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![Richard Cochran](/assets/img/avatar_default.png)
This patch adds an infrastructure for hardware clocks that implement IEEE 1588, the Precision Time Protocol (PTP). A class driver offers a registration method to particular hardware clock drivers. Each clock is presented as a standard POSIX clock. The ancillary clock features are exposed in two different ways, via the sysfs and by a character device. Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: John Stultz <john.stultz@linaro.org>
381 lines
8.7 KiB
C
381 lines
8.7 KiB
C
/*
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* PTP 1588 clock support - User space test program
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*
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* Copyright (C) 2010 OMICRON electronics GmbH
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <errno.h>
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#include <fcntl.h>
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#include <math.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/timex.h>
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#include <sys/types.h>
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#include <time.h>
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#include <unistd.h>
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#include <linux/ptp_clock.h>
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#define DEVICE "/dev/ptp0"
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#ifndef ADJ_SETOFFSET
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#define ADJ_SETOFFSET 0x0100
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#endif
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#ifndef CLOCK_INVALID
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#define CLOCK_INVALID -1
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#endif
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/* When glibc offers the syscall, this will go away. */
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#include <sys/syscall.h>
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static int clock_adjtime(clockid_t id, struct timex *tx)
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{
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return syscall(__NR_clock_adjtime, id, tx);
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}
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static clockid_t get_clockid(int fd)
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{
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#define CLOCKFD 3
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#define FD_TO_CLOCKID(fd) ((~(clockid_t) (fd) << 3) | CLOCKFD)
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return FD_TO_CLOCKID(fd);
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}
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static void handle_alarm(int s)
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{
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printf("received signal %d\n", s);
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}
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static int install_handler(int signum, void (*handler)(int))
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{
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struct sigaction action;
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sigset_t mask;
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/* Unblock the signal. */
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sigemptyset(&mask);
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sigaddset(&mask, signum);
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sigprocmask(SIG_UNBLOCK, &mask, NULL);
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/* Install the signal handler. */
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action.sa_handler = handler;
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action.sa_flags = 0;
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sigemptyset(&action.sa_mask);
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sigaction(signum, &action, NULL);
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return 0;
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}
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static long ppb_to_scaled_ppm(int ppb)
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{
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/*
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* The 'freq' field in the 'struct timex' is in parts per
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* million, but with a 16 bit binary fractional field.
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* Instead of calculating either one of
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*
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* scaled_ppm = (ppb / 1000) << 16 [1]
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* scaled_ppm = (ppb << 16) / 1000 [2]
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*
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* we simply use double precision math, in order to avoid the
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* truncation in [1] and the possible overflow in [2].
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*/
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return (long) (ppb * 65.536);
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}
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static void usage(char *progname)
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{
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fprintf(stderr,
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"usage: %s [options]\n"
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" -a val request a one-shot alarm after 'val' seconds\n"
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" -A val request a periodic alarm every 'val' seconds\n"
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" -c query the ptp clock's capabilities\n"
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" -d name device to open\n"
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" -e val read 'val' external time stamp events\n"
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" -f val adjust the ptp clock frequency by 'val' ppb\n"
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" -g get the ptp clock time\n"
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" -h prints this message\n"
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" -p val enable output with a period of 'val' nanoseconds\n"
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" -P val enable or disable (val=1|0) the system clock PPS\n"
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" -s set the ptp clock time from the system time\n"
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" -S set the system time from the ptp clock time\n"
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" -t val shift the ptp clock time by 'val' seconds\n",
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progname);
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}
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int main(int argc, char *argv[])
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{
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struct ptp_clock_caps caps;
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struct ptp_extts_event event;
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struct ptp_extts_request extts_request;
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struct ptp_perout_request perout_request;
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struct timespec ts;
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struct timex tx;
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static timer_t timerid;
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struct itimerspec timeout;
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struct sigevent sigevent;
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char *progname;
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int c, cnt, fd;
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char *device = DEVICE;
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clockid_t clkid;
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int adjfreq = 0x7fffffff;
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int adjtime = 0;
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int capabilities = 0;
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int extts = 0;
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int gettime = 0;
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int oneshot = 0;
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int periodic = 0;
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int perout = -1;
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int pps = -1;
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int settime = 0;
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progname = strrchr(argv[0], '/');
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progname = progname ? 1+progname : argv[0];
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while (EOF != (c = getopt(argc, argv, "a:A:cd:e:f:ghp:P:sSt:v"))) {
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switch (c) {
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case 'a':
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oneshot = atoi(optarg);
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break;
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case 'A':
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periodic = atoi(optarg);
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break;
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case 'c':
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capabilities = 1;
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break;
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case 'd':
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device = optarg;
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break;
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case 'e':
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extts = atoi(optarg);
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break;
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case 'f':
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adjfreq = atoi(optarg);
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break;
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case 'g':
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gettime = 1;
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break;
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case 'p':
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perout = atoi(optarg);
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break;
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case 'P':
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pps = atoi(optarg);
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break;
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case 's':
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settime = 1;
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break;
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case 'S':
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settime = 2;
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break;
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case 't':
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adjtime = atoi(optarg);
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break;
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case 'h':
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usage(progname);
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return 0;
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case '?':
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default:
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usage(progname);
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return -1;
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}
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}
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fd = open(device, O_RDWR);
