1 files changed, 598 insertions, 99 deletions

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index eb594facfc3f..84f7c7d5a098 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -11,7 +11,12 @@
 #include <linux/sched.h>
 #include <linux/capability.h>
 #include <linux/suspend.h>
-#include <linux/pm.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+
+#include "power.h"
+
+#define TIMEOUT         100
 
 /*
  * If set, the suspend/hibernate code will abort transitions to a sleep state
@@ -19,19 +24,287 @@
  */
 bool events_check_enabled;
 
-/* The counter of registered wakeup events. */
-static unsigned long event_count;
-/* A preserved old value of event_count. */
-static unsigned long saved_event_count;
-/* The counter of wakeup events being processed. */
-static unsigned long events_in_progress;
+/*
+ * 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 DEFINE_TIMER(events_timer, pm_wakeup_timer_fn, 0, 0);
-static unsigned long events_timer_expires;
+static LIST_HEAD(wakeup_sources);
+
+/**
+ * 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 = kzalloc(sizeof(*ws), GFP_KERNEL);
+        if (!ws)
+                return NULL;
+
+        spin_lock_init(&ws->lock);
+        if (name)
+                ws->name = kstrdup(name, GFP_KERNEL);
+
+        return ws;
+}
+EXPORT_SYMBOL_GPL(wakeup_source_create);
+
+/**
+ * wakeup_source_destroy - Destroy a struct wakeup_source object.
+ * @ws: Wakeup source to destroy.
+ */
+void wakeup_source_destroy(struct wakeup_source *ws)
+{
+        if (!ws)
+                return;
+
+        spin_lock_irq(&ws->lock);
+        while (ws->active) {
+                spin_unlock_irq(&ws->lock);
+
+                schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
+
+                spin_lock_irq(&ws->lock);
+        }
+        spin_unlock_irq(&ws->lock);
+
+        kfree(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)
+{
+        if (WARN_ON(!ws))
+                return;
+
+        setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
+        ws->active = false;
+
+        spin_lock_irq(&events_lock);
+        list_add_rcu(&ws->entry, &wakeup_sources);
+        spin_unlock_irq(&events_lock);
+}
+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)
+{
+        if (WARN_ON(!ws))
+                return;
+
+        spin_lock_irq(&events_lock);
+        list_del_rcu(&ws->entry);
+        spin_unlock_irq(&events_lock);
+        synchronize_rcu();
+}
+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)
+{
+        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;
+        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_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);
+        if (ws)
+                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;
+
+        if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
+                if (capable) {
+                        if (wakeup_sysfs_add(dev))
+                                return;
+                } else {
+                        wakeup_sysfs_remove(dev);
+                }
+        }
+        dev->power.can_wakeup = capable;
+}
+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.
+ */
+int device_init_wakeup(struct device *dev, bool enable)
+{
+        int ret = 0;
+
+        if (enable) {
+                device_set_wakeup_capable(dev, true);
+                ret = device_wakeup_enable(dev);
+        } else {
+                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);
 
 /*
  * The functions below use the observation that each wakeup event starts a
@@ -55,139 +328,282 @@ static unsigned long events_timer_expires;
  * 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)
+{
+        ws->active = true;
+        ws->active_count++;
+        ws->timer_expires = jiffies;
+        ws->last_time = ktime_get();
+
+        /* Increment the counter of events in progress. */
+        atomic_inc(&combined_event_count);
+}
+
+/**
+ * __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);
+        ws->event_count++;
+        if (!ws->active)
+                wakeup_source_activate(ws);
+        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 incrementing the
- * counter of wakeup events being processed.  If @dev is not NULL, the counter
- * of wakeup events related to @dev is incremented too.
+ * 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).
- *
- * It is safe to call this function from interrupt context.
  */
 void pm_stay_awake(struct device *dev)
 {
         unsigned long flags;
 
-        spin_lock_irqsave(&events_lock, flags);
-        if (dev)
-                dev->power.wakeup_count++;
+        if (!dev)
+                return;
 
-        events_in_progress++;
-        spin_unlock_irqrestore(&events_lock, flags);
+        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);
 
 /**
- * pm_relax - Notify the PM core that processing of a wakeup event has ended.
+ * wakup_source_deactivate - Mark given wakeup source as inactive.
+ * @ws: Wakeup source to handle.
  *
- * Notify the PM core that a wakeup event has been processed by decrementing
- * the counter of wakeup events being processed and incrementing the counter
- * of registered wakeup events.
+ * 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)
+{
+        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;
+
+        del_timer(&ws->timer);
+
+        /*
+         * Increment the counter of registered wakeup events and decrement the
+         * couter of wakeup events in progress simultaneously.
+         */
+        atomic_add(MAX_IN_PROGRESS, &combined_event_count);
+}
+
+/**
+ * __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().
+ * __pm_stay_awake().
  *
  * It is safe to call it from interrupt context.
  */
-void pm_relax(void)
+void __pm_relax(struct wakeup_source *ws)
 {
         unsigned long flags;
 
-        spin_lock_irqsave(&events_lock, flags);
-        if (events_in_progress) {
-                events_in_progress--;
-                event_count++;
-        }
-        spin_unlock_irqrestore(&events_lock, 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.
  *
- * Decrease the counter of wakeup events being processed after it was increased
- * by pm_wakeup_event().
+ * Call __pm_relax() for the wakeup source whose address is stored in @data.
  */
 static void pm_wakeup_timer_fn(unsigned long data)
 {
+        __pm_relax((struct wakeup_source *)data);
+}
+
+/**
+ * __pm_wakeup_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).
+ *
+ * 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_event(struct wakeup_source *ws, unsigned int msec)
+{
         unsigned long flags;
+        unsigned long expires;
 
-        spin_lock_irqsave(&events_lock, flags);
-        if (events_timer_expires
-            && time_before_eq(events_timer_expires, jiffies)) {
-                events_in_progress--;
-                events_timer_expires = 0;
+        if (!ws)
+                return;
+
+        spin_lock_irqsave(&ws->lock, flags);
+
+        ws->event_count++;
+        if (!ws->active)
+                wakeup_source_activate(ws);
+
+        if (!msec) {
+                wakeup_source_deactivate(ws);
+                goto unlock;
         }
-        spin_unlock_irqrestore(&events_lock, flags);
+
+        expires = jiffies + msecs_to_jiffies(msec);
+        if (!expires)
+                expires = 1;
+
+        if (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_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).
  *
- * Notify the PM core of a wakeup event (signaled by @dev) that will take
- * approximately @msec milliseconds to be processed by the kernel.  Increment
- * the counter of registered wakeup events and (if @msec is nonzero) set up
- * the wakeup events timer to execute pm_wakeup_timer_fn() in future (if the
- * timer has not been set up already, increment the counter of wakeup events
- * being processed).  If @dev is not NULL, the counter of wakeup events related
- * to @dev is incremented too.
- *
- * It is safe to call this function from interrupt context.
+ * Call __pm_wakeup_event() for the @dev's wakeup source object.
  */
 void pm_wakeup_event(struct device *dev, unsigned int msec)
 {
         unsigned long flags;
 
-        spin_lock_irqsave(&events_lock, flags);
-        event_count++;
-        if (dev)
-                dev->power.wakeup_count++;
-
-        if (msec) {
-                unsigned long expires;
+        if (!dev)
+                return;
 
-                expires = jiffies + msecs_to_jiffies(msec);
-                if (!expires)
-                        expires = 1;
+        spin_lock_irqsave(&dev->power.lock, flags);
+        __pm_wakeup_event(dev->power.wakeup, msec);
+        spin_unlock_irqrestore(&dev->power.lock, flags);
+}
+EXPORT_SYMBOL_GPL(pm_wakeup_event);
 
-                if (!events_timer_expires
-                    || time_after(expires, events_timer_expires)) {
-                        if (!events_timer_expires)
-                                events_in_progress++;
+/**
+ * pm_wakeup_update_hit_counts - Update hit counts of all active wakeup sources.
+ */
+static void pm_wakeup_update_hit_counts(void)
+{
+        unsigned long flags;
+        struct wakeup_source *ws;
 
-                        mod_timer(&events_timer, expires);
-                        events_timer_expires = expires;
-                }
+        rcu_read_lock();
+        list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
+                spin_lock_irqsave(&ws->lock, flags);
+                if (ws->active)
+                        ws->hit_count++;
+                spin_unlock_irqrestore(&ws->lock, flags);
         }
-        spin_unlock_irqrestore(&events_lock, flags);
+        rcu_read_unlock();
 }
 
