watchdog: nowayout is bool
[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@lxorguk.ukuu.org.uk>,
14  *                                              All Rights Reserved.
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30
31 #include <linux/module.h>
32 #include <linux/moduleparam.h>
33 #include <linux/miscdevice.h>
34 #include <linux/watchdog.h>
35 #include <linux/fs.h>
36 #include <linux/ioport.h>
37 #include <linux/notifier.h>
38 #include <linux/reboot.h>
39 #include <linux/init.h>
40 #include <linux/spinlock.h>
41 #include <linux/io.h>
42 #include <linux/uaccess.h>
43
44 #define WATCHDOG_NAME "Wafer 5823 WDT"
45 #define PFX WATCHDOG_NAME ": "
46 #define WD_TIMO 60                      /* 60 sec default timeout */
47
48 static unsigned long wafwdt_is_open;
49 static char expect_close;
50 static DEFINE_SPINLOCK(wafwdt_lock);
51
52 /*
53  *      You must set these - there is no sane way to probe for this board.
54  *
55  *      To enable, write the timeout value in seconds (1 to 255) to I/O
56  *      port WDT_START, then read the port to start the watchdog. To pat
57  *      the dog, read port WDT_STOP to stop the timer, then read WDT_START
58  *      to restart it again.
59  */
60
61 static int wdt_stop = 0x843;
62 static int wdt_start = 0x443;
63
64 static int timeout = WD_TIMO;  /* in seconds */
65 module_param(timeout, int, 0);
66 MODULE_PARM_DESC(timeout,
67                 "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
68                                 __MODULE_STRING(WD_TIMO) ".");
69
70 static bool nowayout = WATCHDOG_NOWAYOUT;
71 module_param(nowayout, bool, 0);
72 MODULE_PARM_DESC(nowayout,
73                 "Watchdog cannot be stopped once started (default="
74                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
75
76 static void wafwdt_ping(void)
77 {
78         /* pat watchdog */
79         spin_lock(&wafwdt_lock);
80         inb_p(wdt_stop);
81         inb_p(wdt_start);
82         spin_unlock(&wafwdt_lock);
83 }
84
85 static void wafwdt_start(void)
86 {
87         /* start up watchdog */
88         outb_p(timeout, wdt_start);
89         inb_p(wdt_start);
90 }
91
92 static void wafwdt_stop(void)
93 {
94         /* stop watchdog */
95         inb_p(wdt_stop);
96 }
97
98 static ssize_t wafwdt_write(struct file *file, const char __user *buf,
99                                                 size_t count, loff_t *ppos)
100 {
101         /* See if we got the magic character 'V' and reload the timer */
102         if (count) {
103                 if (!nowayout) {
104                         size_t i;
105
106                         /* In case it was set long ago */
107                         expect_close = 0;
108
109                         /* scan to see whether or not we got the magic
110                            character */
111                         for (i = 0; i != count; i++) {
112                                 char c;
113                                 if (get_user(c, buf + i))
114                                         return -EFAULT;
115                                 if (c == 'V')
116                                         expect_close = 42;
117                         }
118                 }
119                 /* Well, anyhow someone wrote to us, we should
120                    return that favour */
121                 wafwdt_ping();
122         }
123         return count;
124 }
125
126 static long wafwdt_ioctl(struct file *file, unsigned int cmd,
127                                                         unsigned long arg)
128 {
129         int new_timeout;
130         void __user *argp = (void __user *)arg;
131         int __user *p = argp;
132         static const struct watchdog_info ident = {
133                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
134                                                         WDIOF_MAGICCLOSE,
135                 .firmware_version = 1,
136                 .identity = "Wafer 5823 WDT",
137         };
138
139         switch (cmd) {
140         case WDIOC_GETSUPPORT:
141                 if (copy_to_user(argp, &ident, sizeof(ident)))
142                         return -EFAULT;
143                 break;
144
145         case WDIOC_GETSTATUS:
146         case WDIOC_GETBOOTSTATUS:
147                 return put_user(0, p);
148
149         case WDIOC_SETOPTIONS:
150         {
151                 int options, retval = -EINVAL;
152
153                 if (get_user(options, p))
154                         return -EFAULT;
155
156                 if (options & WDIOS_DISABLECARD) {
157                         wafwdt_stop();
158                         retval = 0;
159                 }
160
161                 if (options & WDIOS_ENABLECARD) {
162                         wafwdt_start();
163                         retval = 0;
164                 }
165
166                 return retval;
167         }
168
