Commit | Line | Data |
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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> | |
9a181c58 | 45 | #include <linux/mutex.h> |
1da177e4 | 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 | ||
9a181c58 | 53 | static DEFINE_MUTEX(harddog_mutex); |
42d36115 | 54 | static DEFINE_SPINLOCK(lock); |
1da177e4 LT |
55 | static int timer_alive; |
56 | static int harddog_in_fd = -1; | |
57 | static int harddog_out_fd = -1; | |
58 | ||
59 | /* | |
60 | * Allow only one person to hold it open | |
61 | */ | |
5bbcbeca | 62 | |
1da177e4 LT |
63 | extern int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock); |
64 | ||
65 | static int harddog_open(struct inode *inode, struct file *file) | |
66 | { | |
42d36115 | 67 | int err = -EBUSY; |
1da177e4 LT |
68 | char *sock = NULL; |
69 | ||
9a181c58 | 70 | mutex_lock(&harddog_mutex); |
42d36115 | 71 | spin_lock(&lock); |
1da177e4 | 72 | if(timer_alive) |
42d36115 | 73 | goto err; |
8d820760 | 74 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
1da177e4 LT |
75 | __module_get(THIS_MODULE); |
76 | #endif | |
77 | ||
78 | #ifdef CONFIG_MCONSOLE | |
79 | sock = mconsole_notify_socket(); | |
80 | #endif | |
81 | err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock); | |
42d36115 JD |
82 | if(err) |
83 | goto err; | |
1da177e4 LT |
84 | |
85 | timer_alive = 1; | |
42d36115 | 86 | spin_unlock(&lock); |
9a181c58 | 87 | mutex_unlock(&harddog_mutex); |
1da177e4 | 88 | return nonseekable_open(inode, file); |
42d36115 JD |
89 | err: |
90 | spin_unlock(&lock); | |
9a181c58 | 91 | mutex_unlock(&harddog_mutex); |
42d36115 | 92 | return err; |
1da177e4 LT |
93 | } |
94 | ||
95 | extern void stop_watchdog(int in_fd, int out_fd); | |
96 | ||
97 | static int harddog_release(struct inode *inode, struct file *file) | |
98 | { | |
99 | /* | |
100 | * Shut off the timer. | |
101 | */ | |
42d36115 JD |
102 | |
103 | spin_lock(&lock); | |
1da177e4 LT |
104 | |
105 | stop_watchdog(harddog_in_fd, harddog_out_fd); | |
106 | harddog_in_fd = -1; | |
107 | harddog_out_fd = -1; | |
108 | ||
109 | timer_alive=0; | |
42d36115 JD |
110 | spin_unlock(&lock); |
111 | ||
1da177e4 LT |
112 | return 0; |
113 | } | |
114 | ||
115 | extern int ping_watchdog(int fd); | |
116 | ||
4d338e1a | 117 | static ssize_t harddog_write(struct file *file, const char __user *data, size_t len, |
1da177e4 LT |
118 | loff_t *ppos) |
119 | { | |
120 | /* | |
121 | * Refresh the timer. | |
122 | */ | |
123 | if(len) | |
5bbcbeca | 124 | return ping_watchdog(harddog_out_fd); |
1da177e4 LT |
125 | return 0; |
126 | } | |
127 | ||
9f37af65 FW |
128 | static int harddog_ioctl_unlocked(struct file *file, |
129 | unsigned int cmd, unsigned long arg) | |
1da177e4 | 130 | { |
4d338e1a | 131 | void __user *argp= (void __user *)arg; |
1da177e4 LT |
132 | static struct watchdog_info ident = { |
133 | WDIOC_SETTIMEOUT, | |
134 | 0, | |
135 | "UML Hardware Watchdog" | |
136 | }; | |
137 | switch (cmd) { | |
138 | default: | |
139 | return -ENOTTY; | |
140 | case WDIOC_GETSUPPORT: | |
4d338e1a | 141 | if(copy_to_user(argp, &ident, sizeof(ident))) |
1da177e4 LT |
142 | return -EFAULT; |
143 | return 0; | |
144 | case WDIOC_GETSTATUS: | |
145 | case WDIOC_GETBOOTSTATUS: | |
4d338e1a | 146 | return put_user(0,(int __user *)argp); |
1da177e4 | 147 | case WDIOC_KEEPALIVE: |
5bbcbeca | 148 | return ping_watchdog(harddog_out_fd); |
1da177e4 LT |
149 | } |
150 | } | |
151 | ||
9f37af65 FW |
152 | static long harddog_ioctl(struct file *file, |
153 | unsigned int cmd, unsigned long arg) | |
154 | { | |
155 | long ret; | |
156 | ||
9a181c58 | 157 | mutex_lock(&harddog_mutex); |
9f37af65 | 158 | ret = harddog_ioctl_unlocked(file, cmd, arg); |
9a181c58 | 159 | mutex_unlock(&harddog_mutex); |
9f37af65 FW |
160 | |
161 | return ret; | |
162 | } | |
163 | ||
5dfe4c96 | 164 | static const struct file_operations harddog_fops = { |
1da177e4 LT |
165 | .owner = THIS_MODULE, |
166 | .write = harddog_write, | |
9f37af65 | 167 | .unlocked_ioctl = harddog_ioctl, |
1da177e4 LT |
168 | .open = harddog_open, |
169 | .release = harddog_release, | |
6038f373 | 170 | .llseek = no_llseek, |
1da177e4 LT |
171 | }; |
172 | ||
173 | static struct miscdevice harddog_miscdev = { | |
174 | .minor = WATCHDOG_MINOR, | |
175 | .name = "watchdog", | |
176 | .fops = &harddog_fops, | |
177 | }; | |
178 | ||
179 | static char banner[] __initdata = KERN_INFO "UML Watchdog Timer\n"; | |
180 | ||
181 | static int __init harddog_init(void) | |
182 | { | |
183 | int ret; | |
184 | ||
185 | ret = misc_register(&harddog_miscdev); | |
186 | ||
187 | if (ret) | |
188 | return ret; | |
189 | ||
190 | printk(banner); | |
191 | ||
5bbcbeca | 192 | return 0; |
1da177e4 LT |
193 | } |
194 | ||
195 | static void __exit harddog_exit(void) | |
196 | { | |
197 | misc_deregister(&harddog_miscdev); | |
198 | } | |
199 | ||
200 | module_init(harddog_init); | |
201 | module_exit(harddog_exit); |