Re: [PATCH v14 04/11] media: uvcvideo: Split uvc_control_mapping.size to v4l2 and data size

Laurent Pinchart
2023-12-08T14:15:06Z

Hi Yunke,

Thank you for the patch.

On Fri, Dec 01, 2023 at 04:18:55PM +0900, Yunke Cao wrote:
> Rename the existing size to data_size to represent uvc control data size,
> add a separate field for v4l2 control size. v4l2 control size will be
> used the compound controls.

s/uvc/UVC/ and s/v4l2/V4L2/ in the whole commit message.

> Also modify the uvc driver documents to clarify the size in
> uvc_xu_control_mapping corresponds to the uvc control data size.
>
> Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
> Signed-off-by: Yunke Cao <yunkec@google.com>
> ---
> Changelog since v11:
> - No change.
> Changelog since v10:
> - Added Reviewed-by from Daniel Scally.
> Changelog since v9:
> - No change.
> Changelog since v8:
> - No change.
> Changelog since v7:
> - Newly added patch.
>
> .../userspace-api/media/drivers/uvcvideo.rst | 2 +-
> drivers/media/usb/uvc/uvc_ctrl.c | 80 +++++++++----------
> drivers/media/usb/uvc/uvc_v4l2.c | 2 +-
> drivers/media/usb/uvc/uvcvideo.h | 6 +-
> 4 files changed, 47 insertions(+), 43 deletions(-)
>
> diff --git a/Documentation/userspace-api/media/drivers/uvcvideo.rst b/Documentation/userspace-api/media/drivers/uvcvideo.rst
> index a290f9fadae9..aab4304e6bb5 100644
> --- a/Documentation/userspace-api/media/drivers/uvcvideo.rst
> +++ b/Documentation/userspace-api/media/drivers/uvcvideo.rst
> @@ -157,7 +157,7 @@ Argument: struct uvc_xu_control_mapping
> __u8 name[32] V4L2 control name
> __u8 entity[16] UVC extension unit GUID
> __u8 selector UVC control selector
> - __u8 size V4L2 control size (in bits)
> + __u8 size UVC control data size (in bits)

The V4L2 and UVC sizes are identical for all controls mapped through
this mechanism, right ?

> __u8 offset V4L2 control offset (in bits)

If the size if the "UVC control data size", shouldn't this be the "UVC
control data offset" ?

