summaryrefslogtreecommitdiff
path: root/drivers/base/power/wakeup.c
blob: e613633ffe9cf0b7d821f69a8b5381716fb9e28e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
/*
 * drivers/base/power/wakeup.c - System wakeup events framework
 *
 * Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
 *
 * This file is released under the GPLv2.
 */

#include <linux/device.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/capability.h>
#include <linux/export.h>
#include <linux/suspend.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/pm_wakeirq.h>
#include <trace/events/power.h>

#include "power.h"

/*
 * If set, the suspend/hibernate code will abort transitions to a sleep state
 * if wakeup events are registered during or immediately before the transition.
 */
bool events_check_enabled __read_mostly;

/* First wakeup IRQ seen by the kernel in the last cycle. */
unsigned int pm_wakeup_irq __read_mostly;

/* If set and the system is suspending, terminate the suspend. */
static bool pm_abort_suspend __read_mostly;

/*
 * Combined counters of registered wakeup events and wakeup events in progress.
 * They need to be modified together atomically, so it's better to use one
 * atomic variable to hold them both.
 */
static atomic_t combined_event_count = ATOMIC_INIT(0);

#define IN_PROGRESS_BITS	(sizeof(int) * 4)
#define MAX_IN_PROGRESS		((1 << IN_PROGRESS_BITS) - 1)

static void split_counters(unsigned int *cnt, unsigned int *inpr)
{
	unsigned int comb = atomic_read(&combined_event_count);

	*cnt = (comb >> IN_PROGRESS_BITS);
	*inpr = comb & MAX_IN_PROGRESS;
}

/* A preserved old value of the events counter. */
static unsigned int saved_count;

static DEFINE_SPINLOCK(events_lock);

static void pm_wakeup_timer_fn(unsigned long data);

static LIST_HEAD(wakeup_sources);

static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);

DEFINE_STATIC_SRCU(wakeup_srcu);

static struct wakeup_source deleted_ws = {
	.name = "deleted",
	.lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
};

/**
 * wakeup_source_prepare - Prepare a new wakeup source for initialization.
 * @ws: Wakeup source to prepare.
 * @name: Pointer to the name of the new wakeup source.
 *
 * Callers must ensure that the @name string won't be freed when @ws is still in
 * use.
 */
void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
{
	if (ws) {
		memset(ws, 0, sizeof(*ws));
		ws->name = name;
	}
}
EXPORT_SYMBOL_GPL(wakeup_source_prepare);

/**
 * wakeup_source_create - Create a struct wakeup_source object.
 * @name: Name of the new wakeup source.
 */
struct wakeup_source *wakeup_source_create(const char *name)
{
	struct wakeup_source *ws;

	ws = kmalloc(sizeof(*ws), GFP_KERNEL);
	if (!ws)
		return NULL;

	wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL);
	return ws;
}
EXPORT_SYMBOL_GPL(wakeup_source_create);

/**
 * wakeup_source_drop - Prepare a struct wakeup_source object for destruction.
 * @ws: Wakeup source to prepare for destruction.
 *
 * Callers must ensure that __pm_stay_awake() or __pm_wakeup_event() will never
 * be run in parallel with this function for the same wakeup source object.
 */
void wakeup_source_drop(struct wakeup_source *ws)
{
	if (!ws)
		return;

	del_timer_sync(&ws->timer);
	__pm_relax(ws);
}
EXPORT_SYMBOL_GPL(wakeup_source_drop);

