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1/*
2 * drivers/base/power/runtime.c - Helper functions for device runtime PM
3 *
4 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
6 *
7 * This file is released under the GPLv2.
8 */
9
10#include <linux/sched.h>
11#include <linux/export.h>
12#include <linux/pm_runtime.h>
13#include <trace/events/rpm.h>
14#include "power.h"
15
16#define RPM_GET_CALLBACK(dev, cb) \
17({ \
18 int (*__rpm_cb)(struct device *__d); \
19 \
20 if (dev->pm_domain) \
21 __rpm_cb = dev->pm_domain->ops.cb; \
22 else if (dev->type && dev->type->pm) \
23 __rpm_cb = dev->type->pm->cb; \
24 else if (dev->class && dev->class->pm) \
25 __rpm_cb = dev->class->pm->cb; \
26 else if (dev->bus && dev->bus->pm) \
27 __rpm_cb = dev->bus->pm->cb; \
28 else \
29 __rpm_cb = NULL; \
30 \
31 if (!__rpm_cb && dev->driver && dev->driver->pm) \
32 __rpm_cb = dev->driver->pm->cb; \
33 \
34 __rpm_cb; \
35})
36
37static int (*rpm_get_suspend_cb(struct device *dev))(struct device *)
38{
39 return RPM_GET_CALLBACK(dev, runtime_suspend);
40}
41
42static int (*rpm_get_resume_cb(struct device *dev))(struct device *)
43{
44 return RPM_GET_CALLBACK(dev, runtime_resume);
45}
46
47#ifdef CONFIG_PM_RUNTIME
48static int (*rpm_get_idle_cb(struct device *dev))(struct device *)
49{
50 return RPM_GET_CALLBACK(dev, runtime_idle);
51}
52
53static int rpm_resume(struct device *dev, int rpmflags);
54static 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 */
67void update_pm_runtime_accounting(struct device *dev)
68{
69 unsigned long now = jiffies;
70 unsigned long delta;
71
72 delta = now - dev->power.accounting_timestamp;
73
74 dev->power.accounting_timestamp = now;
75
76 if (dev->power.disable_depth > 0)
77 return;
78
79 if (dev->power.runtime_status == RPM_SUSPENDED)
80 dev->power.suspended_jiffies += delta;
81 else
82 dev->power.active_jiffies += delta;
83}
84
85static void __update_runtime_status(struct device *dev, enum rpm_status status)
86{
87 update_pm_runtime_accounting(dev);
88 dev->power.runtime_status = status;
89}
90
91/**
92 * pm_runtime_deactivate_timer - Deactivate given device's suspend timer.
93 * @dev: Device to handle.
94 */
95static void pm_runtime_deactivate_timer(struct device *dev)
96{
97 if (dev->power.timer_expires > 0) {
98 del_timer(&dev->power.suspend_timer);
99 dev->power.timer_expires = 0;
100 }
101}
102
103/**
104 * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests.
105 * @dev: Device to handle.
106 */
107static void pm_runtime_cancel_pending(struct device *dev)
108{
109 pm_runtime_deactivate_timer(dev);
110 /*
111 * In case there's a request pending, make sure its work function will
112 * return without doing anything.
113 */
114 dev->power.request = RPM_REQ_NONE;
115}
116
117/*
118 * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time.
119 * @dev: Device to handle.
120 *
121 * Compute the autosuspend-delay expiration time based on the device's
122 * power.last_busy time. If the delay has already expired or is disabled
123 * (negative) or the power.use_autosuspend flag isn't set, return 0.
124 * Otherwise return the expiration time in jiffies (adjusted to be nonzero).
125 *
126 * This function may be called either with or without dev->power.lock held.
127 * Either way it can be racy, since power.last_busy may be updated at any time.
128 */
129unsigned long pm_runtime_autosuspend_expiration(struct device *dev)
130{
131 int autosuspend_delay;
132 long elapsed;
133 unsigned long last_busy;
134 unsigned long expires = 0;
135
136 if (!dev->power.use_autosuspend)
137 goto out;
138
139 autosuspend_delay = ACCESS_ONCE(dev->power.autosuspend_delay);
140 if (autosuspend_delay < 0)
141 goto out;
142
143 last_busy = ACCESS_ONCE(dev->power.last_busy);
144 elapsed = jiffies - last_busy;
145 if (elapsed < 0)
146 goto out; /* jiffies has wrapped around. */
147
148 /*
149 * If the autosuspend_delay is >= 1 second, align the timer by rounding
150 * up to the nearest second.
151 */
152 expires = last_busy + msecs_to_jiffies(autosuspend_delay);
153 if (autosuspend_delay >= 1000)
154 expires = round_jiffies(expires);
155 expires += !expires;
156 if (elapsed >= expires - last_busy)
157 expires = 0; /* Already expired. */
158
159 out:
160 return expires;
161}
162EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
163
164static int dev_memalloc_noio(struct device *dev, void *data)
165{
166 return dev->power.memalloc_noio;
167}
168
169/*
170 * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag.
171 * @dev: Device to handle.
172 * @enable: True for setting the flag and False for clearing the flag.
173 *
174 * Set the flag for all devices in the path from the device to the
175 * root device in the device tree if @enable is true, otherwise clear
176 * the flag for devices in the path whose siblings don't set the flag.
177 *
178 * The function should only be called by block device, or network
179 * device driver for solving the deadlock problem during runtime
180 * resume/suspend:
181 *
182 * If memory allocation with GFP_KERNEL is called inside runtime
183 * resume/suspend callback of any one of its ancestors(or the
184 * block device itself), the deadlock may be triggered inside the
185 * memory allocation since it might not complete until the block
186 * device becomes active and the involed page I/O finishes. The
187 * situation is pointed out first by Alan Stern. Network device
188 * are involved in iSCSI kind of situation.
189 *
190 * The lock of dev_hotplug_mutex is held in the function for handling
191 * hotplug race because pm_runtime_set_memalloc_noio() may be called
192 * in async probe().
193 *
194 * The function should be called between device_add() and device_del()
195 * on the affected device(block/network device).
196 */
197void pm_runtime_set_memalloc_noio(struct device *dev, bool enable)
198{
199 static DEFINE_MUTEX(dev_hotplug_mutex);
200
201 mutex_lock(&dev_hotplug_mutex);
202 for (;;) {
203 bool enabled;
204
205 /* hold power lock since bitfield is not SMP-safe. */
206 spin_lock_irq(&dev->power.lock);
207 enabled = dev->power.memalloc_noio;
208 dev->power.memalloc_noio = enable;
209 spin_unlock_irq(&dev->power.lock);
210
211 /*
212 * not need to enable ancestors any more if the device
213 * has been enabled.
214 */
215 if (enabled && enable)
216 break;
217
218 dev = dev->parent;
219
220 /*
221 * clear flag of the parent device only if all the
222 * children don't set the flag because ancestor's
223 * flag was set by any one of the descendants.
224 */
225 if (!dev || (!enable &&
226 device_for_each_child(dev, NULL,
227 dev_memalloc_noio)))
228 break;
229 }
230 mutex_unlock(&dev_hotplug_mutex);
231}
232EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
233
234/**
235 * rpm_check_suspend_allowed - Test whether a device may be suspended.
236 * @dev: Device to test.
237 */
238static int rpm_check_suspend_allowed(struct device *dev)
239{
240 int retval = 0;
241
242 if (dev->power.runtime_error)
243 retval = -EINVAL;
244 else if (dev->power.disable_depth > 0)
245 retval = -EACCES;
246 else if (atomic_read(&dev->power.usage_count) > 0)
247 retval = -EAGAIN;
248 else if (!pm_children_suspended(dev))
249 retval = -EBUSY;
250
251 /* Pending resume requests take precedence over suspends. */
252 else if ((dev->power.deferred_resume
253 && dev->power.runtime_status == RPM_SUSPENDING)
254 || (dev->power.request_pending
255 && dev->power.request == RPM_REQ_RESUME))
256 retval = -EAGAIN;
257 else if (__dev_pm_qos_read_value(dev) < 0)
258 retval = -EPERM;
259 else if (dev->power.runtime_status == RPM_SUSPENDED)
260 retval = 1;
261
262 return retval;
263}
264
265/**
266 * __rpm_callback - Run a given runtime PM callback for a given device.
267 * @cb: Runtime PM callback to run.
268 * @dev: Device to run the callback for.
269 */
270static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
271 __releases(&dev->power.lock) __acquires(&dev->power.lock)
272{
273 int retval;
274
275 if (dev->power.irq_safe)
276 spin_unlock(&dev->power.lock);
277 else
278 spin_unlock_irq(&dev->power.lock);
279
280 retval = cb(dev);
281
282 if (dev->power.irq_safe)
283 spin_lock(&dev->power.lock);
284 else
285 spin_lock_irq(&dev->power.lock);
286
287 return retval;
288}
289
290/**
291 * rpm_idle - Notify device bus type if the device can be suspended.
292 * @dev: Device to notify the bus type about.
293 * @rpmflags: Flag bits.
294 *
295 * Check if the device's runtime PM status allows it to be suspended. If
296 * another idle notification has been started earlier, return immediately. If
297 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
298 * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
299 * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
300 *
301 * This function must be called under dev->power.lock with interrupts disabled.
302 */
303static int rpm_idle(struct device *dev, int rpmflags)
304{
305 int (*callback)(struct device *);
306 int retval;
307
308 trace_rpm_idle(dev, rpmflags);
309 retval = rpm_check_suspend_allowed(dev);
310 if (retval < 0)
311 ; /* Conditions are wrong. */
312
313 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
314 else if (dev->power.runtime_status != RPM_ACTIVE)
315 retval = -EAGAIN;
316
317 /*
318 * Any pending request other than an idle notification takes
319 * precedence over us, except that the timer may be running.
320 */
321 else if (dev->power.request_pending &&
322 dev->power.request > RPM_REQ_IDLE)
323 retval = -EAGAIN;
324
325 /* Act as though RPM_NOWAIT is always set. */
326 else if (dev->power.idle_notification)
327 retval = -EINPROGRESS;
328 if (retval)
329 goto out;
330
331 /* Pending requests need to be canceled. */
332 dev->power.request = RPM_REQ_NONE;
333
334 if (dev->power.no_callbacks)
335 goto out;
336
337 /* Carry out an asynchronous or a synchronous idle notification. */
338 if (rpmflags & RPM_ASYNC) {
339 dev->power.request = RPM_REQ_IDLE;
340 if (!dev->power.request_pending) {
341 dev->power.request_pending = true;
342 queue_work(pm_wq, &dev->power.work);
343 }
344 trace_rpm_return_int(dev, _THIS_IP_, 0);
345 return 0;
346 }
347
348 dev->power.idle_notification = true;
349
350 callback = rpm_get_idle_cb(dev);
351
352 if (callback)
353 retval = __rpm_callback(callback, dev);
354
355 dev->power.idle_notification = false;
356 wake_up_all(&dev->power.wait_queue);
357
358 out:
359 trace_rpm_return_int(dev, _THIS_IP_, retval);
360 return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
361}
362
363/**
364 * rpm_callback - Run a given runtime PM callback for a given device.
365 * @cb: Runtime PM callback to run.
366 * @dev: Device to run the callback for.
367 */
368static int rpm_callback(int (*cb)(struct device *), struct device *dev)
369{
370 int retval;
371
372 if (!cb)
373 return -ENOSYS;
374
375 if (dev->power.memalloc_noio) {
376 unsigned int noio_flag;
377
378 /*
379 * Deadlock might be caused if memory allocation with
380 * GFP_KERNEL happens inside runtime_suspend and
381 * runtime_resume callbacks of one block device's
382 * ancestor or the block device itself. Network
383 * device might be thought as part of iSCSI block
384 * device, so network device and its ancestor should
385 * be marked as memalloc_noio too.
386 */
387 noio_flag = memalloc_noio_save();
388 retval = __rpm_callback(cb, dev);
389 memalloc_noio_restore(noio_flag);
390 } else {
391 retval = __rpm_callback(cb, dev);
392 }
393
394 dev->power.runtime_error = retval;
395 return retval != -EACCES ? retval : -EIO;
396}
397
398/**
399 * rpm_suspend - Carry out runtime suspend of given device.
400 * @dev: Device to suspend.
401 * @rpmflags: Flag bits.
402 *
403 * Check if the device's runtime PM status allows it to be suspended.
404 * Cancel a pending idle notification, autosuspend or suspend. If
405 * another suspend has been started earlier, either return immediately
406 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
407 * flags. If the RPM_ASYNC flag is set then queue a suspend request;
408 * otherwise run the ->runtime_suspend() callback directly. When
409 * ->runtime_suspend succeeded, if a deferred resume was requested while
410 * the callback was running then carry it out, otherwise send an idle
411 * notification for its parent (if the suspend succeeded and both
412 * ignore_children of parent->power and irq_safe of dev->power are not set).
413 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
414 * flag is set and the next autosuspend-delay expiration time is in the
415 * future, schedule another autosuspend attempt.
416 *
417 * This function must be called under dev->power.lock with interrupts disabled.
