Import main FreeBSD timecounter support files as of 4th Feb 2006.
This commit is contained in:
simonb
parent
fe78fe0b46
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/*-
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD: src/sys/kern/kern_tc.c,v 1.166 2005/09/19 22:16:31 andre Exp $");
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#include "opt_ntp.h"
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/syslog.h>
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#include <sys/systm.h>
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#include <sys/timepps.h>
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#include <sys/timetc.h>
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#include <sys/timex.h>
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/*
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* A large step happens on boot. This constant detects such steps.
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* It is relatively small so that ntp_update_second gets called enough
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* in the typical 'missed a couple of seconds' case, but doesn't loop
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* forever when the time step is large.
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*/
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#define LARGE_STEP 200
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/*
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* Implement a dummy timecounter which we can use until we get a real one
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* in the air. This allows the console and other early stuff to use
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* time services.
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*/
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static u_int
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dummy_get_timecount(struct timecounter *tc)
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{
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static u_int now;
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return (++now);
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}
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static struct timecounter dummy_timecounter = {
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dummy_get_timecount, 0, ~0u, 1000000, "dummy", -1000000
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};
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struct timehands {
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/* These fields must be initialized by the driver. */
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struct timecounter *th_counter;
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int64_t th_adjustment;
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u_int64_t th_scale;
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u_int th_offset_count;
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struct bintime th_offset;
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struct timeval th_microtime;
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struct timespec th_nanotime;
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/* Fields not to be copied in tc_windup start with th_generation. */
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volatile u_int th_generation;
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struct timehands *th_next;
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};
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static struct timehands th0;
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static struct timehands th9 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th0};
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static struct timehands th8 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th9};
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static struct timehands th7 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th8};
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static struct timehands th6 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th7};
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static struct timehands th5 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th6};
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static struct timehands th4 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th5};
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static struct timehands th3 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th4};
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static struct timehands th2 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th3};
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static struct timehands th1 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th2};
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static struct timehands th0 = {
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&dummy_timecounter,
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0,
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(uint64_t)-1 / 1000000,
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0,
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{1, 0},
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{0, 0},
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{0, 0},
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1,
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&th1
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};
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static struct timehands *volatile timehands = &th0;
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struct timecounter *timecounter = &dummy_timecounter;
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static struct timecounter *timecounters = &dummy_timecounter;
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time_t time_second = 1;
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time_t time_uptime = 1;
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static struct bintime boottimebin;
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struct timeval boottime;
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static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS);
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SYSCTL_PROC(_kern, KERN_BOOTTIME, boottime, CTLTYPE_STRUCT|CTLFLAG_RD,
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NULL, 0, sysctl_kern_boottime, "S,timeval", "System boottime");
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SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, "");
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static int timestepwarnings;
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SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW,
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×tepwarnings, 0, "");
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#define TC_STATS(foo) \
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static u_int foo; \
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SYSCTL_UINT(_kern_timecounter, OID_AUTO, foo, CTLFLAG_RD, &foo, 0, "");\
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struct __hack
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TC_STATS(nbinuptime); TC_STATS(nnanouptime); TC_STATS(nmicrouptime);
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TC_STATS(nbintime); TC_STATS(nnanotime); TC_STATS(nmicrotime);
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TC_STATS(ngetbinuptime); TC_STATS(ngetnanouptime); TC_STATS(ngetmicrouptime);
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TC_STATS(ngetbintime); TC_STATS(ngetnanotime); TC_STATS(ngetmicrotime);
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TC_STATS(nsetclock);
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#undef TC_STATS
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static void tc_windup(void);
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static int
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sysctl_kern_boottime(SYSCTL_HANDLER_ARGS)
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{
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#ifdef SCTL_MASK32
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int tv[2];
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if (req->flags & SCTL_MASK32) {
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tv[0] = boottime.tv_sec;
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tv[1] = boottime.tv_usec;
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return SYSCTL_OUT(req, tv, sizeof(tv));
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} else
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#endif
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return SYSCTL_OUT(req, &boottime, sizeof(boottime));
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}
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/*
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* Return the difference between the timehands' counter value now and what
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* was when we copied it to the timehands' offset_count.
