1 /*- 2 * ---------------------------------------------------------------------------- 3 * "THE BEER-WARE LICENSE" (Revision 42): 4 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you 5 * can do whatever you want with this stuff. If we meet some day, and you think 6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp 7 * ---------------------------------------------------------------------------- 8 */ 9 10 #include <sys/cdefs.h> 11 __FBSDID("$FreeBSD$"); 12 13 #include "opt_ntp.h" 14 15 #include <sys/param.h> 16 #include <sys/kernel.h> 17 #include <sys/sysctl.h> 18 #include <sys/syslog.h> 19 #include <sys/systm.h> 20 #include <sys/timepps.h> 21 #include <sys/timetc.h> 22 #include <sys/timex.h> 23 24 /* 25 * A large step happens on boot. This constant detects such steps. 26 * It is relatively small so that ntp_update_second gets called enough 27 * in the typical 'missed a couple of seconds' case, but doesn't loop 28 * forever when the time step is large. 29 */ 30 #define LARGE_STEP 200 31 32 /* 33 * Implement a dummy timecounter which we can use until we get a real one 34 * in the air. This allows the console and other early stuff to use 35 * time services. 36 */ 37 38 static u_int 39 dummy_get_timecount(struct timecounter *tc) 40 { 41 static u_int now; 42 43 return (++now); 44 } 45 46 static struct timecounter dummy_timecounter = { 47 dummy_get_timecount, 0, ~0u, 1000000, "dummy", -1000000 48 }; 49 50 struct timehands { 51 /* These fields must be initialized by the driver. */ 52 struct timecounter *th_counter; 53 int64_t th_adjustment; 54 u_int64_t th_scale; 55 u_int th_offset_count; 56 struct bintime th_offset; 57 struct timeval th_microtime; 58 struct timespec th_nanotime; 59 /* Fields not to be copied in tc_windup start with th_generation. */ 60 volatile u_int th_generation; 61 struct timehands *th_next; 62 }; 63 64 static struct timehands th0; 65 static struct timehands th9 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th0}; 66 static struct timehands th8 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th9}; 67 static struct timehands th7 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th8}; 68 static struct timehands th6 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th7}; 69 static struct timehands th5 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th6}; 70 static struct timehands th4 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th5}; 71 static struct timehands th3 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th4}; 72 static struct timehands th2 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th3}; 73 static struct timehands th1 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th2}; 74 static struct timehands th0 = { 75 &dummy_timecounter, 76 0, 77 (uint64_t)-1 / 1000000, 78 0, 79 {1, 0}, 80 {0, 0}, 81 {0, 0}, 82 1, 83 &th1 84 }; 85 86 static struct timehands *volatile timehands = &th0; 87 struct timecounter *timecounter = &dummy_timecounter; 88 static struct timecounter *timecounters = &dummy_timecounter; 89 90 time_t time_second = 1; 91 time_t time_uptime = 1; 92 93 static struct bintime boottimebin; 94 struct timeval boottime; 95 static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS); 96 SYSCTL_PROC(_kern, KERN_BOOTTIME, boottime, CTLTYPE_STRUCT|CTLFLAG_RD, 97 NULL, 0, sysctl_kern_boottime, "S,timeval", "System boottime"); 98 99 SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, ""); 100 SYSCTL_NODE(_kern_timecounter, OID_AUTO, tc, CTLFLAG_RW, 0, ""); 101 102 static int timestepwarnings; 103 SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW, 104 ×tepwarnings, 0, ""); 105 106 static void tc_windup(void); 107 static void cpu_tick_calibrate(int); 108 109 static int 110 sysctl_kern_boottime(SYSCTL_HANDLER_ARGS) 111 { 112 #ifdef SCTL_MASK32 113 int tv[2]; 114 115 if (req->flags & SCTL_MASK32) { 116 tv[0] = boottime.tv_sec; 117 tv[1] = boottime.tv_usec; 118 return SYSCTL_OUT(req, tv, sizeof(tv)); 119 } else 120 #endif 121 return SYSCTL_OUT(req, &boottime, sizeof(boottime)); 122 } 123 124 static int 125 sysctl_kern_timecounter_get(SYSCTL_HANDLER_ARGS) 126 { 127 u_int ncount; 128 struct timecounter *tc = arg1; 129 130 ncount = tc->tc_get_timecount(tc); 131 return sysctl_handle_int(oidp, &ncount, 0, req); 132 } 133 134 static int 135 sysctl_kern_timecounter_freq(SYSCTL_HANDLER_ARGS) 136 { 137 u_int64_t freq; 138 struct timecounter *tc = arg1; 139 140 freq = tc->tc_frequency; 141 return sysctl_handle_quad(oidp, &freq, 0, req); 142 } 143 144 /* 145 * Return the difference between the timehands' counter value now and what 146 * was when we copied it to the timehands' offset_count. 147 */ 148 static __inline u_int 149 tc_delta(struct timehands *th) 150 { 151 struct timecounter *tc; 152 153 tc = th->th_counter; 154 return ((tc->tc_get_timecount(tc) - th->th_offset_count) & 155 tc->tc_counter_mask); 156 } 157 158 /* 159 * Functions for reading the time. We have to loop until we are sure that 160 * the timehands that we operated on was not updated under our feet. See 161 * the comment in <sys/time.h> for a description of these 12 functions. 162 */ 163 164 void 165 binuptime(struct bintime *bt) 166 { 167 struct timehands *th; 168 u_int gen; 169 170 do { 171 th = timehands; 172 gen = th->th_generation; 173 *bt = th->th_offset; 174 bintime_addx(bt, th->th_scale * tc_delta(th)); 175 } while (gen == 0 || gen != th->th_generation); 176 } 177 178 void 179 nanouptime(struct timespec *tsp) 180 { 181 struct bintime bt; 182 183 binuptime(&bt); 184 bintime2timespec(&bt, tsp); 185 } 186 187 void 188 microuptime(struct timeval *tvp) 189 { 190 struct bintime bt; 191 192 binuptime(&bt); 193 bintime2timeval(&bt, tvp); 194 } 195 196 void 197 bintime(struct bintime *bt) 198 { 199 200 binuptime(bt); 201 bintime_add(bt, &boottimebin); 202 } 203 204 void 205 nanotime(struct timespec *tsp) 206 { 207 struct bintime bt; 208 209 bintime(&bt); 210 bintime2timespec(&bt, tsp); 211 } 212 213 void 214 microtime(struct timeval *tvp) 215 { 216 struct bintime bt; 217 218 bintime(&bt); 219 bintime2timeval(&bt, tvp); 220 } 221 222 void 223 getbinuptime(struct bintime *bt) 224 { 225 struct timehands *th; 226 u_int gen; 227 228 do { 229 th = timehands; 230 gen = th->th_generation; 231 *bt = th->th_offset; 232 } while (gen == 0 || gen != th->th_generation); 233 } 234 235 void 236 getnanouptime(struct timespec *tsp) 237 { 238 struct timehands *th; 239 u_int gen; 240 241 do { 242 th = timehands; 243 gen = th->th_generation; 244 bintime2timespec(&th->th_offset, tsp); 245 } while (gen == 0 || gen != th->th_generation); 246 } 247 248 void 249 getmicrouptime(struct timeval *tvp) 250 { 251 struct timehands *th; 252 u_int gen; 253 254 do { 255 th = timehands; 256 gen = th->th_generation; 257 