2 * drivers/base/power/wakeup.c - System wakeup events framework
4 * Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
6 * This file is released under the GPLv2.
9 #include <linux/device.h>
10 #include <linux/slab.h>
11 #include <linux/sched.h>
12 #include <linux/capability.h>
13 #include <linux/suspend.h>
14 #include <linux/seq_file.h>
15 #include <linux/debugfs.h>
22 * If set, the suspend/hibernate code will abort transitions to a sleep state
23 * if wakeup events are registered during or immediately before the transition.
25 bool events_check_enabled;
28 * Combined counters of registered wakeup events and wakeup events in progress.
29 * They need to be modified together atomically, so it's better to use one
30 * atomic variable to hold them both.
32 static atomic_t combined_event_count = ATOMIC_INIT(0);
34 #define IN_PROGRESS_BITS (sizeof(int) * 4)
35 #define MAX_IN_PROGRESS ((1 << IN_PROGRESS_BITS) - 1)
37 static void split_counters(unsigned int *cnt, unsigned int *inpr)
39 unsigned int comb = atomic_read(&combined_event_count);
41 *cnt = (comb >> IN_PROGRESS_BITS);
42 *inpr = comb & MAX_IN_PROGRESS;
45 /* A preserved old value of the events counter. */
46 static unsigned int saved_count;
48 static DEFINE_SPINLOCK(events_lock);
50 static void pm_wakeup_timer_fn(unsigned long data);
52 static LIST_HEAD(wakeup_sources);
55 * wakeup_source_create - Create a struct wakeup_source object.
56 * @name: Name of the new wakeup source.
58 struct wakeup_source *wakeup_source_create(const char *name)
60 struct wakeup_source *ws;
62 ws = kzalloc(sizeof(*ws), GFP_KERNEL);
66 spin_lock_init(&ws->lock);
68 ws->name = kstrdup(name, GFP_KERNEL);
72 EXPORT_SYMBOL_GPL(wakeup_source_create);
75 * wakeup_source_destroy - Destroy a struct wakeup_source object.
76 * @ws: Wakeup source to destroy.
78 void wakeup_source_destroy(struct wakeup_source *ws)
83 spin_lock_irq(&ws->lock);
85 spin_unlock_irq(&ws->lock);
87 schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
89 spin_lock_irq(&ws->lock);
91 spin_unlock_irq(&ws->lock);
96 EXPORT_SYMBOL_GPL(wakeup_source_destroy);
99 * wakeup_source_add - Add given object to the list of wakeup sources.
100 * @ws: Wakeup source object to add to the list.
102 void wakeup_source_add(struct wakeup_source *ws)
107 setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
110 spin_lock_irq(&events_lock);
111 list_add_rcu(&ws->entry, &wakeup_sources);
112 spin_unlock_irq(&events_lock);
114 EXPORT_SYMBOL_GPL(wakeup_source_add);
117 * wakeup_source_remove - Remove given object from the wakeup sources list.
118 * @ws: Wakeup source object to remove from the list.
120 void wakeup_source_remove(struct wakeup_source *ws)
125 spin_lock_irq(&events_lock);
126 list_del_rcu(&ws->entry);
127 spin_unlock_irq(&events_lock);
130 EXPORT_SYMBOL_GPL(wakeup_source_remove);
133 * wakeup_source_register - Create wakeup source and add it to the list.
134 * @name: Name of the wakeup source to register.
136 struct wakeup_source *wakeup_source_register(const char *name)
138 struct wakeup_source *ws;
140 ws = wakeup_source_create(name);
142 wakeup_source_add(ws);
146 EXPORT_SYMBOL_GPL(wakeup_source_register);
149 * wakeup_source_unregister - Remove wakeup source from the list and remove it.
150 * @ws: Wakeup source object to unregister.
