2 * Copyright (c) 1988 University of Utah.
3 * Copyright (c) 1982, 1990, 1993
4 * The Regents of the University of California.
5 * Copyright (c) 2011 The FreeBSD Foundation
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
12 * Portions of this software were developed by Julien Ridoux at the University
13 * of Melbourne under sponsorship from the FreeBSD Foundation.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 * from: Utah $Hdr: clock.c 1.18 91/01/21$
40 * from: @(#)clock.c 8.2 (Berkeley) 1/12/94
41 * from: NetBSD: clock_subr.c,v 1.6 2001/07/07 17:04:02 thorpej Exp
43 * from: src/sys/i386/isa/clock.c,v 1.176 2001/09/04
47 * Helpers for time-of-day clocks. This is useful for architectures that need
48 * support multiple models of such clocks, and generally serves to make the
49 * code more machine-independent.
50 * If the clock in question can also be used as a time counter, the driver
51 * needs to initiate this.
52 * This code is not yet used by all architectures.
55 #include <sys/cdefs.h>
56 __FBSDID("$FreeBSD$");
58 #include "opt_ffclock.h"
60 #include <sys/param.h>
61 #include <sys/systm.h>
62 #include <sys/kernel.h>
64 #include <sys/clock.h>
66 #include <sys/malloc.h>
68 #include <sys/sysctl.h>
69 #include <sys/taskqueue.h>
71 #include <sys/timeffc.h>
73 #include <sys/timetc.h>
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.");
81 static int sysctl_clock_do_io(SYSCTL_HANDLER_ARGS);
82 SYSCTL_PROC(_debug, OID_AUTO, clock_do_io, CTLTYPE_INT | CTLFLAG_RW,
83 0, 0, sysctl_clock_do_io, "I",
84 "Trigger one-time IO on RTC clocks; 1=read (and discard), 2=write");
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");
92 * An instance of a realtime clock. A list of these tracks all the registered
93 * clocks in the system.
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.
103 struct rtc_instance {
108 struct timespec resadj;
111 LIST_ENTRY(rtc_instance)
116 * Clocks are updated using a task running on taskqueue_thread.
118 static void settime_task_func(void *arg, int pending);
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.
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");
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.
135 settime_task_func(void *arg, int pending)
138 struct rtc_instance *rtc;
142 if (!(rtc->flags & CLOCKF_SETTIME_NO_TS)) {
144 if (!(rtc->flags & CLOCKF_SETTIME_NO_ADJ)) {
145 ts.tv_sec -= utc_offset();
146 timespecadd(&ts, &rtc->resadj);
152 error = CLOCK_SETTIME(rtc->clockdev, &ts);
153 if (error != 0 && bootverbose)
154 device_printf(rtc->clockdev, "CLOCK_SETTIME error %d\n", error);
158 clock_dbgprint_hdr(device_t dev, int rw)
163 device_printf(dev, "%s at ", (rw & CLOCK_DBG_READ) ? "read " : "write");
164 clock_print_ts(&now, 9);
169 clock_dbgprint_bcd(device_t dev, int rw, const struct bcd_clocktime *bct)
173 clock_dbgprint_hdr(dev, rw);
174 clock_print_bcd(bct, 9);
180 clock_dbgprint_ct(device_t dev, int rw, const struct clocktime *ct)
184 clock_dbgprint_hdr(dev, rw);
185 clock_print_ct(ct, 9);
191 clock_dbgprint_err(device_t dev, int rw, int err)
195 clock_dbgprint_hdr(dev, rw);
196 printf("error = %d\n", err);
201 clock_dbgprint_ts(device_t dev, int rw, const struct timespec *ts)
205 clock_dbgprint_hdr(dev, rw);
206 clock_print_ts(ts, 9);
