v4.19.13 snapshot.
diff --git a/drivers/thermal/power_allocator.c b/drivers/thermal/power_allocator.c
new file mode 100644
index 0000000..3055f9a
--- /dev/null
+++ b/drivers/thermal/power_allocator.c
@@ -0,0 +1,663 @@
+/*
+ * A power allocator to manage temperature
+ *
+ * Copyright (C) 2014 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) "Power allocator: " fmt
+
+#include <linux/rculist.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/thermal_power_allocator.h>
+
+#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)
+
+/**
+ * mul_frac() - multiply two fixed-point numbers
+ * @x: first multiplicand
+ * @y: second multiplicand
+ *
+ * Return: the result of multiplying two fixed-point numbers. The
+ * result is also a fixed-point number.
+ */
+static inline s64 mul_frac(s64 x, s64 y)
+{
+ return (x * y) >> FRAC_BITS;
+}
+
+/**
+ * div_frac() - divide two fixed-point numbers
+ * @x: the dividend
+ * @y: the divisor
+ *
+ * Return: the result of dividing two fixed-point numbers. The
+ * result is also a fixed-point number.
+ */
+static inline s64 div_frac(s64 x, s64 y)
+{
+ return div_s64(x << FRAC_BITS, y);
+}
+
+/**
+ * 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;
+ /*
+ * estimate_pid_constants() tries to find appropriate default
+ * values for thermal zones that don't provide them. If a
+ * system integrator has configured a thermal zone with two
+ * passive trip points at the same temperature, that person
+ * hasn't put any effort to set up the thermal zone properly
+ * so just give up.
+ */
+ if (!temperature_threshold)
+ return;
+
+ 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
+ * @control_temp: the target temperature in millicelsius
+ * @max_allocatable_power: maximum allocatable power for this thermal zone
+ *
+ * This PID controller increases the available power budget so that the
+ * temperature of the thermal zone gets as close as possible to
+ * @control_temp and limits the power if it exceeds it. k_po is the
+ * proportional term when we are overshooting, k_pu is the
+ * proportional term when we are undershooting. integral_cutoff is a
+ * threshold below which we stop accumulating the error. The
+ * accumulated error is only valid if the requested power will make
+ * the system warmer. If the system is mostly idle, there's no point
+ * in accumulating positive error.
+ *
+ * Return: The power budget for the next period.
+ */
+static u32 pid_controller(struct thermal_zone_device *tz,
+ 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);
+
+ 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 - tz->temperature;
+ err = int_to_frac(err);
+
+ /* Calculate the proportional term */
+ p = mul_frac(err < 0 ? tz->tzp->k_po : tz->tzp->k_pu, err);
+
+ /*
+ * Calculate the integral term
+ *
+ * if the error is less than cut off allow integration (but
+ * the integral is limited to max power)
+ */
+ i = mul_frac(tz->tzp->k_i, params->err_integral);
+
+ if (err < int_to_frac(tz->tzp->integral_cutoff)) {
+ s64 i_next = i + mul_frac(tz->tzp->k_i, err);
+
+ if (abs(i_next) < max_power_frac) {
+ i = i_next;
+ params->err_integral += err;
+ }
+ }
+
+ /*
+ * Calculate the derivative term
+ *
+ * We do err - prev_err, so with a positive k_d, a decreasing
+ * error (i.e. driving closer to the line) results in less
+ * power being applied, slowing down the controller)
+ */
+ d = mul_frac(tz->tzp->k_d, err - params->prev_err);
+ d = div_frac(d, tz->passive_delay);
+ params->prev_err = err;
+
+ power_range = p + i + d;
+
+ /* feed-forward the known sustainable dissipatable power */
+ power_range = sustainable_power + frac_to_int(power_range);
+
+ power_range = clamp(power_range, (s64)0, (s64)max_allocatable_power);
+
+ trace_thermal_power_allocator_pid(tz, frac_to_int(err),
+ frac_to_int(params->err_integral),
+ frac_to_int(p), frac_to_int(i),
+ frac_to_int(d), power_range);
+
+ return power_range;
+}
+
+/**
+ * divvy_up_power() - divvy the allocated power between the actors
+ * @req_power: each actor's requested power
+ * @max_power: each actor's maximum available power
+ * @num_actors: size of the @req_power, @max_power and @granted_power's array
+ * @total_req_power: sum of @req_power
+ * @power_range: total allocated power
+ * @granted_power: output array: each actor's granted power
+ * @extra_actor_power: an appropriately sized array to be used in the
+ * function as temporary storage of the extra power given
+ * to the actors
+ *
+ * This function divides the total allocated power (@power_range)
+ * fairly between the actors. It first tries to give each actor a
+ * share of the @power_range according to how much power it requested
+ * compared to the rest of the actors. For example, if only one actor
+ * requests power, then it receives all the @power_range. If
+ * three actors each requests 1mW, each receives a third of the
+ * @power_range.
+ *
+ * If any actor received more than their maximum power, then that
+ * surplus is re-divvied among the actors based on how far they are
+ * from their respective maximums.
+ *
+ * Granted power for each actor is written to @granted_power, which
+ * should've been allocated by the calling function.
+ */
+static void divvy_up_power(u32 *req_power, u32 *max_power, int num_actors,
+ u32 total_req_power, u32 power_range,
+ u32 *granted_power, u32 *extra_actor_power)
+{
+ u32 extra_power, capped_extra_power;
+ int i;
+
+ /*
+ * Prevent division by 0 if none of the actors request power.
