bfec16600475c906ed9a408c719598c0430ecb9b
[linux-2.6.git] / drivers / watchdog / advantechwdt.c
1 /*
2  *      Advantech Single Board Computer WDT driver
3  *
4  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
5  *
6  *      Based on acquirewdt.c which is based on wdt.c.
7  *      Original copyright messages:
8  *
9  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
10  *                              http://www.redhat.com
11  *
12  *      This program is free software; you can redistribute it and/or
13  *      modify it under the terms of the GNU General Public License
14  *      as published by the Free Software Foundation; either version
15  *      2 of the License, or (at your option) any later version.
16  *
17  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
18  *      warranty for any of this software. This material is provided
19  *      "AS-IS" and at no charge.
20  *
21  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
22  *
23  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
24  *          Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
25  *
26  *      16-Oct-2002 Rob Radez <rob@osinvestor.com>
27  *          Clean up ioctls, clean up init + exit, add expect close support,
28  *          add wdt_start and wdt_stop as parameters.
29  */
30
31 #include <linux/module.h>
32 #include <linux/moduleparam.h>
33 #include <linux/types.h>
34 #include <linux/miscdevice.h>
35 #include <linux/watchdog.h>
36 #include <linux/fs.h>
37 #include <linux/ioport.h>
38 #include <linux/platform_device.h>
39 #include <linux/init.h>
40 #include <linux/io.h>
41 #include <linux/uaccess.h>
42
43 #include <asm/system.h>
44
45 #define DRV_NAME "advantechwdt"
46 #define PFX DRV_NAME ": "
47 #define WATCHDOG_NAME "Advantech WDT"
48 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
49
50 static struct platform_device *advwdt_platform_device;  /* the watchdog platform device */
51 static unsigned long advwdt_is_open;
52 static char adv_expect_close;
53
54 /*
55  *      You must set these - there is no sane way to probe for this board.
56  *
57  *      To enable or restart, write the timeout value in seconds (1 to 63)
58  *      to I/O port wdt_start.  To disable, read I/O port wdt_stop.
59  *      Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
60  *      check your manual (at least the PCA-6159 seems to be different -
61  *      the manual says wdt_stop is 0x43, not 0x443).
62  *      (0x43 is also a write-only control register for the 8254 timer!)
63  */
64
65 static int wdt_stop = 0x443;
66 module_param(wdt_stop, int, 0);
67 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
68
69 static int wdt_start = 0x443;
70 module_param(wdt_start, int, 0);
71 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
72
73 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
74 module_param(timeout, int, 0);
75 MODULE_PARM_DESC(timeout,
76         "Watchdog timeout in seconds. 1<= timeout <=63, default="
77                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
78
79 static int nowayout = WATCHDOG_NOWAYOUT;
80 module_param(nowayout, int, 0);
81 MODULE_PARM_DESC(nowayout,
82         "Watchdog cannot be stopped once started (default="
83                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
84
85 /*
86  *      Watchdog Operations
87  */
88
89 static void advwdt_ping(void)
90 {
91         /* Write a watchdog value */
92         outb_p(timeout, wdt_start);
93 }
94
95 static void advwdt_disable(void)
96 {
97         inb_p(wdt_stop);
98 }
99
100 static int advwdt_set_heartbeat(int t)
101 {
102         if (t < 1 || t > 63)
103                 return -EINVAL;
104         timeout = t;
105         return 0;
106 }
107
108 /*
109  *      /dev/watchdog handling
110  */
111
112 static ssize_t advwdt_write(struct file *file, const char __user *buf,
113                                                 size_t count, loff_t *ppos)
114 {
115         if (count) {
116                 if (!nowayout) {
117                         size_t i;
118
119                         adv_expect_close = 0;
120
121                         for (i = 0; i != count; i++) {
122                                 char c;
123                                 if (get_user(c, buf+i))
124                                         return -EFAULT;
125                                 if (c == 'V')
126                                         adv_expect_close = 42;
127                         }
128                 }
129                 advwdt_ping();
130         }
131         return count;
132 }
133
134 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
135 {
136         int new_timeout;
137         void __user *argp = (void __user *)arg;
138         int __user *p = argp;
139         static struct watchdog_info ident = {
140                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
141                 .firmware_version = 1,
142                 .identity = WATCHDOG_NAME,
143         };
144
145         switch (cmd) {
146         case WDIOC_GETSUPPORT:
147                 if (copy_to_user(argp, &ident, sizeof(ident)))
148                         return -EFAULT;
149                 break;
150
151         case WDIOC_GETSTATUS:
152         case WDIOC_GETBOOTSTATUS:
153                 return put_user(0, p);
154
155         case WDIOC_SETOPTIONS:
156         {
157                 int options, retval = -EINVAL;
158
159                 if (get_user(options, p))
160                         return -EFAULT;
161                 if (options & WDIOS_DISABLECARD) {
162                         advwdt_disable();
163                         retval = 0;
164                 }
165                 if (options & WDIOS_ENABLECARD) {
166                         advwdt_ping();
167                         retval = 0;
168                 }
169                 return retval;
170         }
171         case WDIOC_KEEPALIVE:
