Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
5.2.21.1.1 Using PCC registers
OSPM will write PCC registers by filling in the register value in PCC sub channel space and issuing
a PCC Execute command. See Table 5-89, below. All other command values are reserved.
Table 5-89 PCC Command Codes used by MPST Platform Communication Channel
Command Description
0x00-0x02
All other values are reserved.
0x03
Execute MPST Command.
0x04-0xFF
All other values are reserved.
Table 5-90 MPST Platform Communication Channel Shared Memory Region
Field
Byte
Length
Byte
Offset
Description
Signature 4 0 The PCC signature. The signature of a subspace is computed by
a bitwise-or of the value 0x50434300 with the subspace ID. For
example, subspace 3 has signature 0x50434303.
Command 2 4 PCC command field, seeSection 14 and Table 5-89.
Status 2 6 PCC status field, see Section 14
Communication Space
MEMORY_POWER
_COMMAND_REGI
STER
4 8 Memory region for OSPM to write the requested memory power
state.
Write:
1 to this field to GET the memory power state
2 to this field to set the memory power state
3 – GET AVERAGE POWER CONSUMED
4 – GET MEMORY ENERGY CONSUMED
174 April, 2015 Version 6.0