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

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ID 683093
Date 5/03/2019
Public
Document Table of Contents
Document Table of Contents x
1. Datasheet 2. Getting Started with the Stratix V Hard IP for PCI Express 3. Getting Started with the Configuration Space Bypass Mode Qsys Example Design 4. Parameter Settings 5. Interfaces and Signal Descriptions 6. Registers 7. Interrupts 8. Error Handling 9. PCI Express Protocol Stack 10. Transaction Layer Protocol (TLP) Details 11. Throughput Optimization 12. Design Implementation 13. Additional Features 14. Hard IP Reconfiguration 15. Transceiver PHY IP Reconfiguration 16. Testbench and Design Example 17. Debugging A. Frequently Asked Questions for PCI Express B. Lane Initialization and Reversal C. Document Revision History
1. Datasheet x
1.1. Stratix V Avalon-ST Interface for PCIe Datasheet 1.2. Release Information 1.3. Device Family Support 1.4. Configurations 1.5. Avalon-ST Example Designs 1.6. Debug Features 1.7. IP Core Verification 1.8. Resource Utilization 1.9. Recommended Speed Grades 1.10. Creating a Design for PCI Express
1.1. Stratix V Avalon-ST Interface for PCIe Datasheet x
1.1.1. Features
1.7. IP Core Verification x
1.7.1. Compatibility Testing Environment
2. Getting Started with the Stratix V Hard IP for PCI Express x
2.1. Qsys Design Flow
2.1. Qsys Design Flow x
2.1.1. Generating the Testbench 2.1.2. Simulating the Example Design 2.1.3. Generating Synthesis Files 2.1.4. Understanding the Files Generated 2.1.5. Understanding Simulation Log File Generation 2.1.6. Understanding Physical Placement of the PCIe IP Core 2.1.7. Compiling the Design in the Qsys Design Flow 2.1.8. Modifying the Example Design 2.1.9. Using the IP Catalog To Generate Your Stratix V Hard IP for PCI Express as a Separate Component
3. Getting Started with the Configuration Space Bypass Mode Qsys Example Design x
3.1. Copying the Configuration Space Bypass Mode Example Design 3.2. Generating the Qsys System 3.3. Simulating the Example Design
3.2. Generating the Qsys System x
3.2.1. Generating Synthesis Files 3.2.2. Understanding the Generated Files 3.2.3. Understanding Simulation Log File Generation
3.3. Simulating the Example Design x
3.3.1. Timing for Configuration Read to Function 0 for the 256-Bit Avalon-ST Interface 3.3.2. Timing for Configuration Write to Function 0 for the 256-Bit Avalon-ST Interface 3.3.3. Timing for Memory Write and Read of Function 1 256-Bit Avalon-ST Interface 3.3.4. Partial Transcript for Configuration Space Bypass Simulation
4. Parameter Settings x
4.1. System Settings 4.2. Base Address Register (BAR) and Expansion ROM Settings 4.3. Base and Limit Registers for Root Ports 4.4. Device Identification Registers 4.5. PCI Express and PCI Capabilities Parameters 4.6. Vendor Specific Extended Capability (VSEC) 4.7. PHY Characteristics
4.5. PCI Express and PCI Capabilities Parameters x
4.5.1. PCI Express and PCI Capabilities 4.5.2. Error Reporting 4.5.3. Link Capabilities 4.5.4. MSI and MSI-X Capabilities 4.5.5. Slot Capabilities 4.5.6. Power Management
5. Interfaces and Signal Descriptions x
5.1. Clock Signals 5.2. Reset, Status, and Link Training Signals 5.3. ECRC Forwarding 5.4. Error Signals 5.5. Interrupts for Endpoints 5.6. Interrupts for Root Ports 5.7. Completion Side Band Signals 5.8. Configuration Space Bypass Mode Interface Signals 5.9. Parity Signals 5.10. LMI Signals 5.11. Transaction Layer Configuration Space Signals 5.12. Hard IP Reconfiguration Interface 5.13. Power Management Signals 5.14. Physical Layer Interface Signals
5.11. Transaction Layer Configuration Space Signals x
5.11.1. Configuration Space Register Access Timing 5.11.2. Configuration Space Register Access
5.14. Physical Layer Interface Signals x
5.14.1. Transceiver Reconfiguration 5.14.2. Serial Data Signals 5.14.3. PIPE Interface Signals 5.14.4. Test Signals
5.14.2. Serial Data Signals x
5.14.2.1. Physical Layout of Hard IP in Stratix V GX/GT/GS Devices 5.14.2.2. Channel Placement in Arria V GZ and Stratix V GX/GT/GS Devices
6. Registers x
6.1. Correspondence between Configuration Space Registers and the PCIe Specification 6.2. Type 0 Configuration Space Registers 6.3. Type 1 Configuration Space Registers 6.4. PCI Express Capability Structures 6.5. Intel-Defined VSEC Registers 6.6. CvP Registers 6.7. Uncorrectable Internal Error Mask Register 6.8. Uncorrectable Internal Error Status Register 6.9. Correctable Internal Error Mask Register 6.10. Correctable Internal Error Status Register
7. Interrupts x
7.1. Interrupts for Endpoints 7.2. Interrupts for Root Ports
7.1. Interrupts for Endpoints x
7.1.1. MSI and Legacy Interrupts 7.1.2. MSI-X 7.1.3. Implementing MSI-X Interrupts 7.1.4. Legacy Interrupts
8. Error Handling x
8.1. Physical Layer Errors 8.2. Data Link Layer Errors 8.3. Transaction Layer Errors 8.4. Error Reporting and Data Poisoning 8.5. Uncorrectable and Correctable Error Status Bits
9. PCI Express Protocol Stack x
