Merge tag 'dm-3.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm
[linux-3.10.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@lxorguk.ukuu.org.uk>,
15  *                                              All Rights Reserved.
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@lxorguk.ukuu.org.uk>
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 #define WDT_STOP 0x441
95 #define WDT_START 0x443
96
97 /* Default timeout */
98 #define WATCHDOG_TIMEOUT 30             /* 30 seconds +/- 20% */
99 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
100 module_param(timeout, int, 0);
101 MODULE_PARM_DESC(timeout,
102         "Watchdog timeout in seconds. 0<= timeout <=30, default="
103                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
104
105 static int nowayout = WATCHDOG_NOWAYOUT;
106 module_param(nowayout, int, 0);
107 MODULE_PARM_DESC(nowayout,
108                 "Watchdog cannot be stopped once started (default="
109                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
110
111
112 /*
113  *      Watchdog Operations
114  */
115
116 static void ibwdt_ping(void)
117 {
118         int wd_margin = 15 - ((timeout + 1) / 2);
119
120         spin_lock(&ibwdt_lock);
121
122         /* Write a watchdog value */
123         outb_p(wd_margin, WDT_START);
124
125         spin_unlock(&ibwdt_lock);
126 }
127
128 static void ibwdt_disable(void)
129 {
130         spin_lock(&ibwdt_lock);
131         outb_p(0, WDT_STOP);
132         spin_unlock(&ibwdt_lock);
133 }
134
135 static int ibwdt_set_heartbeat(int t)
136 {
137         if (t < 0 || t > 30)
138                 return -EINVAL;
139
140         timeout = t;
141         return 0;
142 }
143
144 /*
145  *      /dev/watchdog handling
146  */
147
148 static ssize_t ibwdt_write(struct file *file, const char __user *buf,
149                                                 size_t count, loff_t *ppos)
150 {
151         if (count) {
152                 if (!nowayout) {
153                         size_t i;
154
155                         /* In case it was set long ago */
156                         expect_close = 0;
157
158                         for (i = 0; i != count; i++) {
159                                 char c;
160                                 if (get_user(c, buf + i))
161                                         return -EFAULT;
162                                 if (c == 'V')
163                                         expect_close = 42;
164                         }
165                 }
166                 ibwdt_ping();
167         }
168         return count;
169 }
170
171 static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
172 {
173         int new_margin;
174         void __user *argp = (void __user *)arg;
175         int __user *p = argp;
176
177         static const struct watchdog_info ident = {
178                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
179                                                         | WDIOF_MAGICCLOSE,
180                 .firmware_version = 1,
181                 .identity = "IB700 WDT",
182         };
183
184         switch (cmd) {
185         case WDIOC_GETSUPPORT:
186                 if (copy_to_user(argp, &ident, sizeof(ident)))
187                         return -EFAULT;
188                 break;
189
190         case WDIOC_GETSTATUS:
191         case WDIOC_GETBOOTSTATUS:
192                 return put_user(0, p);
193
194         case WDIOC_SETOPTIONS:
195         {
196                 int options, retval = -EINVAL;
197
198                 if (get_user(options, p))
199                         return -EFAULT;
200
201                 if (options & WDIOS_DISABLECARD) {
202                         ibwdt_disable();
203                         retval = 0;
204                 }
205                 if (options & WDIOS_ENABLECARD) {
206                         ibwdt_ping();
207                         retval = 0;
208                 }
209                 return retval;
210         }
211         case WDIOC_KEEPALIVE:
212                 ibwdt_ping();
213                 break;
214
215         case WDIOC_SETTIMEOUT:
216                 if (get_user(new_margin, p))
217                         return -EFAULT;
218                 if (ibwdt_set_heartbeat(new_margin))
219                         return -EINVAL;
220                 ibwdt_ping();
221                 /* Fall */
222
223         case WDIOC_GETTIMEOUT:
224                 return put_user(timeout, p);
225
226         default:
227                 return -ENOTTY;
228         }
229         return 0;
230 }
231
232 static int ibwdt_open(struct inode *inode, struct file *file)
233 {
234         if (test_and_set_bit(0, &ibwdt_is_open))
235                 return -EBUSY;
236         if (nowayout)
237                 __module_get(THIS_MODULE);