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*/
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static __inline u_int
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tc_delta(struct timehands *th)
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{
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struct timecounter *tc;
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tc = th->th_counter;
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return ((tc->tc_get_timecount(tc) - th->th_offset_count) &
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tc->tc_counter_mask);
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}
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/*
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* Functions for reading the time. We have to loop until we are sure that
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* the timehands that we operated on was not updated under our feet. See
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* the comment in <sys/time.h> for a description of these 12 functions.
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*/
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void
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binuptime(struct bintime *bt)
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{
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struct timehands *th;
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u_int gen;
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nbinuptime++;
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do {
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th = timehands;
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gen = th->th_generation;
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*bt = th->th_offset;
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bintime_addx(bt, th->th_scale * tc_delta(th));
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} while (gen == 0 || gen != th->th_generation);
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}
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void
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nanouptime(struct timespec *tsp)
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{
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struct bintime bt;
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nnanouptime++;
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binuptime(&bt);
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bintime2timespec(&bt, tsp);
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}
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void
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microuptime(struct timeval *tvp)
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{
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struct bintime bt;
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nmicrouptime++;
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binuptime(&bt);
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bintime2timeval(&bt, tvp);
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}
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void
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bintime(struct bintime *bt)
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{
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nbintime++;
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binuptime(bt);
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bintime_add(bt, &boottimebin);
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}
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void
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nanotime(struct timespec *tsp)
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{
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struct bintime bt;
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nnanotime++;
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bintime(&bt);
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bintime2timespec(&bt, tsp);
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}
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void
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microtime(struct timeval *tvp)
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{
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struct bintime bt;
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nmicrotime++;
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bintime(&bt);
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bintime2timeval(&bt, tvp);
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}
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void
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getbinuptime(struct bintime *bt)
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{
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struct timehands *th;
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u_int gen;
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ngetbinuptime++;
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do {
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th = timehands;
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gen = th->th_generation;
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*bt = th->th_offset;
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} while (gen == 0 || gen != th->th_generation);
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}
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void
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getnanouptime(struct timespec *tsp)
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{
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struct timehands *th;
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u_int gen;
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ngetnanouptime++;
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do {
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th = timehands;
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gen = th->th_generation;
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bintime2timespec(&th->th_offset, tsp);
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} while (gen == 0 || gen != th->th_generation);
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}
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void
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getmicrouptime(struct timeval *tvp)
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{
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struct timehands *th;
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u_int gen;
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ngetmicrouptime++;
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do {
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th = timehands;
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gen = th->th_generation;
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bintime2timeval(&th->th_offset, tvp);
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} while (gen == 0 || gen != th->th_generation);
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}
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void
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getbintime(struct bintime *bt)
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{
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struct timehands *th;
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u_int gen;
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ngetbintime++;
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do {
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th = timehands;
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gen = th->th_generation;
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*bt = th->th_offset;
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} while (gen == 0 || gen != th->th_generation);
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bintime_add(bt, &boottimebin);
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}
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void
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getnanotime(struct timespec *tsp)
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{
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struct timehands *th;
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u_int gen;
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ngetnanotime++;
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do {
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th = timehands;
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gen = th->th_generation;
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*tsp = th->th_nanotime;
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} while (gen == 0 || gen != th->th_generation);
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}
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void
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getmicrotime(struct timeval *tvp)
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{
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struct timehands *th;
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u_int gen;
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ngetmicrotime++;
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do {
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th = timehands;
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gen = th->th_generation;
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*tvp = th->th_microtime;
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} while (gen == 0 || gen != th->th_generation);
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}
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/*
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* Initialize a new timecounter and possibly use it.
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*/
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void
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tc_init(struct timecounter *tc)
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{
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u_int u;
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u = tc->tc_frequency / tc->tc_counter_mask;
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/* XXX: We need some margin here, 10% is a guess */
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u *= 11;
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u /= 10;
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if (u > hz && tc->tc_quality >= 0) {
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tc->tc_quality = -2000;
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if (bootverbose) {
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printf("Timecounter \"%s\" frequency %ju Hz",
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tc->tc_name, (uintmax_t)tc->tc_frequency);
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printf(" -- Insufficient hz, needs at least %u\n", u);
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}
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} else if (tc->tc_quality >= 0 || bootverbose) {
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printf("Timecounter \"%s\" frequency %ju Hz quality %d\n",
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tc->tc_name, (uintmax_t)tc->tc_frequency,
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tc->tc_quality);
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}
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tc->tc_next = timecounters;
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timecounters = tc;
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/*
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* Never automatically use a timecounter with negative quality.