9.1. Top-Level Interfaces 9.2. Transaction Layer 9.3. Data Link Layer 9.4. Physical Layer
9.1. Top-Level Interfaces x
9.1.1. Avalon-ST Interface 9.1.2. Clocks and Reset 9.1.3. Local Management Interface (LMI Interface) 9.1.4. Hard IP Reconfiguration 9.1.5. Transceiver Reconfiguration 9.1.6. Interrupts 9.1.7. PIPE
9.2. Transaction Layer x
9.2.1. Configuration Space 9.2.2. Configuration Space Bypass Mode
10. Transaction Layer Protocol (TLP) Details x
10.1. Supported Message Types 10.2. Transaction Layer Routing Rules 10.3. Receive Buffer Reordering
10.1. Supported Message Types x
10.1.1. INTX Messages 10.1.2. Power Management Messages 10.1.3. Error Signaling Messages 10.1.4. Locked Transaction Message 10.1.5. Slot Power Limit Message 10.1.6. Vendor-Defined Messages 10.1.7. Hot Plug Messages
10.3. Receive Buffer Reordering x
10.3.1. Using Relaxed Ordering
11. Throughput Optimization x
11.1. Throughput of Posted Writes 11.2. Throughput of Non-Posted Reads
12. Design Implementation x
12.1. Making Analog QSF Assignments Using the Assignment Editor 12.2. Making Pin Assignments to Assign I/O Standard to Serial Data Pins 12.3. Recommended Reset Sequence to Avoid Link Training Issues 12.4. SDC Timing Constraints
13. Additional Features x
13.1. Configuration over Protocol (CvP) 13.2. Autonomous Mode 13.3. ECRC
13.2. Autonomous Mode x
13.2.1. Enabling Autonomous Mode 13.2.2. Enabling CvP Initialization
13.3. ECRC x
13.3.1. ECRC on the RX Path 13.3.2. ECRC on the TX Path
15. Transceiver PHY IP Reconfiguration x
15.1. Connecting the Transceiver Reconfiguration Controller IP Core 15.2. Transceiver Reconfiguration Controller Connectivity for Designs Using CvP
16. Testbench and Design Example x
16.1. Endpoint Testbench 16.2. Root Port Testbench 16.3. Test Driver Module 16.4. Root Port Design Example 16.5. Root Port BFM Overview 16.6. BFM Procedures and Functions 16.7. Setting Up Simulation
16.1. Endpoint Testbench x
16.1.1. Endpoint Testbench for SR-IOV
16.5. Root Port BFM Overview x
16.5.1. BFM Memory Map 16.5.2. Configuration Space Bus and Device Numbering 16.5.3. Configuration of Root Port and Endpoint 16.5.4. Issuing Read and Write Transactions to the Application Layer
16.6. BFM Procedures and Functions x
16.6.1. ebfm_barwr Procedure 16.6.2. ebfm_barwr_imm Procedure 16.6.3. ebfm_barrd_wait Procedure 16.6.4. ebfm_barrd_nowt Procedure 16.6.5. ebfm_cfgwr_imm_wait Procedure 16.6.6. ebfm_cfgwr_imm_nowt Procedure 16.6.7. ebfm_cfgrd_wait Procedure 16.6.8. ebfm_cfgrd_nowt Procedure 16.6.9. BFM Configuration Procedures 16.6.10. BFM Shared Memory Access Procedures 16.6.11. BFM Log and Message Procedures 16.6.12. Verilog HDL Formatting Functions
16.6.9. BFM Configuration Procedures x
16.6.9.1. ebfm_cfg_rp_ep Procedure 16.6.9.2. ebfm_cfg_decode_bar Procedure
16.6.10. BFM Shared Memory Access Procedures x
16.6.10.1. Shared Memory Constants 16.6.10.2. shmem_write Task 16.6.10.3. shmem_read Function 16.6.10.4. shmem_display Verilog HDL Function 16.6.10.5. shmem_fill Procedure 16.6.10.6. shmem_chk_ok Function
16.6.11. BFM Log and Message Procedures x
16.6.11.1. ebfm_display Verilog HDL Function 16.6.11.2. ebfm_log_stop_sim Verilog HDL Function 16.6.11.3. ebfm_log_set_suppressed_msg_mask Task 16.6.11.4. ebfm_log_set_stop_on_msg_mask Verilog HDL Task 16.6.11.5. ebfm_log_open Verilog HDL Function 16.6.11.6. ebfm_log_close Verilog HDL Function
16.6.12. Verilog HDL Formatting Functions x
16.6.12.1. himage1 16.6.12.2. himage2 16.6.12.3. himage4 16.6.12.4. himage8 16.6.12.5. himage16 16.6.12.6. dimage1 16.6.12.7. dimage2 16.6.12.8. dimage3 16.6.12.9. dimage4 16.6.12.10. dimage5 16.6.12.11. dimage6 16.6.12.12. dimage7
16.7. Setting Up Simulation x
16.7.1. Changing Between Serial and PIPE Simulation 16.7.2. Using the PIPE Interface for Gen1 and Gen2 Variants 16.7.3. Viewing the Important PIPE Interface Signals 16.7.4. Disabling the Scrambler for Gen1 and Gen2 Simulations 16.7.5. Disabling 8B/10B Encoding and Decoding for Gen1 and Gen2 Simulations 16.7.6. Changing between the Hard and Soft Reset Controller
17. Debugging x
17.1. Hardware Bring-Up Issues 17.2. Link Training 17.3. Use Third-Party PCIe Analyzer 17.4. BIOS Enumeration Issues
17.2. Link Training x
17.2.1. Debugging Link that Fails To Reach L0 17.2.2. Link Hangs in L0 State
C. Document Revision History x
C.1. Document Revision History Stratix V Avalon® -ST Interface for PCIe* Solutions User Guide
1. Datasheet
2. Getting Started with the Stratix V Hard IP for PCI Express
3. Getting Started with the Configuration Space Bypass Mode Qsys Example Design
4. Parameter Settings
5. Interfaces and Signal Descriptions
6. Registers
7. Interrupts
8. Error Handling
9. PCI Express Protocol Stack
10. Transaction Layer Protocol (TLP) Details
11. Throughput Optimization
12. Design Implementation
13. Additional Features
14. Hard IP Reconfiguration
15. Transceiver PHY IP Reconfiguration
16. Testbench and Design Example
17. Debugging
A. Frequently Asked Questions for PCI Express
B. Lane Initialization and Reversal
C. Document Revision History

