refclock_ulink.c

网络时间协议NTP 源码 版本v4.2.0b 该源码用于linux平台下

/*
 * refclock_ulink - clock driver for Ultralink  WWVB receiver
 */

/***********************************************************************
 *                                                                     *
 * Copyright (c) David L. Mills 1992-1998                              *
 *                                                                     *
 * Permission to use, copy, modify, and distribute this software and   *
 * its documentation for any purpose and without fee is hereby         *
 * granted, provided that the above copyright notice appears in all    *
 * copies and that both the copyright notice and this permission       *
 * notice appear in supporting documentation, and that the name        *
 * University of Delaware not be used in advertising or publicity      *
 * pertaining to distribution of the software without specific,        *
 * written prior permission. The University of Delaware makes no       *
 * representations about the suitability this software for any         *
 * purpose. It is provided "as is" without express or implied          *
 * warranty.                                                           *
 **********************************************************************/

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

#if defined(REFCLOCK) && defined(CLOCK_ULINK)

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

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

/* This driver supports ultralink Model 320,325,330,331,332 WWVB radios
 *
 * this driver was based on the refclock_wwvb.c driver
 * in the ntp distribution.
 *
 * Fudge Factors
 *
 * fudge flag1 0 don't poll clock
 *             1 send poll character
 *
 * revision history:
 *		99/9/09 j.c.lang	original edit's
 *		99/9/11 j.c.lang	changed timecode parse to 
 *                                      match what the radio actually
 *                                      sends. 
 *              99/10/11 j.c.lang       added support for continous
 *                                      time code mode (dipsw2)
 *		99/11/26 j.c.lang	added support for 320 decoder
 *                                      (taken from Dave Strout's
 *                                      Model 320 driver)
 *		99/11/29 j.c.lang	added fudge flag 1 to control
 *					clock polling
 *		99/12/15 j.c.lang	fixed 320 quality flag
 *		01/02/21 s.l.smith	fixed 33x quality flag
 *					added more debugging stuff
 *					updated 33x time code explanation
 *		04/01/23 frank migge	added support for 325 decoder
 *                                      (tested with ULM325.F)
 *
 * Questions, bugs, ideas send to:
 *	Joseph C. Lang
 *	[e-mail]
 *
 *	Dave Strout
 *	[e-mail]
 *
 *      Frank Migge
 *      [e-mail]
 *
 *
 * on the Ultralink model 33X decoder Dip switch 2 controls
 * polled or continous timecode 
 * set fudge flag1 if using polled (needed for model 320 and 325)
 * dont set fudge flag1 if dip switch 2 is set on model 33x decoder
*/


/*
 * Interface definitions
 */
#define	DEVICE		"/dev/wwvb%d" /* device name and unit */
#define	SPEED232	B9600	/* uart speed (9600 baud) */
#define	PRECISION	(-10)	/* precision assumed (about 10 ms) */
#define	REFID		"WWVB"	/* reference ID */
#define	DESCRIPTION	"Ultralink WWVB Receiver" /* WRU */

#define	LEN33X		32	/* timecode length Model 33X and 325 */
#define LEN320		24	/* timecode length Model 320 */

#define	SIGLCHAR33x	'S'	/* signal strength identifier char 325 */
#define	SIGLCHAR325	'R'	/* signal strength identifier char 33x */

/*
 *  unit control structure
 */
struct ulinkunit {
	u_char	tcswitch;	/* timecode switch */
	l_fp	laststamp;	/* last receive timestamp */
};

/*
 * Function prototypes
 */
static	int	ulink_start	P((int, struct peer *));
static	void	ulink_shutdown	P((int, struct peer *));
static	void	ulink_receive	P((struct recvbuf *));
static	void	ulink_poll	P((int, struct peer *));

/*
 * Transfer vector
 */
struct	refclock refclock_ulink = {
	ulink_start,		/* start up driver */
	ulink_shutdown,		/* shut down driver */
	ulink_poll,		/* transmit poll message */
	noentry,		/* not used  */
	noentry,		/* not used  */
	noentry,		/* not used  */
	NOFLAGS
};


