text: /*
   * drivers/base/power/wakeup.c - System wakeup events framework
   *
   * Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   *
   * This file is released under the GPLv2.
   */
  
  #include <linux/device.h>
  #include <linux/slab.h>
  #include <linux/sched/signal.h>
  #include <linux/capability.h>
  #include <linux/export.h>
  #include <linux/suspend.h>
  #include <linux/seq_file.h>
  #include <linux/debugfs.h>
  #include <linux/pm_wakeirq.h>
  #include <trace/events/power.h>
  
  #include "power.h"
  
  /*
   * If set, the suspend/hibernate code will abort transitions to a sleep state
   * if wakeup events are registered during or immediately before the transition.
   */
  bool events_check_enabled __read_mostly;
  
  /* First wakeup IRQ seen by the kernel in the last cycle. */
  unsigned int pm_wakeup_irq __read_mostly;
  
  /* If greater than 0 and the system is suspending, terminate the suspend. */
  static atomic_t pm_abort_suspend __read_mostly;
  
  /*
   * Combined counters of registered wakeup events and wakeup events in progress.
   * They need to be modified together atomically, so it's better to use one
   * atomic variable to hold them both.
   */
  static atomic_t combined_event_count = ATOMIC_INIT(0);
  
  #define IN_PROGRESS_BITS	(sizeof(int) * 4)
  #define MAX_IN_PROGRESS		((1 << IN_PROGRESS_BITS) - 1)
  
  static void split_counters(unsigned int *cnt, unsigned int *inpr)
  {
  	unsigned int comb = atomic_read(&combined_event_count);
  
  	*cnt = (comb >> IN_PROGRESS_BITS);
  	*inpr = comb & MAX_IN_PROGRESS;
  }
  
  /* A preserved old value of the events counter. */
  static unsigned int saved_count;
  
  static DEFINE_SPINLOCK(events_lock);
  
  static void pm_wakeup_timer_fn(unsigned long data);
  
  static LIST_HEAD(wakeup_sources);
  
  static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue);
  
  DEFINE_STATIC_SRCU(wakeup_srcu);
  
  static struct wakeup_source deleted_ws = {
  	.name = "deleted",
  	.lock =  __SPIN_LOCK_UNLOCKED(deleted_ws.lock),
  };
  
  /**
   * wakeup_source_prepare - Prepare a new wakeup source for initialization.
   * @ws: Wakeup source to prepare.
   * @name: Pointer to the name of the new wakeup source.
   *
   * Callers must ensure that the @name string won't be freed when @ws is still in
   * use.
   */
  void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
  {
  	if (ws) {
  		memset(ws, 0, sizeof(*ws));
  		ws->name = name;
  	}
  }
  EXPORT_SYMBOL_GPL(wakeup_source_prepare);
  
  /**
   * wakeup_source_create - Create a struct wakeup_source object.
   * @name: Name of the new wakeup source.
   */
  struct wakeup_source *wakeup_source_create(const char *name)
  {
  	struct wakeup_source *ws;
  
  	ws = kmalloc(sizeof(*ws), GFP_KERNEL);
  	if (!ws)
  		return NULL;
  
  	wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL);
  	return ws;
  }
  EXPORT_SYMBOL_GPL(wakeup_source_create);
  
  /**
   * wakeup_source_drop - Prepare a struct wakeup_source object for destruction.
   * @ws: Wakeup source to prepare for destruction.
   *
   * Callers must ensure that __pm_stay_awake() or __pm_wakeup_event() will never
   * be run in parallel with this function for the same wakeup source object.
   */
  void wakeup_source_drop(struct wakeup_source *ws)
  {
  	if (!ws)
  		return;
  
  	del_timer_sync(&ws->timer);
  	__pm_relax(ws);
  }
  EXPORT_SYMBOL_GPL(wakeup_source_drop);
  
