xref: /netbsd-src/external/bsd/ntp/dist/ntpd/refclock_zyfer.c (revision eabc0478de71e4e011a5b4e0392741e01d491794)

/*	$NetBSD: refclock_zyfer.c,v 1.6 2024/08/18 20:47:19 christos Exp $	*/

/*
 * refclock_zyfer - clock driver for the Zyfer GPSTarplus Clock
 *
 * Harlan Stenn, Jan 2002
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#if defined(REFCLOCK) && defined(CLOCK_ZYFER)

#include "ntpd.h"
#include "ntp_io.h"
#include "ntp_refclock.h"
#include "ntp_stdlib.h"
#include "ntp_unixtime.h"
#include "ntp_calgps.h"

#include <stdio.h>
#include <ctype.h>

#if defined(HAVE_TERMIOS_H)
# include <termios.h>
#elif defined(HAVE_SYS_TERMIOS_H)
# include <sys/termios.h>
#endif
#ifdef HAVE_SYS_PPSCLOCK_H
# include <sys/ppsclock.h>
#endif

/*
 * This driver provides support for the TOD serial port of a Zyfer GPStarplus.
 * This clock also provides PPS as well as IRIG outputs.
 * Precision is limited by the serial driver, etc.
 *
 * If I was really brave I'd hack/generalize the serial driver to deal
 * with arbitrary on-time characters.  This clock *begins* the stream with
 * `!`, the on-time character, and the string is *not* EOL-terminated.
 *
 * Configure the beast for 9600, 8N1.  While I see leap-second stuff
 * in the documentation, the published specs on the TOD format only show
 * the seconds going to '59'.  I see no leap warning in the TOD format.
 *
 * The clock sends the following message once per second:
 *
 *	!TIME,2002,017,07,59,32,2,4,1
 *	      YYYY DDD HH MM SS m T O
 *
 *	!		On-time character
 *	YYYY		Year
 *	DDD	001-366	Day of Year
 *	HH	00-23	Hour
 *	MM	00-59	Minute
 *	SS	00-59	Second (probably 00-60)
 *	m	1-5	Time Mode:
 *			1 = GPS time
 *			2 = UTC time
 *			3 = LGPS time (Local GPS)
 *			4 = LUTC time (Local UTC)
 *			5 = Manual time
 *	T	4-9	Time Figure Of Merit:
 *			4         x <= 1us
 *			5   1us < x <= 10 us
 *			6  10us < x <= 100us
 *			7 100us < x <= 1ms
 *			8   1ms < x <= 10ms
 *			9  10ms < x
 *	O	0-4	Operation Mode:
 *			0 Warm-up
 *			1 Time Locked
 *			2 Coasting
 *			3 Recovering
 *			4 Manual
 *
 */

/*
 * Interface definitions
 */
#define	DEVICE		"/dev/zyfer%d" /* device name and unit */
#define	SPEED232	B9600	/* uart speed (9600 baud) */
#define	PRECISION	(-20)	/* precision assumed (about 1 us) */
#define	REFID		"GPS\0"	/* reference ID */
#define	DESCRIPTION	"Zyfer GPStarplus" /* WRU */

#define	LENZYFER	29	/* timecode length */

/*
 * Unit control structure
 */
struct zyferunit {
	u_char	Rcvbuf[LENZYFER + 1];
	u_char	polled;		/* poll message flag */
	int	pollcnt;
	l_fp    tstamp;         /* timestamp of last poll */
	int	Rcvptr;
};

/*
 * Function prototypes
 */
static	int	zyfer_start	(int, struct peer *);
static	void	zyfer_shutdown	(int, struct peer *);
static	void	zyfer_receive	(struct recvbuf *);
static	void	zyfer_poll	(int, struct peer *);

/*
 * Transfer vector
 */
struct	refclock refclock_zyfer = {
	zyfer_start,		/* start up driver */
	zyfer_shutdown,		/* shut down driver */
	zyfer_poll,		/* transmit poll message */
	noentry,		/* not used (old zyfer_control) */
	noentry,		/* initialize driver (not used) */
	noentry,		/* not used (old zyfer_buginfo) */
	NOFLAGS			/* not used */
};


/*
 * zyfer_start - open the devices and initialize data for processing
 */
static int
zyfer_start(
	int unit,
	struct peer *peer
	)
{
	register struct zyferunit *up;
	struct refclockproc *pp;
	int fd;
	char device[20];

	/*
	 * Open serial port.
	 * Something like LDISC_ACTS that looked for ! would be nice...
	 */
	snprintf(device, sizeof(device), DEVICE, unit);
	fd = refclock_open(&peer->srcadr, device, SPEED232, LDISC_RAW);
	if (fd <= 0)
		return (0);

	msyslog(LOG_NOTICE, "zyfer(%d) fd: %d dev <%s>", unit, fd, device);

	/*
	 * Allocate and initialize unit structure
	 */
	up = emalloc(sizeof(struct zyferunit));
	memset(up, 0, sizeof(struct zyferunit));
	pp = peer->procptr;
	pp->io.clock_recv = zyfer_receive;
	pp->io.srcclock = peer;
	pp->io.datalen = 0;
	pp->io.fd = fd;
	if (!io_addclock(&pp->io)) {
		close(fd);
		pp->io.fd = -1;
		free(up);
		return (0);
	}
	pp->unitptr = up;

