PM / Runtime: Replace boolean arguments with bitflags
[linux-2.6.git] / drivers / base / power / runtime.c
1 /*
2  * drivers/base/power/runtime.c - Helper functions for device run-time PM
3  *
4  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5  *
6  * This file is released under the GPLv2.
7  */
8
9 #include <linux/sched.h>
10 #include <linux/pm_runtime.h>
11 #include <linux/jiffies.h>
12
13 static int __pm_runtime_resume(struct device *dev, int rpmflags);
14 static int __pm_request_idle(struct device *dev);
15 static int __pm_request_resume(struct device *dev);
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  */
28 void 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
49 static 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  */
59 static 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  */
71 static 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_idle - Notify device bus type if the device can be suspended.
83  * @dev: Device to notify the bus type about.
84  *
85  * This function must be called under dev->power.lock with interrupts disabled.
86  */
87 static int __pm_runtime_idle(struct device *dev)
88         __releases(&dev->power.lock) __acquires(&dev->power.lock)
89 {
90         int retval = 0;
91
92         if (dev->power.runtime_error)
93                 retval = -EINVAL;
94         else if (dev->power.idle_notification)
95                 retval = -EINPROGRESS;
96         else if (atomic_read(&dev->power.usage_count) > 0
97             || dev->power.disable_depth > 0
98             || dev->power.runtime_status != RPM_ACTIVE)
99                 retval = -EAGAIN;
100         else if (!pm_children_suspended(dev))
101                 retval = -EBUSY;
102         if (retval)
103                 goto out;
104
105         if (dev->power.request_pending) {
106                 /*
107                  * If an idle notification request is pending, cancel it.  Any
108                  * other pending request takes precedence over us.
109                  */
110                 if (dev->power.request == RPM_REQ_IDLE) {
111                         dev->power.request = RPM_REQ_NONE;
112                 } else if (dev->power.request != RPM_REQ_NONE) {
113                         retval = -EAGAIN;
114                         goto out;
115                 }
116         }
117
118         dev->power.idle_notification = true;
119
120         if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_idle) {
121                 spin_unlock_irq(&dev->power.lock);
122
123                 dev->bus->pm->runtime_idle(dev);
124
125                 spin_lock_irq(&dev->power.lock);
126         } else if (dev->type && dev->type->pm && dev->type->pm->runtime_idle) {
127                 spin_unlock_irq(&dev->power.lock);
128
129                 dev->type->pm->runtime_idle(dev);
130
131                 spin_lock_irq(&dev->power.lock);
132         } else if (dev->class && dev->class->pm
133             && dev->class->pm->runtime_idle) {
134                 spin_unlock_irq(&dev->power.lock);
135
136                 dev->class->pm->runtime_idle(dev);
137
138                 spin_lock_irq(&dev->power.lock);
139         }
140
141         dev->power.idle_notification = false;
142         wake_up_all(&dev->power.wait_queue);
143
144  out:
145         return retval;
146 }
147
148 /**
149  * pm_runtime_idle - Notify device bus type if the device can be suspended.
150  * @dev: Device to notify the bus type about.
151  */
152 int pm_runtime_idle(struct device *dev)
153 {
154         int retval;
155
156         spin_lock_irq(&dev->power.lock);
157         retval = __pm_runtime_idle(dev);
158         spin_unlock_irq(&dev->power.lock);
159
160         return retval;
161 }
162 EXPORT_SYMBOL_GPL(pm_runtime_idle);
163
164 /**
165  * __pm_runtime_suspend - Carry out run-time suspend of given device.
166  * @dev: Device to suspend.
167  * @rpmflags: Flag bits.
168  *
169  * Check if the device can be suspended and run the ->runtime_suspend() callback
170  * provided by its bus type.  If another suspend has been started earlier,
171  * either return immediately or wait for it to finish, depending on the
172  * RPM_NOWAIT flag.  If an idle notification or suspend request is pending or
173  * scheduled, cancel it.
174  *
175  * This function must be called under dev->power.lock with interrupts disabled.
