59894873a3b37de88a50d3b5e1f22ce67e454858
[linux-2.6.git] / drivers / base / power / runtime.c
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 <trace/events/rpm.h>
14 #include "power.h"
15
16 static int rpm_resume(struct device *dev, int rpmflags);
17 static int rpm_suspend(struct device *dev, int rpmflags);
18
19 /**
20  * update_pm_runtime_accounting - Update the time accounting of power states
21  * @dev: Device to update the accounting for
22  *
23  * In order to be able to have time accounting of the various power states
24  * (as used by programs such as PowerTOP to show the effectiveness of runtime
25  * PM), we need to track the time spent in each state.
26  * update_pm_runtime_accounting must be called each time before the
27  * runtime_status field is updated, to account the time in the old state
28  * correctly.
29  */
30 void update_pm_runtime_accounting(struct device *dev)
31 {
32         unsigned long now = jiffies;
33         unsigned long delta;
34
35         delta = now - dev->power.accounting_timestamp;
36
37         dev->power.accounting_timestamp = now;
38
39         if (dev->power.disable_depth > 0)
40                 return;
41
42         if (dev->power.runtime_status == RPM_SUSPENDED)
43                 dev->power.suspended_jiffies += delta;
44         else
45                 dev->power.active_jiffies += delta;
46 }
47
48 static void __update_runtime_status(struct device *dev, enum rpm_status status)
49 {
50         update_pm_runtime_accounting(dev);
51         dev->power.runtime_status = status;
52 }
53
54 /**
55  * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
56  * @dev: Device to handle.
57  */
58 static void pm_runtime_deactivate_timer(struct device *dev)
59 {
60         if (dev->power.timer_expires > 0) {
61                 del_timer(&dev->power.suspend_timer);
62                 dev->power.timer_expires = 0;
63         }
64 }
65
66 /**
67  * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
68  * @dev: Device to handle.
69  */
70 static void pm_runtime_cancel_pending(struct device *dev)
71 {
72         pm_runtime_deactivate_timer(dev);
73         /*
74          * In case there's a request pending, make sure its work function will
75          * return without doing anything.
76          */
77         dev->power.request = RPM_REQ_NONE;
78 }
79
80 /*
81  * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
82  * @dev: Device to handle.
83  *
84  * Compute the autosuspend-delay expiration time based on the device's
85  * power.last_busy time.  If the delay has already expired or is disabled
86  * (negative) or the power.use_autosuspend flag isn't set, return 0.
87  * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
88  *
89  * This function may be called either with or without dev->power.lock held.
90  * Either way it can be racy, since power.last_busy may be updated at any time.
91  */
92 unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
93 {
94         int autosuspend_delay;
95         long elapsed;
96         unsigned long last_busy;
97         unsigned long expires = 0;
98
99         if (!dev->power.use_autosuspend)
100                 goto out;
101
102         autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
103         if (autosuspend_delay < 0)
104                 goto out;
105
106         last_busy = ACCESS_ONCE(dev->power.last_busy);
107         elapsed = jiffies - last_busy;
108         if (elapsed < 0)
109                 goto out;       /* jiffies has wrapped around. */
110
111         /*
112          * If the autosuspend_delay is >= 1 second, align the timer by rounding
113          * up to the nearest second.
114          */
115         expires = last_busy + msecs_to_jiffies(autosuspend_delay);
116         if (autosuspend_delay >= 1000)
117                 expires = round_jiffies(expires);
118         expires += !expires;
119         if (elapsed >= expires - last_busy)
120                 expires = 0;    /* Already expired. */
121
122  out:
123         return expires;
124 }
125 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
126
127 /**
128  * rpm_check_suspend_allowed - Test whether a device may be suspended.
129  * @dev: Device to test.
130  */
131 static int rpm_check_suspend_allowed(struct device *dev)
132 {
133         int retval = 0;
134
135         if (dev->power.runtime_error)
136                 retval = -EINVAL;
137         else if (dev->power.disable_depth > 0)
138                 retval = -EACCES;
139         else if (atomic_read(&dev->power.usage_count) > 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_callback - Run a given runtime PM callback for a given device.
158  * @cb: Runtime PM callback to run.
159  * @dev: Device to run the callback for.
160  */
161 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
162         __releases(&dev->power.lock) __acquires(&dev->power.lock)
163 {
164         int retval;
165
166         if (dev->power.irq_safe)
167                 spin_unlock(&dev->power.lock);
168         else
169                 spin_unlock_irq(&dev->power.lock);
170
171         retval = cb(dev);
172
173         if (dev->power.irq_safe)
174                 spin_lock(&dev->power.lock);
175         else
176                 spin_lock_irq(&dev->power.lock);
177
178         return retval;
179 }
180
181 /**
182  * rpm_idle - Notify device bus type if the device can be suspended.
183  * @dev: Device to notify the bus type about.
184  * @rpmflags: Flag bits.
185  *
186  * Check if the device's runtime PM status allows it to be suspended.  If
187  * another idle notification has been started earlier, return immediately.  If
188  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
189  * run the ->runtime_idle() callback directly.
190  *
191  * This function must be called under dev->power.lock with interrupts disabled.
