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 #include "opt_ffclock.h" 59 60 #include <sys/param.h> 61 #include <sys/systm.h> 62 #include <sys/kernel.h> 63 #include <sys/bus.h> 64 #include <sys/clock.h> 65 #include <sys/lock.h> 66 #include <sys/malloc.h> 67 #include <sys/sx.h> 68 #include <sys/sysctl.h> 69 #include <sys/taskqueue.h> 70 #ifdef FFCLOCK 71 #include <sys/timeffc.h> 72 #endif 73 #include <sys/timetc.h> 74 75 #include "clock_if.h" 76 77 static int show_io; 78 SYSCTL_INT(_debug, OID_AUTO, clock_show_io, CTLFLAG_RWTUN, &show_io, 0, 79 "Enable debug printing of RTC clock I/O; 1=reads, 2=writes, 3=both."); 80 81 static int sysctl_clock_do_io(SYSCTL_HANDLER_ARGS); 82 SYSCTL_PROC(_debug, OID_AUTO, clock_do_io, 83 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0, sysctl_clock_do_io, "I", 84 "Trigger one-time IO on RTC clocks; 1=read (and discard), 2=write"); 85 86 /* XXX: should be kern. now, it's no longer machdep. */ 87 static int disable_rtc_set; 88 SYSCTL_INT(_machdep, OID_AUTO, disable_rtc_set, CTLFLAG_RW, &disable_rtc_set, 89 0, "Disallow adjusting time-of-day clock"); 90 91 /* 92 * An instance of a realtime clock. A list of these tracks all the registered 93 * clocks in the system. 94 * 95 * The resadj member is used to apply a "resolution adjustment" equal to half 96 * the clock's resolution, which is useful mainly on clocks with a whole-second 97 * resolution. Because the clock truncates the fractional part, adding half the 98 * resolution performs 4/5 rounding. The same adjustment is applied to the 99 * times returned from clock_gettime(), because the fraction returned will 100 * always be zero, but on average the actual fraction at the time of the call 101 * should be about .5. 102 */ 103 struct rtc_instance { 104 device_t clockdev; 105 int resolution; 106 int flags; 107 u_int schedns; 108 struct timespec resadj; 109 struct timeout_task 110 stask; 111 LIST_ENTRY(rtc_instance) 112 rtc_entries; 113 }; 114 115 /* 116 * Clocks are updated using a task running on taskqueue_thread. 117 */ 118 static void settime_task_func(void *arg, int pending); 119 120 /* 121 * Registered clocks are kept in a list which is sorted by resolution; the more 122 * accurate clocks get the first shot at providing the time. 123 */ 124 LIST_HEAD(rtc_listhead, rtc_instance); 125 static struct rtc_listhead rtc_list = LIST_HEAD_INITIALIZER(rtc_list); 126 static struct sx rtc_list_lock; 127 SX_SYSINIT(rtc_list_lock_init, &rtc_list_lock, "rtc list"); 128 129 /* 130 * On the task thread, invoke the clock_settime() method of the clock. Do so 131 * holding no locks, so that clock drivers are free to do whatever kind of 132 * locking or sleeping they need to. 133 */ 134 static void 135 settime_task_func(void *arg, int pending) 136 { 137 struct timespec ts; 138 struct rtc_instance *rtc; 139 int error; 140 141 rtc = arg; 142 if (!(rtc->flags & CLOCKF_SETTIME_NO_TS)) { 143 getnanotime(&ts); 144 if (!