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

	/*
	 * Open serial port. Use CLK line discipline, if available.
	 */
	(void)sprintf(device, DEVICE, unit);
	if (!(fd = refclock_open(device, SPEED232, LDISC_CLK)))
		return (0);

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

	/*
	 * Initialize miscellaneous variables
	 */
	peer->precision = PRECISION;
	peer->burst = NSTAGE;
	pp->clockdesc = DESCRIPTION;
	memcpy((char *)&pp->refid, REFID, 4);
	return (1);
}


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

	pp = peer->procptr;
	up = (struct ulinkunit *)pp->unitptr;
	io_closeclock(&pp->io);
	free(up);
}


/*
 * ulink_receive - receive data from the serial interface
 */
static void
ulink_receive(
	struct recvbuf *rbufp
	)
{
	struct ulinkunit *up;
	struct refclockproc *pp;
	struct peer *peer;

	l_fp	trtmp;		/* arrival timestamp */
	int	quality;	/* quality indicator */
	int	temp;		/* int temp */
	char	syncchar;	/* synchronization indicator */
	char	leapchar;	/* leap indicator */
	char	modechar;	/* model 320 mode flag */
        char	siglchar;	/* model difference between 33x/325 */
	char	char_quality[2];	/* temp quality flag */

	/*
	 * Initialize pointers and read the timecode and timestamp
	 */
	peer = (struct peer *)rbufp->recv_srcclock;
	pp = peer->procptr;
	up = (struct ulinkunit *)pp->unitptr;
	temp = refclock_gtlin(rbufp, pp->a_lastcode, BMAX, &trtmp);

	/*
	 * Note we get a buffer and timestamp for both a <cr> and <lf>,
	 * but only the <cr> timestamp is retained. 
	 */
	if (temp == 0) {
		if (up->tcswitch == 0) {
			up->tcswitch = 1;
			up->laststamp = trtmp;
		} else
		    up->tcswitch = 0;
		return;
	}
	pp->lencode = temp;
	pp->lastrec = up->laststamp;
	up->laststamp = trtmp;
	up->tcswitch = 1;
#ifdef DEBUG
	if (debug)
		printf("ulink: timecode %d %s\n", pp->lencode,
		    pp->a_lastcode);
#endif

	/*
	 * 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.
	 */
	syncchar = leapchar = modechar = siglchar = ' ';
	switch (pp->lencode ) {
		case LEN33X:

		/*
                 * First we check if the format is 33x or 325:
		 *   <CR><LF>S9+D 00 YYYY+DDDUTCS HH:MM:SSL+5 (33x)
		 *   <CR><LF>R5_1C00LYYYY+DDDUTCS HH:MM:SSL+5 (325)
		 * simply by comparing if the signal level is 'S' or 'R'
                 */

                 if (sscanf(pp->a_lastcode, "%c%*31c",
                            &siglchar) == 1) {

                    if(siglchar == SIGLCHAR325) {

       		   /*
		    * decode for a Model 325 decoder.
		    * Timecode format from January 23, 2004 datasheet is:
                    *
		    *   <CR><LF>R5_1C00LYYYY+DDDUTCS HH:MM:SSL+5
                    *
		    *   R      WWVB decodersignal readability R1 - R5
		    *   5      R1 is unreadable, R5 is best
		    *   space  a space (0x20)
		    *   1      Data bit 0, 1, M (pos mark), or ? (unknown).
		    *   C      Reception from either (C)olorado or (H)awaii 
		    *   00     Hours since last good WWVB frame sync. Will 
		    *          be 00-99
		    *   space  Space char (0x20) or (0xa5) if locked to wwvb
		    *   YYYY   Current year, 2000-2099
		    *   +      Leap year indicator. '+' if a leap year,
		    *          a space (0x20) if not.
		    *   DDD    Day of year, 000 - 365.
		    *   UTC    Timezone (always 'UTC').
		    *   S      Daylight savings indicator
		    *             S - standard time (STD) in effect
		    *             O - during STD to DST day 0000-2400
		    *             D - daylight savings time (DST) in effect
		    *             I - during DST to STD day 0000-2400