Re: [PATCH 0/7] of: overlay: Add support for export-symbols node feature

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Jan 10, 2025 at 01:25:43PM +0530, Ayush Singh wrote:
> 
> 
> On 10/01/25 09:56, David Gibson wrote:
> > On Wed, Jan 08, 2025 at 10:47:19AM +0100, Herve Codina wrote:
> > > Hi Ayush,
> > > 
> > > On Wed, 8 Jan 2025 13:58:04 +0530
> > > Ayush Singh <ayush@beagleboard.org> wrote:
> > > 
> > > ...
> > > > 
> > > > I will experiment with adding support to dtc and see how things look.
> > > > Hopefully, 2025 is the year of addon board support.
> > > > 
> > > 
> > > Also one point different between fdtoverlay an runtime loading is
> > > that runtime loading allows to set the target node of the overlay
> > > at runtime.
> > 
> > I'm not really sure what you mean by "runtime loading".  Do you mean
> > the kernel's implementation of loading dtbo overlays?
> > 
> > While that is a different implementation from the one in fdtoverlay
> > (AIUI), they're both working from the same dtb format.  As we
> > discovered attempting Ayush's proposal, it turns out that the dtbo
> > simply doesn't have the information we need to correctly path
> > substitutions; and it's not at all easy to add it.
> 
> Ahh, I think there is a misunderstanding. `export-symbols` only seems to
> support phandles, not paths. So no resizing involved.

Oh, sorry, I was mixing this up with a different feature Ayush was
working on.

> It's closer to the phandle support in `__symbols__`, just local in scope.
> 
> > 
> > So, the problem of the encoding format needs to be solved regardless
> > of which implementation is actually processing the overlays.
> > 
> 
> So there is no problem with the encoding format.
> 
> The questions I have are more regarding weather `export-symbols` or
> something close to it can be made part of spec instead of the custom linux
> thing.
> 
> 
> Ayush Singh
> 

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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