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

Tom Sylla tsylla at gmail.com
Mon Dec 10 15:36:39 CET 2007

On Dec 9, 2007 4:15 PM, Martin-Éric Racine <q-funk at iki.fi> wrote:
> As far as I can tell, 'flashrom' would need to read some register
> (DIVIL_BALLS - see AMD document 3328G_cs5536_db.pdf page 365) to learn
> what is the primary boot device configured by the bootstrap resistors
> and then try to find the NOR chip used for storing the BIOS there at
> that location.

It is not necessarily *required* for flashrom to do that. The
PRI_BOOT_LOC bits of that MSR say where the transactions go, that is
all. If they are set to 0'b10, transactions above 0xf0000000 go to the
flash controller. When flashrom does the ID sequence, things should
just work.

One complication is that the flash controller has a "write enable" bit
for each of its chip selects. You will find them in the "NOR Flash
Control" MSR. If writes are not enabled, the ID won't even work. (LB
flashrom only comprehends the CPU RCONF write protection disabling,
and does not comprehend the flash controller write enables)

If you are having some sort of specific problem, please give some
detail. My guess is that no ROM is identified on your flash interface
platform, but it does get detected on the LPC platform.

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