/*
 * mon_int.c: Monitor interrupts from FPGA
 *
  *  AUTHOR: 	Mark McDermott
 *  CREATED: 	June 12, 2008
 *  COPYRIGHT:	2008 The Learning Labs, Inc.
 *
 *  DESCRIPTION: This program opens up a char device and monitors interrupts
 *               coming from the FPGA through PF16 on the iMX21.
 *  DEPENDENCIES: none
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
 

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>

#define fpga_MAJOR 245

int det_int=0;
int num_int =0;

/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
*  This routine would do the interrupt handling for the main loop.
*
*/

void sighandler(int signo)
{
    if (signo==SIGIO)
        det_int++;
    printf("\nmon_interrupt: Interrupt captured by SIGIO\n");  // DEBUG
    return;  /* Return to main loop */

}

char buffer[4096];

int main(int argc, char **argv)
{
    int count;
    struct sigaction action;
    int fd;
    int rc;
    int fc;

//    memset(&action, 0, sizeof(action));
    sigemptyset(&action.sa_mask);
    sigaddset(&action.sa_mask, SIGIO);
    
    action.sa_handler = sighandler;
    action.sa_flags = 0;

    sigaction(SIGIO, &action, NULL);
    
    fd = open("/dev/fpga_int", O_RDWR);
    if (fd == -1) {
    	perror("Unable to open /dev/fpa_int");
    	rc = fd;
    	exit (-1);
    }
    
    printf("\nmon_interrupt: /dev/fpga_int opened successfully\n");    	

    fc = fcntl(fd, F_SETOWN, getpid());
    
    if (fc == -1) {
    	perror("SETOWN failed\n");
    	rc = fd;
    	exit (-1);
    } 

      
    fc= fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_ASYNC);

    if (fc == -1) {
    	perror("SETFL failed\n");
    	rc = fd;
    	exit (-1);
    }   

    
/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
*
*   This while loop emulates a program running the main
*   loop i.e. sleep(). The main loop is interrupted when
*   the SIGIO signal is received.
*/
    
    while(1) {
    
        /* this only returns if a signal arrives */
        sleep(86400); /* one day */
        if (!det_int)
            continue;
        num_int++;
        printf("mon_interrupt: Number of interrupts detected: %d\n", num_int);
        
        det_int=0;
    }
}