linux/drivers/thermal/step_wise.c
Zhang Rui 80a26a5c22 Thermal: build thermal governors into thermal_sys module
The thermal governors are part of the thermal framework,
rather than a seperate feature/module.
Because the generic thermal layer can not work without
thermal governors, and it must load the thermal governors
during its initialization.

Build them into one module in this patch.

This also fix a problem that the generic thermal layer does not
work when CONFIG_THERMAL=m and CONFIG_THERMAL_GOV_XXX=y.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Eduardo Valentin <eduardo.valentin@ti.com>
Acked-by: Durgadoss R <durgadoss.r@intel.com>
2013-04-14 23:28:43 +08:00

197 lines
5.7 KiB
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;
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;
if (cur_state < instance->lower)
cur_state = instance->lower;
}
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;
if (cur_state > instance->upper)
cur_state = instance->upper;
}
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,
};
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);
}