/*
* linux/drivers/thermal/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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/module.h>
#include <linux/thermal.h>
#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/cpu_cooling.h>
/*
* Cooling state <-> CPUFreq frequency
*
* Cooling states are translated to frequencies throughout this driver and this
* is the relation between them.
*
* Highest cooling state corresponds to lowest possible frequency.
*
* i.e.
* level 0 --> 1st Max Freq
* level 1 --> 2nd Max Freq
* ...
*/
/**
* struct cpufreq_cooling_device - data for cooling device with cpufreq
* @id: unique integer value corresponding to each cpufreq_cooling_device
* registered.
* @cool_dev: thermal_cooling_device pointer to keep track of the
* registered cooling device.
* @cpufreq_state: integer value representing the current state of cpufreq
* cooling devices.
* @cpufreq_val: integer value representing the absolute value of the clipped
* frequency.
* @max_level: maximum cooling level. One less than total number of valid
* cpufreq frequencies.
* @allowed_cpus: all the cpus involved for this cpufreq_cooling_device.
*
* This structure is required for keeping information of each registered
* cpufreq_cooling_device.
*/
struct cpufreq_cooling_device {
int id;
struct thermal_cooling_device *cool_dev;
unsigned int cpufreq_state;
unsigned int cpufreq_val;
unsigned int max_level;
unsigned int *freq_table; /* In descending order */
struct cpumask allowed_cpus;
struct list_head node;
};
static DEFINE_IDR(cpufreq_idr);
static DEFINE_MUTEX(cooling_cpufreq_lock);
static LIST_HEAD(cpufreq_dev_list);
/**
* get_idr - function to get a unique id.
* @idr: struct idr * handle used to create a 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 get_idr(struct idr *idr, int *id)
{
int ret;
mutex_lock(&cooling_cpufreq_lock);
ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);
mutex_unlock(&cooling_cpufreq_lock);
if (unlikely(ret < 0))
return ret;
*id = ret;
return 0;
}
/**
* release_idr - function to free the unique id.
* @idr: struct idr * handle used for creating the id.
* @id: int value representing the unique id.
*/
static void release_idr(struct idr *idr, int id)
{
mutex_lock(&cooling_cpufreq_lock);
idr_remove(idr, id);
mutex_unlock(&cooling_cpufreq_lock);
}
/* Below code defines functions to be used for cpufreq as cooling device */
enum cpufreq_cooling_property {
GET_LEVEL,
GET_FREQ,
};
/**
* get_property - fetch a property of interest for a given cpu.
* @cpufreq_dev: cpufreq_dev for which the property is required
* @input: query parameter
* @output: query return
* @property: type of query (frequency, level)
*
* This is the common function to
* 1. translate frequency to cooling state
* 2. 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 get_property(struct cpufreq_cooling_device *cpufreq_dev,
unsigned long input, unsigned int *output,
enum cpufreq_cooling_property property)
{
int i;
unsigned long level = 0;
unsigned int freq = CPUFREQ_ENTRY_INVALID;
int descend = -1;
struct cpufreq_frequency_table *pos, *table;
if (!output)
return -EINVAL;
table = cpufreq_frequency_get_table(cpumask_first(&cpufreq_dev->allowed_cpus));
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;
}
if (property == GET_FREQ)
level = descend ? input : (cpufreq_dev->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 : (cpufreq_dev->max_level - i);
return 0;
}
if (property == GET_FREQ && level == i) {
/* get frequency by level */
*output = freq;
return 0;
}
i++;
}
return -EINVAL;
}
/**
* cpufreq_cooling_get_level - for a given cpu, return the cooling level.
* @cpu: cpu for which the level is required
* @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 cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq)
{
struct cpufreq_cooling_device *cpufreq_dev;
mutex_lock(&cooling_cpufreq_lock);
list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) {
if (cpumask_test_cpu(cpu, &cpufreq_dev->allowed_cpus)) {
unsigned int val;
mutex_unlock(&cooling_cpufreq_lock);
if (get_property(cpufreq_dev, (unsigned long)freq, &val,
GET_LEVEL))
return THERMAL_CSTATE_INVALID;
return (unsigned long)val;
}
}
mutex_unlock(&cooling_cpufreq_lock);
pr_err("%s: cpu:%d not part of any cooling device\n", __func__, cpu);
return THERMAL_CSTATE_INVALID;
}
EXPORT_SYMBOL_GPL(cpufreq_cooling_get_level);
/**
* cpufreq_thermal_notifier - notifier callback for cpufreq policy change.
* @nb: struct notifier_block * with callback info.
* @event: value showing cpufreq event for which this function invoked.
