FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_et.c
1 /*-
2 * Copyright (c) 2010 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("$FreeBSD$");
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 SLIST_HEAD(et_eventtimers_list, eventtimer);
38 static struct et_eventtimers_list eventtimers = SLIST_HEAD_INITIALIZER(et_eventtimers);
39
40 struct mtx et_eventtimers_mtx;
41 MTX_SYSINIT(et_eventtimers_init, &et_eventtimers_mtx, "et_mtx", MTX_DEF);
42
43 SYSCTL_NODE(_kern, OID_AUTO, eventtimer, CTLFLAG_RW, 0, "Event timers");
44 static SYSCTL_NODE(_kern_eventtimer, OID_AUTO, et, CTLFLAG_RW, 0, "");
45
46 /*
47 * Register a new event timer hardware.
48 */
49 int
50 et_register(struct eventtimer *et)
51 {
52 struct eventtimer *tmp, *next;
53
54 if (et->et_quality >= 0 || bootverbose) {
55 if (et->et_frequency == 0) {
56 printf("Event timer \"%s\" quality %d\n",
57 et->et_name, et->et_quality);
58 } else {
59 printf("Event timer \"%s\" "
60 "frequency %ju Hz quality %d\n",
61 et->et_name, (uintmax_t)et->et_frequency,
62 et->et_quality);
63 }
64 }
65 et->et_sysctl = SYSCTL_ADD_NODE(NULL,
66 SYSCTL_STATIC_CHILDREN(_kern_eventtimer_et), OID_AUTO, et->et_name,
67 CTLFLAG_RW, 0, "event timer description");
68 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
69 "flags", CTLFLAG_RD, &(et->et_flags), 0,
70 "Event timer capabilities");
71 SYSCTL_ADD_UQUAD(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
72 "frequency", CTLFLAG_RD, &(et->et_frequency),
73 "Event timer base frequency");
74 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
75 "quality", CTLFLAG_RD, &(et->et_quality), 0,
76 "Goodness of event timer");
77 ET_LOCK();
78 if (SLIST_EMPTY(&eventtimers) ||
79 SLIST_FIRST(&eventtimers)->et_quality < et->et_quality) {
80 SLIST_INSERT_HEAD(&eventtimers, et, et_all);
81 } else {
82 SLIST_FOREACH(tmp, &eventtimers, et_all) {
83 next = SLIST_NEXT(tmp, et_all);
84 if (next == NULL || next->et_quality < et->et_quality) {
85 SLIST_INSERT_AFTER(tmp, et, et_all);
86 break;
87 }
88 }
89 }
90 ET_UNLOCK();
91 return (0);
92 }
93
94 /*
95 * Deregister event timer hardware.
96 */
97 int
98 et_deregister(struct eventtimer *et)
99 {
100 int err = 0;
101
102 if (et->et_deregister_cb != NULL) {
103 if ((err = et->et_deregister_cb(et, et->et_arg)) != 0)
104 return (err);
105 }
106
107 ET_LOCK();
108 SLIST_REMOVE(&eventtimers, et, eventtimer, et_all);
109 ET_UNLOCK();
110 sysctl_remove_oid(et->et_sysctl, 1, 1);
111 return (0);
112 }
113
114 /*
115 * Find free event timer hardware with specified parameters.
116 */
117 struct eventtimer *
118 et_find(const char *name, int check, int want)
119 {
120 struct eventtimer *et = NULL;
121
122 SLIST_FOREACH(et, &eventtimers, et_all) {
123 if (et->et_active)
124 continue;
125 if (name != NULL && strcasecmp(et->et_name, name) != 0)
126 continue;
127 if (name == NULL && et->et_quality < 0)
128 continue;
129 if ((et->et_flags & check) != want)
130 continue;
131 break;
132 }
133 return (et);
134 }
135
136 /*
137 * Initialize event timer hardware. Set callbacks.
138 */
139 int
140 et_init(struct eventtimer *et, et_event_cb_t *event,
141 et_deregister_cb_t *deregister, void *arg)
142 {
143
144 if (event == NULL)
145 return (EINVAL);
146 if (et->et_active)
147 return (EBUSY);
148
149 et->et_active = 1;
150 et->et_event_cb = event;
151 et->et_deregister_cb = deregister;
152 et->et_arg = arg;
153 return (0);
154 }
155
156 /*
157 * Start event timer hardware.
158 * first - delay before first tick.
159 * period - period of subsequent periodic ticks.
160 */
161 int
162 et_start(struct eventtimer *et,
163 struct bintime *first, struct bintime *period)
164 {
165
166 if (!et->et_active)
167 return (ENXIO);
168 if (first == NULL && period == NULL)
169 return (EINVAL);
170 if ((et->et_flags & ET_FLAGS_PERIODIC) == 0 &&
171 period != NULL)
172 return (ENODEV);
173 if ((et->et_flags & ET_FLAGS_ONESHOT) == 0 &&
174 period == NULL)
175 return (ENODEV);
176 if (first != NULL) {
177 if (first->sec < et->et_min_period.sec ||
178 (first->sec == et->et_min_period.sec &&
179 first->frac < et->et_min_period.frac))
180 first = &et->et_min_period;
181 if (first->sec > et->et_max_period.sec ||
182 (first->sec == et->et_max_period.sec &&
183 first->frac > et->et_max_period.frac))
184 first = &et->et_max_period;
185 }
186 if (period != NULL) {
187 if (period->sec < et->et_min_period.sec ||
188 (period->sec == et->et_min_period.sec &&
189 period->frac < et->et_min_period.frac))
190 period = &et->et_min_period;
191 if (period->sec > et->et_max_period.sec ||
192 (period->sec == et->et_max_period.sec &&
193 period->frac > et->et_max_period.frac))
194 period = &et->et_max_period;
195 }
196 if (et->et_start)
197 return (et->et_start(et, first, period));
198 return (0);
199 }
200
201 /* Stop event timer hardware. */
202 int
203 et_stop(struct eventtimer *et)
204 {
205
206 if (!et->et_active)
207 return (ENXIO);
208 if (et->et_stop)
209 return (et->et_stop(et));
210 return (0);
211 }
212
213 /* Mark event timer hardware as broken. */
214 int
215 et_ban(struct eventtimer *et)
216 {
217
218 et->et_flags &= ~(ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT);
219 return (0);
220 }
221
222 /* Free event timer hardware. */
223 int
224 et_free(struct eventtimer *et)
225 {
226
227 if (!et->et_active)
228 return (ENXIO);
229
230 et->et_active = 0;
231 return (0);
232 }
233
234 /* Report list of supported event timers hardware via sysctl. */
235 static int
236 sysctl_kern_eventtimer_choice(SYSCTL_HANDLER_ARGS)
237 {
238 char buf[512], *spc;
239 struct eventtimer *et;
240 int error, off;
241
242 spc = "";
243 error = 0;
244 buf[0] = 0;
245 off = 0;
246 ET_LOCK();
247 SLIST_FOREACH(et, &eventtimers, et_all) {
248 off += snprintf(buf + off, sizeof(buf) - off, "%s%s(%d)",
249 spc, et->et_name, et->et_quality);
250 spc = " ";
251 }
252 ET_UNLOCK();
253 error = SYSCTL_OUT(req, buf, strlen(buf));
254 return (error);
255 }
256 SYSCTL_PROC(_kern_eventtimer, OID_AUTO, choice,
257 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
258 0, 0, sysctl_kern_eventtimer_choice, "A", "Present event timers");
259
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