refclock_wwvb.c revision 1.8
1 /* $NetBSD: refclock_wwvb.c,v 1.8 2024/08/18 20:47:19 christos Exp $ */ 2 3 /* 4 * refclock_wwvb - clock driver for Spectracom WWVB and GPS receivers 5 */ 6 7 #ifdef HAVE_CONFIG_H 8 #include <config.h> 9 #endif 10 11 #if defined(REFCLOCK) && defined(CLOCK_SPECTRACOM) 12 13 #include "ntpd.h" 14 #include "ntp_io.h" 15 #include "ntp_refclock.h" 16 #include "ntp_calendar.h" 17 #include "ntp_stdlib.h" 18 19 #include <stdio.h> 20 #include <ctype.h> 21 22 #ifdef HAVE_PPSAPI 23 #include "ppsapi_timepps.h" 24 #include "refclock_atom.h" 25 #endif /* HAVE_PPSAPI */ 26 27 /* 28 * This driver supports the Spectracom Model 8170 and Netclock/2 WWVB 29 * Synchronized Clocks and the Netclock/GPS Master Clock. Both the WWVB 30 * and GPS clocks have proven reliable sources of time; however, the 31 * WWVB clocks have proven vulnerable to high ambient conductive RF 32 * interference. The claimed accuracy of the WWVB clocks is 100 us 33 * relative to the broadcast signal, while the claimed accuracy of the 34 * GPS clock is 50 ns; however, in most cases the actual accuracy is 35 * limited by the resolution of the timecode and the latencies of the 36 * serial interface and operating system. 37 * 38 * The WWVB and GPS clocks should be configured for 24-hour display, 39 * AUTO DST off, time zone 0 (UTC), data format 0 or 2 (see below) and 40 * baud rate 9600. If the clock is to used as the source for the IRIG 41 * Audio Decoder (refclock_irig.c in this distribution), it should be 42 * configured for AM IRIG output and IRIG format 1 (IRIG B with 43 * signature control). The GPS clock can be configured either to respond 44 * to a 'T' poll character or left running continuously. 45 * 46 * There are two timecode formats used by these clocks. Format 0, which 47 * is available with both the Netclock/2 and 8170, and format 2, which 48 * is available only with the Netclock/2, specially modified 8170 and 49 * GPS. 50 * 51 * Format 0 (22 ASCII printing characters): 52 * 53 * <cr><lf>i ddd hh:mm:ss TZ=zz<cr><lf> 54 * 55 * on-time = first <cr> 56 * hh:mm:ss = hours, minutes, seconds 57 * i = synchronization flag (' ' = in synch, '?' = out of synch) 58 * 59 * The alarm condition is indicated by other than ' ' at i, which occurs 60 * during initial synchronization and when received signal is lost for 61 * about ten hours. 62 * 63 * Format 2 (24 ASCII printing characters): 64 * 65 * <cr><lf>iqyy ddd hh:mm:ss.fff ld 66 * 67 * on-time = <cr> 68 * i = synchronization flag (' ' = in synch, '?' = out of synch) 69 * q = quality indicator (' ' = locked, 'A'...'D' = unlocked) 70 * yy = year (as broadcast) 71 * ddd = day of year 72 * hh:mm:ss.fff = hours, minutes, seconds, milliseconds 73 * 74 * The alarm condition is indicated by other than ' ' at i, which occurs 75 * during initial synchronization and when received signal is lost for 76 * about ten hours. The unlock condition is indicated by other than ' ' 77 * at q. 78 * 79 * The q is normally ' ' when the time error is less than 1 ms and a 80 * character in the set 'A'...'D' when the time error is less than 10, 81 * 100, 500 and greater than 500 ms respectively. The l is normally ' ', 82 * but is set to 'L' early in the month of an upcoming UTC leap second 83 * and reset to ' ' on the first day of the following month. The d is 84 * set to 'S' for standard time 'I' on the day preceding a switch to 85 * daylight time, 'D' for daylight time and 'O' on the day preceding a 86 * switch to standard time. The start bit of the first <cr> is 87 * synchronized to the indicated time as returned. 88 * 89 * This driver does not need to be told which format is in use - it 90 * figures out which one from the length of the message. The driver 91 * makes no attempt to correct for the intrinsic jitter of the radio 92 * itself, which is a known problem with the older radios. 93 * 94 * PPS Signal Processing 95 * 96 * When PPS signal processing is enabled, and when the system clock has 97 * been set by this or another driver and the PPS signal offset is 98 * within 0.4 s of the system clock offset, the PPS signal replaces the 99 * timecode for as long as the PPS signal is active. If for some reason 100 * the PPS signal fails for one or more poll intervals, the driver 101 * reverts to the timecode. If the timecode fails for one or more poll 102 * intervals, the PPS signal is disconnected. 103 * 104 * Fudge Factors 105 * 106 * This driver can retrieve a table of quality data maintained 107 * internally by the Netclock/2 clock. If flag4 of the fudge 108 * configuration command is set to 1, the driver will retrieve this 109 * table and write it to the clockstats file when the first timecode 110 * message of a new day is received. 111 * 112 * PPS calibration fudge time 1: format 0 .003134, format 2 .004034 113 */ 114 /* 115 * Interface definitions 116 */ 117 #define DEVICE "/dev/wwvb%d" /* device name and unit */ 118 #define SPEED232 B9600 /* uart speed (9600 baud) */ 119 #define PRECISION (-13) /* precision assumed (about 100 us) */ 120 #define PPS_PRECISION (-13) /* precision assumed (about 100 us) */ 121 #define REFID "WWVB" /* reference ID */ 122 #define DESCRIPTION "Spectracom WWVB/GPS Receiver" /* WRU */ 123 124 #define LENWWVB0 22 /* format 0 timecode length */ 125 #define LENWWVB2 24 /* format 2 timecode length */ 126 #define LENWWVB3 29 /* format 3 timecode length */ 127 #define MONLIN 15 /* number of monitoring lines */ 128 129 /* 130 * WWVB unit control structure 131 */ 132 struct wwvbunit { 133 #ifdef HAVE_PPSAPI 134 struct refclock_atom atom; /* PPSAPI structure */ 135 int ppsapi_tried; /* attempt PPSAPI once */ 136 int ppsapi_lit; /* time_pps_create() worked */ 137 int tcount; /* timecode sample counter */ 138 int pcount; /* PPS sample counter */ 139 #endif /* HAVE_PPSAPI */ 140 l_fp laststamp; /* last <CR> timestamp */ 141 int prev_eol_cr; /* was last EOL <CR> (not <LF>)? */ 142 u_char lasthour; /* last hour (for monitor) */ 143 u_char linect; /* count ignored lines (for monitor */ 144 }; 145 146 /* 147 * Function prototypes 148 */ 149 static int wwvb_start (int, struct peer *); 150 static void wwvb_shutdown (int, struct peer *); 151 static void wwvb_receive (struct recvbuf *); 152 static void wwvb_poll (int, struct peer *); 153 static void wwvb_timer (int, struct peer *); 154 #ifdef HAVE_PPSAPI 155 static void wwvb_control (int, const struct refclockstat *, 156 struct refclockstat *, struct peer *); 157 #define WWVB_CONTROL wwvb_control 158 #else 159 #define WWVB_CONTROL (void)(*) 160 noentry 161 #endif /* HAVE_PPSAPI */ 162 163 /* 164 * Transfer vector 165 */ 166 struct refclock refclock_wwvb = { 167 wwvb_start, /* start up driver */ 168 wwvb_shutdown, /* shut down driver */ 169 wwvb_poll, /* transmit poll message */ 170 WWVB_CONTROL, /* fudge set/change notification */ 171 noentry, /* initialize driver (not used) */ 172 noentry, /* not used (old wwvb_buginfo) */ 173 wwvb_timer /* called once per second */ 174 }; 175 176 177 /* 178 * wwvb_start - open the devices and initialize data for processing 179 */ 180 static int 181 wwvb_start( 182 int unit, 183 struct peer *peer 184 ) 185 { 186 register struct wwvbunit *up; 187 struct refclockproc *pp; 188 int fd; 189 char device[20]; 190 191 /* 192 * Open serial port. Use CLK line discipline, if available. 