6aa914e5caf5bef6b9fd9b93d3a0c671b25722d4
[linux-2.6.git] / drivers / watchdog / ib700wdt.c
1 /*
2  *      IB700 Single Board Computer WDT driver
3  *
4  *      (c) Copyright 2001 Charles Howes <chowes@vsol.net>
5  *
6  *      Based on advantechwdt.c which is based on acquirewdt.c which
7  *      is based on wdt.c.
8  *
9  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
10  *
11  *      Based on acquirewdt.c which is based on wdt.c.
12  *      Original copyright messages:
13  *
14  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
15  *                              http://www.redhat.com
16  *
17  *      This program is free software; you can redistribute it and/or
18  *      modify it under the terms of the GNU General Public License
19  *      as published by the Free Software Foundation; either version
20  *      2 of the License, or (at your option) any later version.
21  *
22  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
23  *      warranty for any of this software. This material is provided
24  *      "AS-IS" and at no charge.
25  *
26  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
27  *
28  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
29  *           Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
30  *           Added timeout module option to override default
31  *
32  */
33
34 #include <linux/module.h>
35 #include <linux/types.h>
36 #include <linux/miscdevice.h>
37 #include <linux/watchdog.h>
38 #include <linux/ioport.h>
39 #include <linux/fs.h>
40 #include <linux/init.h>
41 #include <linux/spinlock.h>
42 #include <linux/moduleparam.h>
43 #include <linux/platform_device.h>
44 #include <linux/io.h>
45 #include <linux/uaccess.h>
46
47 #include <asm/system.h>
48
49 static struct platform_device *ibwdt_platform_device;
50 static unsigned long ibwdt_is_open;
51 static DEFINE_SPINLOCK(ibwdt_lock);
52 static char expect_close;
53
54 /* Module information */
55 #define DRV_NAME "ib700wdt"
56 #define PFX DRV_NAME ": "
57
58 /*
59  *
60  * Watchdog Timer Configuration
61  *
62  * The function of the watchdog timer is to reset the system
63  * automatically and is defined at I/O port 0443H.  To enable the
64  * watchdog timer and allow the system to reset, write I/O port 0443H.
65  * To disable the timer, write I/O port 0441H for the system to stop the
66  * watchdog function.  The timer has a tolerance of 20% for its
67  * intervals.
68  *
69  * The following describes how the timer should be programmed.
70  *
71  * Enabling Watchdog:
72  * MOV AX,000FH (Choose the values from 0 to F)
73  * MOV DX,0443H
74  * OUT DX,AX
75  *
76  * Disabling Watchdog:
77  * MOV AX,000FH (Any value is fine.)
78  * MOV DX,0441H
79  * OUT DX,AX
80  *
81  * Watchdog timer control table:
82  * Level   Value  Time/sec | Level Value Time/sec
83  *   1       F       0     |   9     7      16
84  *   2       E       2     |   10    6      18
85  *   3       D       4     |   11    5      20
86  *   4       C       6     |   12    4      22
87  *   5       B       8     |   13    3      24
88  *   6       A       10    |   14    2      26
89  *   7       9       12    |   15    1      28
90  *   8       8       14    |   16    0      30
91  *
92  */
93
94 static int wd_times[] = {
95         30,     /* 0x0 */
96         28,     /* 0x1 */
97         26,     /* 0x2 */
98         24,     /* 0x3 */
99         22,     /* 0x4 */
100         20,     /* 0x5 */
101         18,     /* 0x6 */
102         16,     /* 0x7 */
103         14,     /* 0x8 */
104         12,     /* 0x9 */
105         10,     /* 0xA */
106         8,      /* 0xB */
107         6,      /* 0xC */
108         4,      /* 0xD */
109         2,      /* 0xE */
110         0,      /* 0xF */
111 };
112
113 #define WDT_STOP 0x441
114 #define WDT_START 0x443
115
116 /* Default timeout */
117 #define WD_TIMO 0               /* 30 seconds +/- 20%, from table */
118
119 static int wd_margin = WD_TIMO;
120
121 static int nowayout = WATCHDOG_NOWAYOUT;
122 module_param(nowayout, int, 0);
123 MODULE_PARM_DESC(nowayout,
124                 "Watchdog cannot be stopped once started (default="
125                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
