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