[PATCH] mark struct file_operations const 3
[linux-2.6.git] / drivers / char / 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@redhat.com>, All Rights Reserved.
16  *                              http://www.redhat.com
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 #include <linux/module.h>
29 #include <linux/moduleparam.h>
30 #include <linux/types.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
40 #include <asm/io.h>
41 #include <asm/uaccess.h>
42 #include <asm/system.h>
43
44 #define WATCHDOG_NAME "w83697hf/hg WDT"
45 #define PFX WATCHDOG_NAME ": "
46 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
47
48 static unsigned long wdt_is_open;
49 static char expect_close;
50 static spinlock_t io_lock;
51
52 /* You must set this - there is no sane way to probe for this board. */
53 static int wdt_io = 0x2e;
54 module_param(wdt_io, int, 0);
55 MODULE_PARM_DESC(wdt_io, "w83697hf/hg WDT io port (default 0x2e, 0 = autodetect)");
56
57 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
58 module_param(timeout, int, 0);
59 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=255, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
60
61 static int nowayout = WATCHDOG_NOWAYOUT;
62 module_param(nowayout, int, 0);
63 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
64
65 /*
66  *      Kernel methods.
67  */
68
69 #define W83697HF_EFER (wdt_io+0)        /* Extended Function Enable Register */
70 #define W83697HF_EFIR (wdt_io+0)        /* Extended Function Index Register (same as EFER) */
71 #define W83697HF_EFDR (wdt_io+1)        /* Extended Function Data Register */
72
73 static inline void
74 w83697hf_unlock(void)
75 {
76         outb_p(0x87, W83697HF_EFER);    /* Enter extended function mode */
77         outb_p(0x87, W83697HF_EFER);    /* Again according to manual */
78 }
79
80 static inline void
81 w83697hf_lock(void)
82 {
83         outb_p(0xAA, W83697HF_EFER);    /* Leave extended function mode */
84 }
85
86 /*
87  *      The three functions w83697hf_get_reg(), w83697hf_set_reg() and
88  *      w83697hf_write_timeout() must be called with the device unlocked.
89  */
90
91 static unsigned char
92 w83697hf_get_reg(unsigned char reg)
93 {
94         outb_p(reg, W83697HF_EFIR);
95         return inb_p(W83697HF_EFDR);
96 }
97
98 static void
99 w83697hf_set_reg(unsigned char reg, unsigned char data)
100 {
101         outb_p(reg, W83697HF_EFIR);
102         outb_p(data, W83697HF_EFDR);
103 }
104
105 static void
106 w83697hf_write_timeout(int timeout)
107 {
108         w83697hf_set_reg(0xF4, timeout);        /* Write Timeout counter to CRF4 */
109 }
110
111 static void
112 w83697hf_select_wdt(void)
113 {
114         w83697hf_unlock();
115         w83697hf_set_reg(0x07, 0x08);   /* Switch to logic device 8 (GPIO2) */
116 }
117
118 static inline void
119 w83697hf_deselect_wdt(void)
120 {
121         w83697hf_lock();
122 }
123
124 static void
125 w83697hf_init(void)
126 {
127         unsigned char bbuf;
128
129         w83697hf_select_wdt();
130
131         bbuf = w83697hf_get_reg(0x29);
132         bbuf &= ~0x60;
133         bbuf |= 0x20;
134         w83697hf_set_reg(0x29, bbuf);   /* Set pin 119 to WDTO# mode (= CR29, WDT0) */
135
136         bbuf = w83697hf_get_reg(0xF3);
137         bbuf &= ~0x04;
138         w83697hf_set_reg(0xF3, bbuf);   /* Count mode is seconds */
139
140         w83697hf_deselect_wdt();
141 }
142
143 static int
144 wdt_ping(void)
145 {
146         spin_lock(&io_lock);
147         w83697hf_select_wdt();
148
149         w83697hf_write_timeout(timeout);
150
151         w83697hf_deselect_wdt();
152         spin_unlock(&io_lock);
153         return 0;
154 }
155
156 static int
157 wdt_enable(void)
158 {
159         spin_lock(&io_lock);
160         w83697hf_select_wdt();
161
162         w83697hf_write_timeout(timeout);
163         w83697hf_set_reg(0x30, 1);      /* Enable timer */
164
165         w83697hf_deselect_wdt();
166         spin_unlock(&io_lock);
167         return 0;
168 }
169
170 static int
171 wdt_disable(void)
172 {
173         spin_lock(&io_lock);
174         w83697hf_select_wdt();
175
176         w83697hf_set_reg(0x30, 0);      /* Disable timer */
177         w83697hf_write_timeout(0);
178
179         w83697hf_deselect_wdt();
180         spin_unlock(&io_lock);
181         return 0;
182 }
183
184 static int
185 wdt_set_heartbeat(int t)
186 {
187         if ((t < 1) || (t > 255))
188                 return -EINVAL;