bintime2timeval(&th->th_offset, tvp); 258 } while (gen == 0 || gen != th->th_generation); 259 } 260 261 void 262 getbintime(struct bintime *bt) 263 { 264 struct timehands *th; 265 u_int gen; 266 267 do { 268 th = timehands; 269 gen = th->th_generation; 270 *bt = th->th_offset; 271 } while (gen == 0 || gen != th->th_generation); 272 bintime_add(bt, &boottimebin); 273 } 274 275 void 276 getnanotime(struct timespec *tsp) 277 { 278 struct timehands *th; 279 u_int gen; 280 281 do { 282 th = timehands; 283 gen = th->th_generation; 284 *tsp = th->th_nanotime; 285 } while (gen == 0 || gen != th->th_generation); 286 } 287 288 void 289 getmicrotime(struct timeval *tvp) 290 { 291 struct timehands *th; 292 u_int gen; 293 294 do { 295 th = timehands; 296 gen = th->th_generation; 297 *tvp = th->th_microtime; 298 } while (gen == 0 || gen != th->th_generation); 299 } 300 301 /* 302 * Initialize a new timecounter and possibly use it. 303 */ 304 void 305 tc_init(struct timecounter *tc) 306 { 307 u_int u; 308 struct sysctl_oid *tc_root; 309 310 u = tc->tc_frequency / tc->tc_counter_mask; 311 /* XXX: We need some margin here, 10% is a guess */ 312 u *= 11; 313 u /= 10; 314 if (u > hz && tc->tc_quality >= 0) { 315 tc->tc_quality = -2000; 316 if (bootverbose) { 317 printf("Timecounter \"%s\" frequency %ju Hz", 318 tc->tc_name, (uintmax_t)tc->tc_frequency); 319 printf(" -- Insufficient hz, needs at least %u\n", u); 320 } 321 } else if (tc->tc_quality >= 0 || bootverbose) { 322 printf("Timecounter \"%s\" frequency %ju Hz quality %d\n", 323 tc->tc_name, (uintmax_t)tc->tc_frequency, 324 tc->tc_quality); 325 } 326 327 tc->tc_next = timecounters; 328 timecounters = tc; 329 /* 330 * Set up sysctl tree for this counter. 331 */ 332 tc_root = SYSCTL_ADD_NODE(NULL, 333 SYSCTL_STATIC_CHILDREN(_kern_timecounter_tc), OID_AUTO, tc->tc_name, 334 CTLFLAG_RW, 0, "timecounter description"); 335 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, 336 "mask", CTLFLAG_RD, &(tc->tc_counter_mask), 0, 337 "mask for implemented bits"); 338 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, 339 "counter", CTLTYPE_UINT | CTLFLAG_RD, tc, sizeof(*tc), 340 sysctl_kern_timecounter_get, "IU", "current timecounter value"); 341 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, 342 "frequency", CTLTYPE_QUAD | CTLFLAG_RD, tc, sizeof(*tc), 343 sysctl_kern_timecounter_freq, "QU", "timecounter frequency"); 344 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, 345 "quality", CTLFLAG_RD, &(tc->tc_quality), 0, 346 "goodness of time counter"); 347 /* 348 * Never automatically use a timecounter with negative quality. 349 * Even though we run on the dummy counter, switching here may be 350 * worse since this timecounter may not be monotonous. 351 */ 352 if (tc->tc_quality < 0) 353 return; 354 if (tc->tc_quality < timecounter->tc_quality) 355 return; 356 if (tc->tc_quality == timecounter->tc_quality && 357 tc->tc_frequency < timecounter->tc_frequency) 358 return; 359 (void)tc->tc_get_timecount(tc); 360 (void)tc->tc_get_timecount(tc); 361 timecounter = tc; 362 } 363 364 /* Report the frequency of the current timecounter. */ 365 u_int64_t 366 tc_getfrequency(void) 367 { 368 369 return (timehands->th_counter->tc_frequency); 370 } 371 372 /* 373 * Step our concept of UTC. This is done by modifying our estimate of 374 * when we booted. 375 * XXX: not locked. 