1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1988 University of Utah. 5 * Copyright (c) 1982, 1990, 1993 6 * The Regents of the University of California. 7 * Copyright (c) 2011 The FreeBSD Foundation 8 * All rights reserved. 9 * 10 * This code is derived from software contributed to Berkeley by 11 * the Systems Programming Group of the University of Utah Computer 12 * Science Department. 13 * 14 * Portions of this software were developed by Julien Ridoux at the University 15 * of Melbourne under sponsorship from the FreeBSD Foundation. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 3. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * from: Utah $Hdr: clock.c 1.18 91/01/21$ 42 * from: @(#)clock.c 8.2 (Berkeley) 1/12/94 43 * from: NetBSD: clock_subr.c,v 1.6 2001/07/07 17:04:02 thorpej Exp 44 * and 45 * from: src/sys/i386/isa/clock.c,v 1.176 2001/09/04 46 */ 47 48 /* 49 * Helpers for time-of-day clocks. This is useful for architectures that need 50 * support multiple models of such clocks, and generally serves to make the 51 * code more machine-independent. 52 * If the clock in question can also be used as a time counter, the driver 53 * needs to initiate this. 54 * This code is not yet used by all architectures. 55 */ 56 57 #include <sys/cdefs.h> 58 __FBSDID("$FreeBSD$"); 59 60 #include "opt_ffclock.h" 61 62 #include <sys/param.h> 63 #include <sys/systm.h> 64 #include <sys/kernel.h> 65 #include <sys/bus.h> 66 #include <sys/clock.h> 67 #include <sys/lock.h> 68 #include <sys/malloc.h> 69 #include <sys/sx.h> 70 #include <sys/sysctl.h> 71 #include <sys/taskqueue.h> 72 #ifdef FFCLOCK 73 #include <sys/timeffc.h> 74 #endif 75 #include <sys/timetc.h> 76 77 #include "clock_if.h" 78 79 static int show_io; 80 SYSCTL_INT(_debug, OID_AUTO, clock_show_io, CTLFLAG_RWTUN, &show_io, 0, 81 "Enable debug printing of RTC clock I/O; 1=reads, 2=writes, 3=both."); 82 83 static int sysctl_clock_do_io(SYSCTL_HANDLER_ARGS); 84 SYSCTL_PROC(_debug, OID_AUTO, clock_do_io, 85 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0, sysctl_clock_do_io, "I", 86 "Trigger one-time IO on RTC clocks; 1=read (and discard), 2=write"); 87 88 /* XXX: should be kern. now, it's no longer machdep. */ 89 static int disable_rtc_set; 90 SYSCTL_INT(_machdep, OID_AUTO, disable_rtc_set, CTLFLAG_RW, &disable_rtc_set, 91 0, "Disallow adjusting time-of-day clock"); 92 93 /* 94 * An instance of a realtime clock. A list of these tracks all the registered 95 * clocks in the system. 96 * 97 * The resadj member is used to apply a "resolution adjustment" equal to half 98 * the clock's resolution, which is useful mainly on clocks with a whole-second 99 * resolution. Because the clock truncates the fractional part, adding half the 100 * resolution performs 4/5 rounding. The same adjustment is applied to the 101 * times returned from clock_gettime(), because the fraction returned will 102 * always be zero, but on average the actual fraction at the time of the call 103 * should be about .5. 104 */ 105 struct rtc_instance { 106 device_t clockdev; 107 int resolution; 108 int flags; 109 u_int schedns; 110 struct timespec resadj; 111 struct timeout_task 112 stask; 113 LIST_ENTRY(rtc_instance) 114 rtc_entries; 115 }; 116 117 /* 118 * Clocks are updated using a task running on taskqueue_thread. 119 */ 120 static void settime_task_func(void *arg, int pending); 121 122 /* 123 * Registered clocks are kept in a list which is sorted by resolution; the more 124 * accurate clocks get the first shot at providing the time. 125 */ 126 LIST_HEAD(rtc_listhead, rtc_instance); 127 static struct rtc_listhead rtc_list = LIST_HEAD_INITIALIZER(rtc_list); 128 static struct sx rtc_list_lock; 129 SX_SYSINIT(rtc_list_lock_init, &rtc_list_lock, "rtc list"); 130 131 /* 132 * On the task thread, invoke the clock_settime() method of the clock. Do so 133 * holding no locks, so that clock drivers are free to do whatever kind of 134 * locking or sleeping they need to. 135 */ 136 static void 137 settime_task_func(void *arg, int pending) 138 { 139 struct timespec ts; 140 struct rtc_instance *rtc; 141 int error; 142 143 rtc = arg; 144 if (!