/*
 * refclock_true - clock driver for the Kinemetrics/TrueTime receivers
 *	Receiver Version 3.0C - tested plain, with CLKLDISC
 */

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

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

/* This should be an atom clock but those are very hard to build.
 *
 * The PCL720 from P C Labs has an Intel 8253 lookalike, as well as a
 * bunch of TTL input and output pins, all brought out to the back
 * panel.  If you wire a PPS signal (such as the TTL PPS coming out of
 * a Kinemetrics/Truetime clock) to the 8253's GATE0, and then also
 * wire the 8253's OUT0 to the PCL720's INPUT3.BIT0, then we can read
 * CTR0 to get the number of uSecs since the last PPS upward swing,
 * mediated by reading OUT0 to find out if the counter has wrapped
 * around (this happens if more than 65535us (65ms) elapses between
 * the PPS event and our being called.)
 */
#ifdef ENABLE_PPS720
# undef min	/* XXX */
# undef max	/* XXX */
# include <machine/inline.h>
# include <sys/pcl720.h>
# include <sys/i8253.h>
# define PCL720_IOB 0x2a0	/* XXX */
# define PCL720_CTR 0		/* XXX */
#endif

/*
 * Support for Kinemetrics Truetime Receivers
 *	GPS/TM-TMD:
 *	XL-DC:		(a 151-602-210, reported by the driver as a GPS/TM-TMD)
 *	GPS-800 TCU:	(an 805-957 with the RS232 Talker/Listener module)
 *
 * WARNING: This driver depends on the system clock for year disambiguation.
 * It will thus not be usable for recovery if the system clock is trashed.
 *
 * Most of this code is originally from refclock_wwvb.c (now
 * refclock_spectracom.c) with thanks.
 * It has been so mangled that wwvb is not a recognizable ancestor.
 *
 * Timcode format: ADDD:HH:MM:SSQCL
 *	A - control A		(this is stripped before we see it)
 *	Q - Quality indication	(see below)
 *	C - Carriage return
 *	L - Line feed
 *
 * Quality codes indicate possible error of
 *   GPS-TM/TMD Receiver: (default quality codes for XL-DC)
 *       ?     +/- 1  milliseconds	#     +/- 100 microseconds
 *       *     +/- 10 microseconds	.     +/- 1   microsecond
 *     space   less than 1 microsecond
 *   TL-3 Receiver: (default quality codes for TL-3)
 *       ?     unknown quality (receiver is unlocked)
 *     space   +/- 5 milliseconds
 *
 * The carriage return start bit begins on 0 seconds and extends to 1 bit time.
 *
 * This driver used to support the 468-DC receiver, but
 * http://www.ebay.com/gds/468-DC-SATELLITE-CLOCK-/10000000006640775/g.html
 * tells us that the GOES sats were shut down in 2005.
 */


/*
 * Definitions
 */
#define	DEVICE		"/dev/true%d"
#define	SPEED232	B9600	/* 9600 baud */

/*
 * Radio interface parameters
 */
#define	PRECISION	(-10)		/* precision assumed (about 1 ms) */
#define	REFID		"TRUE"		/* reference id */
#define	NAME		"TRUETIME"	/* shortname */
#define	DESCRIPTION	"Kinemetrics/TrueTime Receiver"

/*
 * used by the state machine
 */
enum true_event	{e_Init, e_Huh, e_F18, e_F50, e_F51,
		 e_Location, e_TS, e_Max};
static const char *events[] = {"Init", "Huh", "F18", "F50", "F51",
			"Location", "TS"};
#define eventStr(x) (((int)x<(int)e_Max) ? events[(int)x] : "?")

enum true_state	{s_Base, s_InqTM, s_InqTCU, s_InqGOES,
		 s_Init, s_F18, s_F50, s_Start, s_Auto, s_Max};
static const char *states[] = {"Base", "InqTM", "InqTCU", "InqGOES",
			"Init", "F18", "F50", "Start", "Auto"};
#define stateStr(x) (((int)x<(int)s_Max) ? states[(int)x] : "?")

enum true_type	{t_unknown, t_tm, t_tcu, t_tl3, t_Max};
static const char *types[] = {"unknown", "tm", "tcu", "tl3"};
#define typeStr(x) (((int)x<(int)t_Max) ? types[(int)x] : "?")

