Datasheet

Processor Uncore Configuration Registers
348 Datasheet, Volume 2
28 ROS-V 0h
SMB_BUSY: SMBus Busy state
This bit is set by iMC while an SMBus/I
2
C command (including TSOD command
issued from IMC hardware) is executing. Any transaction that is completed
normally or gracefully will clear this bit automatically. By setting the
SMB_SOFT_RST will also clear this bit.
This register bit is sticky across reset; thus, any surprise reset during pending
SMBus operation will sustain the bit assertion across surprised warm-reset. The
BIOS reset handler can read this bit before issuing any SMBus transaction to
determine whether a slave device may need special care to force the slave to idle
state (such as, using clock override toggling (SMB_CKOVRD) and/or using induced
time-out by asserting SMB_CKOVRD for 25-35 ms).
27 RV 0h Reserved
26:24 RO-V 111b
Last Issued TSOD Slave Address
This field captures the last issued TSOD slave address. Following is the slave
address and the DDR CHN and DIMM slot mapping:
Slave Address: 0 -- Channel: Even Chn; Slot #: 0
Slave Address: 1 -- Channel: Even Chn; Slot #: 1
Slave Address: 2 -- Channel: Even Chn; Slot #: 2
Slave Address: 3 -- Channel: Even Chn; Slot #: 3 (reserved for future use)
Slave Address: 4 -- Channel: Odd Chn; Slot #: 0
Slave Address: 5 -- Channel: Odd Chn; Slot #: 1
Slave Address: 6 -- Channel: Odd Chn; Slot #: 2
Slave Address: 7 -- Channel: Odd Chn; Slot #: 3 (reserved for future use)
Since this field only captures the TSOD polling slave address, during SMB error
handling, software should check the hung SMB_TSOD_POLL_EN state before
disabling the SMB_TSOD_POLL_EN in order to qualify whether this field is valid.
23:16 RV 0h Reserved
15:0 RO-V 0000h
SMB_RDATA
Read DataHolds data read from SMBus Read commands.
Since TSOD/EEPROM are I
2
C devices and the byte order is MSByte first in a word
read, reading of I
2
C using word read should return SMB_RDATA[15:8]=I2C_MSB
and SMB_RDATA[7:0]=I2C_LSB. If the reading of I
2
C using byte read, the
SMB_RDATA[15:8]=donít care; SMB_RDATA[7:0]=read_byte.
If we have a SMB slave connected on the bus, reading of the SMBus slave using
word read should return SMB_RDATA[15:8]=SMB_LSB and
SMB_RDATA[7:0]=SMB_MSB.
If the software is not sure whether the target is I
2
C or SMBus slave, use byte
access.
SMB_STAT_[0:1]
Bus: 1 Device: 15 Function: 0 Offset: 180h
Bit Attr
Reset
Value
Description