/*
 * Record wakeup_source statistics being deleted into a dummy wakeup_source.
 */
static void wakeup_source_record(struct wakeup_source *ws)
{
	unsigned long flags;

	spin_lock_irqsave(&deleted_ws.lock, flags);

	if (ws->event_count) {
		deleted_ws.total_time =
			ktime_add(deleted_ws.total_time, ws->total_time);
		deleted_ws.prevent_sleep_time =
			ktime_add(deleted_ws.prevent_sleep_time,
				  ws->prevent_sleep_time);
		deleted_ws.max_time =
			ktime_compare(deleted_ws.max_time, ws->max_time) > 0 ?
				deleted_ws.max_time : ws->max_time;
		deleted_ws.event_count += ws->event_count;
		deleted_ws.active_count += ws->active_count;
		deleted_ws.relax_count += ws->relax_count;
		deleted_ws.expire_count += ws->expire_count;
		deleted_ws.wakeup_count += ws->wakeup_count;
	}

	spin_unlock_irqrestore(&deleted_ws.lock, flags);
}

/**
 * wakeup_source_destroy - Destroy a struct wakeup_source object.
 * @ws: Wakeup source to destroy.
 *
 * Use only for wakeup source objects created with wakeup_source_create().
 */
void wakeup_source_destroy(struct wakeup_source *ws)
{
	if (!ws)
		return;

	wakeup_source_drop(ws);
	wakeup_source_record(ws);
	kfree_const(ws->name);
	kfree(ws);
}
EXPORT_SYMBOL_GPL(wakeup_source_destroy);

/**
 * wakeup_source_add - Add given object to the list of wakeup sources.
 * @ws: Wakeup source object to add to the list.
 */
void wakeup_source_add(struct wakeup_source *ws)
{
	unsigned long flags;

	if (WARN_ON(!ws))
		return;

	spin_lock_init(&ws->lock);
	setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
	ws->active = false;
	ws->last_time = ktime_get();

	spin_lock_irqsave(&events_lock, flags);
	list_add_rcu(&ws->entry, &wakeup_sources);
	spin_unlock_irqrestore(&events_lock, flags);
}
EXPORT_SYMBOL_GPL(wakeup_source_add);

/**
 * wakeup_source_remove - Remove given object from the wakeup sources list.
 * @ws: Wakeup source object to remove from the list.
 */
void wakeup_source_remove(struct wakeup_source *ws)
{
	unsigned long flags;

	if (WARN_ON(!ws))
		return;

	spin_lock_irqsave(&events_lock, flags);
	list_del_rcu(&ws->entry);
	spin_unlock_irqrestore(&events_lock, flags);
	synchronize_srcu(&wakeup_srcu);
}
EXPORT_SYMBOL_GPL(wakeup_source_remove);

/**
 * wakeup_source_register - Create wakeup source and add it to the list.
 * @name: Name of the wakeup source to register.
 */
struct wakeup_source *wakeup_source_register(const char *name)
{
	struct wakeup_source *ws;

	ws = wakeup_source_create(name);
	if (ws)
		wakeup_source_add(ws);

	return ws;
}
EXPORT_SYMBOL_GPL(wakeup_source_register);

/**
 * wakeup_source_unregister - Remove wakeup source from the list and remove it.
 * @ws: Wakeup source object to unregister.
 */
void wakeup_source_unregister(struct wakeup_source *ws)
{
	if (ws) {
		wakeup_source_remove(ws);
		wakeup_source_destroy(ws);
	}
}
EXPORT_SYMBOL_GPL(wakeup_source_unregister);

/**
 * device_wakeup_attach - Attach a wakeup source object to a device object.
 * @dev: Device to handle.
 * @ws: Wakeup source object to attach to @dev.
 *
 * This causes @dev to be treated as a wakeup device.
 */
static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
{
	spin_lock_irq(&dev->power.lock);
	if (dev->power.wakeup) {
		spin_unlock_irq(&dev->power.lock);
		return -EEXIST;
	}
	dev->power.wakeup = ws;
	spin_unlock_irq(&dev->power.lock);
	return 0;
}

