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. Also, devices that don't generate their
280 * own wakeup requests but merely forward requests from one bus to another
281 * (like PCI bridges) should have wakeup enabled by default.
283 int device_init_wakeup(struct device *dev, bool enable)
288 device_set_wakeup_capable(dev, true);
289 ret = device_wakeup_enable(dev);
291 device_set_wakeup_capable(dev, false);
296 EXPORT_SYMBOL_GPL(device_init_wakeup);
299 * device_set_wakeup_enable - Enable or disable a device to wake up the system.
300 * @dev: Device to handle.
302 int device_set_wakeup_enable(struct device *dev, bool enable)
304 if (!dev || !dev->power.can_wakeup)
307 return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
309 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
312 * The functions below use the observation that each wakeup event starts a
313 * period in which the system should not be suspended. The moment this period
314 * will end depends on how the wakeup event is going to be processed after being
315 * detected and all of the possible cases can be divided into two distinct
318 * First, a wakeup event may be detected by the same functional unit that will
319 * carry out the entire processing of it and possibly will pass it to user space
320 * for further processing. In that case the functional unit that has detected
321 * the event may later "close" the "no suspend" period associated with it
322 * directly as soon as it has been dealt with. The pair of pm_stay_awake() and
323 * pm_relax(), balanced with each other, is supposed to be used in such
326 * Second, a wakeup event may be detected by one functional unit and processed
327 * by another one. In that case the unit that has detected it cannot really
328 * "close" the "no suspend" period associated with it, unless it knows in
329 * advance what's going to happen to the event during processing. This
330 * knowledge, however, may not be available to it, so it can simply specify time
331 * to wait before the system can be suspended and pass it as the second
332 * argument of pm_wakeup_event().
334 * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
335 * "no suspend" period will be ended either by the pm_relax(), or by the timer
336 * function executed when the timer expires, whichever comes first.
340 * wakup_source_activate - Mark given wakeup source as active.
341 * @ws: Wakeup source to handle.
343 * Update the @ws' statistics and, if @ws has just been activated, notify the PM
344 * core of the event by incrementing the counter of of wakeup events being
347 static void wakeup_source_activate(struct wakeup_source *ws)
351 ws->timer_expires = jiffies;
352 ws->last_time = ktime_get();
354 /* Increment the counter of events in progress. */
355 atomic_inc(&combined_event_count);
359 * __pm_stay_awake - Notify the PM core of a wakeup event.
360 * @ws: Wakeup source object associated with the source of the event.
362 * It is safe to call this function from interrupt context.
364 void __pm_stay_awake(struct wakeup_source *ws)
371 spin_lock_irqsave(&ws->lock, flags);
374 wakeup_source_activate(ws);
375 spin_unlock_irqrestore(&ws->lock, flags);
377 EXPORT_SYMBOL_GPL(__pm_stay_awake);
380 * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
381 * @dev: Device the wakeup event is related to.
383 * Notify the PM core of a wakeup event (signaled by @dev) by calling
384 * __pm_stay_awake for the @dev's wakeup source object.
386 * Call this function after detecting of a wakeup event if pm_relax() is going
387 * to be called directly after processing the event (and possibly passing it to
388 * user space for further processing).
390 void pm_stay_awake(struct device *dev)
397 spin_lock_irqsave(&dev->power.lock, flags);
398 __pm_stay_awake(dev->power.wakeup);
399 spin_unlock_irqrestore(&dev->power.lock, flags);
401 EXPORT_SYMBOL_GPL(pm_stay_awake);
404 * wakup_source_deactivate - Mark given wakeup source as inactive.
405 * @ws: Wakeup source to handle.
407 * Update the @ws' statistics and notify the PM core that the wakeup source has
408 * become inactive by decrementing the counter of wakeup events being processed
409 * and incrementing the counter of registered wakeup events.
411 static void wakeup_source_deactivate(struct wakeup_source *ws)
418 * __pm_relax() may be called directly or from a timer function.
419 * If it is called directly right after the timer function has been
420 * started, but before the timer function calls __pm_relax(), it is
421 * possible that __pm_stay_awake() will be called in the meantime and
422 * will set ws->active. Then, ws->active may be cleared immediately
423 * by the __pm_relax() called from the timer function, but in such a
424 * case ws->relax_count will be different from ws->active_count.