  /*
   * Record wakeup_source statistics being deleted into a dummy wakeup_source.
   */
  static void wakeup_source_record(struct wakeup_source *ws)
  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&deleted_ws.lock, flags);
  
  	if (ws->event_count) {
  		deleted_ws.total_time =
  			ktime_add(deleted_ws.total_time, ws->total_time);
  		deleted_ws.prevent_sleep_time =
  			ktime_add(deleted_ws.prevent_sleep_time,
  				  ws->prevent_sleep_time);
  		deleted_ws.max_time =
  			ktime_compare(deleted_ws.max_time, ws->max_time) > 0 ?
  				deleted_ws.max_time : ws->max_time;
  		deleted_ws.event_count += ws->event_count;
  		deleted_ws.active_count += ws->active_count;
  		deleted_ws.relax_count += ws->relax_count;
  		deleted_ws.expire_count += ws->expire_count;
  		deleted_ws.wakeup_count += ws->wakeup_count;
  	}
  
  	spin_unlock_irqrestore(&deleted_ws.lock, flags);
  }
  
  /**
   * wakeup_source_destroy - Destroy a struct wakeup_source object.
   * @ws: Wakeup source to destroy.
   *
   * Use only for wakeup source objects created with wakeup_source_create().
   */
  void wakeup_source_destroy(struct wakeup_source *ws)
  {
  	if (!ws)
  		return;
  
  	wakeup_source_drop(ws);
  	wakeup_source_record(ws);
  	kfree_const(ws->name);
  	kfree(ws);
  }
  EXPORT_SYMBOL_GPL(wakeup_source_destroy);
  
  /**
   * wakeup_source_add - Add given object to the list of wakeup sources.
   * @ws: Wakeup source object to add to the list.
   */
  void wakeup_source_add(struct wakeup_source *ws)
  {
  	unsigned long flags;
  
  	if (WARN_ON(!ws))
  		return;
  
  	spin_lock_init(&ws->lock);
  	setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
  	ws->active = false;
  	ws->last_time = ktime_get();
  
  	spin_lock_irqsave(&events_lock, flags);
  	list_add_rcu(&ws->entry, &wakeup_sources);
  	spin_unlock_irqrestore(&events_lock, flags);
  }
  EXPORT_SYMBOL_GPL(wakeup_source_add);
  
  /**
   * wakeup_source_remove - Remove given object from the wakeup sources list.
   * @ws: Wakeup source object to remove from the list.
   */
  void wakeup_source_remove(struct wakeup_source *ws)
  {
  	unsigned long flags;
  
  	if (WARN_ON(!ws))
  		return;
  
  	spin_lock_irqsave(&events_lock, flags);
  	list_del_rcu(&ws->entry);
  	spin_unlock_irqrestore(&events_lock, flags);
  	synchronize_srcu(&wakeup_srcu);
  }
  EXPORT_SYMBOL_GPL(wakeup_source_remove);
  
  /**
   * wakeup_source_register - Create wakeup source and add it to the list.
   * @name: Name of the wakeup source to register.
   */
  struct wakeup_source *wakeup_source_register(const char *name)
  {
  	struct wakeup_source *ws;
  
  	ws = wakeup_source_create(name);
  	if (ws)
  		wakeup_source_add(ws);
  
  	return ws;
  }
  EXPORT_SYMBOL_GPL(wakeup_source_register);
  
  /**
   * wakeup_source_unregister - Remove wakeup source from the list and remove it.
   * @ws: Wakeup source object to unregister.
   */
  void wakeup_source_unregister(struct wakeup_source *ws)
  {
  	if (ws) {
  		wakeup_source_remove(ws);
  		wakeup_source_destroy(ws);
  	}
  }
  EXPORT_SYMBOL_GPL(wakeup_source_unregister);
  
  /**
   * device_wakeup_attach - Attach a wakeup source object to a device object.
   * @dev: Device to handle.
   * @ws: Wakeup source object to attach to @dev.
   *
   * This causes @dev to be treated as a wakeup device.
   */
  static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
  {
  	spin_lock_irq(&dev->power.lock);
  	if (dev->power.wakeup) {
  		spin_unlock_irq(&dev->power.lock);
  		return -EEXIST;
  	}
  	dev->power.wakeup = ws;
  	if (dev->power.wakeirq)
  		device_wakeup_attach_irq(dev, dev->power.wakeirq);
  	spin_unlock_irq(&dev->power.lock);
  	return 0;
  }
  
  /**
   * device_wakeup_enable - Enable given device to be a wakeup source.
   * @dev: Device to handle.
   *
   * Create a wakeup source object, register it and attach it to @dev.
   */
  int device_wakeup_enable(struct device *dev)
  {
  	struct wakeup_source *ws;
  	int ret;
  
  	if (!dev || !dev->power.can_wakeup)
  		return -EINVAL;
  
  	ws = wakeup_source_register(dev_name(dev));
  	if (!ws)
  		return -ENOMEM;
  
  	ret = device_wakeup_attach(dev, ws);
  	if (ret)
  		wakeup_source_unregister(ws);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(device_wakeup_enable);
  
