4.4.1 Running DMA Operations

When the Root Port initiates the DMA operation, the Mi-V soft processor activates the Endpoint DMA registers through BAR0. The Endpoint DMA engines can perform the following DMA operations:

  • Root Port LSRAM/DDR4 to Endpoint LSRAM\DDR3\DDR4
  • Endpoint LSRAM\DDR3\DDR4 to Root Port LSRAM\DDR4

To run the DMA operations, perform the following steps:

  1. Click DMA Operations tab, as shown in Figure 4-14.
  2. Do the following:
    • Select the RP LSRAM -> EP LSRAM from the drop-down list.
    • Select 64K from the Transfer Size (Bytes) drop-down.
    • Set the Loop Count to 20 (Transfer Size and Loop Count are common parameters that can be adjusted).
    • Click Start transfer.
      Figure 4-14. Initiating RP LSRAM to EP LSRAM DMA

    The GUI displays the corresponding throughput details and graph, as shown in the following figure.

    Figure 4-15. RP LSRAM to EP LSRAM Throughput
  3. Do the following to initiate another DMA transaction:
    • Select Both RP LSRAM <-> EP LSRAM from the drop-down list.
    • Select 64K from the Transfer Size (Bytes) drop-down.
    • Set the Loop Count to 20 (Transfer Size and Loop Count are common parameters that can be adjusted).
    • Click Start Transfer.
  4. Similarly, select the RP LSRAM to EP DDR3 and RP LSRAM to EP DDR4 from the drop-down and observe the throughputs.
  5. Select DDR4 as the Root Port Memory Type and perform DMA operations by selecting the Endpoint destination memory type.