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

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ID 683501
Date 10/06/2021
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Document Table of Contents
Document Table of Contents x
1. Introduction 2. IP Architecture and Functional Description 3. Parameters 4. Interfaces 5. Advanced Features 6. R-tile Avalon® Streaming Intel® FPGA IP for PCI Express* User Guide Archives 7. 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. Introduction 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
2. IP Architecture and Functional Description x
2.1. Overview 2.2. PCIe Hard IP Mode 2.3. PIPE Direct Mode
2.2. PCIe Hard IP Mode x
2.2.1. Clocking 2.2.2. Reset 2.2.3. PCI Express Protocol Stack
2.2.3. PCI Express Protocol Stack x
2.2.3.1. PMA/PCS 2.2.3.2. Data Link Layer Overview 2.2.3.3. Transaction Layer Overview
2.3. PIPE Direct Mode x
2.3.1. Clocking 2.3.2. Reset 2.3.3. PIPE Layer
3. Parameters x
3.1. Top-Level Settings 3.2. Core Parameters
4. Interfaces x
4.1. Overview 4.2. Clocks and Resets 4.3. Serial Data Interface 4.4. PCI Express Mode 4.5. PIPE Direct Mode
4.2. Clocks and Resets x
4.2.1. Clocks 4.2.2. Resets
4.4. PCI Express Mode x
4.4.1. Avalon® Streaming Interface 4.4.2. Precision Time Measurement (PTM) Interface 4.4.3. Interrupt Interface 4.4.4. Hard IP Reconfiguration Interface 4.4.5. Error Interface 4.4.6. Completion Timeout Interface 4.4.7. Configuration Intercept Interface 4.4.8. Power Management Interface 4.4.9. Hard IP Status Interface 4.4.10. Page Request Services (PRS) Interface 4.4.11. Function-Level Reset (FLR) Interface 4.4.12. SR-IOV VF Error Flag Interface 4.4.13. General Purpose VSEC Interface
4.4.1. Avalon® Streaming Interface x
4.4.1.1. TLP Header and Data Alignment for the Avalon® streaming RX and TX Interfaces 4.4.1.2. Credit Control 4.4.1.3. Avalon® Streaming RX Interface 4.4.1.4. Avalon® Streaming TX Interface 4.4.1.5. Tag Allocation
4.4.1.2. Credit Control x
4.4.1.2.1. Credit Interface - Data and Header 4.4.1.2.2. Credit Initialization 4.4.1.2.3. Credit Update/Release 4.4.1.2.4. RX Flow Control Interface 4.4.1.2.5. TX Flow Control Interface
4.4.1.2.4. RX Flow Control Interface x
4.4.1.2.4.1. Completion Buffer Size
4.4.1.4. Avalon® Streaming TX Interface x
4.4.1.4.1. Avalon® Streaming TX Interface tx_st_ready_o Behavior
4.4.3. Interrupt Interface x
4.4.3.1. Legacy Interrupts 4.4.3.2. MSI 4.4.3.3. MSI-X
4.4.3.3. MSI-X x
4.4.3.3.1. Implementing MSI-X Interrupts
4.4.8. Power Management Interface x
4.4.8.1. Endpoint D3Hot Entry 4.4.8.2. Endpoint D3Hot Exit
4.5. PIPE Direct Mode x
4.5.1. Data Signals 4.5.2. Message Channel 4.5.3. Deskew Channel 4.5.4. PIPE Direct Reset Sequence 4.5.5. PIPE Direct Speed Change 4.5.6. PIPE Lane Reset Staggering 4.5.7. Unused Lanes in PIPE Direct Mode 4.5.8. PIPE Direct Mode TX/RX Datapaths
4.5.1. Data Signals x
4.5.1.1. Transmit Signals 4.5.1.2. Receive Signals
5. Advanced Features x
5.1. PCIe Port Bifurcation and PHY Channel Mapping 5.2. Virtualization Support 5.3. TLP Bypass Mode
5.2. Virtualization Support x
5.2.1. SR-IOV Support 5.2.2. VirtIO Support
5.2.1. SR-IOV Support x
5.2.1.1. SR-IOV Supported Features List 5.2.1.2. Implementation 5.2.1.3. VF to PF Mapping 5.2.1.4. Function Level Reset (FLR)
5.2.1.2. Implementation x
5.2.1.2.1. VF Error Flag Interface (for x16/x8 Cores Only)
5.2.2. VirtIO Support x
5.2.2.1. VirtIO Supported Features List 5.2.2.2. Overview 5.2.2.3. Parameters 5.2.2.4. VirtIO PCI Configuration Access Interface 5.2.2.5. Registers
5.2.2.5. Registers x
5.2.2.5.1. VirtIO Common Configuration Capability Register (Address: 0x012) 5.2.2.5.2. VirtIO Common Configuration BAR Indicator Register (Address: 0x013) 5.2.2.5.3. VirtIO Common Configuration BAR Offset Register (Address: 0x014) 5.2.2.5.4. VirtIO Common Configuration Structure Length Register (Address 0x015) 5.2.2.5.5. VirtIO Notifications Capability Register (Address: 0x016) 5.2.2.5.6. VirtIO Notifications BAR Indicator Register (Address: 0x017) 5.2.2.5.7. VirtIO Notifications BAR Offset Register (Address: 0x018) 5.2.2.5.8. VirtIO Notifications Structure Length Register (Address: 0x019) 5.2.2.5.9. VirtIO Notifications Notify Off Multiplier Register (Address: 0x01A) 5.2.2.5.10. VirtIO ISR Status Capability Register (Address: 0x02F) 5.2.2.5.11. VirtIO ISR Status BAR Indicator Register (Address: 0x030) 5.2.2.5.12. VirtIO ISR Status BAR Offset Register (Address: 0x031) 5.2.2.5.13. VirtIO ISR Status Structure Length Register (Address: 0x032) 5.2.2.5.14. VirtIO Device Specific Capability Register (Address: 0x033) 5.2.2.5.15. VirtIO Device Specific BAR Indicator Register (Address: 0x034) 5.2.2.5.16. VirtIO Device Specific BAR Offset Register (Address 0x035) 5.2.2.5.17. VirtIO Device Specific Structure Length Register (Address: 0x036) 5.2.2.5.18. VirtIO PCI Configuration Access Capability Register (Address: 0x037) 5.2.2.5.19. VirtIO PCI Configuration Access BAR Indicator Register (Address: 0x038) 5.2.2.5.20. VirtIO PCI Configuration Access BAR Offset Register (Address: 0x039) 5.2.2.5.21. VirtIO PCI Configuration Access Structure Length Register (Address: 0x03A) 5.2.2.5.22. VirtIO PCI Configuration Access Data Register (Address: 0x03B)
5.3. TLP Bypass Mode x
5.3.1. Overview 5.3.2. Register Settings for the TLP Bypass Mode 5.3.3. User Avalon Memory-mapped Interface 5.3.4. Avalon® Streaming Interface
5.3.2. Register Settings for the TLP Bypass Mode x
5.3.2.1. TLPBYPASS_ERR_EN (Address 0x1314) 5.3.2.2. TLPBYPASS_ERR_STATUS (Address 0x1310)
5.3.4. Avalon® Streaming Interface x
5.3.4.1. Configuration TLP 5.3.4.2. Transmit Interface 5.3.4.3. Receive Interface 5.3.4.4. Malformed TLP 5.3.4.5. ECRC
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. Introduction
2. IP Architecture and Functional Description
3. Parameters
4. Interfaces
5. Advanced Features
6. R-tile Avalon® Streaming Intel® FPGA IP for PCI Express* User Guide Archives
7. 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

