PM / Domains: Add default power off governor function (v4)

Add a function deciding whether or not a given PM domain should
be powered off on the basis of the PM QoS constraints of devices
belonging to it and their PM QoS timing data.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index f6745c2..cc1a245 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -61,8 +61,13 @@
 	bool suspend_power_off;	/* Power status before system suspend */
 	bool dev_irq_safe;	/* Device callbacks are IRQ-safe */
 	int (*power_off)(struct generic_pm_domain *domain);
+	s64 power_off_latency_ns;
 	int (*power_on)(struct generic_pm_domain *domain);
+	s64 power_on_latency_ns;
 	struct gpd_dev_ops dev_ops;
+	s64 break_even_ns;	/* Power break even for the entire domain. */
+	s64 max_off_time_ns;	/* Maximum allowed "suspended" time. */
+	ktime_t power_off_time;
 };
 
 static inline struct generic_pm_domain *pd_to_genpd(struct dev_pm_domain *pd)
@@ -80,6 +85,8 @@
 struct gpd_timing_data {
 	s64 stop_latency_ns;
 	s64 start_latency_ns;
+	s64 save_state_latency_ns;
+	s64 restore_state_latency_ns;
 	s64 break_even_ns;
 };