[PATCH] RFC: media: v4l2-subdev: add subdev-wide config struct

[PATCH] RFC: media: v4l2-subdev: add subdev-wide config struct

[Tomi Valkeinen]

We have 'struct v4l2_subdev_pad_config' which contains configuration for
a single pad used for the TRY functionality, and an array of those
structs is passed to various v4l2_subdev_pad_ops.

I was working on subdev internal routing between pads, and realized that
there's no way to add TRY functionality for routes, which is not pad
specific configuration. Adding a separate struct for try-route config
wouldn't work either, as e.g. set-fmt needs to know the try-route
configuration to propagate the settings.

This patch adds a new struct, 'struct v4l2_subdev_config' (which at the
moment only contains the v4l2_subdev_pad_config array) and the new
struct is used in most of the places where v4l2_subdev_pad_config was
used. All v4l2_subdev_pad_ops functions taking v4l2_subdev_pad_config
are changed to instead take v4l2_subdev_config.

Two drivers are changed to work with the above changes (drivers for HW
which I have) as an example.

I worked on a semantic patch (included below, my first spatch...) to do
this change to all drivers, but hit lots of problems with non-trivial
uses of v4l2_subdev_pad_config.

As it looks like substantial amount of manual work is needed, I'm
posting this RFC to get an ack on the changes before continuing that
work.

@ v4l2_subdev_pad_ops @
identifier pad_ops;
identifier func;
@@

(
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .enum_mbus_code = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .enum_frame_size = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .enum_frame_interval = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .get_fmt = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .set_fmt = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .get_selection = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .set_selection = func,
        ...,
};
|
static const struct v4l2_subdev_pad_ops pad_ops = {
        ...,
        .init_cfg = func,
        ...,
};
)

@@
identifier v4l2_subdev_pad_ops.func;
identifier sd;
identifier cfg;
@@

 func(struct v4l2_subdev *sd,
-	struct v4l2_subdev_pad_config *cfg,
+	struct v4l2_subdev_config *cfg,
	...
      )
 {
    ...
 }

@@
identifier v4l2_subdev_pad_ops.func;
identifier sd;
identifier cfg;
@@

 func(struct v4l2_subdev *sd,
-   struct v4l2_subdev_pad_config *cfg
+   struct v4l2_subdev_config *cfg
      )
 {
    ...
 }

@@
struct v4l2_subdev_fh *fh;
@@
-    fh->pad
+    &fh->cfg

@@
identifier func;
identifier cfg;
@@

func(...,
- struct v4l2_subdev_pad_config *cfg,
+ struct v4l2_subdev_config *cfg,
 ...)
{
    ...
}

@@
struct v4l2_subdev_config *cfg;
@@
 {
    <...
(
-   cfg->try_fmt
+   cfg->pad_configs->try_fmt
|
-   cfg->try_crop
+   cfg->pad_configs->try_crop
|
-   cfg->try_compose
+   cfg->pad_configs->try_compose
)
    ...>
 }

@@
identifier pad_cfg;
@@
{
    ...
    struct v4l2_subdev_pad_config pad_cfg;
+   struct v4l2_subdev_config cfg = { .pad_configs = &pad_cfg };
    <...
-   &pad_cfg
+   &cfg
    ...>
}

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/media/i2c/ov5640.c                   | 10 +--
 drivers/media/platform/ti-vpe/cal-camerarx.c | 12 +--
 drivers/media/v4l2-core/v4l2-subdev.c        | 85 ++++++++++----------
 include/media/v4l2-subdev.h                  | 49 +++++------
 4 files changed, 78 insertions(+), 78 deletions(-)

diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
index 14f3afa7721a..7c76c0754426 100644
--- a/drivers/media/i2c/ov5640.c
+++ b/drivers/media/i2c/ov5640.c
@@ -2227,7 +2227,7 @@ static int ov5640_try_frame_interval(struct ov5640_dev *sensor,
 }
 
 static int ov5640_get_fmt(struct v4l2_subdev *sd,
-			  struct v4l2_subdev_pad_config *cfg,
+			  struct v4l2_subdev_config *cfg,
 			  struct v4l2_subdev_format *format)
 {
 	struct ov5640_dev *sensor = to_ov5640_dev(sd);
@@ -2285,7 +2285,7 @@ static int ov5640_try_fmt_internal(struct v4l2_subdev *sd,
 }
 
 static int ov5640_set_fmt(struct v4l2_subdev *sd,
-			  struct v4l2_subdev_pad_config *cfg,
+			  struct v4l2_subdev_config *cfg,
 			  struct v4l2_subdev_format *format)
 {
 	struct ov5640_dev *sensor = to_ov5640_dev(sd);
@@ -2818,7 +2818,7 @@ static int ov5640_init_controls(struct ov5640_dev *sensor)
 }
 
 static int ov5640_enum_frame_size(struct v4l2_subdev *sd,
-				  struct v4l2_subdev_pad_config *cfg,
+				  struct v4l2_subdev_config *cfg,
 				  struct v4l2_subdev_frame_size_enum *fse)
 {
 	if (fse->pad != 0)
@@ -2838,7 +2838,7 @@ static int ov5640_enum_frame_size(struct v4l2_subdev *sd,
 
 static int ov5640_enum_frame_interval(
 	struct v4l2_subdev *sd,
-	struct v4l2_subdev_pad_config *cfg,
+	struct v4l2_subdev_config *cfg,
 	struct v4l2_subdev_frame_interval_enum *fie)
 {
 	struct ov5640_dev *sensor = to_ov5640_dev(sd);
@@ -2924,7 +2924,7 @@ static int ov5640_s_frame_interval(struct v4l2_subdev *sd,
 }
 
 static int ov5640_enum_mbus_code(struct v4l2_subdev *sd,
-				 struct v4l2_subdev_pad_config *cfg,
+				 struct v4l2_subdev_config *cfg,
 				 struct v4l2_subdev_mbus_code_enum *code)
 {
 	if (code->pad != 0)
diff --git a/drivers/media/platform/ti-vpe/cal-camerarx.c b/drivers/media/platform/ti-vpe/cal-camerarx.c
index cbe6114908de..c708c61f2188 100644
--- a/drivers/media/platform/ti-vpe/cal-camerarx.c
+++ b/drivers/media/platform/ti-vpe/cal-camerarx.c
@@ -586,7 +586,7 @@ static inline struct cal_camerarx *to_cal_camerarx(struct v4l2_subdev *sd)
 
 static struct v4l2_mbus_framefmt *
 cal_camerarx_get_pad_format(struct cal_camerarx *phy,
-			    struct v4l2_subdev_pad_config *cfg,
+			    struct v4l2_subdev_config *cfg,
 			    unsigned int pad, u32 which)
 {
 	switch (which) {
@@ -611,7 +611,7 @@ static int cal_camerarx_sd_s_stream(struct v4l2_subdev *sd, int enable)
 }
 
 static int cal_camerarx_sd_enum_mbus_code(struct v4l2_subdev *sd,
-					  struct v4l2_subdev_pad_config *cfg,
+					  struct v4l2_subdev_config *cfg,
 					  struct v4l2_subdev_mbus_code_enum *code)
 {
 	struct cal_camerarx *phy = to_cal_camerarx(sd);
@@ -639,7 +639,7 @@ static int cal_camerarx_sd_enum_mbus_code(struct v4l2_subdev *sd,
 }
 
 static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,
-					   struct v4l2_subdev_pad_config *cfg,
+					   struct v4l2_subdev_config *cfg,
 					   struct v4l2_subdev_frame_size_enum *fse)
 {
 	struct cal_camerarx *phy = to_cal_camerarx(sd);
@@ -679,7 +679,7 @@ static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,
 }
 
 static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,
-				   struct v4l2_subdev_pad_config *cfg,
+				   struct v4l2_subdev_config *cfg,
 				   struct v4l2_subdev_format *format)
 {
 	struct cal_camerarx *phy = to_cal_camerarx(sd);
@@ -692,7 +692,7 @@ static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,
 }
 
 static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
-				   struct v4l2_subdev_pad_config *cfg,
+				   struct v4l2_subdev_config *cfg,
 				   struct v4l2_subdev_format *format)
 {
 	struct cal_camerarx *phy = to_cal_camerarx(sd);
@@ -742,7 +742,7 @@ static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
 }
 
 static int cal_camerarx_sd_init_cfg(struct v4l2_subdev *sd,
-				    struct v4l2_subdev_pad_config *cfg)
+				    struct v4l2_subdev_config *cfg)
 {
 	struct v4l2_subdev_format format = {
 		.which = cfg ? V4L2_SUBDEV_FORMAT_TRY
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 956dafab43d4..248fa4ee9356 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -26,19 +26,18 @@
 #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
 static int subdev_fh_init(struct v4l2_subdev_fh *fh, struct v4l2_subdev *sd)
 {
-	if (sd->entity.num_pads) {
-		fh->pad = v4l2_subdev_alloc_pad_config(sd);
-		if (fh->pad == NULL)
-			return -ENOMEM;
-	}
+	int ret;
+
+	ret = v4l2_subdev_init_config(sd, &fh->cfg);
+	if (ret)
+		return ret;
 
 	return 0;
 }
 
 static void subdev_fh_free(struct v4l2_subdev_fh *fh)
 {
-	v4l2_subdev_free_pad_config(fh->pad);
-	fh->pad = NULL;
+	v4l2_subdev_uninit_config(&fh->cfg);
 }
 
 static int subdev_open(struct file *file)
@@ -146,7 +145,7 @@ static inline int check_pad(struct v4l2_subdev *sd, u32 pad)
 	return 0;
 }
 
-static int check_cfg(u32 which, struct v4l2_subdev_pad_config *cfg)
+static int check_cfg(u32 which, struct v4l2_subdev_config *cfg)
 {
 	if (which == V4L2_SUBDEV_FORMAT_TRY && !cfg)
 		return -EINVAL;
@@ -155,7 +154,7 @@ static int check_cfg(u32 which, struct v4l2_subdev_pad_config *cfg)
 }
 
 static inline int check_format(struct v4l2_subdev *sd,
-			       struct v4l2_subdev_pad_config *cfg,
+			       struct v4l2_subdev_config *cfg,
 			       struct v4l2_subdev_format *format)
 {
 	if (!format)
@@ -166,7 +165,7 @@ static inline int check_format(struct v4l2_subdev *sd,
 }
 
 static int call_get_fmt(struct v4l2_subdev *sd,
-			struct v4l2_subdev_pad_config *cfg,
+			struct v4l2_subdev_config *cfg,
 			struct v4l2_subdev_format *format)
 {
 	return check_format(sd, cfg, format) ? :
@@ -174,7 +173,7 @@ static int call_get_fmt(struct v4l2_subdev *sd,
 }
 
 static int call_set_fmt(struct v4l2_subdev *sd,
-			struct v4l2_subdev_pad_config *cfg,
+			struct v4l2_subdev_config *cfg,
 			struct v4l2_subdev_format *format)
 {
 	return check_format(sd, cfg, format) ? :
@@ -182,7 +181,7 @@ static int call_set_fmt(struct v4l2_subdev *sd,
 }
 
 static int call_enum_mbus_code(struct v4l2_subdev *sd,
-			       struct v4l2_subdev_pad_config *cfg,
+			       struct v4l2_subdev_config *cfg,
 			       struct v4l2_subdev_mbus_code_enum *code)
 {
 	if (!code)
@@ -194,7 +193,7 @@ static int call_enum_mbus_code(struct v4l2_subdev *sd,
 }
 
 static int call_enum_frame_size(struct v4l2_subdev *sd,
-				struct v4l2_subdev_pad_config *cfg,
+				struct v4l2_subdev_config *cfg,
 				struct v4l2_subdev_frame_size_enum *fse)
 {
 	if (!fse)
@@ -229,7 +228,7 @@ static int call_s_frame_interval(struct v4l2_subdev *sd,
 }
 
 static int call_enum_frame_interval(struct v4l2_subdev *sd,
-				    struct v4l2_subdev_pad_config *cfg,
+				    struct v4l2_subdev_config *cfg,
 				    struct v4l2_subdev_frame_interval_enum *fie)
 {
 	if (!fie)
@@ -241,7 +240,7 @@ static int call_enum_frame_interval(struct v4l2_subdev *sd,
 }
 
 static inline int check_selection(struct v4l2_subdev *sd,
-				  struct v4l2_subdev_pad_config *cfg,
+				  struct v4l2_subdev_config *cfg,
 				  struct v4l2_subdev_selection *sel)
 {
 	if (!sel)
@@ -252,7 +251,7 @@ static inline int check_selection(struct v4l2_subdev *sd,
 }
 
 static int call_get_selection(struct v4l2_subdev *sd,
-			      struct v4l2_subdev_pad_config *cfg,
+			      struct v4l2_subdev_config *cfg,
 			      struct v4l2_subdev_selection *sel)
 {
 	return check_selection(sd, cfg, sel) ? :
@@ -260,7 +259,7 @@ static int call_get_selection(struct v4l2_subdev *sd,
 }
 
 static int call_set_selection(struct v4l2_subdev *sd,
-			      struct v4l2_subdev_pad_config *cfg,
+			      struct v4l2_subdev_config *cfg,
 			      struct v4l2_subdev_selection *sel)
 {
 	return check_selection(sd, cfg, sel) ? :
@@ -506,7 +505,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 
 		memset(format->reserved, 0, sizeof(format->reserved));
 		memset(format->format.reserved, 0, sizeof(format->format.reserved));
-		return v4l2_subdev_call(sd, pad, get_fmt, subdev_fh->pad, format);
+		return v4l2_subdev_call(sd, pad, get_fmt, &subdev_fh->cfg, format);
 	}
 
 	case VIDIOC_SUBDEV_S_FMT: {
@@ -517,7 +516,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 
 		memset(format->reserved, 0, sizeof(format->reserved));
 		memset(format->format.reserved, 0, sizeof(format->format.reserved));
-		return v4l2_subdev_call(sd, pad, set_fmt, subdev_fh->pad, format);
+		return v4l2_subdev_call(sd, pad, set_fmt, &subdev_fh->cfg, format);
 	}
 
 	case VIDIOC_SUBDEV_G_CROP: {
@@ -531,7 +530,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		sel.target = V4L2_SEL_TGT_CROP;
 
 		rval = v4l2_subdev_call(
-			sd, pad, get_selection, subdev_fh->pad, &sel);
+			sd, pad, get_selection, &subdev_fh->cfg, &sel);
 
 		crop->rect = sel.r;
 
