3. Memory Map and Address Spaces
- DMA view
- Host view
- DMA Descriptor view
The DMA view supports a 49-bit address space. The lower half of the DMA view maps to the local FPGA memory. Only the streaming DMA BBBs have connectivity to the local FPGA memory, the host cannot access the local FPGA memory. The upper half of the DMA view maps to host memory.
The host view includes all the registers accessible through MMIO accesses such as DFH table, and control/status registers of the various components that are used inside the streaming DMA AFU.
The DMA Descriptor view is a 48-bit address space that maps to the host memory. Because the DMA Fetch engine only accesses the host memory, it sees host memory at address 0x00 unlike the DMA view.
The MMIO registers in both streaming DMA BBBs and the streaming DMA AFU support 32- and 64-bit access. The streaming DMA AFU does not support 512-bit MMIO accesses. The dispatcher registers inside each streaming DMA BBB must be accessed using 32-bit accesses.
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