How kernel handle interrupts

[narkewoody@gmail.com (Woody Wu)]

On Thu, Dec 20, 2012 at 10:05:05AM -0800, anish singh wrote:
> On Dec 20, 2012 6:30 AM, "Woody Wu" <narkewoody@gmail.com> wrote:
> >
> > Hi, List
> >
> > Where is the Kernel code that handles external interrupts? I want to
> > have a look at it but haven't found out where it is.
> >
> > Actually, I have some basic questions about interrupt handling in Linux.
> > 1. After Kernel's ISR received an interrupt, I believe it will invoke a
> >    handler defined in a device driver if any. But it should be the
> >    device driver's responsibility or kernel ISR's responsibility to
> >    clear (or acknowledge) the interrupt?
> If the interrupt in question is currently being handled then in
> the case of edge triggered interrupt we just mask the interrupt,set it
> pending and bail out.Once the interrupt handler completes then we check for
> pending interrupt and handle it.In level triggered we don't do that.
> Kerenel ISR -this is mixture of core kernel interrupt handling code + your
> device driver interrupt handler(if this is chip driver which is supposed to
> get one interrupt and is reponsible for calling other interrupt handlers
> based on the chip register status then you do explicit masking unmasking
> yourself).
> If you device driver is a interrupt controller driver then you register
> your driver with kernel interrupt handling code and need to write some
> callbacks such as .mask,.unmask and so on.This callbacks are called at
> appropiate places whenever the interrupt is raised.This interrupt is then
> passed to drivers who has requested for this interrupt by calling
> request_irq.
> >
> > 2. My device, an AX88796B network controller, asserting the interrupt
> >    line in a level-triggered manner. Now I met problem with the device
> that
> >    might caused by the CPU interrupt mode is not set as level-triggered by
> >    edge trigger.  My CPU is Samsung S3C2410, an ARM920T powered one.  Does
> >    anyone know usually where and how should I do this kind of setting?
> Just pass the parameter "level triggered" in request_irq in your device
> driver.

Hi Sign,

I searched the interrupt.h for the all the defined flags that I can pass
to the request_irq, but there is no a flag looks like "level triggered".
Would you tell me what you mean the parameter "level triggered"?

Thanks.

> >
> >
> > Thanks in advance.
> >
> > --
> > woody
> > I can't go back to yesterday - because I was a different person then.
> >
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-- 
woody
I can't go back to yesterday - because I was a different person then.