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8c35b1f472
Modify the governor .throttle() callback definition so that it takes a trip pointer instead of a trip index as its second argument, adjust the governors accordingly and update the core code invoking .throttle(). This causes the governors to become independent of the representation of the list of trips in the thermal zone structure. This change is not expected to alter the general functionality. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
115 lines
3.3 KiB
C
115 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* gov_bang_bang.c - A simple thermal throttling governor using hysteresis
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*
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* Copyright (C) 2014 Peter Kaestle <peter@piie.net>
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*
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* Based on step_wise.c with following Copyrights:
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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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#include <linux/thermal.h>
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#include "thermal_core.h"
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static int thermal_zone_trip_update(struct thermal_zone_device *tz,
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const struct thermal_trip *trip)
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{
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int trip_index = thermal_zone_trip_id(tz, trip);
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struct thermal_instance *instance;
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if (!trip->hysteresis)
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dev_info_once(&tz->device,
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"Zero hysteresis value for thermal zone %s\n", tz->type);
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dev_dbg(&tz->device, "Trip%d[temp=%d]:temp=%d:hyst=%d\n",
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trip_index, trip->temperature, tz->temperature,
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trip->hysteresis);
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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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/* in case fan is in initial state, switch the fan off */
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if (instance->target == THERMAL_NO_TARGET)
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instance->target = 0;
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/* in case fan is neither on nor off set the fan to active */
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if (instance->target != 0 && instance->target != 1) {
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pr_warn("Thermal instance %s controlled by bang-bang has unexpected state: %ld\n",
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instance->name, instance->target);
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instance->target = 1;
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}
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/*
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* enable fan when temperature exceeds trip_temp and disable
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* the fan in case it falls below trip_temp minus hysteresis
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*/
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if (instance->target == 0 && tz->temperature >= trip->temperature)
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instance->target = 1;
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else if (instance->target == 1 &&
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tz->temperature <= trip->temperature - trip->hysteresis)
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instance->target = 0;
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dev_dbg(&instance->cdev->device, "target=%d\n",
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(int)instance->target);
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mutex_lock(&instance->cdev->lock);
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instance->cdev->updated = false; /* cdev needs update */
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mutex_unlock(&instance->cdev->lock);
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}
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return 0;
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}
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/**
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* bang_bang_control - controls devices associated with the given zone
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* @tz: thermal_zone_device
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* @trip: the trip point
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*
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* Regulation Logic: a two point regulation, deliver cooling state depending
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* on the previous state shown in this diagram:
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*
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* Fan: OFF ON
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*
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* |
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* |
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* trip_temp: +---->+
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* | | ^
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* | | |
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* | | Temperature
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* (trip_temp - hyst): +<----+
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* |
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* |
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* |
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*
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* * If the fan is not running and temperature exceeds trip_temp, the fan
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* gets turned on.
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* * In case the fan is running, temperature must fall below
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* (trip_temp - hyst) so that the fan gets turned off again.
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*
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*/
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static int bang_bang_control(struct thermal_zone_device *tz,
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const struct thermal_trip *trip)
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{
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struct thermal_instance *instance;
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int ret;
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lockdep_assert_held(&tz->lock);
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ret = thermal_zone_trip_update(tz, trip);
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if (ret)
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return ret;
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list_for_each_entry(instance, &tz->thermal_instances, tz_node)
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thermal_cdev_update(instance->cdev);
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return 0;
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}
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static struct thermal_governor thermal_gov_bang_bang = {
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.name = "bang_bang",
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.throttle = bang_bang_control,
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};
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THERMAL_GOVERNOR_DECLARE(thermal_gov_bang_bang);
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