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
19 typedef int (*pm_callback_t)(struct device *);
20
__rpm_get_callback(struct device * dev,size_t cb_offset)21 static 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
51 static int rpm_resume(struct device *dev, int rpmflags);
52 static 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 */
update_pm_runtime_accounting(struct device * dev)65 static 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
__update_runtime_status(struct device * dev,enum rpm_status status)93 static 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
rpm_get_accounted_time(struct device * dev,bool suspended)99 static 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
pm_runtime_active_time(struct device * dev)114 u64 pm_runtime_active_time(struct device *dev)
115 {
116 return rpm_get_accounted_time(dev, false);
117 }
118
pm_runtime_suspended_time(struct device * dev)119 u64 pm_runtime_suspended_time(struct device *dev)
120 {
121 return rpm_get_accounted_time(dev, true);
122 }
123 EXPORT_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 */
pm_runtime_deactivate_timer(struct device * dev)129 static 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 */
pm_runtime_cancel_pending(struct device * dev)141 static 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 */
pm_runtime_autosuspend_expiration(struct device * dev)163 u64 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 }
182 EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration);
183
dev_memalloc_noio(struct device * dev,void * data)184 static 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 */
pm_runtime_set_memalloc_noio(struct device * dev,bool enable)217 void 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 }
252 EXPORT_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 */
rpm_check_suspend_allowed(struct device * dev)258 static 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
rpm_get_suppliers(struct device * dev)286 static 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 continue;
296
297 retval = pm_runtime_get_sync(link->supplier);
298 /* Ignore suppliers with disabled runtime PM. */
299 if (retval < 0 && retval != -EACCES) {
300 pm_runtime_put_noidle(link->supplier);
301 return retval;
302 }
303 refcount_inc(&link->rpm_active);
304 }
305 return 0;
306 }
307
308 /**
309 * pm_runtime_release_supplier - Drop references to device link's supplier.
310 * @link: Target device link.
311 *
312 * Drop all runtime PM references associated with @link to its supplier device.
313 */
pm_runtime_release_supplier(struct device_link * link)314 void pm_runtime_release_supplier(struct device_link *link)
315 {
316 struct device *supplier = link->supplier;
317
318 /*
319 * The additional power.usage_count check is a safety net in case
320 * the rpm_active refcount becomes saturated, in which case
321 * refcount_dec_not_one() would return true forever, but it is not
322 * strictly necessary.
323 */
324 while (refcount_dec_not_one(&link->rpm_active) &&
325 atomic_read(&supplier->power.usage_count) > 0)
326 pm_runtime_put_noidle(supplier);
327 }
328
__rpm_put_suppliers(struct device * dev,bool try_to_suspend)329 static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend)
330 {
331 struct device_link *link;
332
333 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
334 device_links_read_lock_held()) {
335 pm_runtime_release_supplier(link);
336 if (try_to_suspend)
337 pm_request_idle(link->supplier);
338 }
339 }
340
rpm_put_suppliers(struct device * dev)341 static void rpm_put_suppliers(struct device *dev)
342 {
343 __rpm_put_suppliers(dev, true);
344 }
345
rpm_suspend_suppliers(struct device * dev)346 static void rpm_suspend_suppliers(struct device *dev)
347 {
348 struct device_link *link;
349 int idx = device_links_read_lock();
350
351 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
352 device_links_read_lock_held())
353 pm_request_idle(link->supplier);
354
355 device_links_read_unlock(idx);
356 }
357
358 /**
359 * __rpm_callback - Run a given runtime PM callback for a given device.
360 * @cb: Runtime PM callback to run.
361 * @dev: Device to run the callback for.
362 */
__rpm_callback(int (* cb)(struct device *),struct device * dev)363 static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
364 __releases(&dev->power.lock) __acquires(&dev->power.lock)
365 {
366 int retval, idx;
367 bool use_links = dev->power.links_count > 0;
368
369 if (dev->power.irq_safe) {
370 spin_unlock(&dev->power.lock);
371 } else {
372 spin_unlock_irq(&dev->power.lock);
373
374 /*
375 * Resume suppliers if necessary.
376 *
377 * The device's runtime PM status cannot change until this
378 * routine returns, so it is safe to read the status outside of
379 * the lock.
380 */
381 if (use_links && dev->power.runtime_status == RPM_RESUMING) {
382 idx = device_links_read_lock();
383
384 retval = rpm_get_suppliers(dev);
385 if (retval) {
386 rpm_put_suppliers(dev);
387 goto fail;
388 }
389
390 device_links_read_unlock(idx);
391 }
392 }
393
394 retval = cb(dev);
395
396 if (dev->power.irq_safe) {
397 spin_lock(&dev->power.lock);
398 } else {
399 /*
400 * If the device is suspending and the callback has returned
401 * success, drop the usage counters of the suppliers that have
402 * been reference counted on its resume.
403 *
404 * Do that if resume fails too.
405 */
406 if (use_links
407 && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
408 || (dev->power.runtime_status == RPM_RESUMING && retval))) {
409 idx = device_links_read_lock();
410
411 __rpm_put_suppliers(dev, false);
412
413 fail:
414 device_links_read_unlock(idx);
415 }
416
417 spin_lock_irq(&dev->power.lock);
418 }
419
420 return retval;
421 }
422
423 /**
424 * rpm_idle - Notify device bus type if the device can be suspended.
425 * @dev: Device to notify the bus type about.
426 * @rpmflags: Flag bits.
427 *
428 * Check if the device's runtime PM status allows it to be suspended. If
429 * another idle notification has been started earlier, return immediately. If
430 * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise
431 * run the ->runtime_idle() callback directly. If the ->runtime_idle callback
432 * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag.
433 *
434 * This function must be called under dev->power.lock with interrupts disabled.
435 */
rpm_idle(struct device * dev,int rpmflags)436 static int rpm_idle(struct device *dev, int rpmflags)
437 {
438 int (*callback)(struct device *);
439 int retval;
440
441 trace_rpm_idle_rcuidle(dev, rpmflags);
442 retval = rpm_check_suspend_allowed(dev);
443 if (retval < 0)
444 ; /* Conditions are wrong. */
445
446 /* Idle notifications are allowed only in the RPM_ACTIVE state. */
447 else if (dev->power.runtime_status != RPM_ACTIVE)
448 retval = -EAGAIN;
449
450 /*
451 * Any pending request other than an idle notification takes
452 * precedence over us, except that the timer may be running.
