307013-003 Datasheet, PDF (142/848 Pages) Intel Corporation – Intel I/O Controller Hub 7

Functional Description
5.10.4.1
Edge-Triggered Operation
In this case, the “Assert Message” is sent when there is an inactive-to-active edge on
the interrupt.
5.10.4.2
Level-Triggered Operation
In this case, the “Assert Message” is sent when there is an inactive-to-active edge on
the interrupt. If after the EOI the interrupt is still active, then another “Assert Message”
is sent to indicate that the interrupt is still active.
5.10.4.3
Registers Associated with Front Side Bus Interrupt Delivery
Capabilities Indication: The capability to support Front Side Bus interrupt delivery is
indicated via ACPI configuration techniques. This involves the BIOS creating a data
structure that gets reported to the ACPI configuration software.
5.10.4.4 Interrupt Message Format
The ICH7 writes the message to PCI (and to the Host controller) as a 32-bit memory
write cycle. It uses the formats shown in Table 5-17 and Table 5-18 for the address and
data.
The local APIC (in the processor) has a delivery mode option to interpret Front Side Bus
messages as a SMI in which case the processor treats the incoming interrupt as a SMI
instead of as an interrupt. This does not mean that the ICH7 has any way to have a SMI
source from ICH7 power management logic cause the I/O APIC to send an SMI
message (there is no way to do this). The ICH7’s I/O APIC can only send interrupts due
to interrupts which do not include SMI, NMI or INIT. This means that in IA32/IA64
based platforms, Front Side Bus interrupt message format delivery modes 010
(SMI/PMI), 100 (NMI), and 101 (INIT) as indicated in this section, must not be used
and is not supported. Only the hardware pin connection is supported by ICH7.
:
Table 5-17. Interrupt Message Address Format
Bit
31:20
19:12
11:4
3
2
1:0
Description
Will allways be FEEh
Destination ID: This is the same as bits 63:56 of the I/O Redirection Table entry for
the interrupt associated with this message.
Extended Destination ID: This is the same as bits 55:48 of the I/O Redirection
Table entry for the interrupt associated with this message.
Redirection Hint: This bit is used by the processor host bridge to allow the interrupt
message to be redirected.
0 = The message will be delivered to the agent (processor) listed in bits 19:12.
1 = The message will be delivered to an agent with a lower interrupt priority This can
be derived from bits 10:8 in the Data Field (see below).
The Redirection Hint bit will be a 1 if bits 10:8 in the delivery mode field associated
with corresponding interrupt are encoded as 001 (Lowest Priority). Otherwise, the
Redirection Hint bit will be 0
Destination Mode: This bit is used only the Redirection Hint bit is set to 1. If the
Redirection Hint bit and the Destination Mode bit are both set to 1, then the logical
destination mode is used, and the redirection is limited only to those processors that
are part of the logical group as based on the logical ID.
Will always be 00.
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Intel ^® ICH7 Family Datasheet