/**
 * device_wakeup_enable - Enable given device to be a wakeup source.
 * @dev: Device to handle.
 *
 * Create a wakeup source object, register it and attach it to @dev.
 */
int device_wakeup_enable(struct device *dev)
{
	struct wakeup_source *ws;
	int ret;

	if (!dev || !dev->power.can_wakeup)
		return -EINVAL;

	ws = wakeup_source_register(dev_name(dev));
	if (!ws)
		return -ENOMEM;

	ret = device_wakeup_attach(dev, ws);
	if (ret)
		wakeup_source_unregister(ws);

	return ret;
}
EXPORT_SYMBOL_GPL(device_wakeup_enable);

/**
 * device_wakeup_attach_irq - Attach a wakeirq to a wakeup source
 * @dev: Device to handle
 * @wakeirq: Device specific wakeirq entry
 *
 * Attach a device wakeirq to the wakeup source so the device
 * wake IRQ can be configured automatically for suspend and
 * resume.
 *
 * Call under the device's power.lock lock.
 */
int device_wakeup_attach_irq(struct device *dev,
			     struct wake_irq *wakeirq)
{
	struct wakeup_source *ws;

	ws = dev->power.wakeup;
	if (!ws) {
		dev_err(dev, "forgot to call call device_init_wakeup?\n");
		return -EINVAL;
	}

	if (ws->wakeirq)
		return -EEXIST;

	ws->wakeirq = wakeirq;
	return 0;
}

/**
 * device_wakeup_detach_irq - Detach a wakeirq from a wakeup source
 * @dev: Device to handle
 *
 * Removes a device wakeirq from the wakeup source.
 *
 * Call under the device's power.lock lock.
 */
void device_wakeup_detach_irq(struct device *dev)
{
	struct wakeup_source *ws;

	ws = dev->power.wakeup;
	if (ws)
		ws->wakeirq = NULL;
}

/**
 * device_wakeup_arm_wake_irqs(void)
 *
 * Itereates over the list of device wakeirqs to arm them.
 */
void device_wakeup_arm_wake_irqs(void)
{
	struct wakeup_source *ws;
	int srcuidx;

	srcuidx = srcu_read_lock(&wakeup_srcu);
	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
		if (ws->wakeirq)
			dev_pm_arm_wake_irq(ws->wakeirq);
	}
	srcu_read_unlock(&wakeup_srcu, srcuidx);
}

/**
 * device_wakeup_disarm_wake_irqs(void)
 *
 * Itereates over the list of device wakeirqs to disarm them.
 */
void device_wakeup_disarm_wake_irqs(void)
{
	struct wakeup_source *ws;
	int srcuidx;

	srcuidx = srcu_read_lock(&wakeup_srcu);
	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
		if (ws->wakeirq)
			dev_pm_disarm_wake_irq(ws->wakeirq);
	}
	srcu_read_unlock(&wakeup_srcu, srcuidx);
}

/**
 * device_wakeup_detach - Detach a device's wakeup source object from it.
 * @dev: Device to detach the wakeup source object from.
 *
 * After it returns, @dev will not be treated as a wakeup device any more.
 */
static struct wakeup_source *device_wakeup_detach(struct device *dev)
{
	struct wakeup_source *ws;

	spin_lock_irq(&dev->power.lock);
	ws = dev->power.wakeup;
	dev->power.wakeup = NULL;
	spin_unlock_irq(&dev->power.lock);
	return ws;
}

/**
 * device_wakeup_disable - Do not regard a device as a wakeup source any more.
 * @dev: Device to handle.
 *
 * Detach the @dev's wakeup source object from it, unregister this wakeup source
 * object and destroy it.
 */
int device_wakeup_disable(struct device *dev)
{
	struct wakeup_source *ws;

	if (!dev || !dev->power.can_wakeup)
		return -EINVAL;

	ws = device_wakeup_detach(dev);
	if (ws)
		wakeup_source_unregister(ws);

	return 0;
}
EXPORT_SYMBOL_GPL(device_wakeup_disable);

