[U-Boot] SPL loading U-Boot from a FIT

[Simon Glass]

Hi,

(moving to a new thread)

Tom mentioned:

>We _really_ need some way to support more than one board per binary
>before we can move everything to DM only.

We discussed this on IRC but since that doesn't exist as far as the
mailing list is concerned...

The current plan is:

- Adjust build system to optionally build a u-boot.img in FIT format
that includes the U-Boot binary and >1 device tree files
- Adjust SPL to load this
- Add a way for SPL to determine which device tree to select (by
calling a board-specific function)
- Have SPL pass this selected device tree to U-Boot when it starts

Thus we should be able to support more than one board with a single
U-Boot image. Of course this is not a perfect solution (e.g. it is
inefficient since the DTs are likely to be largely the same) but it
should be a good first step.

I'm going to try this out with sunxi initially and plan to get some
patches out by the end of the week.

If you are interested in taking a look before patches are ready, see
u-boot-fdt/spl-working.

Regards,
Simon