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11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/fs.h>
18#include <linux/mm.h>
19#include <linux/miscdevice.h>
20#include <linux/watchdog.h>
21#include <linux/notifier.h>
22#include <linux/reboot.h>
23#include <linux/init.h>
24#include <linux/uaccess.h>
25#include <asm/sgi/mc.h>
26
27static unsigned long indydog_alive;
28static DEFINE_SPINLOCK(indydog_lock);
29
30#define WATCHDOG_TIMEOUT 30
31
32static bool nowayout = WATCHDOG_NOWAYOUT;
33module_param(nowayout, bool, 0);
34MODULE_PARM_DESC(nowayout,
35 "Watchdog cannot be stopped once started (default="
36 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
37
38static void indydog_start(void)
39{
40 spin_lock(&indydog_lock);
41 sgimc->cpuctrl0 |= SGIMC_CCTRL0_WDOG;
42 spin_unlock(&indydog_lock);
43}
44
45static void indydog_stop(void)
46{
47 spin_lock(&indydog_lock);
48 sgimc->cpuctrl0 &= ~SGIMC_CCTRL0_WDOG;
49 spin_unlock(&indydog_lock);
50
51 pr_info("Stopped watchdog timer\n");
52}
53
54static void indydog_ping(void)
55{
56 sgimc->watchdogt = 0;
57}
58
59
60
61
62static int indydog_open(struct inode *inode, struct file *file)
63{
64 if (test_and_set_bit(0, &indydog_alive))
65 return -EBUSY;
66
67 if (nowayout)
68 __module_get(THIS_MODULE);
69
70
71 indydog_start();
72 indydog_ping();
73
74 pr_info("Started watchdog timer\n");
75
76 return stream_open(inode, file);
77}
78
79static int indydog_release(struct inode *inode, struct file *file)
80{
81
82
83 if (!nowayout)
84 indydog_stop();
85 clear_bit(0, &indydog_alive);
86 return 0;
87}
88
89static ssize_t indydog_write(struct file *file, const char *data,
90 size_t len, loff_t *ppos)
91{
92
93 if (len)
94 indydog_ping();
95 return len;
96}
97
98static long indydog_ioctl(struct file *file, unsigned int cmd,
99 unsigned long arg)
100{
101 int options, retval = -EINVAL;
102 static const struct watchdog_info ident = {
103 .options = WDIOF_KEEPALIVEPING,
104 .firmware_version = 0,
105 .identity = "Hardware Watchdog for SGI IP22",
106 };
107
108 switch (cmd) {
109 case WDIOC_GETSUPPORT:
110 if (copy_to_user((struct watchdog_info *)arg,
111 &ident, sizeof(ident)))
112 return -EFAULT;
113 return 0;
114 case WDIOC_GETSTATUS:
115 case WDIOC_GETBOOTSTATUS:
116 return put_user(0, (int *)arg);
117 case WDIOC_SETOPTIONS:
118 {
119 if (get_user(options, (int *)arg))
120 return -EFAULT;
121 if (options & WDIOS_DISABLECARD) {
122 indydog_stop();
123 retval = 0;
124 }
125 if (options & WDIOS_ENABLECARD) {
126 indydog_start();
127 retval = 0;
128 }
129 return retval;
130 }
131 case WDIOC_KEEPALIVE:
132 indydog_ping();
133 return 0;
134 case WDIOC_GETTIMEOUT:
135 return put_user(WATCHDOG_TIMEOUT, (int *)arg);
136 default:
137 return -ENOTTY;
138 }
139}
140
141static int indydog_notify_sys(struct notifier_block *this,
142 unsigned long code, void *unused)
143{
144 if (code == SYS_DOWN || code == SYS_HALT)
145 indydog_stop();
146
147 return NOTIFY_DONE;
148}
149
150static const struct file_operations indydog_fops = {
151 .owner = THIS_MODULE,
152 .llseek = no_llseek,
153 .write = indydog_write,
154 .unlocked_ioctl = indydog_ioctl,
155 .compat_ioctl = compat_ptr_ioctl,
156 .open = indydog_open,
157 .release = indydog_release,
158};
159
160static struct miscdevice indydog_miscdev = {
161 .minor = WATCHDOG_MINOR,
162 .name = "watchdog",
163 .fops = &indydog_fops,
164};
165
166static struct notifier_block indydog_notifier = {
167 .notifier_call = indydog_notify_sys,
168};
169
170static int __init watchdog_init(void)
171{
172 int ret;
173
174 ret = register_reboot_notifier(&indydog_notifier);
175 if (ret) {
176 pr_err("cannot register reboot notifier (err=%d)\n", ret);
177 return ret;
178 }
179
180 ret = misc_register(&indydog_miscdev);
181 if (ret) {
182 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
183 WATCHDOG_MINOR, ret);
184 unregister_reboot_notifier(&indydog_notifier);
185 return ret;
186 }
187
188 pr_info("Hardware Watchdog Timer for SGI IP22: 0.3\n");
189
190 return 0;
191}
192
193static void __exit watchdog_exit(void)
194{
195 misc_deregister(&indydog_miscdev);
196 unregister_reboot_notifier(&indydog_notifier);
197}
198
199module_init(watchdog_init);
200module_exit(watchdog_exit);
201
202MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>");
203MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22");
204MODULE_LICENSE("GPL");
205