/**
 * device_set_wakeup_capable - Set/reset device wakeup capability flag.
 * @dev: Device to handle.
 * @capable: Whether or not @dev is capable of waking up the system from sleep.
 *
 * If @capable is set, set the @dev's power.can_wakeup flag and add its
 * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
 * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
 *
 * This function may sleep and it can't be called from any context where
 * sleeping is not allowed.
 */
void device_set_wakeup_capable(struct device *dev, bool capable)
{
	if (!!dev->power.can_wakeup == !!capable)
		return;

	if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
		if (capable) {
			if (wakeup_sysfs_add(dev))
				return;
		} else {
			wakeup_sysfs_remove(dev);
		}
	}
	dev->power.can_wakeup = capable;
}
EXPORT_SYMBOL_GPL(device_set_wakeup_capable);

/**
 * device_init_wakeup - Device wakeup initialization.
 * @dev: Device to handle.
 * @enable: Whether or not to enable @dev as a wakeup device.
 *
 * By default, most devices should leave wakeup disabled.  The exceptions are
 * devices that everyone expects to be wakeup sources: keyboards, power buttons,
 * possibly network interfaces, etc.  Also, devices that don't generate their
 * own wakeup requests but merely forward requests from one bus to another
 * (like PCI bridges) should have wakeup enabled by default.
 */
int device_init_wakeup(struct device *dev, bool enable)
{
	int ret = 0;

	if (!dev)
		return -EINVAL;

	if (enable) {
		device_set_wakeup_capable(dev, true);
		ret = device_wakeup_enable(dev);
	} else {
		if (dev->power.can_wakeup)
			device_wakeup_disable(dev);

		device_set_wakeup_capable(dev, false);
	}

	return ret;
}
EXPORT_SYMBOL_GPL(device_init_wakeup);

/**
 * device_set_wakeup_enable - Enable or disable a device to wake up the system.
 * @dev: Device to handle.
 */
int device_set_wakeup_enable(struct device *dev, bool enable)
{
	if (!dev || !dev->power.can_wakeup)
		return -EINVAL;

	return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
}
EXPORT_SYMBOL_GPL(device_set_wakeup_enable);

/**
 * wakeup_source_not_registered - validate the given wakeup source.
 * @ws: Wakeup source to be validated.
 */
static bool wakeup_source_not_registered(struct wakeup_source *ws)
{
	/*
	 * Use timer struct to check if the given source is initialized
	 * by wakeup_source_add.
	 */
	return ws->timer.function != pm_wakeup_timer_fn ||
		   ws->timer.data != (unsigned long)ws;
}

/*
 * The functions below use the observation that each wakeup event starts a
 * period in which the system should not be suspended.  The moment this period
 * will end depends on how the wakeup event is going to be processed after being
 * detected and all of the possible cases can be divided into two distinct
 * groups.
 *
 * First, a wakeup event may be detected by the same functional unit that will
 * carry out the entire processing of it and possibly will pass it to user space
 * for further processing.  In that case the functional unit that has detected
 * the event may later "close" the "no suspend" period associated with it
 * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
 * pm_relax(), balanced with each other, is supposed to be used in such
 * situations.
 *
 * Second, a wakeup event may be detected by one functional unit and processed
 * by another one.  In that case the unit that has detected it cannot really
 * "close" the "no suspend" period associated with it, unless it knows in
 * advance what's going to happen to the event during processing.  This
 * knowledge, however, may not be available to it, so it can simply specify time
 * to wait before the system can be suspended and pass it as the second
 * argument of pm_wakeup_event().
 *
 * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
 * "no suspend" period will be ended either by the pm_relax(), or by the timer
 * function executed when the timer expires, whichever comes first.
 */

/**
 * wakup_source_activate - Mark given wakeup source as active.
 * @ws: Wakeup source to handle.
 *
 * Update the @ws' statistics and, if @ws has just been activated, notify the PM
 * core of the event by incrementing the counter of of wakeup events being
 * processed.
 */
static void wakeup_source_activate(struct wakeup_source *ws)
{
	unsigned int cec;

	if (WARN_ONCE(wakeup_source_not_registered(ws),
			"unregistered wakeup source\n"))
		return;

