1 /* $NetBSD: refclock_wwvb.c,v 1.2 2012/02/01 07:46:22 kardel 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, struct refclockstat *, 156 struct refclockstat *, struct peer *); 157 #define WWVB_CONTROL wwvb_control 158 #else 159 #define WWVB_CONTROL noentry 160 #endif /* HAVE_PPSAPI */ 161 162 /* 163 * Transfer vector 164 */ 165 struct refclock refclock_wwvb = { 166 wwvb_start, /* start up driver */ 167 wwvb_shutdown, /* shut down driver */ 168 wwvb_poll, /* transmit poll message */ 169 WWVB_CONTROL, /* fudge set/change notification */ 170 noentry, /* initialize driver (not used) */ 171 noentry, /* not used (old wwvb_buginfo) */ 172 wwvb_timer /* called once per second */ 173 }; 174 175 176 /* 177 * wwvb_start - open the devices and initialize data for processing 178 */ 179 static int 180 wwvb_start( 181 int unit, 182 struct peer *peer 183 ) 184 { 185 register struct wwvbunit *up; 186 struct refclockproc *pp; 187 int fd; 188 char device[20]; 189 190 /* 191 * Open serial port. Use CLK line discipline, if available. 192 */ 193 snprintf(device, sizeof(device), DEVICE, unit); 194 fd = refclock_open(device, SPEED232, LDISC_CLK); 195 if (fd <= 0) 196 return (0); 197 198 /* 199 * Allocate and initialize unit structure 200 */ 201 up = emalloc_zero(sizeof(*up)); 202 pp = peer->procptr; 203 pp->io.clock_recv = wwvb_receive; 204 pp->io.srcclock = (void *)peer; 205 pp->io.datalen = 0; 206 pp->io.fd = fd; 207 if (!io_addclock(&pp->io)) { 208 close(fd); 209 pp->io.fd = -1; 210 free(up); 211 return (0); 212 } 213 pp->unitptr = up; 214 215 /* 216 * Initialize miscellaneous variables 217 */ 218 peer->precision = PRECISION; 219 pp->clockdesc = DESCRIPTION; 220 memcpy(&pp->refid, REFID, 4); 221 return (1); 222 } 223 224 225 /* 226 * wwvb_shutdown - shut down the clock 227 */ 228 static void 229 wwvb_shutdown( 230 int unit, 231 struct peer *peer 232 ) 233 { 234 register struct wwvbunit *up; 235 struct refclockproc *pp; 236 237 pp = peer->procptr; 238 up = pp->unitptr; 239 if (-1 != pp->io.fd) 240 io_closeclock(&pp->io); 241 if (NULL != up) 242 free(up); 243 } 244 245 246 /* 247 * wwvb_receive - receive data from the serial interface 248 */ 249 static void 250 wwvb_receive( 251 struct recvbuf *rbufp 252 ) 253 { 254 struct wwvbunit *up; 255 struct refclockproc *pp; 256 struct peer *peer; 257 258 l_fp trtmp; /* arrival timestamp */ 259 int tz; /* time zone */ 260 int day, month; /* ddd conversion */ 261 int temp; /* int temp */ 262 char syncchar; /* synchronization indicator */ 263 char qualchar; /* quality indicator */ 264 char leapchar; /* leap indicator */ 265 char dstchar; /* daylight/standard indicator */ 266 char tmpchar; /* trashbin */ 267 268 /* 269 * Initialize pointers and read the timecode and timestamp 270 */ 271 peer = rbufp->recv_peer; 272 pp = peer->procptr; 273 up = pp->unitptr; 274 temp = refclock_gtlin(rbufp, pp->a_lastcode, BMAX, &trtmp); 275 276 /* 277 * Note we get a buffer and timestamp for both a <cr> and <lf>, 278 * but only the <cr> timestamp is retained. Note: in format 0 on 279 * a Netclock/2 or upgraded 8170 the start bit is delayed 100 280 * +-50 us relative to the pps; however, on an unmodified 8170 281 * the start bit can be delayed up to 10 ms. In format 2 the 282 * reading precision is only to the millisecond. Thus, unless 283 * you have a PPS gadget and don't have to have the year, format 284 * 0 provides the lowest jitter. 285 * Save the timestamp of each <CR> in up->laststamp. Lines with 286 * no characters occur for every <LF>, and for some <CR>s when 287 * format 0 is used. Format 0 starts and ends each cycle with a 288 * <CR><LF> pair, format 2 starts each cycle with its only pair. 289 * The preceding <CR> is the on-time character for both formats. 