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