Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
293
Address Translation Unit (PCI Express)—Intel
®
81341 and 81342
3.16
Register Definitions
Every PCI device implements its own separate configuration address space and
configuration registers. The PCI Express Specification extends the configuration space
to 4096 bytes as compared to 256 bytes allowed by PCI Local Bus Specification,
Revision 2.3. The ATU configuration space is divided into a PCI 2.3 compatible region
consisting of the first 256 bytes and an extended PCI express configuration space
region consisting of the remaining space. The PCI 2.3 compatible space provides
support for legacy operating systems. The first 64 bytes must adhere to a predefined
header format.
defines the header format.
shows the PCI configuration registers,
listed by internal bus address offset.
shows the entire ATU configuration
space (including header and extended registers) and the corresponding section that
describes each register. Note that all configuration read and write transactions is
accepted on the internal bus as 32-bit transactions. Refer to
The ATU is programmed via a Type 0 configuration command on the PCI interface. See
Section 3.3.1.5, “Inbound Configuration Cycle Translation (ID Routed)” on page 247
.
ATU configuration space is function number zero of the 81341 and 81342 single-
function PCI device.
Beyond the required 64 byte header format, ATU configuration space implements
extended register space in support of the units functionality. Refer to the PCI Express
Base Specification, Revision 1.0a for details on accessing and programming
configuration register space.
Figure 34. ATU Interface Configuration Header Format
ATU Device ID
Vendor ID
00H
Status
Command
04H
ATU Class Code
Revision ID
08H
ATUBISTR
Header Type
Latency Timer
Cacheline Size
0CH
Inbound ATU Base Address 0
10H
Inbound ATU Upper Base Address 0
14H
Inbound ATU Base Address 1
18H
Inbound ATU Upper Base Address 1
1CH
Inbound ATU Base Address 2
20H
Inbound ATU Upper Base Address 2
24H
Reserved
28H
ATU Subsystem ID
ATU Subsystem Vendor ID
2CH
Expansion ROM Base Address
30H
Reserved
Capabilities Pointer
34H
Reserved
38H
Maximum Latency
Minimum Grant
Interrupt Pin
Interrupt Line
3CH