watchdog: nowayout is bool
[linux-2.6.git] / drivers / watchdog / w83697hf_wdt.c
1 /*
2  *      w83697hf/hg WDT driver
3  *
4  *      (c) Copyright 2006 Samuel Tardieu <sam@rfc1149.net>
5  *      (c) Copyright 2006 Marcus Junker <junker@anduras.de>
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 2003 Pádraig Brady <P@draigBrady.com>
12  *
13  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
14  *
15  *      (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
16  *                                              All Rights Reserved.
17  *
18  *      This program is free software; you can redistribute it and/or
19  *      modify it under the terms of the GNU General Public License
20  *      as published by the Free Software Foundation; either version
21  *      2 of the License, or (at your option) any later version.
22  *
23  *      Neither Marcus Junker nor ANDURAS AG admit liability nor provide
24  *      warranty for any of this software. This material is provided
25  *      "AS-IS" and at no charge.
26  */
27
28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29
30 #include <linux/module.h>
31 #include <linux/moduleparam.h>
32 #include <linux/types.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 #include <asm/system.h>
45
46 #define WATCHDOG_NAME "w83697hf/hg WDT"
47 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
48 #define WATCHDOG_EARLY_DISABLE 1        /* Disable until userland kicks in */
49
50 static unsigned long wdt_is_open;
51 static char expect_close;
52 static DEFINE_SPINLOCK(io_lock);
53
54 /* You must set this - there is no sane way to probe for this board. */
55 static int wdt_io = 0x2e;
56 module_param(wdt_io, int, 0);
57 MODULE_PARM_DESC(wdt_io,
58                 "w83697hf/hg WDT io port (default 0x2e, 0 = autodetect)");
59
60 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
61 module_param(timeout, int, 0);
62 MODULE_PARM_DESC(timeout,
63         "Watchdog timeout in seconds. 1<= timeout <=255 (default="
64                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
65
66 static bool nowayout = WATCHDOG_NOWAYOUT;
67 module_param(nowayout, bool, 0);
68 MODULE_PARM_DESC(nowayout,
69         "Watchdog cannot be stopped once started (default="
70                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
71
72 static int early_disable = WATCHDOG_EARLY_DISABLE;
73 module_param(early_disable, int, 0);
74 MODULE_PARM_DESC(early_disable,
75         "Watchdog gets disabled at boot time (default="
76                                 __MODULE_STRING(WATCHDOG_EARLY_DISABLE) ")");
77
78 /*
79  *      Kernel methods.
80  */
81
82 #define W83697HF_EFER (wdt_io + 0)  /* Extended Function Enable Register */
83 #define W83697HF_EFIR (wdt_io + 0)  /* Extended Function Index Register
84                                                         (same as EFER) */
85 #define W83697HF_EFDR (wdt_io + 1)  /* Extended Function Data Register */
86
87 static inline void w83697hf_unlock(void)
88 {
89         outb_p(0x87, W83697HF_EFER);    /* Enter extended function mode */
90         outb_p(0x87, W83697HF_EFER);    /* Again according to manual */
91 }
92
93 static inline void w83697hf_lock(void)
94 {
95         outb_p(0xAA, W83697HF_EFER);    /* Leave extended function mode */
96 }
97
98 /*
99  *      The three functions w83697hf_get_reg(), w83697hf_set_reg() and
100  *      w83697hf_write_timeout() must be called with the device unlocked.
