IDT Non-Transparent Mode Operation
PES16NT2 User Manual
10 - 5
April 15, 2008
Notes
Figure 10.3 NTB Base and Limit Address Translation
A base and limit address translation mechanism is employed to translate the address of transactions
that flow through the NTB. This is graphically illustrated in Figure 10.3. The translated address corresponds
to the offset address bits of the matching BAR added to the value in the translated base address (BART-
BASEx) register. If this value is less than or equal that stored in the corresponding translated limit address
(BARTLIMITx) register, then the transaction, with the new translated address, is forwarded to the opposite
side of the NTB. If the value is greater than the value in the BARTLIMITx register, then the transaction is
treated in the same manner as a transaction that does not match any of the BARs.
The translated base address consists of the TBADDR field shifted left four bit positions (i.e., corre-
sponding bit positions of this field and the offset address bits of the BAR are added). In the same manner,
the translated limit address consists of the TLADDR field shifted left four bit positions. The bus number in
the requester ID in the forwarded transaction is equal to the bus number of the NTB endpoint on the oppo-
site side of the non-transparent bridge. The device and function number of the requester ID in the
forwarded transaction is equal to the matching mapping entry table address. For example if the matching
mapping table entry was 14, then the device number would be one and function number would be six.
If a posted address routed transaction is received that matches a BAR but whose requester ID is not in
the mapping table, then the Forward Mapping Table Miss (FMTMISS) bit is set in the NTBSTS register of
the NTB endpoint on which the transaction was received and the transaction is treated as an unsupported
request. An address routed transaction received by the internal endpoint that maps to the external domain
when the Port C link is down is treated as a mapping table miss. When this occurs, the Forward Mapping
Table Miss (FMTMISS) bit is set in the internal NTB endpoint NTBSTS register and the transaction is
treated as an unsupported request.
If an address routed transaction is received that does not match any of the BARs, the BAR Miss
(BARMISS) bit is set in the NTBSTS register and the transaction is treated as an unsupported request. If
I/O transactions are not enabled via the IOAE bit in the PCICMD register and an I/O request is received, the
transaction is treated as an unsupported request. If memory transactions are not enabled via the MAE bit in
the PCICMD register and a memory request is received, then the transaction is treated as an unsupported
request. If the BME bit is cleared in the PC_PCICMD register or the PCIE_PCICMD register and a memory
or I/O request is received on the external side of the NTB, then the transaction is treated as an unsupported
request. If the corresponding case occurs on the external side of the NTB, then it is also treated as an
unsupported request.
Transaction Address
Base Address
Offset Address
BAR
Translated Base Address
BARTBASEx
+
Translated Limit Address
BARTLIMITx
>
*
No
*
(Offset A BARTBASEx) > BARTLIMITx
Translated
Transaction Address
Yes
Unsupported
Request
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 44: ...IDT Clocking Reset and Initialization Clock Operation PES16NT2 User Manual 2 12 April 15 2008 Notes...
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Страница 78: ...IDT SMBus Interfaces PES16NT2 User Manual 6 16 April 15 2008 Notes...
Страница 83: ...IDT NTB Upstream Port Failover PES16NT2 User Manual 7 5 April 15 2008 Notes...
Страница 84: ...IDT NTB Upstream Port Failover PES16NT2 User Manual 7 6 April 15 2008 Notes...
Страница 130: ...IDT Transparent Mode Operation PES16NT2 User Manual 9 44 April 15 2008 Notes...
Страница 284: ...IDT Non Transparent Mode Operation PES16NT2 User Manual 10 154 April 15 2008 Notes...