290 * The timestamp provided with non-empty lines corresponds to 291 * the <CR> following the timecode, which is ultimately not used 292 * with format 0 and is used for the following timecode for 293 * format 2. 294 */ 295 if (temp == 0) { 296 if (up->prev_eol_cr) { 297 DPRINTF(2, ("wwvb: <LF> @ %s\n", 298 prettydate(&trtmp))); 299 } else { 300 up->laststamp = trtmp; 301 DPRINTF(2, ("wwvb: <CR> @ %s\n", 302 prettydate(&trtmp))); 303 } 304 up->prev_eol_cr = !up->prev_eol_cr; 305 return; 306 } 307 pp->lencode = temp; 308 pp->lastrec = up->laststamp; 309 up->laststamp = trtmp; 310 up->prev_eol_cr = TRUE; 311 DPRINTF(2, ("wwvb: code @ %s\n" 312 " using %s minus one char\n", 313 prettydate(&trtmp), prettydate(&pp->lastrec))); 314 if (L_ISZERO(&pp->lastrec)) 315 return; 316 317 /* 318 * We get down to business, check the timecode format and decode 319 * its contents. This code uses the timecode length to determine 320 * format 0, 2 or 3. If the timecode has invalid length or is 321 * not in proper format, we declare bad format and exit. 322 */ 323 syncchar = qualchar = leapchar = dstchar = ' '; 324 tz = 0; 325 switch (pp->lencode) { 326 327 case LENWWVB0: 328 329 /* 330 * Timecode format 0: "I ddd hh:mm:ss DTZ=nn" 331 */ 332 if (sscanf(pp->a_lastcode, 333 "%c %3d %2d:%2d:%2d%c%cTZ=%2d", 334 &syncchar, &pp->day, &pp->hour, &pp->minute, 335 &pp->second, &tmpchar, &dstchar, &tz) == 8) { 336 pp->nsec = 0; 337 break; 338 } 339 goto bad_format; 340 341 case LENWWVB2: 342 343 /* 344 * Timecode format 2: "IQyy ddd hh:mm:ss.mmm LD" */ 345 if (sscanf(pp->a_lastcode, 346 "%c%c %2d %3d %2d:%2d:%2d.%3ld %c", 347 &syncchar, &qualchar, &pp->year, &pp->day, 348 &pp->hour, &pp->minute, &pp->second, &pp->nsec, 349 &leapchar) == 9) { 350 pp->nsec *= 1000000; 351 break; 352 } 353 goto bad_format; 354 355 case LENWWVB3: 356 357 /* 358 * Timecode format 3: "0003I yyyymmdd hhmmss+0000SL#" 359 * WARNING: Undocumented, and the on-time character # is 360 * not yet handled correctly by this driver. It may be 361 * as simple as compensating for an additional 1/960 s. 362 */ 363 if (sscanf(pp->a_lastcode, 364 "0003%c %4d%2d%2d %2d%2d%2d+0000%c%c", 365 &syncchar, &pp->year, &month, &day, &pp->hour, 366 &pp->minute, &pp->second, &dstchar, &leapchar) == 8) 367 { 368 pp->day = ymd2yd(pp->year, month, day); 369 pp->nsec = 0; 370 break; 371 } 372 goto bad_format; 373 374 default: 375 bad_format: 376 377 /* 378 * Unknown format: If dumping internal table, record 379 * stats; otherwise, declare bad format. 380 */ 381 if (up->linect > 0) { 382 up->linect--; 383 record_clock_stats(&peer->srcadr, 384 pp->a_lastcode); 385 } else { 386 refclock_report(peer, CEVNT_BADREPLY); 387 } 388 return; 389 } 390 391 /* 392 * Decode synchronization, quality and leap characters. If 393 * unsynchronized, set the leap bits accordingly and exit. 394 * Otherwise, set the leap bits according to the leap character. 395 * Once synchronized, the dispersion depends only on the 396 * quality character. 397 */ 398 switch (qualchar) { 399 400 case ' ': 401 pp->disp = .001; 402 pp->lastref = pp->lastrec; 403 break; 404 405 case 'A': 406 pp->disp = .01; 407 break; 408 409 case 'B': 410 pp->disp = .1; 411 break; 412 413 case 'C': 414 pp->disp = .5; 415 break; 416 417 case 'D': 418 pp->disp = MAXDISPERSE; 419 break; 420 421 default: 422 pp->disp = MAXDISPERSE; 423 refclock_report(peer, CEVNT_BADREPLY); 424 break; 425 } 426 if (syncchar != ' ') 427 pp->leap = LEAP_NOTINSYNC; 428 else if (leapchar == 'L') 429 pp->leap = LEAP_ADDSECOND; 430 else 431 pp->leap = LEAP_NOWARNING; 432 433 /* 434 * Process the new sample in the median filter and determine the 435 * timecode timestamp, but only if the PPS is not in control. 