[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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#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;
	unsigned long next_target;

	/*
	 * We keep this instance the way it is by default.
	 * Otherwise, we use the current state of the
	 * cdev in use to determine the next_target.
	 */
	cdev->ops->get_cur_state(cdev, &cur_state);
	next_target = instance->target;
	dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state);

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

	return next_target;
}

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;

	dev_dbg(&tz->device, "Trip%d[type=%d,temp=%ld]:trend=%d,throttle=%d\n",
				trip, trip_type, trip_temp, trend, throttle);

	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);
		dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
					old_target, (int)instance->target);

		if (old_target == instance->target)
			continue;

		/* 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,
};

int thermal_gov_step_wise_register(void)
{
	return thermal_register_governor(&thermal_gov_step_wise);
}

void thermal_gov_step_wise_unregister(void)
{
	thermal_unregister_governor(&thermal_gov_step_wise);
}
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
e151a202 D	25	#include <linux/thermal.h>
	26
	27	#include "thermal_core.h"
	28
	29	/*
	30	* If the temperature is higher than a trip point,
	31	* a. if the trend is THERMAL_TREND_RAISING, use higher cooling
	32	* state for this trip point
	33	* b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
	34	* state for this trip point
3dbfff3d ZR	35	* c. if the trend is THERMAL_TREND_RAISE_FULL, use upper limit
	36	* for this trip point
	37	* d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit
	38	* for this trip point
	39	* If the temperature is lower than a trip point,
	40	* a. if the trend is THERMAL_TREND_RAISING, do nothing
	41	* b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
	42	* state for this trip point, if the cooling state already
	43	* equals lower limit, deactivate the thermal instance
	44	* c. if the trend is THERMAL_TREND_RAISE_FULL, do nothing
	45	* d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit,
	46	* if the cooling state already equals lower limit,
	47	* deactive the thermal instance
e151a202 D	48	*/
e151a202 D	49	static unsigned long get_target_state(struct thermal_instance *instance,
3dbfff3d	50	enum thermal_trend trend, bool throttle)
e151a202 D	51	{
	52	struct thermal_cooling_device *cdev = instance->cdev;
	53	unsigned long cur_state;
ca56caa0	54	unsigned long next_target;
e151a202	55
ca56caa0 EV	56	/*
	57	* We keep this instance the way it is by default.
	58	* Otherwise, we use the current state of the
	59	* cdev in use to determine the next_target.
	60	*/
e151a202	61	cdev->ops->get_cur_state(cdev, &cur_state);
ca56caa0	62	next_target = instance->target;
06475b55	63	dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state);
e151a202	64
3dbfff3d ZR	65	switch (trend) {
3dbfff3d ZR	66	case THERMAL_TREND_RAISING:
e79fe642	67	if (throttle) {
ca56caa0	68	next_target = cur_state < instance->upper ?
3dbfff3d	69	(cur_state + 1) : instance->upper;
ca56caa0 EV	70	if (next_target < instance->lower)
ca56caa0 EV	71	next_target = instance->lower;
e79fe642	72	}
3dbfff3d ZR	73	break;
	74	case THERMAL_TREND_RAISE_FULL:
	75	if (throttle)
ca56caa0	76	next_target = instance->upper;
3dbfff3d ZR	77	break;
	78	case THERMAL_TREND_DROPPING:
	79	if (cur_state == instance->lower) {
	80	if (!throttle)
ca56caa0	81	next_target = THERMAL_NO_TARGET;
e79fe642	82	} else {
ca56caa0 EV	83	next_target = cur_state - 1;
	84	if (next_target > instance->upper)
	85	next_target = instance->upper;
e79fe642	86	}
3dbfff3d ZR	87	break;
	88	case THERMAL_TREND_DROP_FULL:
	89	if (cur_state == instance->lower) {
	90	if (!throttle)
ca56caa0	91	next_target = THERMAL_NO_TARGET;