192  */
193 static int rpm_idle(struct device *dev, int rpmflags)
194 {
195         int (*callback)(struct device *);
196         int retval;
197
198         trace_rpm_idle(dev, rpmflags);
199         retval = rpm_check_suspend_allowed(dev);
200         if (retval < 0)
201                 ;       /* Conditions are wrong. */
202
203         /* Idle notifications are allowed only in the RPM_ACTIVE state. */
204         else if (dev->power.runtime_status != RPM_ACTIVE)
205                 retval = -EAGAIN;
206
207         /*
208          * Any pending request other than an idle notification takes
209          * precedence over us, except that the timer may be running.
210          */
211         else if (dev->power.request_pending &&
212             dev->power.request > RPM_REQ_IDLE)
213                 retval = -EAGAIN;
214
215         /* Act as though RPM_NOWAIT is always set. */
216         else if (dev->power.idle_notification)
217                 retval = -EINPROGRESS;
218         if (retval)
219                 goto out;
220
221         /* Pending requests need to be canceled. */
222         dev->power.request = RPM_REQ_NONE;
223
224         if (dev->power.no_callbacks) {
225                 /* Assume ->runtime_idle() callback would have suspended. */
226                 retval = rpm_suspend(dev, rpmflags);
227                 goto out;
228         }
229
230         /* Carry out an asynchronous or a synchronous idle notification. */
231         if (rpmflags & RPM_ASYNC) {
232                 dev->power.request = RPM_REQ_IDLE;
233                 if (!dev->power.request_pending) {
234                         dev->power.request_pending = true;
235                         queue_work(pm_wq, &dev->power.work);
236                 }
237                 goto out;
238         }
239
240         dev->power.idle_notification = true;
241
242         if (dev->pm_domain)
243                 callback = dev->pm_domain->ops.runtime_idle;
244         else if (dev->type && dev->type->pm)
245                 callback = dev->type->pm->runtime_idle;
246         else if (dev->class && dev->class->pm)
247                 callback = dev->class->pm->runtime_idle;
248         else if (dev->bus && dev->bus->pm)
249                 callback = dev->bus->pm->runtime_idle;
250         else
251                 callback = NULL;
252
253         if (!callback && dev->driver && dev->driver->pm)
254                 callback = dev->driver->pm->runtime_idle;
255
256         if (callback)
257                 __rpm_callback(callback, dev);
258
259         dev->power.idle_notification = false;
260         wake_up_all(&dev->power.wait_queue);
261
262  out:
263         trace_rpm_return_int(dev, _THIS_IP_, retval);
264         return retval;
265 }
266
267 /**
268  * rpm_callback - Run a given runtime PM callback for a given device.
269  * @cb: Runtime PM callback to run.
270  * @dev: Device to run the callback for.
271  */
272 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
273 {
274         int retval;
275
276         if (!cb)
277                 return -ENOSYS;
278
279         retval = __rpm_callback(cb, dev);
280
281         dev->power.runtime_error = retval;
282         return retval != -EACCES ? retval : -EIO;
283 }
284
285 /**
286  * rpm_suspend - Carry out runtime suspend of given device.
287  * @dev: Device to suspend.
288  * @rpmflags: Flag bits.
289  *
290  * Check if the device's runtime PM status allows it to be suspended.
291  * Cancel a pending idle notification, autosuspend or suspend. If
292  * another suspend has been started earlier, either return immediately
293  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
294  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
295  * otherwise run the ->runtime_suspend() callback directly. When
296  * ->runtime_suspend succeeded, if a deferred resume was requested while
297  * the callback was running then carry it out, otherwise send an idle
298  * notification for its parent (if the suspend succeeded and both
299  * ignore_children of parent->power and irq_safe of dev->power are not set).
300  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
301  * flag is set and the next autosuspend-delay expiration time is in the
302  * future, schedule another autosuspend attempt.
303  *
304  * This function must be called under dev->power.lock with interrupts disabled.
305  */
306 static int rpm_suspend(struct device *dev, int rpmflags)
307         __releases(&dev->power.lock) __acquires(&dev->power.lock)
308 {
309         int (*callback)(struct device *);
310         struct device *parent = NULL;
311         int retval;
312
313         trace_rpm_suspend(dev, rpmflags);
314
315  repeat:
316         retval = rpm_check_suspend_allowed(dev);
317
318         if (retval < 0)
319                 ;       /* Conditions are wrong. */
320
321         /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
322         else if (dev->power.runtime_status == RPM_RESUMING &&
323             !(rpmflags & RPM_ASYNC))
324                 retval = -EAGAIN;
325         if (retval)
326                 goto out;
327
328         /* If the autosuspend_delay time hasn't expired yet, reschedule. */
329         if ((rpmflags & RPM_AUTO)
330             && dev->power.runtime_status != RPM_SUSPENDING) {
331                 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
332
333                 if (expires != 0) {
334                         /* Pending requests need to be canceled. */
335                         dev->power.request = RPM_REQ_NONE;
336
337                         /*
338                          * Optimization: If the timer is already running and is
339                          * set to expire at or before the autosuspend delay,
340                          * avoid the overhead of resetting it.  Just let it
341                          * expire; pm_suspend_timer_fn() will take care of the
342                          * rest.
