[PATCH for v4.9-stable] reset: make optional functions really optional

[PATCH for v4.9-stable] reset: make optional functions really optional

[Dinh Nguyen]

From: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>

commit bb475230b8e59a547ab66ac3b02572df21a580e9 upstream.

The *_get_optional_* functions weren't really optional so this patch
makes them really optional.

These *_get_optional_* functions will now return NULL instead of an error
if no matching reset phandle is found in the DT, and all the
reset_control_* functions now accept NULL rstc pointers.

Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
---
Please apply to v4.9.y stable tree.
---
 drivers/reset/core.c  | 48 +++++++++++++++++++++++++++++++++----------
 include/linux/reset.h | 45 +++++++++++++++++++++++-----------------
 2 files changed, 63 insertions(+), 30 deletions(-)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index b8ae1dbd4c17..75821417b799 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -135,11 +135,16 @@ EXPORT_SYMBOL_GPL(devm_reset_controller_register);
  * @rstc: reset controller
  *
  * Calling this on a shared reset controller is an error.
+ *
+ * If rstc is NULL it is an optional reset and the function will just
+ * return 0.
  */
 int reset_control_reset(struct reset_control *rstc)
 {
-	if (WARN_ON(IS_ERR_OR_NULL(rstc)) ||
-	    WARN_ON(rstc->shared))
+	if (!rstc)
+		return 0;
+
+	if (WARN_ON(IS_ERR(rstc)))
 		return -EINVAL;
 
 	if (rstc->rcdev->ops->reset)
@@ -159,10 +164,16 @@ EXPORT_SYMBOL_GPL(reset_control_reset);
  *
  * For shared reset controls a driver cannot expect the hw's registers and
  * internal state to be reset, but must be prepared for this to happen.
+ *
+ * If rstc is NULL it is an optional reset and the function will just
+ * return 0.
  */
 int reset_control_assert(struct reset_control *rstc)
 {
-	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
+	if (!rstc)
+		return 0;
+
+	if (WARN_ON(IS_ERR(rstc)))
 		return -EINVAL;
 
 	if (!rstc->rcdev->ops->assert)
@@ -185,10 +196,16 @@ EXPORT_SYMBOL_GPL(reset_control_assert);
  * @rstc: reset controller
  *
  * After calling this function, the reset is guaranteed to be deasserted.
+ *
+ * If rstc is NULL it is an optional reset and the function will just
+ * return 0.
  */
 int reset_control_deassert(struct reset_control *rstc)
 {
-	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
+	if (!rstc)
+		return 0;
+
+	if (WARN_ON(IS_ERR(rstc)))
 		return -EINVAL;
 
 	if (!rstc->rcdev->ops->deassert)
@@ -206,12 +223,15 @@ EXPORT_SYMBOL_GPL(reset_control_deassert);
 /**
  * reset_control_status - returns a negative errno if not supported, a
  * positive value if the reset line is asserted, or zero if the reset
- * line is not asserted.
+ * line is not asserted or if the desc is NULL (optional reset).
  * @rstc: reset controller
  */
 int reset_control_status(struct reset_control *rstc)
 {
-	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
+	if (!rstc)
+		return 0;
+
+	if (WARN_ON(IS_ERR(rstc)))
 		return -EINVAL;
 
 	if (rstc->rcdev->ops->status)
@@ -268,7 +288,8 @@ static void __reset_control_put(struct reset_control *rstc)
 }
 
 struct reset_control *__of_reset_control_get(struct device_node *node,
-				     const char *id, int index, int shared)
+				     const char *id, int index, bool shared,
+				     bool optional)
 {
 	struct reset_control *rstc;
 	struct reset_controller_dev *r, *rcdev;
@@ -282,14 +303,18 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
 	if (id) {
 		index = of_property_match_string(node,
 						 "reset-names", id);
+		if (index == -EILSEQ)
+			return ERR_PTR(index);
 		if (index < 0)
-			return ERR_PTR(-ENOENT);
+			return optional ? NULL : ERR_PTR(-ENOENT);
 	}
 
 	ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
 					 index, &args);
-	if (ret)
+	if (ret == -EINVAL)
 		return ERR_PTR(ret);
+	if (ret)
+		return optional ? NULL : ERR_PTR(ret);
 
 	mutex_lock(&reset_list_mutex);
 	rcdev = NULL;
@@ -348,7 +373,8 @@ static void devm_reset_control_release(struct device *dev, void *res)
 }
 
 struct reset_control *__devm_reset_control_get(struct device *dev,
-				     const char *id, int index, int shared)
+				     const char *id, int index, bool shared,
+				     bool optional)
 {
 	struct reset_control **ptr, *rstc;
 
