generating a phandle w/libfdt?

[David Gibson]

On Mon, Oct 27, 2008 at 09:15:38AM -0500, Kumar Gala wrote:
>
> On Oct 26, 2008, at 6:40 PM, David Gibson wrote:
>
>> On Fri, Oct 24, 2008 at 09:29:21AM -0700, Yoder Stuart wrote:
>>>
>>>
>>>> -----Original Message-----
>>>> From:
>>>> devicetree-discuss-bounces+stuart.yoder=freescale.com at ozlabs.o
>>>> rg
>>>> [mailto:devicetree-discuss-bounces+stuart.yoder=freescale.com@
>>> ozlabs.org] On Behalf Of Kumar Gala
>>>> Sent: Friday, October 24, 2008 9:19 AM
>>>> To: devicetree-discuss
>>>> Subject: Re: generating a phandle w/libfdt?
>>>>
>>>>
>>>> On Oct 24, 2008, at 8:11 AM, Kumar Gala wrote:
>>>>
>>>>> In some work I'm doing I noticed we don't have any APIs to
>>>> generate
>>>>> a phandle via libfdt.
>>>>>
>>>>> was wondering if anyone had ideas on this.
>>>>>
>>>>> In first thought it seems we have to scan through the whole blob
>>>>> looking for the largest phandle id and than +1 it to generate the
>>>>> next "valid" id.  Any other ideas on how to do this more
>>>> efficiently?
>>>>
>>>> The other question is there a way today to create a phandle even if
>>>> there isn't a reference to it elsewhere in a .dts?
>>>
>>> We had this issue and the 'hack' was to create a phandle property
>>> in the node itself, so it was self-referenced.  That caused DTC
>>> to allocate a phandle.   We then could reference the node from
>>> dynamically generated nodes.
>>
>> That's nasty.  I should add a way to make dtc generate a phandle for a
>> node, even if it's not referenced from elsewhere.  Just need to think
>> of a decent syntax.
>
> What if we just have it do that if we have a "linux,phandle" property  
> w/o a value in the .dts?

Hrm.  Normally that would create a property named "linux,phandle" with
a zero-length value.  I'm disinclined to special case this.

Hrm, it occurs to me that:
	foo: node {
		linux,phandle = < &foo >;
	};
might well work right now, though it's a bit horrible from the
implementation side.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson