bootloader for deeply embedded 405CR

bootloader for deeply embedded 405CR

[Bryan Rittmeyer]

Hello linuxppc-embedded,

I am attempting to boot Montavista's PPC405 Linux port on
a very minimal 405CR Rev C target: essentially, there's 64MB
of SDRAM and a minicom on UART0. I have a 405GP kernel
loading great on the Walnut board using the IBM serial
monitor and treeboot, but I'm unsure what I need to do
on the CR before I can begin successfully running Linux on it.
I am using an Abatron BDI2000 along with GDB to load code and
tweak registers on the target.

Right now, I am configuring the SDRAM controller and UART0,
but apparently that is not sufficient to fully boot Linux,
since I never get any output on the serial port except for
the 'a' debug printout I enabled in head_4xx.S

Does anyone have a minimal 405GP/CR bootloader that I
could use as an example? Or perhaps a FAQ on how to bring
up a deeply embedded 405 using the Abatron box?

Thanks,

Bryan Rittmeyer

--
Bryan Rittmeyer
mailto:bryan@ixiacom.com
Ixia Communications
26601 W. Agoura Rd.
Calabasas, CA 91302

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Re: bootloader for deeply embedded 405CR

[Wolfgang Denk]

Dear Bryan,

in message <3ACF73E8.24CAACE4@ixiacom.com> you wrote:
>
> Does anyone have a minimal 405GP/CR bootloader that I
> could use as an example? Or perhaps a FAQ on how to bring
> up a deeply embedded 405 using the Abatron box?

Did you try to run our Open Source Firmware "PPCBoot" on your  board?
The Walnut is one of the many supported configurations.

See the project page at ppcboot.sourceforge.net, which points you  to
the CVS server on sourceforge or our FTP server at
ftp://ftp.denx.de/pub/ppcboot/

For PPCBoot related  questions  you  can  subscribe  to  the  PPCBoot
mailing list (ppcboot-users@lists.sourceforge.net).

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Contrary to popular belief, thinking does not cause brain damage.

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AW: bootloader for deeply embedded 405CR

[Stefan Roese]

> > Does anyone have a minimal 405GP/CR bootloader that I
> > could use as an example? Or perhaps a FAQ on how to bring
> > up a deeply embedded 405 using the Abatron box?
>
> Did you try to run our Open Source Firmware "PPCBoot" on your  board?
> The Walnut is one of the many supported configurations.

Yes, you should give PPCBoot a try. There is also a PPC405CR implementation
available - "canbt". This board is running PPCBoot as a boot loader firmware
and Linux as OS.

Stefan Roese

*******************************************
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Vahrenwalder Str. 205
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Phone: +49-511-37298-0
Fax:   +49-511-37298-198
email: stefan.roese@esd-electronics.com
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Re: bootloader for deeply embedded 405CR

[Bryan Rittmeyer]

Wolfgang Denk wrote:

> For the Walnut it should be a simple thing to do:
>
>         make WALNUT405_config
>         make

Hello Wolfgang,

I have built a CVS ppcboot as you suggest, however
it appears to expect being burned into flash
memory.

What I would like to do is GDB-load an ELF ppcboot
into the Walnut's 32MB SDRAM mapped at address 0,
then execute it in place. Then I want to GDB load a
kernel at another higher address, and use ppcboot
to boot it. Is this already possible or will I have
to modify Makefiles, linker scripts, and possibly
code?

Regards,

Bryan

--
Bryan Rittmeyer
mailto:bryan@ixiacom.com
Ixia Communications
26601 W. Agoura Rd.
Calabasas, CA 91302

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Re: bootloader for deeply embedded 405CR

[Wolfgang Denk]

*** Please send PPCBoot related messages to the PPCBoot mailing list ***




In message <3AD370AA.93F59622@ixiacom.com> you wrote:
>
> > For the Walnut it should be a simple thing to do:
> >         make WALNUT405_config
> >         make
>
> I have built a CVS ppcboot as you suggest, however
> it appears to expect being burned into flash
> memory.

Right. That's what most of the people do.

> What I would like to do is GDB-load an ELF ppcboot
> into the Walnut's 32MB SDRAM mapped at address 0,
> then execute it in place. Then I want to GDB load a
> kernel at another higher address, and use ppcboot
> to boot it. Is this already possible or will I have
> to modify Makefiles, linker scripts, and possibly
> code?

You have to modify the link address at least; but most  probably  you
have  to  modify  other  code  as  well - for instance to prevent the
exception handlers to be installed, etc.

Why don't you do what everybody does, and write the image to flash?

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
"Here's a fish hangs in the net like a poor man's right in  the  law.
'Twill hardly come out."     - Shakespeare, Pericles, Act II, Scene 1

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