thermal: introduce clock cooling device (f9df89d8) · Commits · 戴 / test

drivers/thermal/Kconfig

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		@@ -112,6 +112,18 @@ config CPU_THERMAL

		If you want this support, you should say Y here.

		config CLOCK_THERMAL
		bool "Generic clock cooling support"
		depends on COMMON_CLK
		depends on PM_OPP
		help
		This entry implements the generic clock cooling mechanism through
		frequency clipping. Typically used to cool off co-processors. The
		device that is configured to use this cooling mechanism will be
		controlled to reduce clock frequency whenever temperature is high.

		If you want this support, you should say Y here.

		config THERMAL_EMULATION
		bool "Thermal emulation mode support"
		help

drivers/thermal/Makefile

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		@@ -18,6 +18,9 @@ thermal_sys-$(CONFIG_THERMAL_GOV_USER_SPACE) += user_space.o
		# cpufreq cooling
		thermal_sys-$(CONFIG_CPU_THERMAL) += cpu_cooling.o

		# clock cooling
		thermal_sys-$(CONFIG_CLOCK_THERMAL) += clock_cooling.o

		# platform thermal drivers
		obj-$(CONFIG_SPEAR_THERMAL) += spear_thermal.o
		obj-$(CONFIG_RCAR_THERMAL) += rcar_thermal.o

drivers/thermal/clock_cooling.c

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		/*
		* drivers/thermal/clock_cooling.c
		*
		* Copyright (C) 2014 Eduardo Valentin <edubezval@gmail.com>
		*
		* Copyright (C) 2013 Texas Instruments Inc.
		* Contact: Eduardo Valentin <eduardo.valentin@ti.com>
		*
		* Highly based on cpu_cooling.c.
		* Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
		* Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; version 2 of the License.
		*
		* This program is distributed in the hope that it will be useful, but
		* WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
		* General Public License for more details.
		*/
		#include <linux/clk.h>
		#include <linux/cpufreq.h>
		#include <linux/device.h>
		#include <linux/err.h>
		#include <linux/idr.h>
		#include <linux/mutex.h>
		#include <linux/pm_opp.h>
		#include <linux/slab.h>
		#include <linux/thermal.h>
		#include <linux/clock_cooling.h>

		/**
		* struct clock_cooling_device - data for cooling device with clock
		* @id: unique integer value corresponding to each clock_cooling_device
		* registered.
		* @dev: struct device pointer to the device being used to cool off using
		* clock frequencies.
		* @cdev: thermal_cooling_device pointer to keep track of the
		* registered cooling device.
		* @clk_rate_change_nb: reference to notifier block used to receive clock
		* rate changes.
		* @freq_table: frequency table used to keep track of available frequencies.
		* @clock_state: integer value representing the current state of clock
		* cooling devices.
		* @clock_val: integer value representing the absolute value of the clipped
		* frequency.
		* @clk: struct clk reference used to enforce clock limits.
		* @lock: mutex lock to protect this struct.
		*
		* This structure is required for keeping information of each
		* clock_cooling_device registered. In order to prevent corruption of this a
		* mutex @lock is used.
		*/
		struct clock_cooling_device {
		int id;
		struct device *dev;
		struct thermal_cooling_device *cdev;
		struct notifier_block clk_rate_change_nb;
		struct cpufreq_frequency_table *freq_table;
		unsigned long clock_state;
		unsigned long clock_val;
		struct clk *clk;
		struct mutex lock; /* lock to protect the content of this struct */
		};
		#define to_clock_cooling_device(x) \
		container_of(x, struct clock_cooling_device, clk_rate_change_nb)
		static DEFINE_IDR(clock_idr);
		static DEFINE_MUTEX(cooling_clock_lock);

		/**
		* clock_cooling_get_idr - function to get an unique id.
		* @id: int * value generated by this function.
		*
		* This function will populate @id with an unique
		* id, using the idr API.
		*
		* Return: 0 on success, an error code on failure.
		*/
		static int clock_cooling_get_idr(int *id)
		{
		int ret;

		mutex_lock(&cooling_clock_lock);
		ret = idr_alloc(&clock_idr, NULL, 0, 0, GFP_KERNEL);
		mutex_unlock(&cooling_clock_lock);
		if (unlikely(ret < 0))
		return ret;
		*id = ret;

		return 0;
		}

		/**
		* release_idr - function to free the unique id.
		* @id: int value representing the unique id.
		*/
		static void release_idr(int id)
		{
		mutex_lock(&cooling_clock_lock);
		idr_remove(&clock_idr, id);
		mutex_unlock(&cooling_clock_lock);
		}

		/* Below code defines functions to be used for clock as cooling device */

		enum clock_cooling_property {
		GET_LEVEL,
		GET_FREQ,
		GET_MAXL,
		};

