977db40378b07e59fbb9943aacb437f9e47bc438
[muen/linux.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/mm.h>
11 #include <linux/ktime.h>
12 #include <linux/hrtimer.h>
13 #include <linux/export.h>
14 #include <linux/pm_runtime.h>
15 #include <linux/pm_wakeirq.h>
16 #include <trace/events/rpm.h>
17
18 #include "../base.h"
19 #include "power.h"
20
21 typedef int (*pm_callback_t)(struct device *);
22
23 static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
24 {
25         pm_callback_t cb;
26         const struct dev_pm_ops *ops;
27
28         if (dev->pm_domain)
29                 ops = &dev->pm_domain->ops;
30         else if (dev->type && dev->type->pm)
31                 ops = dev->type->pm;
32         else if (dev->class && dev->class->pm)
33                 ops = dev->class->pm;
34         else if (dev->bus && dev->bus->pm)
35                 ops = dev->bus->pm;
36         else
37                 ops = NULL;
38
39         if (ops)
40                 cb = *(pm_callback_t *)((void *)ops + cb_offset);
41         else
42                 cb = NULL;
43
44         if (!cb && dev->driver && dev->driver->pm)
45                 cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
46
47         return cb;
48 }
49
50 #define RPM_GET_CALLBACK(dev, callback) \
51                 __rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
52
53 static int rpm_resume(struct device *dev, int rpmflags);
54 static int rpm_suspend(struct device *dev, int rpmflags);
55
56 /**
57  * update_pm_runtime_accounting - Update the time accounting of power states
58  * @dev: Device to update the accounting for
59  *
60  * In order to be able to have time accounting of the various power states
61  * (as used by programs such as PowerTOP to show the effectiveness of runtime
62  * PM), we need to track the time spent in each state.
63  * update_pm_runtime_accounting must be called each time before the
64  * runtime_status field is updated, to account the time in the old state
65  * correctly.
66  */
67 static void update_pm_runtime_accounting(struct device *dev)
68 {
69         u64 now, last, delta;
70
71         if (dev->power.disable_depth > 0)
72                 return;
73
74         last = dev->power.accounting_timestamp;
75
76         now = ktime_get_mono_fast_ns();
77         dev->power.accounting_timestamp = now;
78
79         /*
80          * Because ktime_get_mono_fast_ns() is not monotonic during
81          * timekeeping updates, ensure that 'now' is after the last saved
82          * timesptamp.
83          */
84         if (now < last)
85                 return;
86
87         delta = now - last;
88
89         if (dev->power.runtime_status == RPM_SUSPENDED)
90                 dev->power.suspended_time += delta;
91         else
92                 dev->power.active_time += delta;
93 }
94
95 static void __update_runtime_status(struct device *dev, enum rpm_status status)
96 {
97         update_pm_runtime_accounting(dev);
98         dev->power.runtime_status = status;
99 }
100
101 static u64 rpm_get_accounted_time(struct device *dev, bool suspended)
102 {
103         u64 time;
104         unsigned long flags;
105
106         spin_lock_irqsave(&dev->power.lock, flags);
107
108         update_pm_runtime_accounting(dev);
109         time = suspended ? dev->power.suspended_time : dev->power.active_time;
110
111         spin_unlock_irqrestore(&dev->power.lock, flags);
112
113         return time;
114 }
115
116 u64 pm_runtime_active_time(struct device *dev)
117 {
118         return rpm_get_accounted_time(dev, false);
119 }
120
121 u64 pm_runtime_suspended_time(struct device *dev)
122 {
123         return rpm_get_accounted_time(dev, true);
124 }
125 EXPORT_SYMBOL_GPL(pm_runtime_suspended_time);
126
127 /**
128  * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
129  * @dev: Device to handle.
130  */
131 static void pm_runtime_deactivate_timer(struct device *dev)
132 {
133         if (dev->power.timer_expires > 0) {
134                 hrtimer_try_to_cancel(&dev->power.suspend_timer);
135                 dev->power.timer_expires = 0;
136         }
137 }
138
139 /**
140  * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
141  * @dev: Device to handle.
142  */
143 static void pm_runtime_cancel_pending(struct device *dev)
144 {
145         pm_runtime_deactivate_timer(dev);
146         /*
147          * In case there's a request pending, make sure its work function will
148          * return without doing anything.
149          */
150         dev->power.request = RPM_REQ_NONE;
151 }
152
153 /*
154  * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
155  * @dev: Device to handle.
156  *
157  * Compute the autosuspend-delay expiration time based on the device's
158  * power.last_busy time.  If the delay has already expired or is disabled
159  * (negative) or the power.use_autosuspend flag isn't set, return 0.
160  * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero).
161  *
162  * This function may be called either with or without dev->power.lock held.
163  * Either way it can be racy, since power.last_busy may be updated at any time.
164  */
165 u64 pm_runtime_autosuspend_expiration(struct device *dev)
166 {
167         int autosuspend_delay;
168         u64 expires;
169
170         if (!dev->power.use_autosuspend)
171                 return 0;
172
173         autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay);
174         if (autosuspend_delay < 0)
175                 return 0;
176
177         expires  = READ_ONCE(dev->power.last_busy);
178         expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
179         if (expires > ktime_get_mono_fast_ns())
180                 return expires; /* Expires in the future */
181
182         return 0;
183 }
184 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
185
186 static int dev_memalloc_noio(struct device *dev, void *data)
187 {
188         return dev->power.memalloc_noio;
189 }
190
191 /*
192  * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
193  * @dev: Device to handle.
194  * @enable: True for setting the flag and False for clearing the flag.
195  *
196  * Set the flag for all devices in the path from the device to the
197  * root device in the device tree if @enable is true, otherwise clear
198  * the flag for devices in the path whose siblings don't set the flag.
199  *
200  * The function should only be called by block device, or network
201  * device driver for solving the deadlock problem during runtime
202  * resume/suspend:
203  *
204  *     If memory allocation with GFP_KERNEL is called inside runtime
205  *     resume/suspend callback of any one of its ancestors(or the
206  *     block device itself), the deadlock may be triggered inside the
207  *     memory allocation since it might not complete until the block
208  *     device becomes active and the involed page I/O finishes. The
209  *     situation is pointed out first by Alan Stern. Network device
210  *     are involved in iSCSI kind of situation.
211  *
212  * The lock of dev_hotplug_mutex is held in the function for handling
213  * hotplug race because pm_runtime_set_memalloc_noio() may be called
214  * in async probe().
215  *
216  * The function should be called between device_add() and device_del()
217  * on the affected device(block/network device).
218  */
219 void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
220 {
221         static DEFINE_MUTEX(dev_hotplug_mutex);
222
223         mutex_lock(&dev_hotplug_mutex);
224         for (;;) {
225                 bool enabled;
226
227                 /* hold power lock since bitfield is not SMP-safe. */
228                 spin_lock_irq(&dev->power.lock);
229                 enabled = dev->power.memalloc_noio;
230                 dev->power.memalloc_noio = enable;
231                 spin_unlock_irq(&dev->power.lock);
232
233                 /*
234                  * not need to enable ancestors any more if the device
235                  * has been enabled.
236                  */
237                 if (enabled && enable)
238                         break;
239
240                 dev = dev->parent;
241
242                 /*
243                  * clear flag of the parent device only if all the
244                  * children don't set the flag because ancestor's
245                  * flag was set by any one of the descendants.
