev->power.lock, flags);
1030
1031 if (dev->power.disable_depth > 0)
1032 dev->power.disable_depth--;
1033 else
1034 dev_warn(dev, "Unbalanced %s!\n", __func__);
1035
1036 spin_unlock_irqrestore(&dev->power.lock, flags);
1037}
1038EXPORT_SYMBOL_GPL(pm_runtime_enable);
1039
1040/**
1041 * pm_runtime_forbid - Block runtime PM of a device.
1042 * @dev: Device to handle.
1043 *
1044 * Increase the device's usage count and clear its power.runtime_auto flag,
1045 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1046 * for it.
1047 */
1048void pm_runtime_forbid(struct device *dev)
1049{
1050 spin_lock_irq(&dev->power.lock);
1051 if (!dev->power.runtime_auto)
1052 goto out;
1053
1054 dev->power.runtime_auto = false;
1055 atomic_inc(&dev->power.usage_count);
1056 rpm_resume(dev, 0);
1057
1058 out:
1059 spin_unlock_irq(&dev->power.lock);
1060}
1061EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1062
1063/**
1064 * pm_runtime_allow - Unblock runtime PM of a device.
1065 * @dev: Device to handle.
1066 *
1067 * Decrease the device's usage count and set its power.runtime_auto flag.
1068 */
1069void pm_runtime_allow(struct device *dev)
1070{
1071 spin_lock_irq(&dev->power.lock);
1072 if (dev->power.runtime_auto)
1073 goto out;
1074
1075 dev->power.runtime_auto = true;
1076 if (atomic_dec_and_test(&dev->power.usage_count))
1077 rpm_idle(dev, RPM_AUTO);
1078
1079 out:
1080 spin_unlock_irq(&dev->power.lock);
1081}
1082EXPORT_SYMBOL_GPL(pm_runtime_allow);
1083
1084/**
1085 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1086 * @dev: Device to handle.
1087 *
1088 * Set the power.no_callbacks flag, which tells the PM core that this
1089 * device is power-managed through its parent and has no runtime PM
1090 * callbacks of its own. The runtime sysfs attributes will be removed.
1091 */
1092void pm_runtime_no_callbacks(struct device *dev)
1093{
1094 spin_lock_irq(&dev->power.lock);
1095 dev->power.no_callbacks = 1;
1096 spin_unlock_irq(&dev->power.lock);
1097 if (device_is_registered(dev))
1098 rpm_sysfs_remove(dev);
1099}
1100EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1101
1102/**
1103 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1104 * @dev: Device to handle
1105 *
1106 * Set the power.irq_safe flag, which tells the PM core that the
1107 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1108 * always be invoked with the spinlock held and interrupts disabled. It also
1109 * causes the parent's usage counter to be permanently incremented, preventing
1110 * the parent from runtime suspending -- otherwise an irq-safe child might have
1111 * to wait for a non-irq-safe parent.
1112 */
1113void pm_runtime_irq_safe(struct device *dev)
1114{
1115 if (dev->parent)
1116 pm_runtime_get_sync(dev->parent);
1117 spin_lock_irq(&dev->power.lock);
1118 dev->power.irq_safe = 1;
1119 spin_unlock_irq(&dev->power.lock);
1120}
1121EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1122
1123/**
1124 * update_autosuspend - Handle a change to a device's autosuspend settings.
1125 * @dev: Device to handle.
1126 * @old_delay: The former autosuspend_delay value.
1127 * @old_use: The former use_autosuspend value.
1128 *
1129 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1130 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1131 *
1132 * This function must be called under dev->power.lock with interrupts disabled.
1133 */
1134static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1135{
1136 int delay = dev->power.autosuspend_delay;
1137
1138 /* Should runtime suspend be prevented now? */
1139 if (dev->power.use_autosuspend && delay < 0) {
1140
1141 /* If it used to be allowed then prevent it. */
1142 if (!old_use || old_delay >= 0) {
1143 atomic_inc(&dev->power.usage_count);
1144 rpm_resume(dev, 0);
1145 }
1146 }
1147
1148 /* Runtime suspend should be allowed now. */
1149 else {
1150
1151 /* If it used to be prevented then allow it. */
1152 if (old_use && old_delay < 0)
1153 atomic_dec(&dev->power.usage_count);
1154
1155 /* Maybe we can autosuspend now. */
1156 rpm_idle(dev, RPM_AUTO);
1157 }
1158}
1159
1160/**
1161 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1162 * @dev: Device to handle.
1163 * @delay: Value of the new delay in milliseconds.
1164 *
1165 * Set the device's power.autosuspend_delay value. If it changes to negative
1166 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1167 * changes the other way, allow runtime suspends.
1168 */
1169void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1170{
1171 int old_delay, old_use;
1172
1173 spin_lock_irq(&dev->power.lock);
1174 old_delay = dev->power.autosuspend_delay;
1175 old_use = dev->power.use_autosuspend;
1176 dev->power.autosuspend_delay = delay;
1177 update_autosuspend(dev, old_delay, old_use);
1178 spin_unlock_irq(&dev->power.lock);
1179}
1180EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1181
1182/**
1183 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1184 * @dev: Device to handle.
1185 * @use: New value for use_autosuspend.
1186 *
1187 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1188 * suspends as needed.
1189 */
1190void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1191{
1192 int old_delay, old_use;
1193
1194 spin_lock_irq(&dev->power.lock);
1195 old_delay = dev->power.autosuspend_delay;
1196 old_use = dev->power.use_autosuspend;
1197 dev->power.use_autosuspend = use;
1198 update_autosuspend(dev, old_delay, old_use);
1199 spin_unlock_irq(&dev->power.lock);
1200}
1201EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1202
1203/**
1204 * pm_runtime_init - Initialize runtime PM fields in given device object.
1205 * @dev: Device object to initialize.
1206 */
1207void pm_runtime_init(struct device *dev)
1208{
1209 dev->power.runtime_status = RPM_SUSPENDED;
1210 dev->power.idle_notification = false;
1211
1212 dev->power.disable_depth = 1;
1213 atomic_set(&dev->power.usage_count, 0);
1214
1215 dev->power.runtime_error = 0;
1216
1217 atomic_set(&dev->power.child_count, 0);
1218 pm_suspend_ignore_children(dev, false);
1219 dev->power.runtime_auto = true;
1220
1221 dev->power.request_pending = false;
1222 dev->power.request = RPM_REQ_NONE;
1223 dev->power.deferred_resume = false;
1224 dev->power.accounting_timestamp = jiffies;
1225 INIT_WORK(&dev->power.work, pm_runtime_work);
1226
1227 dev->power.timer_expires = 0;
1228 setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1229 (unsigned long)dev);
1230
1231 init_waitqueue_head(&dev->power.wait_queue);
1232}
1233
1234/**
1235 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1236 * @dev: Device object being removed from device hierarchy.
1237 */
1238void pm_runtime_remove(struct device *dev)
1239{
1240 __pm_runtime_disable(dev, false);
1241
1242 /* Change the status back to 'suspended' to match the initial status. */
1243 if (dev->power.runtime_status == RPM_ACTIVE)
1244 pm_runtime_set_suspended(dev);
1245 if (dev->power.irq_safe && dev->parent)
1246 pm_runtime_put_sync(dev->parent);
1247}
1/*
2 * drivers/base/power/runtime.c - Helper functions for device runtime PM
3 *
4 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
6 *
7 * This file is released under the GPLv2.
