Re: [Qemu-devel] [PATCH v3 2/6] hw/arm/dyn_sysbus_devtree: helpers for sysbus device dynamic dt node generation

[Eric Auger <eric.auger@linaro.org>]

On 09/09/2014 06:00 PM, Peter Maydell wrote:
> On 9 September 2014 16:56, Eric Auger <eric.auger@linaro.org> wrote:
>> irq_start: needed because when the "interrupts" property is set for the
>> leaf component the irq number is irq_start +
>> object_property_get_int(obj, "irq[i]", NULL)
>> irq[i] being in [0, params->platform_bus_num_irqs]
>>
>> intc: this was in case the leaf component would use "interrupt-parent"
>> prop. I miss experience on device trees and I don't know if it make
>> sense the leaf component uses a different interrupt controller than the
>> parent platform bus or if such property is mandatory in some cases.
>> Maybe not needed indeed.
> 
> Somewhat tangential, but for passthrough devices how
> do we decide whether the device tree node needs to
> mark the interrupt as edge or level triggered?
> Presumably this is going to be a "depends on what
> the passed through hardware is" thing...

Hi Peter,

Yes I think this is one of the reasons why Alex insisted on having the
device node creation specialized for each device and not common to VFIO
devices.

Besides, I did not looked sufficiently at Antonios' patch "VFIO:
PLATFORM: Return device tree info for a platform device node" but I
guess this would enable to retrieve the property values.
https://www.mail-archive.com/kvm@vger.kernel.org/msg106282.html.

But I remember I read somewhere such interrupts properties were not
always correct in dt?

Best Regards

Eric
> 
> -- PMM
>