v4.19.13 snapshot.
diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
new file mode 100644
index 0000000..41e83a7
--- /dev/null
+++ b/kernel/power/autosleep.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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) ||
+ system_state != SYSTEM_RUNNING) {
+ 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 (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;
+}