  /**
   * device_wakeup_attach_irq - Attach a wakeirq to a wakeup source
   * @dev: Device to handle
   * @wakeirq: Device specific wakeirq entry
   *
   * Attach a device wakeirq to the wakeup source so the device
   * wake IRQ can be configured automatically for suspend and
   * resume.
   *
   * Call under the device's power.lock lock.
   */
  int device_wakeup_attach_irq(struct device *dev,
  			     struct wake_irq *wakeirq)
  {
  	struct wakeup_source *ws;
  
  	ws = dev->power.wakeup;
  	if (!ws) {
  		dev_err(dev, "forgot to call call device_init_wakeup?\n");
  		return -EINVAL;
  	}
  
  	if (ws->wakeirq)
  		return -EEXIST;
  
  	ws->wakeirq = wakeirq;
  	return 0;
  }
  
  /**
   * device_wakeup_detach_irq - Detach a wakeirq from a wakeup source
   * @dev: Device to handle
   *
   * Removes a device wakeirq from the wakeup source.
   *
   * Call under the device's power.lock lock.
   */
  void device_wakeup_detach_irq(struct device *dev)
  {
  	struct wakeup_source *ws;
  
  	ws = dev->power.wakeup;
  	if (ws)
  		ws->wakeirq = NULL;
  }
  
  /**
   * device_wakeup_arm_wake_irqs(void)
   *
   * Itereates over the list of device wakeirqs to arm them.
   */
  void device_wakeup_arm_wake_irqs(void)
  {
  	struct wakeup_source *ws;
  	int srcuidx;
  
  	srcuidx = srcu_read_lock(&wakeup_srcu);
  	list_for_each_entry_rcu(ws, &wakeup_sources, entry)
  		dev_pm_arm_wake_irq(ws->wakeirq);
  	srcu_read_unlock(&wakeup_srcu, srcuidx);
  }
  
  /**
   * device_wakeup_disarm_wake_irqs(void)
   *
   * Itereates over the list of device wakeirqs to disarm them.
   */
  void device_wakeup_disarm_wake_irqs(void)
  {
  	struct wakeup_source *ws;
  	int srcuidx;
  
  	srcuidx = srcu_read_lock(&wakeup_srcu);
  	list_for_each_entry_rcu(ws, &wakeup_sources, entry)
  		dev_pm_disarm_wake_irq(ws->wakeirq);
  	srcu_read_unlock(&wakeup_srcu, srcuidx);
  }
  
  /**
   * device_wakeup_detach - Detach a device's wakeup source object from it.
   * @dev: Device to detach the wakeup source object from.
   *
   * After it returns, @dev will not be treated as a wakeup device any more.
   */
  static struct wakeup_source *device_wakeup_detach(struct device *dev)
  {
  	struct wakeup_source *ws;
  
  	spin_lock_irq(&dev->power.lock);
  	ws = dev->power.wakeup;
  	dev->power.wakeup = NULL;
  	spin_unlock_irq(&dev->power.lock);
  	return ws;
  }
  
  /**
   * device_wakeup_disable - Do not regard a device as a wakeup source any more.
   * @dev: Device to handle.
   *
   * Detach the @dev's wakeup source object from it, unregister this wakeup source
   * object and destroy it.
   */
  int device_wakeup_disable(struct device *dev)
  {
  	struct wakeup_source *ws;
  
  	if (!dev || !dev->power.can_wakeup)
  		return -EINVAL;
  
  	ws = device_wakeup_detach(dev);
  	wakeup_source_unregister(ws);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(device_wakeup_disable);
  
  /**
   * device_set_wakeup_capable - Set/reset device wakeup capability flag.
   * @dev: Device to handle.
   * @capable: Whether or not @dev is capable of waking up the system from sleep.
   *
   * If @capable is set, set the @dev's power.can_wakeup flag and add its
   * wakeup-related attributes to sysfs.  Otherwise, unset the @dev's
   * power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
   *
   * This function may sleep and it can't be called from any context where
   * sleeping is not allowed.
   */
  void device_set_wakeup_capable(struct device *dev, bool capable)
  {
  	if (!!dev->power.can_wakeup == !!capable)
  		return;
  
  	dev->power.can_wakeup = capable;
  	if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
  		if (capable) {
  			int ret = wakeup_sysfs_add(dev);
  
  			if (ret)
  				dev_info(dev, "Wakeup sysfs attributes not added\n");
  		} else {
  			wakeup_sysfs_remove(dev);
  		}
  	}
  }
  EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
  
