DTB_RESELECT/MULTI DTB with SPL flow

[Simon Glass]

Hi Michal,

On Fri, 11 Jun 2021 at 07:56, Michal Simek <michal.simek at xilinx.com> wrote:
>
> Hi,
>
> I am just trying to wrap my head around DTB_RESELECT feature.

Did you intend to cc the author of that?

Does doc/README.multi-dtb-fit help?

> ZynqMP is using u-boot.itb which is u-boot/atf + a lot of DT files.
> As of now SPL should pick the right one load it predefined location
> which U-Boot proper pickup.
> Others DTBs are not loaded at all.
> This is working fine and I expect it should work like this even with
> DTB_RESELECT enabled because you need to have base DTB for being able to
> do platform detection.
> I have hookup platform detection in embedded_dtb_select and I know which
> board revision I am running at and struggling how to tell u-boot what to do.
>
> What should be the right flow for changing DTB at run time?
> Where they should be stored? I would expect that I need to have FIT
> image in memory for all board revisions and u-boot should be calling
> board_fit_config_name_match() which will decide which DT is correct
> based on board detection done in embedded_dtb_select().

Yes you can use a FIT to hold the DTs. You can also use binman I
suppose (the 'files' entry type perhaps).

Regards,
Simon