@@ -553,7 +552,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		sel.r = crop->rect;
 
 		rval = v4l2_subdev_call(
-			sd, pad, set_selection, subdev_fh->pad, &sel);
+			sd, pad, set_selection, &subdev_fh->cfg, &sel);
 
 		crop->rect = sel.r;
 
@@ -564,7 +563,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		struct v4l2_subdev_mbus_code_enum *code = arg;
 
 		memset(code->reserved, 0, sizeof(code->reserved));
-		return v4l2_subdev_call(sd, pad, enum_mbus_code, subdev_fh->pad,
+		return v4l2_subdev_call(sd, pad, enum_mbus_code, &subdev_fh->cfg,
 					code);
 	}
 
@@ -572,7 +571,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		struct v4l2_subdev_frame_size_enum *fse = arg;
 
 		memset(fse->reserved, 0, sizeof(fse->reserved));
-		return v4l2_subdev_call(sd, pad, enum_frame_size, subdev_fh->pad,
+		return v4l2_subdev_call(sd, pad, enum_frame_size, &subdev_fh->cfg,
 					fse);
 	}
 
@@ -597,7 +596,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		struct v4l2_subdev_frame_interval_enum *fie = arg;
 
 		memset(fie->reserved, 0, sizeof(fie->reserved));
-		return v4l2_subdev_call(sd, pad, enum_frame_interval, subdev_fh->pad,
+		return v4l2_subdev_call(sd, pad, enum_frame_interval, &subdev_fh->cfg,
 					fie);
 	}
 
@@ -606,7 +605,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 
 		memset(sel->reserved, 0, sizeof(sel->reserved));
 		return v4l2_subdev_call(
-			sd, pad, get_selection, subdev_fh->pad, sel);
+			sd, pad, get_selection, &subdev_fh->cfg, sel);
 	}
 
 	case VIDIOC_SUBDEV_S_SELECTION: {
@@ -617,7 +616,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 
 		memset(sel->reserved, 0, sizeof(sel->reserved));
 		return v4l2_subdev_call(
-			sd, pad, set_selection, subdev_fh->pad, sel);
+			sd, pad, set_selection, &subdev_fh->cfg, sel);
 	}
 
 	case VIDIOC_G_EDID: {
@@ -892,35 +891,35 @@ int v4l2_subdev_link_validate(struct media_link *link)
 }
 EXPORT_SYMBOL_GPL(v4l2_subdev_link_validate);
 
-struct v4l2_subdev_pad_config *
-v4l2_subdev_alloc_pad_config(struct v4l2_subdev *sd)
+int v4l2_subdev_init_config(struct v4l2_subdev *sd, struct v4l2_subdev_config *cfg)
 {
-	struct v4l2_subdev_pad_config *cfg;
 	int ret;
 
-	if (!sd->entity.num_pads)
-		return NULL;
-
-	cfg = kvmalloc_array(sd->entity.num_pads, sizeof(*cfg),
-			     GFP_KERNEL | __GFP_ZERO);
-	if (!cfg)
-		return NULL;
+	if (sd->entity.num_pads) {
+		cfg->pad_configs = kvmalloc_array(sd->entity.num_pads, sizeof(*cfg->pad_configs),
+				     GFP_KERNEL | __GFP_ZERO);
+		if (!cfg->pad_configs)
+			return -ENOMEM;
+	} else {
+		cfg->pad_configs = NULL;
+	}
 
 	ret = v4l2_subdev_call(sd, pad, init_cfg, cfg);
 	if (ret < 0 && ret != -ENOIOCTLCMD) {
-		kvfree(cfg);
-		return NULL;
+		kvfree(cfg->pad_configs);
+		return ret;
 	}
 
-	return cfg;
+	return 0;
 }
-EXPORT_SYMBOL_GPL(v4l2_subdev_alloc_pad_config);
+EXPORT_SYMBOL_GPL(v4l2_subdev_init_config);
 
-void v4l2_subdev_free_pad_config(struct v4l2_subdev_pad_config *cfg)
+void v4l2_subdev_uninit_config(struct v4l2_subdev_config *cfg)
 {
-	kvfree(cfg);
+	kvfree(cfg->pad_configs);
 }
-EXPORT_SYMBOL_GPL(v4l2_subdev_free_pad_config);
+EXPORT_SYMBOL_GPL(v4l2_subdev_uninit_config);
+
 #endif /* CONFIG_MEDIA_CONTROLLER */
 
 void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index d0e9a5bdb08b..1873e527987a 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -623,6 +623,10 @@ struct v4l2_subdev_pad_config {
 	struct v4l2_rect try_compose;
 };
 
+struct v4l2_subdev_config {
+	struct v4l2_subdev_pad_config *pad_configs;
+};
+
 /**
  * struct v4l2_subdev_pad_ops - v4l2-subdev pad level operations
  *
@@ -687,27 +691,27 @@ struct v4l2_subdev_pad_config {
  */
 struct v4l2_subdev_pad_ops {
 	int (*init_cfg)(struct v4l2_subdev *sd,
-			struct v4l2_subdev_pad_config *cfg);
+			struct v4l2_subdev_config *cfg);
 	int (*enum_mbus_code)(struct v4l2_subdev *sd,
-			      struct v4l2_subdev_pad_config *cfg,
+			      struct v4l2_subdev_config *cfg,
 			      struct v4l2_subdev_mbus_code_enum *code);
 	int (*enum_frame_size)(struct v4l2_subdev *sd,
-			       struct v4l2_subdev_pad_config *cfg,
+			       struct v4l2_subdev_config *cfg,
 			       struct v4l2_subdev_frame_size_enum *fse);
 	int (*enum_frame_interval)(struct v4l2_subdev *sd,
-				   struct v4l2_subdev_pad_config *cfg,
+				   struct v4l2_subdev_config *cfg,
 				   struct v4l2_subdev_frame_interval_enum *fie);
 	int (*get_fmt)(struct v4l2_subdev *sd,
-		       struct v4l2_subdev_pad_config *cfg,
+		       struct v4l2_subdev_config *cfg,
 		       struct v4l2_subdev_format *format);
 	int (*set_fmt)(struct v4l2_subdev *sd,
-		       struct v4l2_subdev_pad_config *cfg,
+		       struct v4l2_subdev_config *cfg,
 		       struct v4l2_subdev_format *format);
 	int (*get_selection)(struct v4l2_subdev *sd,
-			     struct v4l2_subdev_pad_config *cfg,
+			     struct v4l2_subdev_config *cfg,
 			     struct v4l2_subdev_selection *sel);
 	int (*set_selection)(struct v4l2_subdev *sd,
-			     struct v4l2_subdev_pad_config *cfg,
+			     struct v4l2_subdev_config *cfg,
 			     struct v4l2_subdev_selection *sel);
 	int (*get_edid)(struct v4l2_subdev *sd, struct v4l2_edid *edid);
 	int (*set_edid)(struct v4l2_subdev *sd, struct v4l2_edid *edid);
@@ -925,7 +929,7 @@ struct v4l2_subdev_fh {
 	struct v4l2_fh vfh;
 	struct module *owner;
 #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
-	struct v4l2_subdev_pad_config *pad;
+	struct v4l2_subdev_config cfg;
 #endif
 };
 
@@ -950,12 +954,12 @@ struct v4l2_subdev_fh {
  */
 static inline struct v4l2_mbus_framefmt *
 v4l2_subdev_get_try_format(struct v4l2_subdev *sd,
-			   struct v4l2_subdev_pad_config *cfg,
+			   struct v4l2_subdev_config *cfg,
 			   unsigned int pad)
 {
 	if (WARN_ON(pad >= sd->entity.num_pads))
 		pad = 0;
-	return &cfg[pad].try_fmt;
+	return &cfg->pad_configs[pad].try_fmt;
 }
 
 /**
@@ -968,12 +972,12 @@ v4l2_subdev_get_try_format(struct v4l2_subdev *sd,
  */
 static inline struct v4l2_rect *
 v4l2_subdev_get_try_crop(struct v4l2_subdev *sd,
-			 struct v4l2_subdev_pad_config *cfg,
+			 struct v4l2_subdev_config *cfg,
 			 unsigned int pad)
 {
 	if (WARN_ON(pad >= sd->entity.num_pads))
 		pad = 0;
-	return &cfg[pad].try_crop;
+	return &cfg->pad_configs[pad].try_crop;
 }
 
 /**
@@ -986,12 +990,12 @@ v4l2_subdev_get_try_crop(struct v4l2_subdev *sd,
  */
 static inline struct v4l2_rect *
 v4l2_subdev_get_try_compose(struct v4l2_subdev *sd,
-			    struct v4l2_subdev_pad_config *cfg,
+			    struct v4l2_subdev_config *cfg,
 			    unsigned int pad)
 {
 	if (WARN_ON(pad >= sd->entity.num_pads))
 		pad = 0;
-	return &cfg[pad].try_compose;
+	return &cfg->pad_configs[pad].try_compose;
 }
 
 #endif
@@ -1093,20 +1097,17 @@ int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd,
 int v4l2_subdev_link_validate(struct media_link *link);
 
 /**
- * v4l2_subdev_alloc_pad_config - Allocates memory for pad config
+ * v4l2_subdev_init_config - initialize v4l2_subdev_config
  *
- * @sd: pointer to struct v4l2_subdev
+ * Must call v4l2_subdev_uninit_config() when config is no longer needed.
  */
-struct
-v4l2_subdev_pad_config *v4l2_subdev_alloc_pad_config(struct v4l2_subdev *sd);
+int v4l2_subdev_init_config(struct v4l2_subdev *sd, struct v4l2_subdev_config *cfg);
 
 /**
- * v4l2_subdev_free_pad_config - Frees memory allocated by
- *	v4l2_subdev_alloc_pad_config().
- *
- * @cfg: pointer to &struct v4l2_subdev_pad_config
+ * v4l2_subdev_uninit_config - uninitialize v4l2_subdev_config
  */
-void v4l2_subdev_free_pad_config(struct v4l2_subdev_pad_config *cfg);
+void v4l2_subdev_uninit_config(struct v4l2_subdev_config *cfg);
+
 #endif /* CONFIG_MEDIA_CONTROLLER */
 
 /**
-- 
2.25.1

Re: [PATCH] RFC: media: v4l2-subdev: add subdev-wide config struct

[Laurent Pinchart]

Hi Tomi,

Thank you for the patch.

Hans, Sakari, could you share your opinion on this ? I see lots of
potential in this proposal (both for bikeshedding, and for actual
value). We need an ack on the concept, and likely naming scheme too,
before developing a final patch, as it's lots of churn in lots of
drivers.

On Fri, Apr 09, 2021 at 04:36:59PM +0300, Tomi Valkeinen wrote:
> We have 'struct v4l2_subdev_pad_config' which contains configuration for
> a single pad used for the TRY functionality, and an array of those
> structs is passed to various v4l2_subdev_pad_ops.
> 
> I was working on subdev internal routing between pads, and realized that
> there's no way to add TRY functionality for routes, which is not pad
> specific configuration. Adding a separate struct for try-route config
> wouldn't work either, as e.g. set-fmt needs to know the try-route
> configuration to propagate the settings.
> 
> This patch adds a new struct, 'struct v4l2_subdev_config' (which at the
> moment only contains the v4l2_subdev_pad_config array) and the new
> struct is used in most of the places where v4l2_subdev_pad_config was
> used. All v4l2_subdev_pad_ops functions taking v4l2_subdev_pad_config
> are changed to instead take v4l2_subdev_config.
> 
> Two drivers are changed to work with the above changes (drivers for HW
> which I have) as an example.
> 
> I worked on a semantic patch (included below, my first spatch...) to do
> this change to all drivers, but hit lots of problems with non-trivial
> uses of v4l2_subdev_pad_config.
> 
> As it looks like substantial amount of manual work is needed, I'm
> posting this RFC to get an ack on the changes before continuing that
> work.
> 
> @ v4l2_subdev_pad_ops @
> identifier pad_ops;
> identifier func;
> @@
> 
> (
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .enum_mbus_code = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .enum_frame_size = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .enum_frame_interval = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .get_fmt = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .set_fmt = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .get_selection = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .set_selection = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .init_cfg = func,
>         ...,
> };
> )
> 
> @@
> identifier v4l2_subdev_pad_ops.func;
> identifier sd;
> identifier cfg;
> @@
> 
>  func(struct v4l2_subdev *sd,
> -	struct v4l2_subdev_pad_config *cfg,
> +	struct v4l2_subdev_config *cfg,
> 	...
>       )
>  {
>     ...
>  }
> 
> @@
> identifier v4l2_subdev_pad_ops.func;
> identifier sd;
> identifier cfg;
> @@
> 
>  func(struct v4l2_subdev *sd,
> -   struct v4l2_subdev_pad_config *cfg
> +   struct v4l2_subdev_config *cfg
>       )
>  {
>     ...
>  }
> 
> @@
> struct v4l2_subdev_fh *fh;
> @@
> -    fh->pad
> +    &fh->cfg
> 
> @@
> identifier func;
> identifier cfg;
> @@
> 
> func(...,
> - struct v4l2_subdev_pad_config *cfg,
> + struct v4l2_subdev_config *cfg,
>  ...)
> {
>     ...
> }
> 
> @@
> struct v4l2_subdev_config *cfg;
> @@
>  {
>     <...
> (
> -   cfg->try_fmt
> +   cfg->pad_configs->try_fmt
> |
> -   cfg->try_crop
> +   cfg->pad_configs->try_crop
> |
> -   cfg->try_compose
> +   cfg->pad_configs->try_compose
> )
>     ...>
>  }
> 
> @@
> identifier pad_cfg;
> @@
> {
>     ...
>     struct v4l2_subdev_pad_config pad_cfg;
> +   struct v4l2_subdev_config cfg = { .pad_configs = &pad_cfg };
>     <...
> -   &pad_cfg
> +   &cfg
>     ...>
> }
> 

This doesn't look too bad (although the last change seems a bit weird),
but I suppose it's not the whole story, as you've mentioned above.

> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  drivers/media/i2c/ov5640.c                   | 10 +--
>  drivers/media/platform/ti-vpe/cal-camerarx.c | 12 +--
>  drivers/media/v4l2-core/v4l2-subdev.c        | 85 ++++++++++----------
>  include/media/v4l2-subdev.h                  | 49 +++++------
>  4 files changed, 78 insertions(+), 78 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
> index 14f3afa7721a..7c76c0754426 100644
> --- a/drivers/media/i2c/ov5640.c
> +++ b/drivers/media/i2c/ov5640.c
> @@ -2227,7 +2227,7 @@ static int ov5640_try_frame_interval(struct ov5640_dev *sensor,
>  }
>  
>  static int ov5640_get_fmt(struct v4l2_subdev *sd,
> -			  struct v4l2_subdev_pad_config *cfg,
> +			  struct v4l2_subdev_config *cfg,
>  			  struct v4l2_subdev_format *format)
>  {
>  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> @@ -2285,7 +2285,7 @@ static int ov5640_try_fmt_internal(struct v4l2_subdev *sd,
>  }
>  
>  static int ov5640_set_fmt(struct v4l2_subdev *sd,
> -			  struct v4l2_subdev_pad_config *cfg,
> +			  struct v4l2_subdev_config *cfg,
>  			  struct v4l2_subdev_format *format)
>  {
>  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> @@ -2818,7 +2818,7 @@ static int ov5640_init_controls(struct ov5640_dev *sensor)
>  }
>  
>  static int ov5640_enum_frame_size(struct v4l2_subdev *sd,
> -				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_config *cfg,
>  				  struct v4l2_subdev_frame_size_enum *fse)
>  {
>  	if (fse->pad != 0)
> @@ -2838,7 +2838,7 @@ static int ov5640_enum_frame_size(struct v4l2_subdev *sd,
>  
>  static int ov5640_enum_frame_interval(
>  	struct v4l2_subdev *sd,
> -	struct v4l2_subdev_pad_config *cfg,
> +	struct v4l2_subdev_config *cfg,
>  	struct v4l2_subdev_frame_interval_enum *fie)
>  {
>  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> @@ -2924,7 +2924,7 @@ static int ov5640_s_frame_interval(struct v4l2_subdev *sd,
>  }
>  
>  static int ov5640_enum_mbus_code(struct v4l2_subdev *sd,
> -				 struct v4l2_subdev_pad_config *cfg,
> +				 struct v4l2_subdev_config *cfg,
>  				 struct v4l2_subdev_mbus_code_enum *code)
>  {
>  	if (code->pad != 0)
> diff --git a/drivers/media/platform/ti-vpe/cal-camerarx.c b/drivers/media/platform/ti-vpe/cal-camerarx.c
> index cbe6114908de..c708c61f2188 100644
> --- a/drivers/media/platform/ti-vpe/cal-camerarx.c
> +++ b/drivers/media/platform/ti-vpe/cal-camerarx.c
> @@ -586,7 +586,7 @@ static inline struct cal_camerarx *to_cal_camerarx(struct v4l2_subdev *sd)
>  
>  static struct v4l2_mbus_framefmt *
>  cal_camerarx_get_pad_format(struct cal_camerarx *phy,
> -			    struct v4l2_subdev_pad_config *cfg,
> +			    struct v4l2_subdev_config *cfg,
>  			    unsigned int pad, u32 which)
>  {
>  	switch (which) {
> @@ -611,7 +611,7 @@ static int cal_camerarx_sd_s_stream(struct v4l2_subdev *sd, int enable)
>  }
>  
>  static int cal_camerarx_sd_enum_mbus_code(struct v4l2_subdev *sd,
> -					  struct v4l2_subdev_pad_config *cfg,
> +					  struct v4l2_subdev_config *cfg,
>  					  struct v4l2_subdev_mbus_code_enum *code)
>  {
>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
> @@ -639,7 +639,7 @@ static int cal_camerarx_sd_enum_mbus_code(struct v4l2_subdev *sd,
>  }
>  
>  static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,
> -					   struct v4l2_subdev_pad_config *cfg,
> +					   struct v4l2_subdev_config *cfg,
>  					   struct v4l2_subdev_frame_size_enum *fse)
>  {
>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
> @@ -679,7 +679,7 @@ static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,
>  }
>  
>  static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,
> -				   struct v4l2_subdev_pad_config *cfg,
> +				   struct v4l2_subdev_config *cfg,
>  				   struct v4l2_subdev_format *format)
>  {
>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
> @@ -692,7 +692,7 @@ static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,
>  }
>  
>  static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
> -				   struct v4l2_subdev_pad_config *cfg,
> +				   struct v4l2_subdev_config *cfg,
>  				   struct v4l2_subdev_format *format)
>  {
>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
> @@ -742,7 +742,7 @@ static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
>  }
>  
>  static int cal_camerarx_sd_init_cfg(struct v4l2_subdev *sd,
> -				    struct v4l2_subdev_pad_config *cfg)
> +				    struct v4l2_subdev_config *cfg)
>  {
>  	struct v4l2_subdev_format format = {
>  		.which = cfg ? V4L2_SUBDEV_FORMAT_TRY
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 956dafab43d4..248fa4ee9356 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -26,19 +26,18 @@
>  #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
>  static int subdev_fh_init(struct v4l2_subdev_fh *fh, struct v4l2_subdev *sd)
>  {
> -	if (sd->entity.num_pads) {
> -		fh->pad = v4l2_subdev_alloc_pad_config(sd);
> -		if (fh->pad == NULL)
> -			return -ENOMEM;
> -	}
> +	int ret;
> +
> +	ret = v4l2_subdev_init_config(sd, &fh->cfg);
> +	if (ret)
> +		return ret;
>  
>  	return 0;
>  }
>  
>  static void subdev_fh_free(struct v4l2_subdev_fh *fh)
>  {
> -	v4l2_subdev_free_pad_config(fh->pad);
> -	fh->pad = NULL;
> +	v4l2_subdev_uninit_config(&fh->cfg);
>  }
>  
>  static int subdev_open(struct file *file)
> @@ -146,7 +145,7 @@ static inline int check_pad(struct v4l2_subdev *sd, u32 pad)
>  	return 0;
>  }
>  
> -static int check_cfg(u32 which, struct v4l2_subdev_pad_config *cfg)
> +static int check_cfg(u32 which, struct v4l2_subdev_config *cfg)
>  {
>  	if (which == V4L2_SUBDEV_FORMAT_TRY && !cfg)
>  		return -EINVAL;
> @@ -155,7 +154,7 @@ static int check_cfg(u32 which, struct v4l2_subdev_pad_config *cfg)
>  }
>  
>  static inline int check_format(struct v4l2_subdev *sd,
> -			       struct v4l2_subdev_pad_config *cfg,
> +			       struct v4l2_subdev_config *cfg,
>  			       struct v4l2_subdev_format *format)
>  {
>  	if (!format)
> @@ -166,7 +165,7 @@ static inline int check_format(struct v4l2_subdev *sd,
>  }
>  
>  static int call_get_fmt(struct v4l2_subdev *sd,
> -			struct v4l2_subdev_pad_config *cfg,
> +			struct v4l2_subdev_config *cfg,
>  			struct v4l2_subdev_format *format)
>  {
>  	return check_format(sd, cfg, format) ? :
> @@ -174,7 +173,7 @@ static int call_get_fmt(struct v4l2_subdev *sd,
>  }
>  
>  static int call_set_fmt(struct v4l2_subdev *sd,
> -			struct v4l2_subdev_pad_config *cfg,
> +			struct v4l2_subdev_config *cfg,
>  			struct v4l2_subdev_format *format)
>  {
>  	return check_format(sd, cfg, format) ? :
> @@ -182,7 +181,7 @@ static int call_set_fmt(struct v4l2_subdev *sd,
>  }
>  
>  static int call_enum_mbus_code(struct v4l2_subdev *sd,
> -			       struct v4l2_subdev_pad_config *cfg,
> +			       struct v4l2_subdev_config *cfg,
>  			       struct v4l2_subdev_mbus_code_enum *code)
>  {
>  	if (!code)
> @@ -194,7 +193,7 @@ static int call_enum_mbus_code(struct v4l2_subdev *sd,
>  }
>  
>  static int call_enum_frame_size(struct v4l2_subdev *sd,
> -				struct v4l2_subdev_pad_config *cfg,
> +				struct v4l2_subdev_config *cfg,
>  				struct v4l2_subdev_frame_size_enum *fse)
>  {
>  	if (!fse)
> @@ -229,7 +228,7 @@ static int call_s_frame_interval(struct v4l2_subdev *sd,
>  }
>  
>  static int call_enum_frame_interval(struct v4l2_subdev *sd,
> -				    struct v4l2_subdev_pad_config *cfg,
> +				    struct v4l2_subdev_config *cfg,
>  				    struct v4l2_subdev_frame_interval_enum *fie)
>  {
>  	if (!fie)
> @@ -241,7 +240,7 @@ static int call_enum_frame_interval(struct v4l2_subdev *sd,
>  }
>  
>  static inline int check_selection(struct v4l2_subdev *sd,
> -				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_config *cfg,
>  				  struct v4l2_subdev_selection *sel)
>  {
>  	if (!sel)
> @@ -252,7 +251,7 @@ static inline int check_selection(struct v4l2_subdev *sd,
>  }
>  
>  static int call_get_selection(struct v4l2_subdev *sd,
> -			      struct v4l2_subdev_pad_config *cfg,
> +			      struct v4l2_subdev_config *cfg,
>  			      struct v4l2_subdev_selection *sel)
>  {
>  	return check_selection(sd, cfg, sel) ? :
> @@ -260,7 +259,7 @@ static int call_get_selection(struct v4l2_subdev *sd,
>  }
>  
>  static int call_set_selection(struct v4l2_subdev *sd,
> -			      struct v4l2_subdev_pad_config *cfg,
> +			      struct v4l2_subdev_config *cfg,
>  			      struct v4l2_subdev_selection *sel)
>  {
>  	return check_selection(sd, cfg, sel) ? :
> @@ -506,7 +505,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  
>  		memset(format->reserved, 0, sizeof(format->reserved));
>  		memset(format->format.reserved, 0, sizeof(format->format.reserved));
> -		return v4l2_subdev_call(sd, pad, get_fmt, subdev_fh->pad, format);
> +		return v4l2_subdev_call(sd, pad, get_fmt, &subdev_fh->cfg, format);
>  	}
>  
>  	case VIDIOC_SUBDEV_S_FMT: {
> @@ -517,7 +516,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  
>  		memset(format->reserved, 0, sizeof(format->reserved));
>  		memset(format->format.reserved, 0, sizeof(format->format.reserved));
> -		return v4l2_subdev_call(sd, pad, set_fmt, subdev_fh->pad, format);
> +		return v4l2_subdev_call(sd, pad, set_fmt, &subdev_fh->cfg, format);
>  	}
>  
>  	case VIDIOC_SUBDEV_G_CROP: {
> @@ -531,7 +530,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  		sel.target = V4L2_SEL_TGT_CROP;
>  
>  		rval = v4l2_subdev_call(
> -			sd, pad, get_selection, subdev_fh->pad, &sel);
> +			sd, pad, get_selection, &subdev_fh->cfg, &sel);
>  
>  		crop->rect = sel.r;
>  
> @@ -553,7 +552,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  		sel.r = crop->rect;
>  
>  		rval = v4l2_subdev_call(
> -			sd, pad, set_selection, subdev_fh->pad, &sel);
> +			sd, pad, set_selection, &subdev_fh->cfg, &sel);
>  
>  		crop->rect = sel.r;
>  
> @@ -564,7 +563,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  		struct v4l2_subdev_mbus_code_enum *code = arg;
>  
>  		memset(code->reserved, 0, sizeof(code->reserved));
> -		return v4l2_subdev_call(sd, pad, enum_mbus_code, subdev_fh->pad,
> +		return v4l2_subdev_call(sd, pad, enum_mbus_code, &subdev_fh->cfg,
>  					code);
>  	}
>  
> @@ -572,7 +571,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  		struct v4l2_subdev_frame_size_enum *fse = arg;
>  
>  		memset(fse->reserved, 0, sizeof(fse->reserved));
> -		return v4l2_subdev_call(sd, pad, enum_frame_size, subdev_fh->pad,
> +		return v4l2_subdev_call(sd, pad, enum_frame_size, &subdev_fh->cfg,
>  					fse);
>  	}
>  
> @@ -597,7 +596,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  		struct v4l2_subdev_frame_interval_enum *fie = arg;
>  
>  		memset(fie->reserved, 0, sizeof(fie->reserved));
> -		return v4l2_subdev_call(sd, pad, enum_frame_interval, subdev_fh->pad,
> +		return v4l2_subdev_call(sd, pad, enum_frame_interval, &subdev_fh->cfg,
>  					fie);
>  	}
>  
> @@ -606,7 +605,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  
>  		memset(sel->reserved, 0, sizeof(sel->reserved));
>  		return v4l2_subdev_call(
> -			sd, pad, get_selection, subdev_fh->pad, sel);
> +			sd, pad, get_selection, &subdev_fh->cfg, sel);
>  	}
>  
>  	case VIDIOC_SUBDEV_S_SELECTION: {
> @@ -617,7 +616,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  
>  		memset(sel->reserved, 0, sizeof(sel->reserved));
>  		return v4l2_subdev_call(
> -			sd, pad, set_selection, subdev_fh->pad, sel);
> +			sd, pad, set_selection, &subdev_fh->cfg, sel);
>  	}
>  
>  	case VIDIOC_G_EDID: {

So far, it's a pretty simple change :-)

I'd actually take it one step further (on top of course), and store an
instance of v4l2_subdev_config in v4l2_subdev for the active
configuration. This can massively simplify subdev drivers.

