FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_et.c
1 /*-
2 * Copyright (c) 2010-2013 Alexander Motin <mav@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer,
10 * without modification, immediately at the beginning of the file.
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 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/10.1/sys/kern/kern_et.c 266347 2014-05-17 20:10:12Z ian $");
29
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/sysctl.h>
33 #include <sys/systm.h>
34 #include <sys/queue.h>
35 #include <sys/timeet.h>
36
37 #include "opt_timer.h"
38
39 SLIST_HEAD(et_eventtimers_list, eventtimer);
40 static struct et_eventtimers_list eventtimers = SLIST_HEAD_INITIALIZER(et_eventtimers);
41
42 struct mtx et_eventtimers_mtx;
43 MTX_SYSINIT(et_eventtimers_init, &et_eventtimers_mtx, "et_mtx", MTX_DEF);
44
45 SYSCTL_NODE(_kern, OID_AUTO, eventtimer, CTLFLAG_RW, 0, "Event timers");
46 static SYSCTL_NODE(_kern_eventtimer, OID_AUTO, et, CTLFLAG_RW, 0, "");
47
48 /*
49 * Register a new event timer hardware.
50 */
51 int
52 et_register(struct eventtimer *et)
53 {
54 struct eventtimer *tmp, *next;
55
56 if (et->et_quality >= 0 || bootverbose) {
57 if (et->et_frequency == 0) {
58 printf("Event timer \"%s\" quality %d\n",
59 et->et_name, et->et_quality);
60 } else {
61 printf("Event timer \"%s\" "
62 "frequency %ju Hz quality %d\n",
63 et->et_name, (uintmax_t)et->et_frequency,
64 et->et_quality);
65 }
66 }
67 KASSERT(et->et_start, ("et_register: timer has no start function"));
68 et->et_sysctl = SYSCTL_ADD_NODE(NULL,
69 SYSCTL_STATIC_CHILDREN(_kern_eventtimer_et), OID_AUTO, et->et_name,
70 CTLFLAG_RW, 0, "event timer description");
71 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
72 "flags", CTLFLAG_RD, &(et->et_flags), 0,
73 "Event timer capabilities");
74 SYSCTL_ADD_UQUAD(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
75 "frequency", CTLFLAG_RD, &(et->et_frequency),
76 "Event timer base frequency");
77 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
78 "quality", CTLFLAG_RD, &(et->et_quality), 0,
79 "Goodness of event timer");
80 ET_LOCK();
81 if (SLIST_EMPTY(&eventtimers) ||
82 SLIST_FIRST(&eventtimers)->et_quality < et->et_quality) {
83 SLIST_INSERT_HEAD(&eventtimers, et, et_all);
84 } else {
85 SLIST_FOREACH(tmp, &eventtimers, et_all) {
86 next = SLIST_NEXT(tmp, et_all);
87 if (next == NULL || next->et_quality < et->et_quality) {
88 SLIST_INSERT_AFTER(tmp, et, et_all);
89 break;
90 }
91 }
92 }
93 ET_UNLOCK();
94 return (0);
95 }
96
97 /*
98 * Deregister event timer hardware.
99 */
100 int
101 et_deregister(struct eventtimer *et)
102 {
103 int err = 0;
104
105 if (et->et_deregister_cb != NULL) {
106 if ((err = et->et_deregister_cb(et, et->et_arg)) != 0)
107 return (err);
108 }
109
110 ET_LOCK();
111 SLIST_REMOVE(&eventtimers, et, eventtimer, et_all);
112 ET_UNLOCK();
113 sysctl_remove_oid(et->et_sysctl, 1, 1);
114 return (0);
115 }
116
117 /*
118 * Change the frequency of the given timer. If it is the active timer,
119 * reconfigure it on all CPUs (reschedules all current events based on the new
120 * timer frequency).
