Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
[sfrench/cifs-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 #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 #include <linux/io.h>
40 #include <linux/uaccess.h>
41
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 #define WATCHDOG_EARLY_DISABLE 1        /* Disable until userland kicks in */
48
49 static unsigned long wdt_is_open;
50 static char expect_close;
51 static DEFINE_SPINLOCK(io_lock);
52
53 /* You must set this - there is no sane way to probe for this board. */
54 static int wdt_io = 0x2e;
55 module_param(wdt_io, int, 0);
56 MODULE_PARM_DESC(wdt_io,
57                 "w83697hf/hg WDT io port (default 0x2e, 0 = autodetect)");
58
59 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
60 module_param(timeout, int, 0);
61 MODULE_PARM_DESC(timeout,
62         "Watchdog timeout in seconds. 1<= timeout <=255 (default="
63                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
64
65 static int nowayout = WATCHDOG_NOWAYOUT;
66 module_param(nowayout, int, 0);
67 MODULE_PARM_DESC(nowayout,
68         "Watchdog cannot be stopped once started (default="
69                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
70
71 static int early_disable = WATCHDOG_EARLY_DISABLE;
72 module_param(early_disable, int, 0);
73 MODULE_PARM_DESC(early_disable,
74         "Watchdog gets disabled at boot time (default="
75                                 __MODULE_STRING(WATCHDOG_EARLY_DISABLE) ")");
76
77 /*
78  *      Kernel methods.
79  */
80
81 #define W83697HF_EFER (wdt_io + 0)  /* Extended Function Enable Register */
82 #define W83697HF_EFIR (wdt_io + 0)  /* Extended Function Index Register
83                                                         (same as EFER) */
84 #define W83697HF_EFDR (wdt_io + 1)  /* Extended Function Data Register */
85
86 static inline void w83697hf_unlock(void)
87 {
88         outb_p(0x87, W83697HF_EFER);    /* Enter extended function mode */
89         outb_p(0x87, W83697HF_EFER);    /* Again according to manual */
90 }
91
92 static inline void w83697hf_lock(void)
93 {
94         outb_p(0xAA, W83697HF_EFER);    /* Leave extended function mode */
95 }
96
97 /*
98  *      The three functions w83697hf_get_reg(), w83697hf_set_reg() and
99  *      w83697hf_write_timeout() must be called with the device unlocked.
100  */
101
102 static unsigned char w83697hf_get_reg(unsigned char reg)
103 {
104         outb_p(reg, W83697HF_EFIR);
105         return inb_p(W83697HF_EFDR);
106 }
107
108 static void w83697hf_set_reg(unsigned char reg, unsigned char data)
109 {
110         outb_p(reg, W83697HF_EFIR);
111         outb_p(data, W83697HF_EFDR);
112 }
113
114 static void w83697hf_write_timeout(int timeout)
115 {
116         /* Write Timeout counter to CRF4 */
117         w83697hf_set_reg(0xF4, timeout);
118 }
119
120 static void w83697hf_select_wdt(void)
121 {
122         w83697hf_unlock();
123         w83697hf_set_reg(0x07, 0x08);   /* Switch to logic device 8 (GPIO2) */
124 }
125
126 static inline void w83697hf_deselect_wdt(void)
127 {
128         w83697hf_lock();
129 }
130
131 static void w83697hf_init(void)
132 {
133         unsigned char bbuf;
134
135         w83697hf_select_wdt();
136
137         bbuf = w83697hf_get_reg(0x29);
138         bbuf &= ~0x60;
139         bbuf |= 0x20;
140
141         /* Set pin 119 to WDTO# mode (= CR29, WDT0) */
142         w83697hf_set_reg(0x29, bbuf);
143
144         bbuf = w83697hf_get_reg(0xF3);
145         bbuf &= ~0x04;
146         w83697hf_set_reg(0xF3, bbuf);   /* Count mode is seconds */
147
148         w83697hf_deselect_wdt();
149 }
150
151 static void wdt_ping(void)
152 {
153         spin_lock(&io_lock);
154         w83697hf_select_wdt();
155
156         w83697hf_write_timeout(timeout);
157
158         w83697hf_deselect_wdt();
159         spin_unlock(&io_lock);
160 }
161
162 static void wdt_enable(void)
163 {
164         spin_lock(&io_lock);
165         w83697hf_select_wdt();
166
167         w83697hf_write_timeout(timeout);
168         w83697hf_set_reg(0x30, 1);      /* Enable timer */
169
170         w83697hf_deselect_wdt();
171         spin_unlock(&io_lock);
172 }
173
174 static void wdt_disable(void)
175 {
176         spin_lock(&io_lock);
177         w83697hf_select_wdt();
178
179         w83697hf_set_reg(0x30, 0);      /* Disable timer */
180         w83697hf_write_timeout(0);
181
182         w83697hf_deselect_wdt();
183         spin_unlock(&io_lock);
184 }
185
186 static unsigned char wdt_running(void)
187 {
188         unsigned char t;
189
190         spin_lock(&io_lock);
191         w83697hf_select_wdt();
192
193         t = w83697hf_get_reg(0xF4);     /* Read timer */
194
195         w83697hf_deselect_wdt();
196         spin_unlock(&io_lock);
197
198         return t;
199 }
200
201 static int wdt_set_heartbeat(int t)
202 {
203         if (t < 1 || t > 255)
204                 return -EINVAL;
205
206         timeout = t;
207         return 0;
208 }
209
210 static ssize_t wdt_write(struct file *file, const char __user *buf,
211                                                 size_t count, loff_t *ppos)
212 {
213         if (count) {
214                 if (!nowayout) {
215                         size_t i;
216
217                         expect_close = 0;
218
219                         for (i = 0; i != count; i++) {
220                                 char c;
221                                 if (get_user(c, buf + i))
222                                         return -EFAULT;
223                                 if (c == 'V')
224                                         expect_close = 42;
225                         }
226                 }
227                 wdt_ping();
228         }
229         return count;
230 }
231
