media: venus: implementing multi-stream support

media: venus: implementing multi-stream support

This is implementing multi-stream decoder support. The multi-stream
will be used to enable/disable the primary/secondary decoder
outputs. Depending on formats on both decoder outputs we could
implement downscale, dithering and supporting UBWC (universal
bandwidth compression) formats. The UBWC compressed raw format is
used to optimize interconnect bandwidth for bigger resolutions
like 4K and hence we will get some power-saving benefits as well.

Both decoder outputs are distinguished by buffer_type field in
the HFI packets. For example HFI_BUFFER_OUTPUT is the buffer type
for primary decoder output and HFI_BUFFER_OUTPUT2 is for secondary
decoder output.

Starting from Venus 4xx the DPB buffers format must be UBWC, so
the multi-stream becomes mandatory for this Venus version. That
means that we need to allocate internally in the driver a set of
DPB buffers (with UBWC NV12 format) and give them to the firmware.
The other decoder output (we called it OPB) format will be NV12
linear format and with the same resolution (or smaller in case
the user wants to downscale).

The DPB buffers are used for decoder reference frames and those
have to be in a specific format (UBWC). So one decoder output is
used to fill those reference buffers while the other output is
used to fill the userspace buffers with the user requested format.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Reviewed-by: Alexandre Courbot <acourbot@chromium.org>
Tested-by: Alexandre Courbot <acourbot@chromium.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>