1 /* $NetBSD: clock.c,v 1.10 2004/09/02 08:22:58 scw Exp $ */ 2 /* $OpenBSD: clock.c,v 1.3 1997/10/13 13:42:53 pefo Exp $ */ 3 4 /* 5 * Copyright (C) 1995, 1996 Wolfgang Solfrank. 6 * Copyright (C) 1995, 1996 TooLs GmbH. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by TooLs GmbH. 20 * 4. The name of TooLs GmbH may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 28 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 29 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 30 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 31 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 32 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 __KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.10 2004/09/02 08:22:58 scw Exp $"); 37 38 #include <sys/param.h> 39 #include <sys/kernel.h> 40 #include <sys/systm.h> 41 #include <sys/properties.h> 42 43 #include <machine/cpu.h> 44 45 #include <powerpc/spr.h> 46 47 /* 48 * Initially we assume a processor with a bus frequency of 12.5 MHz. 49 */ 50 static u_long ticks_per_sec; 51 static u_long ns_per_tick; 52 static long ticks_per_intr; 53 static volatile u_long lasttb; 54 static u_long ticksmissed; 55 static volatile int tickspending; 56 57 void decr_intr(struct clockframe *); /* called from trap_subr.S */ 58 void stat_intr(struct clockframe *); /* called from trap_subr.S */ 59 60 #ifdef FAST_STAT_CLOCK 61 /* Stat clock runs at ~ 1.5KHz */ 62 #define PERIOD_POWER 17 63 #define TCR_PERIOD TCR_FP_2_17 64 #else 65 /* Stat clock runs at ~ 95Hz */ 66 #define PERIOD_POWER 21 67 #define TCR_PERIOD TCR_FP_2_21 68 #endif 69 70 71 void 72 stat_intr(struct clockframe *frame) 73 { 74 extern u_long intrcnt[]; 75 76 mtspr(SPR_TSR, TSR_FIS); /* Clear TSR[FIS] */ 77 intrcnt[CNT_STATCLOCK]++; 78 statclock(frame); 79 } 80 81 void 82 decr_intr(struct clockframe *frame) 83 { 84 int pri; 85 long tick, xticks; 86 int nticks; 87 extern u_long intrcnt[]; 88 /* 89 * Check whether we are initialized. 90 */ 91 if (!ticks_per_intr) 92 return; 93 94 tick = mftbl(); 95 mtspr(SPR_TSR, TSR_PIS); /* Clear TSR[PIS] */ 96 /* 97 * lasttb is used during microtime. Set it to the virtual 98 * start of this tick interval. 99 */ 100 xticks = tick - lasttb; /* Number of TLB cycles since last exception */ 101 for (nticks = 0; xticks > ticks_per_intr; nticks++) 102 xticks -= ticks_per_intr; 103 lasttb = tick - xticks; 104 105 intrcnt[CNT_CLOCK]++; 106 pri = splclock(); 107 if (pri & SPL_CLOCK) { 108 tickspending += nticks; 109 ticksmissed+= nticks; 110 } else { 111 nticks += tickspending; 112 tickspending = 0; 113 114 /* 115 * Reenable interrupts 116 */ 117 asm volatile ("wrteei 1"); 118 119 /* 120 * Do standard timer interrupt stuff. 121 * Do softclock stuff only on the last iteration. 122 */ 123 frame->pri = pri | SINT_CLOCK; 124 while (--nticks > 0) 125 hardclock(frame); 126 frame->pri = pri; 127 hardclock(frame); 128 } 129 splx(pri); 130 } 131 132 void 133 cpu_initclocks(void) 134 { 135 136 ticks_per_intr = ticks_per_sec / hz; 137 stathz = profhz = ticks_per_sec / (1 << PERIOD_POWER); 138 printf("Setting PIT to %ld/%d = %ld\n", ticks_per_sec, hz, ticks_per_intr); 139 lasttb = mftbl(); 140 mtspr(SPR_PIT, ticks_per_intr); 141 /* Enable PIT & FIT(2^17c = 0.655ms) interrupts and auto-reload */ 142 mtspr(SPR_TCR, TCR_PIE | TCR_ARE | TCR_FIE | TCR_PERIOD); 143 } 144 145 void 146 calc_delayconst(void) 147 { 148 unsigned int processor_freq; 149 150 if (board_info_get("processor-frequency", 151 &processor_freq, sizeof(processor_freq)) == -1) 152 panic("no processor-frequency"); 153 154 ticks_per_sec = processor_freq; 155 ns_per_tick = 1000000000 / ticks_per_sec; 156 } 157 158 /* 159 * Fill in *tvp with current time with microsecond resolution. 160 */ 161 void 162 microtime(struct timeval *tvp) 163 { 164 u_long tb; 165 u_long ticks; 166 int msr; 167 168 asm volatile ("mfmsr %0; wrteei 0" : "=r"(msr) :); 169 tb = mftbl(); 170 ticks = (tb - lasttb) * ns_per_tick; 171 *tvp = time; 172 asm volatile ("mtmsr %0" :: "r"(msr)); 173 ticks /= 1000; 174 tvp->tv_usec += ticks; 175 while (tvp->tv_usec >= 1000000) { 176 tvp->tv_usec -= 1000000; 177 tvp->tv_sec++; 178 } 179 } 180 181 /* 182 * Wait for about n microseconds (at least!). 183 */ 184 void 185 delay(unsigned int n) 186 { 187 u_quad_t tb; 188 u_long tbh, tbl, scratch; 189 190 tb = mftb(); 191 /* use 1000ULL to force 64 bit math to avoid 32 bit overflows */ 192 tb += (n * 1000ULL + ns_per_tick - 1) / ns_per_tick; 193 tbh = tb >> 32; 194 tbl = tb; 195 asm volatile ( 196 #ifdef PPC_IBM403 197 "1: mftbhi %0 \n" 198 #else 199 "1: mftbu %0 \n" 200 #endif 201 " cmplw %0,%1 \n" 202 " blt 1b \n" 203 " bgt 2f \n" 204 #ifdef PPC_IBM403 205 " mftblo %0 \n" 206 #else 207 " mftb %0 \n" 208 #endif 209 " cmplw %0,%2 \n" 210 " blt 1b \n" 211 "2: \n" 212 : "=&r"(scratch) : "r"(tbh), "r"(tbl) : "cr0"); 213 } 214 215 /* 216 * Nothing to do. 217 */ 218 void 219 setstatclockrate(int arg) 220 { 221 222 /* Do nothing */ 223 } 224