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

[Peter Crosthwaite]

On Fri, Jun 8, 2012 at 10:46 PM, Alexander Graf <address@hidden> wrote:
>
> 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...
>

Since the majority of those functions are wrappers around "fdt_" API
calls, perhaps it should be:

s/qemu_devtree_/qemu_fdt_/g

buys you 4 chars, which should minimise the incidence of 80 char
violations when adding _nofail suffixes. Do we have a large number of
lines already between 78-80 chars?

Regards,
Peter

>
> Alex
>