	/*
	 * active wakeup source should bring the system
	 * out of PM_SUSPEND_FREEZE state
	 */
	freeze_wake();

	ws->active = true;
	ws->active_count++;
	ws->last_time = ktime_get();
	if (ws->autosleep_enabled)
		ws->start_prevent_time = ws->last_time;

	/* Increment the counter of events in progress. */
	cec = atomic_inc_return(&combined_event_count);

	trace_wakeup_source_activate(ws->name, cec);
}

/**
 * wakeup_source_report_event - Report wakeup event using the given source.
 * @ws: Wakeup source to report the event for.
 */
static void wakeup_source_report_event(struct wakeup_source *ws)
{
	ws->event_count++;
	/* This is racy, but the counter is approximate anyway. */
	if (events_check_enabled)
		ws->wakeup_count++;

	if (!ws->active)
		wakeup_source_activate(ws);
}

/**
 * __pm_stay_awake - Notify the PM core of a wakeup event.
 * @ws: Wakeup source object associated with the source of the event.
 *
 * It is safe to call this function from interrupt context.
 */
void __pm_stay_awake(struct wakeup_source *ws)
{
	unsigned long flags;

	if (!ws)
		return;

	spin_lock_irqsave(&ws->lock, flags);

	wakeup_source_report_event(ws);
	del_timer(&ws->timer);
	ws->timer_expires = 0;

	spin_unlock_irqrestore(&ws->lock, flags);
}
EXPORT_SYMBOL_GPL(__pm_stay_awake);

/**
 * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
 * @dev: Device the wakeup event is related to.
 *
 * Notify the PM core of a wakeup event (signaled by @dev) by calling
 * __pm_stay_awake for the @dev's wakeup source object.
 *
 * Call this function after detecting of a wakeup event if pm_relax() is going
 * to be called directly after processing the event (and possibly passing it to
 * user space for further processing).
 */
void pm_stay_awake(struct device *dev)
{
	unsigned long flags;

	if (!dev)
		return;

	spin_lock_irqsave(&dev->power.lock, flags);
	__pm_stay_awake(dev->power.wakeup);
	spin_unlock_irqrestore(&dev->power.lock, flags);
}
EXPORT_SYMBOL_GPL(pm_stay_awake);

#ifdef CONFIG_PM_AUTOSLEEP
static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
{
	ktime_t delta = ktime_sub(now, ws->start_prevent_time);
	ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
}
#else
static inline void update_prevent_sleep_time(struct wakeup_source *ws,
					     ktime_t now) {}
#endif

/**
 * wakup_source_deactivate - Mark given wakeup source as inactive.
 * @ws: Wakeup source to handle.
 *
 * Update the @ws' statistics and notify the PM core that the wakeup source has
 * become inactive by decrementing the counter of wakeup events being processed
 * and incrementing the counter of registered wakeup events.
 */
static void wakeup_source_deactivate(struct wakeup_source *ws)
{
	unsigned int cnt, inpr, cec;
	ktime_t duration;
	ktime_t now;

	ws->relax_count++;
	/*
	 * __pm_relax() may be called directly or from a timer function.
	 * If it is called directly right after the timer function has been
	 * started, but before the timer function calls __pm_relax(), it is
	 * possible that __pm_stay_awake() will be called in the meantime and
	 * will set ws->active.  Then, ws->active may be cleared immediately
	 * by the __pm_relax() called from the timer function, but in such a
	 * case ws->relax_count will be different from ws->active_count.
	 */
	if (ws->relax_count != ws->active_count) {
		ws->relax_count--;
		return;
	}

	ws->active = false;

	now = ktime_get();
	duration = ktime_sub(now, ws->last_time);
	ws->total_time = ktime_add(ws->total_time, duration);
	if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
		ws->max_time = duration;

	ws->last_time = now;
	del_timer(&ws->timer);
	ws->timer_expires = 0;

	if (ws->autosleep_enabled)
		update_prevent_sleep_time(ws, now);

