Re: switching to interrupt contex when no interrupts

[george anzinger <george@mvista.com>]

george anzinger wrote:
> 
> arun4linux wrote:
> >
> > Hello,
> >
> > <<One is forced to run in interrupt context in an
> > interrupt handler.
> > >>Yes. But my requirement is to force my code to run in interrupt context.
> >
> > <<Possibility is undefined here because what you said makes no sense.
> >
> > You will get a better answer from the list if you describe what you are trying to do (in concrete terms), not how you think you might do it.
> >
> > >>My requirement is to simulate a PCI based controller and its behaviour in software. I knew the different type of interrupts and the timings my device produces.
> >
> > I need to simulate this PCI device, its interrupts in sequence and I have to process them in my driver software.
> >
> >   Hope this make sense now.
> >
> >   Anyway, my requrirement is to simulate the interrupts and process them in the interrupt context.
> >
> >   It would be helpful, if anyone could help me how to do it.
> >   My idea is to use task queues and bottom halves for this. But I'd like to get clarified on simulating interrupts (rasing the process/task context to interrupt context) and its consequences.
> >
> Why simulate the interrupts when you can just program them?
> On the x86 machine the "int x" instruction generates an
> interrupt to irq "x"+32.  You do need to be in kernel land
> to do this, but then I assume that is not a problem.

Uh, make that "x"-32, i.e. "int 34" give irq 2.

-g
> 
> -g
> 
> >
> > Thanks & Warm Regards
> > Arun
> >
> > "John K Luebs" wrote:
> >
> > On Sat, Nov 23, 2002 at 07:37:33AM +0530, arun4linux wrote:
> > &gt; Hello,
> > &gt;
> > &gt; I'd like to force my kernel module to run at interrupt context at some specific points/time and then come back from interrrupt contex after executing that particular portion of code..
> >
> > You seem to be over complexifying what interrupt context is. It is
> > simply a generic term for a context that executes on account of an
> > architecture interrupt. One is forced to run in interrupt context in an
> > interrupt handler.
> >
> > You "run" in interrupt context by calling request_irq attached to the
> > interrupt line that you are interested in installing a handler for.
> >
> > &gt;
> > &gt; Is it possible?
> >
> > Possibility is undefined here because what you said makes no sense.
> >
> > You will get a better answer from the list if you describe what you are
> > trying to do (in concrete terms), not how you think you might do it.
> >
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> --
> George Anzinger   george@mvista.com
> High-res-timers:
> http://sourceforge.net/projects/high-res-timers/
> Preemption patch:
> http://www.kernel.org/pub/linux/kernel/people/rml
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-- 
George Anzinger   george@mvista.com
High-res-timers: 
http://sourceforge.net/projects/high-res-timers/
Preemption patch:
http://www.kernel.org/pub/linux/kernel/people/rml