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

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ID 683501
Date 10/07/2022
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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. IP Architecture and Functional Description 3. Advanced Features 4. Interfaces 5. Parameters 6. Troubleshooting/Debugging 7. R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express* User Guide Archives 8. Document Revision History for the R-Tile Avalon® Streaming Intel FPGA IP for PCI Express User Guide A. Configuration Space Registers B. Root Port Enumeration C. Implementation of Address Translation Services (ATS) in Endpoint Mode D. Packets Forwarded to the User Application in TLP Bypass Mode
1. About the R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express x
1.1. Overview 1.2. Features 1.3. Release Information 1.4. Device Family Support 1.5. Performance and Resource Utilization 1.6. IP Core Support Levels
1.1. Overview x
1.1.1. Standards and Specifications Compliance
1.2. Features x
1.2.1. Multifunction and Virtualization Features
2. IP Architecture and Functional Description x
2.1. Overview 2.2. Bias Temperature Instability (BTI) Protection Mode 2.3. PCIe Hard IP Mode 2.4. PIPE Direct Mode
2.3. PCIe Hard IP Mode x
2.3.1. Clocking 2.3.2. Reset 2.3.3. PCI Express Protocol Stack
2.3.2. Reset x
2.3.2.1. Single PERST 2.3.2.2. Independent PERST
2.3.2.2. Independent PERST x
2.3.2.2.1. REFCLK and PERST Guidelines when Using Independent PERST
2.3.3. PCI Express Protocol Stack x
2.3.3.1. PMA/PCS 2.3.3.2. Data Link Layer Overview 2.3.3.3. Transaction Layer Overview
2.3.3.3. Transaction Layer Overview x
2.3.3.3.1. Deferrable Memory Write (DMWr)
2.4. PIPE Direct Mode x
2.4.1. Clocking 2.4.2. Reset 2.4.3. PIPE Layer
3. Advanced Features x
3.1. PCIe Port Bifurcation and PHY Channel Mapping 3.2. Virtualization Support 3.3. TLP Bypass Mode
3.2. Virtualization Support x
3.2.1. SR-IOV Support 3.2.2. VirtIO Support
3.2.1. SR-IOV Support x
3.2.1.1. SR-IOV Supported Features List 3.2.1.2. Implementation 3.2.1.3. VF to PF Mapping 3.2.1.4. Function Level Reset (FLR)
3.2.1.2. Implementation x
3.2.1.2.1. VF Error Flag Interface (for x16/x8 Cores Only)
3.2.2. VirtIO Support x
3.2.2.1. VirtIO Supported Features List 3.2.2.2. Overview 3.2.2.3. Parameters 3.2.2.4. VirtIO PCI Configuration Access Interface 3.2.2.5. Registers
3.2.2.5. Registers x
3.2.2.5.1. VirtIO Common Configuration Capability Register (Address: 0x012) 3.2.2.5.2. VirtIO Common Configuration BAR Indicator Register (Address: 0x013) 3.2.2.5.3. VirtIO Common Configuration BAR Offset Register (Address: 0x014) 3.2.2.5.4. VirtIO Common Configuration Structure Length Register (Address 0x015) 3.2.2.5.5. VirtIO Notifications Capability Register (Address: 0x016) 3.2.2.5.6. VirtIO Notifications BAR Indicator Register (Address: 0x017) 3.2.2.5.7. VirtIO Notifications BAR Offset Register (Address: 0x018) 3.2.2.5.8. VirtIO Notifications Structure Length Register (Address: 0x019) 3.2.2.5.9. VirtIO Notifications Notify Off Multiplier Register (Address: 0x01A) 3.2.2.5.10. VirtIO ISR Status Capability Register (Address: 0x02F) 3.2.2.5.11. VirtIO ISR Status BAR Indicator Register (Address: 0x030) 3.2.2.5.12. VirtIO ISR Status BAR Offset Register (Address: 0x031) 3.2.2.5.13. VirtIO ISR Status Structure Length Register (Address: 0x032) 3.2.2.5.14. VirtIO Device Specific Capability Register (Address: 0x033) 3.2.2.5.15. VirtIO Device Specific BAR Indicator Register (Address: 0x034) 3.2.2.5.16. VirtIO Device Specific BAR Offset Register (Address 0x035) 3.2.2.5.17. VirtIO Device Specific Structure Length Register (Address: 0x036) 3.2.2.5.18. VirtIO PCI Configuration Access Capability Register (Address: 0x037) 3.2.2.5.19. VirtIO PCI Configuration Access BAR Indicator Register (Address: 0x038) 3.2.2.5.20. VirtIO PCI Configuration Access BAR Offset Register (Address: 0x039) 3.2.2.5.21. VirtIO PCI Configuration Access Structure Length Register (Address: 0x03A) 3.2.2.5.22. VirtIO PCI Configuration Access Data Register (Address: 0x03B)
3.3. TLP Bypass Mode x
3.3.1. Overview 3.3.2. Register Settings for the TLP Bypass Mode 3.3.3. Hard IP Reconfiguration Interface 3.3.4. Avalon® Streaming Interface
3.3.2. Register Settings for the TLP Bypass Mode x
3.3.2.1. TLPBYPASS_ERR_EN (Address 0x1314) 3.3.2.2. TLPBYPASS_ERR_STATUS (Address 0x1310)
3.3.4. Avalon® Streaming Interface x
3.3.4.1. Configuration TLP 3.3.4.2. Transmit Interface 3.3.4.3. Receive Interface 3.3.4.4. Malformed TLP 3.3.4.5. ECRC
4. Interfaces x
4.1. Clocks and Resets 4.2. Serial Data Interface 4.3. PCI Express Mode 4.4. PIPE Direct Mode
4.1. Clocks and Resets x
4.1.1. Clocks 4.1.2. Resets
4.3. PCI Express Mode x
