2 ** refclock_datum - clock driver for the Datum Programmable Time Server
4 ** Important note: This driver assumes that you have termios. If you have
5 ** a system that does not have termios, you will have to modify this driver.
7 ** Sorry, I have only tested this driver on SUN and HP platforms.
14 #if defined(REFCLOCK) && defined(CLOCK_DATUM)
22 #include "ntp_refclock.h"
23 #include "ntp_unixtime.h"
24 #include "ntp_stdlib.h"
29 #if defined(HAVE_BSD_TTYS)
31 #endif /* HAVE_BSD_TTYS */
33 #if defined(HAVE_SYSV_TTYS)
35 #endif /* HAVE_SYSV_TTYS */
37 #if defined(HAVE_TERMIOS)
43 #include <sys/clkdefs.h>
47 #include "ntp_stdlib.h"
50 ** This driver supports the Datum Programmable Time System (PTS) clock.
51 ** The clock works in very straight forward manner. When it receives a
52 ** time code request (e.g., the ascii string "//k/mn"), it responds with
53 ** a seven byte BCD time code. This clock only responds with a
54 ** time code after it first receives the "//k/mn" message. It does not
55 ** periodically send time codes back at some rate once it is started.
56 ** the returned time code can be broken down into the following fields.
58 ** _______________________________
59 ** Bit Index | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
60 ** ===============================
61 ** byte 0: | - - - - | H D |
62 ** ===============================
63 ** byte 1: | T D | U D |
64 ** ===============================
65 ** byte 2: | - - | T H | U H |
66 ** ===============================
67 ** byte 3: | - | T M | U M |
68 ** ===============================
69 ** byte 4: | - | T S | U S |
70 ** ===============================
71 ** byte 5: | t S | h S |
72 ** ===============================
73 ** byte 6: | m S | - - - - |
74 ** ===============================
76 ** In the table above:
78 ** "-" means don't care
79 ** "H D", "T D", and "U D" means Hundreds, Tens, and Units of Days
80 ** "T H", and "UH" means Tens and Units of Hours
81 ** "T M", and "U M" means Tens and Units of Minutes
82 ** "T S", and "U S" means Tens and Units of Seconds
83 ** "t S", "h S", and "m S" means tenths, hundredths, and thousandths
86 ** The Datum PTS communicates throught the RS232 port on your machine.
87 ** Right now, it assumes that you have termios. This driver has been tested
88 ** on SUN and HP workstations. The Datum PTS supports various IRIG and
89 ** NASA input codes. This driver assumes that the name of the device is
90 ** /dev/datum. You will need to make a soft link to your RS232 device or
91 ** create a new driver to use this refclock.
99 ** Note that if GMT is defined, then the Datum PTS must use Greenwich
100 ** time. Otherwise, this driver allows the Datum PTS to use the current
101 ** wall clock for its time. It determines the time zone offset by minimizing
102 ** the error after trying several time zone offsets. If the Datum PTS
103 ** time is Greenwich time and GMT is not defined, everything should still
104 ** work since the time zone will be found to be 0. What this really means
105 ** is that your system time (at least to start with) must be within the
106 ** correct time by less than +- 30 minutes. The default is for GMT to not
107 ** defined. If you really want to force GMT without the funny +- 30 minute
108 ** stuff then you must define (uncomment) GMT below.
113 #define DEBUG_DATUM_PTC
114 #define LOG_TIME_ERRORS
118 #define PRECISION (-10) /* precision assumed 1/1024 ms */
119 #define REFID "DATM" /* reference id */
120 #define DATUM_DISPERSION 0 /* fixed dispersion = 0 ms */
121 #define DATUM_MAX_ERROR 0.100 /* limits on sigma squared */
123 #define DATUM_MAX_ERROR2 (DATUM_MAX_ERROR*DATUM_MAX_ERROR)
126 ** The Datum PTS structure
130 ** I don't use a fixed array of MAXUNITS like everyone else just because
131 ** I don't like to program that way. Sorry if this bothers anyone. I assume
132 ** that you can use any id for your unit and I will search for it in a
133 ** dynamic array of units until I find it. I was worried that users might
134 ** enter a bad id in their configuration file (larger than MAXUNITS) and
135 ** besides, it is just cleaner not to have to assume that you have a fixed
136 ** number of anything in a program.
