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Core Logic Module
Power Management SMI Status Reporting Registers
The Core Logic module updates status registers to reflect
the SMI sources. Power management SMI sources are the
device idle timers, address traps, and general purpose I/O
pins.
Power management events are reported to the GX1 mod-
ule through the active low SMI# signal. When an SMI is ini-
tiated, the SMI# signal is asserted low and is held low until
all SMI sources are cleared. At that time, SMI# is de-
asserted.
All SMI sources report to the Top Level SMI Status register
(F1BAR0+I/O Offset 02h) and the Top Level SMI Status
Mirror register (F1BAR0+I/O Offset 00h). The Top SMI Sta-
tus and Status Mirror registers are the top level of hierarchy
for the SMI Handler in determining the source of an SMI.
SMI# Asserted
GX1
Module
Core Logic
Module
F1BAR0+I/O
Offset 02h
Read to Clear
to determine
top-level source
of SMI
Bits [15:10]
Other_SMI
Bit 9
GTMR_TRP_SMI
Bits [8:0]
Other_SMI
Top Level
Figure 6-11. General Purpose Timer and UDEF Trap SMI Tree Example
AMD Geode™ SC3200 Processor Data Book
SMM software reads SMI Header
If Bit X = 1
(External SMI)
SMI De-asserted after all SMI Sources are Cleared
(i.e., Top and Second Levels - note some sources may have a Third Level)
If bit 9 = 1,
Source of SMI
is GP Timer or UDEF Trap
These two registers are identical except that reading the
register at F1BAR0+I/O Offset 02h clears the status.
Since all SMI sources report to the Top Level SMI Status
register, many of its bits combine a large number of events
requiring a second level of SMI status reporting. The sec-
ond level of SMI status reporting is set up very much like
the top level. There are two status reporting registers, one
"read only" (mirror) and one "read to clear". The data
returned by reading either offset is the same, the difference
between the two being that the SMI can not be cleared by
reading the mirror register.
Figure 6-11 on page 163 shows an example SMI tree for
checking and clearing the source of General Purpose Tim-
ers and the User Defined Trap generated SMI.
If Bit X = 0
(Internal SMI)
Call internal SMI handler
to take appropriate action
F1BAR0+I/O
Offset 06h
Read to Clear
to determine
second-level
source of SMI
Bits [15:6]
RSVD
Bit 5
PCI_TRP_SMI
Bit 4
UDEF3_TRP_SMI
Bit 3
UDEF2_TRP_SMI
Bit 2
UDEF1_TRP_SMI
Bit 1
GPT2_SMI
Bit 0
GPT1_SMI
Second Level
32581C
Take
Appropriate
Action
163
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