8 */
9
10#include <linux/sched/mm.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 */
65void update_pm_runtime_accounting(struct device *dev)
66{
67 unsigned long now = jiffies;
68 unsigned long delta;
69
70 delta = now - dev->power.accounting_timestamp;
71
72 dev->power.accounting_timestamp = now;
73
74 if (dev->power.disable_depth > 0)
75 return;
76
77 if (dev->power.runtime_status == RPM_SUSPENDED)
78 dev->power.suspended_jiffies += delta;
79 else
80 dev->power.active_jiffies += delta;
81}
82
83static void __update_runtime_status(struct device *dev, enum rpm_status status)
84{
85 update_pm_runtime_accounting(dev);
86 dev->power.runtime_status = status;
87}
88
89/**
90 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
91 * @dev: Device to handle.
92 */
93static void pm_runtime_deactivate_timer(struct device *dev)
94{
95 if (dev->power.timer_expires > 0) {
96 del_timer(&dev->power.suspend_timer);
97 dev->power.timer_expires = 0;
98 }
99}
100
101/**
102 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
103 * @dev: Device to handle.
104 */
105static void pm_runtime_cancel_pending(struct device *dev)
106{
107 pm_runtime_deactivate_timer(dev);
108 /*
109 * In case there's a request pending, make sure its work function will
110 * return without doing anything.
111 */
112 dev->power.request = RPM_REQ_NONE;
113}
114
115/*
116 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
117 * @dev: Device to handle.
118 *
119 * Compute the autosuspend-delay expiration time based on the device's
120 * power.last_busy time. If the delay has already expired or is disabled
121 * (negative) or the power.use_autosuspend flag isn't set, return 0.
122 * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
123 *
124 * This function may be called either with or without dev->power.lock held.
125 * Either way it can be racy, since power.last_busy may be updated at any time.
126 */
127unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
128{
129 int autosuspend_delay;
130 long elapsed;
131 unsigned long last_busy;
132 unsigned long expires = 0;
133
134 if (!dev->power.use_autosuspend)
135 goto out;
136
137 autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
138 if (autosuspend_delay < 0)
139 goto out;
140
141 last_busy = READ_ONCE(dev->power.last_busy);
142 elapsed = jiffies - last_busy;
143 if (elapsed < 0)
144 goto out; /* jiffies has wrapped around. */
145
146 /*
147 * If the autosuspend_delay is >= 1 second, align the timer by rounding
148 * up to the nearest second.
149 */
150 expires = last_busy + msecs_to_jiffies(autosuspend_delay);
151 if (autosuspend_delay >= 1000)
152 expires = round_jiffies(expires);
153 expires += !expires;
154 if (elapsed >= expires - last_busy)
155 expires = 0; /* Already expired. */
156
157 out:
158 return expires;
159}
160EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
161
162static int dev_memalloc_noio(struct device *dev, void *data)
163{
164 return dev->power.memalloc_noio;
165}
166
167/*
168 * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
169 * @dev: Device to handle.
170 * @enable: True for setting the flag and False for clearing the flag.
171 *
172 * Set the flag for all devices in the path from the device to the
173 * root device in the device tree if @enable is true, otherwise clear
174 * the flag for devices in the path whose siblings don't set the flag.
175 *
176 * The function should only be called by block device, or network
177 * device driver for solving the deadlock problem during runtime
178 * resume/suspend:
179 *
180 * If memory allocation with GFP_KERNEL is called inside runtime
181 * resume/suspend callback of any one of its ancestors(or the
182 * block device itself), the deadlock may be triggered inside the
183 * memory allocation since it might not complete until the block
184 * device becomes active and the involed page I/O finishes. The
185 * situation is pointed out first by Alan Stern. Network device
186 * are involved in iSCSI kind of situation.
187 *
188 * The lock of dev_hotplug_mutex is held in the function for handling
189 * hotplug race because pm_runtime_set_memalloc_noio() may be called
190 * in async probe().
191 *
192 * The function should be called between device_add() and device_del()
193 * on the affected device(block/network device).
194 */
195void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
196{
197 static DEFINE_MUTEX(dev_hotplug_mutex);
198
199 mutex_lock(&dev_hotplug_mutex);
200 for (;;) {
201 bool enabled;
202
203 /* hold power lock since bitfield is not SMP-safe. */
204 spin_lock_irq(&dev->power.lock);
205 enabled = dev->power.memalloc_noio;
206 dev->power.memalloc_noio = enable;
207 spin_unlock_irq(&dev->power.lock);
208
209 /*
210 * not need to enable ancestors any more if the device
211 * has been enabled.
212 */
213 if (enabled && enable)
214 break;
215
216 dev = dev->parent;
217
218 /*
219 * clear flag of the parent device only if all the
220 * children don't set the flag because ancestor's
221 * flag was set by any one of the descendants.
222 */
223 if (!dev || (!enable &&
224 device_for_each_child(dev, NULL,
225 dev_memalloc_noio)))
226 break;
227 }
228 mutex_unlock(&dev_hotplug_mutex);
229}
230EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
231
232/**
233 * rpm_check_suspend_allowed - Test whether a device may be suspended.
234 * @dev: Device to test.
235 */
236static int rpm_check_suspend_allowed(struct device *dev)
237{
238 int retval = 0;
239
240 if (dev->power.runtime_error)
241 retval = -EINVAL;
242 else if (dev->power.disable_depth > 0)
243 retval = -EACCES;
244 else if (atomic_read(&dev->power.usage_count) > 0)
245 retval = -EAGAIN;
246 else if (!dev->power.ignore_children &&
247 atomic_read(&dev->power.child_count))
248 retval = -EBUSY;
249
250 /* Pending resume requests take precedence over suspends. */
251 else if ((dev->power.deferred_resume
252 && dev->power.runtime_status == RPM_SUSPENDING)
253 || (dev->power.request_pending
254 && dev->power.request == RPM_REQ_RESUME))
255 retval = -EAGAIN;
256 else if (__dev_pm_qos_read_value(dev) == 0)
257 retval = -EPERM;
258 else if (dev->power.runtime_status == RPM_SUSPENDED)
259 retval = 1;
260
261 return retval;
262}
263
264static int rpm_get_suppliers(struct device *dev)
265{
266 struct device_link *link;
267
268 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
269 int retval;
270
271 if (!(link->flags & DL_FLAG_PM_RUNTIME))
272 continue;
273
274 if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND ||
275 link->rpm_active)
276 continue;
277
278 retval = pm_runtime_get_sync(link->supplier);
279 /* Ignore suppliers with disabled runtime PM. */
280 if (retval < 0 && retval != -EACCES) {
281 pm_runtime_put_noidle(link->supplier);
282 return retval;
283 }
284 link->rpm_active = true;
285 }
286 return 0;
287}
288
289static void rpm_put_suppliers(struct device *dev)
290{
291 struct device_link *link;
292
293 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
294 if (link->rpm_active &&
295 READ_ONCE(link->status) != DL_STATE_SUPPLIER_UNBIND) {
296 pm_runtime_put(link->supplier);
297 link->rpm_active = false;
298 }
299}
300
301/**
302 * __rpm_callback - Run a given runtime PM callback for a given device.
303 * @cb: Runtime PM callback to run.
304 * @dev: Device to run the callback for.
305 */
306static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
307 __releases(&dev->power.lock) __acquires(&dev->power.lock)
308{
309 int retval, idx;
310 bool use_links = dev->power.links_count > 0;
311
312 if (dev->power.irq_safe) {
313 spin_unlock(&dev->power.lock);
314 } else {
315 spin_unlock_irq(&dev->power.lock);
316
317 /*
318 * Resume suppliers if necessary.
