Arria® 10 and Cyclone® 10 GX Avalon® Memory-Mapped (Avalon-MM) Interface for PCI Express* User Guide

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ID 683724
Date 9/10/2024
Public
Document Table of Contents
Document Table of Contents x
1. Datasheet 2. Quick Start Guide 3. Parameter Settings 4. Physical Layout 5. 64- or 128-Bit Avalon-MM Interface to the Endpoint Application Layer 6. Registers 7. Reset and Clocks 8. Interrupts for Endpoints 9. Error Handling 10. Design Implementation 11. Throughput Optimization 12. Additional Features 13. Avalon-MM Testbench and Design Example 14. Avalon-MM Testbench and Design Example for Root Port 15. Hard IP Reconfiguration 16. Debugging A. PCI Express Protocol Stack B. Transaction Layer Packet (TLP) Header Formats C. Lane Initialization and Reversal D. Arria® 10 or Cyclone® 10 GX Avalon® -MM Interface for PCIe* Solutions User Guide Archive E. Document Revision History
1. Datasheet x
1.1. Arria® 10 or Cyclone® 10 GX 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. Quick Start Guide x
2.1. Directory Structure 2.2. Design Components for the Avalon® -MM Endpoint 2.3. Generating the Design 2.4. Simulating the Design 2.5. Compiling and Testing the Design in Hardware
3. Parameter Settings x
3.1. Parameters 3.2. Avalon-MM Settings 3.3. Base Address Register (BAR) Settings 3.4. Device Identification Registers 3.5. PCI Express and PCI Capabilities Parameters 3.6. Configuration, Debug, and Extension Options 3.7. Vendor Specific Extended Capability (VSEC) 3.8. PHY Characteristics 3.9. Example Designs
3.5. PCI Express and PCI Capabilities Parameters x
3.5.1. Device Capabilities 3.5.2. Error Reporting 3.5.3. Link Capabilities 3.5.4. MSI and MSI-X Capabilities 3.5.5. Slot Capabilities 3.5.6. Power Management
4. Physical Layout x
4.1. Hard IP Block Placement In Cyclone® 10 GX Devices 4.2. Hard IP Block Placement In Arria® 10 Devices 4.3. Channel and Pin Placement for the Gen1, Gen2, and Gen3 Data Rates 4.4. Channel Placement and fPLL and ATX PLL Usage for the Gen3 Data Rate 4.5. PCI Express Gen3 Bank Usage Restrictions
5. 64- or 128-Bit Avalon-MM Interface to the Endpoint Application Layer x
5.1. 32-Bit Non-Bursting Avalon-MM Control Register Access (CRA) Slave Signals 5.2. Bursting and Non-Bursting Avalon® -MM Module Signals 5.3. 64- or 128-Bit Bursting TX Avalon-MM Slave Signals 5.4. Clock Signals 5.5. Reset, Status, and Link Training Signals 5.6. Interrupts for Endpoints when Multiple MSI/MSI-X Support Is Enabled 5.7. Hard IP Status Signals 5.8. Physical Layer Interface Signals
5.7. Hard IP Status Signals x
5.7.1. Hard IP Reconfiguration Interface
5.8. Physical Layer Interface Signals x
5.8.1. Serial Data Signals 5.8.2. PIPE Interface Signals 5.8.3. Arria® 10 Development Kit Conduit Interface 5.8.4. Test Signals
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. 64- or 128-Bit Avalon-MM Bridge Register Descriptions 6.8. Programming Model for Avalon-MM Root Port 6.9. Uncorrectable Internal Error Mask Register 6.10. Uncorrectable Internal Error Status Register 6.11. Correctable Internal Error Mask Register 6.12. Correctable Internal Error Status Register
