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Date: Mon, 29 Oct 2012 15:01:43 -0500
From: Nishanth Menon <nm@...com>
To: linux-pm <linux-pm@...r.kernel.org>
CC: Nishanth Menon <nm@...com>,
Rajagopal Venkat <rajagopal.venkat@...aro.org>,
MyungJoo Ham <myungjoo.ham@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
"Rafael J. Wysocki" <rjw@...k.pl>, Kevin Hilman <khilman@...com>,
<linux-kernel@...r.kernel.org>
Subject: [linux-next PATCH 2/7] 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@...aro.org>
Cc: MyungJoo Ham <myungjoo.ham@...sung.com>
Cc: Kyungmin Park <kyungmin.park@...sung.com>
Cc: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: Kevin Hilman <khilman@...com>
Cc: linux-pm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Nishanth Menon <nm@...com>
---
drivers/devfreq/devfreq.c | 91 ++++++++++++++++++++++++++++++++++++++++++++
drivers/devfreq/governor.h | 4 ++
include/linux/devfreq.h | 3 ++
3 files changed, 98 insertions(+)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 6d3070d..9c079d2 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -36,6 +36,8 @@ static struct class *devfreq_class;
*/
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);
@@ -66,6 +68,32 @@ static struct devfreq *find_device_devfreq(struct device *dev)
return ERR_PTR(-ENODEV);
}
+/**
+ * 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 */
/**
@@ -456,6 +484,69 @@ int devfreq_resume_device(struct devfreq *devfreq)
}
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,
struct device_attribute *attr, char *buf)
{
diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
index 26432ac..fad7d63 100644
--- a/drivers/devfreq/governor.h
+++ b/drivers/devfreq/governor.h
@@ -34,4 +34,8 @@ extern void devfreq_monitor_suspend(struct devfreq *devfreq);
extern void devfreq_monitor_resume(struct devfreq *devfreq);
extern void devfreq_interval_update(struct devfreq *devfreq,
unsigned int *delay);
+
+extern int devfreq_add_governor(struct devfreq_governor *governor);
+extern int devfreq_remove_governor(struct devfreq_governor *governor);
+
#endif /* _GOVERNOR_H */
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 1461fb2..a28d935 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -87,6 +87,7 @@ struct devfreq_dev_profile {
/**
* struct devfreq_governor - Devfreq policy governor
+ * @node: list node - contains registered devfreq governors
* @name: Governor's name
* @get_target_freq: Returns desired operating frequency for the device.
* Basically, get_target_freq will run
@@ -102,6 +103,8 @@ struct devfreq_dev_profile {
* Note that the callbacks are called with devfreq->lock locked by devfreq.
*/
struct devfreq_governor {
+ struct list_head node;
+
const char name[DEVFREQ_NAME_LEN];
int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
int (*event_handler)(struct devfreq *devfreq,
--
1.7.9.5
--
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