Hi Hans,
On Friday 11 October 2013 01:16 PM, Hans Verkuil wrote:
On 10/09/2013 04:29 PM, Archit Taneja wrote:
VPE is a block which consists of a single memory to memory path which can
perform chrominance up/down sampling, de-interlacing, scaling, and color space
conversion of raster or tiled YUV420 coplanar, YUV422 coplanar or YUV422
interleaved video formats.
We create a mem2mem driver based primarily on the mem2mem-testdev example.
The de-interlacer, scaler and color space converter are all bypassed for now
to keep the driver simple. Chroma up/down sampler blocks are implemented, so
conversion beteen different YUV formats is possible.
Each mem2mem context allocates a buffer for VPE MMR values which it will use
when it gets access to the VPE HW via the mem2mem queue, it also allocates
a VPDMA descriptor list to which configuration and data descriptors are added.
Based on the information received via v4l2 ioctls for the source and
destination queues, the driver configures the values for the MMRs, and stores
them in the buffer. There are also some VPDMA parameters like frame start and
line mode which needs to be configured, these are configured by direct register
writes via the VPDMA helper functions.
The driver's device_run() mem2mem op will add each descriptor based on how the
source and destination queues are set up for the given ctx, once the list is
prepared, it's submitted to VPDMA, these descriptors when parsed by VPDMA will
upload MMR registers, start DMA of video buffers on the various input and output
clients/ports.
When the list is parsed completely(and the DMAs on all the output ports done),
an interrupt is generated which we use to notify that the source and destination
buffers are done.
The rest of the driver is quite similar to other mem2mem drivers, we use the
multiplane v4l2 ioctls as the HW support coplanar formats.
Signed-off-by: Archit Taneja <archit@xxxxxx>
Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Thanks for the Acks. Is it possible to queue these for 3.13?
Archit
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