1 /* $NetBSD: clock.c,v 1.11 2006/09/11 15:07:50 gdamore Exp $ */ 2 /* 3 * Copyright (c) 1998 Darrin B. Jewell 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Darrin B. Jewell 17 * 4. The name of the author may not be used to endorse or promote products 18 * derived from this software without specific prior written permission 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.11 2006/09/11 15:07:50 gdamore Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/kernel.h> 38 #include <sys/tty.h> 39 #include <sys/device.h> 40 41 #include <machine/psl.h> 42 #include <machine/bus.h> 43 #include <machine/cpu.h> 44 45 #include <next68k/dev/clockreg.h> 46 #include <next68k/dev/intiovar.h> 47 48 #include <next68k/next68k/rtc.h> 49 #include <next68k/next68k/isr.h> 50 51 /* @@@ This is pretty bogus and will need fixing once 52 * things are working better. 53 * -- jewell@mit.edu 54 */ 55 56 /* 57 * Note that the value of delay_divisor is roughly 58 * 2048 / cpuspeed (where cpuspeed is in MHz) on 68020 59 * and 68030 systems. See clock.c for the delay 60 * calibration algorithm. 61 */ 62 int cpuspeed; /* relative cpu speed; XXX skewed on 68040 */ 63 int delay_divisor = 2048/25; /* delay constant */ 64 65 /* 66 * Calibrate the delay constant. 67 */ 68 void 69 next68k_calibrate_delay(void) 70 { 71 extern int delay_divisor; 72 73 /* @@@ write this once we know how to read 74 * a real time clock 75 */ 76 77 /* 78 * Sanity check the delay_divisor value. If we totally lost, 79 * assume a 25MHz CPU; 80 */ 81 if (delay_divisor == 0) 82 delay_divisor = 2048 / 25; 83 84 /* Calculate CPU speed. */ 85 cpuspeed = 2048 / delay_divisor; 86 } 87 88 int clock_intr(void *); 89 90 int 91 clock_intr(void *arg) 92 { 93 volatile struct timer_reg *timer; 94 int whilecount = 0; 95 96 if (!INTR_OCCURRED(NEXT_I_TIMER)) { 97 return(0); 98 } 99 100 do { 101 static int in_hardclock = 0; 102 int s; 103 104 timer = (volatile struct timer_reg *)IIOV(NEXT_P_TIMER); 105 timer->csr |= TIMER_REG_UPDATE; 106 107 if (! in_hardclock) { 108 in_hardclock = 1; 109 s = splclock (); 110 hardclock(arg); 111 splx(s); 112 in_hardclock = 0; 113 } 114 if (whilecount++ > 10) 115 panic ("whilecount"); 116 } while (INTR_OCCURRED(NEXT_I_TIMER)); 117 return(1); 118 } 119 120 /* 121 * Set up the real-time and statistics clocks. Leave stathz 0 only 122 * if no alternative timer is available. 123 * 124 * The frequencies of these clocks must be an even number of microseconds. 125 */ 126 void 127 cpu_initclocks(void) 128 { 129 int s, cnt; 130 volatile struct timer_reg *timer; 131 132 rtc_init(); 133 hz = 100; 134 s = splclock(); 135 timer = (volatile struct timer_reg *)IIOV(NEXT_P_TIMER); 136 cnt = 1000000/hz; /* usec timer */ 137 timer->csr = 0; 138 timer->msb = (cnt >> 8); 139 timer->lsb = cnt; 140 timer->csr = TIMER_REG_ENABLE|TIMER_REG_UPDATE; 141 isrlink_autovec(clock_intr, NULL, NEXT_I_IPL(NEXT_I_TIMER), 0, NULL); 142 INTR_ENABLE(NEXT_I_TIMER); 143 splx(s); 144 } 145 146 147 void 148 setstatclockrate(int newhz) 149 { 150 151 /* XXX should we do something here? XXX */ 152 } 153 154 /* @@@ update this to use the usec timer 155 * Darrin B Jewell <jewell@mit.edu> Sun Feb 8 05:01:02 1998 156 * XXX: Well, there is no more microtime. But if there is a hardware 157 * timer of any sort, it could be added. ENODOCS. gdamore. 158 */ 159 160