343                          */
344                         if (!(dev->power.timer_expires && time_before_eq(
345                             dev->power.timer_expires, expires))) {
346                                 dev->power.timer_expires = expires;
347                                 mod_timer(&dev->power.suspend_timer, expires);
348                         }
349                         dev->power.timer_autosuspends = 1;
350                         goto out;
351                 }
352         }
353
354         /* Other scheduled or pending requests need to be canceled. */
355         pm_runtime_cancel_pending(dev);
356
357         if (dev->power.runtime_status == RPM_SUSPENDING) {
358                 DEFINE_WAIT(wait);
359
360                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
361                         retval = -EINPROGRESS;
362                         goto out;
363                 }
364
365                 if (dev->power.irq_safe) {
366                         spin_unlock(&dev->power.lock);
367
368                         cpu_relax();
369
370                         spin_lock(&dev->power.lock);
371                         goto repeat;
372                 }
373
374                 /* Wait for the other suspend running in parallel with us. */
375                 for (;;) {
376                         prepare_to_wait(&dev->power.wait_queue, &wait,
377                                         TASK_UNINTERRUPTIBLE);
378                         if (dev->power.runtime_status != RPM_SUSPENDING)
379                                 break;
380
381                         spin_unlock_irq(&dev->power.lock);
382
383                         schedule();
384
385                         spin_lock_irq(&dev->power.lock);
386                 }
387                 finish_wait(&dev->power.wait_queue, &wait);
388                 goto repeat;
389         }
390
391         dev->power.deferred_resume = false;
392         if (dev->power.no_callbacks)
393                 goto no_callback;       /* Assume success. */
394
395         /* Carry out an asynchronous or a synchronous suspend. */
396         if (rpmflags & RPM_ASYNC) {
397                 dev->power.request = (rpmflags & RPM_AUTO) ?
398                     RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
399                 if (!dev->power.request_pending) {
400                         dev->power.request_pending = true;
401                         queue_work(pm_wq, &dev->power.work);
402                 }
403                 goto out;
404         }
405
406         if (__dev_pm_qos_read_value(dev) < 0) {
407                 /* Negative PM QoS constraint means "never suspend". */
408                 retval = -EPERM;
409                 goto out;
410         }
411
412         __update_runtime_status(dev, RPM_SUSPENDING);
413
414         if (dev->pm_domain)
415                 callback = dev->pm_domain->ops.runtime_suspend;
416         else if (dev->type && dev->type->pm)
417                 callback = dev->type->pm->runtime_suspend;
418         else if (dev->class && dev->class->pm)
419                 callback = dev->class->pm->runtime_suspend;
420         else if (dev->bus && dev->bus->pm)
421                 callback = dev->bus->pm->runtime_suspend;
422         else
423                 callback = NULL;
424
425         if (!callback && dev->driver && dev->driver->pm)
426                 callback = dev->driver->pm->runtime_suspend;
427
428         retval = rpm_callback(callback, dev);
429         if (retval)
430                 goto fail;
431
432  no_callback:
433         __update_runtime_status(dev, RPM_SUSPENDED);
434         pm_runtime_deactivate_timer(dev);
435
436         if (dev->parent) {
437                 parent = dev->parent;
438                 atomic_add_unless(&parent->power.child_count, -1, 0);
439         }
440         wake_up_all(&dev->power.wait_queue);
441
442         if (dev->power.deferred_resume) {
443                 rpm_resume(dev, 0);
444                 retval = -EAGAIN;
445                 goto out;
446         }
447
448         /* Maybe the parent is now able to suspend. */
449         if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
450                 spin_unlock(&dev->power.lock);
451
452                 spin_lock(&parent->power.lock);
453                 rpm_idle(parent, RPM_ASYNC);
454                 spin_unlock(&parent->power.lock);
455
456                 spin_lock(&dev->power.lock);
457         }
458
459  out:
460         trace_rpm_return_int(dev, _THIS_IP_, retval);
461
462         return retval;
463
464  fail:
465         __update_runtime_status(dev, RPM_ACTIVE);
466         dev->power.deferred_resume = false;
467         wake_up_all(&dev->power.wait_queue);
468
469         if (retval == -EAGAIN || retval == -EBUSY) {
470                 dev->power.runtime_error = 0;
471
472                 /*
473                  * If the callback routine failed an autosuspend, and
474                  * if the last_busy time has been updated so that there
475                  * is a new autosuspend expiration time, automatically
476                  * reschedule another autosuspend.
477                  */
478                 if ((rpmflags & RPM_AUTO) &&
479                     pm_runtime_autosuspend_expiration(dev) != 0)
480                         goto repeat;
481         } else {
482                 pm_runtime_cancel_pending(dev);
483         }
484         goto out;
485 }
486
487 /**
488  * rpm_resume - Carry out runtime resume of given device.
489  * @dev: Device to resume.
490  * @rpmflags: Flag bits.
491  *
492  * Check if the device's runtime PM status allows it to be resumed.  Cancel
493  * any scheduled or pending requests.  If another resume has been started
494  * earlier, either return immediately or wait for it to finish, depending on the
495  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
496  * parallel with this function, either tell the other process to resume after
497  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
498  * flag is set then queue a resume request; otherwise run the
499  * ->runtime_resume() callback directly.  Queue an idle notification for the
500  * device if the resume succeeded.
501  *
502  * This function must be called under dev->power.lock with interrupts disabled.
