February, 2007
Intelligent Adapter Mode
4.4.1
Intelligent Adapter Mode
The use of Non-Transparent bridges in PCI systems is well established for supporting intelligent
adapters in enterprise and multi-host systems. The same concept is used in PCI Express bridges
and switches.
In Figure 4-7, there are two Type 0 CSR headers in the Non-Transparent PCI-to-PCI bridge. The one
nearer the internal virtual bus is referred to as the Virtual Interface. The one nearer the PCI Express link
is referred to as the Link Interface.
In Intelligent Adapter mode, the NT Port Link Interface is connected to the System domain. The System
Host manages only the NT Port Link Interface Type 0 function. The Local Host manages all PEX 8532
Transparent Port Type 1 and NT Port Virtual Interface Type 0 functions. Cross-domain traffic is routed
through an Address Translation mechanism. (Refer to Section 12.1.6, “Address Translation.”)
After power-up, the PEX 8532 Non-Transparent Type 1 ports, including the NT Port Virtual Interface,
are enumerated by the Local Host connected to the PEX 8532 upstream port. The Local Host enables
and resizes the Base Address registers (BARs) by programming the NT Port Link Interface BAR
Setup/Limit registers, before the System Host assigns resources for these BARs. This behavior is
changed with serial EEPROM initialization.
After the Local Host finishes its enumeration, it enables the NT Port Link Interface to be enumerated by
the System Host connected to the interface. The NT Port Link Interface Retries the System Host
Configuration transaction until the Local Host enables the NT Port Link Interface to process the System
Host Configuration transaction. The Debug Control register Virtual Interface Access Enable bit
(offset 1DCh[28]) enables access to the Virtual Interface Configuration registers. The Link Interface
Access Enable bit (offset 1DCh[29]) enables access to the Link Interface Configuration registers.
These bits do not affect normal Memory, Memory-Mapped CSRs, nor I/O-Mapped CSR transactions.
Intelligent Adapter mode does not support Host-Failover applications.
Figure 4-7. PEX 8532 Intelligent Adapter Software Model
Fabric/
System Host
Local Host
I/O Fabric
Non-Transparent
Upstream Port
PEX 8532
Transparent
Upstream Port
Link Interface
Primary
Transparent
Upstream
P-P Bridge
P-P Bridge
CSR / BAR
CSR
BAR
Non-Transparent
Downstream
P-P Bridge
Address Translation
CSR / BAR
Virtual Interface
Transparent
Downstream
P-P Bridges
P-P
P-P
P-P
Transparent
Downstream Ports
ExpressLane PEX 8532AA/BA/BB/BC 8-Port/32-Lane Versatile PCI Express Switch Data Book
Copyright © 2007 by PLX Technology, Inc. All Rights Reserved – Version 1.6
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