 /**
- * pm_check_wakeup_events - Check for new wakeup events.
+ * 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 to check if new wakeup events have been registered since
- * the old value was stored.  Check if the current number of wakeup events being
- * processed is zero.
+ * 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_check_wakeup_events(void)
+bool pm_wakeup_pending(void)
 {
         unsigned long flags;
-        bool ret = true;
+        bool ret = false;
 
         spin_lock_irqsave(&events_lock, flags);
         if (events_check_enabled) {
-                ret = (event_count == saved_event_count) && !events_in_progress;
-                events_check_enabled = ret;
+                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)
+                pm_wakeup_update_hit_counts();
         return ret;
 }
 
@@ -198,29 +614,25 @@ bool pm_check_wakeup_events(void)
  * Store the number of registered wakeup events at the address in @count.  Block
  * if the current number of wakeup events being processed is nonzero.
  *
- * Return false if the wait for the number of wakeup events being processed to
+ * Return 'false' if the wait for the number of wakeup events being processed to
  * drop down to zero has been interrupted by a signal (and the current number
- * of wakeup events being processed is still nonzero).  Otherwise return true.
+ * of wakeup events being processed is still nonzero).  Otherwise return 'true'.
  */
-bool pm_get_wakeup_count(unsigned long *count)
+bool pm_get_wakeup_count(unsigned int *count)
 {
-        bool ret;
-
-        spin_lock_irq(&events_lock);
-        if (capable(CAP_SYS_ADMIN))
-                events_check_enabled = false;
-
-        while (events_in_progress && !signal_pending(current)) {
-                spin_unlock_irq(&events_lock);
+        unsigned int cnt, inpr;
 
-                schedule_timeout_interruptible(msecs_to_jiffies(100));
-
-                spin_lock_irq(&events_lock);
+        for (;;) {
+                split_counters(&cnt, &inpr);
+                if (inpr == 0 || signal_pending(current))
+                        break;
+                pm_wakeup_update_hit_counts();
+                schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
         }
-        *count = event_count;
-        ret = !events_in_progress;
-        spin_unlock_irq(&events_lock);
-        return ret;
+
+        split_counters(&cnt, &inpr);
+        *count = cnt;
+        return !inpr;
 }
 
 /**
@@ -229,19 +641,106 @@ bool pm_get_wakeup_count(unsigned long *count)
  *
  * 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 to be used by pm_check_wakeup_events()
- * and return true.  Otherwise return false.
+ * 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 long count)
+bool pm_save_wakeup_count(unsigned int count)
 {
-        bool ret = false;
+        unsigned int cnt, inpr;
 
+        events_check_enabled = false;
         spin_lock_irq(&events_lock);
-        if (count == event_count && !events_in_progress) {
-                saved_event_count = count;
+        split_counters(&cnt, &inpr);
+        if (cnt == count && inpr == 0) {
+                saved_count = count;
                 events_check_enabled = true;
-                ret = true;
         }
         spin_unlock_irq(&events_lock);
+        if (!events_check_enabled)
+                pm_wakeup_update_hit_counts();
+        return events_check_enabled;
+}
+
+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;
+        int ret;
+
+        spin_lock_irqsave(&ws->lock, flags);
+
+        total_time = ws->total_time;
+        max_time = ws->max_time;
+        active_count = ws->active_count;
+        if (ws->active) {
+                active_time = ktime_sub(ktime_get(), ws->last_time);
+                total_time = ktime_add(total_time, active_time);
+                if (active_time.tv64 > max_time.tv64)
+                        max_time = active_time;
+        } else {
+                active_time = ktime_set(0, 0);
+        }
+
+        ret = seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t"
+                        "%lld\t\t%lld\t\t%lld\t\t%lld\n",
+                        ws->name, active_count, ws->event_count, ws->hit_count,
+                        ktime_to_ms(active_time), ktime_to_ms(total_time),
+                        ktime_to_ms(max_time), ktime_to_ms(ws->last_time));
+
+        spin_unlock_irqrestore(&ws->lock, flags);
+
         return ret;
 }
+
+/**
+ * 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;
+
+        seq_puts(m, "name\t\tactive_count\tevent_count\thit_count\t"
+                "active_since\ttotal_time\tmax_time\tlast_change\n");
+
+        rcu_read_lock();
+        list_for_each_entry_rcu(ws, &wakeup_sources, entry)
+                print_wakeup_source_stats(m, ws);
+        rcu_read_unlock();
+
+        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);