(rtc->flags & CLOCKF_SETTIME_NO_TS)) { 145 getnanotime(&ts); 146 if (!(rtc->flags & CLOCKF_SETTIME_NO_ADJ)) { 147 ts.tv_sec -= utc_offset(); 148 timespecadd(&ts, &rtc->resadj, &ts); 149 } 150 } else { 151 ts.tv_sec = 0; 152 ts.tv_nsec = 0; 153 } 154 error = CLOCK_SETTIME(rtc->clockdev, &ts); 155 if (error != 0 && bootverbose) 156 device_printf(rtc->clockdev, "CLOCK_SETTIME error %d\n", error); 157 } 158 159 static void 160 clock_dbgprint_hdr(device_t dev, int rw) 161 { 162 struct timespec now; 163 164 getnanotime(&now); 165 device_printf(dev, "%s at ", (rw & CLOCK_DBG_READ) ? "read " : "write"); 166 clock_print_ts(&now, 9); 167 printf(": "); 168 } 169 170 void 171 clock_dbgprint_bcd(device_t dev, int rw, const struct bcd_clocktime *bct) 172 { 173 174 if (show_io & rw) { 175 clock_dbgprint_hdr(dev, rw); 176 clock_print_bcd(bct, 9); 177 printf("\n"); 178 } 179 } 180 181 void 182 clock_dbgprint_ct(device_t dev, int rw, const struct clocktime *ct) 183 { 184 185 if (show_io & rw) { 186 clock_dbgprint_hdr(dev, rw); 187 clock_print_ct(ct, 9); 188 printf("\n"); 189 } 190 } 191 192 void 193 clock_dbgprint_err(device_t dev, int rw, int err) 194 { 195 196 if (show_io & rw) { 197 clock_dbgprint_hdr(dev, rw); 198 printf("error = %d\n", err); 199 } 200 } 201 202 void 203 clock_dbgprint_ts(device_t dev, int rw, const struct timespec *ts) 204 { 205 206 if (show_io & rw) { 207 clock_dbgprint_hdr(dev, rw); 208 clock_print_ts(ts, 9); 209 printf("\n"); 210 } 211 } 212 213 void 214 clock_register_flags(device_t clockdev, long resolution, int flags) 215 { 216 struct rtc_instance *rtc, *newrtc; 217 218 newrtc = malloc(sizeof(*newrtc), M_DEVBUF, M_WAITOK); 219 newrtc->clockdev = clockdev; 220 newrtc->resolution = (int)resolution; 221 newrtc->flags = flags; 222 newrtc->schedns = 0; 223 newrtc->resadj.tv_sec = newrtc->resolution / 2 / 1000000; 224 newrtc->resadj.tv_nsec = newrtc->resolution / 2 % 1000000 * 1000; 225 TIMEOUT_TASK_INIT(taskqueue_thread, &newrtc->stask, 0, 226 settime_task_func, newrtc); 227 228 sx_xlock(&rtc_list_lock); 229 if (LIST_EMPTY(&rtc_list)) { 230 LIST_INSERT_HEAD(&rtc_list, newrtc, rtc_entries); 231 } else { 232 LIST_FOREACH(rtc, &rtc_list, rtc_entries) { 233 if (rtc->resolution > newrtc->resolution) { 234 LIST_INSERT_BEFORE(rtc, newrtc, rtc_entries); 235 break; 236 } else if (LIST_NEXT(rtc, rtc_entries) == NULL) { 237 LIST_INSERT_AFTER(rtc, newrtc, rtc_entries); 238 break; 239 } 240 } 241 } 242 sx_xunlock(&rtc_list_lock); 243 244 device_printf(clockdev, 245 "registered as a time-of-day clock, resolution %d.%6.6ds\n", 246 newrtc->resolution / 1000000, newrtc->resolution % 1000000); 247 } 248 249 void 250 clock_register(device_t dev, long res) 251 { 252 253 clock_register_flags(dev, res, 0); 254 } 255 256 void 257 clock_unregister(device_t clockdev) 258 { 259 struct rtc_instance *rtc, *tmp; 260 261 sx_xlock(&rtc_list_lock); 262 LIST_FOREACH_SAFE(rtc, &rtc_list, rtc_entries, tmp) { 263 if (rtc->clockdev == clockdev) { 264 LIST_REMOVE(rtc, rtc_entries); 265 break; 266 } 267 } 268 sx_xunlock(&rtc_list_lock); 269 if (rtc != NULL) { 270 taskqueue_cancel_timeout(taskqueue_thread, &rtc->stask, NULL); 271 taskqueue_drain_timeout(taskqueue_thread, &rtc->stask); 272 free(rtc, M_DEVBUF); 273 } 274 } 275 276 void 277 clock_schedule(device_t clockdev, u_int offsetns) 278 { 279 struct rtc_instance *rtc; 280 281 sx_xlock(&rtc_list_lock); 282 LIST_FOREACH(rtc, &rtc_list, rtc_entries) { 283 if (rtc->clockdev == clockdev) { 284 rtc->schedns = offsetns; 285 break; 286 } 287 } 288 sx_xunlock(&rtc_list_lock); 289 } 290 291 static int 292 read_clocks(struct timespec *ts, bool debug_read) 293 { 294 struct rtc_instance *rtc; 295 int error; 296 297 error = ENXIO; 298 sx_xlock(&rtc_list_lock); 299 LIST_FOREACH(rtc, &rtc_list, rtc_entries) { 300 if ((error = CLOCK_GETTIME(rtc->clockdev, ts)) != 0) 301 continue; 302 if (ts->tv_sec < 0 || ts->tv_nsec < 0) { 303 error = EINVAL; 304 continue; 305 } 306 if (!