319 *
320 * The device's runtime PM status cannot change until this
321 * routine returns, so it is safe to read the status outside of
322 * the lock.
323 */
324 if (use_links && dev->power.runtime_status == RPM_RESUMING) {
325 idx = device_links_read_lock();
326
327 retval = rpm_get_suppliers(dev);
328 if (retval)
329 goto fail;
330
331 device_links_read_unlock(idx);
332 }
333 }
334
335 retval = cb(dev);
336
337 if (dev->power.irq_safe) {
338 spin_lock(&dev->power.lock);
339 } else {
340 /*
341 * If the device is suspending and the callback has returned
342 * success, drop the usage counters of the suppliers that have
343 * been reference counted on its resume.
344 *
345 * Do that if resume fails too.
346 */
347 if (use_links
348 && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
349 || (dev->power.runtime_status == RPM_RESUMING && retval))) {
350 idx = device_links_read_lock();
351
352 fail:
353 rpm_put_suppliers(dev);
354
355 device_links_read_unlock(idx);
356 }
357
358 spin_lock_irq(&dev->power.lock);
359 }
360
361 return retval;
362}
363
364/**
365 * rpm_idle - Notify device bus type if the device can be suspended.
366 * @dev: Device to notify the bus type about.
367 * @rpmflags: Flag bits.
368 *
369 * Check if the device's runtime PM status allows it to be suspended. If
370 * another idle notification has been started earlier, return immediately. If
371 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
372 * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
373 * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
374 *
375 * This function must be called under dev->power.lock with interrupts disabled.
376 */
377static int rpm_idle(struct device *dev, int rpmflags)
378{
379 int (*callback)(struct device *);
380 int retval;
381
382 trace_rpm_idle_rcuidle(dev, rpmflags);
383 retval = rpm_check_suspend_allowed(dev);
384 if (retval < 0)
385 ; /* Conditions are wrong. */
386
387 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
388 else if (dev->power.runtime_status != RPM_ACTIVE)
389 retval = -EAGAIN;
390
391 /*
392 * Any pending request other than an idle notification takes
393 * precedence over us, except that the timer may be running.
394 */
395 else if (dev->power.request_pending &&
396 dev->power.request > RPM_REQ_IDLE)
397 retval = -EAGAIN;
398
399 /* Act as though RPM_NOWAIT is always set. */
400 else if (dev->power.idle_notification)
401 retval = -EINPROGRESS;
402 if (retval)
403 goto out;
404
405 /* Pending requests need to be canceled. */
406 dev->power.request = RPM_REQ_NONE;
407
408 if (dev->power.no_callbacks)
409 goto out;
410
411 /* Carry out an asynchronous or a synchronous idle notification. */
412 if (rpmflags & RPM_ASYNC) {
413 dev->power.request = RPM_REQ_IDLE;
414 if (!dev->power.request_pending) {
415 dev->power.request_pending = true;
416 queue_work(pm_wq, &dev->power.work);
417 }
418 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
419 return 0;
420 }
421
422 dev->power.idle_notification = true;
423
424 callback = RPM_GET_CALLBACK(dev, runtime_idle);
425
426 if (callback)
427 retval = __rpm_callback(callback, dev);
428
429 dev->power.idle_notification = false;
430 wake_up_all(&dev->power.wait_queue);
431
432 out:
433 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
434 return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
435}
436
437/**
438 * rpm_callback - Run a given runtime PM callback for a given device.
439 * @cb: Runtime PM callback to run.
440 * @dev: Device to run the callback for.
441 */
442static int rpm_callback(int (*cb)(struct device *), struct device *dev)
443{
444 int retval;
445
446 if (!cb)
447 return -ENOSYS;
448
449 if (dev->power.memalloc_noio) {
450 unsigned int noio_flag;
451
452 /*
453 * Deadlock might be caused if memory allocation with
454 * GFP_KERNEL happens inside runtime_suspend and
455 * runtime_resume callbacks of one block device's
456 * ancestor or the block device itself. Network
457 * device might be thought as part of iSCSI block
458 * device, so network device and its ancestor should
459 * be marked as memalloc_noio too.
460 */
461 noio_flag = memalloc_noio_save();
462 retval = __rpm_callback(cb, dev);
463 memalloc_noio_restore(noio_flag);
464 } else {
465 retval = __rpm_callback(cb, dev);
466 }
467
468 dev->power.runtime_error = retval;
469 return retval != -EACCES ? retval : -EIO;
470}
471
472/**
473 * rpm_suspend - Carry out runtime suspend of given device.
474 * @dev: Device to suspend.
475 * @rpmflags: Flag bits.
476 *
477 * Check if the device's runtime PM status allows it to be suspended.
478 * Cancel a pending idle notification, autosuspend or suspend. If
479 * another suspend has been started earlier, either return immediately
480 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
481 * flags. If the RPM_ASYNC flag is set then queue a suspend request;
482 * otherwise run the ->runtime_suspend() callback directly. When
483 * ->runtime_suspend succeeded, if a deferred resume was requested while
484 * the callback was running then carry it out, otherwise send an idle
485 * notification for its parent (if the suspend succeeded and both
486 * ignore_children of parent->power and irq_safe of dev->power are not set).
487 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
488 * flag is set and the next autosuspend-delay expiration time is in the
489 * future, schedule another autosuspend attempt.
490 *
491 * This function must be called under dev->power.lock with interrupts disabled.
492 */
493static int rpm_suspend(struct device *dev, int rpmflags)
494 __releases(&dev->power.lock) __acquires(&dev->power.lock)
495{
496 int (*callback)(struct device *);
497 struct device *parent = NULL;
498 int retval;
499
500 trace_rpm_suspend_rcuidle(dev, rpmflags);
501
502 repeat:
503 retval = rpm_check_suspend_allowed(dev);
504
505 if (retval < 0)
506 ; /* Conditions are wrong. */
507
508 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
509 else if (dev->power.runtime_status == RPM_RESUMING &&
510 !(rpmflags & RPM_ASYNC))
511 retval = -EAGAIN;
512 if (retval)
513 goto out;
514
515 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
516 if ((rpmflags & RPM_AUTO)
517 && dev->power.runtime_status != RPM_SUSPENDING) {
518 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
519
520 if (expires != 0) {
521 /* Pending requests need to be canceled. */
522 dev->power.request = RPM_REQ_NONE;
523
524 /*
525 * Optimization: If the timer is already running and is
526 * set to expire at or before the autosuspend delay,
527 * avoid the overhead of resetting it. Just let it
528 * expire; pm_suspend_timer_fn() will take care of the
529 * rest.
530 */
531 if (!(dev->power.timer_expires && time_before_eq(
532 dev->power.timer_expires, expires))) {
533 dev->power.timer_expires = expires;
534 mod_timer(&dev->power.suspend_timer, expires);
535 }
536 dev->power.timer_autosuspends = 1;
537 goto out;
538 }
539 }
540
541 /* Other scheduled or pending requests need to be canceled. */
542 pm_runtime_cancel_pending(dev);
543
544 if (dev->power.runtime_status == RPM_SUSPENDING) {
545 DEFINE_WAIT(wait);
546
547 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
548 retval = -EINPROGRESS;
549 goto out;
550 }
551
552 if (dev->power.irq_safe) {
553 spin_unlock(&dev->power.lock);
554
555 cpu_relax();
556
557 spin_lock(&dev->power.lock);
558 goto repeat;
559 }
560
561 /* Wait for the other suspend running in parallel with us. */
562 for (;;) {
563 prepare_to_wait(&dev->power.wait_queue, &wait,
564 TASK_UNINTERRUPTIBLE);
565 if (dev->power.runtime_status != RPM_SUSPENDING)
566 break;
567
568 spin_unlock_irq(&dev->power.lock);
569
570 schedule();
571
572 spin_lock_irq(&dev->power.lock);
573 }
574 finish_wait(&dev->power.wait_queue, &wait);
575 goto repeat;
576 }
577
578 if (dev->power.no_callbacks)
579 goto no_callback; /* Assume success. */
580
581 /* Carry out an asynchronous or a synchronous suspend. */
582 if (rpmflags & RPM_ASYNC) {
583 dev->power.request = (rpmflags & RPM_AUTO) ?
