Datasheet
Datasheet, Volume 2 53
Processor Integrated I/O (IIO) Configuration Registers
3.2.4.11 BIST—Built-In Self Test Register
3.2.4.12 PBUS—Primary Bus Number Register
3.2.4.13 SECBUS—Secondary Bus Number Register
3.2.4.14 SUBBUS—Subordinate Bus Number Register
BIST
Bus: 0 Device: 0 Function: 0 Offset: 0Fh
Bus: 0 Device: 1 Function: 0–1 Offset: 0Fh
Bus: 0 Device: 2 Function: 0–3 Offset: 0Fh
Bus: 0 Device: 3 Function: 0–3 Offset: 0Fh
Bit Attr
Reset
Value
Description
7:0 RO 0h
BIST Tests
Not supported. Hardwired to 00h.
PBUS
Bus: 0 Device: 1 Function: 0–1 Offset: 18h
Bus: 0 Device: 2 Function: 0–3 Offset: 18h
Bus: 0 Device: 3 Function: 0–3 Offset: 18h
Bit Attr
Reset
Value
Description
7:0 RW 00h
Primary Bus Number
Configuration software programs this field with the number of the bus on the
primary side of the bridge. This register has to be kept consistent with the Internal
Bus Number 0 in the CPUBUSNO01 register. BIOS (and OS if internal bus number
gets moved) must program this register to the correct value since IIO hardware
would depend on this register for inbound configuration cycle decode purposes.
SECBUS
Bus: 0 Device: 1 Function: 0–1 Offset: 19h
Bus: 0 Device: 2 Function: 0–3 Offset: 19h
Bus: 0 Device: 3 Function: 0–3 Offset: 19h
Bit Attr
Reset
Value
Description
7:0 RW 00h
Secondary Bus Number
This field is programmed by configuration software to assign a bus number to the
secondary bus of the virtual PCI-to-PCI bridge. IIO uses this register to either
forward a configuration transaction as a Type 1 or Type 0 to PCI Express.
SUBBUS
Bus: 0 Device: 0 Function: 0 Offset: 1Ah (PCIe MODE)
Bus: 0 Device: 1 Function: 0–1 Offset: 1Ah
Bus: 0 Device: 2 Function: 0–3 Offset: 1Ah
Bus: 0 Device: 3 Function: 0–3 Offset: 1Ah
Bit Attr
Reset
Value
Description
7:0 RW 00h
Subordinate Bus Number
This register is programmed by configuration software with the number of the
highest subordinate bus that is behind the PCI Express port. Any transaction that
falls between the secondary and subordinate bus number (both inclusive) of an
Express port is forwarded to the express port.