193 */ 194 snprintf(device, sizeof(device), DEVICE, unit); 195 fd = refclock_open(&peer->srcadr, device, SPEED232, LDISC_CLK); 196 if (fd <= 0) 197 return (0); 198 199 /* 200 * Allocate and initialize unit structure 201 */ 202 up = emalloc_zero(sizeof(*up)); 203 pp = peer->procptr; 204 pp->io.clock_recv = wwvb_receive; 205 pp->io.srcclock = peer; 206 pp->io.datalen = 0; 207 pp->io.fd = fd; 208 if (!io_addclock(&pp->io)) { 209 close(fd); 210 pp->io.fd = -1; 211 free(up); 212 return (0); 213 } 214 pp->unitptr = up; 215 216 /* 217 * Initialize miscellaneous variables 218 */ 219 peer->precision = PRECISION; 220 pp->clockdesc = DESCRIPTION; 221 memcpy(&pp->refid, REFID, 4); 222 return (1); 223 } 224 225 226 /* 227 * wwvb_shutdown - shut down the clock 228 */ 229 static void 230 wwvb_shutdown( 231 int unit, 232 struct peer *peer 233 ) 234 { 235 struct refclockproc * pp; 236 struct wwvbunit * up; 237 238 pp = peer->procptr; 239 up = pp->unitptr; 240 if (-1 != pp->io.fd) 241 io_closeclock(&pp->io); 242 if (NULL != up) 243 free(up); 244 } 245 246 247 /* 248 * wwvb_receive - receive data from the serial interface 249 */ 250 static void 251 wwvb_receive( 252 struct recvbuf *rbufp 253 ) 254 { 255 struct wwvbunit *up; 256 struct refclockproc *pp; 257 struct peer *peer; 258 259 l_fp trtmp; /* arrival timestamp */ 260 int tz; /* time zone */ 261 int day, month; /* ddd conversion */ 262 int temp; /* int temp */ 263 char syncchar; /* synchronization indicator */ 264 char qualchar; /* quality indicator */ 265 char leapchar; /* leap indicator */ 266 char dstchar; /* daylight/standard indicator */ 267 char tmpchar; /* trashbin */ 268 269 /* 270 * Initialize pointers and read the timecode and timestamp 271 */ 272 peer = rbufp->recv_peer; 273 pp = peer->procptr; 274 up = pp->unitptr; 275 temp = refclock_gtlin(rbufp, pp->a_lastcode, BMAX, &trtmp); 276 277 /* 278 * Note we get a buffer and timestamp for both a <cr> and <lf>, 279 * but only the <cr> timestamp is retained. Note: in format 0 on 280 * a Netclock/2 or upgraded 8170 the start bit is delayed 100 281 * +-50 us relative to the pps; however, on an unmodified 8170 282 * the start bit can be delayed up to 10 ms. In format 2 the 283 * reading precision is only to the millisecond. Thus, unless 284 * you have a PPS gadget and don't have to have the year, format 285 * 0 provides the lowest jitter. 286 * Save the timestamp of each <CR> in up->laststamp. Lines with 287 * no characters occur for every <LF>, and for some <CR>s when 288 * format 0 is used. Format 0 starts and ends each cycle with a 289 * <CR><LF> pair, format 2 starts each cycle with its only pair. 290 * The preceding <CR> is the on-time character for both formats. 291 * The timestamp provided with non-empty lines corresponds to 292 * the <CR> following the timecode, which is ultimately not used 293 * with format 0 and is used for the following timecode for 294 * format 2. 