Defining schemas for Device Tree

[jonsmirl at gmail.com]

On Tue, Jul 30, 2013 at 1:19 PM, Stephen Warren <swarren at wwwdotorg.org> wrote:
>
> On 07/30/2013 07:14 AM, jonsmirl at gmail.com wrote:
> > On Tue, Jul 30, 2013 at 6:25 AM, Mark Brown <broonie at kernel.org> wrote:
> >> On Mon, Jul 29, 2013 at 08:30:29PM -0400, jonsmirl at gmail.com wrote:
> >>
> >>> This...
> >>> tx-dma-channel = <&pdma0 7>; /* preliminary */
> >>> rx-dma-channel = <&pdma0 6>; /* preliminary */
> >>
> >>> Probably should be
> >>> dmas = <&pdma0 7>,<&pdma0 6>;
> >>> dma-names = "tx", "rx";
> >>
> >> It should be - the latter is the generic DMA binding.  There's a lot of
> >> bindings in the kernel that predate that but people are currently
> >> working to transfer over, this is one of the examples of instability
> >> that everyone is talking about.
> >
> > Is something similar to this possible in device tree syntax?
> > dmas =  <"tx" &pdma0 7>,  <"rx"  &pdma0 6>;
>
> I /think/ you can physically write that in *.dts, or something very
> similar; with the strings outside the <>:
>
> dmas = "tx", <&pdma0 7>, "rx", <&pdma0 6>;
>
> However, there's been strong push-back (i.e. doing that has not been
> allowed at all) on attempting to mix variable-length strings and
> fixed-length/alignment integer cells in the same property. This is
> primarily because you then can't ensure that the integer cell data is
> aligned in the DTB (dtc and/or the DTB format spec does/requires/allows

Can we turn the strings into string phandles? Then they'd be fixed sized.

That might provide a way to internationalize the strings too.


>
> no alignment padding), and hence have to be much more careful about data
> alignment when parsing the property.




-- 
Jon Smirl
jonsmirl at gmail.com