kern_todr.c revision 1.48
1 /* $NetBSD: kern_todr.c,v 1.48 2025/09/07 14:31:58 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 2020 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 1988 University of Utah. 34 * Copyright (c) 1992, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * This code is derived from software contributed to Berkeley by 38 * the Systems Programming Group of the University of Utah Computer 39 * Science Department and Ralph Campbell. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 3. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 * 65 * from: Utah Hdr: clock.c 1.18 91/01/21 66 * 67 * @(#)clock.c 8.1 (Berkeley) 6/10/93 68 */ 69 70 #include "opt_todr.h" 71 72 #include <sys/cdefs.h> 73 __KERNEL_RCSID(0, "$NetBSD: kern_todr.c,v 1.48 2025/09/07 14:31:58 thorpej Exp $"); 74 75 #include <sys/param.h> 76 #include <sys/kernel.h> 77 #include <sys/systm.h> 78 #include <sys/device.h> 79 #include <sys/timetc.h> 80 #include <sys/intr.h> 81 #include <sys/rndsource.h> 82 #include <sys/mutex.h> 83 84 #include <dev/clock_subr.h> /* hmm.. this should probably move to sys */ 85 86 static int todr_gettime(todr_chip_handle_t, struct timeval *); 87 static int todr_settime(todr_chip_handle_t, struct timeval *); 88 89 static kmutex_t todr_mutex; 90 static todr_chip_handle_t todr_handle; 91 static bool todr_initialized; 92 93 /* The minimum reasonable RTC date before preposterousness */ 94 #define PREPOSTEROUS_YEARS (2021 - POSIX_BASE_YEAR) 95 96 /* 97 * todr_init: 98 * Initialize TOD clock data. 99 */ 100 void 101 todr_init(void) 102 { 103 104 mutex_init(&todr_mutex, MUTEX_DEFAULT, IPL_NONE); 105 todr_initialized = true; 106 } 107 108 /* 109 * todr_lock: 110 * Acquire the TODR lock. 111 */ 112 void 113 todr_lock(void) 114 { 115 116 mutex_enter(&todr_mutex); 117 } 118 119 /* 120 * todr_unlock: 121 * Release the TODR lock. 122 */ 123 void 124 todr_unlock(void) 125 { 126 127 mutex_exit(&todr_mutex); 128 } 129 130 /* 131 * todr_lock_owned: 132 * Return true if the current thread owns the TODR lock. 133 * This is to be used by diagnostic assertions only. 134 */ 135 bool 136 todr_lock_owned(void) 137 { 138 139 return mutex_owned(&todr_mutex) ? true : false; 140 } 141 142 /* 143 * todr_attach: 144 * Attach the clock device to todr_handle. 145 */ 146 void 147 todr_attach(todr_chip_handle_t todr) 148 { 149 150 /* 151 * todr_init() is called very early in main(), but this is 152 * here to catch a case where todr_attach() is called before 153 * main(). 154 */ 155 KASSERT(todr_initialized); 156 157 todr_lock(); 158 if (todr_handle) { 159 todr_unlock(); 160 printf("todr_attach: TOD already configured\n"); 161 return; 162 } 163 todr_handle = todr; 164 todr_unlock(); 165 } 166 167 static bool timeset = false; 168 169 /* 170 * todr_set_systime: 171 * Set up the system's time. The "base" argument is a best-guess 172 * close-enough value to use if the TOD clock is unavailable or 173 * contains garbage. Must be called with the TODR lock held. 174 */ 175 void 176 todr_set_systime(time_t base) 177 { 178 bool badbase = false; 179 bool waszero = (base == 0); 180 bool goodtime = false; 181 bool badrtc = false; 182 struct timespec ts; 183 struct timeval tv; 184 185 KASSERT(todr_lock_owned()); 186 187 rnd_add_data(NULL, &base, sizeof(base), 0); 188 189 if (base < 5 * SECS_PER_COMMON_YEAR) { 190 struct clock_ymdhms basedate; 191 192 /* 193 * If base is 0, assume filesystem time is just unknown 194 * instead of preposterous. Don't bark. 195 */ 196 if (base != 0) 197 printf("WARNING: preposterous time in file system\n"); 198 /* not going to use it anyway, if the chip is readable */ 