RFC: Location for Device Tree Sources?

Li Yang LeoLi at freescale.com
Fri Aug 4 00:49:11 EST 2006

On 8/3/06, Kumar Gala <galak at kernel.crashing.org> wrote:
> On Aug 2, 2006, at 1:57 PM, Tom Rini wrote:
> > On Wed, Aug 02, 2006 at 01:23:08PM -0500, Jon Loeliger wrote:
> >> On Wed, 2006-08-02 at 13:21, Tom Rini wrote:
> >>
> >>> Yes, as I said, I'm not totally sure we're at the stable point right
> >>> now, but I think that we are.  I'll add that maybe we need to think
> >>> about API changes and DTS format versions.  To quote from my post..
> >>>
> >>>>> X bugs) or a change that requires a dts version bump.
> >>>
> >>> Now it sounds like the IRQ thing was an "Oops, we should have
> >>> changed
> >>> the dts version" and bailed, noting what is wrong with the dts.
> >>
> >> This confuses me.  There hasn't been a change in the DTS
> >> format at all.  I've even updated the 8641HPCN DTS file
> >> across the IRQ updates and all is fine.  Same (DTS) format
> >> both before and after the IRQ changes.
> >>
> >> What have I missed here?
> >
> > Matthew said:
> >> The sandpoint (as far as I know) does not have a stable DTS. So in
> >> this
> >> case including the DTS in the kernel would reduce confusion. The same
> >> could be said for other boards where the DTS needed to be changed for
> >> the IRQ rework. The old DTS will no longer boot the new kernels.
> >> I'm not
> >> sure how much longer we will run into this problem though.
> >
> > Now, if we've had to change the contents of the DTS because of a
> > kernel
> > change, I'd say the DTS format changed as when I say format I mean not
> > only layout and naming, but what the contents are supposed to contain.
> >
> > And, so it's clear, I don't know if we're at the very stable format
> > (names/layout/content means...), but when we are at that point, what
> > Matthew noted should, IMHO, be a graceful (ie explained in the panic()
> > or something) death.
> >
> > And, so it's clear, I think (and hope!) we all agree on that last
> > part,
> > once we hit stability.
> Agree about the comments related to the stability of the API, I just
> dont think we are there yet.  We should revisit the issue when we
> removed arch/ppc, until that point I would say things are up in the air.
> For example, we still haven't closed on CPM descriptions and I'm sure
> we will go through several iterations before we get it right.  For
> more standard things like uart's, ethernet, pci we have the OF specs
> to model off of and are probably pretty stable.

I agree.  We are adding more and more device types under device tree
management.  There will be a process of evolution.
> Additionally, Ben and I have talked about making macro's in the dts's
> so we can build up a board or SOC description from standard building
> blocks so people dont get the simple things wrong.

What are the macros about? Like constant we used in source code?
> - kumar
- Leo

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