RFC: Location for Device Tree Sources?

Kumar Gala galak at kernel.crashing.org
Thu Aug 3 06:06:34 EST 2006

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.

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.

- kumar

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