Fix common misspellings
[linux-2.6.git] / drivers / watchdog / sbc7240_wdt.c
1 /*
2  *      NANO7240 SBC Watchdog device driver
3  *
4  *      Based on w83877f.c by Scott Jennings,
5  *
6  *      This program is free software; you can redistribute it and/or modify
7  *      it under the terms of the GNU General Public License version 2 as
8  *      published by the Free Software Foundation;
9  *
10  *      Software distributed under the License is distributed on an "AS IS"
11  *      basis, WITHOUT WARRANTY OF ANY KIND, either express or
12  *      implied. See the License for the specific language governing
13  *      rights and limitations under the License.
14  *
15  *      (c) Copyright 2007  Gilles GIGAN <gilles.gigan@jcu.edu.au>
16  *
17  */
18
19 #include <linux/fs.h>
20 #include <linux/init.h>
21 #include <linux/ioport.h>
22 #include <linux/jiffies.h>
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/miscdevice.h>
26 #include <linux/notifier.h>
27 #include <linux/reboot.h>
28 #include <linux/types.h>
29 #include <linux/watchdog.h>
30 #include <linux/io.h>
31 #include <linux/uaccess.h>
32 #include <asm/atomic.h>
33 #include <asm/system.h>
34
35 #define SBC7240_PREFIX "sbc7240_wdt: "
36
37 #define SBC7240_ENABLE_PORT             0x443
38 #define SBC7240_DISABLE_PORT            0x043
39 #define SBC7240_SET_TIMEOUT_PORT        SBC7240_ENABLE_PORT
40 #define SBC7240_MAGIC_CHAR              'V'
41
42 #define SBC7240_TIMEOUT         30
43 #define SBC7240_MAX_TIMEOUT             255
44 static int timeout = SBC7240_TIMEOUT;   /* in seconds */
45 module_param(timeout, int, 0);
46 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
47                  __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
48                  __MODULE_STRING(SBC7240_TIMEOUT) ")");
49
50 static int nowayout = WATCHDOG_NOWAYOUT;
51 module_param(nowayout, int, 0);
52 MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
53
54 #define SBC7240_OPEN_STATUS_BIT         0
55 #define SBC7240_ENABLED_STATUS_BIT      1
56 #define SBC7240_EXPECT_CLOSE_STATUS_BIT 2
57 static unsigned long wdt_status;
58
59 /*
60  * Utility routines
61  */
62
63 static void wdt_disable(void)
64 {
65         /* disable the watchdog */
66         if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
67                 inb_p(SBC7240_DISABLE_PORT);
68                 printk(KERN_INFO SBC7240_PREFIX
69                        "Watchdog timer is now disabled.\n");
70         }
71 }
72
73 static void wdt_enable(void)
74 {
75         /* enable the watchdog */
76         if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
77                 inb_p(SBC7240_ENABLE_PORT);
78                 printk(KERN_INFO SBC7240_PREFIX
79                        "Watchdog timer is now enabled.\n");
80         }
81 }
82
83 static int wdt_set_timeout(int t)
84 {
85         if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
86                 printk(KERN_ERR SBC7240_PREFIX
87                        "timeout value must be 1<=x<=%d\n",
88                        SBC7240_MAX_TIMEOUT);
89                 return -1;
90         }
91         /* set the timeout */
92         outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
93         timeout = t;
94         printk(KERN_INFO SBC7240_PREFIX "timeout set to %d seconds\n", t);
95         return 0;
96 }
97
98 /* Whack the dog */
99 static inline void wdt_keepalive(void)
100 {
101         if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
102                 inb_p(SBC7240_ENABLE_PORT);
103 }
104
105 /*
106  * /dev/watchdog handling
107  */
108 static ssize_t fop_write(struct file *file, const char __user *buf,
109                          size_t count, loff_t *ppos)
110 {
111         size_t i;
112         char c;
113
114         if (count) {
115                 if (!nowayout) {
116                         clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
117                                 &wdt_status);
118
119                         /* is there a magic char ? */
120                         for (i = 0; i != count; i++) {
121                                 if (get_user(c, buf + i))
122                                         return -EFAULT;
123                                 if (c == SBC7240_MAGIC_CHAR) {
124                                         set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
125                                                 &wdt_status);
126                                         break;
127                                 }
128                         }
129                 }
130
131                 wdt_keepalive();
132         }
133
134         return count;
135 }
136
137 static int fop_open(struct inode *inode, struct file *file)
138 {
139         if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
140                 return -EBUSY;
141
142         wdt_enable();
143
144         return nonseekable_open(inode, file);
145 }
146
147 static int fop_close(struct inode *inode, struct file *file)
148 {
149         if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
150             || !nowayout) {
151                 wdt_disable();
152         } else {
153                 printk(KERN_CRIT SBC7240_PREFIX
154                        "Unexpected close, not stopping watchdog!\n");
155                 wdt_keepalive();
156         }
157
