Porting to Compact PCI

[Peter Grehan]

Hi Aron,

> 1.  Boot Linux using U-Boot on this board.

 I suspect this will be an easy step.

> 2.  Try U-Boot and FreeBSD.  I think that this will require a bunch of
> U-Boot specific stuff as well as some board specific drivers that could also
> be merged with FreeBSD-PowerPC.  This should also firm up FreeBSD support in
> general under U-Boot.

 The main issue with U-Boot is that it doesn't export a low-level driver interface,
which the loader really wants to see. The alternative is to implement polled-mode
drivers in loader, which is really replicating what U-Boot already does, so I
think the best path is to extend U-Boot's "syscall" interface to allow access
to it's existing driver code.

> 3.  Once U-Boot gets to the point where it is trying to boot a FreeBSD
> kernel, plug away at the Harrier ASIC, Flash memory, and any other
> peripheral support needed by the board and merge with FreeBSD-PowerPC.  The
> MCIP805 programmer's manual contains a good list of components and has links
> to additional documentation.

 The PPC port is currently way too tied to OpenFirmware, but it's always been known
that this has to be split out.

 Another issue is JFFS2 support in FreeBSD, which is what U-Boot uses for
it's flash filesystem. This would probably involve ext2fs-like copyright
issues.

> Let me know what everybody thinks.

 It's an excellent plan, and will help to realise the ultimate goal of the PPC
port which was embedded systems. It is very handy to have a fast G4 Mac for
native builds though :-)

later,

Peter.