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 1.12 2007/10/16 11:12:59 sephe 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 in_ipi, 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, detect a loss of the systimer. Note 94 * that the in-progress systimer pointer can only be used to 95 * detect a loss of the systimer, it is only useful within 96 * this code sequence and becomes stale otherwise. 97 */ 98 info->flags &= ~SYSTF_ONQUEUE; 99 TAILQ_REMOVE(info->queue, info, node); 100 gd->gd_systimer_inprog = info; 101 crit_exit(); 102 info->func(info, in_ipi, frame); 103 crit_enter(); 104 105 /* 106 * The caller may deleted or even re-queue the systimer itself 107 * with a delete/add sequence. If the caller does not mess with 108 * the systimer we will requeue the periodic interval automatically. 109 * 110 * If this is a non-queued periodic interrupt, do not allow multiple 111 * events to build up (used for things like the callout timer to 112 * prevent premature timeouts due to long interrupt disablements, 113 * BIOS 8254 glitching, and so forth). However, we still want to 114 * keep things synchronized between cpus for efficient handling of 115 * the timer interrupt so jump in multiples of the periodic rate. 116 */ 117 if (gd->gd_systimer_inprog == info && info->periodic) { 118 if (info->which != sys_cputimer) { 119 info->periodic = sys_cputimer->fromhz(info->freq); 120 info->which = sys_cputimer; 121 } 122 info->time += info->periodic; 123 if ((info->flags & SYSTF_NONQUEUED) && 124 (int)(info->time - time) <= 0 125 ) { 126 info->time += ((time - info->time + info->periodic - 1) / 127 info->periodic) * info->periodic; 128 } 129 systimer_add(info); 130 } 131 gd->gd_systimer_inprog = NULL; 132 } 133 --gd->gd_syst_nest; 134 crit_exit(); 135 } 136 137 void 138 systimer_intr_enable(void) 139 { 140 cputimer_intr_enable(); 141 } 142 143 /* 144 * MPSAFE 145 */ 146 void 147 systimer_add(systimer_t info) 148 { 149 struct globaldata *gd = mycpu; 150 151 KKASSERT((info->flags & SYSTF_ONQUEUE) == 0); 152 crit_enter(); 153 if (info->gd == gd) { 154 systimer_t scan1; 155 systimer_t scan2; 156 scan1 = TAILQ_FIRST(&gd->gd_systimerq); 157 if (scan1 == NULL || (int)(scan1->time - info->time) > 0) { 158 cputimer_intr_reload(info->time - sys_cputimer->count()); 159 TAILQ_INSERT_HEAD(&gd->gd_systimerq, info, node); 160 } else { 161 scan2 = TAILQ_LAST(&gd->gd_systimerq, systimerq); 162 for (;;) { 163 if (scan1 == NULL) { 164 TAILQ_INSERT_TAIL(&gd->gd_systimerq, info, node); 165 break; 166 } 167 if ((int)(scan1->time - info->time) > 0) { 168 TAILQ_INSERT_BEFORE(scan1, info, node); 169 break; 170 } 171 if ((int)(scan2->time - info->time) <= 0) { 172 TAILQ_INSERT_AFTER(&gd->gd_systimerq, scan2, info, node); 173 break; 174 } 175 scan1 = TAILQ_NEXT(scan1, node); 176 scan2 = TAILQ_PREV(scan2, systimerq, node); 177 } 178 } 179 info->flags = (info->flags | SYSTF_ONQUEUE) & ~SYSTF_IPIRUNNING; 180 info->queue = &gd->gd_systimerq; 181 } else { 182 #ifdef SMP 183 KKASSERT((info->flags & SYSTF_IPIRUNNING) == 0); 184 info->flags |= SYSTF_IPIRUNNING; 185 lwkt_send_ipiq(info->gd, (ipifunc1_t)systimer_add, info); 186 #else 187 panic("systimer_add: bad gd in info %p", info); 188 #endif 189 } 190 crit_exit(); 191 } 192 193 /* 194 * systimer_del() 195 * 196 * Delete a system timer. Only the owning cpu can delete a timer. 