Stratix V Avalon-MM Interface for PCIe Solutions: User Guide

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ID 683411
Date 5/21/2017
Public
Document Table of Contents
Document Table of Contents x
1. Datasheet 2. Getting Started with the Avalon-MM Design Example 3. Parameter Settings 4. 64- or 128-Bit Avalon-MM Interface to the Endpoint Application Layer 5. Registers 6. Interrupts for Endpoints 7. Error Handling A. PCI Express Protocol Stack 8. Transceiver PHY IP Reconfiguration 9. Throughput Optimization 10. Design Implementation 11. Additional Features 12. Debugging B. Frequently Asked Questions for PCI Express C. Lane Initialization and Reversal D. Document Revision History
1. Datasheet x
1.1. Stratix V Avalon-MM Interface for PCIe Datasheet 1.2. Features 1.3. Release Information 1.4. Device Family Support 1.5. Configurations 1.6. Design Examples 1.7. IP Core Verification 1.8. Resource Utilization 1.9. Recommended Speed Grades 1.10. Creating a Design for PCI Express
1.7. IP Core Verification x
1.7.1. Compatibility Testing Environment
2. Getting Started with the Avalon-MM Design Example x
2.1. Running Qsys 2.2. Generating the Example Design 2.3. Understanding Simulation Log File Generation 2.4. Running a Gate-Level Simulation 2.5. Simulating the Single DWord Design 2.6. Generating Synthesis Files 2.7. Creating a Quartus® Prime Project 2.8. Compiling the Design 2.9. Programming a Device 2.10. Understanding Channel Placement Guidelines
3. Parameter Settings x
3.1. System Settings 3.2. Base Address Register (BAR) Settings 3.3. Device Identification Registers 3.4. PCI Express and PCI Capabilities Parameters 3.5. Avalon Memory‑Mapped System Settings
3.4. PCI Express and PCI Capabilities Parameters x
3.4.1. Device Capabilities 3.4.2. Error Reporting 3.4.3. Link Capabilities 3.4.4. MSI and MSI-X Capabilities 3.4.5. Power Management
4. 64- or 128-Bit Avalon-MM Interface to the Endpoint Application Layer x
4.1. 32-Bit Non-Bursting Avalon-MM Control Register Access (CRA) Slave Signals 4.2. Bursting and Non-Bursting Avalon® -MM Module Signals 4.3. 64- or 128-Bit Bursting TX Avalon-MM Slave Signals 4.4. Clock Signals 4.5. Reset 4.6. Interrupts for Endpoints when Multiple MSI/MSI-X Support Is Enabled 4.7. Hard IP Status Signals 4.8. Physical Layer Interface Signals
4.7. Hard IP Status Signals x
4.7.1. Hard IP Reconfiguration Interface
4.8. Physical Layer Interface Signals x
4.8.1. Hard IP Status Extension 4.8.2. Serial Data Signals 4.8.3. PIPE Interface Signals 4.8.4. Test Signals
4.8.2. Serial Data Signals x
4.8.2.1. Physical Layout of Hard IP in Stratix V GX/GT/GS Devices 4.8.2.2. Channel Placement in Arria V GZ and Stratix V GX/GT/GS Devices
5. Registers x
5.1. Correspondence between Configuration Space Registers and the PCIe Specification 5.2. Type 0 Configuration Space Registers 5.3. Type 1 Configuration Space Registers 5.4. PCI Express Capability Structures 5.5. Intel-Defined VSEC Registers 5.6. CvP Registers 5.7. 64- or 128-Bit Avalon-MM Bridge Register Descriptions 5.8. Programming Model for Avalon-MM Root Port 5.9. Uncorrectable Internal Error Mask Register 5.10. Uncorrectable Internal Error Status Register 5.11. Correctable Internal Error Mask Register 5.12. Correctable Internal Error Status Register
5.7. 64- or 128-Bit Avalon-MM Bridge Register Descriptions x
5.7.1. Avalon-MM to PCI Express Interrupt Registers
5.7.1. Avalon-MM to PCI Express Interrupt Registers x
