paubert at iram.es
Tue Apr 9 02:03:28 EST 2002
On Mon, 8 Apr 2002, Tom Rini wrote:
> ... And then the pplus stuff ripped out of the 'PReP' support and
> CONFIG_PPLUS converted too. Before we get too far along, I should say I
> actually do like this idea.
Actually, why does CONFIG_PPLUS even exist? They are basically PreP with
an OpenPIC and slightly different (in some cases) MMIO and I/O mapping,
(Side note: on my MVME2xxx boards which are set in PreP mode by the
firmware, I reinitialize the bridge to be CHRP like, just because I need
larger MMIO area for VME but 1Gb of I/O space is overkill).
> It's worth noting why these are done as they are, since I'm not sure you
> quite see why. pmac and chrp fall into the same category as ppcstar,
> which is 'We know the firmware, it can be useful, and we will use it'.
> prep is more along the lines of 'Nothing useful here, but we've been
> loaded, go go go!'. The 'simple' stuff is 95% prep, but with the legacy
> prep workarounds removed. Also, pmac at least spits out 3 or 4 images
> as it is.
Actually, PreP residual data can be useful, if you kow how to interpret it
to find interrupt routing for example.
(Who should have properly submitted his PrePboot code 3 years ago)
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