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devfreq.c
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devfreq.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
* for Non-CPU Devices.
*
* Copyright (C) 2011 Samsung Electronics
* MyungJoo Ham <myungjoo.ham@samsung.com>
*/
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/sched.h>
#include <linux/debugfs.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/pm_opp.h>
#include <linux/devfreq.h>
#include <linux/workqueue.h>
#include <linux/platform_device.h>
#include <linux/list.h>
#include <linux/printk.h>
#include <linux/hrtimer.h>
#include <linux/of.h>
#include <linux/pm_qos.h>
#include "governor.h"
#define CREATE_TRACE_POINTS
#include <trace/events/devfreq.h>
#define HZ_PER_KHZ 1000
static struct class *devfreq_class;
static struct dentry *devfreq_debugfs;
/*
* devfreq core provides delayed work based load monitoring helper
* functions. Governors can use these or can implement their own
* monitoring mechanism.
*/
static struct workqueue_struct *devfreq_wq;
/* The list of all device-devfreq governors */
static LIST_HEAD(devfreq_governor_list);
/* The list of all device-devfreq */
static LIST_HEAD(devfreq_list);
static DEFINE_MUTEX(devfreq_list_lock);
/**
* find_device_devfreq() - find devfreq struct using device pointer
* @dev: device pointer used to lookup device devfreq.
*
* Search the list of device devfreqs and return the matched device's
* devfreq info. devfreq_list_lock should be held by the caller.
*/
static struct devfreq *find_device_devfreq(struct device *dev)
{
struct devfreq *tmp_devfreq;
lockdep_assert_held(&devfreq_list_lock);
if (IS_ERR_OR_NULL(dev)) {
pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
return ERR_PTR(-EINVAL);
}
list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
if (tmp_devfreq->dev.parent == dev)
return tmp_devfreq;
}
return ERR_PTR(-ENODEV);
}
static unsigned long find_available_min_freq(struct devfreq *devfreq)
{
struct dev_pm_opp *opp;
unsigned long min_freq = 0;
opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
if (IS_ERR(opp))
min_freq = 0;
else
dev_pm_opp_put(opp);
return min_freq;
}
static unsigned long find_available_max_freq(struct devfreq *devfreq)
{
struct dev_pm_opp *opp;
unsigned long max_freq = ULONG_MAX;
opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
if (IS_ERR(opp))
max_freq = 0;
else
dev_pm_opp_put(opp);
return max_freq;
}
/**
* get_freq_range() - Get the current freq range
* @devfreq: the devfreq instance
* @min_freq: the min frequency
* @max_freq: the max frequency
*
* This takes into consideration all constraints.
*/
static void get_freq_range(struct devfreq *devfreq,
unsigned long *min_freq,
unsigned long *max_freq)
{
unsigned long *freq_table = devfreq->profile->freq_table;
s32 qos_min_freq, qos_max_freq;
lockdep_assert_held(&devfreq->lock);
/*
* Initialize minimum/maximum frequency from freq table.
* The devfreq drivers can initialize this in either ascending or
* descending order and devfreq core supports both.
