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/*
chronyd/chronyc - Programs for keeping computer clocks accurate.
**********************************************************************
* Copyright (C) Uwe Kleine-König, Pengutronix 2021
* Copyright (C) Ahmad Fatoum, Pengutronix 2024
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
**********************************************************************
=======================================================================
RTC refclock driver.
*/
#include "config.h"
#include "refclock.h"
#ifdef FEAT_RTC
#include <linux/rtc.h>
#include "conf.h"
#include "local.h"
#include "logging.h"
#include "memory.h"
#include "sched.h"
#include "util.h"
#include "rtc_linux.h"
struct refrtc_instance {
int fd;
int polling;
int utc;
};
static int refrtc_add_sample(RCL_Instance instance, struct timespec *now,
time_t rtc_sec, long rtc_nsec)
{
struct timespec rtc_ts;
int status;
rtc_ts.tv_sec = rtc_sec;
rtc_ts.tv_nsec = rtc_nsec;
status = RCL_AddSample(instance, now, &rtc_ts, LEAP_Normal, 1);
return status;
}
static void refrtc_read_after_uie(int rtcfd, int event, void *data)
{
RCL_Instance instance = (RCL_Instance)data;
struct refrtc_instance *rtc = RCL_GetDriverData(instance);
struct timespec now;
time_t rtc_sec;
int status;
status = RTC_Linux_CheckInterrupt(rtcfd);
if (status < 0) {
SCH_RemoveFileHandler(rtcfd);
RTC_Linux_SwitchInterrupt(rtcfd, 0); /* Likely to raise error too, but just to be sure... */
close(rtcfd);
rtc->fd = -1;
return;
} else if (status == 0) {
/* Wait for the next interrupt, this one may be bogus */
return;
}
rtc_sec = RTC_Linux_ReadTimeAfterInterrupt(rtcfd, rtc->utc, NULL, &now);
if (rtc_sec == (time_t)-1)
return;
refrtc_add_sample(instance, &now, rtc_sec, 0);
}
static int refrtc_initialise(RCL_Instance instance)
{
const char *options[] = {"utc", NULL};
struct refrtc_instance *rtc;
int rtcfd, status;
const char *path;
RCL_CheckDriverOptions(instance, options);
if (CNF_GetRtcSync() || CNF_GetRtcFile())
LOG_FATAL("RTC refclock cannot be used together with rtcsync or rtcfile");
path = RCL_GetDriverParameter(instance);
rtcfd = open(path, O_RDONLY);
if (rtcfd < 0)
LOG_FATAL("Could not open RTC device %s : %s", path, strerror(errno));
/* Close on exec */
UTI_FdSetCloexec(rtcfd);
rtc = MallocNew(struct refrtc_instance);
rtc->fd = rtcfd;
rtc->utc = RCL_GetDriverOption(instance, "utc") ? 1 : 0;
RCL_SetDriverData(instance, rtc);
/* Try to enable update interrupts */
status = RTC_Linux_SwitchInterrupt(rtcfd, 1);
if (status) {
SCH_AddFileHandler(rtcfd, SCH_FILE_INPUT, refrtc_read_after_uie, instance);
rtc->polling = 0;
} else {
LOG(LOGS_INFO, "Falling back to polling for %s", path);
rtc->polling = 1;
}
return 1;
}
static void refrtc_finalise(RCL_Instance instance)
{
struct refrtc_instance *rtc;
rtc = RCL_GetDriverData(instance);
if (rtc->fd >= 0) {
if (!rtc->polling) {
SCH_RemoveFileHandler(rtc->fd);
RTC_Linux_SwitchInterrupt(rtc->fd, 0);
}
close(rtc->fd);
}
Free(rtc);
}
static int refrtc_poll(RCL_Instance instance)
{
struct refrtc_instance *rtc;
struct timespec now;
time_t rtc_sec;
rtc = RCL_GetDriverData(instance);
if (!rtc->polling)
return 0;
rtc_sec = RTC_Linux_ReadTimeNow(rtc->fd, rtc->utc, NULL, &now);
if (rtc_sec == (time_t)-1)
return 0;
/* As the rtc has a resolution of 1s, only add half a second */
return refrtc_add_sample(instance, &now, rtc_sec, 500000000);
}
RefclockDriver RCL_RTC_driver = {
refrtc_initialise,
refrtc_finalise,
refrtc_poll
};
#else
RefclockDriver RCL_RTC_driver = { NULL, NULL, NULL };
#endif
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