+ */
+ if (!total_req_power)
+ total_req_power = 1;
+
+ capped_extra_power = 0;
+ extra_power = 0;
+ for (i = 0; i < num_actors; i++) {
+ u64 req_range = (u64)req_power[i] * power_range;
+
+ granted_power[i] = DIV_ROUND_CLOSEST_ULL(req_range,
+ total_req_power);
+
+ if (granted_power[i] > max_power[i]) {
+ extra_power += granted_power[i] - max_power[i];
+ granted_power[i] = max_power[i];
+ }
+
+ extra_actor_power[i] = max_power[i] - granted_power[i];
+ capped_extra_power += extra_actor_power[i];
+ }
+
+ if (!extra_power)
+ return;
+
+ /*
+ * Re-divvy the reclaimed extra among actors based on
+ * how far they are from the max
+ */
+ extra_power = min(extra_power, capped_extra_power);
+ if (capped_extra_power > 0)
+ for (i = 0; i < num_actors; i++)
+ granted_power[i] += (extra_actor_power[i] *
+ extra_power) / capped_extra_power;
+}
+
+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, tz, &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 (power_actor_get_max_power(cdev, tz, &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;
+}
+
+/**
+ * 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, last_active, last_passive;
+ bool found_first_passive;
+
+ found_first_passive = false;
+ 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) {
+ dev_warn(&tz->device,
+ "Failed to get trip point %d type: %d\n", i,
+ ret);
+ continue;
+ }
+
+ 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_ACTIVE) {
+ last_active = i;
+ } else {
+ break;
+ }
+ }
+
+ if (last_passive != INVALID_TRIP) {
+ params->trip_max_desired_temperature = last_passive;
+ } else if (found_first_passive) {
+ params->trip_max_desired_temperature = params->trip_switch_on;
+ params->trip_switch_on = INVALID_TRIP;
+ } else {
+ params->trip_switch_on = INVALID_TRIP;
+ params->trip_max_desired_temperature = last_active;
+ }
+}
+
+static void reset_pid_controller(struct power_allocator_params *params)
+{
+ params->err_integral = 0;
+ params->prev_err = 0;
+}
+
+static void allow_maximum_power(struct thermal_zone_device *tz)
+{
+ struct thermal_instance *instance;
+ struct power_allocator_params *params = tz->governor_data;
+
+ mutex_lock(&tz->lock);
+ list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
+ if ((instance->trip != params->trip_max_desired_temperature) ||
+ (!cdev_is_power_actor(instance->cdev)))
+ continue;
+
+ instance->target = 0;
+ mutex_lock(&instance->cdev->lock);
+ instance->cdev->updated = false;
+ mutex_unlock(&instance->cdev->lock);
+ thermal_cdev_update(instance->cdev);
+ }
+ mutex_unlock(&tz->lock);
+}
+
+/**
+ * power_allocator_bind() - bind the power_allocator governor to a thermal zone
+ * @tz: thermal zone to bind it to
+ *
+ * Initialize the PID controller parameters and bind it to the thermal
+ * zone.
+ *
+ * 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;
+ int control_temp;
+
+ params = kzalloc(sizeof(*params), GFP_KERNEL);
+ if (!params)
+ return -ENOMEM;
+
+ if (!tz->tzp) {
+ tz->tzp = kzalloc(sizeof(*tz->tzp), GFP_KERNEL);
+ if (!tz->tzp) {
+ ret = -ENOMEM;
+ goto free_params;
+ }
+
+ params->allocated_tzp = true;
+ }
+
+ if (!tz->tzp->sustainable_power)
+ dev_warn(&tz->device, "power_allocator: sustainable_power will be estimated\n");
+
+ get_governor_trips(tz, params);
+
+ 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);
+
+ tz->governor_data = params;
+
+ return 0;
+
+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;
+ int switch_on_temp, control_temp;
+ struct power_allocator_params *params = tz->governor_data;
+
+ /*
+ * We get called for every trip point but we only need to do
+ * our calculations once
+ */
+ if (trip != params->trip_max_desired_temperature)
+ return 0;
+
+ ret = tz->ops->get_trip_temp(tz, params->trip_switch_on,
+ &switch_on_temp);
+ if (!ret && (tz->temperature < switch_on_temp)) {
+ tz->passive = 0;
+ reset_pid_controller(params);
+ allow_maximum_power(tz);
+ return 0;
+ }
+
+ tz->passive = 1;
+
+ ret = tz->ops->get_trip_temp(tz, params->trip_max_desired_temperature,
+ &control_temp);
+ if (ret) {
+ dev_warn(&tz->device,
+ "Failed to get the maximum desired temperature: %d\n",
+ ret);
+ return ret;
+ }
+
+ return allocate_power(tz, control_temp);
+}
+
+static struct thermal_governor thermal_gov_power_allocator = {
+ .name = "power_allocator",
+ .bind_to_tz = power_allocator_bind,
+ .unbind_from_tz = power_allocator_unbind,
+ .throttle = power_allocator_throttle,
+};
+
+int thermal_gov_power_allocator_register(void)
+{
+ return thermal_register_governor(&thermal_gov_power_allocator);
+}
+
+void thermal_gov_power_allocator_unregister(void)
+{
+ thermal_unregister_governor(&thermal_gov_power_allocator);
+}