453 */
454 else if (dev->power.request_pending &&
455 dev->power.request > RPM_REQ_IDLE)
456 retval = -EAGAIN;
457
458 /* Act as though RPM_NOWAIT is always set. */
459 else if (dev->power.idle_notification)
460 retval = -EINPROGRESS;
461 if (retval)
462 goto out;
463
464 /* Pending requests need to be canceled. */
465 dev->power.request = RPM_REQ_NONE;
466
467 callback = RPM_GET_CALLBACK(dev, runtime_idle);
468
469 /* If no callback assume success. */
470 if (!callback || dev->power.no_callbacks)
471 goto out;
472
473 /* Carry out an asynchronous or a synchronous idle notification. */
474 if (rpmflags & RPM_ASYNC) {
475 dev->power.request = RPM_REQ_IDLE;
476 if (!dev->power.request_pending) {
477 dev->power.request_pending = true;
478 queue_work(pm_wq, &dev->power.work);
479 }
480 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0);
481 return 0;
482 }
483
484 dev->power.idle_notification = true;
485
486 if (dev->power.irq_safe)
487 spin_unlock(&dev->power.lock);
488 else
489 spin_unlock_irq(&dev->power.lock);
490
491 retval = callback(dev);
492
493 if (dev->power.irq_safe)
494 spin_lock(&dev->power.lock);
495 else
496 spin_lock_irq(&dev->power.lock);
497
498 dev->power.idle_notification = false;
499 wake_up_all(&dev->power.wait_queue);
500
501 out:
502 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
503 return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO);
504 }
505
506 /**
507 * rpm_callback - Run a given runtime PM callback for a given device.
508 * @cb: Runtime PM callback to run.
509 * @dev: Device to run the callback for.
510 */
rpm_callback(int (* cb)(struct device *),struct device * dev)511 static int rpm_callback(int (*cb)(struct device *), struct device *dev)
512 {
513 int retval;
514
515 if (!cb)
516 return -ENOSYS;
517
518 if (dev->power.memalloc_noio) {
519 unsigned int noio_flag;
520
521 /*
522 * Deadlock might be caused if memory allocation with
523 * GFP_KERNEL happens inside runtime_suspend and
524 * runtime_resume callbacks of one block device's
525 * ancestor or the block device itself. Network
526 * device might be thought as part of iSCSI block
527 * device, so network device and its ancestor should
528 * be marked as memalloc_noio too.
529 */
530 noio_flag = memalloc_noio_save();
531 retval = __rpm_callback(cb, dev);
532 memalloc_noio_restore(noio_flag);
533 } else {
534 retval = __rpm_callback(cb, dev);
535 }
536
537 dev->power.runtime_error = retval;
538 return retval != -EACCES ? retval : -EIO;
539 }
540
541 /**
542 * rpm_suspend - Carry out runtime suspend of given device.
543 * @dev: Device to suspend.
544 * @rpmflags: Flag bits.
545 *
546 * Check if the device's runtime PM status allows it to be suspended.
547 * Cancel a pending idle notification, autosuspend or suspend. If
548 * another suspend has been started earlier, either return immediately
549 * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC
550 * flags. If the RPM_ASYNC flag is set then queue a suspend request;
551 * otherwise run the ->runtime_suspend() callback directly. When
552 * ->runtime_suspend succeeded, if a deferred resume was requested while
553 * the callback was running then carry it out, otherwise send an idle
554 * notification for its parent (if the suspend succeeded and both
555 * ignore_children of parent->power and irq_safe of dev->power are not set).
556 * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO
557 * flag is set and the next autosuspend-delay expiration time is in the
558 * future, schedule another autosuspend attempt.
559 *
560 * This function must be called under dev->power.lock with interrupts disabled.
561 */
rpm_suspend(struct device * dev,int rpmflags)562 static int rpm_suspend(struct device *dev, int rpmflags)
563 __releases(&dev->power.lock) __acquires(&dev->power.lock)
564 {
565 int (*callback)(struct device *);
566 struct device *parent = NULL;
567 int retval;
568
569 trace_rpm_suspend_rcuidle(dev, rpmflags);
570
571 repeat:
572 retval = rpm_check_suspend_allowed(dev);
573 if (retval < 0)
574 goto out; /* Conditions are wrong. */
575
576 /* Synchronous suspends are not allowed in the RPM_RESUMING state. */
577 if (dev->power.runtime_status == RPM_RESUMING && !(rpmflags & RPM_ASYNC))
578 retval = -EAGAIN;
579 if (retval)
580 goto out;
581
582 /* If the autosuspend_delay time hasn't expired yet, reschedule. */
583 if ((rpmflags & RPM_AUTO)
584 && dev->power.runtime_status != RPM_SUSPENDING) {
585 u64 expires = pm_runtime_autosuspend_expiration(dev);
586
587 if (expires != 0) {
588 /* Pending requests need to be canceled. */
589 dev->power.request = RPM_REQ_NONE;
590
591 /*
592 * Optimization: If the timer is already running and is
593 * set to expire at or before the autosuspend delay,
594 * avoid the overhead of resetting it. Just let it
595 * expire; pm_suspend_timer_fn() will take care of the
596 * rest.
597 */
598 if (!(dev->power.timer_expires &&
599 dev->power.timer_expires <= expires)) {
600 /*
601 * We add a slack of 25% to gather wakeups
602 * without sacrificing the granularity.
603 */
604 u64 slack = (u64)READ_ONCE(dev->power.autosuspend_delay) *
605 (NSEC_PER_MSEC >> 2);
606
607 dev->power.timer_expires = expires;
608 hrtimer_start_range_ns(&dev->power.suspend_timer,
609 ns_to_ktime(expires),
610 slack,
611 HRTIMER_MODE_ABS);
612 }
613 dev->power.timer_autosuspends = 1;
614 goto out;
615 }
616 }
617
618 /* Other scheduled or pending requests need to be canceled. */
619 pm_runtime_cancel_pending(dev);
620
621 if (dev->power.runtime_status == RPM_SUSPENDING) {
622 DEFINE_WAIT(wait);
623
624 if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
625 retval = -EINPROGRESS;
626 goto out;
627 }
628
629 if (dev->power.irq_safe) {
630 spin_unlock(&dev->power.lock);
631
632 cpu_relax();
633
634 spin_lock(&dev->power.lock);
635 goto repeat;
636 }
637
638 /* Wait for the other suspend running in parallel with us. */
639 for (;;) {
640 prepare_to_wait(&dev->power.wait_queue, &wait,
641 TASK_UNINTERRUPTIBLE);
642 if (dev->power.runtime_status != RPM_SUSPENDING)
643 break;
644
645 spin_unlock_irq(&dev->power.lock);
646
647 schedule();
648
649 spin_lock_irq(&dev->power.lock);
650 }
651 finish_wait(&dev->power.wait_queue, &wait);
652 goto repeat;
653 }
654
655 if (dev->power.no_callbacks)
656 goto no_callback; /* Assume success. */
657
658 /* Carry out an asynchronous or a synchronous suspend. */
659 if (rpmflags & RPM_ASYNC) {
660 dev->power.request = (rpmflags & RPM_AUTO) ?
