On Fri, Apr 28, 2006 at 11:01:20AM -0500, Kumar Gala wrote:

However, I really hate introducing some third project that is  
required.  If we decide to pull ALL of boot wrappers out of the  
kernel tree than I'd be ok with it.  But until that time I think this  
lives under arch/powerpc/boot/...

The more I think about this, and hear about what some vendors do,
pulling arch/p*pc/boot/ out of the kernel is making more and more sense.
Especially with the serial headache, a depends-on-nothing,
can-translate-$(firmware information) tool might be best.

What I envision as the way one boots for something like u-boot is one  
of three options:
1. using an old u-boot + boot wrapper (bd_t -> wrapper -> kernel)
2. using a u-boot that is ft aware + dtb (boot command in u-boot  
takes kernel & dtb images, updates blob and passes to kernel)
3. using a u-boot that is ft aware + built in dtb.

And more generally:
1. using an old firmware + kernel boot wrapper (firmware->dtb converter)
boots kernel.
2. using a dtb-aware firmware boots kernel (compressed or not) and
passes dtb in.

The issue is that for a given system/board you may need to support  
multiple or all three.  This raises the question where does the .dts  
live.  For the time being I say it lives in the boot wrapper part of  
the kernel tree.  Thus we handle the three cases as follows:

We could stick it in the seprate kernel boot wrapper project.  But I
really think this really has to live in two places.  The kernel should
be The Owner, as until *BSD or something adopts this, it's a
Linux-specific thing.  But any firmware that wishes to skip the kernel
boot wrapper and be a direct kernel booter, will need to own a copy.

-- 
Tom Rini
http://gate.crashing.org/~trini/