/*
 * unit control structure
 */
struct true_unit {
	unsigned int	pollcnt;	/* poll message counter */
	unsigned int	station;	/* which station we are on */
	bool		polled;		/* Hand in a time sample? */
	enum true_state	state;		/* state machine */
	enum true_type	type;		/* what kind of clock is it? */
	int		unit;		/* save an extra copy of this */
	FILE		*debug;		/* debug logging file */
#ifdef ENABLE_PPS720
	int		pcl720init;	/* init flag for PCL 720 */
#endif
};

/*
 * Function prototypes
 */
static	bool	true_start	(int, struct peer *);
static	void	true_receive	(struct recvbuf *);
static	void	true_poll	(int, struct peer *);
static	void	true_send	(struct peer *, const char *);
static	void	true_doevent	(struct peer *, enum true_event);

#ifdef ENABLE_PPS720
static	unsigned long	true_sample720	(void);
#endif

/*
 * Transfer vector
 */
struct	refclock refclock_true = {
	NAME,			/* basename of driver */
	true_start,		/* start up driver */
	NULL,			/* shut down driver in the stabdard way */
	true_poll,		/* transmit poll message */
	NULL,			/* not used (old true_control) */
	NULL,			/* initialize driver (not used) */
	NULL			/* timer - not used */
};


NTP_PRINTF(2, 3)
static void
true_debug(struct peer *peer, const char *fmt, ...)
{
	va_list ap;
	int want_debugging, now_debugging;
	struct refclockproc *pp;
	struct true_unit *up;

	va_start(ap, fmt);
	pp = peer->procptr;
	up = pp->unitptr;

	want_debugging = (pp->sloppyclockflag & CLK_FLAG2) != 0;
	now_debugging = (up->debug != NULL);
	if (want_debugging != now_debugging)
	{
		if (want_debugging) {
			char filename[40];
			int fd;

			snprintf(filename, sizeof(filename),
				 "/tmp/true%d.debug", up->unit);
			fd = open(filename, O_CREAT | O_WRONLY | O_EXCL,
				  0600);
			if (fd >= 0 && (up->debug = fdopen(fd, "w"))) {
				static char buf[BUFSIZ];

				setvbuf(up->debug, buf, _IOLBF, BUFSIZ);
			}
		} else {
			fclose(up->debug);
			up->debug = NULL;
		}
	}

	if (up->debug) {
		fprintf(up->debug, "true%d: ", up->unit);
		vfprintf(up->debug, fmt, ap);
	}
	va_end(ap);
}

/*
 * true_start - open the devices and initialize data for processing
 */
static bool
true_start(
	int unit,
	struct peer *peer
	)
{
	struct true_unit *up;
	struct refclockproc *pp;
	char device[40];
	int fd;

	/*
	 * Open serial port
	 */
	snprintf(device, sizeof(device), DEVICE, unit);
	fd = refclock_open(peer->cfg.path ? peer->cfg.path : device,
			   peer->cfg.baud ? peer->cfg.baud : SPEED232, LDISC_STD);
	if (fd <= 0)
		/* coverity[leaked_handle] */
		return false;

	/*
	 * Allocate and initialize unit structure
	 */
	up = emalloc_zero(sizeof(*up));
	pp = peer->procptr;
	pp->io.clock_recv = true_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 false;
	}
	pp->unitptr = up;

	/*
	 * Initialize miscellaneous variables
	 */
	peer->precision = PRECISION;
	pp->clockname = NAME;
	pp->clockdesc = DESCRIPTION;
	memcpy(&pp->refid, REFID, REFIDLEN);
	peer->sstclktype = CTL_SST_TS_UHF;
	up->pollcnt = 2;
	up->type = t_unknown;
	up->state = s_Base;

	/*
	 * Send a CTRL-C character at the start,
	 * just in case the clock is already
	 * sending timecodes
	 */
	true_send(peer, "\03\r");

	true_doevent(peer, e_Init);

	return true;
}


/*
 * true_receive - receive data from the serial interface on a clock
 */
static void
true_receive(
	struct recvbuf *rbufp
	)
{
	struct true_unit *up;
	struct refclockproc *pp;
	struct peer *peer;
	char synced;
	int i;
	/* These variables hold data until we decide to keep it */
	char	rd_lastcode[BMAX];
	l_fp	rd_tmp;
	unsigned short	rd_lencode;

	/*
	 * Get the clock this applies to and pointers to the data.
	 */
	peer = rbufp->recv_peer;
	pp = peer->procptr;
	up = pp->unitptr;

	/*
	 * Read clock output.  Automatically handles CLKLDISC.
	 */
	rd_lencode = (unsigned short)refclock_gtlin(rbufp, rd_lastcode, BMAX, &rd_tmp);
	rd_lastcode[rd_lencode] = '\0';

