[WATCHDOG] more coding style clean-up's
[linux-2.6.git] / drivers / watchdog / wafer5823wdt.c
1 /*
2  *      ICP Wafer 5823 Single Board Computer WDT driver
3  *      http://www.icpamerica.com/wafer_5823.php
4  *      May also work on other similar models
5  *
6  *      (c) Copyright 2002 Justin Cormack <justin@street-vision.com>
7  *
8  *      Release 0.02
9  *
10  *      Based on advantechwdt.c which is based on wdt.c.
11  *      Original copyright messages:
12  *
13  *      (c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved.
14  *                              http://www.redhat.com
15  *
16  *      This program is free software; you can redistribute it and/or
17  *      modify it under the terms of the GNU General Public License
18  *      as published by the Free Software Foundation; either version
19  *      2 of the License, or (at your option) any later version.
20  *
21  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
22  *      warranty for any of this software. This material is provided
23  *      "AS-IS" and at no charge.
24  *
25  *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
26  *
27  */
28
29 #include <linux/module.h>
30 #include <linux/moduleparam.h>
31 #include <linux/miscdevice.h>
32 #include <linux/watchdog.h>
33 #include <linux/fs.h>
34 #include <linux/ioport.h>
35 #include <linux/notifier.h>
36 #include <linux/reboot.h>
37 #include <linux/init.h>
38 #include <linux/spinlock.h>
39 #include <linux/io.h>
40 #include <linux/uaccess.h>
41
42 #define WATCHDOG_NAME "Wafer 5823 WDT"
43 #define PFX WATCHDOG_NAME ": "
44 #define WD_TIMO 60                      /* 60 sec default timeout */
45
46 static unsigned long wafwdt_is_open;
47 static char expect_close;
48 static DEFINE_SPINLOCK(wafwdt_lock);
49
50 /*
51  *      You must set these - there is no sane way to probe for this board.
52  *
53  *      To enable, write the timeout value in seconds (1 to 255) to I/O
54  *      port WDT_START, then read the port to start the watchdog. To pat
55  *      the dog, read port WDT_STOP to stop the timer, then read WDT_START
56  *      to restart it again.
57  */
58
59 static int wdt_stop = 0x843;
60 static int wdt_start = 0x443;
61
62 static int timeout = WD_TIMO;  /* in seconds */
63 module_param(timeout, int, 0);
64 MODULE_PARM_DESC(timeout,
65                 "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
66                                 __MODULE_STRING(WD_TIMO) ".");
67
68 static int nowayout = WATCHDOG_NOWAYOUT;
69 module_param(nowayout, int, 0);
70 MODULE_PARM_DESC(nowayout,
71                 "Watchdog cannot be stopped once started (default="
72                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
73
74 static void wafwdt_ping(void)
75 {
76         /* pat watchdog */
77         spin_lock(&wafwdt_lock);
78         inb_p(wdt_stop);
79         inb_p(wdt_start);
80         spin_unlock(&wafwdt_lock);
81 }
82
83 static void wafwdt_start(void)
84 {
85         /* start up watchdog */
86         outb_p(timeout, wdt_start);
87         inb_p(wdt_start);
88 }
89
90 static void wafwdt_stop(void)
91 {
92         /* stop watchdog */
93         inb_p(wdt_stop);
94 }
95
96 static ssize_t wafwdt_write(struct file *file, const char __user *buf,
97                                                 size_t count, loff_t *ppos)
98 {
99         /* See if we got the magic character 'V' and reload the timer */
100         if (count) {
101                 if (!nowayout) {
102                         size_t i;
103
104                         /* In case it was set long ago */
105                         expect_close = 0;
106
107                         /* scan to see whether or not we got the magic
108                            character */
109                         for (i = 0; i != count; i++) {
110                                 char c;
111                                 if (get_user(c, buf + i))
112                                         return -EFAULT;
113                                 if (c == 'V')
114                                         expect_close = 42;
115                         }
116                 }
117                 /* Well, anyhow someone wrote to us, we should
118                    return that favour */
119                 wafwdt_ping();
120         }
121         return count;
122 }
123
124 static long wafwdt_ioctl(struct file *file, unsigned int cmd,
125                                                         unsigned long arg)
126 {
127         int new_timeout;
128         void __user *argp = (void __user *)arg;
129         int __user *p = argp;
130         static const struct watchdog_info ident = {
131                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
132                                                         WDIOF_MAGICCLOSE,
133                 .firmware_version = 1,
134                 .identity = "Wafer 5823 WDT",
135         };
136
137         switch (cmd) {
138         case WDIOC_GETSUPPORT:
139                 if (copy_to_user(argp, &ident, sizeof(ident)))
140                         return -EFAULT;
141                 break;
142
143         case WDIOC_GETSTATUS:
144         case WDIOC_GETBOOTSTATUS:
145                 return put_user(0, p);
146
147         case WDIOC_SETOPTIONS:
148         {
149                 int options, retval = -EINVAL;
150
151                 if (get_user(options, p))
152                         return -EFAULT;
153
154                 if (options & WDIOS_DISABLECARD) {
155                         wafwdt_start();
156                         retval = 0;
