Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
269
Address Translation Unit (PCI Express)—Intel
®
81341 and 81342
Definitions of the terms used in
and
are as follows. PCI terms are
noted in parenthesis:
These transaction ordering rules define the way in which data moves in both directions
through the ATU. In
NO
response in a box means that based
on ordering rules, the current transaction (the row) can not pass the previous
transaction (the column) under any circumstance. A
Yes
response in the box means
that the current transaction is allowed to pass the previous transaction but is not
required to, based on whether a consistent view of data or prevention of deadlocks are
needed.
In the case of inbound write operations, multiple transactions may exist within the
IPHQ and the corresponding IPDQ at any point in time. The ordering of these
transactions is based on a time stamp basis. Transactions entering the queue are
stamped with a relative time in relation to all other transactions moving in a similar
direction.
Table 126. ATU Outbound Data Flow Ordering Rules
Row Pass Column?
Outbound
Write or
Message
Request
Outbound
Read
Request
Outbound
Configuratio
n Write
Request
Outbound
Read
Completion
Outbound
Configuratio
n or I/O
Write
Completion
Outbound Write or
Message Request
No
Yes
Yes
Yes
Yes
Outbound Read Request
No
No
No
Yes
Yes
Outbound Configuration
Write Request
No
No
No
Yes
Yes
Outbound Read
Completion
No
Yes
Yes
Yes
Yes
Outbound Configuration
or I/O Write Completion
No
Yes
Yes
Yes
Yes
Example 5. Inbound Queue Completion
A6499-01
Outbound Read Queue
B
B
B
B
B
B
B
B
Inbound Write Queue
C
C
C
C
C
C
C
C
A
A
A
A
A
A
A
Outbound Read Queue
B
B
B
B
B
B
B
B
Inbound Write Queue
C
C
C
C
C
C
C
C
PCI Bus
Internal Bus