1 files changed, 62 insertions, 67 deletions

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index a324801d6a66..551a271353d2 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -111,18 +111,16 @@ static void devfreq_set_freq_table(struct devfreq *devfreq)
 		return;
 	}
 
-	rcu_read_lock();
 	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;
-			rcu_read_unlock();
 			return;
 		}
+		dev_pm_opp_put(opp);
 		profile->freq_table[i] = freq;
 	}
-	rcu_read_unlock();
 }
 
 /**
@@ -130,7 +128,7 @@ static void devfreq_set_freq_table(struct devfreq *devfreq)
  * @devfreq:	the devfreq instance
  * @freq:	the update target frequency
  */
-static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
+int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 {
 	int lev, prev_lev, ret = 0;
 	unsigned long cur_time;
@@ -166,6 +164,7 @@ out:
 	devfreq->last_stat_updated = cur_time;
 	return ret;
 }
+EXPORT_SYMBOL(devfreq_update_status);
 
 /**
  * find_devfreq_governor() - find devfreq governor from name
@@ -474,11 +473,15 @@ static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 }
 
 /**
- * _remove_devfreq() - Remove devfreq from the list and release its resources.
- * @devfreq:	the devfreq struct
+ * 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 _remove_devfreq(struct devfreq *devfreq)
+static void devfreq_dev_release(struct device *dev)
 {
+	struct devfreq *devfreq = to_devfreq(dev);
+
 	mutex_lock(&devfreq_list_lock);
 	if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
 		mutex_unlock(&devfreq_list_lock);
@@ -500,19 +503,6 @@ static void _remove_devfreq(struct devfreq *devfreq)
 }
 
 /**
- * devfreq_dev_release() - Callback for struct device to release the device.
- * @dev:	the devfreq device
- *
- * This calls _remove_devfreq() if _remove_devfreq() is not called.
- */
-static void devfreq_dev_release(struct device *dev)
-{
-	struct devfreq *devfreq = to_devfreq(dev);
-
-	_remove_devfreq(devfreq);
-}
-
-/**
  * devfreq_add_device() - Add devfreq feature to the device
  * @dev:	the device to add devfreq feature.
  * @profile:	device-specific profile to run devfreq.
@@ -527,6 +517,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 {
 	struct devfreq *devfreq;
 	struct devfreq_governor *governor;
+	static atomic_t devfreq_no = ATOMIC_INIT(-1);
 	int err = 0;
 
 	if (!dev || !profile || !governor_name) {
@@ -538,15 +529,14 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	devfreq = find_device_devfreq(dev);
 	mutex_unlock(&devfreq_list_lock);
 	if (!IS_ERR(devfreq)) {
-		dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__);
+		dev_err(dev, "%s: Unable to create devfreq for the device.\n",
+			__func__);
 		err = -EINVAL;
 		goto err_out;
 	}
 
 	devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 	if (!devfreq) {
-		dev_err(dev, "%s: Unable to create devfreq for the device\n",
-			__func__);
 		err = -ENOMEM;
 		goto err_out;
 	}
@@ -569,18 +559,21 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		mutex_lock(&devfreq->lock);
 	}
 
-	dev_set_name(&devfreq->dev, "%s", dev_name(dev));
+	dev_set_name(&devfreq->dev, "devfreq%d",
+				atomic_inc_return(&devfreq_no));
 	err = device_register(&devfreq->dev);
 	if (err) {
 		mutex_unlock(&devfreq->lock);
 		goto err_out;
 	}
 
-	devfreq->trans_table =	devm_kzalloc(&devfreq->dev, sizeof(unsigned int) *
+	devfreq->trans_table =	devm_kzalloc(&devfreq->dev,
+						sizeof(unsigned int) *
 						devfreq->profile->max_state *
 						devfreq->profile->max_state,
 						GFP_KERNEL);
-	devfreq->time_in_state = devm_kzalloc(&devfreq->dev, sizeof(unsigned long) *
+	devfreq->time_in_state = devm_kzalloc(&devfreq->dev,
+						sizeof(unsigned long) *
 						devfreq->profile->max_state,
 						GFP_KERNEL);
 	devfreq->last_stat_updated = jiffies;
@@ -593,11 +586,16 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	list_add(&devfreq->node, &devfreq_list);
 
