[PATCH v3 0/2] media: qcom: camss: Re-structure camss_link_entities

[PATCH v3 0/2] media: qcom: camss: Re-structure camss_link_entities

[Vikram Sharma]

Refactor the camss_link_entities function by breaking it down into
three distinct functions. Each function will handle the linking of
a specific entity separately, enhancing readability.

Changes in V3:
- Broke down the change in 2 patches. first one to functionally
decompose link error message. second to restrcture the link
function.
- Removed the declarion of camss_link_error from header file.
- Link to v2: https://lore.kernel.org/linux-arm-msm/20241112133846.2397017-1-quic_vikramsa@quicinc.com/

Changes in V2:
- Declared variables in reverse christmas tree order.
- Functionally decomposed link error message.
- Link to v1: https://lore.kernel.org/linux-arm-msm/20241111173845.1773553-1-quic_vikramsa@quicinc.com/ 

  To: Robert Foss <rfoss@kernel.org>
  To: Todor Tomov <todor.too@gmail.com>
  To: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
  Cc: linux-media@vger.kernel.org
  Cc: linux-kernel@vger.kernel.org

Signed-off-by: Vikram Sharma <quic_vikramsa@quicinc.com>

Vikram Sharma (2):
  media: qcom: camss: reducing the repitious error message string
  media: qcom: camss: Restructure camss_link_entities

 drivers/media/platform/qcom/camss/camss.c | 195 ++++++++++++++--------
 1 file changed, 130 insertions(+), 65 deletions(-)

-- 
2.25.1

[PATCH v3 1/2] media: qcom: camss: reducing the repitious error message string

[Vikram Sharma]

Introducing a new function camss_link_err to avoid repition of
same error message, improving code maintainability.

Signed-off-by: Vikram Sharma <quic_vikramsa@quicinc.com>
---
 drivers/media/platform/qcom/camss/camss.c | 60 ++++++++++++++---------
 1 file changed, 37 insertions(+), 23 deletions(-)

diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
index 9fb31f4c18ad..520c5bc7a265 100644
--- a/drivers/media/platform/qcom/camss/camss.c
+++ b/drivers/media/platform/qcom/camss/camss.c
@@ -1993,6 +1993,26 @@ static int camss_init_subdevices(struct camss *camss)
 	return 0;
 }
 
+/*
+ * camss_link_entities - Register subdev nodes and create links
+ * camss_link_err - print error in case link creation fails
+ * @src_name: name for source of the link
+ * @sink_name: name for sink of the link
+ */
+inline void camss_link_err(struct camss *camss,
+			   const char *src_name,
+			   const char *sink_name,
+			   int ret)
+{
+	if (!camss || !src_name || !sink_name)
+		return;
+	dev_err(camss->dev,
+		"Failed to link %s->%s entities: %d\n",
+		src_name,
+		sink_name,
+		ret);
+}
+
 /*
  * camss_link_entities - Register subdev nodes and create links
  * @camss: CAMSS device
@@ -2012,11 +2032,10 @@ static int camss_link_entities(struct camss *camss)
 						    MSM_CSID_PAD_SINK,
 						    0);
 			if (ret < 0) {
-				dev_err(camss->dev,
-					"Failed to link %s->%s entities: %d\n",
-					camss->csiphy[i].subdev.entity.name,
-					camss->csid[j].subdev.entity.name,
-					ret);
+				camss_link_err(camss,
+					       camss->csiphy[i].subdev.entity.name,
+					       camss->csid[j].subdev.entity.name,
+					       ret);
 				return ret;
 			}
 		}
@@ -2031,11 +2050,10 @@ static int camss_link_entities(struct camss *camss)
 							    MSM_ISPIF_PAD_SINK,
 							    0);
 				if (ret < 0) {
-					dev_err(camss->dev,
-						"Failed to link %s->%s entities: %d\n",
-						camss->csid[i].subdev.entity.name,
-						camss->ispif->line[j].subdev.entity.name,
-						ret);
+					camss_link_err(camss, src_entity->name,
+						       camss->csid[i].subdev.entity.name,
+						       camss->ispif->line[j].subdev.entity.name,
+						       ret);
 					return ret;
 				}
 			}
@@ -2053,11 +2071,9 @@ static int camss_link_entities(struct camss *camss)
 								    MSM_VFE_PAD_SINK,
 								    0);
 					if (ret < 0) {
-						dev_err(camss->dev,
-							"Failed to link %s->%s entities: %d\n",
-							ispif->entity.name,
-							vfe->entity.name,
-							ret);
+						camss_link_err(camss, ispif->entity.name,
+							       vfe->entity.name,
+							       ret);
 						return ret;
 					}
 				}
@@ -2074,11 +2090,9 @@ static int camss_link_entities(struct camss *camss)
 								    MSM_VFE_PAD_SINK,
 								    0);
 					if (ret < 0) {
-						dev_err(camss->dev,
-							"Failed to link %s->%s entities: %d\n",
-							csid->entity.name,
-							vfe->entity.name,
-							ret);
+						camss_link_err(camss, csid->entity.name,
+							       vfe->entity.name,
+							       ret);
 						return ret;
 					}
 				}
@@ -2227,9 +2241,9 @@ static int camss_subdev_notifier_complete(struct v4l2_async_notifier *async)
 				input, MSM_CSIPHY_PAD_SINK,
 				MEDIA_LNK_FL_IMMUTABLE | MEDIA_LNK_FL_ENABLED);
 			if (ret < 0) {
-				dev_err(camss->dev,
-					"Failed to link %s->%s entities: %d\n",
-					sensor->name, input->name, ret);
+				camss_link_err(camss, sensor->name,
+					       input->name,
+					       ret);
 				return ret;
 			}
 		}
-- 
2.25.1

