Organisation of 4xx initialization code

Tom Rini trini at
Sat Nov 17 02:51:21 EST 2001

On Fri, Nov 16, 2001 at 04:57:38AM -0700, Matt Porter wrote:
> On Fri, Nov 16, 2001 at 04:46:26PM +1100, David Gibson wrote:
> >
> > At the moment the initialization for each of the 4xx boards goes
> > through the platform_init() in arch/ppc/kernel/ppc4xx_setup.c, which
> > in turns calls a board_init() function for the specific board.
> >
> > It seems to me that it would make more sense to put platform_init() in
> > the board specific files, and these functions could then call back,
> > where appropriate, to generic 4xx setup functions.  This would mean:
> > 	- It would be easier to support wierd and wacky boards which
> > have non-standard address setups.
> > 	- Some ugly #ifdefs in ppc4xx_setup.c could be done away with.
> > 	- We should be able to remove some inconvenient header
> > dependencies - at present lots of things are recompiled when board
> > local defines are changed because walnut.h/ep405.h/etc are included
> > indirectly in serial.h and some other unexpected places.
> >
> > Thoughts?
> I've been wondering why it's architected that way as well.  It
> seems you are looking for it to follow the model of the well
> abstracted 7xx/74xx ports.  Examples are the ones that rely on
> mpc10x_common and pplus_common as libraries of common initialization
> code (MEN F1, PCore, MCPN765, MVME5100, etc.).

But that's just it.  Someone else should probably speak up on this, but
in the 403/405/stb0{3,4}xxx, and possibly 440 when it exists there are
some things which always exist, depending on processor.  Each 750 board
for example can really have almost anything attached to it.  But for a
405GP, there are known things and some variable things.  I _think_ 4xx
boards vary more like the 8xx ones do, than 750 does.

Having said that, there is room for imporvement, but I think it's more
along the lines of moving more things into board_init which can override
the default structs if needed.

Tom Rini (TR1265)

** Sent via the linuxppc-embedded mail list. See

More information about the Linuxppc-embedded mailing list