157                 }
158
159                 if (options & WDIOS_ENABLECARD) {
160                         wafwdt_stop();
161                         retval = 0;
162                 }
163
164                 return retval;
165         }
166
167         case WDIOC_KEEPALIVE:
168                 wafwdt_ping();
169                 break;
170
171         case WDIOC_SETTIMEOUT:
172                 if (get_user(new_timeout, p))
173                         return -EFAULT;
174                 if ((new_timeout < 1) || (new_timeout > 255))
175                         return -EINVAL;
176                 timeout = new_timeout;
177                 wafwdt_stop();
178                 wafwdt_start();
179                 /* Fall */
180         case WDIOC_GETTIMEOUT:
181                 return put_user(timeout, p);
182
183         default:
184                 return -ENOTTY;
185         }
186         return 0;
187 }
188
189 static int wafwdt_open(struct inode *inode, struct file *file)
190 {
191         if (test_and_set_bit(0, &wafwdt_is_open))
192                 return -EBUSY;
193
194         /*
195          *      Activate
196          */
197         wafwdt_start();
198         return nonseekable_open(inode, file);
199 }
200
201 static int wafwdt_close(struct inode *inode, struct file *file)
202 {
203         if (expect_close == 42)
204                 wafwdt_stop();
205         else {
206                 printk(KERN_CRIT PFX
207                     "WDT device closed unexpectedly.  WDT will not stop!\n");
208                 wafwdt_ping();
209         }
210         clear_bit(0, &wafwdt_is_open);
211         expect_close = 0;
212         return 0;
213 }
214
215 /*
216  *      Notifier for system down
217  */
218
219 static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
220                                                                 void *unused)
221 {
222         if (code == SYS_DOWN || code == SYS_HALT)
223                 wafwdt_stop();
224         return NOTIFY_DONE;
225 }
226
227 /*
228  *      Kernel Interfaces
229  */
230
231 static const struct file_operations wafwdt_fops = {
232         .owner          = THIS_MODULE,
233         .llseek         = no_llseek,
234         .write          = wafwdt_write,
235         .unlocked_ioctl = wafwdt_ioctl,
236         .open           = wafwdt_open,
237         .release        = wafwdt_close,
238 };
239
240 static struct miscdevice wafwdt_miscdev = {
241         .minor  = WATCHDOG_MINOR,
242         .name   = "watchdog",
243         .fops   = &wafwdt_fops,
244 };
245
246 /*
247  *      The WDT needs to learn about soft shutdowns in order to
248  *      turn the timebomb registers off.
249  */
250
251 static struct notifier_block wafwdt_notifier = {
252         .notifier_call = wafwdt_notify_sys,
253 };
254
255 static int __init wafwdt_init(void)
256 {
257         int ret;
258
259         printk(KERN_INFO
260           "WDT driver for Wafer 5823 single board computer initialising.\n");
261
262         if (timeout < 1 || timeout > 255) {
263                 timeout = WD_TIMO;
264                 printk(KERN_INFO PFX
265                         "timeout value must be 1 <= x <= 255, using %d\n",
266                                                                 timeout);
267         }
268
269         if (wdt_stop != wdt_start) {
270                 if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
271                         printk(KERN_ERR PFX
272                                 "I/O address 0x%04x already in use\n",
273                                                                 wdt_stop);
274                         ret = -EIO;
275                         goto error;
276                 }
277         }
278
279         if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
280                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
281                         wdt_start);
282                 ret = -EIO;
283                 goto error2;
284         }
285
286         ret = register_reboot_notifier(&wafwdt_notifier);
287         if (ret != 0) {
288                 printk(KERN_ERR PFX
289                         "cannot register reboot notifier (err=%d)\n", ret);
290                 goto error3;
291         }
292
293         ret = misc_register(&wafwdt_miscdev);
294         if (ret != 0) {
295                 printk(KERN_ERR PFX
296                         "cannot register miscdev on minor=%d (err=%d)\n",
297                                                 WATCHDOG_MINOR, ret);
298                 goto error4;
299         }
300
301         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
302                 timeout, nowayout);
303
304         return ret;
305 error4:
306         unregister_reboot_notifier(&wafwdt_notifier);
307 error3:
308         release_region(wdt_start, 1);
309 error2:
310         if (wdt_stop != wdt_start)
311                 release_region(wdt_stop, 1);
312 error:
313         return ret;
314 }
315
316 static void __exit wafwdt_exit(void)
317 {
318         misc_deregister(&wafwdt_miscdev);
319         unregister_reboot_notifier(&wafwdt_notifier);
320         if (wdt_stop != wdt_start)
321                 release_region(wdt_stop, 1);
322         release_region(wdt_start, 1);
323 }
324
325 module_init(wafwdt_init);
326 module_exit(wafwdt_exit);
327
328 MODULE_AUTHOR("Justin Cormack");
329 MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
330 MODULE_LICENSE("GPL");
331 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
332
333 /* end of wafer5823wdt.c */