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1da177e4 LT |
1 | /* UML hardware watchdog, shamelessly stolen from: |
2 | * | |
3 | * SoftDog 0.05: A Software Watchdog Device | |
4 | * | |
5 | * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. | |
6 | * http://www.redhat.com | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License | |
10 | * as published by the Free Software Foundation; either version | |
11 | * 2 of the License, or (at your option) any later version. | |
5bbcbeca JD |
12 | * |
13 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide | |
14 | * warranty for any of this software. This material is provided | |
15 | * "AS-IS" and at no charge. | |
1da177e4 LT |
16 | * |
17 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> | |
18 | * | |
19 | * Software only watchdog driver. Unlike its big brother the WDT501P | |
20 | * driver this won't always recover a failed machine. | |
21 | * | |
22 | * 03/96: Angelo Haritsis <ah@doc.ic.ac.uk> : | |
23 | * Modularised. | |
24 | * Added soft_margin; use upon insmod to change the timer delay. | |
25 | * NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate | |
26 | * minors. | |
27 | * | |
28 | * 19980911 Alan Cox | |
29 | * Made SMP safe for 2.3.x | |
30 | * | |
31 | * 20011127 Joel Becker (jlbec@evilplan.org> | |
5bbcbeca | 32 | * Added soft_noboot; Allows testing the softdog trigger without |
1da177e4 LT |
33 | * requiring a recompile. |
34 | * Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT. | |
35 | */ | |
5bbcbeca | 36 | |
1da177e4 | 37 | #include <linux/module.h> |
1da177e4 LT |
38 | #include <linux/types.h> |
39 | #include <linux/kernel.h> | |
40 | #include <linux/fs.h> | |
41 | #include <linux/mm.h> | |
42 | #include <linux/miscdevice.h> | |
43 | #include <linux/watchdog.h> | |
44 | #include <linux/reboot.h> | |
45 | #include <linux/smp_lock.h> | |
46 | #include <linux/init.h> | |
42d36115 | 47 | #include <linux/spinlock.h> |
1da177e4 | 48 | #include <asm/uaccess.h> |
1da177e4 LT |
49 | #include "mconsole.h" |
50 | ||
51 | MODULE_LICENSE("GPL"); | |
52 | ||
42d36115 | 53 | static DEFINE_SPINLOCK(lock); |
1da177e4 LT |
54 | static int timer_alive; |
55 | static int harddog_in_fd = -1; | |
56 | static int harddog_out_fd = -1; | |
57 | ||
58 | /* | |
59 | * Allow only one person to hold it open | |
60 | */ | |
5bbcbeca | 61 | |
1da177e4 LT |
62 | extern int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock); |
63 | ||
64 | static int harddog_open(struct inode *inode, struct file *file) | |
65 | { | |
42d36115 | 66 | int err = -EBUSY; |
1da177e4 LT |
67 | char *sock = NULL; |
68 | ||
42d36115 | 69 | spin_lock(&lock); |
1da177e4 | 70 | if(timer_alive) |
42d36115 | 71 | goto err; |
8d820760 | 72 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
1da177e4 LT |
73 | __module_get(THIS_MODULE); |
74 | #endif | |
75 | ||
76 | #ifdef CONFIG_MCONSOLE | |
77 | sock = mconsole_notify_socket(); | |
78 | #endif | |
79 | err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock); | |
42d36115 JD |
80 | if(err) |
81 | goto err; | |
1da177e4 LT |
82 | |
83 | timer_alive = 1; | |
42d36115 | 84 | spin_unlock(&lock); |
1da177e4 | 85 | return nonseekable_open(inode, file); |
42d36115 JD |
86 | err: |
87 | spin_unlock(&lock); | |
88 | return err; | |
1da177e4 LT |
89 | } |
90 | ||
91 | extern void stop_watchdog(int in_fd, int out_fd); | |
92 | ||
93 | static int harddog_release(struct inode *inode, struct file *file) | |
94 | { | |
95 | /* | |
96 | * Shut off the timer. | |
97 | */ | |
42d36115 JD |
98 | |
99 | spin_lock(&lock); | |
1da177e4 LT |
100 | |
101 | stop_watchdog(harddog_in_fd, harddog_out_fd); | |
102 | harddog_in_fd = -1; | |
103 | harddog_out_fd = -1; | |
104 | ||
105 | timer_alive=0; | |
42d36115 JD |
106 | spin_unlock(&lock); |
107 | ||
1da177e4 LT |
108 | return 0; |
109 | } | |
110 | ||
111 | extern int ping_watchdog(int fd); | |
112 | ||
4d338e1a | 113 | static ssize_t harddog_write(struct file *file, const char __user *data, size_t len, |
1da177e4 LT |
114 | loff_t *ppos) |
115 | { | |
116 | /* | |
117 | * Refresh the timer. | |
118 | */ | |
119 | if(len) | |
5bbcbeca | 120 | return ping_watchdog(harddog_out_fd); |
1da177e4 LT |
121 | return 0; |
122 | } | |
123 | ||
124 | static int harddog_ioctl(struct inode *inode, struct file *file, | |
125 | unsigned int cmd, unsigned long arg) | |
126 | { | |
4d338e1a | 127 | void __user *argp= (void __user *)arg; |
1da177e4 LT |
128 | static struct watchdog_info ident = { |
129 | WDIOC_SETTIMEOUT, | |
130 | 0, | |
131 | "UML Hardware Watchdog" | |
132 | }; | |
133 | switch (cmd) { | |
134 | default: | |
135 | return -ENOTTY; | |
136 | case WDIOC_GETSUPPORT: | |
4d338e1a | 137 | if(copy_to_user(argp, &ident, sizeof(ident))) |
1da177e4 LT |
138 | return -EFAULT; |
139 | return 0; | |
140 | case WDIOC_GETSTATUS: | |
141 | case WDIOC_GETBOOTSTATUS: | |
4d338e1a | 142 | return put_user(0,(int __user *)argp); |
1da177e4 | 143 | case WDIOC_KEEPALIVE: |
5bbcbeca | 144 | return ping_watchdog(harddog_out_fd); |
1da177e4 LT |
145 | } |
146 | } | |
147 | ||
5dfe4c96 | 148 | static const struct file_operations harddog_fops = { |
1da177e4 LT |
149 | .owner = THIS_MODULE, |
150 | .write = harddog_write, | |
151 | .ioctl = harddog_ioctl, | |
152 | .open = harddog_open, | |
153 | .release = harddog_release, | |
154 | }; | |
155 | ||
156 | static struct miscdevice harddog_miscdev = { | |
157 | .minor = WATCHDOG_MINOR, | |
158 | .name = "watchdog", | |
159 | .fops = &harddog_fops, | |
160 | }; | |
161 | ||
162 | static char banner[] __initdata = KERN_INFO "UML Watchdog Timer\n"; | |
163 | ||
164 | static int __init harddog_init(void) | |
165 | { | |
166 | int ret; | |
167 | ||
168 | ret = misc_register(&harddog_miscdev); | |
169 | ||
170 | if (ret) | |
171 | return ret; | |
172 | ||
173 | printk(banner); | |
174 | ||
5bbcbeca | 175 | return 0; |
1da177e4 LT |
176 | } |
177 | ||
178 | static void __exit harddog_exit(void) | |
179 | { | |
180 | misc_deregister(&harddog_miscdev); | |
181 | } | |
182 | ||
183 | module_init(harddog_init); | |
184 | module_exit(harddog_exit); |