Re: [Xen-devel] [PATCH v4 30/33] tools/libxl: arm: Use an higher value for the GIC phandle

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Ian,

On 31/03/15 12:43, Ian Campbell wrote:
> On Thu, 2015-03-19 at 19:29 +0000, Julien Grall wrote:
>> The partial device tree may contains phandle. The Device Tree Compiler
>> tends to allocate the phandle from 1.
>>
>> Reserve the ID 65000 for the GIC phandle. I think we can safely assume
>> that the partial device tree will never contain a such ID.
>>
>> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
>> Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
>> Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
>>
>> ---
>>     It's not easily possible to track the maximum phandle in the partial
>>     device tree.
>>
>>     We would need to parse it twice: one for looking the maximum
>>     phandle, and one for copying the nodes. This is because we have to
>>     know the phandle of the GIC when we create the properties of the
>>     root.
> 
> Or you could fill it in post-hoc like we do with e.g. the initramfs
> location?

That would work. I will see for a follow-up of this patch series.

> Anyway, this'll do for now:
> Acked-by: Ian Campbell <ian.ampbell@xxxxxxxxxx>
> 
>>
>>     As the phandle is encoded an unsigned 32 bits, I could use an higher
>>     value. Though, having 65000 phandle is already a lot...
>>
>>     TODO: If it's necessary, I can check if the value has been used by
>>     another phandle in the device tree.
> 
> If that's easy enough to add then yes please, but if it is complex then
> don't bother.

I would prefer to postpone and replace with a follow-up to allocate
dynamically the phandle.

Regards,

-- 
Julien Grall

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