On Wed, Jul 13, 2016 at 11:24:55AM +0000, Radhey Shyam Pandey wrote: > Hello All, > Pls wrap within 80 chars, I have reflown below > I am planning to write DMA driver for new Xilinx VDMA IP (HLS Based) and > integrate it with Xilinx V4L2 capture pipeline. It should be update on existing VDMA driver then? > > For single DMA read/write transaction hardware requires two physically > separate buffers for Y and CbCr components, which must be placed in two > different memory banks. i.e DMA reads YUV AXI-Stream for source(DEV) and > put it MEM into planar format. > > > V4L2_PIX_FMT_NV16 (Description) These are two-plane versions of the YUV > 4:2:2 format. The three components are separated into two sub-images or > planes. The Y plane is first. The Y plane has one byte per pixel. For > V4L2_PIX_FMT_NV16, a combined CbCr plane immediately follows the Y plane > in memory. The CbCr plane is the same width and height, in bytes, as the > Y plane (and of the image). > > So I need some attribute in struct dma_channel to indicate that it > supports packed/planar format? > > Also while programming DMA we need to provide the base address of Y plane > and UV plane to hardware for one DMA transaction. Current > dmaengine_prep_* implementations doesn't provide an interface to program > multiplanar channel address. Sounds like interleaved API could be used here? > > One way is to split programming of DMA channel into two > dma_async_tx_descriptor's for each channel (Y and UV) request but that > doesn't looks right. There will be two DMA/callbacks programming for a > single DMA write/read transaction. Any suggestions? Nope doesnt look right. A descriptor is for channel, splitting them causes all descriptor and cookie calculations and assumptions to go wrong > This email and any attachments are intended for the sole use of the named > recipient(s) and contain(s) confidential information that may be > proprietary, privileged or copyrighted under applicable law. If you are > not the intended recipient, do not read, copy, or forward this email > message or any attachments. Delete this email message and any attachments > immediately. pls fix this as well. -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