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* Even though we run on the dummy counter, switching here may be
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* worse since this timecounter may not be monotonous.
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*/
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if (tc->tc_quality < 0)
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return;
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if (tc->tc_quality < timecounter->tc_quality)
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return;
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if (tc->tc_quality == timecounter->tc_quality &&
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tc->tc_frequency < timecounter->tc_frequency)
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return;
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(void)tc->tc_get_timecount(tc);
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(void)tc->tc_get_timecount(tc);
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timecounter = tc;
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}
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/* Report the frequency of the current timecounter. */
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u_int64_t
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tc_getfrequency(void)
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{
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return (timehands->th_counter->tc_frequency);
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}
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/*
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* Step our concept of UTC. This is done by modifying our estimate of
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* when we booted.
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* XXX: not locked.
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*/
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void
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tc_setclock(struct timespec *ts)
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{
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struct timespec ts2;
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struct bintime bt, bt2;
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nsetclock++;
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binuptime(&bt2);
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timespec2bintime(ts, &bt);
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bintime_sub(&bt, &bt2);
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bintime_add(&bt2, &boottimebin);
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boottimebin = bt;
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bintime2timeval(&bt, &boottime);
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/* XXX fiddle all the little crinkly bits around the fiords... */
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tc_windup();
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if (timestepwarnings) {
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bintime2timespec(&bt2, &ts2);
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log(LOG_INFO, "Time stepped from %jd.%09ld to %jd.%09ld\n",
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(intmax_t)ts2.tv_sec, ts2.tv_nsec,
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(intmax_t)ts->tv_sec, ts->tv_nsec);
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}
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}
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/*
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* Initialize the next struct timehands in the ring and make
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* it the active timehands. Along the way we might switch to a different
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* timecounter and/or do seconds processing in NTP. Slightly magic.
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*/
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static void
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tc_windup(void)
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{
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struct bintime bt;
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struct timehands *th, *tho;
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u_int64_t scale;
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u_int delta, ncount, ogen;
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int i;
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time_t t;
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/*
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* Make the next timehands a copy of the current one, but do not
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* overwrite the generation or next pointer. While we update
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* the contents, the generation must be zero.
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*/
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tho = timehands;
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th = tho->th_next;
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ogen = th->th_generation;
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th->th_generation = 0;
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bcopy(tho, th, offsetof(struct timehands, th_generation));
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/*
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* Capture a timecounter delta on the current timecounter and if
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* changing timecounters, a counter value from the new timecounter.
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* Update the offset fields accordingly.
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*/
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delta = tc_delta(th);
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if (th->th_counter != timecounter)
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ncount = timecounter->tc_get_timecount(timecounter);
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else
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ncount = 0;
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th->th_offset_count += delta;
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th->th_offset_count &= th->th_counter->tc_counter_mask;
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bintime_addx(&th->th_offset, th->th_scale * delta);
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/*
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* Hardware latching timecounters may not generate interrupts on
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* PPS events, so instead we poll them. There is a finite risk that
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* the hardware might capture a count which is later than the one we
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* got above, and therefore possibly in the next NTP second which might
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* have a different rate than the current NTP second. It doesn't
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* matter in practice.
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*/
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if (tho->th_counter->tc_poll_pps)
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tho->th_counter->tc_poll_pps(tho->th_counter);
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/*
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* Deal with NTP second processing. The for loop normally
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* iterates at most once, but in extreme situations it might
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* keep NTP sane if timeouts are not run for several seconds.
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* At boot, the time step can be large when the TOD hardware
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* has been read, so on really large steps, we call
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* ntp_update_second only twice. We need to call it twice in
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* case we missed a leap second.