> @@ -892,35 +891,35 @@ int v4l2_subdev_link_validate(struct media_link *link)
>  }
>  EXPORT_SYMBOL_GPL(v4l2_subdev_link_validate);
>  
> -struct v4l2_subdev_pad_config *
> -v4l2_subdev_alloc_pad_config(struct v4l2_subdev *sd)
> +int v4l2_subdev_init_config(struct v4l2_subdev *sd, struct v4l2_subdev_config *cfg)

Line wrap (and below too).

>  {
> -	struct v4l2_subdev_pad_config *cfg;
>  	int ret;
>  
> -	if (!sd->entity.num_pads)
> -		return NULL;
> -
> -	cfg = kvmalloc_array(sd->entity.num_pads, sizeof(*cfg),
> -			     GFP_KERNEL | __GFP_ZERO);
> -	if (!cfg)
> -		return NULL;
> +	if (sd->entity.num_pads) {
> +		cfg->pad_configs = kvmalloc_array(sd->entity.num_pads, sizeof(*cfg->pad_configs),
> +				     GFP_KERNEL | __GFP_ZERO);
> +		if (!cfg->pad_configs)
> +			return -ENOMEM;
> +	} else {
> +		cfg->pad_configs = NULL;
> +	}

How about memsetting the whole structure to 0 first ?

>  
>  	ret = v4l2_subdev_call(sd, pad, init_cfg, cfg);
>  	if (ret < 0 && ret != -ENOIOCTLCMD) {
> -		kvfree(cfg);
> -		return NULL;
> +		kvfree(cfg->pad_configs);
> +		return ret;
>  	}
>  
> -	return cfg;
> +	return 0;
>  }
> -EXPORT_SYMBOL_GPL(v4l2_subdev_alloc_pad_config);
> +EXPORT_SYMBOL_GPL(v4l2_subdev_init_config);
>  
> -void v4l2_subdev_free_pad_config(struct v4l2_subdev_pad_config *cfg)
> +void v4l2_subdev_uninit_config(struct v4l2_subdev_config *cfg)
>  {
> -	kvfree(cfg);
> +	kvfree(cfg->pad_configs);
>  }
> -EXPORT_SYMBOL_GPL(v4l2_subdev_free_pad_config);
> +EXPORT_SYMBOL_GPL(v4l2_subdev_uninit_config);
> +
>  #endif /* CONFIG_MEDIA_CONTROLLER */
>  
>  void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index d0e9a5bdb08b..1873e527987a 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -623,6 +623,10 @@ struct v4l2_subdev_pad_config {
>  	struct v4l2_rect try_compose;
>  };
>  
> +struct v4l2_subdev_config {
> +	struct v4l2_subdev_pad_config *pad_configs;

s/pad_configs/pads/ ?

I'm tempted to also store the number of pads here. It would be redundant
as the value is available from the v4l2_subdev structure, but it would
allow operating on v4l2_subdev_config without a subdev pointer. Or,
possibly better, we could store a pointer to the subdev.

I'm also tempted to name the structure v4l2_subdev_state, as that's what
it stores. I may be biased by DRM/KMS, but I don't see a downside in
using identical names for identical concepts.

> +};
> +
>  /**
>   * struct v4l2_subdev_pad_ops - v4l2-subdev pad level operations
>   *
> @@ -687,27 +691,27 @@ struct v4l2_subdev_pad_config {
>   */
>  struct v4l2_subdev_pad_ops {
>  	int (*init_cfg)(struct v4l2_subdev *sd,
> -			struct v4l2_subdev_pad_config *cfg);
> +			struct v4l2_subdev_config *cfg);
>  	int (*enum_mbus_code)(struct v4l2_subdev *sd,
> -			      struct v4l2_subdev_pad_config *cfg,
> +			      struct v4l2_subdev_config *cfg,
>  			      struct v4l2_subdev_mbus_code_enum *code);
>  	int (*enum_frame_size)(struct v4l2_subdev *sd,
> -			       struct v4l2_subdev_pad_config *cfg,
> +			       struct v4l2_subdev_config *cfg,
>  			       struct v4l2_subdev_frame_size_enum *fse);
>  	int (*enum_frame_interval)(struct v4l2_subdev *sd,
> -				   struct v4l2_subdev_pad_config *cfg,
> +				   struct v4l2_subdev_config *cfg,
>  				   struct v4l2_subdev_frame_interval_enum *fie);
>  	int (*get_fmt)(struct v4l2_subdev *sd,
> -		       struct v4l2_subdev_pad_config *cfg,
> +		       struct v4l2_subdev_config *cfg,
>  		       struct v4l2_subdev_format *format);
>  	int (*set_fmt)(struct v4l2_subdev *sd,
> -		       struct v4l2_subdev_pad_config *cfg,
> +		       struct v4l2_subdev_config *cfg,
>  		       struct v4l2_subdev_format *format);
>  	int (*get_selection)(struct v4l2_subdev *sd,
> -			     struct v4l2_subdev_pad_config *cfg,
> +			     struct v4l2_subdev_config *cfg,
>  			     struct v4l2_subdev_selection *sel);
>  	int (*set_selection)(struct v4l2_subdev *sd,
> -			     struct v4l2_subdev_pad_config *cfg,
> +			     struct v4l2_subdev_config *cfg,
>  			     struct v4l2_subdev_selection *sel);
>  	int (*get_edid)(struct v4l2_subdev *sd, struct v4l2_edid *edid);
>  	int (*set_edid)(struct v4l2_subdev *sd, struct v4l2_edid *edid);
> @@ -925,7 +929,7 @@ struct v4l2_subdev_fh {
>  	struct v4l2_fh vfh;
>  	struct module *owner;
>  #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
> -	struct v4l2_subdev_pad_config *pad;
> +	struct v4l2_subdev_config cfg;
>  #endif
>  };
>  
> @@ -950,12 +954,12 @@ struct v4l2_subdev_fh {
>   */
>  static inline struct v4l2_mbus_framefmt *
>  v4l2_subdev_get_try_format(struct v4l2_subdev *sd,
> -			   struct v4l2_subdev_pad_config *cfg,
> +			   struct v4l2_subdev_config *cfg,
>  			   unsigned int pad)
>  {
>  	if (WARN_ON(pad >= sd->entity.num_pads))
>  		pad = 0;
> -	return &cfg[pad].try_fmt;
> +	return &cfg->pad_configs[pad].try_fmt;
>  }
>  
>  /**
> @@ -968,12 +972,12 @@ v4l2_subdev_get_try_format(struct v4l2_subdev *sd,
>   */
>  static inline struct v4l2_rect *
>  v4l2_subdev_get_try_crop(struct v4l2_subdev *sd,
> -			 struct v4l2_subdev_pad_config *cfg,
> +			 struct v4l2_subdev_config *cfg,
>  			 unsigned int pad)
>  {
>  	if (WARN_ON(pad >= sd->entity.num_pads))
>  		pad = 0;
> -	return &cfg[pad].try_crop;
> +	return &cfg->pad_configs[pad].try_crop;
>  }
>  
>  /**
> @@ -986,12 +990,12 @@ v4l2_subdev_get_try_crop(struct v4l2_subdev *sd,
>   */
>  static inline struct v4l2_rect *
>  v4l2_subdev_get_try_compose(struct v4l2_subdev *sd,
> -			    struct v4l2_subdev_pad_config *cfg,
> +			    struct v4l2_subdev_config *cfg,
>  			    unsigned int pad)
>  {
>  	if (WARN_ON(pad >= sd->entity.num_pads))
>  		pad = 0;
> -	return &cfg[pad].try_compose;
> +	return &cfg->pad_configs[pad].try_compose;
>  }
>  
>  #endif
> @@ -1093,20 +1097,17 @@ int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd,
>  int v4l2_subdev_link_validate(struct media_link *link);
>  
>  /**
> - * v4l2_subdev_alloc_pad_config - Allocates memory for pad config
> + * v4l2_subdev_init_config - initialize v4l2_subdev_config
>   *
> - * @sd: pointer to struct v4l2_subdev
> + * Must call v4l2_subdev_uninit_config() when config is no longer needed.
>   */
> -struct
> -v4l2_subdev_pad_config *v4l2_subdev_alloc_pad_config(struct v4l2_subdev *sd);
> +int v4l2_subdev_init_config(struct v4l2_subdev *sd, struct v4l2_subdev_config *cfg);
>  
>  /**
> - * v4l2_subdev_free_pad_config - Frees memory allocated by
> - *	v4l2_subdev_alloc_pad_config().
> - *
> - * @cfg: pointer to &struct v4l2_subdev_pad_config
> + * v4l2_subdev_uninit_config - uninitialize v4l2_subdev_config
>   */
> -void v4l2_subdev_free_pad_config(struct v4l2_subdev_pad_config *cfg);
> +void v4l2_subdev_uninit_config(struct v4l2_subdev_config *cfg);

Finally, still on the naming topic, if you agree with v4l2_subdev_state,
I'd name the function v4l2_subdev_state_init() and
v4l2_subdev_state_cleanup(). I have a feeling we may be better off
allocating states dynamically (storing a pointer in v4l2_subdev_fh
instead of embedding an instance), in which case
v4l2_subdev_state_alloc() and v4l2_subdev_state_free() would be better,
but that's just a feeling at this point.

> +
>  #endif /* CONFIG_MEDIA_CONTROLLER */
>  
>  /**

-- 
Regards,

Laurent Pinchart

Re: [PATCH] RFC: media: v4l2-subdev: add subdev-wide config struct

[Hans Verkuil]

