[openfirmware] OFW x86 MMU Setup
Andrea
r&d4 at dave-tech.it
Fri Jun 20 17:13:01 CEST 2008
Mitch Bradley wrote:
> Okay, having reread the LPC FLASH chip manual, I see what is happening.
> (My intuition about LPC FLASH devices is deficient because I took a
> break from doing firmware during the period when Intel was inventing FWH.)
>
> The virtual address range that OFW uses - see pc/virtaddr.fth :
> fw-virt-base , fw-virt-size - overlaps the physical address range that
> LPC FLASH chips use. I probably would not have picked that virtual
> range had I realized that LPC devices decode more address space than
> they use for the data array.
>
> Address conflicts like this is one of the reasons why virtual=physical
> address assignment is problematic.
> [snip]
Thanks for the clear explanation Mitch.
I tried to use dynamic virtual address allocation but I have the same
problem, which (IMHO) is a confirmation that the trick is at lower lever
than virtual addressing.
Thanks anyway & best regards,
--
Andrea
DAVE Srl - Electronics System House
e-mail address: r&d4 at dave-tech.it
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