	/*
	 * There is a case where <cr><lf> generates 2 timestamps.
	 */
	if (rd_lencode == 0) {
		return;
}
	pp->lencode = rd_lencode;
	strlcpy(pp->a_lastcode, rd_lastcode, sizeof(pp->a_lastcode));
	pp->lastrec = rd_tmp;
	true_debug(peer, "receive(%s) [%d]\n", pp->a_lastcode,
		   pp->lencode);

	up->pollcnt = 2;
	record_clock_stats(peer, pp->a_lastcode);

	/*
	 * We get down to business, check the timecode format and decode
	 * its contents. This code decodes a multitude of different
	 * clock messages. Timecodes are processed if needed. All replies
	 * will be run through the state machine to tweak driver options
	 * and program the clock.
	 */

	/*
	 * Clock misunderstood our last command?
	 */
	if (pp->a_lastcode[0] == '?' ||
	    strcmp(pp->a_lastcode, "ERROR 05 NO SUCH FUNCTION") == 0) {
		true_doevent(peer, e_Huh);
		return;
	}

	/*
	 * Timecode: "Fnn"
	 * (from TM/TMD clock when it wants to tell us what it's up to.)
	 */
	if (sscanf(pp->a_lastcode, "F%2d", &i) == 1 && i > 0 && i < 80) {
		switch (i) {
		case 50:
			true_doevent(peer, e_F50);
			break;
		case 51:
			true_doevent(peer, e_F51);
			break;
		default:
			true_debug(peer, "got F%02d - ignoring\n", i);
			break;
		}
		return;
	}

	/*
	 * Timecode: " TRUETIME Mk III" or " TRUETIME XL"
	 * (from a TM/TMD/XL clock during initialization.)
	 */
	if (strncmp(pp->a_lastcode, " TRUETIME Mk III ", 17) == 0 ||
	    strncmp(pp->a_lastcode, " TRUETIME XL", 12) == 0) {
		true_doevent(peer, e_F18);
		NLOG(NLOG_CLOCKSTATUS) {
			msyslog(LOG_INFO, "REFCLOCK: TM/TMD/XL: %s", pp->a_lastcode);
		}
		return;
	}

	/*
	 * Timecode: "N03726428W12209421+000033"
	 *			1	   2
	 * index      0123456789012345678901234
	 * (from a TCU during initialization)
	 */
	if ((pp->a_lastcode[0] == 'N' || pp->a_lastcode[0] == 'S') &&
	    (pp->a_lastcode[9] == 'W' || pp->a_lastcode[9] == 'E') &&
	    pp->a_lastcode[18] == '+') {
		true_doevent(peer, e_Location);
		NLOG(NLOG_CLOCKSTATUS) {
			msyslog(LOG_INFO, "REFCLOCK: TCU-800: %s", pp->a_lastcode);
		}
		return;
	}
	/*
	 * Timecode: "ddd:hh:mm:ssQ"
	 *			1	   2
	 * index      0123456789012345678901234
	 * (from all clocks supported by this driver.)
	 */
	if (pp->a_lastcode[3] == ':' &&
	    pp->a_lastcode[6] == ':' &&
	    pp->a_lastcode[9] == ':' &&
	    sscanf(pp->a_lastcode, "%3d:%2d:%2d:%2d%c",
		   &pp->day, &pp->hour, &pp->minute,
		   &pp->second, &synced) == 5) {

		/*
		 * Adjust the synchronize indicator according to timecode
		 * say were OK, and then say not if we really are not OK
		 */
		if (synced == '>' || synced == '#' || synced == '?'
		    || synced == 'X')
			pp->leap = LEAP_NOTINSYNC;
		else
			pp->leap = LEAP_NOWARNING;

		true_doevent(peer, e_TS);

#ifdef ENABLE_PPS720
		/* If it's taken more than 65ms to get here, we'll lose. */
		if ((pp->sloppyclockflag & CLK_FLAG4) && up->pcl720init) {
			l_fp   off;

#ifdef CLOCK_PPS
			uint32_t sec;
			/*
			 * find out what time it really is. Include
			 * the count from the PCL720
			 */
			if (!clocktime(pp->year, pp->day, pp->hour, pp->minute,
				       pp->second, lfpuint(pp->lastrec),
				       &pp->yearstart, &sec)) {
				refclock_report(peer, CEVNT_BADTIME);
				return;
			}
			off = lfpinut(sec, 0);
#endif

			pp->usec = true_sample720();
#ifdef CLOCK_PPS
			TVUTOTSF(pp->usec, lfpfrac(off));
#endif