126
127
128 /*
129  *      Watchdog Operations
130  */
131
132 static void
133 ibwdt_ping(void)
134 {
135         spin_lock(&ibwdt_lock);
136
137         /* Write a watchdog value */
138         outb_p(wd_margin, WDT_START);
139
140         spin_unlock(&ibwdt_lock);
141 }
142
143 static void
144 ibwdt_disable(void)
145 {
146         spin_lock(&ibwdt_lock);
147         outb_p(0, WDT_STOP);
148         spin_unlock(&ibwdt_lock);
149 }
150
151 static int
152 ibwdt_set_heartbeat(int t)
153 {
154         int i;
155
156         if ((t < 0) || (t > 30))
157                 return -EINVAL;
158
159         for (i = 0x0F; i > -1; i--)
160                 if (wd_times[i] > t)
161                         break;
162         wd_margin = i;
163         return 0;
164 }
165
166 /*
167  *      /dev/watchdog handling
168  */
169
170 static ssize_t ibwdt_write(struct file *file, const char __user *buf,
171                                                 size_t count, loff_t *ppos)
172 {
173         if (count) {
174                 if (!nowayout) {
175                         size_t i;
176
177                         /* In case it was set long ago */
178                         expect_close = 0;
179
180                         for (i = 0; i != count; i++) {
181                                 char c;
182                                 if (get_user(c, buf + i))
183                                         return -EFAULT;
184                                 if (c == 'V')
185                                         expect_close = 42;
186                         }
187                 }
188                 ibwdt_ping();
189         }
190         return count;
191 }
192
193 static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
194 {
195         int new_margin;
196         void __user *argp = (void __user *)arg;
197         int __user *p = argp;
198
199         static struct watchdog_info ident = {
200                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
201                                                         | WDIOF_MAGICCLOSE,
202                 .firmware_version = 1,
203                 .identity = "IB700 WDT",
204         };
205
206         switch (cmd) {
207         case WDIOC_GETSUPPORT:
208                 if (copy_to_user(argp, &ident, sizeof(ident)))
209                         return -EFAULT;
210                 break;
211
212         case WDIOC_GETSTATUS:
213         case WDIOC_GETBOOTSTATUS:
214                 return put_user(0, p);
215
216         case WDIOC_SETOPTIONS:
217         {
218                 int options, retval = -EINVAL;
219
220                 if (get_user(options, p))
221                         return -EFAULT;
222
223                 if (options & WDIOS_DISABLECARD) {
224                         ibwdt_disable();
225                         retval = 0;
226                 }
227                 if (options & WDIOS_ENABLECARD) {
228                         ibwdt_ping();
229                         retval = 0;
230                 }
231                 return retval;
232         }
233         case WDIOC_KEEPALIVE:
234                 ibwdt_ping();
235                 break;
236
237         case WDIOC_SETTIMEOUT:
238                 if (get_user(new_margin, p))
239                         return -EFAULT;
240                 if (ibwdt_set_heartbeat(new_margin))
241                         return -EINVAL;
242                 ibwdt_ping();
243                 /* Fall */
244
245         case WDIOC_GETTIMEOUT:
246                 return put_user(wd_times[wd_margin], p);
247
248         default:
249                 return -ENOTTY;
250         }
251         return 0;
252 }
253
254 static int ibwdt_open(struct inode *inode, struct file *file)
255 {
256         if (test_and_set_bit(0, &ibwdt_is_open))
257                 return -EBUSY;
258         if (nowayout)
259                 __module_get(THIS_MODULE);
260
261         /* Activate */
262         ibwdt_ping();
263         return nonseekable_open(inode, file);
264 }
265
266 static int
267 ibwdt_close(struct inode *inode, struct file *file)
268 {
269         if (expect_close == 42) {
270                 ibwdt_disable();
