[PATCHv2 0/5] devfreq: Support resource management functions and code clean

[PATCHv2 0/5] devfreq: Support resource management functions and code clean

[Chanwoo Choi]

This patchset fix devfreq_remove_device() to remove duplicate function call
of _remove_devfreq() and add following functions for the resource management
of devfreq device and simpify the control of resource on exynos4_bus/exynos5_bus
driver.
- devm_devfreq_add_device
- devm_devfreq_remove_device
- devm_devfreq_register_opp_notifier
- devm_devfreq_unregister_opp_notifier

Changes from v1:
- Remove empty function (exynos5_init_exit) and propogate the return value
  without additonal local variable if failed to call devm_devfreqw_add_device
  in exynos5_busfreq.c.
- Fix return value from -ENOMEM to -ENOSYS in devm_devfreq_add_device() inline
  function.
- Fix minor coding style of devm_devfreq_dev_match()

Chanwoo Choi (5):
  devfreq: Fix devfreq_remove_device() to improve the sequence of resource free
  devfreq: Add resource-managed function for devfreq device
  devfreq: Add devm_devfreq_{register,unregister}_opp_notfier function
  devfreq: exynos4: Use devm_devfreq_* function using device resource management
  devfreq: exynos5: Use devm_devfreq_* function using device resource management

 drivers/devfreq/devfreq.c            | 125 ++++++++++++++++++++++++++++++++---
 drivers/devfreq/exynos/exynos4_bus.c |  19 ++----
 drivers/devfreq/exynos/exynos5_bus.c |  29 +++-----
 include/linux/devfreq.h              |  35 +++++++++-
 4 files changed, 161 insertions(+), 47 deletions(-)

-- 
1.8.0

[PATCHv2 1/5] devfreq: Fix devfreq_remove_device() to improve the sequence of resource free

[Chanwoo Choi]

This patch modify devfreq_remove_device() to improve the sequence of resource
free. If executing existing devfreq_remove_device(), this function always
executes _remove_devfreq() twice. In result, second _remove_devfreq() always
return error value. So, This patch resolves complicated function sequence
as following:

[Flow sequence before modification]
devfreq_remove_device()
   _remove_devfreq(devfreq, false)
      kfree(devfreq);  /* Free devfreq */
      if (!skip ...) { /* skip is false */
         device_unregister(&devfreq->dev)
         put_device(&devfreq->dev);
            ...
            dev->release()
               devfreq_dev_release()
                  _remove_devfreq(devfreq, true) <- Recall to free devfreq
                  /*
		   * Always return error without freeing resource because
		   * already _remove_devfreq() frees the memory of devfreq.
		   */
   }

[Flow sequence after modification]
devfreq_remove_device
   device_unregister(&devfreq->dev)
   put_device(&devfreq->dev);
      ..
      dev->release()
         devfreq_dev_release()
            _remove_devfreq()
               kfree(devfreq); /* Free devfreq */

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
 drivers/devfreq/devfreq.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index d32c8b6..e960eb0 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -437,7 +437,7 @@ update:
  * @devfreq:	the devfreq struct
  * @skip:	skip calling device_unregister().
  */
-static void _remove_devfreq(struct devfreq *devfreq, bool skip)
+static void _remove_devfreq(struct devfreq *devfreq)
 {
 	mutex_lock(&devfreq_list_lock);
 	if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) {
@@ -462,11 +462,6 @@ static void _remove_devfreq(struct devfreq *devfreq, bool skip)
 	if (devfreq->profile->exit)
 		devfreq->profile->exit(devfreq->dev.parent);
 
-	if (!skip && get_device(&devfreq->dev)) {
-		device_unregister(&devfreq->dev);
-		put_device(&devfreq->dev);
-	}
-
 	mutex_destroy(&devfreq->lock);
 	kfree(devfreq);
 }
@@ -476,14 +471,12 @@ static void _remove_devfreq(struct devfreq *devfreq, bool skip)
  * @dev:	the devfreq device
  *
  * This calls _remove_devfreq() if _remove_devfreq() is not called.
- * Note that devfreq_dev_release() could be called by _remove_devfreq() as
- * well as by others unregistering the device.
  */
 static void devfreq_dev_release(struct device *dev)
 {
 	struct devfreq *devfreq = to_devfreq(dev);
 
