This patch adds a simple step_wise governor to the generic thermal layer. This algorithm throttles the cooling devices in a linear fashion. If the 'trend' is heating, it throttles by one step. And if the thermal trend is cooling it de-throttles by one step. This actually moves the throttling logic from thermal_sys.c and puts inside step_wise.c, without any change. Signed-off-by: Durgadoss R <durgadoss.r@xxxxxxxxx> --- * This patch is a modified version of v4 series submitted here: http://www.spinics.net/lists/linux-acpi/msg37375.html * This patch removes the Kconfig option to always select step_wise as default governor. * I will submit a separate patch to let the user select a default thermal governor like how it is being done for cpufreq governors. drivers/thermal/Kconfig | 6 ++ drivers/thermal/Makefile | 1 + drivers/thermal/step_wise.c | 194 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 201 insertions(+) create mode 100644 drivers/thermal/step_wise.c diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index 2200912..becec31 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -59,3 +59,9 @@ config FAIR_SHARE depends on THERMAL help Enable this to manage platform thermals using fair-share governor. + +config STEP_WISE + bool "Step_wise thermal governor" + depends on THERMAL + help + Enable this to manage platform thermals using a simple linear diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index 30540dd..4e53c00 100644 --- a/drivers/thermal/Makefile +++ b/drivers/thermal/Makefile @@ -8,3 +8,4 @@ obj-$(CONFIG_SPEAR_THERMAL) += spear_thermal.o obj-$(CONFIG_RCAR_THERMAL) += rcar_thermal.o obj-$(CONFIG_EXYNOS_THERMAL) += exynos_thermal.o obj-$(CONFIG_FAIR_SHARE) += fair_share.o +obj-$(CONFIG_STEP_WISE) += step_wise.o diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c new file mode 100644 index 0000000..3f9cfcf --- /dev/null +++ b/drivers/thermal/step_wise.c @@ -0,0 +1,194 @@ +/* + * step_wise.c - A step-by-step Thermal throttling governor + * + * Copyright (C) 2012 Intel Corp + * Copyright (C) 2012 Durgadoss R <durgadoss.r@xxxxxxxxx> + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * 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 + */ +static unsigned long get_target_state(struct thermal_instance *instance, + enum thermal_trend trend) +{ + struct thermal_cooling_device *cdev = instance->cdev; + unsigned long cur_state; + + cdev->ops->get_cur_state(cdev, &cur_state); + + if (trend == THERMAL_TREND_RAISING) { + cur_state = cur_state < instance->upper ? + (cur_state + 1) : instance->upper; + } else if (trend == THERMAL_TREND_DROPPING) { + cur_state = cur_state > instance->lower ? + (cur_state - 1) : instance->lower; + } + + 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 update_instance_for_throttle(struct thermal_zone_device *tz, + int trip, enum thermal_trip_type trip_type, + enum thermal_trend trend) +{ + struct thermal_instance *instance; + + list_for_each_entry(instance, &tz->thermal_instances, tz_node) { + if (instance->trip != trip) + continue; + + instance->target = get_target_state(instance, trend); + + /* Activate a passive thermal instance */ + if (instance->target == THERMAL_NO_TARGET) + update_passive_instance(tz, trip_type, 1); + + instance->cdev->updated = false; /* cdev needs update */ + } +} + +static void update_instance_for_dethrottle(struct thermal_zone_device *tz, + int trip, enum thermal_trip_type trip_type) +{ + struct thermal_instance *instance; + struct thermal_cooling_device *cdev; + unsigned long cur_state; + + list_for_each_entry(instance, &tz->thermal_instances, tz_node) { + if (instance->trip != trip || + instance->target == THERMAL_NO_TARGET) + continue; + + cdev = instance->cdev; + cdev->ops->get_cur_state(cdev, &cur_state); + + instance->target = cur_state > instance->lower ? + (cur_state - 1) : THERMAL_NO_TARGET; + + /* Deactivate a passive thermal instance */ + if (instance->target == THERMAL_NO_TARGET) + update_passive_instance(tz, trip_type, -1); + + cdev->updated = false; /* cdev needs update */ + } +} + +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; + + 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); + + mutex_lock(&tz->lock); + + if (tz->temperature >= trip_temp) + update_instance_for_throttle(tz, trip, trip_type, trend); + else + update_instance_for_dethrottle(tz, trip, trip_type); + + 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. + */ +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; +} + +struct thermal_governor thermal_gov_step_wise = { + .name = DEFAULT_THERMAL_GOVERNOR, + .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"); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