246                  */
247                 if (!dev || (!enable &&
248                              device_for_each_child(dev, NULL,
249                                                    dev_memalloc_noio)))
250                         break;
251         }
252         mutex_unlock(&dev_hotplug_mutex);
253 }
254 EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
255
256 /**
257  * rpm_check_suspend_allowed - Test whether a device may be suspended.
258  * @dev: Device to test.
259  */
260 static int rpm_check_suspend_allowed(struct device *dev)
261 {
262         int retval = 0;
263
264         if (dev->power.runtime_error)
265                 retval = -EINVAL;
266         else if (dev->power.disable_depth > 0)
267                 retval = -EACCES;
268         else if (atomic_read(&dev->power.usage_count) > 0)
269                 retval = -EAGAIN;
270         else if (!dev->power.ignore_children &&
271                         atomic_read(&dev->power.child_count))
272                 retval = -EBUSY;
273
274         /* Pending resume requests take precedence over suspends. */
275         else if ((dev->power.deferred_resume
276                         && dev->power.runtime_status == RPM_SUSPENDING)
277             || (dev->power.request_pending
278                         && dev->power.request == RPM_REQ_RESUME))
279                 retval = -EAGAIN;
280         else if (__dev_pm_qos_read_value(dev) == 0)
281                 retval = -EPERM;
282         else if (dev->power.runtime_status == RPM_SUSPENDED)
283                 retval = 1;
284
285         return retval;
286 }
287
288 static int rpm_get_suppliers(struct device *dev)
289 {
290         struct device_link *link;
291
292         list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
293                 int retval;
294
295                 if (!(link->flags & DL_FLAG_PM_RUNTIME) ||
296                     READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND)
297                         continue;
298
299                 retval = pm_runtime_get_sync(link->supplier);
300                 /* Ignore suppliers with disabled runtime PM. */
301                 if (retval < 0 && retval != -EACCES) {
302                         pm_runtime_put_noidle(link->supplier);
303                         return retval;
304                 }
305                 refcount_inc(&link->rpm_active);
306         }
307         return 0;
308 }
309
310 static void rpm_put_suppliers(struct device *dev)
311 {
312         struct device_link *link;
313
314         list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
315                 if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND)
316                         continue;
317
318                 while (refcount_dec_not_one(&link->rpm_active))
319                         pm_runtime_put(link->supplier);
320         }
321 }
322
323 /**
324  * __rpm_callback - Run a given runtime PM callback for a given device.
325  * @cb: Runtime PM callback to run.
326  * @dev: Device to run the callback for.
327  */
328 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
329         __releases(&dev->power.lock) __acquires(&dev->power.lock)
330 {
331         int retval, idx;
332         bool use_links = dev->power.links_count > 0;
333
334         if (dev->power.irq_safe) {
335                 spin_unlock(&dev->power.lock);
336         } else {
337                 spin_unlock_irq(&dev->power.lock);
338
339                 /*
340                  * Resume suppliers if necessary.
341                  *
342                  * The device's runtime PM status cannot change until this
343                  * routine returns, so it is safe to read the status outside of
344                  * the lock.
345                  */
346                 if (use_links && dev->power.runtime_status == RPM_RESUMING) {
347                         idx = device_links_read_lock();
348
349                         retval = rpm_get_suppliers(dev);
350                         if (retval)
351                                 goto fail;
352
353                         device_links_read_unlock(idx);
354                 }
355         }
356
357         retval = cb(dev);
358
359         if (dev->power.irq_safe) {
360                 spin_lock(&dev->power.lock);
361         } else {
362                 /*
363                  * If the device is suspending and the callback has returned
364                  * success, drop the usage counters of the suppliers that have
365                  * been reference counted on its resume.
366                  *
367                  * Do that if resume fails too.
368                  */
369                 if (use_links
370                     && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
371                     || (dev->power.runtime_status == RPM_RESUMING && retval))) {
372                         idx = device_links_read_lock();
373
374  fail:
375                         rpm_put_suppliers(dev);
376
377                         device_links_read_unlock(idx);
378                 }
379
380                 spin_lock_irq(&dev->power.lock);
381         }
382
383         return retval;
384 }
385
386 /**
387  * rpm_idle - Notify device bus type if the device can be suspended.
388  * @dev: Device to notify the bus type about.
389  * @rpmflags: Flag bits.
390  *
391  * Check if the device's runtime PM status allows it to be suspended.  If
392  * another idle notification has been started earlier, return immediately.  If
393  * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
394  * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
395  * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
396  *
397  * This function must be called under dev->power.lock with interrupts disabled.
398  */
399 static int rpm_idle(struct device *dev, int rpmflags)
400 {
401         int (*callback)(struct device *);
402         int retval;
403
404         trace_rpm_idle_rcuidle(dev, rpmflags);
405         retval = rpm_check_suspend_allowed(dev);
406         if (retval < 0)
407                 ;       /* Conditions are wrong. */
408
409         /* Idle notifications are allowed only in the RPM_ACTIVE state. */
410         else if (dev->power.runtime_status != RPM_ACTIVE)
411                 retval = -EAGAIN;
412
413         /*
414          * Any pending request other than an idle notification takes
415          * precedence over us, except that the timer may be running.
416          */
417         else if (dev->power.request_pending &&
418             dev->power.request > RPM_REQ_IDLE)
419                 retval = -EAGAIN;
420
421         /* Act as though RPM_NOWAIT is always set. */
422         else if (dev->power.idle_notification)
423                 retval = -EINPROGRESS;
424         if (retval)
425                 goto out;
426
427         /* Pending requests need to be canceled. */
428         dev->power.request = RPM_REQ_NONE;
429
430         if (dev->power.no_callbacks)
431                 goto out;
432
433         /* Carry out an asynchronous or a synchronous idle notification. */
434         if (rpmflags & RPM_ASYNC) {
435                 dev->power.request = RPM_REQ_IDLE;
436                 if (!dev->power.request_pending) {
437                         dev->power.request_pending = true;
438                         queue_work(pm_wq, &dev->power.work);
439                 }
440                 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
441                 return 0;
442         }
443
444         dev->power.idle_notification = true;
445
446         callback = RPM_GET_CALLBACK(dev, runtime_idle);
447
448         if (callback)
449                 retval = __rpm_callback(callback, dev);
450
451         dev->power.idle_notification = false;
452         wake_up_all(&dev->power.wait_queue);
453
454  out:
455         trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
456         return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
457 }
458
459 /**
460  * rpm_callback - Run a given runtime PM callback for a given device.
461  * @cb: Runtime PM callback to run.
462  * @dev: Device to run the callback for.
463  */
464 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
465 {
466         int retval;
467
468         if (!cb)
469                 return -ENOSYS;
470
471         if (dev->power.memalloc_noio) {
472                 unsigned int noio_flag;
473
474                 /*
475                  * Deadlock might be caused if memory allocation with
476                  * GFP_KERNEL happens inside runtime_suspend and
477                  * runtime_resume callbacks of one block device's
478                  * ancestor or the block device itself. Network
479                  * device might be thought as part of iSCSI block
480                  * device, so network device and its ancestor should
481                  * be marked as memalloc_noio too.
482                  */
483                 noio_flag = memalloc_noio_save();
484                 retval = __rpm_callback(cb, dev);
485                 memalloc_noio_restore(noio_flag);
486         } else {
487                 retval = __rpm_callback(cb, dev);
488         }
489
490         dev->power.runtime_error = retval;
491         return retval != -EACCES ? retval : -EIO;
492 }
493
494 /**
495  * rpm_suspend - Carry out runtime suspend of given device.
