xref: /openbmc/linux/drivers/base/power/wakeup.c (revision c02b872a)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * drivers/base/power/wakeup.c - System wakeup events framework
4  *
5  * Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
6  */
7 #define pr_fmt(fmt) "PM: " fmt
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 #ifndef CONFIG_SUSPEND
23 suspend_state_t pm_suspend_target_state;
24 #define pm_suspend_target_state	(PM_SUSPEND_ON)
25 #endif
26 
27 #define list_for_each_entry_rcu_locked(pos, head, member) \
28 	list_for_each_entry_rcu(pos, head, member, \
29 		srcu_read_lock_held(&wakeup_srcu))
30 /*
31  * If set, the suspend/hibernate code will abort transitions to a sleep state
32  * if wakeup events are registered during or immediately before the transition.
33  */
34 bool events_check_enabled __read_mostly;
35 
36 /* First wakeup IRQ seen by the kernel in the last cycle. */
37 static unsigned int wakeup_irq[2] __read_mostly;
38 static DEFINE_RAW_SPINLOCK(wakeup_irq_lock);
39 
40 /* If greater than 0 and the system is suspending, terminate the suspend. */
41 static atomic_t pm_abort_suspend __read_mostly;
42 
43 /*
44  * Combined counters of registered wakeup events and wakeup events in progress.
45  * They need to be modified together atomically, so it's better to use one
46  * atomic variable to hold them both.
47  */
48 static atomic_t combined_event_count = ATOMIC_INIT(0);
49 
50 #define IN_PROGRESS_BITS	(sizeof(int) * 4)
51 #define MAX_IN_PROGRESS		((1 << IN_PROGRESS_BITS) - 1)
52 
53 static void split_counters(unsigned int *cnt, unsigned int *inpr)
54 {
55 	unsigned int comb = atomic_read(&combined_event_count);
56 
57 	*cnt = (comb >> IN_PROGRESS_BITS);
58 	*inpr = comb & MAX_IN_PROGRESS;
59 }
60 
61 /* A preserved old value of the events counter. */
62 static unsigned int saved_count;
63 
64 static DEFINE_RAW_SPINLOCK(events_lock);
65 
66 static void pm_wakeup_timer_fn(struct timer_list *t);
67 
68 static LIST_HEAD(wakeup_sources);
69 
70 static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
71 
72 DEFINE_STATIC_SRCU(wakeup_srcu);
73 
74 static struct wakeup_source deleted_ws = {
75 	.name = "deleted",
76 	.lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
77 };
78 
79 static DEFINE_IDA(wakeup_ida);
80 
81 /**
82  * wakeup_source_create - Create a struct wakeup_source object.
83  * @name: Name of the new wakeup source.
84  */
85 struct wakeup_source *wakeup_source_create(const char *name)
86 {
87 	struct wakeup_source *ws;
88 	const char *ws_name;
89 	int id;
90 
91 	ws = kzalloc(sizeof(*ws), GFP_KERNEL);
92 	if (!ws)
93 		goto err_ws;
94 
95 	ws_name = kstrdup_const(name, GFP_KERNEL);
96 	if (!ws_name)
97 		goto err_name;
98 	ws->name = ws_name;
99 
100 	id = ida_alloc(&wakeup_ida, GFP_KERNEL);
101 	if (id < 0)
102 		goto err_id;
103 	ws->id = id;
104 
105 	return ws;
106 
107 err_id:
108 	kfree_const(ws->name);
109 err_name:
110 	kfree(ws);
111 err_ws:
112 	return NULL;
113 }
114 EXPORT_SYMBOL_GPL(wakeup_source_create);
115 
116 /*
117  * Record wakeup_source statistics being deleted into a dummy wakeup_source.
118  */
119 static void wakeup_source_record(struct wakeup_source *ws)
120 {
121 	unsigned long flags;
122 
123 	spin_lock_irqsave(&deleted_ws.lock, flags);
124 
125 	if (ws->event_count) {
126 		deleted_ws.total_time =
127 			ktime_add(deleted_ws.total_time, ws->total_time);
128 		deleted_ws.prevent_sleep_time =
129 			ktime_add(deleted_ws.prevent_sleep_time,
130 				  ws->prevent_sleep_time);
131 		deleted_ws.max_time =
132 			ktime_compare(deleted_ws.max_time, ws->max_time) > 0 ?
133 				deleted_ws.max_time : ws->max_time;
134 		deleted_ws.event_count += ws->event_count;
135 		deleted_ws.active_count += ws->active_count;
136 		deleted_ws.relax_count += ws->relax_count;
137 		deleted_ws.expire_count += ws->expire_count;
138 		deleted_ws.wakeup_count += ws->wakeup_count;
139 	}
140 
141 	spin_unlock_irqrestore(&deleted_ws.lock, flags);
142 }
143 
144 static void wakeup_source_free(struct wakeup_source *ws)
145 {
146 	ida_free(&wakeup_ida, ws->id);
147 	kfree_const(ws->name);
148 	kfree(ws);
149 }
150 
151 /**
152  * wakeup_source_destroy - Destroy a struct wakeup_source object.
153  * @ws: Wakeup source to destroy.
154  *
155  * Use only for wakeup source objects created with wakeup_source_create().