	/*
	 * Increment the counter of registered wakeup events and decrement the
	 * couter of wakeup events in progress simultaneously.
	 */
	cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
	trace_wakeup_source_deactivate(ws->name, cec);

	split_counters(&cnt, &inpr);
	if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
		wake_up(&wakeup_count_wait_queue);
}

/**
 * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
 * @ws: Wakeup source object associated with the source of the event.
 *
 * Call this function for wakeup events whose processing started with calling
 * __pm_stay_awake().
 *
 * It is safe to call it from interrupt context.
 */
void __pm_relax(struct wakeup_source *ws)
{
	unsigned long flags;

	if (!ws)
		return;

	spin_lock_irqsave(&ws->lock, flags);
	if (ws->active)
		wakeup_source_deactivate(ws);
	spin_unlock_irqrestore(&ws->lock, flags);
}
EXPORT_SYMBOL_GPL(__pm_relax);

/**
 * pm_relax - Notify the PM core that processing of a wakeup event has ended.
 * @dev: Device that signaled the event.
 *
 * Execute __pm_relax() for the @dev's wakeup source object.
 */
void pm_relax(struct device *dev)
{
	unsigned long flags;

	if (!dev)
		return;

	spin_lock_irqsave(&dev->power.lock, flags);
	__pm_relax(dev->power.wakeup);
	spin_unlock_irqrestore(&dev->power.lock, flags);
}
EXPORT_SYMBOL_GPL(pm_relax);

/**
 * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
 * @data: Address of the wakeup source object associated with the event source.
 *
 * Call wakeup_source_deactivate() for the wakeup source whose address is stored
 * in @data if it is currently active and its timer has not been canceled and
 * the expiration time of the timer is not in future.
 */
static void pm_wakeup_timer_fn(unsigned long data)
{
	struct wakeup_source *ws = (struct wakeup_source *)data;
	unsigned long flags;

	spin_lock_irqsave(&ws->lock, flags);

	if (ws->active && ws->timer_expires
	    && time_after_eq(jiffies, ws->timer_expires)) {
		wakeup_source_deactivate(ws);
		ws->expire_count++;
	}

	spin_unlock_irqrestore(&ws->lock, flags);
}

/**
 * __pm_wakeup_event - Notify the PM core of a wakeup event.
 * @ws: Wakeup source object associated with the event source.
 * @msec: Anticipated event processing time (in milliseconds).
 *
 * Notify the PM core of a wakeup event whose source is @ws that will take
 * approximately @msec milliseconds to be processed by the kernel.  If @ws is
 * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
 * execute pm_wakeup_timer_fn() in future.
 *
 * It is safe to call this function from interrupt context.
 */
void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
{
	unsigned long flags;
	unsigned long expires;

	if (!ws)
		return;

	spin_lock_irqsave(&ws->lock, flags);

	wakeup_source_report_event(ws);

	if (!msec) {
		wakeup_source_deactivate(ws);
		goto unlock;
	}

	expires = jiffies + msecs_to_jiffies(msec);
	if (!expires)
		expires = 1;

	if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
		mod_timer(&ws->timer, expires);
		ws->timer_expires = expires;
	}

 unlock:
	spin_unlock_irqrestore(&ws->lock, flags);
}
EXPORT_SYMBOL_GPL(__pm_wakeup_event);


