xref: /openbmc/linux/drivers/base/power/wakeup.c (revision 4da722ca)
1 /*
2  * drivers/base/power/wakeup.c - System wakeup events framework
3  *
4  * Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5  *
6  * This file is released under the GPLv2.
7  */
8 
9 #include <linux/device.h>
10 #include <linux/slab.h>
11 #include <linux/sched/signal.h>
12 #include <linux/capability.h>
13 #include <linux/export.h>
14 #include <linux/suspend.h>
15 #include <linux/seq_file.h>
16 #include <linux/debugfs.h>
17 #include <linux/pm_wakeirq.h>
18 #include <trace/events/power.h>
19 
20 #include "power.h"
21 
22 /*
23  * If set, the suspend/hibernate code will abort transitions to a sleep state
24  * if wakeup events are registered during or immediately before the transition.
25  */
26 bool events_check_enabled __read_mostly;
27 
28 /* First wakeup IRQ seen by the kernel in the last cycle. */
29 unsigned int pm_wakeup_irq __read_mostly;
30 
31 /* If greater than 0 and the system is suspending, terminate the suspend. */
32 static atomic_t pm_abort_suspend __read_mostly;
33 
34 /*
35  * Combined counters of registered wakeup events and wakeup events in progress.
36  * They need to be modified together atomically, so it's better to use one
37  * atomic variable to hold them both.
38  */
39 static atomic_t combined_event_count = ATOMIC_INIT(0);
40 
41 #define IN_PROGRESS_BITS	(sizeof(int) * 4)
42 #define MAX_IN_PROGRESS		((1 << IN_PROGRESS_BITS) - 1)
43 
44 static void split_counters(unsigned int *cnt, unsigned int *inpr)
45 {
46 	unsigned int comb = atomic_read(&combined_event_count);
47 
48 	*cnt = (comb >> IN_PROGRESS_BITS);
49 	*inpr = comb & MAX_IN_PROGRESS;
50 }
51 
52 /* A preserved old value of the events counter. */
53 static unsigned int saved_count;
54 
55 static DEFINE_SPINLOCK(events_lock);
56 
57 static void pm_wakeup_timer_fn(unsigned long data);
58 
59 static LIST_HEAD(wakeup_sources);
60 
61 static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
62 
63 DEFINE_STATIC_SRCU(wakeup_srcu);
64 
65 static struct wakeup_source deleted_ws = {
66 	.name = "deleted",
67 	.lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
68 };
69 
70 /**
71  * wakeup_source_prepare - Prepare a new wakeup source for initialization.
72  * @ws: Wakeup source to prepare.
73  * @name: Pointer to the name of the new wakeup source.
74  *
75  * Callers must ensure that the @name string won't be freed when @ws is still in
76  * use.
77  */
78 void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
79 {
80 	if (ws) {
81 		memset(ws, 0, sizeof(*ws));
82 		ws->name = name;
83 	}
84 }
85 EXPORT_SYMBOL_GPL(wakeup_source_prepare);
86 
87 /**
88  * wakeup_source_create - Create a struct wakeup_source object.
89  * @name: Name of the new wakeup source.
90  */
91 struct wakeup_source *wakeup_source_create(const char *name)
92 {
93 	struct wakeup_source *ws;
94 
95 	ws = kmalloc(sizeof(*ws), GFP_KERNEL);
96 	if (!ws)
97 		return NULL;
98 
99 	wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL);
100 	return ws;
101 }
102 EXPORT_SYMBOL_GPL(wakeup_source_create);
103 
104 /**
105  * wakeup_source_drop - Prepare a struct wakeup_source object for destruction.
106  * @ws: Wakeup source to prepare for destruction.
107  *
108  * Callers must ensure that __pm_stay_awake() or __pm_wakeup_event() will never
109  * be run in parallel with this function for the same wakeup source object.
110  */
111 void wakeup_source_drop(struct wakeup_source *ws)
112 {
113 	if (!ws)
114 		return;
115 
116 	del_timer_sync(&ws->timer);
117 	__pm_relax(ws);
118 }
119 EXPORT_SYMBOL_GPL(wakeup_source_drop);
120 
121 /*
122  * Record wakeup_source statistics being deleted into a dummy wakeup_source.
123  */
124 static void wakeup_source_record(struct wakeup_source *ws)
125 {
126 	unsigned long flags;
127 
128 	spin_lock_irqsave(&deleted_ws.lock, flags);
129 
130 	if (ws->event_count) {
131 		deleted_ws.total_time =
132 			ktime_add(deleted_ws.total_time, ws->total_time);
133 		deleted_ws.prevent_sleep_time =
134 			ktime_add(deleted_ws.prevent_sleep_time,
135 				  ws->prevent_sleep_time);
136 		deleted_ws.max_time =
137 			ktime_compare(deleted_ws.max_time, ws->max_time) > 0 ?