*/
if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
*min_freq = freq_table[0];
*max_freq = freq_table[devfreq->profile->max_state - 1];
} else {
*min_freq = freq_table[devfreq->profile->max_state - 1];
*max_freq = freq_table[0];
}
/* Apply constraints from PM QoS */
qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
DEV_PM_QOS_MIN_FREQUENCY);
qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
DEV_PM_QOS_MAX_FREQUENCY);
*min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
*max_freq = min(*max_freq,
(unsigned long)HZ_PER_KHZ * qos_max_freq);
/* Apply constraints from OPP interface */
*min_freq = max(*min_freq, devfreq->scaling_min_freq);
*max_freq = min(*max_freq, devfreq->scaling_max_freq);
if (*min_freq > *max_freq)
*min_freq = *max_freq;
}
/**
* devfreq_get_freq_level() - Lookup freq_table for the frequency
* @devfreq: the devfreq instance
* @freq: the target frequency
*/
static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
{
int lev;
for (lev = 0; lev < devfreq->profile->max_state; lev++)
if (freq == devfreq->profile->freq_table[lev])
return lev;
return -EINVAL;
}
static int set_freq_table(struct devfreq *devfreq)
{
struct devfreq_dev_profile *profile = devfreq->profile;
struct dev_pm_opp *opp;
unsigned long freq;
int i, count;
/* Initialize the freq_table from OPP table */
count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
if (count <= 0)
return -EINVAL;
profile->max_state = count;
profile->freq_table = devm_kcalloc(devfreq->dev.parent,
profile->max_state,
sizeof(*profile->freq_table),
GFP_KERNEL);
if (!profile->freq_table) {
profile->max_state = 0;
return -ENOMEM;
}
for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
if (IS_ERR(opp)) {
devm_kfree(devfreq->dev.parent, profile->freq_table);
profile->max_state = 0;
return PTR_ERR(opp);
}
dev_pm_opp_put(opp);
profile->freq_table[i] = freq;
}
return 0;
}
/**
* devfreq_update_status() - Update statistics of devfreq behavior
* @devfreq: the devfreq instance
* @freq: the update target frequency
*/
int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
{
int lev, prev_lev, ret = 0;
u64 cur_time;
lockdep_assert_held(&devfreq->lock);
cur_time = get_jiffies_64();
/* Immediately exit if previous_freq is not initialized yet. */
if (!devfreq->previous_freq)
goto out;
prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
if (prev_lev < 0) {
ret = prev_lev;
goto out;
}
devfreq->stats.time_in_state[prev_lev] +=
cur_time - devfreq->stats.last_update;
lev = devfreq_get_freq_level(devfreq, freq);
if (lev < 0) {
ret = lev;
goto out;
}
if (lev != prev_lev) {
devfreq->stats.trans_table[
(prev_lev * devfreq->profile->max_state) + lev]++;
devfreq->stats.total_trans++;
}
out:
devfreq->stats.last_update = cur_time;
return ret;
}
EXPORT_SYMBOL(devfreq_update_status);
/**
* find_devfreq_governor() - find devfreq governor from name
* @name: name of the governor
*
* Search the list of devfreq governors and return the matched
* governor's pointer. devfreq_list_lock should be held by the caller.
*/
static struct devfreq_governor *find_devfreq_governor(const char *name)
{
struct devfreq_governor *tmp_governor;
lockdep_assert_held(&devfreq_list_lock);
if (IS_ERR_OR_NULL(name)) {
pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
return ERR_PTR(-EINVAL);
}
list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
return tmp_governor;
}
return ERR_PTR(-ENODEV);
}
/**
* try_then_request_governor() - Try to find the governor and request the
* module if is not found.
* @name: name of the governor
*
* Search the list of devfreq governors and request the module and try again
* if is not found. This can happen when both drivers (the governor driver
* and the driver that call devfreq_add_device) are built as modules.
* devfreq_list_lock should be held by the caller. Returns the matched
* governor's pointer or an error pointer.
*/
static struct devfreq_governor *try_then_request_governor(const char *name)
{
struct devfreq_governor *governor;
int err = 0;
lockdep_assert_held(&devfreq_list_lock);
if (IS_ERR_OR_NULL(name)) {
pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
return ERR_PTR(-EINVAL);
}
governor = find_devfreq_governor(name);
if (IS_ERR(governor)) {
mutex_unlock(&devfreq_list_lock);
if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
DEVFREQ_NAME_LEN))
err = request_module("governor_%s", "simpleondemand");
else
err = request_module("governor_%s", name);
/* Restore previous state before return */
mutex_lock(&devfreq_list_lock);
if (err)
return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
governor = find_devfreq_governor(name);
}
return governor;
}
static int devfreq_notify_transition(struct devfreq *devfreq,
struct devfreq_freqs *freqs, unsigned int state)
{
if (!devfreq)
return -EINVAL;
switch (state) {
case DEVFREQ_PRECHANGE:
srcu_notifier_call_chain(&devfreq->transition_notifier_list,
DEVFREQ_PRECHANGE, freqs);
break;
case DEVFREQ_POSTCHANGE:
srcu_notifier_call_chain(&devfreq->transition_notifier_list,
DEVFREQ_POSTCHANGE, freqs);
break;
default:
return -EINVAL;
}
return 0;
}
static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
u32 flags)
{
struct devfreq_freqs freqs;
unsigned long cur_freq;
int err = 0;
if (devfreq->profile->get_cur_freq)
devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
else
cur_freq = devfreq->previous_freq;
freqs.old = cur_freq;
freqs.new = new_freq;
devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
if (err) {
freqs.new = cur_freq;
devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
return err;
}
freqs.new = new_freq;
devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
if (devfreq_update_status(devfreq, new_freq))
dev_err(&devfreq->dev,
"Couldn't update frequency transition information.\n");
devfreq->previous_freq = new_freq;
if (devfreq->suspend_freq)
devfreq->resume_freq = cur_freq;
return err;
}
/* Load monitoring helper functions for governors use */
/**
* update_devfreq() - Reevaluate the device and configure frequency.