503  */
504 static int rpm_resume(struct device *dev, int rpmflags)
505         __releases(&dev->power.lock) __acquires(&dev->power.lock)
506 {
507         int (*callback)(struct device *);
508         struct device *parent = NULL;
509         int retval = 0;
510
511         trace_rpm_resume(dev, rpmflags);
512
513  repeat:
514         if (dev->power.runtime_error)
515                 retval = -EINVAL;
516         else if (dev->power.disable_depth > 0)
517                 retval = -EACCES;
518         if (retval)
519                 goto out;
520
521         /*
522          * Other scheduled or pending requests need to be canceled.  Small
523          * optimization: If an autosuspend timer is running, leave it running
524          * rather than cancelling it now only to restart it again in the near
525          * future.
526          */
527         dev->power.request = RPM_REQ_NONE;
528         if (!dev->power.timer_autosuspends)
529                 pm_runtime_deactivate_timer(dev);
530
531         if (dev->power.runtime_status == RPM_ACTIVE) {
532                 retval = 1;
533                 goto out;
534         }
535
536         if (dev->power.runtime_status == RPM_RESUMING
537             || dev->power.runtime_status == RPM_SUSPENDING) {
538                 DEFINE_WAIT(wait);
539
540                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
541                         if (dev->power.runtime_status == RPM_SUSPENDING)
542                                 dev->power.deferred_resume = true;
543                         else
544                                 retval = -EINPROGRESS;
545                         goto out;
546                 }
547
548                 if (dev->power.irq_safe) {
549                         spin_unlock(&dev->power.lock);
550
551                         cpu_relax();
552
553                         spin_lock(&dev->power.lock);
554                         goto repeat;
555                 }
556
557                 /* Wait for the operation carried out in parallel with us. */
558                 for (;;) {
559                         prepare_to_wait(&dev->power.wait_queue, &wait,
560                                         TASK_UNINTERRUPTIBLE);
561                         if (dev->power.runtime_status != RPM_RESUMING
562                             && dev->power.runtime_status != RPM_SUSPENDING)
563                                 break;
564
565                         spin_unlock_irq(&dev->power.lock);
566
567                         schedule();
568
569                         spin_lock_irq(&dev->power.lock);
570                 }
571                 finish_wait(&dev->power.wait_queue, &wait);
572                 goto repeat;
573         }
574
575         /*
576          * See if we can skip waking up the parent.  This is safe only if
577          * power.no_callbacks is set, because otherwise we don't know whether
578          * the resume will actually succeed.
579          */
580         if (dev->power.no_callbacks && !parent && dev->parent) {
581                 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
582                 if (dev->parent->power.disable_depth > 0
583                     || dev->parent->power.ignore_children
584                     || dev->parent->power.runtime_status == RPM_ACTIVE) {
585                         atomic_inc(&dev->parent->power.child_count);
586                         spin_unlock(&dev->parent->power.lock);
587                         goto no_callback;       /* Assume success. */
588                 }
589                 spin_unlock(&dev->parent->power.lock);
590         }
591
592         /* Carry out an asynchronous or a synchronous resume. */
593         if (rpmflags & RPM_ASYNC) {
594                 dev->power.request = RPM_REQ_RESUME;
595                 if (!dev->power.request_pending) {
596                         dev->power.request_pending = true;
597                         queue_work(pm_wq, &dev->power.work);
598                 }
599                 retval = 0;
600                 goto out;
601         }
602
603         if (!parent && dev->parent) {
604                 /*
605                  * Increment the parent's usage counter and resume it if
606                  * necessary.  Not needed if dev is irq-safe; then the
607                  * parent is permanently resumed.
608                  */
609                 parent = dev->parent;
610                 if (dev->power.irq_safe)
611                         goto skip_parent;
612                 spin_unlock(&dev->power.lock);
613
614                 pm_runtime_get_noresume(parent);
615
616                 spin_lock(&parent->power.lock);
617                 /*
618                  * We can resume if the parent's runtime PM is disabled or it
619                  * is set to ignore children.
620                  */
621                 if (!parent->power.disable_depth
622                     && !parent->power.ignore_children) {
623                         rpm_resume(parent, 0);
624                         if (parent->power.runtime_status != RPM_ACTIVE)
625                                 retval = -EBUSY;
626                 }
627                 spin_unlock(&parent->power.lock);
628
629                 spin_lock(&dev->power.lock);
630                 if (retval)
631                         goto out;
632                 goto repeat;
633         }
634  skip_parent:
635
636         if (dev->power.no_callbacks)
637                 goto no_callback;       /* Assume success. */
638
639         __update_runtime_status(dev, RPM_RESUMING);
640
641         if (dev->pm_domain)
642                 callback = dev->pm_domain->ops.runtime_resume;
643         else if (dev->type && dev->type->pm)
644                 callback = dev->type->pm->runtime_resume;
645         else if (dev->class && dev->class->pm)
646                 callback = dev->class->pm->runtime_resume;
647         else if (dev->bus && dev->bus->pm)
648                 callback = dev->bus->pm->runtime_resume;
649         else
650                 callback = NULL;
651
652         if (!callback && dev->driver && dev->driver->pm)
653                 callback = dev->driver->pm->runtime_resume;
654
655         retval = rpm_callback(callback, dev);
656         if (retval) {
657                 __update_runtime_status(dev, RPM_SUSPENDED);
658                 pm_runtime_cancel_pending(dev);
659         } else {
660  no_callback:
661                 __update_runtime_status(dev, RPM_ACTIVE);
662                 if (parent)
663                         atomic_inc(&parent->power.child_count);
664         }
665         wake_up_all(&dev->power.wait_queue);
666
667         if (!retval)
668                 rpm_idle(dev, RPM_ASYNC);
669
670  out:
671         if (parent && !dev->power.irq_safe) {
672                 spin_unlock_irq(&dev->power.lock);
673
674                 pm_runtime_put(parent);
675
676                 spin_lock_irq(&dev->power.lock);
677         }
678
679         trace_rpm_return_int(dev, _THIS_IP_, retval);
680
681         return retval;
682 }
683
684 /**
685  * pm_runtime_work - Universal runtime PM work function.
