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

On Tue, Jul 19, 2016 at 1:12 PM, Ed Maste <emaste_at_freebsd.org> wrote:
> dtc(1) is the Device Tree Compiler, used for embedded builds. We have
> two versions of dtc(1) in the FreeBSD tree: a GPLv2 one from
> https://git.kernel.org/cgit/utils/dtc/dtc.git and a BSD licensed one
> in https://svn.freebsd.org/base/head/usr.bin/dtc.
>
> We switched back to the GPL one since device tree files in the most
> recent import required features not available in our own at the time.
> However, as of r292876 the BSD licensed dtc(1) is functional and we
> should be able to switch back to it.
>
> I would encourage embedded users (primarily ARM boards) to test with
> WITHOUT_GPL_DTC in /etc/src.conf and report their success or failure.

My concern with this is overlay support. Overlay support for "shields" or
"badges" is going into upstream GPL dtc shortly. The patches have been
kicking around for a while and are almost ready to go in. We need this feature
and I'd planned on bringing it into the tree as soon as it goes into the git
repo. It's sorely needed for things like RPi and BBB that make it super
easy to add boards with parts that need a bit more DTB into the FDT to
describe them. There's been patches to bring this functionality into the
loader and into the in-tree gpl dtc floating around for a while now.

I know that the BSDL compiler doesn't support this. I know from painful
experience that the BSDL compiler is quite hard to fix grammar items
for since it doesn't use yacc, but uses a hand-coded parser / lexer. If
support could be added for this to that, we can throw the switch. Otherwise,
I don't think that it would be wise to switch.

Last time I ran my tests on the BSDL compiler, it failed a few of them. I'll
re-run to see if things have improved since I last checked it out and report
any failures here.

Warner