436 */ 437 #ifdef HAVE_PPSAPI 438 up->tcount++; 439 if (peer->flags & FLAG_PPS) 440 return; 441 442 #endif /* HAVE_PPSAPI */ 443 if (!refclock_process_f(pp, pp->fudgetime2)) 444 refclock_report(peer, CEVNT_BADTIME); 445 } 446 447 448 /* 449 * wwvb_timer - called once per second by the transmit procedure 450 */ 451 static void 452 wwvb_timer( 453 int unit, 454 struct peer *peer 455 ) 456 { 457 register struct wwvbunit *up; 458 struct refclockproc *pp; 459 char pollchar; /* character sent to clock */ 460 l_fp now; 461 462 /* 463 * Time to poll the clock. The Spectracom clock responds to a 464 * 'T' by returning a timecode in the format(s) specified above. 465 * Note there is no checking on state, since this may not be the 466 * only customer reading the clock. Only one customer need poll 467 * the clock; all others just listen in. 468 */ 469 pp = peer->procptr; 470 up = pp->unitptr; 471 if (up->linect > 0) 472 pollchar = 'R'; 473 else 474 pollchar = 'T'; 475 if (write(pp->io.fd, &pollchar, 1) != 1) 476 refclock_report(peer, CEVNT_FAULT); 477 #ifdef DEBUG 478 get_systime(&now); 479 if (debug) 480 printf("%c poll at %s\n", pollchar, prettydate(&now)); 481 #endif 482 #ifdef HAVE_PPSAPI 483 if (up->ppsapi_lit && 484 refclock_pps(peer, &up->atom, pp->sloppyclockflag) > 0) { 485 up->pcount++, 486 peer->flags |= FLAG_PPS; 487 peer->precision = PPS_PRECISION; 488 } 489 #endif /* HAVE_PPSAPI */ 490 } 491 492 493 /* 494 * wwvb_poll - called by the transmit procedure 495 */ 496 static void 497 wwvb_poll( 498 int unit, 499 struct peer *peer 500 ) 501 { 502 register struct wwvbunit *up; 503 struct refclockproc *pp; 504 505 /* 506 * Sweep up the samples received since the last poll. If none 507 * are received, declare a timeout and keep going. 508 */ 509 pp = peer->procptr; 510 up = pp->unitptr; 511 pp->polls++; 512 513 /* 514 * If the monitor flag is set (flag4), we dump the internal 515 * quality table at the first timecode beginning the day. 516 */ 517 if (pp->sloppyclockflag & CLK_FLAG4 && pp->hour < 518 (int)up->lasthour) 519 up->linect = MONLIN; 520 up->lasthour = (u_char)pp->hour; 521 522 /* 523 * Process median filter samples. If none received, declare a 524 * timeout and keep going. 525 */ 526 #ifdef HAVE_PPSAPI 527 if (up->pcount == 0) { 528 peer->flags &= ~FLAG_PPS; 529 peer->precision = PRECISION; 530 } 531 if (up->tcount == 0) { 532 pp->coderecv = pp->codeproc; 533 refclock_report(peer, CEVNT_TIMEOUT); 534 return; 535 } 536 up->pcount = up->tcount = 0; 537 #else /* HAVE_PPSAPI */ 538 if (pp->coderecv == pp->codeproc) { 539 refclock_report(peer, CEVNT_TIMEOUT); 540 return; 541 } 542 #endif /* HAVE_PPSAPI */ 543 refclock_receive(peer); 544 record_clock_stats(&peer->srcadr, pp->a_lastcode); 545 #ifdef DEBUG 546 if (debug) 547 printf("wwvb: timecode %d %s\n", pp->lencode, 548 pp->a_lastcode); 549 #endif 550 } 551 552 553 /* 554 * wwvb_control - fudge parameters have been set or changed 555 */ 556 #ifdef HAVE_PPSAPI 557 static void 558 wwvb_control( 559 int unit, 560 struct refclockstat *in_st, 561 struct refclockstat *out_st, 562 struct peer *peer 563 ) 564 { 565 register struct wwvbunit *up; 566 struct refclockproc *pp; 567 568 pp = peer->procptr; 569 up = pp->unitptr; 570 571 if (!(pp->sloppyclockflag & CLK_FLAG1)) { 572 if (!up->ppsapi_tried) 573 return; 574 up->ppsapi_tried = 0; 575 if (!up->ppsapi_lit) 576 return; 577 peer->flags &= ~FLAG_PPS; 578 peer->precision = PRECISION; 579 time_pps_destroy(up->atom.handle); 580 up->atom.handle = 0; 581 up->ppsapi_lit = 0; 582 return; 583 } 584 585 if (up->ppsapi_tried) 586 return; 587 /* 588 * Light up the PPSAPI interface. 589 */ 590 up->ppsapi_tried = 1; 591 if (refclock_ppsapi(pp->io.fd, &up->atom)) { 592 up->ppsapi_lit = 1; 593 return; 594 } 595 596 NLOG(NLOG_CLOCKINFO) 597 msyslog(LOG_WARNING, "%s flag1 1 but PPSAPI fails", 598 refnumtoa(&peer->srcadr)); 599 } 600 #endif /* HAVE_PPSAPI */ 601 602 #else 603 int refclock_wwvb_bs; 604 #endif /* REFCLOCK */ 605