189
190         timeout = t;
191         return 0;
192 }
193
194 static ssize_t
195 wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
196 {
197         if (count) {
198                 if (!nowayout) {
199                         size_t i;
200
201                         expect_close = 0;
202
203                         for (i = 0; i != count; i++) {
204                                 char c;
205                                 if (get_user(c, buf+i))
206                                         return -EFAULT;
207                                 if (c == 'V')
208                                         expect_close = 42;
209                         }
210                 }
211                 wdt_ping();
212         }
213         return count;
214 }
215
216 static int
217 wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
218           unsigned long arg)
219 {
220         void __user *argp = (void __user *)arg;
221         int __user *p = argp;
222         int new_timeout;
223         static struct watchdog_info ident = {
224                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
225                 .firmware_version = 1,
226                 .identity = "W83697HF WDT",
227         };
228
229         switch (cmd) {
230         case WDIOC_GETSUPPORT:
231                 if (copy_to_user(argp, &ident, sizeof(ident)))
232                         return -EFAULT;
233                 break;
234
235         case WDIOC_GETSTATUS:
236         case WDIOC_GETBOOTSTATUS:
237                 return put_user(0, p);
238
239         case WDIOC_KEEPALIVE:
240                 wdt_ping();
241                 break;
242
243         case WDIOC_SETTIMEOUT:
244                 if (get_user(new_timeout, p))
245                         return -EFAULT;
246                 if (wdt_set_heartbeat(new_timeout))
247                         return -EINVAL;
248                 wdt_ping();
249                 /* Fall */
250
251         case WDIOC_GETTIMEOUT:
252                 return put_user(timeout, p);
253
254         case WDIOC_SETOPTIONS:
255         {
256                 int options, retval = -EINVAL;
257
258                 if (get_user(options, p))
259                         return -EFAULT;
260
261                 if (options & WDIOS_DISABLECARD) {
262                         wdt_disable();
263                         retval = 0;
264                 }
265
266                 if (options & WDIOS_ENABLECARD) {
267                         wdt_enable();
268                         retval = 0;
269                 }
270
271                 return retval;
272         }
273
274         default:
275                 return -ENOTTY;
276         }
277         return 0;
278 }
279
280 static int
281 wdt_open(struct inode *inode, struct file *file)
282 {
283         if (test_and_set_bit(0, &wdt_is_open))
284                 return -EBUSY;
285         /*
286          *      Activate
287          */
288
289         wdt_enable();
290         return nonseekable_open(inode, file);
291 }
292
293 static int
294 wdt_close(struct inode *inode, struct file *file)
295 {
296         if (expect_close == 42) {
297                 wdt_disable();
298         } else {
299                 printk (KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
300                 wdt_ping();
301         }
302         expect_close = 0;
303         clear_bit(0, &wdt_is_open);
304         return 0;
305 }
306
307 /*
308  *      Notifier for system down
309  */
310
311 static int
312 wdt_notify_sys(struct notifier_block *this, unsigned long code,
313         void *unused)
314 {
315         if (code == SYS_DOWN || code == SYS_HALT) {
316                 /* Turn the WDT off */
317                 wdt_disable();
318         }
319         return NOTIFY_DONE;
320 }
321
322 /*
323  *      Kernel Interfaces
324  */
325
326 static const struct file_operations wdt_fops = {
327         .owner          = THIS_MODULE,
328         .llseek         = no_llseek,
329         .write          = wdt_write,
330         .ioctl          = wdt_ioctl,
331         .open           = wdt_open,
332         .release        = wdt_close,
333 };
334
335 static struct miscdevice wdt_miscdev = {
336         .minor = WATCHDOG_MINOR,
337         .name = "watchdog",
338         .fops = &wdt_fops,
339 };
340
341 /*
342  *      The WDT needs to learn about soft shutdowns in order to
343  *      turn the timebomb registers off.