4.3.1. Avalon® Streaming Interface 4.3.2. Precision Time Measurement (PTM) Interface (Endpoint Only) 4.3.3. Interrupt Interface 4.3.4. Hard IP Reconfiguration Interface 4.3.5. Error Interface 4.3.6. Completion Timeout Interface 4.3.7. Configuration Intercept Interface 4.3.8. Power Management Interface 4.3.9. Hard IP Status Interface 4.3.10. Page Request Services (PRS) Interface (Endpoint Only) 4.3.11. Function-Level Reset (FLR) Interface (Endpoint Only) 4.3.12. SR-IOV VF Error Flag Interface (Endpoint Only) 4.3.13. General Purpose VSEC Interface
4.3.1. Avalon® Streaming Interface x
4.3.1.1. TLP Header and Data Alignment for the Avalon® streaming RX and TX Interfaces 4.3.1.2. Credit Control 4.3.1.3. Avalon® Streaming RX Interface 4.3.1.4. Avalon® Streaming TX Interface 4.3.1.5. Tag Allocation
4.3.1.2. Credit Control x
4.3.1.2.1. Credit Interface - Data and Header 4.3.1.2.2. Credit Initialization 4.3.1.2.3. Credit Update/Release 4.3.1.2.4. RX Flow Control Interface 4.3.1.2.5. TX Flow Control Interface
4.3.1.4. Avalon® Streaming TX Interface x
4.3.1.4.1. Avalon® Streaming TX Interface pX_tx_st_ready_o Behavior
4.3.1.5. Tag Allocation x
4.3.1.5.1. Completion Buffer Size
4.3.3. Interrupt Interface x
4.3.3.1. Legacy Interrupts 4.3.3.2. MSI 4.3.3.3. MSI-X
4.3.3.3. MSI-X x
4.3.3.3.1. Implementing MSI-X Interrupts
4.3.8. Power Management Interface x
4.3.8.1. D3Hot Entry 4.3.8.2. D3Hot Exit 4.3.8.3. D3Cold Entry 4.3.8.4. D3Cold Exit
4.3.8.2. D3Hot Exit x
4.3.8.2.1. D3Hot Exit Initiated by Host 4.3.8.2.2. D3Hot Exit Initiated by EP
4.4. PIPE Direct Mode x
4.4.1. Data Signals 4.4.2. Command and Status Signals 4.4.3. Message Bus Signals 4.4.4. Deskew Signals 4.4.5. PIPE Direct Reset Sequence 4.4.6. PIPE Direct Speed Change 4.4.7. PIPE Lane Reset Staggering 4.4.8. Unused Lanes in PIPE Direct Mode
4.4.1. Data Signals x
4.4.1.1. Transmit Signals 4.4.1.2. Receive Signals
4.4.4. Deskew Signals x
4.4.4.1. MAC to PHY (M2P) Signals 4.4.4.2. PHY to MAC (P2M) Signals
5. Parameters x
5.1. Top-Level Settings 5.2. Core Parameters
5.2. Core Parameters x
5.2.1. Avalon Parameters 5.2.2. Base Address Registers 5.2.3. PCI Express and PCI Capabilities Parameters
5.2.3. PCI Express and PCI Capabilities Parameters x
5.2.3.1. Device Capabilities 5.2.3.2. VirtIO Parameters 5.2.3.3. Link Capabilities 5.2.3.4. Legacy Interrupt Pin Register 5.2.3.5. MSI Capabilities 5.2.3.6. MSI-X Capabilities 5.2.3.7. Slot Capabilities 5.2.3.8. Latency Tolerance Reporting (LTR) 5.2.3.9. Process Address Space ID (PASID) 5.2.3.10. Device Serial Number Capability 5.2.3.11. Page Request Service (PRS) 5.2.3.12. Access Control Service (ACS) 5.2.3.13. Power Management 5.2.3.14. Vendor Specific Extended Capability (VSEC) Registers 5.2.3.15. TLP Processing Hints (TPH) 5.2.3.16. Address Translation Services (ATS) Capabilities 5.2.3.17. Precision Time Management (PTM)
6. Troubleshooting/Debugging x
6.1. Hardware Debug 6.2. Operating System Tools and Utilities 6.3. Signal Tap Logic Analyzer 6.4. Using the Hard IP Reconfiguration Interface for Debugging 6.5. Other Interfaces That Can Be Used for Debug Activities 6.6. Debug Toolkit
6.1. Hardware Debug x
6.1.1. Debugging Link Training Issues 6.1.2. Debugging Device Enumeration Issues 6.1.3. Debugging Data Transfer and Performance Issues
6.1.3. Debugging Data Transfer and Performance Issues x
6.1.3.1. Advanced Error Reporting (AER)
6.2. Operating System Tools and Utilities x
6.2.1. Using lspci Utility to Read Negotiated Link Speed
6.4. Using the Hard IP Reconfiguration Interface for Debugging x
6.4.1. Using the Hard IP Reconfiguration Interface to Enable and Read ECRC and LCRC Error Counts
6.6. Debug Toolkit x
6.6.1. Overview 6.6.2. Enabling the R-Tile Debug Toolkit 6.6.3. Launching the R-tile Debug Toolkit 6.6.4. Using the R-Tile Debug Toolkit
6.6.4. Using the R-Tile Debug Toolkit x
6.6.4.1. R-Tile Information 6.6.4.2. Event Counters 6.6.4.3. Configuration Space
C. Implementation of Address Translation Services (ATS) in Endpoint Mode x
C.1. Sending Translated/Untranslated Requests C.2. Sending a Page Request Message from the Endpoint (EP) to the Root Complex (RC) C.3. Invalidating Requests/Completions
D. Packets Forwarded to the User Application in TLP Bypass Mode x
D.1. EP TLP Bypass Mode (Upstream) D.2. RC TLP Bypass Mode (Downstream)
1. About the R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express
2. IP Architecture and Functional Description
3. Advanced Features
4. Interfaces
5. Parameters
6. Troubleshooting/Debugging
7. R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express* User Guide Archives
8. Document Revision History for the R-Tile Avalon® Streaming Intel FPGA IP for PCI Express User Guide
A. Configuration Space Registers
B. Root Port Enumeration
C. Implementation of Address Translation Services (ATS) in Endpoint Mode
D. Packets Forwarded to the User Application in TLP Bypass Mode

