How to register an interrupt under linux?

Dear all,
First here is the setup i've:
1. The board is SPTWIMAX-CC1E board
2. The processor is MPC8555 i found it in the powerpc family NOT ppc family. Also the board contains DSP core.
3. Linux Kernel 2.6.19-rc5 running on the MPC8555 processor side.

I aim to let the DSP processor interrupts the MPC8555 processor so i think the first step is to register an interrupt handler for an interrupt number. i found this in the linux API request_irq. so

i make a simple module & write in it request_irq(4,my_handler,SA_INTERRUPT,"DSP",NULL); but unfortunately it returns -ENOSYS. i have tracked the error & i found this is because the irq_chip structure was not set.

so i added the API of set_irq_chip as follows:

irqChip.enable = NULL;
irqChip.disable = NULL;
irqChip.startup = NULL;
irqChip.shutdown = NULL;

so that all of these functions will be set to the default APIs (default_enable,default_disable,default_startup & default_shutdown)

then i passed this struct to the set_irq_chip as follows:

set_irq_chip(4,&irqChip);

& at last i call request_irq.
***********************************************************
My code:

irqChip.enable = NULL;
irqChip.disable = NULL;
irqChip.startup = NULL;
irqChip.shutdown = NULL;

set_irq_chip(4,&irqChip);

request_irq(4,my_handler,SA_INTERRUPT,"DSP",NULL);
********************************************************

but unfortunately when i tried to insert my module i got a segmentation
fault. i have tracked it & i found this is because of the unmask function of my interrupt irq_chip was not set.
so do i have to implement it & if so, should i write a code that enables my irq_number for the MPC8555 processor or what?

At last i want you to tell me if this is the right way to register my interrupt_handler for a certain interrupt_number under linux? this is my aim.
thanks in advance for your help

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That's rather old...

If we had a FAQ, this would be entry #1. request_irq() takes virtual IRQ numbers, not hardware numbers of some specific PIC. You need to create a mapping, typically via the device tree. Google should be able to provide more details.

That's kind of like commenting out every line with an error until the code builds. :-P

That tends to happen if you tell the kernel to call a NULL pointer.

i have tracked it & i found this is because of the unmask function of

No, it's already implemented in the MPIC driver.

-Scott