Datasheet

Datasheet, Volume 2 207
Processor Configuration Registers
2.11.5 VC0RCTL—VC0 Resource Control Register
This register controls the resources associated with PCI Express* Virtual Channel 0.
B/D/F/Type: 0/6/0/MMR
Address Offset: 114–117h
Reset Value: 800000FFh
Access: RO, RW
Size: 32 bits
BIOS Optimal Default 000h
Bit Access
Reset
Value
RST/
PWR
Description
31 RO 1b Uncore
VC0 Enable (VC0E)
For VC0 this is hardwired to 1 and read only as VC0 can never be
disabled.
30:27 RO 0h Reserved (RSVD)
26:24 RO 000b Uncore
VC0 ID (VC0ID):
Assigns a VC ID to the VC resource. For VC0 this is hardwired to
0 and read only.
23:20 RO 0h Reserved (RSVD)
19:17 RW 000b Uncore
Port Arbitration Select (PAS)
Port Arbitration Select – This field configures the VC resource to
provide a particular Port Arbitration service. This field is valid for
RCRBs, Root Ports that support peer to peer traffic, and Switch
Ports, but not for PCI Express Endpoint devices or Root Ports that
do not support peer to peer traffic.
The permissible value of this field is a number corresponding to
one of the asserted bits in the Port Arbitration Capability field of
the VC resource.
This field does not affect the root port behavior.
16 RO 0h Reserved (RSVD)
15:8 RW 00h Uncore
TC High VC0 Map (TCHVC0M):
Allow usage of high order TCs.
BIOS should keep this field zeroed to allow usage of the reserved
TC[3] for other purposes
7:1 RW 7Fh Uncore
TC/VC0 Map (TCVC0M)
Indicates the TCs (Traffic Classes) that are mapped to the VC
resource. Bit locations within this field correspond to TC values.
For example, when bit 7 is set in this field, TC7 is mapped to this
VC resource. When more than one bit in this field is set, it
indicates that multiple TCs are mapped to the VC resource. In
order to remove one or more TCs from the TC/VC Map of an
enabled VC, software must ensure that no new or outstanding
transactions with the TC labels are targeted at the given Link.
0RO 1bUncore
TC0/VC0 Map (TC0VC0M)
Traffic Class 0 is always routed to VC0.