#include "thermal_core.h"
+#define INVALID_TRIP -1
+
#define FRAC_BITS 10
#define int_to_frac(x) ((x) << FRAC_BITS)
#define frac_to_int(x) ((x) >> FRAC_BITS)
/**
* struct power_allocator_params - parameters for the power allocator governor
+ * @allocated_tzp: whether we have allocated tzp for this thermal zone and
+ * it needs to be freed on unbind
* @err_integral: accumulated error in the PID controller.
* @prev_err: error in the previous iteration of the PID controller.
* Used to calculate the derivative term.
* @trip_switch_on: first passive trip point of the thermal zone. The
* governor switches on when this trip point is crossed.
+ * If the thermal zone only has one passive trip point,
+ * @trip_switch_on should be INVALID_TRIP.
* @trip_max_desired_temperature: last passive trip point of the thermal
* zone. The temperature we are
* controlling for.
*/
struct power_allocator_params {
+ bool allocated_tzp;
s64 err_integral;
s32 prev_err;
int trip_switch_on;
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
* Return: The power budget for the next period.
*/
static u32 pid_controller(struct thermal_zone_device *tz,
- unsigned long current_temp,
- unsigned long control_temp,
+ int current_temp,
+ int control_temp,
u32 max_allocatable_power)
{
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);
- err = ((s32)control_temp - (s32)current_temp);
+ 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);
/* Calculate the proportional term */
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);
}
static int allocate_power(struct thermal_zone_device *tz,
- unsigned long current_temp,
- unsigned long control_temp)
+ int current_temp,
+ int control_temp)
{
struct thermal_instance *instance;
struct power_allocator_params *params = tz->governor_data;
granted_power, total_granted_power,
num_actors, power_range,
max_allocatable_power, current_temp,
- (s32)control_temp - (s32)current_temp);
+ control_temp - current_temp);
kfree(req_power);
unlock:
return ret;
}
-static int get_governor_trips(struct thermal_zone_device *tz,
- struct power_allocator_params *params)
+/**
+ * get_governor_trips() - get the number of the two trip points that are key for this governor
+ * @tz: thermal zone to operate on
+ * @params: pointer to private data for this governor
+ *
+ * The power allocator governor works optimally with two trips points:
+ * a "switch on" trip point and a "maximum desired temperature". These
+ * are defined as the first and last passive trip points.
+ *
+ * If there is only one trip point, then that's considered to be the
+ * "maximum desired temperature" trip point and the governor is always
+ * on. If there are no passive or active trip points, then the
+ * governor won't do anything. In fact, its throttle function
+ * won't be called at all.
+ */
+static void get_governor_trips(struct thermal_zone_device *tz,
+ struct power_allocator_params *params)
{
- int i, ret, last_passive;
+ int i, last_active, last_passive;
bool found_first_passive;
found_first_passive = false;
- last_passive = -1;
- ret = -EINVAL;
+ last_active = INVALID_TRIP;
+ last_passive = INVALID_TRIP;
for (i = 0; i < tz->trips; i++) {
enum thermal_trip_type type;
+ int ret;
ret = tz->ops->get_trip_type(tz, i, &type);
- if (ret)
- return ret;
+ if (ret) {
+ dev_warn(&tz->device,
+ "Failed to get trip point %d type: %d\n", i,
+ ret);
+ continue;
+ }
- if (!found_first_passive) {
- if (type == THERMAL_TRIP_PASSIVE) {
+ if (type == THERMAL_TRIP_PASSIVE) {
+ if (!found_first_passive) {
params->trip_switch_on = i;
found_first_passive = true;
+ } else {
+ last_passive = i;
}
- } else if (type == THERMAL_TRIP_PASSIVE) {
- last_passive = i;
+ } else if (type == THERMAL_TRIP_ACTIVE) {
+ last_active = i;
} else {
break;
}
}
- if (last_passive != -1) {
+ if (last_passive != INVALID_TRIP) {
params->trip_max_desired_temperature = last_passive;
- ret = 0;
+ } else if (found_first_passive) {
+ params->trip_max_desired_temperature = params->trip_switch_on;
+ params->trip_switch_on = INVALID_TRIP;
} else {
- ret = -EINVAL;
+ params->trip_switch_on = INVALID_TRIP;
+ params->trip_max_desired_temperature = last_active;
}
-
- return ret;
}
static void reset_pid_controller(struct power_allocator_params *params)
* power_allocator_bind() - bind the power_allocator governor to a thermal zone
* @tz: thermal zone to bind it to
*
- * Check that the thermal zone is valid for this governor, that is, it
- * has two thermal trips. If so, initialize the PID controller
- * parameters and bind it to the thermal zone.
