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RTC interrupts.



Hi all;

   We are having some trouble porting an example to the AXIS system. The 
included code executes correctly on a PC, but gives an error on ETRAX. It 
compiles correctly on ETRAX, though. It seems we are doing something silly.

The code is from RTC.TXT
http://www.linuxhq.com/kernel/v2.4/doc/rtc.txt.html


/*
  *      Real Time Clock Driver Test/Example Program
  *
  *      Compile with:
  *              gcc -s -Wall -Wstrict-prototypes rtctest.c -o rtctest
  *
  *      Copyright (C) 1996, Paul Gortmaker.
  *
  *      Released under the GNU General Public License, version 2,
  *      included herein by reference.
  *
  */

#include <stdio.h>
#include <linux/rtc.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

void main(void) {

int i, fd, retval, irqcount = 0;
unsigned long tmp, data;
struct rtc_time rtc_tm;

fd = open ("/dev/rtc", O_RDONLY);

if (fd ==  -1) {
         perror("/dev/rtc");
         exit(errno);
}

fprintf(stderr, "\n\t\t\tRTC Driver Test Example.\n\n");

/* Turn on update interrupts (one per second) */
retval = ioctl(fd, RTC_UIE_ON, 0);
if (retval == -1) {
         perror("ioctl");
         exit(errno);
}

fprintf(stderr, "Counting 5 update (1/sec) interrupts from reading /dev/rtc:");
fflush(stderr);
for (i=1; i<6; i++) {
         /* This read will block */
         retval = read(fd, &data, sizeof(unsigned long));
         if (retval == -1) {
                 perror("read");
                 exit(errno);
         }
         fprintf(stderr, " %d",i);
         fflush(stderr);
         irqcount++;
}

fprintf(stderr, "\nAgain, from using select(2) on /dev/rtc:");
fflush(stderr);
for (i=1; i<6; i++) {
         struct timeval tv = {5, 0};     /* 5 second timeout on select */
         fd_set readfds;

         FD_ZERO(&readfds);
         FD_SET(fd, &readfds);
         /* The select will wait until an RTC interrupt happens. */
         retval = select(fd+1, &readfds, NULL, NULL, &tv);
         if (retval == -1) {
                 perror("select");
                 exit(errno);
         }
         /* This read won't block unlike the select-less case above. */
         retval = read(fd, &data, sizeof(unsigned long));
         if (retval == -1) {
                 perror("read");
                 exit(errno);
         }
         fprintf(stderr, " %d",i);
         fflush(stderr);
         irqcount++;
}

/* Turn off update interrupts */
retval = ioctl(fd, RTC_UIE_OFF, 0);
if (retval == -1) {
         perror("ioctl");
         exit(errno);
}

/* Read the RTC time/date */
retval = ioctl(fd, RTC_RD_TIME, &rtc_tm);
if (retval == -1) {
         perror("ioctl");
         exit(errno);
}

fprintf(stderr, "\n\nCurrent RTC date/time is %d-%d-%d, %02d:%02d:%02d.\n",
         rtc_tm.tm_mday, rtc_tm.tm_mon + 1, rtc_tm.tm_year + 1900,
         rtc_tm.tm_hour, rtc_tm.tm_min, rtc_tm.tm_sec);

/* Set the alarm to 5 sec in the future, and check for rollover */
rtc_tm.tm_sec += 5;
if (rtc_tm.tm_sec >= 60) {
         rtc_tm.tm_sec %= 60;
         rtc_tm.tm_min++;
}
if  (rtc_tm.tm_min == 60) {
         rtc_tm.tm_min = 0;
         rtc_tm.tm_hour++;
}
if  (rtc_tm.tm_hour == 24)
         rtc_tm.tm_hour = 0;

retval = ioctl(fd, RTC_ALM_SET, &rtc_tm);
if (retval == -1) {
         perror("ioctl");
         exit(errno);
}

/* Read the current alarm settings */
retval = ioctl(fd, RTC_ALM_READ, &rtc_tm);
if (retval == -1) {
         perror("ioctl");
         exit(errno);
}

fprintf(stderr, "Alarm time now set to %02d:%02d:%02d.\n",
         rtc_tm.tm_hour, rtc_tm.tm_min, rtc_tm.tm_sec);

/* Enable alarm interrupts */
retval = ioctl(fd, RTC_AIE_ON, 0);
if (retval == -1) {
         perror("ioctl");
         exit(errno);
}

fprintf(stderr, "Waiting 5 seconds for alarm...");
fflush(stderr);
/* This blocks until the alarm ring causes an interrupt */
retval = read(fd, &data, sizeof(unsigned long));
if (retval == -1) {
         perror("read");
         exit(errno);
}
irqcount++;
fprintf(stderr, " okay. Alarm rang.\n");

/* Disable alarm interrupts */
retval = ioctl(fd, RTC_AIE_OFF, 0);
if (retval == -1) {
         perror("ioctl");
         exit(errno);
}

/* Read periodic IRQ rate */
retval = ioctl(fd, RTC_IRQP_READ, &tmp);
if (retval == -1) {
         perror("ioctl");
         exit(errno);
}
fprintf(stderr, "\nPeriodic IRQ rate was %ldHz.\n", tmp);

fprintf(stderr, "Counting 20 interrupts at:");
fflush(stderr);

/* The frequencies 128Hz, 256Hz, ... 8192Hz are only allowed for root. */
for (tmp=2; tmp<=64; tmp*=2) {

         retval = ioctl(fd, RTC_IRQP_SET, tmp);
         if (retval == -1) {
                 perror("ioctl");
                 exit(errno);
         }

         fprintf(stderr, "\n%ldHz:\t", tmp);
         fflush(stderr);

         /* Enable periodic interrupts */
         retval = ioctl(fd, RTC_PIE_ON, 0);
         if (retval == -1) {
                 perror("ioctl");
                 exit(errno);
         }

         for (i=1; i<21; i++) {
                 /* This blocks */
                 retval = read(fd, &data, sizeof(unsigned long));
                 if (retval == -1) {
                         perror("read");
                         exit(errno);
                 }
                 fprintf(stderr, " %d",i);
                 fflush(stderr);
                 irqcount++;
         }

         /* Disable periodic interrupts */
         retval = ioctl(fd, RTC_PIE_OFF, 0);
         if (retval == -1) {
                 perror("ioctl");
                 exit(errno);
         }
}

fprintf(stderr, "\n\n\t\t\t *** Test complete ***\n");
fprintf(stderr, "\nTyping \"cat /proc/interrupts\" will show %d more events 
on IRQ 8.\n\n",
                                                                  irqcount);

close(fd);

} /* end main */








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