496  * @dev: Device to suspend.
497  * @rpmflags: Flag bits.
498  *
499  * Check if the device's runtime PM status allows it to be suspended.
500  * Cancel a pending idle notification, autosuspend or suspend. If
501  * another suspend has been started earlier, either return immediately
502  * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
503  * flags. If the RPM_ASYNC flag is set then queue a suspend request;
504  * otherwise run the ->runtime_suspend() callback directly. When
505  * ->runtime_suspend succeeded, if a deferred resume was requested while
506  * the callback was running then carry it out, otherwise send an idle
507  * notification for its parent (if the suspend succeeded and both
508  * ignore_children of parent->power and irq_safe of dev->power are not set).
509  * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
510  * flag is set and the next autosuspend-delay expiration time is in the
511  * future, schedule another autosuspend attempt.
512  *
513  * This function must be called under dev->power.lock with interrupts disabled.
514  */
515 static int rpm_suspend(struct device *dev, int rpmflags)
516         __releases(&dev->power.lock) __acquires(&dev->power.lock)
517 {
518         int (*callback)(struct device *);
519         struct device *parent = NULL;
520         int retval;
521
522         trace_rpm_suspend_rcuidle(dev, rpmflags);
523
524  repeat:
525         retval = rpm_check_suspend_allowed(dev);
526
527         if (retval < 0)
528                 ;       /* Conditions are wrong. */
529
530         /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
531         else if (dev->power.runtime_status == RPM_RESUMING &&
532             !(rpmflags & RPM_ASYNC))
533                 retval = -EAGAIN;
534         if (retval)
535                 goto out;
536
537         /* If the autosuspend_delay time hasn't expired yet, reschedule. */
538         if ((rpmflags & RPM_AUTO)
539             && dev->power.runtime_status != RPM_SUSPENDING) {
540                 u64 expires = pm_runtime_autosuspend_expiration(dev);
541
542                 if (expires != 0) {
543                         /* Pending requests need to be canceled. */
544                         dev->power.request = RPM_REQ_NONE;
545
546                         /*
547                          * Optimization: If the timer is already running and is
548                          * set to expire at or before the autosuspend delay,
549                          * avoid the overhead of resetting it.  Just let it
550                          * expire; pm_suspend_timer_fn() will take care of the
551                          * rest.
552                          */
553                         if (!(dev->power.timer_expires &&
554                                         dev->power.timer_expires <= expires)) {
555                                 /*
556                                  * We add a slack of 25% to gather wakeups
557                                  * without sacrificing the granularity.
558                                  */
559                                 u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) *
560                                                     (NSEC_PER_MSEC >> 2);
561
562                                 dev->power.timer_expires = expires;
563                                 hrtimer_start_range_ns(&dev->power.suspend_timer,
564                                                 ns_to_ktime(expires),
565                                                 slack,
566                                                 HRTIMER_MODE_ABS);
567                         }
568                         dev->power.timer_autosuspends = 1;
569                         goto out;
570                 }
571         }
572
573         /* Other scheduled or pending requests need to be canceled. */
574         pm_runtime_cancel_pending(dev);
575
576         if (dev->power.runtime_status == RPM_SUSPENDING) {
577                 DEFINE_WAIT(wait);
578
579                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
580                         retval = -EINPROGRESS;
581                         goto out;
582                 }
583
584                 if (dev->power.irq_safe) {
585                         spin_unlock(&dev->power.lock);
586
587                         cpu_relax();
588
589                         spin_lock(&dev->power.lock);
590                         goto repeat;
591                 }
592
593                 /* Wait for the other suspend running in parallel with us. */
594                 for (;;) {
595                         prepare_to_wait(&dev->power.wait_queue, &wait,
596                                         TASK_UNINTERRUPTIBLE);
597                         if (dev->power.runtime_status != RPM_SUSPENDING)
598                                 break;
599
600                         spin_unlock_irq(&dev->power.lock);
601
602                         schedule();
603
604                         spin_lock_irq(&dev->power.lock);
605                 }
606                 finish_wait(&dev->power.wait_queue, &wait);
607                 goto repeat;
608         }
609
610         if (dev->power.no_callbacks)
611                 goto no_callback;       /* Assume success. */
612
613         /* Carry out an asynchronous or a synchronous suspend. */
614         if (rpmflags & RPM_ASYNC) {
615                 dev->power.request = (rpmflags & RPM_AUTO) ?
616                     RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
617                 if (!dev->power.request_pending) {
618                         dev->power.request_pending = true;
619                         queue_work(pm_wq, &dev->power.work);
620                 }
621                 goto out;
622         }
623
624         __update_runtime_status(dev, RPM_SUSPENDING);
625
626         callback = RPM_GET_CALLBACK(dev, runtime_suspend);
627
628         dev_pm_enable_wake_irq_check(dev, true);
629         retval = rpm_callback(callback, dev);
630         if (retval)
631                 goto fail;
632
633  no_callback:
634         __update_runtime_status(dev, RPM_SUSPENDED);
635         pm_runtime_deactivate_timer(dev);
636
637         if (dev->parent) {
638                 parent = dev->parent;
639                 atomic_add_unless(&parent->power.child_count, -1, 0);
640         }
641         wake_up_all(&dev->power.wait_queue);
642
643         if (dev->power.deferred_resume) {
644                 dev->power.deferred_resume = false;
645                 rpm_resume(dev, 0);
646                 retval = -EAGAIN;
647                 goto out;
648         }
649
650         /* Maybe the parent is now able to suspend. */
651         if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
652                 spin_unlock(&dev->power.lock);
653
654                 spin_lock(&parent->power.lock);
655                 rpm_idle(parent, RPM_ASYNC);
656                 spin_unlock(&parent->power.lock);
657
658                 spin_lock(&dev->power.lock);
659         }
660
661  out:
662         trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
663
664         return retval;
665
666  fail:
667         dev_pm_disable_wake_irq_check(dev);
668         __update_runtime_status(dev, RPM_ACTIVE);
669         dev->power.deferred_resume = false;
670         wake_up_all(&dev->power.wait_queue);
671
672         if (retval == -EAGAIN || retval == -EBUSY) {
673                 dev->power.runtime_error = 0;
674
675                 /*
676                  * If the callback routine failed an autosuspend, and
677                  * if the last_busy time has been updated so that there
678                  * is a new autosuspend expiration time, automatically
679                  * reschedule another autosuspend.
680                  */
681                 if ((rpmflags & RPM_AUTO) &&
682                     pm_runtime_autosuspend_expiration(dev) != 0)
683                         goto repeat;
684         } else {
685                 pm_runtime_cancel_pending(dev);
686         }
687         goto out;
688 }
689
690 /**
691  * rpm_resume - Carry out runtime resume of given device.
692  * @dev: Device to resume.
693  * @rpmflags: Flag bits.
694  *
695  * Check if the device's runtime PM status allows it to be resumed.  Cancel
696  * any scheduled or pending requests.  If another resume has been started
697  * earlier, either return immediately or wait for it to finish, depending on the
698  * RPM_NOWAIT and RPM_ASYNC flags.  Similarly, if there's a suspend running in
699  * parallel with this function, either tell the other process to resume after
700  * suspending (deferred_resume) or wait for it to finish.  If the RPM_ASYNC
701  * flag is set then queue a resume request; otherwise run the
702  * ->runtime_resume() callback directly.  Queue an idle notification for the
703  * device if the resume succeeded.
