1 /* $NetBSD: clock.c,v 1.22 2010/02/25 23:31:47 matt 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 1.22 2010/02/25 23:31:47 matt 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 #include <powerpc/ibm4xx/spr.h> 51 52 /* 53 * Initially we assume a processor with a bus frequency of 12.5 MHz. 54 */ 55 static u_long ticks_per_sec; 56 static u_long ns_per_tick; 57 static long ticks_per_intr; 58 static volatile u_long lasttb, lasttb2; 59 static u_long ticksmissed; 60 static volatile int tickspending; 61 62 static void init_ppc4xx_tc(void); 63 static u_int get_ppc4xx_timecount(struct timecounter *); 64 65 static struct timecounter ppc4xx_timecounter = { 66 get_ppc4xx_timecount, /* get_timecount */ 67 0, /* no poll_pps */ 68 ~0u, /* counter_mask */ 69 0, /* frequency */ 70 "ppc_timebase", /* name */ 71 100, /* quality */ 72 NULL, /* tc_priv */ 73 NULL /* tc_next */ 74 }; 75 76 void decr_intr(struct clockframe *); /* called from trap_subr.S */ 77 void stat_intr(struct clockframe *); /* called from trap_subr.S */ 78 79 #ifdef FAST_STAT_CLOCK 80 /* Stat clock runs at ~ 1.5 kHz */ 81 #define PERIOD_POWER 17 82 #define TCR_PERIOD TCR_FP_2_17 83 #else 84 /* Stat clock runs at ~ 95Hz */ 85 #define PERIOD_POWER 21 86 #define TCR_PERIOD TCR_FP_2_21 87 #endif 88 89 90 void 91 stat_intr(struct clockframe *frame) 92 { 93 94 mtspr(SPR_TSR, TSR_FIS); /* Clear TSR[FIS] */ 95 uvmexp.intrs++; 96 curcpu()->ci_ev_statclock.ev_count++; 97 98 /* Nobody can interrupt us, but see if we're allowed to run. */ 99 if (! (curcpu()->ci_cpl & mask_statclock)) 100 statclock(frame); 101 } 102 103 void 104 decr_intr(struct clockframe *frame) 105 { 106 int pri; 107 long tbtick, xticks; 108 int nticks; 109 110 /* 111 * Check whether we are initialized. 112 */ 113 if (!ticks_per_intr) 114 return; 115 116 tbtick = mftbl(); 117 mtspr(SPR_TSR, TSR_PIS); /* Clear TSR[PIS] */ 118 119 xticks = tbtick - lasttb2; /* Number of TLB cycles since last exception */ 120 for (nticks = 0; xticks > ticks_per_intr; nticks++) 121 xticks -= ticks_per_intr; 122 lasttb2 = tbtick - xticks; 123 124 uvmexp.intrs++; 125 curcpu()->ci_ev_clock.ev_count++; 126 pri = splclock(); 127 if (pri & mask_clock) { 128 tickspending += nticks; 129 ticksmissed += nticks; 130 } else { 131 nticks += tickspending; 132 tickspending = 0; 133 134 /* 135 * lasttb is used during microtime. Set it to the virtual 136 * start of this tick interval. 137 */ 138 lasttb = lasttb2; 139 140 /* 141 * Reenable interrupts 142 */ 143 __asm volatile ("wrteei 1"); 144 145 /* 146 * Do standard timer interrupt stuff. 147 * Do softclock stuff only on the last iteration. 148 */ 149 frame->pri = pri | mask_clock; 150 while (--nticks > 0) 151 hardclock(frame); 152 frame->pri = pri; 153 hardclock(frame); 154 } 155 splx(pri); 156 } 157 158 void 159 cpu_initclocks(void) 160 { 161 /* Initialized in powerpc/ibm4xx/cpu.c */ 162 evcnt_attach_static(&curcpu()->ci_ev_clock); 163 evcnt_attach_static(&curcpu()->ci_ev_statclock); 164 165 ticks_per_intr = ticks_per_sec / hz; 166 stathz = profhz = ticks_per_sec / (1 << PERIOD_POWER); 167 168 printf("Setting PIT to %ld/%d = %ld\n", ticks_per_sec, hz, 169 ticks_per_intr); 170 171 lasttb2 = lasttb = mftbl(); 172 mtspr(SPR_PIT, ticks_per_intr); 173 174 /* Enable PIT & FIT(2^17c = 0.655ms) interrupts and auto-reload */ 175 mtspr(SPR_TCR, TCR_PIE | TCR_ARE | TCR_FIE | TCR_PERIOD); 176 177 init_ppc4xx_tc(); 178 } 179 180 void 181 calc_delayconst(void) 182 { 183 prop_number_t freq; 184 185 freq = prop_dictionary_get(board_properties, "processor-frequency"); 186 KASSERT(freq != NULL); 187 188 ticks_per_sec = (u_long) prop_number_integer_value(freq); 189 ns_per_tick = 1000000000 / ticks_per_sec; 190 } 191 192 static u_int 193 get_ppc4xx_timecount(struct timecounter *tc) 194 { 195 u_long tb; 196 int msr; 197 198 __asm volatile ("mfmsr %0; wrteei 0" : "=r"(msr) :); 199 tb = mftbl(); 200 __asm volatile ("mtmsr %0" :: "r"(msr)); 201 202 return tb; 203 } 204 205 /* 206 * Wait for about n microseconds (at least!). 207 */ 208 void 209 delay(unsigned int n) 210 { 211 u_quad_t tb; 212 u_long tbh, tbl, scratch; 213 214 tb = mftb(); 215 /* use 1000ULL to force 64 bit math to avoid 32 bit overflows */ 216 tb += (n * 1000ULL + ns_per_tick - 1) / ns_per_tick; 217 tbh = tb >> 32; 218 tbl = tb; 219 __asm volatile ( 220 #ifdef PPC_IBM403 221 "1: mftbhi %0 \n" 222 #else 223 "1: mftbu %0 \n" 224 #endif 225 " cmplw %0,%1 \n" 226 " blt 1b \n" 227 " bgt 2f \n" 228 #ifdef PPC_IBM403 229 " mftblo %0 \n" 230 #else 231 " mftb %0 \n" 232 #endif 233 " cmplw %0,%2 \n" 234 " blt 1b \n" 235 "2: \n" 236 : "=&r"(scratch) : "r"(tbh), "r"(tbl) : "cr0"); 237 } 238 239 /* 240 * Nothing to do. 241 */ 242 void 243 setstatclockrate(int arg) 244 { 245 246 /* Do nothing */ 247 } 248 249 static void 250 init_ppc4xx_tc(void) 251 { 252 /* from machdep initialization */ 253 ppc4xx_timecounter.tc_frequency = ticks_per_sec; 254 tc_init(&ppc4xx_timecounter); 255 } 256