Re: Call for Testing: Switching back to our BSD licensed dtc(1)

On Fri, 22 Jul 2016 22:16:41 -0600
Warner Losh <imp_at_bsdimp.com> wrote:

> On Fri, Jul 22, 2016 at 1:03 AM, David Chisnall <theraven_at_freebsd.org> wrote:
> > On 22 Jul 2016, at 03:40, Warner Losh <imp_at_bsdimp.com> wrote:
> >>
> >> On Wed, Jul 20, 2016 at 9:51 AM, David Chisnall <theraven_at_freebsd.org> wrote:
> >>> On 20 Jul 2016, at 16:46, Warner Losh <imp_at_bsdimp.com> wrote:
> >>>>
> >>>> I've been trying to get the final spec for it. Right now it's a
> >>>> disorganized series
> >>>> of patches, some of which have been merge some that haven't. I'll send you a
> >>>> copy when I can find something better than "here's the code."
> >>>
> >>> Thanks.  From the information I can find, it looks as if most of the machinery required to implement it is already in dtc, so it should (hopefully) just be a matter of adding a new keyword to detect plugins, a scan to find the cross-references (or possibly reusing the existing one) and then a little bit of extra logic.
> >>
> >> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/overlay-notes.txt
> >> has the specs.
> >
> > Hmm, that?s even less complete than the docs that I?d found.
> 
> Can you share that then?
> 
> >From that, it seems as if the only thing that dtc needs to do is support the /plugin/ syntax and emit a section describing unresolved references?
> 
> I believe so, yes.
> 
> >Or is dtc also expected to be able to do the merging?
> 
> I think that's TBD. We'll need, at the very least, an update libfdt
> from upstream that knows how to do the merging, as well as changes to
> /boot/loader to be able to pick and choose which plugins to add to the
> base. If we can do all that with the BSDL DTC and it passes all the
> other GPL test cases, then we may have a winner and we can get started
> integrating plugin support to /boot/loader. I know my RPi would be
> happier if it had a 'standard' DTB with a plugin for whatever 1-wire
> stuff I'm playing with today.
> 
> Warner

 ubldr already support dtb overlays as of r298821.
 Also support might come to uboot directly soon.

-- 
Emmanuel Vadot