418 */
419static int rpm_suspend(struct device *dev, int rpmflags)
420 __releases(&dev->power.lock) __acquires(&dev->power.lock)
421{
422 int (*callback)(struct device *);
423 struct device *parent = NULL;
424 int retval;
425
426 trace_rpm_suspend(dev, rpmflags);
427
428 repeat:
429 retval = rpm_check_suspend_allowed(dev);
430
431 if (retval < 0)
432 ; /* Conditions are wrong. */
433
434 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
435 else if (dev->power.runtime_status == RPM_RESUMING &&
436 !(rpmflags & RPM_ASYNC))
437 retval = -EAGAIN;
438 if (retval)
439 goto out;
440
441 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
442 if ((rpmflags & RPM_AUTO)
443 && dev->power.runtime_status != RPM_SUSPENDING) {
444 unsigned long expires = pm_runtime_autosuspend_expiration(dev);
445
446 if (expires != 0) {
447 /* Pending requests need to be canceled. */
448 dev->power.request = RPM_REQ_NONE;
449
450 /*
451 * Optimization: If the timer is already running and is
452 * set to expire at or before the autosuspend delay,
453 * avoid the overhead of resetting it. Just let it
454 * expire; pm_suspend_timer_fn() will take care of the
455 * rest.
456 */
457 if (!(dev->power.timer_expires && time_before_eq(
458 dev->power.timer_expires, expires))) {
459 dev->power.timer_expires = expires;
460 mod_timer(&dev->power.suspend_timer, expires);
461 }
462 dev->power.timer_autosuspends = 1;
463 goto out;
464 }
465 }
466
467 /* Other scheduled or pending requests need to be canceled. */
468 pm_runtime_cancel_pending(dev);
469
470 if (dev->power.runtime_status == RPM_SUSPENDING) {
471 DEFINE_WAIT(wait);
472
473 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
474 retval = -EINPROGRESS;
475 goto out;
476 }
477
478 if (dev->power.irq_safe) {
479 spin_unlock(&dev->power.lock);
480
481 cpu_relax();
482
483 spin_lock(&dev->power.lock);
484 goto repeat;
485 }
486
487 /* Wait for the other suspend running in parallel with us. */
488 for (;;) {
489 prepare_to_wait(&dev->power.wait_queue, &wait,
490 TASK_UNINTERRUPTIBLE);
491 if (dev->power.runtime_status != RPM_SUSPENDING)
492 break;
493
494 spin_unlock_irq(&dev->power.lock);
495
496 schedule();
497
498 spin_lock_irq(&dev->power.lock);
499 }
500 finish_wait(&dev->power.wait_queue, &wait);
501 goto repeat;
502 }
503
504 if (dev->power.no_callbacks)
505 goto no_callback; /* Assume success. */
506
507 /* Carry out an asynchronous or a synchronous suspend. */
508 if (rpmflags & RPM_ASYNC) {
509 dev->power.request = (rpmflags & RPM_AUTO) ?
510 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
511 if (!dev->power.request_pending) {
512 dev->power.request_pending = true;
513 queue_work(pm_wq, &dev->power.work);
514 }
515 goto out;
516 }
517
518 __update_runtime_status(dev, RPM_SUSPENDING);
519
520 callback = rpm_get_suspend_cb(dev);
521
522 retval = rpm_callback(callback, dev);
523 if (retval)
524 goto fail;
525
526 no_callback:
527 __update_runtime_status(dev, RPM_SUSPENDED);
528 pm_runtime_deactivate_timer(dev);
529
530 if (dev->parent) {
531 parent = dev->parent;
532 atomic_add_unless(&parent->power.child_count, -1, 0);
533 }
534 wake_up_all(&dev->power.wait_queue);
535
536 if (dev->power.deferred_resume) {
537 dev->power.deferred_resume = false;
538 rpm_resume(dev, 0);
539 retval = -EAGAIN;
540 goto out;
541 }
542
543 /* Maybe the parent is now able to suspend. */
544 if (parent && !parent->power.ignore_children && !dev->power.irq_safe) {
545 spin_unlock(&dev->power.lock);
546
547 spin_lock(&parent->power.lock);
548 rpm_idle(parent, RPM_ASYNC);
549 spin_unlock(&parent->power.lock);
550
551 spin_lock(&dev->power.lock);
552 }
553
554 out:
555 trace_rpm_return_int(dev, _THIS_IP_, retval);
556
557 return retval;
558
559 fail:
560 __update_runtime_status(dev, RPM_ACTIVE);
561 dev->power.deferred_resume = false;
562 wake_up_all(&dev->power.wait_queue);
563
564 if (retval == -EAGAIN || retval == -EBUSY) {
565 dev->power.runtime_error = 0;
566
567 /*
568 * If the callback routine failed an autosuspend, and
569 * if the last_busy time has been updated so that there
570 * is a new autosuspend expiration time, automatically
571 * reschedule another autosuspend.
572 */
573 if ((rpmflags & RPM_AUTO) &&
574 pm_runtime_autosuspend_expiration(dev) != 0)
575 goto repeat;
576 } else {
577 pm_runtime_cancel_pending(dev);
578 }
579 goto out;
580}
581
582/**
583 * rpm_resume - Carry out runtime resume of given device.
584 * @dev: Device to resume.
585 * @rpmflags: Flag bits.
586 *
587 * Check if the device's runtime PM status allows it to be resumed. Cancel
588 * any scheduled or pending requests. If another resume has been started
589 * earlier, either return immediately or wait for it to finish, depending on the
590 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
591 * parallel with this function, either tell the other process to resume after
592 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
593 * flag is set then queue a resume request; otherwise run the
594 * ->runtime_resume() callback directly. Queue an idle notification for the
595 * device if the resume succeeded.
596 *
597 * This function must be called under dev->power.lock with interrupts disabled.
598 */
599static int rpm_resume(struct device *dev, int rpmflags)
600 __releases(&dev->power.lock) __acquires(&dev->power.lock)
601{
602 int (*callback)(struct device *);
603 struct device *parent = NULL;
604 int retval = 0;
605
606 trace_rpm_resume(dev, rpmflags);
607
608 repeat:
609 if (dev->power.runtime_error)
610 retval = -EINVAL;
611 else if (dev->power.disable_depth == 1 && dev->power.is_suspended
612 && dev->power.runtime_status == RPM_ACTIVE)
613 retval = 1;
614 else if (dev->power.disable_depth > 0)
615 retval = -EACCES;
616 if (retval)
617 goto out;
618
619 /*
620 * Other scheduled or pending requests need to be canceled. Small
621 * optimization: If an autosuspend timer is running, leave it running
622 * rather than cancelling it now only to restart it again in the near
623 * future.
624 */
625 dev->power.request = RPM_REQ_NONE;
626 if (!dev->power.timer_autosuspends)
627 pm_runtime_deactivate_timer(dev);
628
629 if (dev->power.runtime_status == RPM_ACTIVE) {
630 retval = 1;
631 goto out;
632 }
633
634 if (dev->power.runtime_status == RPM_RESUMING
635 || dev->power.runtime_status == RPM_SUSPENDING) {
636 DEFINE_WAIT(wait);
637
638 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
639 if (dev->power.runtime_status == RPM_SUSPENDING)
640 dev->power.deferred_resume = true;
641 else
642 retval = -EINPROGRESS;
643 goto out;
644 }
645
646 if (dev->power.irq_safe) {
647 spin_unlock(&dev->power.lock);
648
649 cpu_relax();
650
651 spin_lock(&dev->power.lock);
652 goto repeat;
653 }
654
655 /* Wait for the operation carried out in parallel with us. */
656 for (;;) {
657 prepare_to_wait(&dev->power.wait_queue, &wait,
658 TASK_UNINTERRUPTIBLE);
659 if (dev->power.runtime_status != RPM_RESUMING
660 && dev->power.runtime_status != RPM_SUSPENDING)
661 break;
662
663 spin_unlock_irq(&dev->power.lock);
664
665 schedule();
666
667 spin_lock_irq(&dev->power.lock);
668 }
669 finish_wait(&dev->power.wait_queue, &wait);
670 goto repeat;
671 }
672
673 /*
674 * See if we can skip waking up the parent. This is safe only if
675 * power.no_callbacks is set, because otherwise we don't know whether
676 * the resume will actually succeed.
677 */
678 if (dev->power.no_callbacks && !parent && dev->parent) {
679 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
680 if (dev->parent->power.disable_depth > 0
681 || dev->parent->power.ignore_children
682 || dev->parent->power.runtime_status == RPM_ACTIVE) {
683 atomic_inc(&dev->parent->power.child_count);
684 spin_unlock(&dev->parent->power.lock);
685 retval = 1;
686 goto no_callback; /* Assume success. */
687 }
688 spin_unlock(&dev->parent->power.lock);
689 }
690
691 /* Carry out an asynchronous or a synchronous resume. */
692 if (rpmflags & RPM_ASYNC) {
693 dev->power.request = RPM_REQ_RESUME;
694 if (!dev->power.request_pending) {
695 dev->power.request_pending = true;
696 queue_work(pm_wq, &dev->power.work);
697 }
698 retval = 0;
699 goto out;
700 }
701
702 if (!parent && dev->parent) {
703 /*
704 * Increment the parent's usage counter and resume it if
705 * necessary. Not needed if dev is irq-safe; then the
706 * parent is permanently resumed.
707 */
708 parent = dev->parent;
709 if (dev->power.irq_safe)
710 goto skip_parent;
711 spin_unlock(&dev->power.lock);
712
713 pm_runtime_get_noresume(parent);
714
715 spin_lock(&parent->power.lock);
716 /*
717 * We can resume if the parent's runtime PM is disabled or it
718 * is set to ignore children.
719 */
720 if (!parent->power.disable_depth
721 && !parent->power.ignore_children) {
722 rpm_resume(parent, 0);
723 if (parent->power.runtime_status != RPM_ACTIVE)
724 retval = -EBUSY;
725 }
726 spin_unlock(&parent->power.lock);
727
728 spin_lock(&dev->power.lock);
729 if (retval)
730 goto out;
731 goto repeat;
732 }
733 skip_parent:
734
735 if (dev->power.no_callbacks)
736 goto no_callback; /* Assume success. */
737
738 __update_runtime_status(dev, RPM_RESUMING);
739
740 callback = rpm_get_resume_cb(dev);
741
742 retval = rpm_callback(callback, dev);
743 if (retval) {
744 __update_runtime_status(dev, RPM_SUSPENDED);
745 pm_runtime_cancel_pending(dev);
746 } else {
747 no_callback:
748 __update_runtime_status(dev, RPM_ACTIVE);
749 if (parent)
750 atomic_inc(&parent->power.child_count);
751 }
752 wake_up_all(&dev->power.wait_queue);
753
754 if (retval >= 0)
755 rpm_idle(dev, RPM_ASYNC);
756
757 out:
758 if (parent && !dev->power.irq_safe) {
759 spin_unlock_irq(&dev->power.lock);
760
761 pm_runtime_put(parent);
762
763 spin_lock_irq(&dev->power.lock);
764 }
765
766 trace_rpm_return_int(dev, _THIS_IP_, retval);
767
768 return retval;
769}
770
771/**
772 * pm_runtime_work - Universal runtime PM work function.
773 * @work: Work structure used for scheduling the execution of this function.
774 *
775 * Use @work to get the device object the work is to be done for, determine what
776 * is to be done and execute the appropriate runtime PM function.
777 */
778static void pm_runtime_work(struct work_struct *work)
779{
780 struct device *dev = container_of(work, struct device, power.work);
781 enum rpm_request req;
782
783 spin_lock_irq(&dev->power.lock);
784
785 if (!dev->power.request_pending)
786 goto out;
787
788 req = dev->power.request;
789 dev->power.request = RPM_REQ_NONE;
790 dev->power.request_pending = false;
791
792 switch (req) {
793 case RPM_REQ_NONE:
794 break;
795 case RPM_REQ_IDLE:
796 rpm_idle(dev, RPM_NOWAIT);
797 break;
798 case RPM_REQ_SUSPEND:
799 rpm_suspend(dev, RPM_NOWAIT);
800 break;
801 case RPM_REQ_AUTOSUSPEND:
802 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
803 break;
804 case RPM_REQ_RESUME:
805 rpm_resume(dev, RPM_NOWAIT);
806 break;
807 }
808
809 out:
810 spin_unlock_irq(&dev->power.lock);
811}
812
813/**
814 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
815 * @data: Device pointer passed by pm_schedule_suspend().
816 *
817 * Check if the time is right and queue a suspend request.
818 */
819static void pm_suspend_timer_fn(unsigned long data)
820{
821 struct device *dev = (struct device *)data;
822 unsigned long flags;
823 unsigned long expires;
824
825 spin_lock_irqsave(&dev->power.lock, flags);
826
827 expires = dev->power.timer_expires;
828 /* If 'expire' is after 'jiffies' we've been called too early. */
829 if (expires > 0 && !time_after(expires, jiffies)) {
830 dev->power.timer_expires = 0;
831 rpm_suspend(dev, dev->power.timer_autosuspends ?
832 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
833 }
834
835 spin_unlock_irqrestore(&dev->power.lock, flags);
836}
837
838/**
839 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
840 * @dev: Device to suspend.
841 * @delay: Time to wait before submitting a suspend request, in milliseconds.