199 basedate.dt_year = 2010; 200 basedate.dt_mon = 1; 201 basedate.dt_day = 1; 202 basedate.dt_hour = 12; 203 basedate.dt_min = 0; 204 basedate.dt_sec = 0; 205 base = clock_ymdhms_to_secs(&basedate); 206 badbase = true; 207 } 208 209 /* 210 * Some ports need to be supplied base in order to fabricate a time_t. 211 */ 212 if (todr_handle) 213 todr_handle->todr_base_time = base; 214 215 memset(&tv, 0, sizeof(tv)); 216 217 if ((todr_handle == NULL) || 218 (todr_gettime(todr_handle, &tv) != 0) || 219 (tv.tv_sec < (PREPOSTEROUS_YEARS * SECS_PER_COMMON_YEAR))) { 220 221 if (todr_handle != NULL) 222 printf("WARNING: preposterous TOD clock time\n"); 223 else 224 printf("WARNING: no TOD clock present\n"); 225 badrtc = true; 226 } else { 227 time_t deltat = tv.tv_sec - base; 228 229 if (deltat < 0) 230 deltat = -deltat; 231 232 if (!badbase && deltat >= 2 * SECS_PER_DAY) { 233 234 if (tv.tv_sec < base) { 235 /* 236 * The clock should never go backwards 237 * relative to filesystem time. If it 238 * does by more than the threshold, 239 * believe the filesystem. 240 */ 241 printf("WARNING: clock lost %" PRId64 " days\n", 242 deltat / SECS_PER_DAY); 243 badrtc = true; 244 } else { 245 aprint_verbose("WARNING: clock gained %" PRId64 246 " days\n", deltat / SECS_PER_DAY); 247 goodtime = true; 248 } 249 } else { 250 goodtime = true; 251 } 252 253 rnd_add_data(NULL, &tv, sizeof(tv), 0); 254 } 255 256 /* if the rtc time is bad, use the filesystem time */ 257 if (badrtc) { 258 if (badbase) { 259 printf("WARNING: using default initial time\n"); 260 } else { 261 printf("WARNING: using filesystem time\n"); 262 } 263 tv.tv_sec = base; 264 tv.tv_usec = 0; 265 } 266 267 timeset = true; 268 269 ts.tv_sec = tv.tv_sec; 270 ts.tv_nsec = tv.tv_usec * 1000; 271 tc_setclock(&ts); 272 273 if (waszero || goodtime) 274 return; 275 276 printf("WARNING: CHECK AND RESET THE DATE!\n"); 277 } 278 279 /* 280 * todr_save_systime: 281 * Save the current system time back to the TOD clock. 282 * Must be called with the TODR lock held. 283 */ 284 void 285 todr_save_systime(void) 286 { 287 struct timeval tv; 288 289 KASSERT(todr_lock_owned()); 290 291 /* 292 * We might have been called by boot() due to a crash early 293 * on. Don't reset the clock chip if we don't know what time 294 * it is. 295 */ 296 if (!timeset) 297 return; 298 299 getmicrotime(&tv); 300 301 if (tv.tv_sec == 0) 302 return; 303 304 if (todr_handle) 305 if (todr_settime(todr_handle, &tv) != 0) 306 printf("Cannot set TOD clock time\n"); 307 } 308 309 /* 310 * inittodr: 311 * Legacy wrapper around todr_set_systime(). 312 */ 313 void 314 inittodr(time_t base) 315 { 316 317 todr_lock(); 318 todr_set_systime(base); 319 todr_unlock(); 320 } 321 322 /* 323 * resettodr: 324 * Legacy wrapper around todr_save_systime(). 325 */ 326 void 327 resettodr(void) 328 { 329 330 /* 331 * If we're shutting down, we don't want to get stuck in case 332 * someone was already fiddling with the TOD clock. 333 */ 334 if (shutting_down) { 335 if (mutex_tryenter(&todr_mutex) == 0) { 336 printf("WARNING: Cannot set TOD clock time (busy)\n"); 337 return; 338 } 339 } else { 340 todr_lock(); 341 } 342 todr_save_systime(); 343 todr_unlock(); 344 } 345 346 #ifdef TODR_DEBUG 347 static void 348 todr_debug(const char *prefix, int rv, struct clock_ymdhms *dt, 349 struct timeval *tvp) 350 { 351 struct timeval tv_val; 352 struct clock_ymdhms dt_val; 353 354 if (dt == NULL) { 355 clock_secs_to_ymdhms(tvp->tv_sec, &dt_val); 356 dt = &dt_val; 357 } 358 if (tvp == NULL) { 359 tvp = &tv_val; 360 tvp->tv_sec = clock_ymdhms_to_secs(dt); 361 tvp->tv_usec = 0; 362 } 363 printf("%s: rv = %d\n", prefix, rv); 364 printf("%s: rtc_offset = %d\n", prefix, rtc_offset); 365 printf("%s: %4u/%02u/%02u %02u:%02u:%02u, (wday %d) (epoch %u.