[PATCH v3 2/2] media: qcom: camss: Restructure camss_link_entities

[Vikram Sharma]

Refactor the camss_link_entities function by breaking it down into
three distinct functions. Each function will handle the linking of
a specific entity separately.
SC7280 and later targets mandates for 1:1 linking for csid -> vfe.
i.e. csid0 can be mapped to vfe0 only.

Signed-off-by: Suresh Vankadara <quic_svankada@quicinc.com>
Signed-off-by: Trishansh Bhardwaj <quic_tbhardwa@quicinc.com>
Signed-off-by: Vikram Sharma <quic_vikramsa@quicinc.com>
---
 drivers/media/platform/qcom/camss/camss.c | 155 ++++++++++++++--------
 1 file changed, 103 insertions(+), 52 deletions(-)

diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
index 520c5bc7a265..6ebf65019eed 100644
--- a/drivers/media/platform/qcom/camss/camss.c
+++ b/drivers/media/platform/qcom/camss/camss.c
@@ -1994,7 +1994,6 @@ static int camss_init_subdevices(struct camss *camss)
 }
 
 /*
- * camss_link_entities - Register subdev nodes and create links
  * camss_link_err - print error in case link creation fails
  * @src_name: name for source of the link
  * @sink_name: name for sink of the link
@@ -2014,14 +2013,64 @@ inline void camss_link_err(struct camss *camss,
 }
 
 /*
- * camss_link_entities - Register subdev nodes and create links
+ * camss_link_entities_csid - Register subdev nodes and create links
  * @camss: CAMSS device
  *
  * Return 0 on success or a negative error code on failure
  */
-static int camss_link_entities(struct camss *camss)
+static int camss_link_entities_csid(struct camss *camss)
 {
-	int i, j, k;
+	struct media_entity *src_entity;
+	struct media_entity *sink_entity;
+	int ret, line_num;
+	u16 sink_pad;
+	u16 src_pad;
+	int i, j;
+
+	for (i = 0; i < camss->res->csid_num; i++) {
+		if (camss->ispif)
+			line_num = camss->ispif->line_num;
+		else
+			line_num = camss->vfe[i].res->line_num;
+
+		src_entity = &camss->csid[i].subdev.entity;
+		for (j = 0; j < line_num; j++) {
+			if (camss->ispif) {
+				sink_entity = &camss->ispif->line[j].subdev.entity;
+				src_pad = MSM_CSID_PAD_SRC;
+				sink_pad = MSM_ISPIF_PAD_SINK;
+			} else {
+				sink_entity = &camss->vfe[i].line[j].subdev.entity;
+				src_pad = MSM_CSID_PAD_FIRST_SRC + j;
+				sink_pad = MSM_VFE_PAD_SINK;
+			}
+
+			ret = media_create_pad_link(src_entity,
+						    src_pad,
+						    sink_entity,
+						    sink_pad,
+						    0);
+			if (ret < 0) {
+				camss_link_err(camss, src_entity->name,
+					       sink_entity->name,
+					       ret);
+				return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * camss_link_entities_csiphy - Register subdev nodes and create links
+ * @camss: CAMSS device
+ *
+ * Return 0 on success or a negative error code on failure
+ */
+static int camss_link_entities_csiphy(struct camss *camss)
+{
+	int i, j;
 	int ret;
 
 	for (i = 0; i < camss->res->csiphy_num; i++) {
@@ -2041,66 +2090,68 @@ static int camss_link_entities(struct camss *camss)
 		}
 	}
 
