Datasheet

Datasheet, Volume 2 89

Processor Integrated I/O (IIO) Configuration Registers

3.3.6.9 DMIVC1RCTL—DMI VC1 Resource Control

Controls the resources associated with PCI Express Virtual Channel 1.

BAR: DMIRCBAR

Offset: 0020h

Bit Attr Default Description

31 RW 0 Virtual Channel 1 Enable (VC1E)

0 = Virtual Channel is disabled.

1 = Virtual Channel is enabled. See exceptions below.

Software must use the VC Negotiation Pending bit to check whether the VC

negotiation is complete. When VC Negotiation Pending bit is cleared, a 1 read

from this VC Enable bit indicates that the VC is enabled (Flow Control

Initialization is completed for the PCI Express port). A 0 read from this bit

indicates that the Virtual Channel is currently disabled.

BIOS Requirement:

1. To enable a Virtual Channel, the VC Enable bits for that Virtual Channel

must be set in both Components on a Link.

2. To disable a Virtual Channel, the VC Enable bits for that Virtual Channel

must be cleared in both Components on a Link.

3. Software must ensure that no traffic is using a Virtual Channel at the

time it is disabled.

4. Software must fully disable a Virtual Channel in both Components on a

Link before re-enabling the Virtual Channel.

30:27 RO 0h Reserved

26:24 RW 001b Virtual Channel 1 ID (VC1ID)

Assigns a VC ID to the VC resource. Assigned value must be non-zero. This

field can not be modified when the VC is already enabled.

23:20 RO 0h Reserved

19:17 RW 0h Port Arbitration Select (PAS)

Configures the VC resource to provide a particular Port Arbitration service.

Valid value for this field is a number corresponding to one of the asserted bits

in the Port Arbitration Capability field of the VC resource.

16:8 RO 0h Reserved

7:1 RW 00h

Traffic Class / Virtual Channel 1 Map (TCVC1M)

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 0

Traffic Class 0/Virtual Channel 0 Map (TC0VC1M)

Traffic Class 0 is always routed to VC0.