/*

 * refclock_heath - clock driver for Heath GC-1000

 * (but no longer the GC-1001 Model II, which apparently never worked)

 */

#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#if defined(REFCLOCK) && defined(CLOCK_HEATH)

#include "ntpd.h"

#include "ntp_io.h"

#include "ntp_refclock.h"

#include "ntp_stdlib.h"

#include <stdio.h>

#include <ctype.h>

#ifdef HAVE_SYS_IOCTL_H

# include <sys/ioctl.h>

#endif /* not HAVE_SYS_IOCTL_H */

/*

 * This driver supports the Heath GC-1000 Most Accurate Clock, with

 * RS232C Output Accessory. This is a WWV/WWVH receiver somewhat less

 * robust than other supported receivers. Its claimed accuracy is 100 ms

 * when actually synchronized to the broadcast signal, but this doesn't

 * happen even most of the time, due to propagation conditions, ambient

 * noise sources, etc. When not synchronized, the accuracy is at the

 * whim of the internal clock oscillator, which can wander into the

 * sunset without warning. Since the indicated precision is 100 ms,

 * expect a host synchronized only to this thing to wander to and fro,

 * occasionally being rudely stepped when the offset exceeds the default

 * clock_max of 128 ms. 

 *

 * There were two GC-1000 versions supported by this driver. The original

 * GC-1000 with RS-232 output first appeared in 1983, but dissapeared

 * from the market a few years later. The GC-1001 II with RS-232 output

 * first appeared circa 1990, but apparently is no longer manufactured.

 * The two models differ considerably, both in interface and commands.

 * The GC-1000 has a pseudo-bipolar timecode output triggered by a RTS

 * transition. The timecode includes both the day of year and time of

 * day. The GC-1001 II has a true bipolar output and a complement of

 * single character commands. The timecode includes only the time of

 * day.

 *

 * The GC-1001 II was apparently never tested and, based on a Coverity

 * scan, apparently never worked [Bug 689].  Related code has been disabled.

 *

 * GC-1000

 *

 * The internal DIPswitches should be set to operate in MANUAL mode. The

 * external DIPswitches should be set to GMT and 24-hour format.

 *

 * In MANUAL mode the clock responds to a rising edge of the request to

 * send (RTS) modem control line by sending the timecode. Therefore, it

 * is necessary that the operating system implement the TIOCMBIC and

 * TIOCMBIS ioctl system calls and TIOCM_RTS control bit. Present

 * restrictions require the use of a POSIX-compatible programming

 * interface, although other interfaces may work as well.

 *

 * A simple hardware modification to the clock can be made which

 * prevents the clock hearing the request to send (RTS) if the HI SPEC

 * lamp is out. Route the HISPEC signal to the tone decoder board pin

 * 19, from the display, pin 19. Isolate pin 19 of the decoder board

 * first, but maintain connection with pin 10. Also isolate pin 38 of

 * the CPU on the tone board, and use half an added 7400 to gate the

 * original signal to pin 38 with that from pin 19.

 *

 * The clock message consists of 23 ASCII printing characters in the

 * following format:

 *

 * hh:mm:ss.f AM  dd/mm/yr<cr>

 *

 *  hh:mm:ss.f = hours, minutes, seconds

 *  f = deciseconds ('?' when out of spec)

 *  AM/PM/bb = blank in 24-hour mode

 *  dd/mm/yr = day, month, year

 *

 * The alarm condition is indicated by '?', rather than a digit, at f.

 * Note that 0?:??:??.? is displayed before synchronization is first

 * established and hh:mm:ss.? once synchronization is established and

 * then lost again for about a day.

 *

 * GC-1001 II

 *

 * Commands consist of a single letter and are case sensitive. When

 * enterred in lower case, a description of the action performed is

 * displayed. When enterred in upper case the action is performed.

 * Following is a summary of descriptions as displayed by the clock:

 *

 * The clock responds with a command The 'A' command returns an ASCII

 * local time string:  HH:MM:SS.T xx<CR>, where

 *

 *  HH = hours

 *  MM = minutes

 *  SS = seconds

 *  T = tenths-of-seconds

 *  xx = 'AM', 'PM', or '  '

 *  <CR> = carriage return

 *

 * The 'D' command returns 24 pairs of bytes containing the variable

 * divisor value at the end of each of the previous 24 hours. This

 * allows the timebase trimming process to be observed.  UTC hour 00 is

 * always returned first. The first byte of each pair is the high byte

 * of (variable divisor * 16); the second byte is the low byte of

 * (variable divisor * 16). For example, the byte pair 3C 10 would be

 * returned for a divisor of 03C1 hex (961 decimal).