176  */
177 static int __pm_runtime_suspend(struct device *dev, int rpmflags)
178         __releases(&dev->power.lock) __acquires(&dev->power.lock)
179 {
180         struct device *parent = NULL;
181         bool notify = false;
182         int retval = 0;
183
184         dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
185
186  repeat:
187         if (dev->power.runtime_error) {
188                 retval = -EINVAL;
189                 goto out;
190         }
191
192         /* Pending resume requests take precedence over us. */
193         if (dev->power.request_pending
194             && dev->power.request == RPM_REQ_RESUME) {
195                 retval = -EAGAIN;
196                 goto out;
197         }
198
199         /* Other scheduled or pending requests need to be canceled. */
200         pm_runtime_cancel_pending(dev);
201
202         if (dev->power.runtime_status == RPM_SUSPENDED)
203                 retval = 1;
204         else if (dev->power.runtime_status == RPM_RESUMING
205             || dev->power.disable_depth > 0
206             || atomic_read(&dev->power.usage_count) > 0)
207                 retval = -EAGAIN;
208         else if (!pm_children_suspended(dev))
209                 retval = -EBUSY;
210         if (retval)
211                 goto out;
212
213         if (dev->power.runtime_status == RPM_SUSPENDING) {
214                 DEFINE_WAIT(wait);
215
216                 if (rpmflags & RPM_NOWAIT) {
217                         retval = -EINPROGRESS;
218                         goto out;
219                 }
220
221                 /* Wait for the other suspend running in parallel with us. */
222                 for (;;) {
223                         prepare_to_wait(&dev->power.wait_queue, &wait,
224                                         TASK_UNINTERRUPTIBLE);
225                         if (dev->power.runtime_status != RPM_SUSPENDING)
226                                 break;
227
228                         spin_unlock_irq(&dev->power.lock);
229
230                         schedule();
231
232                         spin_lock_irq(&dev->power.lock);
233                 }
234                 finish_wait(&dev->power.wait_queue, &wait);
235                 goto repeat;
236         }
237
238         __update_runtime_status(dev, RPM_SUSPENDING);
239         dev->power.deferred_resume = false;
240
241         if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend) {
242                 spin_unlock_irq(&dev->power.lock);
243
244                 retval = dev->bus->pm->runtime_suspend(dev);
245
246                 spin_lock_irq(&dev->power.lock);
247                 dev->power.runtime_error = retval;
248         } else if (dev->type && dev->type->pm
249             && dev->type->pm->runtime_suspend) {
250                 spin_unlock_irq(&dev->power.lock);
251
252                 retval = dev->type->pm->runtime_suspend(dev);
253
254                 spin_lock_irq(&dev->power.lock);
255                 dev->power.runtime_error = retval;
256         } else if (dev->class && dev->class->pm
257             && dev->class->pm->runtime_suspend) {
258                 spin_unlock_irq(&dev->power.lock);
259
260                 retval = dev->class->pm->runtime_suspend(dev);
261
262                 spin_lock_irq(&dev->power.lock);
263                 dev->power.runtime_error = retval;
264         } else {
265                 retval = -ENOSYS;
266         }
267
268         if (retval) {
269                 __update_runtime_status(dev, RPM_ACTIVE);
270                 if (retval == -EAGAIN || retval == -EBUSY) {
271                         if (dev->power.timer_expires == 0)
272                                 notify = true;
273                         dev->power.runtime_error = 0;
274                 } else {
275                         pm_runtime_cancel_pending(dev);
276                 }
277         } else {
278                 __update_runtime_status(dev, RPM_SUSPENDED);
279                 pm_runtime_deactivate_timer(dev);
280
281                 if (dev->parent) {
282                         parent = dev->parent;
283                         atomic_add_unless(&parent->power.child_count, -1, 0);
284                 }
285         }
286         wake_up_all(&dev->power.wait_queue);
287
288         if (dev->power.deferred_resume) {
289                 __pm_runtime_resume(dev, 0);
290                 retval = -EAGAIN;
291                 goto out;
292         }
293
294         if (notify)
295                 __pm_runtime_idle(dev);
296
297         if (parent && !parent->power.ignore_children) {
298                 spin_unlock_irq(&dev->power.lock);
299
300                 pm_request_idle(parent);
301
302                 spin_lock_irq(&dev->power.lock);
303         }
304
305  out:
306         dev_dbg(dev, "%s returns %d\n", __func__, retval);
307
308         return retval;
309 }
310
311 /**
312  * pm_runtime_suspend - Carry out run-time suspend of given device.
313  * @dev: Device to suspend.
314  */
315 int pm_runtime_suspend(struct device *dev)
316 {
317         int retval;
318
319         spin_lock_irq(&dev->power.lock);
320         retval = __pm_runtime_suspend(dev, 0);
321         spin_unlock_irq(&dev->power.lock);
322
323         return retval;
324 }
325 EXPORT_SYMBOL_GPL(pm_runtime_suspend);
326
327 /**
328  * __pm_runtime_resume - Carry out run-time resume of given device.