842 */
843int pm_schedule_suspend(struct device *dev, unsigned int delay)
844{
845 unsigned long flags;
846 int retval;
847
848 spin_lock_irqsave(&dev->power.lock, flags);
849
850 if (!delay) {
851 retval = rpm_suspend(dev, RPM_ASYNC);
852 goto out;
853 }
854
855 retval = rpm_check_suspend_allowed(dev);
856 if (retval)
857 goto out;
858
859 /* Other scheduled or pending requests need to be canceled. */
860 pm_runtime_cancel_pending(dev);
861
862 dev->power.timer_expires = jiffies + msecs_to_jiffies(delay);
863 dev->power.timer_expires += !dev->power.timer_expires;
864 dev->power.timer_autosuspends = 0;
865 mod_timer(&dev->power.suspend_timer, dev->power.timer_expires);
866
867 out:
868 spin_unlock_irqrestore(&dev->power.lock, flags);
869
870 return retval;
871}
872EXPORT_SYMBOL_GPL(pm_schedule_suspend);
873
874/**
875 * __pm_runtime_idle - Entry point for runtime idle operations.
876 * @dev: Device to send idle notification for.
877 * @rpmflags: Flag bits.
878 *
879 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
880 * return immediately if it is larger than zero. Then carry out an idle
881 * notification, either synchronous or asynchronous.
882 *
883 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
884 * or if pm_runtime_irq_safe() has been called.
885 */
886int __pm_runtime_idle(struct device *dev, int rpmflags)
887{
888 unsigned long flags;
889 int retval;
890
891 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
892
893 if (rpmflags & RPM_GET_PUT) {
894 if (!atomic_dec_and_test(&dev->power.usage_count))
895 return 0;
896 }
897
898 spin_lock_irqsave(&dev->power.lock, flags);
899 retval = rpm_idle(dev, rpmflags);
900 spin_unlock_irqrestore(&dev->power.lock, flags);
901
902 return retval;
903}
904EXPORT_SYMBOL_GPL(__pm_runtime_idle);
905
906/**
907 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
908 * @dev: Device to suspend.
909 * @rpmflags: Flag bits.
910 *
911 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
912 * return immediately if it is larger than zero. Then carry out a suspend,
913 * either synchronous or asynchronous.
914 *
915 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
916 * or if pm_runtime_irq_safe() has been called.
917 */
918int __pm_runtime_suspend(struct device *dev, int rpmflags)
919{
920 unsigned long flags;
921 int retval;
922
923 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
924
925 if (rpmflags & RPM_GET_PUT) {
926 if (!atomic_dec_and_test(&dev->power.usage_count))
927 return 0;
928 }
929
930 spin_lock_irqsave(&dev->power.lock, flags);
931 retval = rpm_suspend(dev, rpmflags);
932 spin_unlock_irqrestore(&dev->power.lock, flags);
933
934 return retval;
935}
936EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
937
938/**
939 * __pm_runtime_resume - Entry point for runtime resume operations.
940 * @dev: Device to resume.
941 * @rpmflags: Flag bits.
942 *
943 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
944 * carry out a resume, either synchronous or asynchronous.
945 *
946 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
947 * or if pm_runtime_irq_safe() has been called.
948 */
949int __pm_runtime_resume(struct device *dev, int rpmflags)
950{
951 unsigned long flags;
952 int retval;
953
954 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
955
956 if (rpmflags & RPM_GET_PUT)
957 atomic_inc(&dev->power.usage_count);
958
959 spin_lock_irqsave(&dev->power.lock, flags);
960 retval = rpm_resume(dev, rpmflags);
961 spin_unlock_irqrestore(&dev->power.lock, flags);
962
963 return retval;
964}
965EXPORT_SYMBOL_GPL(__pm_runtime_resume);
966
967/**
968 * __pm_runtime_set_status - Set runtime PM status of a device.
969 * @dev: Device to handle.
970 * @status: New runtime PM status of the device.
971 *
972 * If runtime PM of the device is disabled or its power.runtime_error field is
973 * different from zero, the status may be changed either to RPM_ACTIVE, or to
974 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
975 * However, if the device has a parent and the parent is not active, and the
976 * parent's power.ignore_children flag is unset, the device's status cannot be
977 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
978 *
979 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
980 * and the device parent's counter of unsuspended children is modified to
981 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
982 * notification request for the parent is submitted.
983 */
984int __pm_runtime_set_status(struct device *dev, unsigned int status)
985{
986 struct device *parent = dev->parent;
987 unsigned long flags;
988 bool notify_parent = false;
989 int error = 0;
990
991 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
992 return -EINVAL;
993
994 spin_lock_irqsave(&dev->power.lock, flags);
995
996 if (!dev->power.runtime_error && !dev->power.disable_depth) {
997 error = -EAGAIN;
998 goto out;
999 }
1000
1001 if (dev->power.runtime_status == status)
1002 goto out_set;
1003
1004 if (status == RPM_SUSPENDED) {
1005 /* It always is possible to set the status to 'suspended'. */
1006 if (parent) {
1007 atomic_add_unless(&parent->power.child_count, -1, 0);
1008 notify_parent = !parent->power.ignore_children;
1009 }
1010 goto out_set;
1011 }
1012
1013 if (parent) {
1014 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1015
1016 /*
1017 * It is invalid to put an active child under a parent that is
1018 * not active, has runtime PM enabled and the
1019 * 'power.ignore_children' flag unset.
1020 */
1021 if (!parent->power.disable_depth
1022 && !parent->power.ignore_children
1023 && parent->power.runtime_status != RPM_ACTIVE)
1024 error = -EBUSY;
1025 else if (dev->power.runtime_status == RPM_SUSPENDED)
1026 atomic_inc(&parent->power.child_count);
1027
1028 spin_unlock(&parent->power.lock);
1029
1030 if (error)
1031 goto out;
1032 }
1033
1034 out_set:
1035 __update_runtime_status(dev, status);
1036 dev->power.runtime_error = 0;
1037 out:
1038 spin_unlock_irqrestore(&dev->power.lock, flags);
1039
1040 if (notify_parent)
1041 pm_request_idle(parent);
1042
1043 return error;
1044}
1045EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1046
1047/**
1048 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1049 * @dev: Device to handle.
1050 *
1051 * Flush all pending requests for the device from pm_wq and wait for all
1052 * runtime PM operations involving the device in progress to complete.
1053 *
1054 * Should be called under dev->power.lock with interrupts disabled.
1055 */
1056static void __pm_runtime_barrier(struct device *dev)
1057{
1058 pm_runtime_deactivate_timer(dev);
1059
1060 if (dev->power.request_pending) {
1061 dev->power.request = RPM_REQ_NONE;
1062 spin_unlock_irq(&dev->power.lock);
1063
1064 cancel_work_sync(&dev->power.work);
1065
1066 spin_lock_irq(&dev->power.lock);
1067 dev->power.request_pending = false;
1068 }
1069
1070 if (dev->power.runtime_status == RPM_SUSPENDING
1071 || dev->power.runtime_status == RPM_RESUMING
1072 || dev->power.idle_notification) {
1073 DEFINE_WAIT(wait);
1074
1075 /* Suspend, wake-up or idle notification in progress. */
1076 for (;;) {
1077 prepare_to_wait(&dev->power.wait_queue, &wait,
1078 TASK_UNINTERRUPTIBLE);
1079 if (dev->power.runtime_status != RPM_SUSPENDING
1080 && dev->power.runtime_status != RPM_RESUMING
1081 && !dev->power.idle_notification)
1082 break;
1083 spin_unlock_irq(&dev->power.lock);
1084
1085 schedule();
1086
1087 spin_lock_irq(&dev->power.lock);
1088 }
1089 finish_wait(&dev->power.wait_queue, &wait);
1090 }
1091}
1092
1093/**
1094 * pm_runtime_barrier - Flush pending requests and wait for completions.
1095 * @dev: Device to handle.
1096 *
1097 * Prevent the device from being suspended by incrementing its usage counter and
1098 * if there's a pending resume request for the device, wake the device up.
1099 * Next, make sure that all pending requests for the device have been flushed
1100 * from pm_wq and wait for all runtime PM operations involving the device in
1101 * progress to complete.
1102 *
1103 * Return value:
1104 * 1, if there was a resume request pending and the device had to be woken up,
1105 * 0, otherwise
1106 */
1107int pm_runtime_barrier(struct device *dev)
1108{
1109 int retval = 0;
1110
1111 pm_runtime_get_noresume(dev);
1112 spin_lock_irq(&dev->power.lock);
1113
1114 if (dev->power.request_pending
1115 && dev->power.request == RPM_REQ_RESUME) {
1116 rpm_resume(dev, 0);
1117 retval = 1;
1118 }
1119
1120 __pm_runtime_barrier(dev);
1121
1122 spin_unlock_irq(&dev->power.lock);
1123 pm_runtime_put_noidle(dev);
1124
1125 return retval;
1126}
1127EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1128
1129/**
1130 * __pm_runtime_disable - Disable runtime PM of a device.
1131 * @dev: Device to handle.
1132 * @check_resume: If set, check if there's a resume request for the device.
1133 *
1134 * Increment power.disable_depth for the device and if it was zero previously,
1135 * cancel all pending runtime PM requests for the device and wait for all
1136 * operations in progress to complete. The device can be either active or
1137 * suspended after its runtime PM has been disabled.
1138 *
1139 * If @check_resume is set and there's a resume request pending when
1140 * __pm_runtime_disable() is called and power.disable_depth is zero, the
1141 * function will wake up the device before disabling its runtime PM.
1142 */
1143void __pm_runtime_disable(struct device *dev, bool check_resume)
1144{
1145 spin_lock_irq(&dev->power.lock);
1146
1147 if (dev->power.disable_depth > 0) {
1148 dev->power.disable_depth++;
1149 goto out;
1150 }
1151
1152 /*
1153 * Wake up the device if there's a resume request pending, because that
1154 * means there probably is some I/O to process and disabling runtime PM
1155 * shouldn't prevent the device from processing the I/O.
1156 */
1157 if (check_resume && dev->power.request_pending
1158 && dev->power.request == RPM_REQ_RESUME) {
1159 /*
1160 * Prevent suspends and idle notifications from being carried
1161 * out after we have woken up the device.
1162 */
1163 pm_runtime_get_noresume(dev);
1164
1165 rpm_resume(dev, 0);
1166
1167 pm_runtime_put_noidle(dev);
1168 }
1169
1170 if (!dev->power.disable_depth++)
1171 __pm_runtime_barrier(dev);
1172
1173 out:
1174 spin_unlock_irq(&dev->power.lock);
1175}
1176EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1177
1178/**
1179 * pm_runtime_enable - Enable runtime PM of a device.
1180 * @dev: Device to handle.
1181 */
1182void pm_runtime_enable(struct device *dev)
1183{
1184 unsigned long flags;
1185
1186 spin_lock_irqsave(&dev->power.lock, flags);
1187
1188 if (dev->power.disable_depth > 0)
1189 dev->power.disable_depth--;
1190 else
1191 dev_warn(dev, "Unbalanced %s!\n", __func__);
1192
1193 spin_unlock_irqrestore(&dev->power.lock, flags);
1194}
1195EXPORT_SYMBOL_GPL(pm_runtime_enable);
1196
1197/**
1198 * pm_runtime_forbid - Block runtime PM of a device.
1199 * @dev: Device to handle.
1200 *
1201 * Increase the device's usage count and clear its power.runtime_auto flag,
1202 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1203 * for it.
1204 */
1205void pm_runtime_forbid(struct device *dev)
1206{
1207 spin_lock_irq(&dev->power.lock);
1208 if (!dev->power.runtime_auto)
1209 goto out;
1210
1211 dev->power.runtime_auto = false;
1212 atomic_inc(&dev->power.usage_count);
1213 rpm_resume(dev, 0);
1214
1215 out:
1216 spin_unlock_irq(&dev->power.lock);
1217}
1218EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1219
1220/**
1221 * pm_runtime_allow - Unblock runtime PM of a device.
1222 * @dev: Device to handle.
1223 *
1224 * Decrease the device's usage count and set its power.runtime_auto flag.
1225 */
1226void pm_runtime_allow(struct device *dev)
1227{
1228 spin_lock_irq(&dev->power.lock);
1229 if (dev->power.runtime_auto)
1230 goto out;
1231
1232 dev->power.runtime_auto = true;
1233 if (atomic_dec_and_test(&dev->power.usage_count))
1234 rpm_idle(dev, RPM_AUTO);
1235
1236 out:
1237 spin_unlock_irq(&dev->power.lock);
1238}
1239EXPORT_SYMBOL_GPL(pm_runtime_allow);
1240
1241/**
1242 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1243 * @dev: Device to handle.
1244 *
1245 * Set the power.no_callbacks flag, which tells the PM core that this
1246 * device is power-managed through its parent and has no runtime PM
1247 * callbacks of its own. The runtime sysfs attributes will be removed.
1248 */
1249void pm_runtime_no_callbacks(struct device *dev)
1250{
1251 spin_lock_irq(&dev->power.lock);
1252 dev->power.no_callbacks = 1;
1253 spin_unlock_irq(&dev->power.lock);
1254 if (device_is_registered(dev))
1255 rpm_sysfs_remove(dev);
1256}
1257EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1258
1259/**
1260 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1261 * @dev: Device to handle
1262 *
1263 * Set the power.irq_safe flag, which tells the PM core that the
1264 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1265 * always be invoked with the spinlock held and interrupts disabled. It also
1266 * causes the parent's usage counter to be permanently incremented, preventing
1267 * the parent from runtime suspending -- otherwise an irq-safe child might have
1268 * to wait for a non-irq-safe parent.