704  *
705  * This function must be called under dev->power.lock with interrupts disabled.
706  */
707 static int rpm_resume(struct device *dev, int rpmflags)
708         __releases(&dev->power.lock) __acquires(&dev->power.lock)
709 {
710         int (*callback)(struct device *);
711         struct device *parent = NULL;
712         int retval = 0;
713
714         trace_rpm_resume_rcuidle(dev, rpmflags);
715
716  repeat:
717         if (dev->power.runtime_error)
718                 retval = -EINVAL;
719         else if (dev->power.disable_depth == 1 && dev->power.is_suspended
720             && dev->power.runtime_status == RPM_ACTIVE)
721                 retval = 1;
722         else if (dev->power.disable_depth > 0)
723                 retval = -EACCES;
724         if (retval)
725                 goto out;
726
727         /*
728          * Other scheduled or pending requests need to be canceled.  Small
729          * optimization: If an autosuspend timer is running, leave it running
730          * rather than cancelling it now only to restart it again in the near
731          * future.
732          */
733         dev->power.request = RPM_REQ_NONE;
734         if (!dev->power.timer_autosuspends)
735                 pm_runtime_deactivate_timer(dev);
736
737         if (dev->power.runtime_status == RPM_ACTIVE) {
738                 retval = 1;
739                 goto out;
740         }
741
742         if (dev->power.runtime_status == RPM_RESUMING
743             || dev->power.runtime_status == RPM_SUSPENDING) {
744                 DEFINE_WAIT(wait);
745
746                 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
747                         if (dev->power.runtime_status == RPM_SUSPENDING)
748                                 dev->power.deferred_resume = true;
749                         else
750                                 retval = -EINPROGRESS;
751                         goto out;
752                 }
753
754                 if (dev->power.irq_safe) {
755                         spin_unlock(&dev->power.lock);
756
757                         cpu_relax();
758
759                         spin_lock(&dev->power.lock);
760                         goto repeat;
761                 }
762
763                 /* Wait for the operation carried out in parallel with us. */
764                 for (;;) {
765                         prepare_to_wait(&dev->power.wait_queue, &wait,
766                                         TASK_UNINTERRUPTIBLE);
767                         if (dev->power.runtime_status != RPM_RESUMING
768                             && dev->power.runtime_status != RPM_SUSPENDING)
769                                 break;
770
771                         spin_unlock_irq(&dev->power.lock);
772
773                         schedule();
774
775                         spin_lock_irq(&dev->power.lock);
776                 }
777                 finish_wait(&dev->power.wait_queue, &wait);
778                 goto repeat;
779         }
780
781         /*
782          * See if we can skip waking up the parent.  This is safe only if
783          * power.no_callbacks is set, because otherwise we don't know whether
784          * the resume will actually succeed.
785          */
786         if (dev->power.no_callbacks && !parent && dev->parent) {
787                 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
788                 if (dev->parent->power.disable_depth > 0
789                     || dev->parent->power.ignore_children
790                     || dev->parent->power.runtime_status == RPM_ACTIVE) {
791                         atomic_inc(&dev->parent->power.child_count);
792                         spin_unlock(&dev->parent->power.lock);
793                         retval = 1;
794                         goto no_callback;       /* Assume success. */
795                 }
796                 spin_unlock(&dev->parent->power.lock);
797         }
798
799         /* Carry out an asynchronous or a synchronous resume. */
800         if (rpmflags & RPM_ASYNC) {
801                 dev->power.request = RPM_REQ_RESUME;
802                 if (!dev->power.request_pending) {
803                         dev->power.request_pending = true;
804                         queue_work(pm_wq, &dev->power.work);
805                 }
806                 retval = 0;
807                 goto out;
808         }
809
810         if (!parent && dev->parent) {
811                 /*
812                  * Increment the parent's usage counter and resume it if
813                  * necessary.  Not needed if dev is irq-safe; then the
814                  * parent is permanently resumed.
815                  */
816                 parent = dev->parent;
817                 if (dev->power.irq_safe)
818                         goto skip_parent;
819                 spin_unlock(&dev->power.lock);
820
821                 pm_runtime_get_noresume(parent);
822
823                 spin_lock(&parent->power.lock);
824                 /*
825                  * Resume the parent if it has runtime PM enabled and not been
826                  * set to ignore its children.
827                  */
828                 if (!parent->power.disable_depth
829                     && !parent->power.ignore_children) {
830                         rpm_resume(parent, 0);
831                         if (parent->power.runtime_status != RPM_ACTIVE)
832                                 retval = -EBUSY;
833                 }
834                 spin_unlock(&parent->power.lock);
835
836                 spin_lock(&dev->power.lock);
837                 if (retval)
838                         goto out;
839                 goto repeat;
840         }
841  skip_parent:
842
843         if (dev->power.no_callbacks)
844                 goto no_callback;       /* Assume success. */
845
846         __update_runtime_status(dev, RPM_RESUMING);
847
848         callback = RPM_GET_CALLBACK(dev, runtime_resume);
849
850         dev_pm_disable_wake_irq_check(dev);
851         retval = rpm_callback(callback, dev);
852         if (retval) {
853                 __update_runtime_status(dev, RPM_SUSPENDED);
854                 pm_runtime_cancel_pending(dev);
855                 dev_pm_enable_wake_irq_check(dev, false);
856         } else {
857  no_callback:
858                 __update_runtime_status(dev, RPM_ACTIVE);
859                 pm_runtime_mark_last_busy(dev);
860                 if (parent)
861                         atomic_inc(&parent->power.child_count);
862         }
863         wake_up_all(&dev->power.wait_queue);
864
865         if (retval >= 0)
866                 rpm_idle(dev, RPM_ASYNC);
867
868  out:
869         if (parent && !dev->power.irq_safe) {
870                 spin_unlock_irq(&dev->power.lock);
871
872                 pm_runtime_put(parent);
873
874                 spin_lock_irq(&dev->power.lock);
875         }
876
877         trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
878
879         return retval;
880 }
881
882 /**
883  * pm_runtime_work - Universal runtime PM work function.
884  * @work: Work structure used for scheduling the execution of this function.
885  *
886  * Use @work to get the device object the work is to be done for, determine what
887  * is to be done and execute the appropriate runtime PM function.
888  */
889 static void pm_runtime_work(struct work_struct *work)
890 {
891         struct device *dev = container_of(work, struct device, power.work);
892         enum rpm_request req;
893
894         spin_lock_irq(&dev->power.lock);
895
896         if (!dev->power.request_pending)
897                 goto out;
898
899         req = dev->power.request;
900         dev->power.request = RPM_REQ_NONE;
901         dev->power.request_pending = false;
902
903         switch (req) {
904         case RPM_REQ_NONE:
905                 break;
906         case RPM_REQ_IDLE:
907                 rpm_idle(dev, RPM_NOWAIT);
908                 break;
909         case RPM_REQ_SUSPEND:
910                 rpm_suspend(dev, RPM_NOWAIT);
911                 break;
912         case RPM_REQ_AUTOSUSPEND:
913                 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
914                 break;
915         case RPM_REQ_RESUME:
916                 rpm_resume(dev, RPM_NOWAIT);
917                 break;
918         }
919
920  out:
921         spin_unlock_irq(&dev->power.lock);
922 }
923
924 /**
925  * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
926  * @data: Device pointer passed by pm_schedule_suspend().
927  *
928  * Check if the time is right and queue a suspend request.