* @devfreq: the devfreq instance.
*
* Note: Lock devfreq->lock before calling update_devfreq
* This function is exported for governors.
*/
int update_devfreq(struct devfreq *devfreq)
{
unsigned long freq, min_freq, max_freq;
int err = 0;
u32 flags = 0;
lockdep_assert_held(&devfreq->lock);
if (!devfreq->governor)
return -EINVAL;
/* Reevaluate the proper frequency */
err = devfreq->governor->get_target_freq(devfreq, &freq);
if (err)
return err;
get_freq_range(devfreq, &min_freq, &max_freq);
if (freq < min_freq) {
freq = min_freq;
flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
}
if (freq > max_freq) {
freq = max_freq;
flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
}
return devfreq_set_target(devfreq, freq, flags);
}
EXPORT_SYMBOL(update_devfreq);
/**
* devfreq_monitor() - Periodically poll devfreq objects.
* @work: the work struct used to run devfreq_monitor periodically.
*
*/
static void devfreq_monitor(struct work_struct *work)
{
int err;
struct devfreq *devfreq = container_of(work,
struct devfreq, work.work);
mutex_lock(&devfreq->lock);
err = update_devfreq(devfreq);
if (err)
dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
queue_delayed_work(devfreq_wq, &devfreq->work,
msecs_to_jiffies(devfreq->profile->polling_ms));
mutex_unlock(&devfreq->lock);
trace_devfreq_monitor(devfreq);
}
/**
* devfreq_monitor_start() - Start load monitoring of devfreq instance
* @devfreq: the devfreq instance.
*
* Helper function for starting devfreq device load monitoring. By
* default delayed work based monitoring is supported. Function
* to be called from governor in response to DEVFREQ_GOV_START
* event when device is added to devfreq framework.
*/
void devfreq_monitor_start(struct devfreq *devfreq)
{
if (devfreq->governor->interrupt_driven)
return;
INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
if (devfreq->profile->polling_ms)
queue_delayed_work(devfreq_wq, &devfreq->work,
msecs_to_jiffies(devfreq->profile->polling_ms));
}
EXPORT_SYMBOL(devfreq_monitor_start);
/**
* devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
* @devfreq: the devfreq instance.
*
* Helper function to stop devfreq device load monitoring. Function
* to be called from governor in response to DEVFREQ_GOV_STOP
* event when device is removed from devfreq framework.
*/
void devfreq_monitor_stop(struct devfreq *devfreq)
{
if (devfreq->governor->interrupt_driven)
return;
cancel_delayed_work_sync(&devfreq->work);
}
EXPORT_SYMBOL(devfreq_monitor_stop);
/**
* devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
* @devfreq: the devfreq instance.
*
* Helper function to suspend devfreq device load monitoring. Function
* to be called from governor in response to DEVFREQ_GOV_SUSPEND
* event or when polling interval is set to zero.
*
* Note: Though this function is same as devfreq_monitor_stop(),
* intentionally kept separate to provide hooks for collecting
* transition statistics.
*/
void devfreq_monitor_suspend(struct devfreq *devfreq)
{
mutex_lock(&devfreq->lock);
if (devfreq->stop_polling) {
mutex_unlock(&devfreq->lock);
return;
}
devfreq_update_status(devfreq, devfreq->previous_freq);
devfreq->stop_polling = true;
mutex_unlock(&devfreq->lock);
if (devfreq->governor->interrupt_driven)
return;
cancel_delayed_work_sync(&devfreq->work);
}
EXPORT_SYMBOL(devfreq_monitor_suspend);
/**
* devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
* @devfreq: the devfreq instance.
