Re: [Qemu-devel] [5765] uImage: only try to load 'kernel' images (Hollis Blanchard)

[Hollis Blanchard <hollisb@us.ibm.com>]

On Thu, 2008-11-20 at 23:29 +0100, François Revol wrote:
> > IH_TYPE_STANDALONE images could be loaded, but would unexpectedly 
> > fail if they
> > tried to use any uboot services.
> 
> Hmm how is it planned to support the external API that is being 
> developped ?
> It's being added for NetBSD IIRC, and I'll probably need that for Haiku 
> as well, or use the boot loader as a standalone image.

I don't know anything about it, but assuming you mean a runtime API
u-boot offers to applications it's loaded, I don't see that qemu needs
to be involved at all.

> We would still have an u-boot rom around anyway, wouldn't we?

It's possible to implement the API in qemu itself (using a magic
"call-out" instruction), but running u-boot itself inside the VM is the
best option. (At one point Jocelyn claimed that this already works with
qemu's 405 emulation, but I could never get it to work.)

The code that I've posted is specifically to load uImages, so it
wouldn't be used to load u-boot itself. In the Bamboo patches I'm
working on, I just replicate the post-load environment u-boot leaves
behind (register state, device tree, kernel load address, TLB entries,
etc). This bypasses the need for a u-boot ROM.

-- 
Hollis Blanchard
IBM Linux Technology Center