238
239         /* Activate */
240         ibwdt_ping();
241         return nonseekable_open(inode, file);
242 }
243
244 static int ibwdt_close(struct inode *inode, struct file *file)
245 {
246         if (expect_close == 42) {
247                 ibwdt_disable();
248         } else {
249                 printk(KERN_CRIT PFX
250                      "WDT device closed unexpectedly.  WDT will not stop!\n");
251                 ibwdt_ping();
252         }
253         clear_bit(0, &ibwdt_is_open);
254         expect_close = 0;
255         return 0;
256 }
257
258 /*
259  *      Kernel Interfaces
260  */
261
262 static const struct file_operations ibwdt_fops = {
263         .owner          = THIS_MODULE,
264         .llseek         = no_llseek,
265         .write          = ibwdt_write,
266         .unlocked_ioctl = ibwdt_ioctl,
267         .open           = ibwdt_open,
268         .release        = ibwdt_close,
269 };
270
271 static struct miscdevice ibwdt_miscdev = {
272         .minor = WATCHDOG_MINOR,
273         .name = "watchdog",
274         .fops = &ibwdt_fops,
275 };
276
277 /*
278  *      Init & exit routines
279  */
280
281 static int __devinit ibwdt_probe(struct platform_device *dev)
282 {
283         int res;
284
285 #if WDT_START != WDT_STOP
286         if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
287                 printk(KERN_ERR PFX "STOP method I/O %X is not available.\n",
288                                                                 WDT_STOP);
289                 res = -EIO;
290                 goto out_nostopreg;
291         }
292 #endif
293
294         if (!request_region(WDT_START, 1, "IB700 WDT")) {
295                 printk(KERN_ERR PFX "START method I/O %X is not available.\n",
296                                                                 WDT_START);
297                 res = -EIO;
298                 goto out_nostartreg;
299         }
300
301         /* Check that the heartbeat value is within it's range ;
302          * if not reset to the default */
303         if (ibwdt_set_heartbeat(timeout)) {
304                 ibwdt_set_heartbeat(WATCHDOG_TIMEOUT);
305                 printk(KERN_INFO PFX
306                         "timeout value must be 0<=x<=30, using %d\n", timeout);
307         }
308
309         res = misc_register(&ibwdt_miscdev);
310         if (res) {
311                 printk(KERN_ERR PFX "failed to register misc device\n");
312                 goto out_nomisc;
313         }
314         return 0;
315
316 out_nomisc:
317         release_region(WDT_START, 1);
318 out_nostartreg:
319 #if WDT_START != WDT_STOP
320         release_region(WDT_STOP, 1);
321 #endif
322 out_nostopreg:
323         return res;
324 }
325
326 static int __devexit ibwdt_remove(struct platform_device *dev)
327 {
328         misc_deregister(&ibwdt_miscdev);
329         release_region(WDT_START, 1);
330 #if WDT_START != WDT_STOP
331         release_region(WDT_STOP, 1);
332 #endif
333         return 0;
334 }
335
336 static void ibwdt_shutdown(struct platform_device *dev)
337 {
338         /* Turn the WDT off if we have a soft shutdown */
339         ibwdt_disable();
340 }
341
342 static struct platform_driver ibwdt_driver = {
343         .probe          = ibwdt_probe,
344         .remove         = __devexit_p(ibwdt_remove),
345         .shutdown       = ibwdt_shutdown,
346         .driver         = {
347                 .owner  = THIS_MODULE,
348                 .name   = DRV_NAME,
349         },
350 };
351
352 static int __init ibwdt_init(void)
353 {
354         int err;
355
356         printk(KERN_INFO PFX
357                 "WDT driver for IB700 single board computer initialising.\n");
358
359         err = platform_driver_register(&ibwdt_driver);
360         if (err)
361                 return err;
362
363         ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
364                                                                 -1, NULL, 0);
365         if (IS_ERR(ibwdt_platform_device)) {
366                 err = PTR_ERR(ibwdt_platform_device);
367                 goto unreg_platform_driver;
368         }
369
370         return 0;
371
372 unreg_platform_driver:
373         platform_driver_unregister(&ibwdt_driver);
374         return err;
375 }
376
377 static void __exit ibwdt_exit(void)
378 {
379         platform_device_unregister(ibwdt_platform_device);
380         platform_driver_unregister(&ibwdt_driver);
381         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
382 }
383
384 module_init(ibwdt_init);
385 module_exit(ibwdt_exit);
386
387 MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
388 MODULE_DESCRIPTION("IB700 SBC watchdog driver");
389 MODULE_LICENSE("GPL");
390 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
391
392 /* end of ib700wdt.c */