1 /*
2 * IndyDog 0.3 A Hardware Watchdog Device for SGI IP22
3 *
4 * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, All Rights Reserved.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * based on softdog.c by Alan Cox <alan@redhat.com>
12 */
13
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/config.h>
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/fs.h>
20 #include <linux/mm.h>
21 #include <linux/miscdevice.h>
22 #include <linux/watchdog.h>
23 #include <linux/notifier.h>
24 #include <linux/reboot.h>
25 #include <linux/init.h>
26 #include <asm/uaccess.h>
27 #include <asm/sgi/mc.h>
28
29 #define PFX "indydog: "
30 static int indydog_alive;
31
32 #ifdef CONFIG_WATCHDOG_NOWAYOUT
33 static int nowayout = 1;
34 #else
35 static int nowayout = 0;
36 #endif
37
38 #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
39
40 module_param(nowayout, int, 0);
41 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
42
43 static void indydog_start(void)
44 {
45 u32 mc_ctrl0 = sgimc->cpuctrl0;
46
47 mc_ctrl0 = sgimc->cpuctrl0 | SGIMC_CCTRL0_WDOG;
48 sgimc->cpuctrl0 = mc_ctrl0;
49 }
50
51 static void indydog_stop(void)
52 {
53 u32 mc_ctrl0 = sgimc->cpuctrl0;
54
55 mc_ctrl0 &= ~SGIMC_CCTRL0_WDOG;
56 sgimc->cpuctrl0 = mc_ctrl0;
57
58 printk(KERN_INFO PFX "Stopped watchdog timer.\n");
59 }
60
61 static void indydog_ping(void)
62 {
63 sgimc->watchdogt = 0;
64 }
65
66 /*
67 * Allow only one person to hold it open
68 */
69 static int indydog_open(struct inode *inode, struct file *file)
70 {
71 if (indydog_alive)
72 return -EBUSY;
73
74 if (nowayout)
75 __module_get(THIS_MODULE);
76
77 /* Activate timer */
78 indydog_start();
79 indydog_ping();
80
81 indydog_alive = 1;
82 printk(KERN_INFO "Started watchdog timer.\n");
83
84 return nonseekable_open(inode, file);
85 }
86
87 static int indydog_release(struct inode *inode, struct file *file)
88 {
89 /* Shut off the timer.
90 * Lock it in if it's a module and we defined ...NOWAYOUT */
91 if (!nowayout)
92 indydog_stop(); /* Turn the WDT off */
93
94 indydog_alive = 0;
95
96 return 0;
97 }
98
99 static ssize_t indydog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
100 {
101 /* Refresh the timer. */
102 if (len) {
103 indydog_ping();
104 }
105 return len;
106 }
107
108 static int indydog_ioctl(struct inode *inode, struct file *file,
109 unsigned int cmd, unsigned long arg)
110 {
111 int options, retval = -EINVAL;
112 static struct watchdog_info ident = {
113 .options = WDIOF_KEEPALIVEPING |
114 WDIOF_MAGICCLOSE,
115 .firmware_version = 0,
116 .identity = "Hardware Watchdog for SGI IP22",
117 };
118
119 switch (cmd) {
120 default:
121 return -ENOIOCTLCMD;
122 case WDIOC_GETSUPPORT:
123 if (copy_to_user((struct watchdog_info *)arg,
124 &ident, sizeof(ident)))
125 return -EFAULT;
126 return 0;
127 case WDIOC_GETSTATUS:
128 case WDIOC_GETBOOTSTATUS:
129 return put_user(0,(int *)arg);
130 case WDIOC_KEEPALIVE:
131 indydog_ping();
132 return 0;
133 case WDIOC_GETTIMEOUT:
134 return put_user(WATCHDOG_TIMEOUT,(int *)arg);
135 case WDIOC_SETOPTIONS:
136 {
137 if (get_user(options, (int *)arg))
138 return -EFAULT;
139
140 if (options & WDIOS_DISABLECARD) {
141 indydog_stop();
142 retval = 0;
143 }
144
145 if (options & WDIOS_ENABLECARD) {
146 indydog_start();
147 retval = 0;
148 }
149
150 return retval;
151 }
152 }
153 }
154
155 static int indydog_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
156 {
157 if (code == SYS_DOWN || code == SYS_HALT)
158 indydog_stop(); /* Turn the WDT off */
159
160 return NOTIFY_DONE;
161 }
162
163 static struct file_operations indydog_fops = {
164 .owner = THIS_MODULE,
165 .llseek = no_llseek,
166 .write = indydog_write,
167 .ioctl = indydog_ioctl,
168 .open = indydog_open,
169 .release = indydog_release,
170 };
171
172 static struct miscdevice indydog_miscdev = {
173 .minor = WATCHDOG_MINOR,
174 .name = "watchdog",
175 .fops = &indydog_fops,
176 };
177
178 static struct notifier_block indydog_notifier = {
179 .notifier_call = indydog_notify_sys,
180 };
181
182 static char banner[] __initdata =
183 KERN_INFO PFX "Hardware Watchdog Timer for SGI IP22: 0.3\n";
184
185 static int __init watchdog_init(void)
186 {
187 int ret;
188
189 ret = register_reboot_notifier(&indydog_notifier);
190 if (ret) {
191 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
192 ret);
193 return ret;
194 }
195
196 ret = misc_register(&indydog_miscdev);
197 if (ret) {
198 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
199 WATCHDOG_MINOR, ret);
200 unregister_reboot_notifier(&indydog_notifier);
201 return ret;
202 }
203
204 printk(banner);
205
206 return 0;
207 }
208
209 static void __exit watchdog_exit(void)
210 {
211 misc_deregister(&indydog_miscdev);
212 unregister_reboot_notifier(&indydog_notifier);
213 }
214
215 module_init(watchdog_init);
216 module_exit(watchdog_exit);
217
218 MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>");
219 MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22");
220 MODULE_LICENSE("GPL");
221 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
222
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