On 18/04/2021 18:07, Laurent Pinchart wrote:
> Hi Tomi,
> 
> Thank you for the patch.
> 
> Hans, Sakari, could you share your opinion on this ? I see lots of
> potential in this proposal (both for bikeshedding, and for actual
> value). We need an ack on the concept, and likely naming scheme too,
> before developing a final patch, as it's lots of churn in lots of
> drivers.
> 
> On Fri, Apr 09, 2021 at 04:36:59PM +0300, Tomi Valkeinen wrote:
>> We have 'struct v4l2_subdev_pad_config' which contains configuration for
>> a single pad used for the TRY functionality, and an array of those
>> structs is passed to various v4l2_subdev_pad_ops.
>>
>> I was working on subdev internal routing between pads, and realized that
>> there's no way to add TRY functionality for routes, which is not pad
>> specific configuration. Adding a separate struct for try-route config
>> wouldn't work either, as e.g. set-fmt needs to know the try-route
>> configuration to propagate the settings.
>>
>> This patch adds a new struct, 'struct v4l2_subdev_config' (which at the
>> moment only contains the v4l2_subdev_pad_config array) and the new
>> struct is used in most of the places where v4l2_subdev_pad_config was
>> used. All v4l2_subdev_pad_ops functions taking v4l2_subdev_pad_config
>> are changed to instead take v4l2_subdev_config.
>>
>> Two drivers are changed to work with the above changes (drivers for HW
>> which I have) as an example.
>>
>> I worked on a semantic patch (included below, my first spatch...) to do
>> this change to all drivers, but hit lots of problems with non-trivial
>> uses of v4l2_subdev_pad_config.
>>
>> As it looks like substantial amount of manual work is needed, I'm
>> posting this RFC to get an ack on the changes before continuing that
>> work.
>>
>> @ v4l2_subdev_pad_ops @
>> identifier pad_ops;
>> identifier func;
>> @@
>>
>> (
>> static const struct v4l2_subdev_pad_ops pad_ops = {
>>         ...,
>>         .enum_mbus_code = func,
>>         ...,
>> };
>> |
>> static const struct v4l2_subdev_pad_ops pad_ops = {
>>         ...,
>>         .enum_frame_size = func,
>>         ...,
>> };
>> |
>> static const struct v4l2_subdev_pad_ops pad_ops = {
>>         ...,
>>         .enum_frame_interval = func,
>>         ...,
>> };
>> |
>> static const struct v4l2_subdev_pad_ops pad_ops = {
>>         ...,
>>         .get_fmt = func,
>>         ...,
>> };
>> |
>> static const struct v4l2_subdev_pad_ops pad_ops = {
>>         ...,
>>         .set_fmt = func,
>>         ...,
>> };
>> |
>> static const struct v4l2_subdev_pad_ops pad_ops = {
>>         ...,
>>         .get_selection = func,
>>         ...,
>> };
>> |
>> static const struct v4l2_subdev_pad_ops pad_ops = {
>>         ...,
>>         .set_selection = func,
>>         ...,
>> };
>> |
>> static const struct v4l2_subdev_pad_ops pad_ops = {
>>         ...,
>>         .init_cfg = func,
>>         ...,
>> };
>> )
>>
>> @@
>> identifier v4l2_subdev_pad_ops.func;
>> identifier sd;
>> identifier cfg;
>> @@
>>
>>  func(struct v4l2_subdev *sd,
>> -	struct v4l2_subdev_pad_config *cfg,
>> +	struct v4l2_subdev_config *cfg,
>> 	...
>>       )
>>  {
>>     ...
>>  }
>>
>> @@
>> identifier v4l2_subdev_pad_ops.func;
>> identifier sd;
>> identifier cfg;
>> @@
>>
>>  func(struct v4l2_subdev *sd,
>> -   struct v4l2_subdev_pad_config *cfg
>> +   struct v4l2_subdev_config *cfg
>>       )
>>  {
>>     ...
>>  }
>>
>> @@
>> struct v4l2_subdev_fh *fh;
>> @@
>> -    fh->pad
>> +    &fh->cfg
>>
>> @@
>> identifier func;
>> identifier cfg;
>> @@
>>
>> func(...,
>> - struct v4l2_subdev_pad_config *cfg,
>> + struct v4l2_subdev_config *cfg,
>>  ...)
>> {
>>     ...
>> }
>>
>> @@
>> struct v4l2_subdev_config *cfg;
>> @@
>>  {
>>     <...
>> (
>> -   cfg->try_fmt
>> +   cfg->pad_configs->try_fmt
>> |
>> -   cfg->try_crop
>> +   cfg->pad_configs->try_crop
>> |
>> -   cfg->try_compose
>> +   cfg->pad_configs->try_compose
>> )
>>     ...>
>>  }
>>
>> @@
>> identifier pad_cfg;
>> @@
>> {
>>     ...
>>     struct v4l2_subdev_pad_config pad_cfg;
>> +   struct v4l2_subdev_config cfg = { .pad_configs = &pad_cfg };
>>     <...
>> -   &pad_cfg
>> +   &cfg
>>     ...>
>> }
>>
> 
> This doesn't look too bad (although the last change seems a bit weird),
> but I suppose it's not the whole story, as you've mentioned above.
> 
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> ---
>>  drivers/media/i2c/ov5640.c                   | 10 +--
>>  drivers/media/platform/ti-vpe/cal-camerarx.c | 12 +--
>>  drivers/media/v4l2-core/v4l2-subdev.c        | 85 ++++++++++----------
>>  include/media/v4l2-subdev.h                  | 49 +++++------
>>  4 files changed, 78 insertions(+), 78 deletions(-)
>>
>> diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
>> index 14f3afa7721a..7c76c0754426 100644
>> --- a/drivers/media/i2c/ov5640.c
>> +++ b/drivers/media/i2c/ov5640.c
>> @@ -2227,7 +2227,7 @@ static int ov5640_try_frame_interval(struct ov5640_dev *sensor,
>>  }
>>  
>>  static int ov5640_get_fmt(struct v4l2_subdev *sd,
>> -			  struct v4l2_subdev_pad_config *cfg,
>> +			  struct v4l2_subdev_config *cfg,
>>  			  struct v4l2_subdev_format *format)
>>  {
>>  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
>> @@ -2285,7 +2285,7 @@ static int ov5640_try_fmt_internal(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int ov5640_set_fmt(struct v4l2_subdev *sd,
>> -			  struct v4l2_subdev_pad_config *cfg,
>> +			  struct v4l2_subdev_config *cfg,
>>  			  struct v4l2_subdev_format *format)
>>  {
>>  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
>> @@ -2818,7 +2818,7 @@ static int ov5640_init_controls(struct ov5640_dev *sensor)
>>  }
>>  
>>  static int ov5640_enum_frame_size(struct v4l2_subdev *sd,
>> -				  struct v4l2_subdev_pad_config *cfg,
>> +				  struct v4l2_subdev_config *cfg,
>>  				  struct v4l2_subdev_frame_size_enum *fse)
>>  {
>>  	if (fse->pad != 0)
>> @@ -2838,7 +2838,7 @@ static int ov5640_enum_frame_size(struct v4l2_subdev *sd,
>>  
>>  static int ov5640_enum_frame_interval(
>>  	struct v4l2_subdev *sd,
>> -	struct v4l2_subdev_pad_config *cfg,
>> +	struct v4l2_subdev_config *cfg,
>>  	struct v4l2_subdev_frame_interval_enum *fie)
>>  {
>>  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
>> @@ -2924,7 +2924,7 @@ static int ov5640_s_frame_interval(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int ov5640_enum_mbus_code(struct v4l2_subdev *sd,
>> -				 struct v4l2_subdev_pad_config *cfg,
>> +				 struct v4l2_subdev_config *cfg,
>>  				 struct v4l2_subdev_mbus_code_enum *code)
>>  {
>>  	if (code->pad != 0)
>> diff --git a/drivers/media/platform/ti-vpe/cal-camerarx.c b/drivers/media/platform/ti-vpe/cal-camerarx.c
>> index cbe6114908de..c708c61f2188 100644
>> --- a/drivers/media/platform/ti-vpe/cal-camerarx.c
>> +++ b/drivers/media/platform/ti-vpe/cal-camerarx.c
>> @@ -586,7 +586,7 @@ static inline struct cal_camerarx *to_cal_camerarx(struct v4l2_subdev *sd)
>>  
>>  static struct v4l2_mbus_framefmt *
>>  cal_camerarx_get_pad_format(struct cal_camerarx *phy,
>> -			    struct v4l2_subdev_pad_config *cfg,
>> +			    struct v4l2_subdev_config *cfg,
>>  			    unsigned int pad, u32 which)
>>  {
>>  	switch (which) {
>> @@ -611,7 +611,7 @@ static int cal_camerarx_sd_s_stream(struct v4l2_subdev *sd, int enable)
>>  }
>>  
>>  static int cal_camerarx_sd_enum_mbus_code(struct v4l2_subdev *sd,
>> -					  struct v4l2_subdev_pad_config *cfg,
>> +					  struct v4l2_subdev_config *cfg,
>>  					  struct v4l2_subdev_mbus_code_enum *code)
>>  {
>>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
>> @@ -639,7 +639,7 @@ static int cal_camerarx_sd_enum_mbus_code(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,
>> -					   struct v4l2_subdev_pad_config *cfg,
>> +					   struct v4l2_subdev_config *cfg,
>>  					   struct v4l2_subdev_frame_size_enum *fse)
>>  {
>>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
>> @@ -679,7 +679,7 @@ static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,
>> -				   struct v4l2_subdev_pad_config *cfg,
>> +				   struct v4l2_subdev_config *cfg,
>>  				   struct v4l2_subdev_format *format)
>>  {
>>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
>> @@ -692,7 +692,7 @@ static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
>> -				   struct v4l2_subdev_pad_config *cfg,
>> +				   struct v4l2_subdev_config *cfg,
>>  				   struct v4l2_subdev_format *format)
>>  {
>>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
>> @@ -742,7 +742,7 @@ static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int cal_camerarx_sd_init_cfg(struct v4l2_subdev *sd,
>> -				    struct v4l2_subdev_pad_config *cfg)
>> +				    struct v4l2_subdev_config *cfg)
>>  {
>>  	struct v4l2_subdev_format format = {
>>  		.which = cfg ? V4L2_SUBDEV_FORMAT_TRY
>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
>> index 956dafab43d4..248fa4ee9356 100644
>> --- a/drivers/media/v4l2-core/v4l2-subdev.c
>> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
>> @@ -26,19 +26,18 @@
>>  #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
>>  static int subdev_fh_init(struct v4l2_subdev_fh *fh, struct v4l2_subdev *sd)
>>  {
>> -	if (sd->entity.num_pads) {
>> -		fh->pad = v4l2_subdev_alloc_pad_config(sd);
>> -		if (fh->pad == NULL)
>> -			return -ENOMEM;
>> -	}
>> +	int ret;
>> +
>> +	ret = v4l2_subdev_init_config(sd, &fh->cfg);
>> +	if (ret)
>> +		return ret;
>>  
>>  	return 0;
>>  }
>>  
>>  static void subdev_fh_free(struct v4l2_subdev_fh *fh)
>>  {
>> -	v4l2_subdev_free_pad_config(fh->pad);
>> -	fh->pad = NULL;
>> +	v4l2_subdev_uninit_config(&fh->cfg);
>>  }
>>  
>>  static int subdev_open(struct file *file)
>> @@ -146,7 +145,7 @@ static inline int check_pad(struct v4l2_subdev *sd, u32 pad)
>>  	return 0;
>>  }
>>  
>> -static int check_cfg(u32 which, struct v4l2_subdev_pad_config *cfg)
>> +static int check_cfg(u32 which, struct v4l2_subdev_config *cfg)
>>  {
>>  	if (which == V4L2_SUBDEV_FORMAT_TRY && !cfg)
>>  		return -EINVAL;
>> @@ -155,7 +154,7 @@ static int check_cfg(u32 which, struct v4l2_subdev_pad_config *cfg)
>>  }
>>  
>>  static inline int check_format(struct v4l2_subdev *sd,
>> -			       struct v4l2_subdev_pad_config *cfg,
>> +			       struct v4l2_subdev_config *cfg,
>>  			       struct v4l2_subdev_format *format)
>>  {
>>  	if (!format)
>> @@ -166,7 +165,7 @@ static inline int check_format(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int call_get_fmt(struct v4l2_subdev *sd,
>> -			struct v4l2_subdev_pad_config *cfg,
>> +			struct v4l2_subdev_config *cfg,
>>  			struct v4l2_subdev_format *format)
>>  {
>>  	return check_format(sd, cfg, format) ? :
>> @@ -174,7 +173,7 @@ static int call_get_fmt(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int call_set_fmt(struct v4l2_subdev *sd,
>> -			struct v4l2_subdev_pad_config *cfg,
>> +			struct v4l2_subdev_config *cfg,
>>  			struct v4l2_subdev_format *format)
>>  {
>>  	return check_format(sd, cfg, format) ? :
>> @@ -182,7 +181,7 @@ static int call_set_fmt(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int call_enum_mbus_code(struct v4l2_subdev *sd,
>> -			       struct v4l2_subdev_pad_config *cfg,
>> +			       struct v4l2_subdev_config *cfg,
>>  			       struct v4l2_subdev_mbus_code_enum *code)
>>  {
>>  	if (!code)
>> @@ -194,7 +193,7 @@ static int call_enum_mbus_code(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int call_enum_frame_size(struct v4l2_subdev *sd,
>> -				struct v4l2_subdev_pad_config *cfg,
>> +				struct v4l2_subdev_config *cfg,
>>  				struct v4l2_subdev_frame_size_enum *fse)
>>  {
>>  	if (!fse)
>> @@ -229,7 +228,7 @@ static int call_s_frame_interval(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int call_enum_frame_interval(struct v4l2_subdev *sd,
>> -				    struct v4l2_subdev_pad_config *cfg,
>> +				    struct v4l2_subdev_config *cfg,
>>  				    struct v4l2_subdev_frame_interval_enum *fie)
>>  {
>>  	if (!fie)
>> @@ -241,7 +240,7 @@ static int call_enum_frame_interval(struct v4l2_subdev *sd,
>>  }
>>  
>>  static inline int check_selection(struct v4l2_subdev *sd,
>> -				  struct v4l2_subdev_pad_config *cfg,
>> +				  struct v4l2_subdev_config *cfg,
>>  				  struct v4l2_subdev_selection *sel)
>>  {
>>  	if (!sel)
>> @@ -252,7 +251,7 @@ static inline int check_selection(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int call_get_selection(struct v4l2_subdev *sd,
>> -			      struct v4l2_subdev_pad_config *cfg,
>> +			      struct v4l2_subdev_config *cfg,
>>  			      struct v4l2_subdev_selection *sel)
>>  {
>>  	return check_selection(sd, cfg, sel) ? :
>> @@ -260,7 +259,7 @@ static int call_get_selection(struct v4l2_subdev *sd,
>>  }
>>  
>>  static int call_set_selection(struct v4l2_subdev *sd,
>> -			      struct v4l2_subdev_pad_config *cfg,
>> +			      struct v4l2_subdev_config *cfg,
>>  			      struct v4l2_subdev_selection *sel)
>>  {
>>  	return check_selection(sd, cfg, sel) ? :
>> @@ -506,7 +505,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>  
>>  		memset(format->reserved, 0, sizeof(format->reserved));
>>  		memset(format->format.reserved, 0, sizeof(format->format.reserved));
>> -		return v4l2_subdev_call(sd, pad, get_fmt, subdev_fh->pad, format);
>> +		return v4l2_subdev_call(sd, pad, get_fmt, &subdev_fh->cfg, format);
>>  	}
>>  
>>  	case VIDIOC_SUBDEV_S_FMT: {
>> @@ -517,7 +516,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>  
>>  		memset(format->reserved, 0, sizeof(format->reserved));
>>  		memset(format->format.reserved, 0, sizeof(format->format.reserved));
>> -		return v4l2_subdev_call(sd, pad, set_fmt, subdev_fh->pad, format);
>> +		return v4l2_subdev_call(sd, pad, set_fmt, &subdev_fh->cfg, format);
>>  	}
>>  
>>  	case VIDIOC_SUBDEV_G_CROP: {
>> @@ -531,7 +530,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>  		sel.target = V4L2_SEL_TGT_CROP;
>>  
>>  		rval = v4l2_subdev_call(
>> -			sd, pad, get_selection, subdev_fh->pad, &sel);
>> +			sd, pad, get_selection, &subdev_fh->cfg, &sel);
>>  
>>  		crop->rect = sel.r;
>>  
>> @@ -553,7 +552,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>  		sel.r = crop->rect;
>>  
>>  		rval = v4l2_subdev_call(
>> -			sd, pad, set_selection, subdev_fh->pad, &sel);
>> +			sd, pad, set_selection, &subdev_fh->cfg, &sel);
>>  
>>  		crop->rect = sel.r;
>>  
>> @@ -564,7 +563,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>  		struct v4l2_subdev_mbus_code_enum *code = arg;
>>  
>>  		memset(code->reserved, 0, sizeof(code->reserved));
>> -		return v4l2_subdev_call(sd, pad, enum_mbus_code, subdev_fh->pad,
>> +		return v4l2_subdev_call(sd, pad, enum_mbus_code, &subdev_fh->cfg,
>>  					code);
>>  	}
>>  
>> @@ -572,7 +571,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>  		struct v4l2_subdev_frame_size_enum *fse = arg;
>>  
>>  		memset(fse->reserved, 0, sizeof(fse->reserved));
>> -		return v4l2_subdev_call(sd, pad, enum_frame_size, subdev_fh->pad,
>> +		return v4l2_subdev_call(sd, pad, enum_frame_size, &subdev_fh->cfg,
>>  					fse);
>>  	}
>>  
>> @@ -597,7 +596,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>  		struct v4l2_subdev_frame_interval_enum *fie = arg;
>>  
>>  		memset(fie->reserved, 0, sizeof(fie->reserved));
>> -		return v4l2_subdev_call(sd, pad, enum_frame_interval, subdev_fh->pad,
>> +		return v4l2_subdev_call(sd, pad, enum_frame_interval, &subdev_fh->cfg,
>>  					fie);
>>  	}
>>  
>> @@ -606,7 +605,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>  
>>  		memset(sel->reserved, 0, sizeof(sel->reserved));
>>  		return v4l2_subdev_call(
>> -			sd, pad, get_selection, subdev_fh->pad, sel);
>> +			sd, pad, get_selection, &subdev_fh->cfg, sel);
>>  	}
>>  
>>  	case VIDIOC_SUBDEV_S_SELECTION: {
>> @@ -617,7 +616,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>  
>>  		memset(sel->reserved, 0, sizeof(sel->reserved));
>>  		return v4l2_subdev_call(
>> -			sd, pad, set_selection, subdev_fh->pad, sel);
>> +			sd, pad, set_selection, &subdev_fh->cfg, sel);
>>  	}
>>  
>>  	case VIDIOC_G_EDID: {
> 
> So far, it's a pretty simple change :-)
> 
> I'd actually take it one step further (on top of course), and store an
> instance of v4l2_subdev_config in v4l2_subdev for the active
> configuration. This can massively simplify subdev drivers.