  /**
   * device_init_wakeup - Device wakeup initialization.
   * @dev: Device to handle.
   * @enable: Whether or not to enable @dev as a wakeup device.
   *
   * By default, most devices should leave wakeup disabled.  The exceptions are
   * devices that everyone expects to be wakeup sources: keyboards, power buttons,
   * possibly network interfaces, etc.  Also, devices that don't generate their
   * own wakeup requests but merely forward requests from one bus to another
   * (like PCI bridges) should have wakeup enabled by default.
   */
  int device_init_wakeup(struct device *dev, bool enable)
  {
  	int ret = 0;
  
  	if (!dev)
  		return -EINVAL;
  
  	if (enable) {
  		device_set_wakeup_capable(dev, true);
  		ret = device_wakeup_enable(dev);
  	} else {
  		if (dev->power.can_wakeup)
  			device_wakeup_disable(dev);
  
  		device_set_wakeup_capable(dev, false);
  	}
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(device_init_wakeup);
  
  /**
   * device_set_wakeup_enable - Enable or disable a device to wake up the system.
   * @dev: Device to handle.
   */
  int device_set_wakeup_enable(struct device *dev, bool enable)
  {
  	if (!dev || !dev->power.can_wakeup)
  		return -EINVAL;
  
  	return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
  }
  EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
  
  /**
   * wakeup_source_not_registered - validate the given wakeup source.
   * @ws: Wakeup source to be validated.
   */
  static bool wakeup_source_not_registered(struct wakeup_source *ws)
  {
  	/*
  	 * Use timer struct to check if the given source is initialized
  	 * by wakeup_source_add.
  	 */
  	return ws->timer.function != pm_wakeup_timer_fn ||
  		   ws->timer.data != (unsigned long)ws;
  }
  
  /*
   * The functions below use the observation that each wakeup event starts a
   * period in which the system should not be suspended.  The moment this period
   * will end depends on how the wakeup event is going to be processed after being
   * detected and all of the possible cases can be divided into two distinct
   * groups.
   *
   * First, a wakeup event may be detected by the same functional unit that will
   * carry out the entire processing of it and possibly will pass it to user space
   * for further processing.  In that case the functional unit that has detected
   * the event may later "close" the "no suspend" period associated with it
   * directly as soon as it has been dealt with.  The pair of pm_stay_awake() and
   * pm_relax(), balanced with each other, is supposed to be used in such
   * situations.
   *
   * Second, a wakeup event may be detected by one functional unit and processed
   * by another one.  In that case the unit that has detected it cannot really
   * "close" the "no suspend" period associated with it, unless it knows in
   * advance what's going to happen to the event during processing.  This
   * knowledge, however, may not be available to it, so it can simply specify time
   * to wait before the system can be suspended and pass it as the second
   * argument of pm_wakeup_event().
   *
   * It is valid to call pm_relax() after pm_wakeup_event(), in which case the
   * "no suspend" period will be ended either by the pm_relax(), or by the timer
   * function executed when the timer expires, whichever comes first.
   */
  
  /**
   * wakup_source_activate - Mark given wakeup source as active.
   * @ws: Wakeup source to handle.
   *
   * Update the @ws' statistics and, if @ws has just been activated, notify the PM
   * core of the event by incrementing the counter of of wakeup events being
   * processed.
   */
  static void wakeup_source_activate(struct wakeup_source *ws)
  {
  	unsigned int cec;
  
  	if (WARN_ONCE(wakeup_source_not_registered(ws),
  			"unregistered wakeup source\n"))
  		return;
  
  	ws->active = true;
  	ws->active_count++;
  	ws->last_time = ktime_get();
  	if (ws->autosleep_enabled)
  		ws->start_prevent_time = ws->last_time;
  
