Subject: Re: boot NetBSD using u-boot
To: None <email@example.com>
From: Sam Pham <firstname.lastname@example.org>
Date: 10/05/2005 14:10:59
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.
I really appreciate any help.
--- Doug Fraser <email@example.com> wrote:
> One note that may help, configure to have an
> symbol table. For the powerpc port, if you set
> r3 and r4 to zero on boot, it will use the internal
> symbol table, so you can load and boot a pure binary
> instead of loading using an ELF loader.
> If you set r3 and r4 to anything other than zero, it
> goes looking for a symbol table at the address in
> with a length given in r4. If it does not find a
> symbol table there it crashes....
> Using the internal symbols simplifies life.
> We use this to load gzipped binaries from FLASH.
> Douglas Fraser
> -----Original Message-----
> From: Sam Pham <firstname.lastname@example.org>
> Sent: Tue, 4 Oct 2005 11:09:43 -0700 (PDT)
> To: Doug Fraser
> Cc: email@example.com
> Subject: RE: Re: boot NetBSD using u-boot
> Thank you for your responses. uboot documentation
> misled me to think that stage 2 loader is needed to
> boot NetBSD. I'll try to boot it directly using
> However, I'll need to configure the kernel for my
> eval board first. Thanks.
> --- Doug Fraser <firstname.lastname@example.org> wrote:
> > We are using a very simple initializer for the
> > Marvell bridge then
> > bootstrapping NetBSD from FLASH. That minimally
> > configured kernel
> > just knows about the disk drive, and mounts it,
> > loads the real run time
> > kernel and that is the end.
> > So, the initializer lives in low RAM. The kernel
> > use as the boot
> > loader runs in high RAM, and the kernel it loads
> > disk lives in low
> > RAM. It works quite well. We also keep a rescue
> > kernel in FLASH
> > so that if we have disk problems, we can boot the
> > rescue kernel and
> > do disk and network operations from there. The
> > thing fits in
> > eight Megabytes of FLASH.
> > Just a thought....
> > --
> > Douglas Fraser
> > email@example.com
> > -----Original Message-----
> > From: Allen Briggs <firstname.lastname@example.org>
> > Sent: Mon, 3 Oct 2005 17:07:27 -0400
> > To: Sam Pham <email@example.com>
> > Cc: firstname.lastname@example.org
> > Subject: Re: boot NetBSD using u-boot
> > On Mon, Oct 03, 2005 at 01:48:50PM -0700, Sam Pham
> > wrote:
> > > I'd like to port NetBSD on the mpc8540eval
> > > which has u-boot on it. My understanding is
> > > u-boot needs the stage 2 NetBSD loader to boot
> > NetBSD.
> > That seems to be what it wants, but you can also
> > just download
> > kernel code and jump to it ('tftp' and 'go').
> > The stage 2 loader usually lives in
> > arch/<plat>/stand/...
> > and is different for each system because it's kind
> > of a
> > bridge between the kernel and the host system. It
> > might
> > have knowledge of devices and filesystem formats
> > that the
> > host system's ROM (u-boot, in your case) doesn't.
> > It's not clear to me why the 'stage 2 loader' that
> > uboot
> > expects couldn't be a kernel for development. A
> > stage 2
> > loader would be really nice for being able to
> > the
> > kernel on, say, a SATA controller on PCI or some
> > such,
> > but for development, you're probably just
> > downloading
> > with an ICE or via tftp.
> > -allen
> > --
> > Use NetBSD!
> > http://www.NetBSD.org/
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