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1. Introduction
2. Quick Start Guide
3. Interface Overview
4. Parameters
5. Designing with the IP Core
6. Block Descriptions
7. Interrupts
8. Registers
9. Testbench and Design Example
10. Troubleshooting and Observing the Link
A. PCI Express Core Architecture
B. TX Credit Adjustment Sample Code
C. Root Port Enumeration
D. Document Revision History
1.1. Avalon-ST Interface with Optional SR-IOV for PCIe Introduction
1.2. Features
1.3. Release Information
1.4. Device Family Support
1.5. Recommended Fabric Speed Grades
1.6. Performance and Resource Utilization
1.7. Transceiver Tiles
1.8. PCI Express IP Core Package Layout
1.9. Channel Availability
2.1. Design Components
2.2. Hardware and Software Requirements
2.3. Directory Structure
2.4. Generating the Design Example
2.5. Simulating the Design Example
2.6. Compiling the Design Example and Programming the Device
2.7. Installing the Linux Kernel Driver
2.8. Running the Design Example Application
3.1. Avalon-ST RX Interface
3.2. Avalon-ST TX Interface
3.3. TX Credit Interface
3.4. TX and RX Serial Data
3.5. Clocks
3.6. Function-Level Reset (FLR) Interface
3.7. Control Shadow Interface for SR-IOV
3.8. Configuration Extension Bus Interface
3.9. Hard IP Reconfiguration Interface
3.10. Interrupt Interfaces
3.11. Power Management Interface
3.12. Reset
3.13. Transaction Layer Configuration Interface
3.14. PLL Reconfiguration Interface
3.15. PIPE Interface (Simulation Only)
4.1. Stratix 10 Avalon-ST Settings
4.2. Multifunction and SR-IOV System Settings
4.3. Base Address Registers
4.4. Device Identification Registers
4.5. TPH/ATS Capabilities
4.6. PCI Express and PCI Capabilities Parameters
4.7. Configuration, Debug and Extension Options
4.8. PHY Characteristics
4.9. Example Designs
6.1.1. TLP Header and Data Alignment for the Avalon-ST RX and TX Interfaces
6.1.2. Avalon-ST 256-Bit RX Interface
6.1.3. Avalon-ST 512-Bit RX Interface
6.1.4. Avalon-ST 256-Bit TX Interface
6.1.5. Avalon-ST 512-Bit TX Interface
6.1.6. TX Credit Interface
6.1.7. Interpreting the TX Credit Interface
6.1.8. Clocks
6.1.9. Update Flow Control Timer and Credit Release
6.1.10. Function-Level Reset (FLR) Interface
6.1.11. Resets
6.1.12. Interrupts
6.1.13. Control Shadow Interface for SR-IOV
6.1.14. Transaction Layer Configuration Space Interface
6.1.15. Configuration Extension Bus Interface
6.1.16. Hard IP Status Interface
6.1.17. Hard IP Reconfiguration
6.1.18. Power Management Interface
6.1.19. Serial Data Interface
6.1.20. PIPE Interface
6.1.21. Test Interface
6.1.22. PLL IP Reconfiguration
6.1.23. Message Handling
8.1.1. Register Access Definitions
8.1.2. PCI Configuration Header Registers
8.1.3. PCI Express Capability Structures
8.1.4. Intel Defined VSEC Capability Header
8.1.5. General Purpose Control and Status Register
8.1.6. Uncorrectable Internal Error Status Register
8.1.7. Uncorrectable Internal Error Mask Register
8.1.8. Correctable Internal Error Status Register
8.1.9. Correctable Internal Error Mask Register
8.1.10. SR-IOV Virtualization Extended Capabilities Registers Address Map
8.1.10.1. ARI Enhanced Capability Header
8.1.10.2. SR-IOV Enhanced Capability Registers
8.1.10.3. Initial VFs and Total VFs Registers
8.1.10.4. VF Device ID Register
8.1.10.5. Page Size Registers
8.1.10.6. VF Base Address Registers (BARs) 0-5
8.1.10.7. Secondary PCI Express Extended Capability Header
8.1.10.8. Lane Status Registers
8.1.10.9. Transaction Processing Hints (TPH) Requester Enhanced Capability Header
8.1.10.10. TPH Requester Capability Register
8.1.10.11. TPH Requester Control Register
8.1.10.12. Address Translation Services ATS Enhanced Capability Header
8.1.10.13. ATS Capability Register and ATS Control Register
9.4.1. ebfm_barwr Procedure
9.4.2. ebfm_barwr_imm Procedure
9.4.3. ebfm_barrd_wait Procedure
9.4.4. ebfm_barrd_nowt Procedure
9.4.5. ebfm_cfgwr_imm_wait Procedure
9.4.6. ebfm_cfgwr_imm_nowt Procedure
9.4.7. ebfm_cfgrd_wait Procedure
9.4.8. ebfm_cfgrd_nowt Procedure
9.4.9. BFM Configuration Procedures
9.4.10. BFM Shared Memory Access Procedures
9.4.11. BFM Log and Message Procedures
9.4.12. Verilog HDL Formatting Functions
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B. TX Credit Adjustment Sample Code
This sample Verilog HDL code computes the available credits for non-posted TLPs. It provides the updated credit information from the remote device on the tx_nph_cdts and tx_npd_cdts buses. The tx_nph_cdts and tx_npd_cdts buses drive the actual available credit space in the link partner's RX buffer. The credit information contained in these buses is difficult to use because, due to the EMIB (Embedded Multi-die Interconnect Bridge) latency, the values that you can observe on these buses are not real-time values.
The following Verilog RTL restores the credit limit for non-posted TLPs that can be used by application logic before it sends a TLP.
module nph_credit_limit_gen ( input clk, input rst_n, input [7:0] tx_nph_cdts, input tx_hdr_cdts_consumed, input [1:0] tx_cdts_type, output [7:0] tx_nph_cdts_limit ); reg tx_nph_credit_consume_1r; reg tx_nph_credit_consume_2r; reg [7:0] tx_nph_credit_consume_count_hip_3r; always @(posedge clk) begin if (!rst_n) begin tx_nph_credit_consume_1r <= 1'b0; tx_nph_credit_consume_2r <= 1'b0; tx_nph_credit_consume_count_hip <= 8'h0; end else begin tx_nph_credit_consume_1r <= (tx_cdts_type == 2'b01) ? tx_hdr_cdts_consumed : 1'b0; tx_nph_credit_consume_2r <= tx_nph_credit_consume_1r; tx_nph_credit_consume_count_hip_3r <= tx_nph_credit_consume_count_hip_3r + tx_nph_credit_consume_2r; end end assign tx_nph_cdts_limit = tx_nph_cdts + tx_nph_credit_consume_count_hip_3r; endmodule
The following pseudo-code explains the Verilog RTL above.
// reset credit_consume_count initially tx_nph_credit_consume_count = 0; tx_nph_credit_consume_count_hip = 0; if (tx_nph_credit_limit_count – (tx_nph_credit_consume_count + tx_nph_credit_required) <= (2^8)/2) { send NPH packet tx_nph_credit_consume_count += tx_nph_credit_required; } where tx_nph_credit_required: the number of credits required to send given NP TLP. For NP, tx_nph_credit_required is 1. tx_nph_credit_consume_count_hip += (tx_cdts_type == "01") ? tx_hdr_cdts_consumed : 1'b0; tx_nph_credit_consume_count_hip_delayed : three pld_clk cycle delayed tx_nph_credit_consume_count_hip tx_nph_credit_limit_count = tx_nph_cdts + tx_nph_credit_consume_count_hip_delayed;