4.4.3.3. MSI-X

The R-tile IP for PCIe provides a Configuration Intercept Interface. User soft logic can monitor this interface to get MSI-X Enable and MSI-X function mask related information. User application logic needs to implement the MSI-X tables for all PFs and VFs at the memory space pointed to by the BARs as a part of your Application Layer.

For more details on the MSI-X related information that you can obtain from the Configuration Intercept Interface, refer to the MSI-X Registers section in the Registers chapter.

MSI-X is an optional feature that allows the user application to support large amount of vectors with independent message data and address for each vector.

When MSI-X is supported, you need to specify the size and the location (BARs and offsets) of the MSI-X table and PBA. MSI-X can support up to 2048 vectors per function versus 32 vectors per function for MSI.

A function is allowed to send MSI-X messages when MSI-X is enabled and the function is not masked. The application uses the Configuration Intercept Interface to access this information.

When the application needs to generate an MSI-X, it will use the contents of the MSI-X Table (Address and Data) and generate a Memory Write through the Avalon® -ST interface.

You can enable MSI-X interrupts by turning on the Enable MSI-X option in the MSI-X tab under the PCI Express/PCI Capabilities tab in the parameter editor. If you turn on the Enable MSI-X option, you should implement the MSI-X table structures at the memory space pointed to by the BARs as a part of your Application Layer.

The MSI-X Capability Structure contains information about the MSI-X Table and PBA Structure. For example, it contains pointers to the bases of the MSI-X Table and PBA Structure, expressed as offsets from the addresses in the function's BARs. The Message Control register within the MSI-X Capability Structure also contains the MSI-X Enable bit, the Function Mask bit, and the size of the MSI-X Table.

MSI-X interrupts are standard Memory Writes, therefore Memory Write ordering rules apply.

Example:

Table 27.  MSI-X Configuration
MSI-X Vector MSI-X Upper Address MSI-X Lower Address MSI-X Data
0 0x00000001 0xAAAA0000 0x00000001
1 0x00000001 0xBBBB0000 0x00000002
2 0x00000001 0xCCCC0000 0x00000003
Table 28.  PBA Table
PBA Table PBA Entries
Offset 0 0x0

If the application needs to generate an MSI-X interrupt (vector 1), it will read the MSI-X Table information, generate a MWR TLP through the Avalon® -ST interface and assert the corresponding PBA bits (bit[1]) in a similar fashion as for MSI generation.

The generated TLP will be sent to address 0x00000001_BBBB0000 and the data will be 0x00000002. When the MSI-X has been sent, the application can clear the associated PBA bits.

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