		/**
		* clock_cooling_get_property - fetch a property of interest for a give cpu.
		* @ccdev: clock cooling device reference
		* @input: query parameter
		* @output: query return
		* @property: type of query (frequency, level, max level)
		*
		* This is the common function to
		* 1. get maximum clock cooling states
		* 2. translate frequency to cooling state
		* 3. translate cooling state to frequency
		* Note that the code may be not in good shape
		* but it is written in this way in order to:
		* a) reduce duplicate code as most of the code can be shared.
		* b) make sure the logic is consistent when translating between
		* cooling states and frequencies.
		*
		* Return: 0 on success, -EINVAL when invalid parameters are passed.
		*/
		static int clock_cooling_get_property(struct clock_cooling_device *ccdev,
		unsigned long input,
		unsigned long *output,
		enum clock_cooling_property property)
		{
		int i;
		unsigned long max_level = 0, level = 0;
		unsigned int freq = CPUFREQ_ENTRY_INVALID;
		int descend = -1;
		struct cpufreq_frequency_table pos, table = ccdev->freq_table;

		if (!output)
		return -EINVAL;

		if (!table)
		return -EINVAL;

		cpufreq_for_each_valid_entry(pos, table) {
		/* ignore duplicate entry */
		if (freq == pos->frequency)
		continue;

		/* get the frequency order */
		if (freq != CPUFREQ_ENTRY_INVALID && descend == -1)
		descend = freq > pos->frequency;

		freq = pos->frequency;
		max_level++;
		}

		/* No valid cpu frequency entry */
		if (max_level == 0)
		return -EINVAL;

		/* max_level is an index, not a counter */
		max_level--;

		/* get max level */
		if (property == GET_MAXL) {
		*output = max_level;
		return 0;
		}

		if (property == GET_FREQ)
		level = descend ? input : (max_level - input);

		i = 0;
		cpufreq_for_each_valid_entry(pos, table) {
		/* ignore duplicate entry */
		if (freq == pos->frequency)
		continue;

		/* now we have a valid frequency entry */
		freq = pos->frequency;

		if (property == GET_LEVEL && (unsigned int)input == freq) {
		/* get level by frequency */
		*output = descend ? i : (max_level - i);
		return 0;
		}
		if (property == GET_FREQ && level == i) {
		/* get frequency by level */
		*output = freq;
		return 0;
		}
		i++;
		}

		return -EINVAL;
		}

		/**
		* clock_cooling_get_level - return the cooling level of given clock cooling.
		* @cdev: reference of a thermal cooling device of used as clock cooling device
		* @freq: the frequency of interest
		*
		* This function will match the cooling level corresponding to the
		* requested @freq and return it.
		*
		* Return: The matched cooling level on success or THERMAL_CSTATE_INVALID
		* otherwise.
		*/
		unsigned long clock_cooling_get_level(struct thermal_cooling_device *cdev,
		unsigned long freq)
		{
		struct clock_cooling_device *ccdev = cdev->devdata;
		unsigned long val;

		if (clock_cooling_get_property(ccdev, (unsigned long)freq, &val,
		GET_LEVEL))
		return THERMAL_CSTATE_INVALID;

		return val;
		}
		EXPORT_SYMBOL_GPL(clock_cooling_get_level);

		/**
		* clock_cooling_get_frequency - get the absolute value of frequency from level.
		* @ccdev: clock cooling device reference
		* @level: cooling level
		*
		* This function matches cooling level with frequency. Based on a cooling level
		* of frequency, equals cooling state of cpu cooling device, it will return
		* the corresponding frequency.
		* e.g level=0 --> 1st MAX FREQ, level=1 ---> 2nd MAX FREQ, .... etc
		*
		* Return: 0 on error, the corresponding frequency otherwise.
		*/
		static unsigned long
		clock_cooling_get_frequency(struct clock_cooling_device *ccdev,
		unsigned long level)
		{
		int ret = 0;
		unsigned long freq;

		ret = clock_cooling_get_property(ccdev, level, &freq, GET_FREQ);
		if (ret)
		return 0;

		return freq;
		}

		/**
		* clock_cooling_apply - function to apply frequency clipping.
		* @ccdev: clock_cooling_device pointer containing frequency clipping data.
		* @cooling_state: value of the cooling state.
		*
		* Function used to make sure the clock layer is aware of current thermal
		* limits. The limits are applied by updating the clock rate in case it is
		* higher than the corresponding frequency based on the requested cooling_state.
		*
		* Return: 0 on success, an error code otherwise (-EINVAL in case wrong
		* cooling state).
		*/
		static int clock_cooling_apply(struct clock_cooling_device *ccdev,
		unsigned long cooling_state)
		{
		unsigned long clip_freq, cur_freq;
		int ret = 0;