(rtc->flags & CLOCKF_SETTIME_NO_ADJ)) { 145 ts.tv_sec -= utc_offset(); 146 timespecadd(&ts, &rtc->resadj, &ts); 147 } 148 } else { 149 ts.tv_sec = 0; 150 ts.tv_nsec = 0; 151 } 152 error = CLOCK_SETTIME(rtc->clockdev, &ts); 153 if (error != 0 && bootverbose) 154 device_printf(rtc->clockdev, "CLOCK_SETTIME error %d\n", error); 155 } 156 157 static void 158 clock_dbgprint_hdr(device_t dev, int rw) 159 { 160 struct timespec now; 161 162 getnanotime(&now); 163 device_printf(dev, "%s at ", (rw & CLOCK_DBG_READ) ? "read " : "write"); 164 clock_print_ts(&now, 9); 165 printf(": "); 166 } 167 168 void 169 clock_dbgprint_bcd(device_t dev, int rw, const struct bcd_clocktime *bct) 170 { 171 172 if (show_io & rw) { 173 clock_dbgprint_hdr(dev, rw); 174 clock_print_bcd(bct, 9); 175 printf("\n"); 176 } 177 } 178 179 void 180 clock_dbgprint_ct(device_t dev, int rw, const struct clocktime *ct) 181 { 182 183 if (show_io & rw) { 184 clock_dbgprint_hdr(dev, rw); 185 clock_print_ct(ct, 9); 186 printf("\n"); 187 } 188 } 189 190 void 191 clock_dbgprint_err(device_t dev, int rw, int err) 192 { 193 194 if (show_io & rw) { 195 clock_dbgprint_hdr(dev, rw); 196 printf("error = %d\n", err); 197 } 198 } 199 200 void 201 clock_dbgprint_ts(device_t dev, int rw, const struct timespec *ts) 202 { 203 204 if (show_io & rw) { 205 clock_dbgprint_hdr(dev, rw); 206 clock_print_ts(ts, 9); 207 printf("\n"); 208 } 209 } 210 211 void 212 clock_register_flags(device_t clockdev, long resolution, int flags) 213 { 214 struct rtc_instance *rtc, *newrtc; 215 216 newrtc = malloc(sizeof(*newrtc), M_DEVBUF, M_WAITOK); 217 newrtc->clockdev = clockdev; 218 newrtc->resolution = (int)resolution; 219 newrtc->flags = flags; 220 newrtc->schedns = 0; 221 newrtc->resadj.tv_sec = newrtc->resolution / 2 / 1000000; 222 newrtc->resadj.tv_nsec = newrtc->resolution / 2 % 1000000 * 1000; 223 TIMEOUT_TASK_INIT(taskqueue_thread, &newrtc->stask, 0, 224 settime_task_func, newrtc); 225 226 sx_xlock(&rtc_list_lock); 227 if (LIST_EMPTY(&rtc_list)) { 228 LIST_INSERT_HEAD(&rtc_list, newrtc, rtc_entries); 229 } else { 230 LIST_FOREACH(rtc, &rtc_list, rtc_entries) { 231 if (rtc->resolution > newrtc->resolution) { 232 LIST_INSERT_BEFORE(rtc, newrtc, rtc_entries); 233 break; 234 } else if (LIST_NEXT(rtc, rtc_entries) == NULL) { 235 LIST_INSERT_AFTER(rtc, newrtc, rtc_entries); 236 break; 237 } 238 } 239 } 240 sx_xunlock(&rtc_list_lock); 241 242 device_printf(clockdev, 243 "registered as a time-of-day clock, resolution %d.%6.6ds\n", 244 newrtc->resolution / 1000000, newrtc->resolution % 1000000); 245 } 246 247 void 248 clock_register(device_t dev, long res) 249 { 250 251 clock_register_flags(dev, res, 0); 252 } 253 254 void 255 clock_unregister(device_t clockdev) 256 { 257 struct rtc_instance *rtc, *tmp; 258 259 sx_xlock(&rtc_list_lock); 260 LIST_FOREACH_SAFE(rtc, &rtc_list, rtc_entries, tmp) { 261 if (rtc->clockdev == clockdev) { 262 LIST_REMOVE(rtc, rtc_entries); 263 break; 264 } 265 } 266 sx_xunlock(&rtc_list_lock); 267 if (rtc != NULL) { 268 taskqueue_cancel_timeout(taskqueue_thread, &rtc->stask, NULL); 269 taskqueue_drain_timeout(taskqueue_thread, &rtc->stask); 270 free(rtc, M_DEVBUF); 271 } 272 } 273 274 void 275 clock_schedule(device_t clockdev, u_int offsetns) 276 { 277 struct rtc_instance *rtc; 278 279 sx_xlock(&rtc_list_lock); 280 LIST_FOREACH(rtc, &rtc_list, rtc_entries) { 281 if (rtc->clockdev == clockdev) { 282 rtc->schedns = offsetns; 283 break; 284 } 285 } 286 sx_xunlock(&rtc_list_lock); 287 } 288 289 static int 290 read_clocks(struct timespec *ts, bool debug_read) 291 { 292 struct rtc_instance *rtc; 293 int error; 294 295 error = ENXIO; 296 sx_xlock(&rtc_list_lock); 297 LIST_FOREACH(rtc, &rtc_list, rtc_entries) { 298 if ((error = CLOCK_GETTIME(rtc->clockdev, ts)) != 0) 299 continue; 300 if (ts->tv_sec < 0 || ts->tv_nsec < 0) { 301 error = EINVAL; 302 continue; 303 } 304 if (!