1269 */
1270void pm_runtime_irq_safe(struct device *dev)
1271{
1272 if (dev->parent)
1273 pm_runtime_get_sync(dev->parent);
1274 spin_lock_irq(&dev->power.lock);
1275 dev->power.irq_safe = 1;
1276 spin_unlock_irq(&dev->power.lock);
1277}
1278EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1279
1280/**
1281 * update_autosuspend - Handle a change to a device's autosuspend settings.
1282 * @dev: Device to handle.
1283 * @old_delay: The former autosuspend_delay value.
1284 * @old_use: The former use_autosuspend value.
1285 *
1286 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1287 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1288 *
1289 * This function must be called under dev->power.lock with interrupts disabled.
1290 */
1291static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1292{
1293 int delay = dev->power.autosuspend_delay;
1294
1295 /* Should runtime suspend be prevented now? */
1296 if (dev->power.use_autosuspend && delay < 0) {
1297
1298 /* If it used to be allowed then prevent it. */
1299 if (!old_use || old_delay >= 0) {
1300 atomic_inc(&dev->power.usage_count);
1301 rpm_resume(dev, 0);
1302 }
1303 }
1304
1305 /* Runtime suspend should be allowed now. */
1306 else {
1307
1308 /* If it used to be prevented then allow it. */
1309 if (old_use && old_delay < 0)
1310 atomic_dec(&dev->power.usage_count);
1311
1312 /* Maybe we can autosuspend now. */
1313 rpm_idle(dev, RPM_AUTO);
1314 }
1315}
1316
1317/**
1318 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1319 * @dev: Device to handle.
1320 * @delay: Value of the new delay in milliseconds.
1321 *
1322 * Set the device's power.autosuspend_delay value. If it changes to negative
1323 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1324 * changes the other way, allow runtime suspends.
1325 */
1326void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1327{
1328 int old_delay, old_use;
1329
1330 spin_lock_irq(&dev->power.lock);
1331 old_delay = dev->power.autosuspend_delay;
1332 old_use = dev->power.use_autosuspend;
1333 dev->power.autosuspend_delay = delay;
1334 update_autosuspend(dev, old_delay, old_use);
1335 spin_unlock_irq(&dev->power.lock);
1336}
1337EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1338
1339/**
1340 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1341 * @dev: Device to handle.
1342 * @use: New value for use_autosuspend.
1343 *
1344 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1345 * suspends as needed.
1346 */
1347void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1348{
1349 int old_delay, old_use;
1350
1351 spin_lock_irq(&dev->power.lock);
1352 old_delay = dev->power.autosuspend_delay;
1353 old_use = dev->power.use_autosuspend;
1354 dev->power.use_autosuspend = use;
1355 update_autosuspend(dev, old_delay, old_use);
1356 spin_unlock_irq(&dev->power.lock);
1357}
1358EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1359
1360/**
1361 * pm_runtime_init - Initialize runtime PM fields in given device object.
1362 * @dev: Device object to initialize.
1363 */
1364void pm_runtime_init(struct device *dev)
1365{
1366 dev->power.runtime_status = RPM_SUSPENDED;
1367 dev->power.idle_notification = false;
1368
1369 dev->power.disable_depth = 1;
1370 atomic_set(&dev->power.usage_count, 0);
1371
1372 dev->power.runtime_error = 0;
1373
1374 atomic_set(&dev->power.child_count, 0);
1375 pm_suspend_ignore_children(dev, false);
1376 dev->power.runtime_auto = true;
1377
1378 dev->power.request_pending = false;
1379 dev->power.request = RPM_REQ_NONE;
1380 dev->power.deferred_resume = false;
1381 dev->power.accounting_timestamp = jiffies;
1382 INIT_WORK(&dev->power.work, pm_runtime_work);
1383
1384 dev->power.timer_expires = 0;
1385 setup_timer(&dev->power.suspend_timer, pm_suspend_timer_fn,
1386 (unsigned long)dev);
1387
1388 init_waitqueue_head(&dev->power.wait_queue);
1389}
1390
1391/**
1392 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1393 * @dev: Device object being removed from device hierarchy.
1394 */
1395void pm_runtime_remove(struct device *dev)
1396{
1397 __pm_runtime_disable(dev, false);
1398
1399 /* Change the status back to 'suspended' to match the initial status. */
1400 if (dev->power.runtime_status == RPM_ACTIVE)
1401 pm_runtime_set_suspended(dev);
1402 if (dev->power.irq_safe && dev->parent)
1403 pm_runtime_put(dev->parent);
1404}
1405#endif
1406
1407/**
1408 * pm_runtime_force_suspend - Force a device into suspend state if needed.
1409 * @dev: Device to suspend.
1410 *
1411 * Disable runtime PM so we safely can check the device's runtime PM status and
1412 * if it is active, invoke it's .runtime_suspend callback to bring it into
1413 * suspend state. Keep runtime PM disabled to preserve the state unless we
1414 * encounter errors.
1415 *
1416 * Typically this function may be invoked from a system suspend callback to make
1417 * sure the device is put into low power state.
1418 */
1419int pm_runtime_force_suspend(struct device *dev)
1420{
1421 int (*callback)(struct device *);
1422 int ret = 0;
1423
1424 pm_runtime_disable(dev);
1425
1426 /*
1427 * Note that pm_runtime_status_suspended() returns false while
1428 * !CONFIG_PM_RUNTIME, which means the device will be put into low
1429 * power state.
1430 */
1431 if (pm_runtime_status_suspended(dev))
1432 return 0;
1433
1434 callback = rpm_get_suspend_cb(dev);
1435
1436 if (!callback) {
1437 ret = -ENOSYS;
1438 goto err;
1439 }
1440
1441 ret = callback(dev);
1442 if (ret)
1443 goto err;
1444
1445 pm_runtime_set_suspended(dev);
1446 return 0;
1447err:
1448 pm_runtime_enable(dev);
1449 return ret;
1450}
1451EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1452
1453/**
1454 * pm_runtime_force_resume - Force a device into resume state.
1455 * @dev: Device to resume.
1456 *
1457 * Prior invoking this function we expect the user to have brought the device
1458 * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1459 * those actions and brings the device into full power. We update the runtime PM
1460 * status and re-enables runtime PM.
1461 *
1462 * Typically this function may be invoked from a system resume callback to make
1463 * sure the device is put into full power state.
1464 */
1465int pm_runtime_force_resume(struct device *dev)
1466{
1467 int (*callback)(struct device *);
1468 int ret = 0;
1469
1470 callback = rpm_get_resume_cb(dev);
1471
1472 if (!callback) {
1473 ret = -ENOSYS;
1474 goto out;
1475 }
1476
1477 ret = callback(dev);
1478 if (ret)
1479 goto out;
1480
1481 pm_runtime_set_active(dev);
1482 pm_runtime_mark_last_busy(dev);
1483out:
1484 pm_runtime_enable(dev);
1485 return ret;
1486}
1487EXPORT_SYMBOL_GPL(pm_runtime_force_resume);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/power/runtime.c - Helper functions for device runtime PM
4 *
5 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
6 * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu>
7 */
8#include <linux/sched/mm.h>
9#include <linux/ktime.h>
10#include <linux/hrtimer.h>
11#include <linux/export.h>
12#include <linux/pm_runtime.h>
13#include <linux/pm_wakeirq.h>
14#include <linux/rculist.h>
15#include <trace/events/rpm.h>
16
17#include "../base.h"
18#include "power.h"
19
20typedef int (*pm_callback_t)(struct device *);
21
22static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
23{
24 pm_callback_t cb;
25 const struct dev_pm_ops *ops;
26
27 if (dev->pm_domain)
28 ops = &dev->pm_domain->ops;
29 else if (dev->type && dev->type->pm)
30 ops = dev->type->pm;
31 else if (dev->class && dev->class->pm)
32 ops = dev->class->pm;
33 else if (dev->bus && dev->bus->pm)
34 ops = dev->bus->pm;
35 else
36 ops = NULL;
37
38 if (ops)
39 cb = *(pm_callback_t *)((void *)ops + cb_offset);
40 else
41 cb = NULL;
42
43 if (!cb && dev->driver && dev->driver->pm)
44 cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
45
46 return cb;
47}
48
49#define RPM_GET_CALLBACK(dev, callback) \
50 __rpm_get_callback(dev, offsetof(struct dev_pm_ops, callback))
51
52static int rpm_resume(struct device *dev, int rpmflags);
53static int rpm_suspend(struct device *dev, int rpmflags);
54
55/**
56 * update_pm_runtime_accounting - Update the time accounting of power states
57 * @dev: Device to update the accounting for
58 *
59 * In order to be able to have time accounting of the various power states
60 * (as used by programs such as PowerTOP to show the effectiveness of runtime
61 * PM), we need to track the time spent in each state.
62 * update_pm_runtime_accounting must be called each time before the
63 * runtime_status field is updated, to account the time in the old state
64 * correctly.
65 */
66static void update_pm_runtime_accounting(struct device *dev)
67{
68 u64 now, last, delta;
69
70 if (dev->power.disable_depth > 0)
71 return;
72
73 last = dev->power.accounting_timestamp;
74
75 now = ktime_get_mono_fast_ns();
76 dev->power.accounting_timestamp = now;
77
78 /*
79 * Because ktime_get_mono_fast_ns() is not monotonic during
80 * timekeeping updates, ensure that 'now' is after the last saved
81 * timesptamp.
82 */
83 if (now < last)
84 return;
85
86 delta = now - last;
87
88 if (dev->power.runtime_status == RPM_SUSPENDED)
89 dev->power.suspended_time += delta;
90 else
91 dev->power.active_time += delta;
92}
93
94static void __update_runtime_status(struct device *dev, enum rpm_status status)
95{
96 update_pm_runtime_accounting(dev);
97 trace_rpm_status(dev, status);
98 dev->power.runtime_status = status;
99}
100
101static 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
116u64 pm_runtime_active_time(struct device *dev)
117{
118 return rpm_get_accounted_time(dev, false);
119}
120
121u64 pm_runtime_suspended_time(struct device *dev)
122{
123 return rpm_get_accounted_time(dev, true);
124}
125EXPORT_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 */
131static 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 */
143static 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 */
165u64 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}
184EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
185
186static 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 */
219void 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, dev_memalloc_noio)))
249 break;
250 }
251 mutex_unlock(&dev_hotplug_mutex);
252}
253EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio);
254
255/**
256 * rpm_check_suspend_allowed - Test whether a device may be suspended.
257 * @dev: Device to test.
258 */
259static int rpm_check_suspend_allowed(struct device *dev)
260{
261 int retval = 0;
262
263 if (dev->power.runtime_error)
264 retval = -EINVAL;
265 else if (dev->power.disable_depth > 0)
266 retval = -EACCES;
267 else if (atomic_read(&dev->power.usage_count))
268 retval = -EAGAIN;
269 else if (!dev->power.ignore_children && atomic_read(&dev->power.child_count))
270 retval = -EBUSY;
271
272 /* Pending resume requests take precedence over suspends. */
273 else if ((dev->power.deferred_resume &&
274 dev->power.runtime_status == RPM_SUSPENDING) ||
275 (dev->power.request_pending && dev->power.request == RPM_REQ_RESUME))
276 retval = -EAGAIN;
277 else if (__dev_pm_qos_resume_latency(dev) == 0)
278 retval = -EPERM;
279 else if (dev->power.runtime_status == RPM_SUSPENDED)
280 retval = 1;
281
282 return retval;
283}
284
285static int rpm_get_suppliers(struct device *dev)
286{
287 struct device_link *link;
288
289 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
290 device_links_read_lock_held()) {
291 int retval;
292
293 if (!(link->flags & DL_FLAG_PM_RUNTIME))
294 continue;
295
296 retval = pm_runtime_get_sync(link->supplier);
297 /* Ignore suppliers with disabled runtime PM. */
298 if (retval < 0 && retval != -EACCES) {
299 pm_runtime_put_noidle(link->supplier);
300 return retval;
301 }
302 refcount_inc(&link->rpm_active);
303 }
304 return 0;
305}
306
307/**
308 * pm_runtime_release_supplier - Drop references to device link's supplier.
309 * @link: Target device link.
310 *
311 * Drop all runtime PM references associated with @link to its supplier device.
312 */
313void pm_runtime_release_supplier(struct device_link *link)
314{
315 struct device *supplier = link->supplier;
316
317 /*
318 * The additional power.usage_count check is a safety net in case
319 * the rpm_active refcount becomes saturated, in which case
320 * refcount_dec_not_one() would return true forever, but it is not
321 * strictly necessary.
322 */
323 while (refcount_dec_not_one(&link->rpm_active) &&
324 atomic_read(&supplier->power.usage_count) > 0)
325 pm_runtime_put_noidle(supplier);
326}
327
328static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
329{
330 struct device_link *link;
331
332 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
333 device_links_read_lock_held()) {
334 pm_runtime_release_supplier(link);
335 if (try_to_suspend)
336 pm_request_idle(link->supplier);
337 }
338}
339
340static void rpm_put_suppliers(struct device *dev)
341{
342 __rpm_put_suppliers(dev, true);
343}
344
345static void rpm_suspend_suppliers(struct device *dev)
346{
347 struct device_link *link;
348 int idx = device_links_read_lock();
349
350 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
351 device_links_read_lock_held())
352 pm_request_idle(link->supplier);
353
354 device_links_read_unlock(idx);
355}
356
357/**
358 * __rpm_callback - Run a given runtime PM callback for a given device.
