[rtl] interrupt handler

[Surya P Kommareddy]

Hi all,
        Merry Christmas and a happy new year. 
        I have been trying to write an Interrupt handler, for the parallel
port. Attached are the files for the module. Even though I don't give any
interrupt signal(tenth pin of the port) on the parallel port, the
interrupt handler gets activated. Am I doing something wrong?? I am using
RTlinux2.0 on Redhat6.1 with 2.2.13 kernel.

Thanks in anticipation,
Surya.



#define LPT_PORT 0x3bc
#define LPT_IRQ 7
#define RTC_IRQ 8

#include <rtl_time.h>
/*
struct sample {
        hrtime_t min;
        hrtime_t max;
};
*/

/*
 * RTL interrupt scheduling accuracy measuring example
 *
 * (C) Michael Barabanov, 1997
 * (C) FSMLabs  1999. [EMAIL PROTECTED]
 *  Released under the GNU GENERAL PUBLIC LICENSE Version 2, June 1991
 *  Any use of this code must include this notice.
 */
#include <rtl.h>
#include <rtl_fifo.h>
#include <rtl_core.h>
#include <time.h>
#include <asm/io.h>
#include <rtl_sched.h>
#include <rtl_sync.h>
#include <pthread.h>
#include <unistd.h>
#include <rtl_debug.h>
#include <errno.h>
#include "common.h"

int fd_fifo;
int output;
struct sample mysample;
int fifo_size=6000;
clockid_t myclock;

unsigned int intr_handler (unsigned int irq, struct pt_regs *regs)
{
        if(output==1) output=0;
        else output=1;
        outb(output, LPT_PORT);
        mysample.mytime=clock_gethrtime(myclock);
        mysample.mydata=output;
        write(fd_fifo, &mysample, sizeof(mysample));
        rtl_hard_enable_irq(irq);
        return 0;
}

int init_module(void)
{
        int rtl_status;
        int fifo_status;

        rtf_destroy(0);
        fifo_status = rtf_create(0, fifo_size);
        if (fifo_status) {
                rtl_printf("RTL measurement test fail. fifo_status=%d\n",fifo_status);
                return -1;
        }
        myclock= rtl_getschedclock();
        rtl_printf("The clock is %d\n", myclock);

        rtl_status= rtl_request_irq(LPT_IRQ, intr_handler);
        if(rtl_status == EBUSY)
        rtl_printf(" Interrupt handler is already installed for this interrupt\n");
        else if (rtl_status == EINVAL)
        rtl_printf(" There is no handler curently installed for this interrupt 
level\n");
 
        printk("I am starting the module\n");
        fd_fifo = open("/dev/rtf0", O_NONBLOCK);
        if (fd_fifo < 0) {
                rtl_printf("/dev/rtf0 open returned %d\n", fd_fifo);
                return (void *) -1;
        }
        rtl_hard_enable_irq(LPT_IRQ);
        outb(inb(LPT_CONTROL) | 0x10, LPT_CONTROL);
        return 0;
}

void cleanup_module(void)
{
        rtl_printf ("Removing module on CPU %d\n", rtl_getcpuid());
        rtl_free_irq(LPT_IRQ);
        close(fd_fifo);
        rtf_destroy(0);
}