Finding the interrupt vector of a given IRQ

[Arun KS]

Hi Anish,

On Mon, May 28, 2012 at 9:16 AM, anish singh <anish198519851985 at gmail.com>wrote:

> On Mon, May 28, 2012 at 2:57 AM, richard -rw- weinberger
> <richard.weinberger at gmail.com> wrote:
> > On Sun, May 27, 2012 at 2:02 AM, Mark Farnell <mark.farnell at gmail.com>
> wrote:
> >> In the kernel, how can I find out the interrupt vector number of a
> >> given IRQ (for example, IRQ7)?
> >>
> >> Within the kernel module, I would like to manually set the IRQ using
> >> the assembly code:
> >>
> >> asm("int $<irq vector>");
> >>
> >> and let the IRQ handler installed by a different module catch that
> interrupt.
> >>
> >> Is this possible?
> >
> > No really because not all IRQ have an interrupt line to the CPU.
> > Linux can multiplex and emulate them. Think of GPIO drivers with
> > interrupt support.
> Can you please describe this in detail?It would really help a lot of
> people like me.Does multiplex mean that all numbers starting from
> 0,1,2,3,...... TOTAL-interrupt will have interrupt lines associated with it
> eventhough all interrupt numbers are not linear?
>

GPIOs are grouped as banks. Let’s say 32 gpios are in a bank.
There will be only single interrupt line to interrupt controller for a bank.


Consider that you have configured gpio1 and gpio16 as interrupts.
Even if interrupt happens on gpio 1 or gpio 16, the same interrupt line
will be triggered to

Interrupt controller.


Now the gpio driver has to figure out reading the Interrupt status

Register of GPIO to find which interrupt (gpio1 or gpio16) has really fired.

So in this case a single interrupt line is multiplex for 32 gpio interrupts.

HTH.

Thanks,
Arun


> > Anyway, why to you think you need to trigger the raw IRQ manually?
> > This sounds really odd...
> >
> >
> > --
> > Thanks,
> > //richard
> >
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