Re: boot NetBSD using u-boot

[Allen Briggs <briggs%netbsd.org@localhost>]

On Wed, Oct 05, 2005 at 02:10:59PM -0700, Sam Pham wrote:
> Thank you for your tip.  Since I'm a newbie to both
> u-boot and NetBSD, could someone point me to some
> pointers/documentation/books that explain how to boot
> NetBSD in powerpc embedded environment and/or what
> NetBSD expects from the bootloader?  In particular,
> the handoff process between a bootloader such as
> u-boot and NetBSD would help a lot.

If you use tftpboot, U-Boot will download data to the specified
address (specified in the tftpboot commandline or in the "loadaddr"
environment variable).  You can just 'go addr' to jump to an address
(presumably the entry point in the binary image you just loaded).
You can also use "bootm" which expects a specific "image header"
(defined in U-Boot) to be at the 'loadaddr' location.  If you
use bootm and that image header specifies a NetBSD image, it will
pass a few bits of information to you in r3, r4, r5, and r6.  The
startup code for your kernel can chose to use or ignore that info.
There's not much else going on between the two.

The "bootm" actions are in u-boot*/common/cmd_bootm.c.

-allen

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