static int allocate_power()

in gov_power_allocator.c [383:503]

• 90 lines of code
• 12 McCabe index (conditional complexity)

static int allocate_power(struct thermal_zone_device *tz,
			  int control_temp)
{
	struct thermal_instance *instance;
	struct power_allocator_params *params = tz->governor_data;
	u32 *req_power, *max_power, *granted_power, *extra_actor_power;
	u32 *weighted_req_power;
	u32 total_req_power, max_allocatable_power, total_weighted_req_power;
	u32 total_granted_power, power_range;
	int i, num_actors, total_weight, ret = 0;
	int trip_max_desired_temperature = params->trip_max_desired_temperature;

	mutex_lock(&tz->lock);

	num_actors = 0;
	total_weight = 0;
	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
		if ((instance->trip == trip_max_desired_temperature) &&
		    cdev_is_power_actor(instance->cdev)) {
			num_actors++;
			total_weight += instance->weight;
		}
	}

	if (!num_actors) {
		ret = -ENODEV;
		goto unlock;
	}

	/*
	 * We need to allocate five arrays of the same size:
	 * req_power, max_power, granted_power, extra_actor_power and
	 * weighted_req_power.  They are going to be needed until this
	 * function returns.  Allocate them all in one go to simplify
	 * the allocation and deallocation logic.
	 */
	BUILD_BUG_ON(sizeof(*req_power) != sizeof(*max_power));
	BUILD_BUG_ON(sizeof(*req_power) != sizeof(*granted_power));
	BUILD_BUG_ON(sizeof(*req_power) != sizeof(*extra_actor_power));
	BUILD_BUG_ON(sizeof(*req_power) != sizeof(*weighted_req_power));
	req_power = kcalloc(num_actors * 5, sizeof(*req_power), GFP_KERNEL);
	if (!req_power) {
		ret = -ENOMEM;
		goto unlock;
	}

	max_power = &req_power[num_actors];
	granted_power = &req_power[2 * num_actors];
	extra_actor_power = &req_power[3 * num_actors];
	weighted_req_power = &req_power[4 * num_actors];

	i = 0;
	total_weighted_req_power = 0;
	total_req_power = 0;
	max_allocatable_power = 0;

	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
		int weight;
		struct thermal_cooling_device *cdev = instance->cdev;

		if (instance->trip != trip_max_desired_temperature)
			continue;

		if (!cdev_is_power_actor(cdev))
			continue;

		if (cdev->ops->get_requested_power(cdev, &req_power[i]))
			continue;

		if (!total_weight)
			weight = 1 << FRAC_BITS;
		else
			weight = instance->weight;

		weighted_req_power[i] = frac_to_int(weight * req_power[i]);

		if (cdev->ops->state2power(cdev, instance->lower,
					   &max_power[i]))
			continue;

		total_req_power += req_power[i];
		max_allocatable_power += max_power[i];
		total_weighted_req_power += weighted_req_power[i];

		i++;
	}

	power_range = pid_controller(tz, control_temp, max_allocatable_power);

	divvy_up_power(weighted_req_power, max_power, num_actors,
		       total_weighted_req_power, power_range, granted_power,
		       extra_actor_power);

	total_granted_power = 0;
	i = 0;
	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
		if (instance->trip != trip_max_desired_temperature)
			continue;

		if (!cdev_is_power_actor(instance->cdev))
			continue;

		power_actor_set_power(instance->cdev, instance,
				      granted_power[i]);
		total_granted_power += granted_power[i];

		i++;
	}

	trace_thermal_power_allocator(tz, req_power, total_req_power,
				      granted_power, total_granted_power,
				      num_actors, power_range,
				      max_allocatable_power, tz->temperature,
				      control_temp - tz->temperature);

	kfree(req_power);
unlock:
	mutex_unlock(&tz->lock);

	return ret;
}