  	/* Increment the counter of events in progress. */
  	cec = atomic_inc_return(&combined_event_count);
  
  	trace_wakeup_source_activate(ws->name, cec);
  }
  
  /**
   * wakeup_source_report_event - Report wakeup event using the given source.
   * @ws: Wakeup source to report the event for.
   * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
   */
  static void wakeup_source_report_event(struct wakeup_source *ws, bool hard)
  {
  	ws->event_count++;
  	/* This is racy, but the counter is approximate anyway. */
  	if (events_check_enabled)
  		ws->wakeup_count++;
  
  	if (!ws->active)
  		wakeup_source_activate(ws);
  
  	if (hard)
  		pm_system_wakeup();
  }
  
  /**
   * __pm_stay_awake - Notify the PM core of a wakeup event.
   * @ws: Wakeup source object associated with the source of the event.
   *
   * It is safe to call this function from interrupt context.
   */
  void __pm_stay_awake(struct wakeup_source *ws)
  {
  	unsigned long flags;
  
  	if (!ws)
  		return;
  
  	spin_lock_irqsave(&ws->lock, flags);
  
  	wakeup_source_report_event(ws, false);
  	del_timer(&ws->timer);
  	ws->timer_expires = 0;
  
  	spin_unlock_irqrestore(&ws->lock, flags);
  }
  EXPORT_SYMBOL_GPL(__pm_stay_awake);
  
  /**
   * pm_stay_awake - Notify the PM core that a wakeup event is being processed.
   * @dev: Device the wakeup event is related to.
   *
   * Notify the PM core of a wakeup event (signaled by @dev) by calling
   * __pm_stay_awake for the @dev's wakeup source object.
   *
   * Call this function after detecting of a wakeup event if pm_relax() is going
   * to be called directly after processing the event (and possibly passing it to
   * user space for further processing).
   */
  void pm_stay_awake(struct device *dev)
  {
  	unsigned long flags;
  
  	if (!dev)
  		return;
  
  	spin_lock_irqsave(&dev->power.lock, flags);
  	__pm_stay_awake(dev->power.wakeup);
  	spin_unlock_irqrestore(&dev->power.lock, flags);
  }
  EXPORT_SYMBOL_GPL(pm_stay_awake);
  
  #ifdef CONFIG_PM_AUTOSLEEP
  static void update_prevent_sleep_time(struct wakeup_source *ws, ktime_t now)
  {
  	ktime_t delta = ktime_sub(now, ws->start_prevent_time);
  	ws->prevent_sleep_time = ktime_add(ws->prevent_sleep_time, delta);
  }
  #else
  static inline void update_prevent_sleep_time(struct wakeup_source *ws,
  					     ktime_t now) {}
  #endif
  
  /**
   * wakup_source_deactivate - Mark given wakeup source as inactive.
   * @ws: Wakeup source to handle.
   *
   * Update the @ws' statistics and notify the PM core that the wakeup source has
   * become inactive by decrementing the counter of wakeup events being processed
   * and incrementing the counter of registered wakeup events.
   */
  static void wakeup_source_deactivate(struct wakeup_source *ws)
  {
  	unsigned int cnt, inpr, cec;
  	ktime_t duration;
  	ktime_t now;
  
  	ws->relax_count++;
  	/*
  	 * __pm_relax() may be called directly or from a timer function.
  	 * If it is called directly right after the timer function has been
  	 * started, but before the timer function calls __pm_relax(), it is
  	 * possible that __pm_stay_awake() will be called in the meantime and
  	 * will set ws->active.  Then, ws->active may be cleared immediately
  	 * by the __pm_relax() called from the timer function, but in such a
  	 * case ws->relax_count will be different from ws->active_count.
  	 */
  	if (ws->relax_count != ws->active_count) {
  		ws->relax_count--;
  		return;
  	}
  
  	ws->active = false;
  
  	now = ktime_get();
  	duration = ktime_sub(now, ws->last_time);
  	ws->total_time = ktime_add(ws->total_time, duration);
  	if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
  		ws->max_time = duration;
  
  	ws->last_time = now;
  	del_timer(&ws->timer);
  	ws->timer_expires = 0;
  
  	if (ws->autosleep_enabled)
  		update_prevent_sleep_time(ws, now);
  
  	/*
  	 * Increment the counter of registered wakeup events and decrement the
  	 * couter of wakeup events in progress simultaneously.
  	 */
  	cec = atomic_add_return(MAX_IN_PROGRESS, &combined_event_count);
  	trace_wakeup_source_deactivate(ws->name, cec);
  
  	split_counters(&cnt, &inpr);
  	if (!inpr && waitqueue_active(&wakeup_count_wait_queue))
  		wake_up(&wakeup_count_wait_queue);
  }
  