+ * Initialize the PID controller parameters and bind it to the thermal
+ * zone.
*
- * Return: 0 on success, -EINVAL if the trips were invalid or -ENOMEM
- * if we ran out of memory.
+ * Return: 0 on success, or -ENOMEM if we ran out of memory.
*/
static int power_allocator_bind(struct thermal_zone_device *tz)
{
int ret;
struct power_allocator_params *params;
- unsigned long switch_on_temp, control_temp;
- u32 temperature_threshold;
-
- if (!tz->tzp || !tz->tzp->sustainable_power) {
- dev_err(&tz->device,
- "power_allocator: missing sustainable_power\n");
- return -EINVAL;
- }
+ int control_temp;
params = kzalloc(sizeof(*params), GFP_KERNEL);
if (!params)
return -ENOMEM;
- ret = get_governor_trips(tz, params);
- if (ret) {
- dev_err(&tz->device,
- "thermal zone %s has wrong trip setup for power allocator\n",
- tz->type);
- goto free;
+ if (!tz->tzp) {
+ tz->tzp = kzalloc(sizeof(*tz->tzp), GFP_KERNEL);
+ if (!tz->tzp) {
+ ret = -ENOMEM;
+ goto free_params;
+ }
+
+ params->allocated_tzp = true;
}
- ret = tz->ops->get_trip_temp(tz, params->trip_switch_on,
- &switch_on_temp);
- if (ret)
- goto free;
+ if (!tz->tzp->sustainable_power)
+ dev_warn(&tz->device, "power_allocator: sustainable_power will be estimated\n");
- 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;
+ get_governor_trips(tz, params);
- 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.
- */
+ if (tz->trips > 0) {
+ ret = tz->ops->get_trip_temp(tz,
+ params->trip_max_desired_temperature,
+ &control_temp);
+ if (!ret)
+ estimate_pid_constants(tz, tz->tzp->sustainable_power,
+ params->trip_switch_on,
+ control_temp, false);
+ }
reset_pid_controller(params);
return 0;
-free:
+free_params:
kfree(params);
+
return ret;
}
static void power_allocator_unbind(struct thermal_zone_device *tz)
{
+ struct power_allocator_params *params = tz->governor_data;
+
dev_dbg(&tz->device, "Unbinding from thermal zone %d\n", tz->id);
+
+ if (params->allocated_tzp) {
+ kfree(tz->tzp);
+ tz->tzp = NULL;
+ }
+
kfree(tz->governor_data);
tz->governor_data = NULL;
}
static int power_allocator_throttle(struct thermal_zone_device *tz, int trip)
{
int ret;
- unsigned long switch_on_temp, control_temp, current_temp;
+ int switch_on_temp, control_temp, current_temp;
struct power_allocator_params *params = tz->governor_data;
/*
ret = tz->ops->get_trip_temp(tz, params->trip_switch_on,
&switch_on_temp);
- if (ret) {
- dev_warn(&tz->device,
- "Failed to get switch on temperature: %d\n", ret);
- return ret;
- }
-
- if (current_temp < switch_on_temp) {
+ if (!ret && (current_temp < switch_on_temp)) {
tz->passive = 0;
reset_pid_controller(params);
allow_maximum_power(tz);
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