138 				deleted_ws.max_time : ws->max_time;
139 		deleted_ws.event_count += ws->event_count;
140 		deleted_ws.active_count += ws->active_count;
141 		deleted_ws.relax_count += ws->relax_count;
142 		deleted_ws.expire_count += ws->expire_count;
143 		deleted_ws.wakeup_count += ws->wakeup_count;
144 	}
145 
146 	spin_unlock_irqrestore(&deleted_ws.lock, flags);
147 }
148 
149 /**
150  * wakeup_source_destroy - Destroy a struct wakeup_source object.
151  * @ws: Wakeup source to destroy.
152  *
153  * Use only for wakeup source objects created with wakeup_source_create().
154  */
155 void wakeup_source_destroy(struct wakeup_source *ws)
156 {
157 	if (!ws)
158 		return;
159 
160 	wakeup_source_drop(ws);
161 	wakeup_source_record(ws);
162 	kfree_const(ws->name);
163 	kfree(ws);
164 }
165 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
166 
167 /**
168  * wakeup_source_add - Add given object to the list of wakeup sources.
169  * @ws: Wakeup source object to add to the list.
170  */
171 void wakeup_source_add(struct wakeup_source *ws)
172 {
173 	unsigned long flags;
174 
175 	if (WARN_ON(!ws))
176 		return;
177 
178 	spin_lock_init(&ws->lock);
179 	setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
180 	ws->active = false;
181 	ws->last_time = ktime_get();
182 
183 	spin_lock_irqsave(&events_lock, flags);
184 	list_add_rcu(&ws->entry, &wakeup_sources);
185 	spin_unlock_irqrestore(&events_lock, flags);
186 }
187 EXPORT_SYMBOL_GPL(wakeup_source_add);
188 
189 /**
190  * wakeup_source_remove - Remove given object from the wakeup sources list.
191  * @ws: Wakeup source object to remove from the list.
192  */
193 void wakeup_source_remove(struct wakeup_source *ws)
194 {
195 	unsigned long flags;
196 
197 	if (WARN_ON(!ws))
198 		return;
199 
200 	spin_lock_irqsave(&events_lock, flags);
201 	list_del_rcu(&ws->entry);
202 	spin_unlock_irqrestore(&events_lock, flags);
203 	synchronize_srcu(&wakeup_srcu);
204 }
205 EXPORT_SYMBOL_GPL(wakeup_source_remove);
206 
207 /**
208  * wakeup_source_register - Create wakeup source and add it to the list.
209  * @name: Name of the wakeup source to register.
210  */
211 struct wakeup_source *wakeup_source_register(const char *name)
212 {
213 	struct wakeup_source *ws;
214 
215 	ws = wakeup_source_create(name);
216 	if (ws)
217 		wakeup_source_add(ws);
218 
219 	return ws;
220 }
221 EXPORT_SYMBOL_GPL(wakeup_source_register);
222 
223 /**
224  * wakeup_source_unregister - Remove wakeup source from the list and remove it.
225  * @ws: Wakeup source object to unregister.
226  */
227 void wakeup_source_unregister(struct wakeup_source *ws)
228 {
229 	if (ws) {
230 		wakeup_source_remove(ws);
231 		wakeup_source_destroy(ws);
232 	}
233 }
234 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
235 
236 /**
237  * device_wakeup_attach - Attach a wakeup source object to a device object.
238  * @dev: Device to handle.
239  * @ws: Wakeup source object to attach to @dev.
240  *
241  * This causes @dev to be treated as a wakeup device.
242  */
243 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
244 {
245 	spin_lock_irq(&dev->power.lock);
246 	if (dev->power.wakeup) {
247 		spin_unlock_irq(&dev->power.lock);
248 		return -EEXIST;
249 	}
250 	dev->power.wakeup = ws;
251 	if (dev->power.wakeirq)
252 		device_wakeup_attach_irq(dev, dev->power.wakeirq);
253 	spin_unlock_irq(&dev->power.lock);
254 	return 0;
255 }
256 
257 /**
258  * device_wakeup_enable - Enable given device to be a wakeup source.
259  * @dev: Device to handle.
260  *
261  * Create a wakeup source object, register it and attach it to @dev.
