135 lines
3.0 KiB
C
135 lines
3.0 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Real Time Clock Periodic Interrupt test program
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*
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* Since commit 6610e0893b8bc ("RTC: Rework RTC code to use timerqueue for
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* events"), PIE are completely handled using hrtimers, without actually using
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* any underlying hardware RTC.
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*
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*/
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#include <stdio.h>
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#include <linux/rtc.h>
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#include <sys/ioctl.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <errno.h>
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/*
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* This expects the new RTC class driver framework, working with
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* clocks that will often not be clones of what the PC-AT had.
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* Use the command line to specify another RTC if you need one.
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*/
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static const char default_rtc[] = "/dev/rtc0";
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int main(int argc, char **argv)
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{
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int i, fd, retval, irqcount = 0;
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unsigned long tmp, data, old_pie_rate;
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const char *rtc = default_rtc;
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struct timeval start, end, diff;
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switch (argc) {
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case 2:
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rtc = argv[1];
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/* FALLTHROUGH */
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case 1:
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break;
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default:
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fprintf(stderr, "usage: rtctest [rtcdev] [d]\n");
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return 1;
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}
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fd = open(rtc, O_RDONLY);
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if (fd == -1) {
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perror(rtc);
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exit(errno);
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}
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/* Read periodic IRQ rate */
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retval = ioctl(fd, RTC_IRQP_READ, &old_pie_rate);
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if (retval == -1) {
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/* not all RTCs support periodic IRQs */
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if (errno == EINVAL) {
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fprintf(stderr, "\nNo periodic IRQ support\n");
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goto done;
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}
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perror("RTC_IRQP_READ ioctl");
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exit(errno);
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}
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fprintf(stderr, "\nPeriodic IRQ rate is %ldHz.\n", old_pie_rate);
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fprintf(stderr, "Counting 20 interrupts at:");
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fflush(stderr);
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/* The frequencies 128Hz, 256Hz, ... 8192Hz are only allowed for root. */
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for (tmp=2; tmp<=64; tmp*=2) {
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retval = ioctl(fd, RTC_IRQP_SET, tmp);
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if (retval == -1) {
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/* not all RTCs can change their periodic IRQ rate */
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if (errno == EINVAL) {
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fprintf(stderr,
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"\n...Periodic IRQ rate is fixed\n");
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goto done;
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}
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perror("RTC_IRQP_SET ioctl");
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exit(errno);
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}
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fprintf(stderr, "\n%ldHz:\t", tmp);
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fflush(stderr);
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/* Enable periodic interrupts */
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retval = ioctl(fd, RTC_PIE_ON, 0);
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if (retval == -1) {
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perror("RTC_PIE_ON ioctl");
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exit(errno);
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}
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for (i=1; i<21; i++) {
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gettimeofday(&start, NULL);
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/* This blocks */
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retval = read(fd, &data, sizeof(unsigned long));
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if (retval == -1) {
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perror("read");
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exit(errno);
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}
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gettimeofday(&end, NULL);
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timersub(&end, &start, &diff);
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if (diff.tv_sec > 0 ||
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diff.tv_usec > ((1000000L / tmp) * 1.10)) {
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fprintf(stderr, "\nPIE delta error: %ld.%06ld should be close to 0.%06ld\n",
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diff.tv_sec, diff.tv_usec,
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(1000000L / tmp));
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fflush(stdout);
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exit(-1);
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}
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fprintf(stderr, " %d",i);
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fflush(stderr);
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irqcount++;
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}
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/* Disable periodic interrupts */
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retval = ioctl(fd, RTC_PIE_OFF, 0);
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if (retval == -1) {
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perror("RTC_PIE_OFF ioctl");
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exit(errno);
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}
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}
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done:
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ioctl(fd, RTC_IRQP_SET, old_pie_rate);
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fprintf(stderr, "\n\n\t\t\t *** Test complete ***\n");
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close(fd);
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return 0;
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}
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