Re: [PATCH] libfdt: add address translation support

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On Mon, 2014-05-12 at 16:00 +1000, David Gibson wrote:
> I'm not all that impressed by this translation code - in particular
> the per-bus-type hooks don't make sense to me.  AFAIK the
> interpretation of ranges is not bus specific. I think it will also
> fail in some cases with #address-cells > 2, which is unfortunate.
> 
> I'm about to post my own implementation of address translation.

Well, I came up with the original code which did per-bus type hooks.
There are cases where it is needed.

Take PCI. The top word can contain completely unrelated stuff such
as the "prefetchable" attribute.

It's perfectly legal to put a prefetchable BAR under a non-prefetchable
bridge window.

However a translation scheme that doesn't know to know that bit
will fail.

It's not far fetched, it happens on our machines today.

And that's just one of the problems I had back then...

Cheers,
Ben.


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