271         } else {
272                 printk(KERN_CRIT PFX
273                      "WDT device closed unexpectedly.  WDT will not stop!\n");
274                 ibwdt_ping();
275         }
276         clear_bit(0, &ibwdt_is_open);
277         expect_close = 0;
278         return 0;
279 }
280
281 /*
282  *      Kernel Interfaces
283  */
284
285 static const struct file_operations ibwdt_fops = {
286         .owner          = THIS_MODULE,
287         .llseek         = no_llseek,
288         .write          = ibwdt_write,
289         .unlocked_ioctl = ibwdt_ioctl,
290         .open           = ibwdt_open,
291         .release        = ibwdt_close,
292 };
293
294 static struct miscdevice ibwdt_miscdev = {
295         .minor = WATCHDOG_MINOR,
296         .name = "watchdog",
297         .fops = &ibwdt_fops,
298 };
299
300 /*
301  *      Init & exit routines
302  */
303
304 static int __devinit ibwdt_probe(struct platform_device *dev)
305 {
306         int res;
307
308 #if WDT_START != WDT_STOP
309         if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
310                 printk(KERN_ERR PFX "STOP method I/O %X is not available.\n",
311                                                                 WDT_STOP);
312                 res = -EIO;
313                 goto out_nostopreg;
314         }
315 #endif
316
317         if (!request_region(WDT_START, 1, "IB700 WDT")) {
318                 printk(KERN_ERR PFX "START method I/O %X is not available.\n",
319                                                                 WDT_START);
320                 res = -EIO;
321                 goto out_nostartreg;
322         }
323
324         res = misc_register(&ibwdt_miscdev);
325         if (res) {
326                 printk(KERN_ERR PFX "failed to register misc device\n");
327                 goto out_nomisc;
328         }
329         return 0;
330
331 out_nomisc:
332         release_region(WDT_START, 1);
333 out_nostartreg:
334 #if WDT_START != WDT_STOP
335         release_region(WDT_STOP, 1);
336 #endif
337 out_nostopreg:
338         return res;
339 }
340
341 static int __devexit ibwdt_remove(struct platform_device *dev)
342 {
343         misc_deregister(&ibwdt_miscdev);
344         release_region(WDT_START, 1);
345 #if WDT_START != WDT_STOP
346         release_region(WDT_STOP, 1);
347 #endif
348         return 0;
349 }
350
351 static void ibwdt_shutdown(struct platform_device *dev)
352 {
353         /* Turn the WDT off if we have a soft shutdown */
354         ibwdt_disable();
355 }
356
357 static struct platform_driver ibwdt_driver = {
358         .probe          = ibwdt_probe,
359         .remove         = __devexit_p(ibwdt_remove),
360         .shutdown       = ibwdt_shutdown,
361         .driver         = {
362                 .owner  = THIS_MODULE,
363                 .name   = DRV_NAME,
364         },
365 };
366
367 static int __init ibwdt_init(void)
368 {
369         int err;
370
371         printk(KERN_INFO PFX
372                 "WDT driver for IB700 single board computer initialising.\n");
373
374         err = platform_driver_register(&ibwdt_driver);
375         if (err)
376                 return err;
377
378         ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
379                                                                 -1, NULL, 0);
380         if (IS_ERR(ibwdt_platform_device)) {
381                 err = PTR_ERR(ibwdt_platform_device);
382                 goto unreg_platform_driver;
383         }
384
385         return 0;
386
387 unreg_platform_driver:
388         platform_driver_unregister(&ibwdt_driver);
389         return err;
390 }
391
392 static void __exit ibwdt_exit(void)
393 {
394         platform_device_unregister(ibwdt_platform_device);
395         platform_driver_unregister(&ibwdt_driver);
396         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
397 }
398
399 module_init(ibwdt_init);
400 module_exit(ibwdt_exit);
401
402 MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
403 MODULE_DESCRIPTION("IB700 SBC watchdog driver");
404 MODULE_LICENSE("GPL");
405 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
406
407 /* end of ib700wdt.c */