359 * @cb: Runtime PM callback to run.
360 * @dev: Device to run the callback for.
361 */
362static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
363 __releases(&dev->power.lock) __acquires(&dev->power.lock)
364{
365 int retval = 0, idx;
366 bool use_links = dev->power.links_count > 0;
367
368 if (dev->power.irq_safe) {
369 spin_unlock(&dev->power.lock);
370 } else {
371 spin_unlock_irq(&dev->power.lock);
372
373 /*
374 * Resume suppliers if necessary.
375 *
376 * The device's runtime PM status cannot change until this
377 * routine returns, so it is safe to read the status outside of
378 * the lock.
379 */
380 if (use_links && dev->power.runtime_status == RPM_RESUMING) {
381 idx = device_links_read_lock();
382
383 retval = rpm_get_suppliers(dev);
384 if (retval) {
385 rpm_put_suppliers(dev);
386 goto fail;
387 }
388
389 device_links_read_unlock(idx);
390 }
391 }
392
393 if (cb)
394 retval = cb(dev);
395
396 if (dev->power.irq_safe) {
397 spin_lock(&dev->power.lock);
398 } else {
399 /*
400 * If the device is suspending and the callback has returned
401 * success, drop the usage counters of the suppliers that have
402 * been reference counted on its resume.
403 *
404 * Do that if resume fails too.
405 */
406 if (use_links &&
407 ((dev->power.runtime_status == RPM_SUSPENDING && !retval) ||
408 (dev->power.runtime_status == RPM_RESUMING && retval))) {
409 idx = device_links_read_lock();
410
411 __rpm_put_suppliers(dev, false);
412
413fail:
414 device_links_read_unlock(idx);
415 }
416
417 spin_lock_irq(&dev->power.lock);
418 }
419
420 return retval;
421}
422
423/**
424 * rpm_callback - Run a given runtime PM callback for a given device.
425 * @cb: Runtime PM callback to run.
426 * @dev: Device to run the callback for.
427 */
428static int rpm_callback(int (*cb)(struct device *), struct device *dev)
429{
430 int retval;
431
432 if (dev->power.memalloc_noio) {
433 unsigned int noio_flag;
434
435 /*
436 * Deadlock might be caused if memory allocation with
437 * GFP_KERNEL happens inside runtime_suspend and
438 * runtime_resume callbacks of one block device's
439 * ancestor or the block device itself. Network
440 * device might be thought as part of iSCSI block
441 * device, so network device and its ancestor should
442 * be marked as memalloc_noio too.
443 */
444 noio_flag = memalloc_noio_save();
445 retval = __rpm_callback(cb, dev);
446 memalloc_noio_restore(noio_flag);
447 } else {
448 retval = __rpm_callback(cb, dev);
449 }
450
451 dev->power.runtime_error = retval;
452 return retval != -EACCES ? retval : -EIO;
453}
454
455/**
456 * rpm_idle - Notify device bus type if the device can be suspended.
457 * @dev: Device to notify the bus type about.
458 * @rpmflags: Flag bits.
459 *
460 * Check if the device's runtime PM status allows it to be suspended. If
461 * another idle notification has been started earlier, return immediately. If
462 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
463 * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
464 * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
465 *
466 * This function must be called under dev->power.lock with interrupts disabled.
467 */
468static int rpm_idle(struct device *dev, int rpmflags)
469{
470 int (*callback)(struct device *);
471 int retval;
472
473 trace_rpm_idle(dev, rpmflags);
474 retval = rpm_check_suspend_allowed(dev);
475 if (retval < 0)
476 ; /* Conditions are wrong. */
477
478 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
479 else if (dev->power.runtime_status != RPM_ACTIVE)
480 retval = -EAGAIN;
481
482 /*
483 * Any pending request other than an idle notification takes
484 * precedence over us, except that the timer may be running.
485 */
486 else if (dev->power.request_pending &&
487 dev->power.request > RPM_REQ_IDLE)
488 retval = -EAGAIN;
489
490 /* Act as though RPM_NOWAIT is always set. */
491 else if (dev->power.idle_notification)
492 retval = -EINPROGRESS;
493
494 if (retval)
495 goto out;
496
497 /* Pending requests need to be canceled. */
498 dev->power.request = RPM_REQ_NONE;
499
500 callback = RPM_GET_CALLBACK(dev, runtime_idle);
501
502 /* If no callback assume success. */
503 if (!callback || dev->power.no_callbacks)
504 goto out;
505
506 /* Carry out an asynchronous or a synchronous idle notification. */
507 if (rpmflags & RPM_ASYNC) {
508 dev->power.request = RPM_REQ_IDLE;
509 if (!dev->power.request_pending) {
510 dev->power.request_pending = true;
511 queue_work(pm_wq, &dev->power.work);
512 }
513 trace_rpm_return_int(dev, _THIS_IP_, 0);
514 return 0;
515 }
516
517 dev->power.idle_notification = true;
518
519 if (dev->power.irq_safe)
520 spin_unlock(&dev->power.lock);
521 else
522 spin_unlock_irq(&dev->power.lock);
523
524 retval = callback(dev);
525
526 if (dev->power.irq_safe)
527 spin_lock(&dev->power.lock);
528 else
529 spin_lock_irq(&dev->power.lock);
530
531 dev->power.idle_notification = false;
532 wake_up_all(&dev->power.wait_queue);
533
534 out:
535 trace_rpm_return_int(dev, _THIS_IP_, retval);
536 return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
537}
538
539/**
540 * rpm_suspend - Carry out runtime suspend of given device.
541 * @dev: Device to suspend.
542 * @rpmflags: Flag bits.
543 *
544 * Check if the device's runtime PM status allows it to be suspended.
545 * Cancel a pending idle notification, autosuspend or suspend. If
546 * another suspend has been started earlier, either return immediately
547 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
548 * flags. If the RPM_ASYNC flag is set then queue a suspend request;
549 * otherwise run the ->runtime_suspend() callback directly. When
550 * ->runtime_suspend succeeded, if a deferred resume was requested while
551 * the callback was running then carry it out, otherwise send an idle
552 * notification for its parent (if the suspend succeeded and both
553 * ignore_children of parent->power and irq_safe of dev->power are not set).
554 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
555 * flag is set and the next autosuspend-delay expiration time is in the
556 * future, schedule another autosuspend attempt.
557 *
558 * This function must be called under dev->power.lock with interrupts disabled.
559 */
560static int rpm_suspend(struct device *dev, int rpmflags)
561 __releases(&dev->power.lock) __acquires(&dev->power.lock)
562{
563 int (*callback)(struct device *);
564 struct device *parent = NULL;
565 int retval;
566
567 trace_rpm_suspend(dev, rpmflags);
568
569 repeat:
570 retval = rpm_check_suspend_allowed(dev);
571 if (retval < 0)
572 goto out; /* Conditions are wrong. */
573
574 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
575 if (dev->power.runtime_status == RPM_RESUMING && !(rpmflags & RPM_ASYNC))
576 retval = -EAGAIN;
577
578 if (retval)
579 goto out;
580
581 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
582 if ((rpmflags & RPM_AUTO) && dev->power.runtime_status != RPM_SUSPENDING) {
583 u64 expires = pm_runtime_autosuspend_expiration(dev);
584
585 if (expires != 0) {
586 /* Pending requests need to be canceled. */
587 dev->power.request = RPM_REQ_NONE;
588
589 /*
590 * Optimization: If the timer is already running and is
591 * set to expire at or before the autosuspend delay,
592 * avoid the overhead of resetting it. Just let it
593 * expire; pm_suspend_timer_fn() will take care of the
594 * rest.
595 */
596 if (!(dev->power.timer_expires &&
597 dev->power.timer_expires <= expires)) {
598 /*
599 * We add a slack of 25% to gather wakeups
600 * without sacrificing the granularity.
601 */
602 u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) *
603 (NSEC_PER_MSEC >> 2);
604
605 dev->power.timer_expires = expires;
606 hrtimer_start_range_ns(&dev->power.suspend_timer,
607 ns_to_ktime(expires),
608 slack,
609 HRTIMER_MODE_ABS);
610 }
611 dev->power.timer_autosuspends = 1;
612 goto out;
613 }
614 }
615
616 /* Other scheduled or pending requests need to be canceled. */
617 pm_runtime_cancel_pending(dev);
618
619 if (dev->power.runtime_status == RPM_SUSPENDING) {
620 DEFINE_WAIT(wait);
621
622 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
623 retval = -EINPROGRESS;
624 goto out;
625 }
626
627 if (dev->power.irq_safe) {
628 spin_unlock(&dev->power.lock);
629
630 cpu_relax();
631
632 spin_lock(&dev->power.lock);
633 goto repeat;
634 }
635
636 /* Wait for the other suspend running in parallel with us. */
637 for (;;) {
638 prepare_to_wait(&dev->power.wait_queue, &wait,
639 TASK_UNINTERRUPTIBLE);
640 if (dev->power.runtime_status != RPM_SUSPENDING)
641 break;
642
643 spin_unlock_irq(&dev->power.lock);
644
645 schedule();
646
647 spin_lock_irq(&dev->power.lock);
648 }
649 finish_wait(&dev->power.wait_queue, &wait);
650 goto repeat;
651 }
652
653 if (dev->power.no_callbacks)
654 goto no_callback; /* Assume success. */
655
656 /* Carry out an asynchronous or a synchronous suspend. */
657 if (rpmflags & RPM_ASYNC) {
658 dev->power.request = (rpmflags & RPM_AUTO) ?
659 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
660 if (!dev->power.request_pending) {
661 dev->power.request_pending = true;
662 queue_work(pm_wq, &dev->power.work);
663 }
664 goto out;
665 }
666
667 __update_runtime_status(dev, RPM_SUSPENDING);
668
669 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
670
671 dev_pm_enable_wake_irq_check(dev, true);
672 retval = rpm_callback(callback, dev);
673 if (retval)
674 goto fail;
675
676 dev_pm_enable_wake_irq_complete(dev);
677
678 no_callback:
679 __update_runtime_status(dev, RPM_SUSPENDED);
680 pm_runtime_deactivate_timer(dev);
681
682 if (dev->parent) {
683 parent = dev->parent;
684 atomic_add_unless(&parent->power.child_count, -1, 0);
685 }
686 wake_up_all(&dev->power.wait_queue);
687
688 if (dev->power.deferred_resume) {
689 dev->power.deferred_resume = false;
690 rpm_resume(dev, 0);
691 retval = -EAGAIN;
692 goto out;
693 }
694
695 if (dev->power.irq_safe)
696 goto out;
697
698 /* Maybe the parent is now able to suspend. */
699 if (parent && !parent->power.ignore_children) {
700 spin_unlock(&dev->power.lock);
701
702 spin_lock(&parent->power.lock);
703 rpm_idle(parent, RPM_ASYNC);
704 spin_unlock(&parent->power.lock);
705
706 spin_lock(&dev->power.lock);
707 }
708 /* Maybe the suppliers are now able to suspend. */
709 if (dev->power.links_count > 0) {
710 spin_unlock_irq(&dev->power.lock);
711
712 rpm_suspend_suppliers(dev);
713
714 spin_lock_irq(&dev->power.lock);
715 }
716
717 out:
718 trace_rpm_return_int(dev, _THIS_IP_, retval);
719
720 return retval;
721
722 fail:
723 dev_pm_disable_wake_irq_check(dev, true);
724 __update_runtime_status(dev, RPM_ACTIVE);
725 dev->power.deferred_resume = false;
726 wake_up_all(&dev->power.wait_queue);
727
728 if (retval == -EAGAIN || retval == -EBUSY) {
729 dev->power.runtime_error = 0;
730
731 /*
732 * If the callback routine failed an autosuspend, and
733 * if the last_busy time has been updated so that there
734 * is a new autosuspend expiration time, automatically
735 * reschedule another autosuspend.
736 */
737 if ((rpmflags & RPM_AUTO) &&
738 pm_runtime_autosuspend_expiration(dev) != 0)
739 goto repeat;
740 } else {
741 pm_runtime_cancel_pending(dev);
742 }
743 goto out;
744}
745
746/**
747 * rpm_resume - Carry out runtime resume of given device.
748 * @dev: Device to resume.
749 * @rpmflags: Flag bits.
750 *
751 * Check if the device's runtime PM status allows it to be resumed. Cancel
752 * any scheduled or pending requests. If another resume has been started
753 * earlier, either return immediately or wait for it to finish, depending on the
754 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
755 * parallel with this function, either tell the other process to resume after
756 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
757 * flag is set then queue a resume request; otherwise run the
758 * ->runtime_resume() callback directly. Queue an idle notification for the
759 * device if the resume succeeded.
760 *
761 * This function must be called under dev->power.lock with interrupts disabled.
762 */
763static int rpm_resume(struct device *dev, int rpmflags)
764 __releases(&dev->power.lock) __acquires(&dev->power.lock)
765{
766 int (*callback)(struct device *);
767 struct device *parent = NULL;
768 int retval = 0;
769
770 trace_rpm_resume(dev, rpmflags);
771
772 repeat:
773 if (dev->power.runtime_error) {
774 retval = -EINVAL;
775 } else if (dev->power.disable_depth > 0) {
776 if (dev->power.runtime_status == RPM_ACTIVE &&
777 dev->power.last_status == RPM_ACTIVE)
778 retval = 1;
779 else
780 retval = -EACCES;
781 }
782 if (retval)
783 goto out;
784
785 /*
786 * Other scheduled or pending requests need to be canceled. Small
787 * optimization: If an autosuspend timer is running, leave it running
788 * rather than cancelling it now only to restart it again in the near
789 * future.