* @data: callback-specific data
*
* Callback to hijack the notification on cpufreq policy transition.
* Every time there is a change in policy, we will intercept and
* update the cpufreq policy with thermal constraints.
*
* Return: 0 (success)
*/
static int cpufreq_thermal_notifier(struct notifier_block *nb,
unsigned long event, void *data)
{
struct cpufreq_policy *policy = data;
unsigned long max_freq = 0;
struct cpufreq_cooling_device *cpufreq_dev;
if (event != CPUFREQ_ADJUST)
return 0;
mutex_lock(&cooling_cpufreq_lock);
list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) {
if (!cpumask_test_cpu(policy->cpu,
&cpufreq_dev->allowed_cpus))
continue;
max_freq = cpufreq_dev->cpufreq_val;
if (policy->max != max_freq)
cpufreq_verify_within_limits(policy, 0, max_freq);
}
mutex_unlock(&cooling_cpufreq_lock);
return 0;
}
/* cpufreq cooling device callback functions are defined below */
/**
* cpufreq_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 cpufreq
* max cooling state.
*
* Return: 0 on success, an error code otherwise.
*/
static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
*state = cpufreq_device->max_level;
return 0;
}
/**
* cpufreq_get_cur_state - callback 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 cpufreq
* current cooling state.
*
* Return: 0 on success, an error code otherwise.
*/
static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
*state = cpufreq_device->cpufreq_state;
return 0;
}
/**
* cpufreq_set_cur_state - callback 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 cpufreq
* current cooling state.
*
* Return: 0 on success, an error code otherwise.
*/
static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long state)
{
struct cpufreq_cooling_device *cpufreq_device = cdev->devdata;
unsigned int cpu = cpumask_any(&cpufreq_device->allowed_cpus);
unsigned int clip_freq;
int ret;
/* Check if the old cooling action is same as new cooling action */
if (cpufreq_device->cpufreq_state == state)
return 0;
ret = get_property(cpufreq_device, state, &clip_freq, GET_FREQ);
if (ret)
return ret;
cpufreq_device->cpufreq_state = state;
cpufreq_device->cpufreq_val = clip_freq;
cpufreq_update_policy(cpu);
return 0;
}
/* Bind cpufreq callbacks to thermal cooling device ops */
static struct thermal_cooling_device_ops const cpufreq_cooling_ops = {
.get_max_state = cpufreq_get_max_state,
.get_cur_state = cpufreq_get_cur_state,
.set_cur_state = cpufreq_set_cur_state,
};
/* Notifier for cpufreq policy change */
static struct notifier_block thermal_cpufreq_notifier_block = {
.notifier_call = cpufreq_thermal_notifier,
};
static unsigned int find_next_max(struct cpufreq_frequency_table *table,
unsigned int prev_max)
{
struct cpufreq_frequency_table *pos;
unsigned int max = 0;
cpufreq_for_each_valid_entry(pos, table) {
if (pos->frequency > max && pos->frequency < prev_max)
max = pos->frequency;
}
return max;
}
/**
* __cpufreq_cooling_register - helper function to create cpufreq cooling device
* @np: a valid struct device_node to the cooling device device tree node
* @clip_cpus: cpumask of cpus where the frequency constraints will happen.
* Normally this should be same as cpufreq policy->related_cpus.
*
* This interface function registers the cpufreq cooling device with the name
* "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
* cooling devices. It also gives the opportunity to link the cooling device
* with a device tree node, in order to bind it via the thermal DT code.
*
* Return: a valid struct thermal_cooling_device pointer on success,
* on failure, it returns a corresponding ERR_PTR().
