Edge Interrupts (Virtex-II Pro)

Edge Interrupts (Virtex-II Pro)

[Joshua Lamorie]

Gidday there,

Is there a cleaner way to specify that an interrupt is edge triggered 
other than directly accessing irq_desc_t irq_desc []?

In my module, when I request_irq, if it succeeds I do the following.

      irq_desc[iIRQ].status &= ~(IRQ_LEVEL);

Is there a better way?

Thanks in advance

Joshua

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Re: Edge Interrupts (Virtex-II Pro)

[Andrei Konovalov]

Joshua Lamorie wrote:
> Gidday there,
> 
> Is there a cleaner way to specify that an interrupt is edge triggered 
> other than directly accessing irq_desc_t irq_desc []?

In case of ML300 (which is the only Virtex-II Pro board in the linux-2.5
tree so far) this is done in platforms/xilinx_ml300.c:ml300_init_irq()
based on XPAR_INTC_0_KIND_OF_INTR value defined in the xparameters.h:

         for (i = 0; i < NR_IRQS; i++) {
                 if (XPAR_INTC_0_KIND_OF_INTR & (0x80000000 >> i))
                         irq_desc[i].status &= ~IRQ_LEVEL;
                 else
                         irq_desc[i].status |= IRQ_LEVEL;
         }

As this code is not board specific at all,
I would move it to arch/ppc/syslib/xilinx_pic.c:ppc4xx_pic_init().
Does it sound reasonable (I'll prepare the patch this weekend then)?

Hmm...
Looks like I've forgotten to change the irq numbering here...
Must be
   if (XPAR_INTC_0_KIND_OF_INTR & (0x00000001 << i))
I think...
Will check.

Thanks,
Andrei

P.S.
Just in case you use 2.4.
2.4 kernel is almost the same to 2.6 in this sense.
But the irq numbering is different.

> In my module, when I request_irq, if it succeeds I do the following.
> 
>      irq_desc[iIRQ].status &= ~(IRQ_LEVEL);
> 
> Is there a better way?
>
> Thanks in advance
> 
> Joshua
> 

Re: Edge Interrupts (Virtex-II Pro)

[Joshua Lamorie]

Andrei Konovalov wrote:

> As this code is not board specific at all,
> I would move it to arch/ppc/syslib/xilinx_pic.c:ppc4xx_pic_init().
> Does it sound reasonable (I'll prepare the patch this weekend then)?

This sounds useful, since I am using a custom developed board using the 
Virtex-II Pro. Unfortunately, the patch wouldn't help me much because I 
am doing my interrupt setup for most of my custom devices within 
modules. You see my hardware has a Virtex-II Pro and a Virtex-II with a 
shared (logically) address space (OPB). I have cascaded interrupt 
controllers (ask me if anyone wants the code). So it is quite often that 
I have a changed hardware and therefore require different drivers. 
Rather than downloading to flash the 700k kernel each time while I am 
developing, I just download the 6k - 20k modules. Then I store them in 
onboard NOR flash.

That's a long way of saying YES, isn't it?

Joshua

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