172                 advwdt_ping();
173                 break;
174
175         case WDIOC_SETTIMEOUT:
176                 if (get_user(new_timeout, p))
177                         return -EFAULT;
178                 if (advwdt_set_heartbeat(new_timeout))
179                         return -EINVAL;
180                 advwdt_ping();
181                 /* Fall */
182         case WDIOC_GETTIMEOUT:
183                 return put_user(timeout, p);
184         default:
185                 return -ENOTTY;
186         }
187         return 0;
188 }
189
190 static int advwdt_open(struct inode *inode, struct file *file)
191 {
192         if (test_and_set_bit(0, &advwdt_is_open))
193                 return -EBUSY;
194         /*
195          *      Activate
196          */
197
198         advwdt_ping();
199         return nonseekable_open(inode, file);
200 }
201
202 static int
203 advwdt_close(struct inode *inode, struct file *file)
204 {
205         if (adv_expect_close == 42) {
206                 advwdt_disable();
207         } else {
208                 printk(KERN_CRIT PFX
209                                 "Unexpected close, not stopping watchdog!\n");
210                 advwdt_ping();
211         }
212         clear_bit(0, &advwdt_is_open);
213         adv_expect_close = 0;
214         return 0;
215 }
216
217 /*
218  *      Kernel Interfaces
219  */
220
221 static const struct file_operations advwdt_fops = {
222         .owner          = THIS_MODULE,
223         .llseek         = no_llseek,
224         .write          = advwdt_write,
225         .unlocked_ioctl = advwdt_ioctl,
226         .open           = advwdt_open,
227         .release        = advwdt_close,
228 };
229
230 static struct miscdevice advwdt_miscdev = {
231         .minor  = WATCHDOG_MINOR,
232         .name   = "watchdog",
233         .fops   = &advwdt_fops,
234 };
235
236 /*
237  *      Init & exit routines
238  */
239
240 static int __devinit advwdt_probe(struct platform_device *dev)
241 {
242         int ret;
243
244         if (wdt_stop != wdt_start) {
245                 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
246                         printk(KERN_ERR PFX
247                                 "I/O address 0x%04x already in use\n",
248                                                                 wdt_stop);
249                         ret = -EIO;
250                         goto out;
251                 }
252         }
253
254         if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
255                 printk(KERN_ERR PFX
256                                 "I/O address 0x%04x already in use\n",
257                                                                 wdt_start);
258                 ret = -EIO;
259                 goto unreg_stop;
260         }
261
262         /* Check that the heartbeat value is within it's range ; if not reset to the default */
263         if (advwdt_set_heartbeat(timeout)) {
264                 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
265                 printk(KERN_INFO PFX
266                         "timeout value must be 1<=x<=63, using %d\n", timeout);
267         }
268
269         ret = misc_register(&advwdt_miscdev);
270         if (ret != 0) {
271                 printk(KERN_ERR PFX
272                         "cannot register miscdev on minor=%d (err=%d)\n",
273                                                         WATCHDOG_MINOR, ret);
274                 goto unreg_regions;
275         }
276         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
277                 timeout, nowayout);
278 out:
279         return ret;
280 unreg_regions:
281         release_region(wdt_start, 1);
282 unreg_stop:
283         if (wdt_stop != wdt_start)
284                 release_region(wdt_stop, 1);
285         goto out;
286 }
287
288 static int __devexit advwdt_remove(struct platform_device *dev)
289 {
290         misc_deregister(&advwdt_miscdev);
291         release_region(wdt_start,1);
292         if(wdt_stop != wdt_start)
293                 release_region(wdt_stop,1);
294
295         return 0;
296 }
297
298 static void advwdt_shutdown(struct platform_device *dev)
299 {
300         /* Turn the WDT off if we have a soft shutdown */
301         advwdt_disable();
302 }
303
304 static struct platform_driver advwdt_driver = {
305         .probe          = advwdt_probe,
306         .remove         = __devexit_p(advwdt_remove),
307         .shutdown       = advwdt_shutdown,
308         .driver         = {
309                 .owner  = THIS_MODULE,
310                 .name   = DRV_NAME,
311         },
312 };
313
314 static int __init advwdt_init(void)
315 {
316         int err;
317
318         printk(KERN_INFO "WDT driver for Advantech single board computer initialising.\n");
319
320         err = platform_driver_register(&advwdt_driver);
321         if (err)
322                 return err;
323
324         advwdt_platform_device = platform_device_register_simple(DRV_NAME,
325                                                                 -1, NULL, 0);
326         if (IS_ERR(advwdt_platform_device)) {
327                 err = PTR_ERR(advwdt_platform_device);
328                 goto unreg_platform_driver;
329         }
330
331         return 0;
332
333 unreg_platform_driver:
334         platform_driver_unregister(&advwdt_driver);
335         return err;
336 }
337
338 static void __exit advwdt_exit(void)
339 {
340         platform_device_unregister(advwdt_platform_device);
341         platform_driver_unregister(&advwdt_driver);
342         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
343 }
344
345 module_init(advwdt_init);
346 module_exit(advwdt_exit);
347
348 MODULE_LICENSE("GPL");
349 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
350 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
351 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);