Booting the Linux/ppc64 kernel without Open Firmware HOWTO(#2)

[Tzachi Perelstein]

Seems like it was a *hot* weekend...

Ben, I agree with Wolfgang that while taking footprint and simplicity
into account we should "try to think about the whole system, including
boot loader, kernel, and any data that might need to get passed between
these two". 

My ppc64 Linux is booted from U-Boot on Marvell platform and it uses the
simple board_info instead of the device-tree. There are only some minor
hacks in arch files that by-pass the whole device-tree usage in head.S
and setup.c, e.g. [1] early_init_board_info() instead of
early_init_devtree(), and [2] skipping on unflatten_device_tree() and
finish_device_tree(). As you know, the majority of these functions and
sub-functions just parse and handle the device-tree. 
Frankly, although I'm willing to give device-tree a try, I think it is
not the wise thing to do. It is simple and effective, and it can be
nicer with minor _general_ support in arch files to non-OF loaders. A
slightly different loading for embedded systems is not necessarily a
mess. I'm sure that the ppc experience will make it be nice and
structured even this way.

Imagine emerging ppc64 Linux embedded systems living outside the kernel
due to embedded incompatibilities; this might make much more mess in the
long run... 

Best Regards,
Tzachi