AXI ID Management

AXI slave write requests are split transactions; that is, the client can make additional read and write requests while the response for a write request is pending. The client can issue each outstanding write requests with the same MASTER_AXI_AWID or unique ones. The PCIe Controller can receive a maximum of 32 outstanding write requests. For non-posted writes, the PCIe Controller internally maps the MASTER_AXI_AWID to an internally generated PCIe tag. It looks up this mapping to translate an incoming completion to a corresponding MASTER_AXI_BID value sent with the write response channel.