262  */
263 int device_wakeup_enable(struct device *dev)
264 {
265 	struct wakeup_source *ws;
266 	int ret;
267 
268 	if (!dev || !dev->power.can_wakeup)
269 		return -EINVAL;
270 
271 	ws = wakeup_source_register(dev_name(dev));
272 	if (!ws)
273 		return -ENOMEM;
274 
275 	ret = device_wakeup_attach(dev, ws);
276 	if (ret)
277 		wakeup_source_unregister(ws);
278 
279 	return ret;
280 }
281 EXPORT_SYMBOL_GPL(device_wakeup_enable);
282 
283 /**
284  * device_wakeup_attach_irq - Attach a wakeirq to a wakeup source
285  * @dev: Device to handle
286  * @wakeirq: Device specific wakeirq entry
287  *
288  * Attach a device wakeirq to the wakeup source so the device
289  * wake IRQ can be configured automatically for suspend and
290  * resume.
291  *
292  * Call under the device's power.lock lock.
293  */
294 int device_wakeup_attach_irq(struct device *dev,
295 			     struct wake_irq *wakeirq)
296 {
297 	struct wakeup_source *ws;
298 
299 	ws = dev->power.wakeup;
300 	if (!ws) {
301 		dev_err(dev, "forgot to call call device_init_wakeup?\n");
302 		return -EINVAL;
303 	}
304 
305 	if (ws->wakeirq)
306 		return -EEXIST;
307 
308 	ws->wakeirq = wakeirq;
309 	return 0;
310 }
311 
312 /**
313  * device_wakeup_detach_irq - Detach a wakeirq from a wakeup source
314  * @dev: Device to handle
315  *
316  * Removes a device wakeirq from the wakeup source.
317  *
318  * Call under the device's power.lock lock.
319  */
320 void device_wakeup_detach_irq(struct device *dev)
321 {
322 	struct wakeup_source *ws;
323 
324 	ws = dev->power.wakeup;
325 	if (ws)
326 		ws->wakeirq = NULL;
327 }
328 
329 /**
330  * device_wakeup_arm_wake_irqs(void)
331  *
332  * Itereates over the list of device wakeirqs to arm them.
333  */
334 void device_wakeup_arm_wake_irqs(void)
335 {
336 	struct wakeup_source *ws;
337 	int srcuidx;
338 
339 	srcuidx = srcu_read_lock(&wakeup_srcu);
340 	list_for_each_entry_rcu(ws, &wakeup_sources, entry)
341 		dev_pm_arm_wake_irq(ws->wakeirq);
342 	srcu_read_unlock(&wakeup_srcu, srcuidx);
343 }
344 
345 /**
346  * device_wakeup_disarm_wake_irqs(void)
347  *
348  * Itereates over the list of device wakeirqs to disarm them.
349  */
350 void device_wakeup_disarm_wake_irqs(void)
351 {
352 	struct wakeup_source *ws;
353 	int srcuidx;
354 
355 	srcuidx = srcu_read_lock(&wakeup_srcu);
356 	list_for_each_entry_rcu(ws, &wakeup_sources, entry)
357 		dev_pm_disarm_wake_irq(ws->wakeirq);
358 	srcu_read_unlock(&wakeup_srcu, srcuidx);
359 }
360 
361 /**
362  * device_wakeup_detach - Detach a device's wakeup source object from it.
363  * @dev: Device to detach the wakeup source object from.
364  *
365  * After it returns, @dev will not be treated as a wakeup device any more.
366  */
367 static struct wakeup_source *device_wakeup_detach(struct device *dev)
368 {
369 	struct wakeup_source *ws;
370 
371 	spin_lock_irq(&dev->power.lock);
372 	ws = dev->power.wakeup;
373 	dev->power.wakeup = NULL;
374 	spin_unlock_irq(&dev->power.lock);
375 	return ws;
376 }
377 
378 /**
379  * device_wakeup_disable - Do not regard a device as a wakeup source any more.
380  * @dev: Device to handle.
381  *
382  * Detach the @dev's wakeup source object from it, unregister this wakeup source
383  * object and destroy it.
384  */
385 int device_wakeup_disable(struct device *dev)
386 {
387 	struct wakeup_source *ws;
388 
389 	if (!dev || !dev->power.can_wakeup)
390 		return -EINVAL;
391 
392 	ws = device_wakeup_detach(dev);
393 	wakeup_source_unregister(ws);
394 	return 0;
395 }
396 EXPORT_SYMBOL_GPL(device_wakeup_disable);
397 
398 /**
399  * device_set_wakeup_capable - Set/reset device wakeup capability flag.
400  * @dev: Device to handle.
401  * @capable: Whether or not @dev is capable of waking up the system from sleep.
