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
41 #include <asm/io.h>
42 #include <asm/uaccess.h>
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, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
76
77 static int nowayout = WATCHDOG_NOWAYOUT;
78 module_param(nowayout, int, 0);
79 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
80
81 /*
82 * Watchdog Operations
83 */
84
85 static void
86 advwdt_ping(void)
87 {
88 /* Write a watchdog value */
89 outb_p(timeout, wdt_start);
90 }
91
92 static void
93 advwdt_disable(void)
94 {
95 inb_p(wdt_stop);
96 }
97
98 static int
99 advwdt_set_heartbeat(int t)
100 {
101 if ((t < 1) || (t > 63))
102 return -EINVAL;
103
104 timeout = t;
105 return 0;
106 }
107
108 /*
109 * /dev/watchdog handling
110 */
111
112 static ssize_t
113 advwdt_write(struct file *file, const char __user *buf, 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 int
135 advwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
136 unsigned long arg)
137 {
138 int new_timeout;
139 void __user *argp = (void __user *)arg;
140 int __user *p = argp;
141 static struct watchdog_info ident = {
142 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
143 .firmware_version = 1,
144 .identity = WATCHDOG_NAME,
145 };
146
147 switch (cmd) {
148 case WDIOC_GETSUPPORT:
149 if (copy_to_user(argp, &ident, sizeof(ident)))
150 return -EFAULT;
151 break;
152
153 case WDIOC_GETSTATUS:
154 case WDIOC_GETBOOTSTATUS:
155 return put_user(0, p);
156
157 case WDIOC_KEEPALIVE:
158 advwdt_ping();
159 break;
160
161 case WDIOC_SETTIMEOUT:
162 if (get_user(new_timeout, p))
163 return -EFAULT;
164 if (advwdt_set_heartbeat(new_timeout))
165 return -EINVAL;
166 advwdt_ping();
167 /* Fall */
168
169 case WDIOC_GETTIMEOUT:
170 return put_user(timeout, p);
171
172 case WDIOC_SETOPTIONS:
173 {
174 int options, retval = -EINVAL;
175
176 if (get_user(options, p))
177 return -EFAULT;
178
179 if (options & WDIOS_DISABLECARD) {
180 advwdt_disable();
181 retval = 0;
182 }
183
184 if (options & WDIOS_ENABLECARD) {
185 advwdt_ping();
186 retval = 0;
187 }
188
189 return retval;
190 }
191
192 default:
193 return -ENOTTY;
194 }
195 return 0;
196 }
197
198 static int
199 advwdt_open(struct inode *inode, struct file *file)
200 {
201 if (test_and_set_bit(0, &advwdt_is_open))
202 return -EBUSY;
203 /*
204 * Activate
205 */
206
207 advwdt_ping();
208 return nonseekable_open(inode, file);
209 }
210
211 static int
212 advwdt_close(struct inode *inode, struct file *file)
213 {
214 if (adv_expect_close == 42) {
215 advwdt_disable();
216 } else {
217 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
218 advwdt_ping();
219 }
220 clear_bit(0, &advwdt_is_open);
221 adv_expect_close = 0;
222 return 0;
223 }
224
225 /*
226 * Kernel Interfaces
227 */
228
229 static const struct file_operations advwdt_fops = {
230 .owner = THIS_MODULE,
231 .llseek = no_llseek,
232 .write = advwdt_write,
233 .ioctl = advwdt_ioctl,
234 .open = advwdt_open,
235 .release = advwdt_close,
236 };
237
238 static struct miscdevice advwdt_miscdev = {
239 .minor = WATCHDOG_MINOR,
240 .name = "watchdog",
241 .fops = &advwdt_fops,
242 };
243
244 /*
245 * Init & exit routines
246 */
247
248 static int __devinit
249 advwdt_probe(struct platform_device *dev)
250 {
251 int ret;
252
253 if (wdt_stop != wdt_start) {
254 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
255 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
256 wdt_stop);
257 ret = -EIO;
258 goto out;
259 }
260 }
261
262 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
263 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
264 wdt_start);
265 ret = -EIO;
266 goto unreg_stop;
267 }
268
269 /* Check that the heartbeat value is within it's range ; if not reset to the default */
270 if (advwdt_set_heartbeat(timeout)) {
271 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
272 printk (KERN_INFO PFX "timeout value must be 1<=x<=63, using %d\n",
273 timeout);
274 }
275
276 ret = misc_register(&advwdt_miscdev);
277 if (ret != 0) {
278 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
279 WATCHDOG_MINOR, ret);
280 goto unreg_regions;
281 }
282
283 printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
284 timeout, nowayout);
285
286 out:
287 return ret;
288 unreg_regions:
289 release_region(wdt_start, 1);
290 unreg_stop:
291 if (wdt_stop != wdt_start)
292 release_region(wdt_stop, 1);
293 goto out;
294 }
295
296 static int __devexit
297 advwdt_remove(struct platform_device *dev)
298 {
299 misc_deregister(&advwdt_miscdev);
300 release_region(wdt_start,1);
301 if(wdt_stop != wdt_start)
302 release_region(wdt_stop,1);
303
304 return 0;
305 }
306
307 static void
308 advwdt_shutdown(struct platform_device *dev)
309 {
310 /* Turn the WDT off if we have a soft shutdown */
311 advwdt_disable();
312 }
313
314 static struct platform_driver advwdt_driver = {
315 .probe = advwdt_probe,
316 .remove = __devexit_p(advwdt_remove),
317 .shutdown = advwdt_shutdown,
318 .driver = {
319 .owner = THIS_MODULE,
320 .name = DRV_NAME,
321 },
322 };
323
324 static int __init
325 advwdt_init(void)
326 {
327 int err;
328
329 printk(KERN_INFO "WDT driver for Advantech single board computer initialising.\n");
330
331 err = platform_driver_register(&advwdt_driver);
332 if (err)
333 return err;
334
335 advwdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
336 if (IS_ERR(advwdt_platform_device)) {
337 err = PTR_ERR(advwdt_platform_device);
338 goto unreg_platform_driver;
339 }
340
341 return 0;
342
343 unreg_platform_driver:
344 platform_driver_unregister(&advwdt_driver);
345 return err;
346 }
347
348 static void __exit
349 advwdt_exit(void)
350 {
351 platform_device_unregister(advwdt_platform_device);
352 platform_driver_unregister(&advwdt_driver);
353 printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
354 }
355
356 module_init(advwdt_init);
357 module_exit(advwdt_exit);
358
359 MODULE_LICENSE("GPL");
360 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
361 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
362 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
363
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