426 if (ws->relax_count != ws->active_count) {
434 duration = ktime_sub(now, ws->last_time);
435 ws->total_time = ktime_add(ws->total_time, duration);
436 if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
437 ws->max_time = duration;
439 del_timer(&ws->timer);
442 * Increment the counter of registered wakeup events and decrement the
443 * couter of wakeup events in progress simultaneously.
445 atomic_add(MAX_IN_PROGRESS, &combined_event_count);
449 * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
450 * @ws: Wakeup source object associated with the source of the event.
452 * Call this function for wakeup events whose processing started with calling
455 * It is safe to call it from interrupt context.
457 void __pm_relax(struct wakeup_source *ws)
464 spin_lock_irqsave(&ws->lock, flags);
466 wakeup_source_deactivate(ws);
467 spin_unlock_irqrestore(&ws->lock, flags);
469 EXPORT_SYMBOL_GPL(__pm_relax);
472 * pm_relax - Notify the PM core that processing of a wakeup event has ended.
473 * @dev: Device that signaled the event.
475 * Execute __pm_relax() for the @dev's wakeup source object.
477 void pm_relax(struct device *dev)
484 spin_lock_irqsave(&dev->power.lock, flags);
485 __pm_relax(dev->power.wakeup);
486 spin_unlock_irqrestore(&dev->power.lock, flags);
488 EXPORT_SYMBOL_GPL(pm_relax);
491 * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
492 * @data: Address of the wakeup source object associated with the event source.
494 * Call __pm_relax() for the wakeup source whose address is stored in @data.
496 static void pm_wakeup_timer_fn(unsigned long data)
498 __pm_relax((struct wakeup_source *)data);
502 * __pm_wakeup_event - Notify the PM core of a wakeup event.
503 * @ws: Wakeup source object associated with the event source.
504 * @msec: Anticipated event processing time (in milliseconds).
506 * Notify the PM core of a wakeup event whose source is @ws that will take
507 * approximately @msec milliseconds to be processed by the kernel. If @ws is
508 * not active, activate it. If @msec is nonzero, set up the @ws' timer to
509 * execute pm_wakeup_timer_fn() in future.
511 * It is safe to call this function from interrupt context.
513 void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
516 unsigned long expires;
521 spin_lock_irqsave(&ws->lock, flags);
525 wakeup_source_activate(ws);
528 wakeup_source_deactivate(ws);
532 expires = jiffies + msecs_to_jiffies(msec);
536 if (time_after(expires, ws->timer_expires)) {
537 mod_timer(&ws->timer, expires);
538 ws->timer_expires = expires;
542 spin_unlock_irqrestore(&ws->lock, flags);
544 EXPORT_SYMBOL_GPL(__pm_wakeup_event);
548 * pm_wakeup_event - Notify the PM core of a wakeup event.
549 * @dev: Device the wakeup event is related to.
550 * @msec: Anticipated event processing time (in milliseconds).
552 * Call __pm_wakeup_event() for the @dev's wakeup source object.
554 void pm_wakeup_event(struct device *dev, unsigned int msec)
561 spin_lock_irqsave(&dev->power.lock, flags);
562 __pm_wakeup_event(dev->power.wakeup, msec);
563 spin_unlock_irqrestore(&dev->power.lock, flags);
565 EXPORT_SYMBOL_GPL(pm_wakeup_event);
568 * pm_wakeup_update_hit_counts - Update hit counts of all active wakeup sources.
570 static void pm_wakeup_update_hit_counts(void)
573 struct wakeup_source *ws;
576 list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
577 spin_lock_irqsave(&ws->lock, flags);
580 spin_unlock_irqrestore(&ws->lock, flags);
586 * pm_wakeup_pending - Check if power transition in progress should be aborted.
588 * Compare the current number of registered wakeup events with its preserved
589 * value from the past and return true if new wakeup events have been registered
590 * since the old value was stored. Also return true if the current number of
591 * wakeup events being processed is different from zero.