-	_remove_devfreq(devfreq, true);
+	_remove_devfreq(devfreq);
 }
 
 static int devfreq_qos_sanity_check(struct device *dev,
@@ -659,7 +652,8 @@ int devfreq_remove_device(struct devfreq *devfreq)
 	if (!devfreq)
 		return -EINVAL;
 
-	_remove_devfreq(devfreq, false);
+	device_unregister(&devfreq->dev);
+	put_device(&devfreq->dev);
 
 	return 0;
 }
-- 
1.8.0

[PATCHv2 2/5] devfreq: Add resource-managed function for devfreq device

[Chanwoo Choi]

This patch add resource-managed function for devfreq device as following
functions. The devm_devfreq_add_device() manages automatically the memory
of devfreq device using device resource management.
- devm_devfreq_add_device()
- devm_devfreq_remove_device()

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
 drivers/devfreq/devfreq.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/devfreq.h   | 21 +++++++++++++++-
 2 files changed, 83 insertions(+), 1 deletion(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index e960eb0..40fe650 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -659,6 +659,69 @@ int devfreq_remove_device(struct devfreq *devfreq)
 }
 EXPORT_SYMBOL(devfreq_remove_device);
 
+static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
+{
+	struct devfreq **r = res;
+
+	if (WARN_ON(!r || !*r))
+		return 0;
+
+	return *r == data;
+}
+
+static void devm_devfreq_dev_release(struct device *dev, void *res)
+{
+	devfreq_remove_device(*(struct devfreq **)res);
+}
+
+/**
+ * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
+ * @dev:	the device to add devfreq feature.
+ * @profile:	device-specific profile to run devfreq.
+ * @governor_name:	name of the policy to choose frequency.
+ * @data:	private data for the governor. The devfreq framework does not
+ *		touch this value.
+ *
+ * This function manages automatically the memory of devfreq device using device
+ * resource management and simplify the free operation for memory of devfreq
+ * device.
+ */
+struct devfreq *devm_devfreq_add_device(struct device *dev,
+					struct devfreq_dev_profile *profile,
+					const char *governor_name,
+					void *data)
+{
+	struct devfreq **ptr, *devfreq;
+
+	ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	devfreq = devfreq_add_device(dev, profile, governor_name, data);
+	if (IS_ERR(devfreq)) {
+		devres_free(ptr);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	*ptr = devfreq;
+	devres_add(dev, ptr);
+
+	return devfreq;
+}
+EXPORT_SYMBOL(devm_devfreq_add_device);
+
+/**
+ * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
+ * @dev:	the device to add devfreq feature.
+ * @devfreq:	the devfreq instance to be removed
+ */
+void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
+{
+	WARN_ON(devres_release(dev, devm_devfreq_dev_release,
+			       devm_devfreq_dev_match, devfreq));
+}
+EXPORT_SYMBOL(devm_devfreq_remove_device);
+
 /**
  * devfreq_suspend_device() - Suspend devfreq of a device.
  * @devfreq: the devfreq instance to be suspended
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 4dd8cca..3a5fbc3 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -223,6 +223,12 @@ extern struct devfreq *devfreq_add_device(struct device *dev,
 				  const char *governor_name,
 				  void *data);
 extern int devfreq_remove_device(struct devfreq *devfreq);
+extern struct devfreq *devm_devfreq_add_device(struct device *dev,
+				  struct devfreq_dev_profile *profile,
+				  const char *governor_name,
+				  void *data);
+extern void devm_devfreq_remove_device(struct device *dev,
+				  struct devfreq *devfreq);
 
 /* Supposed to be called by PM_SLEEP/PM_RUNTIME callbacks */
 extern int devfreq_suspend_device(struct devfreq *devfreq);
@@ -262,7 +268,7 @@ static inline struct devfreq *devfreq_add_device(struct device *dev,
 					  const char *governor_name,
 					  void *data)
 {
-	return NULL;
+	return ERR_PTR(-ENOSYS);
 }
 
 static inline int devfreq_remove_device(struct devfreq *devfreq)
@@ -270,6 +276,19 @@ static inline int devfreq_remove_device(struct devfreq *devfreq)
 	return 0;
 }
 
+static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
+					struct devfreq_dev_profile *profile,
+					const char *governor_name,
+					void *data)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline void devm_devfreq_remove_device(struct device *dev,
+					struct devfreq *devfreq)
+{
+}
+
 static inline int devfreq_suspend_device(struct devfreq *devfreq)
 {
 	return 0;
-- 
1.8.0

