1 /* 2 * refclock_as2201 - clock driver for the Austron 2201A GPS 3 * Timing Receiver 4 */ 5 #ifdef HAVE_CONFIG_H 6 #include <config.h> 7 #endif 8 9 #if defined(REFCLOCK) && defined(CLOCK_AS2201) 10 11 #include "ntpd.h" 12 #include "ntp_io.h" 13 #include "ntp_refclock.h" 14 #include "ntp_unixtime.h" 15 #include "ntp_stdlib.h" 16 17 #include <stdio.h> 18 #include <ctype.h> 19 20 /* 21 * This driver supports the Austron 2200A/2201A GPS Receiver with 22 * Buffered RS-232-C Interface Module. Note that the original 2200/2201 23 * receivers will not work reliably with this driver, since the older 24 * design cannot accept input commands at any reasonable data rate. 25 * 26 * The program sends a "*toc\r" to the radio and expects a response of 27 * the form "yy:ddd:hh:mm:ss.mmm\r" where yy = year of century, ddd = 28 * day of year, hh:mm:ss = second of day and mmm = millisecond of 29 * second. Then, it sends statistics commands to the radio and expects 30 * a multi-line reply showing the corresponding statistics or other 31 * selected data. Statistics commands are sent in order as determined by 32 * a vector of commands; these might have to be changed with different 33 * radio options. If flag4 of the fudge configuration command is set to 34 * 1, the statistics data are written to the clockstats file for later 35 * processing. 36 * 37 * In order for this code to work, the radio must be placed in non- 38 * interactive mode using the "off" command and with a single <cr> 39 * response using the "term cr" command. The setting of the "echo" 40 * and "df" commands does not matter. The radio should select UTC 41 * timescale using the "ts utc" command. 42 * 43 * There are two modes of operation for this driver. The first with 44 * default configuration is used with stock kernels and serial-line 45 * drivers and works with almost any machine. In this mode the driver 46 * assumes the radio captures a timestamp upon receipt of the "*" that 47 * begins the driver query. Accuracies in this mode are in the order of 48 * a millisecond or two and the receiver can be connected to only one 49 * host. 50 * 51 * The second mode of operation can be used for SunOS kernels that have 52 * been modified with the ppsclock streams module included in this 53 * distribution. The mode is enabled if flag3 of the fudge configuration 54 * command has been set to 1. In this mode a precise timestamp is 55 * available using a gadget box and 1-pps signal from the receiver. This 56 * improves the accuracy to the order of a few tens of microseconds. In 57 * addition, the serial output and 1-pps signal can be bussed to more 58 * than one hosts, but only one of them should be connected to the 59 * radio input data line. 60 */ 61 62 /* 63 * GPS Definitions 64 */ 65 #define SMAX 200 /* statistics buffer length */ 66 #define DEVICE "/dev/gps%d" /* device name and unit */ 67 #define SPEED232 B9600 /* uart speed (9600 baud) */ 68 #define PRECISION (-20) /* precision assumed (about 1 us) */ 69 #define REFID "GPS\0" /* reference ID */ 70 #define DESCRIPTION "Austron 2201A GPS Receiver" /* WRU */ 71 72 #define LENTOC 19 /* yy:ddd:hh:mm:ss.mmm timecode lngth */ 73 74 /* 75 * AS2201 unit control structure. 76 */ 77 struct as2201unit { 78 char *lastptr; /* statistics buffer pointer */ 79 char stats[SMAX]; /* statistics buffer */ 80 int linect; /* count of lines remaining */ 81 int index; /* current statistics command */ 82 }; 83 84 /* 85 * Radio commands to extract statitistics 86 * 87 * A command consists of an ASCII string terminated by a <cr> (\r). The 88 * command list consist of a sequence of commands terminated by a null 89 * string ("\0"). One command from the list is sent immediately 90 * following each received timecode (*toc\r command) and the ASCII 91 * strings received from the radio are saved along with the timecode in 92 * the clockstats file. Subsequent commands are sent at each timecode, 93 * with the last one in the list followed by the first one. The data 94 * received from the radio consist of ASCII strings, each terminated by 95 * a <cr> (\r) character. The number of strings for each command is 96 * specified as the first line of output as an ASCII-encode number. Note 97 * that the ETF command requires the Input Buffer Module and the LORAN 98 * commands require the LORAN Assist Module. However, if these modules 99 * are not installed, the radio and this driver will continue to operate 100 * successfuly, but no data will be captured for these commands. 