tick.c

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    1 /*-
    2  * Copyright (c) 2001 Jake Burkholder.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  *
   26  * $FreeBSD: releng/5.2/sys/sparc64/sparc64/tick.c 119291 2003-08-22 07:39:05Z imp $
   27  */
   28 
   29 #include <sys/param.h>
   30 #include <sys/kernel.h>
   31 #include <sys/systm.h>
   32 #include <sys/bus.h>
   33 #include <sys/interrupt.h>
   34 #include <sys/pcpu.h>
   35 #include <sys/timetc.h>
   36 #ifdef SMP
   37 #include <sys/ktr.h>
   38 #include <sys/lock.h>
   39 #include <sys/mutex.h>
   40 #include <sys/proc.h>
   41 #endif
   42 
   43 #include <dev/ofw/openfirm.h>
   44 
   45 #include <machine/clock.h>
   46 #include <machine/frame.h>
   47 #include <machine/intr_machdep.h>
   48 #include <machine/tick.h>
   49 #include <machine/ver.h>
   50 #ifdef SMP
   51 #include <machine/cpu.h>
   52 #endif
   53 
   54 int tick_missed;        /* statistics */
   55 
   56 #define TICK_GRACE      10000
   57 
   58 void
   59 cpu_initclocks(void)
   60 {
   61         stathz = hz;
   62         tick_start(tick_hardclock);
   63 }
   64 
   65 static __inline void
   66 tick_process(struct clockframe *cf)
   67 {
   68 
   69         if (PCPU_GET(cpuid) == 0)
   70                 hardclock(cf);
   71         else
   72                 hardclock_process(cf);
   73         if (profprocs != 0)
   74                 profclock(cf);
   75         statclock(cf);
   76 }
   77 
   78 void
   79 tick_hardclock(struct clockframe *cf)
   80 {
   81         int missed;
   82         u_long next;
   83         register_t i;
   84 
   85         tick_process(cf);
   86         /*
   87          * Avoid stopping of hardclock in case we missed one tick period by
   88          * ensuring that the the value of the next tick is at least TICK_GRACE
   89          * ticks in the future.
   90          * Missed ticks need to be accounted for by repeatedly calling
   91          * hardclock.
   92          */
   93         missed = 0;
   94         next = rd(asr23) + tick_increment;
   95         i = intr_disable();
   96         while (next < rd(tick) + TICK_GRACE) {
   97                 next += tick_increment;
   98                 missed++;
   99         }
  100         wr(asr23, next, 0);
  101         intr_restore(i);
  102         atomic_add_int(&tick_missed, missed);
  103         for (; missed > 0; missed--)
  104                 tick_process(cf);
  105 }
  106 
  107 void
  108 tick_init(u_long clock)
  109 {
  110         tick_freq = clock;
  111         tick_MHz = clock / 1000000;
  112         tick_increment = clock / hz;
  113 }
  114 
  115 void
  116 tick_start(tick_func_t *func)
  117 {
  118         intr_setup(PIL_TICK, (ih_func_t *)func, -1, NULL, NULL);
  119         wrpr(tick, 0, 0);
  120         wr(asr23, tick_increment, 0);
  121 }
  122 
  123 #ifdef SMP
  124 void
  125 tick_start_ap(void)
  126 {
  127         u_long base;
  128 
  129         /*
  130          * Try to make the ticks interrupt as synchronously as possible to
  131          * avoid inaccuracies for migrating processes. Leave out one tick to
  132          * make sure that it is not missed.
  133          */
  134         base = rd(tick);
  135         wr(asr23, roundup(base, tick_increment) + tick_increment, 0);
  136 }
  137 #endif
  138 
  139 void
  140 tick_stop(void)
  141 {
  142 
  143         if (cpu_impl >= CPU_IMPL_ULTRASPARCIII)
  144                 wr(asr24, 1L << 63, 0);
  145         wr(asr23, 1L << 63, 0);
  146 }

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FreeBSD/Linux Kernel Cross Reference sys/sparc64/sparc64/tick.c

FreeBSD/Linux Kernel Cross Reference
sys/sparc64/sparc64/tick.c