329  * @dev: Device to resume.
330  * @rpmflags: Flag bits.
331  *
332  * Check if the device can be woken up and run the ->runtime_resume() callback
333  * provided by its bus type.  If another resume has been started earlier,
334  * either return imediately or wait for it to finish, depending on the
335  * RPM_NOWAIT flag.  If there's a suspend running in parallel with this
336  * function, either tell the other process to resume after suspending
337  * (deferred_resume) or wait for it to finish, depending on the RPM_NOWAIT
338  * flag.  Cancel any scheduled or pending requests.
339  *
340  * This function must be called under dev->power.lock with interrupts disabled.
341  */
342 static int __pm_runtime_resume(struct device *dev, int rpmflags)
343         __releases(&dev->power.lock) __acquires(&dev->power.lock)
344 {
345         struct device *parent = NULL;
346         int retval = 0;
347
348         dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
349
350  repeat:
351         if (dev->power.runtime_error) {
352                 retval = -EINVAL;
353                 goto out;
354         }
355
356         pm_runtime_cancel_pending(dev);
357
358         if (dev->power.runtime_status == RPM_ACTIVE)
359                 retval = 1;
360         else if (dev->power.disable_depth > 0)
361                 retval = -EAGAIN;
362         if (retval)
363                 goto out;
364
365         if (dev->power.runtime_status == RPM_RESUMING
366             || dev->power.runtime_status == RPM_SUSPENDING) {
367                 DEFINE_WAIT(wait);
368
369                 if (rpmflags & RPM_NOWAIT) {
370                         if (dev->power.runtime_status == RPM_SUSPENDING)
371                                 dev->power.deferred_resume = true;
372                         retval = -EINPROGRESS;
373                         goto out;
374                 }
375
376                 /* Wait for the operation carried out in parallel with us. */
377                 for (;;) {
378                         prepare_to_wait(&dev->power.wait_queue, &wait,
379                                         TASK_UNINTERRUPTIBLE);
380                         if (dev->power.runtime_status != RPM_RESUMING
381                             && dev->power.runtime_status != RPM_SUSPENDING)
382                                 break;
383
384                         spin_unlock_irq(&dev->power.lock);
385
386                         schedule();
387
388                         spin_lock_irq(&dev->power.lock);
389                 }
390                 finish_wait(&dev->power.wait_queue, &wait);
391                 goto repeat;
392         }
393
394         if (!parent && dev->parent) {
395                 /*
396                  * Increment the parent's resume counter and resume it if
397                  * necessary.
398                  */
399                 parent = dev->parent;
400                 spin_unlock(&dev->power.lock);
401
402                 pm_runtime_get_noresume(parent);
403
404                 spin_lock(&parent->power.lock);
405                 /*
406                  * We can resume if the parent's run-time PM is disabled or it
407                  * is set to ignore children.
408                  */
409                 if (!parent->power.disable_depth
410                     && !parent->power.ignore_children) {
411                         __pm_runtime_resume(parent, 0);
412                         if (parent->power.runtime_status != RPM_ACTIVE)
413                                 retval = -EBUSY;
414                 }
415                 spin_unlock(&parent->power.lock);
416
417                 spin_lock(&dev->power.lock);
418                 if (retval)
419                         goto out;
420                 goto repeat;
421         }
422
423         __update_runtime_status(dev, RPM_RESUMING);
424
425         if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume) {
426                 spin_unlock_irq(&dev->power.lock);
427
428                 retval = dev->bus->pm->runtime_resume(dev);
429
430                 spin_lock_irq(&dev->power.lock);
431                 dev->power.runtime_error = retval;
432         } else if (dev->type && dev->type->pm
433             && dev->type->pm->runtime_resume) {
434                 spin_unlock_irq(&dev->power.lock);
435
436                 retval = dev->type->pm->runtime_resume(dev);
437
438                 spin_lock_irq(&dev->power.lock);
439                 dev->power.runtime_error = retval;
440         } else if (dev->class && dev->class->pm
441             && dev->class->pm->runtime_resume) {
442                 spin_unlock_irq(&dev->power.lock);
443
444                 retval = dev->class->pm->runtime_resume(dev);
445
446                 spin_lock_irq(&dev->power.lock);
447                 dev->power.runtime_error = retval;
448         } else {
449                 retval = -ENOSYS;
450         }
451
452         if (retval) {
453                 __update_runtime_status(dev, RPM_SUSPENDED);
454                 pm_runtime_cancel_pending(dev);
455         } else {
456                 __update_runtime_status(dev, RPM_ACTIVE);
457                 if (parent)
458                         atomic_inc(&parent->power.child_count);
459         }
460         wake_up_all(&dev->power.wait_queue);
461
462         if (!retval)
463                 __pm_request_idle(dev);
464
465  out:
466         if (parent) {
467                 spin_unlock_irq(&dev->power.lock);
468
469                 pm_runtime_put(parent);
470
471                 spin_lock_irq(&dev->power.lock);
472         }
473
474         dev_dbg(dev, "%s returns %d\n", __func__, retval);
475
476         return retval;
477 }
478
479 /**
480  * pm_runtime_resume - Carry out run-time resume of given device.