584 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
585 if (!dev->power.request_pending) {
586 dev->power.request_pending = true;
587 queue_work(pm_wq, &dev->power.work);
588 }
589 goto out;
590 }
591
592 __update_runtime_status(dev, RPM_SUSPENDING);
593
594 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
595
596 dev_pm_enable_wake_irq_check(dev, true);
597 retval = rpm_callback(callback, dev);
598 if (retval)
599 goto fail;
600
601 no_callback:
602 __update_runtime_status(dev, RPM_SUSPENDED);
603 pm_runtime_deactivate_timer(dev);
604
605 if (dev->parent) {
606 parent = dev->parent;
607 atomic_add_unless(&parent->power.child_count, -1, 0);
608 }
609 wake_up_all(&dev->power.wait_queue);
610
611 if (dev->power.deferred_resume) {
612 dev->power.deferred_resume = false;
613 rpm_resume(dev, 0);
614 retval = -EAGAIN;
615 goto out;
616 }
617
618 /* Maybe the parent is now able to suspend. */
619 if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
620 spin_unlock(&dev->power.lock);
621
622 spin_lock(&parent->power.lock);
623 rpm_idle(parent, RPM_ASYNC);
624 spin_unlock(&parent->power.lock);
625
626 spin_lock(&dev->power.lock);
627 }
628
629 out:
630 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
631
632 return retval;
633
634 fail:
635 dev_pm_disable_wake_irq_check(dev);
636 __update_runtime_status(dev, RPM_ACTIVE);
637 dev->power.deferred_resume = false;
638 wake_up_all(&dev->power.wait_queue);
639
640 if (retval == -EAGAIN || retval == -EBUSY) {
641 dev->power.runtime_error = 0;
642
643 /*
644 * If the callback routine failed an autosuspend, and
645 * if the last_busy time has been updated so that there
646 * is a new autosuspend expiration time, automatically
647 * reschedule another autosuspend.
648 */
649 if ((rpmflags & RPM_AUTO) &&
650 pm_runtime_autosuspend_expiration(dev) != 0)
651 goto repeat;
652 } else {
653 pm_runtime_cancel_pending(dev);
654 }
655 goto out;
656}
657
658/**
659 * rpm_resume - Carry out runtime resume of given device.
660 * @dev: Device to resume.
661 * @rpmflags: Flag bits.
662 *
663 * Check if the device's runtime PM status allows it to be resumed. Cancel
664 * any scheduled or pending requests. If another resume has been started
665 * earlier, either return immediately or wait for it to finish, depending on the
666 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
667 * parallel with this function, either tell the other process to resume after
668 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
669 * flag is set then queue a resume request; otherwise run the
670 * ->runtime_resume() callback directly. Queue an idle notification for the
671 * device if the resume succeeded.
672 *
673 * This function must be called under dev->power.lock with interrupts disabled.
674 */
675static int rpm_resume(struct device *dev, int rpmflags)
676 __releases(&dev->power.lock) __acquires(&dev->power.lock)
677{
678 int (*callback)(struct device *);
679 struct device *parent = NULL;
680 int retval = 0;
681
682 trace_rpm_resume_rcuidle(dev, rpmflags);
683
684 repeat:
685 if (dev->power.runtime_error)
686 retval = -EINVAL;
687 else if (dev->power.disable_depth == 1 && dev->power.is_suspended
688 && dev->power.runtime_status == RPM_ACTIVE)
689 retval = 1;
690 else if (dev->power.disable_depth > 0)
691 retval = -EACCES;
692 if (retval)
693 goto out;
694
695 /*
696 * Other scheduled or pending requests need to be canceled. Small
697 * optimization: If an autosuspend timer is running, leave it running
698 * rather than cancelling it now only to restart it again in the near
699 * future.
700 */
701 dev->power.request = RPM_REQ_NONE;
702 if (!dev->power.timer_autosuspends)
703 pm_runtime_deactivate_timer(dev);
704
705 if (dev->power.runtime_status == RPM_ACTIVE) {
706 retval = 1;
707 goto out;
708 }
709
710 if (dev->power.runtime_status == RPM_RESUMING
711 || dev->power.runtime_status == RPM_SUSPENDING) {
712 DEFINE_WAIT(wait);
713
714 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
715 if (dev->power.runtime_status == RPM_SUSPENDING)
716 dev->power.deferred_resume = true;
717 else
718 retval = -EINPROGRESS;
719 goto out;
720 }
721
722 if (dev->power.irq_safe) {
723 spin_unlock(&dev->power.lock);
724
725 cpu_relax();
726
727 spin_lock(&dev->power.lock);
728 goto repeat;
729 }
730
731 /* Wait for the operation carried out in parallel with us. */
732 for (;;) {
733 prepare_to_wait(&dev->power.wait_queue, &wait,
734 TASK_UNINTERRUPTIBLE);
735 if (dev->power.runtime_status != RPM_RESUMING
736 && dev->power.runtime_status != RPM_SUSPENDING)
737 break;
738
739 spin_unlock_irq(&dev->power.lock);
740
741 schedule();
742
743 spin_lock_irq(&dev->power.lock);
744 }
745 finish_wait(&dev->power.wait_queue, &wait);
746 goto repeat;
747 }
748
749 /*
750 * See if we can skip waking up the parent. This is safe only if
751 * power.no_callbacks is set, because otherwise we don't know whether
752 * the resume will actually succeed.
753 */
754 if (dev->power.no_callbacks && !parent && dev->parent) {
755 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
756 if (dev->parent->power.disable_depth > 0
757 || dev->parent->power.ignore_children
758 || dev->parent->power.runtime_status == RPM_ACTIVE) {
759 atomic_inc(&dev->parent->power.child_count);
760 spin_unlock(&dev->parent->power.lock);
761 retval = 1;
762 goto no_callback; /* Assume success. */
763 }
764 spin_unlock(&dev->parent->power.lock);
765 }
766
767 /* Carry out an asynchronous or a synchronous resume. */
768 if (rpmflags & RPM_ASYNC) {
769 dev->power.request = RPM_REQ_RESUME;
770 if (!dev->power.request_pending) {
771 dev->power.request_pending = true;
772 queue_work(pm_wq, &dev->power.work);
773 }
774 retval = 0;
775 goto out;
776 }
777
778 if (!parent && dev->parent) {
779 /*
780 * Increment the parent's usage counter and resume it if
781 * necessary. Not needed if dev is irq-safe; then the
782 * parent is permanently resumed.
783 */
784 parent = dev->parent;
785 if (dev->power.irq_safe)
786 goto skip_parent;
787 spin_unlock(&dev->power.lock);
788
789 pm_runtime_get_noresume(parent);
790
791 spin_lock(&parent->power.lock);
792 /*
793 * Resume the parent if it has runtime PM enabled and not been
794 * set to ignore its children.