%06u)\n", 366 prefix, 367 (unsigned)dt->dt_year, dt->dt_mon, dt->dt_day, 368 dt->dt_hour, dt->dt_min, dt->dt_sec, 369 dt->dt_wday, (unsigned)tvp->tv_sec, (unsigned)tvp->tv_usec); 370 } 371 #else /* !TODR_DEBUG */ 372 #define todr_debug(prefix, rv, dt, tvp) 373 #endif /* TODR_DEBUG */ 374 375 static int 376 todr_wenable(todr_chip_handle_t todr, int onoff) 377 { 378 379 if (todr->todr_setwen != NULL) 380 return todr->todr_setwen(todr, onoff); 381 382 return 0; 383 } 384 385 #define ENABLE_TODR_WRITES() \ 386 do { \ 387 if ((rv = todr_wenable(tch, 1)) != 0) { \ 388 printf("%s: cannot enable TODR writes\n", __func__); \ 389 return rv; \ 390 } \ 391 } while (/*CONSTCOND*/0) 392 393 #define DISABLE_TODR_WRITES() \ 394 do { \ 395 if (todr_wenable(tch, 0) != 0) \ 396 printf("%s: WARNING: cannot disable TODR writes\n", \ 397 __func__); \ 398 } while (/*CONSTCOND*/0) 399 400 static int 401 todr_gettime(todr_chip_handle_t tch, struct timeval *tvp) 402 { 403 int rv; 404 405 /* 406 * Write-enable is used even when reading the TODR because 407 * writing to registers may be required in order to do so. 408 */ 409 410 if (tch->todr_gettime) { 411 ENABLE_TODR_WRITES(); 412 rv = tch->todr_gettime(tch, tvp); 413 DISABLE_TODR_WRITES(); 414 /* 415 * Some unconverted ports have their own references to 416 * rtc_offset. A converted port must not do that. 417 */ 418 if (rv == 0) 419 tvp->tv_sec += rtc_offset * 60; 420 todr_debug("TODR-GET-SECS", rv, NULL, tvp); 421 return rv; 422 } else if (tch->todr_gettime_ymdhms) { 423 struct clock_ymdhms dt = { 0 }; 424 ENABLE_TODR_WRITES(); 425 rv = tch->todr_gettime_ymdhms(tch, &dt); 426 DISABLE_TODR_WRITES(); 427 todr_debug("TODR-GET-YMDHMS", rv, &dt, NULL); 428 if (rv) 429 return rv; 430 431 /* 432 * Simple sanity checks. Note that this includes a 433 * value for clocks that can return a leap second. 434 * Note that we don't support double leap seconds, 435 * since this was apparently an error/misunderstanding 436 * on the part of the ISO C committee, and can never 437 * actually occur. If your clock issues us a double 438 * leap second, it must be broken. Ultimately, you'd 439 * have to be trying to read time at precisely that 440 * instant to even notice, so even broken clocks will 441 * work the vast majority of the time. In such a case 442 * it is recommended correction be applied in the 443 * clock driver. 444 */ 445 if (dt.dt_mon < 1 || dt.dt_mon > 12 || 446 dt.dt_day < 1 || dt.dt_day > 31 || 447 dt.dt_hour > 23 || dt.dt_min > 59 || dt.dt_sec > 60) { 448 return EINVAL; 449 } 450 tvp->tv_sec = clock_ymdhms_to_secs(&dt) + rtc_offset * 60; 451 tvp->tv_usec = 0; 452 return tvp->tv_sec < 0 ? EINVAL : 0; 453 } 454 455 return ENXIO; 456 } 457 458 static int 459 todr_settime(todr_chip_handle_t tch, struct timeval *tvp) 460 { 461 int rv; 462 463 if (tch->todr_settime) { 464 struct timeval copy = *tvp; 465 copy.tv_sec -= rtc_offset * 60; 466 ENABLE_TODR_WRITES(); 467 rv = tch->todr_settime(tch, ©); 468 DISABLE_TODR_WRITES(); 469 todr_debug("TODR-SET-SECS", rv, NULL, tvp); 470 return rv; 471 } else if (tch->todr_settime_ymdhms) { 472 struct clock_ymdhms dt; 473 time_t sec = tvp->tv_sec - rtc_offset * 60; 474 if (tvp->tv_usec >= 500000) 475 sec++; 476 clock_secs_to_ymdhms(sec, &dt); 477 ENABLE_TODR_WRITES(); 478 rv = tch->todr_settime_ymdhms(tch, &dt); 479 DISABLE_TODR_WRITES(); 480 todr_debug("TODR-SET-YMDHMS", rv, &dt, NULL); 481 return rv; 482 } 483 484 return ENXIO; 485 } 486
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