661 RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND;
662 if (!dev->power.request_pending) {
663 dev->power.request_pending = true;
664 queue_work(pm_wq, &dev->power.work);
665 }
666 goto out;
667 }
668
669 __update_runtime_status(dev, RPM_SUSPENDING);
670
671 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
672
673 dev_pm_enable_wake_irq_check(dev, true);
674 retval = rpm_callback(callback, dev);
675 if (retval)
676 goto fail;
677
678 no_callback:
679 __update_runtime_status(dev, RPM_SUSPENDED);
680 pm_runtime_deactivate_timer(dev);
681
682 if (dev->parent) {
683 parent = dev->parent;
684 atomic_add_unless(&parent->power.child_count, -1, 0);
685 }
686 wake_up_all(&dev->power.wait_queue);
687
688 if (dev->power.deferred_resume) {
689 dev->power.deferred_resume = false;
690 rpm_resume(dev, 0);
691 retval = -EAGAIN;
692 goto out;
693 }
694
695 if (dev->power.irq_safe)
696 goto out;
697
698 /* Maybe the parent is now able to suspend. */
699 if (parent && !parent->power.ignore_children) {
700 spin_unlock(&dev->power.lock);
701
702 spin_lock(&parent->power.lock);
703 rpm_idle(parent, RPM_ASYNC);
704 spin_unlock(&parent->power.lock);
705
706 spin_lock(&dev->power.lock);
707 }
708 /* Maybe the suppliers are now able to suspend. */
709 if (dev->power.links_count > 0) {
710 spin_unlock_irq(&dev->power.lock);
711
712 rpm_suspend_suppliers(dev);
713
714 spin_lock_irq(&dev->power.lock);
715 }
716
717 out:
718 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
719
720 return retval;
721
722 fail:
723 dev_pm_disable_wake_irq_check(dev);
724 __update_runtime_status(dev, RPM_ACTIVE);
725 dev->power.deferred_resume = false;
726 wake_up_all(&dev->power.wait_queue);
727
728 if (retval == -EAGAIN || retval == -EBUSY) {
729 dev->power.runtime_error = 0;
730
731 /*
732 * If the callback routine failed an autosuspend, and
733 * if the last_busy time has been updated so that there
734 * is a new autosuspend expiration time, automatically
735 * reschedule another autosuspend.
736 */
737 if ((rpmflags & RPM_AUTO) &&
738 pm_runtime_autosuspend_expiration(dev) != 0)
739 goto repeat;
740 } else {
741 pm_runtime_cancel_pending(dev);
742 }
743 goto out;
744 }
745
746 /**
747 * rpm_resume - Carry out runtime resume of given device.
748 * @dev: Device to resume.
749 * @rpmflags: Flag bits.
750 *
751 * Check if the device's runtime PM status allows it to be resumed. Cancel
752 * any scheduled or pending requests. If another resume has been started
753 * earlier, either return immediately or wait for it to finish, depending on the
754 * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in
755 * parallel with this function, either tell the other process to resume after
756 * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC
757 * flag is set then queue a resume request; otherwise run the
758 * ->runtime_resume() callback directly. Queue an idle notification for the
759 * device if the resume succeeded.
760 *
761 * This function must be called under dev->power.lock with interrupts disabled.
762 */
rpm_resume(struct device * dev,int rpmflags)763 static int rpm_resume(struct device *dev, int rpmflags)
764 __releases(&dev->power.lock) __acquires(&dev->power.lock)
765 {
766 int (*callback)(struct device *);
767 struct device *parent = NULL;
768 int retval = 0;
769
770 trace_rpm_resume_rcuidle(dev, rpmflags);
771
772 repeat:
773 if (dev->power.runtime_error)
774 retval = -EINVAL;
775 else if (dev->power.disable_depth == 1 && dev->power.is_suspended
776 && dev->power.runtime_status == RPM_ACTIVE)
777 retval = 1;
778 else if (dev->power.disable_depth > 0)
779 retval = -EACCES;
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 else
806 retval = -EINPROGRESS;
807 goto out;
808 }
809
810 if (dev->power.irq_safe) {
811 spin_unlock(&dev->power.lock);
812
813 cpu_relax();
814
815 spin_lock(&dev->power.lock);
816 goto repeat;
817 }
818
819 /* Wait for the operation carried out in parallel with us. */
820 for (;;) {
821 prepare_to_wait(&dev->power.wait_queue, &wait,
822 TASK_UNINTERRUPTIBLE);
823 if (dev->power.runtime_status != RPM_RESUMING
824 && dev->power.runtime_status != RPM_SUSPENDING)
825 break;
826
827 spin_unlock_irq(&dev->power.lock);
828
829 schedule();
830
831 spin_lock_irq(&dev->power.lock);
832 }
833 finish_wait(&dev->power.wait_queue, &wait);
834 goto repeat;
835 }
836
837 /*
838 * See if we can skip waking up the parent. This is safe only if
839 * power.no_callbacks is set, because otherwise we don't know whether
840 * the resume will actually succeed.
841 */
842 if (dev->power.no_callbacks && !parent && dev->parent) {
843 spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING);
844 if (dev->parent->power.disable_depth > 0
845 || dev->parent->power.ignore_children
846 || dev->parent->power.runtime_status == RPM_ACTIVE) {
847 atomic_inc(&dev->parent->power.child_count);
848 spin_unlock(&dev->parent->power.lock);
849 retval = 1;
850 goto no_callback; /* Assume success. */
851 }
852 spin_unlock(&dev->parent->power.lock);
853 }
854
855 /* Carry out an asynchronous or a synchronous resume. */
856 if (rpmflags & RPM_ASYNC) {
857 dev->power.request = RPM_REQ_RESUME;
858 if (!dev->power.request_pending) {
859 dev->power.request_pending = true;
860 queue_work(pm_wq, &dev->power.work);
861 }
862 retval = 0;
863 goto out;
864 }
865
866 if (!parent && dev->parent) {
867 /*
868 * Increment the parent's usage counter and resume it if
869 * necessary. Not needed if dev is irq-safe; then the
870 * parent is permanently resumed.
871 */
872 parent = dev->parent;
873 if (dev->power.irq_safe)
874 goto skip_parent;
875 spin_unlock(&dev->power.lock);
876
877 pm_runtime_get_noresume(parent);
878
879 spin_lock(&parent->power.lock);
880 /*
881 * Resume the parent if it has runtime PM enabled and not been
882 * set to ignore its children.
883 */
884 if (!parent->power.disable_depth
885 && !parent->power.ignore_children) {
886 rpm_resume(parent, 0);
887 if (parent->power.runtime_status != RPM_ACTIVE)
888 retval = -EBUSY;
889 }
890 spin_unlock(&parent->power.lock);
891
892 spin_lock(&dev->power.lock);
893 if (retval)
894 goto out;
895 goto repeat;
896 }
897 skip_parent:
898
899 if (dev->power.no_callbacks)
900 goto no_callback; /* Assume success. */
901
902 __update_runtime_status(dev, RPM_RESUMING);
903
904 callback = RPM_GET_CALLBACK(dev, runtime_resume);
905
906 dev_pm_disable_wake_irq_check(dev);
907 retval = rpm_callback(callback, dev);
908 if (retval) {
909 __update_runtime_status(dev, RPM_SUSPENDED);
910 pm_runtime_cancel_pending(dev);
911 dev_pm_enable_wake_irq_check(dev, false);
912 } else {
913 no_callback:
914 __update_runtime_status(dev, RPM_ACTIVE);
915 pm_runtime_mark_last_busy(dev);
916 if (parent)
917 atomic_inc(&parent->power.child_count);
918 }
919 wake_up_all(&dev->power.wait_queue);
920
921 if (retval >= 0)
922 rpm_idle(dev, RPM_ASYNC);
923
924 out:
925 if (parent && !dev->power.irq_safe) {
926 spin_unlock_irq(&dev->power.lock);
927
928 pm_runtime_put(parent);
929
930 spin_lock_irq(&dev->power.lock);
931 }
932
933 trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);
934
935 return retval;
936 }
937
938 /**
939 * pm_runtime_work - Universal runtime PM work function.
