[coreboot] question about mapping of registers to I/O locations

Ed Swierk eswierk at aristanetworks.com
Tue Nov 4 22:47:25 CET 2008

On Tue, Nov 4, 2008 at 1:37 PM, Shadravan Fontanov
<shadravan.fontanov at googlemail.com> wrote:
> citation from  datasheet of ICH5/ICH5R chipset
> (http://download.intel.com/design/chipsets/datashts/25251601.pdf),
> page 385:
> "These registers are enabled in the PCI Device 31: Function 0 space
> (PM_IO_EN), and can be
> moved to any I/O location (128-byte aligned)."
> I didnt understand, who moves the registers in the i/o space -- BIOS,
> or linux kernel? Is there a default value for PMBASE (0x800), at which
> the registers are visible after starting the machine, without the need
> of explicit i/o mapping?

See the definition of PMBASE on page 322.


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