1 /* $NetBSD: timer.c,v 1.9 2006/09/24 02:20:48 tsutsui Exp $ */ 2 /* NetBSD: clock.c,v 1.31 2001/05/27 13:53:24 sommerfeld Exp */ 3 4 /* 5 * Copyright (c) 1992, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department and Ralph Campbell. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: Utah Hdr: clock.c 1.18 91/01/21 37 * 38 * @(#)clock.c 8.1 (Berkeley) 6/10/93 39 */ 40 /* 41 * Copyright (c) 1988 University of Utah. 42 * 43 * This code is derived from software contributed to Berkeley by 44 * the Systems Programming Group of the University of Utah Computer 45 * Science Department and Ralph Campbell. 46 * 47 * Redistribution and use in source and binary forms, with or without 48 * modification, are permitted provided that the following conditions 49 * are met: 50 * 1. Redistributions of source code must retain the above copyright 51 * notice, this list of conditions and the following disclaimer. 52 * 2. Redistributions in binary form must reproduce the above copyright 53 * notice, this list of conditions and the following disclaimer in the 54 * documentation and/or other materials provided with the distribution. 55 * 3. All advertising materials mentioning features or use of this software 56 * must display the following acknowledgement: 57 * This product includes software developed by the University of 58 * California, Berkeley and its contributors. 59 * 4. Neither the name of the University nor the names of its contributors 60 * may be used to endorse or promote products derived from this software 61 * without specific prior written permission. 62 * 63 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 64 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 65 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 66 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 67 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 68 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 69 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 70 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 71 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 72 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 73 * SUCH DAMAGE. 74 * 75 * from: Utah Hdr: clock.c 1.18 91/01/21 76 * 77 * @(#)clock.c 8.1 (Berkeley) 6/10/93 78 */ 79 80 #include <sys/cdefs.h> /* RCS ID & Copyright macro defns */ 81 82 __KERNEL_RCSID(0, "$NetBSD: timer.c,v 1.9 2006/09/24 02:20:48 tsutsui Exp $"); 83 84 #include <sys/param.h> 85 #include <sys/kernel.h> 86 #include <sys/systm.h> 87 88 #include <mips/locore.h> 89 #include <mips/mips3_clock.h> 90 91 #include <arc/arc/timervar.h> 92 93 struct device *timerdev; 94 const struct timerfns *timerfns; 95 int timerinitted; 96 uint32_t last_cp0_count; 97 98 #ifdef ENABLE_INT5_STATCLOCK 99 /* 100 * Statistics clock variance, in usec. Variance must be a 101 * power of two. Since this gives us an even number, not an odd number, 102 * we discard one case and compensate. That is, a variance of 1024 would 103 * give us offsets in [0..1023]. Instead, we take offsets in [1..1023]. 104 * This is symmetric about the point 512, or statvar/2, and thus averages 105 * to that value (assuming uniform random numbers). 106 */ 107 static const uint32_t statvar = 1024; 108 static uint32_t statint; /* number of clock ticks for stathz */ 109 static uint32_t statmin; /* minimum stat clock count in ticks */ 110 static uint32_t statprev;/* last value of we set statclock to */ 111 static u_int statcountperusec; /* number of ticks per usec at current stathz */ 112 #endif 113 114 void 115 timerattach(struct device *dev, const struct timerfns *fns) 116 { 117 118 /* 119 * Just bookkeeping. 120 */ 121 122 if (timerfns != NULL) 123 panic("timerattach: multiple timers"); 124 timerdev = dev; 125 timerfns = fns; 126 } 127 128 /* 129 * Machine-dependent clock routines. 130 */ 131 132 /* 133 * Start the real-time and statistics clocks. Leave stathz 0 since there 134 * are no other timers available. 135 */ 136 void 137 cpu_initclocks(void) 138 { 139 140 #ifdef ENABLE_INT5_STATCLOCK 141 if (stathz == 0) 142 stathz = hz; 143 144 if (profhz == 0) 145 profhz = hz * 5; 146 147 setstatclockrate(stathz); 148 #endif 149 150 if (timerfns == NULL) 151 panic("cpu_initclocks: no timer attached"); 152 153 /* 154 * Get the clock started. 155 */ 156 (*timerfns->tf_init)(timerdev); 157 158 /* init timecounter */ 159 mips3_init_tc(); 160 161 #ifdef ENABLE_INT5_STATCLOCK 162 /* enable interrupts including CPU INT 5 */ 163 _splnone(); 164 #endif 165 } 166 167 /* 168 * We assume newhz is either stathz or profhz, and that neither will 169 * change after being set up above. Could recalculate intervals here 170 * but that would be a drag. 171 */ 172 void 173 setstatclockrate(int newhz) 174 { 175 #ifdef ENABLE_INT5_STATCLOCK 176 uint32_t countpersecond, statvarticks; 177 178 statprev = mips3_cp0_count_read(); 179 180 statint = ((curcpu()->ci_cpu_freq + newhz / 2) / newhz) / 2; 181 182 /* Get the total ticks a second */ 183 countpersecond = statint * newhz; 184 185 /* now work out how many ticks per usec */ 186 statcountperusec = countpersecond / 1000000; 187 188 /* calculate a variance range of statvar */ 189 statvarticks = statcountperusec * statvar; 190 191 /* minimum is statint - 50% of variant */ 192 statmin = statint - (statvarticks / 2); 193 194 mips3_cp0_compare_write(statprev + statint); 195 #endif 196 } 197 198 #ifdef ENABLE_INT5_STATCLOCK 199 void 200 statclockintr(struct clockframe *cfp) 201 { 202 uint32_t curcount, statnext, delta, r; 203 int lost; 204 205 lost = 0; 206 207 do { 208 r = (uint32_t)random() & (statvar - 1); 209 } while (r == 0); 210 statnext = statprev + statmin + (r * statcountperusec); 211 212 mips3_cp0_compare_write(statnext); 213 curcount = mips3_cp0_count_read(); 214 delta = statnext - curcount; 215 216 while (__predict_false((int32_t)delta < 0)) { 217 lost++; 218 delta += statint; 219 } 220 if (__predict_false(lost > 0)) { 221 statnext = curcount + delta; 222 mips3_cp0_compare_write(statnext); 223 for (; lost > 0; lost--) 224 statclock(cfp); 225 } 226 statclock(cfp); 227 228 statprev = statnext; 229 } 230 #endif 231