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if (fd < 0) {
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fprintf(stderr, "opening %s: %s\n", device, strerror(errno));
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return -1;
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}
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clkid = get_clockid(fd);
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if (CLOCK_INVALID == clkid) {
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fprintf(stderr, "failed to read clock id\n");
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return -1;
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}
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if (capabilities) {
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if (ioctl(fd, PTP_CLOCK_GETCAPS, &caps)) {
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perror("PTP_CLOCK_GETCAPS");
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} else {
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printf("capabilities:\n"
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" %d maximum frequency adjustment (ppb)\n"
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" %d programmable alarms\n"
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" %d external time stamp channels\n"
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" %d programmable periodic signals\n"
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" %d pulse per second\n",
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caps.max_adj,
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caps.n_alarm,
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caps.n_ext_ts,
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caps.n_per_out,
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caps.pps);
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}
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}
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if (0x7fffffff != adjfreq) {
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memset(&tx, 0, sizeof(tx));
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tx.modes = ADJ_FREQUENCY;
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tx.freq = ppb_to_scaled_ppm(adjfreq);
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if (clock_adjtime(clkid, &tx)) {
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perror("clock_adjtime");
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} else {
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puts("frequency adjustment okay");
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}
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}
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if (adjtime) {
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memset(&tx, 0, sizeof(tx));
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tx.modes = ADJ_SETOFFSET;
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tx.time.tv_sec = adjtime;
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tx.time.tv_usec = 0;
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if (clock_adjtime(clkid, &tx) < 0) {
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perror("clock_adjtime");
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} else {
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puts("time shift okay");
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}
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}
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if (gettime) {
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if (clock_gettime(clkid, &ts)) {
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perror("clock_gettime");
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} else {
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printf("clock time: %ld.%09ld or %s",
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ts.tv_sec, ts.tv_nsec, ctime(&ts.tv_sec));
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}
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}
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if (settime == 1) {
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clock_gettime(CLOCK_REALTIME, &ts);
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if (clock_settime(clkid, &ts)) {
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perror("clock_settime");
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} else {
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puts("set time okay");
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}
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}
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if (settime == 2) {
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clock_gettime(clkid, &ts);
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if (clock_settime(CLOCK_REALTIME, &ts)) {
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perror("clock_settime");
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} else {
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puts("set time okay");
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}
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}
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if (extts) {
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memset(&extts_request, 0, sizeof(extts_request));
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extts_request.index = 0;
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extts_request.flags = PTP_ENABLE_FEATURE;
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if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
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perror("PTP_EXTTS_REQUEST");
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extts = 0;
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} else {
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puts("external time stamp request okay");
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}
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for (; extts; extts--) {
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cnt = read(fd, &event, sizeof(event));
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if (cnt != sizeof(event)) {
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perror("read");
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break;
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}
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printf("event index %u at %lld.%09u\n", event.index,
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event.t.sec, event.t.nsec);
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fflush(stdout);
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}
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/* Disable the feature again. */
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extts_request.flags = 0;
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if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
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perror("PTP_EXTTS_REQUEST");
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}
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}
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if (oneshot) {
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install_handler(SIGALRM, handle_alarm);
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/* Create a timer. */
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sigevent.sigev_notify = SIGEV_SIGNAL;
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sigevent.sigev_signo = SIGALRM;
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if (timer_create(clkid, &sigevent, &timerid)) {
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perror("timer_create");
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return -1;
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}
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/* Start the timer. */
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memset(&timeout, 0, sizeof(timeout));
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timeout.it_value.tv_sec = oneshot;
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if (timer_settime(timerid, 0, &timeout, NULL)) {
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perror("timer_settime");
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return -1;
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}
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pause();
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timer_delete(timerid);
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}
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if (periodic) {
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install_handler(SIGALRM, handle_alarm);
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/* Create a timer. */
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sigevent.sigev_notify = SIGEV_SIGNAL;
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sigevent.sigev_signo = SIGALRM;
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if (timer_create(clkid, &sigevent, &timerid)) {
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perror("timer_create");
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return -1;
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}
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/* Start the timer. */
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memset(&timeout, 0, sizeof(timeout));
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timeout.it_interval.tv_sec = periodic;
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timeout.it_value.tv_sec = periodic;
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if (timer_settime(timerid, 0, &timeout, NULL)) {
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perror("timer_settime");
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return -1;
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}
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while (1) {
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pause();
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}
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timer_delete(timerid);
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}
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if (perout >= 0) {
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if (clock_gettime(clkid, &ts)) {
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perror("clock_gettime");
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return -1;
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}
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memset(&perout_request, 0, sizeof(perout_request));
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perout_request.index = 0;
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perout_request.start.sec = ts.tv_sec + 2;
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perout_request.start.nsec = 0;
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perout_request.period.sec = 0;
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perout_request.period.nsec = perout;
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if (ioctl(fd, PTP_PEROUT_REQUEST, &perout_request)) {
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perror("PTP_PEROUT_REQUEST");
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} else {
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puts("periodic output request okay");
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}
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}
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if (pps != -1) {
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int enable = pps ? 1 : 0;
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if (ioctl(fd, PTP_ENABLE_PPS, enable)) {
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perror("PTP_ENABLE_PPS");
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} else {
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puts("pps for system time request okay");
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}
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}
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close(fd);
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return 0;
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}
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