1 /* 2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * $DragonFly: src/sys/kern/kern_systimer.c,v 1.10 2007/04/30 07:18:54 dillon Exp $ 35 */ 36 37 /* 38 * WARNING! THE SYSTIMER MODULE DOES NOT OPERATE OR DISPATCH WITH THE 39 * MP LOCK HELD. ALL CODE USING THIS MODULE MUST BE MP-SAFE. 40 * 41 * This code implements a fine-grained per-cpu system timer which is 42 * ultimately based on a hardware timer. The hardware timer abstraction 43 * is sufficiently disconnected from this code to support both per-cpu 44 * hardware timers or a single system-wide hardware timer. 45 * 46 * WARNING! During early boot if a new system timer is selected, existing 47 * timeouts will not be effected and will thus occur slower or faster. 48 * periodic timers will be adjusted at the next periodic load. 49 * 50 * Notes on machine-dependant code (in arch/arch/systimer.c) 51 * 52 * cputimer_intr_reload() Reload the one-shot (per-cpu basis) 53 */ 54 55 #include <sys/param.h> 56 #include <sys/kernel.h> 57 #include <sys/systm.h> 58 #include <sys/thread.h> 59 #include <sys/globaldata.h> 60 #include <sys/systimer.h> 61 #include <sys/thread2.h> 62 63 /* 64 * Execute ready systimers. Called directly from the platform-specific 65 * one-shot timer clock interrupt (e.g. clkintr()) or via an IPI. May 66 * be called simultaniously on multiple cpus and always operations on 67 * the current cpu's queue. Systimer functions are responsible for calling 68 * hardclock, statclock, and other finely-timed routines. 69 */ 70 void 71 systimer_intr(sysclock_t *timep, int dummy, struct intrframe *frame) 72 { 73 globaldata_t gd = mycpu; 74 sysclock_t time = *timep; 75 systimer_t info; 76 77 if (gd->gd_syst_nest) 78 return; 79 80 crit_enter(); 81 ++gd->gd_syst_nest; 82 while ((info = TAILQ_FIRST(&gd->gd_systimerq)) != NULL) { 83 /* 84 * If we haven't reached the requested time, tell the cputimer 85 * how much is left and break out. 86 */ 87 if ((int)(info->time - time) > 0) { 88 cputimer_intr_reload(info->time - time); 89 break; 90 } 91 92 /* 93 * Dequeue and execute 94 */ 95 info->flags &= ~SYSTF_ONQUEUE; 96 TAILQ_REMOVE(info->queue, info, node); 97 crit_exit(); 98 info->func(info, frame); 99 crit_enter(); 100 101 /* 102 * Reinstall if periodic. If this is a non-queued periodic 103 * interrupt do not allow multiple events to build up (used 104 * for things like the callout timer to prevent premature timeouts 105 * due to long interrupt disablements, BIOS 8254 glitching, and so 106 * forth). However, we still want to keep things synchronized between 107 * cpus for efficient handling of the timer interrupt so jump in 108 * multiples of the periodic rate. 109 */ 110 if (info->periodic) { 111 if (info->which != sys_cputimer) { 112 info->periodic = sys_cputimer->fromhz(info->freq); 113 info->which = sys_cputimer; 114 } 115 info->time += info->periodic; 116 if ((info->flags & SYSTF_NONQUEUED) && 117 (int)(info->time - time) <= 0 118 ) { 119 info->time += ((time - info->time + info->periodic - 1) / 120 info->periodic) * info->periodic; 121 } 122 systimer_add(info); 123 } 124 } 125 --gd->gd_syst_nest; 126 crit_exit(); 127 } 128 129 void 130 systimer_add(systimer_t info) 131 { 132 struct globaldata *gd = mycpu; 133 134 KKASSERT((info->flags & (SYSTF_ONQUEUE|SYSTF_IPIRUNNING)) == 0); 135 crit_enter(); 136 if (info->gd == gd) { 137 systimer_t scan1; 138 systimer_t scan2; 139 scan1 = TAILQ_FIRST(&gd->gd_systimerq); 140 if (scan1 == NULL || (int)(scan1->time - info->time) > 0) { 141 cputimer_intr_reload(info->time - sys_cputimer->count()); 142 TAILQ_INSERT_HEAD(&gd->gd_systimerq, info, node); 143 } else { 144 scan2 = TAILQ_LAST(&gd->gd_systimerq, systimerq); 