795 */
796 if (!parent->power.disable_depth
797 && !parent->power.ignore_children) {
798 rpm_resume(parent, 0);
799 if (parent->power.runtime_status != RPM_ACTIVE)
800 retval = -EBUSY;
801 }
802 spin_unlock(&parent->power.lock);
803
804 spin_lock(&dev->power.lock);
805 if (retval)
806 goto out;
807 goto repeat;
808 }
809 skip_parent:
810
811 if (dev->power.no_callbacks)
812 goto no_callback; /* Assume success. */
813
814 __update_runtime_status(dev, RPM_RESUMING);
815
816 callback = RPM_GET_CALLBACK(dev, runtime_resume);
817
818 dev_pm_disable_wake_irq_check(dev);
819 retval = rpm_callback(callback, dev);
820 if (retval) {
821 __update_runtime_status(dev, RPM_SUSPENDED);
822 pm_runtime_cancel_pending(dev);
823 dev_pm_enable_wake_irq_check(dev, false);
824 } else {
825 no_callback:
826 __update_runtime_status(dev, RPM_ACTIVE);
827 pm_runtime_mark_last_busy(dev);
828 if (parent)
829 atomic_inc(&parent->power.child_count);
830 }
831 wake_up_all(&dev->power.wait_queue);
832
833 if (retval >= 0)
834 rpm_idle(dev, RPM_ASYNC);
835
836 out:
837 if (parent && !dev->power.irq_safe) {
838 spin_unlock_irq(&dev->power.lock);
839
840 pm_runtime_put(parent);
841
842 spin_lock_irq(&dev->power.lock);
843 }
844
845 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
846
847 return retval;
848}
849
850/**
851 * pm_runtime_work - Universal runtime PM work function.
852 * @work: Work structure used for scheduling the execution of this function.
853 *
854 * Use @work to get the device object the work is to be done for, determine what
855 * is to be done and execute the appropriate runtime PM function.
856 */
857static void pm_runtime_work(struct work_struct *work)
858{
859 struct device *dev = container_of(work, struct device, power.work);
860 enum rpm_request req;
861
862 spin_lock_irq(&dev->power.lock);
863
864 if (!dev->power.request_pending)
865 goto out;
866
867 req = dev->power.request;
868 dev->power.request = RPM_REQ_NONE;
869 dev->power.request_pending = false;
870
871 switch (req) {
872 case RPM_REQ_NONE:
873 break;
874 case RPM_REQ_IDLE:
875 rpm_idle(dev, RPM_NOWAIT);
876 break;
877 case RPM_REQ_SUSPEND:
878 rpm_suspend(dev, RPM_NOWAIT);
879 break;
880 case RPM_REQ_AUTOSUSPEND:
881 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
882 break;
883 case RPM_REQ_RESUME:
884 rpm_resume(dev, RPM_NOWAIT);
885 break;
886 }
887
888 out:
889 spin_unlock_irq(&dev->power.lock);
890}
891
892/**
893 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
894 * @data: Device pointer passed by pm_schedule_suspend().
895 *
896 * Check if the time is right and queue a suspend request.
897 */
898static void pm_suspend_timer_fn(struct timer_list *t)
899{
900 struct device *dev = from_timer(dev, t, power.suspend_timer);
901 unsigned long flags;
902 unsigned long expires;
903
904 spin_lock_irqsave(&dev->power.lock, flags);
905
906 expires = dev->power.timer_expires;
907 /* If 'expire' is after 'jiffies' we've been called too early. */
908 if (expires > 0 && !time_after(expires, jiffies)) {
909 dev->power.timer_expires = 0;
910 rpm_suspend(dev, dev->power.timer_autosuspends ?
911 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
912 }
913
914 spin_unlock_irqrestore(&dev->power.lock, flags);
915}
916
917/**
918 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
919 * @dev: Device to suspend.
920 * @delay: Time to wait before submitting a suspend request, in milliseconds.
921 */
922int pm_schedule_suspend(struct device *dev, unsigned int delay)
923{
924 unsigned long flags;
925 int retval;
926
927 spin_lock_irqsave(&dev->power.lock, flags);
928
929 if (!delay) {
930 retval = rpm_suspend(dev, RPM_ASYNC);
931 goto out;
932 }
933
934 retval = rpm_check_suspend_allowed(dev);
935 if (retval)
936 goto out;
937
938 /* Other scheduled or pending requests need to be canceled. */
939 pm_runtime_cancel_pending(dev);
940
941 dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
942 dev->power.timer_expires += !dev->power.timer_expires;
943 dev->power.timer_autosuspends = 0;
944 mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
945
946 out:
947 spin_unlock_irqrestore(&dev->power.lock, flags);
948
949 return retval;
950}
951EXPORT_SYMBOL_GPL(pm_schedule_suspend);
952
953/**
954 * __pm_runtime_idle - Entry point for runtime idle operations.
955 * @dev: Device to send idle notification for.
956 * @rpmflags: Flag bits.
957 *
958 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
959 * return immediately if it is larger than zero. Then carry out an idle
960 * notification, either synchronous or asynchronous.
961 *
962 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
963 * or if pm_runtime_irq_safe() has been called.
964 */
965int __pm_runtime_idle(struct device *dev, int rpmflags)
966{
967 unsigned long flags;
968 int retval;
969
970 if (rpmflags & RPM_GET_PUT) {
971 if (!atomic_dec_and_test(&dev->power.usage_count))
972 return 0;
973 }
974
975 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
976
977 spin_lock_irqsave(&dev->power.lock, flags);
978 retval = rpm_idle(dev, rpmflags);
979 spin_unlock_irqrestore(&dev->power.lock, flags);
980
981 return retval;
982}
983EXPORT_SYMBOL_GPL(__pm_runtime_idle);
984
985/**
986 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
987 * @dev: Device to suspend.
988 * @rpmflags: Flag bits.
989 *
990 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
991 * return immediately if it is larger than zero. Then carry out a suspend,
992 * either synchronous or asynchronous.
993 *
994 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
995 * or if pm_runtime_irq_safe() has been called.
996 */
997int __pm_runtime_suspend(struct device *dev, int rpmflags)
998{
999 unsigned long flags;
1000 int retval;
1001
1002 if (rpmflags & RPM_GET_PUT) {
1003 if (!atomic_dec_and_test(&dev->power.usage_count))
1004 return 0;
1005 }
1006
1007 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1008
1009 spin_lock_irqsave(&dev->power.lock, flags);
1010 retval = rpm_suspend(dev, rpmflags);
1011 spin_unlock_irqrestore(&dev->power.lock, flags);
1012
1013 return retval;
1014}
1015EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
1016
1017/**
1018 * __pm_runtime_resume - Entry point for runtime resume operations.
1019 * @dev: Device to resume.
1020 * @rpmflags: Flag bits.
1021 *
1022 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
1023 * carry out a resume, either synchronous or asynchronous.
1024 *
1025 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1026 * or if pm_runtime_irq_safe() has been called.
1027 */
1028int __pm_runtime_resume(struct device *dev, int rpmflags)
1029{
1030 unsigned long flags;
1031 int retval;
1032
1033 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
1034 dev->power.runtime_status != RPM_ACTIVE);
1035
1036 if (rpmflags & RPM_GET_PUT)
1037 atomic_inc(&dev->power.usage_count);
1038
1039 spin_lock_irqsave(&dev->power.lock, flags);
1040 retval = rpm_resume(dev, rpmflags);
1041 spin_unlock_irqrestore(&dev->power.lock, flags);
1042
1043 return retval;
1044}
1045EXPORT_SYMBOL_GPL(__pm_runtime_resume);
1046
1047/**
1048 * pm_runtime_get_if_in_use - Conditionally bump up the device's usage counter.
