Example 3 - 3.0 English

Versal ACAP CPM DMA and Bridge Mode for PCI Express Product Guide (PG347)

Document ID
PG347
Release Date
2022-06-15
Version
3.0 English

This example shows the generic settings to set up two independent BARs for PCIe® and address translation of addresses for PCIe to a remote AXI address space. This setting of BARs for PCIe does not depend on the AXI BARs within the bridge.

In this example, number of PCIe BAR are 2, the following range assignments are made.

AXI_ADDR_WIDTH=48

BAR 0 is set to 0x20000000_ABCD8000 by the Root Port. (Since this is a 64-bit BAR 
PCIe, BAR1 is disabled.)
PF0_BAR0_APERTURE_SIZE=0x08 (32 Kbytes)
PCIe to AXI Translation=0x00000000_12340000 (Because the AXI address is 48-bits wide, 
bits 63-48 should be zero. Base on the PCIe Bar Size bits 14-0 should be zero. 
Non-zero values in these ranges are invalid.)
BAR 2 is set to 0xA000000012000000 by Root Port. (Since this is a 64-bit
BAR PCIe BAR3
is disabled.)
SIZE=0x12 (32 Mbytes)
PCIe to AXI Translation = 0x00000000_FE000000 (Because the AXI address is 48-bits
wide, bits 63-48 should be zero. Based on the PCIe Bar Size bits 24-0 should be
zero. Non-zero values in these ranges are invalid.)
Figure 1. Example 3 Settings
  • Accessing the Bridge AXI BAR_0 with address 0x20000000_ABCDFFF4 on the bus for PCIe yields 0x0000_12347FF4 on the AXI bus.
Figure 2. PCIe to AXI Translation

  • Accessing Bridge AXI BAR_2 with address 0xA00000001235FEDC on the bus for PCIe yields 0x0000_FE35FEDC on the AXI bus.