xref: /freebsd/sys/kern/kern_et.c (revision d8a0fe102c0cfdfcd5b818f850eff09d8536c9bc)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2010-2013 Alexander Motin <mav@FreeBSD.org>
5  * All rights reserved.
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  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer,
12  *    without modification, immediately at the beginning of the file.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/sbuf.h>
35 #include <sys/sysctl.h>
36 #include <sys/systm.h>
37 #include <sys/queue.h>
38 #include <sys/timeet.h>
39 
40 #include "opt_timer.h"
41 
42 SLIST_HEAD(et_eventtimers_list, eventtimer);
43 static struct et_eventtimers_list eventtimers = SLIST_HEAD_INITIALIZER(et_eventtimers);
44 
45 struct mtx	et_eventtimers_mtx;
46 MTX_SYSINIT(et_eventtimers_init, &et_eventtimers_mtx, "et_mtx", MTX_DEF);
47 
48 SYSCTL_NODE(_kern, OID_AUTO, eventtimer, CTLFLAG_RW, 0, "Event timers");
49 static SYSCTL_NODE(_kern_eventtimer, OID_AUTO, et, CTLFLAG_RW, 0, "");
50 
51 /*
52  * Register a new event timer hardware.
53  */
54 int
55 et_register(struct eventtimer *et)
56 {
57 	struct eventtimer *tmp, *next;
58 
59 	if (et->et_quality >= 0 || bootverbose) {
60 		if (et->et_frequency == 0) {
61 			printf("Event timer \"%s\" quality %d\n",
62 			    et->et_name, et->et_quality);
63 		} else {
64 			printf("Event timer \"%s\" "
65 			    "frequency %ju Hz quality %d\n",
66 			    et->et_name, (uintmax_t)et->et_frequency,
67 			    et->et_quality);
68 		}
69 	}
70 	KASSERT(et->et_start, ("et_register: timer has no start function"));
71 	et->et_sysctl = SYSCTL_ADD_NODE_WITH_LABEL(NULL,
72 	    SYSCTL_STATIC_CHILDREN(_kern_eventtimer_et), OID_AUTO, et->et_name,
73 	    CTLFLAG_RW, 0, "event timer description", "eventtimer");
74 	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
75 	    "flags", CTLFLAG_RD, &(et->et_flags), 0,
76 	    "Event timer capabilities");
77 	SYSCTL_ADD_UQUAD(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
78 	    "frequency", CTLFLAG_RD, &(et->et_frequency),
79 	    "Event timer base frequency");
80 	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
81 	    "quality", CTLFLAG_RD, &(et->et_quality), 0,
82 	    "Goodness of event timer");
83 	ET_LOCK();
84 	if (SLIST_EMPTY(&eventtimers) ||
85 	    SLIST_FIRST(&eventtimers)->et_quality < et->et_quality) {
86 		SLIST_INSERT_HEAD(&eventtimers, et, et_all);
87 	} else {
88 		SLIST_FOREACH(tmp, &eventtimers, et_all) {
89 			next = SLIST_NEXT(tmp, et_all);
90 			if (next == NULL || next->et_quality < et->et_quality) {
91 				SLIST_INSERT_AFTER(tmp, et, et_all);
92 				break;
93 			}
94 		}
95 	}
96 	ET_UNLOCK();
97 	return (0);
98 }
99 
100 /*
101  * Deregister event timer hardware.
102  */
103 int
104 et_deregister(struct eventtimer *et)
105 {
106 	int err = 0;
107 
108 	if (et->et_deregister_cb != NULL) {
109 		if ((err = et->et_deregister_cb(et, et->et_arg)) != 0)
110 			return (err);
111 	}
112 
113 	ET_LOCK();
114 	SLIST_REMOVE(&eventtimers, et, eventtimer, et_all);
115 	ET_UNLOCK();
116 	sysctl_remove_oid(et->et_sysctl, 1, 1);
117 	return (0);
118 }
119 
120 /*
121  * Change the frequency of the given timer.  If it is the active timer,
122  * reconfigure it on all CPUs (reschedules all current events based on the new
123  * timer frequency).
