interrupt handler on the Xilkernel PPC405

hallo, people,

I am a beginner on Xilkernel running on PPC405-Virtex 4.

I just want to get interrupt generated from the OPB peripheral and the
have the interrupt handler routine serviced. It seems there is a bug I
can not find. The Xilkernel has no interaction with the interrupt
handler routine. I have taken the example project from Xilinx website,
which generates a periodic interrupts from a timer. The piece of codes
is as following:


#include "xmk.h"
#include <os_config.h>
#include <stdio.h>
#include <xparameters.h>
#include <xtmrctr_l.h>
#include <xstatus.h>
#include <pthread.h>
#include <semaphore.h>
#include <sys/intr.h>

#define TIMER_COUNTER_ID        0

volatile unsigned int mins, hrs, secs, tot_secs = 0;
unsigned int addr=XPAR_TIMER_2_BASEADDR;

int_id_t intTimerID = XPAR_INTC_TIMER_2_INTERRUPT_INTR;

void interval_timer_initialize ()
{
    print ("CLOCK: Configuring extra timer to generate one interrupt
per second..\r\n");
    XTmrCtr_mWriteReg (addr, TIMER_COUNTER_ID,
                       XTC_TLR_OFFSET, SYSTMR_CLK_FREQ);

    // reset the timers, and clear interrupts
    XTmrCtr_mSetControlStatusReg (addr, TIMER_COUNTER_ID,
				  XTC_CSR_INT_OCCURED_MASK | XTC_CSR_LOAD_MASK );

    // start the timer
    XTmrCtr_mSetControlStatusReg (addr, 0,
                                  XTC_CSR_ENABLE_TMR_MASK |
XTC_CSR_ENABLE_INT_MASK |
                                  XTC_CSR_AUTO_RELOAD_MASK |
XTC_CSR_DOWN_COUNT_MASK );
}

void extra_timer_int_handler ()
{
    unsigned int control_reg;

    control_reg = XTimerCtr_mReadReg (addr, TIMER_COUNTER_ID,
XTC_TCSR_OFFSET);

  XTmrCtr_mWriteReg (addr, TIMER_COUNTER_ID,
                       XTC_TCSR_OFFSET,
                       XTC_CSR_LOAD_MASK | XTC_CSR_INT_OCCURED_MASK);

    // remove the reset condition such that the timer counter starts
running
    // with the value loaded from the compare register
    XTmrCtr_mWriteReg (addr, TIMER_COUNTER_ID,
                       XTC_TCSR_OFFSET,
                       control_reg | XTC_CSR_ENABLE_TMR_MASK);
}


void* my_main (void *arg)
{
    int a = 0;
    XStatus status;

    if ((status = register_int_handler(intTimerID,
extra_timer_int_handler, NULL)) != XST_SUCCESS) {
	xil_printf ("CLOCK: Unable to register handler. Error code: %d.\r\n",
status);
	goto err;

    }
    else print ("CLOCK: Successfully registered a handler for extra
timer interrupts.\r\n");

    interval_timer_initialize ();

    print ("CLOCK: Enabling the interval timer interrupt...\r\n");

   enable_interrupt (intTimerID);

    while (1) {

    }

 err:
    xil_printf ("CLOCK: Clock functions unavailable...\r\n");
    return NULL;
}

int main(){
	xil_printf("main\r\n");
	xilkernel_main();
	return 0;
}

I think the magic functions with Xilkernal are just the
"register_int_handler" and "enable_interrupt". I have initialized the
timer properly and read the control status register while running. The
timer generates the interrupt bit correctly but THE INTERRUPT HANDLER
JUST KEEPS SILENCE. I have checked everything I can. With Standalone,
the board just runs perfectly.

Could anyone give me a hint or help? I am blocked here for the simple
project for several days and quasi-mad.

Thanks in advance

zl