thermal: introduce the Power Allocator governor

The power allocator governor is a thermal governor that controls system
and device power allocation to control temperature.  Conceptually, the
implementation divides the sustainable power of a thermal zone among
all the heat sources in that zone.

This governor relies on "power actors", entities that represent heat
sources.  They can report current and maximum power consumption and
can set a given maximum power consumption, usually via a cooling
device.

The governor uses a Proportional Integral Derivative (PID) controller
driven by the temperature of the thermal zone.  The output of the
controller is a power budget that is then allocated to each power
actor that can have bearing on the temperature we are trying to
control.  It decides how much power to give each cooling device based
on the performance they are requesting.  The PID controller ensures
that the total power budget does not exceed the control temperature.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 263628b0e862..b389bc2ec0fa 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1616,7 +1616,7 @@ static void remove_trip_attrs(struct thermal_zone_device *tz)
 struct thermal_zone_device *thermal_zone_device_register(const char *type,
 	int trips, int mask, void *devdata,
 	struct thermal_zone_device_ops *ops,
-	const struct thermal_zone_params *tzp,
+	struct thermal_zone_params *tzp,
 	int passive_delay, int polling_delay)
 {
 	struct thermal_zone_device *tz;
@@ -1968,7 +1968,11 @@ static int __init thermal_register_governors(void)
 	if (result)
 		return result;
 
-	return thermal_gov_user_space_register();
+	result = thermal_gov_user_space_register();
+	if (result)
+		return result;
+
+	return thermal_gov_power_allocator_register();
 }
 
 static void thermal_unregister_governors(void)
@@ -1977,6 +1981,7 @@ static void thermal_unregister_governors(void)
 	thermal_gov_fair_share_unregister();
 	thermal_gov_bang_bang_unregister();
 	thermal_gov_user_space_unregister();
+	thermal_gov_power_allocator_unregister();
 }
 
 static int __init thermal_init(void)