Annotation of sys/arch/solbourne/solbourne/clock.c, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: clock.c,v 1.1 2005/04/19 21:30:18 miod Exp $ */
! 2: /* OpenBSD: clock.c,v 1.19 2004/04/08 01:11:21 deraadt Exp */
! 3:
! 4: /*
! 5: * Copyright (c) 1992, 1993
! 6: * The Regents of the University of California. All rights reserved.
! 7: * Copyright (c) 1994 Gordon W. Ross
! 8: * Copyright (c) 1993 Adam Glass
! 9: * Copyright (c) 1996 Paul Kranenburg
! 10: * Copyright (c) 1996
! 11: * The President and Fellows of Harvard College. All rights reserved.
! 12: *
! 13: * This software was developed by the Computer Systems Engineering group
! 14: * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
! 15: * contributed to Berkeley.
! 16: *
! 17: * All advertising materials mentioning features or use of this software
! 18: * must display the following acknowledgement:
! 19: * This product includes software developed by Harvard University.
! 20: * This product includes software developed by the University of
! 21: * California, Lawrence Berkeley Laboratory.
! 22: *
! 23: * Redistribution and use in source and binary forms, with or without
! 24: * modification, are permitted provided that the following conditions
! 25: * are met:
! 26: *
! 27: * 1. Redistributions of source code must retain the above copyright
! 28: * notice, this list of conditions and the following disclaimer.
! 29: * 2. Redistributions in binary form must reproduce the above copyright
! 30: * notice, this list of conditions and the following disclaimer in the
! 31: * documentation and/or other materials provided with the distribution.
! 32: * 3. All advertising materials mentioning features or use of this software
! 33: * must display the following acknowledgement:
! 34: * This product includes software developed by the University of
! 35: * California, Berkeley and its contributors.
! 36: * This product includes software developed by Paul Kranenburg.
! 37: * This product includes software developed by Harvard University.
! 38: * 4. Neither the name of the University nor the names of its contributors
! 39: * may be used to endorse or promote products derived from this software
! 40: * without specific prior written permission.
! 41: *
! 42: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 43: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 44: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 45: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 46: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 47: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 48: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 49: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 50: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 51: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 52: * SUCH DAMAGE.
! 53: *
! 54: * @(#)clock.c 8.1 (Berkeley) 6/11/93
! 55: *
! 56: */
! 57:
! 58: /*
! 59: * Clock driver. This is the id prom and eeprom driver as well
! 60: * and includes the timer register functions too.
! 61: */
! 62:
! 63: #include <sys/param.h>
! 64: #include <sys/kernel.h>
! 65: #include <sys/device.h>
! 66: #include <sys/systm.h>
! 67:
! 68: #include <uvm/uvm_extern.h>
! 69:
! 70: #include <machine/autoconf.h>
! 71: #include <machine/cpu.h>
! 72:
! 73: #include <sparc/sparc/asm.h>
! 74: #include <machine/idt.h>
! 75: #include <machine/kap.h>
! 76:
! 77: /*
! 78: * Statistics clock interval and variance, in usec. Variance must be a
! 79: * power of two. Since this gives us an even number, not an odd number,
! 80: * we discard one case and compensate. That is, a variance of 1024 would
! 81: * give us offsets in [0..1023]. Instead, we take offsets in [1..1023].
! 82: * This is symmetric about the point 512, or statvar/2, and thus averages
! 83: * to that value (assuming uniform random numbers).
! 84: */
! 85: /* XXX fix comment to match value */
! 86: int statvar = 8192;
! 87: int statmin; /* statclock interval - 1/2*variance */
! 88:
! 89: int timerblurb = 10; /* Guess a value; used before clock is attached */
! 90:
! 91: /*
! 92: * Set up the real-time and statistics clocks. Leave stathz 0 only if
! 93: * no alternative timer is available.
! 94: *
! 95: * The frequencies of these clocks must be an even number of microseconds.
! 96: */
! 97: void
! 98: cpu_initclocks()
! 99: {
! 100: profhz = hz;
! 101: tick = 1000000 / hz;
! 102: }
! 103:
! 104: /*
! 105: * Dummy setstatclockrate(), since we know profhz==hz.
! 106: */
! 107: /* ARGSUSED */
! 108: void
! 109: setstatclockrate(newhz)
! 110: int newhz;
! 111: {
! 112: /* nothing */
! 113: }
! 114:
! 115: /*
! 116: * Level 10 (clock) interrupts.
! 117: */
! 118: int
! 119: clockintr(cap)
! 120: void *cap;
! 121: {
! 122: hardclock((struct clockframe *)cap);
! 123:
! 124: return (1);
! 125: }
! 126:
! 127: /*
! 128: * Level 14 (stat clock) interrupt handler.
! 129: */
! 130: int
! 131: statintr(cap)
! 132: void *cap;
! 133: {
! 134: #if 1
! 135: panic("level 14 interrupt");
! 136: #else
! 137: statclock((struct clockframe *)cap);
! 138: #endif
! 139:
! 140: return (1);
! 141: }
! 142:
! 143: /*
! 144: * Return the best possible estimate of the time in the timeval
! 145: * to which tvp points. We do this by returning the current time
! 146: * plus the amount of time since the last clock interrupt.
! 147: *
! 148: * Check that this time is no less than any previously-reported time,
! 149: * which could happen around the time of a clock adjustment. Just for
! 150: * fun, we guarantee that the time will be greater than the value
! 151: * obtained by a previous call.
! 152: */
! 153: void
! 154: microtime(tvp)
! 155: struct timeval *tvp;
! 156: {
! 157: int s;
! 158: static struct timeval lasttime;
! 159: static struct timeval oneusec = {0, 1};
! 160:
! 161: s = splhigh();
! 162: *tvp = time;
! 163: splx(s);
! 164:
! 165: if (timercmp(tvp, &lasttime, <=))
! 166: timeradd(&lasttime, &oneusec, tvp);
! 167:
! 168: lasttime = *tvp;
! 169: }
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