220.127.116.11.4. Using the DMA Controller
To initiate a single DMA transfer, you only need to write a well-formed descriptor to one of the DMA Controller's descriptor queues (WDN, WDP, RDN or RDP).
To initiate a series of DMA transfers, you can prepare a table of descriptors padded to 512 bits each in a memory location accessible to the Read Data Mover. You can then write a single descriptor to the DMA Controller's priority descriptor queue (RDP) register to initiate the DMA transfers. These transfers move the descriptors from the source location in PCIe memory to the desired descriptor queue register.
To transmit an MSI interrupt upon completion of the processing of a descriptor, you must program the DMA Controller's WI or RI register with the desired MSI address and message before writing the descriptor.