481  * @dev: Device to suspend.
482  */
483 int pm_runtime_resume(struct device *dev)
484 {
485         int retval;
486
487         spin_lock_irq(&dev->power.lock);
488         retval = __pm_runtime_resume(dev, 0);
489         spin_unlock_irq(&dev->power.lock);
490
491         return retval;
492 }
493 EXPORT_SYMBOL_GPL(pm_runtime_resume);
494
495 /**
496  * pm_runtime_work - Universal run-time PM work function.
497  * @work: Work structure used for scheduling the execution of this function.
498  *
499  * Use @work to get the device object the work is to be done for, determine what
500  * is to be done and execute the appropriate run-time PM function.
501  */
502 static void pm_runtime_work(struct work_struct *work)
503 {
504         struct device *dev = container_of(work, struct device, power.work);
505         enum rpm_request req;
506
507         spin_lock_irq(&dev->power.lock);
508
509         if (!dev->power.request_pending)
510                 goto out;
511
512         req = dev->power.request;
513         dev->power.request = RPM_REQ_NONE;
514         dev->power.request_pending = false;
515
516         switch (req) {
517         case RPM_REQ_NONE:
518                 break;
519         case RPM_REQ_IDLE:
520                 __pm_runtime_idle(dev);
521                 break;
522         case RPM_REQ_SUSPEND:
523                 __pm_runtime_suspend(dev, RPM_NOWAIT);
524                 break;
525         case RPM_REQ_RESUME:
526                 __pm_runtime_resume(dev, RPM_NOWAIT);
527                 break;
528         }
529
530  out:
531         spin_unlock_irq(&dev->power.lock);
532 }
533
534 /**
535  * __pm_request_idle - Submit an idle notification request for given device.
536  * @dev: Device to handle.
537  *
538  * Check if the device's run-time PM status is correct for suspending the device
539  * and queue up a request to run __pm_runtime_idle() for it.
540  *
541  * This function must be called under dev->power.lock with interrupts disabled.
542  */
543 static int __pm_request_idle(struct device *dev)
544 {
545         int retval = 0;
546
547         if (dev->power.runtime_error)
548                 retval = -EINVAL;
549         else if (atomic_read(&dev->power.usage_count) > 0
550             || dev->power.disable_depth > 0
551             || dev->power.runtime_status == RPM_SUSPENDED
552             || dev->power.runtime_status == RPM_SUSPENDING)
553                 retval = -EAGAIN;
554         else if (!pm_children_suspended(dev))
555                 retval = -EBUSY;
556         if (retval)
557                 return retval;
558
559         if (dev->power.request_pending) {
560                 /* Any requests other then RPM_REQ_IDLE take precedence. */
561                 if (dev->power.request == RPM_REQ_NONE)
562                         dev->power.request = RPM_REQ_IDLE;
563                 else if (dev->power.request != RPM_REQ_IDLE)
564                         retval = -EAGAIN;
565                 return retval;
566         }
567
568         dev->power.request = RPM_REQ_IDLE;
569         dev->power.request_pending = true;
570         queue_work(pm_wq, &dev->power.work);
571
572         return retval;
573 }
574
575 /**
576  * pm_request_idle - Submit an idle notification request for given device.
577  * @dev: Device to handle.
578  */
579 int pm_request_idle(struct device *dev)
580 {
581         unsigned long flags;
582         int retval;
583
584         spin_lock_irqsave(&dev->power.lock, flags);
585         retval = __pm_request_idle(dev);
586         spin_unlock_irqrestore(&dev->power.lock, flags);
587
588         return retval;
589 }
590 EXPORT_SYMBOL_GPL(pm_request_idle);
591
592 /**
593  * __pm_request_suspend - Submit a suspend request for given device.
