[ECOS] redboot on i386 serial ports

Mark Grosberg mark@nolab.conman.org
Wed Aug 6 06:38:00 GMT 2003



> Thanks for the help, however, after rebuilding with
> the enet disabled, I still only get a bunch of dots
> (well, exactly 80 dots). Are they coming from redboot?

FWIW, the dots are printed in the real-mode floppy loader code, which is
in:

  packages/hal/i386/pcmb/v2_0/include/pcmb.inc

here:

  movw    $(0x0E*256+'.'), %ax    /* print a dot */
  int     $0x10

The dots indicate that the real mode startup code is loading the image
into RAM. After the dots then eCos tries to do PC-like things (disable
A20, etc) and then go into protected mode.

Here is another thing: Have you tried using GRUB to load your image
(without HAL_STARTUP_TYPE == FLOPPY)?

> Where do I start troubleshooting? This is "suppose"
> to be a standard 386 PC, but I'm starting to doubt
> since it obviously has no floppy controller. they are
> playing some tricks somewhere to get the flash to look
> like a floppy. Its General Software embedded BIOS.

Well, the .'s are a good thing then. It means the "fake floppy" is being
understood by eCos. eCos' loader just calls the BIOS, so the fakeout
should work.

There is something else wrong. I suppose the obvious thing is a litmus
test of your environment. Try and get an ordinary PC and boot it up. If
that works, you can rule out a lot of common stuff.

Do you have a checkpoint card? Can you insert checkpoints into the eCos
startup and see how far you get?

> So, where do I start? What kind of hardware does
> redboot assume is there in the 386 config?

What about keyboard? PS/2 right? (USB would be bad).

I've seen some 8042's in the wild that didn't respond properly to commands
to turn off the A20 gate in some chipsets. It required some BSP hacking to
get VxWorks to run.

What other operating systems (besides DOS) can this hardware run? Linux?
BSD? NT?

Hope this gives you a starting point.



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