		/* Here we write the clipping */
		/* Check if the old cooling action is same as new cooling action */
		if (ccdev->clock_state == cooling_state)
		return 0;

		clip_freq = clock_cooling_get_frequency(ccdev, cooling_state);
		if (!clip_freq)
		return -EINVAL;

		cur_freq = clk_get_rate(ccdev->clk);

		mutex_lock(&ccdev->lock);
		ccdev->clock_state = cooling_state;
		ccdev->clock_val = clip_freq;
		/* enforce clock level */
		if (cur_freq > clip_freq)
		ret = clk_set_rate(ccdev->clk, clip_freq);
		mutex_unlock(&ccdev->lock);

		return ret;
		}

		/**
		* clock_cooling_clock_notifier - notifier callback on clock rate changes.
		* @nb: struct notifier_block * with callback info.
		* @event: value showing clock event for which this function invoked.
		* @data: callback-specific data
		*
		* Callback to hijack the notification on clock transition.
		* Every time there is a clock change, we intercept all pre change events
		* and block the transition in case the new rate infringes thermal limits.
		*
		* Return: NOTIFY_DONE (success) or NOTIFY_BAD (new_rate > thermal limit).
		*/
		static int clock_cooling_clock_notifier(struct notifier_block *nb,
		unsigned long event, void *data)
		{
		struct clk_notifier_data *ndata = data;
		struct clock_cooling_device *ccdev = to_clock_cooling_device(nb);

		switch (event) {
		case PRE_RATE_CHANGE:
		/*
		* checks on current state
		* TODO: current method is not best we can find as it
		* allows possibly voltage transitions, in case DVFS
		* layer is also hijacking clock pre notifications.
		*/
		if (ndata->new_rate > ccdev->clock_val)
		return NOTIFY_BAD;
		/* fall through */
		case POST_RATE_CHANGE:
		case ABORT_RATE_CHANGE:
		default:
		return NOTIFY_DONE;
		}
		}

		/* clock cooling device thermal callback functions are defined below */

		/**
		* clock_cooling_get_max_state - callback function to get the max cooling state.
		* @cdev: thermal cooling device pointer.
		* @state: fill this variable with the max cooling state.
		*
		* Callback for the thermal cooling device to return the clock
		* max cooling state.
		*
		* Return: 0 on success, an error code otherwise.
		*/
		static int clock_cooling_get_max_state(struct thermal_cooling_device *cdev,
		unsigned long *state)
		{
		struct clock_cooling_device *ccdev = cdev->devdata;
		unsigned long count = 0;
		int ret;

		ret = clock_cooling_get_property(ccdev, 0, &count, GET_MAXL);
		if (!ret)
		*state = count;

		return ret;
		}

		/**
		* clock_cooling_get_cur_state - function to get the current cooling state.
		* @cdev: thermal cooling device pointer.
		* @state: fill this variable with the current cooling state.
		*
		* Callback for the thermal cooling device to return the clock
		* current cooling state.
		*
		* Return: 0 (success)
		*/
		static int clock_cooling_get_cur_state(struct thermal_cooling_device *cdev,
		unsigned long *state)
		{
		struct clock_cooling_device *ccdev = cdev->devdata;

		*state = ccdev->clock_state;

		return 0;
		}

		/**
		* clock_cooling_set_cur_state - function to set the current cooling state.
		* @cdev: thermal cooling device pointer.
		* @state: set this variable to the current cooling state.
		*
		* Callback for the thermal cooling device to change the clock cooling
		* current cooling state.
		*
		* Return: 0 on success, an error code otherwise.
		*/
		static int clock_cooling_set_cur_state(struct thermal_cooling_device *cdev,
		unsigned long state)
		{
		struct clock_cooling_device *clock_device = cdev->devdata;

		return clock_cooling_apply(clock_device, state);
		}

		/* Bind clock callbacks to thermal cooling device ops */
		static struct thermal_cooling_device_ops const clock_cooling_ops = {
		.get_max_state = clock_cooling_get_max_state,
		.get_cur_state = clock_cooling_get_cur_state,
		.set_cur_state = clock_cooling_set_cur_state,
		};