593 bool pm_wakeup_pending(void)
598 spin_lock_irqsave(&events_lock, flags);
599 if (events_check_enabled) {
600 unsigned int cnt, inpr;
602 split_counters(&cnt, &inpr);
603 ret = (cnt != saved_count || inpr > 0);
604 events_check_enabled = !ret;
606 spin_unlock_irqrestore(&events_lock, flags);
608 pm_wakeup_update_hit_counts();
613 * pm_get_wakeup_count - Read the number of registered wakeup events.
614 * @count: Address to store the value at.
616 * Store the number of registered wakeup events at the address in @count. Block
617 * if the current number of wakeup events being processed is nonzero.
619 * Return 'false' if the wait for the number of wakeup events being processed to
620 * drop down to zero has been interrupted by a signal (and the current number
621 * of wakeup events being processed is still nonzero). Otherwise return 'true'.
623 bool pm_get_wakeup_count(unsigned int *count)
625 unsigned int cnt, inpr;
628 split_counters(&cnt, &inpr);
629 if (inpr == 0 || signal_pending(current))
631 pm_wakeup_update_hit_counts();
632 schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
635 split_counters(&cnt, &inpr);
641 * pm_save_wakeup_count - Save the current number of registered wakeup events.
642 * @count: Value to compare with the current number of registered wakeup events.
644 * If @count is equal to the current number of registered wakeup events and the
645 * current number of wakeup events being processed is zero, store @count as the
646 * old number of registered wakeup events for pm_check_wakeup_events(), enable
647 * wakeup events detection and return 'true'. Otherwise disable wakeup events
648 * detection and return 'false'.
650 bool pm_save_wakeup_count(unsigned int count)
652 unsigned int cnt, inpr;
654 events_check_enabled = false;
655 spin_lock_irq(&events_lock);
656 split_counters(&cnt, &inpr);
657 if (cnt == count && inpr == 0) {
659 events_check_enabled = true;
661 spin_unlock_irq(&events_lock);
662 if (!events_check_enabled)
663 pm_wakeup_update_hit_counts();
664 return events_check_enabled;
667 static struct dentry *wakeup_sources_stats_dentry;
670 * print_wakeup_source_stats - Print wakeup source statistics information.
671 * @m: seq_file to print the statistics into.
672 * @ws: Wakeup source object to print the statistics for.
674 static int print_wakeup_source_stats(struct seq_file *m,
675 struct wakeup_source *ws)
680 unsigned long active_count;
684 spin_lock_irqsave(&ws->lock, flags);
686 total_time = ws->total_time;
687 max_time = ws->max_time;
688 active_count = ws->active_count;
690 active_time = ktime_sub(ktime_get(), ws->last_time);
691 total_time = ktime_add(total_time, active_time);
692 if (active_time.tv64 > max_time.tv64)
693 max_time = active_time;
695 active_time = ktime_set(0, 0);
698 ret = seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t"
699 "%lld\t\t%lld\t\t%lld\t\t%lld\n",
700 ws->name, active_count, ws->event_count, ws->hit_count,
701 ktime_to_ms(active_time), ktime_to_ms(total_time),
702 ktime_to_ms(max_time), ktime_to_ms(ws->last_time));
704 spin_unlock_irqrestore(&ws->lock, flags);
710 * wakeup_sources_stats_show - Print wakeup sources statistics information.
711 * @m: seq_file to print the statistics into.
713 static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
715 struct wakeup_source *ws;
717 seq_puts(m, "name\t\tactive_count\tevent_count\thit_count\t"
718 "active_since\ttotal_time\tmax_time\tlast_change\n");
721 list_for_each_entry_rcu(ws, &wakeup_sources, entry)
722 print_wakeup_source_stats(m, ws);
728 static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
730 return single_open(file, wakeup_sources_stats_show, NULL);
733 static const struct file_operations wakeup_sources_stats_fops = {
734 .owner = THIS_MODULE,
735 .open = wakeup_sources_stats_open,
738 .release = single_release,
741 static int __init wakeup_sources_debugfs_init(void)
743 wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
744 S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
748 postcore_initcall(wakeup_sources_debugfs_init);