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
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 | CTLFLAG_MPSAFE, 0,
47    "Event timers");
48static SYSCTL_NODE(_kern_eventtimer, OID_AUTO, et,
49    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
50    "");
51
52/*
53 * Register a new event timer hardware.
54 */
55int
56et_register(struct eventtimer *et)
57{
58	struct eventtimer *tmp, *next;
59
60	if (et->et_quality >= 0 || bootverbose) {
61		if (et->et_frequency == 0) {
62			printf("Event timer \"%s\" quality %d\n",
63			    et->et_name, et->et_quality);
64		} else {
65			printf("Event timer \"%s\" "
66			    "frequency %ju Hz quality %d\n",
67			    et->et_name, (uintmax_t)et->et_frequency,
68			    et->et_quality);
69		}
70	}
71	KASSERT(et->et_start, ("et_register: timer has no start function"));
72	et->et_sysctl = SYSCTL_ADD_NODE_WITH_LABEL(NULL,
73	    SYSCTL_STATIC_CHILDREN(_kern_eventtimer_et), OID_AUTO, et->et_name,
74	    CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
75	    "event timer description", "eventtimer");
76	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
77	    "flags", CTLFLAG_RD, &(et->et_flags), 0,
78	    "Event timer capabilities");
79	SYSCTL_ADD_UQUAD(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
80	    "frequency", CTLFLAG_RD, &(et->et_frequency),
81	    "Event timer base frequency");
82	SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
83	    "quality", CTLFLAG_RD, &(et->et_quality), 0,
84	    "Goodness of event timer");
85	ET_LOCK();
86	if (SLIST_EMPTY(&eventtimers) ||
87	    SLIST_FIRST(&eventtimers)->et_quality < et->et_quality) {
88		SLIST_INSERT_HEAD(&eventtimers, et, et_all);
89	} else {
90		SLIST_FOREACH(tmp, &eventtimers, et_all) {
91			next = SLIST_NEXT(tmp, et_all);
92			if (next == NULL || next->et_quality < et->et_quality) {
93				SLIST_INSERT_AFTER(tmp, et, et_all);
94				break;
95			}
96		}
97	}
98	ET_UNLOCK();
99	return (0);
100}
101
102/*
103 * Deregister event timer hardware.
104 */
105int
106et_deregister(struct eventtimer *et)
107{
108	int err = 0;
109
110	if (et->et_deregister_cb != NULL) {
111		if ((err = et->et_deregister_cb(et, et->et_arg)) != 0)
112			return (err);
113	}
114
115	ET_LOCK();
116	SLIST_REMOVE(&eventtimers, et, eventtimer, et_all);
117	ET_UNLOCK();
118	sysctl_remove_oid(et->et_sysctl, 1, 1);
119	return (0);
120}
121
122/*
123 * Change the frequency of the given timer.  If it is the active timer,
124 * reconfigure it on all CPUs (reschedules all current events based on the new
125 * timer frequency).
126 */
127void
128et_change_frequency(struct eventtimer *et, uint64_t newfreq)
129{
130
131	cpu_et_frequency(et, newfreq);
132}
133
134/*
135 * Find free event timer hardware with specified parameters.
136 */
137struct eventtimer *
138et_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 */
159int
160et_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 */
181int
182et_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. */
208int
209et_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. */
220int
221et_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. */
229int
230et_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. */
241static int
242sysctl_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}
264SYSCTL_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