1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * fair_share.c - A simple weight based Thermal governor 4 * 5 * Copyright (C) 2012 Intel Corp 6 * Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com> 7 * 8 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 9 * 10 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 11 */ 12 13 #include <linux/thermal.h> 14 #include "thermal_trace.h" 15 16 #include "thermal_core.h" 17 18 static int get_trip_level(struct thermal_zone_device *tz) 19 { 20 const struct thermal_trip *trip, *level_trip = NULL; 21 int trip_level = -1; 22 23 for_each_trip(tz, trip) { 24 if (trip->temperature >= tz->temperature) 25 continue; 26 27 trip_level++; 28 29 if (!level_trip || trip->temperature > level_trip->temperature) 30 level_trip = trip; 31 } 32 33 /* Bail out if the temperature is not greater than any trips. */ 34 if (trip_level < 0) 35 return 0; 36 37 trace_thermal_zone_trip(tz, thermal_zone_trip_id(tz, level_trip), 38 level_trip->type); 39 40 return trip_level; 41 } 42 43 static long get_target_state(struct thermal_zone_device *tz, 44 struct thermal_cooling_device *cdev, int percentage, int level) 45 { 46 return (long)(percentage * level * cdev->max_state) / (100 * tz->num_trips); 47 } 48 49 /** 50 * fair_share_throttle - throttles devices associated with the given zone 51 * @tz: thermal_zone_device 52 * @trip: trip point 53 * 54 * Throttling Logic: This uses three parameters to calculate the new 55 * throttle state of the cooling devices associated with the given zone. 56 * 57 * Parameters used for Throttling: 58 * P1. max_state: Maximum throttle state exposed by the cooling device. 59 * P2. percentage[i]/100: 60 * How 'effective' the 'i'th device is, in cooling the given zone. 61 * P3. cur_trip_level/max_no_of_trips: 62 * This describes the extent to which the devices should be throttled. 63 * We do not want to throttle too much when we trip a lower temperature, 64 * whereas the throttling is at full swing if we trip critical levels. 65 * (Heavily assumes the trip points are in ascending order) 66 * new_state of cooling device = P3 * P2 * P1 67 */ 68 static int fair_share_throttle(struct thermal_zone_device *tz, 69 const struct thermal_trip *trip) 70 { 71 struct thermal_instance *instance; 72 int total_weight = 0; 73 int total_instance = 0; 74 int cur_trip_level = get_trip_level(tz); 75 76 lockdep_assert_held(&tz->lock); 77 78 list_for_each_entry(instance, &tz->thermal_instances, tz_node) { 79 if (instance->trip != trip) 80 continue; 81 82 total_weight += instance->weight; 83 total_instance++; 84 } 85 86 list_for_each_entry(instance, &tz->thermal_instances, tz_node) { 87 int percentage; 88 struct thermal_cooling_device *cdev = instance->cdev; 89 90 if (instance->trip != trip) 91 continue; 92 93 if (!total_weight) 94 percentage = 100 / total_instance; 95 else 96 percentage = (instance->weight * 100) / total_weight; 97 98 instance->target = get_target_state(tz, cdev, percentage, 99 cur_trip_level); 100 101 mutex_lock(&cdev->lock); 102 __thermal_cdev_update(cdev); 103 mutex_unlock(&cdev->lock); 104 } 105 106 return 0; 107 } 108 109 static struct thermal_governor thermal_gov_fair_share = { 110 .name = "fair_share", 111 .throttle = fair_share_throttle, 112 }; 113 THERMAL_GOVERNOR_DECLARE(thermal_gov_fair_share); 114