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/*-
* Copyright (c) 1998-2003 Poul-Henning Kamp
* All rights reserved.
*
* 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 "opt_clock.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/cpu.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/timetc.h>
#include <sys/kernel.h>
#include <sys/power.h>
#include <sys/smp.h>
#include <machine/clock.h>
#include <machine/md_var.h>
#include <machine/specialreg.h>
#include "cpufreq_if.h"
uint64_t tsc_freq;
int tsc_is_broken;
int tsc_is_invariant;
static eventhandler_tag tsc_levels_tag, tsc_pre_tag, tsc_post_tag;
SYSCTL_INT(_kern_timecounter, OID_AUTO, invariant_tsc, CTLFLAG_RDTUN,
&tsc_is_invariant, 0, "Indicates whether the TSC is P-state invariant");
TUNABLE_INT("kern.timecounter.invariant_tsc", &tsc_is_invariant);
#ifdef SMP
static int smp_tsc;
SYSCTL_INT(_kern_timecounter, OID_AUTO, smp_tsc, CTLFLAG_RDTUN, &smp_tsc, 0,
"Indicates whether the TSC is safe to use in SMP mode");
TUNABLE_INT("kern.timecounter.smp_tsc", &smp_tsc);
#endif
static void tsc_freq_changed(void *arg, const struct cf_level *level,
int status);
static void tsc_freq_changing(void *arg, const struct cf_level *level,
int *status);
static unsigned tsc_get_timecount(struct timecounter *tc);
static void tsc_levels_changed(void *arg, int unit);
static struct timecounter tsc_timecounter = {
tsc_get_timecount, /* get_timecount */
0, /* no poll_pps */
~0u, /* counter_mask */
0, /* frequency */
"TSC", /* name */
800, /* quality (adjusted in code) */
};
void
init_TSC(void)
{
u_int64_t tscval[2];
if (bootverbose)
printf("Calibrating TSC clock ... ");
tscval[0] = rdtsc();
DELAY(1000000);
tscval[1] = rdtsc();
tsc_freq = tscval[1] - tscval[0];
if (bootverbose)
printf("TSC clock: %lu Hz\n", tsc_freq);
/*
* Inform CPU accounting about our boot-time clock rate. Once the
* system is finished booting, we will get the real max clock rate
* via tsc_freq_max(). This also will be updated if someone loads
* a cpufreq driver after boot that discovers a new max frequency.
*/
set_cputicker(rdtsc, tsc_freq, 1);
/* Register to find out about changes in CPU frequency. */
tsc_pre_tag = EVENTHANDLER_REGISTER(cpufreq_pre_change,
tsc_freq_changing, NULL, EVENTHANDLER_PRI_FIRST);
tsc_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change,
tsc_freq_changed, NULL, EVENTHANDLER_PRI_FIRST);
tsc_levels_tag = EVENTHANDLER_REGISTER(cpufreq_levels_changed,
tsc_levels_changed, NULL, EVENTHANDLER_PRI_ANY);
}
void
init_TSC_tc(void)
{
#ifdef SMP
/*
* We can not use the TSC in SMP mode unless the TSCs on all CPUs
* are somehow synchronized. Some hardware configurations do
* this, but we have no way of determining whether this is the
* case, so we do not use the TSC in multi-processor systems
* unless the user indicated (by setting kern.timecounter.smp_tsc
* to 1) that he believes that his TSCs are synchronized.
*/
if (mp_ncpus > 1 && !smp_tsc)
tsc_timecounter.tc_quality = -100;
#endif
if (tsc_freq != 0 && !tsc_is_broken) {
tsc_timecounter.tc_frequency = tsc_freq;
tc_init(&tsc_timecounter);
}
}
/*
* When cpufreq levels change, find out about the (new) max frequency. We
* use this to update CPU accounting in case it got a lower estimate at boot.
*/
static void
tsc_levels_changed(void *arg, int unit)
{
device_t cf_dev;
struct cf_level *levels;
int count, error;
uint64_t max_freq;
/* Only use values from the first CPU, assuming all are equal. */
if (unit != 0)
return;
/* Find the appropriate cpufreq device instance. */
cf_dev = devclass_get_device(devclass_find("cpufreq"), unit);
if (cf_dev == NULL) {
printf("tsc_levels_changed() called but no cpufreq device?\n");
return;
}
/* Get settings from the device and find the max frequency. */
count = 64;
levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT);
if (levels == NULL)
return;
error = CPUFREQ_LEVELS(cf_dev, levels, &count);
if (error == 0 && count != 0) {
max_freq = (uint64_t)levels[0].total_set.freq * 1000000;
set_cputicker(rdtsc, max_freq, 1);
} else
printf("tsc_levels_changed: no max freq found\n");
free(levels, M_TEMP);
}
/*
* If the TSC timecounter is in use, veto the pending change. It may be
* possible in the future to handle a dynamically-changing timecounter rate.
*/
static void
tsc_freq_changing(void *arg, const struct cf_level *level, int *status)
{
if (*status != 0 || timecounter != &tsc_timecounter ||
tsc_is_invariant)
return;
printf("timecounter TSC must not be in use when "
"changing frequencies; change denied\n");
*status = EBUSY;
}
/* Update TSC freq with the value indicated by the caller. */
static void
tsc_freq_changed(void *arg, const struct cf_level *level, int status)
{
/*
* If there was an error during the transition or
* TSC is P-state invariant, don't do anything.
*/
if (status != 0 || tsc_is_invariant)
return;
/* Total setting for this level gives the new frequency in MHz. */
tsc_freq = (uint64_t)level->total_set.freq * 1000000;
tsc_timecounter.tc_frequency = tsc_freq;
}
static int
sysctl_machdep_tsc_freq(SYSCTL_HANDLER_ARGS)
{
int error;
uint64_t freq;
if (tsc_timecounter.tc_frequency == 0)
return (EOPNOTSUPP);
freq = tsc_freq;
error = sysctl_handle_quad(oidp, &freq, 0, req);
if (error == 0 && req->newptr != NULL) {
tsc_freq = freq;
tsc_timecounter.tc_frequency = tsc_freq;
}
return (error);
}
SYSCTL_PROC(_machdep, OID_AUTO, tsc_freq, CTLTYPE_QUAD | CTLFLAG_RW,
0, 0, sysctl_machdep_tsc_freq, "QU", "");
static unsigned
tsc_get_timecount(struct timecounter *tc)
{
return (rdtsc());
}
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