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

source code of linux/drivers/base/power/runtime.c