Messages in this thread | | | Date | Thu, 21 Jan 2021 11:04:26 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH V5 5/5] of: unittest: Statically apply overlays using fdtoverlay |
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On 20-01-21, 23:14, Frank Rowand wrote: > It is a convenient FDT to use because it provides the frame that the overlays > require to be applied. It is fortunate that fdtoverlay does not reject the use > of an FDT with overlay metadata as the base blob.
> This is probably a good idea instead of depending on the leniency of fdtoverlay.
I believe fdtoverlay allows that intentionally, that would be required for the cases where we have a hierarchy of extension boards or overlays.
A platform can have a base dtb (with /plugin/;), then we can have an overlay (1) for an extension board (with /plugin/;) and then an overlay (2) for an extension board for the previous extension board.
In such a case overlay-(2) can't be applied directly to the base dtb as it may not find all the nodes it is trying to update. And so overlay-(2) needs to be applied to overlay-(1) and then the output of this can be applied to the base dtb.
This is very similar to what I tried with the intermediate.dtb earlier.
-- viresh
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