Commit 3aa173b8 authored by Nishanth Menon's avatar Nishanth Menon Committed by MyungJoo Ham

PM / devfreq: provide hooks for governors to be registered

Add devfreq_add_governor and devfreq_remove_governor which
can be invoked by governors to register with devfreq.

This sets up the stage to dynamically switch governors and
allow governors to be dynamically loaded as well.

Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Kevin Hilman <khilman@ti.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarNishanth Menon <nm@ti.com>
Acked-by: default avatarMyungJoo Ham <myungjoo.ham@samsung.com>
parent 2df5021f
...@@ -36,6 +36,8 @@ static struct class *devfreq_class; ...@@ -36,6 +36,8 @@ static struct class *devfreq_class;
*/ */
static struct workqueue_struct *devfreq_wq; 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 */ /* The list of all device-devfreq */
static LIST_HEAD(devfreq_list); static LIST_HEAD(devfreq_list);
static DEFINE_MUTEX(devfreq_list_lock); static DEFINE_MUTEX(devfreq_list_lock);
...@@ -111,6 +113,32 @@ static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) ...@@ -111,6 +113,32 @@ static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
return 0; return 0;
} }
/**
* 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;
if (unlikely(IS_ERR_OR_NULL(name))) {
pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
return ERR_PTR(-EINVAL);
}
WARN(!mutex_is_locked(&devfreq_list_lock),
"devfreq_list_lock must be locked.");
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);
}
/* Load monitoring helper functions for governors use */ /* Load monitoring helper functions for governors use */
/** /**
...@@ -515,6 +543,69 @@ int devfreq_resume_device(struct devfreq *devfreq) ...@@ -515,6 +543,69 @@ int devfreq_resume_device(struct devfreq *devfreq)
} }
EXPORT_SYMBOL(devfreq_resume_device); EXPORT_SYMBOL(devfreq_resume_device);
/**
* devfreq_add_governor() - Add devfreq governor
* @governor: the devfreq governor to be added
*/
int devfreq_add_governor(struct devfreq_governor *governor)
{
struct devfreq_governor *g;
int err = 0;
if (!governor) {
pr_err("%s: Invalid parameters.\n", __func__);
return -EINVAL;
}
mutex_lock(&devfreq_list_lock);
g = find_devfreq_governor(governor->name);
if (!IS_ERR(g)) {
pr_err("%s: governor %s already registered\n", __func__,
g->name);
err = -EINVAL;
goto err_out;
}
list_add(&governor->node, &devfreq_governor_list);
err_out:
mutex_unlock(&devfreq_list_lock);
return err;
}
EXPORT_SYMBOL(devfreq_add_governor);
/**
* devfreq_remove_device() - Remove devfreq feature from a device.
* @governor: the devfreq governor to be removed
*/
int devfreq_remove_governor(struct devfreq_governor *governor)
{
struct devfreq_governor *g;
int err = 0;
if (!governor) {
pr_err("%s: Invalid parameters.\n", __func__);
return -EINVAL;
}
mutex_lock(&devfreq_list_lock);
g = find_devfreq_governor(governor->name);
if (IS_ERR(g)) {
pr_err("%s: governor %s not registered\n", __func__,
g->name);
err = -EINVAL;
goto err_out;
}
list_del(&governor->node);
err_out:
mutex_unlock(&devfreq_list_lock);
return err;
}
EXPORT_SYMBOL(devfreq_remove_governor);
static ssize_t show_governor(struct device *dev, static ssize_t show_governor(struct device *dev,
struct device_attribute *attr, char *buf) struct device_attribute *attr, char *buf)
{ {
......
...@@ -34,4 +34,8 @@ extern void devfreq_monitor_suspend(struct devfreq *devfreq); ...@@ -34,4 +34,8 @@ extern void devfreq_monitor_suspend(struct devfreq *devfreq);
extern void devfreq_monitor_resume(struct devfreq *devfreq); extern void devfreq_monitor_resume(struct devfreq *devfreq);
extern void devfreq_interval_update(struct devfreq *devfreq, extern void devfreq_interval_update(struct devfreq *devfreq,
unsigned int *delay); unsigned int *delay);
extern int devfreq_add_governor(struct devfreq_governor *governor);
extern int devfreq_remove_governor(struct devfreq_governor *governor);
#endif /* _GOVERNOR_H */ #endif /* _GOVERNOR_H */
...@@ -92,6 +92,7 @@ struct devfreq_dev_profile { ...@@ -92,6 +92,7 @@ struct devfreq_dev_profile {
/** /**
* struct devfreq_governor - Devfreq policy governor * struct devfreq_governor - Devfreq policy governor
* @node: list node - contains registered devfreq governors
* @name: Governor's name * @name: Governor's name
* @get_target_freq: Returns desired operating frequency for the device. * @get_target_freq: Returns desired operating frequency for the device.
* Basically, get_target_freq will run * Basically, get_target_freq will run
...@@ -107,6 +108,8 @@ struct devfreq_dev_profile { ...@@ -107,6 +108,8 @@ struct devfreq_dev_profile {
* Note that the callbacks are called with devfreq->lock locked by devfreq. * Note that the callbacks are called with devfreq->lock locked by devfreq.
*/ */
struct devfreq_governor { struct devfreq_governor {
struct list_head node;
const char name[DEVFREQ_NAME_LEN]; const char name[DEVFREQ_NAME_LEN];
int (*get_target_freq)(struct devfreq *this, unsigned long *freq); int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
int (*event_handler)(struct devfreq *devfreq, int (*event_handler)(struct devfreq *devfreq,
......
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