[deliverable/linux.git] / drivers / thermal / step_wise.c

/*
 *  step_wise.c - A step-by-step Thermal throttling governor
 *
 *  Copyright (C) 2012 Intel Corp
 *  Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com>
 *
 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/thermal.h>

#include "thermal_core.h"

/*
 * If the temperature is higher than a trip point,
 *    a. if the trend is THERMAL_TREND_RAISING, use higher cooling
 *       state for this trip point
 *    b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
 *       state for this trip point
 *    c. if the trend is THERMAL_TREND_RAISE_FULL, use upper limit
 *       for this trip point
 *    d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit
 *       for this trip point
 * If the temperature is lower than a trip point,
 *    a. if the trend is THERMAL_TREND_RAISING, do nothing
 *    b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
 *       state for this trip point, if the cooling state already
 *       equals lower limit, deactivate the thermal instance
 *    c. if the trend is THERMAL_TREND_RAISE_FULL, do nothing
 *    d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit,
 *       if the cooling state already equals lower limit,
 *       deactive the thermal instance
 */
static unsigned long get_target_state(struct thermal_instance *instance,
				enum thermal_trend trend, bool throttle)
{
	struct thermal_cooling_device *cdev = instance->cdev;
	unsigned long cur_state;

	cdev->ops->get_cur_state(cdev, &cur_state);

	switch (trend) {
	case THERMAL_TREND_RAISING:
		if (throttle)
			cur_state = cur_state < instance->upper ?
				    (cur_state + 1) : instance->upper;
		break;
	case THERMAL_TREND_RAISE_FULL:
		if (throttle)
			cur_state = instance->upper;
		break;
	case THERMAL_TREND_DROPPING:
		if (cur_state == instance->lower) {
			if (!throttle)
				cur_state = -1;
		} else
			cur_state -= 1;
		break;
	case THERMAL_TREND_DROP_FULL:
		if (cur_state == instance->lower) {
			if (!throttle)
				cur_state = -1;
		} else
			cur_state = instance->lower;
		break;
	default:
		break;
	}

	return cur_state;
}

static void update_passive_instance(struct thermal_zone_device *tz,
				enum thermal_trip_type type, int value)
{
	/*
	 * If value is +1, activate a passive instance.
	 * If value is -1, deactivate a passive instance.
	 */
	if (type == THERMAL_TRIP_PASSIVE || type == THERMAL_TRIPS_NONE)
		tz->passive += value;
}

static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
{
	long trip_temp;
	enum thermal_trip_type trip_type;
	enum thermal_trend trend;
	struct thermal_instance *instance;
	bool throttle = false;
	int old_target;

	if (trip == THERMAL_TRIPS_NONE) {
		trip_temp = tz->forced_passive;
		trip_type = THERMAL_TRIPS_NONE;
	} else {
		tz->ops->get_trip_temp(tz, trip, &trip_temp);
		tz->ops->get_trip_type(tz, trip, &trip_type);
	}

	trend = get_tz_trend(tz, trip);

	if (tz->temperature >= trip_temp)
		throttle = true;

	mutex_lock(&tz->lock);

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

		old_target = instance->target;
		instance->target = get_target_state(instance, trend, throttle);

		/* Activate a passive thermal instance */
		if (old_target == THERMAL_NO_TARGET &&
			instance->target != THERMAL_NO_TARGET)
			update_passive_instance(tz, trip_type, 1);
		/* Deactivate a passive thermal instance */
		else if (old_target != THERMAL_NO_TARGET &&
			instance->target == THERMAL_NO_TARGET)
			update_passive_instance(tz, trip_type, -1);


		instance->cdev->updated = false; /* cdev needs update */
	}

	mutex_unlock(&tz->lock);
}

/**
 * step_wise_throttle - throttles devices asscciated with the given zone
 * @tz - thermal_zone_device
 * @trip - the trip point
 * @trip_type - type of the trip point
 *
 * Throttling Logic: This uses the trend of the thermal zone to throttle.
 * If the thermal zone is 'heating up' this throttles all the cooling
 * devices associated with the zone and its particular trip point, by one
 * step. If the zone is 'cooling down' it brings back the performance of
 * the devices by one step.
 */
static int step_wise_throttle(struct thermal_zone_device *tz, int trip)
{
	struct thermal_instance *instance;

