Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
243
Address Translation Unit (PCI Express)—Intel
®
81341 and 81342
The ATU uses the following registers in inbound address window 1 translation:
•
Section 3.16.16, “Inbound ATU Base Address Register 1 - IABAR1” on page 312
• Section 3.16.31, “Inbound ATU Limit Register 1 - IALR1” on page 324
•
Section 3.16.32, “Inbound ATU Translate Value Register 1 - IATVR1” on page 325
•
Section 3.16.33, “Inbound ATU Upper Translate Value Register 1 - IAUTVR1” on
The ATU uses the following registers in inbound address window 2 translation:
•
Section 3.16.18, “Inbound ATU Base Address Register 2 - IABAR2” on page 314
• Section 3.16.34, “Inbound ATU Limit Register 2 - IALR2” on page 326
•
Section 3.16.35, “Inbound ATU Translate Value Register 2 - IATVR2” on page 327
•
Section 3.16.36, “Inbound ATU Upper Translate Value Register 2 - IAUTVR2” on
Inbound address detection is determined by comparing the 64-bit PCI address with the
base address register and the limit register. In the case of 3DW headers, the upper 32-
bits of the address is assumed to be 0000_0000h during address comparison. The
algorithm for detection is:
shows an example of inbound address detection.
The lower 32-bits of the incoming address is bitwise ANDed with the associated
inbound limit register. When the result matches the base register, the inbound PCI
address is detected as being within the inbound translation window and is claimed by
the ATU. When the address is outside the translation window, the ATU terminates the
transaction as an Unsupported Request (UR).
Note:
By default, the first 8Kbytes of the ATU inbound address translation window 0 are
reserved for the Messaging Unit. See
Section 3.5, “Messaging Unit” on page 261
.
Equation 8. Inbound Address Detection
When PCI_Address [31:0] & Limit_Register[31:0] == Base_Register[31:0] and
PCI_Address [63:32] == Base_Register[63:32] the PCI Address is translated by the Inbound ATU.
Otherwise treat as an Unsupported Request.
Figure 25. Inbound Address Detection
PCI Address
Space
Base_Register
Base_Re Value of Limit_Register
Inbound
Translation
Window
Address is claimed
Address is not claimed
Unsupported Request
Address is not claimed
Unsupported Request
B6334-01