Datasheet

System Address Map
4-4 Intel
®
E8870 Scalable Node Controller (SNC) Datasheet
Some FWH components implement more than 4 MB of firmware space. These components
support internal paging registers to allow software to map the SNC 4MB window into the larger
component. In other words, software will first program the paging register to move the base
address and subsequent accesses to the firmware will be offset by that amount.
Only single-byte writes are supported to this range. These writes are interpreted as commands by
the Flash device. Locked accesses to this range are not supported.
Figure 4-2 depicts the E8870 chipset firmware map using 82802 firmware hub devices as an
example for Local Firmware Range enabled. Figure 4-3 depicts the E8870 chipset firmware map
using 82802 Flash devices as an example for Local Firmware Range disabled.
4.1.2.2 Global Firmware Range
The Global Firmware Range (12 MB) lies from FF00_0000h to FFBF_FFFFh if Local Firmware
Range is enabled (see Figure 4-2). If Local Firmware is disabled (see Figure 4-3), Global Firmware
range includes the FFC0_0000 to FFFF_FFFFh address range. Requests in this range are directed
to the compatibility bus. The ICH4 will route these to its FWH interface. This range is accessible
from any processor bus and can be written inbound.
4.1.2.3 Processor Specific Region
This 4-MB range is used for processor-specific applications. It lies between FEC0_0000h and
FEFF_FFFFh, and is split into four 1MB segments.
Interrupt Range
Requests to the address range FEE0_0000h to FEEF_FFFFh are used to deliver interrupts. Memory
reads or write transactions to this range are illegal from the processor. The processor issues
interrupt transactions to this range. Inbound interrupts in the form of memory writes to this range
are converted by the SIOH to non-coherent memory writes in SP, with Attr = INT.
Reserved Ranges
The E8870 chipset will master abort requests to the FEF0_0000h - FEFF_FFFFh or FED0_0000h -
FEDF_FFFFh ranges.
I/O APIC Controller and Hot-Plug Controller Range (SAR)
This address range FEC0_0000h to FECF_FFFFh is used to program the IOAPIC controller in the
P64H2 and for targeted EOI writes. The FECx_xxxxh area is also used for the Hot Plug controller
in the P64H2. The attribute field in request packets to this range is set to MMIO.
In a multi-node environment, this region can be partitioned into two contiguous sub-ranges, one for
each SIOH. The SIOH with the compatibility bus must be assigned the lowest sub-range, since the
Interrupt Re-direction Register in the ICH4 is hard-coded to the FEC0_0000h address. These sub-
ranges may be divided into nine sub-ranges, which may be allotted to the different PCI buses
connected to the hublinks.
The SIOH supports a relocatable IOAPIC register range, but the SNC does not.