1/* 2 * fair_share.c - A simple weight based Thermal 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 25#include <linux/thermal.h> 26#include <trace/events/thermal.h> 27 28#include "thermal_core.h" 29 30/** 31 * get_trip_level: - obtains the current trip level for a zone 32 * @tz: thermal zone device 33 */ 34static int get_trip_level(struct thermal_zone_device *tz) 35{ 36 int count = 0; 37 unsigned long trip_temp; 38 enum thermal_trip_type trip_type; 39 40 if (tz->trips == 0 || !tz->ops->get_trip_temp) 41 return 0; 42 43 for (count = 0; count < tz->trips; count++) { 44 tz->ops->get_trip_temp(tz, count, &trip_temp); 45 if (tz->temperature < trip_temp) 46 break; 47 } 48 49 /* 50 * count > 0 only if temperature is greater than first trip 51 * point, in which case, trip_point = count - 1 52 */ 53 if (count > 0) { 54 tz->ops->get_trip_type(tz, count - 1, &trip_type); 55 trace_thermal_zone_trip(tz, count - 1, trip_type); 56 } 57 58 return count; 59} 60 61static long get_target_state(struct thermal_zone_device *tz, 62 struct thermal_cooling_device *cdev, int weight, int level) 63{ 64 unsigned long max_state; 65 66 cdev->ops->get_max_state(cdev, &max_state); 67 68 return (long)(weight * level * max_state) / (100 * tz->trips); 69} 70 71/** 72 * fair_share_throttle - throttles devices asscciated with the given zone 73 * @tz - thermal_zone_device 74 * 75 * Throttling Logic: This uses three parameters to calculate the new 76 * throttle state of the cooling devices associated with the given zone. 77 * 78 * Parameters used for Throttling: 79 * P1. max_state: Maximum throttle state exposed by the cooling device. 80 * P2. weight[i]/100: 81 * How 'effective' the 'i'th device is, in cooling the given zone. 82 * P3. cur_trip_level/max_no_of_trips: 83 * This describes the extent to which the devices should be throttled. 84 * We do not want to throttle too much when we trip a lower temperature, 85 * whereas the throttling is at full swing if we trip critical levels. 86 * (Heavily assumes the trip points are in ascending order) 87 * new_state of cooling device = P3 * P2 * P1 88 */ 89static int fair_share_throttle(struct thermal_zone_device *tz, int trip) 90{ 91 const struct thermal_zone_params *tzp; 92 struct thermal_cooling_device *cdev; 93 struct thermal_instance *instance; 94 int i; 95 int cur_trip_level = get_trip_level(tz); 96 97 if (!tz->tzp || !tz->tzp->tbp) 98 return -EINVAL; 99 100 tzp = tz->tzp; 101 102 for (i = 0; i < tzp->num_tbps; i++) { 103 if (!tzp->tbp[i].cdev) 104 continue; 105 106 cdev = tzp->tbp[i].cdev; 107 instance = get_thermal_instance(tz, cdev, trip); 108 if (!instance) 109 continue; 110 111 instance->target = get_target_state(tz, cdev, 112 tzp->tbp[i].weight, cur_trip_level); 113 114 instance->cdev->updated = false; 115 thermal_cdev_update(cdev); 116 } 117 return 0; 118} 119 120static struct thermal_governor thermal_gov_fair_share = { 121 .name = "fair_share", 122 .throttle = fair_share_throttle, 123}; 124 125int thermal_gov_fair_share_register(void) 126{ 127 return thermal_register_governor(&thermal_gov_fair_share); 128} 129 130void thermal_gov_fair_share_unregister(void) 131{ 132 thermal_unregister_governor(&thermal_gov_fair_share); 133} 134 135