929  */
930 static enum hrtimer_restart  pm_suspend_timer_fn(struct hrtimer *timer)
931 {
932         struct device *dev = container_of(timer, struct device, power.suspend_timer);
933         unsigned long flags;
934         u64 expires;
935
936         spin_lock_irqsave(&dev->power.lock, flags);
937
938         expires = dev->power.timer_expires;
939         /*
940          * If 'expires' is after the current time, we've been called
941          * too early.
942          */
943         if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
944                 dev->power.timer_expires = 0;
945                 rpm_suspend(dev, dev->power.timer_autosuspends ?
946                     (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
947         }
948
949         spin_unlock_irqrestore(&dev->power.lock, flags);
950
951         return HRTIMER_NORESTART;
952 }
953
954 /**
955  * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
956  * @dev: Device to suspend.
957  * @delay: Time to wait before submitting a suspend request, in milliseconds.
958  */
959 int pm_schedule_suspend(struct device *dev, unsigned int delay)
960 {
961         unsigned long flags;
962         u64 expires;
963         int retval;
964
965         spin_lock_irqsave(&dev->power.lock, flags);
966
967         if (!delay) {
968                 retval = rpm_suspend(dev, RPM_ASYNC);
969                 goto out;
970         }
971
972         retval = rpm_check_suspend_allowed(dev);
973         if (retval)
974                 goto out;
975
976         /* Other scheduled or pending requests need to be canceled. */
977         pm_runtime_cancel_pending(dev);
978
979         expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC;
980         dev->power.timer_expires = expires;
981         dev->power.timer_autosuspends = 0;
982         hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);
983
984  out:
985         spin_unlock_irqrestore(&dev->power.lock, flags);
986
987         return retval;
988 }
989 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
990
991 /**
992  * __pm_runtime_idle - Entry point for runtime idle operations.
993  * @dev: Device to send idle notification for.
994  * @rpmflags: Flag bits.
995  *
996  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
997  * return immediately if it is larger than zero.  Then carry out an idle
998  * notification, either synchronous or asynchronous.
999  *
1000  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1001  * or if pm_runtime_irq_safe() has been called.
1002  */
1003 int __pm_runtime_idle(struct device *dev, int rpmflags)
1004 {
1005         unsigned long flags;
1006         int retval;
1007
1008         if (rpmflags & RPM_GET_PUT) {
1009                 if (!atomic_dec_and_test(&dev->power.usage_count))
1010                         return 0;
1011         }
1012
1013         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1014
1015         spin_lock_irqsave(&dev->power.lock, flags);
1016         retval = rpm_idle(dev, rpmflags);
1017         spin_unlock_irqrestore(&dev->power.lock, flags);
1018
1019         return retval;
1020 }
1021 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
1022
1023 /**
1024  * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
1025  * @dev: Device to suspend.
1026  * @rpmflags: Flag bits.
1027  *
1028  * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1029  * return immediately if it is larger than zero.  Then carry out a suspend,
1030  * either synchronous or asynchronous.
1031  *
1032  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1033  * or if pm_runtime_irq_safe() has been called.
1034  */
1035 int __pm_runtime_suspend(struct device *dev, int rpmflags)
1036 {
1037         unsigned long flags;
1038         int retval;
1039
1040         if (rpmflags & RPM_GET_PUT) {
1041                 if (!atomic_dec_and_test(&dev->power.usage_count))
1042                         return 0;
1043         }
1044
1045         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1046
1047         spin_lock_irqsave(&dev->power.lock, flags);
1048         retval = rpm_suspend(dev, rpmflags);
1049         spin_unlock_irqrestore(&dev->power.lock, flags);
1050
1051         return retval;
1052 }
1053 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
1054
1055 /**
1056  * __pm_runtime_resume - Entry point for runtime resume operations.
1057  * @dev: Device to resume.
1058  * @rpmflags: Flag bits.
1059  *
1060  * If the RPM_GET_PUT flag is set, increment the device's usage count.  Then
1061  * carry out a resume, either synchronous or asynchronous.
1062  *
1063  * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1064  * or if pm_runtime_irq_safe() has been called.
1065  */
1066 int __pm_runtime_resume(struct device *dev, int rpmflags)
1067 {
1068         unsigned long flags;
1069         int retval;
1070
1071         might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
1072                         dev->power.runtime_status != RPM_ACTIVE);
1073
1074         if (rpmflags & RPM_GET_PUT)
1075                 atomic_inc(&dev->power.usage_count);
1076
1077         spin_lock_irqsave(&dev->power.lock, flags);
1078         retval = rpm_resume(dev, rpmflags);
1079         spin_unlock_irqrestore(&dev->power.lock, flags);
1080
1081         return retval;
1082 }
1083 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
1084
1085 /**
1086  * pm_runtime_get_if_in_use - Conditionally bump up the device's usage counter.
1087  * @dev: Device to handle.
1088  *
1089  * Return -EINVAL if runtime PM is disabled for the device.
1090  *
1091  * If that's not the case and if the device's runtime PM status is RPM_ACTIVE
1092  * and the runtime PM usage counter is nonzero, increment the counter and
1093  * return 1.  Otherwise return 0 without changing the counter.
1094  */
1095 int pm_runtime_get_if_in_use(struct device *dev)
1096 {
1097         unsigned long flags;
1098         int retval;
1099
1100         spin_lock_irqsave(&dev->power.lock, flags);
1101         retval = dev->power.disable_depth > 0 ? -EINVAL :
1102                 dev->power.runtime_status == RPM_ACTIVE
1103                         && atomic_inc_not_zero(&dev->power.usage_count);
1104         spin_unlock_irqrestore(&dev->power.lock, flags);
1105         return retval;
1106 }
1107 EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
1108
1109 /**
1110  * __pm_runtime_set_status - Set runtime PM status of a device.
1111  * @dev: Device to handle.
1112  * @status: New runtime PM status of the device.
1113  *
1114  * If runtime PM of the device is disabled or its power.runtime_error field is
1115  * different from zero, the status may be changed either to RPM_ACTIVE, or to
1116  * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1117  * However, if the device has a parent and the parent is not active, and the
1118  * parent's power.ignore_children flag is unset, the device's status cannot be
1119  * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1120  *
1121  * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1122  * and the device parent's counter of unsuspended children is modified to
1123  * reflect the new status.  If the new status is RPM_SUSPENDED, an idle
1124  * notification request for the parent is submitted.
1125  *
1126  * If @dev has any suppliers (as reflected by device links to them), and @status
1127  * is RPM_ACTIVE, they will be activated upfront and if the activation of one
1128  * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead
1129  * of the @status value) and the suppliers will be deacticated on exit.  The
1130  * error returned by the failing supplier activation will be returned in that
1131  * case.
1132  */
1133 int __pm_runtime_set_status(struct device *dev, unsigned int status)
1134 {
1135         struct device *parent = dev->parent;
1136         bool notify_parent = false;
1137         int error = 0;
1138
1139         if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1140                 return -EINVAL;
1141
1142         spin_lock_irq(&dev->power.lock);
1143
1144         /*
1145          * Prevent PM-runtime from being enabled for the device or return an
1146          * error if it is enabled already and working.
1147          */
1148         if (dev->power.runtime_error || dev->power.disable_depth)
1149                 dev->power.disable_depth++;
1150         else
1151                 error = -EAGAIN;
1152
1153         spin_unlock_irq(&dev->power.lock);
1154
1155         if (error)
1156                 return error;
1157
1158         /*
1159          * If the new status is RPM_ACTIVE, the suppliers can be activated
1160          * upfront regardless of the current status, because next time
1161          * rpm_put_suppliers() runs, the rpm_active refcounts of the links
1162          * involved will be dropped down to one anyway.