1049 * @dev: Device to handle.
1050 *
1051 * Return -EINVAL if runtime PM is disabled for the device.
1052 *
1053 * If that's not the case and if the device's runtime PM status is RPM_ACTIVE
1054 * and the runtime PM usage counter is nonzero, increment the counter and
1055 * return 1. Otherwise return 0 without changing the counter.
1056 */
1057int pm_runtime_get_if_in_use(struct device *dev)
1058{
1059 unsigned long flags;
1060 int retval;
1061
1062 spin_lock_irqsave(&dev->power.lock, flags);
1063 retval = dev->power.disable_depth > 0 ? -EINVAL :
1064 dev->power.runtime_status == RPM_ACTIVE
1065 && atomic_inc_not_zero(&dev->power.usage_count);
1066 spin_unlock_irqrestore(&dev->power.lock, flags);
1067 return retval;
1068}
1069EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
1070
1071/**
1072 * __pm_runtime_set_status - Set runtime PM status of a device.
1073 * @dev: Device to handle.
1074 * @status: New runtime PM status of the device.
1075 *
1076 * If runtime PM of the device is disabled or its power.runtime_error field is
1077 * different from zero, the status may be changed either to RPM_ACTIVE, or to
1078 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1079 * However, if the device has a parent and the parent is not active, and the
1080 * parent's power.ignore_children flag is unset, the device's status cannot be
1081 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1082 *
1083 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1084 * and the device parent's counter of unsuspended children is modified to
1085 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
1086 * notification request for the parent is submitted.
1087 */
1088int __pm_runtime_set_status(struct device *dev, unsigned int status)
1089{
1090 struct device *parent = dev->parent;
1091 unsigned long flags;
1092 bool notify_parent = false;
1093 int error = 0;
1094
1095 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1096 return -EINVAL;
1097
1098 spin_lock_irqsave(&dev->power.lock, flags);
1099
1100 if (!dev->power.runtime_error && !dev->power.disable_depth) {
1101 error = -EAGAIN;
1102 goto out;
1103 }
1104
1105 if (dev->power.runtime_status == status || !parent)
1106 goto out_set;
1107
1108 if (status == RPM_SUSPENDED) {
1109 atomic_add_unless(&parent->power.child_count, -1, 0);
1110 notify_parent = !parent->power.ignore_children;
1111 } else {
1112 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1113
1114 /*
1115 * It is invalid to put an active child under a parent that is
1116 * not active, has runtime PM enabled and the
1117 * 'power.ignore_children' flag unset.
1118 */
1119 if (!parent->power.disable_depth
1120 && !parent->power.ignore_children
1121 && parent->power.runtime_status != RPM_ACTIVE) {
1122 dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1123 dev_name(dev),
1124 dev_name(parent));
1125 error = -EBUSY;
1126 } else if (dev->power.runtime_status == RPM_SUSPENDED) {
1127 atomic_inc(&parent->power.child_count);
1128 }
1129
1130 spin_unlock(&parent->power.lock);
1131
1132 if (error)
1133 goto out;
1134 }
1135
1136 out_set:
1137 __update_runtime_status(dev, status);
1138 dev->power.runtime_error = 0;
1139 out:
1140 spin_unlock_irqrestore(&dev->power.lock, flags);
1141
1142 if (notify_parent)
1143 pm_request_idle(parent);
1144
1145 return error;
1146}
1147EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1148
1149/**
1150 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1151 * @dev: Device to handle.
1152 *
1153 * Flush all pending requests for the device from pm_wq and wait for all
1154 * runtime PM operations involving the device in progress to complete.
1155 *
1156 * Should be called under dev->power.lock with interrupts disabled.
1157 */
1158static void __pm_runtime_barrier(struct device *dev)
1159{
1160 pm_runtime_deactivate_timer(dev);
1161
1162 if (dev->power.request_pending) {
1163 dev->power.request = RPM_REQ_NONE;
1164 spin_unlock_irq(&dev->power.lock);
1165
1166 cancel_work_sync(&dev->power.work);
1167
1168 spin_lock_irq(&dev->power.lock);
1169 dev->power.request_pending = false;
1170 }
1171
1172 if (dev->power.runtime_status == RPM_SUSPENDING
1173 || dev->power.runtime_status == RPM_RESUMING
1174 || dev->power.idle_notification) {
1175 DEFINE_WAIT(wait);
1176
1177 /* Suspend, wake-up or idle notification in progress. */
1178 for (;;) {
1179 prepare_to_wait(&dev->power.wait_queue, &wait,
1180 TASK_UNINTERRUPTIBLE);
1181 if (dev->power.runtime_status != RPM_SUSPENDING
1182 && dev->power.runtime_status != RPM_RESUMING
1183 && !dev->power.idle_notification)
1184 break;
1185 spin_unlock_irq(&dev->power.lock);
1186
1187 schedule();
1188
1189 spin_lock_irq(&dev->power.lock);
1190 }
1191 finish_wait(&dev->power.wait_queue, &wait);
1192 }
1193}
1194
1195/**
1196 * pm_runtime_barrier - Flush pending requests and wait for completions.
1197 * @dev: Device to handle.
1198 *
1199 * Prevent the device from being suspended by incrementing its usage counter and
1200 * if there's a pending resume request for the device, wake the device up.
1201 * Next, make sure that all pending requests for the device have been flushed
1202 * from pm_wq and wait for all runtime PM operations involving the device in
1203 * progress to complete.
1204 *
1205 * Return value:
1206 * 1, if there was a resume request pending and the device had to be woken up,
1207 * 0, otherwise
1208 */
1209int pm_runtime_barrier(struct device *dev)
1210{
1211 int retval = 0;
1212
1213 pm_runtime_get_noresume(dev);
1214 spin_lock_irq(&dev->power.lock);
1215
1216 if (dev->power.request_pending
1217 && dev->power.request == RPM_REQ_RESUME) {
1218 rpm_resume(dev, 0);
1219 retval = 1;
1220 }
1221
1222 __pm_runtime_barrier(dev);
1223
1224 spin_unlock_irq(&dev->power.lock);
1225 pm_runtime_put_noidle(dev);
1226
1227 return retval;
1228}
1229EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1230
1231/**
1232 * __pm_runtime_disable - Disable runtime PM of a device.
1233 * @dev: Device to handle.
1234 * @check_resume: If set, check if there's a resume request for the device.
1235 *
1236 * Increment power.disable_depth for the device and if it was zero previously,
1237 * cancel all pending runtime PM requests for the device and wait for all
1238 * operations in progress to complete. The device can be either active or
1239 * suspended after its runtime PM has been disabled.
1240 *
1241 * If @check_resume is set and there's a resume request pending when
1242 * __pm_runtime_disable() is called and power.disable_depth is zero, the
1243 * function will wake up the device before disabling its runtime PM.
1244 */
1245void __pm_runtime_disable(struct device *dev, bool check_resume)
1246{
1247 spin_lock_irq(&dev->power.lock);
1248
1249 if (dev->power.disable_depth > 0) {
1250 dev->power.disable_depth++;
1251 goto out;
1252 }
1253
1254 /*
1255 * Wake up the device if there's a resume request pending, because that
1256 * means there probably is some I/O to process and disabling runtime PM
1257 * shouldn't prevent the device from processing the I/O.
1258 */
1259 if (check_resume && dev->power.request_pending
1260 && dev->power.request == RPM_REQ_RESUME) {
1261 /*
1262 * Prevent suspends and idle notifications from being carried
1263 * out after we have woken up the device.