402  *
403  * If @capable is set, set the @dev's power.can_wakeup flag and add its
404  * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
405  * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
406  *
407  * This function may sleep and it can't be called from any context where
408  * sleeping is not allowed.
409  */
410 void device_set_wakeup_capable(struct device *dev, bool capable)
411 {
412 	if (!!dev->power.can_wakeup == !!capable)
413 		return;
414 
415 	if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
416 		if (capable) {
417 			if (wakeup_sysfs_add(dev))
418 				return;
419 		} else {
420 			wakeup_sysfs_remove(dev);
421 		}
422 	}
423 	dev->power.can_wakeup = capable;
424 }
425 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
426 
427 /**
428  * device_init_wakeup - Device wakeup initialization.
429  * @dev: Device to handle.
430  * @enable: Whether or not to enable @dev as a wakeup device.
431  *
432  * By default, most devices should leave wakeup disabled.  The exceptions are
433  * devices that everyone expects to be wakeup sources: keyboards, power buttons,
434  * possibly network interfaces, etc.  Also, devices that don't generate their
435  * own wakeup requests but merely forward requests from one bus to another
436  * (like PCI bridges) should have wakeup enabled by default.
437  */
438 int device_init_wakeup(struct device *dev, bool enable)
439 {
440 	int ret = 0;
441 
442 	if (!dev)
443 		return -EINVAL;
444 
445 	if (enable) {
446 		device_set_wakeup_capable(dev, true);
447 		ret = device_wakeup_enable(dev);
448 	} else {
449 		if (dev->power.can_wakeup)
450 			device_wakeup_disable(dev);
451 
452 		device_set_wakeup_capable(dev, false);
453 	}
454 
455 	return ret;
456 }
457 EXPORT_SYMBOL_GPL(device_init_wakeup);
458 
459 /**
460  * device_set_wakeup_enable - Enable or disable a device to wake up the system.
461  * @dev: Device to handle.
462  */
463 int device_set_wakeup_enable(struct device *dev, bool enable)
464 {
465 	if (!dev || !dev->power.can_wakeup)
466 		return -EINVAL;
467 
468 	return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
469 }
470 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
471 
472 /**
473  * wakeup_source_not_registered - validate the given wakeup source.
474  * @ws: Wakeup source to be validated.
475  */
476 static bool wakeup_source_not_registered(struct wakeup_source *ws)
477 {
478 	/*
479 	 * Use timer struct to check if the given source is initialized
480 	 * by wakeup_source_add.
481 	 */
482 	return ws->timer.function != pm_wakeup_timer_fn ||
483 		   ws->timer.data != (unsigned long)ws;
484 }
485 
486 /*
487  * The functions below use the observation that each wakeup event starts a
488  * period in which the system should not be suspended.  The moment this period
489  * will end depends on how the wakeup event is going to be processed after being
490  * detected and all of the possible cases can be divided into two distinct
491  * groups.
492  *
493  * First, a wakeup event may be detected by the same functional unit that will
494  * carry out the entire processing of it and possibly will pass it to user space
495  * for further processing.  In that case the functional unit that has detected
496  * the event may later "close" the "no suspend" period associated with it
497  * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
498  * pm_relax(), balanced with each other, is supposed to be used in such
499  * situations.
500  *
501  * Second, a wakeup event may be detected by one functional unit and processed
502  * by another one.  In that case the unit that has detected it cannot really
503  * "close" the "no suspend" period associated with it, unless it knows in
504  * advance what's going to happen to the event during processing.  This
505  * knowledge, however, may not be available to it, so it can simply specify time
506  * to wait before the system can be suspended and pass it as the second
507  * argument of pm_wakeup_event().
508  *
509  * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
510  * "no suspend" period will be ended either by the pm_relax(), or by the timer
511  * function executed when the timer expires, whichever comes first.
512  */
513 
514 /**
515  * wakup_source_activate - Mark given wakeup source as active.
516  * @ws: Wakeup source to handle.
517  *
518  * Update the @ws' statistics and, if @ws has just been activated, notify the PM
519  * core of the event by incrementing the counter of of wakeup events being
520  * processed.
521  */
522 static void wakeup_source_activate(struct wakeup_source *ws)
523 {
524 	unsigned int cec;
525 
526 	if (WARN_ONCE(wakeup_source_not_registered(ws),
527 			"unregistered wakeup source\n"))
528 		return;
529 
530 	ws->active = true;
531 	ws->active_count++;
532 	ws->last_time = ktime_get();
533 	if (ws->autosleep_enabled)
534 		ws->start_prevent_time = ws->last_time;
535 
536 	/* Increment the counter of events in progress. */
537 	cec = atomic_inc_return(&combined_event_count);
538 
539 	trace_wakeup_source_activate(ws->name, cec);
540 }
541 
542 /**
543  * wakeup_source_report_event - Report wakeup event using the given source.