156  */
157 void wakeup_source_destroy(struct wakeup_source *ws)
158 {
159 	if (!ws)
160 		return;
161 
162 	__pm_relax(ws);
163 	wakeup_source_record(ws);
164 	wakeup_source_free(ws);
165 }
166 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
167 
168 /**
169  * wakeup_source_add - Add given object to the list of wakeup sources.
170  * @ws: Wakeup source object to add to the list.
171  */
172 void wakeup_source_add(struct wakeup_source *ws)
173 {
174 	unsigned long flags;
175 
176 	if (WARN_ON(!ws))
177 		return;
178 
179 	spin_lock_init(&ws->lock);
180 	timer_setup(&ws->timer, pm_wakeup_timer_fn, 0);
181 	ws->active = false;
182 
183 	raw_spin_lock_irqsave(&events_lock, flags);
184 	list_add_rcu(&ws->entry, &wakeup_sources);
185 	raw_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 	raw_spin_lock_irqsave(&events_lock, flags);
201 	list_del_rcu(&ws->entry);
202 	raw_spin_unlock_irqrestore(&events_lock, flags);
203 	synchronize_srcu(&wakeup_srcu);
204 
205 	del_timer_sync(&ws->timer);
206 	/*
207 	 * Clear timer.function to make wakeup_source_not_registered() treat
208 	 * this wakeup source as not registered.
209 	 */
210 	ws->timer.function = NULL;
211 }
212 EXPORT_SYMBOL_GPL(wakeup_source_remove);
213 
214 /**
215  * wakeup_source_register - Create wakeup source and add it to the list.
216  * @dev: Device this wakeup source is associated with (or NULL if virtual).
217  * @name: Name of the wakeup source to register.
218  */
219 struct wakeup_source *wakeup_source_register(struct device *dev,
220 					     const char *name)
221 {
222 	struct wakeup_source *ws;
223 	int ret;
224 
225 	ws = wakeup_source_create(name);
226 	if (ws) {
227 		if (!dev || device_is_registered(dev)) {
228 			ret = wakeup_source_sysfs_add(dev, ws);
229 			if (ret) {
230 				wakeup_source_free(ws);
231 				return NULL;
232 			}
233 		}
234 		wakeup_source_add(ws);
235 	}
236 	return ws;
237 }
238 EXPORT_SYMBOL_GPL(wakeup_source_register);
239 
240 /**
241  * wakeup_source_unregister - Remove wakeup source from the list and remove it.
242  * @ws: Wakeup source object to unregister.
243  */
244 void wakeup_source_unregister(struct wakeup_source *ws)
245 {
246 	if (ws) {
247 		wakeup_source_remove(ws);
248 		if (ws->dev)
249 			wakeup_source_sysfs_remove(ws);
250 
251 		wakeup_source_destroy(ws);
252 	}
253 }
254 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
255 
256 /**
257  * wakeup_sources_read_lock - Lock wakeup source list for read.
258  *
259  * Returns an index of srcu lock for struct wakeup_srcu.
260  * This index must be passed to the matching wakeup_sources_read_unlock().
261  */
262 int wakeup_sources_read_lock(void)
263 {
264 	return srcu_read_lock(&wakeup_srcu);
265 }
266 EXPORT_SYMBOL_GPL(wakeup_sources_read_lock);
267 
268 /**
269  * wakeup_sources_read_unlock - Unlock wakeup source list.
270  * @idx: return value from corresponding wakeup_sources_read_lock()
271  */
272 void wakeup_sources_read_unlock(int idx)
273 {
274 	srcu_read_unlock(&wakeup_srcu, idx);
275 }
276 EXPORT_SYMBOL_GPL(wakeup_sources_read_unlock);
277 
278 /**
279  * wakeup_sources_walk_start - Begin a walk on wakeup source list
280  *
281  * Returns first object of the list of wakeup sources.
282  *
283  * Note that to be safe, wakeup sources list needs to be locked by calling
284  * wakeup_source_read_lock() for this.
285  */
286 struct wakeup_source *wakeup_sources_walk_start(void)
287 {
288 	struct list_head *ws_head = &wakeup_sources;
289 
290 	return list_entry_rcu(ws_head->next, struct wakeup_source, entry);
291 }
292 EXPORT_SYMBOL_GPL(wakeup_sources_walk_start);
293 
294 /**
295  * wakeup_sources_walk_next - Get next wakeup source from the list
296  * @ws: Previous wakeup source object
297  *
298  * Note that to be safe, wakeup sources list needs to be locked by calling
299  * wakeup_source_read_lock() for this.
300  */
301 struct wakeup_source *wakeup_sources_walk_next(struct wakeup_source *ws)
302 {
303 	struct list_head *ws_head = &wakeup_sources;
304 
305 	return list_next_or_null_rcu(ws_head, &ws->entry,
306 				struct wakeup_source, entry);
307 }
308 EXPORT_SYMBOL_GPL(wakeup_sources_walk_next);
309 
310 /**
311  * device_wakeup_attach - Attach a wakeup source object to a device object.
312  * @dev: Device to handle.
313  * @ws: Wakeup source object to attach to @dev.
314  *
315  * This causes @dev to be treated as a wakeup device.
