generating a phandle w/libfdt?

Kumar Gala galak at kernel.crashing.org
Tue Oct 28 01:15:38 EST 2008


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?

- k




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