int trip_max_desired_temperature;
};
+/**
+ * estimate_sustainable_power() - Estimate the sustainable power of a thermal zone
+ * @tz: thermal zone we are operating in
+ *
+ * For thermal zones that don't provide a sustainable_power in their
+ * thermal_zone_params, estimate one. Calculate it using the minimum
+ * power of all the cooling devices as that gives a valid value that
+ * can give some degree of functionality. For optimal performance of
+ * this governor, provide a sustainable_power in the thermal zone's
+ * thermal_zone_params.
+ */
+static u32 estimate_sustainable_power(struct thermal_zone_device *tz)
+{
+ u32 sustainable_power = 0;
+ struct thermal_instance *instance;
+ struct power_allocator_params *params = tz->governor_data;
+
+ list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
+ struct thermal_cooling_device *cdev = instance->cdev;
+ u32 min_power;
+
+ if (instance->trip != params->trip_max_desired_temperature)
+ continue;
+
+ if (power_actor_get_min_power(cdev, tz, &min_power))
+ continue;
+
+ sustainable_power += min_power;
+ }
+
+ return sustainable_power;
+}
+
+/**
+ * estimate_pid_constants() - Estimate the constants for the PID controller
+ * @tz: thermal zone for which to estimate the constants
+ * @sustainable_power: sustainable power for the thermal zone
+ * @trip_switch_on: trip point number for the switch on temperature
+ * @control_temp: target temperature for the power allocator governor
+ * @force: whether to force the update of the constants
+ *
+ * This function is used to update the estimation of the PID
+ * controller constants in struct thermal_zone_parameters.
+ * Sustainable power is provided in case it was estimated. The
+ * estimated sustainable_power should not be stored in the
+ * thermal_zone_parameters so it has to be passed explicitly to this
+ * function.
+ *
+ * If @force is not set, the values in the thermal zone's parameters
+ * are preserved if they are not zero. If @force is set, the values
+ * in thermal zone's parameters are overwritten.
+ */
+static void estimate_pid_constants(struct thermal_zone_device *tz,
+ u32 sustainable_power, int trip_switch_on,
+ int control_temp, bool force)
+{
+ int ret;
+ int switch_on_temp;
+ u32 temperature_threshold;
+
+ ret = tz->ops->get_trip_temp(tz, trip_switch_on, &switch_on_temp);
+ if (ret)
+ switch_on_temp = 0;
+
+ temperature_threshold = control_temp - switch_on_temp;
+
+ if (!tz->tzp->k_po || force)
+ tz->tzp->k_po = int_to_frac(sustainable_power) /
+ temperature_threshold;
+
+ if (!tz->tzp->k_pu || force)
+ tz->tzp->k_pu = int_to_frac(2 * sustainable_power) /
+ temperature_threshold;
+
+ if (!tz->tzp->k_i || force)
+ tz->tzp->k_i = int_to_frac(10) / 1000;
+ /*
+ * The default for k_d and integral_cutoff is 0, so we can
+ * leave them as they are.
+ */
+}
+
/**
* pid_controller() - PID controller
* @tz: thermal zone we are operating in
{
s64 p, i, d, power_range;
s32 err, max_power_frac;
+ u32 sustainable_power;
struct power_allocator_params *params = tz->governor_data;
max_power_frac = int_to_frac(max_allocatable_power);
+ if (tz->tzp->sustainable_power) {
+ sustainable_power = tz->tzp->sustainable_power;
+ } else {
+ sustainable_power = estimate_sustainable_power(tz);
+ estimate_pid_constants(tz, sustainable_power,
+ params->trip_switch_on, control_temp,
+ true);
+ }
+
err = control_temp - current_temp;
err = int_to_frac(err);
power_range = p + i + d;
/* feed-forward the known sustainable dissipatable power */
- power_range = tz->tzp->sustainable_power + frac_to_int(power_range);
+ power_range = sustainable_power + frac_to_int(power_range);
power_range = clamp(power_range, (s64)0, (s64)max_allocatable_power);
{
int ret;
struct power_allocator_params *params;
- int switch_on_temp, control_temp;
- u32 temperature_threshold;
+ int control_temp;
- if (!tz->tzp || !tz->tzp->sustainable_power) {
- dev_err(&tz->device,
- "power_allocator: missing sustainable_power\n");
+ if (!tz->tzp)
return -EINVAL;
- }
params = kzalloc(sizeof(*params), GFP_KERNEL);
if (!params)
return -ENOMEM;
+ if (!tz->tzp->sustainable_power)
+ dev_warn(&tz->device, "power_allocator: sustainable_power will be estimated\n");
+
ret = get_governor_trips(tz, params);
if (ret) {
dev_err(&tz->device,
goto free;
}
- ret = tz->ops->get_trip_temp(tz, params->trip_switch_on,
- &switch_on_temp);
- if (ret)
- goto free;
-
ret = tz->ops->get_trip_temp(tz, params->trip_max_desired_temperature,
&control_temp);
if (ret)
goto free;
- temperature_threshold = control_temp - switch_on_temp;
-
- tz->tzp->k_po = tz->tzp->k_po ?:
- int_to_frac(tz->tzp->sustainable_power) / temperature_threshold;
- tz->tzp->k_pu = tz->tzp->k_pu ?:
- int_to_frac(2 * tz->tzp->sustainable_power) /
- temperature_threshold;
- tz->tzp->k_i = tz->tzp->k_i ?: int_to_frac(10) / 1000;
- /*
- * The default for k_d and integral_cutoff is 0, so we can
- * leave them as they are.
- */
-
+ estimate_pid_constants(tz, tz->tzp->sustainable_power,
+ params->trip_switch_on, control_temp, false);
reset_pid_controller(params);
tz->governor_data = params;