686  * @work: Work structure used for scheduling the execution of this function.
687  *
688  * Use @work to get the device object the work is to be done for, determine what
689  * is to be done and execute the appropriate runtime PM function.
690  */
691 static void pm_runtime_work(struct work_struct *work)
692 {
693         struct device *dev = container_of(work, struct device, power.work);
694         enum rpm_request req;
695
696         spin_lock_irq(&dev->power.lock);
697
698         if (!dev->power.request_pending)
699                 goto out;
700
701         req = dev->power.request;
702         dev->power.request = RPM_REQ_NONE;
703         dev->power.request_pending = false;
704
705         switch (req) {
706         case RPM_REQ_NONE:
707                 break;
708         case RPM_REQ_IDLE:
709                 rpm_idle(dev, RPM_NOWAIT);
710                 break;
711         case RPM_REQ_SUSPEND:
712                 rpm_suspend(dev, RPM_NOWAIT);
713                 break;
714         case RPM_REQ_AUTOSUSPEND:
715                 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
716                 break;
717         case RPM_REQ_RESUME:
718                 rpm_resume(dev, RPM_NOWAIT);
719                 break;
720         }
721
722  out:
723         spin_unlock_irq(&dev->power.lock);
724 }
725
726 /**
727  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
728  * @data: Device pointer passed by pm_schedule_suspend().
729  *
730  * Check if the time is right and queue a suspend request.
731  */
732 static void pm_suspend_timer_fn(unsigned long data)
733 {
734         struct device *dev = (struct device *)data;
735         unsigned long flags;
736         unsigned long expires;
737
738         spin_lock_irqsave(&dev->power.lock, flags);
739
740         expires = dev->power.timer_expires;
741         /* If 'expire' is after 'jiffies' we've been called too early. */
742         if (expires > 0 && !time_after(expires, jiffies)) {
743                 dev->power.timer_expires = 0;
744                 rpm_suspend(dev, dev->power.timer_autosuspends ?
745                     (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
746         }
747
748         spin_unlock_irqrestore(&dev->power.lock, flags);
749 }
750
751 /**
752  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
753  * @dev: Device to suspend.
754  * @delay: Time to wait before submitting a suspend request, in milliseconds.
755  */
756 int pm_schedule_suspend(struct device *dev, unsigned int delay)
757 {
758         unsigned long flags;
759         int retval;
760
761         spin_lock_irqsave(&dev->power.lock, flags);
762
763         if (!delay) {
764                 retval = rpm_suspend(dev, RPM_ASYNC);
765                 goto out;
766         }
767
768         retval = rpm_check_suspend_allowed(dev);
769         if (retval)
770                 goto out;
771
772         /* Other scheduled or pending requests need to be canceled. */
773         pm_runtime_cancel_pending(dev);
774
775         dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
776         dev->power.timer_expires += !dev->power.timer_expires;
777         dev->power.timer_autosuspends = 0;
778         mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
779
780  out:
781         spin_unlock_irqrestore(&dev->power.lock, flags);
782
783         return retval;
784 }
785 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
786
787 /**
788  * __pm_runtime_idle - Entry point for runtime idle operations.
789  * @dev: Device to send idle notification for.
790  * @rpmflags: Flag bits.
791  *
792  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
793  * return immediately if it is larger than zero.  Then carry out an idle
794  * notification, either synchronous or asynchronous.
795  *
796  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
797  * or if pm_runtime_irq_safe() has been called.
798  */
799 int __pm_runtime_idle(struct device *dev, int rpmflags)
800 {
801         unsigned long flags;
802         int retval;
803
804         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
805
806         if (rpmflags & RPM_GET_PUT) {
807                 if (!atomic_dec_and_test(&dev->power.usage_count))
808                         return 0;
809         }
810
811         spin_lock_irqsave(&dev->power.lock, flags);
812         retval = rpm_idle(dev, rpmflags);
813         spin_unlock_irqrestore(&dev->power.lock, flags);
814
815         return retval;
816 }
817 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
818
819 /**
820  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
821  * @dev: Device to suspend.
822  * @rpmflags: Flag bits.
823  *
824  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
825  * return immediately if it is larger than zero.  Then carry out a suspend,
826  * either synchronous or asynchronous.
827  *
828  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
829  * or if pm_runtime_irq_safe() has been called.