594  * @dev: Device to suspend.
595  *
596  * This function must be called under dev->power.lock with interrupts disabled.
597  */
598 static int __pm_request_suspend(struct device *dev)
599 {
600         int retval = 0;
601
602         if (dev->power.runtime_error)
603                 return -EINVAL;
604
605         if (dev->power.runtime_status == RPM_SUSPENDED)
606                 retval = 1;
607         else if (atomic_read(&dev->power.usage_count) > 0
608             || dev->power.disable_depth > 0)
609                 retval = -EAGAIN;
610         else if (dev->power.runtime_status == RPM_SUSPENDING)
611                 retval = -EINPROGRESS;
612         else if (!pm_children_suspended(dev))
613                 retval = -EBUSY;
614         if (retval < 0)
615                 return retval;
616
617         pm_runtime_deactivate_timer(dev);
618
619         if (dev->power.request_pending) {
620                 /*
621                  * Pending resume requests take precedence over us, but we can
622                  * overtake any other pending request.
623                  */
624                 if (dev->power.request == RPM_REQ_RESUME)
625                         retval = -EAGAIN;
626                 else if (dev->power.request != RPM_REQ_SUSPEND)
627                         dev->power.request = retval ?
628                                                 RPM_REQ_NONE : RPM_REQ_SUSPEND;
629                 return retval;
630         } else if (retval) {
631                 return retval;
632         }
633
634         dev->power.request = RPM_REQ_SUSPEND;
635         dev->power.request_pending = true;
636         queue_work(pm_wq, &dev->power.work);
637
638         return 0;
639 }
640
641 /**
642  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
643  * @data: Device pointer passed by pm_schedule_suspend().
644  *
645  * Check if the time is right and execute __pm_request_suspend() in that case.
646  */
647 static void pm_suspend_timer_fn(unsigned long data)
648 {
649         struct device *dev = (struct device *)data;
650         unsigned long flags;
651         unsigned long expires;
652
653         spin_lock_irqsave(&dev->power.lock, flags);
654
655         expires = dev->power.timer_expires;
656         /* If 'expire' is after 'jiffies' we've been called too early. */
657         if (expires > 0 && !time_after(expires, jiffies)) {
658                 dev->power.timer_expires = 0;
659                 __pm_request_suspend(dev);
660         }
661
662         spin_unlock_irqrestore(&dev->power.lock, flags);
663 }
664
665 /**
666  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
667  * @dev: Device to suspend.
668  * @delay: Time to wait before submitting a suspend request, in milliseconds.
669  */
670 int pm_schedule_suspend(struct device *dev, unsigned int delay)
671 {
672         unsigned long flags;
673         int retval = 0;
674
675         spin_lock_irqsave(&dev->power.lock, flags);
676
677         if (dev->power.runtime_error) {
678                 retval = -EINVAL;
679                 goto out;
680         }
681
682         if (!delay) {
683                 retval = __pm_request_suspend(dev);
684                 goto out;
685         }
686
687         pm_runtime_deactivate_timer(dev);
688
689         if (dev->power.request_pending) {
690                 /*
691                  * Pending resume requests take precedence over us, but any
692                  * other pending requests have to be canceled.
693                  */
694                 if (dev->power.request == RPM_REQ_RESUME) {
695                         retval = -EAGAIN;
696                         goto out;
697                 }
698                 dev->power.request = RPM_REQ_NONE;
699         }
700
701         if (dev->power.runtime_status == RPM_SUSPENDED)
702                 retval = 1;
703         else if (atomic_read(&dev->power.usage_count) > 0
704             || dev->power.disable_depth > 0)
705                 retval = -EAGAIN;
706         else if (!pm_children_suspended(dev))
707                 retval = -EBUSY;
708         if (retval)
709                 goto out;
710
711         dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
712         if (!dev->power.timer_expires)
713                 dev->power.timer_expires = 1;
714         mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
715
716  out:
717         spin_unlock_irqrestore(&dev->power.lock, flags);
718
719         return retval;
720 }
721 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
722
723 /**
724  * pm_request_resume - Submit a resume request for given device.
725  * @dev: Device to resume.
726  *
727  * This function must be called under dev->power.lock with interrupts disabled.
