/*
* Same as synchronize_to_clock_tick(), but just for /dev/rtc.
*/
static int synchronize_to_clock_tick_rtc(const struct hwclock_control *ctl)
{
int rtc_fd; /* File descriptor of /dev/rtc */
int ret = 1;
rtc_fd = open_rtc(ctl);
if (rtc_fd == -1) {
warn(_("cannot open rtc device"));
return ret;
} else {
/* Turn on update interrupts (one per second) */
int rc = ioctl(rtc_fd, RTC_UIE_ON, 0);
if (rc != -1) {
/*
* Just reading rtc_fd fails on broken hardware: no
* update interrupt comes and a bootscript with a
* hwclock call hangs
*/
fd_set rfds;
struct timeval tv;
/*
* Wait up to ten seconds for the next update
* interrupt
*/
FD_ZERO(&rfds);
FD_SET(rtc_fd, &rfds);
tv.tv_sec = 10;
tv.tv_usec = 0;
rc = select(rtc_fd + 1, &rfds, NULL, NULL, &tv);
if (0 < rc)
ret = 0;
else if (rc == 0) {
warnx(_("select() to %s to wait for clock tick timed out"),
rtc_dev_name);
} else
warn(_("select() to %s to wait for clock tick failed"),
rtc_dev_name);
/* Turn off update interrupts */
rc = ioctl(rtc_fd, RTC_UIE_OFF, 0);
if (rc == -1)
warn(_("ioctl() to %s to turn off update interrupts failed"),
rtc_dev_name);
} else if (errno == ENOTTY || errno == EINVAL) {
/* rtc ioctl interrupts are unimplemented */
ret = busywait_for_rtc_clock_tick(ctl, rtc_fd);
} else
warn(_("ioctl(%d, RTC_UIE_ON, 0) to %s failed"),
rtc_fd, rtc_dev_name);
}
return ret;
}
/*
* Same as synchronize_to_clock_tick(), but just for /dev/rtc.
*/
static int synchronize_to_clock_tick_rtc(void)
{
int rtc_fd; /* File descriptor of /dev/rtc */
int ret;
rtc_fd = open_rtc();
if (rtc_fd == -1) {
warn(_("cannot open %s"), rtc_dev_name);
ret = 1;
} else {
int rc; /* Return code from ioctl */
/* Turn on update interrupts (one per second) */
#if defined(__alpha__) || defined(__sparc__)
/*
* Not all alpha kernels reject RTC_UIE_ON, but probably
* they should.
*/
rc = -1;
errno = EINVAL;
#else
rc = ioctl(rtc_fd, RTC_UIE_ON, 0);
#endif
if (rc == -1 && (errno == ENOTTY || errno == EINVAL)) {
/*
* This rtc device doesn't have interrupt functions.
* This is typical on an Alpha, where the Hardware
* Clock interrupts are used by the kernel for the
* system clock, so aren't at the user's disposal.
*/
if (debug)
printf(_
("%s does not have interrupt functions. "),
rtc_dev_name);
ret = busywait_for_rtc_clock_tick(rtc_fd);
} else if (rc == 0) {
#ifdef Wait_until_update_interrupt
unsigned long dummy;
/* this blocks until the next update interrupt */
rc = read(rtc_fd, &dummy, sizeof(dummy));
ret = 1;
if (rc == -1)
warn(_
("read() to %s to wait for clock tick failed"),
rtc_dev_name);
else
ret = 0;
#else
/*
* Just reading rtc_fd fails on broken hardware: no
* update interrupt comes and a bootscript with a
* hwclock call hangs
*/
fd_set rfds;
struct timeval tv;
/*
* Wait up to ten seconds for the next update
* interrupt
*/
FD_ZERO(&rfds);
FD_SET(rtc_fd, &rfds);
tv.tv_sec = 10;
tv.tv_usec = 0;
rc = select(rtc_fd + 1, &rfds, NULL, NULL, &tv);
ret = 1;
if (rc == -1)
warn(_
("select() to %s to wait for clock tick failed"),
rtc_dev_name);
else if (rc == 0)
warn(_
("select() to %s to wait for clock tick timed out"),
rtc_dev_name);
else
ret = 0;
#endif
/* Turn off update interrupts */
rc = ioctl(rtc_fd, RTC_UIE_OFF, 0);
if (rc == -1)
warn(_
("ioctl() to %s to turn off update interrupts failed"),
rtc_dev_name);
} else {
warn(_
("ioctl() to %s to turn on update interrupts "
"failed unexpectedly"), rtc_dev_name);
ret = 1;
}
}
return ret;
}