830  */
831 int __pm_runtime_suspend(struct device *dev, int rpmflags)
832 {
833         unsigned long flags;
834         int retval;
835
836         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
837
838         if (rpmflags & RPM_GET_PUT) {
839                 if (!atomic_dec_and_test(&dev->power.usage_count))
840                         return 0;
841         }
842
843         spin_lock_irqsave(&dev->power.lock, flags);
844         retval = rpm_suspend(dev, rpmflags);
845         spin_unlock_irqrestore(&dev->power.lock, flags);
846
847         return retval;
848 }
849 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
850
851 /**
852  * __pm_runtime_resume - Entry point for runtime resume operations.
853  * @dev: Device to resume.
854  * @rpmflags: Flag bits.
855  *
856  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
857  * carry out a resume, either synchronous or asynchronous.
858  *
859  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
860  * or if pm_runtime_irq_safe() has been called.
861  */
862 int __pm_runtime_resume(struct device *dev, int rpmflags)
863 {
864         unsigned long flags;
865         int retval;
866
867         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
868
869         if (rpmflags & RPM_GET_PUT)
870                 atomic_inc(&dev->power.usage_count);
871
872         spin_lock_irqsave(&dev->power.lock, flags);
873         retval = rpm_resume(dev, rpmflags);
874         spin_unlock_irqrestore(&dev->power.lock, flags);
875
876         return retval;
877 }
878 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
879
880 /**
881  * __pm_runtime_set_status - Set runtime PM status of a device.
882  * @dev: Device to handle.
883  * @status: New runtime PM status of the device.
884  *
885  * If runtime PM of the device is disabled or its power.runtime_error field is
886  * different from zero, the status may be changed either to RPM_ACTIVE, or to
887  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
888  * However, if the device has a parent and the parent is not active, and the
889  * parent's power.ignore_children flag is unset, the device's status cannot be
890  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
891  *
892  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
893  * and the device parent's counter of unsuspended children is modified to
894  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
895  * notification request for the parent is submitted.
896  */
897 int __pm_runtime_set_status(struct device *dev, unsigned int status)
898 {
899         struct device *parent = dev->parent;
900         unsigned long flags;
901         bool notify_parent = false;
902         int error = 0;
903
904         if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
905                 return -EINVAL;
906
907         spin_lock_irqsave(&dev->power.lock, flags);
908
909         if (!dev->power.runtime_error && !dev->power.disable_depth) {
910                 error = -EAGAIN;
911                 goto out;
912         }
913
914         if (dev->power.runtime_status == status)
915                 goto out_set;
916
917         if (status == RPM_SUSPENDED) {
918                 /* It always is possible to set the status to 'suspended'. */
919                 if (parent) {
920                         atomic_add_unless(&parent->power.child_count, -1, 0);
921                         notify_parent = !parent->power.ignore_children;
922                 }
923                 goto out_set;
924         }
925
926         if (parent) {
927                 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
928
929                 /*
930                  * It is invalid to put an active child under a parent that is
931                  * not active, has runtime PM enabled and the
932                  * 'power.ignore_children' flag unset.
933                  */
934                 if (!parent->power.disable_depth
935                     && !parent->power.ignore_children
936                     && parent->power.runtime_status != RPM_ACTIVE)
937                         error = -EBUSY;
938                 else if (dev->power.runtime_status == RPM_SUSPENDED)
939                         atomic_inc(&parent->power.child_count);
940
941                 spin_unlock(&parent->power.lock);
942
943                 if (error)
944                         goto out;
945         }
946
947  out_set:
948         __update_runtime_status(dev, status);
949         dev->power.runtime_error = 0;
950  out:
951         spin_unlock_irqrestore(&dev->power.lock, flags);
952
953         if (notify_parent)
954                 pm_request_idle(parent);
955
956         return error;
957 }
958 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
959
960 /**
961  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
962  * @dev: Device to handle.
963  *
964  * Flush all pending requests for the device from pm_wq and wait for all
965  * runtime PM operations involving the device in progress to complete.
966  *
967  * Should be called under dev->power.lock with interrupts disabled.
968  */
969 static void __pm_runtime_barrier(struct device *dev)
970 {
971         pm_runtime_deactivate_timer(dev);
972
973         if (dev->power.request_pending) {
974                 dev->power.request = RPM_REQ_NONE;
975                 spin_unlock_irq(&dev->power.lock);
976
977                 cancel_work_sync(&dev->power.work);
978
979                 spin_lock_irq(&dev->power.lock);
980                 dev->power.request_pending = false;
981         }
982
983         if (dev->power.runtime_status == RPM_SUSPENDING
984             || dev->power.runtime_status == RPM_RESUMING
985             || dev->power.idle_notification) {
986                 DEFINE_WAIT(wait);
987
988                 /* Suspend, wake-up or idle notification in progress. */
989                 for (;;) {
990                         prepare_to_wait(&dev->power.wait_queue, &wait,
991                                         TASK_UNINTERRUPTIBLE);
992                         if (dev->power.runtime_status != RPM_SUSPENDING
993                             && dev->power.runtime_status != RPM_RESUMING
994                             && !dev->power.idle_notification)
995                                 break;
996                         spin_unlock_irq(&dev->power.lock);
997
998                         schedule();
999
1000                         spin_lock_irq(&dev->power.lock);
1001                 }
1002                 finish_wait(&dev->power.wait_queue, &wait);
1003         }
1004 }
1005
1006 /**
1007  * pm_runtime_barrier - Flush pending requests and wait for completions.
