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PM / devfreq: Add new DEVFREQ_TRANSITION_NOTIFIER notifier
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This patch adds the new DEVFREQ_TRANSITION_NOTIFIER notifier to send
the notification when the frequency of device is changed.
This notifier has two state as following:
- DEVFREQ_PRECHANGE  : Notify it before chaning the frequency of device
- DEVFREQ_POSTCHANGE : Notify it after changed the frequency of device

And this patch adds the resourced-managed function to release the resource
automatically when error happen.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
[m.reichl and linux.amoon: Tested it on exynos4412-odroidu3 board]
Tested-by: Markus Reichl <m.reichl@fivetechno.de>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
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Chanwoo Choi authored and MyungJoo Ham committed May 3, 2016
1 parent 8f510ae commit 0fe3a66
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Showing 2 changed files with 220 additions and 2 deletions.
163 changes: 162 additions & 1 deletion drivers/devfreq/devfreq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -189,6 +189,29 @@ static struct devfreq_governor *find_devfreq_governor(const char *name)
return ERR_PTR(-ENODEV);
}

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;
}

/* Load monitoring helper functions for governors use */

/**
Expand All @@ -200,7 +223,8 @@ static struct devfreq_governor *find_devfreq_governor(const char *name)
*/
int update_devfreq(struct devfreq *devfreq)
{
unsigned long freq;
struct devfreq_freqs freqs;
unsigned long freq, cur_freq;
int err = 0;
u32 flags = 0;

Expand Down Expand Up @@ -234,10 +258,22 @@ int update_devfreq(struct devfreq *devfreq)
flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
}

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 = freq;
devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);

err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
if (err)
return err;

freqs.new = freq;
devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);

if (devfreq->profile->freq_table)
if (devfreq_update_status(devfreq, freq))
dev_err(&devfreq->dev,
Expand Down Expand Up @@ -542,6 +578,8 @@ struct devfreq *devfreq_add_device(struct device *dev,
goto err_out;
}

srcu_init_notifier_head(&devfreq->transition_notifier_list);

mutex_unlock(&devfreq->lock);

mutex_lock(&devfreq_list_lock);
Expand Down Expand Up @@ -1310,6 +1348,129 @@ void devm_devfreq_unregister_opp_notifier(struct device *dev,
}
EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);

/**
* devfreq_register_notifier() - Register a driver with devfreq
* @devfreq: The devfreq object.
* @nb: The notifier block to register.
* @list: DEVFREQ_TRANSITION_NOTIFIER.
*/
int devfreq_register_notifier(struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list)
{
int ret = 0;

if (!devfreq)
return -EINVAL;

switch (list) {
case DEVFREQ_TRANSITION_NOTIFIER:
ret = srcu_notifier_chain_register(
&devfreq->transition_notifier_list, nb);
break;
default:
ret = -EINVAL;
}

return ret;
}
EXPORT_SYMBOL(devfreq_register_notifier);

/*
* devfreq_unregister_notifier() - Unregister a driver with devfreq
* @devfreq: The devfreq object.
* @nb: The notifier block to be unregistered.
* @list: DEVFREQ_TRANSITION_NOTIFIER.
*/
int devfreq_unregister_notifier(struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list)
{
int ret = 0;

if (!devfreq)
return -EINVAL;

switch (list) {
case DEVFREQ_TRANSITION_NOTIFIER:
ret = srcu_notifier_chain_unregister(
&devfreq->transition_notifier_list, nb);
break;
default:
ret = -EINVAL;
}

return ret;
}
EXPORT_SYMBOL(devfreq_unregister_notifier);

struct devfreq_notifier_devres {
struct devfreq *devfreq;
struct notifier_block *nb;
unsigned int list;
};

static void devm_devfreq_notifier_release(struct device *dev, void *res)
{
struct devfreq_notifier_devres *this = res;

devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
}

/**
* devm_devfreq_register_notifier()
- Resource-managed devfreq_register_notifier()
* @dev: The devfreq user device. (parent of devfreq)
* @devfreq: The devfreq object.
* @nb: The notifier block to be unregistered.
* @list: DEVFREQ_TRANSITION_NOTIFIER.
*/
int devm_devfreq_register_notifier(struct device *dev,
struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list)
{
struct devfreq_notifier_devres *ptr;
int ret;

ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
GFP_KERNEL);
if (!ptr)
return -ENOMEM;

ret = devfreq_register_notifier(devfreq, nb, list);
if (ret) {
devres_free(ptr);
return ret;
}

ptr->devfreq = devfreq;
ptr->nb = nb;
ptr->list = list;
devres_add(dev, ptr);

return 0;
}
EXPORT_SYMBOL(devm_devfreq_register_notifier);

/**
* devm_devfreq_unregister_notifier()
- Resource-managed devfreq_unregister_notifier()
* @dev: The devfreq user device. (parent of devfreq)
* @devfreq: The devfreq object.
* @nb: The notifier block to be unregistered.
* @list: DEVFREQ_TRANSITION_NOTIFIER.
*/
void devm_devfreq_unregister_notifier(struct device *dev,
struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list)
{
WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
devm_devfreq_dev_match, devfreq));
}
EXPORT_SYMBOL(devm_devfreq_unregister_notifier);

MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
MODULE_DESCRIPTION("devfreq class support");
MODULE_LICENSE("GPL");
59 changes: 58 additions & 1 deletion include/linux/devfreq.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,13 @@

#define DEVFREQ_NAME_LEN 16

/* DEVFREQ notifier interface */
#define DEVFREQ_TRANSITION_NOTIFIER (0)

/* Transition notifiers of DEVFREQ_TRANSITION_NOTIFIER */
#define DEVFREQ_PRECHANGE (0)
#define DEVFREQ_POSTCHANGE (1)

struct devfreq;

/**
Expand Down Expand Up @@ -143,6 +150,7 @@ struct devfreq_governor {
* @trans_table: Statistics of devfreq transitions
* @time_in_state: Statistics of devfreq states
* @last_stat_updated: The last time stat updated
* @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
*
* This structure stores the devfreq information for a give device.
*
Expand Down Expand Up @@ -177,6 +185,13 @@ struct devfreq {
unsigned int *trans_table;
unsigned long *time_in_state;
unsigned long last_stat_updated;

struct srcu_notifier_head transition_notifier_list;
};

struct devfreq_freqs {
unsigned long old;
unsigned long new;
};

#if defined(CONFIG_PM_DEVFREQ)
Expand Down Expand Up @@ -207,7 +222,20 @@ extern int devm_devfreq_register_opp_notifier(struct device *dev,
struct devfreq *devfreq);
extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
struct devfreq *devfreq);

extern int devfreq_register_notifier(struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list);
extern int devfreq_unregister_notifier(struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list);
extern int devm_devfreq_register_notifier(struct device *dev,
struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list);
extern void devm_devfreq_unregister_notifier(struct device *dev,
struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list);
extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
int index);

Expand Down Expand Up @@ -310,6 +338,35 @@ static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
{
}

static inline int devfreq_register_notifier(struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list)
{
return 0;
}

static inline int devfreq_unregister_notifier(struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list)
{
return 0;
}

static inline int devm_devfreq_register_notifier(struct device *dev,
struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list)
{
return 0;
}

static inline void devm_devfreq_unregister_notifier(struct device *dev,
struct devfreq *devfreq,
struct notifier_block *nb,
unsigned int list)
{
}

static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
int index)
{
Expand Down

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