376 */ 377 void 378 tc_setclock(struct timespec *ts) 379 { 380 struct timespec tbef, taft; 381 struct bintime bt, bt2; 382 383 cpu_tick_calibrate(1); 384 nanotime(&tbef); 385 timespec2bintime(ts, &bt); 386 binuptime(&bt2); 387 bintime_sub(&bt, &bt2); 388 bintime_add(&bt2, &boottimebin); 389 boottimebin = bt; 390 bintime2timeval(&bt, &boottime); 391 392 /* XXX fiddle all the little crinkly bits around the fiords... */ 393 tc_windup(); 394 nanotime(&taft); 395 if (timestepwarnings) { 396 log(LOG_INFO, 397 "Time stepped from %jd.%09ld to %jd.%09ld (%jd.%09ld)\n", 398 (intmax_t)tbef.tv_sec, tbef.tv_nsec, 399 (intmax_t)taft.tv_sec, taft.tv_nsec, 400 (intmax_t)ts->tv_sec, ts->tv_nsec); 401 } 402 cpu_tick_calibrate(1); 403 } 404 405 /* 406 * Initialize the next struct timehands in the ring and make 407 * it the active timehands. Along the way we might switch to a different 408 * timecounter and/or do seconds processing in NTP. Slightly magic. 409 */ 410 static void 411 tc_windup(void) 412 { 413 struct bintime bt; 414 struct timehands *th, *tho; 415 u_int64_t scale; 416 u_int delta, ncount, ogen; 417 int i; 418 time_t t; 419 420 /* 421 * Make the next timehands a copy of the current one, but do not 422 * overwrite the generation or next pointer. While we update 423 * the contents, the generation must be zero. 424 */ 425 tho = timehands; 426 th = tho->th_next; 427 ogen = th->th_generation; 428 th->th_generation = 0; 429 bcopy(tho, th, offsetof(struct timehands, th_generation)); 430 431 /* 432 * Capture a timecounter delta on the current timecounter and if 433 * changing timecounters, a counter value from the new timecounter. 434 * Update the offset fields accordingly. 435 */ 436 delta = tc_delta(th); 437 if (th->th_counter != timecounter) 438 ncount = timecounter->tc_get_timecount(timecounter); 439 else 440 ncount = 0; 441 th->th_offset_count += delta; 442 th->th_offset_count &= th->th_counter->tc_counter_mask; 443 bintime_addx(&th->th_offset, th->th_scale * delta); 444 445 /* 446 * Hardware latching timecounters may not generate interrupts on 447 * PPS events, so instead we poll them. There is a finite risk that 448 * the hardware might capture a count which is later than the one we 449 * got above, and therefore possibly in the next NTP second which might 450 * have a different rate than the current NTP second. It doesn't 451 * matter in practice. 452 */ 453 if (tho->th_counter->tc_poll_pps) 454 tho->th_counter->tc_poll_pps(tho->th_counter); 455 456 /* 457 * Deal with NTP second processing. The for loop normally 458 * iterates at most once, but in extreme situations it might 459 * keep NTP sane if timeouts are not run for several seconds. 460 * At boot, the time step can be large when the TOD hardware 461 * has been read, so on really large steps, we call 462 * ntp_update_second only twice. We need to call it twice in 463 * case we missed a leap second. 464 */ 465 bt = th->th_offset; 466 bintime_add(&bt, &boottimebin); 467 i = bt.sec - tho->th_microtime.tv_sec; 468 if (i > LARGE_STEP) 469 i = 2; 470 for (; i > 0; i--) { 471 t = bt.sec; 472 ntp_update_second(&th->th_adjustment, &bt.sec); 473 if (bt.sec != t) 474 boottimebin.sec += bt.sec - t; 475 } 476 /* Update the UTC timestamps used by the get*() functions. */ 477 /* XXX shouldn't do this here. Should force non-`get' versions. */ 478 bintime2timeval(&bt, &th->th_microtime); 479 bintime2timespec(&bt, &th->th_nanotime); 