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