IRQ handler is not called with external IRQ

Ran Shalit ranshalit at
Mon Aug 17 15:24:09 AEST 2015


I have strange behaviour with external IRQ:
The registration on external IRQ is successful, but on simulating
interrupt the interrupt handler called.
It seems that the interrupt was received according to SEPNR which
shows that IRQ #2 interrupt is pending, but the handler was not

These are the steps I done:

1. in DTS (using all external IRQ #2):

  intc2 at 0{
  compatible = "intc2";
   #address-cells = <1>;
   #size-cells = <0>;
   reg = <0 0x1000>;
   interrupts = <2 0x8> ;
   interrupt-parent = <&ipic>;

2. registration in kernel for all interrupts:

  np = of_find_node_by_name(NULL,"intc2");
  if (np == NULL)
      printk("Error node not found\n");
     printk("Node np = 0x%0x\n",np);
     virq = irq_of_parse_and_map(np,0);
     printk(KERN_INFO"IRQHandler: ISR Setup VIRQ: %d \n" , virq);
     if (0 > (error=request_irq(virq, &IRQHandler, 0, "intc2", &value))) {
     printk(KERN_WARNING"IRQHandler: Init: Unable to allocate IRQ
error = %d\n\n", error);
     return -1;

3. interrupt handler code:

int newval = 0;
static irqreturn_t hello_IRQHandler(int irq, void *dev_id)
         unsigned int status;
         struct timespec curr_tm;
         return IRQ_HANDLED;

4. in boot I get print which show success with request_irq():

Node np = 0xdfffe288
IRQHandler: ISR Setup VIRQ: 22
NET: Registered protocol family 17

5. forcing interrupt in IRQ #2, or #4 result in SEPNR change, but
there is no printing from interrupt handler

6. validation in SEPNR register that interrupt was received:

# devmem2 0xe000072c
/dev/mem opened.
Memory mapped at address 0xb7b80000.
Value at address 0xE000072C (0xb7b8072c): 0x20000000

Thank you for any suggestion,


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