The following tables are the translation tables for AXI4-Stream and memory-mapped transactions.
| AXI4 Memory-Mapped Transaction | AXI4-Stream PCIe TLPs |
|---|---|
| INCR Burst Read of AXIBAR | MemRd 32 (3DW) |
| INCR Burst Write to AXIBAR | MemWr 32 (3DW) |
| INCR Burst Read of AXIBAR | MemRd 64 (4DW) |
| INCR Burst Write to AXIBAR | MemWr 64 (4DW) |
| AXI4-Stream PCIe TLPs | AXI4 Memory-Mapped Transaction |
|---|---|
| MemRd 32 (3DW) of PCIEBAR | INCR Burst Read |
| MemWr 32 (3DW) to PCIEBAR | INCR Burst Write |
| MemRd 64 (4DW) of PCIEBAR | INCR Burst Read |
| MemWr 64 (4DW) to PCIEBAR | INCR Burst Write |
For PCIe® requests with lengths greater than 1 Dword, the size of the data burst on the Master AXI interface will always equal the width of the AXI data bus even when the request received from the PCIe link is shorter than the AXI bus width.
slave axi wstrb can be used to
facilitate data alignment to an address boundary. slave axi
wstrb may equal 0 in the beginning of a valid data cycle and will
appropriately calculate an offset to the given address. However, the valid data
identified by slave axi wstrb must be continuous
from the first byte enable to the last byte enable.
All transactions initiated at the Slave Bridge interface will be modified and metered by the IP as necessary. The Slave Bridge interface will conform to AXI4 specification and allow burst size up to 4KB, and the IP will split the transaction automatically according to PCIe Max Read Request Size (MRRS), Max Payload Size (MPS), and Read Completion Boundary (RCB), As a result of this operation, one request at the AXI domain may result in multiple request at the PCIe domain, and the IP will adjust the number of issued PCIe request accordingly to avoid oversubscribing the available Completion buffer.