790 */
791 dev->power.request = RPM_REQ_NONE;
792 if (!dev->power.timer_autosuspends)
793 pm_runtime_deactivate_timer(dev);
794
795 if (dev->power.runtime_status == RPM_ACTIVE) {
796 retval = 1;
797 goto out;
798 }
799
800 if (dev->power.runtime_status == RPM_RESUMING ||
801 dev->power.runtime_status == RPM_SUSPENDING) {
802 DEFINE_WAIT(wait);
803
804 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
805 if (dev->power.runtime_status == RPM_SUSPENDING) {
806 dev->power.deferred_resume = true;
807 if (rpmflags & RPM_NOWAIT)
808 retval = -EINPROGRESS;
809 } else {
810 retval = -EINPROGRESS;
811 }
812 goto out;
813 }
814
815 if (dev->power.irq_safe) {
816 spin_unlock(&dev->power.lock);
817
818 cpu_relax();
819
820 spin_lock(&dev->power.lock);
821 goto repeat;
822 }
823
824 /* Wait for the operation carried out in parallel with us. */
825 for (;;) {
826 prepare_to_wait(&dev->power.wait_queue, &wait,
827 TASK_UNINTERRUPTIBLE);
828 if (dev->power.runtime_status != RPM_RESUMING &&
829 dev->power.runtime_status != RPM_SUSPENDING)
830 break;
831
832 spin_unlock_irq(&dev->power.lock);
833
834 schedule();
835
836 spin_lock_irq(&dev->power.lock);
837 }
838 finish_wait(&dev->power.wait_queue, &wait);
839 goto repeat;
840 }
841
842 /*
843 * See if we can skip waking up the parent. This is safe only if
844 * power.no_callbacks is set, because otherwise we don't know whether
845 * the resume will actually succeed.
846 */
847 if (dev->power.no_callbacks && !parent && dev->parent) {
848 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
849 if (dev->parent->power.disable_depth > 0 ||
850 dev->parent->power.ignore_children ||
851 dev->parent->power.runtime_status == RPM_ACTIVE) {
852 atomic_inc(&dev->parent->power.child_count);
853 spin_unlock(&dev->parent->power.lock);
854 retval = 1;
855 goto no_callback; /* Assume success. */
856 }
857 spin_unlock(&dev->parent->power.lock);
858 }
859
860 /* Carry out an asynchronous or a synchronous resume. */
861 if (rpmflags & RPM_ASYNC) {
862 dev->power.request = RPM_REQ_RESUME;
863 if (!dev->power.request_pending) {
864 dev->power.request_pending = true;
865 queue_work(pm_wq, &dev->power.work);
866 }
867 retval = 0;
868 goto out;
869 }
870
871 if (!parent && dev->parent) {
872 /*
873 * Increment the parent's usage counter and resume it if
874 * necessary. Not needed if dev is irq-safe; then the
875 * parent is permanently resumed.
876 */
877 parent = dev->parent;
878 if (dev->power.irq_safe)
879 goto skip_parent;
880
881 spin_unlock(&dev->power.lock);
882
883 pm_runtime_get_noresume(parent);
884
885 spin_lock(&parent->power.lock);
886 /*
887 * Resume the parent if it has runtime PM enabled and not been
888 * set to ignore its children.
889 */
890 if (!parent->power.disable_depth &&
891 !parent->power.ignore_children) {
892 rpm_resume(parent, 0);
893 if (parent->power.runtime_status != RPM_ACTIVE)
894 retval = -EBUSY;
895 }
896 spin_unlock(&parent->power.lock);
897
898 spin_lock(&dev->power.lock);
899 if (retval)
900 goto out;
901
902 goto repeat;
903 }
904 skip_parent:
905
906 if (dev->power.no_callbacks)
907 goto no_callback; /* Assume success. */
908
909 __update_runtime_status(dev, RPM_RESUMING);
910
911 callback = RPM_GET_CALLBACK(dev, runtime_resume);
912
913 dev_pm_disable_wake_irq_check(dev, false);
914 retval = rpm_callback(callback, dev);
915 if (retval) {
916 __update_runtime_status(dev, RPM_SUSPENDED);
917 pm_runtime_cancel_pending(dev);
918 dev_pm_enable_wake_irq_check(dev, false);
919 } else {
920 no_callback:
921 __update_runtime_status(dev, RPM_ACTIVE);
922 pm_runtime_mark_last_busy(dev);
923 if (parent)
924 atomic_inc(&parent->power.child_count);
925 }
926 wake_up_all(&dev->power.wait_queue);
927
928 if (retval >= 0)
929 rpm_idle(dev, RPM_ASYNC);
930
931 out:
932 if (parent && !dev->power.irq_safe) {
933 spin_unlock_irq(&dev->power.lock);
934
935 pm_runtime_put(parent);
936
937 spin_lock_irq(&dev->power.lock);
938 }
939
940 trace_rpm_return_int(dev, _THIS_IP_, retval);
941
942 return retval;
943}
944
945/**
946 * pm_runtime_work - Universal runtime PM work function.
947 * @work: Work structure used for scheduling the execution of this function.
948 *
949 * Use @work to get the device object the work is to be done for, determine what
950 * is to be done and execute the appropriate runtime PM function.
951 */
952static void pm_runtime_work(struct work_struct *work)
953{
954 struct device *dev = container_of(work, struct device, power.work);
955 enum rpm_request req;
956
957 spin_lock_irq(&dev->power.lock);
958
959 if (!dev->power.request_pending)
960 goto out;
961
962 req = dev->power.request;
963 dev->power.request = RPM_REQ_NONE;
964 dev->power.request_pending = false;
965
966 switch (req) {
967 case RPM_REQ_NONE:
968 break;
969 case RPM_REQ_IDLE:
970 rpm_idle(dev, RPM_NOWAIT);
971 break;
972 case RPM_REQ_SUSPEND:
973 rpm_suspend(dev, RPM_NOWAIT);
974 break;
975 case RPM_REQ_AUTOSUSPEND:
976 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
977 break;
978 case RPM_REQ_RESUME:
979 rpm_resume(dev, RPM_NOWAIT);
980 break;
981 }
982
983 out:
984 spin_unlock_irq(&dev->power.lock);
985}
986
987/**
988 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
989 * @timer: hrtimer used by pm_schedule_suspend().
990 *
991 * Check if the time is right and queue a suspend request.
992 */
993static enum hrtimer_restart pm_suspend_timer_fn(struct hrtimer *timer)
994{
995 struct device *dev = container_of(timer, struct device, power.suspend_timer);
996 unsigned long flags;
997 u64 expires;
998
999 spin_lock_irqsave(&dev->power.lock, flags);
1000
1001 expires = dev->power.timer_expires;
1002 /*
1003 * If 'expires' is after the current time, we've been called
1004 * too early.
1005 */
1006 if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
1007 dev->power.timer_expires = 0;
1008 rpm_suspend(dev, dev->power.timer_autosuspends ?
1009 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
1010 }
1011
1012 spin_unlock_irqrestore(&dev->power.lock, flags);
1013
1014 return HRTIMER_NORESTART;
1015}
1016
1017/**
1018 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
1019 * @dev: Device to suspend.
1020 * @delay: Time to wait before submitting a suspend request, in milliseconds.
1021 */
1022int pm_schedule_suspend(struct device *dev, unsigned int delay)
1023{
1024 unsigned long flags;
1025 u64 expires;
1026 int retval;
1027
1028 spin_lock_irqsave(&dev->power.lock, flags);
1029
1030 if (!delay) {
1031 retval = rpm_suspend(dev, RPM_ASYNC);
1032 goto out;
1033 }
1034
1035 retval = rpm_check_suspend_allowed(dev);
1036 if (retval)
1037 goto out;
1038
1039 /* Other scheduled or pending requests need to be canceled. */
1040 pm_runtime_cancel_pending(dev);
1041
1042 expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC;
1043 dev->power.timer_expires = expires;
1044 dev->power.timer_autosuspends = 0;
1045 hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);
1046
1047 out:
1048 spin_unlock_irqrestore(&dev->power.lock, flags);
1049
1050 return retval;
1051}
1052EXPORT_SYMBOL_GPL(pm_schedule_suspend);
1053
1054static int rpm_drop_usage_count(struct device *dev)
1055{
1056 int ret;
1057
1058 ret = atomic_sub_return(1, &dev->power.usage_count);
1059 if (ret >= 0)
1060 return ret;
1061
1062 /*
1063 * Because rpm_resume() does not check the usage counter, it will resume
1064 * the device even if the usage counter is 0 or negative, so it is
1065 * sufficient to increment the usage counter here to reverse the change
1066 * made above.
1067 */
1068 atomic_inc(&dev->power.usage_count);
1069 dev_warn(dev, "Runtime PM usage count underflow!\n");
1070 return -EINVAL;
1071}
1072
1073/**
1074 * __pm_runtime_idle - Entry point for runtime idle operations.
1075 * @dev: Device to send idle notification for.
1076 * @rpmflags: Flag bits.
1077 *
1078 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1079 * return immediately if it is larger than zero (if it becomes negative, log a
1080 * warning, increment it, and return an error). Then carry out an idle
1081 * notification, either synchronous or asynchronous.
1082 *
1083 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1084 * or if pm_runtime_irq_safe() has been called.
1085 */
1086int __pm_runtime_idle(struct device *dev, int rpmflags)
1087{
1088 unsigned long flags;
1089 int retval;
1090
1091 if (rpmflags & RPM_GET_PUT) {
1092 retval = rpm_drop_usage_count(dev);
1093 if (retval < 0) {
1094 return retval;
1095 } else if (retval > 0) {
1096 trace_rpm_usage(dev, rpmflags);
1097 return 0;
1098 }
1099 }
1100
1101 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1102
1103 spin_lock_irqsave(&dev->power.lock, flags);
1104 retval = rpm_idle(dev, rpmflags);
1105 spin_unlock_irqrestore(&dev->power.lock, flags);
1106
1107 return retval;
1108}
1109EXPORT_SYMBOL_GPL(__pm_runtime_idle);
1110
1111/**
1112 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
1113 * @dev: Device to suspend.
1114 * @rpmflags: Flag bits.
1115 *
1116 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1117 * return immediately if it is larger than zero (if it becomes negative, log a
1118 * warning, increment it, and return an error). Then carry out a suspend,
1119 * either synchronous or asynchronous.
1120 *
1121 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1122 * or if pm_runtime_irq_safe() has been called.
1123 */
1124int __pm_runtime_suspend(struct device *dev, int rpmflags)
1125{
1126 unsigned long flags;
1127 int retval;
1128
1129 if (rpmflags & RPM_GET_PUT) {
1130 retval = rpm_drop_usage_count(dev);
1131 if (retval < 0) {
1132 return retval;
1133 } else if (retval > 0) {
1134 trace_rpm_usage(dev, rpmflags);
1135 return 0;
1136 }
1137 }
1138
1139 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1140
1141 spin_lock_irqsave(&dev->power.lock, flags);
1142 retval = rpm_suspend(dev, rpmflags);
1143 spin_unlock_irqrestore(&dev->power.lock, flags);
1144
1145 return retval;
1146}
1147EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
1148
1149/**
1150 * __pm_runtime_resume - Entry point for runtime resume operations.
1151 * @dev: Device to resume.
1152 * @rpmflags: Flag bits.
1153 *
1154 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
1155 * carry out a resume, either synchronous or asynchronous.
1156 *
1157 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1158 * or if pm_runtime_irq_safe() has been called.
1159 */
1160int __pm_runtime_resume(struct device *dev, int rpmflags)
1161{
1162 unsigned long flags;
1163 int retval;
1164
1165 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
1166 dev->power.runtime_status != RPM_ACTIVE);
1167
1168 if (rpmflags & RPM_GET_PUT)
1169 atomic_inc(&dev->power.usage_count);
1170
1171 spin_lock_irqsave(&dev->power.lock, flags);
1172 retval = rpm_resume(dev, rpmflags);
1173 spin_unlock_irqrestore(&dev->power.lock, flags);
1174
1175 return retval;
1176}
1177EXPORT_SYMBOL_GPL(__pm_runtime_resume);
1178
1179/**
1180 * pm_runtime_get_conditional - Conditionally bump up device usage counter.
1181 * @dev: Device to handle.
1182 * @ign_usage_count: Whether or not to look at the current usage counter value.
1183 *
1184 * Return -EINVAL if runtime PM is disabled for @dev.
1185 *
1186 * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either
1187 * @ign_usage_count is %true or the runtime PM usage counter of @dev is not
1188 * zero, increment the usage counter of @dev and return 1. Otherwise, return 0
1189 * without changing the usage counter.
1190 *
1191 * If @ign_usage_count is %true, this function can be used to prevent suspending
1192 * the device when its runtime PM status is %RPM_ACTIVE.
1193 *
1194 * If @ign_usage_count is %false, this function can be used to prevent
1195 * suspending the device when both its runtime PM status is %RPM_ACTIVE and its
1196 * runtime PM usage counter is not zero.
