This source file includes following definitions.
- wdt_disable
- wdt_enable
- wdt_set_timeout
- wdt_keepalive
- fop_write
- fop_open
- fop_close
- fop_ioctl
- wdt_notify_sys
- sbc7240_wdt_unload
- sbc7240_wdt_init
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10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <linux/fs.h>
13 #include <linux/init.h>
14 #include <linux/ioport.h>
15 #include <linux/jiffies.h>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/miscdevice.h>
19 #include <linux/notifier.h>
20 #include <linux/reboot.h>
21 #include <linux/types.h>
22 #include <linux/watchdog.h>
23 #include <linux/io.h>
24 #include <linux/uaccess.h>
25 #include <linux/atomic.h>
26
27 #define SBC7240_ENABLE_PORT 0x443
28 #define SBC7240_DISABLE_PORT 0x043
29 #define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT
30 #define SBC7240_MAGIC_CHAR 'V'
31
32 #define SBC7240_TIMEOUT 30
33 #define SBC7240_MAX_TIMEOUT 255
34 static int timeout = SBC7240_TIMEOUT;
35 module_param(timeout, int, 0);
36 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
37 __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
38 __MODULE_STRING(SBC7240_TIMEOUT) ")");
39
40 static bool nowayout = WATCHDOG_NOWAYOUT;
41 module_param(nowayout, bool, 0);
42 MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
43
44 #define SBC7240_OPEN_STATUS_BIT 0
45 #define SBC7240_ENABLED_STATUS_BIT 1
46 #define SBC7240_EXPECT_CLOSE_STATUS_BIT 2
47 static unsigned long wdt_status;
48
49
50
51
52
53 static void wdt_disable(void)
54 {
55
56 if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
57 inb_p(SBC7240_DISABLE_PORT);
58 pr_info("Watchdog timer is now disabled\n");
59 }
60 }
61
62 static void wdt_enable(void)
63 {
64
65 if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
66 inb_p(SBC7240_ENABLE_PORT);
67 pr_info("Watchdog timer is now enabled\n");
68 }
69 }
70
71 static int wdt_set_timeout(int t)
72 {
73 if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
74 pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT);
75 return -1;
76 }
77
78 outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
79 timeout = t;
80 pr_info("timeout set to %d seconds\n", t);
81 return 0;
82 }
83
84
85 static inline void wdt_keepalive(void)
86 {
87 if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
88 inb_p(SBC7240_ENABLE_PORT);
89 }
90
91
92
93
94 static ssize_t fop_write(struct file *file, const char __user *buf,
95 size_t count, loff_t *ppos)
96 {
97 size_t i;
98 char c;
99
100 if (count) {
101 if (!nowayout) {
102 clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
103 &wdt_status);
104
105
106 for (i = 0; i != count; i++) {
107 if (get_user(c, buf + i))
108 return -EFAULT;
109 if (c == SBC7240_MAGIC_CHAR) {
110 set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
111 &wdt_status);
112 break;
113 }
114 }
115 }
116
117 wdt_keepalive();
118 }
119
120 return count;
121 }
122
123 static int fop_open(struct inode *inode, struct file *file)
124 {
125 if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
126 return -EBUSY;
127
128 wdt_enable();
129
130 return stream_open(inode, file);
131 }
132
133 static int fop_close(struct inode *inode, struct file *file)
134 {
135 if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
136 || !nowayout) {
137 wdt_disable();
138 } else {
139 pr_crit("Unexpected close, not stopping watchdog!\n");
140 wdt_keepalive();
141 }
142
143 clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
144 return 0;
145 }
146
