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15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include <linux/module.h>
18#include <linux/moduleparam.h>
19#include <linux/types.h>
20#include <linux/kernel.h>
21#include <linux/fs.h>
22#include <linux/mm.h>
23#include <linux/miscdevice.h>
24#include <linux/watchdog.h>
25#include <linux/notifier.h>
26#include <linux/reboot.h>
27#include <linux/init.h>
28#include <linux/uaccess.h>
29#include <asm/sgi/mc.h>
30
31static unsigned long indydog_alive;
32static DEFINE_SPINLOCK(indydog_lock);
33
34#define WATCHDOG_TIMEOUT 30
35
36static bool nowayout = WATCHDOG_NOWAYOUT;
37module_param(nowayout, bool, 0);
38MODULE_PARM_DESC(nowayout,
39 "Watchdog cannot be stopped once started (default="
40 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
41
42static void indydog_start(void)
43{
44 spin_lock(&indydog_lock);
45 sgimc->cpuctrl0 |= SGIMC_CCTRL0_WDOG;
46 spin_unlock(&indydog_lock);
47}
48
49static void indydog_stop(void)
50{
51 spin_lock(&indydog_lock);
52 sgimc->cpuctrl0 &= ~SGIMC_CCTRL0_WDOG;
53 spin_unlock(&indydog_lock);
54
55 pr_info("Stopped watchdog timer\n");
56}
57
58static void indydog_ping(void)
59{
60 sgimc->watchdogt = 0;
61}
62
63
64
65
66static int indydog_open(struct inode *inode, struct file *file)
67{
68 if (test_and_set_bit(0, &indydog_alive))
69 return -EBUSY;
70
71 if (nowayout)
72 __module_get(THIS_MODULE);
73
74
75 indydog_start();
76 indydog_ping();
77
78 pr_info("Started watchdog timer\n");
79
80 return nonseekable_open(inode, file);
81}
82
83static int indydog_release(struct inode *inode, struct file *file)
84{
85
86
87 if (!nowayout)
88 indydog_stop();
89 clear_bit(0, &indydog_alive);
90 return 0;
91}
92
93static ssize_t indydog_write(struct file *file, const char *data,
94 size_t len, loff_t *ppos)
95{
96
97 if (len)
98 indydog_ping();
99 return len;
100}
101
102static long indydog_ioctl(struct file *file, unsigned int cmd,
103 unsigned long arg)
104{
105 int options, retval = -EINVAL;
106 static const struct watchdog_info ident = {
107 .options = WDIOF_KEEPALIVEPING,
108 .firmware_version = 0,
109 .identity = "Hardware Watchdog for SGI IP22",
110 };
111
112 switch (cmd) {
113 case WDIOC_GETSUPPORT:
114 if (copy_to_user((struct watchdog_info *)arg,
115 &ident, sizeof(ident)))
116 return -EFAULT;
117 return 0;
118 case WDIOC_GETSTATUS:
119 case WDIOC_GETBOOTSTATUS:
120 return put_user(0, (int *)arg);
121 case WDIOC_SETOPTIONS:
122 {
123 if (get_user(options, (int *)arg))
124 return -EFAULT;
125 if (options & WDIOS_DISABLECARD) {
126 indydog_stop();
127 retval = 0;
128 }
129 if (options & WDIOS_ENABLECARD) {
130 indydog_start();
131 retval = 0;
132 }
133 return retval;
134 }
135 case WDIOC_KEEPALIVE:
136 indydog_ping();
137 return 0;
138 case WDIOC_GETTIMEOUT:
139 return put_user(WATCHDOG_TIMEOUT, (int *)arg);
140 default:
141 return -ENOTTY;
142 }
143}
144
145static int indydog_notify_sys(struct notifier_block *this,
146 unsigned long code, void *unused)
147{
148 if (code == SYS_DOWN || code == SYS_HALT)
149 indydog_stop();
150
151 return NOTIFY_DONE;
152}
153
154static const struct file_operations indydog_fops = {
155 .owner = THIS_MODULE,
156 .llseek = no_llseek,
157 .write = indydog_write,
158 .unlocked_ioctl = indydog_ioctl,
159 .open = indydog_open,
160 .release = indydog_release,
161};
162
163static struct miscdevice indydog_miscdev = {
164 .minor = WATCHDOG_MINOR,
165 .name = "watchdog",
166 .fops = &indydog_fops,
167};
168
169static struct notifier_block indydog_notifier = {
170 .notifier_call = indydog_notify_sys,
171};
172
173static int __init watchdog_init(void)
174{
175 int ret;
176
177 ret = register_reboot_notifier(&indydog_notifier);
178 if (ret) {
179 pr_err("cannot register reboot notifier (err=%d)\n", ret);
180 return ret;
181 }
182
183 ret = misc_register(&indydog_miscdev);
184 if (ret) {
185 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
186 WATCHDOG_MINOR, ret);
187 unregister_reboot_notifier(&indydog_notifier);
188 return ret;
189 }
190
191 pr_info("Hardware Watchdog Timer for SGI IP22: 0.3\n");
192
193 return 0;
194}
195
196static void __exit watchdog_exit(void)
197{
198 misc_deregister(&indydog_miscdev);
199 unregister_reboot_notifier(&indydog_notifier);
200}
201
202module_init(watchdog_init);
203module_exit(watchdog_exit);
204
205MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>");
206MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22");
207MODULE_LICENSE("GPL");
208
