[coreboot] Enquries on how to map the bios chip into address space

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Sat Sep 26 19:01:49 CEST 2009

Hi Stanne,

On 25.09.2009 03:20, mtech se13b wrote:
> I'm currently actually trying to access the content of the bios chip while
> the bios is doing its execution. I'm working on Intel Q35 chipset. And i
> understand that while the bios is executing, i can actually access the TOP
> 2MB of the 4 GB address space to access the bios chip  raw data content.
> However, my bios chip is actually 4MB in size, can someone advice how do i
> go about accessing the other 2MB of the bios chip while the bios is
> executing? Because not much documentation on this and i hope someone in the
> coreboot community could help me on this.

It's all documented in the public ICH9 datsheets. If you need example
code, take a look at chipset_enable.c in current flashrom. It can make
sure the top 4 MB are mapped to flash if you specify a special parameter.



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