Re: [Qemu-devel] [PATCH 5/7] hw/core/sysbus: add fdt_add_node method

[Eric Auger]

On 07/08/2014 03:52 PM, Alexander Graf wrote:
> 
> On 07.07.14 09:08, Eric Auger wrote:
>> This method is meant to be called on sysbus device dynamic
>> instantiation (-device option). Devices that support this
>> kind of instantiation must implement this method.
>>
>> Signed-off-by: Eric Auger <address@hidden>
> 
> For the reason I stated earlier, I don't think it's a good idea to put
> device tree code into our device models.

Hi Alex,

I would propose we discuss that topic during next KVM call if you are
available. Hope Peter will be available to join too. Because I feel
stuck between not putting things in the machine file (1) - obviously we
could put them in a helper module (2) - and not putting them in the
device (3).

Whatever the solution I fear we are going to pollute something: Any time
a new device wants to support dynamic instantiation, we would need to
modify the machine file or the helper module with 1 and 2 resp. In case
we put it in the device we pollute this latter...

My hope was that quite few QEMU platform devices would need to support
that feature and hence would need to implement this dt node generation
method. To me dynamic instantiation of platform device was not the
mainstream solution.

Then there is the fundamental question of technical feasibility of
devising a generic PlatformParams that match all the specialization
needs? Here I miss experience. In case we know the machine type and a
small set of additional fields couldn't we do the adaptations you talked
about, related to IRQs?

Best Regards

Eric

> 
> 
> Alex
>