1197 *
1198 * The caller is responsible for decrementing the runtime PM usage counter of
1199 * @dev after this function has returned a positive value for it.
1200 */
1201static int pm_runtime_get_conditional(struct device *dev, bool ign_usage_count)
1202{
1203 unsigned long flags;
1204 int retval;
1205
1206 spin_lock_irqsave(&dev->power.lock, flags);
1207 if (dev->power.disable_depth > 0) {
1208 retval = -EINVAL;
1209 } else if (dev->power.runtime_status != RPM_ACTIVE) {
1210 retval = 0;
1211 } else if (ign_usage_count) {
1212 retval = 1;
1213 atomic_inc(&dev->power.usage_count);
1214 } else {
1215 retval = atomic_inc_not_zero(&dev->power.usage_count);
1216 }
1217 trace_rpm_usage(dev, 0);
1218 spin_unlock_irqrestore(&dev->power.lock, flags);
1219
1220 return retval;
1221}
1222
1223/**
1224 * pm_runtime_get_if_active - Bump up runtime PM usage counter if the device is
1225 * in active state
1226 * @dev: Target device.
1227 *
1228 * Increment the runtime PM usage counter of @dev if its runtime PM status is
1229 * %RPM_ACTIVE, in which case it returns 1. If the device is in a different
1230 * state, 0 is returned. -EINVAL is returned if runtime PM is disabled for the
1231 * device, in which case also the usage_count will remain unmodified.
1232 */
1233int pm_runtime_get_if_active(struct device *dev)
1234{
1235 return pm_runtime_get_conditional(dev, true);
1236}
1237EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
1238
1239/**
1240 * pm_runtime_get_if_in_use - Conditionally bump up runtime PM usage counter.
1241 * @dev: Target device.
1242 *
1243 * Increment the runtime PM usage counter of @dev if its runtime PM status is
1244 * %RPM_ACTIVE and its runtime PM usage counter is greater than 0, in which case
1245 * it returns 1. If the device is in a different state or its usage_count is 0,
1246 * 0 is returned. -EINVAL is returned if runtime PM is disabled for the device,
1247 * in which case also the usage_count will remain unmodified.
1248 */
1249int pm_runtime_get_if_in_use(struct device *dev)
1250{
1251 return pm_runtime_get_conditional(dev, false);
1252}
1253EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
1254
1255/**
1256 * __pm_runtime_set_status - Set runtime PM status of a device.
1257 * @dev: Device to handle.
1258 * @status: New runtime PM status of the device.
1259 *
1260 * If runtime PM of the device is disabled or its power.runtime_error field is
1261 * different from zero, the status may be changed either to RPM_ACTIVE, or to
1262 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1263 * However, if the device has a parent and the parent is not active, and the
1264 * parent's power.ignore_children flag is unset, the device's status cannot be
1265 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1266 *
1267 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1268 * and the device parent's counter of unsuspended children is modified to
1269 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
1270 * notification request for the parent is submitted.
1271 *
1272 * If @dev has any suppliers (as reflected by device links to them), and @status
1273 * is RPM_ACTIVE, they will be activated upfront and if the activation of one
1274 * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead
1275 * of the @status value) and the suppliers will be deacticated on exit. The
1276 * error returned by the failing supplier activation will be returned in that
1277 * case.
1278 */
1279int __pm_runtime_set_status(struct device *dev, unsigned int status)
1280{
1281 struct device *parent = dev->parent;
1282 bool notify_parent = false;
1283 unsigned long flags;
1284 int error = 0;
1285
1286 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1287 return -EINVAL;
1288
1289 spin_lock_irqsave(&dev->power.lock, flags);
1290
1291 /*
1292 * Prevent PM-runtime from being enabled for the device or return an
1293 * error if it is enabled already and working.
1294 */
1295 if (dev->power.runtime_error || dev->power.disable_depth)
1296 dev->power.disable_depth++;
1297 else
1298 error = -EAGAIN;
1299
1300 spin_unlock_irqrestore(&dev->power.lock, flags);
1301
1302 if (error)
1303 return error;
1304
1305 /*
1306 * If the new status is RPM_ACTIVE, the suppliers can be activated
1307 * upfront regardless of the current status, because next time
1308 * rpm_put_suppliers() runs, the rpm_active refcounts of the links
1309 * involved will be dropped down to one anyway.
1310 */
1311 if (status == RPM_ACTIVE) {
1312 int idx = device_links_read_lock();
1313
1314 error = rpm_get_suppliers(dev);
1315 if (error)
1316 status = RPM_SUSPENDED;
1317
1318 device_links_read_unlock(idx);
1319 }
1320
1321 spin_lock_irqsave(&dev->power.lock, flags);
1322
1323 if (dev->power.runtime_status == status || !parent)
1324 goto out_set;
1325
1326 if (status == RPM_SUSPENDED) {
1327 atomic_add_unless(&parent->power.child_count, -1, 0);
1328 notify_parent = !parent->power.ignore_children;
1329 } else {
1330 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1331
1332 /*
1333 * It is invalid to put an active child under a parent that is
1334 * not active, has runtime PM enabled and the
1335 * 'power.ignore_children' flag unset.
1336 */
1337 if (!parent->power.disable_depth &&
1338 !parent->power.ignore_children &&
1339 parent->power.runtime_status != RPM_ACTIVE) {
1340 dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1341 dev_name(dev),
1342 dev_name(parent));
1343 error = -EBUSY;
1344 } else if (dev->power.runtime_status == RPM_SUSPENDED) {
1345 atomic_inc(&parent->power.child_count);
1346 }
1347
1348 spin_unlock(&parent->power.lock);
1349
1350 if (error) {
1351 status = RPM_SUSPENDED;
1352 goto out;
1353 }
1354 }
1355
1356 out_set:
1357 __update_runtime_status(dev, status);
1358 if (!error)
1359 dev->power.runtime_error = 0;
1360
1361 out:
1362 spin_unlock_irqrestore(&dev->power.lock, flags);
1363
1364 if (notify_parent)
1365 pm_request_idle(parent);
1366
1367 if (status == RPM_SUSPENDED) {
1368 int idx = device_links_read_lock();
1369
1370 rpm_put_suppliers(dev);
1371
1372 device_links_read_unlock(idx);
1373 }
1374
1375 pm_runtime_enable(dev);
1376
1377 return error;
1378}
1379EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1380
1381/**
1382 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1383 * @dev: Device to handle.
1384 *
1385 * Flush all pending requests for the device from pm_wq and wait for all
1386 * runtime PM operations involving the device in progress to complete.
1387 *
1388 * Should be called under dev->power.lock with interrupts disabled.
1389 */
1390static void __pm_runtime_barrier(struct device *dev)
1391{
1392 pm_runtime_deactivate_timer(dev);
1393
1394 if (dev->power.request_pending) {
1395 dev->power.request = RPM_REQ_NONE;
1396 spin_unlock_irq(&dev->power.lock);
1397
1398 cancel_work_sync(&dev->power.work);
1399
1400 spin_lock_irq(&dev->power.lock);
1401 dev->power.request_pending = false;
1402 }
1403
1404 if (dev->power.runtime_status == RPM_SUSPENDING ||
1405 dev->power.runtime_status == RPM_RESUMING ||
1406 dev->power.idle_notification) {
1407 DEFINE_WAIT(wait);
1408
1409 /* Suspend, wake-up or idle notification in progress. */
1410 for (;;) {
1411 prepare_to_wait(&dev->power.wait_queue, &wait,
1412 TASK_UNINTERRUPTIBLE);
1413 if (dev->power.runtime_status != RPM_SUSPENDING
1414 && dev->power.runtime_status != RPM_RESUMING
1415 && !dev->power.idle_notification)
1416 break;
1417 spin_unlock_irq(&dev->power.lock);
1418
1419 schedule();
1420
1421 spin_lock_irq(&dev->power.lock);
1422 }
1423 finish_wait(&dev->power.wait_queue, &wait);
1424 }
1425}
1426
1427/**
1428 * pm_runtime_barrier - Flush pending requests and wait for completions.
1429 * @dev: Device to handle.
1430 *
1431 * Prevent the device from being suspended by incrementing its usage counter and
1432 * if there's a pending resume request for the device, wake the device up.
1433 * Next, make sure that all pending requests for the device have been flushed
1434 * from pm_wq and wait for all runtime PM operations involving the device in
1435 * progress to complete.
1436 *
1437 * Return value:
1438 * 1, if there was a resume request pending and the device had to be woken up,
1439 * 0, otherwise
1440 */
1441int pm_runtime_barrier(struct device *dev)
1442{
1443 int retval = 0;
1444
1445 pm_runtime_get_noresume(dev);
1446 spin_lock_irq(&dev->power.lock);
1447
1448 if (dev->power.request_pending
1449 && dev->power.request == RPM_REQ_RESUME) {
1450 rpm_resume(dev, 0);
1451 retval = 1;
1452 }
1453
1454 __pm_runtime_barrier(dev);
1455
1456 spin_unlock_irq(&dev->power.lock);
1457 pm_runtime_put_noidle(dev);
1458
1459 return retval;
1460}
1461EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1462
1463/**
1464 * __pm_runtime_disable - Disable runtime PM of a device.
1465 * @dev: Device to handle.
1466 * @check_resume: If set, check if there's a resume request for the device.
1467 *
1468 * Increment power.disable_depth for the device and if it was zero previously,
1469 * cancel all pending runtime PM requests for the device and wait for all
1470 * operations in progress to complete. The device can be either active or
1471 * suspended after its runtime PM has been disabled.
1472 *
1473 * If @check_resume is set and there's a resume request pending when
1474 * __pm_runtime_disable() is called and power.disable_depth is zero, the
1475 * function will wake up the device before disabling its runtime PM.
1476 */
1477void __pm_runtime_disable(struct device *dev, bool check_resume)
1478{
1479 spin_lock_irq(&dev->power.lock);
1480
1481 if (dev->power.disable_depth > 0) {
1482 dev->power.disable_depth++;
1483 goto out;
1484 }
1485
1486 /*
1487 * Wake up the device if there's a resume request pending, because that
1488 * means there probably is some I/O to process and disabling runtime PM
1489 * shouldn't prevent the device from processing the I/O.
1490 */
1491 if (check_resume && dev->power.request_pending &&
1492 dev->power.request == RPM_REQ_RESUME) {
1493 /*
1494 * Prevent suspends and idle notifications from being carried
1495 * out after we have woken up the device.
1496 */
1497 pm_runtime_get_noresume(dev);
1498
1499 rpm_resume(dev, 0);
1500
1501 pm_runtime_put_noidle(dev);
1502 }
1503
1504 /* Update time accounting before disabling PM-runtime. */
1505 update_pm_runtime_accounting(dev);
1506
1507 if (!dev->power.disable_depth++) {
1508 __pm_runtime_barrier(dev);
1509 dev->power.last_status = dev->power.runtime_status;
1510 }
1511
1512 out:
1513 spin_unlock_irq(&dev->power.lock);
1514}
1515EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1516
1517/**
1518 * pm_runtime_enable - Enable runtime PM of a device.
1519 * @dev: Device to handle.
1520 */
1521void pm_runtime_enable(struct device *dev)
1522{
1523 unsigned long flags;
1524
1525 spin_lock_irqsave(&dev->power.lock, flags);
1526
1527 if (!dev->power.disable_depth) {
1528 dev_warn(dev, "Unbalanced %s!\n", __func__);
1529 goto out;
1530 }
1531
1532 if (--dev->power.disable_depth > 0)
1533 goto out;
1534
1535 dev->power.last_status = RPM_INVALID;
1536 dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
1537
1538 if (dev->power.runtime_status == RPM_SUSPENDED &&
1539 !dev->power.ignore_children &&
1540 atomic_read(&dev->power.child_count) > 0)
1541 dev_warn(dev, "Enabling runtime PM for inactive device with active children\n");
1542
1543out:
1544 spin_unlock_irqrestore(&dev->power.lock, flags);
1545}
1546EXPORT_SYMBOL_GPL(pm_runtime_enable);
1547
1548static void pm_runtime_disable_action(void *data)
1549{
1550 pm_runtime_dont_use_autosuspend(data);
1551 pm_runtime_disable(data);
1552}
1553
1554/**
1555 * devm_pm_runtime_enable - devres-enabled version of pm_runtime_enable.
1556 *
1557 * NOTE: this will also handle calling pm_runtime_dont_use_autosuspend() for
1558 * you at driver exit time if needed.
1559 *
1560 * @dev: Device to handle.
1561 */
1562int devm_pm_runtime_enable(struct device *dev)
1563{
1564 pm_runtime_enable(dev);
1565
1566 return devm_add_action_or_reset(dev, pm_runtime_disable_action, dev);
1567}
1568EXPORT_SYMBOL_GPL(devm_pm_runtime_enable);
1569
1570/**
1571 * pm_runtime_forbid - Block runtime PM of a device.
1572 * @dev: Device to handle.
1573 *
1574 * Increase the device's usage count and clear its power.runtime_auto flag,
1575 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1576 * for it.
1577 */
1578void pm_runtime_forbid(struct device *dev)
1579{
1580 spin_lock_irq(&dev->power.lock);
1581 if (!dev->power.runtime_auto)
1582 goto out;
1583
1584 dev->power.runtime_auto = false;
1585 atomic_inc(&dev->power.usage_count);
1586 rpm_resume(dev, 0);
1587
1588 out:
1589 spin_unlock_irq(&dev->power.lock);
1590}
1591EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1592
1593/**
1594 * pm_runtime_allow - Unblock runtime PM of a device.