Hmm, struct v4l2_subdev_pad_config talks about try_fmt/crop/compose, that
would be weird for the active configuration.

I guess you would have to experiment a bit with this.

> 
>> @@ -892,35 +891,35 @@ int v4l2_subdev_link_validate(struct media_link *link)
>>  }
>>  EXPORT_SYMBOL_GPL(v4l2_subdev_link_validate);
>>  
>> -struct v4l2_subdev_pad_config *
>> -v4l2_subdev_alloc_pad_config(struct v4l2_subdev *sd)
>> +int v4l2_subdev_init_config(struct v4l2_subdev *sd, struct v4l2_subdev_config *cfg)
> 
> Line wrap (and below too).
> 
>>  {
>> -	struct v4l2_subdev_pad_config *cfg;
>>  	int ret;
>>  
>> -	if (!sd->entity.num_pads)
>> -		return NULL;
>> -
>> -	cfg = kvmalloc_array(sd->entity.num_pads, sizeof(*cfg),
>> -			     GFP_KERNEL | __GFP_ZERO);
>> -	if (!cfg)
>> -		return NULL;
>> +	if (sd->entity.num_pads) {
>> +		cfg->pad_configs = kvmalloc_array(sd->entity.num_pads, sizeof(*cfg->pad_configs),
>> +				     GFP_KERNEL | __GFP_ZERO);
>> +		if (!cfg->pad_configs)
>> +			return -ENOMEM;
>> +	} else {
>> +		cfg->pad_configs = NULL;
>> +	}
> 
> How about memsetting the whole structure to 0 first ?
> 
>>  
>>  	ret = v4l2_subdev_call(sd, pad, init_cfg, cfg);
>>  	if (ret < 0 && ret != -ENOIOCTLCMD) {
>> -		kvfree(cfg);
>> -		return NULL;
>> +		kvfree(cfg->pad_configs);
>> +		return ret;
>>  	}
>>  
>> -	return cfg;
>> +	return 0;
>>  }
>> -EXPORT_SYMBOL_GPL(v4l2_subdev_alloc_pad_config);
>> +EXPORT_SYMBOL_GPL(v4l2_subdev_init_config);
>>  
>> -void v4l2_subdev_free_pad_config(struct v4l2_subdev_pad_config *cfg)
>> +void v4l2_subdev_uninit_config(struct v4l2_subdev_config *cfg)
>>  {
>> -	kvfree(cfg);
>> +	kvfree(cfg->pad_configs);
>>  }
>> -EXPORT_SYMBOL_GPL(v4l2_subdev_free_pad_config);
>> +EXPORT_SYMBOL_GPL(v4l2_subdev_uninit_config);
>> +
>>  #endif /* CONFIG_MEDIA_CONTROLLER */
>>  
>>  void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
>> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
>> index d0e9a5bdb08b..1873e527987a 100644
>> --- a/include/media/v4l2-subdev.h
>> +++ b/include/media/v4l2-subdev.h
>> @@ -623,6 +623,10 @@ struct v4l2_subdev_pad_config {
>>  	struct v4l2_rect try_compose;
>>  };
>>  
>> +struct v4l2_subdev_config {
>> +	struct v4l2_subdev_pad_config *pad_configs;
> 
> s/pad_configs/pads/ ?

I agree.

> 
> I'm tempted to also store the number of pads here. It would be redundant
> as the value is available from the v4l2_subdev structure, but it would
> allow operating on v4l2_subdev_config without a subdev pointer. Or,
> possibly better, we could store a pointer to the subdev.
> 
> I'm also tempted to name the structure v4l2_subdev_state, as that's what
> it stores. I may be biased by DRM/KMS, but I don't see a downside in
> using identical names for identical concepts.

I like v4l2_subdev_state better than v4l2_subdev_config, so I would be OK
with such a change.

> 
>> +};
>> +
>>  /**
>>   * struct v4l2_subdev_pad_ops - v4l2-subdev pad level operations
>>   *
>> @@ -687,27 +691,27 @@ struct v4l2_subdev_pad_config {
>>   */
>>  struct v4l2_subdev_pad_ops {
>>  	int (*init_cfg)(struct v4l2_subdev *sd,

If we do change the name, then this probably should be renamed to init_state as well.

>> -			struct v4l2_subdev_pad_config *cfg);
>> +			struct v4l2_subdev_config *cfg);
>>  	int (*enum_mbus_code)(struct v4l2_subdev *sd,
>> -			      struct v4l2_subdev_pad_config *cfg,
>> +			      struct v4l2_subdev_config *cfg,
>>  			      struct v4l2_subdev_mbus_code_enum *code);
>>  	int (*enum_frame_size)(struct v4l2_subdev *sd,
>> -			       struct v4l2_subdev_pad_config *cfg,
>> +			       struct v4l2_subdev_config *cfg,
>>  			       struct v4l2_subdev_frame_size_enum *fse);
>>  	int (*enum_frame_interval)(struct v4l2_subdev *sd,
>> -				   struct v4l2_subdev_pad_config *cfg,
>> +				   struct v4l2_subdev_config *cfg,
>>  				   struct v4l2_subdev_frame_interval_enum *fie);
>>  	int (*get_fmt)(struct v4l2_subdev *sd,
>> -		       struct v4l2_subdev_pad_config *cfg,
>> +		       struct v4l2_subdev_config *cfg,
>>  		       struct v4l2_subdev_format *format);
>>  	int (*set_fmt)(struct v4l2_subdev *sd,
>> -		       struct v4l2_subdev_pad_config *cfg,
>> +		       struct v4l2_subdev_config *cfg,
>>  		       struct v4l2_subdev_format *format);
>>  	int (*get_selection)(struct v4l2_subdev *sd,
>> -			     struct v4l2_subdev_pad_config *cfg,
>> +			     struct v4l2_subdev_config *cfg,
>>  			     struct v4l2_subdev_selection *sel);
>>  	int (*set_selection)(struct v4l2_subdev *sd,
>> -			     struct v4l2_subdev_pad_config *cfg,
>> +			     struct v4l2_subdev_config *cfg,
>>  			     struct v4l2_subdev_selection *sel);
>>  	int (*get_edid)(struct v4l2_subdev *sd, struct v4l2_edid *edid);
>>  	int (*set_edid)(struct v4l2_subdev *sd, struct v4l2_edid *edid);
>> @@ -925,7 +929,7 @@ struct v4l2_subdev_fh {
>>  	struct v4l2_fh vfh;
>>  	struct module *owner;
>>  #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
>> -	struct v4l2_subdev_pad_config *pad;
>> +	struct v4l2_subdev_config cfg;

And of course cfg becomes 'state' too.

>>  #endif
>>  };
>>  
>> @@ -950,12 +954,12 @@ struct v4l2_subdev_fh {
>>   */
>>  static inline struct v4l2_mbus_framefmt *
>>  v4l2_subdev_get_try_format(struct v4l2_subdev *sd,
>> -			   struct v4l2_subdev_pad_config *cfg,
>> +			   struct v4l2_subdev_config *cfg,
>>  			   unsigned int pad)
>>  {
>>  	if (WARN_ON(pad >= sd->entity.num_pads))
>>  		pad = 0;
>> -	return &cfg[pad].try_fmt;
>> +	return &cfg->pad_configs[pad].try_fmt;
>>  }
>>  
>>  /**
>> @@ -968,12 +972,12 @@ v4l2_subdev_get_try_format(struct v4l2_subdev *sd,
>>   */
>>  static inline struct v4l2_rect *
>>  v4l2_subdev_get_try_crop(struct v4l2_subdev *sd,
>> -			 struct v4l2_subdev_pad_config *cfg,
>> +			 struct v4l2_subdev_config *cfg,
>>  			 unsigned int pad)
>>  {
>>  	if (WARN_ON(pad >= sd->entity.num_pads))
>>  		pad = 0;
>> -	return &cfg[pad].try_crop;
>> +	return &cfg->pad_configs[pad].try_crop;
>>  }
>>  
>>  /**
>> @@ -986,12 +990,12 @@ v4l2_subdev_get_try_crop(struct v4l2_subdev *sd,
>>   */
>>  static inline struct v4l2_rect *
>>  v4l2_subdev_get_try_compose(struct v4l2_subdev *sd,
>> -			    struct v4l2_subdev_pad_config *cfg,
>> +			    struct v4l2_subdev_config *cfg,
>>  			    unsigned int pad)
>>  {
>>  	if (WARN_ON(pad >= sd->entity.num_pads))
>>  		pad = 0;
>> -	return &cfg[pad].try_compose;
>> +	return &cfg->pad_configs[pad].try_compose;
>>  }
>>  
>>  #endif
>> @@ -1093,20 +1097,17 @@ int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd,
>>  int v4l2_subdev_link_validate(struct media_link *link);
>>  
>>  /**
>> - * v4l2_subdev_alloc_pad_config - Allocates memory for pad config
>> + * v4l2_subdev_init_config - initialize v4l2_subdev_config
>>   *
>> - * @sd: pointer to struct v4l2_subdev
>> + * Must call v4l2_subdev_uninit_config() when config is no longer needed.
>>   */
>> -struct
>> -v4l2_subdev_pad_config *v4l2_subdev_alloc_pad_config(struct v4l2_subdev *sd);
>> +int v4l2_subdev_init_config(struct v4l2_subdev *sd, struct v4l2_subdev_config *cfg);
>>  
>>  /**
>> - * v4l2_subdev_free_pad_config - Frees memory allocated by
>> - *	v4l2_subdev_alloc_pad_config().
>> - *
>> - * @cfg: pointer to &struct v4l2_subdev_pad_config
>> + * v4l2_subdev_uninit_config - uninitialize v4l2_subdev_config
>>   */
>> -void v4l2_subdev_free_pad_config(struct v4l2_subdev_pad_config *cfg);
>> +void v4l2_subdev_uninit_config(struct v4l2_subdev_config *cfg);
> 
> Finally, still on the naming topic, if you agree with v4l2_subdev_state,
> I'd name the function v4l2_subdev_state_init() and
> v4l2_subdev_state_cleanup(). I have a feeling we may be better off
> allocating states dynamically (storing a pointer in v4l2_subdev_fh
> instead of embedding an instance), in which case
> v4l2_subdev_state_alloc() and v4l2_subdev_state_free() would be better,
> but that's just a feeling at this point.
> 
>> +
>>  #endif /* CONFIG_MEDIA_CONTROLLER */
>>  
>>  /**
> 

Regards,

	Hans

Re: [PATCH] RFC: media: v4l2-subdev: add subdev-wide config struct

[Sakari Ailus]

Moi,

Thanks for the patch.