728  */
729 static int __pm_request_resume(struct device *dev)
730 {
731         int retval = 0;
732
733         if (dev->power.runtime_error)
734                 return -EINVAL;
735
736         if (dev->power.runtime_status == RPM_ACTIVE)
737                 retval = 1;
738         else if (dev->power.runtime_status == RPM_RESUMING)
739                 retval = -EINPROGRESS;
740         else if (dev->power.disable_depth > 0)
741                 retval = -EAGAIN;
742         if (retval < 0)
743                 return retval;
744
745         pm_runtime_deactivate_timer(dev);
746
747         if (dev->power.runtime_status == RPM_SUSPENDING) {
748                 dev->power.deferred_resume = true;
749                 return retval;
750         }
751         if (dev->power.request_pending) {
752                 /* If non-resume request is pending, we can overtake it. */
753                 dev->power.request = retval ? RPM_REQ_NONE : RPM_REQ_RESUME;
754                 return retval;
755         }
756         if (retval)
757                 return retval;
758
759         dev->power.request = RPM_REQ_RESUME;
760         dev->power.request_pending = true;
761         queue_work(pm_wq, &dev->power.work);
762
763         return retval;
764 }
765
766 /**
767  * pm_request_resume - Submit a resume request for given device.
768  * @dev: Device to resume.
769  */
770 int pm_request_resume(struct device *dev)
771 {
772         unsigned long flags;
773         int retval;
774
775         spin_lock_irqsave(&dev->power.lock, flags);
776         retval = __pm_request_resume(dev);
777         spin_unlock_irqrestore(&dev->power.lock, flags);
778
779         return retval;
780 }
781 EXPORT_SYMBOL_GPL(pm_request_resume);
782
783 /**
784  * __pm_runtime_get - Reference count a device and wake it up, if necessary.
785  * @dev: Device to handle.
786  * @rpmflags: Flag bits.
787  *
788  * Increment the usage count of the device and resume it or submit a resume
789  * request for it, depending on the RPM_ASYNC flag bit.
790  */
791 int __pm_runtime_get(struct device *dev, int rpmflags)
792 {
793         int retval;
794
795         atomic_inc(&dev->power.usage_count);
796         retval = (rpmflags & RPM_ASYNC) ?
797             pm_request_resume(dev) : pm_runtime_resume(dev);
798
799         return retval;
800 }
801 EXPORT_SYMBOL_GPL(__pm_runtime_get);
802
803 /**
804  * __pm_runtime_put - Decrement the device's usage counter and notify its bus.
805  * @dev: Device to handle.
806  * @rpmflags: Flag bits.
807  *
808  * Decrement the usage count of the device and if it reaches zero, carry out a
809  * synchronous idle notification or submit an idle notification request for it,
810  * depending on the RPM_ASYNC flag bit.
811  */
812 int __pm_runtime_put(struct device *dev, int rpmflags)
813 {
814         int retval = 0;
815
816         if (atomic_dec_and_test(&dev->power.usage_count))
817                 retval = (rpmflags & RPM_ASYNC) ?
818                     pm_request_idle(dev) : pm_runtime_idle(dev);
819
820         return retval;
821 }
822 EXPORT_SYMBOL_GPL(__pm_runtime_put);
823
824 /**
825  * __pm_runtime_set_status - Set run-time PM status of a device.
826  * @dev: Device to handle.
827  * @status: New run-time PM status of the device.
828  *
829  * If run-time PM of the device is disabled or its power.runtime_error field is
830  * different from zero, the status may be changed either to RPM_ACTIVE, or to
831  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
832  * However, if the device has a parent and the parent is not active, and the
833  * parent's power.ignore_children flag is unset, the device's status cannot be
834  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
835  *
836  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
837  * and the device parent's counter of unsuspended children is modified to
838  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
839  * notification request for the parent is submitted.
840  */
841 int __pm_runtime_set_status(struct device *dev, unsigned int status)
842 {
843         struct device *parent = dev->parent;
844         unsigned long flags;
845         bool notify_parent = false;
846         int error = 0;
847
848         if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
849                 return -EINVAL;
850
851         spin_lock_irqsave(&dev->power.lock, flags);
852
853         if (!dev->power.runtime_error && !dev->power.disable_depth) {
854                 error = -EAGAIN;
855                 goto out;
856         }
857
858         if (dev->power.runtime_status == status)
859                 goto out_set;
860
861         if (status == RPM_SUSPENDED) {
862                 /* It always is possible to set the status to 'suspended'. */
863                 if (parent) {
864                         atomic_add_unless(&parent->power.child_count, -1, 0);
865                         notify_parent = !parent->power.ignore_children;
866                 }
867                 goto out_set;
868         }
869
870         if (parent) {
871                 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
872
873                 /*
874                  * It is invalid to put an active child under a parent that is
875                  * not active, has run-time PM enabled and the
876                  * 'power.ignore_children' flag unset.
