freebsd-dev/sys/kern/subr_rtc.c
Konstantin Belousov 3a0e6f920a Do not use Giant to prevent parallel calls to CLOCK_SETTIME(). Use
private mtx in resettodr(), no implementation of CLOCK_SETTIME() is
allowed to sleep.

Reviewed by:	  imp, jhb
Sponsored by:	  The FreeBSD Foundation
Approved by:	  re (gjb)
X-Differential revision:	https://reviews.freebsd.org/D6825
2016-06-28 16:42:40 +00:00

186 lines
5.7 KiB
C

/*-
* 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.
* 4. 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/mutex.h>
#include <sys/sysctl.h>
#ifdef FFCLOCK
#include <sys/timeffc.h>
#endif
#include <sys/timetc.h>
#include "clock_if.h"
static device_t clock_dev = NULL;
static long clock_res;
static struct timespec clock_adj;
static struct mtx resettodr_lock;
MTX_SYSINIT(resettodr_init, &resettodr_lock, "tod2rl", MTX_DEF);
/* 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");
void
clock_register(device_t dev, long res) /* res has units of microseconds */
{
if (clock_dev != NULL) {
if (clock_res <= res) {
if (bootverbose)
device_printf(dev, "not installed as "
"time-of-day clock: clock %s has higher "
"resolution\n", device_get_name(clock_dev));
return;
}
if (bootverbose)
device_printf(clock_dev, "removed as "
"time-of-day clock: clock %s has higher "
"resolution\n", device_get_name(dev));
}
clock_dev = dev;
clock_res = res;
clock_adj.tv_sec = res / 2 / 1000000;
clock_adj.tv_nsec = res / 2 % 1000000 * 1000;
if (bootverbose)
device_printf(dev, "registered as a time-of-day clock "
"(resolution %ldus, adjustment %jd.%09jds)\n", res,
(intmax_t)clock_adj.tv_sec, (intmax_t)clock_adj.tv_nsec);
}
/*
* inittodr and settodr derived from the i386 versions written
* by Christoph Robitschko <chmr@edvz.tu-graz.ac.at>, reintroduced and
* updated by Chris Stenton <chris@gnome.co.uk> 8/10/94
*/
/*
* Initialize the time of day register, based on the time base which is, e.g.
* from a filesystem.
*/
void
inittodr(time_t base)
{
struct timespec ts;
int error;
if (clock_dev == NULL) {
printf("warning: no time-of-day clock registered, system time "
"will not be set accurately\n");
goto wrong_time;
}
/* XXX: We should poll all registered RTCs in case of failure */
error = CLOCK_GETTIME(clock_dev, &ts);
if (error != 0 && error != EINVAL) {
printf("warning: clock_gettime failed (%d), the system time "
"will not be set accurately\n", error);
goto wrong_time;
}
if (error == EINVAL || ts.tv_sec < 0) {
printf("Invalid time in real time clock.\n"
"Check and reset the date immediately!\n");
goto wrong_time;
}
ts.tv_sec += utc_offset();
timespecadd(&ts, &clock_adj);
tc_setclock(&ts);
#ifdef FFCLOCK
ffclock_reset_clock(&ts);
#endif
return;
wrong_time:
if (base > 0) {
ts.tv_sec = base;
ts.tv_nsec = 0;
tc_setclock(&ts);
}
}
/*
* Write system time back to RTC
*/
void
resettodr(void)
{
struct timespec ts;
int error;
if (disable_rtc_set || clock_dev == NULL)
return;
mtx_lock(&resettodr_lock);
getnanotime(&ts);
timespecadd(&ts, &clock_adj);
ts.tv_sec -= utc_offset();
/* XXX: We should really set all registered RTCs */
error = CLOCK_SETTIME(clock_dev, &ts);
mtx_unlock(&resettodr_lock);
if (error != 0)
printf("warning: clock_settime failed (%d), time-of-day clock "
"not adjusted to system time\n", error);
}