Re: [PATCH 3/4] arm: dts: k3-*-binman.dtsi: Clean up and templatize boot binaries

["Michael Walle" <mwalle@kernel.org>]

Hi,

On Wed Mar 27, 2024 at 8:01 AM CET, Neha Malcom Francis wrote:
> On 26/03/24 19:18, Michael Walle wrote:
> > On Fri Mar 22, 2024 at 2:10 PM CET, Neha Malcom Francis wrote:
> >> Clean up templatized boot binaries for all K3 boards. This includes
> >> modifying the k3-binman.dtsi to use SPL_BOARD_DTB, BOARD_DESCRIPTION and
> >> UBOOT_BOARD_DESCRIPTION from the files that include it to further reuse
> >> code.
> >>
> >> All k3-<soc>-binman.dtsi will contain only templates. Only required boot
> >> binaries can be built from the templates in the boards' respective
> >> -u-boot.dtsi file (or k3-<board>-binman.dtsi if it exists). This allows
> >> clear distinction between the SoC common stuff vs. what is additionally
> >> needed to boot up a specific board.
> > 
> > I appreciate the cleanup. But as far as I can see, a board might
> > only have one device tree. How would that work if the uboot proper
> > must support multiple device trees?
> > 
>
>  From the discussions that took place in the mailing list [1] the consensus 
> seems to be to not focus on multiple devicetree support as it leads to confusion 
> for downstream users.

What are users in this regard? I don't think you'd confuse
developers.

Anyway, I'm planning on upstreaming a TI board which will have
different memory configurations and different variants of the board.
And on top of that, it will just be a base board and there will
likely be some carrier device trees (overlay? I'm not sure yet).

As far as I can tell, you've put the memory configuration into the
device tree, so I'll probably need to switch between them somehow.
Also, regarding the board variants, I'll probably need to choose
between multiple device trees. That is invisible to the user,
because u-boot will choose the correct DTB according a board
strapping, which btw. works really fine, see for example
(boards/kontron/sl28/spl.c:board_fit_config_name_match).

I don't think it makes much sense to hardcode your generic
*-binman.dtsi to just one FIT configuration. I'd rather see a split
between generic things which are shared across all boards and board
specifics, like the FIT configuration. I mean I could just copy all
the binman and tiboot3.bin and tispl.bin magic and put it into my
own "-u-boot.dtsi". But I'm not sure that will make things any
better.

-michael