/* * 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); mutex_lock(&instance->cdev->lock); instance->cdev->updated = false; mutex_unlock(&instance->cdev->lock); 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); }