197 * 198 * MPSAFE 199 */ 200 void 201 systimer_del(systimer_t info) 202 { 203 struct globaldata *gd = info->gd; 204 205 KKASSERT(gd == mycpu && (info->flags & SYSTF_IPIRUNNING) == 0); 206 207 crit_enter(); 208 209 if (info->flags & SYSTF_ONQUEUE) { 210 TAILQ_REMOVE(info->queue, info, node); 211 info->flags &= ~SYSTF_ONQUEUE; 212 } 213 214 /* 215 * Deal with dispatch races by clearing the in-progress systimer 216 * pointer. Only a direct pointer comparison can be used, the 217 * actual contents of the structure gd_systimer_inprog points to, 218 * if not equal to info, may be stale. 219 */ 220 if (gd->gd_systimer_inprog == info) 221 gd->gd_systimer_inprog = NULL; 222 223 crit_exit(); 224 } 225 226 /* 227 * systimer_init_periodic() 228 * 229 * Initialize a periodic timer at the specified frequency and add 230 * it to the system. The frequency is uncompensated and approximate. 231 * 232 * Try to synchronize multi registrations of the same or similar 233 * frequencies so the hardware interrupt is able to dispatch several 234 * at together by adjusting the phase of the initial interrupt. This 235 * helps SMP. Note that we are not attempting to synchronize to 236 * the realtime clock. 237 */ 238 void 239 systimer_init_periodic(systimer_t info, systimer_func_t func, void *data, 240 int hz) 241 { 242 sysclock_t base_count; 243 244 bzero(info, sizeof(struct systimer)); 245 info->periodic = sys_cputimer->fromhz(hz); 246 base_count = sys_cputimer->count(); 247 base_count = base_count - (base_count % info->periodic); 248 info->time = base_count + info->periodic; 249 info->func = func; 250 info->data = data; 251 info->freq = hz; 252 info->which = sys_cputimer; 253 info->gd = mycpu; 254 systimer_add(info); 255 } 256 257 void 258 systimer_init_periodic_nq(systimer_t info, systimer_func_t func, void *data, 259 int hz) 260 { 261 sysclock_t base_count; 262 263 bzero(info, sizeof(struct systimer)); 264 info->periodic = sys_cputimer->fromhz(hz); 265 base_count = sys_cputimer->count(); 266 base_count = base_count - (base_count % info->periodic); 267 info->time = base_count + info->periodic; 268 info->func = func; 269 info->data = data; 270 info->freq = hz; 271 info->which = sys_cputimer; 272 info->gd = mycpu; 273 info->flags |= SYSTF_NONQUEUED; 274 systimer_add(info); 275 } 276 277 /* 278 * Adjust the periodic interval for a periodic timer which is already 279 * running. The current timeout is not effected. 280 */ 281 void 282 systimer_adjust_periodic(systimer_t info, int hz) 283 { 284 crit_enter(); 285 info->periodic = sys_cputimer->fromhz(hz); 286 info->freq = hz; 287 info->which = sys_cputimer; 288 crit_exit(); 289 } 290 291 /* 292 * systimer_init_oneshot() 293 * 294 * Initialize a periodic timer at the specified frequency and add 295 * it to the system. The frequency is uncompensated and approximate. 296 */ 297 void 298 systimer_init_oneshot(systimer_t info, systimer_func_t func, void *data, int us) 299 { 300 bzero(info, sizeof(struct systimer)); 301 info->time = sys_cputimer->count() + sys_cputimer->fromus(us); 302 info->func = func; 303 info->data = data; 304 info->which = sys_cputimer; 305 info->gd = mycpu; 306 systimer_add(info); 307 } 308