940 * @work: Work structure used for scheduling the execution of this function.
941 *
942 * Use @work to get the device object the work is to be done for, determine what
943 * is to be done and execute the appropriate runtime PM function.
944 */
pm_runtime_work(struct work_struct * work)945 static void pm_runtime_work(struct work_struct *work)
946 {
947 struct device *dev = container_of(work, struct device, power.work);
948 enum rpm_request req;
949
950 spin_lock_irq(&dev->power.lock);
951
952 if (!dev->power.request_pending)
953 goto out;
954
955 req = dev->power.request;
956 dev->power.request = RPM_REQ_NONE;
957 dev->power.request_pending = false;
958
959 switch (req) {
960 case RPM_REQ_NONE:
961 break;
962 case RPM_REQ_IDLE:
963 rpm_idle(dev, RPM_NOWAIT);
964 break;
965 case RPM_REQ_SUSPEND:
966 rpm_suspend(dev, RPM_NOWAIT);
967 break;
968 case RPM_REQ_AUTOSUSPEND:
969 rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO);
970 break;
971 case RPM_REQ_RESUME:
972 rpm_resume(dev, RPM_NOWAIT);
973 break;
974 }
975
976 out:
977 spin_unlock_irq(&dev->power.lock);
978 }
979
980 /**
981 * pm_suspend_timer_fn - Timer function for pm_schedule_suspend().
982 * @data: Device pointer passed by pm_schedule_suspend().
983 *
984 * Check if the time is right and queue a suspend request.
985 */
pm_suspend_timer_fn(struct hrtimer * timer)986 static enum hrtimer_restart pm_suspend_timer_fn(struct hrtimer *timer)
987 {
988 struct device *dev = container_of(timer, struct device, power.suspend_timer);
989 unsigned long flags;
990 u64 expires;
991
992 spin_lock_irqsave(&dev->power.lock, flags);
993
994 expires = dev->power.timer_expires;
995 /*
996 * If 'expires' is after the current time, we've been called
997 * too early.
998 */
999 if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
1000 dev->power.timer_expires = 0;
1001 rpm_suspend(dev, dev->power.timer_autosuspends ?
1002 (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
1003 }
1004
1005 spin_unlock_irqrestore(&dev->power.lock, flags);
1006
1007 return HRTIMER_NORESTART;
1008 }
1009
1010 /**
1011 * pm_schedule_suspend - Set up a timer to submit a suspend request in future.
1012 * @dev: Device to suspend.
1013 * @delay: Time to wait before submitting a suspend request, in milliseconds.
1014 */
pm_schedule_suspend(struct device * dev,unsigned int delay)1015 int pm_schedule_suspend(struct device *dev, unsigned int delay)
1016 {
1017 unsigned long flags;
1018 u64 expires;
1019 int retval;
1020
1021 spin_lock_irqsave(&dev->power.lock, flags);
1022
1023 if (!delay) {
1024 retval = rpm_suspend(dev, RPM_ASYNC);
1025 goto out;
1026 }
1027
1028 retval = rpm_check_suspend_allowed(dev);
1029 if (retval)
1030 goto out;
1031
1032 /* Other scheduled or pending requests need to be canceled. */
1033 pm_runtime_cancel_pending(dev);
1034
1035 expires = ktime_get_mono_fast_ns() + (u64)delay * NSEC_PER_MSEC;
1036 dev->power.timer_expires = expires;
1037 dev->power.timer_autosuspends = 0;
1038 hrtimer_start(&dev->power.suspend_timer, expires, HRTIMER_MODE_ABS);
1039
1040 out:
1041 spin_unlock_irqrestore(&dev->power.lock, flags);
1042
1043 return retval;
1044 }
1045 EXPORT_SYMBOL_GPL(pm_schedule_suspend);
1046
1047 /**
1048 * __pm_runtime_idle - Entry point for runtime idle operations.
1049 * @dev: Device to send idle notification for.
1050 * @rpmflags: Flag bits.
1051 *
1052 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1053 * return immediately if it is larger than zero. Then carry out an idle
1054 * notification, either synchronous or asynchronous.
1055 *
1056 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1057 * or if pm_runtime_irq_safe() has been called.
1058 */
__pm_runtime_idle(struct device * dev,int rpmflags)1059 int __pm_runtime_idle(struct device *dev, int rpmflags)
1060 {
1061 unsigned long flags;
1062 int retval;
1063
1064 if (rpmflags & RPM_GET_PUT) {
1065 if (!atomic_dec_and_test(&dev->power.usage_count)) {
1066 trace_rpm_usage_rcuidle(dev, rpmflags);
1067 return 0;
1068 }
1069 }
1070
1071 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1072
1073 spin_lock_irqsave(&dev->power.lock, flags);
1074 retval = rpm_idle(dev, rpmflags);
1075 spin_unlock_irqrestore(&dev->power.lock, flags);
1076
1077 return retval;
1078 }
1079 EXPORT_SYMBOL_GPL(__pm_runtime_idle);
1080
1081 /**
1082 * __pm_runtime_suspend - Entry point for runtime put/suspend operations.
1083 * @dev: Device to suspend.
1084 * @rpmflags: Flag bits.
1085 *
1086 * If the RPM_GET_PUT flag is set, decrement the device's usage count and
1087 * return immediately if it is larger than zero. Then carry out a suspend,
1088 * either synchronous or asynchronous.
1089 *
1090 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1091 * or if pm_runtime_irq_safe() has been called.
1092 */
__pm_runtime_suspend(struct device * dev,int rpmflags)1093 int __pm_runtime_suspend(struct device *dev, int rpmflags)
1094 {
1095 unsigned long flags;
1096 int retval;
1097
1098 if (rpmflags & RPM_GET_PUT) {
1099 if (!atomic_dec_and_test(&dev->power.usage_count)) {
1100 trace_rpm_usage_rcuidle(dev, rpmflags);
1101 return 0;
1102 }
1103 }
1104
1105 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
1106
1107 spin_lock_irqsave(&dev->power.lock, flags);
1108 retval = rpm_suspend(dev, rpmflags);
1109 spin_unlock_irqrestore(&dev->power.lock, flags);
1110
1111 return retval;
1112 }
1113 EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
1114
1115 /**
1116 * __pm_runtime_resume - Entry point for runtime resume operations.
1117 * @dev: Device to resume.
1118 * @rpmflags: Flag bits.
1119 *
1120 * If the RPM_GET_PUT flag is set, increment the device's usage count. Then
1121 * carry out a resume, either synchronous or asynchronous.
1122 *
1123 * This routine may be called in atomic context if the RPM_ASYNC flag is set,
1124 * or if pm_runtime_irq_safe() has been called.
1125 */
__pm_runtime_resume(struct device * dev,int rpmflags)1126 int __pm_runtime_resume(struct device *dev, int rpmflags)
1127 {
1128 unsigned long flags;
1129 int retval;
1130
1131 might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe &&
1132 dev->power.runtime_status != RPM_ACTIVE);
1133
1134 if (rpmflags & RPM_GET_PUT)
1135 atomic_inc(&dev->power.usage_count);
1136
1137 spin_lock_irqsave(&dev->power.lock, flags);
1138 retval = rpm_resume(dev, rpmflags);
1139 spin_unlock_irqrestore(&dev->power.lock, flags);
1140
1141 return retval;
1142 }
1143 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
1144
1145 /**
1146 * pm_runtime_get_if_active - Conditionally bump up device usage counter.
