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Diffstat (limited to 'drivers/base/power/wakeup.c')
-rw-r--r--drivers/base/power/wakeup.c109
1 files changed, 76 insertions, 33 deletions
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 8ec406d8f54..4573c83df6d 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -24,12 +24,26 @@
*/
bool events_check_enabled;
-/* The counter of registered wakeup events. */
-static atomic_t event_count = ATOMIC_INIT(0);
-/* A preserved old value of event_count. */
+/*
+ * 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;
-/* The counter of wakeup events being processed. */
-static atomic_t events_in_progress = ATOMIC_INIT(0);
static DEFINE_SPINLOCK(events_lock);
@@ -228,6 +242,35 @@ int device_wakeup_disable(struct device *dev)
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)) {
+ 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.
@@ -307,7 +350,8 @@ static void wakeup_source_activate(struct wakeup_source *ws)
ws->timer_expires = jiffies;
ws->last_time = ktime_get();
- atomic_inc(&events_in_progress);
+ /* Increment the counter of events in progress. */
+ atomic_inc(&combined_event_count);
}
/**
@@ -394,14 +438,10 @@ static void wakeup_source_deactivate(struct wakeup_source *ws)
del_timer(&ws->timer);
/*
- * event_count has to be incremented before events_in_progress is
- * modified, so that the callers of pm_check_wakeup_events() and
- * pm_save_wakeup_count() don't see the old value of event_count and
- * events_in_progress equal to zero at the same time.
+ * Increment the counter of registered wakeup events and decrement the
+ * couter of wakeup events in progress simultaneously.
*/
- atomic_inc(&event_count);
- smp_mb__before_atomic_dec();
- atomic_dec(&events_in_progress);
+ atomic_add(MAX_IN_PROGRESS, &combined_event_count);
}
/**
@@ -556,8 +596,10 @@ bool pm_wakeup_pending(void)
spin_lock_irqsave(&events_lock, flags);
if (events_check_enabled) {
- ret = ((unsigned int)atomic_read(&event_count) != saved_count)
- || atomic_read(&events_in_progress);
+ unsigned int cnt, inpr;
+
+ split_counters(&cnt, &inpr);
+ ret = (cnt != saved_count || inpr > 0);
events_check_enabled = !ret;
}
spin_unlock_irqrestore(&events_lock, flags);
@@ -573,25 +615,25 @@ bool pm_wakeup_pending(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 int *count)
{
- bool ret;
-
- if (capable(CAP_SYS_ADMIN))
- events_check_enabled = false;
+ unsigned int cnt, inpr;
- while (atomic_read(&events_in_progress) && !signal_pending(current)) {
+ for (;;) {
+ split_counters(&cnt, &inpr);
+ if (inpr == 0 || signal_pending(current))
+ break;
pm_wakeup_update_hit_counts();
schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
}
- ret = !atomic_read(&events_in_progress);
- *count = atomic_read(&event_count);
- return ret;
+ split_counters(&cnt, &inpr);
+ *count = cnt;
+ return !inpr;
}
/**
@@ -600,24 +642,25 @@ bool pm_get_wakeup_count(unsigned int *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 int count)
{
- bool ret = false;
+ unsigned int cnt, inpr;
+ events_check_enabled = false;
spin_lock_irq(&events_lock);
- if (count == (unsigned int)atomic_read(&event_count)
- && !atomic_read(&events_in_progress)) {
+ split_counters(&cnt, &inpr);
+ if (cnt == count && inpr == 0) {
saved_count = count;
events_check_enabled = true;
- ret = true;
}
spin_unlock_irq(&events_lock);
- if (!ret)
+ if (!events_check_enabled)
pm_wakeup_update_hit_counts();
- return ret;
+ return events_check_enabled;
}
static struct dentry *wakeup_sources_stats_dentry;