Re: [Qemu-devel] [PATCH 02/31] dt: add helpers for 2, 3 and 4 cell adds

[Alexander Graf <agraf@suse.de>]

On 06/06/2012 07:01 AM, Peter Crosthwaite wrote:
> On Wed, 2012-06-06 at 01:52 +0200, Alexander Graf wrote:
>> We have device tree helpers that allow us to create single cell (u32)
>> wide properties. However, when creating properties that contain an array of
>> cells, we need to jump through hoops, manually passing in an array with
>> converted endianness.
>>
>> To ease the pain of this a bit, create helpers for the most common array
>> sizes, namely 2, 3 and 4 cells wide properties.
>>
>> Signed-off-by: Alexander Graf<agraf@suse.de>
>> ---
>>   device_tree.c |   30 ++++++++++++++++++++++++++++++
>>   device_tree.h |    9 +++++++++
>>   2 files changed, 39 insertions(+), 0 deletions(-)
>>
>> diff --git a/device_tree.c b/device_tree.c
>> index 94a239e..b1dff4f 100644
>> --- a/device_tree.c
>> +++ b/device_tree.c
>> @@ -117,6 +117,36 @@ int qemu_devtree_setprop_cell(void *fdt, const char *node_path,
>>       return r;
>>   }
>>
>> +int qemu_devtree_setprop_cell2(void *fdt, const char *node_path,
>> +                               const char *property, uint32_t val,
>> +                               uint32_t val2)
>> +{
>> +    uint32_t tmp[] = { cpu_to_be32(val),
>> +                       cpu_to_be32(val2) };
>> +    return qemu_devtree_setprop(fdt, node_path, property, tmp, sizeof(tmp));
>> +}
>> +
>> +int qemu_devtree_setprop_cell3(void *fdt, const char *node_path,
>> +                               const char *property, uint32_t val,
>> +                               uint32_t val2, uint32_t val3)
>> +{
>> +    uint32_t tmp[] = { cpu_to_be32(val),
>> +                       cpu_to_be32(val2),
>> +                       cpu_to_be32(val3) };
>> +    return qemu_devtree_setprop(fdt, node_path, property, tmp, sizeof(tmp));
>> +}
>> +
>> +int qemu_devtree_setprop_cell4(void *fdt, const char *node_path,
>> +                               const char *property, uint32_t val,
>> +                               uint32_t val2, uint32_t val3, uint32_t val4)
>> +{
>> +    uint32_t tmp[] = { cpu_to_be32(val),
>> +                       cpu_to_be32(val2),
>> +                       cpu_to_be32(val3),
>> +                       cpu_to_be32(val4) };
>> +    return qemu_devtree_setprop(fdt, node_path, property, tmp, sizeof(tmp));
>> +}
>> +
> Cant this be generalised to the n case rather than having functional
> replication for 2/3/4 word props?
>
> +int qemu_devtree_setprop_celln(void *fdt, const char *node_path,
> +                               const char *property, uint32_t *vals, int n)

You mean internally? Yeah, probably. Externally? The point of these 
helpers is to make the code look less cluttered. We can already pass in 
an array just fine, but C is quite annoying about generating those on 
the fly, while it's easy to pass in ints as parameters :)


Alex