1147 * @dev: Device to handle.
1148 * @ign_usage_count: Whether or not to look at the current usage counter value.
1149 *
1150 * Return -EINVAL if runtime PM is disabled for @dev.
1151 *
1152 * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either
1153 * @ign_usage_count is %true or the runtime PM usage counter of @dev is not
1154 * zero, increment the usage counter of @dev and return 1. Otherwise, return 0
1155 * without changing the usage counter.
1156 *
1157 * If @ign_usage_count is %true, this function can be used to prevent suspending
1158 * the device when its runtime PM status is %RPM_ACTIVE.
1159 *
1160 * If @ign_usage_count is %false, this function can be used to prevent
1161 * suspending the device when both its runtime PM status is %RPM_ACTIVE and its
1162 * runtime PM usage counter is not zero.
1163 *
1164 * The caller is resposible for decrementing the runtime PM usage counter of
1165 * @dev after this function has returned a positive value for it.
1166 */
pm_runtime_get_if_active(struct device * dev,bool ign_usage_count)1167 int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
1168 {
1169 unsigned long flags;
1170 int retval;
1171
1172 spin_lock_irqsave(&dev->power.lock, flags);
1173 if (dev->power.disable_depth > 0) {
1174 retval = -EINVAL;
1175 } else if (dev->power.runtime_status != RPM_ACTIVE) {
1176 retval = 0;
1177 } else if (ign_usage_count) {
1178 retval = 1;
1179 atomic_inc(&dev->power.usage_count);
1180 } else {
1181 retval = atomic_inc_not_zero(&dev->power.usage_count);
1182 }
1183 trace_rpm_usage_rcuidle(dev, 0);
1184 spin_unlock_irqrestore(&dev->power.lock, flags);
1185
1186 return retval;
1187 }
1188 EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
1189
1190 /**
1191 * __pm_runtime_set_status - Set runtime PM status of a device.
1192 * @dev: Device to handle.
1193 * @status: New runtime PM status of the device.
1194 *
1195 * If runtime PM of the device is disabled or its power.runtime_error field is
1196 * different from zero, the status may be changed either to RPM_ACTIVE, or to
1197 * RPM_SUSPENDED, as long as that reflects the actual state of the device.
1198 * However, if the device has a parent and the parent is not active, and the
1199 * parent's power.ignore_children flag is unset, the device's status cannot be
1200 * set to RPM_ACTIVE, so -EBUSY is returned in that case.
1201 *
1202 * If successful, __pm_runtime_set_status() clears the power.runtime_error field
1203 * and the device parent's counter of unsuspended children is modified to
1204 * reflect the new status. If the new status is RPM_SUSPENDED, an idle
1205 * notification request for the parent is submitted.
1206 *
1207 * If @dev has any suppliers (as reflected by device links to them), and @status
1208 * is RPM_ACTIVE, they will be activated upfront and if the activation of one
1209 * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead
1210 * of the @status value) and the suppliers will be deacticated on exit. The
1211 * error returned by the failing supplier activation will be returned in that
1212 * case.
1213 */
__pm_runtime_set_status(struct device * dev,unsigned int status)1214 int __pm_runtime_set_status(struct device *dev, unsigned int status)
1215 {
1216 struct device *parent = dev->parent;
1217 bool notify_parent = false;
1218 int error = 0;
1219
1220 if (status != RPM_ACTIVE && status != RPM_SUSPENDED)
1221 return -EINVAL;
1222
1223 spin_lock_irq(&dev->power.lock);
1224
1225 /*
1226 * Prevent PM-runtime from being enabled for the device or return an
1227 * error if it is enabled already and working.
1228 */
1229 if (dev->power.runtime_error || dev->power.disable_depth)
1230 dev->power.disable_depth++;
1231 else
1232 error = -EAGAIN;
1233
1234 spin_unlock_irq(&dev->power.lock);
1235
1236 if (error)
1237 return error;
1238
1239 /*
1240 * If the new status is RPM_ACTIVE, the suppliers can be activated
1241 * upfront regardless of the current status, because next time
1242 * rpm_put_suppliers() runs, the rpm_active refcounts of the links
1243 * involved will be dropped down to one anyway.
1244 */
1245 if (status == RPM_ACTIVE) {
1246 int idx = device_links_read_lock();
1247
1248 error = rpm_get_suppliers(dev);
1249 if (error)
1250 status = RPM_SUSPENDED;
1251
1252 device_links_read_unlock(idx);
1253 }
1254
1255 spin_lock_irq(&dev->power.lock);
1256
1257 if (dev->power.runtime_status == status || !parent)
1258 goto out_set;
1259
1260 if (status == RPM_SUSPENDED) {
1261 atomic_add_unless(&parent->power.child_count, -1, 0);
1262 notify_parent = !parent->power.ignore_children;
1263 } else {
1264 spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING);
1265
1266 /*
1267 * It is invalid to put an active child under a parent that is
1268 * not active, has runtime PM enabled and the
1269 * 'power.ignore_children' flag unset.
1270 */
1271 if (!parent->power.disable_depth
1272 && !parent->power.ignore_children
1273 && parent->power.runtime_status != RPM_ACTIVE) {
1274 dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n",
1275 dev_name(dev),
1276 dev_name(parent));
1277 error = -EBUSY;
1278 } else if (dev->power.runtime_status == RPM_SUSPENDED) {
1279 atomic_inc(&parent->power.child_count);
1280 }
1281
1282 spin_unlock(&parent->power.lock);
1283
1284 if (error) {
1285 status = RPM_SUSPENDED;
1286 goto out;
1287 }
1288 }
1289
1290 out_set:
1291 __update_runtime_status(dev, status);
1292 if (!error)
1293 dev->power.runtime_error = 0;
1294
1295 out:
1296 spin_unlock_irq(&dev->power.lock);
1297
1298 if (notify_parent)
1299 pm_request_idle(parent);
1300
1301 if (status == RPM_SUSPENDED) {
1302 int idx = device_links_read_lock();
1303
1304 rpm_put_suppliers(dev);
1305
1306 device_links_read_unlock(idx);
1307 }
1308
1309 pm_runtime_enable(dev);
1310
1311 return error;
1312 }
1313 EXPORT_SYMBOL_GPL(__pm_runtime_set_status);
1314
1315 /**
1316 * __pm_runtime_barrier - Cancel pending requests and wait for completions.
1317 * @dev: Device to handle.
1318 *
1319 * Flush all pending requests for the device from pm_wq and wait for all
1320 * runtime PM operations involving the device in progress to complete.
1321 *
1322 * Should be called under dev->power.lock with interrupts disabled.