877                  */
878                 if (!parent->power.disable_depth
879                     && !parent->power.ignore_children
880                     && parent->power.runtime_status != RPM_ACTIVE)
881                         error = -EBUSY;
882                 else if (dev->power.runtime_status == RPM_SUSPENDED)
883                         atomic_inc(&parent->power.child_count);
884
885                 spin_unlock(&parent->power.lock);
886
887                 if (error)
888                         goto out;
889         }
890
891  out_set:
892         __update_runtime_status(dev, status);
893         dev->power.runtime_error = 0;
894  out:
895         spin_unlock_irqrestore(&dev->power.lock, flags);
896
897         if (notify_parent)
898                 pm_request_idle(parent);
899
900         return error;
901 }
902 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
903
904 /**
905  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
906  * @dev: Device to handle.
907  *
908  * Flush all pending requests for the device from pm_wq and wait for all
909  * run-time PM operations involving the device in progress to complete.
910  *
911  * Should be called under dev->power.lock with interrupts disabled.
912  */
913 static void __pm_runtime_barrier(struct device *dev)
914 {
915         pm_runtime_deactivate_timer(dev);
916
917         if (dev->power.request_pending) {
918                 dev->power.request = RPM_REQ_NONE;
919                 spin_unlock_irq(&dev->power.lock);
920
921                 cancel_work_sync(&dev->power.work);
922
923                 spin_lock_irq(&dev->power.lock);
924                 dev->power.request_pending = false;
925         }
926
927         if (dev->power.runtime_status == RPM_SUSPENDING
928             || dev->power.runtime_status == RPM_RESUMING
929             || dev->power.idle_notification) {
930                 DEFINE_WAIT(wait);
931
932                 /* Suspend, wake-up or idle notification in progress. */
933                 for (;;) {
934                         prepare_to_wait(&dev->power.wait_queue, &wait,
935                                         TASK_UNINTERRUPTIBLE);
936                         if (dev->power.runtime_status != RPM_SUSPENDING
937                             && dev->power.runtime_status != RPM_RESUMING
938                             && !dev->power.idle_notification)
939                                 break;
940                         spin_unlock_irq(&dev->power.lock);
941
942                         schedule();
943
944                         spin_lock_irq(&dev->power.lock);
945                 }
946                 finish_wait(&dev->power.wait_queue, &wait);
947         }
948 }
949
950 /**
951  * pm_runtime_barrier - Flush pending requests and wait for completions.
952  * @dev: Device to handle.
953  *
954  * Prevent the device from being suspended by incrementing its usage counter and
955  * if there's a pending resume request for the device, wake the device up.
956  * Next, make sure that all pending requests for the device have been flushed
957  * from pm_wq and wait for all run-time PM operations involving the device in
958  * progress to complete.
959  *
960  * Return value:
961  * 1, if there was a resume request pending and the device had to be woken up,
962  * 0, otherwise
963  */
964 int pm_runtime_barrier(struct device *dev)
965 {
966         int retval = 0;
967
968         pm_runtime_get_noresume(dev);
969         spin_lock_irq(&dev->power.lock);
970
971         if (dev->power.request_pending
972             && dev->power.request == RPM_REQ_RESUME) {
973                 __pm_runtime_resume(dev, 0);
974                 retval = 1;
975         }
976
977         __pm_runtime_barrier(dev);
978
979         spin_unlock_irq(&dev->power.lock);
980         pm_runtime_put_noidle(dev);
981
982         return retval;
983 }
984 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
985
986 /**
987  * __pm_runtime_disable - Disable run-time PM of a device.
988  * @dev: Device to handle.
989  * @check_resume: If set, check if there's a resume request for the device.
990  *
991  * Increment power.disable_depth for the device and if was zero previously,
992  * cancel all pending run-time PM requests for the device and wait for all
993  * operations in progress to complete.  The device can be either active or
994  * suspended after its run-time PM has been disabled.
995  *
996  * If @check_resume is set and there's a resume request pending when
997  * __pm_runtime_disable() is called and power.disable_depth is zero, the
998  * function will wake up the device before disabling its run-time PM.
