1 /*
2 * IndyDog 0.3 A Hardware Watchdog Device for SGI IP22
3 *
4 * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>,
5 * All Rights Reserved.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
13 */
14
15 #include <linux/module.h>
16 #include <linux/moduleparam.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 <linux/uaccess.h>
27 #include <asm/sgi/mc.h>
28
29 #define PFX "indydog: "
30 static unsigned long indydog_alive;
31 static spinlock_t indydog_lock;
32
33 #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
34
35 static int nowayout = WATCHDOG_NOWAYOUT;
36 module_param(nowayout, int, 0);
37 MODULE_PARM_DESC(nowayout,
38 "Watchdog cannot be stopped once started (default="
39 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
40
41 static void indydog_start(void)
42 {
43 u32 mc_ctrl0;
44
45 spin_lock(&indydog_lock);
46 mc_ctrl0 = sgimc->cpuctrl0;
47 mc_ctrl0 = sgimc->cpuctrl0 | SGIMC_CCTRL0_WDOG;
48 sgimc->cpuctrl0 = mc_ctrl0;
49 spin_unlock(&indydog_lock);
50 }
51
52 static void indydog_stop(void)
53 {
54 u32 mc_ctrl0;
55
56 spin_lock(&indydog_lock);
57
58 mc_ctrl0 = sgimc->cpuctrl0;
59 mc_ctrl0 &= ~SGIMC_CCTRL0_WDOG;
60 sgimc->cpuctrl0 = mc_ctrl0;
61 spin_unlock(&indydog_lock);
62
63 printk(KERN_INFO PFX "Stopped watchdog timer.\n");
64 }
65
66 static void indydog_ping(void)
67 {
68 sgimc->watchdogt = 0;
69 }
70
71 /*
72 * Allow only one person to hold it open
73 */
74 static int indydog_open(struct inode *inode, struct file *file)
75 {
76 if (test_and_set_bit(0, &indydog_alive))
77 return -EBUSY;
78
79 if (nowayout)
80 __module_get(THIS_MODULE);
81
82 /* Activate timer */
83 indydog_start();
84 indydog_ping();
85
86 printk(KERN_INFO "Started watchdog timer.\n");
87
88 return nonseekable_open(inode, file);
89 }
90
91 static int indydog_release(struct inode *inode, struct file *file)
92 {
93 /* Shut off the timer.
94 * Lock it in if it's a module and we defined ...NOWAYOUT */
95 if (!nowayout)
96 indydog_stop(); /* Turn the WDT off */
97 clear_bit(0, &indydog_alive);
98 return 0;
99 }
100
101 static ssize_t indydog_write(struct file *file, const char *data,
102 size_t len, loff_t *ppos)
103 {
104 /* Refresh the timer. */
105 if (len)
106 indydog_ping();
107 return len;
108 }
109
110 static long indydog_ioctl(struct file *file, unsigned int cmd,
111 unsigned long arg)
112 {
113 int options, retval = -EINVAL;
114 static struct watchdog_info ident = {
115 .options = WDIOF_KEEPALIVEPING,
116 .firmware_version = 0,
117 .identity = "Hardware Watchdog for SGI IP22",
118 };
119
120 switch (cmd) {
121 case WDIOC_GETSUPPORT:
122 if (copy_to_user((struct watchdog_info *)arg,
123 &ident, sizeof(ident)))
124 return -EFAULT;
125 return 0;
126 case WDIOC_GETSTATUS:
127 case WDIOC_GETBOOTSTATUS:
128 return put_user(0, (int *)arg);
129 case WDIOC_SETOPTIONS:
130 {
131 if (get_user(options, (int *)arg))
132 return -EFAULT;
133 if (options & WDIOS_DISABLECARD) {
134 indydog_stop();
135 retval = 0;
136 }
137 if (options & WDIOS_ENABLECARD) {
138 indydog_start();
139 retval = 0;
140 }
141 return retval;
142 }
143 case WDIOC_KEEPALIVE:
144 indydog_ping();
145 return 0;
146 case WDIOC_GETTIMEOUT:
147 return put_user(WATCHDOG_TIMEOUT, (int *)arg);
148 default:
149 return -ENOTTY;
150 }
151 }
152
153 static int indydog_notify_sys(struct notifier_block *this,
154 unsigned long code, void *unused)
155 {
156 if (code == SYS_DOWN || code == SYS_HALT)
157 indydog_stop(); /* Turn the WDT off */
158
159 return NOTIFY_DONE;
160 }
161
162 static const struct file_operations indydog_fops = {
163 .owner = THIS_MODULE,
164 .llseek = no_llseek,
165 .write = indydog_write,
166 .unlocked_ioctl = indydog_ioctl,
167 .open = indydog_open,
168 .release = indydog_release,
169 };
170
171 static struct miscdevice indydog_miscdev = {
172 .minor = WATCHDOG_MINOR,
173 .name = "watchdog",
174 .fops = &indydog_fops,
175 };
176
177 static struct notifier_block indydog_notifier = {
178 .notifier_call = indydog_notify_sys,
179 };
180
181 static char banner[] __initdata =
182 KERN_INFO PFX "Hardware Watchdog Timer for SGI IP22: 0.3\n";
183
184 static int __init watchdog_init(void)
185 {
186 int ret;
187
188 spin_lock_init(&indydog_lock);
189
190 ret = register_reboot_notifier(&indydog_notifier);
191 if (ret) {
192 printk(KERN_ERR PFX
193 "cannot register reboot notifier (err=%d)\n", ret);
194 return ret;
195 }
196
197 ret = misc_register(&indydog_miscdev);
198 if (ret) {
199 printk(KERN_ERR PFX
200 "cannot register miscdev on minor=%d (err=%d)\n",
201 WATCHDOG_MINOR, ret);
202 unregister_reboot_notifier(&indydog_notifier);
203 return ret;
204 }
205
206 printk(banner);
207
208 return 0;
209 }
210
211 static void __exit watchdog_exit(void)
212 {
213 misc_deregister(&indydog_miscdev);
214 unregister_reboot_notifier(&indydog_notifier);
215 }
216
217 module_init(watchdog_init);
218 module_exit(watchdog_exit);
219
220 MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>");
221 MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22");
222 MODULE_LICENSE("GPL");
223 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
224
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