[Explora-linux-kernel] Explora Pro (PPC403GA)

[Andreas N. <an...@st...>]

hi everybody,

a few weeks ago i managed to get an old explora pro terminal. since then i
tried to get rid of the ncd software and boot linux on it. i'm happy that
i finally found this project and i hope that i can contribute some useful
things in the future.

unfortunately i only own an explora pro with 403 GA ppc chip (which means:
no MMU), so probably the standard kernel won't run on it. i checked some
other embedded linux kernels (like uclinux), but none of them had nommu
support for ppc. however there seems to be generic nommu support in newer
2.5 kernels (mm/nommu.c, activated via CONFIG_MMU)... perhaps i'll get it
to run some day...

but currently there are other problems. i can't even get it to load the
kernel via tftp. i always get an error that the kernel is not valid (and
is not downloaded via tftp). i guess there's some header issue. so
started to try booting your "standalone" program:

the program is loaded via tftp (a progress bar goes up to 100%), then the
terminal displays "used file blablah" and "used host x.x.x.x"... after
that it changes graphic mode from default 640x480@60 to 1280x1024@75. but
after that, some strange things happen. sometimes it outputs lots of
random characters (like doing cat /bin/*), sometimes nothing happens
(blank screen) and sometimes a "8-bit color boot monitor" prompt appears.

i'm not sure what happens, but the program does not run as expected. maybe
this has to do with mmu code in your standalone program? unfortunately i
don't know anything about ppc assembler, so i don't really understand the
start.S code you wrote.

i read that you have problems after activating the mmu. because my explora
doesn't have a mmu i can perhaps skip this step. do you think i would be
able to boot a nommu kernel (if i ever get one compiled)? could you tell
me how to change your standalone program to not do any mmu stuff?

as said i'm not familiar with ppc assembler, but i'm an experienced c/c++
and kernel programmer and i'd be happy to contribute to this project (if i
ever get past the assembler stuff) :)

regards,
andreas neuhaus