mjhjmtu

I have a pulse generator that's supposed to trigger my linux device to take an action, and that pulse goes to an IRQ on my processor.

In the linux device tree the interrupt is represented under this entry

align_trigger 
 compatible = "align_trigger";
 interrupt-parent = <0x1>;
 interrupts = <0x0 0x37 0x4>;
;

So in my kernel module I use this

dtnode = of_find_compatible_node(NULL,NULL,"align_trigger");
if(!dtnode)
 printk(KERN_ALERT "Unable to locate devicetree entryn");
else
 irq_index = of_irq_get(dtnode,0);
 if(irq_index>0)
 i = request_irq(irq_index,align_trigger_irq,0,"gxq_03",NULL);
 if(i)
 printk(KERN_ALERT "Unable to register IRQn");
 else
 printk(KERN_ALERT "Registed IRQ %dn",irq_index);
 
 

And then the IRQ handler I use is this

irqreturn_t align_trigger_irq(int irq,void *ptr, struct pt_regs *regs)
if(max_segment>0)
 if(current_segment>=max_segment)
 current_segment = 0;
 else
 current_segment++;
 
 printk(KERN_ALERT "CURRENT SEGMENT: %dn",current_segment);

return IRQ_HANDLED;

So at the moment its not doing much, just reporting when it gets triggered so I can confirm it. The pulse generator is sending interrupts in every 100 us, and I set the max segment to 100.

I checked my log every 10 seconds for 1 minute.

10 Seconds-> CURRENT FRAME: 1

20 Seconds-> CURRENT FRAME: 1

30 Seconds-> CURRENT FRAME: 2

40 Seconds-> CURRENT FRAME: 4

50 Seconds-> CURRENT FRAME: 5

60 Seconds-> CURRENT FRAME: 5

So I am certainly not getting the number of interrupts per second that I ought to be getting, and it doesn't really seem to be a consistent rate being seen by the processor.

The reported IRQ number was 165, so I looked at /proc/interrupts, since that's what's been mentioned on other posts about interrupts. The entry for 165 is this:

 CPU0 CPU1 
165: 8 0 GIC-0 87 Level gxq_03

The only thing I am able to verify is that my pulse generator is putting out pulses at the right rate, but there is alot that could potentially be going wrong in between that and my kernel module registering an interrupt. How can I proceed with debugging what is going wrong?