1163          */
1164         if (status == RPM_ACTIVE) {
1165                 int idx = device_links_read_lock();
1166
1167                 error = rpm_get_suppliers(dev);
1168                 if (error)
1169                         status = RPM_SUSPENDED;
1170
1171                 device_links_read_unlock(idx);
1172         }
1173
1174         spin_lock_irq(&dev->power.lock);
1175
1176         if (dev->power.runtime_status == status || !parent)
1177                 goto out_set;
1178
1179         if (status == RPM_SUSPENDED) {
1180                 atomic_add_unless(&parent->power.child_count, -1, 0);
1181                 notify_parent = !parent->power.ignore_children;
1182         } else {
1183                 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1184
1185                 /*
1186                  * It is invalid to put an active child under a parent that is
1187                  * not active, has runtime PM enabled and the
1188                  * 'power.ignore_children' flag unset.
1189                  */
1190                 if (!parent->power.disable_depth
1191                     && !parent->power.ignore_children
1192                     && parent->power.runtime_status != RPM_ACTIVE) {
1193                         dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1194                                 dev_name(dev),
1195                                 dev_name(parent));
1196                         error = -EBUSY;
1197                 } else if (dev->power.runtime_status == RPM_SUSPENDED) {
1198                         atomic_inc(&parent->power.child_count);
1199                 }
1200
1201                 spin_unlock(&parent->power.lock);
1202
1203                 if (error) {
1204                         status = RPM_SUSPENDED;
1205                         goto out;
1206                 }
1207         }
1208
1209  out_set:
1210         __update_runtime_status(dev, status);
1211         if (!error)
1212                 dev->power.runtime_error = 0;
1213
1214  out:
1215         spin_unlock_irq(&dev->power.lock);
1216
1217         if (notify_parent)
1218                 pm_request_idle(parent);
1219
1220         if (status == RPM_SUSPENDED) {
1221                 int idx = device_links_read_lock();
1222
1223                 rpm_put_suppliers(dev);
1224
1225                 device_links_read_unlock(idx);
1226         }
1227
1228         pm_runtime_enable(dev);
1229
1230         return error;
1231 }
1232 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1233
1234 /**
1235  * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1236  * @dev: Device to handle.
1237  *
1238  * Flush all pending requests for the device from pm_wq and wait for all
1239  * runtime PM operations involving the device in progress to complete.
1240  *
1241  * Should be called under dev->power.lock with interrupts disabled.
1242  */
1243 static void __pm_runtime_barrier(struct device *dev)
1244 {
1245         pm_runtime_deactivate_timer(dev);
1246
1247         if (dev->power.request_pending) {
1248                 dev->power.request = RPM_REQ_NONE;
1249                 spin_unlock_irq(&dev->power.lock);
1250
1251                 cancel_work_sync(&dev->power.work);
1252
1253                 spin_lock_irq(&dev->power.lock);
1254                 dev->power.request_pending = false;
1255         }
1256
1257         if (dev->power.runtime_status == RPM_SUSPENDING
1258             || dev->power.runtime_status == RPM_RESUMING
1259             || dev->power.idle_notification) {
1260                 DEFINE_WAIT(wait);
1261
1262                 /* Suspend, wake-up or idle notification in progress. */
1263                 for (;;) {
1264                         prepare_to_wait(&dev->power.wait_queue, &wait,
1265                                         TASK_UNINTERRUPTIBLE);
1266                         if (dev->power.runtime_status != RPM_SUSPENDING
1267                             && dev->power.runtime_status != RPM_RESUMING
1268                             && !dev->power.idle_notification)
1269                                 break;
1270                         spin_unlock_irq(&dev->power.lock);
1271
1272                         schedule();
1273
1274                         spin_lock_irq(&dev->power.lock);
1275                 }
1276                 finish_wait(&dev->power.wait_queue, &wait);
1277         }
1278 }
1279
1280 /**
1281  * pm_runtime_barrier - Flush pending requests and wait for completions.
1282  * @dev: Device to handle.
1283  *
1284  * Prevent the device from being suspended by incrementing its usage counter and
1285  * if there's a pending resume request for the device, wake the device up.
1286  * Next, make sure that all pending requests for the device have been flushed
1287  * from pm_wq and wait for all runtime PM operations involving the device in
1288  * progress to complete.
1289  *
1290  * Return value:
1291  * 1, if there was a resume request pending and the device had to be woken up,
1292  * 0, otherwise
1293  */
1294 int pm_runtime_barrier(struct device *dev)
1295 {
1296         int retval = 0;
1297
1298         pm_runtime_get_noresume(dev);
1299         spin_lock_irq(&dev->power.lock);
1300
1301         if (dev->power.request_pending
1302             && dev->power.request == RPM_REQ_RESUME) {
1303                 rpm_resume(dev, 0);
1304                 retval = 1;
1305         }
1306
1307         __pm_runtime_barrier(dev);
1308
1309         spin_unlock_irq(&dev->power.lock);
1310         pm_runtime_put_noidle(dev);
1311
1312         return retval;
1313 }
1314 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1315
1316 /**
1317  * __pm_runtime_disable - Disable runtime PM of a device.
1318  * @dev: Device to handle.
1319  * @check_resume: If set, check if there's a resume request for the device.
1320  *
1321  * Increment power.disable_depth for the device and if it was zero previously,
1322  * cancel all pending runtime PM requests for the device and wait for all
1323  * operations in progress to complete.  The device can be either active or
1324  * suspended after its runtime PM has been disabled.
1325  *
1326  * If @check_resume is set and there's a resume request pending when
1327  * __pm_runtime_disable() is called and power.disable_depth is zero, the
1328  * function will wake up the device before disabling its runtime PM.
1329  */
1330 void __pm_runtime_disable(struct device *dev, bool check_resume)
1331 {
1332         spin_lock_irq(&dev->power.lock);
1333
1334         if (dev->power.disable_depth > 0) {
1335                 dev->power.disable_depth++;
1336                 goto out;
1337         }
1338
1339         /*
1340          * Wake up the device if there's a resume request pending, because that
1341          * means there probably is some I/O to process and disabling runtime PM
1342          * shouldn't prevent the device from processing the I/O.
1343          */
1344         if (check_resume && dev->power.request_pending
1345             && dev->power.request == RPM_REQ_RESUME) {
1346                 /*
1347                  * Prevent suspends and idle notifications from being carried
1348                  * out after we have woken up the device.
1349                  */
1350                 pm_runtime_get_noresume(dev);
1351
1352                 rpm_resume(dev, 0);
1353
1354                 pm_runtime_put_noidle(dev);
1355         }
1356
1357         /* Update time accounting before disabling PM-runtime. */
1358         update_pm_runtime_accounting(dev);
1359
1360         if (!dev->power.disable_depth++)
1361                 __pm_runtime_barrier(dev);
1362
1363  out:
1364         spin_unlock_irq(&dev->power.lock);
1365 }
1366 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1367
1368 /**
1369  * pm_runtime_enable - Enable runtime PM of a device.
1370  * @dev: Device to handle.