544  * @ws: Wakeup source to report the event for.
545  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
546  */
547 static void wakeup_source_report_event(struct wakeup_source *ws, bool hard)
548 {
549 	ws->event_count++;
550 	/* This is racy, but the counter is approximate anyway. */
551 	if (events_check_enabled)
552 		ws->wakeup_count++;
553 
554 	if (!ws->active)
555 		wakeup_source_activate(ws);
556 
557 	if (hard)
558 		pm_system_wakeup();
559 }
560 
561 /**
562  * __pm_stay_awake - Notify the PM core of a wakeup event.
563  * @ws: Wakeup source object associated with the source of the event.
564  *
565  * It is safe to call this function from interrupt context.
566  */
567 void __pm_stay_awake(struct wakeup_source *ws)
568 {
569 	unsigned long flags;
570 
571 	if (!ws)
572 		return;
573 
574 	spin_lock_irqsave(&ws->lock, flags);
575 
576 	wakeup_source_report_event(ws, false);
577 	del_timer(&ws->timer);
578 	ws->timer_expires = 0;
579 
580 	spin_unlock_irqrestore(&ws->lock, flags);
581 }
582 EXPORT_SYMBOL_GPL(__pm_stay_awake);
583 
584 /**
585  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
586  * @dev: Device the wakeup event is related to.
587  *
588  * Notify the PM core of a wakeup event (signaled by @dev) by calling
589  * __pm_stay_awake for the @dev's wakeup source object.
590  *
591  * Call this function after detecting of a wakeup event if pm_relax() is going
592  * to be called directly after processing the event (and possibly passing it to
593  * user space for further processing).
594  */
595 void pm_stay_awake(struct device *dev)
596 {
597 	unsigned long flags;
598 
599 	if (!dev)
600 		return;
601 
602 	spin_lock_irqsave(&dev->power.lock, flags);
603 	__pm_stay_awake(dev->power.wakeup);
604 	spin_unlock_irqrestore(&dev->power.lock, flags);
605 }
606 EXPORT_SYMBOL_GPL(pm_stay_awake);
607 
608 #ifdef CONFIG_PM_AUTOSLEEP
609 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
610 {
611 	ktime_t delta = ktime_sub(now, ws->start_prevent_time);
612 	ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
613 }
614 #else
615 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
616 					     ktime_t now) {}
617 #endif
618 
619 /**
620  * wakup_source_deactivate - Mark given wakeup source as inactive.
621  * @ws: Wakeup source to handle.
622  *
623  * Update the @ws' statistics and notify the PM core that the wakeup source has
624  * become inactive by decrementing the counter of wakeup events being processed
625  * and incrementing the counter of registered wakeup events.
626  */
627 static void wakeup_source_deactivate(struct wakeup_source *ws)
628 {
629 	unsigned int cnt, inpr, cec;
630 	ktime_t duration;
631 	ktime_t now;
632 
633 	ws->relax_count++;
634 	/*
635 	 * __pm_relax() may be called directly or from a timer function.
636 	 * If it is called directly right after the timer function has been
637 	 * started, but before the timer function calls __pm_relax(), it is
638 	 * possible that __pm_stay_awake() will be called in the meantime and
639 	 * will set ws->active.  Then, ws->active may be cleared immediately
640 	 * by the __pm_relax() called from the timer function, but in such a
641 	 * case ws->relax_count will be different from ws->active_count.
642 	 */
643 	if (ws->relax_count != ws->active_count) {
644 		ws->relax_count--;
645 		return;
646 	}
647 
648 	ws->active = false;
649 
650 	now = ktime_get();
651 	duration = ktime_sub(now, ws->last_time);
652 	ws->total_time = ktime_add(ws->total_time, duration);
653 	if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
654 		ws->max_time = duration;
655 
656 	ws->last_time = now;
657 	del_timer(&ws->timer);
658 	ws->timer_expires = 0;
659 
660 	if (ws->autosleep_enabled)
661 		update_prevent_sleep_time(ws, now);
662 
663 	/*
664 	 * Increment the counter of registered wakeup events and decrement the
665 	 * couter of wakeup events in progress simultaneously.
666 	 */
667 	cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
668 	trace_wakeup_source_deactivate(ws->name, cec);
669 
670 	split_counters(&cnt, &inpr);
671 	if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
672 		wake_up(&wakeup_count_wait_queue);
673 }
674 
675 /**
676  * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
677  * @ws: Wakeup source object associated with the source of the event.