2.3.3.2. Data Link Layer Overview

The Data Link Layer (DLL) is located between the Transaction Layer and the Physical Layer. It maintains packet integrity and communicates (by DLL packet transmission) at the PCI Express link level.

The DLL implements the following functions:

  • Link management through the reception and transmission of DLL Packets (DLLP), which are used for the following functions:
    • Power management of DLLP reception and transmission
    • To transmit and receive ACK/NAK packets
    • Data integrity through the generation and checking of CRCs for TLPs and DLLPs
    • TLP retransmission in case of NAK DLLP reception or replay timeout, using the retry (replay) buffer
    • Management of the retry buffer
    • Link retraining requests in case of error through the Link Training and Status State Machine (LTSSM) of the Physical Layer
Figure 10. Data Link Layer

The DLL has the following sub-blocks:

  • Data Link Control and Management State Machine—This state machine connects to both the Physical Layer’s LTSSM state machine and the Transaction Layer. It initializes the link and flow control credits and reports status to the Transaction Layer.
  • Power Management—This function handles the handshake to enter low power mode. Such a transition is based on register values in the Configuration Space and received Power Management (PM) DLLPs. For more details on the power states supported by the R-Tile Avalon® -ST IP for PCIe, refer to section Power Management Interface.
  • Data Link Layer Packet Generator and Checker—This block is associated with the DLLP’s 16-bit CRC and maintains the integrity of transmitted packets.
  • Transaction Layer Packet Generator—This block generates transmit packets, including a sequence number and a 32-bit Link CRC (LCRC). The packets are also sent to the retry buffer for internal storage. In retry mode, the TLP generator receives the packets from the retry buffer and generates the CRC for the transmit packet.
  • Retry Buffer—The retry buffer stores TLPs and retransmits all unacknowledged packets in the case of NAK DLLP reception. In case of ACK DLLP reception, the retry buffer discards all acknowledged packets.
  • ACK/NAK Packets—The ACK/NAK block handles ACK/NAK DLLPs and generates the sequence number of transmitted packets.
  • Transaction Layer Packet Checker—This block checks the integrity of the received TLP and generates a request for transmission of an ACK/NAK DLLP.
  • TX Arbitration—This block arbitrates transactions, prioritizing in the following order:
    • Initialize FC Data Link Layer packet
    • ACK/NAK DLLP (high priority)
    • Update FC DLLP (high priority)
    • PM DLLP
    • Retry buffer TLP
    • TLP
    • Update FC DLLP (low priority)
    • ACK/NAK FC DLLP (low priority)
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