[U-Boot-Users] Problems with u-boot, PPChameleonEVB and MontaVista kernel

[Andy Hawkins]

> Is there any special reason to use their kernel? What does it
contain
> that you cannot find in DAVE's / our tested and working kernel tree?

Well, we've decided to use the MontaVista distribution / development
environment, and that integrates nicely with their kernel build tools.
There may well be features that are present in the MontaVista kernel
tree that we would like to use too (although I'd have to check the
details). I think the general feeling is that having one source for
all this is the best way to go (if we can get it to work).

> You have to accept the fact that "similar" is not  good  enough.
You
> must  use  a  kernel  which  has  been proted to the _exact_
matching
> board, or you will run into problems sooner or later -  at  least
if
> you  don't  understand EXACTLY what you are doing (which seems not
to
> be the case - no offence meant).

You're absolutely right, I don't understand exactly what I'm doing :).
No offence taken whatsoever. I've read through most of 'Understanding
the Linux Kernel', but unfortunately it only covers the early kernel
boot process for the i386 architecture. Is there any other reference
that can give more information for the PowerPC?

> Of course. You shall break compatibility to the  rest  of  the
world
> just to make their kernel work. What a nonsense.
>
> > I do have access to a BDI2000, that I've used to break into
> a running
> > kernel (at start_here), but can't get it to break when I use the
> > MontaVista kernel. From this, I assume that it's failing somewhere
> > very early in the linux boot process.
> >
> > Can anyone offer any advice?
>
> Your question is a FAQ:
>
http://www.denx.de/twiki/bin/view/DULG/LinuxHangsAfterUncompressingKer
nel

I've followed the information in that FAQ. However, all it tells me to
do is match up the bd_info structures, and check clock information.

> What I cannot understand is why you are wasting your time (and
ours) if you
> have a working kernel which you can use.

It just seems to make sense to try to keep everything (kernel, apps,
development etc.) under 'one roof' (i.e. MontaVista) if at all
possible.

I think whichever kernel tree we use, we're going to have to do some
porting either way, so I'd appreciate some guidance as to where in the
kernel I should be looking to resolve the problems we currently have
(as I might need the knowledge gained when we come to adding further
customisations later).

We *do* have a BDI 2000, but I think my ability to be able to debug
this problem is hindered by my limited knowledge of the kernel startup
code.

Any pointers on how to improve that knowledge (URLs, book and the
like), with specific reference to the PowerPC processor, would be much
appreciated.

Thanks to all who have replied thus far.

Andy