xref: /freebsd/sys/kern/kern_et.c (revision 0f2bd1e89db1a2f09268edea21e0ead329e092df)
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_SPIN);
42 
43 SYSCTL_NODE(_kern, OID_AUTO, eventtimer, CTLFLAG_RW, 0, "Event timers");
44 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 		printf("Event timer \"%s\" frequency %ju Hz quality %d\n",
56 		    et->et_name, (uintmax_t)et->et_frequency,
57 		    et->et_quality);
58 	}
59 	et->et_sysctl = SYSCTL_ADD_NODE(NULL,
60 	    SYSCTL_STATIC_CHILDREN(_kern_eventtimer_et), OID_AUTO, et->et_name,
61 	    CTLFLAG_RW, 0, "event timer description");
62 	SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
63 	    "flags", CTLFLAG_RD, &(et->et_flags), 0,
64 	    "Event timer capabilities");
65 	SYSCTL_ADD_QUAD(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
66 	    "frequency", CTLFLAG_RD, &(et->et_frequency),
67 	    "Event timer base frequency");
68 	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
69 	    "quality", CTLFLAG_RD, &(et->et_quality), 0,
70 	    "Goodness of event timer");
71 	ET_LOCK();
72 	if (SLIST_EMPTY(&eventtimers) ||
73 	    SLIST_FIRST(&eventtimers)->et_quality < et->et_quality) {
74 		SLIST_INSERT_HEAD(&eventtimers, et, et_all);
75 	} else {
76 		SLIST_FOREACH(tmp, &eventtimers, et_all) {
77 			next = SLIST_NEXT(tmp, et_all);
78 			if (next == NULL || next->et_quality < et->et_quality) {
79 				SLIST_INSERT_AFTER(tmp, et, et_all);
80 				break;
81 			}
82 		}
83 	}
84 	ET_UNLOCK();
85 	return (0);
86 }
87 
88 /*
89  * Deregister event timer hardware.
90  */
91 int
92 et_deregister(struct eventtimer *et)
93 {
94 	int err = 0;
95 
96 	if (et->et_deregister_cb != NULL) {
97 		if ((err = et->et_deregister_cb(et, et->et_arg)) != 0)
98 			return (err);
99 	}
100 
101 	ET_LOCK();
102 	SLIST_REMOVE(&eventtimers, et, eventtimer, et_all);
103 	ET_UNLOCK();
104 	sysctl_remove_oid(et->et_sysctl, 1, 1);
105 	return (0);
106 }
107 
108 /*
109  * Find free event timer hardware with specified parameters.
110  */
111 struct eventtimer *
112 et_find(const char *name, int check, int want)
113 {
114 	struct eventtimer *et = NULL;
115 
116 	SLIST_FOREACH(et, &eventtimers, et_all) {
117 		if (et->et_active)
118 			continue;
119 		if (name != NULL && strcasecmp(et->et_name, name) != 0)
120 			continue;
121 		if (name == NULL && et->et_quality < 0)
122 			continue;
123 		if ((et->et_flags & check) != want)
124 			continue;
125 		break;
126 	}
127 	return (et);
128 }
129 
130 /*
131  * Initialize event timer hardware. Set callbacks.
132  */
133 int
134 et_init(struct eventtimer *et, et_event_cb_t *event,
135     et_deregister_cb_t *deregister, void *arg)
136 {
137 
138 	if (event == NULL)
139 		return (EINVAL);
140 	if (et->et_active)
141 		return (EBUSY);
142 
143 	et->et_active = 1;
144 	et->et_event_cb = event;
145 	et->et_deregister_cb = deregister;
146 	et->et_arg = arg;
147 	return (0);
148 }
149 
150 /*
151  * Start event timer hardware.
152  * first - delay before first tick.
153  * period - period of subsequent periodic ticks.
154  */
155 int
156 et_start(struct eventtimer *et,
157     struct bintime *first, struct bintime *period)
158 {
159 
160 	if (!et->et_active)
161 		return (ENXIO);
162 	if (first == NULL && period == NULL)
163 		return (EINVAL);
164 	if ((et->et_flags & ET_FLAGS_PERIODIC) == 0 &&
165 	    period != NULL)
166 		return (ENODEV);
167 	if ((et->et_flags & ET_FLAGS_ONESHOT) == 0 &&
168 	    period == NULL)
169 		return (ENODEV);
170 	if (first != NULL) {
171 		if (first->sec < et->et_min_period.sec ||
172 		    (first->sec == et->et_min_period.sec &&
173 		     first->frac < et->et_min_period.frac))
174 		        first = &et->et_min_period;
175 		if (first->sec > et->et_max_period.sec ||
176 		    (first->sec == et->et_max_period.sec &&
177 		     first->frac > et->et_max_period.frac))
178 		        first = &et->et_max_period;
179 	}
180 	if (period != NULL) {
181 		if (period->sec < et->et_min_period.sec ||
182 		    (period->sec == et->et_min_period.sec &&
183 		     period->frac < et->et_min_period.frac))
184 		        period = &et->et_min_period;
185 		if (period->sec > et->et_max_period.sec ||
186 		    (period->sec == et->et_max_period.sec &&
187 		     period->frac > et->et_max_period.frac))
188 		        period = &et->et_max_period;
189 	}
190 	if (et->et_start)
191 		return (et->et_start(et, first, period));
192 	return (0);
193 }
194 
195 /* Stop event timer hardware. */
196 int
197 et_stop(struct eventtimer *et)
198 {
199 
200 	if (!et->et_active)
201 		return (ENXIO);
202 	if (et->et_stop)
203 		return (et->et_stop(et));
204 	return (0);
205 }
206 
207 /* Mark event timer hardware as broken. */
208 int
209 et_ban(struct eventtimer *et)
210 {
211 
212 	et->et_flags &= ~(ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT);
213 	return (0);
214 }
215 
216 /* Free event timer hardware. */
217 int
218 et_free(struct eventtimer *et)
219 {
220 
221 	if (!et->et_active)
222 		return (ENXIO);
223 
224 	et->et_active = 0;
225 	return (0);
226 }
227 
228 /* Report list of supported event timers hardware via sysctl. */
229 static int
230 sysctl_kern_eventtimer_choice(SYSCTL_HANDLER_ARGS)
231 {
232 	char buf[512], *spc;
233 	struct eventtimer *et;
234 	int error, off;
235 
236 	spc = "";
237 	error = 0;
238 	off = 0;
239 	ET_LOCK();
240 	SLIST_FOREACH(et, &eventtimers, et_all) {
241 		off += snprintf(buf + off, sizeof(buf) - off, "%s%s(%d)",
242 		    spc, et->et_name, et->et_quality);
243 		spc = " ";
244 	}
245 	ET_UNLOCK();
246 	error = SYSCTL_OUT(req, buf, strlen(buf));
247 	return (error);
248 }
249 SYSCTL_PROC(_kern_eventtimer, OID_AUTO, choice,
250     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
251     0, 0, sysctl_kern_eventtimer_choice, "A", "Present event timers");
252 
253