  /**
   * __pm_relax - Notify the PM core that processing of a wakeup event has ended.
   * @ws: Wakeup source object associated with the source of the event.
   *
   * Call this function for wakeup events whose processing started with calling
   * __pm_stay_awake().
   *
   * It is safe to call it from interrupt context.
   */
  void __pm_relax(struct wakeup_source *ws)
  {
  	unsigned long flags;
  
  	if (!ws)
  		return;
  
  	spin_lock_irqsave(&ws->lock, flags);
  	if (ws->active)
  		wakeup_source_deactivate(ws);
  	spin_unlock_irqrestore(&ws->lock, flags);
  }
  EXPORT_SYMBOL_GPL(__pm_relax);
  
  /**
   * pm_relax - Notify the PM core that processing of a wakeup event has ended.
   * @dev: Device that signaled the event.
   *
   * Execute __pm_relax() for the @dev's wakeup source object.
   */
  void pm_relax(struct device *dev)
  {
  	unsigned long flags;
  
  	if (!dev)
  		return;
  
  	spin_lock_irqsave(&dev->power.lock, flags);
  	__pm_relax(dev->power.wakeup);
  	spin_unlock_irqrestore(&dev->power.lock, flags);
  }
  EXPORT_SYMBOL_GPL(pm_relax);
  
  /**
   * pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
   * @data: Address of the wakeup source object associated with the event source.
   *
   * Call wakeup_source_deactivate() for the wakeup source whose address is stored
   * in @data if it is currently active and its timer has not been canceled and
   * the expiration time of the timer is not in future.
   */
  static void pm_wakeup_timer_fn(unsigned long data)
  {
  	struct wakeup_source *ws = (struct wakeup_source *)data;
  	unsigned long flags;
  
  	spin_lock_irqsave(&ws->lock, flags);
  
  	if (ws->active && ws->timer_expires
  	    && time_after_eq(jiffies, ws->timer_expires)) {
  		wakeup_source_deactivate(ws);
  		ws->expire_count++;
  	}
  
  	spin_unlock_irqrestore(&ws->lock, flags);
  }
  
  /**
   * pm_wakeup_ws_event - Notify the PM core of a wakeup event.
   * @ws: Wakeup source object associated with the event source.
   * @msec: Anticipated event processing time (in milliseconds).
   * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
   *
   * Notify the PM core of a wakeup event whose source is @ws that will take
   * approximately @msec milliseconds to be processed by the kernel.  If @ws is
   * not active, activate it.  If @msec is nonzero, set up the @ws' timer to
   * execute pm_wakeup_timer_fn() in future.
   *
   * It is safe to call this function from interrupt context.
   */
  void pm_wakeup_ws_event(struct wakeup_source *ws, unsigned int msec, bool hard)
  {
  	unsigned long flags;
  	unsigned long expires;
  
  	if (!ws)
  		return;
  
  	spin_lock_irqsave(&ws->lock, flags);
  
  	wakeup_source_report_event(ws, hard);
  
  	if (!msec) {
  		wakeup_source_deactivate(ws);
  		goto unlock;
  	}
  
  	expires = jiffies + msecs_to_jiffies(msec);
  	if (!expires)
  		expires = 1;
  
  	if (!ws->timer_expires || time_after(expires, ws->timer_expires)) {
  		mod_timer(&ws->timer, expires);
  		ws->timer_expires = expires;
  	}
  
   unlock:
  	spin_unlock_irqrestore(&ws->lock, flags);
  }
  EXPORT_SYMBOL_GPL(pm_wakeup_ws_event);
  
  /**
   * pm_wakeup_event - Notify the PM core of a wakeup event.
   * @dev: Device the wakeup event is related to.
   * @msec: Anticipated event processing time (in milliseconds).
   * @hard: If set, abort suspends in progress and wake up from suspend-to-idle.
   *
   * Call pm_wakeup_ws_event() for the @dev's wakeup source object.
   */
  void pm_wakeup_dev_event(struct device *dev, unsigned int msec, bool hard)
  {
  	unsigned long flags;
  
  	if (!dev)
  		return;
  
  	spin_lock_irqsave(&dev->power.lock, flags);
  	pm_wakeup_ws_event(dev->power.wakeup, msec, hard);
  	spin_unlock_irqrestore(&dev->power.lock, flags);
  }
  EXPORT_SYMBOL_GPL(pm_wakeup_dev_event);
  
