linux/drivers/thermal/fair_share.c
Sascha Hauer 17e8351a77 thermal: consistently use int for temperatures
The thermal code uses int, long and unsigned long for temperatures
in different places.

Using an unsigned type limits the thermal framework to positive
temperatures without need. Also several drivers currently will report
temperatures near UINT_MAX for temperatures below 0°C. This will probably
immediately shut the machine down due to overtemperature if started below
0°C.

'long' is 64bit on several architectures. This is not needed since INT_MAX °mC
is above the melting point of all known materials.

Consistently use a plain 'int' for temperatures throughout the thermal code and
the drivers. This only changes the places in the drivers where the temperature
is passed around as pointer, when drivers internally use another type this is
not changed.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Peter Feuerer <peter@piie.net>
Cc: Punit Agrawal <punit.agrawal@arm.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Jean Delvare <jdelvare@suse.de>
Cc: Peter Feuerer <peter@piie.net>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Lukasz Majewski <l.majewski@samsung.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-acpi@vger.kernel.org
Cc: platform-driver-x86@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-omap@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: lm-sensors@lm-sensors.org
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2015-08-03 23:15:50 +08:00

140 lines
4.0 KiB
C

/*
* fair_share.c - A simple weight based Thermal 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"
/**
* get_trip_level: - obtains the current trip level for a zone
* @tz: thermal zone device
*/
static int get_trip_level(struct thermal_zone_device *tz)
{
int count = 0;
int trip_temp;
enum thermal_trip_type trip_type;
if (tz->trips == 0 || !tz->ops->get_trip_temp)
return 0;
for (count = 0; count < tz->trips; count++) {
tz->ops->get_trip_temp(tz, count, &trip_temp);
if (tz->temperature < trip_temp)
break;
}
/*
* count > 0 only if temperature is greater than first trip
* point, in which case, trip_point = count - 1
*/
if (count > 0) {
tz->ops->get_trip_type(tz, count - 1, &trip_type);
trace_thermal_zone_trip(tz, count - 1, trip_type);
}
return count;
}
static long get_target_state(struct thermal_zone_device *tz,
struct thermal_cooling_device *cdev, int percentage, int level)
{
unsigned long max_state;
cdev->ops->get_max_state(cdev, &max_state);
return (long)(percentage * level * max_state) / (100 * tz->trips);
}
/**
* fair_share_throttle - throttles devices associated with the given zone
* @tz - thermal_zone_device
*
* Throttling Logic: This uses three parameters to calculate the new
* throttle state of the cooling devices associated with the given zone.
*
* Parameters used for Throttling:
* P1. max_state: Maximum throttle state exposed by the cooling device.
* P2. percentage[i]/100:
* How 'effective' the 'i'th device is, in cooling the given zone.
* P3. cur_trip_level/max_no_of_trips:
* This describes the extent to which the devices should be throttled.
* We do not want to throttle too much when we trip a lower temperature,
* whereas the throttling is at full swing if we trip critical levels.
* (Heavily assumes the trip points are in ascending order)
* new_state of cooling device = P3 * P2 * P1
*/
static int fair_share_throttle(struct thermal_zone_device *tz, int trip)
{
struct thermal_instance *instance;
int total_weight = 0;
int total_instance = 0;
int cur_trip_level = get_trip_level(tz);
list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
if (instance->trip != trip)
continue;
total_weight += instance->weight;
total_instance++;
}
list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
int percentage;
struct thermal_cooling_device *cdev = instance->cdev;
if (instance->trip != trip)
continue;
if (!total_weight)
percentage = 100 / total_instance;
else
percentage = (instance->weight * 100) / total_weight;
instance->target = get_target_state(tz, cdev, percentage,
cur_trip_level);
instance->cdev->updated = false;
thermal_cdev_update(cdev);
}
return 0;
}
static struct thermal_governor thermal_gov_fair_share = {
.name = "fair_share",
.throttle = fair_share_throttle,
};
int thermal_gov_fair_share_register(void)
{
return thermal_register_governor(&thermal_gov_fair_share);
}
void thermal_gov_fair_share_unregister(void)
{
thermal_unregister_governor(&thermal_gov_fair_share);
}