@@ -358,7 +384,7 @@ struct reset_control *__devm_reset_control_get(struct device *dev,
 		return ERR_PTR(-ENOMEM);
 
 	rstc = __of_reset_control_get(dev ? dev->of_node : NULL,
-				      id, index, shared);
+				      id, index, shared, optional);
 	if (!IS_ERR(rstc)) {
 		*ptr = rstc;
 		devres_add(dev, ptr);
diff --git a/include/linux/reset.h b/include/linux/reset.h
index 5daff15722d3..86b4ed75359e 100644
--- a/include/linux/reset.h
+++ b/include/linux/reset.h
@@ -13,10 +13,12 @@ int reset_control_deassert(struct reset_control *rstc);
 int reset_control_status(struct reset_control *rstc);
 
 struct reset_control *__of_reset_control_get(struct device_node *node,
-				     const char *id, int index, int shared);
+				     const char *id, int index, bool shared,
+				     bool optional);
 void reset_control_put(struct reset_control *rstc);
 struct reset_control *__devm_reset_control_get(struct device *dev,
-				     const char *id, int index, int shared);
+				     const char *id, int index, bool shared,
+				     bool optional);
 
 int __must_check device_reset(struct device *dev);
 
@@ -69,14 +71,15 @@ static inline int device_reset_optional(struct device *dev)
 
 static inline struct reset_control *__of_reset_control_get(
 					struct device_node *node,
-					const char *id, int index, int shared)
+					const char *id, int index, bool shared,
+					bool optional)
 {
 	return ERR_PTR(-ENOTSUPP);
 }
 
 static inline struct reset_control *__devm_reset_control_get(
-					struct device *dev,
-					const char *id, int index, int shared)
+					struct device *dev, const char *id,
+					int index, bool shared, bool optional)
 {
 	return ERR_PTR(-ENOTSUPP);
 }
@@ -104,7 +107,8 @@ __must_check reset_control_get_exclusive(struct device *dev, const char *id)
 #ifndef CONFIG_RESET_CONTROLLER
 	WARN_ON(1);
 #endif
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, false,
+									false);
 }
 
 /**
@@ -132,19 +136,22 @@ __must_check reset_control_get_exclusive(struct device *dev, const char *id)
 static inline struct reset_control *reset_control_get_shared(
 					struct device *dev, const char *id)
 {
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 1);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, true,
+									false);
 }
 
 static inline struct reset_control *reset_control_get_optional_exclusive(
 					struct device *dev, const char *id)
 {
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, false,
+									true);
 }
 
 static inline struct reset_control *reset_control_get_optional_shared(
 					struct device *dev, const char *id)
 {
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 1);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, true,
+									true);
 }
 
 /**
@@ -160,7 +167,7 @@ static inline struct reset_control *reset_control_get_optional_shared(
 static inline struct reset_control *of_reset_control_get_exclusive(
 				struct device_node *node, const char *id)
 {
-	return __of_reset_control_get(node, id, 0, 0);
+	return __of_reset_control_get(node, id, 0, false, false);
 }
 
 /**
@@ -185,7 +192,7 @@ static inline struct reset_control *of_reset_control_get_exclusive(
 static inline struct reset_control *of_reset_control_get_shared(
 				struct device_node *node, const char *id)
 {
-	return __of_reset_control_get(node, id, 0, 1);
+	return __of_reset_control_get(node, id, 0, true, false);
 }
 
 /**
@@ -202,7 +209,7 @@ static inline struct reset_control *of_reset_control_get_shared(
 static inline struct reset_control *of_reset_control_get_exclusive_by_index(
 					struct device_node *node, int index)
 {
-	return __of_reset_control_get(node, NULL, index, 0);
+	return __of_reset_control_get(node, NULL, index, false, false);
 }
 
 /**
@@ -230,7 +237,7 @@ static inline struct reset_control *of_reset_control_get_exclusive_by_index(
 static inline struct reset_control *of_reset_control_get_shared_by_index(
 					struct device_node *node, int index)
 {
-	return __of_reset_control_get(node, NULL, index, 1);
+	return __of_reset_control_get(node, NULL, index, true, false);
 }
 