678  *
679  * Call this function for wakeup events whose processing started with calling
680  * __pm_stay_awake().
681  *
682  * It is safe to call it from interrupt context.
683  */
684 void __pm_relax(struct wakeup_source *ws)
685 {
686 	unsigned long flags;
687 
688 	if (!ws)
689 		return;
690 
691 	spin_lock_irqsave(&ws->lock, flags);
692 	if (ws->active)
693 		wakeup_source_deactivate(ws);
694 	spin_unlock_irqrestore(&ws->lock, flags);
695 }
696 EXPORT_SYMBOL_GPL(__pm_relax);
697 
698 /**
699  * pm_relax - Notify the PM core that processing of a wakeup event has ended.
700  * @dev: Device that signaled the event.
701  *
702  * Execute __pm_relax() for the @dev's wakeup source object.
703  */
704 void pm_relax(struct device *dev)
705 {
706 	unsigned long flags;
707 
708 	if (!dev)
709 		return;
710 
711 	spin_lock_irqsave(&dev->power.lock, flags);
712 	__pm_relax(dev->power.wakeup);
713 	spin_unlock_irqrestore(&dev->power.lock, flags);
714 }
715 EXPORT_SYMBOL_GPL(pm_relax);
716 
717 /**
718  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
719  * @data: Address of the wakeup source object associated with the event source.
720  *
721  * Call wakeup_source_deactivate() for the wakeup source whose address is stored
722  * in @data if it is currently active and its timer has not been canceled and
723  * the expiration time of the timer is not in future.
724  */
725 static void pm_wakeup_timer_fn(unsigned long data)
726 {
727 	struct wakeup_source *ws = (struct wakeup_source *)data;
728 	unsigned long flags;
729 
730 	spin_lock_irqsave(&ws->lock, flags);
731 
732 	if (ws->active && ws->timer_expires
733 	    && time_after_eq(jiffies, ws->timer_expires)) {
734 		wakeup_source_deactivate(ws);
735 		ws->expire_count++;
736 	}
737 
738 	spin_unlock_irqrestore(&ws->lock, flags);
739 }
740 
741 /**
742  * pm_wakeup_ws_event - Notify the PM core of a wakeup event.
743  * @ws: Wakeup source object associated with the event source.
744  * @msec: Anticipated event processing time (in milliseconds).
745  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
746  *
747  * Notify the PM core of a wakeup event whose source is @ws that will take
748  * approximately @msec milliseconds to be processed by the kernel.  If @ws is
749  * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
750  * execute pm_wakeup_timer_fn() in future.
751  *
752  * It is safe to call this function from interrupt context.
753  */
754 void pm_wakeup_ws_event(struct wakeup_source *ws, unsigned int msec, bool hard)
755 {
756 	unsigned long flags;
757 	unsigned long expires;
758 
759 	if (!ws)
760 		return;
761 
762 	spin_lock_irqsave(&ws->lock, flags);
763 
764 	wakeup_source_report_event(ws, hard);
765 
766 	if (!msec) {
767 		wakeup_source_deactivate(ws);
768 		goto unlock;
769 	}
770 
771 	expires = jiffies + msecs_to_jiffies(msec);
772 	if (!expires)
773 		expires = 1;
774 
775 	if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
776 		mod_timer(&ws->timer, expires);
777 		ws->timer_expires = expires;
778 	}
779 
780  unlock:
781 	spin_unlock_irqrestore(&ws->lock, flags);
782 }
783 EXPORT_SYMBOL_GPL(pm_wakeup_ws_event);
784 
785 /**
786  * pm_wakeup_event - Notify the PM core of a wakeup event.
787  * @dev: Device the wakeup event is related to.
788  * @msec: Anticipated event processing time (in milliseconds).
789  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
790  *
791  * Call pm_wakeup_ws_event() for the @dev's wakeup source object.