169         case WDIOC_KEEPALIVE:
170                 wafwdt_ping();
171                 break;
172
173         case WDIOC_SETTIMEOUT:
174                 if (get_user(new_timeout, p))
175                         return -EFAULT;
176                 if ((new_timeout < 1) || (new_timeout > 255))
177                         return -EINVAL;
178                 timeout = new_timeout;
179                 wafwdt_stop();
180                 wafwdt_start();
181                 /* Fall */
182         case WDIOC_GETTIMEOUT:
183                 return put_user(timeout, p);
184
185         default:
186                 return -ENOTTY;
187         }
188         return 0;
189 }
190
191 static int wafwdt_open(struct inode *inode, struct file *file)
192 {
193         if (test_and_set_bit(0, &wafwdt_is_open))
194                 return -EBUSY;
195
196         /*
197          *      Activate
198          */
199         wafwdt_start();
200         return nonseekable_open(inode, file);
201 }
202
203 static int wafwdt_close(struct inode *inode, struct file *file)
204 {
205         if (expect_close == 42)
206                 wafwdt_stop();
207         else {
208                 pr_crit("WDT device closed unexpectedly.  WDT will not stop!\n");
209                 wafwdt_ping();
210         }
211         clear_bit(0, &wafwdt_is_open);
212         expect_close = 0;
213         return 0;
214 }
215
216 /*
217  *      Notifier for system down
218  */
219
220 static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
221                                                                 void *unused)
222 {
223         if (code == SYS_DOWN || code == SYS_HALT)
224                 wafwdt_stop();
225         return NOTIFY_DONE;
226 }
227
228 /*
229  *      Kernel Interfaces
230  */
231
232 static const struct file_operations wafwdt_fops = {
233         .owner          = THIS_MODULE,
234         .llseek         = no_llseek,
235         .write          = wafwdt_write,
236         .unlocked_ioctl = wafwdt_ioctl,
237         .open           = wafwdt_open,
238         .release        = wafwdt_close,
239 };
240
241 static struct miscdevice wafwdt_miscdev = {
242         .minor  = WATCHDOG_MINOR,
243         .name   = "watchdog",
244         .fops   = &wafwdt_fops,
245 };
246
247 /*
248  *      The WDT needs to learn about soft shutdowns in order to
249  *      turn the timebomb registers off.
250  */
251
252 static struct notifier_block wafwdt_notifier = {
253         .notifier_call = wafwdt_notify_sys,
254 };
255
256 static int __init wafwdt_init(void)
257 {
258         int ret;
259
260         pr_info("WDT driver for Wafer 5823 single board computer initialising\n");
261
262         if (timeout < 1 || timeout > 255) {
263                 timeout = WD_TIMO;
264                 pr_info("timeout value must be 1 <= x <= 255, using %d\n",
265                         timeout);
266         }
267
268         if (wdt_stop != wdt_start) {
269                 if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
270                         pr_err("I/O address 0x%04x already in use\n", wdt_stop);
271                         ret = -EIO;
272                         goto error;
273                 }
274         }
275
276         if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
277                 pr_err("I/O address 0x%04x already in use\n", wdt_start);
278                 ret = -EIO;
279                 goto error2;
280         }
281
282         ret = register_reboot_notifier(&wafwdt_notifier);
283         if (ret != 0) {
284                 pr_err("cannot register reboot notifier (err=%d)\n", ret);
285                 goto error3;
286         }
287
288         ret = misc_register(&wafwdt_miscdev);
289         if (ret != 0) {
290                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
291                        WATCHDOG_MINOR, ret);
292                 goto error4;
293         }
294
295         pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
296                 timeout, nowayout);
297
298         return ret;
299 error4:
300         unregister_reboot_notifier(&wafwdt_notifier);
301 error3:
302         release_region(wdt_start, 1);
303 error2:
304         if (wdt_stop != wdt_start)
305                 release_region(wdt_stop, 1);
306 error:
307         return ret;
308 }
309
310 static void __exit wafwdt_exit(void)
311 {
312         misc_deregister(&wafwdt_miscdev);
313         unregister_reboot_notifier(&wafwdt_notifier);
314         if (wdt_stop != wdt_start)
315                 release_region(wdt_stop, 1);
316         release_region(wdt_start, 1);
317 }
318
319 module_init(wafwdt_init);
320 module_exit(wafwdt_exit);
321
322 MODULE_AUTHOR("Justin Cormack");
323 MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
324 MODULE_LICENSE("GPL");
325 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
326
327 /* end of wafer5823wdt.c */