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Datasheet 11
Introduction
1.3.2 PCI Express*
• The PCI Express* port(s) are fully-compliant with the PCI Express* Base
Specification, Revision 3.0 (PCIe 3.0)
• Support for PCI Express* 3.0 (8.0 GT/s), 2.0 (5.0 GT/s), and 1.0 (2.5 GT/s)
• Up to 40 lanes of PCI Express* interconnect for general purpose PCI Express*
devices at PCIe* 3.0 speeds that are configurable for up to 10 independent ports
• 4 lanes of PCI Express* at PCIe* 2.0 speeds when not using DMI2 port (Port 0),
also can be downgraded to x2 or x1
• Negotiating down to narrower widths is supported, see Figure 1-2:
— x16 port (Port 2 and Port 3) may negotiate down to x8, x4, x2, or x1
— x8 port (Port 1) may negotiate down to x4, x2, or x1
— x4 port (Port 0) may negotiate down to x2, or x1
— When negotiating down to narrower widths, there are caveats as to how lane
reversal is supported
• Address Translation Services (ATS) 1.0 support
• Hierarchical PCI-compliant configuration mechanism for downstream devices
• Traditional PCI style traffic (asynchronous snooped, PCI ordering)
• PCI Express* extended configuration space. The first 256 bytes of configuration
space aliases directly to the PCI compatibility configuration space. The remaining
portion of the fixed 4-KB block of memory-mapped space above that (starting at
100h) is known as extended configuration space.
• PCI Express* Enhanced Access Mechanism – accessing the device configuration
space in a flat memory mapped fashion
• Automatic discovery, negotiation, and training of link out of reset
• Supports receiving and decoding 64 bits of address from PCI Express*:
— Memory transactions received from PCI Express* that go above the top of
physical address space (when Intel VT-d is enabled, the check would be against
the translated Host Physical Address (HPA)) are reported as errors by the
processor.
— Outbound access to PCI Express* will always have address bits 63:46 cleared
• Re-issues Configuration cycles that have been previously completed with the
Configuration Retry status
• Power Management Event (PME) functions
• Message Signaled Interrupt (MSI and MSI-X) messages
• Degraded Mode support and Lane Reversal support
• Static lane numbering reversal and polarity inversion support
• Support for PCIe* 3.0 atomic operation, PCIe 3.0 optional extension on atomic
read-modify-write mechanism