101  */
102
103 static unsigned char w83697hf_get_reg(unsigned char reg)
104 {
105         outb_p(reg, W83697HF_EFIR);
106         return inb_p(W83697HF_EFDR);
107 }
108
109 static void w83697hf_set_reg(unsigned char reg, unsigned char data)
110 {
111         outb_p(reg, W83697HF_EFIR);
112         outb_p(data, W83697HF_EFDR);
113 }
114
115 static void w83697hf_write_timeout(int timeout)
116 {
117         /* Write Timeout counter to CRF4 */
118         w83697hf_set_reg(0xF4, timeout);
119 }
120
121 static void w83697hf_select_wdt(void)
122 {
123         w83697hf_unlock();
124         w83697hf_set_reg(0x07, 0x08);   /* Switch to logic device 8 (GPIO2) */
125 }
126
127 static inline void w83697hf_deselect_wdt(void)
128 {
129         w83697hf_lock();
130 }
131
132 static void w83697hf_init(void)
133 {
134         unsigned char bbuf;
135
136         w83697hf_select_wdt();
137
138         bbuf = w83697hf_get_reg(0x29);
139         bbuf &= ~0x60;
140         bbuf |= 0x20;
141
142         /* Set pin 119 to WDTO# mode (= CR29, WDT0) */
143         w83697hf_set_reg(0x29, bbuf);
144
145         bbuf = w83697hf_get_reg(0xF3);
146         bbuf &= ~0x04;
147         w83697hf_set_reg(0xF3, bbuf);   /* Count mode is seconds */
148
149         w83697hf_deselect_wdt();
150 }
151
152 static void wdt_ping(void)
153 {
154         spin_lock(&io_lock);
155         w83697hf_select_wdt();
156
157         w83697hf_write_timeout(timeout);
158
159         w83697hf_deselect_wdt();
160         spin_unlock(&io_lock);
161 }
162
163 static void wdt_enable(void)
164 {
165         spin_lock(&io_lock);
166         w83697hf_select_wdt();
167
168         w83697hf_write_timeout(timeout);
169         w83697hf_set_reg(0x30, 1);      /* Enable timer */
170
171         w83697hf_deselect_wdt();
172         spin_unlock(&io_lock);
173 }
174
175 static void wdt_disable(void)
176 {
177         spin_lock(&io_lock);
178         w83697hf_select_wdt();
179
180         w83697hf_set_reg(0x30, 0);      /* Disable timer */
181         w83697hf_write_timeout(0);
182
183         w83697hf_deselect_wdt();
184         spin_unlock(&io_lock);
185 }
186
187 static unsigned char wdt_running(void)
188 {
189         unsigned char t;
190
191         spin_lock(&io_lock);
192         w83697hf_select_wdt();
193
194         t = w83697hf_get_reg(0xF4);     /* Read timer */
195
196         w83697hf_deselect_wdt();
197         spin_unlock(&io_lock);
198
199         return t;
200 }
201
202 static int wdt_set_heartbeat(int t)
203 {
204         if (t < 1 || t > 255)
205                 return -EINVAL;
206
207         timeout = t;
208         return 0;
209 }
210
211 static ssize_t wdt_write(struct file *file, const char __user *buf,
212                                                 size_t count, loff_t *ppos)
213 {
214         if (count) {
215                 if (!nowayout) {
216                         size_t i;
217
218                         expect_close = 0;
219
220                         for (i = 0; i != count; i++) {
221                                 char c;
222                                 if (get_user(c, buf + i))
223                                         return -EFAULT;
224                                 if (c == 'V')
225                                         expect_close = 42;
226                         }
227                 }
228                 wdt_ping();
229         }
230         return count;
231 }
232
233 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
234 {
235         void __user *argp = (void __user *)arg;
236         int __user *p = argp;
237         int new_timeout;
238         static const struct watchdog_info ident = {
239                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
240                                                         | WDIOF_MAGICCLOSE,
241                 .firmware_version = 1,
242                 .identity = "W83697HF WDT",
243         };
244
245         switch (cmd) {
246         case WDIOC_GETSUPPORT:
247                 if (copy_to_user(argp, &ident, sizeof(ident)))
248                         return -EFAULT;
249                 break;
250
251         case WDIOC_GETSTATUS:
252         case WDIOC_GETBOOTSTATUS:
253                 return put_user(0, p);
254
255         case WDIOC_SETOPTIONS:
256         {
257                 int options, retval = -EINVAL;
258
259                 if (get_user(options, p))
260                         return -EFAULT;
261
262                 if (options & WDIOS_DISABLECARD) {
263                         wdt_disable();
264                         retval = 0;
265                 }
266
267                 if (options & WDIOS_ENABLECARD) {
268                         wdt_enable();
269                         retval = 0;
270                 }
271
272                 return retval;
273         }
274
275         case WDIOC_KEEPALIVE:
276                 wdt_ping();
277                 break;
278
279         case WDIOC_SETTIMEOUT:
280                 if (get_user(new_timeout, p))
281                         return -EFAULT;
282                 if (wdt_set_heartbeat(new_timeout))
283                         return -EINVAL;
284                 wdt_ping();
285                 /* Fall */
286
287         case WDIOC_GETTIMEOUT:
288                 return put_user(timeout, p);
289
290         default:
291                 return -ENOTTY;
292         }
293         return 0;
294 }
295
296 static int wdt_open(struct inode *inode, struct file *file)
297 {
298         if (test_and_set_bit(0, &wdt_is_open))
299                 return -EBUSY;
300         /*
301          *      Activate
302          */
303
304         wdt_enable();
305         return nonseekable_open(inode, file);
306 }
307
308 static int wdt_close(struct inode *inode, struct file *file)
309 {
310         if (expect_close == 42)
311                 wdt_disable();
312         else {
313                 pr_crit("Unexpected close, not stopping watchdog!\n");
314                 wdt_ping();
315         }
316         expect_close = 0;
317         clear_bit(0, &wdt_is_open);
318         return 0;
319 }
320
321 /*
322  *      Notifier for system down
323  */
324
325 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
326         void *unused)
327 {
328         if (code == SYS_DOWN || code == SYS_HALT)
329                 wdt_disable();  /* Turn the WDT off */
330
331         return NOTIFY_DONE;
332 }
333
334 /*
335  *      Kernel Interfaces
336  */
337
338 static const struct file_operations wdt_fops = {
339         .owner          = THIS_MODULE,
340         .llseek         = no_llseek,
341         .write          = wdt_write,
342         .unlocked_ioctl = wdt_ioctl,
343         .open           = wdt_open,
344         .release        = wdt_close,
345 };
346
347 static struct miscdevice wdt_miscdev = {
348         .minor = WATCHDOG_MINOR,
349         .name = "watchdog",
350         .fops = &wdt_fops,
351 };
352
353 /*
354  *      The WDT needs to learn about soft shutdowns in order to
355  *      turn the timebomb registers off.