1323 */
__pm_runtime_barrier(struct device * dev)1324 static void __pm_runtime_barrier(struct device *dev)
1325 {
1326 pm_runtime_deactivate_timer(dev);
1327
1328 if (dev->power.request_pending) {
1329 dev->power.request = RPM_REQ_NONE;
1330 spin_unlock_irq(&dev->power.lock);
1331
1332 cancel_work_sync(&dev->power.work);
1333
1334 spin_lock_irq(&dev->power.lock);
1335 dev->power.request_pending = false;
1336 }
1337
1338 if (dev->power.runtime_status == RPM_SUSPENDING
1339 || dev->power.runtime_status == RPM_RESUMING
1340 || dev->power.idle_notification) {
1341 DEFINE_WAIT(wait);
1342
1343 /* Suspend, wake-up or idle notification in progress. */
1344 for (;;) {
1345 prepare_to_wait(&dev->power.wait_queue, &wait,
1346 TASK_UNINTERRUPTIBLE);
1347 if (dev->power.runtime_status != RPM_SUSPENDING
1348 && dev->power.runtime_status != RPM_RESUMING
1349 && !dev->power.idle_notification)
1350 break;
1351 spin_unlock_irq(&dev->power.lock);
1352
1353 schedule();
1354
1355 spin_lock_irq(&dev->power.lock);
1356 }
1357 finish_wait(&dev->power.wait_queue, &wait);
1358 }
1359 }
1360
1361 /**
1362 * pm_runtime_barrier - Flush pending requests and wait for completions.
1363 * @dev: Device to handle.
1364 *
1365 * Prevent the device from being suspended by incrementing its usage counter and
1366 * if there's a pending resume request for the device, wake the device up.
1367 * Next, make sure that all pending requests for the device have been flushed
1368 * from pm_wq and wait for all runtime PM operations involving the device in
1369 * progress to complete.
1370 *
1371 * Return value:
1372 * 1, if there was a resume request pending and the device had to be woken up,
1373 * 0, otherwise
1374 */
pm_runtime_barrier(struct device * dev)1375 int pm_runtime_barrier(struct device *dev)
1376 {
1377 int retval = 0;
1378
1379 pm_runtime_get_noresume(dev);
1380 spin_lock_irq(&dev->power.lock);
1381
1382 if (dev->power.request_pending
1383 && dev->power.request == RPM_REQ_RESUME) {
1384 rpm_resume(dev, 0);
1385 retval = 1;
1386 }
1387
1388 __pm_runtime_barrier(dev);
1389
1390 spin_unlock_irq(&dev->power.lock);
1391 pm_runtime_put_noidle(dev);
1392
1393 return retval;
1394 }
1395 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
1396
1397 /**
1398 * __pm_runtime_disable - Disable runtime PM of a device.
1399 * @dev: Device to handle.
1400 * @check_resume: If set, check if there's a resume request for the device.
1401 *
1402 * Increment power.disable_depth for the device and if it was zero previously,
1403 * cancel all pending runtime PM requests for the device and wait for all
1404 * operations in progress to complete. The device can be either active or
1405 * suspended after its runtime PM has been disabled.
1406 *
1407 * If @check_resume is set and there's a resume request pending when
1408 * __pm_runtime_disable() is called and power.disable_depth is zero, the
1409 * function will wake up the device before disabling its runtime PM.
1410 */
__pm_runtime_disable(struct device * dev,bool check_resume)1411 void __pm_runtime_disable(struct device *dev, bool check_resume)
1412 {
1413 spin_lock_irq(&dev->power.lock);
1414
1415 if (dev->power.disable_depth > 0) {
1416 dev->power.disable_depth++;
1417 goto out;
1418 }
1419
1420 /*
1421 * Wake up the device if there's a resume request pending, because that
1422 * means there probably is some I/O to process and disabling runtime PM
1423 * shouldn't prevent the device from processing the I/O.
1424 */
1425 if (check_resume && dev->power.request_pending
1426 && dev->power.request == RPM_REQ_RESUME) {
1427 /*
1428 * Prevent suspends and idle notifications from being carried
1429 * out after we have woken up the device.
1430 */
1431 pm_runtime_get_noresume(dev);
1432
1433 rpm_resume(dev, 0);
1434
1435 pm_runtime_put_noidle(dev);
1436 }
1437
1438 /* Update time accounting before disabling PM-runtime. */
1439 update_pm_runtime_accounting(dev);
1440
1441 if (!dev->power.disable_depth++)
1442 __pm_runtime_barrier(dev);
1443
1444 out:
1445 spin_unlock_irq(&dev->power.lock);
1446 }
1447 EXPORT_SYMBOL_GPL(__pm_runtime_disable);
1448
1449 /**
1450 * pm_runtime_enable - Enable runtime PM of a device.
1451 * @dev: Device to handle.
1452 */
pm_runtime_enable(struct device * dev)1453 void pm_runtime_enable(struct device *dev)
1454 {
1455 unsigned long flags;
1456
1457 spin_lock_irqsave(&dev->power.lock, flags);
1458
1459 if (dev->power.disable_depth > 0) {
1460 dev->power.disable_depth--;
1461
1462 /* About to enable runtime pm, set accounting_timestamp to now */
1463 if (!dev->power.disable_depth)
1464 dev->power.accounting_timestamp = ktime_get_mono_fast_ns();
1465 } else {
1466 dev_warn(dev, "Unbalanced %s!\n", __func__);
1467 }
1468
1469 WARN(!dev->power.disable_depth &&
1470 dev->power.runtime_status == RPM_SUSPENDED &&
1471 !dev->power.ignore_children &&
1472 atomic_read(&dev->power.child_count) > 0,
1473 "Enabling runtime PM for inactive device (%s) with active children\n",
1474 dev_name(dev));
1475
1476 spin_unlock_irqrestore(&dev->power.lock, flags);
1477 }
1478 EXPORT_SYMBOL_GPL(pm_runtime_enable);
1479
1480 /**
1481 * pm_runtime_forbid - Block runtime PM of a device.
1482 * @dev: Device to handle.
1483 *
1484 * Increase the device's usage count and clear its power.runtime_auto flag,
1485 * so that it cannot be suspended at run time until pm_runtime_allow() is called
1486 * for it.
1487 */
pm_runtime_forbid(struct device * dev)1488 void pm_runtime_forbid(struct device *dev)
1489 {
1490 spin_lock_irq(&dev->power.lock);
1491 if (!dev->power.runtime_auto)
1492 goto out;
1493
1494 dev->power.runtime_auto = false;
1495 atomic_inc(&dev->power.usage_count);
1496 rpm_resume(dev, 0);
1497
1498 out:
1499 spin_unlock_irq(&dev->power.lock);
1500 }
1501 EXPORT_SYMBOL_GPL(pm_runtime_forbid);
1502
1503 /**
1504 * pm_runtime_allow - Unblock runtime PM of a device.
1505 * @dev: Device to handle.
1506 *
1507 * Decrease the device's usage count and set its power.runtime_auto flag.
1508 */
pm_runtime_allow(struct device * dev)1509 void pm_runtime_allow(struct device *dev)
1510 {
1511 spin_lock_irq(&dev->power.lock);
1512 if (dev->power.runtime_auto)
1513 goto out;
1514
1515 dev->power.runtime_auto = true;
1516 if (atomic_dec_and_test(&dev->power.usage_count))
1517 rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
1518 else
1519 trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC);
1520
1521 out:
1522 spin_unlock_irq(&dev->power.lock);
1523 }
1524 EXPORT_SYMBOL_GPL(pm_runtime_allow);
1525
1526 /**
1527 * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device.
