Datasheet
Datasheet, Volume 2 107
Processor Integrated I/O (IIO) Configuration Registers
3.2.4.87 PCIE_IOU_BIF_CTRL—PCIe* Port Bifurcation Control
Register – DMI2 Port/PCIe*
3.2.4.88 DMICTRL—DMI Control Register
PCIE_IOU_BIF_CTRL
Bus: 0 Device: 0 Function: 0 Offset: 190h
Bit Attr
Reset
Value
Description
15:4 RV 0h Reserved
3WO 0b
IOU Start Bifurcation
When software writes a 1 to this bit, IIO starts the port 0 bifurcation process.
After writing to this bit, software can poll the Data Link Layer link active bit in the
LNKSTS register to determine if a port is up and running. Once a port bifurcation
has been initiated by writing a 1 to this bit, software cannot initiate any more
write-1 to this bit (write of 0 is ok).
Note: This bit can be written to a 1 in the same write that changes values for bits
2:0 in this register and in that case, the new value from the write to bits 2:0 take
effect.
This bit always reads a 0b.
2:0 RO 000b
IOU Bifurcation Control
To select a IOU bifurcation, software sets this field and then either
1. sets bit 3 in this register to initiate training OR
2. resets the entire processor and on exit from that reset,
The processor will bifurcate the ports per the setting in this field. In Port 0, it is
hardwired to never bifurcate.
000 = x4
others = Reserved
DMICTR
Bus: N Device: 0 Function: 0 CFG Mode: Parent
Offset: 1A0
Bit Attr
Reset
Value
Description
63:2 RO
000000
000000
0000h
Reserved
1RW1b
Auto Complete PM Message Handshake
This bit, if set, enables the DMI port to automatically complete PM message
handshakes by generating an Ack_Sx or Rst_Warn_Ack message down DMI for
the following DMI messages received:
Go_S0
Go_S1_RW
Go_S1_Temp
Go_S1_Final
Go_S3
Go_S4
Go_S5
Rst_Warn
0RW1b
Abort Inbound Requests
Setting this bit causes IIO to abort all inbound requests on the DMI port. This will
be used during specific power state and reset transitions to prevent requests from
PCH. This bit does not apply in PCI Express mode.
Inbound posted requests will be dropped and inbound non-posted requests will be
completed with Unsupported Request completion. Completions flowing inbound
(from outbound requests) will not be dropped, but will be forwarded normally.
This bit will not affect S-state auto-completion, if it is enabled.