212 clock_register_flags(device_t clockdev, long resolution, int flags)
214 struct rtc_instance *rtc, *newrtc;
216 newrtc = malloc(sizeof(*newrtc), M_DEVBUF, M_WAITOK);
217 newrtc->clockdev = clockdev;
218 newrtc->resolution = (int)resolution;
219 newrtc->flags = flags;
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);
226 sx_xlock(&rtc_list_lock);
227 if (LIST_EMPTY(&rtc_list)) {
228 LIST_INSERT_HEAD(&rtc_list, newrtc, rtc_entries);
230 LIST_FOREACH(rtc, &rtc_list, rtc_entries) {
231 if (rtc->resolution > newrtc->resolution) {
232 LIST_INSERT_BEFORE(rtc, newrtc, rtc_entries);
234 } else if (LIST_NEXT(rtc, rtc_entries) == NULL) {
235 LIST_INSERT_AFTER(rtc, newrtc, rtc_entries);
240 sx_xunlock(&rtc_list_lock);
242 device_printf(clockdev,
243 "registered as a time-of-day clock, resolution %d.%6.6ds\n",
244 newrtc->resolution / 1000000, newrtc->resolution % 1000000);
248 clock_register(device_t dev, long res)
251 clock_register_flags(dev, res, 0);
255 clock_unregister(device_t clockdev)
257 struct rtc_instance *rtc, *tmp;
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);
266 sx_xunlock(&rtc_list_lock);
268 taskqueue_cancel_timeout(taskqueue_thread, &rtc->stask, NULL);
269 taskqueue_drain_timeout(taskqueue_thread, &rtc->stask);
275 clock_schedule(device_t clockdev, u_int offsetns)
277 struct rtc_instance *rtc;
279 sx_xlock(&rtc_list_lock);
280 LIST_FOREACH(rtc, &rtc_list, rtc_entries) {
281 if (rtc->clockdev == clockdev) {
282 rtc->schedns = offsetns;
286 sx_xunlock(&rtc_list_lock);
290 read_clocks(struct timespec *ts, bool debug_read)
292 struct rtc_instance *rtc;
296 sx_xlock(&rtc_list_lock);
297 LIST_FOREACH(rtc, &rtc_list, rtc_entries) {
298 if ((error = CLOCK_GETTIME(rtc->clockdev, ts)) != 0)
300 if (ts->tv_sec < 0 || ts->tv_nsec < 0) {
304 if (!(rtc->flags & CLOCKF_GETTIME_NO_ADJ)) {
305 timespecadd(ts, &rtc->resadj);
306 ts->tv_sec += utc_offset();
310 device_printf(rtc->clockdev,
311 "providing initial system time\n");
315 sx_xunlock(&rtc_list_lock);
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.
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
332 inittodr(time_t base)
337 error = read_clocks(&ts, false);
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.
347 printf("Warning: no time-of-day clock registered, ");
350 printf("Warning: bad time from time-of-day clock, ");
353 printf("Error reading time-of-day clock (%d), ", error);
356 printf("system time will not be set accurately\n");
357 ts.tv_sec = (base > 0) ? base : -1;
361 if (ts.tv_sec >= 0) {
364 ffclock_reset_clock(&ts);
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.
378 struct rtc_instance *rtc;
385 sx_xlock(&rtc_list_lock);
386 LIST_FOREACH(rtc, &rtc_list, rtc_entries) {
387 if (rtc->schedns != 0) {
389 waitns = rtc->schedns - now.tv_nsec;
391 waitns += 1000000000;
392 sbt = nstosbt(waitns);
395 taskqueue_enqueue_timeout_sbt(taskqueue_thread,
396 &rtc->stask, -sbt, 0, C_PREL(31));
398 sx_xunlock(&rtc_list_lock);
402 sysctl_clock_do_io(SYSCTL_HANDLER_ARGS)
404 struct timespec ts_discard;
408 error = sysctl_handle_int(oidp, &value, 0, req);
409 if (error != 0 || req->newptr == NULL)
414 if (read_clocks(&ts_discard, true) == ENXIO)
415 printf("No registered RTC clocks\n");
417 case CLOCK_DBG_WRITE: