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1// SPDX-License-Identifier: GPL-2.02/*3 * Real Time Clock Periodic Interrupt test program4 *5 * Since commit 6610e0893b8bc ("RTC: Rework RTC code to use timerqueue for6 * events"), PIE are completely handled using hrtimers, without actually using7 * any underlying hardware RTC.8 *9 */10 11#include <stdio.h>12#include <linux/rtc.h>13#include <sys/ioctl.h>14#include <sys/time.h>15#include <sys/types.h>16#include <fcntl.h>17#include <unistd.h>18#include <stdlib.h>19#include <errno.h>20 21#include "../kselftest.h"22 23/*24 * This expects the new RTC class driver framework, working with25 * clocks that will often not be clones of what the PC-AT had.26 * Use the command line to specify another RTC if you need one.27 */28static const char default_rtc[] = "/dev/rtc0";29 30int main(int argc, char **argv)31{32 int i, fd, retval;33 unsigned long tmp, data, old_pie_rate;34 const char *rtc = default_rtc;35 struct timeval start, end, diff;36 37 switch (argc) {38 case 2:39 rtc = argv[1];40 break;41 case 1:42 fd = open(default_rtc, O_RDONLY);43 if (fd == -1) {44 printf("Default RTC %s does not exist. Test Skipped!\n", default_rtc);45 exit(KSFT_SKIP);46 }47 close(fd);48 break;49 default:50 fprintf(stderr, "usage: rtctest [rtcdev] [d]\n");51 return 1;52 }53 54 fd = open(rtc, O_RDONLY);55 56 if (fd == -1) {57 perror(rtc);58 exit(errno);59 }60 61 /* Read periodic IRQ rate */62 retval = ioctl(fd, RTC_IRQP_READ, &old_pie_rate);63 if (retval == -1) {64 /* not all RTCs support periodic IRQs */65 if (errno == EINVAL) {66 fprintf(stderr, "\nNo periodic IRQ support\n");67 goto done;68 }69 perror("RTC_IRQP_READ ioctl");70 exit(errno);71 }72 fprintf(stderr, "\nPeriodic IRQ rate is %ldHz.\n", old_pie_rate);73 74 fprintf(stderr, "Counting 20 interrupts at:");75 fflush(stderr);76 77 /* The frequencies 128Hz, 256Hz, ... 8192Hz are only allowed for root. */78 for (tmp=2; tmp<=64; tmp*=2) {79 80 retval = ioctl(fd, RTC_IRQP_SET, tmp);81 if (retval == -1) {82 /* not all RTCs can change their periodic IRQ rate */83 if (errno == EINVAL) {84 fprintf(stderr,85 "\n...Periodic IRQ rate is fixed\n");86 goto done;87 }88 perror("RTC_IRQP_SET ioctl");89 exit(errno);90 }91 92 fprintf(stderr, "\n%ldHz:\t", tmp);93 fflush(stderr);94 95 /* Enable periodic interrupts */96 retval = ioctl(fd, RTC_PIE_ON, 0);97 if (retval == -1) {98 perror("RTC_PIE_ON ioctl");99 exit(errno);100 }101 102 for (i=1; i<21; i++) {103 gettimeofday(&start, NULL);104 /* This blocks */105 retval = read(fd, &data, sizeof(unsigned long));106 if (retval == -1) {107 perror("read");108 exit(errno);109 }110 gettimeofday(&end, NULL);111 timersub(&end, &start, &diff);112 if (diff.tv_sec > 0 ||113 diff.tv_usec > ((1000000L / tmp) * 1.10)) {114 fprintf(stderr, "\nPIE delta error: %ld.%06ld should be close to 0.%06ld\n",115 diff.tv_sec, diff.tv_usec,116 (1000000L / tmp));117 fflush(stdout);118 exit(-1);119 }120 121 fprintf(stderr, " %d",i);122 fflush(stderr);123 }124 125 /* Disable periodic interrupts */126 retval = ioctl(fd, RTC_PIE_OFF, 0);127 if (retval == -1) {128 perror("RTC_PIE_OFF ioctl");129 exit(errno);130 }131 }132 133done:134 ioctl(fd, RTC_IRQP_SET, old_pie_rate);135 136 fprintf(stderr, "\n\n\t\t\t *** Test complete ***\n");137 138 close(fd);139 140 return 0;141}142