P-Tile Avalon® Streaming Intel® FPGA IP for PCI Express* User Guide

ID 683059
Date 3/28/2022
Public

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6.3.4. Issuing Read and Write Transactions to the Application Layer

The Root Port Application Layer issues read and write transactions by calling one of the ebfm_bar procedures in altpcietb_g3bfm_rdwr.v. The procedures and functions listed below are available in the Verilog HDL include file altpcietb_g3bfm_rdwr.v. The complete list of available procedures and functions is as follows:

  • ebfm_barwr: writes data from BFM shared memory to an offset from a specific Endpoint BAR. This procedure returns as soon as the request has been passed to the VC interface module for transmission.
  • ebfm_barwr_imm: writes a maximum of four bytes of immediate data (passed in a procedure call) to an offset from a specific Endpoint BAR. This procedure returns as soon as the request has been passed to the VC interface module for transmission.
  • ebfm_barrd_wait: reads data from an offset of a specific Endpoint BAR and stores it in BFM shared memory. This procedure blocks waiting for the completion data to be returned before returning control to the caller.
  • ebfm_barrd_nowt: reads data from an offset of a specific Endpoint BAR and stores it in the BFM shared memory. This procedure returns as soon as the request has been passed to the VC interface module for transmission, allowing subsequent reads to be issued in the interim.

These routines take as parameters a BAR number to access the memory space and the BFM shared memory address of the bar_table data structure that was set up by the ebfm_cfg_rp_ep procedure. (Refer to Configuration of Root Port and Endpoint.) Using these parameters simplifies the BFM test driver routines that access an offset from a specific BAR and eliminates calculating the addresses assigned to the specified BAR.

The Root Port BFM does not support accesses to Endpoint I/O space BARs.

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