Add format description for the PiSP Back End configuration parameter
buffer.
Signed-off-by: Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx>
Reviewed-by: Naushir Patuck <naush@xxxxxxxxxxxxxxx>
---
.../userspace-api/media/v4l/meta-formats.rst | 1 +
.../media/v4l/metafmt-pisp-be.rst | 46 +++++++++++++++++++
drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
include/uapi/linux/videodev2.h | 3 ++
4 files changed, 51 insertions(+)
create mode 100644 Documentation/userspace-api/media/v4l/metafmt-pisp-be.rst
diff --git a/Documentation/userspace-api/media/v4l/meta-formats.rst b/Documentation/userspace-api/media/v4l/meta-formats.rst
index c23aac823d2c..c6e56b5888bc 100644
--- a/Documentation/userspace-api/media/v4l/meta-formats.rst
+++ b/Documentation/userspace-api/media/v4l/meta-formats.rst
@@ -15,6 +15,7 @@ These formats are used for the :ref:`metadata` interface only.
metafmt-d4xx
metafmt-generic
metafmt-intel-ipu3
+ metafmt-pisp-be
metafmt-rkisp1
metafmt-uvc
metafmt-vivid
diff --git a/Documentation/userspace-api/media/v4l/metafmt-pisp-be.rst b/Documentation/userspace-api/media/v4l/metafmt-pisp-be.rst
new file mode 100644
index 000000000000..f3d30ba989b3
--- /dev/null
+++ b/Documentation/userspace-api/media/v4l/metafmt-pisp-be.rst
@@ -0,0 +1,46 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+.. _v4l2-meta-fmt-rpi-be-cfg:
+
+************************
+V4L2_META_FMT_RPI_BE_CFG
+************************
+
+Raspberry Pi PiSP Back End configuration format
+===============================================
+
+The Raspberry Pi PiSP Back End memory-to-memory image signal processor is
+configured by userspace by providing a buffer of configuration parameters
+to the `pispbe-config` output video device node using the
+:c:type:`v4l2_meta_format` interface.
+
+The PiSP Back End processes images in tiles, and its configuration requires
+specifying two different sets of parameters by populating the members of
+:c:type:`pisp_be_tiles_config` defined in the ``pisp_be_config.h`` header file.
+
+The `Raspberry Pi PiSP technical specification
+<https://datasheets.raspberrypi.com/camera/raspberry-pi-image-signal-processor-specification.pdf>_`
+provide detailed description of the ISP back end configuration and programming
+model.
+
+Global configuration data
+-------------------------
+
+The global configuration data describe how the pixels in a particular image are
+to be processed and is therefore shared across all the tiles of the image. So
+for example, LSC (Lens Shading Correction) or Denoise parameters would be common
+across all tiles from the same frame.
+
+Global configuration data are passed to the ISP by populating the member of
+:c:type:`pisp_be_config`.
+
+Tile parameters
+---------------
+
+As the ISP processes images in tiles, each set of tiles parameters describe how
+a single tile in an image is going to be processed. A single set of tile
+parameters consist of 160 bytes of data and to process a batch of tiles several
+sets of tiles parameters are required.
+
+Tiles parameters are passed to the ISP by populating the member of
+:c:type:`pisp_tile` and the :c:type:`num_tiles` field.
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index ee97643ff3a7..7c684788997c 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -1465,6 +1465,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
case V4L2_PIX_FMT_Y210: descr = "10-bit YUYV Packed"; break;
case V4L2_PIX_FMT_Y212: descr = "12-bit YUYV Packed"; break;
case V4L2_PIX_FMT_Y216: descr = "16-bit YUYV Packed"; break;
+ case V4L2_META_FMT_RPI_BE_CFG: descr = "RPi PiSP BE Config format"; break;
case V4L2_META_FMT_GENERIC_8: descr = "8-bit Generic Metadata"; break;
case V4L2_META_FMT_GENERIC_CSI2_10: descr = "8-bit Generic Meta, 10b CSI-2"; break;
case V4L2_META_FMT_GENERIC_CSI2_12: descr = "8-bit Generic Meta, 12b CSI-2"; break;
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index dd6876380fe3..530898b5b342 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -843,6 +843,9 @@ struct v4l2_pix_format {
#define V4L2_META_FMT_RK_ISP1_PARAMS v4l2_fourcc('R', 'K', '1', 'P') /* Rockchip ISP1 3A Parameters */
#define V4L2_META_FMT_RK_ISP1_STAT_3A v4l2_fourcc('R', 'K', '1', 'S') /* Rockchip ISP1 3A Statistics */
+/* Vendor specific - used for RaspberryPi PiSP */
+#define V4L2_META_FMT_RPI_BE_CFG v4l2_fourcc('R', 'P', 'B', 'C') /* PiSP BE configuration */
+
#ifdef __KERNEL__
/*
* Line-based metadata formats. Remember to update v4l_fill_fmtdesc() when
--
2.44.0