101 */ 102 static char stat_command[][30] = { 103 "ITF\r", /* internal time/frequency */ 104 "ETF\r", /* external time/frequency */ 105 "LORAN ENSEMBLE\r", /* GPS/LORAN ensemble statistics */ 106 "LORAN TDATA\r", /* LORAN signal data */ 107 "ID;OPT;VER\r", /* model; options; software version */ 108 109 "ITF\r", /* internal time/frequency */ 110 "ETF\r", /* external time/frequency */ 111 "LORAN ENSEMBLE\r", /* GPS/LORAN ensemble statistics */ 112 "TRSTAT\r", /* satellite tracking status */ 113 "POS;PPS;PPSOFF\r", /* position, pps source, offsets */ 114 115 "ITF\r", /* internal time/frequency */ 116 "ETF\r", /* external time/frequency */ 117 "LORAN ENSEMBLE\r", /* GPS/LORAN ensemble statistics */ 118 "LORAN TDATA\r", /* LORAN signal data */ 119 "UTC\r", /* UTC leap info */ 120 121 "ITF\r", /* internal time/frequency */ 122 "ETF\r", /* external time/frequency */ 123 "LORAN ENSEMBLE\r", /* GPS/LORAN ensemble statistics */ 124 "TRSTAT\r", /* satellite tracking status */ 125 "OSC;ET;TEMP\r", /* osc type; tune volts; oven temp */ 126 "\0" /* end of table */ 127 }; 128 129 /* 130 * Function prototypes 131 */ 132 static int as2201_start (int, struct peer *); 133 static void as2201_shutdown (int, struct peer *); 134 static void as2201_receive (struct recvbuf *); 135 static void as2201_poll (int, struct peer *); 136 137 /* 138 * Transfer vector 139 */ 140 struct refclock refclock_as2201 = { 141 as2201_start, /* start up driver */ 142 as2201_shutdown, /* shut down driver */ 143 as2201_poll, /* transmit poll message */ 144 noentry, /* not used (old as2201_control) */ 145 noentry, /* initialize driver (not used) */ 146 noentry, /* not used (old as2201_buginfo) */ 147 NOFLAGS /* not used */ 148 }; 149 150 151 /* 152 * as2201_start - open the devices and initialize data for processing 153 */ 154 static int 155 as2201_start( 156 int unit, 157 struct peer *peer 158 ) 159 { 160 register struct as2201unit *up; 161 struct refclockproc *pp; 162 int fd; 163 char gpsdev[20]; 164 165 /* 166 * Open serial port. Use CLK line discipline, if available. 167 */ 168 snprintf(gpsdev, sizeof(gpsdev), DEVICE, unit); 169 fd = refclock_open(gpsdev, SPEED232, LDISC_CLK); 170 if (fd <= 0) 171 return (0); 172 173 /* 174 * Allocate and initialize unit structure 175 */ 176 up = emalloc_zero(sizeof(*up)); 177 pp = peer->procptr; 178 pp->io.clock_recv = as2201_receive; 179 pp->io.srcclock = peer; 180 pp->io.datalen = 0; 181 pp->io.fd = fd; 182 if (!io_addclock(&pp->io)) { 183 close(fd); 184 pp->io.fd = -1; 185 free(up); 186 return (0); 187 } 188 pp->unitptr = up; 189 190 /* 191 * Initialize miscellaneous variables 192 */ 193 peer->precision = PRECISION; 194 pp->clockdesc = DESCRIPTION; 195 memcpy((char *)&pp->refid, REFID, 4); 196 up->lastptr = up->stats; 197 up->index = 0; 198 return (1); 199 } 200 201 202 /* 203 * as2201_shutdown - shut down the clock 204 */ 205 static void 206 as2201_shutdown( 207 int unit, 208 struct peer *peer 209 ) 210 { 211 register struct as2201unit *up; 212 struct refclockproc *pp; 213 214 pp = peer->procptr; 215 up = pp->unitptr; 216 if (-1 != pp->io.fd) 217 io_closeclock(&pp->io); 218 if (NULL != up) 219 free(up); 220 } 221 222 223 /* 224 * as2201__receive - receive data from the serial interface 225 */ 226 static void 227 as2201_receive( 228 struct recvbuf *rbufp 229 ) 230 { 231 register struct as2201unit *up; 232 struct refclockproc *pp; 233 struct peer *peer; 234 l_fp trtmp; 235 size_t octets; 236 237 /* 238 * Initialize pointers and read the timecode and timestamp. 