1 /* $NetBSD: clock.c,v 1.21 2008/01/09 06:50:36 simonb 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 1.21 2008/01/09 06:50:36 simonb Exp $"); 37 38 #include <sys/param.h> 39 #include <sys/kernel.h> 40 #include <sys/systm.h> 41 #include <sys/timetc.h> 42 43 #include <uvm/uvm_extern.h> 44 45 #include <prop/proplib.h> 46 47 #include <machine/cpu.h> 48 49 #include <powerpc/spr.h> 50 51 /* 52 * Initially we assume a processor with a bus frequency of 12.5 MHz. 53 */ 54 static u_long ticks_per_sec; 55 static u_long ns_per_tick; 56 static long ticks_per_intr; 57 static volatile u_long lasttb, lasttb2; 58 static u_long ticksmissed; 59 static volatile int tickspending; 60 61 static void init_ppc4xx_tc(void); 62 static u_int get_ppc4xx_timecount(struct timecounter *); 63 64 static struct timecounter ppc4xx_timecounter = { 65 get_ppc4xx_timecount, /* get_timecount */ 66 0, /* no poll_pps */ 67 ~0u, /* counter_mask */ 68 0, /* frequency */ 69 "ppc_timebase", /* name */ 70 100, /* quality */ 71 NULL, /* tc_priv */ 72 NULL /* tc_next */ 73 }; 74 75 void decr_intr(struct clockframe *); /* called from trap_subr.S */ 76 void stat_intr(struct clockframe *); /* called from trap_subr.S */ 77 78 #ifdef FAST_STAT_CLOCK 79 /* Stat clock runs at ~ 1.5 kHz */ 80 #define PERIOD_POWER 17 81 #define TCR_PERIOD TCR_FP_2_17 82 #else 83 /* Stat clock runs at ~ 95Hz */ 84 #define PERIOD_POWER 21 85 #define TCR_PERIOD TCR_FP_2_21 86 #endif 87 88 89 void 90 stat_intr(struct clockframe *frame) 91 { 92 93 mtspr(SPR_TSR, TSR_FIS); /* Clear TSR[FIS] */ 94 uvmexp.intrs++; 95 curcpu()->ci_ev_statclock.ev_count++; 96 97 /* Nobody can interrupt us, but see if we're allowed to run. */ 98 if (! (curcpu()->ci_cpl & mask_statclock)) 99 statclock(frame); 100 } 101 102 void 103 decr_intr(struct clockframe *frame) 104 { 105 int pri; 106 long tbtick, xticks; 107 int nticks; 108 109 /* 110 * Check whether we are initialized. 111 */ 112 if (!ticks_per_intr) 113 return; 114 115 tbtick = mftbl(); 116 mtspr(SPR_TSR, TSR_PIS); /* Clear TSR[PIS] */ 117 118 xticks = tbtick - lasttb2; /* Number of TLB cycles since last exception */ 119 for (nticks = 0; xticks > ticks_per_intr; nticks++) 120 xticks -= ticks_per_intr; 121 lasttb2 = tbtick - xticks; 122 123 uvmexp.intrs++; 124 curcpu()->ci_ev_clock.ev_count++; 125 pri = splclock(); 126 if (pri & mask_clock) { 127 tickspending += nticks; 128 ticksmissed += nticks; 129 } else { 130 nticks += tickspending; 131 tickspending = 0; 132 133 /* 134 * lasttb is used during microtime. Set it to the virtual 135 * start of this tick interval. 136 */ 137 lasttb = lasttb2; 138 139 /* 140 * Reenable interrupts 141 */ 142 __asm volatile ("wrteei 1"); 143 144 /* 145 * Do standard timer interrupt stuff. 146 * Do softclock stuff only on the last iteration. 147 */ 148 frame->pri = pri | mask_clock; 149 while (--nticks > 0) 150 hardclock(frame); 151 frame->pri = pri; 152 hardclock(frame); 153 } 154 splx(pri); 155 } 156 157 void 158 cpu_initclocks(void) 159 { 160 /* Initialized in powerpc/ibm4xx/cpu.c */ 161 evcnt_attach_static(&curcpu()->ci_ev_clock); 162 evcnt_attach_static(&curcpu()->ci_ev_statclock); 163 164 ticks_per_intr = ticks_per_sec / hz; 165 stathz = profhz = ticks_per_sec / (1 << PERIOD_POWER); 166 167 printf("Setting PIT to %ld/%d = %ld\n", ticks_per_sec, hz, 168 ticks_per_intr); 169 170 lasttb2 = lasttb = mftbl(); 171 mtspr(SPR_PIT, ticks_per_intr); 172 173 /* Enable PIT & FIT(2^17c = 0.655ms) interrupts and auto-reload */ 174 mtspr(SPR_TCR, TCR_PIE | TCR_ARE | TCR_FIE | TCR_PERIOD); 175 176 init_ppc4xx_tc(); 177 } 178 179 void 180 calc_delayconst(void) 181 { 182 prop_number_t freq; 183 184 freq = prop_dictionary_get(board_properties, "processor-frequency"); 185 KASSERT(freq != NULL); 186 187 ticks_per_sec = (u_long) prop_number_integer_value(freq); 188 ns_per_tick = 1000000000 / ticks_per_sec; 189 } 190 191 static u_int 192 get_ppc4xx_timecount(struct timecounter *tc) 193 { 194 u_long tb; 195 int msr; 196 197 __asm volatile ("mfmsr %0; wrteei 0" : "=r"(msr) :); 198 tb = mftbl(); 199 __asm volatile ("mtmsr %0" :: "r"(msr)); 200 201 return tb; 202 } 203 204 /* 205 * Wait for about n microseconds (at least!). 206 */ 207 void 208 delay(unsigned int n) 209 { 210 u_quad_t tb; 211 u_long tbh, tbl, scratch; 212 213 tb = mftb(); 214 /* use 1000ULL to force 64 bit math to avoid 32 bit overflows */ 215 tb += (n * 1000ULL + ns_per_tick - 1) / ns_per_tick; 216 tbh = tb >> 32; 217 tbl = tb; 218 __asm volatile ( 219 #ifdef PPC_IBM403 220 "1: mftbhi %0 \n" 221 #else 222 "1: mftbu %0 \n" 223 #endif 224 " cmplw %0,%1 \n" 225 " blt 1b \n" 226 " bgt 2f \n" 227 #ifdef PPC_IBM403 228 " mftblo %0 \n" 229 #else 230 " mftb %0 \n" 231 #endif 232 " cmplw %0,%2 \n" 233 " blt 1b \n" 234 "2: \n" 235 : "=&r"(scratch) : "r"(tbh), "r"(tbl) : "cr0"); 236 } 237 238 /* 239 * Nothing to do. 240 */ 241 void 242 setstatclockrate(int arg) 243 { 244 245 /* Do nothing */ 246 } 247 248 static void 249 init_ppc4xx_tc(void) 250 { 251 /* from machdep initialization */ 252 ppc4xx_timecounter.tc_frequency = ticks_per_sec; 253 tc_init(&ppc4xx_timecounter); 254 } 255