1371  */
1372 void pm_runtime_enable(struct device *dev)
1373 {
1374         unsigned long flags;
1375
1376         spin_lock_irqsave(&dev->power.lock, flags);
1377
1378         if (dev->power.disable_depth > 0) {
1379                 dev->power.disable_depth--;
1380
1381                 /* About to enable runtime pm, set accounting_timestamp to now */
1382                 if (!dev->power.disable_depth)
1383                         dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
1384         } else {
1385                 dev_warn(dev, "Unbalanced %s!\n", __func__);
1386         }
1387
1388         WARN(!dev->power.disable_depth &&
1389              dev->power.runtime_status == RPM_SUSPENDED &&
1390              !dev->power.ignore_children &&
1391              atomic_read(&dev->power.child_count) > 0,
1392              "Enabling runtime PM for inactive device (%s) with active children\n",
1393              dev_name(dev));
1394
1395         spin_unlock_irqrestore(&dev->power.lock, flags);
1396 }
1397 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1398
1399 /**
1400  * pm_runtime_forbid - Block runtime PM of a device.
1401  * @dev: Device to handle.
1402  *
1403  * Increase the device's usage count and clear its power.runtime_auto flag,
1404  * so that it cannot be suspended at run time until pm_runtime_allow() is called
1405  * for it.
1406  */
1407 void pm_runtime_forbid(struct device *dev)
1408 {
1409         spin_lock_irq(&dev->power.lock);
1410         if (!dev->power.runtime_auto)
1411                 goto out;
1412
1413         dev->power.runtime_auto = false;
1414         atomic_inc(&dev->power.usage_count);
1415         rpm_resume(dev, 0);
1416
1417  out:
1418         spin_unlock_irq(&dev->power.lock);
1419 }
1420 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1421
1422 /**
1423  * pm_runtime_allow - Unblock runtime PM of a device.
1424  * @dev: Device to handle.
1425  *
1426  * Decrease the device's usage count and set its power.runtime_auto flag.
1427  */
1428 void pm_runtime_allow(struct device *dev)
1429 {
1430         spin_lock_irq(&dev->power.lock);
1431         if (dev->power.runtime_auto)
1432                 goto out;
1433
1434         dev->power.runtime_auto = true;
1435         if (atomic_dec_and_test(&dev->power.usage_count))
1436                 rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1437
1438  out:
1439         spin_unlock_irq(&dev->power.lock);
1440 }
1441 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1442
1443 /**
1444  * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1445  * @dev: Device to handle.
1446  *
1447  * Set the power.no_callbacks flag, which tells the PM core that this
1448  * device is power-managed through its parent and has no runtime PM
1449  * callbacks of its own.  The runtime sysfs attributes will be removed.
1450  */
1451 void pm_runtime_no_callbacks(struct device *dev)
1452 {
1453         spin_lock_irq(&dev->power.lock);
1454         dev->power.no_callbacks = 1;
1455         spin_unlock_irq(&dev->power.lock);
1456         if (device_is_registered(dev))
1457                 rpm_sysfs_remove(dev);
1458 }
1459 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1460
1461 /**
1462  * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1463  * @dev: Device to handle
1464  *
1465  * Set the power.irq_safe flag, which tells the PM core that the
1466  * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1467  * always be invoked with the spinlock held and interrupts disabled.  It also
1468  * causes the parent's usage counter to be permanently incremented, preventing
1469  * the parent from runtime suspending -- otherwise an irq-safe child might have
1470  * to wait for a non-irq-safe parent.
1471  */
1472 void pm_runtime_irq_safe(struct device *dev)
1473 {
1474         if (dev->parent)
1475                 pm_runtime_get_sync(dev->parent);
1476         spin_lock_irq(&dev->power.lock);
1477         dev->power.irq_safe = 1;
1478         spin_unlock_irq(&dev->power.lock);
1479 }
1480 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1481
1482 /**
1483  * update_autosuspend - Handle a change to a device's autosuspend settings.
1484  * @dev: Device to handle.
1485  * @old_delay: The former autosuspend_delay value.
1486  * @old_use: The former use_autosuspend value.
1487  *
1488  * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1489  * set; otherwise allow it.  Send an idle notification if suspends are allowed.
1490  *
1491  * This function must be called under dev->power.lock with interrupts disabled.
1492  */
1493 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1494 {
1495         int delay = dev->power.autosuspend_delay;
1496
1497         /* Should runtime suspend be prevented now? */
1498         if (dev->power.use_autosuspend && delay < 0) {
1499
1500                 /* If it used to be allowed then prevent it. */
1501                 if (!old_use || old_delay >= 0) {
1502                         atomic_inc(&dev->power.usage_count);
1503                         rpm_resume(dev, 0);
1504                 }
1505         }
1506
1507         /* Runtime suspend should be allowed now. */
1508         else {
1509
1510                 /* If it used to be prevented then allow it. */
1511                 if (old_use && old_delay < 0)
1512                         atomic_dec(&dev->power.usage_count);
1513
1514                 /* Maybe we can autosuspend now. */
1515                 rpm_idle(dev, RPM_AUTO);
1516         }
1517 }
1518
1519 /**
1520  * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1521  * @dev: Device to handle.
1522  * @delay: Value of the new delay in milliseconds.
1523  *
1524  * Set the device's power.autosuspend_delay value.  If it changes to negative
1525  * and the power.use_autosuspend flag is set, prevent runtime suspends.  If it
1526  * changes the other way, allow runtime suspends.
1527  */
1528 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1529 {
1530         int old_delay, old_use;
1531
1532         spin_lock_irq(&dev->power.lock);
1533         old_delay = dev->power.autosuspend_delay;
1534         old_use = dev->power.use_autosuspend;
1535         dev->power.autosuspend_delay = delay;
1536         update_autosuspend(dev, old_delay, old_use);
1537         spin_unlock_irq(&dev->power.lock);
1538 }
1539 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1540
1541 /**
1542  * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1543  * @dev: Device to handle.
1544  * @use: New value for use_autosuspend.
1545  *
1546  * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1547  * suspends as needed.
1548  */
1549 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1550 {
1551         int old_delay, old_use;
1552
1553         spin_lock_irq(&dev->power.lock);
1554         old_delay = dev->power.autosuspend_delay;
1555         old_use = dev->power.use_autosuspend;
1556         dev->power.use_autosuspend = use;
1557         update_autosuspend(dev, old_delay, old_use);
1558         spin_unlock_irq(&dev->power.lock);
1559 }
1560 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1561
1562 /**
1563  * pm_runtime_init - Initialize runtime PM fields in given device object.
1564  * @dev: Device object to initialize.
1565  */
1566 void pm_runtime_init(struct device *dev)
1567 {
1568         dev->power.runtime_status = RPM_SUSPENDED;
1569         dev->power.idle_notification = false;
1570
1571         dev->power.disable_depth = 1;
1572         atomic_set(&dev->power.usage_count, 0);
1573
1574         dev->power.runtime_error = 0;
1575
1576         atomic_set(&dev->power.child_count, 0);
1577         pm_suspend_ignore_children(dev, false);
1578         dev->power.runtime_auto = true;
1579
1580         dev->power.request_pending = false;
1581         dev->power.request = RPM_REQ_NONE;
1582         dev->power.deferred_resume = false;
1583         INIT_WORK(&dev->power.work, pm_runtime_work);
1584
1585         dev->power.timer_expires = 0;
1586         hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1587         dev->power.suspend_timer.function = pm_suspend_timer_fn;
1588
1589         init_waitqueue_head(&dev->power.wait_queue);
1590 }
1591
1592 /**
1593  * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1594  * @dev: Device object to re-initialize.