(rtc->flags & CLOCKF_GETTIME_NO_ADJ)) { 305 timespecadd(ts, &rtc->resadj, ts); 306 ts->tv_sec += utc_offset(); 307 } 308 if (!debug_read) { 309 if (bootverbose) 310 device_printf(rtc->clockdev, 311 "providing initial system time\n"); 312 break; 313 } 314 } 315 sx_xunlock(&rtc_list_lock); 316 return (error); 317 } 318 319 /* 320 * Initialize the system time. Must be called from a context which does not 321 * restrict any locking or sleeping that clock drivers may need to do. 322 * 323 * First attempt to get the time from a registered realtime clock. The clocks 324 * are queried in order of resolution until one provides the time. If no clock 325 * can provide the current time, use the 'base' time provided by the caller, if 326 * non-zero. The 'base' time is potentially highly inaccurate, such as the last 327 * known good value of the system clock, or even a filesystem last-updated 328 * timestamp. It is used to prevent system time from appearing to move 329 * backwards in logs. 330 */ 331 void 332 inittodr(time_t base) 333 { 334 struct timespec ts; 335 int error; 336 337 error = read_clocks(&ts, false); 338 339 /* 340 * Do not report errors from each clock; it is expected that some clocks 341 * cannot provide results in some situations. Only report problems when 342 * no clocks could provide the time. 343 */ 344 if (error != 0) { 345 switch (error) { 346 case ENXIO: 347 printf("Warning: no time-of-day clock registered, "); 348 break; 349 case EINVAL: 350 printf("Warning: bad time from time-of-day clock, "); 351 break; 352 default: 353 printf("Error reading time-of-day clock (%d), ", error); 354 break; 355 } 356 printf("system time will not be set accurately\n"); 357 ts.tv_sec = (base > 0) ? base : -1; 358 ts.tv_nsec = 0; 359 } 360 361 if (ts.tv_sec >= 0) { 362 tc_setclock(&ts); 363 #ifdef FFCLOCK 364 ffclock_reset_clock(&ts); 365 #endif 366 } 367 } 368 369 /* 370 * Write system time back to all registered clocks, unless disabled by admin. 371 * This can be called from a context that restricts locking and/or sleeping; the 372 * actual updating is done asynchronously on a task thread. 373 */ 374 void 375 resettodr(void) 376 { 377 struct timespec now; 378 struct rtc_instance *rtc; 379 sbintime_t sbt; 380 long waitns; 381 382 if (disable_rtc_set) 383 return; 384 385 sx_xlock(&rtc_list_lock); 386 LIST_FOREACH(rtc, &rtc_list, rtc_entries) { 387 if (rtc->schedns != 0) { 388 getnanotime(&now); 389 waitns = rtc->schedns - now.tv_nsec; 390 if (waitns < 0) 391 waitns += 1000000000; 392 sbt = nstosbt(waitns); 393 } else 394 sbt = 0; 395 taskqueue_enqueue_timeout_sbt(taskqueue_thread, 396 &rtc->stask, -sbt, 0, C_PREL(31)); 397 } 398 sx_xunlock(&rtc_list_lock); 399 } 400 401 static int 402 sysctl_clock_do_io(SYSCTL_HANDLER_ARGS) 403 { 404 struct timespec ts_discard; 405 int error, value; 406 407 value = 0; 408 error = sysctl_handle_int(oidp, &value, 0, req); 409 if (error != 0 || req->newptr == NULL) 410 return (error); 411 412 switch (value) { 413 case CLOCK_DBG_READ: 414 if (read_clocks(&ts_discard, true) == ENXIO) 415 printf("No registered RTC clocks\n"); 416 break; 417 case CLOCK_DBG_WRITE: 418 resettodr(); 419 break; 420 default: 421 return (EINVAL); 422 } 423 424 return (0); 425 } 426