5.7.1.1. Avalon-MM to PCI Express Interrupt Status Registers 5.7.1.2. Avalon-MM to PCI Express Interrupt Enable Registers 5.7.1.3. PCI Express Mailbox Registers 5.7.1.4. Avalon-MM-to-PCI Express Address Translation Table 5.7.1.5. PCI Express to Avalon-MM Interrupt Status and Enable Registers for Endpoints 5.7.1.6. Avalon-MM Mailbox Registers 5.7.1.7. Control Register Access (CRA) Avalon-MM Slave Port
5.8. Programming Model for Avalon-MM Root Port x
5.8.1. Sending a Write TLP 5.8.2. Sending a Read TLP or Receiving a Non-Posted Completion TLP 5.8.3. Examples of Reading and Writing BAR0 Using the CRA Interface 5.8.4. PCI Express to Avalon-MM Interrupt Status and Enable Registers for Root Ports 5.8.5. Root Port TLP Data Registers
6. Interrupts for Endpoints x
6.1. Enabling MSI or Legacy Interrupts 6.2. Generation of Avalon-MM Interrupts 6.3. Interrupts for Endpoints Using the Avalon-MM Interface with Multiple MSI/MSI-X Support
7. Error Handling x
7.1. Physical Layer Errors 7.2. Data Link Layer Errors 7.3. Transaction Layer Errors 7.4. Error Reporting and Data Poisoning 7.5. Uncorrectable and Correctable Error Status Bits
A. PCI Express Protocol Stack x
A.1. Top-Level Interfaces A.2. Data Link Layer A.3. Physical Layer A.4. 32-Bit PCI Express Avalon-MM Bridge A.5. Completer Only Single Dword Endpoint
A.1. Top-Level Interfaces x
A.1.1. Avalon-MM Interface A.1.2. Clocks and Reset A.1.3. Transceiver Reconfiguration A.1.4. Interrupts A.1.5. PIPE
A.4. 32-Bit PCI Express Avalon-MM Bridge x
A.4.1. Avalon‑MM Bridge TLPs A.4.2. Avalon-MM-to-PCI Express Write Requests A.4.3. Avalon-MM-to-PCI Express Upstream Read Requests A.4.4. PCI Express-to-Avalon-MM Read Completions A.4.5. PCI Express-to-Avalon-MM Downstream Write Requests A.4.6. PCI Express-to-Avalon-MM Downstream Read Requests A.4.7. Avalon-MM-to-PCI Express Read Completions A.4.8. PCI Express-to-Avalon-MM Address Translation for 32-Bit Bridge A.4.9. Minimizing BAR Sizes and the PCIe Address Space A.4.10. Avalon® -MM-to-PCI Express Address Translation Algorithm for 32-Bit Addressing
A.5. Completer Only Single Dword Endpoint x
A.5.1. RX Block A.5.2. Avalon-MM RX Master Block A.5.3. TX Block A.5.4. Interrupt Handler Block
8. Transceiver PHY IP Reconfiguration x
8.1. Connecting the Transceiver Reconfiguration Controller IP Core 8.2. Transceiver Reconfiguration Controller Connectivity for Designs Using CvP
9. Throughput Optimization x
9.1. Throughput of Posted Writes 9.2. Throughput of Non-Posted Reads
10. Design Implementation x
10.1. Making Analog QSF Assignments Using the Assignment Editor 10.2. Making Pin Assignments to Assign I/O Standard to Serial Data Pins 10.3. Recommended Reset Sequence to Avoid Link Training Issues 10.4. SDC Timing Constraints
11. Additional Features x
11.1. Configuration over Protocol (CvP) 11.2. Autonomous Mode 11.3. ECRC
11.2. Autonomous Mode x
11.2.1. Enabling Autonomous Mode 11.2.2. Enabling CvP Initialization
11.3. ECRC x
11.3.1. ECRC on the RX Path 11.3.2. ECRC on the TX Path
12. Debugging x
12.1. Hardware Bring-Up Issues 12.2. Link Training 12.3. Use Third-Party PCIe Analyzer 12.4. BIOS Enumeration Issues
12.2. Link Training x
12.2.1. Debugging Link that Fails To Reach L0
D. Document Revision History x
D.1. Cyclone® V Avalon® Memory Mapped (Avalon-MM) Interface for PCIe* Solutions User Guide Revision History
1. Datasheet
2. Getting Started with the Avalon-MM Design Example
3. Parameter Settings
4. 64- or 128-Bit Avalon-MM Interface to the Endpoint Application Layer
5. Registers
6. Interrupts for Endpoints
7. Error Handling
A. PCI Express Protocol Stack
8. Transceiver PHY IP Reconfiguration
9. Throughput Optimization
10. Design Implementation
11. Additional Features
12. Debugging
B. Frequently Asked Questions for PCI Express
C. Lane Initialization and Reversal
D. Document Revision History

