[src/simonb-timecounters]: src/sys/arch/i386/i386 Pull up from HEAD.

[simonb <simonb%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c1928b8dbf59
branches:  simonb-timecounters
changeset: 587786:c1928b8dbf59
user:      simonb <simonb%NetBSD.org@localhost>
date:      Sat Feb 04 11:10:42 2006 +0000

description:
Pull up from HEAD.

diffstat:

 sys/arch/i386/i386/tsc.c |  154 +++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 154 insertions(+), 0 deletions(-)

diffs (158 lines):

diff -r 9588d4af478b -r c1928b8dbf59 sys/arch/i386/i386/tsc.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/arch/i386/i386/tsc.c  Sat Feb 04 11:10:42 2006 +0000
@@ -0,0 +1,154 @@
+/*-
+ * 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: src/sys/i386/i386/tsc.c,v 1.204 2003/10/21 18:28:34 silby Exp $");
+
+#include "opt_clock.h"
+
+#include <sys/param.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>
+
+uint64_t       tsc_freq;
+int            tsc_is_broken;
+u_int          tsc_present;
+
+#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 unsigned tsc_get_timecount(struct timecounter *tc);
+
+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);
+}
+
+
+void
+init_TSC_tc(void)
+{
+       /*
+        * 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 looses 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_present && tsc_freq != 0 && !tsc_is_broken) {
+               tsc_timecounter.tc_frequency = tsc_freq;
+               tc_init(&tsc_timecounter);
+       }
+}
+
+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_int(oidp, &freq, sizeof(freq), 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, sizeof(u_int), sysctl_machdep_tsc_freq, "IU", "");
+
+static unsigned
+tsc_get_timecount(struct timecounter *tc)
+{
+       return (rdtsc());
+}