1528 * @dev: Device to handle.
1529 *
1530 * Set the power.no_callbacks flag, which tells the PM core that this
1531 * device is power-managed through its parent and has no runtime PM
1532 * callbacks of its own. The runtime sysfs attributes will be removed.
1533 */
pm_runtime_no_callbacks(struct device * dev)1534 void pm_runtime_no_callbacks(struct device *dev)
1535 {
1536 spin_lock_irq(&dev->power.lock);
1537 dev->power.no_callbacks = 1;
1538 spin_unlock_irq(&dev->power.lock);
1539 if (device_is_registered(dev))
1540 rpm_sysfs_remove(dev);
1541 }
1542 EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks);
1543
1544 /**
1545 * pm_runtime_irq_safe - Leave interrupts disabled during callbacks.
1546 * @dev: Device to handle
1547 *
1548 * Set the power.irq_safe flag, which tells the PM core that the
1549 * ->runtime_suspend() and ->runtime_resume() callbacks for this device should
1550 * always be invoked with the spinlock held and interrupts disabled. It also
1551 * causes the parent's usage counter to be permanently incremented, preventing
1552 * the parent from runtime suspending -- otherwise an irq-safe child might have
1553 * to wait for a non-irq-safe parent.
1554 */
pm_runtime_irq_safe(struct device * dev)1555 void pm_runtime_irq_safe(struct device *dev)
1556 {
1557 if (dev->parent)
1558 pm_runtime_get_sync(dev->parent);
1559 spin_lock_irq(&dev->power.lock);
1560 dev->power.irq_safe = 1;
1561 spin_unlock_irq(&dev->power.lock);
1562 }
1563 EXPORT_SYMBOL_GPL(pm_runtime_irq_safe);
1564
1565 /**
1566 * update_autosuspend - Handle a change to a device's autosuspend settings.
1567 * @dev: Device to handle.
1568 * @old_delay: The former autosuspend_delay value.
1569 * @old_use: The former use_autosuspend value.
1570 *
1571 * Prevent runtime suspend if the new delay is negative and use_autosuspend is
1572 * set; otherwise allow it. Send an idle notification if suspends are allowed.
1573 *
1574 * This function must be called under dev->power.lock with interrupts disabled.
1575 */
update_autosuspend(struct device * dev,int old_delay,int old_use)1576 static void update_autosuspend(struct device *dev, int old_delay, int old_use)
1577 {
1578 int delay = dev->power.autosuspend_delay;
1579
1580 /* Should runtime suspend be prevented now? */
1581 if (dev->power.use_autosuspend && delay < 0) {
1582
1583 /* If it used to be allowed then prevent it. */
1584 if (!old_use || old_delay >= 0) {
1585 atomic_inc(&dev->power.usage_count);
1586 rpm_resume(dev, 0);
1587 } else {
1588 trace_rpm_usage_rcuidle(dev, 0);
1589 }
1590 }
1591
1592 /* Runtime suspend should be allowed now. */
1593 else {
1594
1595 /* If it used to be prevented then allow it. */
1596 if (old_use && old_delay < 0)
1597 atomic_dec(&dev->power.usage_count);
1598
1599 /* Maybe we can autosuspend now. */
1600 rpm_idle(dev, RPM_AUTO);
1601 }
1602 }
1603
1604 /**
1605 * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value.
1606 * @dev: Device to handle.
1607 * @delay: Value of the new delay in milliseconds.
1608 *
1609 * Set the device's power.autosuspend_delay value. If it changes to negative
1610 * and the power.use_autosuspend flag is set, prevent runtime suspends. If it
1611 * changes the other way, allow runtime suspends.
1612 */
pm_runtime_set_autosuspend_delay(struct device * dev,int delay)1613 void pm_runtime_set_autosuspend_delay(struct device *dev, int delay)
1614 {
1615 int old_delay, old_use;
1616
1617 spin_lock_irq(&dev->power.lock);
1618 old_delay = dev->power.autosuspend_delay;
1619 old_use = dev->power.use_autosuspend;
1620 dev->power.autosuspend_delay = delay;
1621 update_autosuspend(dev, old_delay, old_use);
1622 spin_unlock_irq(&dev->power.lock);
1623 }
1624 EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay);
1625
1626 /**
1627 * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag.
1628 * @dev: Device to handle.
1629 * @use: New value for use_autosuspend.
1630 *
1631 * Set the device's power.use_autosuspend flag, and allow or prevent runtime
1632 * suspends as needed.
1633 */
__pm_runtime_use_autosuspend(struct device * dev,bool use)1634 void __pm_runtime_use_autosuspend(struct device *dev, bool use)
1635 {
1636 int old_delay, old_use;
1637
1638 spin_lock_irq(&dev->power.lock);
1639 old_delay = dev->power.autosuspend_delay;
1640 old_use = dev->power.use_autosuspend;
1641 dev->power.use_autosuspend = use;
1642 update_autosuspend(dev, old_delay, old_use);
1643 spin_unlock_irq(&dev->power.lock);
1644 }
1645 EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
1646
1647 /**
1648 * pm_runtime_init - Initialize runtime PM fields in given device object.
1649 * @dev: Device object to initialize.
1650 */
pm_runtime_init(struct device * dev)1651 void pm_runtime_init(struct device *dev)
1652 {
1653 dev->power.runtime_status = RPM_SUSPENDED;
1654 dev->power.idle_notification = false;
1655
1656 dev->power.disable_depth = 1;
1657 atomic_set(&dev->power.usage_count, 0);
1658
1659 dev->power.runtime_error = 0;
1660
1661 atomic_set(&dev->power.child_count, 0);
1662 pm_suspend_ignore_children(dev, false);
1663 dev->power.runtime_auto = true;
1664
1665 dev->power.request_pending = false;
1666 dev->power.request = RPM_REQ_NONE;
1667 dev->power.deferred_resume = false;
1668 dev->power.needs_force_resume = 0;
1669 INIT_WORK(&dev->power.work, pm_runtime_work);
1670
1671 dev->power.timer_expires = 0;
1672 hrtimer_init(&dev->power.suspend_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1673 dev->power.suspend_timer.function = pm_suspend_timer_fn;
1674
1675 init_waitqueue_head(&dev->power.wait_queue);
1676 }
1677
1678 /**
1679 * pm_runtime_reinit - Re-initialize runtime PM fields in given device object.
1680 * @dev: Device object to re-initialize.
1681 */
pm_runtime_reinit(struct device * dev)1682 void pm_runtime_reinit(struct device *dev)
1683 {
1684 if (!pm_runtime_enabled(dev)) {
1685 if (dev->power.runtime_status == RPM_ACTIVE)
1686 pm_runtime_set_suspended(dev);
1687 if (dev->power.irq_safe) {
1688 spin_lock_irq(&dev->power.lock);
1689 dev->power.irq_safe = 0;
1690 spin_unlock_irq(&dev->power.lock);
1691 if (dev->parent)
1692 pm_runtime_put(dev->parent);
1693 }
1694 }
1695 }
1696
1697 /**
1698 * pm_runtime_remove - Prepare for removing a device from device hierarchy.
