R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express* Design Example User Guide

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ID 683544
Date 12/04/2023
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Document Table of Contents
Document Table of Contents x
1. About the R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express 2. Quick Start Guide 3. R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express* Design Example User Guide Archives 4. Document Revision History for the R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express* Design Example User Guide
1. About the R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express x
1.1. Functional Description for the Programmed Input/Output (PIO) Design Example 1.2. Functional Description for the Single Root I/O Virtualization (SR-IOV) Design Example 1.3. Functional Description for the Performance Design Example 1.4. Hardware and Software Requirements
1.1. Functional Description for the Programmed Input/Output (PIO) Design Example x
1.1.1. Credit Initialization Sequence
1.1.1. Credit Initialization Sequence x
1.1.1.1. Credit Value Initialization and Return 1.1.1.2. Credit Distribution
2. Quick Start Guide x
2.1. Directory Structure 2.2. Generating the Design Example 2.3. Simulating the Design Example 2.4. Root Port BFM 2.5. Compiling the Design Example 2.6. Installing the Linux Kernel Driver 2.7. Running the Design Example
2.3. Simulating the Design Example x
2.3.1. Steps to Run Simulations 2.3.2. Testbench
2.3.1. Steps to Run Simulations x
2.3.1.1. Siemens EDA QuestaSim* Simulator 2.3.1.2. VCS* Simulator 2.3.1.3. VCS* MX Simulator 2.3.1.4. Xcelium* Simulator
2.3.2. Testbench x
2.3.2.1. Testbench Modules 2.3.2.2. Test Driver Module 2.3.2.3. PIO Design Example Testbench 2.3.2.4. SR-IOV Design Example Testbench
2.4. Root Port BFM x
2.4.1. BFM Memory Map 2.4.2. Configuration Space Bus and Device Numbering 2.4.3. Configuration of Root Port and Endpoint 2.4.4. Issuing Read and Write Transactions to the Application Layer 2.4.5. BFM Procedures and Functions
2.4.5. BFM Procedures and Functions x
2.4.5.1. ebfm_barwr Procedure 2.4.5.2. ebfm_barwr_imm Procedure 2.4.5.3. ebfm_barrd_wait Procedure 2.4.5.4. ebfm_barrd_nowt Procedure 2.4.5.5. ebfm_cfgwr_imm_wait Procedure 2.4.5.6. ebfm_cfgwr_imm_nowt Procedure 2.4.5.7. ebfm_cfgrd_wait Procedure 2.4.5.8. ebfm_cfgrd_nowt Procedure 2.4.5.9. BFM Configuration Procedures 2.4.5.10. BFM Shared Memory Access Procedures 2.4.5.11. BFM Log and Message Procedures 2.4.5.12. Verilog HDL Formatting Functions
2.4.5.9. BFM Configuration Procedures x
2.4.5.9.1. ebfm_cfg_rp_ep Procedure 2.4.5.9.2. ebfm_cfg_decode_bar Procedure
2.4.5.10. BFM Shared Memory Access Procedures x
2.4.5.10.1. Shared Memory Constants 2.4.5.10.2. shmem_write Task 2.4.5.10.3. shmem_read Function 2.4.5.10.4. shmem_display Verilog HDL Function 2.4.5.10.5. shmem_fill Procedure 2.4.5.10.6. shmem_chk_ok Function
2.4.5.11. BFM Log and Message Procedures x
2.4.5.11.1. ebfm_display Verilog HDL Function 2.4.5.11.2. ebfm_log_stop_sim Verilog HDL Function 2.4.5.11.3. ebfm_log_set_suppressed_msg_mask Task 2.4.5.11.4. ebfm_log_set_stop_on_msg_mask Verilog HDL Task 2.4.5.11.5. ebfm_log_open Verilog HDL Function 2.4.5.11.6. ebfm_log_close Verilog HDL Function
2.4.5.12. Verilog HDL Formatting Functions x
2.4.5.12.1. himage1 2.4.5.12.2. himage2 2.4.5.12.3. himage4 2.4.5.12.4. himage8 2.4.5.12.5. himage16 2.4.5.12.6. dimage1 2.4.5.12.7. dimage2 2.4.5.12.8. dimage3 2.4.5.12.9. dimage4 2.4.5.12.10. dimage5 2.4.5.12.11. dimage6 2.4.5.12.12. dimage7
2.7. Running the Design Example x
2.7.1. Running the PIO Design Example 2.7.2. Running the SR-IOV Design Example 2.7.3. Running the Performance Design Example
1. About the R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express
2. Quick Start Guide
3. R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express* Design Example User Guide Archives
4. Document Revision History for the R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express* Design Example User Guide

1.1.1. Credit Initialization Sequence

In R-Tile, the back-pressure mechanism by the PIO component is done through the credit system. Therefore, the credit value must be declared during the credit initialization stage. An initial TX credit value is captured by the DUT and deducted for any TLP sent to the PIO. When the credit value reaches zero, the DUT stops sending any more TLP until the PIO returns the credit.

For the R-Tile design example, the RX_CRDT_INIT block interfaces with the credit signals from the DUT as shown in the figure below. The block focuses on initializing and returning the RX credit. In the TX direction, the block only asserts crdt_init_ack to complete the initialization stage. The PIO component captures the TX credit during the initialization stage initiated by the DUT.

Figure 6. Credit System of the Design Example

The waveforms below show the initialization sequence for RX credit from PIO to DUT. During the initialization phase, the PIO asserts the *crdt_init signal. In response, the DUT asserts the *crdt_init_ack signal. After receiving the ack signal, the PIO asserts *crdt_update and the internal crdt_cnt of the DUT captures the *crdt_update_cnt value.

Figure 7. Waveforms of Credit Transactions During the Initialization Stage

Section Content
Credit Value Initialization and Return
Credit Distribution

Level Two Title