1008  * @dev: Device to handle.
1009  *
1010  * Prevent the device from being suspended by incrementing its usage counter and
1011  * if there's a pending resume request for the device, wake the device up.
1012  * Next, make sure that all pending requests for the device have been flushed
1013  * from pm_wq and wait for all runtime PM operations involving the device in
1014  * progress to complete.
1015  *
1016  * Return value:
1017  * 1, if there was a resume request pending and the device had to be woken up,
1018  * 0, otherwise
1019  */
1020 int pm_runtime_barrier(struct device *dev)
1021 {
1022         int retval = 0;
1023
1024         pm_runtime_get_noresume(dev);
1025         spin_lock_irq(&dev->power.lock);
1026
1027         if (dev->power.request_pending
1028             && dev->power.request == RPM_REQ_RESUME) {
1029                 rpm_resume(dev, 0);
1030                 retval = 1;
1031         }
1032
1033         __pm_runtime_barrier(dev);
1034
1035         spin_unlock_irq(&dev->power.lock);
1036         pm_runtime_put_noidle(dev);
1037
1038         return retval;
1039 }
1040 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1041
1042 /**
1043  * __pm_runtime_disable - Disable runtime PM of a device.
1044  * @dev: Device to handle.
1045  * @check_resume: If set, check if there's a resume request for the device.
1046  *
1047  * Increment power.disable_depth for the device and if was zero previously,
1048  * cancel all pending runtime PM requests for the device and wait for all
1049  * operations in progress to complete.  The device can be either active or
1050  * suspended after its runtime PM has been disabled.
1051  *
1052  * If @check_resume is set and there's a resume request pending when
1053  * __pm_runtime_disable() is called and power.disable_depth is zero, the
1054  * function will wake up the device before disabling its runtime PM.
1055  */
1056 void __pm_runtime_disable(struct device *dev, bool check_resume)
1057 {
1058         spin_lock_irq(&dev->power.lock);
1059
1060         if (dev->power.disable_depth > 0) {
1061                 dev->power.disable_depth++;
1062                 goto out;
1063         }
1064
1065         /*
1066          * Wake up the device if there's a resume request pending, because that
1067          * means there probably is some I/O to process and disabling runtime PM
1068          * shouldn't prevent the device from processing the I/O.
1069          */
1070         if (check_resume && dev->power.request_pending
1071             && dev->power.request == RPM_REQ_RESUME) {
1072                 /*
1073                  * Prevent suspends and idle notifications from being carried
1074                  * out after we have woken up the device.
1075                  */
1076                 pm_runtime_get_noresume(dev);
1077
1078                 rpm_resume(dev, 0);
1079
1080                 pm_runtime_put_noidle(dev);
1081         }
1082
1083         if (!dev->power.disable_depth++)
1084                 __pm_runtime_barrier(dev);
1085
1086  out:
1087         spin_unlock_irq(&dev->power.lock);
1088 }
1089 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1090
1091 /**
1092  * pm_runtime_enable - Enable runtime PM of a device.
1093  * @dev: Device to handle.
1094  */
1095 void pm_runtime_enable(struct device *dev)
1096 {
1097         unsigned long flags;
1098
1099         spin_lock_irqsave(&dev->power.lock, flags);
1100
1101         if (dev->power.disable_depth > 0)
1102                 dev->power.disable_depth--;
1103         else
1104                 dev_warn(dev, "Unbalanced %s!\n", __func__);
1105
1106         spin_unlock_irqrestore(&dev->power.lock, flags);
1107 }
1108 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1109
1110 /**
1111  * pm_runtime_forbid - Block runtime PM of a device.
1112  * @dev: Device to handle.
1113  *
1114  * Increase the device's usage count and clear its power.runtime_auto flag,
1115  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1116  * for it.
1117  */
1118 void pm_runtime_forbid(struct device *dev)
1119 {
1120         spin_lock_irq(&dev->power.lock);
1121         if (!dev->power.runtime_auto)
1122                 goto out;
1123
1124         dev->power.runtime_auto = false;
1125         atomic_inc(&dev->power.usage_count);
1126         rpm_resume(dev, 0);
1127
1128  out:
1129         spin_unlock_irq(&dev->power.lock);
1130 }
1131 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1132
1133 /**
1134  * pm_runtime_allow - Unblock runtime PM of a device.
1135  * @dev: Device to handle.
1136  *
1137  * Decrease the device's usage count and set its power.runtime_auto flag.
1138  */
1139 void pm_runtime_allow(struct device *dev)
1140 {
1141         spin_lock_irq(&dev->power.lock);
1142         if (dev->power.runtime_auto)
1143                 goto out;
1144
1145         dev->power.runtime_auto = true;
1146         if (atomic_dec_and_test(&dev->power.usage_count))
1147                 rpm_idle(dev, RPM_AUTO);
1148
1149  out:
1150         spin_unlock_irq(&dev->power.lock);
1151 }
1152 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1153
1154 /**
1155  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1156  * @dev: Device to handle.
1157  *
1158  * Set the power.no_callbacks flag, which tells the PM core that this
1159  * device is power-managed through its parent and has no runtime PM
1160  * callbacks of its own.  The runtime sysfs attributes will be removed.