*/
static struct thermal_cooling_device *
__cpufreq_cooling_register(struct device_node *np,
const struct cpumask *clip_cpus)
{
struct thermal_cooling_device *cool_dev;
struct cpufreq_cooling_device *cpufreq_dev;
char dev_name[THERMAL_NAME_LENGTH];
struct cpufreq_frequency_table *pos, *table;
unsigned int freq, i;
int ret;
table = cpufreq_frequency_get_table(cpumask_first(clip_cpus));
if (!table) {
pr_debug("%s: CPUFreq table not found\n", __func__);
return ERR_PTR(-EPROBE_DEFER);
}
cpufreq_dev = kzalloc(sizeof(*cpufreq_dev), GFP_KERNEL);
if (!cpufreq_dev)
return ERR_PTR(-ENOMEM);
ret = get_property(cpufreq_dev, 0, &cpufreq_dev->cpufreq_val, GET_FREQ);
if (ret) {
pr_err("%s: Failed to get frequency: %d", __func__, ret);
cool_dev = ERR_PTR(ret);
goto free_cdev;
}
/* Find max levels */
cpufreq_for_each_valid_entry(pos, table)
cpufreq_dev->max_level++;
cpufreq_dev->freq_table = kmalloc(sizeof(*cpufreq_dev->freq_table) *
cpufreq_dev->max_level, GFP_KERNEL);
if (!cpufreq_dev->freq_table) {
return ERR_PTR(-ENOMEM);
cool_dev = ERR_PTR(-ENOMEM);
goto free_cdev;
}
/* max_level is an index, not a counter */
cpufreq_dev->max_level--;
cpumask_copy(&cpufreq_dev->allowed_cpus, clip_cpus);
ret = get_idr(&cpufreq_idr, &cpufreq_dev->id);
if (ret) {
cool_dev = ERR_PTR(ret);
goto free_table;
}
snprintf(dev_name, sizeof(dev_name), "thermal-cpufreq-%d",
cpufreq_dev->id);
cool_dev = thermal_of_cooling_device_register(np, dev_name, cpufreq_dev,
&cpufreq_cooling_ops);
if (IS_ERR(cool_dev))
goto remove_idr;
/* Fill freq-table in descending order of frequencies */
for (i = 0, freq = -1; i <= cpufreq_dev->max_level; i++) {
freq = find_next_max(table, freq);
cpufreq_dev->freq_table[i] = freq;
/* Warn for duplicate entries */
if (!freq)
pr_warn("%s: table has duplicate entries\n", __func__);
else
pr_debug("%s: freq:%u KHz\n", __func__, freq);
}
cpufreq_dev->cool_dev = cool_dev;
mutex_lock(&cooling_cpufreq_lock);
/* Register the notifier for first cpufreq cooling device */
if (list_empty(&cpufreq_dev_list))
cpufreq_register_notifier(&thermal_cpufreq_notifier_block,
CPUFREQ_POLICY_NOTIFIER);
list_add(&cpufreq_dev->node, &cpufreq_dev_list);
mutex_unlock(&cooling_cpufreq_lock);
return cool_dev;
remove_idr:
release_idr(&cpufreq_idr, cpufreq_dev->id);
free_table:
kfree(cpufreq_dev->freq_table);
free_cdev:
kfree(cpufreq_dev);
return cool_dev;
}
/**
* cpufreq_cooling_register - function to create cpufreq cooling device.
* @clip_cpus: cpumask of cpus where the frequency constraints will happen.
*
* This interface function registers the cpufreq cooling device with the name
* "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
* cooling devices.
*
* Return: a valid struct thermal_cooling_device pointer on success,
* on failure, it returns a corresponding ERR_PTR().
*/
struct thermal_cooling_device *
cpufreq_cooling_register(const struct cpumask *clip_cpus)
{
return __cpufreq_cooling_register(NULL, clip_cpus);
}
EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
/**
* of_cpufreq_cooling_register - function to create cpufreq cooling device.
* @np: a valid struct device_node to the cooling device device tree node
* @clip_cpus: cpumask of cpus where the frequency constraints will happen.
*
* This interface function registers the cpufreq cooling device with the name
* "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
* cooling devices. Using this API, the cpufreq cooling device will be
* linked to the device tree node provided.
*
* Return: a valid struct thermal_cooling_device pointer on success,
* on failure, it returns a corresponding ERR_PTR().
*/
struct thermal_cooling_device *
of_cpufreq_cooling_register(struct device_node *np,
const struct cpumask *clip_cpus)
{
if (!np)
return ERR_PTR(-EINVAL);
return __cpufreq_cooling_register(np, clip_cpus);
}
EXPORT_SYMBOL_GPL(of_cpufreq_cooling_register);
/**
* cpufreq_cooling_unregister - function to remove cpufreq cooling device.
* @cdev: thermal cooling device pointer.
*
* This interface function unregisters the "thermal-cpufreq-%x" cooling device.
*/
void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
{
struct cpufreq_cooling_device *cpufreq_dev;
if (!cdev)
return;
cpufreq_dev = cdev->devdata;
mutex_lock(&cooling_cpufreq_lock);
list_del(&cpufreq_dev->node);
/* Unregister the notifier for the last cpufreq cooling device */
if (list_empty(&cpufreq_dev_list))
cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block,
CPUFREQ_POLICY_NOTIFIER);
mutex_unlock(&cooling_cpufreq_lock);
thermal_cooling_device_unregister(cpufreq_dev->cool_dev);
release_idr(&cpufreq_idr, cpufreq_dev->id);
kfree(cpufreq_dev->freq_table);
kfree(cpufreq_dev);
}
EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);