	thermal_zone_trip_update(tz, trip);

	if (tz->forced_passive)
		thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE);

	mutex_lock(&tz->lock);

	list_for_each_entry(instance, &tz->thermal_instances, tz_node)
		thermal_cdev_update(instance->cdev);

	mutex_unlock(&tz->lock);

	return 0;
}

static struct thermal_governor thermal_gov_step_wise = {
	.name		= "step_wise",
	.throttle	= step_wise_throttle,
	.owner		= THIS_MODULE,
};

static int __init thermal_gov_step_wise_init(void)
{
	return thermal_register_governor(&thermal_gov_step_wise);
}

static void __exit thermal_gov_step_wise_exit(void)
{
	thermal_unregister_governor(&thermal_gov_step_wise);
}

/* This should load after thermal framework */
fs_initcall(thermal_gov_step_wise_init);
module_exit(thermal_gov_step_wise_exit);

MODULE_AUTHOR("Durgadoss R");
MODULE_DESCRIPTION("A step-by-step thermal throttling governor");
MODULE_LICENSE("GPL");
Commit	Line	Data
e151a202 D	1	/*
	2	* step_wise.c - A step-by-step Thermal throttling governor
	3	*
	4	* Copyright (C) 2012 Intel Corp
	5	* Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com>
	6	*
	7	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License as published by
	11	* the Free Software Foundation; version 2 of the License.
	12	*
	13	* This program is distributed in the hope that it will be useful, but
	14	* WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU General Public License along
	19	* with this program; if not, write to the Free Software Foundation, Inc.,
	20	* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
	21	*
	22	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	23	*/
	24
	25	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	26
	27	#include <linux/module.h>
	28	#include <linux/thermal.h>
	29
	30	#include "thermal_core.h"
	31
	32	/*
	33	* If the temperature is higher than a trip point,
	34	* a. if the trend is THERMAL_TREND_RAISING, use higher cooling
	35	* state for this trip point
	36	* b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
	37	* state for this trip point
3dbfff3d ZR	38	* c. if the trend is THERMAL_TREND_RAISE_FULL, use upper limit
	39	* for this trip point
	40	* d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit
	41	* for this trip point
	42	* If the temperature is lower than a trip point,
	43	* a. if the trend is THERMAL_TREND_RAISING, do nothing
	44	* b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
	45	* state for this trip point, if the cooling state already
	46	* equals lower limit, deactivate the thermal instance
	47	* c. if the trend is THERMAL_TREND_RAISE_FULL, do nothing
	48	* d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit,
	49	* if the cooling state already equals lower limit,
	50	* deactive the thermal instance
e151a202 D	51	*/
e151a202 D	52	static unsigned long get_target_state(struct thermal_instance *instance,
3dbfff3d	53	enum thermal_trend trend, bool throttle)
e151a202 D	54	{
	55	struct thermal_cooling_device *cdev = instance->cdev;
	56	unsigned long cur_state;
	57
	58	cdev->ops->get_cur_state(cdev, &cur_state);
	59
3dbfff3d ZR	60	switch (trend) {
	61	case THERMAL_TREND_RAISING:
	62	if (throttle)
	63	cur_state = cur_state < instance->upper ?
	64	(cur_state + 1) : instance->upper;
	65	break;
	66	case THERMAL_TREND_RAISE_FULL:
	67	if (throttle)
	68	cur_state = instance->upper;
	69	break;
	70	case THERMAL_TREND_DROPPING:
	71	if (cur_state == instance->lower) {
	72	if (!throttle)
	73	cur_state = -1;
	74	} else
	75	cur_state -= 1;
	76	break;
	77	case THERMAL_TREND_DROP_FULL:
	78	if (cur_state == instance->lower) {
	79	if (!throttle)
	80	cur_state = -1;
	81	} else
	82	cur_state = instance->lower;
	83	break;