1161  */
1162 void pm_runtime_no_callbacks(struct device *dev)
1163 {
1164         spin_lock_irq(&dev->power.lock);
1165         dev->power.no_callbacks = 1;
1166         spin_unlock_irq(&dev->power.lock);
1167         if (device_is_registered(dev))
1168                 rpm_sysfs_remove(dev);
1169 }
1170 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1171
1172 /**
1173  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1174  * @dev: Device to handle
1175  *
1176  * Set the power.irq_safe flag, which tells the PM core that the
1177  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1178  * always be invoked with the spinlock held and interrupts disabled.  It also
1179  * causes the parent's usage counter to be permanently incremented, preventing
1180  * the parent from runtime suspending -- otherwise an irq-safe child might have
1181  * to wait for a non-irq-safe parent.
1182  */
1183 void pm_runtime_irq_safe(struct device *dev)
1184 {
1185         if (dev->parent)
1186                 pm_runtime_get_sync(dev->parent);
1187         spin_lock_irq(&dev->power.lock);
1188         dev->power.irq_safe = 1;
1189         spin_unlock_irq(&dev->power.lock);
1190 }
1191 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1192
1193 /**
1194  * update_autosuspend - Handle a change to a device's autosuspend settings.
1195  * @dev: Device to handle.
1196  * @old_delay: The former autosuspend_delay value.
1197  * @old_use: The former use_autosuspend value.
1198  *
1199  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1200  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1201  *
1202  * This function must be called under dev->power.lock with interrupts disabled.
1203  */
1204 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1205 {
1206         int delay = dev->power.autosuspend_delay;
1207
1208         /* Should runtime suspend be prevented now? */
1209         if (dev->power.use_autosuspend && delay < 0) {
1210
1211                 /* If it used to be allowed then prevent it. */
1212                 if (!old_use || old_delay >= 0) {
1213                         atomic_inc(&dev->power.usage_count);
1214                         rpm_resume(dev, 0);
1215                 }
1216         }
1217
1218         /* Runtime suspend should be allowed now. */
1219         else {
1220
1221                 /* If it used to be prevented then allow it. */
1222                 if (old_use && old_delay < 0)
1223                         atomic_dec(&dev->power.usage_count);
1224
1225                 /* Maybe we can autosuspend now. */
1226                 rpm_idle(dev, RPM_AUTO);
1227         }
1228 }
1229
1230 /**
1231  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1232  * @dev: Device to handle.
1233  * @delay: Value of the new delay in milliseconds.
1234  *
1235  * Set the device's power.autosuspend_delay value.  If it changes to negative
1236  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1237  * changes the other way, allow runtime suspends.
1238  */
1239 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1240 {
1241         int old_delay, old_use;
1242
1243         spin_lock_irq(&dev->power.lock);
1244         old_delay = dev->power.autosuspend_delay;
1245         old_use = dev->power.use_autosuspend;
1246         dev->power.autosuspend_delay = delay;
1247         update_autosuspend(dev, old_delay, old_use);
1248         spin_unlock_irq(&dev->power.lock);
1249 }
1250 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1251
1252 /**
1253  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1254  * @dev: Device to handle.
1255  * @use: New value for use_autosuspend.
1256  *
1257  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1258  * suspends as needed.
1259  */
1260 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1261 {
1262         int old_delay, old_use;
1263
1264         spin_lock_irq(&dev->power.lock);
1265         old_delay = dev->power.autosuspend_delay;
1266         old_use = dev->power.use_autosuspend;
1267         dev->power.use_autosuspend = use;
1268         update_autosuspend(dev, old_delay, old_use);
1269         spin_unlock_irq(&dev->power.lock);
1270 }
1271 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1272
1273 /**
1274  * pm_runtime_init - Initialize runtime PM fields in given device object.
1275  * @dev: Device object to initialize.
1276  */
1277 void pm_runtime_init(struct device *dev)
1278 {
1279         dev->power.runtime_status = RPM_SUSPENDED;
1280         dev->power.idle_notification = false;
1281
1282         dev->power.disable_depth = 1;
1283         atomic_set(&dev->power.usage_count, 0);
1284
1285         dev->power.runtime_error = 0;
1286
1287         atomic_set(&dev->power.child_count, 0);
1288         pm_suspend_ignore_children(dev, false);
1289         dev->power.runtime_auto = true;
1290
1291         dev->power.request_pending = false;
1292         dev->power.request = RPM_REQ_NONE;
1293         dev->power.deferred_resume = false;
1294         dev->power.accounting_timestamp = jiffies;
1295         INIT_WORK(&dev->power.work, pm_runtime_work);
1296
1297         dev->power.timer_expires = 0;
1298         setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1299                         (unsigned long)dev);
1300
1301         init_waitqueue_head(&dev->power.wait_queue);
1302 }
1303
1304 /**
1305  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1306  * @dev: Device object being removed from device hierarchy.
1307  */
1308 void pm_runtime_remove(struct device *dev)
1309 {
1310         __pm_runtime_disable(dev, false);
1311
1312         /* Change the status back to 'suspended' to match the initial status. */
1313         if (dev->power.runtime_status == RPM_ACTIVE)
1314                 pm_runtime_set_suspended(dev);
1315         if (dev->power.irq_safe && dev->parent)
1316                 pm_runtime_put_sync(dev->parent);
1317 }