 /**
@@ -252,7 +259,7 @@ __must_check devm_reset_control_get_exclusive(struct device *dev,
 #ifndef CONFIG_RESET_CONTROLLER
 	WARN_ON(1);
 #endif
-	return __devm_reset_control_get(dev, id, 0, 0);
+	return __devm_reset_control_get(dev, id, 0, false, false);
 }
 
 /**
@@ -267,19 +274,19 @@ __must_check devm_reset_control_get_exclusive(struct device *dev,
 static inline struct reset_control *devm_reset_control_get_shared(
 					struct device *dev, const char *id)
 {
-	return __devm_reset_control_get(dev, id, 0, 1);
+	return __devm_reset_control_get(dev, id, 0, true, false);
 }
 
 static inline struct reset_control *devm_reset_control_get_optional_exclusive(
 					struct device *dev, const char *id)
 {
-	return __devm_reset_control_get(dev, id, 0, 0);
+	return __devm_reset_control_get(dev, id, 0, false, true);
 }
 
 static inline struct reset_control *devm_reset_control_get_optional_shared(
 					struct device *dev, const char *id)
 {
-	return __devm_reset_control_get(dev, id, 0, 1);
+	return __devm_reset_control_get(dev, id, 0, true, true);
 }
 
 /**
@@ -297,7 +304,7 @@ static inline struct reset_control *devm_reset_control_get_optional_shared(
 static inline struct reset_control *
 devm_reset_control_get_exclusive_by_index(struct device *dev, int index)
 {
-	return __devm_reset_control_get(dev, NULL, index, 0);
+	return __devm_reset_control_get(dev, NULL, index, false, false);
 }
 
 /**
@@ -313,7 +320,7 @@ devm_reset_control_get_exclusive_by_index(struct device *dev, int index)
 static inline struct reset_control *
 devm_reset_control_get_shared_by_index(struct device *dev, int index)
 {
-	return __devm_reset_control_get(dev, NULL, index, 1);
+	return __devm_reset_control_get(dev, NULL, index, true, false);
 }
 
 /*
-- 
2.17.1

Re: [PATCH for v4.9-stable] reset: make optional functions really optional

[Sasha Levin]

On Mon, Dec 03, 2018 at 11:30:29AM -0600, Dinh Nguyen wrote:
>From: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
>
>commit bb475230b8e59a547ab66ac3b02572df21a580e9 upstream.
>
>The *_get_optional_* functions weren't really optional so this patch
>makes them really optional.
>
>These *_get_optional_* functions will now return NULL instead of an error
>if no matching reset phandle is found in the DT, and all the
>reset_control_* functions now accept NULL rstc pointers.
>
>Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
>Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
>---
>Please apply to v4.9.y stable tree.

The original commit had a few upstream fixes:

bb6c7768385b reset: remove remaining WARN_ON() in <linux/reset.h>
1554bbd4ad40 reset: make device_reset_optional() really optional
62e24c5775ec reset: add exported __reset_control_get, return NULL if optional
0ca10b60ceeb reset: fix optional reset_control_get stubs to return NULL
4891486fb2c8 reset: core: fix reset_control_put

We'll need to backport them to 4.9 as well if you backport this commit.

--
Thanks,
Sasha

Re: [PATCH for v4.9-stable] reset: make optional functions really optional

[Greg KH]

On Mon, Dec 03, 2018 at 11:30:29AM -0600, Dinh Nguyen wrote:
> From: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
> 
> commit bb475230b8e59a547ab66ac3b02572df21a580e9 upstream.
> 
> The *_get_optional_* functions weren't really optional so this patch
> makes them really optional.
> 
> These *_get_optional_* functions will now return NULL instead of an error
> if no matching reset phandle is found in the DT, and all the
> reset_control_* functions now accept NULL rstc pointers.
> 
> Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
> ---
> Please apply to v4.9.y stable tree.
> ---
>  drivers/reset/core.c  | 48 +++++++++++++++++++++++++++++++++----------
>  include/linux/reset.h | 45 +++++++++++++++++++++++-----------------
>  2 files changed, 63 insertions(+), 30 deletions(-)

What problem is this solving?  Why is this suddenly needed now?

thanks,

greg k-h

Re: [PATCH for v4.9-stable] reset: make optional functions really optional

[Dinh Nguyen]