316  */
317 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
318 {
319 	spin_lock_irq(&dev->power.lock);
320 	if (dev->power.wakeup) {
321 		spin_unlock_irq(&dev->power.lock);
322 		return -EEXIST;
323 	}
324 	dev->power.wakeup = ws;
325 	if (dev->power.wakeirq)
326 		device_wakeup_attach_irq(dev, dev->power.wakeirq);
327 	spin_unlock_irq(&dev->power.lock);
328 	return 0;
329 }
330 
331 /**
332  * device_wakeup_enable - Enable given device to be a wakeup source.
333  * @dev: Device to handle.
334  *
335  * Create a wakeup source object, register it and attach it to @dev.
336  */
337 int device_wakeup_enable(struct device *dev)
338 {
339 	struct wakeup_source *ws;
340 	int ret;
341 
342 	if (!dev || !dev->power.can_wakeup)
343 		return -EINVAL;
344 
345 	if (pm_suspend_target_state != PM_SUSPEND_ON)
346 		dev_dbg(dev, "Suspicious %s() during system transition!\n", __func__);
347 
348 	ws = wakeup_source_register(dev, dev_name(dev));
349 	if (!ws)
350 		return -ENOMEM;
351 
352 	ret = device_wakeup_attach(dev, ws);
353 	if (ret)
354 		wakeup_source_unregister(ws);
355 
356 	return ret;
357 }
358 EXPORT_SYMBOL_GPL(device_wakeup_enable);
359 
360 /**
361  * device_wakeup_attach_irq - Attach a wakeirq to a wakeup source
362  * @dev: Device to handle
363  * @wakeirq: Device specific wakeirq entry
364  *
365  * Attach a device wakeirq to the wakeup source so the device
366  * wake IRQ can be configured automatically for suspend and
367  * resume.
368  *
369  * Call under the device's power.lock lock.
370  */
371 void device_wakeup_attach_irq(struct device *dev,
372 			     struct wake_irq *wakeirq)
373 {
374 	struct wakeup_source *ws;
375 
376 	ws = dev->power.wakeup;
377 	if (!ws)
378 		return;
379 
380 	if (ws->wakeirq)
381 		dev_err(dev, "Leftover wakeup IRQ found, overriding\n");
382 
383 	ws->wakeirq = wakeirq;
384 }
385 
386 /**
387  * device_wakeup_detach_irq - Detach a wakeirq from a wakeup source
388  * @dev: Device to handle
389  *
390  * Removes a device wakeirq from the wakeup source.
391  *
392  * Call under the device's power.lock lock.
393  */
394 void device_wakeup_detach_irq(struct device *dev)
395 {
396 	struct wakeup_source *ws;
397 
398 	ws = dev->power.wakeup;
399 	if (ws)
400 		ws->wakeirq = NULL;
401 }
402 
403 /**
404  * device_wakeup_arm_wake_irqs -
405  *
406  * Iterates over the list of device wakeirqs to arm them.
407  */
408 void device_wakeup_arm_wake_irqs(void)
409 {
410 	struct wakeup_source *ws;
411 	int srcuidx;
412 
413 	srcuidx = srcu_read_lock(&wakeup_srcu);
414 	list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry)
415 		dev_pm_arm_wake_irq(ws->wakeirq);
416 	srcu_read_unlock(&wakeup_srcu, srcuidx);
417 }
418 
419 /**
420  * device_wakeup_disarm_wake_irqs -
421  *
422  * Iterates over the list of device wakeirqs to disarm them.
423  */
424 void device_wakeup_disarm_wake_irqs(void)
425 {
426 	struct wakeup_source *ws;
427 	int srcuidx;
428 
429 	srcuidx = srcu_read_lock(&wakeup_srcu);
430 	list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry)
431 		dev_pm_disarm_wake_irq(ws->wakeirq);
432 	srcu_read_unlock(&wakeup_srcu, srcuidx);
433 }
434 
435 /**
436  * device_wakeup_detach - Detach a device's wakeup source object from it.
437  * @dev: Device to detach the wakeup source object from.
438  *
439  * After it returns, @dev will not be treated as a wakeup device any more.
440  */
441 static struct wakeup_source *device_wakeup_detach(struct device *dev)
442 {
443 	struct wakeup_source *ws;
444 
445 	spin_lock_irq(&dev->power.lock);
446 	ws = dev->power.wakeup;
447 	dev->power.wakeup = NULL;
448 	spin_unlock_irq(&dev->power.lock);
449 	return ws;
450 }
451 
452 /**
453  * device_wakeup_disable - Do not regard a device as a wakeup source any more.
454  * @dev: Device to handle.
455  *
456  * Detach the @dev's wakeup source object from it, unregister this wakeup source
457  * object and destroy it.
458  */
459 int device_wakeup_disable(struct device *dev)
460 {
461 	struct wakeup_source *ws;
462 
463 	if (!dev || !dev->power.can_wakeup)
464 		return -EINVAL;
465 
466 	ws = device_wakeup_detach(dev);
467 	wakeup_source_unregister(ws);
468 	return 0;
469 }
470 EXPORT_SYMBOL_GPL(device_wakeup_disable);
471 
472 /**
473  * device_set_wakeup_capable - Set/reset device wakeup capability flag.
