Release 4.14 drivers/thermal/clock_cooling.c
/*
* 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_IDA(clock_ida);
/* 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;
}
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/**
* 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;
}
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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;
}
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/**
* 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;
}
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/**
* 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;
}
}
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/* 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;
}
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/**
* 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;
}
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/**
* 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);
}
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/* 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);
mutex_init(&ccdev->lock);
ccdev->dev = dev;
ccdev->clk = devm_clk_get(dev, clock_name);
if (IS_ERR(ccdev->clk))
return ERR_CAST(ccdev->clk);
ret = ida_simple_get(&clock_ida, 0, 0, GFP_KERNEL);
if (ret < 0)
return ERR_PTR(ret);
ccdev->id = ret;
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)) {
ida_simple_remove(&clock_ida, 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) {
ida_simple_remove(&clock_ida, 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;
}
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| Eduardo Valentin | 243 | 88.04% | 1 | 33.33% |
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| Total | 276 | 100.00% | 3 | 100.00% |
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);
ida_simple_remove(&clock_ida, ccdev->id);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Eduardo Valentin | 64 | 94.12% | 1 | 50.00% |
| Matthew Wilcox | 4 | 5.88% | 1 | 50.00% |
| Total | 68 | 100.00% | 2 | 100.00% |
EXPORT_SYMBOL_GPL(clock_cooling_unregister);
Overall Contributors
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| Eduardo Valentin | 1137 | 96.68% | 1 | 33.33% |
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| Total | 1176 | 100.00% | 3 | 100.00% |
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