clock.c revision 1.5
1 /* $NetBSD: clock.c,v 1.5 2002/08/06 06:14:36 chs 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/param.h> 36 #include <sys/kernel.h> 37 #include <sys/systm.h> 38 #include <sys/properties.h> 39 40 #include <machine/walnut.h> 41 #include <machine/dcr.h> 42 43 #include <powerpc/spr.h> 44 45 /* 46 * Initially we assume a processor with a bus frequency of 12.5 MHz. 47 */ 48 static u_long ticks_per_sec; 49 static u_long ns_per_tick; 50 static long ticks_per_intr; 51 static volatile u_long lasttb; 52 static u_long ticksmissed; 53 static volatile int tickspending; 54 55 void decr_intr(struct clockframe *); /* called from trap_subr.S */ 56 void stat_intr(struct clockframe *); /* called from trap_subr.S */ 57 58 #ifdef FAST_STAT_CLOCK 59 /* Stat clock runs at ~ 1.5KHz */ 60 #define PERIOD_POWER 17 61 #define TCR_PERIOD TCR_FP_2_17 62 #else 63 /* Stat clock runs at ~ 95Hz */ 64 #define PERIOD_POWER 21 65 #define TCR_PERIOD TCR_FP_2_21 66 #endif 67 68 69 void 70 stat_intr(struct clockframe *frame) 71 { 72 extern u_long intrcnt[]; 73 74 mtspr(SPR_TSR, TSR_FIS); /* Clear TSR[FIS] */ 75 intrcnt[CNT_STATCLOCK]++; 76 statclock(frame); 77 } 78 79 void 80 decr_intr(struct clockframe *frame) 81 { 82 int pri; 83 long tick, xticks; 84 int nticks; 85 extern u_long intrcnt[]; 86 /* 87 * Check whether we are initialized. 88 */ 89 if (!ticks_per_intr) 90 return; 91 92 asm volatile("mftb %0":"=r"(tick):); 93 mtspr(SPR_TSR, TSR_PIS); /* Clear TSR[PIS] */ 94 /* 95 * lasttb is used during microtime. Set it to the virtual 96 * start of this tick interval. 97 */ 98 xticks = tick - lasttb; /* Number of TLB cycles since last exception */ 99 for (nticks = 0; xticks > ticks_per_intr; nticks++) 100 xticks -= ticks_per_intr; 101 lasttb = tick - xticks; 102 103 intrcnt[CNT_CLOCK]++; 104 pri = splclock(); 105 if (pri & SPL_CLOCK) { 106 tickspending += nticks; 107 ticksmissed+= nticks; 108 } else { 109 nticks += tickspending; 110 tickspending = 0; 111 112 /* 113 * Reenable interrupts 114 */ 115 asm volatile ("wrteei 1"); 116 117 /* 118 * Do standard timer interrupt stuff. 119 * Do softclock stuff only on the last iteration. 120 */ 121 frame->pri = pri | SINT_CLOCK; 122 while (--nticks > 0) 123 hardclock(frame); 124 frame->pri = pri; 125 hardclock(frame); 126 } 127 splx(pri); 128 } 129 130 void 131 cpu_initclocks(void) 132 { 133 134 ticks_per_intr = ticks_per_sec / hz; 135 stathz = profhz = ticks_per_sec / (1 << PERIOD_POWER); 136 printf("Setting PIT to %ld/%d = %ld\n", ticks_per_sec, hz, ticks_per_intr); 137 asm volatile ("mftb %0" : "=r"(lasttb)); 138 mtspr(SPR_PIT, ticks_per_intr); 139 /* Enable PIT & FIT(2^17c = 0.655ms) interrupts and auto-reload */ 140 mtspr(SPR_TCR, TCR_PIE | TCR_ARE | TCR_FIE | TCR_PERIOD); 141 } 142 143 void 144 calc_delayconst(void) 145 { 146 unsigned int processor_freq; 147 148 if (board_info_get("processor-frequency", 149 &processor_freq, sizeof(processor_freq)) == -1) 150 panic("no processor-frequency"); 151 152 ticks_per_sec = processor_freq; 153 ns_per_tick = 1000000000 / ticks_per_sec; 154 155 /* Make sure that timers run at CPU frequency */ 156 mtdcr(DCR_CPC0_CR1, mfdcr(DCR_CPC0_CR1) & ~CPC0_CR1_CETE); 157 } 158 159 /* 160 * Fill in *tvp with current time with microsecond resolution. 161 */ 162 void 163 microtime(struct timeval *tvp) 164 { 165 u_long tb; 166 u_long ticks; 167 int msr; 168 169 asm volatile ("mfmsr %0; wrteei 0" : "=r"(msr) :); 170 asm ("mftb %0" : "=r"(tb)); 171 ticks = (tb - lasttb) * ns_per_tick; 172 *tvp = time; 173 asm volatile ("mtmsr %0" :: "r"(msr)); 174 ticks /= 1000; 175 tvp->tv_usec += ticks; 176 while (tvp->tv_usec >= 1000000) { 177 tvp->tv_usec -= 1000000; 178 tvp->tv_sec++; 179 } 180 } 181 182 /* 183 * Wait for about n microseconds (at least!). 184 */ 185 void 186 delay(unsigned int n) 187 { 188 u_quad_t tb; 189 u_long tbh, tbl, scratch; 190 191 tb = mftb(); 192 /* use 1000ULL to force 64 bit math to avoid 32 bit overflows */ 193 tb += (n * 1000ULL + ns_per_tick - 1) / ns_per_tick; 194 tbh = tb >> 32; 195 tbl = tb; 196 asm volatile ("1: mftbu %0; cmplw %0,%1; blt 1b; bgt 2f;" 197 "mftb %0; cmplw %0,%2; blt 1b; 2:" 198 : "=r"(scratch) : "r"(tbh), "r"(tbl)); 199 } 200 201 /* 202 * Nothing to do. 203 */ 204 void 205 setstatclockrate(int arg) 206 { 207 208 /* Do nothing */ 209 } 210
Indexes created Wed Oct 01 13:09:50 GMT 2025