480 481 /* Now is a good time to change timecounters. */ 482 if (th->th_counter != timecounter) { 483 th->th_counter = timecounter; 484 th->th_offset_count = ncount; 485 } 486 487 /*- 488 * Recalculate the scaling factor. We want the number of 1/2^64 489 * fractions of a second per period of the hardware counter, taking 490 * into account the th_adjustment factor which the NTP PLL/adjtime(2) 491 * processing provides us with. 492 * 493 * The th_adjustment is nanoseconds per second with 32 bit binary 494 * fraction and we want 64 bit binary fraction of second: 495 * 496 * x = a * 2^32 / 10^9 = a * 4.294967296 497 * 498 * The range of th_adjustment is +/- 5000PPM so inside a 64bit int 499 * we can only multiply by about 850 without overflowing, that 500 * leaves no suitably precise fractions for multiply before divide. 501 * 502 * Divide before multiply with a fraction of 2199/512 results in a 503 * systematic undercompensation of 10PPM of th_adjustment. On a 504 * 5000PPM adjustment this is a 0.05PPM error. This is acceptable. 505 * 506 * We happily sacrifice the lowest of the 64 bits of our result 507 * to the goddess of code clarity. 508 * 509 */ 510 scale = (u_int64_t)1 << 63; 511 scale += (th->th_adjustment / 1024) * 2199; 512 scale /= th->th_counter->tc_frequency; 513 th->th_scale = scale * 2; 514 515 /* 516 * Now that the struct timehands is again consistent, set the new 517 * generation number, making sure to not make it zero. 518 */ 519 if (++ogen == 0) 520 ogen = 1; 521 th->th_generation = ogen; 522 523 /* Go live with the new struct timehands. */ 524 time_second = th->th_microtime.tv_sec; 525 time_uptime = th->th_offset.sec; 526 timehands = th; 527 } 528 529 /* Report or change the active timecounter hardware. */ 530 static int 531 sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS) 532 { 533 char newname[32]; 534 struct timecounter *newtc, *tc; 535 int error; 536 537 tc = timecounter; 538 strlcpy(newname, tc->tc_name, sizeof(newname)); 539 540 error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req); 541 if (error != 0 || req->newptr == NULL || 542 strcmp(newname, tc->tc_name) == 0) 543 return (error); 544 for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) { 545 if (strcmp(newname, newtc->tc_name) != 0) 546 continue; 547 548 /* Warm up new timecounter. */ 549 (void)newtc->tc_get_timecount(newtc); 550 (void)newtc->tc_get_timecount(newtc); 551 552 timecounter = newtc; 553 return (0); 554 } 555 return (EINVAL); 556 } 557 558 SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING | CTLFLAG_RW, 559 0, 0, sysctl_kern_timecounter_hardware, "A", ""); 560 561 562 /* Report or change the active timecounter hardware. */ 563 static int 564 sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS) 565 { 566 char buf[32], *spc; 567 struct timecounter *tc; 568 int error; 569 570 spc = ""; 571 error = 0; 572 for (tc = timecounters; error == 0 && tc != NULL; tc = tc->tc_next) { 573 sprintf(buf, "%s%s(%d)", 574 spc, tc->tc_name, tc->tc_quality); 575 error = SYSCTL_OUT(req, buf, strlen(buf)); 576 spc = " "; 577 } 578 return (error); 579 } 580 581 SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice, CTLTYPE_STRING | CTLFLAG_RD, 582 0, 0, sysctl_kern_timecounter_choice, "A", ""); 583 584 /* 585 * RFC 2783 PPS-API implementation. 