> enum v4l2_ctrl_type
> v4l2_type V4L2 control type
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 4a685532f7eb..98254b93eb46 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -464,7 +464,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_BRIGHTNESS,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_BRIGHTNESS_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_SIGNED,
> @@ -473,7 +473,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_CONTRAST,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_CONTRAST_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -482,7 +482,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_HUE,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_HUE_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_SIGNED,
> @@ -493,7 +493,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_SATURATION,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_SATURATION_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -502,7 +502,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_SHARPNESS,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_SHARPNESS_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -511,7 +511,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_GAMMA,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_GAMMA_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -520,7 +520,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_BACKLIGHT_COMPENSATION,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_BACKLIGHT_COMPENSATION_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -529,7 +529,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_GAIN,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_GAIN_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -538,7 +538,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_HUE_AUTO,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_HUE_AUTO_CONTROL,
> - .size = 1,
> + .data_size = 1,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_BOOLEAN,
> .data_type = UVC_CTRL_DATA_TYPE_BOOLEAN,
> @@ -548,7 +548,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_EXPOSURE_AUTO,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_AE_MODE_CONTROL,
> - .size = 4,
> + .data_size = 4,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_BITMASK,
> @@ -561,7 +561,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_EXPOSURE_AUTO_PRIORITY,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_AE_PRIORITY_CONTROL,
> - .size = 1,
> + .data_size = 1,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_BOOLEAN,
> .data_type = UVC_CTRL_DATA_TYPE_BOOLEAN,
> @@ -570,7 +570,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_EXPOSURE_ABSOLUTE,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_EXPOSURE_TIME_ABSOLUTE_CONTROL,
> - .size = 32,
> + .data_size = 32,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -581,7 +581,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_AUTO_WHITE_BALANCE,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_WHITE_BALANCE_TEMPERATURE_AUTO_CONTROL,
> - .size = 1,
> + .data_size = 1,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_BOOLEAN,
> .data_type = UVC_CTRL_DATA_TYPE_BOOLEAN,
> @@ -591,7 +591,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_WHITE_BALANCE_TEMPERATURE,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_WHITE_BALANCE_TEMPERATURE_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -602,7 +602,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_AUTO_WHITE_BALANCE,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_WHITE_BALANCE_COMPONENT_AUTO_CONTROL,
> - .size = 1,
> + .data_size = 1,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_BOOLEAN,
> .data_type = UVC_CTRL_DATA_TYPE_BOOLEAN,
> @@ -613,7 +613,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_BLUE_BALANCE,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_WHITE_BALANCE_COMPONENT_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_SIGNED,
> @@ -624,7 +624,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_RED_BALANCE,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_WHITE_BALANCE_COMPONENT_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 16,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_SIGNED,
> @@ -635,7 +635,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_FOCUS_ABSOLUTE,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_FOCUS_ABSOLUTE_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -646,7 +646,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_FOCUS_AUTO,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_FOCUS_AUTO_CONTROL,
> - .size = 1,
> + .data_size = 1,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_BOOLEAN,
> .data_type = UVC_CTRL_DATA_TYPE_BOOLEAN,
> @@ -656,7 +656,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_IRIS_ABSOLUTE,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_IRIS_ABSOLUTE_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -665,7 +665,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_IRIS_RELATIVE,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_IRIS_RELATIVE_CONTROL,
> - .size = 8,
> + .data_size = 8,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_SIGNED,
> @@ -674,7 +674,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_ZOOM_ABSOLUTE,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_ZOOM_ABSOLUTE_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_UNSIGNED,
> @@ -683,7 +683,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_ZOOM_CONTINUOUS,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_ZOOM_RELATIVE_CONTROL,
> - .size = 0,
> + .data_size = 0,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_SIGNED,
> @@ -694,7 +694,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_PAN_ABSOLUTE,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_PANTILT_ABSOLUTE_CONTROL,
> - .size = 32,
> + .data_size = 32,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_SIGNED,