474  * @dev: Device to handle.
475  * @capable: Whether or not @dev is capable of waking up the system from sleep.
476  *
477  * If @capable is set, set the @dev's power.can_wakeup flag and add its
478  * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
479  * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
480  *
481  * This function may sleep and it can't be called from any context where
482  * sleeping is not allowed.
483  */
484 void device_set_wakeup_capable(struct device *dev, bool capable)
485 {
486 	if (!!dev->power.can_wakeup == !!capable)
487 		return;
488 
489 	dev->power.can_wakeup = capable;
490 	if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
491 		if (capable) {
492 			int ret = wakeup_sysfs_add(dev);
493 
494 			if (ret)
495 				dev_info(dev, "Wakeup sysfs attributes not added\n");
496 		} else {
497 			wakeup_sysfs_remove(dev);
498 		}
499 	}
500 }
501 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
502 
503 /**
504  * device_init_wakeup - Device wakeup initialization.
505  * @dev: Device to handle.
506  * @enable: Whether or not to enable @dev as a wakeup device.
507  *
508  * By default, most devices should leave wakeup disabled.  The exceptions are
509  * devices that everyone expects to be wakeup sources: keyboards, power buttons,
510  * possibly network interfaces, etc.  Also, devices that don't generate their
511  * own wakeup requests but merely forward requests from one bus to another
512  * (like PCI bridges) should have wakeup enabled by default.
513  */
514 int device_init_wakeup(struct device *dev, bool enable)
515 {
516 	int ret = 0;
517 
518 	if (!dev)
519 		return -EINVAL;
520 
521 	if (enable) {
522 		device_set_wakeup_capable(dev, true);
523 		ret = device_wakeup_enable(dev);
524 	} else {
525 		device_wakeup_disable(dev);
526 		device_set_wakeup_capable(dev, false);
527 	}
528 
529 	return ret;
530 }
531 EXPORT_SYMBOL_GPL(device_init_wakeup);
532 
533 /**
534  * device_set_wakeup_enable - Enable or disable a device to wake up the system.
535  * @dev: Device to handle.
536  * @enable: enable/disable flag
537  */
538 int device_set_wakeup_enable(struct device *dev, bool enable)
539 {
540 	return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
541 }
542 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
543 
544 /**
545  * wakeup_source_not_registered - validate the given wakeup source.
546  * @ws: Wakeup source to be validated.
547  */
548 static bool wakeup_source_not_registered(struct wakeup_source *ws)
549 {
550 	/*
551 	 * Use timer struct to check if the given source is initialized
552 	 * by wakeup_source_add.
553 	 */
554 	return ws->timer.function != pm_wakeup_timer_fn;
555 }
556 
557 /*
558  * The functions below use the observation that each wakeup event starts a
559  * period in which the system should not be suspended.  The moment this period
560  * will end depends on how the wakeup event is going to be processed after being
561  * detected and all of the possible cases can be divided into two distinct
562  * groups.
563  *
564  * First, a wakeup event may be detected by the same functional unit that will
565  * carry out the entire processing of it and possibly will pass it to user space
566  * for further processing.  In that case the functional unit that has detected
567  * the event may later "close" the "no suspend" period associated with it
568  * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
569  * pm_relax(), balanced with each other, is supposed to be used in such
570  * situations.
571  *
572  * Second, a wakeup event may be detected by one functional unit and processed
573  * by another one.  In that case the unit that has detected it cannot really
574  * "close" the "no suspend" period associated with it, unless it knows in
575  * advance what's going to happen to the event during processing.  This
576  * knowledge, however, may not be available to it, so it can simply specify time
577  * to wait before the system can be suspended and pass it as the second
578  * argument of pm_wakeup_event().
579  *
580  * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
581  * "no suspend" period will be ended either by the pm_relax(), or by the timer
582  * function executed when the timer expires, whichever comes first.
583  */
584 
585 /**
586  * wakeup_source_activate - Mark given wakeup source as active.
587  * @ws: Wakeup source to handle.
588  *
589  * Update the @ws' statistics and, if @ws has just been activated, notify the PM
590  * core of the event by incrementing the counter of the wakeup events being
591  * processed.
592  */
593 static void wakeup_source_activate(struct wakeup_source *ws)
594 {
595 	unsigned int cec;
596 
597 	if (WARN_ONCE(wakeup_source_not_registered(ws),
598 			"unregistered wakeup source\n"))
599 		return;
600 
601 	ws->active = true;
602 	ws->active_count++;
603 	ws->last_time = ktime_get();
604 	if (ws->autosleep_enabled)
605 		ws->start_prevent_time = ws->last_time;
606 
607 	/* Increment the counter of events in progress. */
608 	cec = atomic_inc_return(&combined_event_count);
609 
610 	trace_wakeup_source_activate(ws->name, cec);
611 }
612 
613 /**
614  * wakeup_source_report_event - Report wakeup event using the given source.
615  * @ws: Wakeup source to report the event for.
