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1. Datasheet
2. Quick Start Guide
3. Intel® Arria® 10 or Intel® Cyclone® 10 GX Parameter Settings
4. Physical Layout
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. Testbench and Design Example
16. Debugging
A. Transaction Layer Packet (TLP) Header Formats
B. Lane Initialization and Reversal
C. Intel® Arria® 10 or Intel® Cyclone® 10 GX Avalon-ST Interface for PCIe Solutions User Guide Archive
D. Document Revision History
1.1. Intel® Arria® 10 or Intel® Cyclone® 10 GX Avalon-ST Interface for PCI Express* Datasheet
1.2. Release Information
1.3. Device Family Support
1.4. Configurations
1.5. Debug Features
1.6. IP Core Verification
1.7. Resource Utilization
1.8. Recommended Speed Grades
1.9. Creating a Design for PCI Express
3.1. Parameters
3.2. Intel® Arria® 10 or Intel® Cyclone® 10 GX Avalon-ST Settings
3.3. Base Address Register (BAR) and Expansion ROM Settings
3.4. Base and Limit Registers for Root Ports
3.5. Device Identification Registers
3.6. PCI Express and PCI Capabilities Parameters
3.7. Vendor Specific Extended Capability (VSEC)
3.8. Configuration, Debug, and Extension Options
3.9. PHY Characteristics
3.10. Example Designs
4.1. Hard IP Block Placement In Intel® Cyclone® 10 GX Devices
4.2. Hard IP Block Placement In Intel® 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
5.1. 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. Parity Signals
5.9. LMI Signals
5.10. Transaction Layer Configuration Space Signals
5.11. Hard IP Reconfiguration Interface
5.12. Power Management Signals
5.13. Physical Layer Interface Signals
15.4.1. ebfm_barwr Procedure
15.4.2. ebfm_barwr_imm Procedure
15.4.3. ebfm_barrd_wait Procedure
15.4.4. ebfm_barrd_nowt Procedure
15.4.5. ebfm_cfgwr_imm_wait Procedure
15.4.6. ebfm_cfgwr_imm_nowt Procedure
15.4.7. ebfm_cfgrd_wait Procedure
15.4.8. ebfm_cfgrd_nowt Procedure
15.4.9. BFM Configuration Procedures
15.4.10. BFM Shared Memory Access Procedures
15.4.11. BFM Log and Message Procedures
15.4.12. Verilog HDL Formatting Functions
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10.3.1. Using Relaxed Ordering
Transactions from unrelated threads are unlikely to have data dependencies. Consequently, you may be able to use relaxed ordering to improve system performance. The drawback is that only some transactions can be optimized for performance. Complete the following steps to decide whether to enable relaxed ordering in your design:
- Create a system diagram showing all PCI Express and legacy devices.
- Analyze the relationships between the components in your design to identify the following hazards:
- Race conditions: A race condition exists if a read to a location can occur before a previous write to that location completes. The following figure shows a data producer and data consumer on opposite sides of a PCI-to-PCI bridge. The producer writes data to the memory through a PCI-to-PCI bridge. The consumer must read a flag to confirm the producer has written the new data into the memory before reading the data. However, because the PCI-to-PCI bridge includes a write buffer, the flag may indicate that it is safe to read data while the actual data remains in the PCI-to-PCI bridge posted write buffer.
Figure 63. Design Including Legacy PCI Buses Requiring Strong Ordering
- A shared memory architecture where more than one thread accesses the same locations in memory.
If either of these conditions exists, relaxed ordering leads to incorrect results.
- Race conditions: A race condition exists if a read to a location can occur before a previous write to that location completes. The following figure shows a data producer and data consumer on opposite sides of a PCI-to-PCI bridge. The producer writes data to the memory through a PCI-to-PCI bridge. The consumer must read a flag to confirm the producer has written the new data into the memory before reading the data. However, because the PCI-to-PCI bridge includes a write buffer, the flag may indicate that it is safe to read data while the actual data remains in the PCI-to-PCI bridge posted write buffer.
- If your analysis determines that relaxed ordering does not lead to possible race conditions or read or write hazards, you can enable relaxed ordering by setting the RO bit in the TLP header.
- The following figure shows two PCIe Endpoints and Legacy Endpoint connected to a switch. The three PCIe Endpoints are not likely to have data dependencies. Consequently, it would be safe to set the relaxed ordering bit for devices connected to the switch. In this system, if relax ordering is not enabled, a memory read to the legacy Endpoint is blocked. The legacy Endpoint read is blocked because an earlier posted write cannot be completed as the write buffer is full. .
Figure 64. PCI Express Design Using Relaxed Ordering
- If your analysis indicates that you can enable relaxed ordering, simulate your system with and without relaxed ordering enabled. Compare the results and performance.
- If relaxed ordering improves performance without introducing errors, you can enable it in your system.