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/*
chronyd/chronyc - Programs for keeping computer clocks accurate.
**********************************************************************
* Copyright (C) Miroslav Lichvar 2013
*
* 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.
*
**********************************************************************
=======================================================================
PTP hardware clock (PHC) refclock driver.
*/
#include "config.h"
#include "refclock.h"
#ifdef FEAT_PHC
#include "sysincl.h"
#include <linux/ptp_clock.h>
#include "refclock.h"
#include "logging.h"
#include "util.h"
/* From linux/include/linux/posix-timers.h */
#define CPUCLOCK_MAX 3
#define CLOCKFD CPUCLOCK_MAX
#define CLOCKFD_MASK (CPUCLOCK_PERTHREAD_MASK|CPUCLOCK_CLOCK_MASK)
#define FD_TO_CLOCKID(fd) ((~(clockid_t) (fd) << 3) | CLOCKFD)
#define NUM_READINGS 10
static int no_sys_offset_ioctl = 0;
struct phc_reading {
struct timespec sys_ts1;
struct timespec phc_ts;;
struct timespec sys_ts2;
};
static double diff_ts(struct timespec *ts1, struct timespec *ts2)
{
return (ts1->tv_sec - ts2->tv_sec) + (ts1->tv_nsec - ts2->tv_nsec) / 1e9;
}
static int read_phc_ioctl(struct phc_reading *readings, int phc_fd, int n)
{
#if defined(PTP_SYS_OFFSET) && NUM_READINGS <= PTP_MAX_SAMPLES
struct ptp_sys_offset sys_off;
int i;
/* Silence valgrind */
memset(&sys_off, 0, sizeof (sys_off));
sys_off.n_samples = n;
if (ioctl(phc_fd, PTP_SYS_OFFSET, &sys_off)) {
LOG(LOGS_ERR, LOGF_Refclock, "ioctl(PTP_SYS_OFFSET) failed : %s", strerror(errno));
return 0;
}
for (i = 0; i < n; i++) {
readings[i].sys_ts1.tv_sec = sys_off.ts[i * 2].sec;
readings[i].sys_ts1.tv_nsec = sys_off.ts[i * 2].nsec;
readings[i].phc_ts.tv_sec = sys_off.ts[i * 2 + 1].sec;
readings[i].phc_ts.tv_nsec = sys_off.ts[i * 2 + 1].nsec;
readings[i].sys_ts2.tv_sec = sys_off.ts[i * 2 + 2].sec;
readings[i].sys_ts2.tv_nsec = sys_off.ts[i * 2 + 2].nsec;
}
return 1;
#else
/* Not available */
return 0;
#endif
}
static int read_phc_user(struct phc_reading *readings, int phc_fd, int n)
{
clockid_t phc_id;
int i;
phc_id = FD_TO_CLOCKID(phc_fd);
for (i = 0; i < n; i++) {
if (clock_gettime(CLOCK_REALTIME, &readings[i].sys_ts1) ||
clock_gettime(phc_id, &readings[i].phc_ts) ||
clock_gettime(CLOCK_REALTIME, &readings[i].sys_ts2)) {
LOG(LOGS_ERR, LOGF_Refclock, "clock_gettime() failed : %s", strerror(errno));
return 0;
}
}
return 1;
}
static int phc_initialise(RCL_Instance instance)
{
struct ptp_clock_caps caps;
int phc_fd;
char *path;
path = RCL_GetDriverParameter(instance);
phc_fd = open(path, O_RDONLY);
if (phc_fd < 0) {
LOG_FATAL(LOGF_Refclock, "open() failed on %s", path);
return 0;
}
/* Make sure it is a PHC */
if (ioctl(phc_fd, PTP_CLOCK_GETCAPS, &caps)) {
LOG_FATAL(LOGF_Refclock, "ioctl(PTP_CLOCK_GETCAPS) failed : %s", strerror(errno));
return 0;
}
UTI_FdSetCloexec(phc_fd);
RCL_SetDriverData(instance, (void *)(long)phc_fd);
return 1;
}
static void phc_finalise(RCL_Instance instance)
{
close((long)RCL_GetDriverData(instance));
}
static int phc_poll(RCL_Instance instance)
{
struct phc_reading readings[NUM_READINGS];
struct timeval tv;
double offset = 0.0, delay, best_delay = 0.0;
int i, phc_fd, best;
phc_fd = (long)RCL_GetDriverData(instance);
if (!no_sys_offset_ioctl) {
if (!read_phc_ioctl(readings, phc_fd, NUM_READINGS)) {
no_sys_offset_ioctl = 1;
return 0;
}
} else {
if (!read_phc_user(readings, phc_fd, NUM_READINGS))
return 0;
}
/* Find the fastest reading */
for (i = 0; i < NUM_READINGS; i++) {
delay = diff_ts(&readings[i].sys_ts2, &readings[i].sys_ts1);
if (!i || best_delay > delay) {
best = i;
best_delay = delay;
}
}
offset = diff_ts(&readings[best].phc_ts, &readings[best].sys_ts2) + best_delay / 2.0;
tv.tv_sec = readings[best].sys_ts2.tv_sec;
tv.tv_usec = readings[best].sys_ts2.tv_nsec / 1000;
DEBUG_LOG(LOGF_Refclock, "PHC offset: %+.9f delay: %.9f", offset, best_delay);
return RCL_AddSample(instance, &tv, offset, LEAP_Normal);
}
RefclockDriver RCL_PHC_driver = {
phc_initialise,
phc_finalise,
phc_poll
};
#else
RefclockDriver RCL_PHC_driver = { NULL, NULL, NULL };
#endif
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