/**
 * pm_wakeup_event - Notify the PM core of a wakeup event.
 * @dev: Device the wakeup event is related to.
 * @msec: Anticipated event processing time (in milliseconds).
 *
 * Call __pm_wakeup_event() for the @dev's wakeup source object.
 */
void pm_wakeup_event(struct device *dev, unsigned int msec)
{
	unsigned long flags;

	if (!dev)
		return;

	spin_lock_irqsave(&dev->power.lock, flags);
	__pm_wakeup_event(dev->power.wakeup, msec);
	spin_unlock_irqrestore(&dev->power.lock, flags);
}
EXPORT_SYMBOL_GPL(pm_wakeup_event);

void pm_print_active_wakeup_sources(void)
{
	struct wakeup_source *ws;
	int srcuidx, active = 0;
	struct wakeup_source *last_activity_ws = NULL;

	srcuidx = srcu_read_lock(&wakeup_srcu);
	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
		if (ws->active) {
			pr_info("active wakeup source: %s\n", ws->name);
			active = 1;
		} else if (!active &&
			   (!last_activity_ws ||
			    ktime_to_ns(ws->last_time) >
			    ktime_to_ns(last_activity_ws->last_time))) {
			last_activity_ws = ws;
		}
	}

	if (!active && last_activity_ws)
		pr_info("last active wakeup source: %s\n",
			last_activity_ws->name);
	srcu_read_unlock(&wakeup_srcu, srcuidx);
}
EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);

/**
 * pm_wakeup_pending - Check if power transition in progress should be aborted.
 *
 * Compare the current number of registered wakeup events with its preserved
 * value from the past and return true if new wakeup events have been registered
 * since the old value was stored.  Also return true if the current number of
 * wakeup events being processed is different from zero.
 */
bool pm_wakeup_pending(void)
{
	unsigned long flags;
	bool ret = false;

	spin_lock_irqsave(&events_lock, flags);
	if (events_check_enabled) {
		unsigned int cnt, inpr;

		split_counters(&cnt, &inpr);
		ret = (cnt != saved_count || inpr > 0);
		events_check_enabled = !ret;
	}
	spin_unlock_irqrestore(&events_lock, flags);

	if (ret) {
		pr_info("PM: Wakeup pending, aborting suspend\n");
		pm_print_active_wakeup_sources();
	}

	return ret || pm_abort_suspend;
}

void pm_system_wakeup(void)
{
	pm_abort_suspend = true;
	freeze_wake();
}
EXPORT_SYMBOL_GPL(pm_system_wakeup);

void pm_wakeup_clear(void)
{
	pm_abort_suspend = false;
	pm_wakeup_irq = 0;
}

void pm_system_irq_wakeup(unsigned int irq_number)
{
	if (pm_wakeup_irq == 0) {
		pm_wakeup_irq = irq_number;
		pm_system_wakeup();
	}
}

/**
 * pm_get_wakeup_count - Read the number of registered wakeup events.
 * @count: Address to store the value at.
 * @block: Whether or not to block.
 *
 * Store the number of registered wakeup events at the address in @count.  If
 * @block is set, block until the current number of wakeup events being
 * processed is zero.
 *
 * Return 'false' if the current number of wakeup events being processed is
 * nonzero.  Otherwise return 'true'.
 */
bool pm_get_wakeup_count(unsigned int *count, bool block)
{
	unsigned int cnt, inpr;

	if (block) {
		DEFINE_WAIT(wait);

		for (;;) {
			prepare_to_wait(&wakeup_count_wait_queue, &wait,
					TASK_INTERRUPTIBLE);
			split_counters(&cnt, &inpr);
			if (inpr == 0 || signal_pending(current))
				break;

			schedule();
		}
		finish_wait(&wakeup_count_wait_queue, &wait);
	}

	split_counters(&cnt, &inpr);
	*count = cnt;
	return !inpr;
}

/**
 * pm_save_wakeup_count - Save the current number of registered wakeup events.
 * @count: Value to compare with the current number of registered wakeup events.
 *
 * If @count is equal to the current number of registered wakeup events and the
 * current number of wakeup events being processed is zero, store @count as the
 * old number of registered wakeup events for pm_check_wakeup_events(), enable
 * wakeup events detection and return 'true'.  Otherwise disable wakeup events
 * detection and return 'false'.
 */
bool pm_save_wakeup_count(unsigned int count)
{
	unsigned int cnt, inpr;
	unsigned long flags;

	events_check_enabled = false;
	spin_lock_irqsave(&events_lock, flags);
	split_counters(&cnt, &inpr);
	if (cnt == count && inpr == 0) {
		saved_count = count;
		events_check_enabled = true;
	}
	spin_unlock_irqrestore(&events_lock, flags);
	return events_check_enabled;
}

