Ping! > -----Original Message----- > From: Radhey Shyam Pandey > Sent: Wednesday, July 13, 2016 4:55 PM > To: 'dmaengine@xxxxxxxxxxxxxxx' <dmaengine@xxxxxxxxxxxxxxx> > Cc: Hyun Kwon <hyunk@xxxxxxxxxx>; Kedareswara rao Appana > (appana.durga.rao@xxxxxxxxxx) <appana.durga.rao@xxxxxxxxxx>; Laurent > Pinchart (laurent.pinchart@xxxxxxxxxxxxxxxx) > <laurent.pinchart@xxxxxxxxxxxxxxxx>; nofooter <nofooter@xxxxxxxxxx> > Subject: DMA Engine API multiplanar support > > Hello All, > > I am planning to write DMA driver for new Xilinx VDMA IP (HLS Based) and > integrate it with Xilinx V4L2 capture pipeline. > > 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. > > 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? > > Thanks, > Radhey 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. -- 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