*
* Helper function to resume devfreq device load monitoring. Function
* to be called from governor in response to DEVFREQ_GOV_RESUME
* event or when polling interval is set to non-zero.
*/
void devfreq_monitor_resume(struct devfreq *devfreq)
{
unsigned long freq;
mutex_lock(&devfreq->lock);
if (!devfreq->stop_polling)
goto out;
if (devfreq->governor->interrupt_driven)
goto out_update;
if (!delayed_work_pending(&devfreq->work) &&
devfreq->profile->polling_ms)
queue_delayed_work(devfreq_wq, &devfreq->work,
msecs_to_jiffies(devfreq->profile->polling_ms));
out_update:
devfreq->stats.last_update = get_jiffies_64();
devfreq->stop_polling = false;
if (devfreq->profile->get_cur_freq &&
!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
devfreq->previous_freq = freq;
out:
mutex_unlock(&devfreq->lock);
}
EXPORT_SYMBOL(devfreq_monitor_resume);
/**
* devfreq_update_interval() - Update device devfreq monitoring interval
* @devfreq: the devfreq instance.
* @delay: new polling interval to be set.
*
* Helper function to set new load monitoring polling interval. Function
* to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
*/
void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
{
unsigned int cur_delay = devfreq->profile->polling_ms;
unsigned int new_delay = *delay;
mutex_lock(&devfreq->lock);
devfreq->profile->polling_ms = new_delay;
if (devfreq->stop_polling)
goto out;
if (devfreq->governor->interrupt_driven)
goto out;
/* if new delay is zero, stop polling */
if (!new_delay) {
mutex_unlock(&devfreq->lock);
cancel_delayed_work_sync(&devfreq->work);
return;
}
/* if current delay is zero, start polling with new delay */
if (!cur_delay) {
queue_delayed_work(devfreq_wq, &devfreq->work,
msecs_to_jiffies(devfreq->profile->polling_ms));
goto out;
}
/* if current delay is greater than new delay, restart polling */
if (cur_delay > new_delay) {
mutex_unlock(&devfreq->lock);
cancel_delayed_work_sync(&devfreq->work);
mutex_lock(&devfreq->lock);
if (!devfreq->stop_polling)
queue_delayed_work(devfreq_wq, &devfreq->work,
msecs_to_jiffies(devfreq->profile->polling_ms));
}
out:
mutex_unlock(&devfreq->lock);
}
EXPORT_SYMBOL(devfreq_update_interval);
/**
* devfreq_notifier_call() - Notify that the device frequency requirements
* has been changed out of devfreq framework.
* @nb: the notifier_block (supposed to be devfreq->nb)
* @type: not used
* @devp: not used
*
* Called by a notifier that uses devfreq->nb.
*/
static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
void *devp)
{
struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
int err = -EINVAL;
mutex_lock(&devfreq->lock);
devfreq->scaling_min_freq = find_available_min_freq(devfreq);
if (!devfreq->scaling_min_freq)
goto out;
devfreq->scaling_max_freq = find_available_max_freq(devfreq);
if (!devfreq->scaling_max_freq) {
devfreq->scaling_max_freq = ULONG_MAX;
goto out;
}
err = update_devfreq(devfreq);
out:
mutex_unlock(&devfreq->lock);
if (err)
dev_err(devfreq->dev.parent,
"failed to update frequency from OPP notifier (%d)\n",
err);
return NOTIFY_OK;
}
/**
* qos_notifier_call() - Common handler for QoS constraints.
* @devfreq: the devfreq instance.
*/
static int qos_notifier_call(struct devfreq *devfreq)
{
int err;
mutex_lock(&devfreq->lock);
err = update_devfreq(devfreq);
mutex_unlock(&devfreq->lock);
if (err)
dev_err(devfreq->dev.parent,
"failed to update frequency from PM QoS (%d)\n",
err);
return NOTIFY_OK;
}
/**
* qos_min_notifier_call() - Callback for QoS min_freq changes.
* @nb: Should be devfreq->nb_min
*/
static int qos_min_notifier_call(struct notifier_block *nb,
unsigned long val, void *ptr)
{
return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
}
/**
* qos_max_notifier_call() - Callback for QoS max_freq changes.
* @nb: Should be devfreq->nb_max
*/
static int qos_max_notifier_call(struct notifier_block *nb,
unsigned long val, void *ptr)
{
return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
}
/**
* devfreq_dev_release() - Callback for struct device to release the device.
