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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * fair_share.c - A simple weight based Thermal governor4 *5 * Copyright (C) 2012 Intel Corp6 * 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 18static int get_trip_level(struct thermal_zone_device *tz)19{20 const struct thermal_trip_desc *level_td = NULL;21 const struct thermal_trip_desc *td;22 int trip_level = -1;23 24 for_each_trip_desc(tz, td) {25 if (td->threshold > tz->temperature)26 continue;27 28 trip_level++;29 30 if (!level_td || td->threshold > level_td->threshold)31 level_td = td;32 }33 34 /* Bail out if the temperature is not greater than any trips. */35 if (trip_level < 0)36 return 0;37 38 trace_thermal_zone_trip(tz, thermal_zone_trip_id(tz, &level_td->trip),39 level_td->trip.type);40 41 return trip_level;42}43 44/**45 * fair_share_throttle - throttles devices associated with the given zone46 * @tz: thermal_zone_device47 * @trip: trip point48 * @trip_level: number of trips crossed by the zone temperature49 *50 * Throttling Logic: This uses three parameters to calculate the new51 * throttle state of the cooling devices associated with the given zone.52 *53 * Parameters used for Throttling:54 * P1. max_state: Maximum throttle state exposed by the cooling device.55 * P2. weight[i]/total_weight:56 * How 'effective' the 'i'th device is, in cooling the given zone.57 * P3. trip_level/max_no_of_trips:58 * This describes the extent to which the devices should be throttled.59 * We do not want to throttle too much when we trip a lower temperature,60 * whereas the throttling is at full swing if we trip critical levels.61 * new_state of cooling device = P3 * P2 * P162 */63static void fair_share_throttle(struct thermal_zone_device *tz,64 const struct thermal_trip *trip,65 int trip_level)66{67 struct thermal_instance *instance;68 int total_weight = 0;69 int nr_instances = 0;70 71 list_for_each_entry(instance, &tz->thermal_instances, tz_node) {72 if (instance->trip != trip)73 continue;74 75 total_weight += instance->weight;76 nr_instances++;77 }78 79 list_for_each_entry(instance, &tz->thermal_instances, tz_node) {80 struct thermal_cooling_device *cdev = instance->cdev;81 u64 dividend;82 u32 divisor;83 84 if (instance->trip != trip)85 continue;86 87 dividend = trip_level;88 dividend *= cdev->max_state;89 divisor = tz->num_trips;90 if (total_weight) {91 dividend *= instance->weight;92 divisor *= total_weight;93 } else {94 divisor *= nr_instances;95 }96 instance->target = div_u64(dividend, divisor);97 98 mutex_lock(&cdev->lock);99 __thermal_cdev_update(cdev);100 mutex_unlock(&cdev->lock);101 }102}103 104static void fair_share_manage(struct thermal_zone_device *tz)105{106 int trip_level = get_trip_level(tz);107 const struct thermal_trip_desc *td;108 109 lockdep_assert_held(&tz->lock);110 111 for_each_trip_desc(tz, td) {112 const struct thermal_trip *trip = &td->trip;113 114 if (trip->temperature == THERMAL_TEMP_INVALID ||115 trip->type == THERMAL_TRIP_CRITICAL ||116 trip->type == THERMAL_TRIP_HOT)117 continue;118 119 fair_share_throttle(tz, trip, trip_level);120 }121}122 123static struct thermal_governor thermal_gov_fair_share = {124 .name = "fair_share",125 .manage = fair_share_manage,126};127THERMAL_GOVERNOR_DECLARE(thermal_gov_fair_share);128