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*/
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bt = th->th_offset;
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bintime_add(&bt, &boottimebin);
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i = bt.sec - tho->th_microtime.tv_sec;
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if (i > LARGE_STEP)
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i = 2;
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for (; i > 0; i--) {
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t = bt.sec;
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ntp_update_second(&th->th_adjustment, &bt.sec);
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if (bt.sec != t)
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boottimebin.sec += bt.sec - t;
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}
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/* Update the UTC timestamps used by the get*() functions. */
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/* XXX shouldn't do this here. Should force non-`get' versions. */
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bintime2timeval(&bt, &th->th_microtime);
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bintime2timespec(&bt, &th->th_nanotime);
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/* Now is a good time to change timecounters. */
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if (th->th_counter != timecounter) {
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th->th_counter = timecounter;
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th->th_offset_count = ncount;
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}
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/*-
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* Recalculate the scaling factor. We want the number of 1/2^64
|
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* fractions of a second per period of the hardware counter, taking
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* into account the th_adjustment factor which the NTP PLL/adjtime(2)
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* processing provides us with.
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*
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* The th_adjustment is nanoseconds per second with 32 bit binary
|
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* fraction and we want 64 bit binary fraction of second:
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*
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* x = a * 2^32 / 10^9 = a * 4.294967296
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*
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* The range of th_adjustment is +/- 5000PPM so inside a 64bit int
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* we can only multiply by about 850 without overflowing, but that
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* leaves suitably precise fractions for multiply before divide.
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*
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* Divide before multiply with a fraction of 2199/512 results in a
|
||||
* systematic undercompensation of 10PPM of th_adjustment. On a
|
||||
* 5000PPM adjustment this is a 0.05PPM error. This is acceptable.
|
||||
*
|
||||
* We happily sacrifice the lowest of the 64 bits of our result
|
||||
* to the goddess of code clarity.
|
||||
*
|
||||
*/
|
||||
scale = (u_int64_t)1 << 63;
|
||||
scale += (th->th_adjustment / 1024) * 2199;
|
||||
scale /= th->th_counter->tc_frequency;
|
||||
th->th_scale = scale * 2;
|
||||
|
||||
/*
|
||||
* Now that the struct timehands is again consistent, set the new
|
||||
* generation number, making sure to not make it zero.
|
||||
*/
|
||||
if (++ogen == 0)
|
||||
ogen = 1;
|
||||
th->th_generation = ogen;
|
||||
|
||||
/* Go live with the new struct timehands. */
|
||||
time_second = th->th_microtime.tv_sec;
|
||||
time_uptime = th->th_offset.sec;
|
||||
timehands = th;
|
||||
}
|
||||
|
||||
/* Report or change the active timecounter hardware. */
|
||||
static int
|
||||
sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS)
|
||||
{
|
||||
char newname[32];
|
||||
struct timecounter *newtc, *tc;
|
||||
int error;
|
||||
|
||||
tc = timecounter;
|
||||
strlcpy(newname, tc->tc_name, sizeof(newname));
|
||||
|
||||
error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req);
|
||||
if (error != 0 || req->newptr == NULL ||
|
||||
strcmp(newname, tc->tc_name) == 0)
|
||||
return (error);
|
||||
for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) {
|
||||
if (strcmp(newname, newtc->tc_name) != 0)
|
||||
continue;
|
||||
|
||||
/* Warm up new timecounter. */
|
||||
(void)newtc->tc_get_timecount(newtc);
|
||||
(void)newtc->tc_get_timecount(newtc);
|
||||
|
||||
timecounter = newtc;
|
||||
return (0);
|
||||
}
|
||||
return (EINVAL);
|
||||
}
|
||||
|
||||
SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING | CTLFLAG_RW,
|
||||
0, 0, sysctl_kern_timecounter_hardware, "A", "");
|
||||
|
||||
|
||||
/* Report or change the active timecounter hardware. */
|
||||
static int
|
||||
sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS)
|
||||
{
|
||||
char buf[32], *spc;
|
||||
struct timecounter *tc;
|
||||
int error;
|
||||
|
||||
spc = "";
|
||||
error = 0;
|
||||
for (tc = timecounters; error == 0 && tc != NULL; tc = tc->tc_next) {
|
||||
sprintf(buf, "%s%s(%d)",
|
||||
spc, tc->tc_name, tc->tc_quality);
|
||||
error = SYSCTL_OUT(req, buf, strlen(buf));
|
||||
spc = " ";
|
||||
}
|
||||
return (error);
|
||||
}
|
||||
|
||||
SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice, CTLTYPE_STRING | CTLFLAG_RD,
|
||||
0, 0, sysctl_kern_timecounter_choice, "A", "");
|
||||
|
||||
/*
|
||||
* RFC 2783 PPS-API implementation.