3dbfff3d	92	} else
ca56caa0	93	next_target = instance->lower;
3dbfff3d ZR	94	break;
	95	default:
	96	break;
e151a202 D	97	}
e151a202 D	98
ca56caa0	99	return next_target;
e151a202 D	100	}
	101
	102	static void update_passive_instance(struct thermal_zone_device *tz,
	103	enum thermal_trip_type type, int value)
	104	{
	105	/*
	106	* If value is +1, activate a passive instance.
	107	* If value is -1, deactivate a passive instance.
	108	*/
	109	if (type == THERMAL_TRIP_PASSIVE \|\| type == THERMAL_TRIPS_NONE)
	110	tz->passive += value;
	111	}
	112
e151a202 D	113	static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
	114	{
	115	long trip_temp;
	116	enum thermal_trip_type trip_type;
	117	enum thermal_trend trend;
b8bb6cb9 ZR	118	struct thermal_instance *instance;
	119	bool throttle = false;
	120	int old_target;
e151a202 D	121
	122	if (trip == THERMAL_TRIPS_NONE) {
	123	trip_temp = tz->forced_passive;
	124	trip_type = THERMAL_TRIPS_NONE;
	125	} else {
	126	tz->ops->get_trip_temp(tz, trip, &trip_temp);
	127	tz->ops->get_trip_type(tz, trip, &trip_type);
	128	}
	129
	130	trend = get_tz_trend(tz, trip);
	131
b8bb6cb9 ZR	132	if (tz->temperature >= trip_temp)
	133	throttle = true;
	134
06475b55 AL	135	dev_dbg(&tz->device, "Trip%d[type=%d,temp=%ld]:trend=%d,throttle=%d\n",
	136	trip, trip_type, trip_temp, trend, throttle);
	137
e151a202 D	138	mutex_lock(&tz->lock);
e151a202 D	139
b8bb6cb9 ZR	140	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
	141	if (instance->trip != trip)
	142	continue;
	143
	144	old_target = instance->target;
	145	instance->target = get_target_state(instance, trend, throttle);
06475b55 AL	146	dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
06475b55 AL	147	old_target, (int)instance->target);
b8bb6cb9	148
178c2490 SG	149	if (old_target == instance->target)
	150	continue;
	151
b8bb6cb9 ZR	152	/* Activate a passive thermal instance */
	153	if (old_target == THERMAL_NO_TARGET &&
	154	instance->target != THERMAL_NO_TARGET)
	155	update_passive_instance(tz, trip_type, 1);
	156	/* Deactivate a passive thermal instance */
	157	else if (old_target != THERMAL_NO_TARGET &&
	158	instance->target == THERMAL_NO_TARGET)
	159	update_passive_instance(tz, trip_type, -1);
	160
	161
	162	instance->cdev->updated = false; /* cdev needs update */
	163	}
e151a202 D	164
	165	mutex_unlock(&tz->lock);
	166	}
	167
	168	/**
	169	* step_wise_throttle - throttles devices asscciated with the given zone
	170	* @tz - thermal_zone_device
	171	* @trip - the trip point
	172	* @trip_type - type of the trip point
	173	*
	174	* Throttling Logic: This uses the trend of the thermal zone to throttle.
	175	* If the thermal zone is 'heating up' this throttles all the cooling
	176	* devices associated with the zone and its particular trip point, by one
	177	* step. If the zone is 'cooling down' it brings back the performance of
	178	* the devices by one step.
	179	*/
b88a4977	180	static int step_wise_throttle(struct thermal_zone_device *tz, int trip)
e151a202 D	181	{
	182	struct thermal_instance *instance;
	183
	184	thermal_zone_trip_update(tz, trip);
	185
	186	if (tz->forced_passive)
	187	thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE);
	188
	189	mutex_lock(&tz->lock);
	190
	191	list_for_each_entry(instance, &tz->thermal_instances, tz_node)
	192	thermal_cdev_update(instance->cdev);
	193
	194	mutex_unlock(&tz->lock);
	195
	196	return 0;
	197	}
	198
b88a4977	199	static struct thermal_governor thermal_gov_step_wise = {
1f53ef17	200	.name = "step_wise",
e151a202	201	.throttle = step_wise_throttle,
e151a202 D	202	};
e151a202 D	203
80a26a5c	204	int thermal_gov_step_wise_register(void)
e151a202 D	205	{
	206	return thermal_register_governor(&thermal_gov_step_wise);
	207	}
	208
80a26a5c	209	void thermal_gov_step_wise_unregister(void)
e151a202 D	210	{
	211	thermal_unregister_governor(&thermal_gov_step_wise);
	212	}