		/**
		* clock_cooling_register - function to create clock cooling device.
		* @dev: struct device pointer to the device used as clock cooling device.
		* @clock_name: string containing the clock used as cooling mechanism.
		*
		* This interface function registers the clock cooling device with the name
		* "thermal-clock-%x". The cooling device is based on clock frequencies.
		* The struct device is assumed to be capable of DVFS transitions.
		* The OPP layer is used to fetch and fill the available frequencies for
		* the referred device. The ordered frequency table is used to control
		* the clock cooling device cooling states and to limit clock transitions
		* based on the cooling state requested by the thermal framework.
		*
		* Return: a valid struct thermal_cooling_device pointer on success,
		* on failure, it returns a corresponding ERR_PTR().
		*/
		struct thermal_cooling_device *
		clock_cooling_register(struct device dev, const char clock_name)
		{
		struct thermal_cooling_device *cdev;
		struct clock_cooling_device *ccdev = NULL;
		char dev_name[THERMAL_NAME_LENGTH];
		int ret = 0;

		ccdev = devm_kzalloc(dev, sizeof(*ccdev), GFP_KERNEL);
		if (!ccdev)
		return ERR_PTR(-ENOMEM);

		ccdev->dev = dev;
		ccdev->clk = devm_clk_get(dev, clock_name);
		if (IS_ERR(ccdev->clk))
		return ERR_CAST(ccdev->clk);

		ret = clock_cooling_get_idr(&ccdev->id);
		if (ret)
		return ERR_PTR(-EINVAL);

		snprintf(dev_name, sizeof(dev_name), "thermal-clock-%d", ccdev->id);

		cdev = thermal_cooling_device_register(dev_name, ccdev,
		&clock_cooling_ops);
		if (IS_ERR(cdev)) {
		release_idr(ccdev->id);
		return ERR_PTR(-EINVAL);
		}
		ccdev->cdev = cdev;
		ccdev->clk_rate_change_nb.notifier_call = clock_cooling_clock_notifier;

		/* Assuming someone has already filled the opp table for this device */
		ret = dev_pm_opp_init_cpufreq_table(dev, &ccdev->freq_table);
		if (ret) {
		release_idr(ccdev->id);
		return ERR_PTR(ret);
		}
		ccdev->clock_state = 0;
		ccdev->clock_val = clock_cooling_get_frequency(ccdev, 0);

		clk_notifier_register(ccdev->clk, &ccdev->clk_rate_change_nb);

		return cdev;
		}
		EXPORT_SYMBOL_GPL(clock_cooling_register);

		/**
		* clock_cooling_unregister - function to remove clock cooling device.
		* @cdev: thermal cooling device pointer.
		*
		* This interface function unregisters the "thermal-clock-%x" cooling device.
		*/
		void clock_cooling_unregister(struct thermal_cooling_device *cdev)
		{
		struct clock_cooling_device *ccdev;

		if (!cdev)
		return;

		ccdev = cdev->devdata;

		clk_notifier_unregister(ccdev->clk, &ccdev->clk_rate_change_nb);
		dev_pm_opp_free_cpufreq_table(ccdev->dev, &ccdev->freq_table);

		thermal_cooling_device_unregister(ccdev->cdev);
		release_idr(ccdev->id);
		}
		EXPORT_SYMBOL_GPL(clock_cooling_unregister);

include/linux/clock_cooling.h

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		/*
		* linux/include/linux/clock_cooling.h
		*
		* Copyright (C) 2014 Eduardo Valentin <edubezval@gmail.com>
		*
		* Copyright (C) 2013 Texas Instruments Inc.
		* Contact: Eduardo Valentin <eduardo.valentin@ti.com>
		*
		* Highly based on cpu_cooling.c.
		* Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
		* Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; version 2 of the License.
		*
		* This program is distributed in the hope that it will be useful, but
		* WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
		* General Public License for more details.
		*/

		#ifndef __CPU_COOLING_H__
		#define __CPU_COOLING_H__

		#include <linux/of.h>
		#include <linux/thermal.h>
		#include <linux/cpumask.h>

		#ifdef CONFIG_CLOCK_THERMAL
		/**
		* clock_cooling_register - function to create clock cooling device.
		* @dev: struct device pointer to the device used as clock cooling device.
		* @clock_name: string containing the clock used as cooling mechanism.
		*/
		struct thermal_cooling_device *
		clock_cooling_register(struct device dev, const char clock_name);

		/**
		* clock_cooling_unregister - function to remove clock cooling device.
		* @cdev: thermal cooling device pointer.
		*/
		void clock_cooling_unregister(struct thermal_cooling_device *cdev);

		unsigned long clock_cooling_get_level(struct thermal_cooling_device *cdev,
		unsigned long freq);
		#else /* !CONFIG_CLOCK_THERMAL */
		static inline struct thermal_cooling_device *
		clock_cooling_register(struct device dev, const char clock_name)
		{
		return NULL;
		}
		static inline
		void clock_cooling_unregister(struct thermal_cooling_device *cdev)
		{
		}
		static inline
		unsigned long clock_cooling_get_level(struct thermal_cooling_device *cdev,
		unsigned long freq)
		{
		return THERMAL_CSTATE_INVALID;
		}
		#endif /* CONFIG_CLOCK_THERMAL */

		#endif /* __CPU_COOLING_H__ */

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