11.2. Throughput of Non-Posted Reads

To support a high throughput for read data, you must analyze the overall delay from the time the Application Layer issues the read request until all of the completion data is returned. The Application Layer must be able to issue enough read requests, and the read completer must be capable of processing these read requests quickly enough (or at least offering enough non-posted header credits) to cover this delay.

However, much of the delay encountered in this loop is well outside the IP core and is very difficult to estimate. PCI Express switches can be inserted in this loop, which makes determining a bound on the delay more difficult.

Nevertheless, maintaining maximum throughput of completion data packets is important. Endpoints must offer an infinite number of completion credits. Endpoints must buffer this data in the RX buffer until the Application Layer can process it. Because the Endpoint is no longer managing the RX buffer for Completions through the flow control mechanism, the Application Layer must manage the RX buffer by the rate at which it issues read requests.

To determine the appropriate settings for the amount of space to reserve for completions in the RX buffer, you must make an assumption about the length of time until read completions are returned. This assumption can be estimated in terms of an additional delay, beyond the FC Update Loop Delay, as discussed in the section Throughput of Posted Writes. The paths for the read requests and the completions are not exactly the same as those for the posted writes and FC Updates in the PCI Express logic. However, the delay differences are probably small compared with the inaccuracy in the estimate of the external read to completion delays.

With multiple completions, the number of available credits for completion headers must be larger than the completion data space divided by the maximum packet size. Instead, the credit space for headers must be the completion data space (in bytes) divided by 64, because this is the smallest possible read completion boundary. Setting the RX Buffer space allocation—Desired performance for received completions to High under the System Settings heading when specifying parameter settings configures the RX buffer with enough space to meet this requirement. You can adjust this setting up or down from the High setting to tailor the RX buffer size to your delays and required performance.

You can also control the maximum amount of outstanding read request data. This amount is limited by the number of header tag values that can be issued by the Application Layer and by the maximum read request size that can be issued. The number of header tag values that can be in use is also limited by the IP core. You can specify 32 or 64 tags though configuration software to restrict the Application Layer to use only 32 tags. In commercial PC systems, 32 tags are usually sufficient to maintain optimal read throughput.

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