|
||||
*/
|
||||
|
||||
int
|
||||
pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
|
||||
{
|
||||
pps_params_t *app;
|
||||
struct pps_fetch_args *fapi;
|
||||
#ifdef PPS_SYNC
|
||||
struct pps_kcbind_args *kapi;
|
||||
#endif
|
||||
|
||||
KASSERT(pps != NULL, ("NULL pps pointer in pps_ioctl"));
|
||||
switch (cmd) {
|
||||
case PPS_IOC_CREATE:
|
||||
return (0);
|
||||
case PPS_IOC_DESTROY:
|
||||
return (0);
|
||||
case PPS_IOC_SETPARAMS:
|
||||
app = (pps_params_t *)data;
|
||||
if (app->mode & ~pps->ppscap)
|
||||
return (EINVAL);
|
||||
pps->ppsparam = *app;
|
||||
return (0);
|
||||
case PPS_IOC_GETPARAMS:
|
||||
app = (pps_params_t *)data;
|
||||
*app = pps->ppsparam;
|
||||
app->api_version = PPS_API_VERS_1;
|
||||
return (0);
|
||||
case PPS_IOC_GETCAP:
|
||||
*(int*)data = pps->ppscap;
|
||||
return (0);
|
||||
case PPS_IOC_FETCH:
|
||||
fapi = (struct pps_fetch_args *)data;
|
||||
if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
|
||||
return (EINVAL);
|
||||
if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec)
|
||||
return (EOPNOTSUPP);
|
||||
pps->ppsinfo.current_mode = pps->ppsparam.mode;
|
||||
fapi->pps_info_buf = pps->ppsinfo;
|
||||
return (0);
|
||||
case PPS_IOC_KCBIND:
|
||||
#ifdef PPS_SYNC
|
||||
kapi = (struct pps_kcbind_args *)data;
|
||||
/* XXX Only root should be able to do this */
|
||||
if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
|
||||
return (EINVAL);
|
||||
if (kapi->kernel_consumer != PPS_KC_HARDPPS)
|
||||
return (EINVAL);
|
||||
if (kapi->edge & ~pps->ppscap)
|
||||
return (EINVAL);
|
||||
pps->kcmode = kapi->edge;
|
||||
return (0);
|
||||
#else
|
||||
return (EOPNOTSUPP);
|
||||
#endif
|
||||
default:
|
||||
return (ENOIOCTL);
|
||||
}
|
||||
}
|
||||
|
||||
void
|
||||
pps_init(struct pps_state *pps)
|
||||
{
|
||||
pps->ppscap |= PPS_TSFMT_TSPEC;
|
||||
if (pps->ppscap & PPS_CAPTUREASSERT)
|
||||
pps->ppscap |= PPS_OFFSETASSERT;
|
||||
if (pps->ppscap & PPS_CAPTURECLEAR)
|
||||
pps->ppscap |= PPS_OFFSETCLEAR;
|
||||
}
|
||||
|
||||
void
|
||||
pps_capture(struct pps_state *pps)
|
||||
{
|
||||
struct timehands *th;
|
||||
|
||||
KASSERT(pps != NULL, ("NULL pps pointer in pps_capture"));
|
||||
th = timehands;
|
||||
pps->capgen = th->th_generation;
|
||||
pps->capth = th;
|
||||
pps->capcount = th->th_counter->tc_get_timecount(th->th_counter);
|
||||
if (pps->capgen != th->th_generation)
|
||||
pps->capgen = 0;
|
||||
}
|
||||
|
||||
void
|
||||
pps_event(struct pps_state *pps, int event)
|
||||
{
|
||||
struct bintime bt;
|
||||
struct timespec ts, *tsp, *osp;
|
||||
u_int tcount, *pcount;
|
||||
int foff, fhard;
|
||||
pps_seq_t *pseq;
|
||||
|
||||
KASSERT(pps != NULL, ("NULL pps pointer in pps_event"));
|
||||
/* If the timecounter was wound up underneath us, bail out. */
|
||||
if (pps->capgen == 0 || pps->capgen != pps->capth->th_generation)
|
||||
return;
|
||||
|
||||
/* Things would be easier with arrays. */
|
||||
if (event == PPS_CAPTUREASSERT) {
|
||||
tsp = &pps->ppsinfo.assert_timestamp;
|
||||
osp = &pps->ppsparam.assert_offset;
|
||||
foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
|
||||
fhard = pps->kcmode & PPS_CAPTUREASSERT;
|
||||
pcount = &pps->ppscount[0];
|
||||
pseq = &pps->ppsinfo.assert_sequence;
|
||||
} else {
|
||||
tsp = &pps->ppsinfo.clear_timestamp;
|
||||
osp = &pps->ppsparam.clear_offset;
|
||||
foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
|
||||
fhard = pps->kcmode & PPS_CAPTURECLEAR;
|
||||
pcount = &pps->ppscount[1];
|
||||
pseq = &pps->ppsinfo.clear_sequence;
|
||||
}
|
||||
|
||||
/*
|
||||
* If the timecounter changed, we cannot compare the count values, so
|
||||
* we have to drop the rest of the PPS-stuff until the next event.