152 void wakeup_source_unregister(struct wakeup_source *ws)
154 wakeup_source_remove(ws);
155 wakeup_source_destroy(ws);
157 EXPORT_SYMBOL_GPL(wakeup_source_unregister);
160 * device_wakeup_attach - Attach a wakeup source object to a device object.
161 * @dev: Device to handle.
162 * @ws: Wakeup source object to attach to @dev.
164 * This causes @dev to be treated as a wakeup device.
166 static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
168 spin_lock_irq(&dev->power.lock);
169 if (dev->power.wakeup) {
170 spin_unlock_irq(&dev->power.lock);
173 dev->power.wakeup = ws;
174 spin_unlock_irq(&dev->power.lock);
179 * device_wakeup_enable - Enable given device to be a wakeup source.
180 * @dev: Device to handle.
182 * Create a wakeup source object, register it and attach it to @dev.
184 int device_wakeup_enable(struct device *dev)
186 struct wakeup_source *ws;
189 if (!dev || !dev->power.can_wakeup)
192 ws = wakeup_source_register(dev_name(dev));
196 ret = device_wakeup_attach(dev, ws);
198 wakeup_source_unregister(ws);
202 EXPORT_SYMBOL_GPL(device_wakeup_enable);
205 * device_wakeup_detach - Detach a device's wakeup source object from it.
206 * @dev: Device to detach the wakeup source object from.
208 * After it returns, @dev will not be treated as a wakeup device any more.
210 static struct wakeup_source *device_wakeup_detach(struct device *dev)
212 struct wakeup_source *ws;
214 spin_lock_irq(&dev->power.lock);
215 ws = dev->power.wakeup;
216 dev->power.wakeup = NULL;
217 spin_unlock_irq(&dev->power.lock);
222 * device_wakeup_disable - Do not regard a device as a wakeup source any more.
223 * @dev: Device to handle.
225 * Detach the @dev's wakeup source object from it, unregister this wakeup source
226 * object and destroy it.
228 int device_wakeup_disable(struct device *dev)
230 struct wakeup_source *ws;
232 if (!dev || !dev->power.can_wakeup)
235 ws = device_wakeup_detach(dev);
237 wakeup_source_unregister(ws);
241 EXPORT_SYMBOL_GPL(device_wakeup_disable);
244 * device_set_wakeup_capable - Set/reset device wakeup capability flag.
245 * @dev: Device to handle.
246 * @capable: Whether or not @dev is capable of waking up the system from sleep.
248 * If @capable is set, set the @dev's power.can_wakeup flag and add its
249 * wakeup-related attributes to sysfs. Otherwise, unset the @dev's
250 * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
252 * This function may sleep and it can't be called from any context where
253 * sleeping is not allowed.
255 void device_set_wakeup_capable(struct device *dev, bool capable)
257 if (!!dev->power.can_wakeup == !!capable)
260 if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
262 if (wakeup_sysfs_add(dev))
265 wakeup_sysfs_remove(dev);
268 dev->power.can_wakeup = capable;
270 EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
273 * device_init_wakeup - Device wakeup initialization.
274 * @dev: Device to handle.
275 * @enable: Whether or not to enable @dev as a wakeup device.
277 * By default, most devices should leave wakeup disabled. The exceptions are
278 * devices that everyone expects to be wakeup sources: keyboards, power buttons,
279 * possibly network interfaces, etc.
281 int device_init_wakeup(struct device *dev, bool enable)
286 device_set_wakeup_capable(dev, true);
287 ret = device_wakeup_enable(dev);
289 device_set_wakeup_capable(dev, false);
294 EXPORT_SYMBOL_GPL(device_init_wakeup);
297 * device_set_wakeup_enable - Enable or disable a device to wake up the system.
298 * @dev: Device to handle.