139 struct datum_pts_unit {
140 struct peer *peer; /* peer used by ntp */
141 struct refclockio io; /* io structure used by ntp */
142 int PTS_fd; /* file descriptor for PTS */
143 u_int unit; /* id for unit */
144 u_long timestarted; /* time started */
145 l_fp lastrec; /* time tag for the receive time (system) */
146 l_fp lastref; /* reference time (Datum time) */
147 u_long yearstart; /* the year that this clock started */
148 int coderecv; /* number of time codes received */
151 int minute; /* minutes */
152 int second; /* seconds */
153 int msec; /* miliseconds */
154 int usec; /* miliseconds */
155 u_char leap; /* funny leap character code */
156 char retbuf[8]; /* returned time from the datum pts */
157 char nbytes; /* number of bytes received from datum pts */
158 double sigma2; /* average squared error (roughly) */
159 int tzoff; /* time zone offest from GMT */
163 ** PTS static constant variables for internal use
166 static char TIME_REQUEST[6]; /* request message sent to datum for time */
167 static int nunits; /* number of active units */
168 static struct datum_pts_unit
169 **datum_pts_unit; /* dynamic array of datum PTS structures */
172 ** Callback function prototypes that ntpd needs to know about.
175 static int datum_pts_start P((int, struct peer *));
176 static void datum_pts_shutdown P((int, struct peer *));
177 static void datum_pts_poll P((int, struct peer *));
178 static void datum_pts_control P((int, struct refclockstat *,
179 struct refclockstat *, struct peer *));
180 static void datum_pts_init P((void));
181 static void datum_pts_buginfo P((int, struct refclockbug *, struct peer *));
184 ** This is the call back function structure that ntpd actually uses for
188 struct refclock refclock_datum = {
189 datum_pts_start, /* start up a new Datum refclock */
190 datum_pts_shutdown, /* shutdown a Datum refclock */
191 datum_pts_poll, /* sends out the time request */
192 datum_pts_control, /* not used */
193 datum_pts_init, /* initialization (called first) */
194 datum_pts_buginfo, /* not used */
195 NOFLAGS /* we are not setting any special flags */
199 ** The datum_pts_receive callback function is handled differently from the
200 ** rest. It is passed to the ntpd io data structure. Basically, every
201 ** 64 seconds, the datum_pts_poll() routine is called. It sends out the time
202 ** request message to the Datum Programmable Time System. Then, ntpd
203 ** waits on a select() call to receive data back. The datum_pts_receive()
204 ** function is called as data comes back. We expect a seven byte time
205 ** code to be returned but the datum_pts_receive() function may only get
206 ** a few bytes passed to it at a time. In other words, this routine may
207 ** get called by the io stuff in ntpd a few times before we get all seven
208 ** bytes. Once the last byte is received, we process it and then pass the
209 ** new time measurement to ntpd for updating the system time. For now,
210 ** there is no 3 state filtering done on the time measurements. The
211 ** jitter may be a little high but at least for its current use, it is not
212 ** a problem. We have tried to keep things as simple as possible. This
213 ** clock should not jitter more than 1 or 2 mseconds at the most once
214 ** things settle down. It is important to get the right drift calibrated
215 ** in the ntpd.drift file as well as getting the right tick set up right
216 ** using tickadj for SUNs. Tickadj is not used for the HP but you need to
217 ** remember to bring up the adjtime daemon because HP does not support
218 ** the adjtime() call.