586 */ 587 588 int 589 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps) 590 { 591 pps_params_t *app; 592 struct pps_fetch_args *fapi; 593 #ifdef PPS_SYNC 594 struct pps_kcbind_args *kapi; 595 #endif 596 597 KASSERT(pps != NULL, ("NULL pps pointer in pps_ioctl")); 598 switch (cmd) { 599 case PPS_IOC_CREATE: 600 return (0); 601 case PPS_IOC_DESTROY: 602 return (0); 603 case PPS_IOC_SETPARAMS: 604 app = (pps_params_t *)data; 605 if (app->mode & ~pps->ppscap) 606 return (EINVAL); 607 pps->ppsparam = *app; 608 return (0); 609 case PPS_IOC_GETPARAMS: 610 app = (pps_params_t *)data; 611 *app = pps->ppsparam; 612 app->api_version = PPS_API_VERS_1; 613 return (0); 614 case PPS_IOC_GETCAP: 615 *(int*)data = pps->ppscap; 616 return (0); 617 case PPS_IOC_FETCH: 618 fapi = (struct pps_fetch_args *)data; 619 if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC) 620 return (EINVAL); 621 if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec) 622 return (EOPNOTSUPP); 623 pps->ppsinfo.current_mode = pps->ppsparam.mode; 624 fapi->pps_info_buf = pps->ppsinfo; 625 return (0); 626 case PPS_IOC_KCBIND: 627 #ifdef PPS_SYNC 628 kapi = (struct pps_kcbind_args *)data; 629 /* XXX Only root should be able to do this */ 630 if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC) 631 return (EINVAL); 632 if (kapi->kernel_consumer != PPS_KC_HARDPPS) 633 return (EINVAL); 634 if (kapi->edge & ~pps->ppscap) 635 return (EINVAL); 636 pps->kcmode = kapi->edge; 637 return (0); 638 #else 639 return (EOPNOTSUPP); 640 #endif 641 default: 642 return (ENOIOCTL); 643 } 644 } 645 646 void 647 pps_init(struct pps_state *pps) 648 { 649 pps->ppscap |= PPS_TSFMT_TSPEC; 650 if (pps->ppscap & PPS_CAPTUREASSERT) 651 pps->ppscap |= PPS_OFFSETASSERT; 652 if (pps->ppscap & PPS_CAPTURECLEAR) 653 pps->ppscap |= PPS_OFFSETCLEAR; 654 } 655 656 void 657 pps_capture(struct pps_state *pps) 658 { 659 struct timehands *th; 660 661 KASSERT(pps != NULL, ("NULL pps pointer in pps_capture")); 662 th = timehands; 663 pps->capgen = th->th_generation; 664 pps->capth = th; 665 pps->capcount = th->th_counter->tc_get_timecount(th->th_counter); 666 if (pps->capgen != th->th_generation) 667 pps->capgen = 0; 668 } 669 670 void 671 pps_event(struct pps_state *pps, int event) 672 { 673 struct bintime bt; 674 struct timespec ts, *tsp, *osp; 675 u_int tcount, *pcount; 676 int foff, fhard; 677 pps_seq_t *pseq; 678 679 KASSERT(pps != NULL, ("NULL pps pointer in pps_event")); 680 /* If the timecounter was wound up underneath us, bail out. */ 681 if (pps->capgen == 0 || pps->capgen != pps->capth->th_generation) 682 return; 683 684 /* Things would be easier with arrays. */ 685 if (event == PPS_CAPTUREASSERT) { 686 tsp = &pps->ppsinfo.assert_timestamp; 687 osp = &pps->ppsparam.assert_offset; 688 foff = pps->ppsparam.mode & PPS_OFFSETASSERT; 689 fhard = pps->kcmode & PPS_CAPTUREASSERT; 690 pcount = &pps->ppscount[0]; 691 pseq = &pps->ppsinfo.assert_sequence; 692 } else { 693 tsp = &pps->ppsinfo.clear_timestamp; 694 osp = &pps->ppsparam.clear_offset; 695 foff = pps->ppsparam.mode & PPS_OFFSETCLEAR; 696 fhard = pps->kcmode & PPS_CAPTURECLEAR; 697 pcount = &pps->ppscount[1]; 698 pseq = &pps->ppsinfo.clear_sequence; 699 } 700 701 /* 702 * If the timecounter changed, we cannot compare the count values, so 703 * we have to drop the rest of the PPS-stuff until the next event. 