Devicetree Maintenance in barebox

[Sascha Hauer]

On Fri, Feb 07, 2014 at 11:39:33AM +0400, Alexander Shiyan wrote:
> Hello.
> 
> Пятница,  7 февраля 2014, 8:13 +01:00 от Sascha Hauer <s.hauer at pengutronix.de>:
> > Hi All,
> > 
> > It's becoming more obvious that devicetree maintenance is painful
> > because we have to sync them to the kernel regularly. My hope was that
> > this would get simpler once the devicetrees get their own repository
> > outside the kernel, but it seems that won't happen anytime soon.
> > 
> > So my current idea to continue with barebox devicetrees is:
> > 
> > - Maintain a kernel branch which has all devicetree changes we need in
> > barebox in a clean step-by-step series
> > - rebase this branch regularly on the newer kernel
> > - Copy the resulting devicetrees to barebox
> > 
> > The upside is that we have up to date devicetrees in barebox without
> > having to resync them by hand on a per SoC basis.  Of course this also
> > means that we lose the devicetree history and breakage may be introduced
> > with some huge commits saying "Update devicetrees to Linux-3.x".
> > 
> > Any better ideas? I think we have to do something.
> 
> As far as I know, in the community have any thoughts on the transfer of the DT data
> in a separate project, but most likely it will not be soon ...

Yeah, I also don't think this will happen soon. Even if it does I think
this won't solve all problems. We will still need barebox specific
adjustments.

> 
> At the moment, I want to suggest to use only non-modified DT files, i.e. barebox
> should use to build their own files, which include the original data from the kernel.
> 
> Just for example:
> # ls
> bb_<board.dts>
> <board.dts>
> 
> # cat bb_<board.dts>
> 
> #include "<board.dts>"
> /* All overrides here */
> chosen {
>   ...
> };

I like the idea. One disadvantage may be that the structure in the dts
directory gets more unclear, but I guess we can't have everything.

Sascha

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