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If a cooling device is registered after a thermal zone it should be
bound to and the trip point it should be bound to has already been
crossed by the zone temperature on the way up, the cooling device's
state may need to be adjusted, but the Bang-bang governor will not
do that because its .manage() callback only looks at thermal instances
for trip points whose thresholds are below or at the zone temperature.
Address this by updating bang_bang_manage() to look at all of the
uninitialized thermal instances and setting their target states in
accordance with the position of the zone temperature with respect to
the threshold of the given trip point.
Fixes: 5f64b4a1ab ("thermal: gov_bang_bang: Add .manage() callback")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/6103874.lOV4Wx5bFT@rjwysocki.net
134 lines
3.9 KiB
C
134 lines
3.9 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 void bang_bang_set_instance_target(struct thermal_instance *instance,
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unsigned int target)
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{
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if (instance->target != 0 && instance->target != 1 &&
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instance->target != THERMAL_NO_TARGET)
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pr_debug("Unexpected state %ld of thermal instance %s in bang-bang\n",
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instance->target, instance->name);
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/*
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* Enable the fan when the trip is crossed on the way up and disable it
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* when the trip is crossed on the way down.
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*/
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instance->target = target;
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instance->initialized = true;
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dev_dbg(&instance->cdev->device, "target=%ld\n", instance->target);
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mutex_lock(&instance->cdev->lock);
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__thermal_cdev_update(instance->cdev);
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mutex_unlock(&instance->cdev->lock);
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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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* @crossed_up: whether or not the trip has been crossed on the way up
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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 void bang_bang_control(struct thermal_zone_device *tz,
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const struct thermal_trip *trip,
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bool crossed_up)
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{
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struct thermal_instance *instance;
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lockdep_assert_held(&tz->lock);
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dev_dbg(&tz->device, "Trip%d[temp=%d]:temp=%d:hyst=%d\n",
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thermal_zone_trip_id(tz, trip), trip->temperature,
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tz->temperature, 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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bang_bang_set_instance_target(instance, crossed_up);
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}
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}
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static void bang_bang_manage(struct thermal_zone_device *tz)
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{
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const struct thermal_trip_desc *td;
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struct thermal_instance *instance;
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/* If the code below has run already, nothing needs to be done. */
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if (tz->governor_data)
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return;
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for_each_trip_desc(tz, td) {
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const struct thermal_trip *trip = &td->trip;
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bool turn_on;
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if (trip->temperature == THERMAL_TEMP_INVALID ||
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trip->type == THERMAL_TRIP_CRITICAL ||
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trip->type == THERMAL_TRIP_HOT)
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continue;
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/*
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* Adjust the target states for uninitialized thermal instances
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* to the thermal zone temperature and the trip point threshold.
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*/
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turn_on = tz->temperature >= td->threshold;
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list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
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if (!instance->initialized && instance->trip == trip)
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bang_bang_set_instance_target(instance, turn_on);
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}
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}
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tz->governor_data = (void *)true;
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}
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static void bang_bang_update_tz(struct thermal_zone_device *tz,
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enum thermal_notify_event reason)
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{
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/*
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* Let bang_bang_manage() know that it needs to walk trips after binding
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* a new cdev and after system resume.
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*/
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if (reason == THERMAL_TZ_BIND_CDEV || reason == THERMAL_TZ_RESUME)
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tz->governor_data = NULL;
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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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.trip_crossed = bang_bang_control,
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.manage = bang_bang_manage,
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.update_tz = bang_bang_update_tz,
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};
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THERMAL_GOVERNOR_DECLARE(thermal_gov_bang_bang);
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