704 */ 705 if (pps->ppstc != pps->capth->th_counter) { 706 pps->ppstc = pps->capth->th_counter; 707 *pcount = pps->capcount; 708 pps->ppscount[2] = pps->capcount; 709 return; 710 } 711 712 /* Convert the count to a timespec. */ 713 tcount = pps->capcount - pps->capth->th_offset_count; 714 tcount &= pps->capth->th_counter->tc_counter_mask; 715 bt = pps->capth->th_offset; 716 bintime_addx(&bt, pps->capth->th_scale * tcount); 717 bintime_add(&bt, &boottimebin); 718 bintime2timespec(&bt, &ts); 719 720 /* If the timecounter was wound up underneath us, bail out. */ 721 if (pps->capgen != pps->capth->th_generation) 722 return; 723 724 *pcount = pps->capcount; 725 (*pseq)++; 726 *tsp = ts; 727 728 if (foff) { 729 timespecadd(tsp, osp); 730 if (tsp->tv_nsec < 0) { 731 tsp->tv_nsec += 1000000000; 732 tsp->tv_sec -= 1; 733 } 734 } 735 #ifdef PPS_SYNC 736 if (fhard) { 737 u_int64_t scale; 738 739 /* 740 * Feed the NTP PLL/FLL. 741 * The FLL wants to know how many (hardware) nanoseconds 742 * elapsed since the previous event. 743 */ 744 tcount = pps->capcount - pps->ppscount[2]; 745 pps->ppscount[2] = pps->capcount; 746 tcount &= pps->capth->th_counter->tc_counter_mask; 747 scale = (u_int64_t)1 << 63; 748 scale /= pps->capth->th_counter->tc_frequency; 749 scale *= 2; 750 bt.sec = 0; 751 bt.frac = 0; 752 bintime_addx(&bt, scale * tcount); 753 bintime2timespec(&bt, &ts); 754 hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec); 755 } 756 #endif 757 } 758 759 /* 760 * Timecounters need to be updated every so often to prevent the hardware 761 * counter from overflowing. Updating also recalculates the cached values 762 * used by the get*() family of functions, so their precision depends on 763 * the update frequency. 764 */ 765 766 static int tc_tick; 767 SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0, ""); 768 769 void 770 tc_ticktock(void) 771 { 772 static int count; 773 static time_t last_calib; 774 775 if (++count < tc_tick) 776 return; 777 count = 0; 778 tc_windup(); 779 if (time_uptime != last_calib && !(time_uptime & 0xf)) { 780 cpu_tick_calibrate(0); 781 last_calib = time_uptime; 782 } 783 } 784 785 static void 786 inittimecounter(void *dummy) 787 { 788 u_int p; 789 790 /* 791 * Set the initial timeout to 792 * max(1, <approx. number of hardclock ticks in a millisecond>). 793 * People should probably not use the sysctl to set the timeout 794 * to smaller than its inital value, since that value is the 795 * smallest reasonable one. If they want better timestamps they 796 * should use the non-"get"* functions. 797 */ 798 if (hz > 1000) 799 tc_tick = (hz + 500) / 1000; 800 else 801 tc_tick = 1; 802 p = (tc_tick * 1000000) / hz; 803 printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000); 804 805 /* warm up new timecounter (again) and get rolling. */ 806 (void)timecounter->tc_get_timecount(timecounter); 807 (void)timecounter->tc_get_timecount(timecounter); 808 } 809 810 SYSINIT(timecounter, SI_SUB_CLOCKS, SI_ORDER_SECOND, inittimecounter, NULL); 811 812 /* Cpu tick handling -------------------------------------------------*/ 813 814 static int cpu_tick_variable; 815 static uint64_t cpu_tick_frequency; 816 817 static uint64_t 818 tc_cpu_ticks(void) 819 { 820 static uint64_t base; 821 static unsigned last; 822 unsigned u; 823 struct timecounter *tc; 824 825 tc = timehands->th_counter; 826 u = tc->tc_get_timecount(tc) & tc->tc_counter_mask; 827 if (u < last) 828 base += (uint64_t)tc->tc_counter_mask + 1; 829 last = u; 830 return (u + base); 831 } 832 833 /* 834 * This function gets called every 16 seconds on only one designated 835 * CPU in the system from hardclock() via tc_ticktock(). 