/*-
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ffclock.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/taskqueue.h>
#ifdef FFCLOCK
#include <sys/timeffc.h>
#endif
#include <sys/timetc.h>
#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);
}