-	if (camss->ispif) {
-		for (i = 0; i < camss->res->csid_num; i++) {
-			for (j = 0; j < camss->ispif->line_num; j++) {
-				ret = media_create_pad_link(&camss->csid[i].subdev.entity,
-							    MSM_CSID_PAD_SRC,
-							    &camss->ispif->line[j].subdev.entity,
-							    MSM_ISPIF_PAD_SINK,
+	return 0;
+}
+
+/*
+ * camss_link_entities_ispif - Register subdev nodes and create links
+ * @camss: CAMSS device
+ *
+ * Return 0 on success or a negative error code on failure
+ */
+static int camss_link_entities_ispif(struct camss *camss)
+{
+	int i, j, k;
+	int ret;
+
+	for (i = 0; i < camss->ispif->line_num; i++) {
+		for (k = 0; k < camss->res->vfe_num; k++) {
+			for (j = 0; j < camss->vfe[k].res->line_num; j++) {
+				struct v4l2_subdev *ispif = &camss->ispif->line[i].subdev;
+				struct v4l2_subdev *vfe = &camss->vfe[k].line[j].subdev;
+
+				ret = media_create_pad_link(&ispif->entity,
+							    MSM_ISPIF_PAD_SRC,
+							    &vfe->entity,
+							    MSM_VFE_PAD_SINK,
 							    0);
 				if (ret < 0) {
-					camss_link_err(camss, src_entity->name,
-						       camss->csid[i].subdev.entity.name,
-						       camss->ispif->line[j].subdev.entity.name,
+					camss_link_err(camss, ispif->entity.name,
+						       vfe->entity.name,
 						       ret);
 					return ret;
 				}
 			}
 		}
-
-		for (i = 0; i < camss->ispif->line_num; i++)
-			for (k = 0; k < camss->res->vfe_num; k++)
-				for (j = 0; j < camss->vfe[k].res->line_num; j++) {
-					struct v4l2_subdev *ispif = &camss->ispif->line[i].subdev;
-					struct v4l2_subdev *vfe = &camss->vfe[k].line[j].subdev;
-
-					ret = media_create_pad_link(&ispif->entity,
-								    MSM_ISPIF_PAD_SRC,
-								    &vfe->entity,
-								    MSM_VFE_PAD_SINK,
-								    0);
-					if (ret < 0) {
-						camss_link_err(camss, ispif->entity.name,
-							       vfe->entity.name,
-							       ret);
-						return ret;
-					}
-				}
-	} else {
-		for (i = 0; i < camss->res->csid_num; i++)
-			for (k = 0; k < camss->res->vfe_num; k++)
-				for (j = 0; j < camss->vfe[k].res->line_num; j++) {
-					struct v4l2_subdev *csid = &camss->csid[i].subdev;
-					struct v4l2_subdev *vfe = &camss->vfe[k].line[j].subdev;
-
-					ret = media_create_pad_link(&csid->entity,
-								    MSM_CSID_PAD_FIRST_SRC + j,
-								    &vfe->entity,
-								    MSM_VFE_PAD_SINK,
-								    0);
-					if (ret < 0) {
-						camss_link_err(camss, csid->entity.name,
-							       vfe->entity.name,
-							       ret);
-						return ret;
-					}
-				}
 	}
 
 	return 0;
 }
 
+/*
+ * camss_link_entities - Register subdev nodes and create links
+ * @camss: CAMSS device
+ *
+ * Return 0 on success or a negative error code on failure
+ */
+static int camss_link_entities(struct camss *camss)
+{
+	int ret;
+
+	ret = camss_link_entities_csiphy(camss);
+	if (ret < 0)
+		return ret;
+
+	ret = camss_link_entities_csid(camss);
+	if (ret < 0)
+		return ret;
+
+	if (camss->ispif)
+		ret = camss_link_entities_ispif(camss);
+
+	return ret;
+}
+
 /*
  * camss_register_entities - Register subdev nodes and create links
  * @camss: CAMSS device
-- 
2.25.1

Re: [PATCH v3 0/2] media: qcom: camss: Re-structure camss_link_entities

[Vladimir Zapolskiy]

