Re: [Qemu-devel] [PATCH 07/31] dt: add helper for phandle allocation

[Alexander Graf <agraf@suse.de>]

On 06/06/2012 07:18 AM, Peter Crosthwaite wrote:
> On Wed, 2012-06-06 at 01:52 +0200, Alexander Graf wrote:
>> Phandle references work by having 2 pieces:
>>
>>    - a "phandle" 1-cell property in the device tree node
>>    - a reference to the same value in a property we want to point
>>      to the other node
>>
>> To generate the 1-cell property, we need an allocation mechanism that
>> gives us a unique number space. This patch adds an allocator for these
>> properties.
>>
>> Signed-off-by: Alexander Graf<agraf@suse.de>
>> ---
>>   device_tree.c |    7 +++++++
>>   device_tree.h |    1 +
>>   2 files changed, 8 insertions(+), 0 deletions(-)
>>
>> diff --git a/device_tree.c b/device_tree.c
>> index d4f1f0a..317bdd0 100644
>> --- a/device_tree.c
>> +++ b/device_tree.c
>> @@ -220,6 +220,13 @@ int qemu_devtree_setprop_phandle(void *fdt, const char *node_path,
>>       return qemu_devtree_setprop_cell(fdt, node_path, property, phandle);
>>   }
>>
>> +uint32_t qemu_devtree_alloc_phandle(void *fdt)
>> +{
>> +    static int phandle = 0x8000;
> can easily double check for duplicates. Would also allow you to start
> from 1 rather than magic number 0x8000?
>
> while (fdt_node_offset_by_phandle(fdt, phandle) != FDT_ERR_NOTFOUND)
>      phandle++;

That's a nice one. It'd even allow us to drop the external phandle 
starting id patch.

Scott, would this work for you?


Alex