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

[Alexander Graf]

On 07.06.2012, at 02:28, Peter Crosthwaite wrote:

> 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?

If we do a global s/qemu_devtree_/qdt/g throughout the code base, I'd be open 
to add _nofail to all function names at the end :). Otherwise we'll get into 
even more trouble of staying within 80 characters per line...


Alex