295 */ 296 if (temp == 0) { 297 if (up->prev_eol_cr) { 298 DPRINTF(2, ("wwvb: <LF> @ %s\n", 299 prettydate(&trtmp))); 300 } else { 301 up->laststamp = trtmp; 302 DPRINTF(2, ("wwvb: <CR> @ %s\n", 303 prettydate(&trtmp))); 304 } 305 up->prev_eol_cr = !up->prev_eol_cr; 306 return; 307 } 308 pp->lencode = temp; 309 pp->lastrec = up->laststamp; 310 up->laststamp = trtmp; 311 up->prev_eol_cr = TRUE; 312 DPRINTF(2, ("wwvb: code @ %s\n" 313 " using %s minus one char\n", 314 prettydate(&trtmp), prettydate(&pp->lastrec))); 315 if (L_ISZERO(&pp->lastrec)) 316 return; 317 318 /* 319 * We get down to business, check the timecode format and decode 320 * its contents. This code uses the timecode length to determine 321 * format 0, 2 or 3. If the timecode has invalid length or is 322 * not in proper format, we declare bad format and exit. 323 */ 324 syncchar = qualchar = leapchar = dstchar = ' '; 325 tz = 0; 326 switch (pp->lencode) { 327 328 case LENWWVB0: 329 330 /* 331 * Timecode format 0: "I ddd hh:mm:ss DTZ=nn" 332 */ 333 if (sscanf(pp->a_lastcode, 334 "%c %3d %2d:%2d:%2d%c%cTZ=%2d", 335 &syncchar, &pp->day, &pp->hour, &pp->minute, 336 &pp->second, &tmpchar, &dstchar, &tz) == 8) { 337 pp->nsec = 0; 338 break; 339 } 340 goto bad_format; 341 342 case LENWWVB2: 343 344 /* 345 * Timecode format 2: "IQyy ddd hh:mm:ss.mmm LD" */ 346 if (sscanf(pp->a_lastcode, 347 "%c%c %2d %3d %2d:%2d:%2d.%3ld %c", 348 &syncchar, &qualchar, &pp->year, &pp->day, 349 &pp->hour, &pp->minute, &pp->second, &pp->nsec, 350 &leapchar) == 9) { 351 pp->nsec *= 1000000; 352 break; 353 } 354 goto bad_format; 355 356 case LENWWVB3: 357 358 /* 359 * Timecode format 3: "0003I yyyymmdd hhmmss+0000SL#" 360 * WARNING: Undocumented, and the on-time character # is 361 * not yet handled correctly by this driver. It may be 362 * as simple as compensating for an additional 1/960 s. 363 */ 364 if (sscanf(pp->a_lastcode, 365 "0003%c %4d%2d%2d %2d%2d%2d+0000%c%c", 366 &syncchar, &pp->year, &month, &day, &pp->hour, 367 &pp->minute, &pp->second, &dstchar, &leapchar) == 8) 368 { 369 pp->day = ymd2yd(pp->year, month, day); 370 pp->nsec = 0; 371 break; 372 } 373 goto bad_format; 374 375 default: 376 bad_format: 377 378 /* 379 * Unknown format: If dumping internal table, record 380 * stats; otherwise, declare bad format. 381 */ 382 if (up->linect > 0) { 383 up->linect--; 384 record_clock_stats(&peer->srcadr, 385 pp->a_lastcode); 386 } else { 387 refclock_report(peer, CEVNT_BADREPLY); 388 } 389 return; 390 } 391 392 /* 393 * Decode synchronization, quality and leap characters. If 394 * unsynchronized, set the leap bits accordingly and exit. 395 * Otherwise, set the leap bits according to the leap character. 396 * Once synchronized, the dispersion depends only on the 397 * quality character. 398 */ 399 switch (qualchar) { 400 401 case ' ': 402 pp->disp = .001; 403 pp->lastref = pp->lastrec; 404 break; 405 406 case 'A': 407 pp->disp = .01; 408 break; 409 410 case 'B': 411 pp->disp = .1; 412 break; 413 414 case 'C': 415 pp->disp = .5; 416 break; 417 418 case 'D': 419 pp->disp = MAXDISPERSE; 420 break; 421 422 default: 423 pp->disp = MAXDISPERSE; 424 refclock_report(peer, CEVNT_BADREPLY); 425 break; 426 } 427 if (syncchar != ' ') 428 pp->leap = LEAP_NOTINSYNC; 429 else if (leapchar == 'L') 430 pp->leap = LEAP_ADDSECOND; 431 else 432 pp->leap = LEAP_NOWARNING; 433 434 /* 435 * Process the new sample in the median filter and determine the 436 * timecode timestamp, but only if the PPS is not in control. 437 */ 438 #ifdef HAVE_PPSAPI 439 up->tcount++; 440 if (peer->flags & FLAG_PPS) 441 return; 442 443 #endif /* HAVE_PPSAPI */ 444 if (!refclock_process_f(pp, pp->fudgetime2)) 445 refclock_report(peer, CEVNT_BADTIME); 446 } 447 448 449 /* 450 * wwvb_timer - called once per second by the transmit procedure 451 */ 452 static void 453 wwvb_timer( 454 int unit, 455 struct peer *peer 456 ) 457 { 458 register struct wwvbunit *up; 459 struct refclockproc *pp; 460 char pollchar; /* character sent to clock */ 461 #ifdef DEBUG 462 l_fp now; 463 #endif 464 465 /* 466 * Time to poll the clock. The Spectracom clock responds to a 467 * 'T' by returning a timecode in the format(s) specified above. 