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16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/types.h>
19#include <linux/kernel.h>
20#include <linux/fs.h>
21#include <linux/mm.h>
22#include <linux/miscdevice.h>
23#include <linux/watchdog.h>
24#include <linux/notifier.h>
25#include <linux/reboot.h>
26#include <linux/init.h>
27#include <linux/ioport.h>
28#include <linux/uaccess.h>
29#include <linux/io.h>
30
31#define PFX "epx_c3: "
32static int epx_c3_alive;
33
34#define WATCHDOG_TIMEOUT 1
35
36static int nowayout = WATCHDOG_NOWAYOUT;
37module_param(nowayout, int, 0);
38MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
39 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
40
41#define EPXC3_WATCHDOG_CTL_REG 0x1ee
42#define EPXC3_WATCHDOG_PET_REG 0x1ef
43
44static void epx_c3_start(void)
45{
46 outb(1, EPXC3_WATCHDOG_CTL_REG);
47}
48
49static void epx_c3_stop(void)
50{
51
52 outb(0, EPXC3_WATCHDOG_CTL_REG);
53
54 printk(KERN_INFO PFX "Stopped watchdog timer.\n");
55}
56
57static void epx_c3_pet(void)
58{
59 outb(1, EPXC3_WATCHDOG_PET_REG);
60}
61
62
63
64
65static int epx_c3_open(struct inode *inode, struct file *file)
66{
67 if (epx_c3_alive)
68 return -EBUSY;
69
70 if (nowayout)
71 __module_get(THIS_MODULE);
72
73
74 epx_c3_start();
75 epx_c3_pet();
76
77 epx_c3_alive = 1;
78 printk(KERN_INFO "Started watchdog timer.\n");
79
80 return nonseekable_open(inode, file);
81}
82
83static int epx_c3_release(struct inode *inode, struct file *file)
84{
85
86
87 if (!nowayout)
88 epx_c3_stop();
89
90 epx_c3_alive = 0;
91
92 return 0;
93}
94
95static ssize_t epx_c3_write(struct file *file, const char __user *data,
96 size_t len, loff_t *ppos)
97{
98
99 if (len)
100 epx_c3_pet();
101 return len;
102}
103
104static long epx_c3_ioctl(struct file *file, unsigned int cmd,
105 unsigned long arg)
106{
107 int options, retval = -EINVAL;
108 int __user *argp = (void __user *)arg;
109 static const struct watchdog_info ident = {
110 .options = WDIOF_KEEPALIVEPING |
111 WDIOF_MAGICCLOSE,
112 .firmware_version = 0,
113 .identity = "Winsystems EPX-C3 H/W Watchdog",
114 };
115
116 switch (cmd) {
117 case WDIOC_GETSUPPORT:
118 if (copy_to_user(argp, &ident, sizeof(ident)))
119 return -EFAULT;
120 return 0;
121 case WDIOC_GETSTATUS:
122 case WDIOC_GETBOOTSTATUS:
123 return put_user(0, argp);
124 case WDIOC_SETOPTIONS:
125 if (get_user(options, argp))
126 return -EFAULT;
127
128 if (options & WDIOS_DISABLECARD) {
129 epx_c3_stop();
130 retval = 0;
131 }
132
133 if (options & WDIOS_ENABLECARD) {
134 epx_c3_start();
135 retval = 0;
136 }
137
138 return retval;
139 case WDIOC_KEEPALIVE:
140 epx_c3_pet();
141 return 0;
142 case WDIOC_GETTIMEOUT:
143 return put_user(WATCHDOG_TIMEOUT, argp);
144 default:
145 return -ENOTTY;
146 }
147}
148
149static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code,
150 void *unused)
151{
152 if (code == SYS_DOWN || code == SYS_HALT)
153 epx_c3_stop();
154
155 return NOTIFY_DONE;
156}
157
158static const struct file_operations epx_c3_fops = {
159 .owner = THIS_MODULE,
160 .llseek = no_llseek,
161 .write = epx_c3_write,
162 .unlocked_ioctl = epx_c3_ioctl,
163 .open = epx_c3_open,
164 .release = epx_c3_release,
165};
166
167static struct miscdevice epx_c3_miscdev = {
168 .minor = WATCHDOG_MINOR,
169 .name = "watchdog",
170 .fops = &epx_c3_fops,
171};
172
173static struct notifier_block epx_c3_notifier = {
174 .notifier_call = epx_c3_notify_sys,
175};
176
177static const char banner[] __initdata =
178 KERN_INFO PFX "Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n";
179
180static int __init watchdog_init(void)
181{
182 int ret;
183
184 if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
185 return -EBUSY;
186
187 ret = register_reboot_notifier(&epx_c3_notifier);
188 if (ret) {
189 printk(KERN_ERR PFX "cannot register reboot notifier "
190 "(err=%d)\n", ret);
191 goto out;
192 }
193
194 ret = misc_register(&epx_c3_miscdev);
195 if (ret) {
196 printk(KERN_ERR PFX "cannot register miscdev on minor=%d "
197 "(err=%d)\n", WATCHDOG_MINOR, ret);
198 unregister_reboot_notifier(&epx_c3_notifier);
199 goto out;
200 }
201
202 printk(banner);
203
204 return 0;
205
206out:
207 release_region(EPXC3_WATCHDOG_CTL_REG, 2);
208 return ret;
209}
210
211static void __exit watchdog_exit(void)
212{
213 misc_deregister(&epx_c3_miscdev);
214 unregister_reboot_notifier(&epx_c3_notifier);
215 release_region(EPXC3_WATCHDOG_CTL_REG, 2);
216}
217
218module_init(watchdog_init);
219module_exit(watchdog_exit);
220
221MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
222MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. Note that there is no way to probe for this device -- so only use it if you are *sure* you are runnning on this specific SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!");
223MODULE_LICENSE("GPL");
224MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
225
