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