Re: [Qemu-devel] smc91x irq patch

[Fabrice Bellard]

Paul Brook wrote:
> On Tuesday 18 July 2006 18:03, Thorsten Zitterell wrote:
>
> > I am working on a Gumstix system [1] emulation for QEMU which is based
> > on a Intel XScale processor. The board has an expansion card for network
> > support which is a smc91x compatible NIC. However, the irq line is not
> > directly connected to the processor's interrupt controller but to an
> > GPIO which triggers an irq when a level edge is detected.
>
>
> As discussed on IRC this is the wrong way to do this. Instead use the 
> mechanisms in arm_pic.[ch] and make you GPIO emulation look like an interrupt 
> controller.
>
> There's no point passing round both a pic callback and an object when we can 
> embed the callback in the object.

I don't think that adding a callback is bad. It can be useful to use the 
device with another CPU or IRQ controller for example.

In fact, I would like to go further by adding a type such as 
"QEMUSignal" which could be used for IRQs or any other I/Os. Then you 
can pass it to devices. You can used qemu_signal_set(QEMUSignal *signal, 
int level) to set the level and add listeners to get notified on the 
changes with something like: qemu_add_signal_cb(QEMUSignal *signal, void 
(*cb)(void *opaque), void *opaque).

Regards,

Fabrice.