2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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
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.
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,
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27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sys/kern/kern_systimer.c,v 1.6 2005/03/27 19:25:09 dillon Exp $
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.
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.
46 * Notes on machine-dependant code (in arch/arch/systimer.c)
48 * cputimer_intr_reload() Reload the one-shot (per-cpu basis)
50 * cputimer_count() Get the current absolute sysclock_t value.
53 #include <sys/param.h>
54 #include <sys/kernel.h>
55 #include <sys/systm.h>
56 #include <sys/thread.h>
57 #include <sys/globaldata.h>
58 #include <sys/systimer.h>
59 #include <sys/thread2.h>
62 * Execute ready systimers. Called directly from the platform-specific
63 * one-shot timer clock interrupt (e.g. clkintr()) or via an IPI. May
64 * be called simultaniously on multiple cpus and always operations on
65 * the current cpu's queue. Systimer functions are responsible for calling
66 * hardclock, statclock, and other finely-timed routines.
69 systimer_intr(sysclock_t *timep, struct intrframe *frame)
71 globaldata_t gd = mycpu;
72 sysclock_t time = *timep;
80 while ((info = TAILQ_FIRST(&gd->gd_systimerq)) != NULL) {
82 * If we haven't reached the requested time, tell the cputimer
83 * how much is left and break out.
85 if ((int)(info->time - time) > 0) {
86 cputimer_intr_reload(info->time - time);
93 info->flags &= ~SYSTF_ONQUEUE;
94 TAILQ_REMOVE(info->queue, info, node);
96 info->func(info, frame);
100 * Reinstall if periodic. If this is a non-queued periodic
101 * interrupt do not allow multiple events to build up (used
102 * for things like the callout timer to prevent premature timeouts
103 * due to long interrupt disablements, BIOS 8254 glitching, and so
104 * forth). However, we still want to keep things synchronized between
105 * cpus for efficient handling of the timer interrupt so jump in
106 * multiples of the periodic rate.
108 if (info->periodic) {
109 info->time += info->periodic;
110 if ((info->flags & SYSTF_NONQUEUED) &&
111 (int)(info->time - time) <= 0
113 info->time += ((time - info->time + info->periodic - 1) /
114 info->periodic) * info->periodic;
124 systimer_add(systimer_t info)
126 struct globaldata *gd = mycpu;
128 KKASSERT((info->flags & (SYSTF_ONQUEUE|SYSTF_IPIRUNNING)) == 0);
130 if (info->gd == gd) {
133 scan1 = TAILQ_FIRST(&gd->gd_systimerq);
134 if (scan1 == NULL || (int)(scan1->time - info->time) > 0) {
135 cputimer_intr_reload(info->time - cputimer_count());
136 TAILQ_INSERT_HEAD(&gd->gd_systimerq, info, node);
138 scan2 = TAILQ_LAST(&gd->gd_systimerq, systimerq);
141 TAILQ_INSERT_TAIL(&gd->gd_systimerq, info, node);
144 if ((int)(scan1->time - info->time) > 0) {
145 TAILQ_INSERT_BEFORE(scan1, info, node);
148 if ((int)(scan2->time - info->time) <= 0) {
149 TAILQ_INSERT_AFTER(&gd->gd_systimerq, scan2, info, node);
152 scan1 = TAILQ_NEXT(scan1, node);
153 scan2 = TAILQ_PREV(scan2, systimerq, node);
156 info->flags = (info->flags | SYSTF_ONQUEUE) & ~SYSTF_IPIRUNNING;
157 info->queue = &gd->gd_systimerq;
159 info->flags |= SYSTF_IPIRUNNING;
160 lwkt_send_ipiq(info->gd, (ipifunc_t)systimer_add, info);
168 * Delete a system timer. Only the owning cpu can delete a timer.
171 systimer_del(systimer_t info)
173 KKASSERT(info->gd == mycpu && (info->flags & SYSTF_IPIRUNNING) == 0);
175 if (info->flags & SYSTF_ONQUEUE) {
176 TAILQ_REMOVE(info->queue, info, node);
177 info->flags &= ~SYSTF_ONQUEUE;
183 * systimer_init_periodic()
185 * Initialize a periodic timer at the specified frequency and add
186 * it to the system. The frequency is uncompensated and approximate.
188 * Try to synchronize multi registrations of the same or similar
189 * frequencies so the hardware interrupt is able to dispatch several
190 * at together by adjusting the phase of the initial interrupt. This
191 * helps SMP. Note that we are not attempting to synchronize to
192 * the realtime clock.
195 systimer_init_periodic(systimer_t info, void *func, void *data, int hz)
197 sysclock_t base_count;
199 bzero(info, sizeof(struct systimer));
200 info->periodic = cputimer_fromhz(hz);
201 base_count = cputimer_count();
202 base_count = base_count - (base_count % info->periodic);
203 info->time = base_count + info->periodic;
211 systimer_init_periodic_nq(systimer_t info, void *func, void *data, int hz)
213 sysclock_t base_count;
215 bzero(info, sizeof(struct systimer));
216 info->periodic = cputimer_fromhz(hz);
217 base_count = cputimer_count();
218 base_count = base_count - (base_count % info->periodic);
219 info->time = base_count + info->periodic;
223 info->flags |= SYSTF_NONQUEUED;
228 * systimer_init_oneshot()
230 * Initialize a periodic timer at the specified frequency and add
231 * it to the system. The frequency is uncompensated and approximate.
234 systimer_init_oneshot(systimer_t info, void *func, void *data, int us)
236 bzero(info, sizeof(struct systimer));
237 info->time = cputimer_count() + cputimer_fromus(us);