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/notifier.h>
39 #include <linux/reboot.h>
40 #include <linux/init.h>
41
42 #include <asm/io.h>
43 #include <asm/uaccess.h>
44 #include <asm/system.h>
45
46 #define WATCHDOG_NAME "Advantech WDT"
47 #define PFX WATCHDOG_NAME ": "
48 #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
49
50 static unsigned long advwdt_is_open;
51 static char adv_expect_close;
52
53 /*
54 * You must set these - there is no sane way to probe for this board.
55 *
56 * To enable or restart, write the timeout value in seconds (1 to 63)
57 * to I/O port wdt_start. To disable, read I/O port wdt_stop.
58 * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
59 * check your manual (at least the PCA-6159 seems to be different -
60 * the manual says wdt_stop is 0x43, not 0x443).
61 * (0x43 is also a write-only control register for the 8254 timer!)
62 */
63
64 static int wdt_stop = 0x443;
65 module_param(wdt_stop, int, 0);
66 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
67
68 static int wdt_start = 0x443;
69 module_param(wdt_start, int, 0);
70 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
71
72 static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
73 module_param(timeout, int, 0);
74 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
75
76 #ifdef CONFIG_WATCHDOG_NOWAYOUT
77 static int nowayout = 1;
78 #else
79 static int nowayout = 0;
80 #endif
81
82 module_param(nowayout, int, 0);
83 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
84
85 /*
86 * Kernel methods.
87 */
88
89 static void
90 advwdt_ping(void)
91 {
92 /* Write a watchdog value */
93 outb_p(timeout, wdt_start);
94 }
95
96 static void
97 advwdt_disable(void)
98 {
99 inb_p(wdt_stop);
100 }
101
102 static ssize_t
103 advwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
104 {
105 if (count) {
106 if (!nowayout) {
107 size_t i;
108
109 adv_expect_close = 0;
110
111 for (i = 0; i != count; i++) {
112 char c;
113 if (get_user(c, buf+i))
114 return -EFAULT;
115 if (c == 'V')
116 adv_expect_close = 42;
117 }
118 }
119 advwdt_ping();
120 }
121 return count;
122 }
123
124 static int
125 advwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
126 unsigned long arg)
127 {
128 int new_timeout;
129 void __user *argp = (void __user *)arg;
130 int __user *p = argp;
131 static struct watchdog_info ident = {
132 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
133 .firmware_version = 1,
134 .identity = "Advantech WDT",
135 };
136
137 switch (cmd) {
138 case WDIOC_GETSUPPORT:
139 if (copy_to_user(argp, &ident, sizeof(ident)))
140 return -EFAULT;
141 break;
142
143 case WDIOC_GETSTATUS:
144 case WDIOC_GETBOOTSTATUS:
145 return put_user(0, p);
146
147 case WDIOC_KEEPALIVE:
148 advwdt_ping();
149 break;
150
151 case WDIOC_SETTIMEOUT:
152 if (get_user(new_timeout, p))
153 return -EFAULT;
154 if ((new_timeout < 1) || (new_timeout > 63))
155 return -EINVAL;
156 timeout = new_timeout;
157 advwdt_ping();
158 /* Fall */
159
160 case WDIOC_GETTIMEOUT:
161 return put_user(timeout, p);
162
163 case WDIOC_SETOPTIONS:
164 {
165 int options, retval = -EINVAL;
166
167 if (get_user(options, p))
168 return -EFAULT;
169
170 if (options & WDIOS_DISABLECARD) {
171 advwdt_disable();
172 retval = 0;
173 }
174
175 if (options & WDIOS_ENABLECARD) {
176 advwdt_ping();
177 retval = 0;
178 }
179
180 return retval;
181 }
182
183 default:
184 return -ENOIOCTLCMD;
185 }
186 return 0;
187 }
188
189 static int
190 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 "Unexpected close, not stopping watchdog!\n");
209 advwdt_ping();
210 }
211 clear_bit(0, &advwdt_is_open);
212 adv_expect_close = 0;
213 return 0;
214 }
215
216 /*
217 * Notifier for system down
218 */
219
220 static int
221 advwdt_notify_sys(struct notifier_block *this, unsigned long code,
222 void *unused)
223 {
224 if (code == SYS_DOWN || code == SYS_HALT) {
225 /* Turn the WDT off */
226 advwdt_disable();
227 }
228 return NOTIFY_DONE;
229 }
230
231 /*
232 * Kernel Interfaces
233 */
234
235 static struct file_operations advwdt_fops = {
236 .owner = THIS_MODULE,
237 .llseek = no_llseek,
238 .write = advwdt_write,
239 .ioctl = advwdt_ioctl,
240 .open = advwdt_open,
241 .release = advwdt_close,
242 };
243
244 static struct miscdevice advwdt_miscdev = {
245 .minor = WATCHDOG_MINOR,
246 .name = "watchdog",
247 .fops = &advwdt_fops,
248 };
249
250 /*
251 * The WDT needs to learn about soft shutdowns in order to
252 * turn the timebomb registers off.
253 */
254
255 static struct notifier_block advwdt_notifier = {
256 .notifier_call = advwdt_notify_sys,
257 };
258
259 static int __init
260 advwdt_init(void)
261 {
262 int ret;
263
264 printk(KERN_INFO "WDT driver for Advantech single board computer initialising.\n");
265
266 if (timeout < 1 || timeout > 63) {
267 timeout = WATCHDOG_TIMEOUT;
268 printk (KERN_INFO PFX "timeout value must be 1<=x<=63, using %d\n",
269 timeout);
270 }
271
272 if (wdt_stop != wdt_start) {
273 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
274 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
275 wdt_stop);
276 ret = -EIO;
277 goto out;
278 }
279 }
280
281 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
282 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
283 wdt_start);
284 ret = -EIO;
285 goto unreg_stop;
286 }
287
288 ret = register_reboot_notifier(&advwdt_notifier);
289 if (ret != 0) {
290 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
291 ret);
292 goto unreg_regions;
293 }
294
295 ret = misc_register(&advwdt_miscdev);
296 if (ret != 0) {
297 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
298 WATCHDOG_MINOR, ret);
299 goto unreg_reboot;
300 }
301
302 printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
303 timeout, nowayout);
304
305 out:
306 return ret;
307 unreg_reboot:
308 unregister_reboot_notifier(&advwdt_notifier);
309 unreg_regions:
310 release_region(wdt_start, 1);
311 unreg_stop:
312 if (wdt_stop != wdt_start)
313 release_region(wdt_stop, 1);
314 goto out;
315 }
316
317 static void __exit
318 advwdt_exit(void)
319 {
320 misc_deregister(&advwdt_miscdev);
321 unregister_reboot_notifier(&advwdt_notifier);
322 if(wdt_stop != wdt_start)
323 release_region(wdt_stop,1);
324 release_region(wdt_start,1);
325 }
326
327 module_init(advwdt_init);
328 module_exit(advwdt_exit);
329
330 MODULE_LICENSE("GPL");
331 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
332 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
333 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
334
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