[PATCHv2 3/5] devfreq: Add devm_devfreq_{register,unregister}_opp_notfier function

[Chanwoo Choi]

This patch add resource-managed function for devfreq opp as following
functions. The devm_devfreq_register_opp_notifier() manages automatically
the registration of devfreq opp using device resource management.
- devm_devfreq_register_opp_notifier
- devm_devfreq_unregister_opp_notifier()

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
 drivers/devfreq/devfreq.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/devfreq.h   | 14 ++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 40fe650..6f5374cf 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1293,6 +1293,54 @@ int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
 	return ret;
 }
 
+static void devm_devfreq_opp_release(struct device *dev, void *res)
+{
+	devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
+}
+
+/**
+ * devm_ devfreq_register_opp_notifier()
+ *		- Resource-managed devfreq_register_opp_notifier()
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @devfreq:	The devfreq object.
+ */
+int devm_devfreq_register_opp_notifier(struct device *dev,
+				       struct devfreq *devfreq)
+{
+	struct devfreq **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = devfreq_register_opp_notifier(dev, devfreq);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	*ptr = devfreq;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
+
+/**
+ * devm_devfreq_unregister_opp_notifier()
+ *		- Resource-managed devfreq_unregister_opp_notifier()
+ * @dev:	The devfreq user device. (parent of devfreq)
+ * @devfreq:	The devfreq object.
+ */
+void devm_devfreq_unregister_opp_notifier(struct device *dev,
+					 struct devfreq *devfreq)
+{
+	WARN_ON(devres_release(dev, devm_devfreq_opp_release,
+			       devm_devfreq_dev_match, devfreq));
+}
+EXPORT_SYMBOL(devm_devfreq_unregister_opp_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 3a5fbc3..cf808d0 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -241,6 +241,10 @@ extern int devfreq_register_opp_notifier(struct device *dev,
 					 struct devfreq *devfreq);
 extern int devfreq_unregister_opp_notifier(struct device *dev,
 					   struct devfreq *devfreq);
+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);
 
 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
 /**
@@ -317,6 +321,16 @@ static inline int devfreq_unregister_opp_notifier(struct device *dev,
 	return -EINVAL;
 }
 
+static inline int devm_devfreq_register_opp_notifier(struct device *dev,
+						     struct devfreq *devfreq)
+{
+	return -EINVAL;
+}
+
+static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
+							struct devfreq *devfreq)
+{
+}
 #endif /* CONFIG_PM_DEVFREQ */
 
 #endif /* __LINUX_DEVFREQ_H__ */
-- 
1.8.0

[PATCHv2 4/5] devfreq: exynos4: Use devm_devfreq_* function using device resource management

[Chanwoo Choi]

This patch uses devm_devfreq_add_device()/devm_devfreq_register_opp_notifier()
to control automatically the resource of devfreq.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
---
 drivers/devfreq/exynos/exynos4_bus.c | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/drivers/devfreq/exynos/exynos4_bus.c b/drivers/devfreq/exynos/exynos4_bus.c
index d257f1f..bebb0a4 100644
--- a/drivers/devfreq/exynos/exynos4_bus.c
+++ b/drivers/devfreq/exynos/exynos4_bus.c
@@ -979,7 +979,7 @@ static int exynos4_busfreq_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, data);
 
-	data->devfreq = devfreq_add_device(dev, &exynos4_devfreq_profile,
+	data->devfreq = devm_devfreq_add_device(dev, &exynos4_devfreq_profile,
 					   "simple_ondemand", NULL);
 	if (IS_ERR(data->devfreq))
 		return PTR_ERR(data->devfreq);
@@ -991,27 +991,20 @@ static int exynos4_busfreq_probe(struct platform_device *pdev)
 	busfreq_mon_reset(ppmu_data);
 
 	/* Register opp_notifier for Exynos4 busfreq */
-	err = devfreq_register_opp_notifier(dev, data->devfreq);
+	err = devm_devfreq_register_opp_notifier(dev, data->devfreq);
 	if (err < 0) {
 		dev_err(dev, "Failed to register opp notifier\n");
-		goto err_notifier_opp;
+		return err;
 	}
 