(rtc->flags & CLOCKF_GETTIME_NO_ADJ)) { 307 timespecadd(ts, &rtc->resadj, ts); 308 ts->tv_sec += utc_offset(); 309 } 310 if (!debug_read) { 311 if (bootverbose) 312 device_printf(rtc->clockdev, 313 "providing initial system time\n"); 314 break; 315 } 316 } 317 sx_xunlock(&rtc_list_lock); 318 return (error); 319 } 320 321 /* 322 * Initialize the system time. Must be called from a context which does not 323 * restrict any locking or sleeping that clock drivers may need to do. 324 * 325 * First attempt to get the time from a registered realtime clock. The clocks 326 * are queried in order of resolution until one provides the time. If no clock 327 * can provide the current time, use the 'base' time provided by the caller, if 328 * non-zero. The 'base' time is potentially highly inaccurate, such as the last 329 * known good value of the system clock, or even a filesystem last-updated 330 * timestamp. It is used to prevent system time from appearing to move 331 * backwards in logs. 332 */ 333 void 334 inittodr(time_t base) 335 { 336 struct timespec ts; 337 int error; 338 339 error = read_clocks(&ts, false); 340 341 /* 342 * Do not report errors from each clock; it is expected that some clocks 343 * cannot provide results in some situations. Only report problems when 344 * no clocks could provide the time. 345 */ 346 if (error != 0) { 347 switch (error) { 348 case ENXIO: 349 printf("Warning: no time-of-day clock registered, "); 350 break; 351 case EINVAL: 352 printf("Warning: bad time from time-of-day clock, "); 353 break; 354 default: 355 printf("Error reading time-of-day clock (%d), ", error); 356 break; 357 } 358 printf("system time will not be set accurately\n"); 359 ts.tv_sec = (base > 0) ? base : -1; 360 ts.tv_nsec = 0; 361 } 362 363 if (ts.tv_sec >= 0) { 364 tc_setclock(&ts); 365 #ifdef FFCLOCK 366 ffclock_reset_clock(&ts); 367 #endif 368 } 369 } 370 371 /* 372 * Write system time back to all registered clocks, unless disabled by admin. 373 * This can be called from a context that restricts locking and/or sleeping; the 374 * actual updating is done asynchronously on a task thread. 375 */ 376 void 377 resettodr(void) 378 { 379 struct timespec now; 380 struct rtc_instance *rtc; 381 sbintime_t sbt; 382 long waitns; 383 384 if (disable_rtc_set) 385 return; 386 387 sx_xlock(&rtc_list_lock); 388 LIST_FOREACH(rtc, &rtc_list, rtc_entries) { 389 if (rtc->schedns != 0) { 390 getnanotime(&now); 391 waitns = rtc->schedns - now.tv_nsec; 392 if (waitns < 0) 393 waitns += 1000000000; 394 sbt = nstosbt(waitns); 395 } else 396 sbt = 0; 397 taskqueue_enqueue_timeout_sbt(taskqueue_thread, 398 &rtc->stask, -sbt, 0, C_PREL(31)); 399 } 400 sx_xunlock(&rtc_list_lock); 401 } 402 403 static int 404 sysctl_clock_do_io(SYSCTL_HANDLER_ARGS) 405 { 406 struct timespec ts_discard; 407 int error, value; 408 409 value = 0; 410 error = sysctl_handle_int(oidp, &value, 0, req); 411 if (error != 0 || req->newptr == NULL) 412 return (error); 413 414 switch (value) { 415 case CLOCK_DBG_READ: 416 if (read_clocks(&ts_discard, true) == ENXIO) 417 printf("No registered RTC clocks\n"); 418 break; 419 case CLOCK_DBG_WRITE: 420 resettodr(); 421 break; 422 default: 423 return (EINVAL); 424 } 425 426 return (0); 427 } 428