* @dev: the devfreq device
*
* Remove devfreq from the list and release its resources.
*/
static void devfreq_dev_release(struct device *dev)
{
struct devfreq *devfreq = to_devfreq(dev);
int err;
mutex_lock(&devfreq_list_lock);
list_del(&devfreq->node);
mutex_unlock(&devfreq_list_lock);
err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
DEV_PM_QOS_MAX_FREQUENCY);
if (err && err != -ENOENT)
dev_warn(dev->parent,
"Failed to remove max_freq notifier: %d\n", err);
err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
DEV_PM_QOS_MIN_FREQUENCY);
if (err && err != -ENOENT)
dev_warn(dev->parent,
"Failed to remove min_freq notifier: %d\n", err);
if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
if (err < 0)
dev_warn(dev->parent,
"Failed to remove max_freq request: %d\n", err);
}
if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
if (err < 0)
dev_warn(dev->parent,
"Failed to remove min_freq request: %d\n", err);
}
if (devfreq->profile->exit)
devfreq->profile->exit(devfreq->dev.parent);
mutex_destroy(&devfreq->lock);
kfree(devfreq);
}
/**
* devfreq_add_device() - Add devfreq feature to the device
* @dev: the device to add devfreq feature.
* @profile: device-specific profile to run devfreq.
* @governor_name: name of the policy to choose frequency.
* @data: private data for the governor. The devfreq framework does not
* touch this value.
*/
struct devfreq *devfreq_add_device(struct device *dev,
struct devfreq_dev_profile *profile,
const char *governor_name,
void *data)
{
struct devfreq *devfreq;
struct devfreq_governor *governor;
int err = 0;
if (!dev || !profile || !governor_name) {
dev_err(dev, "%s: Invalid parameters.\n", __func__);
return ERR_PTR(-EINVAL);
}
mutex_lock(&devfreq_list_lock);
devfreq = find_device_devfreq(dev);
mutex_unlock(&devfreq_list_lock);
if (!IS_ERR(devfreq)) {
dev_err(dev, "%s: devfreq device already exists!\n",
__func__);
err = -EINVAL;
goto err_out;
}
devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
if (!devfreq) {
err = -ENOMEM;
goto err_out;
}
mutex_init(&devfreq->lock);
mutex_lock(&devfreq->lock);
devfreq->dev.parent = dev;
devfreq->dev.class = devfreq_class;
devfreq->dev.release = devfreq_dev_release;
INIT_LIST_HEAD(&devfreq->node);
devfreq->profile = profile;
strscpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
devfreq->previous_freq = profile->initial_freq;
devfreq->last_status.current_frequency = profile->initial_freq;
devfreq->data = data;
devfreq->nb.notifier_call = devfreq_notifier_call;
if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
mutex_unlock(&devfreq->lock);
err = set_freq_table(devfreq);
if (err < 0)
goto err_dev;
mutex_lock(&devfreq->lock);
}
devfreq->scaling_min_freq = find_available_min_freq(devfreq);
if (!devfreq->scaling_min_freq) {
mutex_unlock(&devfreq->lock);
err = -EINVAL;
goto err_dev;
}
devfreq->scaling_max_freq = find_available_max_freq(devfreq);
if (!devfreq->scaling_max_freq) {
mutex_unlock(&devfreq->lock);
err = -EINVAL;
goto err_dev;
}
devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
atomic_set(&devfreq->suspend_count, 0);
dev_set_name(&devfreq->dev, "%s", dev_name(dev));
err = device_register(&devfreq->dev);
if (err) {
mutex_unlock(&devfreq->lock);
put_device(&devfreq->dev);
goto err_out;
}
devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
array3_size(sizeof(unsigned int),
devfreq->profile->max_state,
devfreq->profile->max_state),
GFP_KERNEL);
if (!devfreq->stats.trans_table) {
mutex_unlock(&devfreq->lock);
err = -ENOMEM;
goto err_devfreq;
}
devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
devfreq->profile->max_state,
sizeof(*devfreq->stats.time_in_state),
GFP_KERNEL);
if (!devfreq->stats.time_in_state) {
mutex_unlock(&devfreq->lock);
err = -ENOMEM;
goto err_devfreq;
}
devfreq->stats.total_trans = 0;
devfreq->stats.last_update = get_jiffies_64();
