Merging ppc32 and ppc64
trini at kernel.crashing.org
Wed Aug 10 02:21:33 EST 2005
On Tue, Aug 09, 2005 at 10:01:05AM -0500, Kumar Gala wrote:
> >I think you are both right, just using different terminology. The
> >running kernel uses its own representation of the device tree, which
> >is neither the flattened stuff nor using the OF interfaces. The
> >conversion from OF to the flattened tree is done by the kernel itself.
> > Apple OF \
> > SLOF \
> > pSeries |-1- prom_init------,
> > PIBS / \
> > ... / \
> > \
> > other -----------------------------2--
> > boot loader /
> > /
> > iSeries ----------- early_setup---`
> >All "regular" machines enter in the traditional prom_init path (1)
> >from Open Firmware. The embedded machines that are too memory
> >to use SLOF have a flattened device tree in their boot loader and the
> >legacy iSeries boxes can fake the device tree in their
> >function. The main entry point (2) is entered by all machines when the
> >flattened device tree is there and the kernel builds its tree
> >for run time (3).
> I guess my point is that in the "new" powerpc arch doing steps 1 & 3
> should no longer be part of the kernel proper. The should be handled
> by boot wrappers of some form. I know Ben tool care to ensure that
> prom_init was isolated from kernel proper and I'm suggesting we move
> it into a boot wrapper going forward.
That's not 100% true because as Segher said, prom_init.c is part of the
kernel (tree, image), but is what does the translation.
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