A.3. Physical Layer

The Physical Layer is the lowest level of the PCI Express protocol stack. It is the layer closest to the serial link. It encodes and transmits packets across a link and accepts and decodes received packets. The Physical Layer connects to the link through a high‑speed SERDES interface running at 2.5 Gbps for Gen1 implementations, at 2.5 or 5.0 Gbps for Gen2 implementations, and at 2.5, 5.0 or 8.0 Gbps for Gen3 implementations.

The Physical Layer is responsible for the following actions:

  • Training the link
  • Scrambling/descrambling and 8B/10B encoding/decoding for 2.5 Gbps (Gen1), 5.0 Gbps (Gen2), or 128b/130b encoding/decoding of 8.0 Gbps (Gen3) per lane
  • Serializing and deserializing data
  • Equalization (Gen3)
  • Operating the PIPE 3.0 Interface
  • Implementing auto speed negotiation (Gen2 and Gen3)
  • Transmitting and decoding the training sequence
  • Providing hardware autonomous speed control
  • Implementing auto lane reversal

The Physical Layer is subdivided by the PIPE Interface Specification into two layers (bracketed horizontally in above figure):

  • PHYMAC—The MAC layer includes the LTSSM and the scrambling/descrambling. byte reordering, and multilane deskew functions.
  • PHY Layer—The PHY layer includes the 8B/10B encode and decode functions for Gen1 and Gen2. It includes 128b/130b encode and decode functions for Gen3. The PHY also includes elastic buffering and serialization/deserialization functions.
The Physical Layer integrates both digital and analog elements. Intel designed the PIPE interface to separate the PHYMAC from the PHY. The Intel Hard IP for PCI Express complies with the PIPE interface specification.
Note: The internal PIPE interface is visible for simulation. It is not available for debugging in hardware using a logic analyzer such as Signal Tap. If you try to connect Signal Tap to this interface the design fails compilation.
Figure 31. Physical Layer Architecture

The PHYMAC block comprises four main sub-blocks:

  • MAC Lane—Both the RX and the TX path use this block.
    • On the RX side, the block decodes the Physical Layer packet and reports to the LTSSM the type and number of TS1/TS2 ordered sets received.
    • On the TX side, the block multiplexes data from the DLL and the Ordered Set and SKP sub-block (LTSTX). It also adds lane specific information, including the lane number and the force PAD value when the LTSSM disables the lane during initialization.
  • LTSSM—This block implements the LTSSM and logic that tracks TX and RX training sequences on each lane.
  • For transmission, it interacts with each MAC lane sub-block and with the LTSTX sub-block by asserting both global and per-lane control bits to generate specific Physical Layer packets.
    • On the receive path, it receives the Physical Layer packets reported by each MAC lane sub-block. It also enables the multilane deskew block. This block reports the Physical Layer status to higher layers.
    • LTSTX (Ordered Set and SKP Generation)—This sub-block generates the Physical Layer packet. It receives control signals from the LTSSM block and generates Physical Layer packet for each lane. It generates the same Physical Layer Packet for all lanes and PAD symbols for the link or lane number in the corresponding TS1/TS2 fields. The block also handles the receiver detection operation to the PCS sub-layer by asserting predefined PIPE signals and waiting for the result. It also generates a SKP Ordered Set at every predefined timeslot and interacts with the TX alignment block to prevent the insertion of a SKP Ordered Set in the middle of packet.
    • Deskew—This sub-block performs the multilane deskew function and the RX alignment between the initialized lanes and the datapath. The multilane deskew implements an eight-word FIFO buffer for each lane to store symbols. Each symbol includes eight data bits, one disparity bit, and one control bit. The FIFO discards the FTS, COM, and SKP symbols and replaces PAD and IDL with D0.0 data. When all eight FIFOs contain data, a read can occur. When the multilane lane deskew block is first enabled, each FIFO begins writing after the first COM is detected. If all lanes have not detected a COM symbol after seven clock cycles, they are reset and the resynchronization process restarts, or else the RX alignment function recreates a 64-bit data word which is sent to the DLL.
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