linux-kernel - [PATCH 2/7] docs: uapi: media: Document Raspberry Pi NV12 column format

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20241220-media-rpi-hevc-dec-v1-2-0ebcc04ed42e@raspberrypi.com>
Date: Fri, 20 Dec 2024 16:21:13 +0000
From: Dave Stevenson <dave.stevenson@...pberrypi.com>
To: Sakari Ailus <sakari.ailus@...ux.intel.com>, 
 Laurent Pinchart <laurent.pinchart@...asonboard.com>, 
 Mauro Carvalho Chehab <mchehab@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, 
 Florian Fainelli <florian.fainelli@...adcom.com>, 
 Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>, 
 John Cox <john.cox@...pberrypi.com>, Dom Cobley <dom@...pberrypi.com>, 
 review list <kernel-list@...pberrypi.com>, 
 Ezequiel Garcia <ezequiel@...guardiasur.com.ar>
Cc: John Cox <jc@...esim.co.uk>, linux-media@...r.kernel.org, 
 linux-kernel@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-rpi-kernel@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org, 
 Dave Stevenson <dave.stevenson@...pberrypi.com>
Subject: [PATCH 2/7] docs: uapi: media: Document Raspberry Pi NV12 column
 format

The Raspberry Pi HEVC decoder uses a tiled format based on
columns for 8 and 10 bit YUV images, so document them as
NV12MT_COL128 and NV12MT_10_COL128.

Signed-off-by: Dave Stevenson <dave.stevenson@...pberrypi.com>
---
 .../userspace-api/media/v4l/pixfmt-yuv-planar.rst  | 42 ++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
index b788f6933855..90414491d7b5 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
@@ -827,6 +827,48 @@ Data in the 12 high bits, zeros in the 4 low bits, arranged in little endian ord
       - Cb\ :sub:`11`
       - Cr\ :sub:`11`
 
+NV12MT_COL128 and NV12MT_10_COL128
+----------------------------------
+
+``V4L2_PIX_FMT_NV12MT_COL128`` is a tiled version of
+``V4L2_PIX_FMT_NV12M`` where the two planes are split into 128 byte wide columns
+of Y or interleaved CbCr.
+
+NV12MT_10_COL128 expands that as a 10 bit format where 3 10 bit values are
+packed into a 32bit word. A 128 byte wide column therefore holds 96 samples
+(either Y or interleaved CrCb). That effectively makes it 6 values in a 64 bit
+word for the CbCr plane, as the values always go in pairs.
+
+Bit-packed representation.
+
+.. tabularcolumns:: |p{1.2cm}||p{1.2cm}||p{1.2cm}||p{1.2cm}|p{3.2cm}|p{3.2cm}|
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths: 8 8 8 8
+
+    * - Y'\ :sub:`00[7:0]`
+      - Y'\ :sub:`01[5:0] (bits 7--2)` Y'\ :sub:`00[9:8]`\ (bits 1--0)
+      - Y'\ :sub:`02[3:0] (bits 7--4)` Y'\ :sub:`01[9:6]`\ (bits 3--0)
+      - unused (bits 7--6)` Y'\ :sub:`02[9:4]`\ (bits 5--0)
+
+.. tabularcolumns:: |p{1.2cm}||p{1.2cm}||p{1.2cm}||p{1.2cm}|p{3.2cm}|p{3.2cm}|
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths: 12 12 12 12 12 12 12 12
+
+    * - Cb\ :sub:`00[7:0]`
+      - Cr\ :sub:`00[5:0]`\ (bits 7--2) Cb\ :sub:`00[9:8]`\ (bits 1--0)
+      - Cb\ :sub:`01[3:0]`\ (bits 7--4) Cr\ :sub:`00[9:6]`\ (bits 3--0)
+      - unused (bits 7--6) Cb\ :sub:`02[9:4]`\ (bits 5--0)
+      - Cr\ :sub:`01[7:0]`
+      - Cb\ :sub:`02[5:0]`\ (bits 7--2) Cr\ :sub:`01[9:8]`\ (bits 1--0)
+      - Cr\ :sub:`02[3:0]`\ (bits 7--4) Cb\ :sub:`02[9:6]`\ (bits 3--0)
+      - unused (bits 7--6) Cr\ :sub:`02[9:4]`\ (bits 5--0)
+
 
 Fully Planar YUV Formats
 ========================

-- 
2.34.1