1699 * @dev: Device object being removed from device hierarchy.
1700 */
pm_runtime_remove(struct device * dev)1701 void pm_runtime_remove(struct device *dev)
1702 {
1703 __pm_runtime_disable(dev, false);
1704 pm_runtime_reinit(dev);
1705 }
1706
1707 /**
1708 * pm_runtime_get_suppliers - Resume and reference-count supplier devices.
1709 * @dev: Consumer device.
1710 */
pm_runtime_get_suppliers(struct device * dev)1711 void pm_runtime_get_suppliers(struct device *dev)
1712 {
1713 struct device_link *link;
1714 int idx;
1715
1716 idx = device_links_read_lock();
1717
1718 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1719 device_links_read_lock_held())
1720 if (link->flags & DL_FLAG_PM_RUNTIME) {
1721 link->supplier_preactivated = true;
1722 pm_runtime_get_sync(link->supplier);
1723 refcount_inc(&link->rpm_active);
1724 }
1725
1726 device_links_read_unlock(idx);
1727 }
1728
1729 /**
1730 * pm_runtime_put_suppliers - Drop references to supplier devices.
1731 * @dev: Consumer device.
1732 */
pm_runtime_put_suppliers(struct device * dev)1733 void pm_runtime_put_suppliers(struct device *dev)
1734 {
1735 struct device_link *link;
1736 unsigned long flags;
1737 bool put;
1738 int idx;
1739
1740 idx = device_links_read_lock();
1741
1742 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
1743 device_links_read_lock_held())
1744 if (link->supplier_preactivated) {
1745 link->supplier_preactivated = false;
1746 spin_lock_irqsave(&dev->power.lock, flags);
1747 put = pm_runtime_status_suspended(dev) &&
1748 refcount_dec_not_one(&link->rpm_active);
1749 spin_unlock_irqrestore(&dev->power.lock, flags);
1750 if (put)
1751 pm_runtime_put(link->supplier);
1752 }
1753
1754 device_links_read_unlock(idx);
1755 }
1756
pm_runtime_new_link(struct device * dev)1757 void pm_runtime_new_link(struct device *dev)
1758 {
1759 spin_lock_irq(&dev->power.lock);
1760 dev->power.links_count++;
1761 spin_unlock_irq(&dev->power.lock);
1762 }
1763
pm_runtime_drop_link_count(struct device * dev)1764 static void pm_runtime_drop_link_count(struct device *dev)
1765 {
1766 spin_lock_irq(&dev->power.lock);
1767 WARN_ON(dev->power.links_count == 0);
1768 dev->power.links_count--;
1769 spin_unlock_irq(&dev->power.lock);
1770 }
1771
1772 /**
1773 * pm_runtime_drop_link - Prepare for device link removal.
1774 * @link: Device link going away.
1775 *
1776 * Drop the link count of the consumer end of @link and decrement the supplier
1777 * device's runtime PM usage counter as many times as needed to drop all of the
1778 * PM runtime reference to it from the consumer.
1779 */
pm_runtime_drop_link(struct device_link * link)1780 void pm_runtime_drop_link(struct device_link *link)
1781 {
1782 if (!(link->flags & DL_FLAG_PM_RUNTIME))
1783 return;
1784
1785 pm_runtime_drop_link_count(link->consumer);
1786 pm_runtime_release_supplier(link);
1787 pm_request_idle(link->supplier);
1788 }
1789
pm_runtime_need_not_resume(struct device * dev)1790 static bool pm_runtime_need_not_resume(struct device *dev)
1791 {
1792 return atomic_read(&dev->power.usage_count) <= 1 &&
1793 (atomic_read(&dev->power.child_count) == 0 ||
1794 dev->power.ignore_children);
1795 }
1796
1797 /**
1798 * pm_runtime_force_suspend - Force a device into suspend state if needed.
1799 * @dev: Device to suspend.
1800 *
1801 * Disable runtime PM so we safely can check the device's runtime PM status and
1802 * if it is active, invoke its ->runtime_suspend callback to suspend it and
1803 * change its runtime PM status field to RPM_SUSPENDED. Also, if the device's
1804 * usage and children counters don't indicate that the device was in use before
1805 * the system-wide transition under way, decrement its parent's children counter
1806 * (if there is a parent). Keep runtime PM disabled to preserve the state
1807 * unless we encounter errors.
1808 *
1809 * Typically this function may be invoked from a system suspend callback to make
1810 * sure the device is put into low power state and it should only be used during
1811 * system-wide PM transitions to sleep states. It assumes that the analogous
1812 * pm_runtime_force_resume() will be used to resume the device.
1813 */
pm_runtime_force_suspend(struct device * dev)1814 int pm_runtime_force_suspend(struct device *dev)
1815 {
1816 int (*callback)(struct device *);
1817 int ret;
1818
1819 pm_runtime_disable(dev);
1820 if (pm_runtime_status_suspended(dev))
1821 return 0;
1822
1823 callback = RPM_GET_CALLBACK(dev, runtime_suspend);
1824
1825 ret = callback ? callback(dev) : 0;
1826 if (ret)
1827 goto err;
1828
1829 /*
1830 * If the device can stay in suspend after the system-wide transition
1831 * to the working state that will follow, drop the children counter of
1832 * its parent, but set its status to RPM_SUSPENDED anyway in case this
1833 * function will be called again for it in the meantime.
1834 */
1835 if (pm_runtime_need_not_resume(dev)) {
1836 pm_runtime_set_suspended(dev);
1837 } else {
1838 __update_runtime_status(dev, RPM_SUSPENDED);
1839 dev->power.needs_force_resume = 1;
1840 }
1841
1842 return 0;
1843
1844 err:
1845 pm_runtime_enable(dev);
1846 return ret;
1847 }
1848 EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
1849
1850 /**
1851 * pm_runtime_force_resume - Force a device into resume state if needed.
1852 * @dev: Device to resume.
1853 *
1854 * Prior invoking this function we expect the user to have brought the device
1855 * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
1856 * those actions and bring the device into full power, if it is expected to be
1857 * used on system resume. In the other case, we defer the resume to be managed
1858 * via runtime PM.
1859 *
1860 * Typically this function may be invoked from a system resume callback.
1861 */
pm_runtime_force_resume(struct device * dev)1862 int pm_runtime_force_resume(struct device *dev)
1863 {
1864 int (*callback)(struct device *);
1865 int ret = 0;
1866
1867 if (!pm_runtime_status_suspended(dev) || !dev->power.needs_force_resume)
1868 goto out;
1869
1870 /*
1871 * The value of the parent's children counter is correct already, so
1872 * just update the status of the device.
1873 */
1874 __update_runtime_status(dev, RPM_ACTIVE);
1875
1876 callback = RPM_GET_CALLBACK(dev, runtime_resume);
1877
1878 ret = callback ? callback(dev) : 0;
1879 if (ret) {
1880 pm_runtime_set_suspended(dev);
1881 goto out;
1882 }
1883
1884 pm_runtime_mark_last_busy(dev);
1885 out:
1886 dev->power.needs_force_resume = 0;
1887 pm_runtime_enable(dev);
1888 return ret;
1889 }
1890 EXPORT_SYMBOL_GPL(pm_runtime_force_resume);
1891