792  */
793 void pm_wakeup_dev_event(struct device *dev, unsigned int msec, bool hard)
794 {
795 	unsigned long flags;
796 
797 	if (!dev)
798 		return;
799 
800 	spin_lock_irqsave(&dev->power.lock, flags);
801 	pm_wakeup_ws_event(dev->power.wakeup, msec, hard);
802 	spin_unlock_irqrestore(&dev->power.lock, flags);
803 }
804 EXPORT_SYMBOL_GPL(pm_wakeup_dev_event);
805 
806 void pm_print_active_wakeup_sources(void)
807 {
808 	struct wakeup_source *ws;
809 	int srcuidx, active = 0;
810 	struct wakeup_source *last_activity_ws = NULL;
811 
812 	srcuidx = srcu_read_lock(&wakeup_srcu);
813 	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
814 		if (ws->active) {
815 			pr_debug("active wakeup source: %s\n", ws->name);
816 			active = 1;
817 		} else if (!active &&
818 			   (!last_activity_ws ||
819 			    ktime_to_ns(ws->last_time) >
820 			    ktime_to_ns(last_activity_ws->last_time))) {
821 			last_activity_ws = ws;
822 		}
823 	}
824 
825 	if (!active && last_activity_ws)
826 		pr_debug("last active wakeup source: %s\n",
827 			last_activity_ws->name);
828 	srcu_read_unlock(&wakeup_srcu, srcuidx);
829 }
830 EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);
831 
832 /**
833  * pm_wakeup_pending - Check if power transition in progress should be aborted.
834  *
835  * Compare the current number of registered wakeup events with its preserved
836  * value from the past and return true if new wakeup events have been registered
837  * since the old value was stored.  Also return true if the current number of
838  * wakeup events being processed is different from zero.
839  */
840 bool pm_wakeup_pending(void)
841 {
842 	unsigned long flags;
843 	bool ret = false;
844 
845 	spin_lock_irqsave(&events_lock, flags);
846 	if (events_check_enabled) {
847 		unsigned int cnt, inpr;
848 
849 		split_counters(&cnt, &inpr);
850 		ret = (cnt != saved_count || inpr > 0);
851 		events_check_enabled = !ret;
852 	}
853 	spin_unlock_irqrestore(&events_lock, flags);
854 
855 	if (ret) {
856 		pr_info("PM: Wakeup pending, aborting suspend\n");
857 		pm_print_active_wakeup_sources();
858 	}
859 
860 	return ret || atomic_read(&pm_abort_suspend) > 0;
861 }
862 
863 void pm_system_wakeup(void)
864 {
865 	atomic_inc(&pm_abort_suspend);
866 	freeze_wake();
867 }
868 EXPORT_SYMBOL_GPL(pm_system_wakeup);
869 
870 void pm_system_cancel_wakeup(void)
871 {
872 	atomic_dec(&pm_abort_suspend);
873 }
874 
875 void pm_wakeup_clear(bool reset)
876 {
877 	pm_wakeup_irq = 0;
878 	if (reset)
879 		atomic_set(&pm_abort_suspend, 0);
880 }
881 
882 void pm_system_irq_wakeup(unsigned int irq_number)
883 {
884 	if (pm_wakeup_irq == 0) {
885 		pm_wakeup_irq = irq_number;
886 		pm_system_wakeup();
887 	}
888 }
889 
890 /**
891  * pm_get_wakeup_count - Read the number of registered wakeup events.
892  * @count: Address to store the value at.
893  * @block: Whether or not to block.
894  *
895  * Store the number of registered wakeup events at the address in @count.  If
896  * @block is set, block until the current number of wakeup events being
897  * processed is zero.
898  *
899  * Return 'false' if the current number of wakeup events being processed is
900  * nonzero.  Otherwise return 'true'.
901  */
902 bool pm_get_wakeup_count(unsigned int *count, bool block)
903 {
904 	unsigned int cnt, inpr;
905 
906 	if (block) {
907 		DEFINE_WAIT(wait);
908 
909 		for (;;) {
910 			prepare_to_wait(&wakeup_count_wait_queue, &wait,
911 					TASK_INTERRUPTIBLE);
912 			split_counters(&cnt, &inpr);
913 			if (inpr == 0 || signal_pending(current))
914 				break;
915 			pm_print_active_wakeup_sources();
916 			schedule();
917 		}
918 		finish_wait(&wakeup_count_wait_queue, &wait);
919 	}
920 
921 	split_counters(&cnt, &inpr);
922 	*count = cnt;
923 	return !inpr;
924 }
925 
926 /**
927  * pm_save_wakeup_count - Save the current number of registered wakeup events.
928  * @count: Value to compare with the current number of registered wakeup events.
929  *
930  * If @count is equal to the current number of registered wakeup events and the
931  * current number of wakeup events being processed is zero, store @count as the
932  * old number of registered wakeup events for pm_check_wakeup_events(), enable
933  * wakeup events detection and return 'true'.  Otherwise disable wakeup events
934  * detection and return 'false'.