  void pm_print_active_wakeup_sources(void)
  {
  	struct wakeup_source *ws;
  	int srcuidx, active = 0;
  	struct wakeup_source *last_activity_ws = NULL;
  
  	srcuidx = srcu_read_lock(&wakeup_srcu);
  	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
  		if (ws->active) {
  			pr_debug("active wakeup source: %s\n", ws->name);
  			active = 1;
  		} else if (!active &&
  			   (!last_activity_ws ||
  			    ktime_to_ns(ws->last_time) >
  			    ktime_to_ns(last_activity_ws->last_time))) {
  			last_activity_ws = ws;
  		}
  	}
  
  	if (!active && last_activity_ws)
  		pr_debug("last active wakeup source: %s\n",
  			last_activity_ws->name);
  	srcu_read_unlock(&wakeup_srcu, srcuidx);
  }
  EXPORT_SYMBOL_GPL(pm_print_active_wakeup_sources);
  
  /**
   * pm_wakeup_pending - Check if power transition in progress should be aborted.
   *
   * Compare the current number of registered wakeup events with its preserved
   * value from the past and return true if new wakeup events have been registered
   * since the old value was stored.  Also return true if the current number of
   * wakeup events being processed is different from zero.
   */
  bool pm_wakeup_pending(void)
  {
  	unsigned long flags;
  	bool ret = false;
  
  	spin_lock_irqsave(&events_lock, flags);
  	if (events_check_enabled) {
  		unsigned int cnt, inpr;
  
  		split_counters(&cnt, &inpr);
  		ret = (cnt != saved_count || inpr > 0);
  		events_check_enabled = !ret;
  	}
  	spin_unlock_irqrestore(&events_lock, flags);
  
  	if (ret) {
  		pr_info("PM: Wakeup pending, aborting suspend\n");
  		pm_print_active_wakeup_sources();
  	}
  
  	return ret || atomic_read(&pm_abort_suspend) > 0;
  }
  
  void pm_system_wakeup(void)
  {
  	atomic_inc(&pm_abort_suspend);
  	s2idle_wake();
  }
  EXPORT_SYMBOL_GPL(pm_system_wakeup);
  
  void pm_system_cancel_wakeup(void)
  {
  	atomic_dec(&pm_abort_suspend);
  }
  
  void pm_wakeup_clear(bool reset)
  {
  	pm_wakeup_irq = 0;
  	if (reset)
  		atomic_set(&pm_abort_suspend, 0);
  }
  
  void pm_system_irq_wakeup(unsigned int irq_number)
  {
  	if (pm_wakeup_irq == 0) {
  		pm_wakeup_irq = irq_number;
  		pm_system_wakeup();
  	}
  }
  
  /**
   * pm_get_wakeup_count - Read the number of registered wakeup events.
   * @count: Address to store the value at.
   * @block: Whether or not to block.
   *
   * Store the number of registered wakeup events at the address in @count.  If
   * @block is set, block until the current number of wakeup events being
   * processed is zero.
   *
   * Return 'false' if the current number of wakeup events being processed is
   * nonzero.  Otherwise return 'true'.
   */
  bool pm_get_wakeup_count(unsigned int *count, bool block)
  {
  	unsigned int cnt, inpr;
  
  	if (block) {
  		DEFINE_WAIT(wait);
  
  		for (;;) {
  			prepare_to_wait(&wakeup_count_wait_queue, &wait,
  					TASK_INTERRUPTIBLE);
  			split_counters(&cnt, &inpr);
  			if (inpr == 0 || signal_pending(current))
  				break;
  			pm_print_active_wakeup_sources();
  			schedule();
  		}
  		finish_wait(&wakeup_count_wait_queue, &wait);
  	}
  
  	split_counters(&cnt, &inpr);
  	*count = cnt;
  	return !inpr;
  }
  
  /**
   * pm_save_wakeup_count - Save the current number of registered wakeup events.
   * @count: Value to compare with the current number of registered wakeup events.
   *
   * If @count is equal to the current number of registered wakeup events and the
   * current number of wakeup events being processed is zero, store @count as the
   * old number of registered wakeup events for pm_check_wakeup_events(), enable
   * wakeup events detection and return 'true'.  Otherwise disable wakeup events
   * detection and return 'false'.
   */
  bool pm_save_wakeup_count(unsigned int count)
  {
  	unsigned int cnt, inpr;
  	unsigned long flags;
  
  	events_check_enabled = false;
  	spin_lock_irqsave(&events_lock, flags);
  	split_counters(&cnt, &inpr);
  	if (cnt == count && inpr == 0) {
  		saved_count = count;
  		events_check_enabled = true;
  	}
  	spin_unlock_irqrestore(&events_lock, flags);
  	return events_check_enabled;
  }
  
