[U-Boot] Add support for imxrt

[Fabio Estevam]

Hi Giulio,

On Fri, Sep 27, 2019 at 11:57 AM Giulio Benetti
<giulio.benetti at benettiengineering.com> wrote:

> While porting IMXRT I'm realizing that things would fit better if adding
> to mach-imx folder. This is because IMXRT has a lot in common with imx
> on low level side, i.e. iomux, clock. So I would go for mach-imx instead
> of mach-imxrt, is it ok?

Yes, that is fine.

> But then I can't understand if going on trying to initialize everything
> through dts, even on SPL, or trying to imitate how other imx work, i.e.
> imx6 where they directly call low-level functions(iomuxc etc.) in board
> init.
> Which approach would be better for you all?

We try to use DM in U-Boot proper as much as possible, but using DM in
SPL is currently not a requirement, especially due to internal RAM
size constraints.

Regards,

Fabio Estevam