[jornada] Jornada 820

Dear Jornada users,

for weeks, I haven't done much with porting Linux to the 820;
I was just using it with Emacs on WinCE.
But today, I went to channel #kernelnewbies and found help from Erik Mouw.

Erik advised me to try to port blob, a boot loader,
so as to have a small working tool from which to boot linux.
Indeed, hpcboot from NetBSD can do many things,
but it can only load an ELF binary, and
it cannot pass configuration information to the Linux kernel,
whereas the kernel needs this information,
and needs some initialization code done in the zImage uncompressor,
whereas only vmlinux.gz and not zImage is recognized by hpcboot.

So I "ported" blob to the jornada820.
Everything went rather fine, and in the end,
blob was outputting is welcome message on the serial line,
but was crashing before the first line went through.
After blob is booted, the whole LCD goes black,
but I can't say whether that happens before or after the crash.
Accelerating blob's serial speed would allow it to print more
before it crashed, so that looks like an interrupt is received
and mishandled. I tried to hack around to determine whether
hpcboot did manage to get us in SVC mode, but all I managed to do
was to crash blob sooner, and now, I can't even restore its semi-working
state, even though the diff set is rather small and I can't imagine
what I modified and didn't #ifdef away in the blob sources.

As usual, my pathetic attempts are fully documented and available on
        ftp://Samaris.tunes.org/jornada820/
        ftp://Samaris.tunes.org/jornada820/linux/README.blob

Note that hpcboot reports CPSR :600000df which is suspect at best.
Erik thinks hpcboot fails to enter SVC mode.

All in all, I'm rather baffled.
Being able to have any output would help.
Does anyone know how to program e.g. the backlight of the LCD?
Does anyone know how to enter SVC mode from WinCE 2.11?
How to check we're there?
Is anyone else working on porting linux to the jornada 820?
Can anyone else give me good advice on this porting issue?
Does anyone else have information about the hardware configuration
of the machine? (what devices mapped where, to be used with what parameters)

Hum. Time to sleep.

[ François-René ÐVB Rideau | Reflection&Cybernethics | http://fare.tunes.org ]
[ TUNES project for a Free Reflective Computing System | http://tunes.org ]
Lie, n.:
        A very poor substitute for the truth, but the only one
discovered to date.
Received on Thu May 30 2002 - 23:56:00 EDT