On Fri, Apr 09, 2021 at 04:36:59PM +0300, Tomi Valkeinen wrote:
> We have 'struct v4l2_subdev_pad_config' which contains configuration for
> a single pad used for the TRY functionality, and an array of those
> structs is passed to various v4l2_subdev_pad_ops.
> 
> I was working on subdev internal routing between pads, and realized that
> there's no way to add TRY functionality for routes, which is not pad
> specific configuration. Adding a separate struct for try-route config
> wouldn't work either, as e.g. set-fmt needs to know the try-route
> configuration to propagate the settings.
> 
> This patch adds a new struct, 'struct v4l2_subdev_config' (which at the
> moment only contains the v4l2_subdev_pad_config array) and the new
> struct is used in most of the places where v4l2_subdev_pad_config was
> used. All v4l2_subdev_pad_ops functions taking v4l2_subdev_pad_config
> are changed to instead take v4l2_subdev_config.
> 
> Two drivers are changed to work with the above changes (drivers for HW
> which I have) as an example.
> 
> I worked on a semantic patch (included below, my first spatch...) to do
> this change to all drivers, but hit lots of problems with non-trivial
> uses of v4l2_subdev_pad_config.
> 
> As it looks like substantial amount of manual work is needed, I'm
> posting this RFC to get an ack on the changes before continuing that
> work.

Previously the try configuration has been just about pads, and routing
isn't specific to them now.

I think this change makes sense.

Please see my comments below.

> 
> @ v4l2_subdev_pad_ops @
> identifier pad_ops;
> identifier func;
> @@
> 
> (
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .enum_mbus_code = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .enum_frame_size = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .enum_frame_interval = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .get_fmt = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .set_fmt = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .get_selection = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .set_selection = func,
>         ...,
> };
> |
> static const struct v4l2_subdev_pad_ops pad_ops = {
>         ...,
>         .init_cfg = func,
>         ...,
> };
> )
> 
> @@
> identifier v4l2_subdev_pad_ops.func;
> identifier sd;
> identifier cfg;
> @@
> 
>  func(struct v4l2_subdev *sd,
> -	struct v4l2_subdev_pad_config *cfg,
> +	struct v4l2_subdev_config *cfg,
> 	...
>       )
>  {
>     ...
>  }
> 
> @@
> identifier v4l2_subdev_pad_ops.func;
> identifier sd;
> identifier cfg;
> @@
> 
>  func(struct v4l2_subdev *sd,
> -   struct v4l2_subdev_pad_config *cfg
> +   struct v4l2_subdev_config *cfg
>       )
>  {
>     ...
>  }
> 
> @@
> struct v4l2_subdev_fh *fh;
> @@
> -    fh->pad
> +    &fh->cfg
> 
> @@
> identifier func;
> identifier cfg;
> @@
> 
> func(...,
> - struct v4l2_subdev_pad_config *cfg,
> + struct v4l2_subdev_config *cfg,
>  ...)
> {
>     ...
> }
> 
> @@
> struct v4l2_subdev_config *cfg;
> @@
>  {
>     <...
> (
> -   cfg->try_fmt
> +   cfg->pad_configs->try_fmt
> |
> -   cfg->try_crop
> +   cfg->pad_configs->try_crop
> |
> -   cfg->try_compose
> +   cfg->pad_configs->try_compose
> )
>     ...>
>  }
> 
> @@
> identifier pad_cfg;
> @@
> {
>     ...
>     struct v4l2_subdev_pad_config pad_cfg;
> +   struct v4l2_subdev_config cfg = { .pad_configs = &pad_cfg };
>     <...
> -   &pad_cfg
> +   &cfg
>     ...>
> }
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  drivers/media/i2c/ov5640.c                   | 10 +--
>  drivers/media/platform/ti-vpe/cal-camerarx.c | 12 +--
>  drivers/media/v4l2-core/v4l2-subdev.c        | 85 ++++++++++----------
>  include/media/v4l2-subdev.h                  | 49 +++++------
>  4 files changed, 78 insertions(+), 78 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
> index 14f3afa7721a..7c76c0754426 100644
> --- a/drivers/media/i2c/ov5640.c
> +++ b/drivers/media/i2c/ov5640.c
> @@ -2227,7 +2227,7 @@ static int ov5640_try_frame_interval(struct ov5640_dev *sensor,
>  }
>  
>  static int ov5640_get_fmt(struct v4l2_subdev *sd,
> -			  struct v4l2_subdev_pad_config *cfg,
> +			  struct v4l2_subdev_config *cfg,
>  			  struct v4l2_subdev_format *format)
>  {
>  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> @@ -2285,7 +2285,7 @@ static int ov5640_try_fmt_internal(struct v4l2_subdev *sd,
>  }
>  
>  static int ov5640_set_fmt(struct v4l2_subdev *sd,
> -			  struct v4l2_subdev_pad_config *cfg,
> +			  struct v4l2_subdev_config *cfg,
>  			  struct v4l2_subdev_format *format)
>  {
>  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> @@ -2818,7 +2818,7 @@ static int ov5640_init_controls(struct ov5640_dev *sensor)
>  }
>  
>  static int ov5640_enum_frame_size(struct v4l2_subdev *sd,
> -				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_config *cfg,
>  				  struct v4l2_subdev_frame_size_enum *fse)
>  {
>  	if (fse->pad != 0)
> @@ -2838,7 +2838,7 @@ static int ov5640_enum_frame_size(struct v4l2_subdev *sd,
>  
>  static int ov5640_enum_frame_interval(
>  	struct v4l2_subdev *sd,
> -	struct v4l2_subdev_pad_config *cfg,
> +	struct v4l2_subdev_config *cfg,
>  	struct v4l2_subdev_frame_interval_enum *fie)
>  {
>  	struct ov5640_dev *sensor = to_ov5640_dev(sd);
> @@ -2924,7 +2924,7 @@ static int ov5640_s_frame_interval(struct v4l2_subdev *sd,
>  }
>  
>  static int ov5640_enum_mbus_code(struct v4l2_subdev *sd,
> -				 struct v4l2_subdev_pad_config *cfg,
> +				 struct v4l2_subdev_config *cfg,
>  				 struct v4l2_subdev_mbus_code_enum *code)
>  {
>  	if (code->pad != 0)
> diff --git a/drivers/media/platform/ti-vpe/cal-camerarx.c b/drivers/media/platform/ti-vpe/cal-camerarx.c
> index cbe6114908de..c708c61f2188 100644
> --- a/drivers/media/platform/ti-vpe/cal-camerarx.c
> +++ b/drivers/media/platform/ti-vpe/cal-camerarx.c
> @@ -586,7 +586,7 @@ static inline struct cal_camerarx *to_cal_camerarx(struct v4l2_subdev *sd)
>  
>  static struct v4l2_mbus_framefmt *
>  cal_camerarx_get_pad_format(struct cal_camerarx *phy,
> -			    struct v4l2_subdev_pad_config *cfg,
> +			    struct v4l2_subdev_config *cfg,
>  			    unsigned int pad, u32 which)
>  {
>  	switch (which) {
> @@ -611,7 +611,7 @@ static int cal_camerarx_sd_s_stream(struct v4l2_subdev *sd, int enable)
>  }
>  
>  static int cal_camerarx_sd_enum_mbus_code(struct v4l2_subdev *sd,
> -					  struct v4l2_subdev_pad_config *cfg,
> +					  struct v4l2_subdev_config *cfg,
>  					  struct v4l2_subdev_mbus_code_enum *code)
>  {
>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
> @@ -639,7 +639,7 @@ static int cal_camerarx_sd_enum_mbus_code(struct v4l2_subdev *sd,
>  }
>  
>  static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,
> -					   struct v4l2_subdev_pad_config *cfg,
> +					   struct v4l2_subdev_config *cfg,
>  					   struct v4l2_subdev_frame_size_enum *fse)
>  {
>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
> @@ -679,7 +679,7 @@ static int cal_camerarx_sd_enum_frame_size(struct v4l2_subdev *sd,
>  }
>  
>  static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,
> -				   struct v4l2_subdev_pad_config *cfg,
> +				   struct v4l2_subdev_config *cfg,
>  				   struct v4l2_subdev_format *format)
>  {
>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
> @@ -692,7 +692,7 @@ static int cal_camerarx_sd_get_fmt(struct v4l2_subdev *sd,
>  }
>  
>  static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
> -				   struct v4l2_subdev_pad_config *cfg,
> +				   struct v4l2_subdev_config *cfg,
>  				   struct v4l2_subdev_format *format)
>  {
>  	struct cal_camerarx *phy = to_cal_camerarx(sd);
> @@ -742,7 +742,7 @@ static int cal_camerarx_sd_set_fmt(struct v4l2_subdev *sd,
>  }
>  
>  static int cal_camerarx_sd_init_cfg(struct v4l2_subdev *sd,
> -				    struct v4l2_subdev_pad_config *cfg)
> +				    struct v4l2_subdev_config *cfg)
>  {
>  	struct v4l2_subdev_format format = {
>  		.which = cfg ? V4L2_SUBDEV_FORMAT_TRY
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 956dafab43d4..248fa4ee9356 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -26,19 +26,18 @@
>  #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
>  static int subdev_fh_init(struct v4l2_subdev_fh *fh, struct v4l2_subdev *sd)
>  {
> -	if (sd->entity.num_pads) {
> -		fh->pad = v4l2_subdev_alloc_pad_config(sd);
> -		if (fh->pad == NULL)
> -			return -ENOMEM;
> -	}
> +	int ret;
> +
> +	ret = v4l2_subdev_init_config(sd, &fh->cfg);
> +	if (ret)
> +		return ret;

You can do:

	return v4l2_subdev_init_config(sd, &fh->cfg);

