a4c428e523
The cpu idle cooling device offers a new method to cool down a CPU by injecting idle cycles at runtime. It has some similarities with the intel power clamp driver but it is actually designed to be more generic and relying on the idle injection powercap framework. The idle injection duration is fixed while the running duration is variable. That allows to have control on the device reactivity for the user experience. An idle state powering down the CPU or the cluster will allow to drop the static leakage, thus restoring the heat capacity of the SoC. It can be set with a trip point between the hot and the critical points, giving the opportunity to prevent a hard reset of the system when the cpufreq cooling fails to cool down the CPU. With more sophisticated boards having a per core sensor, the idle cooling device allows to cool down a single core without throttling the compute capacity of several cpus belonging to the same clock line, so it could be used in collaboration with the cpufreq cooling device. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lore.kernel.org/r/20191219225317.17158-2-daniel.lezcano@linaro.org
82 lines
2.1 KiB
C
82 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* linux/include/linux/cpu_cooling.h
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*
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* Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
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* Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org>
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*/
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#ifndef __CPU_COOLING_H__
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#define __CPU_COOLING_H__
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#include <linux/of.h>
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#include <linux/thermal.h>
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#include <linux/cpumask.h>
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struct cpufreq_policy;
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#ifdef CONFIG_CPU_FREQ_THERMAL
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/**
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* cpufreq_cooling_register - function to create cpufreq cooling device.
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* @policy: cpufreq policy.
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*/
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struct thermal_cooling_device *
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cpufreq_cooling_register(struct cpufreq_policy *policy);
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/**
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* cpufreq_cooling_unregister - function to remove cpufreq cooling device.
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* @cdev: thermal cooling device pointer.
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*/
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void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev);
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/**
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* of_cpufreq_cooling_register - create cpufreq cooling device based on DT.
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* @policy: cpufreq policy.
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*/
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struct thermal_cooling_device *
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of_cpufreq_cooling_register(struct cpufreq_policy *policy);
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#else /* !CONFIG_CPU_FREQ_THERMAL */
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static inline struct thermal_cooling_device *
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cpufreq_cooling_register(struct cpufreq_policy *policy)
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{
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return ERR_PTR(-ENOSYS);
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}
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static inline
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void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
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{
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return;
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}
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static inline struct thermal_cooling_device *
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of_cpufreq_cooling_register(struct cpufreq_policy *policy)
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{
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return NULL;
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}
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#endif /* CONFIG_CPU_FREQ_THERMAL */
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struct cpuidle_driver;
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#ifdef CONFIG_CPU_IDLE_THERMAL
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int cpuidle_cooling_register(struct cpuidle_driver *drv);
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int cpuidle_of_cooling_register(struct device_node *np,
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struct cpuidle_driver *drv);
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#else /* CONFIG_CPU_IDLE_THERMAL */
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static inline int cpuidle_cooling_register(struct cpuidle_driver *drv)
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{
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return 0;
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}
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static inline int cpuidle_of_cooling_register(struct device_node *np,
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struct cpuidle_driver *drv)
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{
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return 0;
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}
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#endif /* CONFIG_CPU_IDLE_THERMAL */
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#endif /* __CPU_COOLING_H__ */
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