[U-Boot] [PATCH 4/4] powerpc: Add LINK_OFF calls in early C-code.

[Wolfgang Denk]

Dear Scott Wood,

In message <20110118142416.5892ca00 at udp111988uds.am.freescale.net> you wrote:
>
> > If we are talking about _all_ boards we have to keep a wider view.
> > For example, on MPC8xx there are not BATs. Not to mention other
> > architectures.
> 
> I don't see why MPC8xx's MMU couldn't be used for this, although it
> might be a tight fit if you want to get everything into the pinned TLB
> entries.

I just wanted to point out that the "use BATs then" approach is also
not a solution that covers all systems.

> Should we be talking about all boards, if the only user of this so far
> is on hardware that can do it in a less-intrusive way?

In the first round of discussion the buzz word was to acchieve a fully
position independent U-Boot image.  This would obviously have a number
of nice use cases, including the often asked for "load test version to
free area in RAM and jump to it".

This is somehting that would indeed be useful for all boards, on all
architectures, all SoCs.  So it makes sense to me to include into the
reviewing  if a proposed solution is capable of being generalized to
other boards / systems or not.

> Another thing to keep in mind is that Joakim's approach also won't work
> on all boards -- you need hardware that is capable of selecting from
> different entry points, where the entry address itself changes rather
> than flash banks being flipped around.

There could be other mechanisms in place to determine which U-Boot
image should be started, like a tiny piece of software that jumps to
the selected image.

Best regards,

Wolfgang Denk

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