616  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
617  */
618 static void wakeup_source_report_event(struct wakeup_source *ws, bool hard)
619 {
620 	ws->event_count++;
621 	/* This is racy, but the counter is approximate anyway. */
622 	if (events_check_enabled)
623 		ws->wakeup_count++;
624 
625 	if (!ws->active)
626 		wakeup_source_activate(ws);
627 
628 	if (hard)
629 		pm_system_wakeup();
630 }
631 
632 /**
633  * __pm_stay_awake - Notify the PM core of a wakeup event.
634  * @ws: Wakeup source object associated with the source of the event.
635  *
636  * It is safe to call this function from interrupt context.
637  */
638 void __pm_stay_awake(struct wakeup_source *ws)
639 {
640 	unsigned long flags;
641 
642 	if (!ws)
643 		return;
644 
645 	spin_lock_irqsave(&ws->lock, flags);
646 
647 	wakeup_source_report_event(ws, false);
648 	del_timer(&ws->timer);
649 	ws->timer_expires = 0;
650 
651 	spin_unlock_irqrestore(&ws->lock, flags);
652 }
653 EXPORT_SYMBOL_GPL(__pm_stay_awake);
654 
655 /**
656  * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
657  * @dev: Device the wakeup event is related to.
658  *
659  * Notify the PM core of a wakeup event (signaled by @dev) by calling
660  * __pm_stay_awake for the @dev's wakeup source object.
661  *
662  * Call this function after detecting of a wakeup event if pm_relax() is going
663  * to be called directly after processing the event (and possibly passing it to
664  * user space for further processing).
665  */
666 void pm_stay_awake(struct device *dev)
667 {
668 	unsigned long flags;
669 
670 	if (!dev)
671 		return;
672 
673 	spin_lock_irqsave(&dev->power.lock, flags);
674 	__pm_stay_awake(dev->power.wakeup);
675 	spin_unlock_irqrestore(&dev->power.lock, flags);
676 }
677 EXPORT_SYMBOL_GPL(pm_stay_awake);
678 
679 #ifdef CONFIG_PM_AUTOSLEEP
680 static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
681 {
682 	ktime_t delta = ktime_sub(now, ws->start_prevent_time);
683 	ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
684 }
685 #else
686 static inline void update_prevent_sleep_time(struct wakeup_source *ws,
687 					     ktime_t now) {}
688 #endif
689 
690 /**
691  * wakeup_source_deactivate - Mark given wakeup source as inactive.
692  * @ws: Wakeup source to handle.
693  *
694  * Update the @ws' statistics and notify the PM core that the wakeup source has
695  * become inactive by decrementing the counter of wakeup events being processed
696  * and incrementing the counter of registered wakeup events.
697  */
698 static void wakeup_source_deactivate(struct wakeup_source *ws)
699 {
700 	unsigned int cnt, inpr, cec;
701 	ktime_t duration;
702 	ktime_t now;
703 
704 	ws->relax_count++;
705 	/*
706 	 * __pm_relax() may be called directly or from a timer function.
707 	 * If it is called directly right after the timer function has been
708 	 * started, but before the timer function calls __pm_relax(), it is
709 	 * possible that __pm_stay_awake() will be called in the meantime and
710 	 * will set ws->active.  Then, ws->active may be cleared immediately
711 	 * by the __pm_relax() called from the timer function, but in such a
712 	 * case ws->relax_count will be different from ws->active_count.
713 	 */
714 	if (ws->relax_count != ws->active_count) {
715 		ws->relax_count--;
716 		return;
717 	}
718 
719 	ws->active = false;
720 
721 	now = ktime_get();
722 	duration = ktime_sub(now, ws->last_time);
723 	ws->total_time = ktime_add(ws->total_time, duration);
724 	if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
725 		ws->max_time = duration;
726 
727 	ws->last_time = now;
728 	del_timer(&ws->timer);
729 	ws->timer_expires = 0;
730 
731 	if (ws->autosleep_enabled)
732 		update_prevent_sleep_time(ws, now);
733 
734 	/*
735 	 * Increment the counter of registered wakeup events and decrement the
736 	 * counter of wakeup events in progress simultaneously.
737 	 */
738 	cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
739 	trace_wakeup_source_deactivate(ws->name, cec);
740 
741 	split_counters(&cnt, &inpr);
742 	if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
743 		wake_up(&wakeup_count_wait_queue);
744 }
745 
746 /**
747  * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
748  * @ws: Wakeup source object associated with the source of the event.
749  *
750  * Call this function for wakeup events whose processing started with calling
751  * __pm_stay_awake().
752  *
753  * It is safe to call it from interrupt context.
754  */
755 void __pm_relax(struct wakeup_source *ws)
756 {
757 	unsigned long flags;
758 
759 	if (!ws)
760 		return;
761 
762 	spin_lock_irqsave(&ws->lock, flags);
763 	if (ws->active)
764 		wakeup_source_deactivate(ws);
765 	spin_unlock_irqrestore(&ws->lock, flags);
766 }
767 EXPORT_SYMBOL_GPL(__pm_relax);
768 
769 /**
770  * pm_relax - Notify the PM core that processing of a wakeup event has ended.
771  * @dev: Device that signaled the event.
772  *
773  * Execute __pm_relax() for the @dev's wakeup source object.