239 */ 240 peer = rbufp->recv_peer; 241 pp = peer->procptr; 242 up = pp->unitptr; 243 pp->lencode = refclock_gtlin(rbufp, pp->a_lastcode, BMAX, &trtmp); 244 #ifdef DEBUG 245 if (debug) 246 printf("gps: timecode %d %d %s\n", 247 up->linect, pp->lencode, pp->a_lastcode); 248 #endif 249 if (pp->lencode == 0) 250 return; 251 252 /* 253 * If linect is greater than zero, we must be in the middle of a 254 * statistics operation, so simply tack the received data at the 255 * end of the statistics string. If not, we could either have 256 * just received the timecode itself or a decimal number 257 * indicating the number of following lines of the statistics 258 * reply. In the former case, write the accumulated statistics 259 * data to the clockstats file and continue onward to process 260 * the timecode; in the later case, save the number of lines and 261 * quietly return. 262 */ 263 if (pp->sloppyclockflag & CLK_FLAG2) 264 pp->lastrec = trtmp; 265 if (up->linect > 0) { 266 up->linect--; 267 if ((int)(up->lastptr - up->stats + pp->lencode) > SMAX - 2) 268 return; 269 *up->lastptr++ = ' '; 270 memcpy(up->lastptr, pp->a_lastcode, 1 + pp->lencode); 271 up->lastptr += pp->lencode; 272 return; 273 } else { 274 if (pp->lencode == 1) { 275 up->linect = atoi(pp->a_lastcode); 276 return; 277 } else { 278 record_clock_stats(&peer->srcadr, up->stats); 279 #ifdef DEBUG 280 if (debug) 281 printf("gps: stat %s\n", up->stats); 282 #endif 283 } 284 } 285 up->lastptr = up->stats; 286 *up->lastptr = '\0'; 287 288 /* 289 * We get down to business, check the timecode format and decode 290 * its contents. If the timecode has invalid length or is not in 291 * proper format, we declare bad format and exit. 292 */ 293 if (pp->lencode < LENTOC) { 294 refclock_report(peer, CEVNT_BADREPLY); 295 return; 296 } 297 298 /* 299 * Timecode format: "yy:ddd:hh:mm:ss.mmm" 300 */ 301 if (sscanf(pp->a_lastcode, "%2d:%3d:%2d:%2d:%2d.%3ld", &pp->year, 302 &pp->day, &pp->hour, &pp->minute, &pp->second, &pp->nsec) 303 != 6) { 304 refclock_report(peer, CEVNT_BADREPLY); 305 return; 306 } 307 pp->nsec *= 1000000; 308 309 /* 310 * Test for synchronization (this is a temporary crock). 311 */ 312 if (pp->a_lastcode[2] != ':') 313 pp->leap = LEAP_NOTINSYNC; 314 else 315 pp->leap = LEAP_NOWARNING; 316 317 /* 318 * Process the new sample in the median filter and determine the 319 * timecode timestamp. 320 */ 321 if (!refclock_process(pp)) { 322 refclock_report(peer, CEVNT_BADTIME); 323 return; 324 } 325 326 /* 327 * If CLK_FLAG4 is set, initialize the statistics buffer and 328 * send the next command. If not, simply write the timecode to 329 * the clockstats file. 330 */ 331 if ((int)(up->lastptr - up->stats + pp->lencode) > SMAX - 2) 332 return; 333 memcpy(up->lastptr, pp->a_lastcode, pp->lencode); 334 up->lastptr += pp->lencode; 335 if (pp->sloppyclockflag & CLK_FLAG4) { 336 octets = strlen(stat_command[up->index]); 337 if ((int)(up->lastptr - up->stats + 1 + octets) > SMAX - 2) 338 return; 339 *up->lastptr++ = ' '; 340 memcpy(up->lastptr, stat_command[up->index], octets); 341 up->lastptr += octets - 1; 342 *up->lastptr = '\0'; 343 (void)write(pp->io.fd, stat_command[up->index], 344 strlen(stat_command[up->index])); 345 up->index++; 346 if (*stat_command[up->index] == '\0') 347 up->index = 0; 348 } 349 } 350 351 352 /* 353 * as2201_poll - called by the transmit procedure 354 * 355 * We go to great pains to avoid changing state here, since there may be 356 * more than one eavesdropper receiving the same timecode. 357 */ 358 static void 359 as2201_poll( 360 int unit, 361 struct peer *peer 362 ) 363 { 364 struct refclockproc *pp; 365 366 /* 367 * Send a "\r*toc\r" to get things going. We go to great pains 368 * to avoid changing state, since there may be more than one 369 * eavesdropper watching the radio. 370 */ 371 pp = peer->procptr; 372 if (write(pp->io.fd, "\r*toc\r", 6) != 6) { 373 refclock_report(peer, CEVNT_FAULT); 374 } else { 375 pp->polls++; 376 if (!(pp->sloppyclockflag & CLK_FLAG2)) 377 get_systime(&pp->lastrec); 378 } 379 if (pp->coderecv == pp->codeproc) { 380 refclock_report(peer, CEVNT_TIMEOUT); 381 return; 382 } 383 refclock_receive(peer); 384 } 385 386 #else 387 int refclock_as2201_bs; 388 #endif /* REFCLOCK */ 389