PM / Domains: Add device stop governor function (v4)

Add a function deciding whether or not devices should be stopped in
pm_genpd_runtime_suspend() depending on their PM QoS constraints
and stop/start timing values.  Make it possible to add information
used by this function to device objects.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@opensource.se>

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/base/power/domain_governor.c b/drivers/base/power/domain_governor.c
new file mode 100644
index 000000000000..97b21c10c496
--- /dev/null
+++ b/drivers/base/power/domain_governor.c
@@ -0,0 +1,33 @@
+/*
+ * drivers/base/power/domain_governor.c - Governors for device PM domains.
+ *
+ * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_qos.h>
+
+/**
+ * default_stop_ok - Default PM domain governor routine for stopping devices.
+ * @dev: Device to check.
+ */
+bool default_stop_ok(struct device *dev)
+{
+        struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
+
+        dev_dbg(dev, "%s()\n", __func__);
+
+        if (dev->power.max_time_suspended_ns < 0 || td->break_even_ns == 0)
+                return true;
+
+        return td->stop_latency_ns + td->start_latency_ns < td->break_even_ns
+                && td->break_even_ns < dev->power.max_time_suspended_ns;
+}
+
+struct dev_power_governor simple_qos_governor = {
+        .stop_ok = default_stop_ok,
+};