1264 */
1265 pm_runtime_get_noresume(dev);
1266
1267 rpm_resume(dev, 0);
1268
1269 pm_runtime_put_noidle(dev);
1270 }
1271
1272 if (!dev->power.disable_depth++)
1273 __pm_runtime_barrier(dev);
1274
1275 out:
1276 spin_unlock_irq(&dev->power.lock);
1277}
1278EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1279
1280/**
1281 * pm_runtime_enable - Enable runtime PM of a device.
1282 * @dev: Device to handle.
1283 */
1284void pm_runtime_enable(struct device *dev)
1285{
1286 unsigned long flags;
1287
1288 spin_lock_irqsave(&dev->power.lock, flags);
1289
1290 if (dev->power.disable_depth > 0)
1291 dev->power.disable_depth--;
1292 else
1293 dev_warn(dev, "Unbalanced %s!\n", __func__);
1294
1295 WARN(!dev->power.disable_depth &&
1296 dev->power.runtime_status == RPM_SUSPENDED &&
1297 !dev->power.ignore_children &&
1298 atomic_read(&dev->power.child_count) > 0,
1299 "Enabling runtime PM for inactive device (%s) with active children\n",
1300 dev_name(dev));
1301
1302 spin_unlock_irqrestore(&dev->power.lock, flags);
1303}
1304EXPORT_SYMBOL_GPL(pm_runtime_enable);
1305
1306/**
1307 * pm_runtime_forbid - Block runtime PM of a device.
1308 * @dev: Device to handle.
1309 *
1310 * Increase the device's usage count and clear its power.runtime_auto flag,
1311 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1312 * for it.
1313 */
1314void pm_runtime_forbid(struct device *dev)
1315{
1316 spin_lock_irq(&dev->power.lock);
1317 if (!dev->power.runtime_auto)
1318 goto out;
1319
1320 dev->power.runtime_auto = false;
1321 atomic_inc(&dev->power.usage_count);
1322 rpm_resume(dev, 0);
1323
1324 out:
1325 spin_unlock_irq(&dev->power.lock);
1326}
1327EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1328
1329/**
1330 * pm_runtime_allow - Unblock runtime PM of a device.
1331 * @dev: Device to handle.
1332 *
1333 * Decrease the device's usage count and set its power.runtime_auto flag.
1334 */
1335void pm_runtime_allow(struct device *dev)
1336{
1337 spin_lock_irq(&dev->power.lock);
1338 if (dev->power.runtime_auto)
1339 goto out;
1340
1341 dev->power.runtime_auto = true;
1342 if (atomic_dec_and_test(&dev->power.usage_count))
1343 rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1344
1345 out:
1346 spin_unlock_irq(&dev->power.lock);
1347}
1348EXPORT_SYMBOL_GPL(pm_runtime_allow);
1349
1350/**
1351 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1352 * @dev: Device to handle.
1353 *
1354 * Set the power.no_callbacks flag, which tells the PM core that this
1355 * device is power-managed through its parent and has no runtime PM
1356 * callbacks of its own. The runtime sysfs attributes will be removed.
1357 */
1358void pm_runtime_no_callbacks(struct device *dev)
1359{
1360 spin_lock_irq(&dev->power.lock);
1361 dev->power.no_callbacks = 1;
1362 spin_unlock_irq(&dev->power.lock);
1363 if (device_is_registered(dev))
1364 rpm_sysfs_remove(dev);
1365}
1366EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1367
1368/**
1369 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1370 * @dev: Device to handle
1371 *
1372 * Set the power.irq_safe flag, which tells the PM core that the
1373 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1374 * always be invoked with the spinlock held and interrupts disabled. It also
1375 * causes the parent's usage counter to be permanently incremented, preventing
1376 * the parent from runtime suspending -- otherwise an irq-safe child might have
1377 * to wait for a non-irq-safe parent.
1378 */
1379void pm_runtime_irq_safe(struct device *dev)
1380{
1381 if (dev->parent)
1382 pm_runtime_get_sync(dev->parent);
1383 spin_lock_irq(&dev->power.lock);
1384 dev->power.irq_safe = 1;
1385 spin_unlock_irq(&dev->power.lock);
1386}
1387EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1388
1389/**
1390 * update_autosuspend - Handle a change to a device's autosuspend settings.
1391 * @dev: Device to handle.
1392 * @old_delay: The former autosuspend_delay value.
1393 * @old_use: The former use_autosuspend value.
1394 *
1395 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1396 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1397 *
1398 * This function must be called under dev->power.lock with interrupts disabled.
1399 */
1400static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1401{
1402 int delay = dev->power.autosuspend_delay;
1403
1404 /* Should runtime suspend be prevented now? */
1405 if (dev->power.use_autosuspend && delay < 0) {
1406
1407 /* If it used to be allowed then prevent it. */
1408 if (!old_use || old_delay >= 0) {
1409 atomic_inc(&dev->power.usage_count);
1410 rpm_resume(dev, 0);
1411 }
1412 }
1413
1414 /* Runtime suspend should be allowed now. */
1415 else {
1416
1417 /* If it used to be prevented then allow it. */
1418 if (old_use && old_delay < 0)
1419 atomic_dec(&dev->power.usage_count);
1420
1421 /* Maybe we can autosuspend now. */
1422 rpm_idle(dev, RPM_AUTO);
1423 }
1424}
1425
1426/**
1427 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1428 * @dev: Device to handle.
1429 * @delay: Value of the new delay in milliseconds.
1430 *
1431 * Set the device's power.autosuspend_delay value. If it changes to negative
1432 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1433 * changes the other way, allow runtime suspends.
1434 */
1435void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1436{
1437 int old_delay, old_use;
1438
1439 spin_lock_irq(&dev->power.lock);
1440 old_delay = dev->power.autosuspend_delay;
1441 old_use = dev->power.use_autosuspend;
1442 dev->power.autosuspend_delay = delay;
1443 update_autosuspend(dev, old_delay, old_use);
1444 spin_unlock_irq(&dev->power.lock);
1445}
1446EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1447
1448/**
1449 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1450 * @dev: Device to handle.
1451 * @use: New value for use_autosuspend.
1452 *
1453 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1454 * suspends as needed.
1455 */
1456void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1457{
1458 int old_delay, old_use;
1459
1460 spin_lock_irq(&dev->power.lock);
1461 old_delay = dev->power.autosuspend_delay;
1462 old_use = dev->power.use_autosuspend;
1463 dev->power.use_autosuspend = use;
1464 update_autosuspend(dev, old_delay, old_use);
1465 spin_unlock_irq(&dev->power.lock);
1466}
1467EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1468
1469/**
1470 * pm_runtime_init - Initialize runtime PM fields in given device object.
1471 * @dev: Device object to initialize.
1472 */
1473void pm_runtime_init(struct device *dev)
1474{
1475 dev->power.runtime_status = RPM_SUSPENDED;
1476 dev->power.idle_notification = false;
1477
1478 dev->power.disable_depth = 1;
1479 atomic_set(&dev->power.usage_count, 0);
1480
1481 dev->power.runtime_error = 0;
1482
1483 atomic_set(&dev->power.child_count, 0);
1484 pm_suspend_ignore_children(dev, false);
1485 dev->power.runtime_auto = true;
1486
1487 dev->power.request_pending = false;
1488 dev->power.request = RPM_REQ_NONE;
1489 dev->power.deferred_resume = false;
1490 dev->power.accounting_timestamp = jiffies;
1491 INIT_WORK(&dev->power.work, pm_runtime_work);
1492
1493 dev->power.timer_expires = 0;
1494 timer_setup(&dev->power.suspend_timer, pm_suspend_timer_fn, 0);
1495
1496 init_waitqueue_head(&dev->power.wait_queue);
1497}
1498
1499/**
1500 * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1501 * @dev: Device object to re-initialize.