124  */
125 void
126 et_change_frequency(struct eventtimer *et, uint64_t newfreq)
127 {
128 
129 #ifndef NO_EVENTTIMERS
130 	cpu_et_frequency(et, newfreq);
131 #endif
132 }
133 
134 /*
135  * Find free event timer hardware with specified parameters.
136  */
137 struct eventtimer *
138 et_find(const char *name, int check, int want)
139 {
140 	struct eventtimer *et = NULL;
141 
142 	SLIST_FOREACH(et, &eventtimers, et_all) {
143 		if (et->et_active)
144 			continue;
145 		if (name != NULL && strcasecmp(et->et_name, name) != 0)
146 			continue;
147 		if (name == NULL && et->et_quality < 0)
148 			continue;
149 		if ((et->et_flags & check) != want)
150 			continue;
151 		break;
152 	}
153 	return (et);
154 }
155 
156 /*
157  * Initialize event timer hardware. Set callbacks.
158  */
159 int
160 et_init(struct eventtimer *et, et_event_cb_t *event,
161     et_deregister_cb_t *deregister, void *arg)
162 {
163 
164 	if (event == NULL)
165 		return (EINVAL);
166 	if (et->et_active)
167 		return (EBUSY);
168 
169 	et->et_active = 1;
170 	et->et_event_cb = event;
171 	et->et_deregister_cb = deregister;
172 	et->et_arg = arg;
173 	return (0);
174 }
175 
176 /*
177  * Start event timer hardware.
178  * first - delay before first tick.
179  * period - period of subsequent periodic ticks.
180  */
181 int
182 et_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
183 {
184 
185 	if (!et->et_active)
186 		return (ENXIO);
187 	KASSERT(period >= 0, ("et_start: negative period"));
188 	KASSERT((et->et_flags & ET_FLAGS_PERIODIC) || period == 0,
189 		("et_start: period specified for oneshot-only timer"));
190 	KASSERT((et->et_flags & ET_FLAGS_ONESHOT) || period != 0,
191 		("et_start: period not specified for periodic-only timer"));
192 	if (period != 0) {
193 		if (period < et->et_min_period)
194 		        period = et->et_min_period;
195 		else if (period > et->et_max_period)
196 		        period = et->et_max_period;
197 	}
198 	if (period == 0 || first != 0) {
199 		if (first < et->et_min_period)
200 		        first = et->et_min_period;
201 		else if (first > et->et_max_period)
202 		        first = et->et_max_period;
203 	}
204 	return (et->et_start(et, first, period));
205 }
206 
207 /* Stop event timer hardware. */
208 int
209 et_stop(struct eventtimer *et)
210 {
211 
212 	if (!et->et_active)
213 		return (ENXIO);
214 	if (et->et_stop)
215 		return (et->et_stop(et));
216 	return (0);
217 }
218 
219 /* Mark event timer hardware as broken. */
220 int
221 et_ban(struct eventtimer *et)
222 {
223 
224 	et->et_flags &= ~(ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT);
225 	return (0);
226 }
227 
228 /* Free event timer hardware. */
229 int
230 et_free(struct eventtimer *et)
231 {
232 
233 	if (!et->et_active)
234 		return (ENXIO);
235 
236 	et->et_active = 0;
237 	return (0);
238 }
239 
240 /* Report list of supported event timer hardware via sysctl. */
241 static int
242 sysctl_kern_eventtimer_choice(SYSCTL_HANDLER_ARGS)
243 {
244 	struct sbuf sb;
245 	struct eventtimer *et;
246 	int error;
247 
248 	sbuf_new(&sb, NULL, 256, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
249 
250 	ET_LOCK();
251 	SLIST_FOREACH(et, &eventtimers, et_all) {
252 		if (et != SLIST_FIRST(&eventtimers))
253 			sbuf_putc(&sb, ' ');
254 		sbuf_printf(&sb, "%s(%d)", et->et_name, et->et_quality);
255 	}
256 	ET_UNLOCK();
257 
258 	error = sbuf_finish(&sb);
259 	if (error == 0)
260 		error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
261 	sbuf_delete(&sb);
262 	return (error);
263 }
264 SYSCTL_PROC(_kern_eventtimer, OID_AUTO, choice,
265     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
266     0, 0, sysctl_kern_eventtimer_choice, "A", "Present event timers");
267 
268