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