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Old 10-18-2012, 09:49 AM   #1
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ISR mapping, Kernel IRQ to Real Processor IRQ

ISR Mapping to a particular device through Linux Kernel?

For example:

I had request for a interrupt for some special device(i.e sysconfig interrupt as in OMAP L138), Let say i had requestd irq number 39 and consider i had also done handler function for that. My question here is whenever the sysconfig interrupt came, program counter will automatically jump to the -[sysconfig interrupt vector address] how far configuring irq line 39 can catch this interrupt and map the ISR of it to the sysconfig interrupt vector address.
Old 10-24-2012, 08:28 AM   #2
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On most systems, IRQ lines are shared. In any case, the interrupt architecture of various computer systems / motherboards is one of the biggest areas of difference that you will find. The kernel is designed, to some degree, to abstract-away a little bit of that nonsense, but it's still there.

You need either to know or to configure which hardware interrupt your device is going to throw, so that you can attach your first-level handler to the appropriate chain, then your handler must still poll the hardware to find out whether, in fact, your device is actually the one that's talking. (Think of it like the old telephone "party lines.")

Let the kernel do the dirty-work of passing control to your handler, since it might be a different mechanism for different hardware types. Also don't be concerned about precisely how your CPU-type deals with interruptions. Let the kernel give you the opportunity to respond, however it wants to do that.

Last edited by sundialsvcs; 10-24-2012 at 08:30 AM.


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