1 files changed, 127 insertions, 0 deletions

diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
new file mode 100644
index 000000000000..ca304046d9e2
--- /dev/null
+++ b/kernel/power/autosleep.c
@@ -0,0 +1,127 @@
+/*
+ * kernel/power/autosleep.c
+ *
+ * Opportunistic sleep support.
+ *
+ * Copyright (C) 2012 Rafael J. Wysocki <rjw@sisk.pl>
+ */
+
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/pm_wakeup.h>
+
+#include "power.h"
+
+static suspend_state_t autosleep_state;
+static struct workqueue_struct *autosleep_wq;
+/*
+ * Note: it is only safe to mutex_lock(&autosleep_lock) if a wakeup_source
+ * is active, otherwise a deadlock with try_to_suspend() is possible.
+ * Alternatively mutex_lock_interruptible() can be used.  This will then fail
+ * if an auto_sleep cycle tries to freeze processes.
+ */
+static DEFINE_MUTEX(autosleep_lock);
+static struct wakeup_source *autosleep_ws;
+
+static void try_to_suspend(struct work_struct *work)
+{
+        unsigned int initial_count, final_count;
+
+        if (!pm_get_wakeup_count(&initial_count, true))
+                goto out;
+
+        mutex_lock(&autosleep_lock);
+
+        if (!pm_save_wakeup_count(initial_count)) {
+                mutex_unlock(&autosleep_lock);
+                goto out;
+        }
+
+        if (autosleep_state == PM_SUSPEND_ON) {
+                mutex_unlock(&autosleep_lock);
+                return;
+        }
+        if (autosleep_state >= PM_SUSPEND_MAX)
+                hibernate();
+        else
+                pm_suspend(autosleep_state);
+
+        mutex_unlock(&autosleep_lock);
+
+        if (!pm_get_wakeup_count(&final_count, false))
+                goto out;
+
+        /*
+         * If the wakeup occured for an unknown reason, wait to prevent the
+         * system from trying to suspend and waking up in a tight loop.
+         */
+        if (final_count == initial_count)
+                schedule_timeout_uninterruptible(HZ / 2);
+
+ out:
+        queue_up_suspend_work();
+}
+
+static DECLARE_WORK(suspend_work, try_to_suspend);
+
+void queue_up_suspend_work(void)
+{
+        if (!work_pending(&suspend_work) && autosleep_state > PM_SUSPEND_ON)
+                queue_work(autosleep_wq, &suspend_work);
+}
+
+suspend_state_t pm_autosleep_state(void)
+{
+        return autosleep_state;
+}
+
+int pm_autosleep_lock(void)
+{
+        return mutex_lock_interruptible(&autosleep_lock);
+}
+
+void pm_autosleep_unlock(void)
+{
+        mutex_unlock(&autosleep_lock);
+}
+
+int pm_autosleep_set_state(suspend_state_t state)
+{
+
+#ifndef CONFIG_HIBERNATION
+        if (state >= PM_SUSPEND_MAX)
+                return -EINVAL;
+#endif
+
+        __pm_stay_awake(autosleep_ws);
+
+        mutex_lock(&autosleep_lock);
+
+        autosleep_state = state;
+
+        __pm_relax(autosleep_ws);
+
+        if (state > PM_SUSPEND_ON) {
+                pm_wakep_autosleep_enabled(true);
+                queue_up_suspend_work();
+        } else {
+                pm_wakep_autosleep_enabled(false);
+        }
+
+        mutex_unlock(&autosleep_lock);
+        return 0;
+}
+
+int __init pm_autosleep_init(void)
+{
+        autosleep_ws = wakeup_source_register("autosleep");
+        if (!autosleep_ws)
+                return -ENOMEM;
+
+        autosleep_wq = alloc_ordered_workqueue("autosleep", 0);
+        if (autosleep_wq)
+                return 0;
+
+        wakeup_source_unregister(autosleep_ws);
+        return -ENOMEM;
+}