[PATCH] spl: fit: List DTOs applied by SPL in U-Boot control DT

[Quentin Schulz]

Hi Marek,

On 6/30/24 4:33 AM, Marek Vasut wrote:
> On 6/28/24 10:27 AM, Quentin Schulz wrote:
> 
> Hi,
> 
>>>> Shouldn't this rather be in /config node?
>>>
>>> This is what I had there originally, but then I realized that some 
>>> DTs might not have the /config node in them (or am I mistaken?), so I 
>>> moved the new properties into the root node, which surely exists.
>>>
>>> It also keeps the code simpler, as it doesn't have to fiddle with 
>>> creation of the /config node if it doesn't exist.
>>>
>>
>> I don't think we should pollute the root node with this. If we want to 
>> be able to expose this in a proper binding to the upstream DT binding 
>> repo, I'm not sure this is going to fly :/
> 
> The other option is to add more code into SPL, that's not great.
> 
> I can check if /config node exists, and if so, add it there, otherwise 
> do nothing. That should be some sort of compromise between bloat and 
> config node. What do you think ?
> 
> [...]
> 

Considering that we're trying to have the same DT for U-Boot and Linux 
kernel in the long run and that `git grep "\s+config {"` returns nothing 
in dts/upstream/src, I'm not sure this amounts to anything but 
dead-code? We could also always insert this node as pre/post process of 
the DT compilation? But I think some people want to reuse the exact same 
DTB (like, the binary itself) between U-Boot and the Linux kernel.

I guess we can start with checking if the /config node exists and we can 
figure something smarter once we need it?

[...]

>> 2- Add info about which DTBOs were applied to the kernel DTB?
> 
> SPL DTOs or DTOs applied from kernel fitImage ? Or a merging of those ?

DTOs that U-Boot proper applies to the kernel DTB either via fitimage 
configs, maybe also via syslinux (via 
`fdtoverlays`/`devicetree-overlay`) and the like?

Cheers,
Quentin