Hello Laurent,
regarding your main question, I think the name "image renderer" is
misguiding. This IP-block has nothing to do with rendering per se, it is
rather an image processing module, designed specifically for image
undistortion (lens correction). We use that as a plain memory-to-memory
device, and it fits well into V4L2 framework. More complex
implementation (the one we thought of, but had no capacity to implement)
would allow integration of VIN (as well as other modules like
H.264/MPEG4 decoders) and IMR engines into a single processing pipeline
(so it would not look like a M2M device but would be a sort of
"smart-VIN"). From that perspective it is no more DRM device driver than
VSP, which resides in the same "drivers/platform/media" directory.
Sincerely,
Kostya
On 02/12/2017 06:51 PM, Laurent Pinchart wrote:
Hi Sergei,
(CC'ing the dri-evel mailing list)
Thank you for the patch.
On Saturday 11 Feb 2017 23:02:01 Sergei Shtylyov wrote:
From: Konstantin Kozhevnikov <Konstantin.Kozhevnikov@xxxxxxxxxxxxxxxxxx>
The image renderer light extended 4 (IMR-LX4) or the distortion correction
engine is a drawing processor with a simple instruction system capable of
referencing data on an external memory as 2D texture data and performing
texture mapping and drawing with respect to any shape that is split into
triangular objects.
This V4L2 memory-to-memory device driver only supports image renderer found
in the R-Car gen3 SoCs; the R-Car gen2 support can be added later...
Let's start with the main question : given that this is a rendering engine, it
looks like it should use the DRM subsystem.
[Sergei: merged 2 original patches, added the patch description, removed
unrelated parts, added the binding document, ported the driver to the
modern kernel, renamed the UAPI header file and the guard macros to match
the driver name, extended the copyrights, fixed up Kconfig prompt/depends/
help, made use of the BIT()/GENMASK() macros, sorted #include's, removed
leading dots and fixed grammar in the comments, fixed up indentation to
use tabs where possible, renamed IMR_DLSR to IMR_DLPR to match the manual,
separated the register offset/bit #define's, removed *inline* from .c file,
fixed lines over 80 columns, removed useless parens, operators, casts,
braces, variables, #include's, (commented out) statements, and even
function, inserted empty line after desclaration, removed extra empty
lines, reordered some local variable desclarations, removed calls to
4l2_err() on kmalloc() failure, fixed the error returned by imr_default(),
avoided code duplication in the IRQ handler, used '__packed' for the UAPI
structures, enclosed the macro parameters in parens, exchanged the values
of IMR_MAP_AUTO[SD]G macros.]
Signed-off-by: Konstantin Kozhevnikov
<Konstantin.Kozhevnikov@xxxxxxxxxxxxxxxxxx> Signed-off-by: Sergei Shtylyov
<sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
---
This patch is against the 'media_tree.git' repo's 'master' branch.
Documentation/devicetree/bindings/media/rcar_imr.txt | 23
drivers/media/platform/Kconfig | 13
drivers/media/platform/Makefile | 1
drivers/media/platform/rcar_imr.c | 1923 +++++++++++++++
include/uapi/linux/rcar_imr.h | 94
5 files changed, 2054 insertions(+)
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