	84	default:
	85	break;
e151a202 D	86	}
	87
	88	return cur_state;
	89	}
	90
	91	static void update_passive_instance(struct thermal_zone_device *tz,
	92	enum thermal_trip_type type, int value)
	93	{
	94	/*
	95	* If value is +1, activate a passive instance.
	96	* If value is -1, deactivate a passive instance.
	97	*/
	98	if (type == THERMAL_TRIP_PASSIVE \|\| type == THERMAL_TRIPS_NONE)
	99	tz->passive += value;
	100	}
	101
e151a202 D	102	static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
	103	{
	104	long trip_temp;
	105	enum thermal_trip_type trip_type;
	106	enum thermal_trend trend;
b8bb6cb9 ZR	107	struct thermal_instance *instance;
	108	bool throttle = false;
	109	int old_target;
e151a202 D	110
	111	if (trip == THERMAL_TRIPS_NONE) {
	112	trip_temp = tz->forced_passive;
	113	trip_type = THERMAL_TRIPS_NONE;
	114	} else {
	115	tz->ops->get_trip_temp(tz, trip, &trip_temp);
	116	tz->ops->get_trip_type(tz, trip, &trip_type);
	117	}
	118
	119	trend = get_tz_trend(tz, trip);
	120
b8bb6cb9 ZR	121	if (tz->temperature >= trip_temp)
	122	throttle = true;
	123
e151a202 D	124	mutex_lock(&tz->lock);
e151a202 D	125
b8bb6cb9 ZR	126	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
	127	if (instance->trip != trip)
	128	continue;
	129
	130	old_target = instance->target;
	131	instance->target = get_target_state(instance, trend, throttle);
	132
	133	/* Activate a passive thermal instance */
	134	if (old_target == THERMAL_NO_TARGET &&
	135	instance->target != THERMAL_NO_TARGET)
	136	update_passive_instance(tz, trip_type, 1);
	137	/* Deactivate a passive thermal instance */
	138	else if (old_target != THERMAL_NO_TARGET &&
	139	instance->target == THERMAL_NO_TARGET)
	140	update_passive_instance(tz, trip_type, -1);
	141
	142
	143	instance->cdev->updated = false; /* cdev needs update */
	144	}
e151a202 D	145
	146	mutex_unlock(&tz->lock);
	147	}
	148
	149	/**
	150	* step_wise_throttle - throttles devices asscciated with the given zone
	151	* @tz - thermal_zone_device
	152	* @trip - the trip point
	153	* @trip_type - type of the trip point
	154	*
	155	* Throttling Logic: This uses the trend of the thermal zone to throttle.
	156	* If the thermal zone is 'heating up' this throttles all the cooling
	157	* devices associated with the zone and its particular trip point, by one
	158	* step. If the zone is 'cooling down' it brings back the performance of
	159	* the devices by one step.
	160	*/
b88a4977	161	static int step_wise_throttle(struct thermal_zone_device *tz, int trip)
e151a202 D	162	{
	163	struct thermal_instance *instance;
	164
	165	thermal_zone_trip_update(tz, trip);
	166
	167	if (tz->forced_passive)
	168	thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE);
	169
	170	mutex_lock(&tz->lock);
	171
	172	list_for_each_entry(instance, &tz->thermal_instances, tz_node)
	173	thermal_cdev_update(instance->cdev);
	174
	175	mutex_unlock(&tz->lock);
	176
	177	return 0;
	178	}
	179
b88a4977	180	static struct thermal_governor thermal_gov_step_wise = {
1f53ef17	181	.name = "step_wise",
e151a202 D	182	.throttle = step_wise_throttle,
	183	.owner = THIS_MODULE,
	184	};
	185
	186	static int __init thermal_gov_step_wise_init(void)
	187	{
	188	return thermal_register_governor(&thermal_gov_step_wise);
	189	}
	190
	191	static void __exit thermal_gov_step_wise_exit(void)
	192	{
	193	thermal_unregister_governor(&thermal_gov_step_wise);
	194	}
	195
	196	/* This should load after thermal framework */
	197	fs_initcall(thermal_gov_step_wise_init);
	198	module_exit(thermal_gov_step_wise_exit);
	199
	200	MODULE_AUTHOR("Durgadoss R");
	201	MODULE_DESCRIPTION("A step-by-step thermal throttling governor");
	202	MODULE_LICENSE("GPL");