 *

 * The 'I' command returns:  | TH | TL | ER | DH | DL | U1 | I1 | I2 | ,

 * where

 *

 *  TH = minutes since timebase last trimmed (high byte)

 *  TL = minutes since timebase last trimmed (low byte)

 *  ER = last accumulated error in 1.25 ms increments

 *  DH = high byte of (current variable divisor * 16)

 *  DL = low byte of (current variable divisor * 16)

 *  U1 = UT1 offset (/.1 s):  | + | 4 | 2 | 1 | 0 | 0 | 0 | 0 |

 *  I1 = information byte 1:  | W | C | D | I | U | T | Z | 1 | ,

 *       where

 *

 *    W = set by WWV(H)

 *    C = CAPTURE LED on

 *    D = TRIM DN LED on

 *    I = HI SPEC LED on

 *    U = TRIM UP LED on

 *    T = DST switch on

 *    Z = UTC switch on

 *    1 = UT1 switch on

 *

 *  I2 = information byte 2:  | 8 | 8 | 4 | 2 | 1 | D | d | S | ,

 *       where

 *

 *    8, 8, 4, 2, 1 = TIME ZONE switch settings

 *    D = DST bit (#55) in last-received frame

 *    d = DST bit (#2) in last-received frame

 *    S = clock is in simulation mode

 *

 * The 'P' command returns 24 bytes containing the number of frames

 * received without error during UTC hours 00 through 23, providing an

 * indication of hourly propagation.  These bytes are updated each hour

 * to reflect the previous 24 hour period.  UTC hour 00 is always

 * returned first.

 *

 * The 'T' command returns the UTC time:  | HH | MM | SS | T0 | , where

 *  HH = tens-of-hours and hours (packed BCD)

 *  MM = tens-of-minutes and minutes (packed BCD)

 *  SS = tens-of-seconds and seconds (packed BCD)

 *  T = tenths-of-seconds (BCD)

 *

 * Fudge Factors

 *

 * A fudge time1 value of .04 s appears to center the clock offset

 * residuals. The fudge time2 parameter is the local time offset east of

 * Greenwich, which depends on DST. Sorry about that, but the clock

 * gives no hint on what the DIPswitches say.

 */

/*

 * Interface definitions

 */

#define DEVICE    "/dev/heath%d" /* device name and unit */

#define PRECISION (-4)  /* precision assumed (about 100 ms) */

#define REFID   "WWV\0"  /* reference ID */

#define DESCRIPTION "Heath GC-1000 Most Accurate Clock" /* WRU */

#define LENHEATH1 23  /* min timecode length */

#if 0 /* BUG 689 */

#define LENHEATH2 13  /* min timecode length */

#endif

/*

 * Tables to compute the ddd of year form icky dd/mm timecode. Viva la

 * leap.

 */

static int day1tab[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

static int day2tab[] = {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

/*

 * Baud rate table. The GC-1000 supports 1200, 2400 and 4800; the

 * GC-1001 II supports only 9600.

 */

static int speed[] = {B1200, B2400, B4800, B9600};

/*

 * Function prototypes

 */

static  int heath_start (int, struct peer *);

static  void  heath_shutdown  (int, struct peer *);

static  void  heath_receive (struct recvbuf *);

static  void  heath_poll  (int, struct peer *);

/*

 * Transfer vector

 */

struct  refclock refclock_heath = {

  heath_start,    /* start up driver */

  heath_shutdown,   /* shut down driver */

  heath_poll,   /* transmit poll message */

  noentry,    /* not used (old heath_control) */

  noentry,    /* initialize driver */

  noentry,    /* not used (old heath_buginfo) */

  NOFLAGS     /* not used */

};

/*

 * heath_start - open the devices and initialize data for processing

 */

static int

heath_start(

  int unit,

  struct peer *peer

  )

{

  struct refclockproc *pp;

  int fd;

  char device[20];

  /*

   * Open serial port

   */

  snprintf(device, sizeof(device), DEVICE, unit);

  fd = refclock_open(device, speed[peer->ttl & 0x3],

         LDISC_REMOTE);

  if (fd <= 0)

    return (0);

  pp = peer->procptr;

  pp->io.clock_recv = heath_receive;

  pp->io.srcclock = peer;

  pp->io.datalen = 0;

  pp->io.fd = fd;

  if (!io_addclock(&pp->io)) {

    close(fd);

    pp->io.fd = -1;

    return (0);

  }

  /*

   * Initialize miscellaneous variables

   */

  peer->precision = PRECISION;

  pp->clockdesc = DESCRIPTION;

  memcpy(&pp->refid, REFID, 4);

  return (1);

}

/*

 * heath_shutdown - shut down the clock

 */

static void

heath_shutdown(

  int unit,

  struct peer *peer

  )

{

  struct refclockproc *pp;

  pp = peer->procptr;

  if (-1 != pp->io.fd)

    io_closeclock(&pp->io);

}

/*

 * heath_receive - receive data from the serial interface

 */

static void

heath_receive(

  struct recvbuf *rbufp

  )

{

  struct refclockproc *pp;

  struct peer *peer;

  l_fp trtmp;

  int month, day;

  int i;

  char dsec, a[5];

  /*

   * Initialize pointers and read the timecode and timestamp

   */

  peer = rbufp->recv_peer;

  pp = peer->procptr;

  pp->lencode = refclock_gtlin(rbufp, pp->a_lastcode, BMAX,

      &trtmp);

  /*

   * 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.

