watchdog: nowayout is bool
[linux-2.6.git] / drivers / watchdog / w83697ug_wdt.c
1 /*
2  *      w83697ug/uf WDT driver
3  *
4  *      (c) Copyright 2008 Flemming Fransen <ff@nrvissing.net>
5  *              reused original code to support w83697ug/uf.
6  *
7  *      Based on w83627hf_wdt.c which is based on advantechwdt.c
8  *      which is based on wdt.c.
9  *      Original copyright messages:
10  *
11  *      (c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
12  *              added support for W83627THF.
13  *
14  *      (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
15  *
16  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
17  *
18  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
19  *                              http://www.redhat.com
20  *
21  *      This program is free software; you can redistribute it and/or
22  *      modify it under the terms of the GNU General Public License
23  *      as published by the Free Software Foundation; either version
24  *      2 of the License, or (at your option) any later version.
25  *
26  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
27  *      warranty for any of this software. This material is provided
28  *      "AS-IS" and at no charge.
29  *
30  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
31  */
32
33 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34
35 #include <linux/module.h>
36 #include <linux/moduleparam.h>
37 #include <linux/types.h>
38 #include <linux/miscdevice.h>
39 #include <linux/watchdog.h>
40 #include <linux/fs.h>
41 #include <linux/ioport.h>
42 #include <linux/notifier.h>
43 #include <linux/reboot.h>
44 #include <linux/init.h>
45 #include <linux/spinlock.h>
46 #include <linux/io.h>
47 #include <linux/uaccess.h>
48
49 #include <asm/system.h>
50
51 #define WATCHDOG_NAME "w83697ug/uf WDT"
52 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
53
54 static unsigned long wdt_is_open;
55 static char expect_close;
56 static DEFINE_SPINLOCK(io_lock);
57
58 static int wdt_io = 0x2e;
59 module_param(wdt_io, int, 0);
60 MODULE_PARM_DESC(wdt_io, "w83697ug/uf WDT io port (default 0x2e)");
61
62 static int timeout = WATCHDOG_TIMEOUT;  /* 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(WATCHDOG_TIMEOUT) ")");
67
68 static bool nowayout = WATCHDOG_NOWAYOUT;
69 module_param(nowayout, bool, 0);
70 MODULE_PARM_DESC(nowayout,
71         "Watchdog cannot be stopped once started (default="
72                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
73
74 /*
75  *      Kernel methods.
76  */
77
78 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
79 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
80                                                         (same as EFER) */
81 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
82
83 static int w83697ug_select_wd_register(void)
84 {
85         unsigned char c;
86         unsigned char version;
87
88         outb_p(0x87, WDT_EFER); /* Enter extended function mode */
89         outb_p(0x87, WDT_EFER); /* Again according to manual */
90
91         outb(0x20, WDT_EFER);   /* check chip version   */
92         version = inb(WDT_EFDR);
93
94         if (version == 0x68) {  /* W83697UG             */
95                 pr_info("Watchdog chip version 0x%02x = W83697UG/UF found at 0x%04x\n",
96                         version, wdt_io);
97
98                 outb_p(0x2b, WDT_EFER);
99                 c = inb_p(WDT_EFDR);    /* select WDT0 */
100                 c &= ~0x04;
101                 outb_p(0x2b, WDT_EFER);
102                 outb_p(c, WDT_EFDR);    /* set pin118 to WDT0 */
103
104         } else {
105                 pr_err("No W83697UG/UF could be found\n");
106                 return -ENODEV;
107         }
108
109         outb_p(0x07, WDT_EFER); /* point to logical device number reg */
110         outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
111         outb_p(0x30, WDT_EFER); /* select CR30 */
112         c = inb_p(WDT_EFDR);
113         outb_p(c | 0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
114
115         return 0;
116 }
117
118 static void w83697ug_unselect_wd_register(void)
119 {
120         outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
121 }
122
123 static int w83697ug_init(void)
124 {
125         int ret;
126         unsigned char t;
127
128         ret = w83697ug_select_wd_register();
129         if (ret != 0)
130                 return ret;
131
132         outb_p(0xF6, WDT_EFER); /* Select CRF6 */
133         t = inb_p(WDT_EFDR);    /* read CRF6 */
134         if (t != 0) {
135                 pr_info("Watchdog already running. Resetting timeout to %d sec\n",
136                         timeout);
137                 outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
138         }
139         outb_p(0xF5, WDT_EFER); /* Select CRF5 */
140         t = inb_p(WDT_EFDR);    /* read CRF5 */
141         t &= ~0x0C;             /* set second mode &
142                                         disable keyboard turning off watchdog */
143         outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
144
145         w83697ug_unselect_wd_register();
146         return 0;
147 }
148
149 static void wdt_ctrl(int timeout)
150 {
151         spin_lock(&io_lock);
152
153         if (w83697ug_select_wd_register() < 0) {
154                 spin_unlock(&io_lock);
155                 return;
156         }
157
158         outb_p(0xF4, WDT_EFER);    /* Select CRF4 */
159         outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
160
161         w83697ug_unselect_wd_register();
162
163         spin_unlock(&io_lock);
164 }
165
166 static int wdt_ping(void)
167 {
168         wdt_ctrl(timeout);
169         return 0;
170 }
171
172 static int wdt_disable(void)
173 {
174         wdt_ctrl(0);
175         return 0;
176 }
177
178 static int wdt_set_heartbeat(int t)
179 {
180         if (t < 1 || t > 255)
181                 return -EINVAL;
182
183         timeout = t;
184         return 0;
185 }
186
187 static ssize_t wdt_write(struct file *file, const char __user *buf,
188                                                 size_t count, loff_t *ppos)
189 {
190         if (count) {
191                 if (!nowayout) {
192                         size_t i;
193
