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("$FreeBSD$");
29
30#include <sys/param.h>
31#include <sys/kernel.h>
32#include <sys/sbuf.h>
33#include <sys/sysctl.h>
34#include <sys/systm.h>
35#include <sys/queue.h>
36#include <sys/timeet.h>
37
38#include "opt_timer.h"
39
40SLIST_HEAD(et_eventtimers_list, eventtimer);
41static struct et_eventtimers_list eventtimers = SLIST_HEAD_INITIALIZER(et_eventtimers);
42
43struct mtx	et_eventtimers_mtx;
44MTX_SYSINIT(et_eventtimers_init, &et_eventtimers_mtx, "et_mtx", MTX_DEF);
45
46SYSCTL_NODE(_kern, OID_AUTO, eventtimer, CTLFLAG_RW, 0, "Event timers");
47static SYSCTL_NODE(_kern_eventtimer, OID_AUTO, et, CTLFLAG_RW, 0, "");
48
49/*
50 * Register a new event timer hardware.
51 */
52int
53et_register(struct eventtimer *et)
54{
55	struct eventtimer *tmp, *next;
56
57	if (et->et_quality >= 0 || bootverbose) {
58		if (et->et_frequency == 0) {
59			printf("Event timer \"%s\" quality %d\n",
60			    et->et_name, et->et_quality);
61		} else {
62			printf("Event timer \"%s\" "
63			    "frequency %ju Hz quality %d\n",
64			    et->et_name, (uintmax_t)et->et_frequency,
65			    et->et_quality);
66		}
67	}
68	KASSERT(et->et_start, ("et_register: timer has no start function"));
69	et->et_sysctl = SYSCTL_ADD_NODE(NULL,
70	    SYSCTL_STATIC_CHILDREN(_kern_eventtimer_et), OID_AUTO, et->et_name,
71	    CTLFLAG_RW, 0, "event timer description");
72	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
73	    "flags", CTLFLAG_RD, &(et->et_flags), 0,
74	    "Event timer capabilities");
75	SYSCTL_ADD_UQUAD(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
76	    "frequency", CTLFLAG_RD, &(et->et_frequency),
77	    "Event timer base frequency");
78	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
79	    "quality", CTLFLAG_RD, &(et->et_quality), 0,
80	    "Goodness of event timer");
81	ET_LOCK();
82	if (SLIST_EMPTY(&eventtimers) ||
83	    SLIST_FIRST(&eventtimers)->et_quality < et->et_quality) {
84		SLIST_INSERT_HEAD(&eventtimers, et, et_all);
85	} else {
86		SLIST_FOREACH(tmp, &eventtimers, et_all) {
87			next = SLIST_NEXT(tmp, et_all);
88			if (next == NULL || next->et_quality < et->et_quality) {
89				SLIST_INSERT_AFTER(tmp, et, et_all);
90				break;
91			}
92		}
93	}
94	ET_UNLOCK();
95	return (0);
96}
97
98/*
99 * Deregister event timer hardware.
100 */
101int
102et_deregister(struct eventtimer *et)
103{
104	int err = 0;
105
106	if (et->et_deregister_cb != NULL) {
107		if ((err = et->et_deregister_cb(et, et->et_arg)) != 0)
108			return (err);
109	}
110
111	ET_LOCK();
112	SLIST_REMOVE(&eventtimers, et, eventtimer, et_all);
113	ET_UNLOCK();
114	sysctl_remove_oid(et->et_sysctl, 1, 1);
115	return (0);
116}
117
118/*
119 * Change the frequency of the given timer.  If it is the active timer,
120 * reconfigure it on all CPUs (reschedules all current events based on the new
121 * timer frequency).
122 */
123void
124et_change_frequency(struct eventtimer *et, uint64_t newfreq)
125{
126
127#ifndef NO_EVENTTIMERS
128	cpu_et_frequency(et, newfreq);
129#endif
130}
131
132/*
133 * Find free event timer hardware with specified parameters.
134 */
135struct eventtimer *
136et_find(const char *name, int check, int want)
137{
138	struct eventtimer *et = NULL;
139
140	SLIST_FOREACH(et, &eventtimers, et_all) {
141		if (et->et_active)
142			continue;
143		if (name != NULL && strcasecmp(et->et_name, name) != 0)
144			continue;
145		if (name == NULL && et->et_quality < 0)
146			continue;
147		if ((et->et_flags & check) != want)
148			continue;
149		break;
150	}
151	return (et);
152}
153
154/*
155 * Initialize event timer hardware. Set callbacks.
156 */
157int
158et_init(struct eventtimer *et, et_event_cb_t *event,
159    et_deregister_cb_t *deregister, void *arg)
160{
161
162	if (event == NULL)
163		return (EINVAL);
164	if (et->et_active)
165		return (EBUSY);
166
167	et->et_active = 1;
168	et->et_event_cb = event;
169	et->et_deregister_cb = deregister;
170	et->et_arg = arg;
171	return (0);
172}
173
174/*
175 * Start event timer hardware.
176 * first - delay before first tick.
177 * period - period of subsequent periodic ticks.
178 */
179int
180et_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
181{
182
183	if (!et->et_active)
184		return (ENXIO);
185	KASSERT(period >= 0, ("et_start: negative period"));
186	KASSERT((et->et_flags & ET_FLAGS_PERIODIC) || period == 0,
187		("et_start: period specified for oneshot-only timer"));
188	KASSERT((et->et_flags & ET_FLAGS_ONESHOT) || period != 0,
189		("et_start: period not specified for periodic-only timer"));
190	if (period != 0) {
191		if (period < et->et_min_period)
192		        period = et->et_min_period;
193		else if (period > et->et_max_period)
194		        period = et->et_max_period;
195	}
196	if (period == 0 || first != 0) {
197		if (first < et->et_min_period)
198		        first = et->et_min_period;
199		else if (first > et->et_max_period)
200		        first = et->et_max_period;
201	}
202	return (et->et_start(et, first, period));
203}
204
205/* Stop event timer hardware. */
206int
207et_stop(struct eventtimer *et)
208{
209
210	if (!et->et_active)
211		return (ENXIO);
212	if (et->et_stop)
213		return (et->et_stop(et));
214	return (0);
215}
216
217/* Mark event timer hardware as broken. */
218int
219et_ban(struct eventtimer *et)
220{
221
222	et->et_flags &= ~(ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT);
223	return (0);
224}
225
226/* Free event timer hardware. */
227int
228et_free(struct eventtimer *et)
229{
230
231	if (!et->et_active)
232		return (ENXIO);
233
234	et->et_active = 0;
235	return (0);
236}
237
238/* Report list of supported event timer hardware via sysctl. */
239static int
240sysctl_kern_eventtimer_choice(SYSCTL_HANDLER_ARGS)
241{
242	struct sbuf sb;
243	struct eventtimer *et;
244	int error;
245
246	sbuf_new(&sb, NULL, 256, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
247
248	ET_LOCK();
249	SLIST_FOREACH(et, &eventtimers, et_all) {
250		if (et != SLIST_FIRST(&eventtimers))
251			sbuf_putc(&sb, ' ');
252		sbuf_printf(&sb, "%s(%d)", et->et_name, et->et_quality);
253	}
254	ET_UNLOCK();
255
256	error = sbuf_finish(&sb);
257	if (error == 0)
258		error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
259	sbuf_delete(&sb);
260	return (error);
261}
262SYSCTL_PROC(_kern_eventtimer, OID_AUTO, choice,
263    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
264    0, 0, sysctl_kern_eventtimer_choice, "A", "Present event timers");
265
266