|
||||
*/
|
||||
if (pps->ppstc != pps->capth->th_counter) {
|
||||
pps->ppstc = pps->capth->th_counter;
|
||||
*pcount = pps->capcount;
|
||||
pps->ppscount[2] = pps->capcount;
|
||||
return;
|
||||
}
|
||||
|
||||
/* Convert the count to a timespec. */
|
||||
tcount = pps->capcount - pps->capth->th_offset_count;
|
||||
tcount &= pps->capth->th_counter->tc_counter_mask;
|
||||
bt = pps->capth->th_offset;
|
||||
bintime_addx(&bt, pps->capth->th_scale * tcount);
|
||||
bintime_add(&bt, &boottimebin);
|
||||
bintime2timespec(&bt, &ts);
|
||||
|
||||
/* If the timecounter was wound up underneath us, bail out. */
|
||||
if (pps->capgen != pps->capth->th_generation)
|
||||
return;
|
||||
|
||||
*pcount = pps->capcount;
|
||||
(*pseq)++;
|
||||
*tsp = ts;
|
||||
|
||||
if (foff) {
|
||||
timespecadd(tsp, osp);
|
||||
if (tsp->tv_nsec < 0) {
|
||||
tsp->tv_nsec += 1000000000;
|
||||
tsp->tv_sec -= 1;
|
||||
}
|
||||
}
|
||||
#ifdef PPS_SYNC
|
||||
if (fhard) {
|
||||
u_int64_t scale;
|
||||
|
||||
/*
|
||||
* Feed the NTP PLL/FLL.
|
||||
* The FLL wants to know how many (hardware) nanoseconds
|
||||
* elapsed since the previous event.
|
||||
*/
|
||||
tcount = pps->capcount - pps->ppscount[2];
|
||||
pps->ppscount[2] = pps->capcount;
|
||||
tcount &= pps->capth->th_counter->tc_counter_mask;
|
||||
scale = (u_int64_t)1 << 63;
|
||||
scale /= pps->capth->th_counter->tc_frequency;
|
||||
scale *= 2;
|
||||
bt.sec = 0;
|
||||
bt.frac = 0;
|
||||
bintime_addx(&bt, scale * tcount);
|
||||
bintime2timespec(&bt, &ts);
|
||||
hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec);
|
||||
}
|
||||
#endif
|
||||
}
|
||||
|
||||
/*
|
||||
* Timecounters need to be updated every so often to prevent the hardware
|
||||
* counter from overflowing. Updating also recalculates the cached values
|
||||
* used by the get*() family of functions, so their precision depends on
|
||||
* the update frequency.
|
||||
*/
|
||||
|
||||
static int tc_tick;
|
||||
SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0, "");
|
||||
|
||||
void
|
||||
tc_ticktock(void)
|
||||
{
|
||||
static int count;
|
||||
|
||||
if (++count < tc_tick)
|
||||
return;
|
||||
count = 0;
|
||||
tc_windup();
|
||||
}
|
||||
|
||||
static void
|
||||
inittimecounter(void *dummy)
|
||||
{
|
||||
u_int p;
|
||||
|
||||
/*
|
||||
* Set the initial timeout to
|
||||
* max(1, <approx. number of hardclock ticks in a millisecond>).
