1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
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/param.h>
30#include <sys/kernel.h>
31#include <sys/sbuf.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_DEF);
42
43SYSCTL_NODE(_kern, OID_AUTO, eventtimer, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
44    "Event timers");
45static SYSCTL_NODE(_kern_eventtimer, OID_AUTO, et,
46    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
47    "");
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_WITH_LABEL(NULL,
70	    SYSCTL_STATIC_CHILDREN(_kern_eventtimer_et), OID_AUTO, et->et_name,
71	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
72	    "event timer description", "eventtimer");
73	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
74	    "flags", CTLFLAG_RD, &(et->et_flags), 0,
75	    "Event timer capabilities");
76	SYSCTL_ADD_UQUAD(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
77	    "frequency", CTLFLAG_RD, &(et->et_frequency),
78	    "Event timer base frequency");
79	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
80	    "quality", CTLFLAG_RD, &(et->et_quality), 0,
81	    "Goodness of event timer");
82	ET_LOCK();
83	if (SLIST_EMPTY(&eventtimers) ||
84	    SLIST_FIRST(&eventtimers)->et_quality < et->et_quality) {
85		SLIST_INSERT_HEAD(&eventtimers, et, et_all);
86	} else {
87		SLIST_FOREACH(tmp, &eventtimers, et_all) {
88			next = SLIST_NEXT(tmp, et_all);
89			if (next == NULL || next->et_quality < et->et_quality) {
90				SLIST_INSERT_AFTER(tmp, et, et_all);
91				break;
92			}
93		}
94	}
95	ET_UNLOCK();
96	return (0);
97}
98
99/*
100 * Deregister event timer hardware.
101 */
102int
103et_deregister(struct eventtimer *et)
104{
105	int err = 0;
106
107	if (et->et_deregister_cb != NULL) {
108		if ((err = et->et_deregister_cb(et, et->et_arg)) != 0)
109			return (err);
110	}
111
112	ET_LOCK();
113	SLIST_REMOVE(&eventtimers, et, eventtimer, et_all);
114	ET_UNLOCK();
115	sysctl_remove_oid(et->et_sysctl, 1, 1);
116	return (0);
117}
118
119/*
120 * Change the frequency of the given timer.  If it is the active timer,
121 * reconfigure it on all CPUs (reschedules all current events based on the new
122 * timer frequency).
123 */
124void
125et_change_frequency(struct eventtimer *et, uint64_t newfreq)
126{
127
128	cpu_et_frequency(et, newfreq);
129}
130
131/*
132 * Find free event timer hardware with specified parameters.
133 */
134struct eventtimer *
135et_find(const char *name, int check, int want)
136{
137	struct eventtimer *et = NULL;
138
139	SLIST_FOREACH(et, &eventtimers, et_all) {
140		if (et->et_active)
141			continue;
142		if (name != NULL && strcasecmp(et->et_name, name) != 0)
143			continue;
144		if (name == NULL && et->et_quality < 0)
145			continue;
146		if ((et->et_flags & check) != want)
147			continue;
148		break;
149	}
150	return (et);
151}
152
153/*
154 * Initialize event timer hardware. Set callbacks.
155 */
156int
157et_init(struct eventtimer *et, et_event_cb_t *event,
158    et_deregister_cb_t *deregister, void *arg)
159{
160
161	if (event == NULL)
162		return (EINVAL);
163	if (et->et_active)
164		return (EBUSY);
165
166	et->et_active = 1;
167	et->et_event_cb = event;
168	et->et_deregister_cb = deregister;
169	et->et_arg = arg;
170	return (0);
171}
172
173/*
174 * Start event timer hardware.
175 * first - delay before first tick.
176 * period - period of subsequent periodic ticks.
177 */
178int
179et_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
180{
181
182	if (!et->et_active)
183		return (ENXIO);
184	KASSERT(period >= 0, ("et_start: negative period"));
185	KASSERT((et->et_flags & ET_FLAGS_PERIODIC) || period == 0,
186		("et_start: period specified for oneshot-only timer"));
187	KASSERT((et->et_flags & ET_FLAGS_ONESHOT) || period != 0,
188		("et_start: period not specified for periodic-only timer"));
189	if (period != 0) {
190		if (period < et->et_min_period)
191		        period = et->et_min_period;
192		else if (period > et->et_max_period)
193		        period = et->et_max_period;
194	}
195	if (period == 0 || first != 0) {
196		if (first < et->et_min_period)
197		        first = et->et_min_period;
198		else if (first > et->et_max_period)
199		        first = et->et_max_period;
200	}
201	return (et->et_start(et, first, period));
202}
203
204/* Stop event timer hardware. */
205int
206et_stop(struct eventtimer *et)
207{
208
209	if (!et->et_active)
210		return (ENXIO);
211	if (et->et_stop)
212		return (et->et_stop(et));
213	return (0);
214}
215
216/* Mark event timer hardware as broken. */
217int
218et_ban(struct eventtimer *et)
219{
220
221	et->et_flags &= ~(ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT);
222	return (0);
223}
224
225/* Free event timer hardware. */
226int
227et_free(struct eventtimer *et)
228{
229
230	if (!et->et_active)
231		return (ENXIO);
232
233	et->et_active = 0;
234	return (0);
235}
236
237/* Report list of supported event timer hardware via sysctl. */
238static int
239sysctl_kern_eventtimer_choice(SYSCTL_HANDLER_ARGS)
240{
241	struct sbuf sb;
242	struct eventtimer *et;
243	int error;
244
245	sbuf_new(&sb, NULL, 256, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
246
247	ET_LOCK();
248	SLIST_FOREACH(et, &eventtimers, et_all) {
249		if (et != SLIST_FIRST(&eventtimers))
250			sbuf_putc(&sb, ' ');
251		sbuf_printf(&sb, "%s(%d)", et->et_name, et->et_quality);
252	}
253	ET_UNLOCK();
254
255	error = sbuf_finish(&sb);
256	if (error == 0)
257		error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
258	sbuf_delete(&sb);
259	return (error);
260}
261SYSCTL_PROC(_kern_eventtimer, OID_AUTO, choice,
262    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
263    0, 0, sysctl_kern_eventtimer_choice, "A", "Present event timers");
264