356  */
357
358 static struct notifier_block wdt_notifier = {
359         .notifier_call = wdt_notify_sys,
360 };
361
362 static int w83697hf_check_wdt(void)
363 {
364         if (!request_region(wdt_io, 2, WATCHDOG_NAME)) {
365                 pr_err("I/O address 0x%x already in use\n", wdt_io);
366                 return -EIO;
367         }
368
369         pr_debug("Looking for watchdog at address 0x%x\n", wdt_io);
370         w83697hf_unlock();
371         if (w83697hf_get_reg(0x20) == 0x60) {
372                 pr_info("watchdog found at address 0x%x\n", wdt_io);
373                 w83697hf_lock();
374                 return 0;
375         }
376         /* Reprotect in case it was a compatible device */
377         w83697hf_lock();
378
379         pr_info("watchdog not found at address 0x%x\n", wdt_io);
380         release_region(wdt_io, 2);
381         return -EIO;
382 }
383
384 static int w83697hf_ioports[] = { 0x2e, 0x4e, 0x00 };
385
386 static int __init wdt_init(void)
387 {
388         int ret, i, found = 0;
389
390         pr_info("WDT driver for W83697HF/HG initializing\n");
391
392         if (wdt_io == 0) {
393                 /* we will autodetect the W83697HF/HG watchdog */
394                 for (i = 0; ((!found) && (w83697hf_ioports[i] != 0)); i++) {
395                         wdt_io = w83697hf_ioports[i];
396                         if (!w83697hf_check_wdt())
397                                 found++;
398                 }
399         } else {
400                 if (!w83697hf_check_wdt())
401                         found++;
402         }
403
404         if (!found) {
405                 pr_err("No W83697HF/HG could be found\n");
406                 ret = -EIO;
407                 goto out;
408         }
409
410         w83697hf_init();
411         if (early_disable) {
412                 if (wdt_running())
413                         pr_warn("Stopping previously enabled watchdog until userland kicks in\n");
414                 wdt_disable();
415         }
416
417         if (wdt_set_heartbeat(timeout)) {
418                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
419                 pr_info("timeout value must be 1 <= timeout <= 255, using %d\n",
420                         WATCHDOG_TIMEOUT);
421         }
422
423         ret = register_reboot_notifier(&wdt_notifier);
424         if (ret != 0) {
425                 pr_err("cannot register reboot notifier (err=%d)\n", ret);
426                 goto unreg_regions;
427         }
428
429         ret = misc_register(&wdt_miscdev);
430         if (ret != 0) {
431                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
432                        WATCHDOG_MINOR, ret);
433                 goto unreg_reboot;
434         }
435
436         pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
437                 timeout, nowayout);
438
439 out:
440         return ret;
441 unreg_reboot:
442         unregister_reboot_notifier(&wdt_notifier);
443 unreg_regions:
444         release_region(wdt_io, 2);
445         goto out;
446 }
447
448 static void __exit wdt_exit(void)
449 {
450         misc_deregister(&wdt_miscdev);
451         unregister_reboot_notifier(&wdt_notifier);
452         release_region(wdt_io, 2);
453 }
454
455 module_init(wdt_init);
456 module_exit(wdt_exit);
457
458 MODULE_LICENSE("GPL");
459 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>, "
460                 "Samuel Tardieu <sam@rfc1149.net>");
461 MODULE_DESCRIPTION("w83697hf/hg WDT driver");
462 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);