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

10.3. Receive Buffer Reordering

The PCI, PCI-X and PCI Express protocols include ordering rules for concurrent TLPs. Ordering rules are necessary for the following reasons:

  • To guarantee that TLPs complete in the intended order
  • To avoid deadlock
  • To maintain computability with ordering used on legacy buses
  • To maximize performance and throughput by minimizing read latencies and managing read/write ordering
  • To avoid race conditions in systems that include legacy PCI buses by guaranteeing that reads to an address do not complete before an earlier write to the same address

PCI uses a strongly-ordered model with some exceptions to avoid potential deadlock conditions. PCI-X added a relaxed ordering (RO) bit in the TLP header. It is bit 5 of byte 2 in the TLP header, or the high-order bit of the attributes field in the TLP header. If this bit is set, relaxed ordering is permitted. If software can guarantee that no dependencies exist between pending transactions, you can safely set the relaxed ordering bit.

The following table summarizes the ordering rules from the PCI specification. In this table, the entries have the following meanings:

  • Columns represent the first transaction issued.
  • Rows represent the next transaction.
  • At each intersection, the implicit question is: should this row packet be allowed to pass the column packet? The following three answers are possible:
    • Yes: the second transaction must be allowed to pass the first to avoid deadlock.
    • Y/N: There are no requirements. A device may allow the second transaction to pass the first.
    • No: The second transaction must not be allowed to pass the first.

The following transaction ordering rules apply to the table below.

  • A Memory Write or Message Request with the Relaxed Ordering Attribute bit clear (b’0) must not pass any other Memory Write or Message Request.
  • A Memory Write or Message Request with the Relaxed Ordering Attribute bit set (b’1) is permitted to pass any other Memory Write or Message Request.
  • Endpoints, Switches, and Root Complex may allow Memory Write and Message Requests to pass Completions or be blocked by Completions.
  • Memory Write and Message Requests can pass Completions traveling in the PCI Express to PCI directions to avoid deadlock.
  • If the Relaxed Ordering attribute is not set, then a Read Completion cannot pass a previously enqueued Memory Write or Message Request.
  • If the Relaxed Ordering attribute is set, then a Read Completion is permitted to pass a previously enqueued Memory Write or Message Request.
  • Read Completion associated with different Read Requests are allowed to be blocked by or to pass each other.
  • Read Completions for Request (same Transaction ID) must return in address order.
  • Non-posted requests cannot pass other non-posted requests.
  • CfgRd0CfgRd0 can pass IORd or MRd.
  • CfgWr0 can IORd or MRd.
  • CfgRd0 can pass IORd or MRd.
  • CfrWr0 can pass IOWr.
Table 75.  Transaction Ordering Rules

Can the Row Pass the Column?

Posted Req

Non Posted Req

Completion

Memory Write or Message Req

Read Request

I/O or Cfg Write Req

Spec

Hard IP

Spec

Hard IP

Spec

Hard IP

Spec

Hard IP

P

Posted Req

No

Y/N

No

No

Yes

Yes

Yes

Yes

Y/N

Yes

No

No

NP

Read Req

No

No

Y/N

No

Y/N

No

Y/N

No

Non-Posted Req with data

No

No

Y/N

No

Y/N

No

Y/N

No

Cmpl

Cmpl

No

Y/N

No

No

Yes

Yes

Yes

Yes

Y/N

No

No

No

I/O or Configuration Write Cmpl

Y/N

No

Yes

Yes

Yes

Yes

Y/N

No

As the table above indicates, the RX datapath implements an RX buffer reordering function that allows Posted and Completion transactions to pass Non-Posted transactions (as allowed by PCI Express ordering rules) when the Application Layer is unable to accept additional Non-Posted transactions.

The Application Layer dynamically enables the RX buffer reordering by asserting the rx_mask signal. The rx_mask signal blocks non-posted Req transactions made to the Application Layer interface so that only posted and completion transactions are presented to the Application Layer.

Note: MSI requests are conveyed in exactly the same manner as PCI Express memory write requests and are indistinguishable from them in terms of flow control, ordering, and data integrity.

Section Content
Using Relaxed Ordering

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