|
||||
* People should probably not use the sysctl to set the timeout
|
||||
* to smaller than its inital value, since that value is the
|
||||
* smallest reasonable one. If they want better timestamps they
|
||||
* should use the non-"get"* functions.
|
||||
*/
|
||||
if (hz > 1000)
|
||||
tc_tick = (hz + 500) / 1000;
|
||||
else
|
||||
tc_tick = 1;
|
||||
p = (tc_tick * 1000000) / hz;
|
||||
printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000);
|
||||
|
||||
/* warm up new timecounter (again) and get rolling. */
|
||||
(void)timecounter->tc_get_timecount(timecounter);
|
||||
(void)timecounter->tc_get_timecount(timecounter);
|
||||
}
|
||||
|
||||
SYSINIT(timecounter, SI_SUB_CLOCKS, SI_ORDER_SECOND, inittimecounter, NULL)
|
||||
|
|
@ -0,0 +1,78 @@
|
|||
/*-
|
||||
* ----------------------------------------------------------------------------
|
||||
* "THE BEER-WARE LICENSE" (Revision 42):
|
||||
* <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
|
||||
* can do whatever you want with this stuff. If we meet some day, and you think
|
||||
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
|
||||
* ----------------------------------------------------------------------------
|
||||
*
|
||||
* $FreeBSD: src/sys/sys/timetc.h,v 1.58 2003/08/16 08:23:52 phk Exp $
|
||||
*/
|
||||
|
||||
#ifndef _SYS_TIMETC_H_
|
||||
#define _SYS_TIMETC_H_
|
||||
|
||||
#ifndef _KERNEL
|
||||
#error "no user-serviceable parts inside"
|
||||
#endif
|
||||
|
||||
/*-
|
||||
* `struct timecounter' is the interface between the hardware which implements
|
||||
* a timecounter and the MI code which uses this to keep track of time.
|
||||
*
|
||||
* A timecounter is a binary counter which has two properties:
|
||||
* * it runs at a fixed, known frequency.
|
||||
* * it has sufficient bits to not roll over in less than approximately
|
||||
* max(2 msec, 2/HZ seconds). (The value 2 here is really 1 + delta,
|
||||
* for some indeterminate value of delta.)
|
||||
*/
|
||||
|
||||
struct timecounter;
|
||||
typedef u_int timecounter_get_t(struct timecounter *);
|
||||
typedef void timecounter_pps_t(struct timecounter *);
|
||||
|
||||
struct timecounter {
|
||||
timecounter_get_t *tc_get_timecount;
|
||||
/*
|
||||
* This function reads the counter. It is not required to
|
||||
* mask any unimplemented bits out, as long as they are
|
||||
* constant.
|
||||
*/
|
||||
timecounter_pps_t *tc_poll_pps;
|
||||
/*
|
||||
* This function is optional. It will be called whenever the
|
||||
* timecounter is rewound, and is intended to check for PPS
|
||||
* events. Normal hardware does not need it but timecounters
|
||||
* which latch PPS in hardware (like sys/pci/xrpu.c) do.
|
||||
*/
|
||||
u_int tc_counter_mask;
|
||||
/* This mask should mask off any unimplemented bits. */
|
||||
u_int64_t tc_frequency;
|
||||
/* Frequency of the counter in Hz. */
|
||||
char *tc_name;
|
||||
/* Name of the timecounter. */
|
||||
int tc_quality;
|
||||
/*
|
||||
* Used to determine if this timecounter is better than
|
||||
* another timecounter higher means better. Negative
|
||||
* means "only use at explicit request".
|
||||
*/
|
||||
|
||||
void *tc_priv;
|
||||
/* Pointer to the timecounter's private parts. */
|
||||
struct timecounter *tc_next;
|
||||
/* Pointer to the next timecounter. */
|
||||
};
|
||||
|
||||
extern struct timecounter *timecounter;
|
||||
|
||||
u_int64_t tc_getfrequency(void);
|
||||
void tc_init(struct timecounter *tc);
|
||||
void tc_setclock(struct timespec *ts);
|
||||
void tc_ticktock(void);
|
||||
|
||||
#ifdef SYSCTL_DECL
|
||||
SYSCTL_DECL(_kern_timecounter);
|
||||
#endif
|
||||
|
||||
#endif /* !_SYS_TIMETC_H_ */
|
||||
Loading…
Reference in New Issue