836 * 837 * Whenever the real time clock is stepped we get called with reset=1 838 * to make sure we handle suspend/resume and similar events correctly. 839 */ 840 841 static void 842 cpu_tick_calibrate(int reset) 843 { 844 static uint64_t c_last; 845 uint64_t c_this, c_delta; 846 static struct bintime t_last; 847 struct bintime t_this, t_delta; 848 uint32_t divi; 849 850 if (reset) { 851 /* The clock was stepped, abort & reset */ 852 t_last.sec = 0; 853 return; 854 } 855 856 /* we don't calibrate fixed rate cputicks */ 857 if (!cpu_tick_variable) 858 return; 859 860 getbinuptime(&t_this); 861 c_this = cpu_ticks(); 862 if (t_last.sec != 0) { 863 c_delta = c_this - c_last; 864 t_delta = t_this; 865 bintime_sub(&t_delta, &t_last); 866 /* 867 * Validate that 16 +/- 1/256 seconds passed. 868 * After division by 16 this gives us a precision of 869 * roughly 250PPM which is sufficient 870 */ 871 if (t_delta.sec > 16 || ( 872 t_delta.sec == 16 && t_delta.frac >= (0x01LL << 56))) { 873 /* too long */ 874 if (bootverbose) 875 printf("t_delta %ju.%016jx too long\n", 876 (uintmax_t)t_delta.sec, 877 (uintmax_t)t_delta.frac); 878 } else if (t_delta.sec < 15 || 879 (t_delta.sec == 15 && t_delta.frac <= (0xffLL << 56))) { 880 /* too short */ 881 if (bootverbose) 882 printf("t_delta %ju.%016jx too short\n", 883 (uintmax_t)t_delta.sec, 884 (uintmax_t)t_delta.frac); 885 } else { 886 /* just right */ 887 /* 888 * Headroom: 889 * 2^(64-20) / 16[s] = 890 * 2^(44) / 16[s] = 891 * 17.592.186.044.416 / 16 = 892 * 1.099.511.627.776 [Hz] 893 */ 894 divi = t_delta.sec << 20; 895 divi |= t_delta.frac >> (64 - 20); 896 c_delta <<= 20; 897 c_delta /= divi; 898 if (c_delta > cpu_tick_frequency) { 899 if (0 && bootverbose) 900 printf("cpu_tick increased to %ju Hz\n", 901 c_delta); 902 cpu_tick_frequency = c_delta; 903 } 904 } 905 } 906 c_last = c_this; 907 t_last = t_this; 908 } 909 910 void 911 set_cputicker(cpu_tick_f *func, uint64_t freq, unsigned var) 912 { 913 914 if (func == NULL) { 915 cpu_ticks = tc_cpu_ticks; 916 } else { 917 cpu_tick_frequency = freq; 918 cpu_tick_variable = var; 919 cpu_ticks = func; 920 } 921 } 922 923 uint64_t 924 cpu_tickrate(void) 925 { 926 927 if (cpu_ticks == tc_cpu_ticks) 928 return (tc_getfrequency()); 929 return (cpu_tick_frequency); 930 } 931 932 /* 933 * We need to be slightly careful converting cputicks to microseconds. 934 * There is plenty of margin in 64 bits of microseconds (half a million 935 * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply 936 * before divide conversion (to retain precision) we find that the 937 * margin shrinks to 1.5 hours (one millionth of 146y). 938 * With a three prong approach we never lose significant bits, no 939 * matter what the cputick rate and length of timeinterval is. 940 */ 941 942 uint64_t 943 cputick2usec(uint64_t tick) 944 { 945 946 if (tick > 18446744073709551LL) /* floor(2^64 / 1000) */ 947 return (tick / (cpu_tickrate() / 1000000LL)); 948 else if (tick > 18446744073709LL) /* floor(2^64 / 1000000) */ 949 return ((tick * 1000LL) / (cpu_tickrate() / 1000LL)); 950 else 951 return ((tick * 1000000LL) / cpu_tickrate()); 952 } 953 954 cpu_tick_f *cpu_ticks = tc_cpu_ticks; 955