Hi Vikram,

On 11/25/24 12:34, Vikram Sharma wrote:
> Refactor the camss_link_entities function by breaking it down into
> three distinct functions. Each function will handle the linking of
> a specific entity separately, enhancing readability.
> 
> Changes in V3:
> - Broke down the change in 2 patches. first one to functionally
> decompose link error message. second to restrcture the link
> function.
> - Removed the declarion of camss_link_error from header file.
> - Link to v2: https://lore.kernel.org/linux-arm-msm/20241112133846.2397017-1-quic_vikramsa@quicinc.com/

as I said last time I don't see the value of these changes.

Since the changes are non-functional, then hopefully there should be
no issues with them, however I really miss the point of adding 65
lines of code for a questionable reason and at the price of increased
complexity.

Is there a good reason not to drop the series?

> Changes in V2:
> - Declared variables in reverse christmas tree order.
> - Functionally decomposed link error message.
> - Link to v1: https://lore.kernel.org/linux-arm-msm/20241111173845.1773553-1-quic_vikramsa@quicinc.com/
> 
>    To: Robert Foss <rfoss@kernel.org>
>    To: Todor Tomov <todor.too@gmail.com>
>    To: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
>    Cc: linux-media@vger.kernel.org
>    Cc: linux-kernel@vger.kernel.org
> 
> Signed-off-by: Vikram Sharma <quic_vikramsa@quicinc.com>
> 
> Vikram Sharma (2):
>    media: qcom: camss: reducing the repitious error message string
>    media: qcom: camss: Restructure camss_link_entities
> 
>   drivers/media/platform/qcom/camss/camss.c | 195 ++++++++++++++--------
>   1 file changed, 130 insertions(+), 65 deletions(-)
> 

--
Best wishes,
Vladimir

Re: [PATCH v3 1/2] media: qcom: camss: reducing the repitious error message string

[Bryan O'Donoghue]

On 25/11/2024 10:34, Vikram Sharma wrote:
> Introducing a new function camss_link_err to avoid repition of
> same error message, improving code maintainability.
> 
> Signed-off-by: Vikram Sharma <quic_vikramsa@quicinc.com>
> ---
>   drivers/media/platform/qcom/camss/camss.c | 60 ++++++++++++++---------
>   1 file changed, 37 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
> index 9fb31f4c18ad..520c5bc7a265 100644
> --- a/drivers/media/platform/qcom/camss/camss.c
> +++ b/drivers/media/platform/qcom/camss/camss.c
> @@ -1993,6 +1993,26 @@ static int camss_init_subdevices(struct camss *camss)
>   	return 0;
>   }
>   
> +/*
> + * camss_link_entities - Register subdev nodes and create links
> + * camss_link_err - print error in case link creation fails
> + * @src_name: name for source of the link
> + * @sink_name: name for sink of the link
> + */
> +inline void camss_link_err(struct camss *camss,
> +			   const char *src_name,
> +			   const char *sink_name,
> +			   int ret)
> +{
> +	if (!camss || !src_name || !sink_name)
> +		return;

You don't need this defensive coding error check, please drop.

Once done you can add

Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>

Re: [PATCH v3 0/2] media: qcom: camss: Re-structure camss_link_entities

[Bryan O'Donoghue]

On 25/11/2024 11:57, Vladimir Zapolskiy wrote:
> Hi Vikram,
> 
> On 11/25/24 12:34, Vikram Sharma wrote:
>> Refactor the camss_link_entities function by breaking it down into
>> three distinct functions. Each function will handle the linking of
>> a specific entity separately, enhancing readability.
>>
>> Changes in V3:
>> - Broke down the change in 2 patches. first one to functionally
>> decompose link error message. second to restrcture the link
>> function.
>> - Removed the declarion of camss_link_error from header file.
>> - Link to v2: https://lore.kernel.org/linux-arm- 
>> msm/20241112133846.2397017-1-quic_vikramsa@quicinc.com/
> 
> as I said last time I don't see the value of these changes.
> 
> Since the changes are non-functional, then hopefully there should be
> no issues with them, however I really miss the point of adding 65
> lines of code for a questionable reason and at the price of increased
> complexity.
> 
> Is there a good reason not to drop the series?
I think there is value in both functional decomposition and tidying up 
code - for example removing circuitous if/elses in favour of more 
discreet and easy to read functions, so I'm inclined to accept this series.

---
bod