114 lines
3.1 KiB
C
114 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* fair_share.c - A simple weight based Thermal governor
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*
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* Copyright (C) 2012 Intel Corp
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* Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com>
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*/
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#include <linux/thermal.h>
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#include "thermal_trace.h"
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#include "thermal_core.h"
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/**
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* get_trip_level: - obtains the current trip level for a zone
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* @tz: thermal zone device
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*/
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static int get_trip_level(struct thermal_zone_device *tz)
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{
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struct thermal_trip trip;
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int count;
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for (count = 0; count < tz->num_trips; count++) {
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__thermal_zone_get_trip(tz, count, &trip);
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if (tz->temperature < trip.temperature)
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break;
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}
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/*
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* count > 0 only if temperature is greater than first trip
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* point, in which case, trip_point = count - 1
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*/
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if (count > 0)
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trace_thermal_zone_trip(tz, count - 1, trip.type);
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return count;
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}
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static long get_target_state(struct thermal_zone_device *tz,
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struct thermal_cooling_device *cdev, int percentage, int level)
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{
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return (long)(percentage * level * cdev->max_state) / (100 * tz->num_trips);
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}
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/**
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* fair_share_throttle - throttles devices associated with the given zone
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* @tz: thermal_zone_device
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* @trip_index: trip point index
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*
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* Throttling Logic: This uses three parameters to calculate the new
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* throttle state of the cooling devices associated with the given zone.
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*
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* Parameters used for Throttling:
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* P1. max_state: Maximum throttle state exposed by the cooling device.
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* P2. percentage[i]/100:
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* How 'effective' the 'i'th device is, in cooling the given zone.
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* P3. cur_trip_level/max_no_of_trips:
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* This describes the extent to which the devices should be throttled.
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* We do not want to throttle too much when we trip a lower temperature,
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* whereas the throttling is at full swing if we trip critical levels.
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* (Heavily assumes the trip points are in ascending order)
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* new_state of cooling device = P3 * P2 * P1
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*/
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static int fair_share_throttle(struct thermal_zone_device *tz, int trip_index)
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{
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const struct thermal_trip *trip = &tz->trips[trip_index];
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struct thermal_instance *instance;
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int total_weight = 0;
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int total_instance = 0;
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int cur_trip_level = get_trip_level(tz);
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lockdep_assert_held(&tz->lock);
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list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
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if (instance->trip != trip)
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continue;
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total_weight += instance->weight;
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total_instance++;
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}
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list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
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int percentage;
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struct thermal_cooling_device *cdev = instance->cdev;
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if (instance->trip != trip)
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continue;
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if (!total_weight)
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percentage = 100 / total_instance;
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else
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percentage = (instance->weight * 100) / total_weight;
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instance->target = get_target_state(tz, cdev, percentage,
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cur_trip_level);
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mutex_lock(&cdev->lock);
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__thermal_cdev_update(cdev);
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mutex_unlock(&cdev->lock);
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}
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return 0;
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}
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static struct thermal_governor thermal_gov_fair_share = {
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.name = "fair_share",
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.throttle = fair_share_throttle,
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};
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THERMAL_GOVERNOR_DECLARE(thermal_gov_fair_share);
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