344  */
345
346 static struct notifier_block wdt_notifier = {
347         .notifier_call = wdt_notify_sys,
348 };
349
350 static int
351 w83697hf_check_wdt(void)
352 {
353         if (!request_region(wdt_io, 2, WATCHDOG_NAME)) {
354                 printk (KERN_ERR PFX "I/O address 0x%x already in use\n", wdt_io);
355                 return -EIO;
356         }
357
358         printk (KERN_DEBUG PFX "Looking for watchdog at address 0x%x\n", wdt_io);
359         w83697hf_unlock();
360         if (w83697hf_get_reg(0x20) == 0x60) {
361                 printk (KERN_INFO PFX "watchdog found at address 0x%x\n", wdt_io);
362                 w83697hf_lock();
363                 return 0;
364         }
365         w83697hf_lock();        /* Reprotect in case it was a compatible device */
366
367         printk (KERN_INFO PFX "watchdog not found at address 0x%x\n", wdt_io);
368         release_region(wdt_io, 2);
369         return -EIO;
370 }
371
372 static int w83697hf_ioports[] = { 0x2e, 0x4e, 0x00 };
373
374 static int __init
375 wdt_init(void)
376 {
377         int ret, i, found = 0;
378
379         spin_lock_init(&io_lock);
380
381         printk (KERN_INFO PFX "WDT driver for W83697HF/HG initializing\n");
382
383         if (wdt_io == 0) {
384                 /* we will autodetect the W83697HF/HG watchdog */
385                 for (i = 0; ((!found) && (w83697hf_ioports[i] != 0)); i++) {
386                         wdt_io = w83697hf_ioports[i];
387                         if (!w83697hf_check_wdt())
388                                 found++;
389                 }
390         } else {
391                 if (!w83697hf_check_wdt())
392                         found++;
393         }
394
395         if (!found) {
396                 printk (KERN_ERR PFX "No W83697HF/HG could be found\n");
397                 ret = -EIO;
398                 goto out;
399         }
400
401         w83697hf_init();
402         wdt_disable();  /* Disable watchdog until first use */
403
404         if (wdt_set_heartbeat(timeout)) {
405                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
406                 printk (KERN_INFO PFX "timeout value must be 1<=timeout<=255, using %d\n",
407                         WATCHDOG_TIMEOUT);
408         }
409
410         ret = register_reboot_notifier(&wdt_notifier);
411         if (ret != 0) {
412                 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
413                         ret);
414                 goto unreg_regions;
415         }
416
417         ret = misc_register(&wdt_miscdev);
418         if (ret != 0) {
419                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
420                         WATCHDOG_MINOR, ret);
421                 goto unreg_reboot;
422         }
423
424         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
425                 timeout, nowayout);
426
427 out:
428         return ret;
429 unreg_reboot:
430         unregister_reboot_notifier(&wdt_notifier);
431 unreg_regions:
432         release_region(wdt_io, 2);
433         goto out;
434 }
435
436 static void __exit
437 wdt_exit(void)
438 {
439         misc_deregister(&wdt_miscdev);
440         unregister_reboot_notifier(&wdt_notifier);
441         release_region(wdt_io, 2);
442 }
443
444 module_init(wdt_init);
445 module_exit(wdt_exit);
446
447 MODULE_LICENSE("GPL");
448 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>, Samuel Tardieu <sam@rfc1149.net>");
449 MODULE_DESCRIPTION("w83697hf/hg WDT driver");
450 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);