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Subject[PATCH v6 04/21] PM / devfreq: Add new DEVFREQ_TRANSITION_NOTIFIER notifier
Date
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>
---
drivers/devfreq/devfreq.c | 163 +++++++++++++++++++++++++++++++++++++++++++++-
include/linux/devfreq.h | 58 ++++++++++++++++-
2 files changed, 219 insertions(+), 2 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 20a9422c2552..1d6c803804d5 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -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 */

/**
@@ -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;

@@ -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,
@@ -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);
@@ -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");
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index aa0b8424ebc3..152ea342529c 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -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;

/**
@@ -177,6 +184,13 @@ 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)
@@ -207,7 +221,20 @@ 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);

@@ -310,6 +337,35 @@ 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)
{
--
1.9.1
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