| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * fair_share.c - A simple weight based Thermal governor |
| * |
| * Copyright (C) 2012 Intel Corp |
| * Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com> |
| * |
| * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| * |
| * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| */ |
| |
| #include <linux/thermal.h> |
| #include "thermal_trace.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) |
| { |
| struct thermal_trip trip; |
| int count; |
| |
| for (count = 0; count < tz->num_trips; count++) { |
| __thermal_zone_get_trip(tz, count, &trip); |
| if (tz->temperature < trip.temperature) |
| break; |
| } |
| |
| /* |
| * count > 0 only if temperature is greater than first trip |
| * point, in which case, trip_point = count - 1 |
| */ |
| if (count > 0) |
| 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) |
| { |
| return (long)(percentage * level * cdev->max_state) / (100 * tz->num_trips); |
| } |
| |
| /** |
| * fair_share_throttle - throttles devices associated with the given zone |
| * @tz: thermal_zone_device |
| * @trip_index: trip point index |
| * |
| * 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_index) |
| { |
| const struct thermal_trip *trip = &tz->trips[trip_index]; |
| struct thermal_instance *instance; |
| int total_weight = 0; |
| int total_instance = 0; |
| int cur_trip_level = get_trip_level(tz); |
| |
| lockdep_assert_held(&tz->lock); |
| |
| 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(&cdev->lock); |
| __thermal_cdev_update(cdev); |
| mutex_unlock(&cdev->lock); |
| } |
| |
| return 0; |
| } |
| |
| static struct thermal_governor thermal_gov_fair_share = { |
| .name = "fair_share", |
| .throttle = fair_share_throttle, |
| }; |
| THERMAL_GOVERNOR_DECLARE(thermal_gov_fair_share); |