/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1988 University of Utah. * Copyright (c) 1982, 1990, 1993 * The Regents of the University of California. * Copyright (c) 2011 The FreeBSD Foundation * All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department. * * Portions of this software were developed by Julien Ridoux at the University * of Melbourne under sponsorship from the FreeBSD Foundation. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: Utah $Hdr: clock.c 1.18 91/01/21$ * from: @(#)clock.c 8.2 (Berkeley) 1/12/94 * from: NetBSD: clock_subr.c,v 1.6 2001/07/07 17:04:02 thorpej Exp * and * from: src/sys/i386/isa/clock.c,v 1.176 2001/09/04 */ /* * Helpers for time-of-day clocks. This is useful for architectures that need * support multiple models of such clocks, and generally serves to make the * code more machine-independent. * If the clock in question can also be used as a time counter, the driver * needs to initiate this. * This code is not yet used by all architectures. */ #include __FBSDID("$FreeBSD$"); #include "opt_ffclock.h" #include #include #include #include #include #include #include #include #include #include #ifdef FFCLOCK #include #endif #include #include "clock_if.h" static int show_io; SYSCTL_INT(_debug, OID_AUTO, clock_show_io, CTLFLAG_RWTUN, &show_io, 0, "Enable debug printing of RTC clock I/O; 1=reads, 2=writes, 3=both."); static int sysctl_clock_do_io(SYSCTL_HANDLER_ARGS); SYSCTL_PROC(_debug, OID_AUTO, clock_do_io, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0, sysctl_clock_do_io, "I", "Trigger one-time IO on RTC clocks; 1=read (and discard), 2=write"); /* XXX: should be kern. now, it's no longer machdep. */ static int disable_rtc_set; SYSCTL_INT(_machdep, OID_AUTO, disable_rtc_set, CTLFLAG_RW, &disable_rtc_set, 0, "Disallow adjusting time-of-day clock"); /* * An instance of a realtime clock. A list of these tracks all the registered * clocks in the system. * * The resadj member is used to apply a "resolution adjustment" equal to half * the clock's resolution, which is useful mainly on clocks with a whole-second * resolution. Because the clock truncates the fractional part, adding half the * resolution performs 4/5 rounding. The same adjustment is applied to the * times returned from clock_gettime(), because the fraction returned will * always be zero, but on average the actual fraction at the time of the call * should be about .5. */ struct rtc_instance { device_t clockdev; int resolution; int flags; u_int schedns; struct timespec resadj; struct timeout_task stask; LIST_ENTRY(rtc_instance) rtc_entries; }; /* * Clocks are updated using a task running on taskqueue_thread. */ static void settime_task_func(void *arg, int pending); /* * Registered clocks are kept in a list which is sorted by resolution; the more * accurate clocks get the first shot at providing the time. */ LIST_HEAD(rtc_listhead, rtc_instance); static struct rtc_listhead rtc_list = LIST_HEAD_INITIALIZER(rtc_list); static struct sx rtc_list_lock; SX_SYSINIT(rtc_list_lock_init, &rtc_list_lock, "rtc list"); /* * On the task thread, invoke the clock_settime() method of the clock. Do so * holding no locks, so that clock drivers are free to do whatever kind of * locking or sleeping they need to. */ static void settime_task_func(void *arg, int pending) { struct timespec ts; struct rtc_instance *rtc; int error; rtc = arg; if (!(rtc->flags & CLOCKF_SETTIME_NO_TS)) { getnanotime(&ts); if (!(rtc->flags & CLOCKF_SETTIME_NO_ADJ)) { ts.tv_sec -= utc_offset(); timespecadd(&ts, &rtc->resadj, &ts); } } else { ts.tv_sec = 0; ts.tv_nsec = 0; } error = CLOCK_SETTIME(rtc->clockdev, &ts); if (error != 0 && bootverbose) device_printf(rtc->clockdev, "CLOCK_SETTIME error %d\n", error); } static void clock_dbgprint_hdr(device_t dev, int rw) { struct timespec now; getnanotime(&now); device_printf(dev, "%s at ", (rw & CLOCK_DBG_READ) ? "read " : "write"); clock_print_ts(&now, 9); printf(": "); } void clock_dbgprint_bcd(device_t dev, int rw, const struct bcd_clocktime *bct) { if (show_io & rw) { clock_dbgprint_hdr(dev, rw); clock_print_bcd(bct, 9); printf("\n"); } } void clock_dbgprint_ct(device_t dev, int rw, const struct clocktime *ct) { if (show_io & rw) { clock_dbgprint_hdr(dev, rw); clock_print_ct(ct, 9); printf("\n"); } } void clock_dbgprint_err(device_t dev, int rw, int err) { if (show_io & rw) { clock_dbgprint_hdr(dev, rw); printf("error = %d\n", err); } } void clock_dbgprint_ts(device_t dev, int rw, const struct timespec *ts) { if (show_io & rw) { clock_dbgprint_hdr(dev, rw); clock_print_ts(ts, 9); printf("\n"); } } void clock_register_flags(device_t clockdev, long resolution, int flags) { struct rtc_instance *rtc, *newrtc; newrtc = malloc(sizeof(*newrtc), M_DEVBUF, M_WAITOK); newrtc->clockdev = clockdev; newrtc->resolution = (int)resolution; newrtc->flags = flags; newrtc->schedns = 0; newrtc->resadj.tv_sec = newrtc->resolution / 2 / 1000000; newrtc->resadj.tv_nsec = newrtc->resolution / 2 % 1000000 * 1000; TIMEOUT_TASK_INIT(taskqueue_thread, &newrtc->stask, 0, settime_task_func, newrtc); sx_xlock(&rtc_list_lock); if (LIST_EMPTY(&rtc_list)) { LIST_INSERT_HEAD(&rtc_list, newrtc, rtc_entries); } else { LIST_FOREACH(rtc, &rtc_list, rtc_entries) { if (rtc->resolution > newrtc->resolution) { LIST_INSERT_BEFORE(rtc, newrtc, rtc_entries); break; } else if (LIST_NEXT(rtc, rtc_entries) == NULL) { LIST_INSERT_AFTER(rtc, newrtc, rtc_entries); break; } } } sx_xunlock(&rtc_list_lock); device_printf(clockdev, "registered as a time-of-day clock, resolution %d.%6.6ds\n", newrtc->resolution / 1000000, newrtc->resolution % 1000000); } void clock_register(device_t dev, long res) { clock_register_flags(dev, res, 0); } void clock_unregister(device_t clockdev) { struct rtc_instance *rtc, *tmp; sx_xlock(&rtc_list_lock); LIST_FOREACH_SAFE(rtc, &rtc_list, rtc_entries, tmp) { if (rtc->clockdev == clockdev) { LIST_REMOVE(rtc, rtc_entries); break; } } sx_xunlock(&rtc_list_lock); if (rtc != NULL) { taskqueue_cancel_timeout(taskqueue_thread, &rtc->stask, NULL); taskqueue_drain_timeout(taskqueue_thread, &rtc->stask); free(rtc, M_DEVBUF); } } void clock_schedule(device_t clockdev, u_int offsetns) { struct rtc_instance *rtc; sx_xlock(&rtc_list_lock); LIST_FOREACH(rtc, &rtc_list, rtc_entries) { if (rtc->clockdev == clockdev) { rtc->schedns = offsetns; break; } } sx_xunlock(&rtc_list_lock); } static int read_clocks(struct timespec *ts, bool debug_read) { struct rtc_instance *rtc; int error; error = ENXIO; sx_xlock(&rtc_list_lock); LIST_FOREACH(rtc, &rtc_list, rtc_entries) { if ((error = CLOCK_GETTIME(rtc->clockdev, ts)) != 0) continue; if (ts->tv_sec < 0 || ts->tv_nsec < 0) { error = EINVAL; continue; } if (!(rtc->flags & CLOCKF_GETTIME_NO_ADJ)) { timespecadd(ts, &rtc->resadj, ts); ts->tv_sec += utc_offset(); } if (!debug_read) { if (bootverbose) device_printf(rtc->clockdev, "providing initial system time\n"); break; } } sx_xunlock(&rtc_list_lock); return (error); } /* * Initialize the system time. Must be called from a context which does not * restrict any locking or sleeping that clock drivers may need to do. * * First attempt to get the time from a registered realtime clock. The clocks * are queried in order of resolution until one provides the time. If no clock * can provide the current time, use the 'base' time provided by the caller, if * non-zero. The 'base' time is potentially highly inaccurate, such as the last * known good value of the system clock, or even a filesystem last-updated * timestamp. It is used to prevent system time from appearing to move * backwards in logs. */ void inittodr(time_t base) { struct timespec ts; int error; error = read_clocks(&ts, false); /* * Do not report errors from each clock; it is expected that some clocks * cannot provide results in some situations. Only report problems when * no clocks could provide the time. */ if (error != 0) { switch (error) { case ENXIO: printf("Warning: no time-of-day clock registered, "); break; case EINVAL: printf("Warning: bad time from time-of-day clock, "); break; default: printf("Error reading time-of-day clock (%d), ", error); break; } printf("system time will not be set accurately\n"); ts.tv_sec = (base > 0) ? base : -1; ts.tv_nsec = 0; } if (ts.tv_sec >= 0) { tc_setclock(&ts); #ifdef FFCLOCK ffclock_reset_clock(&ts); #endif } } /* * Write system time back to all registered clocks, unless disabled by admin. * This can be called from a context that restricts locking and/or sleeping; the * actual updating is done asynchronously on a task thread. */ void resettodr(void) { struct timespec now; struct rtc_instance *rtc; sbintime_t sbt; long waitns; if (disable_rtc_set) return; sx_xlock(&rtc_list_lock); LIST_FOREACH(rtc, &rtc_list, rtc_entries) { if (rtc->schedns != 0) { getnanotime(&now); waitns = rtc->schedns - now.tv_nsec; if (waitns < 0) waitns += 1000000000; sbt = nstosbt(waitns); } else sbt = 0; taskqueue_enqueue_timeout_sbt(taskqueue_thread, &rtc->stask, -sbt, 0, C_PREL(31)); } sx_xunlock(&rtc_list_lock); } static int sysctl_clock_do_io(SYSCTL_HANDLER_ARGS) { struct timespec ts_discard; int error, value; value = 0; error = sysctl_handle_int(oidp, &value, 0, req); if (error != 0 || req->newptr == NULL) return (error); switch (value) { case CLOCK_DBG_READ: if (read_clocks(&ts_discard, true) == ENXIO) printf("No registered RTC clocks\n"); break; case CLOCK_DBG_WRITE: resettodr(); break; default: return (EINVAL); } return (0); }