[linux-2.6-block.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 <trace/events/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,
 *       deactivate 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);

	if (!instance->initialized) {
		if (throttle) {
			next_target = (cur_state + 1) >= instance->upper ?
					instance->upper :
					((cur_state + 1) < instance->lower ?
					instance->lower : (cur_state + 1));
		} else {
			next_target = THERMAL_NO_TARGET;
		}

		return next_target;
	}

	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)
{
	int 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;
		trace_thermal_zone_trip(tz, trip, trip_type);
	}

	dev_dbg(&tz->device, "Trip%d[type=%d,temp=%d]: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 (instance->initialized && 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->initialized = true;
		instance->cdev->updated = false; /* cdev needs update */
	}

	mutex_unlock(&tz->lock);
}

/**
 * step_wise_throttle - throttles devices associated 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	25	#include <linux/thermal.h>
208cd822	26	#include <trace/events/thermal.h>
e151a202 D	27
	28	#include "thermal_core.h"
	29
	30	/*
	31	* If the temperature is higher than a trip point,
	32	* a. if the trend is THERMAL_TREND_RAISING, use higher cooling
	33	* state for this trip point
	34	* b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
	35	* state for this trip point
3dbfff3d ZR	36	* c. if the trend is THERMAL_TREND_RAISE_FULL, use upper limit
	37	* for this trip point
	38	* d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit
	39	* for this trip point
	40	* If the temperature is lower than a trip point,
	41	* a. if the trend is THERMAL_TREND_RAISING, do nothing
	42	* b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
	43	* state for this trip point, if the cooling state already
	44	* equals lower limit, deactivate the thermal instance
	45	* c. if the trend is THERMAL_TREND_RAISE_FULL, do nothing
	46	* d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit,
	47	* if the cooling state already equals lower limit,
56b613ea	48	* deactivate the thermal instance
e151a202 D	49	*/
e151a202 D	50	static unsigned long get_target_state(struct thermal_instance *instance,
3dbfff3d	51	enum thermal_trend trend, bool throttle)
e151a202 D	52	{
	53	struct thermal_cooling_device *cdev = instance->cdev;
	54	unsigned long cur_state;
ca56caa0	55	unsigned long next_target;
e151a202	56
ca56caa0 EV	57	/*
	58	* We keep this instance the way it is by default.
	59	* Otherwise, we use the current state of the
	60	* cdev in use to determine the next_target.
	61	*/
e151a202	62	cdev->ops->get_cur_state(cdev, &cur_state);
ca56caa0	63	next_target = instance->target;
06475b55	64	dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state);
e151a202	65
bb431ba2 ZR	66	if (!instance->initialized) {
	67	if (throttle) {
	68	next_target = (cur_state + 1) >= instance->upper ?
	69	instance->upper :
	70	((cur_state + 1) < instance->lower ?
	71	instance->lower : (cur_state + 1));
	72	} else {
	73	next_target = THERMAL_NO_TARGET;
	74	}
	75
	76	return next_target;
	77	}
	78
3dbfff3d ZR	79	switch (trend) {
3dbfff3d ZR	80	case THERMAL_TREND_RAISING:
e79fe642	81	if (throttle) {
ca56caa0	82	next_target = cur_state < instance->upper ?
3dbfff3d	83	(cur_state + 1) : instance->upper;
ca56caa0 EV	84	if (next_target < instance->lower)
ca56caa0 EV	85	next_target = instance->lower;
e79fe642	86	}
3dbfff3d ZR	87	break;
	88	case THERMAL_TREND_RAISE_FULL:
	89	if (throttle)
ca56caa0	90	next_target = instance->upper;
3dbfff3d ZR	91	break;
3dbfff3d ZR	92	case THERMAL_TREND_DROPPING:
26bb0e9a	93	if (cur_state <= instance->lower) {
3dbfff3d	94	if (!throttle)
ca56caa0	95	next_target = THERMAL_NO_TARGET;
e79fe642	96	} else {
ca56caa0 EV	97	next_target = cur_state - 1;
	98	if (next_target > instance->upper)
	99	next_target = instance->upper;
e79fe642	100	}
3dbfff3d ZR	101	break;
	102	case THERMAL_TREND_DROP_FULL:
	103	if (cur_state == instance->lower) {
	104	if (!throttle)
ca56caa0	105	next_target = THERMAL_NO_TARGET;
3dbfff3d	106	} else
ca56caa0	107	next_target = instance->lower;
3dbfff3d ZR	108	break;
	109	default:
	110	break;
e151a202 D	111	}
e151a202 D	112
ca56caa0	113	return next_target;
e151a202 D	114	}
	115
	116	static void update_passive_instance(struct thermal_zone_device *tz,
	117	enum thermal_trip_type type, int value)
	118	{
	119	/*
	120	* If value is +1, activate a passive instance.
	121	* If value is -1, deactivate a passive instance.
	122	*/
	123	if (type == THERMAL_TRIP_PASSIVE \|\| type == THERMAL_TRIPS_NONE)
	124	tz->passive += value;
	125	}
	126
e151a202 D	127	static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
e151a202 D	128	{
17e8351a	129	int trip_temp;
e151a202 D	130	enum thermal_trip_type trip_type;
e151a202 D	131	enum thermal_trend trend;
b8bb6cb9 ZR	132	struct thermal_instance *instance;
	133	bool throttle = false;
	134	int old_target;
e151a202 D	135
	136	if (trip == THERMAL_TRIPS_NONE) {
	137	trip_temp = tz->forced_passive;
	138	trip_type = THERMAL_TRIPS_NONE;
	139	} else {
	140	tz->ops->get_trip_temp(tz, trip, &trip_temp);
	141	tz->ops->get_trip_type(tz, trip, &trip_type);
	142	}
	143
	144	trend = get_tz_trend(tz, trip);
	145
208cd822	146	if (tz->temperature >= trip_temp) {
b8bb6cb9	147	throttle = true;
208cd822 PA	148	trace_thermal_zone_trip(tz, trip, trip_type);
208cd822 PA	149	}
b8bb6cb9	150
17e8351a	151	dev_dbg(&tz->device, "Trip%d[type=%d,temp=%d]:trend=%d,throttle=%d\n",
06475b55 AL	152	trip, trip_type, trip_temp, trend, throttle);
06475b55 AL	153
e151a202 D	154	mutex_lock(&tz->lock);
e151a202 D	155
b8bb6cb9 ZR	156	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
	157	if (instance->trip != trip)
	158	continue;
	159
	160	old_target = instance->target;
	161	instance->target = get_target_state(instance, trend, throttle);
06475b55 AL	162	dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
06475b55 AL	163	old_target, (int)instance->target);
b8bb6cb9	164
bb431ba2	165	if (instance->initialized && old_target == instance->target)
178c2490 SG	166	continue;
178c2490 SG	167
b8bb6cb9 ZR	168	/* Activate a passive thermal instance */
	169	if (old_target == THERMAL_NO_TARGET &&
	170	instance->target != THERMAL_NO_TARGET)
	171	update_passive_instance(tz, trip_type, 1);
	172	/* Deactivate a passive thermal instance */
	173	else if (old_target != THERMAL_NO_TARGET &&
	174	instance->target == THERMAL_NO_TARGET)
	175	update_passive_instance(tz, trip_type, -1);
	176
bb431ba2	177	instance->initialized = true;
b8bb6cb9 ZR	178	instance->cdev->updated = false; /* cdev needs update */
b8bb6cb9 ZR	179	}
e151a202 D	180
	181	mutex_unlock(&tz->lock);
	182	}
	183
	184	/**
56b613ea	185	* step_wise_throttle - throttles devices associated with the given zone
e151a202 D	186	* @tz - thermal_zone_device
	187	* @trip - the trip point
	188	* @trip_type - type of the trip point
	189	*
	190	* Throttling Logic: This uses the trend of the thermal zone to throttle.
	191	* If the thermal zone is 'heating up' this throttles all the cooling
	192	* devices associated with the zone and its particular trip point, by one
	193	* step. If the zone is 'cooling down' it brings back the performance of
	194	* the devices by one step.
	195	*/
b88a4977	196	static int step_wise_throttle(struct thermal_zone_device *tz, int trip)
e151a202 D	197	{
	198	struct thermal_instance *instance;
	199
	200	thermal_zone_trip_update(tz, trip);
	201
	202	if (tz->forced_passive)
	203	thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE);
	204
	205	mutex_lock(&tz->lock);
	206
	207	list_for_each_entry(instance, &tz->thermal_instances, tz_node)
	208	thermal_cdev_update(instance->cdev);
	209
	210	mutex_unlock(&tz->lock);
	211
	212	return 0;
	213	}
	214
b88a4977	215	static struct thermal_governor thermal_gov_step_wise = {
1f53ef17	216	.name = "step_wise",
e151a202	217	.throttle = step_wise_throttle,
e151a202 D	218	};
e151a202 D	219
80a26a5c	220	int thermal_gov_step_wise_register(void)
e151a202 D	221	{
	222	return thermal_register_governor(&thermal_gov_step_wise);
	223	}
	224
80a26a5c	225	void thermal_gov_step_wise_unregister(void)
e151a202 D	226	{
	227	thermal_unregister_governor(&thermal_gov_step_wise);
	228	}