/*
* rtc.c - Use /dev/rtc for clock access
*/
#include <asm/ioctl.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#include "monotonic.h"
#include "nls.h"
#include "hwclock.h"
/*
* Get defines for rtc stuff.
*
* Getting the rtc defines is nontrivial. The obvious way is by including
* <linux/mc146818rtc.h> but that again includes <asm/io.h> which again
* includes ... and on sparc and alpha this gives compilation errors for
* many kernel versions. So, we give the defines ourselves here. Moreover,
* some Sparc person decided to be incompatible, and used a struct rtc_time
* different from that used in mc146818rtc.h.
*/
/*
* On Sparcs, there is a <asm/rtc.h> that defines different ioctls (that are
* required on my machine). However, this include file does not exist on
* other architectures.
*/
/* One might do:
#ifdef __sparc__
# include <asm/rtc.h>
#endif
*/
#ifdef __sparc__
/* The following is roughly equivalent */
struct sparc_rtc_time
{
int sec; /* Seconds 0-59 */
int min; /* Minutes 0-59 */
int hour; /* Hour 0-23 */
int dow; /* Day of the week 1-7 */
int dom; /* Day of the month 1-31 */
int month; /* Month of year 1-12 */
int year; /* Year 0-99 */
};
#define RTCGET _IOR('p', 20, struct sparc_rtc_time)
#define RTCSET _IOW('p', 21, struct sparc_rtc_time)
#endif
/*
* struct rtc_time is present since 1.3.99.
* Earlier (since 1.3.89), a struct tm was used.
*/
struct linux_rtc_time {
int tm_sec;
int tm_min;
int tm_hour;
int tm_mday;
int tm_mon;
int tm_year;
int tm_wday;
int tm_yday;
int tm_isdst;
};
/* RTC_RD_TIME etc have this definition since 1.99.9 (pre2.0-9) */
#ifndef RTC_RD_TIME
# define RTC_RD_TIME _IOR('p', 0x09, struct linux_rtc_time)
# define RTC_SET_TIME _IOW('p', 0x0a, struct linux_rtc_time)
# define RTC_UIE_ON _IO('p', 0x03) /* Update int. enable on */
# define RTC_UIE_OFF _IO('p', 0x04) /* Update int. enable off */
#endif
/* RTC_EPOCH_READ and RTC_EPOCH_SET are present since 2.0.34 and 2.1.89 */
#ifndef RTC_EPOCH_READ
# define RTC_EPOCH_READ _IOR('p', 0x0d, unsigned long) /* Read epoch */
# define RTC_EPOCH_SET _IOW('p', 0x0e, unsigned long) /* Set epoch */
#endif
/*
* /dev/rtc is conventionally chardev 10/135
* ia64 uses /dev/efirtc, chardev 10/136
* devfs (obsolete) used /dev/misc/... for miscdev
* new RTC framework + udev uses dynamic major and /dev/rtc0.../dev/rtcN
* ... so we need an overridable default
*/
/* default or user defined dev (by hwclock --rtc=<path>) */
static const char *rtc_dev_name;
static int rtc_dev_fd = -1;
static void close_rtc(void)
{
if (rtc_dev_fd != -1)
close(rtc_dev_fd);
rtc_dev_fd = -1;
}
static int open_rtc(const struct hwclock_control *ctl)
{
static const char *fls[] = {
#ifdef __ia64__
"/dev/efirtc",
"/dev/misc/efirtc",
#endif
"/dev/rtc0",
"/dev/rtc",
"/dev/misc/rtc"
};
size_t i;
if (rtc_dev_fd != -1)
return rtc_dev_fd;
/* --rtc option has been given */
if (ctl->rtc_dev_name) {
rtc_dev_name = ctl->rtc_dev_name;
rtc_dev_fd = open(rtc_dev_name, O_RDONLY);
} else {
for (i = 0; i < ARRAY_SIZE(fls); i++) {
if (ctl->verbose)
printf(_("Trying to open: %s\n"), fls[i]);
rtc_dev_fd = open(fls[i], O_RDONLY);
if (rtc_dev_fd < 0
&& (errno == ENOENT || errno == ENODEV))
continue;
rtc_dev_name = fls[i];
break;
}
if (rtc_dev_fd < 0)
rtc_dev_name = *fls; /* default for error messages */
}
if (rtc_dev_fd != -1)
atexit(close_rtc);
return rtc_dev_fd;
}
static int open_rtc_or_exit(const struct hwclock_control *ctl)
{
int rtc_fd = open_rtc(ctl);
if (rtc_fd < 0) {
warn(_("cannot open rtc device"));
hwclock_exit(ctl, EXIT_FAILURE);
}
return rtc_fd;
}
static int do_rtc_read_ioctl(int rtc_fd, struct tm *tm)
{
int rc = -1;
char *ioctlname;
#ifdef __sparc__
/* some but not all sparcs use a different ioctl and struct */
struct sparc_rtc_time stm;
#endif
ioctlname = "RTC_RD_TIME";
rc = ioctl(rtc_fd, RTC_RD_TIME, tm);
#ifdef __sparc__
if (rc == -1) { /* sparc sbus */
ioctlname = "RTCGET";
rc = ioctl(rtc_fd, RTCGET, &stm);
if (rc == 0) {
tm->tm_sec = stm.sec;
tm->tm_min = stm.min;
tm->tm_hour = stm.hour;
tm->tm_mday = stm.dom;
tm->tm_mon = stm.month - 1;
tm->tm_year = stm.year - 1900;
tm->tm_wday = stm.dow - 1;
tm->tm_yday = -1; /* day in the year */
}
}
#endif
if (rc == -1) {
warn(_("ioctl(%s) to %s to read the time failed"),
ioctlname, rtc_dev_name);
return -1;
}
tm->tm_isdst = -1; /* don't know whether it's dst */
return 0;
}
/*
* Wait for the top of a clock tick by reading /dev/rtc in a busy loop
* until we see it. This function is used for rtc drivers without ioctl
* interrupts. 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.
