Re: boot NetBSD using u-boot

["Doug Fraser" <dwfraser%onebox.com@localhost>]

One note that may help, configure to have an internal
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 r3,
with a length given in r4. If it does not find a valid
symbol table there it crashes....

Using the internal symbols simplifies life.
We use this to load gzipped binaries from FLASH.

Doug

-- 
Douglas Fraser
dwfraser%onebox.com@localhost



-----Original Message-----
From:     Sam Pham <anhmn%yahoo.com@localhost>
Sent:     Tue, 4 Oct 2005 11:09:43 -0700 (PDT)
To:       Doug Fraser 
<dwfraser%onebox.com@localhost>;briggs%netbsd.org@localhost
Cc:       port-powerpc%netbsd.org@localhost
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 tftp.
 However, I'll need to configure the kernel for my
eval board first.  Thanks.

Sam


--- Doug Fraser <dwfraser%onebox.com@localhost> 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 we
> use as the boot
> loader runs in high RAM, and the kernel it loads to
> 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 whole
> thing fits in
> eight Megabytes of FLASH.
> 
> Just a thought....
> 
> -- 
> Douglas Fraser
> dwfraser%onebox.com@localhost
> 
> 
> 
> -----Original Message-----
> From:     Allen Briggs <briggs%netbsd.org@localhost>
> Sent:     Mon, 3 Oct 2005 17:07:27 -0400
> To:       Sam Pham <anhmn%yahoo.com@localhost>
> Cc:       port-powerpc%netbsd.org@localhost
> 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 board,
> > which has u-boot on it.  My understanding is that
> > 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 store
> 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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