[OE-core] Updating u-boot for oe-core or meta-yocto

[Darren Hart]

I've started pulling in the 15 or so patches to u-boot from meta-ti. In
doing so I've come across some questions I'd like you thoughts on.
Specifically, where to put these changes. Some points of context:

1) oe-core is intended to support emulated machines only
2) oe-core has a "virgin" u-boot recipe (no patches)
3) meta-yocto does not have a u-boot recipe (no bbappend either)
4) meta-ti has it's own u-boot recipe with per-machine patches

A stated goal was to bring the Yocto Project's u-boot support for the
Beagleboard in line with that in meta-ti. There are several ways I can
go about this.

a) create a bbappend in meta-yocto and duplicate the meta-ti
   modifications in bbappend form.
b) Modify the oe-core recipe directly

While a) is the most direct approach to accomplish our goal, it requires
continual maintenance and duplicates effort. I don't care for this
approach. b) has the potential to consolidate all beagleboard u-boot
recipe work into a single place. It could simplify the meta-ti and
eliminate the need for a bbappend in the meta-yocto layer.

The question of whether bootloaders have a place in oe-core should
probably be addressed. While they aren't needed for the emulated
machines, they are a highly reusable component for real systems, and
that seems justify keeping them in oe-core. Does anyone disagree with
this assessment?

I propose pulling the necessary changes to u-boot from meta-ti into
oe-core. My initial scan suggested the beagleboard patches are mostly
contained to beagle specific source files. I would prefer to pull in all
the patches for all machines into the SRC_URI, rather than divide them
up by machine. This reduces complexity considerably. For the couple of
patches that collide, we would keep those as machine specific.

As a final part of the work, I would include my beagleboard patch status
audit in the included patches and continue to work on reducing the
patches in the recipe for the beagleboard.

Thoughts?

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel