kern_et.c revision 210346 
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: head/sys/kern/kern_et.c 210346 2010-07-21 12:23:49Z mav $");
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
37SLIST_HEAD(et_eventtimers_list, eventtimer);
38static struct et_eventtimers_list eventtimers = SLIST_HEAD_INITIALIZER(et_eventtimers);
39
40struct mtx	et_eventtimers_mtx;
41MTX_SYSINIT(et_eventtimers_init, &et_eventtimers_mtx, "et_mtx", MTX_SPIN);
42
43SYSCTL_NODE(_kern, OID_AUTO, eventtimer, CTLFLAG_RW, 0, "Event timers");
44SYSCTL_NODE(_kern_eventtimer, OID_AUTO, et, CTLFLAG_RW, 0, "");
45
46/*
47 * Register a new event timer hardware.
48 */
49int
50et_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 */
91int
92et_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 */
111struct eventtimer *
112et_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 */
133int
134et_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 */
155int
156et_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. */
196int
197et_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. */
208int
209et_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. */
217int
218et_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. */
229static int
230sysctl_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}
249SYSCTL_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