221 static void datum_pts_receive P((struct recvbuf *));
223 /*......................................................................*/
224 /* datum_pts_start - start up the datum PTS. This means open the */
225 /* RS232 device and set up the data structure for my unit. */
226 /*......................................................................*/
234 struct datum_pts_unit **temp_datum_pts_unit;
235 struct datum_pts_unit *datum_pts;
240 #ifdef DEBUG_DATUM_PTC
242 printf("Starting Datum PTS unit %d\n", unit);
246 ** Create the memory for the new unit
249 temp_datum_pts_unit = (struct datum_pts_unit **)
250 malloc((nunits+1)*sizeof(struct datum_pts_unit *));
251 if (nunits > 0) memcpy(temp_datum_pts_unit, datum_pts_unit,
252 nunits*sizeof(struct datum_pts_unit *));
253 free(datum_pts_unit);
254 datum_pts_unit = temp_datum_pts_unit;
255 datum_pts_unit[nunits] = (struct datum_pts_unit *)
256 malloc(sizeof(struct datum_pts_unit));
257 datum_pts = datum_pts_unit[nunits];
259 datum_pts->unit = unit; /* set my unit id */
260 datum_pts->yearstart = 0; /* initialize the yearstart to 0 */
261 datum_pts->sigma2 = 0.0; /* initialize the sigma2 to 0 */
264 ** Open the Datum PTS device
267 datum_pts->PTS_fd = open("/dev/datum",O_RDWR);
269 fcntl(datum_pts->PTS_fd, F_SETFL, 0); /* clear the descriptor flags */
271 #ifdef DEBUG_DATUM_PTC
273 printf("Opening RS232 port with file descriptor %d\n",
278 ** Set up the RS232 terminal device information. Note that we assume that
279 ** we have termios. This code has only been tested on SUNs and HPs. If your
280 ** machine does not have termios this driver cannot be initialized. You can change this
281 ** if you want by editing this source. Please give the changes back to the
282 ** ntp folks so that it can become part of their regular distribution.
287 arg.c_iflag = IGNBRK;
289 arg.c_cflag = B9600 | CS8 | CREAD | PARENB | CLOCAL;
291 arg.c_cc[VMIN] = 0; /* start timeout timer right away (not used) */
292 arg.c_cc[VTIME] = 30; /* 3 second timout on reads (not used) */
294 tcsetattr(datum_pts->PTS_fd, TCSANOW, &arg);
298 msyslog(LOG_ERR, "Datum_PTS: Termios not supported in this driver");
299 (void)close(datum_pts->PTS_fd);
301 peer->precision = PRECISION;
302 pp->clockdesc = DESCRIPTION;
303 memcpy((char *)&pp->refid, REFID, 4);
310 ** Initialize the ntpd IO structure
313 datum_pts->peer = peer;
314 datum_pts->io.clock_recv = datum_pts_receive;
315 datum_pts->io.srcclock = (caddr_t)datum_pts;
316 datum_pts->io.datalen = 0;
317 datum_pts->io.fd = datum_pts->PTS_fd;
319 if (!io_addclock(&(datum_pts->io))) {
321 #ifdef DEBUG_DATUM_PTC
323 printf("Problem adding clock\n");
326 msyslog(LOG_ERR, "Datum_PTS: Problem adding clock");
327 (void)close(datum_pts->PTS_fd);
333 ** Now add one to the number of units and return a successful code
342 /*......................................................................*/
343 /* datum_pts_shutdown - this routine shuts doen the device and */
344 /* removes the memory for the unit. */
345 /*......................................................................*/
354 struct datum_pts_unit **temp_datum_pts_unit;
356 #ifdef DEBUG_DATUM_PTC
358 printf("Shutdown Datum PTS\n");
361 msyslog(LOG_ERR, "Datum_PTS: Shutdown Datum PTS");
364 ** First we have to find the right unit (i.e., the one with the same id).
365 ** We do this by looping through the dynamic array of units intil we find
366 ** it. Note, that I don't simply use an array with a maximimum number of
367 ** Datum PTS units. Everything is completely dynamic.
370 for (i=0; i<nunits; i++) {
371 if (datum_pts_unit[i]->unit == unit) {
374 ** We found the unit so close the file descriptor and free up the memory used
378 io_closeclock(&datum_pts_unit[i]->io);
379 close(datum_pts_unit[i]->PTS_fd);
380 free(datum_pts_unit[i]);
383 ** Now clean up the datum_pts_unit dynamic array so that there are no holes.
384 ** This may mean moving pointers around, etc., to keep things compact.