*/
static int busywait_for_rtc_clock_tick(const struct hwclock_control *ctl,
const int rtc_fd)
{
struct tm start_time;
/* The time when we were called (and started waiting) */
struct tm nowtime;
int rc;
struct timeval begin, now;
if (ctl->verbose) {
printf("ioctl(%d, RTC_UIE_ON, 0): %s\n",
rtc_fd, strerror(errno));
printf(_("Waiting in loop for time from %s to change\n"),
rtc_dev_name);
}
if (do_rtc_read_ioctl(rtc_fd, &start_time))
return 1;
/*
* Wait for change. Should be within a second, but in case
* something weird happens, we have a time limit (1.5s) on this loop
* to reduce the impact of this failure.
*/
gettime_monotonic(&begin);
do {
rc = do_rtc_read_ioctl(rtc_fd, &nowtime);
if (rc || start_time.tm_sec != nowtime.tm_sec)
break;
gettime_monotonic(&now);
if (time_diff(now, begin) > 1.5) {
warnx(_("Timed out waiting for time change."));
return 1;
}
} while (1);
if (rc)
return 1;
return 0;
}
/*
* 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;
}
static int read_hardware_clock_rtc(const struct hwclock_control *ctl,
struct tm *tm)
{
int rtc_fd, rc;
rtc_fd = open_rtc_or_exit(ctl);
/* Read the RTC time/date, return answer via tm */
rc = do_rtc_read_ioctl(rtc_fd, tm);
return rc;
}
/*
* Set the Hardware Clock to the broken down time <new_broken_time>. Use
* ioctls to "rtc" device /dev/rtc.
*/
static int set_hardware_clock_rtc(const struct hwclock_control *ctl,
const struct tm *new_broken_time)
{
int rc = -1;
int rtc_fd;
char *ioctlname;
rtc_fd = open_rtc_or_exit(ctl);
ioctlname = "RTC_SET_TIME";
rc = ioctl(rtc_fd, RTC_SET_TIME, new_broken_time);
#ifdef __sparc__
if (rc == -1) { /* sparc sbus */
struct sparc_rtc_time stm;
stm.sec = new_broken_time->tm_sec;
stm.min = new_broken_time->tm_min;
stm.hour = new_broken_time->tm_hour;
stm.dom = new_broken_time->tm_mday;
stm.month = new_broken_time->tm_mon + 1;
stm.year = new_broken_time->tm_year + 1900;
stm.dow = new_broken_time->tm_wday + 1;
ioctlname = "RTCSET";
rc = ioctl(rtc_fd, RTCSET, &stm);
}
#endif
if (rc == -1) {
warn(_("ioctl(%s) to %s to set the time failed"),
ioctlname, rtc_dev_name);
hwclock_exit(ctl, EXIT_FAILURE);
}
if (ctl->verbose)
printf(_("ioctl(%s) was successful.\n"), ioctlname);
return 0;
}
static int get_permissions_rtc(void)
{
return 0;
}
static const char *get_device_path(void)
{
return rtc_dev_name;
}
static struct clock_ops rtc_interface = {
N_("Using the rtc interface to the clock."),
get_permissions_rtc,
read_hardware_clock_rtc,
set_hardware_clock_rtc,
synchronize_to_clock_tick_rtc,
get_device_path,
};
/* return &rtc if /dev/rtc can be opened, NULL otherwise */
struct clock_ops *probe_for_rtc_clock(const struct hwclock_control *ctl)
{
const int rtc_fd = open_rtc(ctl);
if (rtc_fd < 0)
return NULL;
return &rtc_interface;
}
#ifdef __alpha__
/*
* Get the Hardware Clock epoch setting from the kernel.
*/
int get_epoch_rtc(const struct hwclock_control *ctl, unsigned long *epoch_p)
{
int rtc_fd;
rtc_fd = open_rtc(ctl);
if (rtc_fd < 0) {
warn(_("cannot open %s"), rtc_dev_name);
return 1;
}
if (ioctl(rtc_fd, RTC_EPOCH_READ, epoch_p) == -1) {
warn(_("ioctl(%d, RTC_EPOCH_READ, epoch_p) to %s failed"),
rtc_fd, rtc_dev_name);
return 1;
}
if (ctl->verbose)
printf(_("ioctl(%d, RTC_EPOCH_READ, epoch_p) to %s succeeded.\n"),
rtc_fd, rtc_dev_name);
return 0;
}
/*
* Set the Hardware Clock epoch in the kernel.
*/
int set_epoch_rtc(const struct hwclock_control *ctl)
{
int rtc_fd;
unsigned long epoch;
epoch = strtoul(ctl->epoch_option, NULL, 10);
/* There were no RTC clocks before 1900. */
if (epoch < 1900 || epoch == ULONG_MAX) {
warnx(_("invalid epoch '%s'."), ctl->epoch_option);
return 1;
}
rtc_fd = open_rtc(ctl);
if (rtc_fd < 0) {
warn(_("cannot open %s"), rtc_dev_name);
return 1;
}
if (ioctl(rtc_fd, RTC_EPOCH_SET, epoch) == -1) {
warn(_("ioctl(%d, RTC_EPOCH_SET, %lu) to %s failed"),
rtc_fd, epoch, rtc_dev_name);
return 1;
}
if (ctl->verbose)
printf(_("ioctl(%d, RTC_EPOCH_SET, %lu) to %s succeeded.\n"),
rtc_fd, epoch, rtc_dev_name);
return 0;
}
#endif /* __alpha__ */