300 int device_set_wakeup_enable(struct device *dev, bool enable)
302 if (!dev || !dev->power.can_wakeup)
305 return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
307 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
310 * The functions below use the observation that each wakeup event starts a
311 * period in which the system should not be suspended. The moment this period
312 * will end depends on how the wakeup event is going to be processed after being
313 * detected and all of the possible cases can be divided into two distinct
316 * First, a wakeup event may be detected by the same functional unit that will
317 * carry out the entire processing of it and possibly will pass it to user space
318 * for further processing. In that case the functional unit that has detected
319 * the event may later "close" the "no suspend" period associated with it
320 * directly as soon as it has been dealt with. The pair of pm_stay_awake() and
321 * pm_relax(), balanced with each other, is supposed to be used in such
324 * Second, a wakeup event may be detected by one functional unit and processed
325 * by another one. In that case the unit that has detected it cannot really
326 * "close" the "no suspend" period associated with it, unless it knows in
327 * advance what's going to happen to the event during processing. This
328 * knowledge, however, may not be available to it, so it can simply specify time
329 * to wait before the system can be suspended and pass it as the second
330 * argument of pm_wakeup_event().
332 * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
333 * "no suspend" period will be ended either by the pm_relax(), or by the timer
334 * function executed when the timer expires, whichever comes first.
338 * wakup_source_activate - Mark given wakeup source as active.
339 * @ws: Wakeup source to handle.
341 * Update the @ws' statistics and, if @ws has just been activated, notify the PM
342 * core of the event by incrementing the counter of of wakeup events being
345 static void wakeup_source_activate(struct wakeup_source *ws)
349 ws->timer_expires = jiffies;
350 ws->last_time = ktime_get();
352 /* Increment the counter of events in progress. */
353 atomic_inc(&combined_event_count);
357 * __pm_stay_awake - Notify the PM core of a wakeup event.
358 * @ws: Wakeup source object associated with the source of the event.
360 * It is safe to call this function from interrupt context.
362 void __pm_stay_awake(struct wakeup_source *ws)
369 spin_lock_irqsave(&ws->lock, flags);
372 wakeup_source_activate(ws);
373 spin_unlock_irqrestore(&ws->lock, flags);
375 EXPORT_SYMBOL_GPL(__pm_stay_awake);
378 * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
379 * @dev: Device the wakeup event is related to.
381 * Notify the PM core of a wakeup event (signaled by @dev) by calling
382 * __pm_stay_awake for the @dev's wakeup source object.
384 * Call this function after detecting of a wakeup event if pm_relax() is going
385 * to be called directly after processing the event (and possibly passing it to
386 * user space for further processing).
388 void pm_stay_awake(struct device *dev)
395 spin_lock_irqsave(&dev->power.lock, flags);
396 __pm_stay_awake(dev->power.wakeup);
397 spin_unlock_irqrestore(&dev->power.lock, flags);
399 EXPORT_SYMBOL_GPL(pm_stay_awake);
402 * wakup_source_deactivate - Mark given wakeup source as inactive.
403 * @ws: Wakeup source to handle.
405 * Update the @ws' statistics and notify the PM core that the wakeup source has
406 * become inactive by decrementing the counter of wakeup events being processed
407 * and incrementing the counter of registered wakeup events.
409 static void wakeup_source_deactivate(struct wakeup_source *ws)
416 * __pm_relax() may be called directly or from a timer function.
417 * If it is called directly right after the timer function has been
418 * started, but before the timer function calls __pm_relax(), it is
419 * possible that __pm_stay_awake() will be called in the meantime and
420 * will set ws->active. Then, ws->active may be cleared immediately
421 * by the __pm_relax() called from the timer function, but in such a
422 * case ws->relax_count will be different from ws->active_count.
424 if (ws->relax_count != ws->active_count) {
432 duration = ktime_sub(now, ws->last_time);
433 ws->total_time = ktime_add(ws->total_time, duration);
434 if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
435 ws->max_time = duration;
437 del_timer(&ws->timer);
440 * Increment the counter of registered wakeup events and decrement the
441 * couter of wakeup events in progress simultaneously.