389 temp_datum_pts_unit = (struct datum_pts_unit **)
390 malloc((nunits-1)*sizeof(struct datum_pts_unit *));
391 if (i!= 0) memcpy(temp_datum_pts_unit, datum_pts_unit,
392 i*sizeof(struct datum_pts_unit *));
394 for (j=i+1; j<nunits; j++) {
395 temp_datum_pts_unit[j-1] = datum_pts_unit[j];
398 free(datum_pts_unit);
399 datum_pts_unit = temp_datum_pts_unit;
403 free(datum_pts_unit);
404 datum_pts_unit = NULL;
413 #ifdef DEBUG_DATUM_PTC
415 printf("Error, could not shut down unit %d\n",unit);
418 msyslog(LOG_ERR, "Datum_PTS: Could not shut down Datum PTS unit %d",unit);
422 /*......................................................................*/
423 /* datum_pts_poll - this routine sends out the time request to the */
424 /* Datum PTS device. The time will be passed back in the */
425 /* datum_pts_receive() routine. */
426 /*......................................................................*/
437 struct datum_pts_unit *datum_pts;
439 #ifdef DEBUG_DATUM_PTC
441 printf("Poll Datum PTS\n");
445 ** Find the right unit and send out a time request once it is found.
449 for (i=0; i<nunits; i++) {
450 if (datum_pts_unit[i]->unit == unit) {
452 datum_pts = datum_pts_unit[i];
453 error_code = write(datum_pts->PTS_fd, TIME_REQUEST, 6);
454 if (error_code != 6) perror("TIME_REQUEST");
455 datum_pts->nbytes = 0;
461 ** Print out an error message if we could not find the right unit.
464 if (unit_index == -1) {
466 #ifdef DEBUG_DATUM_PTC
468 printf("Error, could not poll unit %d\n",unit);
471 msyslog(LOG_ERR, "Datum_PTS: Could not poll unit %d",unit);
479 /*......................................................................*/
480 /* datum_pts_control - not used */
481 /*......................................................................*/
486 struct refclockstat *in,
487 struct refclockstat *out,
492 #ifdef DEBUG_DATUM_PTC
494 printf("Control Datum PTS\n");
500 /*......................................................................*/
501 /* datum_pts_init - initializes things for all possible Datum */
502 /* time code generators that might be used. In practice, this is */
503 /* only called once at the beginning before anything else is */
505 /*......................................................................*/
512 /*...... open up the log file if we are debugging ......................*/
516 ** Open up the log file if we are debugging. For now, send data out to the
520 #ifdef DEBUG_DATUM_PTC
522 printf("Init Datum PTS\n");
526 ** Initialize the time request command string. This is the only message
527 ** that we ever have to send to the Datum PTS (although others are defined).
530 memcpy(TIME_REQUEST, "//k/mn",6);
533 ** Initialize the number of units to 0 and set the dynamic array of units to
534 ** NULL since there are no units defined yet.
537 datum_pts_unit = NULL;
543 /*......................................................................*/
544 /* datum_pts_buginfo - not used */
545 /*......................................................................*/
550 register struct refclockbug *bug,
551 register struct peer *peer
555 #ifdef DEBUG_DATUM_PTC
557 printf("Buginfo Datum PTS\n");
563 /*......................................................................*/
564 /* datum_pts_receive - receive the time buffer that was read in */
565 /* by the ntpd io handling routines. When 7 bytes have been */
566 /* received (it may take several tries before all 7 bytes are */
567 /* received), then the time code must be unpacked and sent to */
568 /* the ntpd clock_receive() routine which causes the systems */
569 /* clock to be updated (several layers down). */
570 /*......................................................................*/
574 struct recvbuf *rbufp
579 struct datum_pts_unit *datum_pts;
584 double ftimerr, abserr;
585 #ifdef DEBUG_DATUM_PTC
592 ** Get the time code (maybe partial) message out of the rbufp buffer.
