/**********************************************************************
* Linux RTC Test Example rtctest.c hacking
* 说明：
* 之前的Linux版本都没有这种针对硬件的测试代码示例，比较新的内核里
* 好像对了这些内核测试用例。
*
* 2017-8-15 深圳 龙华樟坑村 曾剑锋
*********************************************************************/
// 参考文档：
// 1. https://github.com/torvalds/linux/tree/master/tools/testing/selftests
// 2. Real Time Clock (RTC) Drivers for Linux
// https://android.googlesource.com/kernel/common/+/android-4.4/Documentation/rtc.txt
/*
* 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 <stdlib.h>
#include <errno.h>
#ifndef ARRAY_SIZE
# define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[]))
#endif
/*
* This expects the new RTC class driver framework, working with
* clocks that will often not be clones of what the PC-AT had.
* Use the command line to specify another RTC if you need one.
*/
// 默认rtc设备节点
static const char default_rtc[] = "/dev/rtc0";
// 后面用于设置rtc时间，获取rtc时间，然后对比设置、获取的时间来判断是否正确
static struct rtc_time cutoff_dates[] = {
{
.tm_year = , /* 1970 -1900 */
.tm_mday = ,
},
/* signed time_t 19/01/2038 3:14:08 */
{
.tm_year = ,
.tm_mday = ,
},
{
.tm_year = ,
.tm_mday = ,
},
{
.tm_year = , /* 2099 -1900 */
.tm_mday = ,
},
{
.tm_year = , /* 2100 -1900 */
.tm_mday = ,
},
/* unsigned time_t 07/02/2106 7:28:15*/
{
.tm_year = ,
.tm_mon = ,
.tm_mday = ,
},
{
.tm_year = ,
.tm_mon = ,
.tm_mday = ,
},
/* signed time on 64bit in nanoseconds 12/04/2262 01:47:16*/
{
.tm_year = ,
.tm_mon = ,
.tm_mday = ,
},
{
.tm_year = , /* 2262 -1900 */
.tm_mon = ,
.tm_mday = ,
},
};
// 时间对比函数
static int compare_dates(struct rtc_time *a, struct rtc_time *b)
{
if (a->tm_year != b->tm_year ||
a->tm_mon != b->tm_mon ||
a->tm_mday != b->tm_mday ||
a->tm_hour != b->tm_hour ||
a->tm_min != b->tm_min ||
((b->tm_sec - a->tm_sec) > ))
return ;
return ;
}
int main(int argc, char **argv)
{
int i, fd, retval, irqcount = , dangerous = ;
unsigned long tmp, data;
struct rtc_time rtc_tm;
const char *rtc = default_rtc;
struct timeval start, end, diff;
// 这里的倒序的case可以借鉴
switch (argc) {
case :
if (*argv[] == 'd')
dangerous = ; // 没搞懂这里为什么叫dangerous
case :
rtc = argv[]; // rtc设备节点
/* FALLTHROUGH */
case :
break;
default:
fprintf(stderr, "usage: rtctest [rtcdev] [d]\n");
return ;
}
fd = open(rtc, O_RDONLY);
if (fd == -) {
perror(rtc);
exit(errno);
}
fprintf(stderr, "\n\t\t\tRTC Driver Test Example.\n\n");
/* Turn on update interrupts (one per second) */
// 这里算是自动时间更新中断，有些芯片可能不支持的，我现在使用的就不支持
retval = ioctl(fd, RTC_UIE_ON, );
if (retval == -) {
if (errno == EINVAL) {
fprintf(stderr,
"\n...Update IRQs not supported.\n");
goto test_READ;
}
perror("RTC_UIE_ON ioctl");
exit(errno);
}
// 直接读取
fprintf(stderr, "Counting 5 update (1/sec) interrupts from reading %s:",
rtc);
fflush(stderr);
for (i=; i<; i++) {
/* This read will block */
retval = read(fd, &data, sizeof(unsigned long));
if (retval == -) {
perror("read");
exit(errno);
}
fprintf(stderr, " %d",i);
fflush(stderr);
irqcount++;
}
// select读取
fprintf(stderr, "\nAgain, from using select(2) on /dev/rtc:");
fflush(stderr);
for (i=; i<; i++) {
struct timeval tv = {, }; /* 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+, &readfds, NULL, NULL, &tv);
if (retval == -) {
perror("select");
exit(errno);
}
/* This read won't block unlike the select-less case above. */
retval = read(fd, &data, sizeof(unsigned long));
if (retval == -) {
perror("read");
exit(errno);
}
fprintf(stderr, " %d",i);
fflush(stderr);
irqcount++;
}
/* Turn off update interrupts */
retval = ioctl(fd, RTC_UIE_OFF, );
if (retval == -) {
perror("RTC_UIE_OFF ioctl");
exit(errno);
}
test_READ:
/* Read the RTC time/date */
// 读取RTC时间
retval = ioctl(fd, RTC_RD_TIME, &rtc_tm);
if (retval == -) {
perror("RTC_RD_TIME 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 + , rtc_tm.tm_year + ,