			/*
			 * Stomp all over the timestamp that was pulled out
			 * of the input stream. It's irrelevant since we've
			 * adjusted the input time to reflect now (via pp->usec)
			 * rather than when the data was collected.
			 */
			get_systime(&pp->lastrec);
#ifdef CLOCK_PPS
			/*
			 * Create a true offset for feeding to pps_sample()
			 */
			off -= pp->lastrec;

			pps_sample(peer, &off);
#endif
			true_debug(peer, "true_sample720: %luus\n", pp->usec);
		}
#endif

		/*
		 * The clock will blurt a timecode every second but we only
		 * want one when polled.  If we haven't been polled, bail out.
		 */
		if (!up->polled)
			return;

		if (!refclock_process(pp)) {
			refclock_report(peer, CEVNT_BADTIME);
			return;
		}
		/*
		 * If clock is good we send a NOMINAL message so that
		 * any previous BAD messages are nullified
		 */
		pp->lastref = pp->lastrec;
		refclock_receive(peer);
		refclock_report(peer, CEVNT_NOMINAL);

		/*
		 * We have succeeded in answering the poll.
		 * Turn off the flag and return
		 */
		up->polled = false;

		return;
	}

	/*
	 * No match to known timecodes, report failure and return
	 */
	refclock_report(peer, CEVNT_BADREPLY);
	return;
}


/*
 * true_send - time to send the clock a signal to cough up a time sample
 */
static void
true_send(
	struct peer *peer,
	const char *cmd
	)
{
	struct refclockproc *pp;

	pp = peer->procptr;
	if (!(pp->sloppyclockflag & CLK_FLAG1)) {
                ssize_t ret;
		size_t len = strlen(cmd);

		true_debug(peer, "Send '%s'\n", cmd);
		ret = write(pp->io.fd, cmd, len);
		if (ret < 0 || (size_t)ret != len)
			refclock_report(peer, CEVNT_FAULT);
		else
			pp->polls++;
	}
}


/*
 * state machine for initializing and controlling a clock
 */
static void
true_doevent(
	struct peer *peer,
	enum true_event event
	)
{
	struct true_unit *up;
	struct refclockproc *pp;

