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AR# 44700

AXI Bridge for PCI Express - C_PCIEBAR2AXIBAR_# restriction on bits lower than C_PCIBAR_LEN_#

Description

Version Found: 1.00.a
Version Resolved and other Known Issues: See (Xilinx Answer 44969)

The C_PCIEBAR2AXIBAR_# attribute describes the relationship between a BAR and the AXI memory mapped space.The address located at the BAR# registers in the configuration space is determined by the host during enumeration. The size of the BAR is determined by the C_PCIEBAR_LEN_# attribute. When a TLP is received, the address from the TLP is checked to see if it is within the BAR and BAR+2^C_PCIEBAR_LEN_#. This is determined to be a BAR hit.

Once a BAR hit is determined, the difference between the TLP address and the BAR is the offset.The offset is then appended to the C_PCIEBAR2AXIBAR_#[31:C_PCIEBAR_LEN_#] creating a total of a 32-bit range. Since C_PCIEBAR_LEN_# is a fixed value, the lower bits of C_PCIEBAR2AXIBAR_# might get stripped out depending on the value provided.

NOTE:The "Version Found" columnlists the version that the problem was firstdiscovered. The problem might also exist in earlier versions, but no specific testing has been performedto verify earlier versions.

Solution

The lower bits ofC_PCIEBAR2AXIBAR_# might not get used depending on the size that waschosen forC_PCIEBAR_LEN_#. You must ensure thatC_PCIEBAR2AXIBAR_# only uses the bits from [31:C_PCIEBAR_LEN_#]. Otherwise, the lower bits will be trimmed out when concatenating with the offset.

Revision History
11/21/2011 - Updated format
10/25/2011 - Initial Release

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
44969 AXI Bridge for PCI Express - Release Notes and Known Issues for All Versions up to ISE 14.7 N/A N/A

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
44969 AXI Bridge for PCI Express - Release Notes and Known Issues for All Versions up to ISE 14.7 N/A N/A
AR# 44700
Date Created 10/25/2011
Last Updated 05/22/2012
Status Active
Type Known Issues
IP
  • AXI PCI Express (PCIe)