1595 * @dev: Device to handle.
1596 *
1597 * Decrease the device's usage count and set its power.runtime_auto flag.
1598 */
1599void pm_runtime_allow(struct device *dev)
1600{
1601 int ret;
1602
1603 spin_lock_irq(&dev->power.lock);
1604 if (dev->power.runtime_auto)
1605 goto out;
1606
1607 dev->power.runtime_auto = true;
1608 ret = rpm_drop_usage_count(dev);
1609 if (ret == 0)
1610 rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1611 else if (ret > 0)
1612 trace_rpm_usage(dev, RPM_AUTO | RPM_ASYNC);
1613
1614 out:
1615 spin_unlock_irq(&dev->power.lock);
1616}
1617EXPORT_SYMBOL_GPL(pm_runtime_allow);
1618
1619/**
1620 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1621 * @dev: Device to handle.
1622 *
1623 * Set the power.no_callbacks flag, which tells the PM core that this
1624 * device is power-managed through its parent and has no runtime PM
1625 * callbacks of its own. The runtime sysfs attributes will be removed.
1626 */
1627void pm_runtime_no_callbacks(struct device *dev)
1628{
1629 spin_lock_irq(&dev->power.lock);
1630 dev->power.no_callbacks = 1;
1631 spin_unlock_irq(&dev->power.lock);
1632 if (device_is_registered(dev))
1633 rpm_sysfs_remove(dev);
1634}
1635EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1636
1637/**
1638 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1639 * @dev: Device to handle
1640 *
1641 * Set the power.irq_safe flag, which tells the PM core that the
1642 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1643 * always be invoked with the spinlock held and interrupts disabled. It also
1644 * causes the parent's usage counter to be permanently incremented, preventing
1645 * the parent from runtime suspending -- otherwise an irq-safe child might have
1646 * to wait for a non-irq-safe parent.
1647 */
1648void pm_runtime_irq_safe(struct device *dev)
1649{
1650 if (dev->parent)
1651 pm_runtime_get_sync(dev->parent);
1652
1653 spin_lock_irq(&dev->power.lock);
1654 dev->power.irq_safe = 1;
1655 spin_unlock_irq(&dev->power.lock);
1656}
1657EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1658
1659/**
1660 * update_autosuspend - Handle a change to a device's autosuspend settings.
1661 * @dev: Device to handle.
1662 * @old_delay: The former autosuspend_delay value.
1663 * @old_use: The former use_autosuspend value.
1664 *
1665 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1666 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1667 *
1668 * This function must be called under dev->power.lock with interrupts disabled.
1669 */
1670static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1671{
1672 int delay = dev->power.autosuspend_delay;
1673
1674 /* Should runtime suspend be prevented now? */
1675 if (dev->power.use_autosuspend && delay < 0) {
1676
1677 /* If it used to be allowed then prevent it. */
1678 if (!old_use || old_delay >= 0) {
1679 atomic_inc(&dev->power.usage_count);
1680 rpm_resume(dev, 0);
1681 } else {
1682 trace_rpm_usage(dev, 0);
1683 }
1684 }
1685
1686 /* Runtime suspend should be allowed now. */
1687 else {
1688
1689 /* If it used to be prevented then allow it. */
1690 if (old_use && old_delay < 0)
1691 atomic_dec(&dev->power.usage_count);
1692
1693 /* Maybe we can autosuspend now. */
1694 rpm_idle(dev, RPM_AUTO);
1695 }
1696}
1697
1698/**
1699 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1700 * @dev: Device to handle.
1701 * @delay: Value of the new delay in milliseconds.
1702 *
1703 * Set the device's power.autosuspend_delay value. If it changes to negative
1704 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1705 * changes the other way, allow runtime suspends.
1706 */
1707void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1708{
1709 int old_delay, old_use;
1710
1711 spin_lock_irq(&dev->power.lock);
1712 old_delay = dev->power.autosuspend_delay;
1713 old_use = dev->power.use_autosuspend;
1714 dev->power.autosuspend_delay = delay;
1715 update_autosuspend(dev, old_delay, old_use);
1716 spin_unlock_irq(&dev->power.lock);
1717}
1718EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1719
1720/**
1721 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1722 * @dev: Device to handle.
1723 * @use: New value for use_autosuspend.
1724 *
1725 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1726 * suspends as needed.
1727 */
1728void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1729{
1730 int old_delay, old_use;
1731
1732 spin_lock_irq(&dev->power.lock);
1733 old_delay = dev->power.autosuspend_delay;
1734 old_use = dev->power.use_autosuspend;
1735 dev->power.use_autosuspend = use;
1736 update_autosuspend(dev, old_delay, old_use);
1737 spin_unlock_irq(&dev->power.lock);
1738}
1739EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1740
1741/**
1742 * pm_runtime_init - Initialize runtime PM fields in given device object.
1743 * @dev: Device object to initialize.
1744 */
1745void pm_runtime_init(struct device *dev)
1746{
1747 dev->power.runtime_status = RPM_SUSPENDED;
1748 dev->power.last_status = RPM_INVALID;
1749 dev->power.idle_notification = false;
1750
1751 dev->power.disable_depth = 1;
1752 atomic_set(&dev->power.usage_count, 0);
1753
1754 dev->power.runtime_error = 0;
1755
1756 atomic_set(&dev->power.child_count, 0);
1757 pm_suspend_ignore_children(dev, false);
1758 dev->power.runtime_auto = true;
1759
1760 dev->power.request_pending = false;
1761 dev->power.request = RPM_REQ_NONE;
1762 dev->power.deferred_resume = false;
1763 dev->power.needs_force_resume = 0;
1764 INIT_WORK(&dev->power.work, pm_runtime_work);
1765
1766 dev->power.timer_expires = 0;
1767 hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1768 dev->power.suspend_timer.function = pm_suspend_timer_fn;
1769
1770 init_waitqueue_head(&dev->power.wait_queue);
1771}
1772
1773/**
1774 * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1775 * @dev: Device object to re-initialize.
1776 */
1777void pm_runtime_reinit(struct device *dev)
1778{
1779 if (!pm_runtime_enabled(dev)) {
1780 if (dev->power.runtime_status == RPM_ACTIVE)
1781 pm_runtime_set_suspended(dev);
1782 if (dev->power.irq_safe) {
1783 spin_lock_irq(&dev->power.lock);
1784 dev->power.irq_safe = 0;
1785 spin_unlock_irq(&dev->power.lock);
1786 if (dev->parent)
1787 pm_runtime_put(dev->parent);
1788 }
1789 }
1790}
1791
1792/**
1793 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1794 * @dev: Device object being removed from device hierarchy.
1795 */
1796void pm_runtime_remove(struct device *dev)
1797{
1798 __pm_runtime_disable(dev, false);
1799 pm_runtime_reinit(dev);
1800}
1801
1802/**
1803 * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
1804 * @dev: Consumer device.
1805 */
1806void pm_runtime_get_suppliers(struct device *dev)
1807{
1808 struct device_link *link;
1809 int idx;
1810
1811 idx = device_links_read_lock();
1812
1813 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1814 device_links_read_lock_held())
1815 if (link->flags & DL_FLAG_PM_RUNTIME) {
1816 link->supplier_preactivated = true;
1817 pm_runtime_get_sync(link->supplier);
1818 }
1819
1820 device_links_read_unlock(idx);
1821}
1822
1823/**
1824 * pm_runtime_put_suppliers - Drop references to supplier devices.
1825 * @dev: Consumer device.
1826 */
1827void pm_runtime_put_suppliers(struct device *dev)
1828{
1829 struct device_link *link;
1830 int idx;
1831
1832 idx = device_links_read_lock();
1833
1834 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1835 device_links_read_lock_held())
1836 if (link->supplier_preactivated) {
1837 link->supplier_preactivated = false;
1838 pm_runtime_put(link->supplier);
1839 }
1840
1841 device_links_read_unlock(idx);
1842}
1843
1844void pm_runtime_new_link(struct device *dev)
1845{
1846 spin_lock_irq(&dev->power.lock);
1847 dev->power.links_count++;
1848 spin_unlock_irq(&dev->power.lock);
1849}
1850
1851static void pm_runtime_drop_link_count(struct device *dev)
1852{
1853 spin_lock_irq(&dev->power.lock);
1854 WARN_ON(dev->power.links_count == 0);
1855 dev->power.links_count--;
1856 spin_unlock_irq(&dev->power.lock);
1857}
1858
1859/**
1860 * pm_runtime_drop_link - Prepare for device link removal.
1861 * @link: Device link going away.
1862 *
1863 * Drop the link count of the consumer end of @link and decrement the supplier
1864 * device's runtime PM usage counter as many times as needed to drop all of the
1865 * PM runtime reference to it from the consumer.
1866 */
1867void pm_runtime_drop_link(struct device_link *link)
1868{
1869 if (!(link->flags & DL_FLAG_PM_RUNTIME))
1870 return;
1871
1872 pm_runtime_drop_link_count(link->consumer);
1873 pm_runtime_release_supplier(link);
1874 pm_request_idle(link->supplier);
1875}
1876
1877static bool pm_runtime_need_not_resume(struct device *dev)
1878{
1879 return atomic_read(&dev->power.usage_count) <= 1 &&
1880 (atomic_read(&dev->power.child_count) == 0 ||
1881 dev->power.ignore_children);
1882}
1883
1884/**
1885 * pm_runtime_force_suspend - Force a device into suspend state if needed.
1886 * @dev: Device to suspend.
1887 *
1888 * Disable runtime PM so we safely can check the device's runtime PM status and
1889 * if it is active, invoke its ->runtime_suspend callback to suspend it and
1890 * change its runtime PM status field to RPM_SUSPENDED. Also, if the device's
1891 * usage and children counters don't indicate that the device was in use before
1892 * the system-wide transition under way, decrement its parent's children counter
1893 * (if there is a parent). Keep runtime PM disabled to preserve the state
1894 * unless we encounter errors.
1895 *
1896 * Typically this function may be invoked from a system suspend callback to make
1897 * sure the device is put into low power state and it should only be used during
1898 * system-wide PM transitions to sleep states. It assumes that the analogous
1899 * pm_runtime_force_resume() will be used to resume the device.
1900 *
1901 * Do not use with DPM_FLAG_SMART_SUSPEND as this can lead to an inconsistent
1902 * state where this function has called the ->runtime_suspend callback but the
1903 * PM core marks the driver as runtime active.
1904 */
1905int pm_runtime_force_suspend(struct device *dev)
1906{
1907 int (*callback)(struct device *);
1908 int ret;
1909
1910 pm_runtime_disable(dev);
1911 if (pm_runtime_status_suspended(dev))
1912 return 0;
1913
1914 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1915
1916 dev_pm_enable_wake_irq_check(dev, true);
1917 ret = callback ? callback(dev) : 0;
1918 if (ret)
1919 goto err;
1920
1921 dev_pm_enable_wake_irq_complete(dev);
1922
1923 /*
1924 * If the device can stay in suspend after the system-wide transition
1925 * to the working state that will follow, drop the children counter of
1926 * its parent, but set its status to RPM_SUSPENDED anyway in case this
1927 * function will be called again for it in the meantime.
1928 */
1929 if (pm_runtime_need_not_resume(dev)) {
1930 pm_runtime_set_suspended(dev);
1931 } else {
1932 __update_runtime_status(dev, RPM_SUSPENDED);
1933 dev->power.needs_force_resume = 1;
1934 }
1935
1936 return 0;
1937
1938err:
1939 dev_pm_disable_wake_irq_check(dev, true);
1940 pm_runtime_enable(dev);
1941 return ret;
1942}
1943EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1944
1945/**
1946 * pm_runtime_force_resume - Force a device into resume state if needed.
1947 * @dev: Device to resume.
1948 *
1949 * Prior invoking this function we expect the user to have brought the device
1950 * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1951 * those actions and bring the device into full power, if it is expected to be
1952 * used on system resume. In the other case, we defer the resume to be managed
1953 * via runtime PM.
1954 *
1955 * Typically this function may be invoked from a system resume callback.
1956 */
1957int pm_runtime_force_resume(struct device *dev)
1958{
1959 int (*callback)(struct device *);
1960 int ret = 0;
1961
1962 if (!pm_runtime_status_suspended(dev) || !dev->power.needs_force_resume)
1963 goto out;
1964
1965 /*
1966 * The value of the parent's children counter is correct already, so
1967 * just update the status of the device.
1968 */
1969 __update_runtime_status(dev, RPM_ACTIVE);
1970
1971 callback = RPM_GET_CALLBACK(dev, runtime_resume);
1972
1973 dev_pm_disable_wake_irq_check(dev, false);
1974 ret = callback ? callback(dev) : 0;
1975 if (ret) {
1976 pm_runtime_set_suspended(dev);
1977 dev_pm_enable_wake_irq_check(dev, false);
1978 goto out;
1979 }
1980
1981 pm_runtime_mark_last_busy(dev);
1982out:
1983 dev->power.needs_force_resume = 0;
1984 pm_runtime_enable(dev);
1985 return ret;
1986}
1987EXPORT_SYMBOL_GPL(pm_runtime_force_resume);