595 datum_pts = (struct datum_pts_unit *)rbufp->recv_srcclock;
596 dpt = (char *)&rbufp->recv_space;
597 dpend = rbufp->recv_length;
599 #ifdef DEBUG_DATUM_PTC
601 printf("Receive Datum PTS: %d bytes\n", dpend);
605 /*...... save the ntp system time when the first byte is received ......*/
609 ** Save the ntp system time when the first byte is received. Note that
610 ** because it may take several calls to this routine before all seven
611 ** bytes of our return message are finally received by the io handlers in
612 ** ntpd, we really do want to use the time tag when the first byte is
613 ** received to reduce the jitter.
616 if (datum_pts->nbytes == 0) {
617 datum_pts->lastrec = rbufp->recv_time;
621 ** Increment our count to the number of bytes received so far. Return if we
622 ** haven't gotten all seven bytes yet.
625 for (i=0; i<dpend; i++) {
626 datum_pts->retbuf[datum_pts->nbytes+i] = dpt[i];
629 datum_pts->nbytes += dpend;
631 if (datum_pts->nbytes != 7) {
636 ** Convert the seven bytes received in our time buffer to day, hour, minute,
637 ** second, and msecond values. The usec value is not used for anything
638 ** currently. It is just the fractional part of the time stored in units
642 datum_pts->day = 100*(datum_pts->retbuf[0] & 0x0f) +
643 10*((datum_pts->retbuf[1] & 0xf0)>>4) +
644 (datum_pts->retbuf[1] & 0x0f);
646 datum_pts->hour = 10*((datum_pts->retbuf[2] & 0x30)>>4) +
647 (datum_pts->retbuf[2] & 0x0f);
649 datum_pts->minute = 10*((datum_pts->retbuf[3] & 0x70)>>4) +
650 (datum_pts->retbuf[3] & 0x0f);
652 datum_pts->second = 10*((datum_pts->retbuf[4] & 0x70)>>4) +
653 (datum_pts->retbuf[4] & 0x0f);
655 datum_pts->msec = 100*((datum_pts->retbuf[5] & 0xf0) >> 4) +
656 10*(datum_pts->retbuf[5] & 0x0f) +
657 ((datum_pts->retbuf[6] & 0xf0)>>4);
659 datum_pts->usec = 1000*datum_pts->msec;
661 #ifdef DEBUG_DATUM_PTC
663 printf("day %d, hour %d, minute %d, second %d, msec %d\n",
672 ** Get the GMT time zone offset. Note that GMT should be zero if the Datum
673 ** reference time is using GMT as its time base. Otherwise we have to
674 ** determine the offset if the Datum PTS is using time of day as its time
678 goodtime = 0; /* We are not sure about the time and offset yet */
683 ** This is the case where the Datum PTS is using GMT so there is no time
687 tzoff = 0; /* set time zone offset to 0 */
692 ** This is the case where the Datum PTS is using regular time of day for its
693 ** time so we must compute the time zone offset. The way we do it is kind of
694 ** funny but it works. We loop through different time zones (0 to 24) and
695 ** pick the one that gives the smallest error (+- one half hour). The time
696 ** zone offset is stored in the datum_pts structure for future use. Normally,
697 ** the clocktime() routine is only called once (unless the time zone offset
698 ** changes due to daylight savings) since the goodtime flag is set when a
699 ** good time is found (with a good offset). Note that even if the Datum
700 ** PTS is using GMT, this mechanism will still work since it should come up
701 ** with a value for tzoff = 0 (assuming that your system clock is within
702 ** a half hour of the Datum time (even with time zone differences).
705 for (tzoff=0; tzoff<24; tzoff++) {
706 if (clocktime( datum_pts->day,
710 (tzoff + datum_pts->tzoff) % 24,
711 datum_pts->lastrec.l_ui,
712 &datum_pts->yearstart,
713 &datum_pts->lastref.l_ui) ) {
715 error = datum_pts->lastref.l_ui - datum_pts->lastrec.l_ui;
717 #ifdef DEBUG_DATUM_PTC
718 printf("Time Zone (clocktime method) = %d, error = %d\n", tzoff, error);
721 if ((error < 1799) && (error > -1799)) {
722 tzoff = (tzoff + datum_pts->tzoff) % 24;
723 datum_pts->tzoff = tzoff;
726 #ifdef DEBUG_DATUM_PTC
727 printf("Time Zone found (clocktime method) = %d\n",tzoff);
739 ** Make sure that we have a good time from the Datum PTS. Clocktime() also
740 ** sets yearstart and lastref.l_ui. We will have to set astref.l_uf (i.e.,
741 ** the fraction of a second) stuff later.