srcu_init_notifier_head(&devfreq->transition_notifier_list);
mutex_unlock(&devfreq->lock);
err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
DEV_PM_QOS_MIN_FREQUENCY, 0);
if (err < 0)
goto err_devfreq;
err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
DEV_PM_QOS_MAX_FREQUENCY,
PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
if (err < 0)
goto err_devfreq;
devfreq->nb_min.notifier_call = qos_min_notifier_call;
err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_min,
DEV_PM_QOS_MIN_FREQUENCY);
if (err)
goto err_devfreq;
devfreq->nb_max.notifier_call = qos_max_notifier_call;
err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_max,
DEV_PM_QOS_MAX_FREQUENCY);
if (err)
goto err_devfreq;
mutex_lock(&devfreq_list_lock);
governor = try_then_request_governor(devfreq->governor_name);
if (IS_ERR(governor)) {
dev_err(dev, "%s: Unable to find governor for the device\n",
__func__);
err = PTR_ERR(governor);
goto err_init;
}
devfreq->governor = governor;
err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
NULL);
if (err) {
dev_err(dev, "%s: Unable to start governor for the device\n",
__func__);
goto err_init;
}
list_add(&devfreq->node, &devfreq_list);
mutex_unlock(&devfreq_list_lock);
return devfreq;
err_init:
mutex_unlock(&devfreq_list_lock);
err_devfreq:
devfreq_remove_device(devfreq);
devfreq = NULL;
err_dev:
kfree(devfreq);
err_out:
return ERR_PTR(err);
}
EXPORT_SYMBOL(devfreq_add_device);
/**
* devfreq_remove_device() - Remove devfreq feature from a device.
* @devfreq: the devfreq instance to be removed
*
* The opposite of devfreq_add_device().
*/
int devfreq_remove_device(struct devfreq *devfreq)
{
if (!devfreq)
return -EINVAL;
if (devfreq->governor)
devfreq->governor->event_handler(devfreq,
DEVFREQ_GOV_STOP, NULL);
device_unregister(&devfreq->dev);
return 0;
}
EXPORT_SYMBOL(devfreq_remove_device);
static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
{
struct devfreq **r = res;
if (WARN_ON(!r || !*r))
return 0;
return *r == data;
}
static void devm_devfreq_dev_release(struct device *dev, void *res)
{
devfreq_remove_device(*(struct devfreq **)res);
}
/**
* devm_devfreq_add_device() - Resource-managed devfreq_add_device()
* @dev: the device to add devfreq feature.
* @profile: device-specific profile to run devfreq.
* @governor_name: name of the policy to choose frequency.
* @data: private data for the governor. The devfreq framework does not
* touch this value.
*
* This function manages automatically the memory of devfreq device using device
* resource management and simplify the free operation for memory of devfreq
* device.
*/
struct devfreq *devm_devfreq_add_device(struct device *dev,
struct devfreq_dev_profile *profile,
const char *governor_name,
void *data)
{
struct devfreq **ptr, *devfreq;
ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
devfreq = devfreq_add_device(dev, profile, governor_name, data);
if (IS_ERR(devfreq)) {
devres_free(ptr);
return devfreq;
}
*ptr = devfreq;
devres_add(dev, ptr);
return devfreq;
}
EXPORT_SYMBOL(devm_devfreq_add_device);
#ifdef CONFIG_OF
/*
* devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
* @dev - instance to the given device
* @index - index into list of devfreq
*
* return the instance of devfreq device
*/
struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
{
struct device_node *node;
struct devfreq *devfreq;
if (!dev)
return ERR_PTR(-EINVAL);
if (!dev->of_node)
return ERR_PTR(-EINVAL);
node = of_parse_phandle(dev->of_node, "devfreq", index);
if (!node)
return ERR_PTR(-ENODEV);
mutex_lock(&devfreq_list_lock);
list_for_each_entry(devfreq, &devfreq_list, node) {
if (devfreq->dev.parent
&& devfreq->dev.parent->of_node == node) {
mutex_unlock(&devfreq_list_lock);
of_node_put(node);
return devfreq;
}
}
mutex_unlock(&devfreq_list_lock);
of_node_put(node);
return ERR_PTR(-EPROBE_DEFER);