1502 */
1503void pm_runtime_reinit(struct device *dev)
1504{
1505 if (!pm_runtime_enabled(dev)) {
1506 if (dev->power.runtime_status == RPM_ACTIVE)
1507 pm_runtime_set_suspended(dev);
1508 if (dev->power.irq_safe) {
1509 spin_lock_irq(&dev->power.lock);
1510 dev->power.irq_safe = 0;
1511 spin_unlock_irq(&dev->power.lock);
1512 if (dev->parent)
1513 pm_runtime_put(dev->parent);
1514 }
1515 }
1516}
1517
1518/**
1519 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1520 * @dev: Device object being removed from device hierarchy.
1521 */
1522void pm_runtime_remove(struct device *dev)
1523{
1524 __pm_runtime_disable(dev, false);
1525 pm_runtime_reinit(dev);
1526}
1527
1528/**
1529 * pm_runtime_clean_up_links - Prepare links to consumers for driver removal.
1530 * @dev: Device whose driver is going to be removed.
1531 *
1532 * Check links from this device to any consumers and if any of them have active
1533 * runtime PM references to the device, drop the usage counter of the device
1534 * (once per link).
1535 *
1536 * Links with the DL_FLAG_STATELESS flag set are ignored.
1537 *
1538 * Since the device is guaranteed to be runtime-active at the point this is
1539 * called, nothing else needs to be done here.
1540 *
1541 * Moreover, this is called after device_links_busy() has returned 'false', so
1542 * the status of each link is guaranteed to be DL_STATE_SUPPLIER_UNBIND and
1543 * therefore rpm_active can't be manipulated concurrently.
1544 */
1545void pm_runtime_clean_up_links(struct device *dev)
1546{
1547 struct device_link *link;
1548 int idx;
1549
1550 idx = device_links_read_lock();
1551
1552 list_for_each_entry_rcu(link, &dev->links.consumers, s_node) {
1553 if (link->flags & DL_FLAG_STATELESS)
1554 continue;
1555
1556 if (link->rpm_active) {
1557 pm_runtime_put_noidle(dev);
1558 link->rpm_active = false;
1559 }
1560 }
1561
1562 device_links_read_unlock(idx);
1563}
1564
1565/**
1566 * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
1567 * @dev: Consumer device.
1568 */
1569void pm_runtime_get_suppliers(struct device *dev)
1570{
1571 struct device_link *link;
1572 int idx;
1573
1574 idx = device_links_read_lock();
1575
1576 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
1577 if (link->flags & DL_FLAG_PM_RUNTIME)
1578 pm_runtime_get_sync(link->supplier);
1579
1580 device_links_read_unlock(idx);
1581}
1582
1583/**
1584 * pm_runtime_put_suppliers - Drop references to supplier devices.
1585 * @dev: Consumer device.
1586 */
1587void pm_runtime_put_suppliers(struct device *dev)
1588{
1589 struct device_link *link;
1590 int idx;
1591
1592 idx = device_links_read_lock();
1593
1594 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
1595 if (link->flags & DL_FLAG_PM_RUNTIME)
1596 pm_runtime_put(link->supplier);
1597
1598 device_links_read_unlock(idx);
1599}
1600
1601void pm_runtime_new_link(struct device *dev)
1602{
1603 spin_lock_irq(&dev->power.lock);
1604 dev->power.links_count++;
1605 spin_unlock_irq(&dev->power.lock);
1606}
1607
1608void pm_runtime_drop_link(struct device *dev)
1609{
1610 spin_lock_irq(&dev->power.lock);
1611 WARN_ON(dev->power.links_count == 0);
1612 dev->power.links_count--;
1613 spin_unlock_irq(&dev->power.lock);
1614}
1615
1616static bool pm_runtime_need_not_resume(struct device *dev)
1617{
1618 return atomic_read(&dev->power.usage_count) <= 1 &&
1619 (atomic_read(&dev->power.child_count) == 0 ||
1620 dev->power.ignore_children);
1621}
1622
1623/**
1624 * pm_runtime_force_suspend - Force a device into suspend state if needed.
1625 * @dev: Device to suspend.
1626 *
1627 * Disable runtime PM so we safely can check the device's runtime PM status and
1628 * if it is active, invoke its ->runtime_suspend callback to suspend it and
1629 * change its runtime PM status field to RPM_SUSPENDED. Also, if the device's
1630 * usage and children counters don't indicate that the device was in use before
1631 * the system-wide transition under way, decrement its parent's children counter
1632 * (if there is a parent). Keep runtime PM disabled to preserve the state
1633 * unless we encounter errors.
1634 *
1635 * Typically this function may be invoked from a system suspend callback to make
1636 * sure the device is put into low power state and it should only be used during
1637 * system-wide PM transitions to sleep states. It assumes that the analogous
1638 * pm_runtime_force_resume() will be used to resume the device.
1639 */
1640int pm_runtime_force_suspend(struct device *dev)
1641{
1642 int (*callback)(struct device *);
1643 int ret;
1644
1645 pm_runtime_disable(dev);
1646 if (pm_runtime_status_suspended(dev))
1647 return 0;
1648
1649 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1650
1651 ret = callback ? callback(dev) : 0;
1652 if (ret)
1653 goto err;
1654
1655 /*
1656 * If the device can stay in suspend after the system-wide transition
1657 * to the working state that will follow, drop the children counter of
1658 * its parent, but set its status to RPM_SUSPENDED anyway in case this
1659 * function will be called again for it in the meantime.
1660 */
1661 if (pm_runtime_need_not_resume(dev))
1662 pm_runtime_set_suspended(dev);
1663 else
1664 __update_runtime_status(dev, RPM_SUSPENDED);
1665
1666 return 0;
1667
1668err:
1669 pm_runtime_enable(dev);
1670 return ret;
1671}
1672EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1673
1674/**
1675 * pm_runtime_force_resume - Force a device into resume state if needed.
1676 * @dev: Device to resume.
1677 *
1678 * Prior invoking this function we expect the user to have brought the device
1679 * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1680 * those actions and bring the device into full power, if it is expected to be
1681 * used on system resume. In the other case, we defer the resume to be managed
1682 * via runtime PM.
1683 *
1684 * Typically this function may be invoked from a system resume callback.
1685 */
1686int pm_runtime_force_resume(struct device *dev)
1687{
1688 int (*callback)(struct device *);
1689 int ret = 0;
1690
1691 if (!pm_runtime_status_suspended(dev) || pm_runtime_need_not_resume(dev))
1692 goto out;
1693
1694 /*
1695 * The value of the parent's children counter is correct already, so
1696 * just update the status of the device.
1697 */
1698 __update_runtime_status(dev, RPM_ACTIVE);
1699
1700 callback = RPM_GET_CALLBACK(dev, runtime_resume);
1701
1702 ret = callback ? callback(dev) : 0;
1703 if (ret) {
1704 pm_runtime_set_suspended(dev);
1705 goto out;
1706 }
1707
1708 pm_runtime_mark_last_busy(dev);
1709out:
1710 pm_runtime_enable(dev);
1711 return ret;
1712}
1713EXPORT_SYMBOL_GPL(pm_runtime_force_resume);