clock.c revision 247463
1/*- 2 * Copyright (C) 1995, 1996 Wolfgang Solfrank. 3 * Copyright (C) 1995, 1996 TooLs GmbH. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by TooLs GmbH. 17 * 4. The name of TooLs GmbH may not be used to endorse or promote products 18 * derived from this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 26 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 28 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 29 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 * 31 * $NetBSD: clock.c,v 1.9 2000/01/19 02:52:19 msaitoh Exp $ 32 */ 33/* 34 * Copyright (C) 2001 Benno Rice. 35 * All rights reserved. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 46 * THIS SOFTWARE IS PROVIDED BY Benno Rice ``AS IS'' AND ANY EXPRESS OR 47 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 48 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 49 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 50 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 51 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 52 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 53 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 54 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 55 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 56 */ 57 58#include <sys/cdefs.h> 59__FBSDID("$FreeBSD: head/sys/powerpc/aim/clock.c 247463 2013-02-28 13:46:03Z mav $"); 60 61#include <sys/param.h> 62#include <sys/systm.h> 63#include <sys/kernel.h> 64#include <sys/bus.h> 65#include <sys/interrupt.h> 66#include <sys/pcpu.h> 67#include <sys/sysctl.h> 68#include <sys/timeet.h> 69#include <sys/timetc.h> 70 71#include <dev/ofw/openfirm.h> 72 73#include <machine/clock.h> 74#include <machine/cpu.h> 75#include <machine/intr_machdep.h> 76#include <machine/md_var.h> 77#include <machine/smp.h> 78 79/* 80 * Initially we assume a processor with a bus frequency of 12.5 MHz. 81 */ 82static int initialized = 0; 83static u_long ns_per_tick = 80; 84static u_long ticks_per_sec = 12500000; 85static u_long *decr_counts[MAXCPU]; 86 87static int decr_et_start(struct eventtimer *et, 88 sbintime_t first, sbintime_t period); 89static int decr_et_stop(struct eventtimer *et); 90static timecounter_get_t decr_get_timecount; 91 92struct decr_state { 93 int mode; /* 0 - off, 1 - periodic, 2 - one-shot. */ 94 int32_t div; /* Periodic divisor. */ 95}; 96static DPCPU_DEFINE(struct decr_state, decr_state); 97 98static struct eventtimer decr_et; 99static struct timecounter decr_tc = { 100 decr_get_timecount, /* get_timecount */ 101 0, /* no poll_pps */ 102 ~0u, /* counter_mask */ 103 0, /* frequency */ 104 "timebase" /* name */ 105}; 106 107/* 108 * Decrementer interrupt handler. 109 */ 110void 111decr_intr(struct trapframe *frame) 112{ 113 struct decr_state *s = DPCPU_PTR(decr_state); 114 int nticks = 0; 115 int32_t val; 116 117 if (!initialized) 118 return; 119 120 (*decr_counts[curcpu])++; 121 122 if (s->mode == 1) { 123 /* 124 * Based on the actual time delay since the last decrementer 125 * reload, we arrange for earlier interrupt next time. 126 */ 127 __asm ("mfdec %0" : "=r"(val)); 128 while (val < 0) { 129 val += s->div; 130 nticks++; 131 } 132 mtdec(val); 133 } else if (s->mode == 2) { 134 nticks = 1; 135 decr_et_stop(NULL); 136 } 137 138 while (nticks-- > 0) { 139 if (decr_et.et_active) 140 decr_et.et_event_cb(&decr_et, decr_et.et_arg); 141 } 142} 143 144/* 145 * BSP early initialization. 146 */ 147void 148decr_init(void) 149{ 150 struct cpuref cpu; 151 char buf[32]; 152 153 /* 154 * Check the BSP's timebase frequency. Sometimes we can't find the BSP, so fall 155 * back to the first CPU in this case. 156 */ 157 if (platform_smp_get_bsp(&cpu) != 0) 158 platform_smp_first_cpu(&cpu); 159 ticks_per_sec = platform_timebase_freq(&cpu); 160 ns_per_tick = 1000000000 / ticks_per_sec; 161 162 set_cputicker(mftb, ticks_per_sec, 0); 163 snprintf(buf, sizeof(buf), "cpu%d:decrementer", curcpu); 164 intrcnt_add(buf, &decr_counts[curcpu]); 165 decr_et_stop(NULL); 166 initialized = 1; 167} 168 169#ifdef SMP 170/* 171 * AP early initialization. 172 */ 173void 174decr_ap_init(void) 175{ 176 char buf[32]; 177 178 snprintf(buf, sizeof(buf), "cpu%d:decrementer", curcpu); 179 intrcnt_add(buf, &decr_counts[curcpu]); 180 decr_et_stop(NULL); 181} 182#endif 183 184/* 185 * Final initialization. 186 */ 187void 188decr_tc_init(void) 189{ 190 191 decr_tc.tc_frequency = ticks_per_sec; 192 tc_init(&decr_tc); 193 decr_et.et_name = "decrementer"; 194 decr_et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT | 195 ET_FLAGS_PERCPU; 196 decr_et.et_quality = 1000; 197 decr_et.et_frequency = ticks_per_sec; 198 decr_et.et_min_period = (0x00000002LLU << 32) / ticks_per_sec; 199 decr_et.et_max_period = (0x7fffffffLLU << 32) / ticks_per_sec; 200 decr_et.et_start = decr_et_start; 201 decr_et.et_stop = decr_et_stop; 202 decr_et.et_priv = NULL; 203 et_register(&decr_et); 204} 205 206/* 207 * Event timer start method. 208 */ 209static int 210decr_et_start(struct eventtimer *et, 211 sbintime_t first, sbintime_t period) 212{ 213 struct decr_state *s = DPCPU_PTR(decr_state); 214 uint32_t fdiv; 215 216 if (period != 0) { 217 s->mode = 1; 218 s->div = (decr_et.et_frequency * period) >> 32; 219 } else { 220 s->mode = 2; 221 s->div = 0; 222 } 223 if (first != 0) { 224 fdiv = (decr_et.et_frequency * first) >> 32; 225 } else 226 fdiv = s->div; 227 228 mtdec(fdiv); 229 return (0); 230} 231 232/* 233 * Event timer stop method. 234 */ 235static int 236decr_et_stop(struct eventtimer *et) 237{ 238 struct decr_state *s = DPCPU_PTR(decr_state); 239 240 s->mode = 0; 241 s->div = 0x7fffffff; 242 mtdec(s->div); 243 return (0); 244} 245 246/* 247 * Timecounter get method. 248 */ 249static unsigned 250decr_get_timecount(struct timecounter *tc) 251{ 252 register_t tb; 253 254 __asm __volatile("mftb %0" : "=r"(tb)); 255 return (tb); 256} 257 258/* 259 * Wait for about n microseconds (at least!). 260 */ 261void 262DELAY(int n) 263{ 264 u_quad_t tb, ttb; 265 266 tb = mftb(); 267 ttb = tb + (n * 1000 + ns_per_tick - 1) / ns_per_tick; 268 while (tb < ttb) 269 tb = mftb(); 270} 271 272