443 atomic_add(MAX_IN_PROGRESS, &combined_event_count);
447 * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
448 * @ws: Wakeup source object associated with the source of the event.
450 * Call this function for wakeup events whose processing started with calling
453 * It is safe to call it from interrupt context.
455 void __pm_relax(struct wakeup_source *ws)
462 spin_lock_irqsave(&ws->lock, flags);
464 wakeup_source_deactivate(ws);
465 spin_unlock_irqrestore(&ws->lock, flags);
467 EXPORT_SYMBOL_GPL(__pm_relax);
470 * pm_relax - Notify the PM core that processing of a wakeup event has ended.
471 * @dev: Device that signaled the event.
473 * Execute __pm_relax() for the @dev's wakeup source object.
475 void pm_relax(struct device *dev)
482 spin_lock_irqsave(&dev->power.lock, flags);
483 __pm_relax(dev->power.wakeup);
484 spin_unlock_irqrestore(&dev->power.lock, flags);
486 EXPORT_SYMBOL_GPL(pm_relax);
489 * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
490 * @data: Address of the wakeup source object associated with the event source.
492 * Call __pm_relax() for the wakeup source whose address is stored in @data.
494 static void pm_wakeup_timer_fn(unsigned long data)
496 __pm_relax((struct wakeup_source *)data);
500 * __pm_wakeup_event - Notify the PM core of a wakeup event.
501 * @ws: Wakeup source object associated with the event source.
502 * @msec: Anticipated event processing time (in milliseconds).
504 * Notify the PM core of a wakeup event whose source is @ws that will take
505 * approximately @msec milliseconds to be processed by the kernel. If @ws is
506 * not active, activate it. If @msec is nonzero, set up the @ws' timer to
507 * execute pm_wakeup_timer_fn() in future.
509 * It is safe to call this function from interrupt context.
511 void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
514 unsigned long expires;
519 spin_lock_irqsave(&ws->lock, flags);
523 wakeup_source_activate(ws);
526 wakeup_source_deactivate(ws);
530 expires = jiffies + msecs_to_jiffies(msec);
534 if (time_after(expires, ws->timer_expires)) {
535 mod_timer(&ws->timer, expires);
536 ws->timer_expires = expires;
540 spin_unlock_irqrestore(&ws->lock, flags);
542 EXPORT_SYMBOL_GPL(__pm_wakeup_event);
546 * pm_wakeup_event - Notify the PM core of a wakeup event.
547 * @dev: Device the wakeup event is related to.
548 * @msec: Anticipated event processing time (in milliseconds).
550 * Call __pm_wakeup_event() for the @dev's wakeup source object.
552 void pm_wakeup_event(struct device *dev, unsigned int msec)
559 spin_lock_irqsave(&dev->power.lock, flags);
560 __pm_wakeup_event(dev->power.wakeup, msec);
561 spin_unlock_irqrestore(&dev->power.lock, flags);
563 EXPORT_SYMBOL_GPL(pm_wakeup_event);
566 * pm_wakeup_update_hit_counts - Update hit counts of all active wakeup sources.
568 static void pm_wakeup_update_hit_counts(void)
571 struct wakeup_source *ws;
574 list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
575 spin_lock_irqsave(&ws->lock, flags);
578 spin_unlock_irqrestore(&ws->lock, flags);
584 * pm_wakeup_pending - Check if power transition in progress should be aborted.
586 * Compare the current number of registered wakeup events with its preserved
587 * value from the past and return true if new wakeup events have been registered
588 * since the old value was stored. Also return true if the current number of
589 * wakeup events being processed is different from zero.
591 bool pm_wakeup_pending(void)
596 spin_lock_irqsave(&events_lock, flags);
597 if (events_check_enabled) {
598 unsigned int cnt, inpr;
600 split_counters(&cnt, &inpr);
601 ret = (cnt != saved_count || inpr > 0);
602 events_check_enabled = !ret;
604 spin_unlock_irqrestore(&events_lock, flags);
606 pm_wakeup_update_hit_counts();
611 * pm_get_wakeup_count - Read the number of registered wakeup events.
