Re: [PATCH 0/5] ARM: orion5x/dove/mv78xx0 multiplatform

Josh Triplett
2015-12-11T18:27:38Z

On Fri, Dec 11, 2015 at 01:36:01PM +0000, Jason Cooper wrote:
> +Josh
>
> Hey Arnd, Detlef,
>
> On Fri, Dec 11, 2015 at 12:10:55AM +0100, Arnd Bergmann wrote:
> > On Thursday 10 December 2015 23:00:24 Detlef Vollmann wrote:
> > > On 12/10/15 22:29, Arnd Bergmann wrote:
> > > > On Thursday 10 December 2015 22:14:25 Detlef Vollmann wrote:
> > > >> On 12/10/15 21:59, Arnd Bergmann wrote:
> > > > It may also be worth investigating what has made CONFIG_OF so costly,
> > > Probably because too much is done at runtime and too few things can
> > > be fixed at build time.
> > >
> > > > maybe we can reduce this a bit again.
> > > Probably not without turning the wheel backward :-(
> > >
> > > So for the test: yes it works, but I'm unhappy with it.
> >
> > I'm not too happy about adding 80kb to the uncompressed kernel
> > image either. I've spent some more time now trying to find where
> > we added the bloat. It's mainly in drivers, not in arch specific
> > code, a kilobyte here and there eventually adds up, but the largest
> > portion with a little over 50% of the total diff is drivers/of.
>
> Wasn't there an idea kicked around a while ago to create a
> dt2boardfile script/executable*? Then, during kernel configuration, you
> enable it and select which dts file you want. It would disable
> CONFIG_OF, multiplatform, etc. And generate a board_file.c from the dts
> file.
>
> If anything, it might be worth asking the kernel tinification [1], [2]
> folks if they'd be interested in taking this on...

No objection if you want to add it to the task list on
tiny.wiki.kernel.org (on the more difficult end).

I don't know if you could generate a board file, but I do wonder if you
could effectively compile in a parsed description and ditch the parser.
Bonus if you can make the values parsed out of it into compile-time
constants for constant folding.