468 * Note there is no checking on state, since this may not be the 469 * only customer reading the clock. Only one customer need poll 470 * the clock; all others just listen in. 471 */ 472 pp = peer->procptr; 473 up = pp->unitptr; 474 if (up->linect > 0) 475 pollchar = 'R'; 476 else 477 pollchar = 'T'; 478 if (write(pp->io.fd, &pollchar, 1) != 1) 479 refclock_report(peer, CEVNT_FAULT); 480 #ifdef DEBUG 481 get_systime(&now); 482 if (debug) 483 printf("%c poll at %s\n", pollchar, prettydate(&now)); 484 #endif 485 #ifdef HAVE_PPSAPI 486 if (up->ppsapi_lit && 487 refclock_pps(peer, &up->atom, pp->sloppyclockflag) > 0) { 488 up->pcount++, 489 peer->flags |= FLAG_PPS; 490 peer->precision = PPS_PRECISION; 491 } 492 #endif /* HAVE_PPSAPI */ 493 } 494 495 496 /* 497 * wwvb_poll - called by the transmit procedure 498 */ 499 static void 500 wwvb_poll( 501 int unit, 502 struct peer *peer 503 ) 504 { 505 register struct wwvbunit *up; 506 struct refclockproc *pp; 507 508 /* 509 * Sweep up the samples received since the last poll. If none 510 * are received, declare a timeout and keep going. 511 */ 512 pp = peer->procptr; 513 up = pp->unitptr; 514 pp->polls++; 515 516 /* 517 * If the monitor flag is set (flag4), we dump the internal 518 * quality table at the first timecode beginning the day. 519 */ 520 if (pp->sloppyclockflag & CLK_FLAG4 && pp->hour < 521 (int)up->lasthour) 522 up->linect = MONLIN; 523 up->lasthour = (u_char)pp->hour; 524 525 /* 526 * Process median filter samples. If none received, declare a 527 * timeout and keep going. 528 */ 529 #ifdef HAVE_PPSAPI 530 if (up->pcount == 0) { 531 peer->flags &= ~FLAG_PPS; 532 peer->precision = PRECISION; 533 } 534 if (up->tcount == 0) { 535 pp->coderecv = pp->codeproc; 536 refclock_report(peer, CEVNT_TIMEOUT); 537 return; 538 } 539 up->pcount = up->tcount = 0; 540 #else /* HAVE_PPSAPI */ 541 if (pp->coderecv == pp->codeproc) { 542 refclock_report(peer, CEVNT_TIMEOUT); 543 return; 544 } 545 #endif /* HAVE_PPSAPI */ 546 refclock_receive(peer); 547 record_clock_stats(&peer->srcadr, pp->a_lastcode); 548 #ifdef DEBUG 549 if (debug) 550 printf("wwvb: timecode %d %s\n", pp->lencode, 551 pp->a_lastcode); 552 #endif 553 } 554 555 556 /* 557 * wwvb_control - fudge parameters have been set or changed 558 */ 559 #ifdef HAVE_PPSAPI 560 static void 561 wwvb_control( 562 int unit, 563 const struct refclockstat *in_st, 564 struct refclockstat *out_st, 565 struct peer *peer 566 ) 567 { 568 register struct wwvbunit *up; 569 struct refclockproc *pp; 570 571 pp = peer->procptr; 572 up = pp->unitptr; 573 574 if (!(pp->sloppyclockflag & CLK_FLAG1)) { 575 if (!up->ppsapi_tried) 576 return; 577 up->ppsapi_tried = 0; 578 if (!up->ppsapi_lit) 579 return; 580 peer->flags &= ~FLAG_PPS; 581 peer->precision = PRECISION; 582 time_pps_destroy(up->atom.handle); 583 up->atom.handle = 0; 584 up->ppsapi_lit = 0; 585 return; 586 } 587 588 if (up->ppsapi_tried) 589 return; 590 /* 591 * Light up the PPSAPI interface. 592 */ 593 up->ppsapi_tried = 1; 594 if (refclock_ppsapi(pp->io.fd, &up->atom)) { 595 up->ppsapi_lit = 1; 596 return; 597 } 598 599 msyslog(LOG_WARNING, "%s flag1 1 but PPSAPI fails", 600 refnumtoa(&peer->srcadr)); 601 } 602 #endif /* HAVE_PPSAPI */ 603 604 #else 605 NONEMPTY_TRANSLATION_UNIT 606 #endif /* REFCLOCK */ 607
Indexes created Wed May 06 00:24:28 UTC 2026