6.7. 64- or 128-Bit Avalon-MM Bridge Register Descriptions x
6.7.1. Avalon-MM to PCI Express Interrupt Registers
6.7.1. Avalon-MM to PCI Express Interrupt Registers x
6.7.1.1. Avalon-MM to PCI Express Interrupt Status Registers 6.7.1.2. Avalon-MM to PCI Express Interrupt Enable Registers 6.7.1.3. PCI Express Mailbox Registers 6.7.1.4. Avalon-MM-to-PCI Express Address Translation Table 6.7.1.5. PCI Express to Avalon-MM Interrupt Status and Enable Registers for Endpoints 6.7.1.6. Avalon-MM Mailbox Registers 6.7.1.7. Control Register Access (CRA) Avalon-MM Slave Port
6.8. Programming Model for Avalon-MM Root Port x
6.8.1. Sending a Write TLP 6.8.2. Sending a Read TLP or Receiving a Non-Posted Completion TLP 6.8.3. Examples of Reading and Writing BAR0 Using the CRA Interface 6.8.4. PCI Express to Avalon-MM Interrupt Status and Enable Registers for Root Ports 6.8.5. Root Port TLP Data Registers
7. Reset and Clocks x
7.1. Reset Sequence for Hard IP for PCI Express IP Core and Application Layer 7.2. Clocks
7.2. Clocks x
7.2.1. Clock Domains 7.2.2. Clock Summary
7.2.1. Clock Domains x
7.2.1.1. coreclkout_hip 7.2.1.2. pld_clk
8. Interrupts for Endpoints x
8.1. Enabling MSI or Legacy Interrupts 8.2. Generation of Avalon-MM Interrupts 8.3. Interrupts for Endpoints Using the Avalon-MM Interface with Multiple MSI/MSI-X Support
9. Error Handling x
9.1. Physical Layer Errors 9.2. Data Link Layer Errors 9.3. Transaction Layer Errors 9.4. Error Reporting and Data Poisoning 9.5. Uncorrectable and Correctable Error Status Bits
10. Design Implementation x
10.1. Making Pin Assignments to Assign I/O Standard to Serial Data Pins 10.2. Recommended Reset Sequence to Avoid Link Training Issues 10.3. SDC Timing Constraints
11. Throughput Optimization x
11.1. Throughput of Posted Writes 11.2. Throughput of Non-Posted Reads
12. Additional Features x
12.1. Configuration over Protocol (CvP) 12.2. Autonomous Mode 12.3. ECRC
12.2. Autonomous Mode x
12.2.1. Enabling Autonomous Mode 12.2.2. Enabling CvP Initialization
12.3. ECRC x
12.3.1. ECRC on the RX Path 12.3.2. ECRC on the TX Path
13. Avalon-MM Testbench and Design Example x
13.1. Avalon-MM Endpoint Testbench 13.2. Endpoint Design Example 13.3. Avalon-MM Test Driver Module 13.4. Root Port BFM 13.5. BFM Procedures and Functions 13.6. Setting Up Simulation
13.2. Endpoint Design Example x
13.2.1. BAR/Address Map 13.2.2. BAR Setup
13.4. Root Port BFM x
13.4.1. Root Port BFM Overview 13.4.2. Issuing Read and Write Transactions to the Application Layer 13.4.3. Configuration of Root Port and Endpoint 13.4.4. Configuration Space Bus and Device Numbering 13.4.5. BFM Memory Map
13.5. BFM Procedures and Functions x
13.5.1. ebfm_barwr Procedure 13.5.2. ebfm_barwr_imm Procedure 13.5.3. ebfm_barrd_wait Procedure 13.5.4. ebfm_barrd_nowt Procedure 13.5.5. ebfm_cfgwr_imm_wait Procedure 13.5.6. ebfm_cfgwr_imm_nowt Procedure 13.5.7. ebfm_cfgrd_wait Procedure 13.5.8. ebfm_cfgrd_nowt Procedure 13.5.9. BFM Configuration Procedures 13.5.10. BFM Shared Memory Access Procedures 13.5.11. BFM Log and Message Procedures 13.5.12. Verilog HDL Formatting Functions
