1 files changed, 156 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..51527ee92d10
--- /dev/null
+++ b/drivers/base/power/domain_governor.c
@@ -0,0 +1,156 @@
+/*
+ * 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>
+#include <linux/hrtimer.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;
+}
+
+/**
+ * default_power_down_ok - Default generic PM domain power off governor routine.
+ * @pd: PM domain to check.
+ *
+ * This routine must be executed under the PM domain's lock.
+ */
+static bool default_power_down_ok(struct dev_pm_domain *pd)
+{
+	struct generic_pm_domain *genpd = pd_to_genpd(pd);
+	struct gpd_link *link;
+	struct pm_domain_data *pdd;
+	s64 min_dev_off_time_ns;
+	s64 off_on_time_ns;
+	ktime_t time_now = ktime_get();
+
+	off_on_time_ns = genpd->power_off_latency_ns +
+				genpd->power_on_latency_ns;
+	/*
+	 * It doesn't make sense to remove power from the domain if saving
+	 * the state of all devices in it and the power off/power on operations
+	 * take too much time.
+	 *
+	 * All devices in this domain have been stopped already at this point.
+	 */
+	list_for_each_entry(pdd, &genpd->dev_list, list_node) {
+		if (pdd->dev->driver)
+			off_on_time_ns +=
+				to_gpd_data(pdd)->td.save_state_latency_ns;
+	}
+
+	/*
+	 * Check if subdomains can be off for enough time.
+	 *
+	 * All subdomains have been powered off already at this point.
+	 */
+	list_for_each_entry(link, &genpd->master_links, master_node) {
+		struct generic_pm_domain *sd = link->slave;
+		s64 sd_max_off_ns = sd->max_off_time_ns;
+
+		if (sd_max_off_ns < 0)
+			continue;
+
+		sd_max_off_ns -= ktime_to_ns(ktime_sub(time_now,
+						       sd->power_off_time));
+		/*
+		 * Check if the subdomain is allowed to be off long enough for
+		 * the current domain to turn off and on (that's how much time
+		 * it will have to wait worst case).
+		 */
+		if (sd_max_off_ns <= off_on_time_ns)
+			return false;
+	}
+
+	/*
+	 * Check if the devices in the domain can be off enough time.
+	 */
+	min_dev_off_time_ns = -1;
+	list_for_each_entry(pdd, &genpd->dev_list, list_node) {
+		struct gpd_timing_data *td;
+		struct device *dev = pdd->dev;
+		s64 dev_off_time_ns;
+
+		if (!dev->driver || dev->power.max_time_suspended_ns < 0)
+			continue;
+
+		td = &to_gpd_data(pdd)->td;
+		dev_off_time_ns = dev->power.max_time_suspended_ns -
+			(td->start_latency_ns + td->restore_state_latency_ns +
+				ktime_to_ns(ktime_sub(time_now,
+						dev->power.suspend_time)));
+		if (dev_off_time_ns <= off_on_time_ns)
+			return false;
+
+		if (min_dev_off_time_ns > dev_off_time_ns
+		    || min_dev_off_time_ns < 0)
+			min_dev_off_time_ns = dev_off_time_ns;
+	}
+
+	if (min_dev_off_time_ns < 0) {
+		/*
+		 * There are no latency constraints, so the domain can spend
+		 * arbitrary time in the "off" state.
+		 */
+		genpd->max_off_time_ns = -1;
+		return true;
+	}
+
+	/*
+	 * The difference between the computed minimum delta and the time needed
+	 * to turn the domain on is the maximum theoretical time this domain can
+	 * spend in the "off" state.
+	 */
+	min_dev_off_time_ns -= genpd->power_on_latency_ns;
+
+	/*
+	 * If the difference between the computed minimum delta and the time
+	 * needed to turn the domain off and back on on is smaller than the
+	 * domain's power break even time, removing power from the domain is not
+	 * worth it.
+	 */
+	if (genpd->break_even_ns >
+	    min_dev_off_time_ns - genpd->power_off_latency_ns)
+		return false;
+
+	genpd->max_off_time_ns = min_dev_off_time_ns;
+	return true;
+}
+
+struct dev_power_governor simple_qos_governor = {
+	.stop_ok = default_stop_ok,
+	.power_down_ok = default_power_down_ok,
+};
+
+static bool always_on_power_down_ok(struct dev_pm_domain *domain)
+{
+	return false;
+}
+
+/**
+ * pm_genpd_gov_always_on - A governor implementing an always-on policy
+ */
+struct dev_power_governor pm_domain_always_on_gov = {
+	.power_down_ok = always_on_power_down_ok,
+	.stop_ok = default_stop_ok,
+};