194                         expect_close = 0;
195
196                         for (i = 0; i != count; i++) {
197                                 char c;
198                                 if (get_user(c, buf + i))
199                                         return -EFAULT;
200                                 if (c == 'V')
201                                         expect_close = 42;
202                         }
203                 }
204                 wdt_ping();
205         }
206         return count;
207 }
208
209 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
210 {
211         void __user *argp = (void __user *)arg;
212         int __user *p = argp;
213         int new_timeout;
214         static const struct watchdog_info ident = {
215                 .options =              WDIOF_KEEPALIVEPING |
216                                         WDIOF_SETTIMEOUT |
217                                         WDIOF_MAGICCLOSE,
218                 .firmware_version =     1,
219                 .identity =             "W83697UG WDT",
220         };
221
222         switch (cmd) {
223         case WDIOC_GETSUPPORT:
224                 if (copy_to_user(argp, &ident, sizeof(ident)))
225                         return -EFAULT;
226                 break;
227
228         case WDIOC_GETSTATUS:
229         case WDIOC_GETBOOTSTATUS:
230                 return put_user(0, p);
231
232         case WDIOC_SETOPTIONS:
233         {
234                 int options, retval = -EINVAL;
235
236                 if (get_user(options, p))
237                         return -EFAULT;
238
239                 if (options & WDIOS_DISABLECARD) {
240                         wdt_disable();
241                         retval = 0;
242                 }
243
244                 if (options & WDIOS_ENABLECARD) {
245                         wdt_ping();
246                         retval = 0;
247                 }
248
249                 return retval;
250         }
251
252         case WDIOC_KEEPALIVE:
253                 wdt_ping();
254                 break;
255
256         case WDIOC_SETTIMEOUT:
257                 if (get_user(new_timeout, p))
258                         return -EFAULT;
259                 if (wdt_set_heartbeat(new_timeout))
260                         return -EINVAL;
261                 wdt_ping();
262                 /* Fall */
263
264         case WDIOC_GETTIMEOUT:
265                 return put_user(timeout, p);
266
267         default:
268                 return -ENOTTY;
269         }
270         return 0;
271 }
272
273 static int wdt_open(struct inode *inode, struct file *file)
274 {
275         if (test_and_set_bit(0, &wdt_is_open))
276                 return -EBUSY;
277         /*
278          *      Activate
279          */
280
281         wdt_ping();
282         return nonseekable_open(inode, file);
283 }
284
285 static int wdt_close(struct inode *inode, struct file *file)
286 {
287         if (expect_close == 42)
288                 wdt_disable();
289         else {
290                 pr_crit("Unexpected close, not stopping watchdog!\n");
291                 wdt_ping();
292         }
293         expect_close = 0;
294         clear_bit(0, &wdt_is_open);
295         return 0;
296 }
297
298 /*
299  *      Notifier for system down
300  */
301
302 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
303         void *unused)
304 {
305         if (code == SYS_DOWN || code == SYS_HALT)
306                 wdt_disable();  /* Turn the WDT off */
307
308         return NOTIFY_DONE;
309 }
310
311 /*
312  *      Kernel Interfaces
313  */
314
315 static const struct file_operations wdt_fops = {
316         .owner          = THIS_MODULE,
317         .llseek         = no_llseek,
318         .write          = wdt_write,
319         .unlocked_ioctl = wdt_ioctl,
320         .open           = wdt_open,
321         .release        = wdt_close,
322 };
323
324 static struct miscdevice wdt_miscdev = {
325         .minor = WATCHDOG_MINOR,
326         .name = "watchdog",
327         .fops = &wdt_fops,
328 };
329
330 /*
331  *      The WDT needs to learn about soft shutdowns in order to
332  *      turn the timebomb registers off.
333  */
334
335 static struct notifier_block wdt_notifier = {
336         .notifier_call = wdt_notify_sys,
337 };
338
339 static int __init wdt_init(void)
340 {
341         int ret;
342
343         pr_info("WDT driver for the Winbond(TM) W83697UG/UF Super I/O chip initialising\n");
344
345         if (wdt_set_heartbeat(timeout)) {
346                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
347                 pr_info("timeout value must be 1<=timeout<=255, using %d\n",
348                         WATCHDOG_TIMEOUT);
349         }
350
351         if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
352                 pr_err("I/O address 0x%04x already in use\n", wdt_io);
353                 ret = -EIO;
354                 goto out;
355         }
356
357         ret = w83697ug_init();
358         if (ret != 0)
359                 goto unreg_regions;
360
361         ret = register_reboot_notifier(&wdt_notifier);
362         if (ret != 0) {
363                 pr_err("cannot register reboot notifier (err=%d)\n", ret);
364                 goto unreg_regions;
365         }
366
367         ret = misc_register(&wdt_miscdev);
368         if (ret != 0) {
369                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
370                        WATCHDOG_MINOR, ret);
371                 goto unreg_reboot;
372         }
373
374         pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
375                 timeout, nowayout);
376
377 out:
378         return ret;
379 unreg_reboot:
380         unregister_reboot_notifier(&wdt_notifier);
381 unreg_regions:
382         release_region(wdt_io, 1);
383         goto out;
384 }
385
386 static void __exit wdt_exit(void)
387 {
388         misc_deregister(&wdt_miscdev);
389         unregister_reboot_notifier(&wdt_notifier);
390         release_region(wdt_io, 1);
391 }
392
393 module_init(wdt_init);
394 module_exit(wdt_exit);
395
396 MODULE_LICENSE("GPL");
397 MODULE_AUTHOR("Flemming Frandsen <ff@nrvissing.net>");
398 MODULE_DESCRIPTION("w83697ug/uf WDT driver");
399 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);