Datasheet

Intel
®
Xeon
®
Processor C5500/C3500 Series
February 2010 Datasheet, Volume 1
Order Number: 323103-001 155
PCI Express Non-Transparent Bridge
The offset to the base of the 4 GB window on the incoming address is preserved in the
translated address.
3.6.7 Requester ID Translation
Completions for non-posted transactions are routed using Requester ID instead of the
address. The NTB provides a mechanism to translate the Requester ID and the
Completer ID from one domain to the other.
The Requester ID consists of the Requester’s PCI bus number, device number and
function number. The completer ID consists of completer’s PCI bus number, device
number and function number
For Intel
®
Xeon
®
processor C5500/C3500 series NTB, the primary side of the NTB will
have a fixed Bus Device Function (BDF) which is BDF = 0,3,0. The BDF of the
secondary side of the NTB depends on the configuration selected.
If the configuration is NTB/NTB then the BDF of the secondary side of the NTB will be
defined by the Section 3.0, “PCI Express Non-Transparent Bridge” . This is because in
the NTB/NTB case no configuration transactions are sent across the link and the local
host associated with the NTB must setup both sides of the NTB. See Figure 57 for an
example of how Requester and Completer ID translation are handled by hardware.
Figure 57. NTB to NTB Read Request, ID translation Example
JSP
JSP
JSP
HOST A HOST A
HOST B HOST B
NTB A
NTB A
NTB B NTB B
RCiEP
BDF 030
RCiEP
BDF 030
RCiEP
BDF 030
RCiEP
BDF 030
PCIE EP
BDF 128,0,0
PCIE EP
BDF 128,0,0
PCIE EP
BDF 127,0,0
PCIE EP
BDF 127,0,0
MRd
Req ID 0,0,0
MRd
Req ID 128,0,0
MRd
Req ID 0,3,0
Cmpl
Req ID 0,3,0
Cmptr ID 0,0,0
Cmpl
Req ID 128,0,0
Cmptr ID 127,0,0
Cmpl
Req ID 0,0,0
Cmptr ID 0,3,0
Memory Read request from
HOST A to HOST B
NTB no mans land is defaulted
to BDF 127,0,0 upstream port
and BDF 128,0,0 downstream
port based on strap
Read
Request
Completion
JSP
BDF 000
BDF 000