GTS AXI Streaming Intel® FPGA IP for PCI Express* User Guide

ID 813754
Date 8/07/2024
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

7.4.1. Configuration Intercept Request Interface

The application logic detects the CFG request at the assertion of p0_ss_app_st_ciireq_tvalid on the Configuration Intercept Request Interface and uses the interface to:
  • Delay the processing of a CFG request by the controller. This allows the application to perform any housekeeping task first. This can be achieved by withholding the assertion of p0_app_ss_st_ciireq_tready.
  • Overwrite the data payload of a configuration write request. The application logic also overwrites the data payload of a configuration read completion TLP. This can be achieved by using the Configuration Intercept Response Interface.
Table 43.  Configuration Intercept Request Interfacen = 0 or 1, p0 = port 0, and p1 = port 1
Note: Port 1 is only available in D-Series FPGAs
Signal Name Direction Endpoint (EP)/Root Port (RP)/TLP Bypass (BP) Clock Domain Description
p<n>_ss_app_st_ciireq_tvalid Output EP p<n>_axi_lite_clk

When asserted, indicates a valid CFG request cycle is waiting to be intercepted. Deasserted when p<n>_app_ss_st_ciireq_tready is asserted.

p<n>_app_ss_st_cciireq_tready Input EP p<n>_axi_lite_clk

The application asserts this signal for one clock to acknowledge p<n>_ss_app_st_ciireq_tvalid is seen by responder.

p<n>_ss_app_st_ciireq_tdata[71:0]

Output EP p<n>_axi_lite_clk
  • Bit [0]: The poisoned bit in the received TLP header on the CII.
  • Bit [4:1]: The first dword byte enable field in the received TLP header on the CII.
  • Bit [9:5]: Reserved.
  • Bit [12:10]: The PF number in the received TLP header on the CII.
  • Bit [23:13]: The child VF number of parent PF in the received TLP header on the CII.
  • Bit [24]: Indicates VF number is valid in the received TLP header on the CII.
  • Bit [25]: Indicates a configuration write request detected in the received TLP header on the CII. Also indicates that p<n>_ss_app_st_ciireq_tdata[67:36] is valid.
  • Bit [35:26]: The double word register address in the received TLP header on the CII.
  • Bit [67:36]: Received TLP payload data from the link partner to your application client. The data is in little endian format. The first received payload byte is in [43:36].
  • Bit [71:68]: Reserved.

The figure below shows the timing diagram for configuration write request indication to the application when the intercept feature is not enabled.

The first command is a config write to PF1 byte-1 and byte-0 at address = 0x200. The p<n>_ss_app_st_ciireq_tvalid is high for 1 clock cycle as the application is ready to accept the packet.

The second command is a full dword config write to VF=26 of PF5 at address = 0x3F0. As the application is not ready to accept the packet, the GTS AXI Streaming Intel® FPGA IP for PCI Express* holds the information until p<n>_app_ss_st_cciireq_tready is seen.

Figure 54. Configuration Intercept Request Interface