Re: [Qemu-devel] [PATCH 2/4] Add device tree machine

[Gerd Hoffmann <kraxel@redhat.com>]

On 06/11/09 15:39, Paul Brook wrote:
> On Thursday 11 June 2009, Gerd Hoffmann wrote:
>> Where do device properties come from?  Only the fdt tree?  If so, do we
>> need the property lists in the first place?  We could get them directly
>> from the fdt tree instead.
>
> The FDT doesn't contain any type information.

Which isn't a issue IMHO.  The driver which needs the value knows the 
type to expect, doesn't it?

To outline in more detail what I mean:

Now we have (picking an example with int type):
   dt_add_props(), calling
     fdt_getprop() + fdt32_to_cpu() + qdev_set_prop_int().
And
   i2c_slave_qdev_init(), calling
     qdev_get_prop_int().

I think instead we can do:
   Have a helper named --say -- qdev_get_fdt_int(), calling
     fdt_getprop() + fdt32_to_cpu(), returning an int.
Then have
   i2c_slave_qdev_init() calling
     qdev_get_fdt_int().

i.e. don't extract and save the properties at all, instead have helper 
functions to get them directly from the fdt tree.

cheers,
   Gerd