1595  */
1596 void pm_runtime_reinit(struct device *dev)
1597 {
1598         if (!pm_runtime_enabled(dev)) {
1599                 if (dev->power.runtime_status == RPM_ACTIVE)
1600                         pm_runtime_set_suspended(dev);
1601                 if (dev->power.irq_safe) {
1602                         spin_lock_irq(&dev->power.lock);
1603                         dev->power.irq_safe = 0;
1604                         spin_unlock_irq(&dev->power.lock);
1605                         if (dev->parent)
1606                                 pm_runtime_put(dev->parent);
1607                 }
1608         }
1609 }
1610
1611 /**
1612  * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1613  * @dev: Device object being removed from device hierarchy.
1614  */
1615 void pm_runtime_remove(struct device *dev)
1616 {
1617         __pm_runtime_disable(dev, false);
1618         pm_runtime_reinit(dev);
1619 }
1620
1621 /**
1622  * pm_runtime_clean_up_links - Prepare links to consumers for driver removal.
1623  * @dev: Device whose driver is going to be removed.
1624  *
1625  * Check links from this device to any consumers and if any of them have active
1626  * runtime PM references to the device, drop the usage counter of the device
1627  * (as many times as needed).
1628  *
1629  * Links with the DL_FLAG_STATELESS flag set are ignored.
1630  *
1631  * Since the device is guaranteed to be runtime-active at the point this is
1632  * called, nothing else needs to be done here.
1633  *
1634  * Moreover, this is called after device_links_busy() has returned 'false', so
1635  * the status of each link is guaranteed to be DL_STATE_SUPPLIER_UNBIND and
1636  * therefore rpm_active can't be manipulated concurrently.
1637  */
1638 void pm_runtime_clean_up_links(struct device *dev)
1639 {
1640         struct device_link *link;
1641         int idx;
1642
1643         idx = device_links_read_lock();
1644
1645         list_for_each_entry_rcu(link, &dev->links.consumers, s_node) {
1646                 if (link->flags & DL_FLAG_STATELESS)
1647                         continue;
1648
1649                 while (refcount_dec_not_one(&link->rpm_active))
1650                         pm_runtime_put_noidle(dev);
1651         }
1652
1653         device_links_read_unlock(idx);
1654 }
1655
1656 /**
1657  * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
1658  * @dev: Consumer device.
1659  */
1660 void pm_runtime_get_suppliers(struct device *dev)
1661 {
1662         struct device_link *link;
1663         int idx;
1664
1665         idx = device_links_read_lock();
1666
1667         list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
1668                 if (link->flags & DL_FLAG_PM_RUNTIME) {
1669                         link->supplier_preactivated = true;
1670                         refcount_inc(&link->rpm_active);
1671                         pm_runtime_get_sync(link->supplier);
1672                 }
1673
1674         device_links_read_unlock(idx);
1675 }
1676
1677 /**
1678  * pm_runtime_put_suppliers - Drop references to supplier devices.
1679  * @dev: Consumer device.
1680  */
1681 void pm_runtime_put_suppliers(struct device *dev)
1682 {
1683         struct device_link *link;
1684         int idx;
1685
1686         idx = device_links_read_lock();
1687
1688         list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
1689                 if (link->supplier_preactivated) {
1690                         link->supplier_preactivated = false;
1691                         if (refcount_dec_not_one(&link->rpm_active))
1692                                 pm_runtime_put(link->supplier);
1693                 }
1694
1695         device_links_read_unlock(idx);
1696 }
1697
1698 void pm_runtime_new_link(struct device *dev)
1699 {
1700         spin_lock_irq(&dev->power.lock);
1701         dev->power.links_count++;
1702         spin_unlock_irq(&dev->power.lock);
1703 }
1704
1705 void pm_runtime_drop_link(struct device *dev)
1706 {
1707         spin_lock_irq(&dev->power.lock);
1708         WARN_ON(dev->power.links_count == 0);
1709         dev->power.links_count--;
1710         spin_unlock_irq(&dev->power.lock);
1711 }
1712
1713 static bool pm_runtime_need_not_resume(struct device *dev)
1714 {
1715         return atomic_read(&dev->power.usage_count) <= 1 &&
1716                 (atomic_read(&dev->power.child_count) == 0 ||
1717                  dev->power.ignore_children);
1718 }
1719
1720 /**
1721  * pm_runtime_force_suspend - Force a device into suspend state if needed.
1722  * @dev: Device to suspend.
1723  *
1724  * Disable runtime PM so we safely can check the device's runtime PM status and
1725  * if it is active, invoke its ->runtime_suspend callback to suspend it and
1726  * change its runtime PM status field to RPM_SUSPENDED.  Also, if the device's
1727  * usage and children counters don't indicate that the device was in use before
1728  * the system-wide transition under way, decrement its parent's children counter
1729  * (if there is a parent).  Keep runtime PM disabled to preserve the state
1730  * unless we encounter errors.
1731  *
1732  * Typically this function may be invoked from a system suspend callback to make
1733  * sure the device is put into low power state and it should only be used during
1734  * system-wide PM transitions to sleep states.  It assumes that the analogous
1735  * pm_runtime_force_resume() will be used to resume the device.
1736  */
1737 int pm_runtime_force_suspend(struct device *dev)
1738 {
1739         int (*callback)(struct device *);
1740         int ret;
1741
1742         pm_runtime_disable(dev);
1743         if (pm_runtime_status_suspended(dev))
1744                 return 0;
1745
1746         callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1747
1748         ret = callback ? callback(dev) : 0;
1749         if (ret)
1750                 goto err;
1751
1752         /*
1753          * If the device can stay in suspend after the system-wide transition
1754          * to the working state that will follow, drop the children counter of
1755          * its parent, but set its status to RPM_SUSPENDED anyway in case this
1756          * function will be called again for it in the meantime.
1757          */
1758         if (pm_runtime_need_not_resume(dev))
1759                 pm_runtime_set_suspended(dev);
1760         else
1761                 __update_runtime_status(dev, RPM_SUSPENDED);
1762
1763         return 0;
1764
1765 err:
1766         pm_runtime_enable(dev);
1767         return ret;
1768 }
1769 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1770
1771 /**
1772  * pm_runtime_force_resume - Force a device into resume state if needed.
1773  * @dev: Device to resume.
1774  *
1775  * Prior invoking this function we expect the user to have brought the device
1776  * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1777  * those actions and bring the device into full power, if it is expected to be
1778  * used on system resume.  In the other case, we defer the resume to be managed
1779  * via runtime PM.
1780  *
1781  * Typically this function may be invoked from a system resume callback.
1782  */
1783 int pm_runtime_force_resume(struct device *dev)
1784 {
1785         int (*callback)(struct device *);
1786         int ret = 0;
1787
1788         if (!pm_runtime_status_suspended(dev) || pm_runtime_need_not_resume(dev))
1789                 goto out;
1790
1791         /*
1792          * The value of the parent's children counter is correct already, so
1793          * just update the status of the device.
1794          */
1795         __update_runtime_status(dev, RPM_ACTIVE);
1796
1797         callback = RPM_GET_CALLBACK(dev, runtime_resume);
1798
1799         ret = callback ? callback(dev) : 0;
1800         if (ret) {
1801                 pm_runtime_set_suspended(dev);
1802                 goto out;
1803         }
1804
1805         pm_runtime_mark_last_busy(dev);
1806 out:
1807         pm_runtime_enable(dev);
1808         return ret;
1809 }
1810 EXPORT_SYMBOL_GPL(pm_runtime_force_resume);