[PATCH v6 2/8] media: v4l: Add definition for Allwinner's MB32-tiled NV12 format

[Paul Kocialkowski]

This introduces support for Allwinner's MB32-tiled NV12 format, where
each plane is divided into macroblocks of 32x32 pixels. Hence, the size
of each plane has to be aligned to 32 bytes. The pixels inside each
macroblock are coded as they would be if the macroblock was a single
plane, line after line.

The MB32-tiled NV12 format is used by the video engine on Allwinner
platforms: it is the default format for decoded frames (and the only one
available in the oldest supported platforms).

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
---
 Documentation/media/uapi/v4l/pixfmt-reserved.rst | 15 ++++++++++++++-
 drivers/media/v4l2-core/v4l2-ioctl.c             |  1 +
 include/uapi/linux/videodev2.h                   |  1 +
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/Documentation/media/uapi/v4l/pixfmt-reserved.rst b/Documentation/media/uapi/v4l/pixfmt-reserved.rst
index 38af1472a4b4..9a68b6a787bf 100644
--- a/Documentation/media/uapi/v4l/pixfmt-reserved.rst
+++ b/Documentation/media/uapi/v4l/pixfmt-reserved.rst
@@ -243,7 +243,20 @@ please make a proposal on the linux-media mailing list.
 	It is an opaque intermediate format and the MDP hardware must be
 	used to convert ``V4L2_PIX_FMT_MT21C`` to ``V4L2_PIX_FMT_NV12M``,
 	``V4L2_PIX_FMT_YUV420M`` or ``V4L2_PIX_FMT_YVU420``.
-
+    * .. _V4L2-PIX-FMT-MB32-NV12:
+
+      - ``V4L2_PIX_FMT_MB32_NV12``
+      - 'MN12'
+      - Two-planar NV12-based format used by the Allwinner video engine
+        hardware, with 32x32 tiles for the luminance plane and 32x64 tiles
+        for the chrominance plane. Each tile is a linear pixel data
+        representation within its own bounds. Each tile follows the previous
+        one linearly (as in, from left to right, top to bottom).
+
+        The frame dimensions are aligned to match an integer number of
+        tiles, resulting in 32-aligned resolutions for the luminance plane
+        and 16-aligned resolutions for the chrominance plane (with 2x2
+        subsampling).
 
 .. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
 
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 68e914b83a03..7e1c200de10d 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -1331,6 +1331,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
 		case V4L2_PIX_FMT_SE401:	descr = "GSPCA SE401"; break;
 		case V4L2_PIX_FMT_S5C_UYVY_JPG:	descr = "S5C73MX interleaved UYVY/JPEG"; break;
 		case V4L2_PIX_FMT_MT21C:	descr = "Mediatek Compressed Format"; break;
+		case V4L2_PIX_FMT_MB32_NV12:	descr = "Allwinner tiled NV12 format"; break;
 		default:
 			WARN(1, "Unknown pixelformat 0x%08x\n", fmt->pixelformat);
 			if (fmt->description[0])
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index d171361ed9b3..453d27142e31 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -670,6 +670,7 @@ struct v4l2_pix_format {
 #define V4L2_PIX_FMT_Z16      v4l2_fourcc('Z', '1', '6', ' ') /* Depth data 16-bit */
 #define V4L2_PIX_FMT_MT21C    v4l2_fourcc('M', 'T', '2', '1') /* Mediatek compressed block mode  */
 #define V4L2_PIX_FMT_INZI     v4l2_fourcc('I', 'N', 'Z', 'I') /* Intel Planar Greyscale 10-bit and Depth 16-bit */
+#define V4L2_PIX_FMT_MB32_NV12 v4l2_fourcc('M', 'N', '1', '2') /* Allwinner tiled NV12 format */
 
 /* 10bit raw bayer packed, 32 bytes for every 25 pixels, last LSB 6 bits unused */
 #define V4L2_PIX_FMT_IPU3_SBGGR10	v4l2_fourcc('i', 'p', '3', 'b') /* IPU3 packed 10-bit BGGR bayer */
-- 
2.18.0