774  */
775 void pm_relax(struct device *dev)
776 {
777 	unsigned long flags;
778 
779 	if (!dev)
780 		return;
781 
782 	spin_lock_irqsave(&dev->power.lock, flags);
783 	__pm_relax(dev->power.wakeup);
784 	spin_unlock_irqrestore(&dev->power.lock, flags);
785 }
786 EXPORT_SYMBOL_GPL(pm_relax);
787 
788 /**
789  * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
790  * @t: timer list
791  *
792  * Call wakeup_source_deactivate() for the wakeup source whose address is stored
793  * in @data if it is currently active and its timer has not been canceled and
794  * the expiration time of the timer is not in future.
795  */
796 static void pm_wakeup_timer_fn(struct timer_list *t)
797 {
798 	struct wakeup_source *ws = from_timer(ws, t, timer);
799 	unsigned long flags;
800 
801 	spin_lock_irqsave(&ws->lock, flags);
802 
803 	if (ws->active && ws->timer_expires
804 	    && time_after_eq(jiffies, ws->timer_expires)) {
805 		wakeup_source_deactivate(ws);
806 		ws->expire_count++;
807 	}
808 
809 	spin_unlock_irqrestore(&ws->lock, flags);
810 }
811 
812 /**
813  * pm_wakeup_ws_event - Notify the PM core of a wakeup event.
814  * @ws: Wakeup source object associated with the event source.
815  * @msec: Anticipated event processing time (in milliseconds).
816  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
817  *
818  * Notify the PM core of a wakeup event whose source is @ws that will take
819  * approximately @msec milliseconds to be processed by the kernel.  If @ws is
820  * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
821  * execute pm_wakeup_timer_fn() in future.
822  *
823  * It is safe to call this function from interrupt context.
824  */
825 void pm_wakeup_ws_event(struct wakeup_source *ws, unsigned int msec, bool hard)
826 {
827 	unsigned long flags;
828 	unsigned long expires;
829 
830 	if (!ws)
831 		return;
832 
833 	spin_lock_irqsave(&ws->lock, flags);
834 
835 	wakeup_source_report_event(ws, hard);
836 
837 	if (!msec) {
838 		wakeup_source_deactivate(ws);
839 		goto unlock;
840 	}
841 
842 	expires = jiffies + msecs_to_jiffies(msec);
843 	if (!expires)
844 		expires = 1;
845 
846 	if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
847 		mod_timer(&ws->timer, expires);
848 		ws->timer_expires = expires;
849 	}
850 
851  unlock:
852 	spin_unlock_irqrestore(&ws->lock, flags);
853 }
854 EXPORT_SYMBOL_GPL(pm_wakeup_ws_event);
855 
856 /**
857  * pm_wakeup_dev_event - Notify the PM core of a wakeup event.
858  * @dev: Device the wakeup event is related to.
859  * @msec: Anticipated event processing time (in milliseconds).
860  * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
861  *
862  * Call pm_wakeup_ws_event() for the @dev's wakeup source object.
863  */
864 void pm_wakeup_dev_event(struct device *dev, unsigned int msec, bool hard)
865 {
866 	unsigned long flags;
867 
868 	if (!dev)
869 		return;
870 
871 	spin_lock_irqsave(&dev->power.lock, flags);
872 	pm_wakeup_ws_event(dev->power.wakeup, msec, hard);
873 	spin_unlock_irqrestore(&dev->power.lock, flags);
874 }
875 EXPORT_SYMBOL_GPL(pm_wakeup_dev_event);
876 
877 void pm_print_active_wakeup_sources(void)
878 {
879 	struct wakeup_source *ws;
880 	int srcuidx, active = 0;
881 	struct wakeup_source *last_activity_ws = NULL;
882 
883 	srcuidx = srcu_read_lock(&wakeup_srcu);
884 	list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
885 		if (ws->active) {
886 			pm_pr_dbg("active wakeup source: %s\n", ws->name);
887 			active = 1;
888 		} else if (!active &&
889 			   (!last_activity_ws ||
890 			    ktime_to_ns(ws->last_time) >
891 			    ktime_to_ns(last_activity_ws->last_time))) {
892 			last_activity_ws = ws;
893 		}
894 	}
895 
896 	if (!active && last_activity_ws)
897 		pm_pr_dbg("last active wakeup source: %s\n",
898 			last_activity_ws->name);
899 	srcu_read_unlock(&wakeup_srcu, srcuidx);
900 }
901 EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);
902 
903 /**
904  * pm_wakeup_pending - Check if power transition in progress should be aborted.
905  *
906  * Compare the current number of registered wakeup events with its preserved
907  * value from the past and return true if new wakeup events have been registered
908  * since the old value was stored.  Also return true if the current number of
909  * wakeup events being processed is different from zero.