	pp = peer->procptr;
	up = pp->unitptr;
	if (event != e_TS) {
		NLOG(NLOG_CLOCKSTATUS) {
			msyslog(LOG_INFO, "REFCLOCK: TRUETIME: clock %s, state %s, event %s",
				typeStr(up->type),
				stateStr(up->state),
				eventStr(event));
		}
	}
	true_debug(peer, "clock %s, state %s, event %s\n",
		   typeStr(up->type), stateStr(up->state), eventStr(event));
	switch (up->type) {
	case t_tm:
		switch (event) {
		case e_Init:
			true_send(peer, "F18\r");
			up->state = s_Init;
			break;
		case e_F18:
			true_send(peer, "F50\r");
                        /*
                         * Timecode: " TRUETIME Mk III" or " TRUETIME XL"
                         * (from a TM/TMD/XL clock during initialization.)
                         */
                        if ( strcmp(pp->a_lastcode, " TRUETIME Mk III") == 0 ||
                            strncmp(pp->a_lastcode, " TRUETIME XL", 12) == 0) {
                                true_doevent(peer, e_F18);
                                NLOG(NLOG_CLOCKSTATUS) {
                                    msyslog(LOG_INFO, "REFCLOCK: TM/TMD/XL: %s",
                                            pp->a_lastcode);
                                }
                                return;
                        }
			up->state = s_F18;
			break;
		case e_F50:
			true_send(peer, "F51\r");
			up->state = s_F50;
			break;
		case e_F51:
			true_send(peer, "F08\r");
			up->state = s_Start;
			break;
		case e_TS:
			if (up->state != s_Start && up->state != s_Auto) {
				true_send(peer, "\03\r");
				break;
			}
			up->state = s_Auto;
			break;
		default:
			break;
		}
		break;
	case t_tcu:
		switch (event) {
		case e_Init:
			true_send(peer, "MD3\r");	/* GPS Synch'd Gen. */
			true_send(peer, "TSU\r");	/* UTC, not GPS. */
			true_send(peer, "AU\r");	/* Auto Timestamps. */
			up->state = s_Start;
			break;
		case e_TS:
			if (up->state != s_Start && up->state != s_Auto) {
				true_send(peer, "\03\r");
				break;
			}
			up->state = s_Auto;
			break;
		default:
			break;
		}
		break;
	case t_tl3:
                switch (event) {
                    case e_Init:
                        true_send(peer, "ST1"); /* Turn on continuous stream */
                        break;
                    case e_TS:
                        up->state = s_Auto;
                        break;
                    default:
                        break;
                }
                break;
	case t_unknown:
		switch (up->state) {
		case s_Base:
			if (event != e_Init) {
			    abort();
			}
			true_send(peer, "P\r");
			up->state = s_InqGOES;
			break;
		case s_InqGOES:
			switch (event) {
			case e_Init:	/*FALLTHROUGH*/
			case e_Huh:
                                sleep(1);               /* wait for it */
                                break;
                        default:
                                abort();
                        }
                        break;
		case s_InqTM:
			switch (event) {
			case e_F18:
				up->type = t_tm;
				true_doevent(peer, e_Init);
				break;
			case e_Init:	/*FALLTHROUGH*/
			case e_Huh:
				true_send(peer, "PO\r");
				up->state = s_InqTCU;
				break;
			default:
                                msyslog(LOG_INFO,
                                        "REFCLOCK: TRUETIME: TM/TMD init fellthrough!");
			        break;
			}
			break;
		case s_InqTCU:
			switch (event) {
			case e_Location:
				up->type = t_tcu;
				true_doevent(peer, e_Init);
				break;
			case e_Init:	/*FALLTHROUGH*/
			case e_Huh:
				up->state = s_Base;
				sleep(1);	/* XXX */
				break;
			default:
                                msyslog(LOG_INFO,
                                        "REFCLOCK: TRUETIME: TCU init fellthrough!");
                                break;
			}
			break;
			/*
			 * An expedient hack to prevent lint complaints,
			 * these don't actually need to be used here...
			 */
		case s_Init:
		case s_F18:
		case s_F50:
		case s_Start:
		case s_Auto:
		case s_Max:
			msyslog(LOG_INFO, "REFCLOCK: TRUETIME: state %s is unexpected!",
				stateStr(up->state));
		default:
			/* huh? */
			break;
		}
		break;
	default:
                msyslog(LOG_INFO, "REFCLOCK: TRUETIME: cannot identify refclock!");
		abort();
		/* NOTREACHED */
	}

#ifdef ENABLE_PPS720
	if ((pp->sloppyclockflag & CLK_FLAG4) && !up->pcl720init) {
		/* Make counter trigger on gate0, count down from 65535. */
		pcl720_load(PCL720_IOB, PCL720_CTR, i8253_oneshot, 65535);
		/*
		 * (These constants are OK since
		 * they represent hardware maximums.)
		 */
		NLOG(NLOG_CLOCKINFO) {
			msyslog(LOG_NOTICE, "REFCLOCK: PCL-720 initialized");
		}
		up->pcl720init++;
	}
#endif


}

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

	UNUSED_ARG(unit);

	/*
	 * You don't need to poll this clock.  It puts out timecodes
	 * once per second.  If asked for a timestamp, take note.
	 * The next time a timecode comes in, it will be fed back.
	 */
	pp = peer->procptr;
	up = pp->unitptr;
	if (up->pollcnt > 0) {
		up->pollcnt--;
	} else {
		true_doevent(peer, e_Init);
		refclock_report(peer, CEVNT_TIMEOUT);
	}

	/*
	 * polled every 64 seconds. Ask true_receive to hand in a
	 * timestamp.
	 */
	up->polled = true;
	pp->polls++;
}

#ifdef ENABLE_PPS720
/*
 * true_sample720 - sample the PCL-720
 */
static unsigned long
true_sample720(void)
{
	unsigned long f;

	/* We wire the PCL-720's 8253.OUT0 to bit 0 of connector 3.
	 * If it is not being held low now, we did not get called
	 * within 65535us.
	 */
	if (inb(pcl720_data_16_23(PCL720_IOB)) & 0x01) {
		NLOG(NLOG_CLOCKINFO) {
			msyslog(LOG_NOTICE, "REFCLOCK: PCL-720 out of synch");
		}
		return (0);
	}
	f = (65536 - pcl720_read(PCL720_IOB, PCL720_CTR));
#ifdef DEBUG_PPS720
	msyslog(LOG_DEBUG, "REFCLOCK: PCL-720: %luus", f);
#endif
	return (f);
}
#endif