 	/* Register pm_notifier for Exynos4 busfreq */
 	err = register_pm_notifier(&data->pm_notifier);
 	if (err) {
 		dev_err(dev, "Failed to setup pm notifier\n");
-		goto err_notifier_pm;
+		return err;
 	}
 
 	return 0;
-
-err_notifier_pm:
-	devfreq_unregister_opp_notifier(dev, data->devfreq);
-err_notifier_opp:
-	devfreq_remove_device(data->devfreq);
-
-	return err;
 }
 
 static int exynos4_busfreq_remove(struct platform_device *pdev)
@@ -1020,10 +1013,6 @@ static int exynos4_busfreq_remove(struct platform_device *pdev)
 
 	/* Unregister all of notifier chain */
 	unregister_pm_notifier(&data->pm_notifier);
-	devfreq_unregister_opp_notifier(data->dev, data->devfreq);
-
-	/* Remove devfreq instance */
-	devfreq_remove_device(data->devfreq);
 
 	return 0;
 }
-- 
1.8.0

[PATCHv2 5/5] devfreq: exynos5: Use devm_devfreq_* function using device resource management

[Chanwoo Choi]

This patch uses devm_devfreq_add_device()/devm_devfreq_register_opp_notifier()
to control automatically the resource of devfreq.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Manish Badarkhe <badarkhe.manish@gmail.com>
Cc: Abhilash Kesavan <a.kesavan@samsung.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
---
 drivers/devfreq/exynos/exynos5_bus.c | 29 ++++++++---------------------
 1 file changed, 8 insertions(+), 21 deletions(-)

diff --git a/drivers/devfreq/exynos/exynos5_bus.c b/drivers/devfreq/exynos/exynos5_bus.c
index ab54a69..6cd0392 100644
--- a/drivers/devfreq/exynos/exynos5_bus.c
+++ b/drivers/devfreq/exynos/exynos5_bus.c
@@ -163,21 +163,12 @@ static int exynos5_int_get_dev_status(struct device *dev,
 
 	return 0;
 }
-static void exynos5_int_exit(struct device *dev)
-{
-	struct platform_device *pdev = container_of(dev, struct platform_device,
-						    dev);
-	struct busfreq_data_int *data = platform_get_drvdata(pdev);
-
-	devfreq_unregister_opp_notifier(dev, data->devfreq);
-}
 
 static struct devfreq_dev_profile exynos5_devfreq_int_profile = {
 	.initial_freq		= 160000,
 	.polling_ms		= 100,
 	.target			= exynos5_busfreq_int_target,
 	.get_dev_status		= exynos5_int_get_dev_status,
-	.exit			= exynos5_int_exit,
 };
 
 static int exynos5250_init_int_tables(struct busfreq_data_int *data)
@@ -343,30 +334,27 @@ static int exynos5_busfreq_int_probe(struct platform_device *pdev)
 
 	busfreq_mon_reset(ppmu_data);
 
-	data->devfreq = devfreq_add_device(dev, &exynos5_devfreq_int_profile,
+	data->devfreq = devm_devfreq_add_device(dev, &exynos5_devfreq_int_profile,
 					   "simple_ondemand", NULL);
+	if (IS_ERR(data->devfreq))
+		return PTR_ERR(data->devfreq);
 
-	if (IS_ERR(data->devfreq)) {
-		err = PTR_ERR(data->devfreq);
-		goto err_devfreq_add;
+	err = devm_devfreq_register_opp_notifier(dev, data->devfreq);
+	if (err < 0) {
+		dev_err(dev, "Failed to register opp notifier\n");
+		return err;
 	}
 
-	devfreq_register_opp_notifier(dev, data->devfreq);
-
 	err = register_pm_notifier(&data->pm_notifier);
 	if (err) {
 		dev_err(dev, "Failed to setup pm notifier\n");
-		goto err_devfreq_add;
+		return err;
 	}
 
 	/* TODO: Add a new QOS class for int/mif bus */
 	pm_qos_add_request(&data->int_req, PM_QOS_NETWORK_THROUGHPUT, -1);
 
 	return 0;
-
-err_devfreq_add:
-	devfreq_remove_device(data->devfreq);
-	return err;
 }
 
 static int exynos5_busfreq_int_remove(struct platform_device *pdev)
@@ -375,7 +363,6 @@ static int exynos5_busfreq_int_remove(struct platform_device *pdev)
 
 	pm_qos_remove_request(&data->int_req);
 	unregister_pm_notifier(&data->pm_notifier);
-	devfreq_remove_device(data->devfreq);
 
 	return 0;
 }
-- 
1.8.0