232 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
233 {
234         void __user *argp = (void __user *)arg;
235         int __user *p = argp;
236         int new_timeout;
237         static const struct watchdog_info ident = {
238                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
239                                                         | WDIOF_MAGICCLOSE,
240                 .firmware_version = 1,
241                 .identity = "W83697HF WDT",
242         };
243
244         switch (cmd) {
245         case WDIOC_GETSUPPORT:
246                 if (copy_to_user(argp, &ident, sizeof(ident)))
247                         return -EFAULT;
248                 break;
249
250         case WDIOC_GETSTATUS:
251         case WDIOC_GETBOOTSTATUS:
252                 return put_user(0, 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         case WDIOC_KEEPALIVE:
275                 wdt_ping();
276                 break;
277
278         case WDIOC_SETTIMEOUT:
279                 if (get_user(new_timeout, p))
280                         return -EFAULT;
281                 if (wdt_set_heartbeat(new_timeout))
282                         return -EINVAL;
283                 wdt_ping();
284                 /* Fall */
285
286         case WDIOC_GETTIMEOUT:
287                 return put_user(timeout, p);
288
289         default:
290                 return -ENOTTY;
291         }
292         return 0;
293 }
294
295 static int wdt_open(struct inode *inode, struct file *file)
296 {
297         if (test_and_set_bit(0, &wdt_is_open))
298                 return -EBUSY;
299         /*
300          *      Activate
301          */
302
303         wdt_enable();
304         return nonseekable_open(inode, file);
305 }
306
307 static int wdt_close(struct inode *inode, struct file *file)
308 {
309         if (expect_close == 42)
310                 wdt_disable();
311         else {
312                 printk(KERN_CRIT PFX
313                         "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                 printk(KERN_ERR PFX
366                         "I/O address 0x%x already in use\n", wdt_io);
367                 return -EIO;
368         }
369
370         printk(KERN_DEBUG PFX
371                         "Looking for watchdog at address 0x%x\n", wdt_io);
372         w83697hf_unlock();
373         if (w83697hf_get_reg(0x20) == 0x60) {
374                 printk(KERN_INFO PFX
375                         "watchdog found at address 0x%x\n", wdt_io);
376                 w83697hf_lock();
377                 return 0;
378         }
379         /* Reprotect in case it was a compatible device */
380         w83697hf_lock();
381
382         printk(KERN_INFO PFX "watchdog not found at address 0x%x\n", wdt_io);
383         release_region(wdt_io, 2);
384         return -EIO;
385 }
386
387 static int w83697hf_ioports[] = { 0x2e, 0x4e, 0x00 };
388
389 static int __init wdt_init(void)
390 {
391         int ret, i, found = 0;
392
393         printk(KERN_INFO PFX "WDT driver for W83697HF/HG initializing\n");
394
395         if (wdt_io == 0) {
396                 /* we will autodetect the W83697HF/HG watchdog */
397                 for (i = 0; ((!found) && (w83697hf_ioports[i] != 0)); i++) {
398                         wdt_io = w83697hf_ioports[i];
399                         if (!w83697hf_check_wdt())
400                                 found++;
401                 }
402         } else {
403                 if (!w83697hf_check_wdt())
404                         found++;
405         }
406
407         if (!found) {
408                 printk(KERN_ERR PFX "No W83697HF/HG could be found\n");
409                 ret = -EIO;
410                 goto out;
411         }
412
413         w83697hf_init();
414         if (early_disable) {
415                 if (wdt_running())
416                         printk(KERN_WARNING PFX "Stopping previously enabled "
417                                         "watchdog until userland kicks in\n");
418                 wdt_disable();
419         }
420
421         if (wdt_set_heartbeat(timeout)) {
422                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
423                 printk(KERN_INFO PFX
424                      "timeout value must be 1 <= timeout <= 255, using %d\n",
425                                                         WATCHDOG_TIMEOUT);
426         }
427
428         ret = register_reboot_notifier(&wdt_notifier);
429         if (ret != 0) {
430                 printk(KERN_ERR PFX
431                         "cannot register reboot notifier (err=%d)\n", ret);
432                 goto unreg_regions;
433         }
434
435         ret = misc_register(&wdt_miscdev);
436         if (ret != 0) {
437                 printk(KERN_ERR PFX
438                         "cannot register miscdev on minor=%d (err=%d)\n",
439                                                 WATCHDOG_MINOR, ret);
440                 goto unreg_reboot;
441         }
442
443         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
444                 timeout, nowayout);
445
446 out:
447         return ret;
448 unreg_reboot:
449         unregister_reboot_notifier(&wdt_notifier);
450 unreg_regions:
451         release_region(wdt_io, 2);
452         goto out;
453 }
454
455 static void __exit wdt_exit(void)
456 {
457         misc_deregister(&wdt_miscdev);
458         unregister_reboot_notifier(&wdt_notifier);
459         release_region(wdt_io, 2);
460 }
461
462 module_init(wdt_init);
463 module_exit(wdt_exit);
464
465 MODULE_LICENSE("GPL");
466 MODULE_AUTHOR("Marcus Junker <junker@anduras.de>, "
467                 "Samuel Tardieu <sam@rfc1149.net>");
468 MODULE_DESCRIPTION("w83697hf/hg WDT driver");
469 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);