os161/kern/dev/generic/rtclock.c
2015-12-23 00:50:04 +00:00

71 lines
2.5 KiB
C

/*
* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
* The President and Fellows of Harvard College.
*
* 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 UNIVERSITY 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 UNIVERSITY 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.
*/
/*
* Machine-independent generic clock "device".
*
* Basically, all we do is remember something that can be used for
* handling requests for the current time, and provide the gettime()
* function to the rest of the kernel.
*
* The kernel config mechanism can be used to explicitly choose which
* of the available clocks to use, if more than one is available.
*
* The system will panic if gettime() is called and there is no clock.
*/
#include <types.h>
#include <kern/errno.h>
#include <lib.h>
#include <clock.h>
#include <generic/rtclock.h>
#include "autoconf.h"
static struct rtclock_softc *the_clock = NULL;
int
config_rtclock(struct rtclock_softc *rtc, int unit)
{
/* We use only the first clock device. */
if (unit!=0) {
return ENODEV;
}
KASSERT(the_clock==NULL);
the_clock = rtc;
return 0;
}
void
gettime(struct timespec *ts)
{
KASSERT(the_clock!=NULL);
the_clock->rtc_gettime(the_clock->rtc_devdata, ts);
}