	/*
	 * Initialize miscellaneous variables
	 */
	peer->precision = PRECISION;
	pp->clockdesc = DESCRIPTION;
	memcpy((char *)&pp->refid, REFID, 4);
	up->pollcnt = 2;
	up->polled = 0;		/* May not be needed... */

	return (1);
}


/*
 * zyfer_shutdown - shut down the clock
 */
static void
zyfer_shutdown(
	int unit,
	struct peer *peer
	)
{
	register struct zyferunit *up;
	struct refclockproc *pp;

	pp = peer->procptr;
	up = pp->unitptr;
	if (pp->io.fd != -1)
		io_closeclock(&pp->io);
	if (up != NULL)
		free(up);
}


/*
 * zyfer_receive - receive data from the serial interface
 */
static void
zyfer_receive(
	struct recvbuf *rbufp
	)
{
	register struct zyferunit *up;
	struct refclockproc *pp;
	struct peer *peer;
	int tmode;		/* Time mode */
	int tfom;		/* Time Figure Of Merit */
	int omode;		/* Operation mode */
	u_char *p;

	TCivilDate	tsdoy;
	TNtpDatum	tsntp;
	l_fp		tfrac;

	peer = rbufp->recv_peer;
	pp = peer->procptr;
	up = pp->unitptr;
	p = (u_char *) &rbufp->recv_space;
	/*
	 * If lencode is 0:
	 * - if *rbufp->recv_space is !
	 * - - call refclock_gtlin to get things going
	 * - else flush
	 * else stuff it on the end of lastcode
	 * If we don't have LENZYFER bytes
	 * - wait for more data
	 * Crack the beast, and if it's OK, process it.
	 *
	 * We use refclock_gtlin() because we might use LDISC_CLK.
	 *
	 * Under FreeBSD, we get the ! followed by two 14-byte packets.
	 */

	if (pp->lencode >= LENZYFER)
		pp->lencode = 0;

	if (!pp->lencode) {
		if (*p == '!')
			pp->lencode = refclock_gtlin(rbufp, pp->a_lastcode,
						     BMAX, &pp->lastrec);
		else
			return;
	} else {
		memcpy(pp->a_lastcode + pp->lencode, p, rbufp->recv_length);
		pp->lencode += rbufp->recv_length;
		pp->a_lastcode[pp->lencode] = '\0';
	}

	if (pp->lencode < LENZYFER)
		return;

	record_clock_stats(&peer->srcadr, pp->a_lastcode);

	/*
	 * We get down to business, check the timecode format and decode
	 * its contents. If the timecode has invalid length or is not in
	 * proper format, we declare bad format and exit.
	 */

	if (pp->lencode != LENZYFER) {
		refclock_report(peer, CEVNT_BADTIME);
		return;
	}

	/*
	 * Timecode sample: "!TIME,2002,017,07,59,32,2,4,1"
	 */
	if (sscanf(pp->a_lastcode, "!TIME,%4d,%3d,%2d,%2d,%2d,%d,%d,%d",
		   &pp->year, &pp->day, &pp->hour, &pp->minute, &pp->second,
		   &tmode, &tfom, &omode) != 8) {
		refclock_report(peer, CEVNT_BADREPLY);
		return;
	}

	if (tmode != 2) {
		refclock_report(peer, CEVNT_BADTIME);
		return;
	}

	/* Should we make sure tfom is 4? */

	if (omode != 1) {
		pp->leap = LEAP_NOTINSYNC;
		return;
	}

	/* treat GPS input as subject to era warps */
	ZERO(tsdoy);
	ZERO(tfrac);

	tsdoy.year    = pp->year;
	tsdoy.yearday = pp->day;
	tsdoy.hour    = pp->hour;
	tsdoy.minute  = pp->minute;
	tsdoy.second  = pp->second;

	/* note: We kept 'month' and 'monthday' zero above. That forces
	 * day-of-year based calculation now:
	 */
	tsntp = gpsntp_from_calendar(&tsdoy, tfrac);
	tfrac = ntpfp_from_ntpdatum(&tsntp);
	refclock_process_offset(pp, tfrac, pp->lastrec, pp->fudgetime1);

	/*
	 * Good place for record_clock_stats()
	 */
	up->pollcnt = 2;

	if (up->polled) {
		up->polled = 0;
		refclock_receive(peer);
	}
}


/*
 * zyfer_poll - called by the transmit procedure
 */
static void
zyfer_poll(
	int unit,
	struct peer *peer
	)
{
	register struct zyferunit *up;
	struct refclockproc *pp;

	/*
	 * We don't really do anything here, except arm the receiving
	 * side to capture a sample and check for timeouts.
	 */
	pp = peer->procptr;
	up = pp->unitptr;
	if (!up->pollcnt)
		refclock_report(peer, CEVNT_TIMEOUT);
	else
		up->pollcnt--;
	pp->polls++;
	up->polled = 1;
}

#else
NONEMPTY_TRANSLATION_UNIT
#endif /* REFCLOCK */