  #ifdef CONFIG_PM_AUTOSLEEP
  /**
   * pm_wakep_autosleep_enabled - Modify autosleep_enabled for all wakeup sources.
   * @enabled: Whether to set or to clear the autosleep_enabled flags.
   */
  void pm_wakep_autosleep_enabled(bool set)
  {
  	struct wakeup_source *ws;
  	ktime_t now = ktime_get();
  	int srcuidx;
  
  	srcuidx = srcu_read_lock(&wakeup_srcu);
  	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
  		spin_lock_irq(&ws->lock);
  		if (ws->autosleep_enabled != set) {
  			ws->autosleep_enabled = set;
  			if (ws->active) {
  				if (set)
  					ws->start_prevent_time = now;
  				else
  					update_prevent_sleep_time(ws, now);
  			}
  		}
  		spin_unlock_irq(&ws->lock);
  	}
  	srcu_read_unlock(&wakeup_srcu, srcuidx);
  }
  #endif /* CONFIG_PM_AUTOSLEEP */
  
  static struct dentry *wakeup_sources_stats_dentry;
  
  /**
   * print_wakeup_source_stats - Print wakeup source statistics information.
   * @m: seq_file to print the statistics into.
   * @ws: Wakeup source object to print the statistics for.
   */
  static int print_wakeup_source_stats(struct seq_file *m,
  				     struct wakeup_source *ws)
  {
  	unsigned long flags;
  	ktime_t total_time;
  	ktime_t max_time;
  	unsigned long active_count;
  	ktime_t active_time;
  	ktime_t prevent_sleep_time;
  
  	spin_lock_irqsave(&ws->lock, flags);
  
  	total_time = ws->total_time;
  	max_time = ws->max_time;
  	prevent_sleep_time = ws->prevent_sleep_time;
  	active_count = ws->active_count;
  	if (ws->active) {
  		ktime_t now = ktime_get();
  
  		active_time = ktime_sub(now, ws->last_time);
  		total_time = ktime_add(total_time, active_time);
  		if (active_time > max_time)
  			max_time = active_time;
  
  		if (ws->autosleep_enabled)
  			prevent_sleep_time = ktime_add(prevent_sleep_time,
  				ktime_sub(now, ws->start_prevent_time));
  	} else {
  		active_time = 0;
  	}
  
  	seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t%lu\t\t%lld\t\t%lld\t\t%lld\t\t%lld\t\t%lld\n",
  		   ws->name, active_count, ws->event_count,
  		   ws->wakeup_count, ws->expire_count,
  		   ktime_to_ms(active_time), ktime_to_ms(total_time),
  		   ktime_to_ms(max_time), ktime_to_ms(ws->last_time),
  		   ktime_to_ms(prevent_sleep_time));
  
  	spin_unlock_irqrestore(&ws->lock, flags);
  
  	return 0;
  }
  
  /**
   * wakeup_sources_stats_show - Print wakeup sources statistics information.
   * @m: seq_file to print the statistics into.
   */
  static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
  {
  	struct wakeup_source *ws;
  	int srcuidx;
  
  	seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
  		"expire_count\tactive_since\ttotal_time\tmax_time\t"
  		"last_change\tprevent_suspend_time\n");
  
  	srcuidx = srcu_read_lock(&wakeup_srcu);
  	list_for_each_entry_rcu(ws, &wakeup_sources, entry)
  		print_wakeup_source_stats(m, ws);
  	srcu_read_unlock(&wakeup_srcu, srcuidx);
  
  	print_wakeup_source_stats(m, &deleted_ws);
  
  	return 0;
  }
  
  static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, wakeup_sources_stats_show, NULL);
  }
  
  static const struct file_operations wakeup_sources_stats_fops = {
  	.owner = THIS_MODULE,
  	.open = wakeup_sources_stats_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = single_release,
  };
  
  static int __init wakeup_sources_debugfs_init(void)
  {
  	wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
  			S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
  	return 0;
  }
  
  postcore_initcall(wakeup_sources_debugfs_init);
  