Datasheet
Intel
®
Xeon
®
Processor C5500/C3500 Series
February 2010 Datasheet, Volume 1
Order Number: 323103-001 165
PCI Express Non-Transparent Bridge
3.10.3 Traffic Class
The IIO does not optimize based on traffic class. The IIO can receive a packet with
TC!= 0 and treat the packet as if it were TC = 0 from an ordering perspective. IIO
forwards the TC filed as is on peer-to-peer requests and also returns the TC field from
the original request on the completion packet sent back to the device.
3.11 Completer ID
The Completer ID field is used in PCI Express completion packets to identify the
completer of the transaction. The CompleterID comprises three sub-fields described in
Table 87.
3.12 Initialization
This section documents the initialization flow for the different usage models.
3.12.1 Initialization Sequence with NTB Ports Connected Back-to-Back
(NTB/NTB)
This usage model is discussed in Section 3.5.1. In this configuration, the secondary
side of one NTB is connected to the secondary side of another NTB.
Note: This section assumes that BAR sizes have already been defined per Section 3.12,
“Initialization” and crosslink configuration has been completed (if required). See
Section 3.6.3, “Crosslink Configuration” .
BIOS executing on the local host (the on-die core) on each system writes the primary
and secondary side NTB BAR sizes and PPD from the FWH or CMOS.
Enumeration SW reads the BARs and then sets the BAR locations in system memory.
Run time OS will configure the primary and secondary limit registers and primary and
secondary address translation registers of the NTB. See Section 3.6.4, “B2B BAR and
Translate Setup” .
The PCIE links attempt to initialize and train.
Once the links are trained, higher level software or the NTB device driver configures the
remote host interface of the NTB on both systems and enables the connectivity
between the two systems.
The advantage of this system is that connecting the NTB ports back-to-back has the
following advantages.
• BIOS on both systems can be identical. The BIOS configures both the local and
remote host interface of the NTB without requiring link training to complete.
Table 87. PCI Express CompleterID Handling
Field Definition IIO as Completer
Bus Number
Specifies the bus number that the
completer resides on.
The IIO fills this field in with its internal Bus
Number that the PCI Express cluster resides
on
Device Number
Specifies the device number of the
completer.
Device number of the root port sending the
completion back to PCIE.
Function
Number
Specifies the function number of the
completer.
0