
IDT Non-Transparent Switch Operation
PES32NT24xG2 User Manual
14 - 15
January 30, 2013
Notes
If the Completion No Snoop Processing (CNS) field in the NT Mapping entry corresponding to the
extracted NT Mapping table index (see section Completion ID Translation on page 14-13) is set, then the
No Snoop attribute in the translated TLP is inverted. If the CNS bit is cleared, then the No Snoop attribute in
the translated TLP is equal to that of the received completion TLP (i.e., the No Snoop attribute is not modi-
fied).
The NT function supports processing of the No Snoop attribute for request or completions TLPs that
cross the NTB. It also supports processing of the Address Type field for requests that cross the NTB.
The NT function does not support processing of the Relaxed Ordering attribute (i.e., this attribute is not
modified in TLPs that cross the NTB). Therefore, TLPs that cross the NTB and have the Relaxed Ordering
attribute set are understood to be relaxed ordered TLPs in both the source and destination partitions.
The Enable Relaxed Ordering (ERO) bit in the NT function’s PCI Express Device Control register
(PCIEDCTL) may be set or cleared by software, but it has no effect on the hardware. When this bit is
cleared by software, the user must ensure that no translated TLPs emitted by the NT function have the
Relaxed Ordering attribute set (i.e., TLPs received by an NT function in another partition and emitted by the
NT function whose ERO bit is cleared).
Address Type Processing
As described in the Address Translation Services Specification, March 8, 2007, PCI-SIG and the PCI
Express Base Specification Revision 2.1, the Address Type (AT) field in the header of a memory read or
memory write TLP indicates the type of address in the TLP (i.e., untranslated, translation request, trans-
lated).
The NT endpoint does not support Address Translation Services (ATS) as defined by the PCI-SIG, but it
has the ability to modify the AT field for TLPs that cross the NTB. This allows the NTB to receive TLPs with
translated addresses (i.e., AT field set to ‘translated’) in a source partition and emit them as TLPs with
translated or untranslated addresses in the destination partition, or vice-versa.
Address type processing is only applied to memory read or write TLPs whose AT field is set to ‘trans-
lated’ or ‘untranslated’. Address type processing is not applied to TLPs whose AT field is set to ‘translation
request’. Address type processing is performed based on the Address Type Processing (ATP) field in the
matching NT Mapping Table entry, or based on the ATP field in the NTCTL register when the ID Protection
Check Disable (IDPROTDIS) bit in the NTCTL register is set.
When an NT table lookup is performed for a request TLP (described in section Request ID Translation
on page 14-11), the Address Type Processing (ATP) field in the matching NT Mapping table entry is exam-
ined. If the ATP field is set to 0x1, then the AT field is set to ‘translated’ in the TLP emitted by the NT
endpoint in the destination partition. Otherwise, the AT field is set to ‘untranslated’ in the TLP emitted by the
NT endpoint in the destination partition.
Note that completion TLPs always have the AT attribute set to zero and are not subject to address type
field modification.
NT Multicast
The NT function supports non-transparent (NT) multicast, which allows a TLP received by a port in a
switch partition that contains an NT function to be multicasted to other ports of the switch, across partitions.
NT multicast is described in detail in Chapter 17, Multicast.
Inter-Domain Communications
The NT inter-domain communications capability structure provides facilities for supporting communica-
tions between processors in different PCI Express domains.
The NT inter-domain communications capability provides the following facilities:
–
Doorbell registers
–
Message registers
Summary of Contents for PCI Express 89HPES32NT24xG2
Page 20: ...IDT Table of Contents PES32NT24xG2 User Manual x January 30 2013 Notes...
Page 24: ...IDT List of Tables PES32NT24xG2 User Manual xiv January 30 2013 Notes...
Page 28: ...IDT List of Figures PES32NT24xG2 User Manual xviii January 30 2013 Notes...
Page 56: ...IDT PES32NT24xG2 Device Overview PES32NT24xG2 User Manual 1 20 January 30 2013 Notes...
Page 100: ...IDT Switch Core PES32NT24xG2 User Manual 4 22 January 30 2013 Notes...
Page 128: ...IDT Failover PES32NT24xG2 User Manual 6 4 January 30 2013 Notes...
Page 148: ...IDT Link Operation PES32NT24xG2 User Manual 7 20 January 30 2013 Notes...
Page 164: ...IDT SerDes PES32NT24xG2 User Manual 8 16 January 30 2013 Notes...
Page 170: ...IDT Power Management PES32NT24xG2 User Manual 9 6 January 30 2013 Notes...
Page 196: ...IDT Transparent Switch Operation PES32NT24xG2 User Manual 10 26 January 30 2013 Notes...
Page 244: ...IDT SMBus Interfaces PES32NT24xG2 User Manual 12 40 January 30 2013 Notes...
Page 247: ...IDT General Purpose I O PES32NT24xG2 User Manual 13 3 January 30 2013 Notes...
Page 248: ...IDT General Purpose I O PES32NT24xG2 User Manual 13 4 January 30 2013 Notes...
Page 330: ...IDT Switch Events PES32NT24xG2 User Manual 16 6 January 30 2013 Notes...
Page 342: ...IDT Multicast PES32NT24xG2 User Manual 17 12 January 30 2013 Notes...
Page 344: ...IDT Temperature Sensor PES32NT24xG2 User Manual 18 2 January 30 2013 Notes...
Page 384: ...IDT Register Organization PES32NT24xG2 User Manual 19 40 January 30 2013...
Page 492: ...IDT Proprietary Port Specific Registers PES32NT24xG2 User Manual 21 44 January 30 2013 Notes...
Page 588: ...IDT NT Endpoint Registers PES32NT24xG2 User Manual 22 96 January 30 2013 Notes...
Page 710: ...IDT JTAG Boundary Scan PES32NT24xG2 User Manual 25 12 January 30 2013 Notes...
Page 743: ...IDT Usage Models PES32NT24xG2 User Manual 26 33 January 30 2013 Notes...
Page 744: ...IDT Usage Models PES32NT24xG2 User Manual 26 34 January 30 2013 Notes...