145 for (;;) { 146 if (scan1 == NULL) { 147 TAILQ_INSERT_TAIL(&gd->gd_systimerq, info, node); 148 break; 149 } 150 if ((int)(scan1->time - info->time) > 0) { 151 TAILQ_INSERT_BEFORE(scan1, info, node); 152 break; 153 } 154 if ((int)(scan2->time - info->time) <= 0) { 155 TAILQ_INSERT_AFTER(&gd->gd_systimerq, scan2, info, node); 156 break; 157 } 158 scan1 = TAILQ_NEXT(scan1, node); 159 scan2 = TAILQ_PREV(scan2, systimerq, node); 160 } 161 } 162 info->flags = (info->flags | SYSTF_ONQUEUE) & ~SYSTF_IPIRUNNING; 163 info->queue = &gd->gd_systimerq; 164 } else { 165 #ifdef SMP 166 info->flags |= SYSTF_IPIRUNNING; 167 lwkt_send_ipiq(info->gd, (ipifunc1_t)systimer_add, info); 168 #else 169 panic("systimer_add: bad gd in info %p", info); 170 #endif 171 } 172 crit_exit(); 173 } 174 175 /* 176 * systimer_del() 177 * 178 * Delete a system timer. Only the owning cpu can delete a timer. 179 */ 180 void 181 systimer_del(systimer_t info) 182 { 183 KKASSERT(info->gd == mycpu && (info->flags & SYSTF_IPIRUNNING) == 0); 184 crit_enter(); 185 if (info->flags & SYSTF_ONQUEUE) { 186 TAILQ_REMOVE(info->queue, info, node); 187 info->flags &= ~SYSTF_ONQUEUE; 188 } 189 crit_exit(); 190 } 191 192 /* 193 * systimer_init_periodic() 194 * 195 * Initialize a periodic timer at the specified frequency and add 196 * it to the system. The frequency is uncompensated and approximate. 197 * 198 * Try to synchronize multi registrations of the same or similar 199 * frequencies so the hardware interrupt is able to dispatch several 200 * at together by adjusting the phase of the initial interrupt. This 201 * helps SMP. Note that we are not attempting to synchronize to 202 * the realtime clock. 203 */ 204 void 205 systimer_init_periodic(systimer_t info, void *func, void *data, int hz) 206 { 207 sysclock_t base_count; 208 209 bzero(info, sizeof(struct systimer)); 210 info->periodic = sys_cputimer->fromhz(hz); 211 base_count = sys_cputimer->count(); 212 base_count = base_count - (base_count % info->periodic); 213 info->time = base_count + info->periodic; 214 info->func = func; 215 info->data = data; 216 info->freq = hz; 217 info->which = sys_cputimer; 218 info->gd = mycpu; 219 systimer_add(info); 220 } 221 222 void 223 systimer_init_periodic_nq(systimer_t info, void *func, void *data, int hz) 224 { 225 sysclock_t base_count; 226 227 bzero(info, sizeof(struct systimer)); 228 info->periodic = sys_cputimer->fromhz(hz); 229 base_count = sys_cputimer->count(); 230 base_count = base_count - (base_count % info->periodic); 231 info->time = base_count + info->periodic; 232 info->func = func; 233 info->data = data; 234 info->freq = hz; 235 info->which = sys_cputimer; 236 info->gd = mycpu; 237 info->flags |= SYSTF_NONQUEUED; 238 systimer_add(info); 239 } 240 241 /* 242 * Adjust the periodic interval for a periodic timer which is already 243 * running. The current timeout is not effected. 244 */ 245 void 246 systimer_adjust_periodic(systimer_t info, int hz) 247 { 248 crit_enter(); 249 info->periodic = sys_cputimer->fromhz(hz); 250 info->freq = hz; 251 info->which = sys_cputimer; 252 crit_exit(); 253 } 254 255 /* 256 * systimer_init_oneshot() 257 * 258 * Initialize a periodic timer at the specified frequency and add 259 * it to the system. The frequency is uncompensated and approximate. 260 */ 261 void 262 systimer_init_oneshot(systimer_t info, void *func, void *data, int us) 263 { 264 bzero(info, sizeof(struct systimer)); 265 info->time = sys_cputimer->count() + sys_cputimer->fromus(us); 266 info->func = func; 267 info->data = data; 268 info->which = sys_cputimer; 269 info->gd = mycpu; 270 systimer_add(info); 271 } 272 273