910  */
911 bool pm_wakeup_pending(void)
912 {
913 	unsigned long flags;
914 	bool ret = false;
915 
916 	raw_spin_lock_irqsave(&events_lock, flags);
917 	if (events_check_enabled) {
918 		unsigned int cnt, inpr;
919 
920 		split_counters(&cnt, &inpr);
921 		ret = (cnt != saved_count || inpr > 0);
922 		events_check_enabled = !ret;
923 	}
924 	raw_spin_unlock_irqrestore(&events_lock, flags);
925 
926 	if (ret) {
927 		pm_pr_dbg("Wakeup pending, aborting suspend\n");
928 		pm_print_active_wakeup_sources();
929 	}
930 
931 	return ret || atomic_read(&pm_abort_suspend) > 0;
932 }
933 EXPORT_SYMBOL_GPL(pm_wakeup_pending);
934 
935 void pm_system_wakeup(void)
936 {
937 	atomic_inc(&pm_abort_suspend);
938 	s2idle_wake();
939 }
940 EXPORT_SYMBOL_GPL(pm_system_wakeup);
941 
942 void pm_system_cancel_wakeup(void)
943 {
944 	atomic_dec_if_positive(&pm_abort_suspend);
945 }
946 
947 void pm_wakeup_clear(unsigned int irq_number)
948 {
949 	raw_spin_lock_irq(&wakeup_irq_lock);
950 
951 	if (irq_number && wakeup_irq[0] == irq_number)
952 		wakeup_irq[0] = wakeup_irq[1];
953 	else
954 		wakeup_irq[0] = 0;
955 
956 	wakeup_irq[1] = 0;
957 
958 	raw_spin_unlock_irq(&wakeup_irq_lock);
959 
960 	if (!irq_number)
961 		atomic_set(&pm_abort_suspend, 0);
962 }
963 
964 void pm_system_irq_wakeup(unsigned int irq_number)
965 {
966 	unsigned long flags;
967 
968 	raw_spin_lock_irqsave(&wakeup_irq_lock, flags);
969 
970 	if (wakeup_irq[0] == 0)
971 		wakeup_irq[0] = irq_number;
972 	else if (wakeup_irq[1] == 0)
973 		wakeup_irq[1] = irq_number;
974 	else
975 		irq_number = 0;
976 
977 	raw_spin_unlock_irqrestore(&wakeup_irq_lock, flags);
978 
979 	if (irq_number)
980 		pm_system_wakeup();
981 }
982 
983 unsigned int pm_wakeup_irq(void)
984 {
985 	return wakeup_irq[0];
986 }
987 
988 /**
989  * pm_get_wakeup_count - Read the number of registered wakeup events.
990  * @count: Address to store the value at.
991  * @block: Whether or not to block.
992  *
993  * Store the number of registered wakeup events at the address in @count.  If
994  * @block is set, block until the current number of wakeup events being
995  * processed is zero.
996  *
997  * Return 'false' if the current number of wakeup events being processed is
998  * nonzero.  Otherwise return 'true'.
999  */
1000 bool pm_get_wakeup_count(unsigned int *count, bool block)
1001 {
1002 	unsigned int cnt, inpr;
1003 
1004 	if (block) {
1005 		DEFINE_WAIT(wait);
1006 
1007 		for (;;) {
1008 			prepare_to_wait(&wakeup_count_wait_queue, &wait,
1009 					TASK_INTERRUPTIBLE);
1010 			split_counters(&cnt, &inpr);
1011 			if (inpr == 0 || signal_pending(current))
1012 				break;
1013 			pm_print_active_wakeup_sources();
1014 			schedule();
1015 		}
1016 		finish_wait(&wakeup_count_wait_queue, &wait);
1017 	}
1018 
1019 	split_counters(&cnt, &inpr);
1020 	*count = cnt;
1021 	return !inpr;
1022 }
1023 
1024 /**
1025  * pm_save_wakeup_count - Save the current number of registered wakeup events.
1026  * @count: Value to compare with the current number of registered wakeup events.
1027  *
1028  * If @count is equal to the current number of registered wakeup events and the
1029  * current number of wakeup events being processed is zero, store @count as the
1030  * old number of registered wakeup events for pm_check_wakeup_events(), enable
1031  * wakeup events detection and return 'true'.  Otherwise disable wakeup events
1032  * detection and return 'false'.
1033  */
1034 bool pm_save_wakeup_count(unsigned int count)
1035 {
1036 	unsigned int cnt, inpr;
1037 	unsigned long flags;
1038 
1039 	events_check_enabled = false;
1040 	raw_spin_lock_irqsave(&events_lock, flags);
1041 	split_counters(&cnt, &inpr);
1042 	if (cnt == count && inpr == 0) {
1043 		saved_count = count;
1044 		events_check_enabled = true;
1045 	}
1046 	raw_spin_unlock_irqrestore(&events_lock, flags);
1047 	return events_check_enabled;
1048 }
1049 
1050 #ifdef CONFIG_PM_AUTOSLEEP
1051 /**
1052  * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
1053  * @set: Whether to set or to clear the autosleep_enabled flags.
1054  */
1055 void pm_wakep_autosleep_enabled(bool set)
1056 {
1057 	struct wakeup_source *ws;
1058 	ktime_t now = ktime_get();
1059 	int srcuidx;
1060 
1061 	srcuidx = srcu_read_lock(&wakeup_srcu);
1062 	list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
1063 		spin_lock_irq(&ws->lock);
1064 		if (ws->autosleep_enabled != set) {
1065 			ws->autosleep_enabled = set;
1066 			if (ws->active) {
1067 				if (set)
1068 					ws->start_prevent_time = now;
1069 				else
1070 					update_prevent_sleep_time(ws, now);
1071 			}
1072 		}
1073 		spin_unlock_irq(&ws->lock);
1074 	}
1075 	srcu_read_unlock(&wakeup_srcu, srcuidx);
1076 }
1077 #endif /* CONFIG_PM_AUTOSLEEP */
1078 
1079 /**
1080  * print_wakeup_source_stats - Print wakeup source statistics information.
