thermal: gov_power_allocator: Support new update callback of weights

When the thermal instance's weight is updated from the sysfs the governor
update_tz() callback is triggered. Implement proper reaction to this
event in the IPA, which would save CPU cycles spent in throttle().
This will speed-up the main throttle() IPA function and clean it up
a bit.

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: lukaszluba-arm

drivers/thermal/gov_power_allocator.c

@@ -77,6 +77,7 @@ struct power_actor {
  *			@trip_switch_on should be NULL.
  * @trip_max:		last passive trip point of the thermal zone. The
  *			temperature we are controlling for.
+ * @total_weight:	Sum of all thermal instances weights
  * @num_actors:		number of cooling devices supporting IPA callbacks
  * @buffer_size:	internal buffer size, to avoid runtime re-calculation
  * @power:		buffer for all power actors internal power information
@@ -88,6 +89,7 @@ struct power_allocator_params {
 	u32 sustainable_power;
 	const struct thermal_trip *trip_switch_on;
 	const struct thermal_trip *trip_max;
+	int total_weight;
 	unsigned int num_actors;
 	unsigned int buffer_size;
 	struct power_actor *power;
@@ -405,16 +407,11 @@ static int allocate_power(struct thermal_zone_device *tz, int control_temp)
 	u32 total_granted_power = 0;
 	u32 total_req_power = 0;
 	u32 power_range, weight;
-	int total_weight = 0;
 	int i = 0, ret;
 
 	if (!num_actors)
 		return -ENODEV;
 
-	list_for_each_entry(instance, &tz->thermal_instances, tz_node)
-		if (power_actor_is_valid(params, instance))
-			total_weight += instance->weight;
-
 	/* Clean all buffers for new power estimations */
 	memset(power, 0, params->buffer_size);
 
@@ -430,7 +427,7 @@ static int allocate_power(struct thermal_zone_device *tz, int control_temp)
 		if (ret)
 			continue;
 
-		if (!total_weight)
+		if (!params->total_weight)
 			weight = 1 << FRAC_BITS;
 		else
 			weight = instance->weight;
@@ -651,6 +648,12 @@ static void power_allocator_update_tz(struct thermal_zone_device *tz,
 
 		allocate_actors_buffer(params, num_actors);
 		break;
+	case THERMAL_INSTANCE_WEIGHT_CHANGED:
+		params->total_weight = 0;
+		list_for_each_entry(instance, &tz->thermal_instances, tz_node)
+			if (power_actor_is_valid(params, instance))
+				params->total_weight += instance->weight;
+		break;
 	default:
 		break;
 	}