935  */
936 bool pm_save_wakeup_count(unsigned int count)
937 {
938 	unsigned int cnt, inpr;
939 	unsigned long flags;
940 
941 	events_check_enabled = false;
942 	spin_lock_irqsave(&events_lock, flags);
943 	split_counters(&cnt, &inpr);
944 	if (cnt == count && inpr == 0) {
945 		saved_count = count;
946 		events_check_enabled = true;
947 	}
948 	spin_unlock_irqrestore(&events_lock, flags);
949 	return events_check_enabled;
950 }
951 
952 #ifdef CONFIG_PM_AUTOSLEEP
953 /**
954  * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
955  * @enabled: Whether to set or to clear the autosleep_enabled flags.
956  */
957 void pm_wakep_autosleep_enabled(bool set)
958 {
959 	struct wakeup_source *ws;
960 	ktime_t now = ktime_get();
961 	int srcuidx;
962 
963 	srcuidx = srcu_read_lock(&wakeup_srcu);
964 	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
965 		spin_lock_irq(&ws->lock);
966 		if (ws->autosleep_enabled != set) {
967 			ws->autosleep_enabled = set;
968 			if (ws->active) {
969 				if (set)
970 					ws->start_prevent_time = now;
971 				else
972 					update_prevent_sleep_time(ws, now);
973 			}
974 		}
975 		spin_unlock_irq(&ws->lock);
976 	}
977 	srcu_read_unlock(&wakeup_srcu, srcuidx);
978 }
979 #endif /* CONFIG_PM_AUTOSLEEP */
980 
981 static struct dentry *wakeup_sources_stats_dentry;
982 
983 /**
984  * print_wakeup_source_stats - Print wakeup source statistics information.
985  * @m: seq_file to print the statistics into.
986  * @ws: Wakeup source object to print the statistics for.
987  */
988 static int print_wakeup_source_stats(struct seq_file *m,
989 				     struct wakeup_source *ws)
990 {
991 	unsigned long flags;
992 	ktime_t total_time;
993 	ktime_t max_time;
994 	unsigned long active_count;
995 	ktime_t active_time;
996 	ktime_t prevent_sleep_time;
997 
998 	spin_lock_irqsave(&ws->lock, flags);
999 
1000 	total_time = ws->total_time;
1001 	max_time = ws->max_time;
1002 	prevent_sleep_time = ws->prevent_sleep_time;
1003 	active_count = ws->active_count;
1004 	if (ws->active) {
1005 		ktime_t now = ktime_get();
1006 
1007 		active_time = ktime_sub(now, ws->last_time);
1008 		total_time = ktime_add(total_time, active_time);
1009 		if (active_time > max_time)
1010 			max_time = active_time;
1011 
1012 		if (ws->autosleep_enabled)
1013 			prevent_sleep_time = ktime_add(prevent_sleep_time,
1014 				ktime_sub(now, ws->start_prevent_time));
1015 	} else {
1016 		active_time = 0;
1017 	}
1018 
1019 	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",
1020 		   ws->name, active_count, ws->event_count,
1021 		   ws->wakeup_count, ws->expire_count,
1022 		   ktime_to_ms(active_time), ktime_to_ms(total_time),
1023 		   ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
1024 		   ktime_to_ms(prevent_sleep_time));
1025 
1026 	spin_unlock_irqrestore(&ws->lock, flags);
1027 
1028 	return 0;
1029 }
1030 
1031 /**
1032  * wakeup_sources_stats_show - Print wakeup sources statistics information.
1033  * @m: seq_file to print the statistics into.
1034  */
1035 static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
1036 {
1037 	struct wakeup_source *ws;
1038 	int srcuidx;
1039 
1040 	seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
1041 		"expire_count\tactive_since\ttotal_time\tmax_time\t"
1042 		"last_change\tprevent_suspend_time\n");
1043 
1044 	srcuidx = srcu_read_lock(&wakeup_srcu);
1045 	list_for_each_entry_rcu(ws, &wakeup_sources, entry)
1046 		print_wakeup_source_stats(m, ws);
1047 	srcu_read_unlock(&wakeup_srcu, srcuidx);
1048 
1049 	print_wakeup_source_stats(m, &deleted_ws);
1050 
1051 	return 0;
1052 }
1053 
1054 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
1055 {
1056 	return single_open(file, wakeup_sources_stats_show, NULL);
1057 }
1058 
1059 static const struct file_operations wakeup_sources_stats_fops = {
1060 	.owner = THIS_MODULE,
1061 	.open = wakeup_sources_stats_open,
1062 	.read = seq_read,
1063 	.llseek = seq_lseek,
1064 	.release = single_release,
1065 };
1066 
1067 static int __init wakeup_sources_debugfs_init(void)
1068 {
1069 	wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
1070 			S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
1071 	return 0;
1072 }
1073 
1074 postcore_initcall(wakeup_sources_debugfs_init);
1075