
IDT Non-Transparent Mode Operation
PES16NT2 User Manual
10 - 3
April 15, 2008
Notes
Following configuration of the non-transparent bridge complex, the non-transparent bridge will appear
as a PCI-PCI bridge followed by an endpoint on the internal side and an endpoint on the external side.
Therefore, once configured the operation of the non-transparent bridge should be transparent to system
software and drivers. However, PCIe software that uses the PCI Express Capability structure may need to
be modified.
Transaction Routing
Transactions are routed by the port C PCI-PCI bridge in the same manner as in transparent mode.
Thus, the issue of transaction routing relates to how transactions are routed between the internal and
external endpoints associated with the non-transparent bridge.
PCIe defines the following transactions routing mechanisms.
–
Address routing with 32-bit or 64-bit format
–
ID based routing using bus, device and function numbers.
–
Implicit routing utilizing
Route to root
Broadcast from root
Local - terminate at receiver
Gathered and routed to root
No messages are passed through the non-transparent bridge. If a message is received by an internal or
external non-transparent endpoint that does not correspond to a message that should be processed by an
endpoint, then the message is silently discarded.
Address Routing
Address routed transactions consist of those that require completions (i.e., non-posted transactions)
and those that do not require completions (i.e., posted transactions). The behavior of posted transactions is
discussed first since their behavior is a subset of non-posted transactions.
Mapping Table
Associated with the internal and external endpoints of the NTB are 16-entry mapping tables. The
mapping table contains the bus, device and function numbers of initiators on that side of the NTB whose
transactions may be forwarded to the opposite side of the NTB. The format of these tables is shown in
Figure 10.2 and described in Table 10.1.
Figure 10.2 Internal and External Endpoint Non-Transparent Bridge Mapping Table Format
31
Mapping Table Entry Address 0
...
30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
V
BUS
DEV
FUNC
Mapping Table Entry Address 1
V
BUS
DEV
FUNC
Reserved
Reserved
Mapping Table Entry Address 2
V
BUS
DEV
FUNC
Mapping Table Entry Address 3
V
BUS
DEV
FUNC
Reserved
Reserved
Mapping Table Entry Address 14
V
BUS
DEV
FUNC
Mapping Table Entry Address 15
V
BUS
DEV
FUNC
Reserved
Reserved
...
...
...
Содержание 89HPES16NT2
Страница 14: ...DT List of Figures PES16NT2 User Manual viii April 15 2008 Notes...
Страница 20: ...IDT Register List PES16NT2 User Manual xiv April 15 2008 Notes...
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Страница 284: ...IDT Non Transparent Mode Operation PES16NT2 User Manual 10 154 April 15 2008 Notes...