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/*-
* Copyright (c) 2011 The University of Melbourne
* All rights reserved.
*
* This software was 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/timeffc.h>
extern struct ffclock_estimate ffclock_estimate;
extern struct bintime ffclock_boottime;
/*
* Feed-forward clock absolute time. This should be the preferred way to read
* the feed-forward clock for "wall-clock" type time. The flags allow to compose
* various flavours of absolute time (e.g. with or without leap seconds taken
* into account). If valid pointers are provided, the ffcounter value and an
* upper bound on clock error associated with the bintime are provided.
* NOTE: use ffclock_convert_abs() to differ the conversion of a ffcounter value
* read earlier.
*/
void
ffclock_abstime(ffcounter *ffcount, struct bintime *bt,
struct bintime *error_bound, uint32_t flags)
{
struct ffclock_estimate cest;
ffcounter ffc;
ffcounter update_ffcount;
ffcounter ffdelta_error;
/* Get counter and corresponding time. */
if ((flags & FFCLOCK_FAST) == FFCLOCK_FAST)
ffclock_last_tick(&ffc, bt, flags);
else {
ffclock_read_counter(&ffc);
ffclock_convert_abs(ffc, bt, flags);
}
/* Current ffclock estimate, use update_ffcount as generation number. */
do {
update_ffcount = ffclock_estimate.update_ffcount;
bcopy(&ffclock_estimate, &cest, sizeof(struct ffclock_estimate));
} while (update_ffcount != ffclock_estimate.update_ffcount);
/*
* Leap second adjustment. Total as seen by synchronisation algorithm
* since it started. cest.leapsec_next is the ffcounter prediction of
* when the next leapsecond occurs.
*/
if ((flags & FFCLOCK_LEAPSEC) == FFCLOCK_LEAPSEC) {
bt->sec -= cest.leapsec_total;
if (ffc > cest.leapsec_next)
bt->sec -= cest.leapsec;
}
/* Boot time adjustment, for uptime/monotonic clocks. */
if ((flags & FFCLOCK_UPTIME) == FFCLOCK_UPTIME) {
bintime_sub(bt, &ffclock_boottime);
}
/* Compute error bound if a valid pointer has been passed. */
if (error_bound) {
ffdelta_error = ffc - cest.update_ffcount;
ffclock_convert_diff(ffdelta_error, error_bound);
/* 18446744073709 = int(2^64/1e12), err_bound_rate in [ps/s] */
bintime_mul(error_bound, cest.errb_rate *
(uint64_t)18446744073709LL);
/* 18446744073 = int(2^64 / 1e9), since err_abs in [ns] */
bintime_addx(error_bound, cest.errb_abs *
(uint64_t)18446744073LL);
}
if (ffcount)
*ffcount = ffc;
}
/*
* Feed-forward difference clock. This should be the preferred way to convert a
* time interval in ffcounter values into a time interval in seconds. If a valid
* pointer is passed, an upper bound on the error in computing the time interval
* in seconds is provided.
*/
void
ffclock_difftime(ffcounter ffdelta, struct bintime *bt,
struct bintime *error_bound)
{
ffcounter update_ffcount;
uint32_t err_rate;
ffclock_convert_diff(ffdelta, bt);
if (error_bound) {
do {
update_ffcount = ffclock_estimate.update_ffcount;
err_rate = ffclock_estimate.errb_rate;
} while (update_ffcount != ffclock_estimate.update_ffcount);
ffclock_convert_diff(ffdelta, error_bound);
/* 18446744073709 = int(2^64/1e12), err_bound_rate in [ps/s] */
bintime_mul(error_bound, err_rate * (uint64_t)18446744073709LL);
}
}
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