999  */
1000 void __pm_runtime_disable(struct device *dev, bool check_resume)
1001 {
1002         spin_lock_irq(&dev->power.lock);
1003
1004         if (dev->power.disable_depth > 0) {
1005                 dev->power.disable_depth++;
1006                 goto out;
1007         }
1008
1009         /*
1010          * Wake up the device if there's a resume request pending, because that
1011          * means there probably is some I/O to process and disabling run-time PM
1012          * shouldn't prevent the device from processing the I/O.
1013          */
1014         if (check_resume && dev->power.request_pending
1015             && dev->power.request == RPM_REQ_RESUME) {
1016                 /*
1017                  * Prevent suspends and idle notifications from being carried
1018                  * out after we have woken up the device.
1019                  */
1020                 pm_runtime_get_noresume(dev);
1021
1022                 __pm_runtime_resume(dev, 0);
1023
1024                 pm_runtime_put_noidle(dev);
1025         }
1026
1027         if (!dev->power.disable_depth++)
1028                 __pm_runtime_barrier(dev);
1029
1030  out:
1031         spin_unlock_irq(&dev->power.lock);
1032 }
1033 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1034
1035 /**
1036  * pm_runtime_enable - Enable run-time PM of a device.
1037  * @dev: Device to handle.
1038  */
1039 void pm_runtime_enable(struct device *dev)
1040 {
1041         unsigned long flags;
1042
1043         spin_lock_irqsave(&dev->power.lock, flags);
1044
1045         if (dev->power.disable_depth > 0)
1046                 dev->power.disable_depth--;
1047         else
1048                 dev_warn(dev, "Unbalanced %s!\n", __func__);
1049
1050         spin_unlock_irqrestore(&dev->power.lock, flags);
1051 }
1052 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1053
1054 /**
1055  * pm_runtime_forbid - Block run-time PM of a device.
1056  * @dev: Device to handle.
1057  *
1058  * Increase the device's usage count and clear its power.runtime_auto flag,
1059  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1060  * for it.
1061  */
1062 void pm_runtime_forbid(struct device *dev)
1063 {
1064         spin_lock_irq(&dev->power.lock);
1065         if (!dev->power.runtime_auto)
1066                 goto out;
1067
1068         dev->power.runtime_auto = false;
1069         atomic_inc(&dev->power.usage_count);
1070         __pm_runtime_resume(dev, 0);
1071
1072  out:
1073         spin_unlock_irq(&dev->power.lock);
1074 }
1075 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1076
1077 /**
1078  * pm_runtime_allow - Unblock run-time PM of a device.
1079  * @dev: Device to handle.
1080  *
1081  * Decrease the device's usage count and set its power.runtime_auto flag.
1082  */
1083 void pm_runtime_allow(struct device *dev)
1084 {
1085         spin_lock_irq(&dev->power.lock);
1086         if (dev->power.runtime_auto)
1087                 goto out;
1088
1089         dev->power.runtime_auto = true;
1090         if (atomic_dec_and_test(&dev->power.usage_count))
1091                 __pm_runtime_idle(dev);
1092
1093  out:
1094         spin_unlock_irq(&dev->power.lock);
1095 }
1096 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1097
1098 /**
1099  * pm_runtime_init - Initialize run-time PM fields in given device object.
1100  * @dev: Device object to initialize.
1101  */
1102 void pm_runtime_init(struct device *dev)
1103 {
1104         dev->power.runtime_status = RPM_SUSPENDED;
1105         dev->power.idle_notification = false;
1106
1107         dev->power.disable_depth = 1;
1108         atomic_set(&dev->power.usage_count, 0);
1109
1110         dev->power.runtime_error = 0;
1111
1112         atomic_set(&dev->power.child_count, 0);
1113         pm_suspend_ignore_children(dev, false);
1114         dev->power.runtime_auto = true;
1115
1116         dev->power.request_pending = false;
1117         dev->power.request = RPM_REQ_NONE;
1118         dev->power.deferred_resume = false;
1119         dev->power.accounting_timestamp = jiffies;
1120         INIT_WORK(&dev->power.work, pm_runtime_work);
1121
1122         dev->power.timer_expires = 0;
1123         setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1124                         (unsigned long)dev);
1125
1126         init_waitqueue_head(&dev->power.wait_queue);
1127 }
1128
1129 /**
1130  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1131  * @dev: Device object being removed from device hierarchy.
1132  */
1133 void pm_runtime_remove(struct device *dev)
1134 {
1135         __pm_runtime_disable(dev, false);
1136
1137         /* Change the status back to 'suspended' to match the initial status. */
1138         if (dev->power.runtime_status == RPM_ACTIVE)
1139                 pm_runtime_set_suspended(dev);
1140 }