 	governor = find_devfreq_governor(devfreq->governor_name);
-	if (!IS_ERR(governor))
-		devfreq->governor = governor;
-	if (devfreq->governor)
-		err = devfreq->governor->event_handler(devfreq,
-					DEVFREQ_GOV_START, NULL);
+	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__);
@@ -934,6 +932,9 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 	if (df->governor == governor) {
 		ret = 0;
 		goto out;
+	} else if (df->governor->immutable || governor->immutable) {
+		ret = -EINVAL;
+		goto out;
 	}
 
 	if (df->governor) {
@@ -963,13 +964,33 @@ static ssize_t available_governors_show(struct device *d,
 					struct device_attribute *attr,
 					char *buf)
 {
-	struct devfreq_governor *tmp_governor;
+	struct devfreq *df = to_devfreq(d);
 	ssize_t count = 0;
 
 	mutex_lock(&devfreq_list_lock);
-	list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
-		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
-				   "%s ", tmp_governor->name);
+
+	/*
+	 * The devfreq with immutable governor (e.g., passive) shows
+	 * only own governor.
+	 */
+	if (df->governor->immutable) {
+		count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
+				   "%s ", df->governor_name);
+	/*
+	 * The devfreq device shows the registered governor except for
+	 * immutable governors such as passive governor .
+	 */
+	} else {
+		struct devfreq_governor *governor;
+
+		list_for_each_entry(governor, &devfreq_governor_list, node) {
+			if (governor->immutable)
+				continue;
+			count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+					   "%s ", governor->name);
+		}
+	}
+
 	mutex_unlock(&devfreq_list_lock);
 
 	/* Truncate the trailing space */
@@ -990,7 +1011,7 @@ static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
 
 	if (devfreq->profile->get_cur_freq &&
 		!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
-			return sprintf(buf, "%lu\n", freq);
+		return sprintf(buf, "%lu\n", freq);
 
 	return sprintf(buf, "%lu\n", devfreq->previous_freq);
 }
@@ -1107,17 +1128,16 @@ static ssize_t available_frequencies_show(struct device *d,
 	ssize_t count = 0;
 	unsigned long freq = 0;
 
-	rcu_read_lock();
 	do {
 		opp = dev_pm_opp_find_freq_ceil(dev, &freq);
 		if (IS_ERR(opp))
 			break;
 
+		dev_pm_opp_put(opp);
 		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
 				   "%lu ", freq);
 		freq++;
 	} while (1);
-	rcu_read_unlock();
 
 	/* Truncate the trailing space */
 	if (count)
@@ -1219,11 +1239,8 @@ subsys_initcall(devfreq_init);
  * @freq:	The frequency given to target function
  * @flags:	Flags handed from devfreq framework.
  *
- * Locking: This function must be called under rcu_read_lock(). opp is a rcu
- * protected pointer. The reason for the same is that the opp pointer which is
- * returned will remain valid for use with opp_get_{voltage, freq} only while
- * under the locked area. The pointer returned must be used prior to unlocking
- * with rcu_read_unlock() to maintain the integrity of the pointer.
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
  */
 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
 					   unsigned long *freq,
@@ -1260,18 +1277,7 @@ EXPORT_SYMBOL(devfreq_recommended_opp);
  */
 int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
 {
-	struct srcu_notifier_head *nh;
-	int ret = 0;
-
-	rcu_read_lock();
-	nh = dev_pm_opp_get_notifier(dev);
-	if (IS_ERR(nh))
-		ret = PTR_ERR(nh);
-	rcu_read_unlock();
-	if (!ret)
-		ret = srcu_notifier_chain_register(nh, &devfreq->nb);
-
-	return ret;
+	return dev_pm_opp_register_notifier(dev, &devfreq->nb);
 }
 EXPORT_SYMBOL(devfreq_register_opp_notifier);
 
@@ -1287,18 +1293,7 @@ EXPORT_SYMBOL(devfreq_register_opp_notifier);
  */
 int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
 {
-	struct srcu_notifier_head *nh;
-	int ret = 0;
-
-	rcu_read_lock();
-	nh = dev_pm_opp_get_notifier(dev);
-	if (IS_ERR(nh))
-		ret = PTR_ERR(nh);
-	rcu_read_unlock();
-	if (!ret)
-		ret = srcu_notifier_chain_unregister(nh, &devfreq->nb);
-
-	return ret;
+	return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
 }
 EXPORT_SYMBOL(devfreq_unregister_opp_notifier);