#ifdef CONFIG_PM_AUTOSLEEP
/**
 * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
 * @enabled: Whether to set or to clear the autosleep_enabled flags.
 */
void pm_wakep_autosleep_enabled(bool set)
{
	struct wakeup_source *ws;
	ktime_t now = ktime_get();
	int srcuidx;

	srcuidx = srcu_read_lock(&wakeup_srcu);
	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
		spin_lock_irq(&ws->lock);
		if (ws->autosleep_enabled != set) {
			ws->autosleep_enabled = set;
			if (ws->active) {
				if (set)
					ws->start_prevent_time = now;
				else
					update_prevent_sleep_time(ws, now);
			}
		}
		spin_unlock_irq(&ws->lock);
	}
	srcu_read_unlock(&wakeup_srcu, srcuidx);
}
#endif /* CONFIG_PM_AUTOSLEEP */

static struct dentry *wakeup_sources_stats_dentry;

/**
 * print_wakeup_source_stats - Print wakeup source statistics information.
 * @m: seq_file to print the statistics into.
 * @ws: Wakeup source object to print the statistics for.
 */
static int print_wakeup_source_stats(struct seq_file *m,
				     struct wakeup_source *ws)
{
	unsigned long flags;
	ktime_t total_time;
	ktime_t max_time;
	unsigned long active_count;
	ktime_t active_time;
	ktime_t prevent_sleep_time;

	spin_lock_irqsave(&ws->lock, flags);

	total_time = ws->total_time;
	max_time = ws->max_time;
	prevent_sleep_time = ws->prevent_sleep_time;
	active_count = ws->active_count;
	if (ws->active) {
		ktime_t now = ktime_get();

		active_time = ktime_sub(now, ws->last_time);
		total_time = ktime_add(total_time, active_time);
		if (active_time.tv64 > max_time.tv64)
			max_time = active_time;

		if (ws->autosleep_enabled)
			prevent_sleep_time = ktime_add(prevent_sleep_time,
				ktime_sub(now, ws->start_prevent_time));
	} else {
		active_time = ktime_set(0, 0);
	}

	seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t%lu\t\t%lld\t\t%lld\t\t%lld\t\t%lld\t\t%lld\n",
		   ws->name, active_count, ws->event_count,
		   ws->wakeup_count, ws->expire_count,
		   ktime_to_ms(active_time), ktime_to_ms(total_time),
		   ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
		   ktime_to_ms(prevent_sleep_time));

	spin_unlock_irqrestore(&ws->lock, flags);

	return 0;
}

/**
 * wakeup_sources_stats_show - Print wakeup sources statistics information.
 * @m: seq_file to print the statistics into.
 */
static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
{
	struct wakeup_source *ws;
	int srcuidx;

	seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
		"expire_count\tactive_since\ttotal_time\tmax_time\t"
		"last_change\tprevent_suspend_time\n");

	srcuidx = srcu_read_lock(&wakeup_srcu);
	list_for_each_entry_rcu(ws, &wakeup_sources, entry)
		print_wakeup_source_stats(m, ws);
	srcu_read_unlock(&wakeup_srcu, srcuidx);

	print_wakeup_source_stats(m, &deleted_ws);

	return 0;
}

static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
{
	return single_open(file, wakeup_sources_stats_show, NULL);
}

static const struct file_operations wakeup_sources_stats_fops = {
	.owner = THIS_MODULE,
	.open = wakeup_sources_stats_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int __init wakeup_sources_debugfs_init(void)
{
	wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
			S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
	return 0;
}

postcore_initcall(wakeup_sources_debugfs_init);