1081  * @m: seq_file to print the statistics into.
1082  * @ws: Wakeup source object to print the statistics for.
1083  */
1084 static int print_wakeup_source_stats(struct seq_file *m,
1085 				     struct wakeup_source *ws)
1086 {
1087 	unsigned long flags;
1088 	ktime_t total_time;
1089 	ktime_t max_time;
1090 	unsigned long active_count;
1091 	ktime_t active_time;
1092 	ktime_t prevent_sleep_time;
1093 
1094 	spin_lock_irqsave(&ws->lock, flags);
1095 
1096 	total_time = ws->total_time;
1097 	max_time = ws->max_time;
1098 	prevent_sleep_time = ws->prevent_sleep_time;
1099 	active_count = ws->active_count;
1100 	if (ws->active) {
1101 		ktime_t now = ktime_get();
1102 
1103 		active_time = ktime_sub(now, ws->last_time);
1104 		total_time = ktime_add(total_time, active_time);
1105 		if (active_time > max_time)
1106 			max_time = active_time;
1107 
1108 		if (ws->autosleep_enabled)
1109 			prevent_sleep_time = ktime_add(prevent_sleep_time,
1110 				ktime_sub(now, ws->start_prevent_time));
1111 	} else {
1112 		active_time = 0;
1113 	}
1114 
1115 	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",
1116 		   ws->name, active_count, ws->event_count,
1117 		   ws->wakeup_count, ws->expire_count,
1118 		   ktime_to_ms(active_time), ktime_to_ms(total_time),
1119 		   ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
1120 		   ktime_to_ms(prevent_sleep_time));
1121 
1122 	spin_unlock_irqrestore(&ws->lock, flags);
1123 
1124 	return 0;
1125 }
1126 
1127 static void *wakeup_sources_stats_seq_start(struct seq_file *m,
1128 					loff_t *pos)
1129 {
1130 	struct wakeup_source *ws;
1131 	loff_t n = *pos;
1132 	int *srcuidx = m->private;
1133 
1134 	if (n == 0) {
1135 		seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
1136 			"expire_count\tactive_since\ttotal_time\tmax_time\t"
1137 			"last_change\tprevent_suspend_time\n");
1138 	}
1139 
1140 	*srcuidx = srcu_read_lock(&wakeup_srcu);
1141 	list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
1142 		if (n-- <= 0)
1143 			return ws;
1144 	}
1145 
1146 	return NULL;
1147 }
1148 
1149 static void *wakeup_sources_stats_seq_next(struct seq_file *m,
1150 					void *v, loff_t *pos)
1151 {
1152 	struct wakeup_source *ws = v;
1153 	struct wakeup_source *next_ws = NULL;
1154 
1155 	++(*pos);
1156 
1157 	list_for_each_entry_continue_rcu(ws, &wakeup_sources, entry) {
1158 		next_ws = ws;
1159 		break;
1160 	}
1161 
1162 	if (!next_ws)
1163 		print_wakeup_source_stats(m, &deleted_ws);
1164 
1165 	return next_ws;
1166 }
1167 
1168 static void wakeup_sources_stats_seq_stop(struct seq_file *m, void *v)
1169 {
1170 	int *srcuidx = m->private;
1171 
1172 	srcu_read_unlock(&wakeup_srcu, *srcuidx);
1173 }
1174 
1175 /**
1176  * wakeup_sources_stats_seq_show - Print wakeup sources statistics information.
1177  * @m: seq_file to print the statistics into.
1178  * @v: wakeup_source of each iteration
1179  */
1180 static int wakeup_sources_stats_seq_show(struct seq_file *m, void *v)
1181 {
1182 	struct wakeup_source *ws = v;
1183 
1184 	print_wakeup_source_stats(m, ws);
1185 
1186 	return 0;
1187 }
1188 
1189 static const struct seq_operations wakeup_sources_stats_seq_ops = {
1190 	.start = wakeup_sources_stats_seq_start,
1191 	.next  = wakeup_sources_stats_seq_next,
1192 	.stop  = wakeup_sources_stats_seq_stop,
1193 	.show  = wakeup_sources_stats_seq_show,
1194 };
1195 
1196 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
1197 {
1198 	return seq_open_private(file, &wakeup_sources_stats_seq_ops, sizeof(int));
1199 }
1200 
1201 static const struct file_operations wakeup_sources_stats_fops = {
1202 	.owner = THIS_MODULE,
1203 	.open = wakeup_sources_stats_open,
1204 	.read = seq_read,
1205 	.llseek = seq_lseek,
1206 	.release = seq_release_private,
1207 };
1208 
1209 static int __init wakeup_sources_debugfs_init(void)
1210 {
1211 	debugfs_create_file("wakeup_sources", 0444, NULL, NULL,
1212 			    &wakeup_sources_stats_fops);
1213 	return 0;
1214 }
1215 
1216 postcore_initcall(wakeup_sources_debugfs_init);
1217