On 12/3/18 11:45 AM, Greg KH wrote:
> On Mon, Dec 03, 2018 at 11:30:29AM -0600, Dinh Nguyen wrote:
>> From: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
>>
>> commit bb475230b8e59a547ab66ac3b02572df21a580e9 upstream.
>>
>> The *_get_optional_* functions weren't really optional so this patch
>> makes them really optional.
>>
>> These *_get_optional_* functions will now return NULL instead of an error
>> if no matching reset phandle is found in the DT, and all the
>> reset_control_* functions now accept NULL rstc pointers.
>>
>> Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
>> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
>> ---
>> Please apply to v4.9.y stable tree.
>> ---
>>  drivers/reset/core.c  | 48 +++++++++++++++++++++++++++++++++----------
>>  include/linux/reset.h | 45 +++++++++++++++++++++++-----------------
>>  2 files changed, 63 insertions(+), 30 deletions(-)
> 
> What problem is this solving?  Why is this suddenly needed now?
> 

The v4.9-stable branch has this patch for stmmac ethernet driver:

"6f37f7b62baa net: stmmac: socfpga: add additional ocp reset line for
Stratix10"

This patch calls devm_reset_control_get_optional(). This call ultimately
fails without optional reset patch, causing the ethernet driver to fail
to load.

Dinh

Re: [PATCH for v4.9-stable] reset: make optional functions really optional

[Dinh Nguyen]

On 12/3/18 11:44 AM, Sasha Levin wrote:
> On Mon, Dec 03, 2018 at 11:30:29AM -0600, Dinh Nguyen wrote:
>> From: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
>>
>> commit bb475230b8e59a547ab66ac3b02572df21a580e9 upstream.
>>
>> The *_get_optional_* functions weren't really optional so this patch
>> makes them really optional.
>>
>> These *_get_optional_* functions will now return NULL instead of an error
>> if no matching reset phandle is found in the DT, and all the
>> reset_control_* functions now accept NULL rstc pointers.
>>
>> Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
>> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
>> ---
>> Please apply to v4.9.y stable tree.
> 
> The original commit had a few upstream fixes:
> 
> bb6c7768385b reset: remove remaining WARN_ON() in <linux/reset.h>
> 1554bbd4ad40 reset: make device_reset_optional() really optional
> 62e24c5775ec reset: add exported __reset_control_get, return NULL if
> optional
> 0ca10b60ceeb reset: fix optional reset_control_get stubs to return NULL
> 4891486fb2c8 reset: core: fix reset_control_put
> 
> We'll need to backport them to 4.9 as well if you backport this commit.
> 

Hmm..I was able to fix an ethernet driver load issue by just backporting
this patch. Should I investigate backport of the other patches as well?

Dinh

Re: [PATCH for v4.9-stable] reset: make optional functions really optional

[Sasha Levin]

On Mon, Dec 03, 2018 at 12:31:59PM -0600, Dinh Nguyen wrote:
>
>
>On 12/3/18 11:44 AM, Sasha Levin wrote:
>> On Mon, Dec 03, 2018 at 11:30:29AM -0600, Dinh Nguyen wrote:
>>> From: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
>>>
>>> commit bb475230b8e59a547ab66ac3b02572df21a580e9 upstream.
>>>
>>> The *_get_optional_* functions weren't really optional so this patch
>>> makes them really optional.
>>>
>>> These *_get_optional_* functions will now return NULL instead of an error
>>> if no matching reset phandle is found in the DT, and all the
>>> reset_control_* functions now accept NULL rstc pointers.
>>>
>>> Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
>>> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
>>> ---
>>> Please apply to v4.9.y stable tree.
>>
>> The original commit had a few upstream fixes:
>>
>> bb6c7768385b reset: remove remaining WARN_ON() in <linux/reset.h>
>> 1554bbd4ad40 reset: make device_reset_optional() really optional
>> 62e24c5775ec reset: add exported __reset_control_get, return NULL if
>> optional
>> 0ca10b60ceeb reset: fix optional reset_control_get stubs to return NULL
>> 4891486fb2c8 reset: core: fix reset_control_put
>>
>> We'll need to backport them to 4.9 as well if you backport this commit.
>>
>
>Hmm..I was able to fix an ethernet driver load issue by just backporting
>this patch. Should I investigate backport of the other patches as well?

That patch will probably work on it's own, but if there are fixes for it
then they should be backported as well.

--
Thanks,
Sasha