xref: /freebsd/sys/dev/watchdog/watchdog.c (revision 18242d3b09dbc3f5e278e39baaa3c3b76624c901)
1 /*-
2  * Copyright (c) 2004 Poul-Henning Kamp
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  *    in this position and unchanged.
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 AUTHORS ``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 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/conf.h>
34 #include <sys/uio.h>
35 #include <sys/kernel.h>
36 #include <sys/malloc.h>
37 #include <sys/module.h>
38 #include <sys/watchdog.h>
39 #include <sys/bus.h>
40 #include <machine/bus.h>
41 
42 static struct cdev *wd_dev;
43 
44 static int
45 wd_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t data,
46     int flags __unused, struct thread *td)
47 {
48 	int error;
49 	u_int u;
50 
51 	if (cmd != WDIOCPATPAT)
52 		return (ENOIOCTL);
53 	u = *(u_int *)data;
54 	if (u & ~(WD_ACTIVE | WD_PASSIVE | WD_INTERVAL))
55 		return (EINVAL);
56 	if ((u & (WD_ACTIVE | WD_PASSIVE)) == (WD_ACTIVE | WD_PASSIVE))
57 		return (EINVAL);
58 	if ((u & (WD_ACTIVE | WD_PASSIVE)) == 0 && (u & WD_INTERVAL) > 0)
59 		return (EINVAL);
60 	if (u & WD_PASSIVE)
61 		return (ENOSYS);	/* XXX Not implemented yet */
62 	if ((u & WD_INTERVAL) == WD_TO_NEVER) {
63 		u = 0;
64 		/* Assume all is well; watchdog signals failure. */
65 		error = 0;
66 	} else {
67 		/* Assume no watchdog available; watchdog flags success */
68 		error = EOPNOTSUPP;
69 	}
70 	EVENTHANDLER_INVOKE(watchdog_list, u, &error);
71 	return (error);
72 }
73 
74 static struct cdevsw wd_cdevsw = {
75 	.d_version =	D_VERSION,
76 	.d_ioctl =	wd_ioctl,
77 	.d_name =	"watchdog",
78 };
79 
80 static int
81 watchdog_modevent(module_t mod __unused, int type, void *data __unused)
82 {
83 	switch(type) {
84 	case MOD_LOAD:
85 		wd_dev = make_dev(&wd_cdevsw, 0,
86 		    UID_ROOT, GID_WHEEL, 0600, _PATH_WATCHDOG);
87 		return 0;
88 	case MOD_UNLOAD:
89 		destroy_dev(wd_dev);
90 		return 0;
91 	case MOD_SHUTDOWN:
92 		return 0;
93 	default:
94 		return EOPNOTSUPP;
95 	}
96 }
97 
98 DEV_MODULE(watchdog, watchdog_modevent, NULL);
99