[LinuxBIOS] LinuxBIOS 'flashrom' on Geode LX + CS5536

Martin-Éric Racine q-funk at iki.fi
Tue Dec 11 23:42:44 CET 2007

On 12/11/07, ron minnich <rminnich at gmail.com> wrote:
> I use a script to set DIVIL_BALLS  FWIW.
> but auto sensing? Never worked for me. Is it really possible?

Dave Frodin of AMD replied on the Geode mailing list (talking about
how their non-free gx_util.c and closed-source AMD flashrom work):

> In regards to gx_util usage, /dev/mem will not work for accesses to the very top of
> memory. I believe it will not allow access to the top 64k bytes of memory. Which is
> fine unless you want to modify the system BIOS.
> In regards to the DIVIL_BALL settings.  FlashROM checks to see what device was
> booted from (i.e. LPC, flash controller) before the flash device is identified. If the
> boot device is the flash controller, FlashROM has to flip the IDE/flash switch before
> any accesses to the flash device since the IDE interface is most likely where
> FlashROM and any BIOS images exist.

Which, if I'm not mistaken, is actually the opposite, since IDE and
NAND controllers are mutually exclusive, while NOR flash used for
system BIOS sits somewhere else?

Anyhow, beyond scanning DIVIL_BALLS, it appears that if something
*other* than the LPC hub is found as the primary device, a bit must be
switched to actually be able to access the chip.

Martin-Éric Racine

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