>  
>  	return 0;
>  }
>  
>  static void subdev_fh_free(struct v4l2_subdev_fh *fh)
>  {
> -	v4l2_subdev_free_pad_config(fh->pad);
> -	fh->pad = NULL;
> +	v4l2_subdev_uninit_config(&fh->cfg);
>  }
>  
>  static int subdev_open(struct file *file)
> @@ -146,7 +145,7 @@ static inline int check_pad(struct v4l2_subdev *sd, u32 pad)
>  	return 0;
>  }
>  
> -static int check_cfg(u32 which, struct v4l2_subdev_pad_config *cfg)
> +static int check_cfg(u32 which, struct v4l2_subdev_config *cfg)
>  {
>  	if (which == V4L2_SUBDEV_FORMAT_TRY && !cfg)
>  		return -EINVAL;
> @@ -155,7 +154,7 @@ static int check_cfg(u32 which, struct v4l2_subdev_pad_config *cfg)
>  }
>  
>  static inline int check_format(struct v4l2_subdev *sd,
> -			       struct v4l2_subdev_pad_config *cfg,
> +			       struct v4l2_subdev_config *cfg,
>  			       struct v4l2_subdev_format *format)
>  {
>  	if (!format)
> @@ -166,7 +165,7 @@ static inline int check_format(struct v4l2_subdev *sd,
>  }
>  
>  static int call_get_fmt(struct v4l2_subdev *sd,
> -			struct v4l2_subdev_pad_config *cfg,
> +			struct v4l2_subdev_config *cfg,
>  			struct v4l2_subdev_format *format)
>  {
>  	return check_format(sd, cfg, format) ? :
> @@ -174,7 +173,7 @@ static int call_get_fmt(struct v4l2_subdev *sd,
>  }
>  
>  static int call_set_fmt(struct v4l2_subdev *sd,
> -			struct v4l2_subdev_pad_config *cfg,
> +			struct v4l2_subdev_config *cfg,
>  			struct v4l2_subdev_format *format)
>  {
>  	return check_format(sd, cfg, format) ? :
> @@ -182,7 +181,7 @@ static int call_set_fmt(struct v4l2_subdev *sd,
>  }
>  
>  static int call_enum_mbus_code(struct v4l2_subdev *sd,
> -			       struct v4l2_subdev_pad_config *cfg,
> +			       struct v4l2_subdev_config *cfg,
>  			       struct v4l2_subdev_mbus_code_enum *code)
>  {
>  	if (!code)
> @@ -194,7 +193,7 @@ static int call_enum_mbus_code(struct v4l2_subdev *sd,
>  }
>  
>  static int call_enum_frame_size(struct v4l2_subdev *sd,
> -				struct v4l2_subdev_pad_config *cfg,
> +				struct v4l2_subdev_config *cfg,
>  				struct v4l2_subdev_frame_size_enum *fse)
>  {
>  	if (!fse)
> @@ -229,7 +228,7 @@ static int call_s_frame_interval(struct v4l2_subdev *sd,
>  }
>  
>  static int call_enum_frame_interval(struct v4l2_subdev *sd,
> -				    struct v4l2_subdev_pad_config *cfg,
> +				    struct v4l2_subdev_config *cfg,
>  				    struct v4l2_subdev_frame_interval_enum *fie)
>  {
>  	if (!fie)
> @@ -241,7 +240,7 @@ static int call_enum_frame_interval(struct v4l2_subdev *sd,
>  }
>  
>  static inline int check_selection(struct v4l2_subdev *sd,
> -				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_config *cfg,
>  				  struct v4l2_subdev_selection *sel)
>  {
>  	if (!sel)
> @@ -252,7 +251,7 @@ static inline int check_selection(struct v4l2_subdev *sd,
>  }
>  
>  static int call_get_selection(struct v4l2_subdev *sd,
> -			      struct v4l2_subdev_pad_config *cfg,
> +			      struct v4l2_subdev_config *cfg,
>  			      struct v4l2_subdev_selection *sel)
>  {
>  	return check_selection(sd, cfg, sel) ? :
> @@ -260,7 +259,7 @@ static int call_get_selection(struct v4l2_subdev *sd,
>  }
>  
>  static int call_set_selection(struct v4l2_subdev *sd,
> -			      struct v4l2_subdev_pad_config *cfg,
> +			      struct v4l2_subdev_config *cfg,
>  			      struct v4l2_subdev_selection *sel)
>  {
>  	return check_selection(sd, cfg, sel) ? :
> @@ -506,7 +505,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  
>  		memset(format->reserved, 0, sizeof(format->reserved));
>  		memset(format->format.reserved, 0, sizeof(format->format.reserved));
> -		return v4l2_subdev_call(sd, pad, get_fmt, subdev_fh->pad, format);
> +		return v4l2_subdev_call(sd, pad, get_fmt, &subdev_fh->cfg, format);
>  	}
>  
>  	case VIDIOC_SUBDEV_S_FMT: {
> @@ -517,7 +516,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  
>  		memset(format->reserved, 0, sizeof(format->reserved));
>  		memset(format->format.reserved, 0, sizeof(format->format.reserved));
> -		return v4l2_subdev_call(sd, pad, set_fmt, subdev_fh->pad, format);
> +		return v4l2_subdev_call(sd, pad, set_fmt, &subdev_fh->cfg, format);
>  	}
>  
>  	case VIDIOC_SUBDEV_G_CROP: {
> @@ -531,7 +530,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  		sel.target = V4L2_SEL_TGT_CROP;
>  
>  		rval = v4l2_subdev_call(
> -			sd, pad, get_selection, subdev_fh->pad, &sel);
> +			sd, pad, get_selection, &subdev_fh->cfg, &sel);
>  
>  		crop->rect = sel.r;
>  
> @@ -553,7 +552,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  		sel.r = crop->rect;
>  
>  		rval = v4l2_subdev_call(
> -			sd, pad, set_selection, subdev_fh->pad, &sel);
> +			sd, pad, set_selection, &subdev_fh->cfg, &sel);
>  
>  		crop->rect = sel.r;
>  
> @@ -564,7 +563,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  		struct v4l2_subdev_mbus_code_enum *code = arg;
>  
>  		memset(code->reserved, 0, sizeof(code->reserved));
> -		return v4l2_subdev_call(sd, pad, enum_mbus_code, subdev_fh->pad,
> +		return v4l2_subdev_call(sd, pad, enum_mbus_code, &subdev_fh->cfg,
>  					code);
>  	}
>  
> @@ -572,7 +571,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  		struct v4l2_subdev_frame_size_enum *fse = arg;
>  
>  		memset(fse->reserved, 0, sizeof(fse->reserved));
> -		return v4l2_subdev_call(sd, pad, enum_frame_size, subdev_fh->pad,
> +		return v4l2_subdev_call(sd, pad, enum_frame_size, &subdev_fh->cfg,
>  					fse);
>  	}
>  
> @@ -597,7 +596,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  		struct v4l2_subdev_frame_interval_enum *fie = arg;
>  
>  		memset(fie->reserved, 0, sizeof(fie->reserved));
> -		return v4l2_subdev_call(sd, pad, enum_frame_interval, subdev_fh->pad,
> +		return v4l2_subdev_call(sd, pad, enum_frame_interval, &subdev_fh->cfg,
>  					fie);
>  	}
>  
> @@ -606,7 +605,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  
>  		memset(sel->reserved, 0, sizeof(sel->reserved));
>  		return v4l2_subdev_call(
> -			sd, pad, get_selection, subdev_fh->pad, sel);
> +			sd, pad, get_selection, &subdev_fh->cfg, sel);
>  	}
>  
>  	case VIDIOC_SUBDEV_S_SELECTION: {
> @@ -617,7 +616,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  
>  		memset(sel->reserved, 0, sizeof(sel->reserved));
>  		return v4l2_subdev_call(
> -			sd, pad, set_selection, subdev_fh->pad, sel);
> +			sd, pad, set_selection, &subdev_fh->cfg, sel);
>  	}
>  
>  	case VIDIOC_G_EDID: {
> @@ -892,35 +891,35 @@ int v4l2_subdev_link_validate(struct media_link *link)
>  }
>  EXPORT_SYMBOL_GPL(v4l2_subdev_link_validate);
>  
> -struct v4l2_subdev_pad_config *
> -v4l2_subdev_alloc_pad_config(struct v4l2_subdev *sd)
> +int v4l2_subdev_init_config(struct v4l2_subdev *sd, struct v4l2_subdev_config *cfg)
>  {
> -	struct v4l2_subdev_pad_config *cfg;
>  	int ret;
>  
> -	if (!sd->entity.num_pads)
> -		return NULL;
> -
> -	cfg = kvmalloc_array(sd->entity.num_pads, sizeof(*cfg),
> -			     GFP_KERNEL | __GFP_ZERO);
> -	if (!cfg)
> -		return NULL;
> +	if (sd->entity.num_pads) {
> +		cfg->pad_configs = kvmalloc_array(sd->entity.num_pads, sizeof(*cfg->pad_configs),
> +				     GFP_KERNEL | __GFP_ZERO);
> +		if (!cfg->pad_configs)
> +			return -ENOMEM;
> +	} else {
> +		cfg->pad_configs = NULL;
> +	}
>  
>  	ret = v4l2_subdev_call(sd, pad, init_cfg, cfg);
>  	if (ret < 0 && ret != -ENOIOCTLCMD) {
> -		kvfree(cfg);
> -		return NULL;
> +		kvfree(cfg->pad_configs);

You can call v4l2_subdev_uninit_config() here...

> +		return ret;
>  	}
>  
> -	return cfg;
> +	return 0;
>  }
> -EXPORT_SYMBOL_GPL(v4l2_subdev_alloc_pad_config);
> +EXPORT_SYMBOL_GPL(v4l2_subdev_init_config);
>  
> -void v4l2_subdev_free_pad_config(struct v4l2_subdev_pad_config *cfg)
> +void v4l2_subdev_uninit_config(struct v4l2_subdev_config *cfg)
>  {
> -	kvfree(cfg);
> +	kvfree(cfg->pad_configs);

Please set cfg->pad_configs to NULL here.


>  }
> -EXPORT_SYMBOL_GPL(v4l2_subdev_free_pad_config);
> +EXPORT_SYMBOL_GPL(v4l2_subdev_uninit_config);
> +
>  #endif /* CONFIG_MEDIA_CONTROLLER */
>  
>  void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index d0e9a5bdb08b..1873e527987a 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -623,6 +623,10 @@ struct v4l2_subdev_pad_config {
>  	struct v4l2_rect try_compose;
>  };
>  
> +struct v4l2_subdev_config {
> +	struct v4l2_subdev_pad_config *pad_configs;

Could this be called just "pad"?

> +};
> +
>  /**
>   * struct v4l2_subdev_pad_ops - v4l2-subdev pad level operations
>   *
> @@ -687,27 +691,27 @@ struct v4l2_subdev_pad_config {
>   */
>  struct v4l2_subdev_pad_ops {
>  	int (*init_cfg)(struct v4l2_subdev *sd,
> -			struct v4l2_subdev_pad_config *cfg);
> +			struct v4l2_subdev_config *cfg);
>  	int (*enum_mbus_code)(struct v4l2_subdev *sd,
> -			      struct v4l2_subdev_pad_config *cfg,
> +			      struct v4l2_subdev_config *cfg,
>  			      struct v4l2_subdev_mbus_code_enum *code);
>  	int (*enum_frame_size)(struct v4l2_subdev *sd,
> -			       struct v4l2_subdev_pad_config *cfg,
> +			       struct v4l2_subdev_config *cfg,
>  			       struct v4l2_subdev_frame_size_enum *fse);
>  	int (*enum_frame_interval)(struct v4l2_subdev *sd,
> -				   struct v4l2_subdev_pad_config *cfg,
> +				   struct v4l2_subdev_config *cfg,
>  				   struct v4l2_subdev_frame_interval_enum *fie);
>  	int (*get_fmt)(struct v4l2_subdev *sd,
> -		       struct v4l2_subdev_pad_config *cfg,
> +		       struct v4l2_subdev_config *cfg,
>  		       struct v4l2_subdev_format *format);
>  	int (*set_fmt)(struct v4l2_subdev *sd,
> -		       struct v4l2_subdev_pad_config *cfg,
> +		       struct v4l2_subdev_config *cfg,
>  		       struct v4l2_subdev_format *format);
>  	int (*get_selection)(struct v4l2_subdev *sd,
> -			     struct v4l2_subdev_pad_config *cfg,
> +			     struct v4l2_subdev_config *cfg,
>  			     struct v4l2_subdev_selection *sel);
>  	int (*set_selection)(struct v4l2_subdev *sd,
> -			     struct v4l2_subdev_pad_config *cfg,
> +			     struct v4l2_subdev_config *cfg,
>  			     struct v4l2_subdev_selection *sel);
>  	int (*get_edid)(struct v4l2_subdev *sd, struct v4l2_edid *edid);
>  	int (*set_edid)(struct v4l2_subdev *sd, struct v4l2_edid *edid);
> @@ -925,7 +929,7 @@ struct v4l2_subdev_fh {
>  	struct v4l2_fh vfh;
>  	struct module *owner;
>  #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
> -	struct v4l2_subdev_pad_config *pad;
> +	struct v4l2_subdev_config cfg;
>  #endif
>  };
>  
> @@ -950,12 +954,12 @@ struct v4l2_subdev_fh {
>   */
>  static inline struct v4l2_mbus_framefmt *
>  v4l2_subdev_get_try_format(struct v4l2_subdev *sd,
> -			   struct v4l2_subdev_pad_config *cfg,
> +			   struct v4l2_subdev_config *cfg,
>  			   unsigned int pad)
>  {
>  	if (WARN_ON(pad >= sd->entity.num_pads))
>  		pad = 0;
> -	return &cfg[pad].try_fmt;
> +	return &cfg->pad_configs[pad].try_fmt;
>  }
>  
>  /**
> @@ -968,12 +972,12 @@ v4l2_subdev_get_try_format(struct v4l2_subdev *sd,
>   */
>  static inline struct v4l2_rect *
>  v4l2_subdev_get_try_crop(struct v4l2_subdev *sd,
> -			 struct v4l2_subdev_pad_config *cfg,
> +			 struct v4l2_subdev_config *cfg,
>  			 unsigned int pad)
>  {
>  	if (WARN_ON(pad >= sd->entity.num_pads))
>  		pad = 0;
> -	return &cfg[pad].try_crop;
> +	return &cfg->pad_configs[pad].try_crop;
>  }
>  
>  /**
> @@ -986,12 +990,12 @@ v4l2_subdev_get_try_crop(struct v4l2_subdev *sd,
>   */
>  static inline struct v4l2_rect *
>  v4l2_subdev_get_try_compose(struct v4l2_subdev *sd,
> -			    struct v4l2_subdev_pad_config *cfg,
> +			    struct v4l2_subdev_config *cfg,
>  			    unsigned int pad)
>  {
>  	if (WARN_ON(pad >= sd->entity.num_pads))
>  		pad = 0;
> -	return &cfg[pad].try_compose;
> +	return &cfg->pad_configs[pad].try_compose;
>  }
>  
>  #endif
> @@ -1093,20 +1097,17 @@ int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd,
>  int v4l2_subdev_link_validate(struct media_link *link);
>  
>  /**
> - * v4l2_subdev_alloc_pad_config - Allocates memory for pad config
> + * v4l2_subdev_init_config - initialize v4l2_subdev_config
>   *
> - * @sd: pointer to struct v4l2_subdev
> + * Must call v4l2_subdev_uninit_config() when config is no longer needed.
>   */
> -struct
> -v4l2_subdev_pad_config *v4l2_subdev_alloc_pad_config(struct v4l2_subdev *sd);
> +int v4l2_subdev_init_config(struct v4l2_subdev *sd, struct v4l2_subdev_config *cfg);
>  
>  /**
> - * v4l2_subdev_free_pad_config - Frees memory allocated by
> - *	v4l2_subdev_alloc_pad_config().
> - *
> - * @cfg: pointer to &struct v4l2_subdev_pad_config
> + * v4l2_subdev_uninit_config - uninitialize v4l2_subdev_config
>   */
> -void v4l2_subdev_free_pad_config(struct v4l2_subdev_pad_config *cfg);
> +void v4l2_subdev_uninit_config(struct v4l2_subdev_config *cfg);
> +
>  #endif /* CONFIG_MEDIA_CONTROLLER */
>  
>  /**

-- 
Kind regards,

Sakari Ailus

Re: [PATCH] RFC: media: v4l2-subdev: add subdev-wide config struct

[Sakari Ailus]

A few more more mundane comments...

On Tue, Apr 20, 2021 at 06:35:10PM +0300, Sakari Ailus wrote:

...

> > +int v4l2_subdev_init_config(struct v4l2_subdev *sd, struct v4l2_subdev_config *cfg)
> >  {
> > -	struct v4l2_subdev_pad_config *cfg;
> >  	int ret;
> >  
> > -	if (!sd->entity.num_pads)
> > -		return NULL;
> > -
> > -	cfg = kvmalloc_array(sd->entity.num_pads, sizeof(*cfg),
> > -			     GFP_KERNEL | __GFP_ZERO);
> > -	if (!cfg)
> > -		return NULL;
> > +	if (sd->entity.num_pads) {
> > +		cfg->pad_configs = kvmalloc_array(sd->entity.num_pads, sizeof(*cfg->pad_configs),
> > +				     GFP_KERNEL | __GFP_ZERO);

Please also pay attention to line length and aligning arguments.

...

> > @@ -1093,20 +1097,17 @@ int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd,
> >  int v4l2_subdev_link_validate(struct media_link *link);
> >  
> >  /**
> > - * v4l2_subdev_alloc_pad_config - Allocates memory for pad config
> > + * v4l2_subdev_init_config - initialize v4l2_subdev_config
> >   *
> > - * @sd: pointer to struct v4l2_subdev
> > + * Must call v4l2_subdev_uninit_config() when config is no longer needed.
> >   */
> > -struct
> > -v4l2_subdev_pad_config *v4l2_subdev_alloc_pad_config(struct v4l2_subdev *sd);
> > +int v4l2_subdev_init_config(struct v4l2_subdev *sd, struct v4l2_subdev_config *cfg);

This should be wrapped, too... there are some others as well in this patch
I think.

-- 
Sakari Ailus