Re: [Qemu-ppc] [Qemu-devel] [PATCH 05/31] dt: add helper for phandle enumeration

[Peter Crosthwaite]

On Thu, Jun 7, 2012 at 1:58 AM, Alexander Graf <address@hidden> wrote:
> On 06/06/2012 07:11 AM, Peter Crosthwaite wrote:
>>
>> On Wed, 2012-06-06 at 01:52 +0200, Alexander Graf wrote:
>>>
>>> This patch adds a helper to search for a node's phandle by its path. This
>>> is especially useful when the phandle is part of an array, not just a
>>> single
>>> cell in which case qemu_devtree_setprop_phandle would be the easy choice.
>>>
>>> Signed-off-by: Alexander Graf<address@hidden>
>>> ---
>>>  device_tree.c |   16 +++++++++++++++-
>>>  device_tree.h |    1 +
>>>  2 files changed, 16 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/device_tree.c b/device_tree.c
>>> index 6cbc5af..6745d17 100644
>>> --- a/device_tree.c
>>> +++ b/device_tree.c
>>> @@ -162,10 +162,24 @@ int qemu_devtree_setprop_string(void *fdt, const
>>> char *node_path,
>>>      return r;
>>>  }
>>>
>>> +uint32_t qemu_devtree_get_phandle(void *fdt, const char *path)
>>> +{
>>> +    uint32_t r;
>>> +
>>> +    r = fdt_get_phandle(fdt, findnode_nofail(fdt, path));
>>> +    if (r<= 0) {
>>> +        fprintf(stderr, "%s: Couldn't get phandle for %s: %s\n",
>>> __func__,
>>> +                path, fdt_strerror(r));
>>> +        exit(1);
>>
>> Is it really this functions job to terminate qemu on fail?  There may be
>> scenarios where a node does not have a phandle where the client can
>> handle that. Perhaps return -1 on error and the client has to check?
>
>
> If it can, what's the point in not calling libfdt directly then?
>

Its a very good question. If the point of this function is to fail of
error though, perhaps it should have the _nofail suffix for clarity?

>
> Alex
>