> @@ -703,7 +703,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_TILT_ABSOLUTE,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_PANTILT_ABSOLUTE_CONTROL,
> - .size = 32,
> + .data_size = 32,
> .offset = 32,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_SIGNED,
> @@ -712,7 +712,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_PAN_SPEED,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_PANTILT_RELATIVE_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_SIGNED,
> @@ -723,7 +723,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_TILT_SPEED,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_PANTILT_RELATIVE_CONTROL,
> - .size = 16,
> + .data_size = 16,
> .offset = 16,
> .v4l2_type = V4L2_CTRL_TYPE_INTEGER,
> .data_type = UVC_CTRL_DATA_TYPE_SIGNED,
> @@ -734,7 +734,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_PRIVACY,
> .entity = UVC_GUID_UVC_CAMERA,
> .selector = UVC_CT_PRIVACY_CONTROL,
> - .size = 1,
> + .data_size = 1,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_BOOLEAN,
> .data_type = UVC_CTRL_DATA_TYPE_BOOLEAN,
> @@ -743,7 +743,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .id = V4L2_CID_PRIVACY,
> .entity = UVC_GUID_EXT_GPIO_CONTROLLER,
> .selector = UVC_CT_PRIVACY_CONTROL,
> - .size = 1,
> + .data_size = 1,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_BOOLEAN,
> .data_type = UVC_CTRL_DATA_TYPE_BOOLEAN,
> @@ -754,7 +754,7 @@ const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited = {
> .id = V4L2_CID_POWER_LINE_FREQUENCY,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_POWER_LINE_FREQUENCY_CONTROL,
> - .size = 2,
> + .data_size = 2,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_ENUM,
> @@ -766,7 +766,7 @@ const struct uvc_control_mapping uvc_ctrl_power_line_mapping_uvc11 = {
> .id = V4L2_CID_POWER_LINE_FREQUENCY,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_POWER_LINE_FREQUENCY_CONTROL,
> - .size = 2,
> + .data_size = 2,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_ENUM,
> @@ -783,7 +783,7 @@ static const struct uvc_control_mapping uvc_ctrl_power_line_mapping_uvc15 = {
> .id = V4L2_CID_POWER_LINE_FREQUENCY,
> .entity = UVC_GUID_UVC_PROCESSING,
> .selector = UVC_PU_POWER_LINE_FREQUENCY_CONTROL,
> - .size = 2,
> + .data_size = 2,
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_ENUM,
> @@ -816,7 +816,7 @@ static inline void uvc_clear_bit(u8 *data, int bit)
> }
>
> /*
> - * Extract the bit string specified by mapping->offset and mapping->size
> + * Extract the bit string specified by mapping->offset and mapping->data_size
> * from the little-endian data stored at 'data' and return the result as
> * a signed 32bit integer. Sign extension will be performed if the mapping
> * references a signed data type.
> @@ -824,7 +824,7 @@ static inline void uvc_clear_bit(u8 *data, int bit)
> static s32 uvc_get_le_value(struct uvc_control_mapping *mapping,
> u8 query, const u8 *data)
> {
> - int bits = mapping->size;
> + int bits = mapping->data_size;
> int offset = mapping->offset;
> s32 value = 0;
> u8 mask;
> @@ -847,19 +847,19 @@ static s32 uvc_get_le_value(struct uvc_control_mapping *mapping,
>
> /* Sign-extend the value if needed. */
> if (mapping->data_type == UVC_CTRL_DATA_TYPE_SIGNED)
> - value |= -(value & (1 << (mapping->size - 1)));
> + value |= -(value & (1 << (mapping->data_size - 1)));
>
> return value;
> }
>
> /*
> - * Set the bit string specified by mapping->offset and mapping->size
> + * Set the bit string specified by mapping->offset and mapping->data_size
> * in the little-endian data stored at 'data' to the value 'value'.
> */
> static void uvc_set_le_value(struct uvc_control_mapping *mapping,
> s32 value, u8 *data)
> {
> - int bits = mapping->size;
> + int bits = mapping->data_size;
> int offset = mapping->offset;
> u8 mask;
>
> @@ -2039,7 +2039,7 @@ int uvc_ctrl_set(struct uvc_fh *handle,
> * needs to be loaded from the device to perform the read-modify-write
> * operation.
> */
> - if ((ctrl->info.size * 8) != mapping->size) {
> + if ((ctrl->info.size * 8) != mapping->data_size) {
> ret = __uvc_ctrl_load_cur(chain, ctrl);
> if (ret < 0)
> return ret;
> @@ -2546,8 +2546,8 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
> }
>
> /* Validate the user-provided bit-size and offset */
> - if (mapping->size > 32 ||
> - mapping->offset + mapping->size > ctrl->info.size * 8) {
> + if (mapping->data_size > 32 ||
> + mapping->offset + mapping->data_size > ctrl->info.size * 8) {
> ret = -EINVAL;
> goto done;
> }
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index 5a88847bfbfe..ff72caf7bc9e 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -122,7 +122,7 @@ static int uvc_ioctl_xu_ctrl_map(struct uvc_video_chain *chain,
> }
> memcpy(map->entity, xmap->entity, sizeof(map->entity));
> map->selector = xmap->selector;
> - map->size = xmap->size;
> + map->data_size = xmap->size;
> map->offset = xmap->offset;
> map->v4l2_type = xmap->v4l2_type;
> map->data_type = xmap->data_type;
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index 5091085fcfb0..7bc41270ed94 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -110,7 +110,11 @@ struct uvc_control_mapping {
> u8 entity[16];
> u8 selector;
>
> - u8 size;
> + /* Size of the v4l2 control. Required for compound controls. */
> + u8 v4l2_size;

Let's introduce this field in the patch that uses it. The commit message
needs to be updated to explain that this patch renames the size field to
data_size to prepare for adding another size field for compound
controls.

> + /* UVC data size. Required for all controls. */

"UVC data size" is not very clear. Let me attempt to write a more
precise description:

/*
* Size of the control data in the payload of the UVC control GET and
* SET requests, expressed in bits.
*/

Is this correct ?

> + u8 data_size;
> +
> u8 offset;
> enum v4l2_ctrl_type v4l2_type;
> u32 data_type;

--
Regards,

Laurent Pinchart