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c408b3d1d9
In cur_state_store(), the new state of the cooling device is received from user-space and is not validated by the thermal core but the same is left for the individual drivers to take care of. Apart from duplicating the code it leaves possibility for introducing bugs where a driver may not do it right. Lets make the thermal core check the new state itself and store the max value in the cooling device structure. Link: https://lore.kernel.org/all/Y0ltRJRjO7AkawvE@kili/ Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
118 lines
3.2 KiB
C
118 lines
3.2 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 <trace/events/thermal.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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int count = 0;
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int trip_temp;
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enum thermal_trip_type trip_type;
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if (tz->num_trips == 0 || !tz->ops->get_trip_temp)
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return 0;
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for (count = 0; count < tz->num_trips; count++) {
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tz->ops->get_trip_temp(tz, count, &trip_temp);
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if (tz->temperature < trip_temp)
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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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tz->ops->get_trip_type(tz, count - 1, &trip_type);
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trace_thermal_zone_trip(tz, count - 1, trip_type);
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}
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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: 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)
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{
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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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