[PATCH v5 2/2] Documentation/gpu: Add Synaptics tiling formats documentation

[Hsia-Jun Li]

From: Randy Li <ayaka at soulik.info>

Signed-off-by: Randy Li <ayaka at soulik.info>
Signed-off-by: Hsia-Jun(Randy) Li <randy.li at synaptics.com>
---
 Documentation/gpu/drivers.rst   |   1 +
 Documentation/gpu/synaptics.rst | 104 ++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+)
 create mode 100644 Documentation/gpu/synaptics.rst

diff --git a/Documentation/gpu/drivers.rst b/Documentation/gpu/drivers.rst
index 3a52f48215a3..7e820c93d994 100644
--- a/Documentation/gpu/drivers.rst
+++ b/Documentation/gpu/drivers.rst
@@ -18,6 +18,7 @@ GPU Driver Documentation
    xen-front
    afbc
    komeda-kms
+   synaptics
 
 .. only::  subproject and html
 
diff --git a/Documentation/gpu/synaptics.rst b/Documentation/gpu/synaptics.rst
new file mode 100644
index 000000000000..b0564d2fe3ce
--- /dev/null
+++ b/Documentation/gpu/synaptics.rst
@@ -0,0 +1,104 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+
+================
+Synaptics Tiling
+================
+
+The tiling pixel formats in Synpatics Video Smart platform have
+many variants. Tiles could form the group of tiles(GOT), pixels
+within a group rectangle are stored into tile.
+There are two parameters which consist a modifier described
+the (nearest) width and height pixels in a group.
+
+Meanwhile, the tile in a group may not follow dimension
+layout, tile could form a small group of tiles, then that (sub)group
+of tiles would form a bigger group. We won't describe the dimension
+layout inside the group of tiles here. The layout of the group
+of tiles is fixed with the group width and height parameters
+in the same generation of the platform.
+
+Compression
+===========
+The proprietary lossless image compression protocol in Synaptics
+could minimizes the amount of data transferred (less memory bandwidth
+consumption) between devices. It would usually apply to the tiling
+pixel format.
+
+Each component would request an extra page aligned length buffer
+for storing the compression meta data. Also a 32 bytes parameters
+set would come with a compression meta data buffer.
+
+The component here corresponds to a signal type (i.e. Luma, Chroma).
+They could be encoded into one or multiple metadata planes, but
+their compression parameters would still be individual.
+
+Pixel format modifiers
+======================
+Addition alignment requirement for stride and size of a memory plane
+could apply beyond what has been mentioned below. Remember always
+negotiating with all the devices in pipeline before allocation.
+
+.. raw:: latex
+
+    \small
+
+.. tabularcolumns:: |p{5.8cm}|p{1.2cm}|p{10.3cm}|
+
+.. cssclass:: longtable
+
+.. flat-table:: Synpatics Image Format Modifiers
+    :header-rows:  1
+    :stub-columns: 0
+    :widths:       3 1 8
+
+    * - Identifier
+      - Fourcc
+      - Details
+    * .. _DRM-FORMAT-MOD-SYNA-V4H1
+
+      - ``DRM_FORMAT_MOD_SYNA_V4H1``
+      - ``DRM_FORMAT_NV12``
+      - The plain uncompressed 8 bits tile format. It sounds similar to
+	Intel's Y-tile. but it won't take any pixel from the next X direction
+	in a tile group. The line stride and image height must be aligned to
+	a multiple of 16. The height of chrominance plane would plus 8.
+    * .. _DRM-FORMAT-MOD-SYNA-V4H3P8
+
+      - ``DRM_FORMAT_MOD_SYNA_V4H3P8``
+      - ``DRM_FORMAT_NV15``
+      - The plain uncompressed 10 bits tile format. It stores pixel in 2D
+	3x4 tiles with a 8bits padding to each of tile. Then a tile is in a
+	128 bits cache line.
+    * .. _DRM-FORMAT-MOD-SYNA-V4H1-64L4-COMPRESSED
+
+      - ``DRM_FORMAT_MOD_SYNA_V4H1_64L4_COMPRESSED``
+      - ``DRM_FORMAT_NV12``
+      - Group of tiles and compressed variant of ``DRM_FORMAT_MOD_SYNA_V4H1``.
+	A group of tiles would contain 64x4 pixels, where a tile has 1x4
+	pixel.
+    * .. _DRM-FORMAT-MOD-SYNA-V4H3P8-64L4-COMPRESSED
+
+      - ``DRM_FORMAT_MOD_SYNA_V4H3P8_64L4_COMPRESSED``
+      - ``DRM_FORMAT_NV15``
+      - Group of tiles and compressed variant of ``DRM_FORMAT_MOD_SYNA_V4H3P8``.
+	A group of tiles would contains 48x4 pixels, where a tile has 3x4 pixels
+	and a 8 bits padding in the end of a tile. A group of tiles would
+	be 256 bytes.
+    * .. _DRM-FORMAT-MOD-SYNA-V4H1-128L128-COMPRESSED
+
+      - ``DRM_FORMAT_MOD_SYNA_V4H1_128L128_COMPRESSED``
+      - ``DRM_FORMAT_NV12``
+      - Group of tiles and compressed variant of ``DRM_FORMAT_MOD_SYNA_V4H1``.
+	A group of tiles would contain 128x32 pixels, where a tile has 1x4 pixel.
+    * .. _DRM-FORMAT-MOD-SYNA-V4H3P8-128L128-COMPRESSED
+
+      - ``DRM_FORMAT_MOD_SYNA_V4H3P8_128L128_COMPRESSED``
+      - ``DRM_FORMAT_NV15``
+      - Group of tiles and compressed variant of ``DRM_FORMAT_MOD_SYNA_V4H3P8``.
+	A group of tiles would contains 96x128 pixels, where a tile has 3x4 pixels
+	and a 8 bits padding in the end of a tile. A group of tiles would 
+	be 16 KiB.
+
+.. raw:: latex
+
+    \normalsize
-- 
2.37.3