121 */
122 void
123 et_change_frequency(struct eventtimer *et, uint64_t newfreq)
124 {
125
126 #ifndef NO_EVENTTIMERS
127 cpu_et_frequency(et, newfreq);
128 #endif
129 }
130
131 /*
132 * Find free event timer hardware with specified parameters.
133 */
134 struct eventtimer *
135 et_find(const char *name, int check, int want)
136 {
137 struct eventtimer *et = NULL;
138
139 SLIST_FOREACH(et, &eventtimers, et_all) {
140 if (et->et_active)
141 continue;
142 if (name != NULL && strcasecmp(et->et_name, name) != 0)
143 continue;
144 if (name == NULL && et->et_quality < 0)
145 continue;
146 if ((et->et_flags & check) != want)
147 continue;
148 break;
149 }
150 return (et);
151 }
152
153 /*
154 * Initialize event timer hardware. Set callbacks.
155 */
156 int
157 et_init(struct eventtimer *et, et_event_cb_t *event,
158 et_deregister_cb_t *deregister, void *arg)
159 {
160
161 if (event == NULL)
162 return (EINVAL);
163 if (et->et_active)
164 return (EBUSY);
165
166 et->et_active = 1;
167 et->et_event_cb = event;
168 et->et_deregister_cb = deregister;
169 et->et_arg = arg;
170 return (0);
171 }
172
173 /*
174 * Start event timer hardware.
175 * first - delay before first tick.
176 * period - period of subsequent periodic ticks.
177 */
178 int
179 et_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
180 {
181
182 if (!et->et_active)
183 return (ENXIO);
184 KASSERT(period >= 0, ("et_start: negative period"));
185 KASSERT((et->et_flags & ET_FLAGS_PERIODIC) || period == 0,
186 ("et_start: period specified for oneshot-only timer"));
187 KASSERT((et->et_flags & ET_FLAGS_ONESHOT) || period != 0,
188 ("et_start: period not specified for periodic-only timer"));
189 if (period != 0) {
190 if (period < et->et_min_period)
191 period = et->et_min_period;
192 else if (period > et->et_max_period)
193 period = et->et_max_period;
194 }
195 if (period == 0 || first != 0) {
196 if (first < et->et_min_period)
197 first = et->et_min_period;
198 else if (first > et->et_max_period)
199 first = et->et_max_period;
200 }
201 return (et->et_start(et, first, period));
202 }
203
204 /* Stop event timer hardware. */
205 int
206 et_stop(struct eventtimer *et)
207 {
208
209 if (!et->et_active)
210 return (ENXIO);
211 if (et->et_stop)
212 return (et->et_stop(et));
213 return (0);
214 }
215
216 /* Mark event timer hardware as broken. */
217 int
218 et_ban(struct eventtimer *et)
219 {
220
221 et->et_flags &= ~(ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT);
222 return (0);
223 }
224
225 /* Free event timer hardware. */
226 int
227 et_free(struct eventtimer *et)
228 {
229
230 if (!et->et_active)
231 return (ENXIO);
232
233 et->et_active = 0;
234 return (0);
235 }
236
237 /* Report list of supported event timers hardware via sysctl. */
238 static int
239 sysctl_kern_eventtimer_choice(SYSCTL_HANDLER_ARGS)
240 {
241 char buf[512], *spc;
242 struct eventtimer *et;
243 int error, off;
244
245 spc = "";
246 error = 0;
247 buf[0] = 0;
248 off = 0;
249 ET_LOCK();
250 SLIST_FOREACH(et, &eventtimers, et_all) {
251 off += snprintf(buf + off, sizeof(buf) - off, "%s%s(%d)",
252 spc, et->et_name, et->et_quality);
253 spc = " ";
254 }
255 ET_UNLOCK();
256 error = SYSCTL_OUT(req, buf, strlen(buf));
257 return (error);
258 }
259 SYSCTL_PROC(_kern_eventtimer, OID_AUTO, choice,
260 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
261 0, 0, sysctl_kern_eventtimer_choice, "A", "Present event timers");
262
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