1 files changed, 281 insertions, 0 deletions
diff --git a/sys/x86/x86/tsc.c b/sys/x86/x86/tsc.c
new file mode 100644
index 0000000..ae2cba4
--- /dev/null
+++ b/sys/x86/x86/tsc.c
@@ -0,0 +1,281 @@
+/*-
+ * 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/cputypes.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;
+int		tsc_present;
+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 (cpu_feature & CPUID_TSC)
+		tsc_present = 1;
+	else
+		tsc_present = 0;
+
+	if (!tsc_present) 
+		return;
+
+	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: %ju Hz\n", (intmax_t)tsc_freq);
+
+	switch (cpu_vendor_id) {
+	case CPU_VENDOR_AMD:
+		if ((amd_pminfo & AMDPM_TSC_INVARIANT) ||
+		    CPUID_TO_FAMILY(cpu_id) >= 0x10 || cpu_id == 0x60fb2)
+			tsc_is_invariant = 1;
+		break;
+	case CPU_VENDOR_INTEL:
+		if ((amd_pminfo & AMDPM_TSC_INVARIANT) ||
+		    (CPUID_TO_FAMILY(cpu_id) == 0x6 &&
+		    CPUID_TO_MODEL(cpu_id) >= 0xe) ||
+		    (CPUID_TO_FAMILY(cpu_id) == 0xf &&
+		    CPUID_TO_MODEL(cpu_id) >= 0x3))
+			tsc_is_invariant = 1;
+		break;
+	case CPU_VENDOR_CENTAUR:
+		if (CPUID_TO_FAMILY(cpu_id) == 0x6 &&
+		    CPUID_TO_MODEL(cpu_id) >= 0xf &&
+		    (rdmsr(0x1203) & 0x100000000ULL) == 0)
+			tsc_is_invariant = 1;
+		break;
+	}
+
+	/*
+	 * Inform CPU accounting about our boot-time clock rate.  This will
+	 * be updated if someone loads a cpufreq driver after boot that
+	 * discovers a new max frequency.
+	 */
+	set_cputicker(rdtsc, tsc_freq, 1);
+
+	if (tsc_is_invariant)
+		return;
+
+	/* 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)
+{
+
+	if (!tsc_present) 
+		return;
+
+	/*
+	 * We can not use the TSC if we support APM.  Precise timekeeping
+	 * on an APM'ed machine is at best a fools pursuit, since 
+	 * any and all of the time spent in various SMM code can't 
+	 * be reliably accounted for.  Reading the RTC is your only
+	 * source of reliable time info.  The i8254 loses too, of course,
+	 * but we need to have some kind of time...
+	 * We don't know at this point whether APM is going to be used
+	 * or not, nor when it might be activated.  Play it safe.
+	 */
+	if (power_pm_get_type() == POWER_PM_TYPE_APM) {
+		tsc_timecounter.tc_quality = -1000;
+		if (bootverbose)
+			printf("TSC timecounter disabled: APM enabled.\n");
+	}
+
+#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)
+		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, don't do anything. */
+	if (status != 0)
+		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());
+}