746 if (!clocktime( datum_pts->day,
751 datum_pts->lastrec.l_ui,
752 &datum_pts->yearstart,
753 &datum_pts->lastref.l_ui) ) {
755 #ifdef DEBUG_DATUM_PTC
758 printf("Error: bad clocktime\n");
759 printf("GMT %d, lastrec %d, yearstart %d, lastref %d\n",
761 datum_pts->lastrec.l_ui,
762 datum_pts->yearstart,
763 datum_pts->lastref.l_ui);
767 msyslog(LOG_ERR, "Datum_PTS: Bad clocktime");
773 #ifdef DEBUG_DATUM_PTC
775 printf("Good clocktime\n");
783 ** We have datum_pts->lastref.l_ui set (which is the integer part of the
784 ** time. Now set the microseconds field.
787 TVUTOTSF(datum_pts->usec, datum_pts->lastref.l_uf);
790 ** Compute the time correction as the difference between the reference
791 ** time (i.e., the Datum time) minus the receive time (system time).
794 tstmp = datum_pts->lastref; /* tstmp is the datum ntp time */
795 L_SUB(&tstmp, &datum_pts->lastrec); /* tstmp is now the correction */
796 datum_pts->coderecv++; /* increment a counter */
798 #ifdef DEBUG_DATUM_PTC
799 dispersion = DATUM_DISPERSION; /* set the dispersion to 0 */
800 ftimerr = dispersion;
801 ftimerr /= (1024.0 * 64.0);
803 printf("dispersion = %d, %f\n", dispersion, ftimerr);
807 ** Pass the new time to ntpd through the refclock_receive function. Note
808 ** that we are not trying to make any corrections due to the time it takes
809 ** for the Datum PTS to send the message back. I am (erroneously) assuming
810 ** that the time for the Datum PTS to send the time back to us is negligable.
811 ** I suspect that this time delay may be as much as 15 ms or so (but probably
812 ** less). For our needs at JPL, this kind of error is ok so it is not
813 ** necessary to use fudge factors in the ntp.conf file. Maybe later we will.
815 /*LFPTOD(&tstmp, doffset);*/
816 refclock_receive(datum_pts->peer);
819 ** Compute sigma squared (not used currently). Maybe later, this could be
820 ** used for the dispersion estimate. The problem is that ntpd does not link
821 ** in the math library so sqrt() is not available. Anyway, this is useful
822 ** for debugging. Maybe later I will just use absolute values for the time
823 ** error to come up with my dispersion estimate. Anyway, for now my dispersion
827 timerr = tstmp.l_ui<<20;
828 timerr |= (tstmp.l_uf>>12) & 0x000fffff;
830 ftimerr /= 1024*1024;
832 if (ftimerr < 0.0) abserr = -ftimerr;
834 if (datum_pts->sigma2 == 0.0) {
835 if (abserr < DATUM_MAX_ERROR) {
836 datum_pts->sigma2 = abserr*abserr;
838 datum_pts->sigma2 = DATUM_MAX_ERROR2;
841 if (abserr < DATUM_MAX_ERROR) {
842 datum_pts->sigma2 = 0.95*datum_pts->sigma2 + 0.05*abserr*abserr;
844 datum_pts->sigma2 = 0.95*datum_pts->sigma2 + 0.05*DATUM_MAX_ERROR2;
848 #ifdef DEBUG_DATUM_PTC
850 printf("Time error = %f seconds\n", ftimerr);
853 #if defined(DEBUG_DATUM_PTC) || defined(LOG_TIME_ERRORS)
855 printf("PTS: day %d, hour %d, minute %d, second %d, msec %d, Time Error %f\n",
866 int refclock_datum_bs;
867 #endif /* REFCLOCK */