147 static const struct watchdog_info ident = {
148 .options = WDIOF_KEEPALIVEPING|
149 WDIOF_SETTIMEOUT|
150 WDIOF_MAGICCLOSE,
151 .firmware_version = 1,
152 .identity = "SBC7240",
153 };
154
155
156 static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
157 {
158 switch (cmd) {
159 case WDIOC_GETSUPPORT:
160 return copy_to_user((void __user *)arg, &ident, sizeof(ident))
161 ? -EFAULT : 0;
162 case WDIOC_GETSTATUS:
163 case WDIOC_GETBOOTSTATUS:
164 return put_user(0, (int __user *)arg);
165 case WDIOC_SETOPTIONS:
166 {
167 int options;
168 int retval = -EINVAL;
169
170 if (get_user(options, (int __user *)arg))
171 return -EFAULT;
172
173 if (options & WDIOS_DISABLECARD) {
174 wdt_disable();
175 retval = 0;
176 }
177
178 if (options & WDIOS_ENABLECARD) {
179 wdt_enable();
180 retval = 0;
181 }
182
183 return retval;
184 }
185 case WDIOC_KEEPALIVE:
186 wdt_keepalive();
187 return 0;
188 case WDIOC_SETTIMEOUT:
189 {
190 int new_timeout;
191
192 if (get_user(new_timeout, (int __user *)arg))
193 return -EFAULT;
194
195 if (wdt_set_timeout(new_timeout))
196 return -EINVAL;
197
198
199 }
200 case WDIOC_GETTIMEOUT:
201 return put_user(timeout, (int __user *)arg);
202 default:
203 return -ENOTTY;
204 }
205 }
206
207 static const struct file_operations wdt_fops = {
208 .owner = THIS_MODULE,
209 .llseek = no_llseek,
210 .write = fop_write,
211 .open = fop_open,
212 .release = fop_close,
213 .unlocked_ioctl = fop_ioctl,
214 };
215
216 static struct miscdevice wdt_miscdev = {
217 .minor = WATCHDOG_MINOR,
218 .name = "watchdog",
219 .fops = &wdt_fops,
220 };
221
222
223
224
225
226 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
227 void *unused)
228 {
229 if (code == SYS_DOWN || code == SYS_HALT)
230 wdt_disable();
231 return NOTIFY_DONE;
232 }
233
234 static struct notifier_block wdt_notifier = {
235 .notifier_call = wdt_notify_sys,
236 };
237
238 static void __exit sbc7240_wdt_unload(void)
239 {
240 pr_info("Removing watchdog\n");
241 misc_deregister(&wdt_miscdev);
242
243 unregister_reboot_notifier(&wdt_notifier);
244 release_region(SBC7240_ENABLE_PORT, 1);
245 }
246
247 static int __init sbc7240_wdt_init(void)
248 {
249 int rc = -EBUSY;
250
251 if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
252 pr_err("I/O address 0x%04x already in use\n",
253 SBC7240_ENABLE_PORT);
254 rc = -EIO;
255 goto err_out;
256 }
257
258
259
260
261
262 if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
263 timeout = SBC7240_TIMEOUT;
264 pr_info("timeout value must be 1<=x<=%d, using %d\n",
265 SBC7240_MAX_TIMEOUT, timeout);
266 }
267 wdt_set_timeout(timeout);
268 wdt_disable();
269
270 rc = register_reboot_notifier(&wdt_notifier);
271 if (rc) {
272 pr_err("cannot register reboot notifier (err=%d)\n", rc);
273 goto err_out_region;
274 }
275
276 rc = misc_register(&wdt_miscdev);
277 if (rc) {
278 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
279 wdt_miscdev.minor, rc);
280 goto err_out_reboot_notifier;
281 }
282
283 pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
284 nowayout);
285
286 return 0;
287
288 err_out_reboot_notifier:
289 unregister_reboot_notifier(&wdt_notifier);
290 err_out_region:
291 release_region(SBC7240_ENABLE_PORT, 1);
292 err_out:
293 return rc;
294 }
295
296 module_init(sbc7240_wdt_init);
297 module_exit(sbc7240_wdt_unload);
298
299 MODULE_AUTHOR("Gilles Gigan");
300 MODULE_DESCRIPTION("Watchdog device driver for single board"
301 " computers EPIC Nano 7240 from iEi");
302 MODULE_LICENSE("GPL");