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 += ;
if (rtc_tm.tm_sec >= ) {
rtc_tm.tm_sec %= ;
rtc_tm.tm_min++;
}
if (rtc_tm.tm_min == ) {
rtc_tm.tm_min = ;
rtc_tm.tm_hour++;
}
if (rtc_tm.tm_hour == )
rtc_tm.tm_hour = ;
// 设置闹钟
retval = ioctl(fd, RTC_ALM_SET, &rtc_tm);
if (retval == -) {
if (errno == EINVAL) {
fprintf(stderr,
"\n...Alarm IRQs not supported.\n");
goto test_PIE;
}
perror("RTC_ALM_SET ioctl");
exit(errno);
}
/* Read the current alarm settings */
retval = ioctl(fd, RTC_ALM_READ, &rtc_tm);
if (retval == -) {
perror("RTC_ALM_READ 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, );
if (retval == -) {
if (errno == EINVAL) {
fprintf(stderr,
"\n...Alarm IRQs not supported.\n");
goto test_PIE;
}
perror("RTC_AIE_ON 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 == -) {
perror("read");
exit(errno);
}
irqcount++;
fprintf(stderr, " okay. Alarm rang.\n");
/* Disable alarm interrupts */
retval = ioctl(fd, RTC_AIE_OFF, );
if (retval == -) {
perror("RTC_AIE_OFF ioctl");
exit(errno);
}
test_PIE:
/* Read periodic IRQ rate */
retval = ioctl(fd, RTC_IRQP_READ, &tmp);
if (retval == -) {
/* not all RTCs support periodic IRQs */
if (errno == EINVAL) {
fprintf(stderr, "\nNo periodic IRQ support\n");
goto test_DATE;
}
perror("RTC_IRQP_READ ioctl");
exit(errno);
}
fprintf(stderr, "\nPeriodic IRQ rate is %ldHz.\n", tmp);
fprintf(stderr, "Counting 20 interrupts at:");
fflush(stderr);
/* The frequencies 128Hz, 256Hz, ... 8192Hz are only allowed for root. */
for (tmp=; tmp<=; tmp*=) {
retval = ioctl(fd, RTC_IRQP_SET, tmp);
if (retval == -) {
/* not all RTCs can change their periodic IRQ rate */
if (errno == EINVAL) {
fprintf(stderr,
"\n...Periodic IRQ rate is fixed\n");
goto test_DATE;
}
perror("RTC_IRQP_SET ioctl");
exit(errno);
}
fprintf(stderr, "\n%ldHz:\t", tmp);
fflush(stderr);
/* Enable periodic interrupts */
retval = ioctl(fd, RTC_PIE_ON, );
if (retval == -) {
perror("RTC_PIE_ON ioctl");
exit(errno);
}
for (i=; i<; i++) {
gettimeofday(&start, NULL);
/* This blocks */
retval = read(fd, &data, sizeof(unsigned long));
if (retval == -) {
perror("read");
exit(errno);
}
gettimeofday(&end, NULL);
timersub(&end, &start, &diff);
if (diff.tv_sec > ||
diff.tv_usec > ((1000000L / tmp) * 1.10)) {
fprintf(stderr, "\nPIE delta error: %ld.%06ld should be close to 0.%06ld\n",
diff.tv_sec, diff.tv_usec,
(1000000L / tmp));
fflush(stdout);
exit(-);
}
fprintf(stderr, " %d",i);
fflush(stderr);
irqcount++;
}
/* Disable periodic interrupts */
retval = ioctl(fd, RTC_PIE_OFF, );
if (retval == -) {
perror("RTC_PIE_OFF ioctl");
exit(errno);
}
}
test_DATE:
if (!dangerous)
goto done;
fprintf(stderr, "\nTesting problematic dates\n");
for (i = ; i < ARRAY_SIZE(cutoff_dates); i++) {
struct rtc_time current;
/* Write the new date in RTC */
// 设置RTC时间
retval = ioctl(fd, RTC_SET_TIME, &cutoff_dates[i]);
if (retval == -) {
perror("RTC_SET_TIME ioctl");
close(fd);
exit(errno);
}
/* Read back */
// 读取RTC时间
retval = ioctl(fd, RTC_RD_TIME, ¤t);
if (retval == -) {
perror("RTC_RD_TIME ioctl");
exit(errno);
}
// 对比RTC时间
if(compare_dates(&cutoff_dates[i], ¤t)) {
fprintf(stderr,"Setting date %d failed\n",
cutoff_dates[i].tm_year + );
goto done;
}
cutoff_dates[i].tm_sec += ;
/* Write the new alarm in RTC */
// 设置闹钟时间
retval = ioctl(fd, RTC_ALM_SET, &cutoff_dates[i]);
if (retval == -) {
perror("RTC_ALM_SET ioctl");
close(fd);
exit(errno);
}
/* Read back */
// 读取闹钟时间
retval = ioctl(fd, RTC_ALM_READ, ¤t);
if (retval == -) {
perror("RTC_ALM_READ ioctl");
exit(errno);
}
// 对比闹钟时间
if(compare_dates(&cutoff_dates[i], ¤t)) {
fprintf(stderr,"Setting alarm %d failed\n",
cutoff_dates[i].tm_year + );
goto done;
}
fprintf(stderr, "Setting year %d is OK \n",
cutoff_dates[i].tm_year + );
}
done:
fprintf(stderr, "\n\n\t\t\t *** Test complete ***\n");
close(fd);
return ;
}