158         clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
159         return 0;
160 }
161
162 static const struct watchdog_info ident = {
163         .options = WDIOF_KEEPALIVEPING|
164                    WDIOF_SETTIMEOUT|
165                    WDIOF_MAGICCLOSE,
166         .firmware_version = 1,
167         .identity = "SBC7240",
168 };
169
170
171 static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
172 {
173         switch (cmd) {
174         case WDIOC_GETSUPPORT:
175                 return copy_to_user((void __user *)arg, &ident, sizeof(ident))
176                                                  ? -EFAULT : 0;
177         case WDIOC_GETSTATUS:
178         case WDIOC_GETBOOTSTATUS:
179                 return put_user(0, (int __user *)arg);
180         case WDIOC_SETOPTIONS:
181         {
182                 int options;
183                 int retval = -EINVAL;
184
185                 if (get_user(options, (int __user *)arg))
186                         return -EFAULT;
187
188                 if (options & WDIOS_DISABLECARD) {
189                         wdt_disable();
190                         retval = 0;
191                 }
192
193                 if (options & WDIOS_ENABLECARD) {
194                         wdt_enable();
195                         retval = 0;
196                 }
197
198                 return retval;
199         }
200         case WDIOC_KEEPALIVE:
201                 wdt_keepalive();
202                 return 0;
203         case WDIOC_SETTIMEOUT:
204         {
205                 int new_timeout;
206
207                 if (get_user(new_timeout, (int __user *)arg))
208                         return -EFAULT;
209
210                 if (wdt_set_timeout(new_timeout))
211                         return -EINVAL;
212
213                 /* Fall through */
214         }
215         case WDIOC_GETTIMEOUT:
216                 return put_user(timeout, (int __user *)arg);
217         default:
218                 return -ENOTTY;
219         }
220 }
221
222 static const struct file_operations wdt_fops = {
223         .owner = THIS_MODULE,
224         .llseek = no_llseek,
225         .write = fop_write,
226         .open = fop_open,
227         .release = fop_close,
228         .unlocked_ioctl = fop_ioctl,
229 };
230
231 static struct miscdevice wdt_miscdev = {
232         .minor = WATCHDOG_MINOR,
233         .name = "watchdog",
234         .fops = &wdt_fops,
235 };
236
237 /*
238  *      Notifier for system down
239  */
240
241 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
242                           void *unused)
243 {
244         if (code == SYS_DOWN || code == SYS_HALT)
245                 wdt_disable();
246         return NOTIFY_DONE;
247 }
248
249 static struct notifier_block wdt_notifier = {
250         .notifier_call = wdt_notify_sys,
251 };
252
253 static void __exit sbc7240_wdt_unload(void)
254 {
255         printk(KERN_INFO SBC7240_PREFIX "Removing watchdog\n");
256         misc_deregister(&wdt_miscdev);
257
258         unregister_reboot_notifier(&wdt_notifier);
259         release_region(SBC7240_ENABLE_PORT, 1);
260 }
261
262 static int __init sbc7240_wdt_init(void)
263 {
264         int rc = -EBUSY;
265
266         if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
267                 printk(KERN_ERR SBC7240_PREFIX
268                        "I/O address 0x%04x already in use\n",
269                        SBC7240_ENABLE_PORT);
270                 rc = -EIO;
271                 goto err_out;
272         }
273
274         /* The IO port 0x043 used to disable the watchdog
275          * is already claimed by the system timer, so we
276          * can't request_region() it ...*/
277
278         if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
279                 timeout = SBC7240_TIMEOUT;
280                 printk(KERN_INFO SBC7240_PREFIX
281                        "timeout value must be 1<=x<=%d, using %d\n",
282                        SBC7240_MAX_TIMEOUT, timeout);
283         }
284         wdt_set_timeout(timeout);
285         wdt_disable();
286
287         rc = register_reboot_notifier(&wdt_notifier);
288         if (rc) {
289                 printk(KERN_ERR SBC7240_PREFIX
290                        "cannot register reboot notifier (err=%d)\n", rc);
291                 goto err_out_region;
292         }
293
294         rc = misc_register(&wdt_miscdev);
295         if (rc) {
296                 printk(KERN_ERR SBC7240_PREFIX
297                        "cannot register miscdev on minor=%d (err=%d)\n",
298                        wdt_miscdev.minor, rc);
299                 goto err_out_reboot_notifier;
300         }
301
302         printk(KERN_INFO SBC7240_PREFIX
303                "Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
304                nowayout);
305
306         return 0;
307
308 err_out_reboot_notifier:
309         unregister_reboot_notifier(&wdt_notifier);
310 err_out_region:
311         release_region(SBC7240_ENABLE_PORT, 1);
312 err_out:
313         return rc;
314 }
315
316 module_init(sbc7240_wdt_init);
317 module_exit(sbc7240_wdt_unload);
318
319 MODULE_AUTHOR("Gilles Gigan");
320 MODULE_DESCRIPTION("Watchdog device driver for single board"
321                    " computers EPIC Nano 7240 from iEi");
322 MODULE_LICENSE("GPL");
323 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
324