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> Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