13.5.9. BFM Configuration Procedures x
13.5.9.1. ebfm_cfg_rp_ep Procedure 13.5.9.2. ebfm_cfg_decode_bar Procedure
13.5.10. BFM Shared Memory Access Procedures x
13.5.10.1. Shared Memory Constants 13.5.10.2. shmem_write Task 13.5.10.3. shmem_read Function 13.5.10.4. shmem_display Verilog HDL Function 13.5.10.5. shmem_fill Procedure 13.5.10.6. shmem_chk_ok Function
13.5.11. BFM Log and Message Procedures x
13.5.11.1. ebfm_display Verilog HDL Function 13.5.11.2. ebfm_log_stop_sim Verilog HDL Function 13.5.11.3. ebfm_log_set_suppressed_msg_mask Task 13.5.11.4. ebfm_log_set_stop_on_msg_mask Verilog HDL Task 13.5.11.5. ebfm_log_open Verilog HDL Function 13.5.11.6. ebfm_log_close Verilog HDL Function
13.5.12. Verilog HDL Formatting Functions x
13.5.12.1. himage1 13.5.12.2. himage2 13.5.12.3. himage4 13.5.12.4. himage8 13.5.12.5. himage16 13.5.12.6. dimage1 13.5.12.7. dimage2 13.5.12.8. dimage3 13.5.12.9. dimage4 13.5.12.10. dimage5 13.5.12.11. dimage6 13.5.12.12. dimage7
13.6. Setting Up Simulation x
13.6.1. Using the PIPE Interface for Gen1 and Gen2 Variants 13.6.2. Viewing the Important PIPE Interface Signals 13.6.3. Disabling the Scrambler for Gen1 and Gen2 Simulations 13.6.4. Disabling 8B/10B Encoding and Decoding for Gen1 and Gen2 Simulations
14. Avalon-MM Testbench and Design Example for Root Port x
14.1. Overview of the Design Example 14.2. Overview of the Simulation Testbench
14.1. Overview of the Design Example x
14.1.1. Example Design Generation 14.1.2. Directory Structure for the Generated Design Example
14.2. Overview of the Simulation Testbench x
14.2.1. Simulating the Design Example
15. Hard IP Reconfiguration x
15.1. Reconfigurable Read-Only Registers in the Hard IP for PCI Express
16. Debugging x
16.1. Simulation Fails To Progress Beyond Polling.Active State 16.2. Hardware Bring-Up Issues 16.3. Link Training 16.4. Creating a Signal Tap Debug File to Match Your Design Hierarchy 16.5. Use Third-Party PCIe Analyzer 16.6. BIOS Enumeration Issues
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. Interrupts A.1.4. 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 A.5.5. Preliminary Support for Root Port
B. Transaction Layer Packet (TLP) Header Formats x
B.1. TLP Packet Formats without Data Payload B.2. TLP Packet Formats with Data Payload
E. Document Revision History x
E.1. Document Revision History for the Arria® 10 and Cyclone® 10 GX Avalon® Memory Mapped (Avalon-MM) Interface for PCIe* Solutions User Guide
1. Datasheet
2. Quick Start Guide
3. Parameter Settings
4. Physical Layout
5. 64- or 128-Bit Avalon-MM Interface to the Endpoint Application Layer
6. Registers
7. Reset and Clocks
8. Interrupts for Endpoints
9. Error Handling
10. Design Implementation
11. Throughput Optimization
12. Additional Features
13. Avalon-MM Testbench and Design Example
14. Avalon-MM Testbench and Design Example for Root Port
15. Hard IP Reconfiguration
16. Debugging
A. PCI Express Protocol Stack
B. Transaction Layer Packet (TLP) Header Formats
C. Lane Initialization and Reversal
D. Arria® 10 or Cyclone® 10 GX Avalon® -MM Interface for PCIe* Solutions User Guide Archive
E. Document Revision History