   */

  switch (pp->lencode) {

  /*

   * GC-1000 timecode format: "hh:mm:ss.f AM  mm/dd/yy"

   * GC-1001 II timecode format: "hh:mm:ss.f   "

   */

  case LENHEATH1:

    if (sscanf(pp->a_lastcode,

        "%2d:%2d:%2d.%c%5c%2d/%2d/%2d", &pp->hour,

        &pp->minute, &pp->second, &dsec, a, &month, &day,

        &pp->year) != 8) {

      refclock_report(peer, CEVNT_BADREPLY);

      return;

    }

    break;

#if 0 /* BUG 689 */

  /*

   * GC-1001 II timecode format: "hh:mm:ss.f   "

   */

  case LENHEATH2:

    if (sscanf(pp->a_lastcode, "%2d:%2d:%2d.%c", &pp->hour,

        &pp->minute, &pp->second, &dsec) != 4) {

      refclock_report(peer, CEVNT_BADREPLY);

      return;

    } else {

      struct tm *tm_time_p;

      time_t     now;

      time(&now); /* we should grab 'now' earlier */

      tm_time_p = gmtime(&now);

      /*

       * There is a window of time around midnight

       * where this will Do The Wrong Thing.

       */

      if (tm_time_p) {

        month = tm_time_p->tm_mon + 1;

        day = tm_time_p->tm_mday;

      } else {

        refclock_report(peer, CEVNT_FAULT);

        return;

      }

    }

    break;

#endif

  default:

    refclock_report(peer, CEVNT_BADREPLY);

    return;

  }

  /*

   * We determine the day of the year from the DIPswitches. This

   * should be fixed, since somebody might forget to set them.

   * Someday this hazard will be fixed by a fiendish scheme that

   * looks at the timecode and year the radio shows, then computes

   * the residue of the seconds mod the seconds in a leap cycle.

   * If in the third year of that cycle and the third and later

   * months of that year, add one to the day. Then, correct the

   * timecode accordingly. Icky pooh. This bit of nonsense could

   * be avoided if the engineers had been required to write a

   * device driver before finalizing the timecode format.

   */

  if (month < 1 || month > 12 || day < 1) {

    refclock_report(peer, CEVNT_BADTIME);

    return;

  }

  if (pp->year % 4) {

    if (day > day1tab[month - 1]) {

      refclock_report(peer, CEVNT_BADTIME);

      return;

    }

    for (i = 0; i < month - 1; i++)

        day += day1tab[i];

  } else {

    if (day > day2tab[month - 1]) {

      refclock_report(peer, CEVNT_BADTIME);

      return;

    }

    for (i = 0; i < month - 1; i++)

        day += day2tab[i];

  }

  pp->day = day;

  /*

   * Determine synchronization and last update

   */

  if (!isdigit((unsigned char)dsec))

    pp->leap = LEAP_NOTINSYNC;

  else {

    pp->nsec = (dsec - '0') * 100000000;

    pp->leap = LEAP_NOWARNING;

  }

  if (!refclock_process(pp))

    refclock_report(peer, CEVNT_BADTIME);

}

/*

 * heath_poll - called by the transmit procedure

 */

static void

heath_poll(

  int unit,

  struct peer *peer

  )

{

  struct refclockproc *pp;

  int bits = TIOCM_RTS;

  /*

   * At each poll we check for timeout and toggle the RTS modem

   * control line, then take a timestamp. Presumably, this is the

   * event the radio captures to generate the timecode.

   * Apparently, the radio takes about a second to make up its

   * mind to send a timecode, so the receive timestamp is

   * worthless.

   */

  pp = peer->procptr;

  /*

   * We toggle the RTS modem control lead (GC-1000) and sent a T

   * (GC-1001 II) to kick a timecode loose from the radio. This

   * code works only for POSIX and SYSV interfaces. With bsd you

   * are on your own. We take a timestamp between the up and down

   * edges to lengthen the pulse, which should be about 50 usec on

   * a Sun IPC. With hotshot CPUs, the pulse might get too short.

   * Later.

   *

   * Bug 689: Even though we no longer support the GC-1001 II,

   * I'm leaving the 'T' write in for timing purposes.

   */

  if (ioctl(pp->io.fd, TIOCMBIC, (char *)&bits) < 0)

    refclock_report(peer, CEVNT_FAULT);

  get_systime(&pp->lastrec);

  if (write(pp->io.fd, "T", 1) != 1)

    refclock_report(peer, CEVNT_FAULT);

  ioctl(pp->io.fd, TIOCMBIS, (char *)&bits);

  if (pp->coderecv == pp->codeproc) {

    refclock_report(peer, CEVNT_TIMEOUT);

    return;

  }

  pp->lastref = pp->lastrec;

  refclock_receive(peer);

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

#ifdef DEBUG

  if (debug)

      printf("heath: timecode %d %s\n", pp->lencode,

       pp->a_lastcode);

#endif

  pp->polls++;

}

#else

int refclock_heath_bs;

#endif /* REFCLOCK */