44e81f7d4322909b168b691edb0c6d320419f2c0
[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
91 wafwdt_stop(void)
92 {
93         /* stop watchdog */
94         inb_p(wdt_stop);
95 }
96
97 static ssize_t wafwdt_write(struct file *file, const char __user *buf,
98                                                 size_t count, loff_t *ppos)
99 {
100         /* See if we got the magic character 'V' and reload the timer */
101         if (count) {
102                 if (!nowayout) {
103                         size_t i;
104
105                         /* In case it was set long ago */
106                         expect_close = 0;
107
108                         /* scan to see whether or not we got the magic
109                            character */
110                         for (i = 0; i != count; i++) {
111                                 char c;
112                                 if (get_user(c, buf + i))
113                                         return -EFAULT;
114                                 if (c == 'V')
115                                         expect_close = 42;
116                         }
117                 }
118                 /* Well, anyhow someone wrote to us, we should
119                    return that favour */
120                 wafwdt_ping();
121         }
122         return count;
123 }
124
125 static long wafwdt_ioctl(struct file *file, unsigned int cmd,
126                                                         unsigned long arg)
127 {
128         int new_timeout;
129         void __user *argp = (void __user *)arg;
130         int __user *p = argp;
131         static const struct watchdog_info ident = {
132                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
133                                                         WDIOF_MAGICCLOSE,
134                 .firmware_version = 1,
135                 .identity = "Wafer 5823 WDT",
136         };
137
138         switch (cmd) {
139         case WDIOC_GETSUPPORT:
140                 if (copy_to_user(argp, &ident, sizeof(ident)))
141                         return -EFAULT;
142                 break;
143
144         case WDIOC_GETSTATUS:
145         case WDIOC_GETBOOTSTATUS:
146                 return put_user(0, p);
147
148         case WDIOC_SETOPTIONS:
149         {
150                 int options, retval = -EINVAL;
151
152                 if (get_user(options, p))
153                         return -EFAULT;
154
155                 if (options & WDIOS_DISABLECARD) {
156                         wafwdt_start();
157                         retval = 0;
158                 }
159
160                 if (options & WDIOS_ENABLECARD) {
161                         wafwdt_stop();
162                         retval = 0;
163                 }
164
165                 return retval;
166         }
167
168         case WDIOC_KEEPALIVE:
169                 wafwdt_ping();
170                 break;
171
172         case WDIOC_SETTIMEOUT:
173                 if (get_user(new_timeout, p))
174                         return -EFAULT;
175                 if ((new_timeout < 1) || (new_timeout > 255))
176                         return -EINVAL;
177                 timeout = new_timeout;
178                 wafwdt_stop();
179                 wafwdt_start();
180                 /* Fall */
181         case WDIOC_GETTIMEOUT:
182                 return put_user(timeout, p);
183
184         default:
185                 return -ENOTTY;
186         }
187         return 0;
188 }
189
190 static int wafwdt_open(struct inode *inode, struct file *file)
191 {
192         if (test_and_set_bit(0, &wafwdt_is_open))
193                 return -EBUSY;
194
195         /*
196          *      Activate
197          */
198         wafwdt_start();
199         return nonseekable_open(inode, file);
200 }
201
202 static int
203 wafwdt_close(struct inode *inode, struct file *file)
204 {
205         if (expect_close == 42)
206                 wafwdt_stop();
207         else {
208                 printk(KERN_CRIT PFX
209                     "WDT device closed unexpectedly.  WDT will not stop!\n");
210                 wafwdt_ping();
211         }
212         clear_bit(0, &wafwdt_is_open);
213         expect_close = 0;
214         return 0;
215 }
216
217 /*
218  *      Notifier for system down
219  */
220
221 static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
222                                                                 void *unused)
223 {
224         if (code == SYS_DOWN || code == SYS_HALT)
225                 wafwdt_stop();
226         return NOTIFY_DONE;
227 }
228
229 /*
230  *      Kernel Interfaces
231  */
232
233 static const struct file_operations wafwdt_fops = {
234         .owner          = THIS_MODULE,
235         .llseek         = no_llseek,
236         .write          = wafwdt_write,
237         .unlocked_ioctl = wafwdt_ioctl,
238         .open           = wafwdt_open,
239         .release        = wafwdt_close,
240 };
241
242 static struct miscdevice wafwdt_miscdev = {
243         .minor  = WATCHDOG_MINOR,
244         .name   = "watchdog",
245         .fops   = &wafwdt_fops,
246 };
247
248 /*
249  *      The WDT needs to learn about soft shutdowns in order to
250  *      turn the timebomb registers off.
251  */
252
253 static struct notifier_block wafwdt_notifier = {
254         .notifier_call = wafwdt_notify_sys,
255 };
256
257 static int __init wafwdt_init(void)
258 {
259         int ret;
260
261         printk(KERN_INFO
262           "WDT driver for Wafer 5823 single board computer initialising.\n");
263
264         if (timeout < 1 || timeout > 255) {
265                 timeout = WD_TIMO;
266                 printk(KERN_INFO PFX
267                         "timeout value must be 1 <= x <= 255, using %d\n",
268                                                                 timeout);
269         }
270
271         if (wdt_stop != wdt_start) {
272                 if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
273                         printk(KERN_ERR PFX
274                                 "I/O address 0x%04x already in use\n",
275                                                                 wdt_stop);
276                         ret = -EIO;
277                         goto error;
278                 }
279         }
280
281         if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
282                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
283                         wdt_start);
284                 ret = -EIO;
285                 goto error2;
286         }
287
288         ret = register_reboot_notifier(&wafwdt_notifier);
289         if (ret != 0) {
290                 printk(KERN_ERR PFX
291                         "cannot register reboot notifier (err=%d)\n", ret);
292                 goto error3;
293         }
294
295         ret = misc_register(&wafwdt_miscdev);
296         if (ret != 0) {
297                 printk(KERN_ERR PFX
298                         "cannot register miscdev on minor=%d (err=%d)\n",
299                                                 WATCHDOG_MINOR, ret);
300                 goto error4;
301         }
302
303         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
304                 timeout, nowayout);
305
306         return ret;
307 error4:
308         unregister_reboot_notifier(&wafwdt_notifier);
309 error3:
310         release_region(wdt_start, 1);
311 error2:
312         if (wdt_stop != wdt_start)
313                 release_region(wdt_stop, 1);
314 error:
315         return ret;
316 }
317
318 static void __exit wafwdt_exit(void)
319 {
320         misc_deregister(&wafwdt_miscdev);
321         unregister_reboot_notifier(&wafwdt_notifier);
322         if (wdt_stop != wdt_start)
323                 release_region(wdt_stop, 1);
324         release_region(wdt_start, 1);
325 }
326
327 module_init(wafwdt_init);
328 module_exit(wafwdt_exit);
329
330 MODULE_AUTHOR("Justin Cormack");
331 MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
332 MODULE_LICENSE("GPL");
333 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
334
335 /* end of wafer5823wdt.c */