[U-Boot] [PATCH 1/2] fdt: Allow indicating a node is for U-Boot proper only

[Marek Vasut]

On 2/4/19 3:40 PM, Simon Glass wrote:
> On Mon, 4 Feb 2019 at 03:15, Patrick Delaunay <patrick.delaunay at st.com> wrote:
>>
>> This add missing parts for previous commit 06f94461a9f4
>> ("fdt: Allow indicating a node is for U-Boot proper only")
>>
>> At present it is not possible to specify that a node should be used before
>> relocation (in U-Boot proper) without it also ending up in SPL and TPL
>> device trees. Add a new "u-boot,dm-pre-proper" boolean property for this.
>>
>>
>> Signed-off-by: Patrick Delaunay <patrick.delaunay at st.com>
> 
> Reviewed-by: Simon Glass <sjg at chromium.org>
> 
> There was discussion some time ago about using a property instead:
> 
> chosen {
>    u-boot,dm-spl = <&node1 &node2>;
>     u-boot,dm-tpl = <&node1>;
> };
> 
> At the time I decided that this was more painful since it separates
> out the tag from its node.
> 
> I wonder if that is still true? We do now in fact generally use a
> u-boot.dtsi file to hold these tags.
> 
> I'm not suggesting a change, just raising the question.

It's a good suggestion. In fact, you can then use some tool to walk back
up the tree and only retain the branches which are referenced by phandle
from u-boot,dm-spl/tpl node for U-Boot SPL/TPL DTs. I think that could
save a bit of space too. I wonder if we can even use /omit-if-no-ref/
DTC syntax somehow.

-- 
Best regards,
Marek Vasut