612 * @count: Address to store the value at.
614 * Store the number of registered wakeup events at the address in @count. Block
615 * if the current number of wakeup events being processed is nonzero.
617 * Return 'false' if the wait for the number of wakeup events being processed to
618 * drop down to zero has been interrupted by a signal (and the current number
619 * of wakeup events being processed is still nonzero). Otherwise return 'true'.
621 bool pm_get_wakeup_count(unsigned int *count)
623 unsigned int cnt, inpr;
626 split_counters(&cnt, &inpr);
627 if (inpr == 0 || signal_pending(current))
629 pm_wakeup_update_hit_counts();
630 schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
633 split_counters(&cnt, &inpr);
639 * pm_save_wakeup_count - Save the current number of registered wakeup events.
640 * @count: Value to compare with the current number of registered wakeup events.
642 * If @count is equal to the current number of registered wakeup events and the
643 * current number of wakeup events being processed is zero, store @count as the
644 * old number of registered wakeup events for pm_check_wakeup_events(), enable
645 * wakeup events detection and return 'true'. Otherwise disable wakeup events
646 * detection and return 'false'.
648 bool pm_save_wakeup_count(unsigned int count)
650 unsigned int cnt, inpr;
652 events_check_enabled = false;
653 spin_lock_irq(&events_lock);
654 split_counters(&cnt, &inpr);
655 if (cnt == count && inpr == 0) {
657 events_check_enabled = true;
659 spin_unlock_irq(&events_lock);
660 if (!events_check_enabled)
661 pm_wakeup_update_hit_counts();
662 return events_check_enabled;
665 static struct dentry *wakeup_sources_stats_dentry;
668 * print_wakeup_source_stats - Print wakeup source statistics information.
669 * @m: seq_file to print the statistics into.
670 * @ws: Wakeup source object to print the statistics for.
672 static int print_wakeup_source_stats(struct seq_file *m,
673 struct wakeup_source *ws)
678 unsigned long active_count;
682 spin_lock_irqsave(&ws->lock, flags);
684 total_time = ws->total_time;
685 max_time = ws->max_time;
686 active_count = ws->active_count;
688 active_time = ktime_sub(ktime_get(), ws->last_time);
689 total_time = ktime_add(total_time, active_time);
690 if (active_time.tv64 > max_time.tv64)
691 max_time = active_time;
693 active_time = ktime_set(0, 0);
696 ret = seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t"
697 "%lld\t\t%lld\t\t%lld\t\t%lld\n",
698 ws->name, active_count, ws->event_count, ws->hit_count,
699 ktime_to_ms(active_time), ktime_to_ms(total_time),
700 ktime_to_ms(max_time), ktime_to_ms(ws->last_time));
702 spin_unlock_irqrestore(&ws->lock, flags);
708 * wakeup_sources_stats_show - Print wakeup sources statistics information.
709 * @m: seq_file to print the statistics into.
711 static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
713 struct wakeup_source *ws;
715 seq_puts(m, "name\t\tactive_count\tevent_count\thit_count\t"
716 "active_since\ttotal_time\tmax_time\tlast_change\n");
719 list_for_each_entry_rcu(ws, &wakeup_sources, entry)
720 print_wakeup_source_stats(m, ws);
726 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
728 return single_open(file, wakeup_sources_stats_show, NULL);
731 static const struct file_operations wakeup_sources_stats_fops = {
732 .owner = THIS_MODULE,
733 .open = wakeup_sources_stats_open,
736 .release = single_release,
739 static int __init wakeup_sources_debugfs_init(void)
741 wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
742 S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
746 postcore_initcall(wakeup_sources_debugfs_init);