11. Throughput Optimization

The PCI Express Base Specification defines a flow control mechanism to ensure efficient transfer of TLPs.

Each transmitter, the write requester in this case, maintains a credit limit register and a credits consumed register. The credit limit register is the sum of all credits received by the receiver, the write completer in this case. The credit limit register is initialized during the flow control initialization phase of link initialization and then updated during operation by Flow Control (FC) Update DLLPs. The credits consumed register is the sum of all credits consumed by packets transmitted. Separate credit limit and credits consumed registers exist for each of the six types of Flow Control:

  • Posted Headers
  • Posted Data
  • Non-Posted Headers
  • Non-Posted Data
  • Completion Headers
  • Completion Data

Each receiver also maintains a credit allocated counter which is initialized to the total available space in the RX buffer (for the specific Flow Control class) and then incremented as packets are pulled out of the RX buffer by the Application Layer. The value of this register is sent as the FC Update DLLP value.

Figure 54. Flow Control Update Loop

The PCIe Hard IP maintains its own flow control logic, including a credit consumed register, and ensures that no TLP is sent that would use more credits than are available for that type of TLP. If you want optimum performance and granularity, you can maintain your own credit consumed register and flow control gating logic for each credit category (Header/Data, Posted/Non-posted/Completion). This allows you to halt the transmission of TLPs for a category that is out of credits, while still allowing TLP transmission for categories that have sufficient credits.

The following steps describe the Flow Control Update loop. The corresponding numbers in the figure show the general area to which they correspond.

  1. When the Application Layer has a packet to transmit, the number of credits required is calculated. If the required credits are less than or equal to the current value of available credits (credit limit - credits consumed so far), then the packet can be transmitted immediately. However, if the credit limit minus credits consumed is less than the required credits, then the packet must be held until the credit limit is increased to a sufficient value by an FC Update DLLP. This check is performed separately for the header and data credits; a single packet consumes only a single header credit.
  2. After the packet is selected for transmission the credits consumed register is incremented by the number of credits consumed by this packet. This increment happens for both the header and data credit consumed registers.
  3. The packet is received at the other end of the link and placed in the RX buffer.
  4. At some point the packet is read out of the RX buffer by the Application Layer. After the entire packet is read out of the RX buffer, the credit allocated register can be incremented by the number of credits the packet has used. There are separate credit allocated registers for the header and data credits.
  5. The value in the credit allocated register is used to create an FC Update DLLP.
  6. After an FC Update DLLP is created, it arbitrates for access to the PCI Express link. The FC Update DLLPs are typically scheduled with a low priority; consequently, a continuous stream of Application Layer TLPs or other DLLPs (such as ACKs) can delay the FC Update DLLP for a long time. To prevent starving the attached transmitter, FC Update DLLPs are raised to a high priority under the following three circumstances:
    1. When the last sent credit allocated counter minus the amount of received data is less than MAX_PAYLOAD and the current credit allocated counter is greater than the last sent credit counter. Essentially, this means the data sink knows the data source has less than a full MAX_PAYLOAD worth of credits, and therefore is starving.
    2. When an internal timer expires from the time the last FC Update DLLP was sent, which is configured to 30 µs to meet the PCI Express Base Specification for resending FC Update DLLPs.
    3. When the credit allocated counter minus the last sent credit allocated counter is greater than or equal to 25% of the total credits available in the RX buffer, then the FC Update DLLP request is raised to high priority.

      After arbitrating, the FC Update DLLP that won the arbitration to be the next item is transmitted. In the worst case, the FC Update DLLP may need to wait for a maximum sized TLP that is currently being transmitted to complete before it can be sent.

  7. The original write requester receives the FC Update DLLP. The credit limit value is updated. If packets are stalled waiting for credits, they can now be transmitted.
Note: You must keep track of the credits consumed by the Application Layer.

Section Content
Throughput of Posted Writes
Throughput of Non-Posted Reads

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