thermal/governors: Prefix all source files with gov_

Bang-bang governor source file is prefixed with gov_. Do the same for
other governors for consistency so they're easy to find in the sources.

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/b9a85d3204712f14e320504948c12712dc0b291b.1589199124.git.amit.kucheria@linaro.org

1 files changed, 0 insertions, 654 deletions

diff --git a/drivers/thermal/power_allocator.c b/drivers/thermal/power_allocator.c
deleted file mode 100644
index 44636475b2a3..000000000000
--- a/drivers/thermal/power_allocator.c
+++ /dev/null
@@ -1,654 +0,0 @@
-/*
- * 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,
-};
-THERMAL_GOVERNOR_DECLARE(thermal_gov_power_allocator);