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 static int nowayout = WATCHDOG_NOWAYOUT;
77 module_param(nowayout, int, 0);
78 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
79
80 /*
81 * Kernel methods.
82 */
83
84 static void
85 advwdt_ping(void)
86 {
87 /* Write a watchdog value */
88 outb_p(timeout, wdt_start);
89 }
90
91 static void
92 advwdt_disable(void)
93 {
94 inb_p(wdt_stop);
95 }
96
97 static ssize_t
98 advwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
99 {
100 if (count) {
101 if (!nowayout) {
102 size_t i;
103
104 adv_expect_close = 0;
105
106 for (i = 0; i != count; i++) {
107 char c;
108 if (get_user(c, buf+i))
109 return -EFAULT;
110 if (c == 'V')
111 adv_expect_close = 42;
112 }
113 }
114 advwdt_ping();
115 }
116 return count;
117 }
118
119 static int
120 advwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
121 unsigned long arg)
122 {
123 int new_timeout;
124 void __user *argp = (void __user *)arg;
125 int __user *p = argp;
126 static struct watchdog_info ident = {
127 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
128 .firmware_version = 1,
129 .identity = "Advantech WDT",
130 };
131
132 switch (cmd) {
133 case WDIOC_GETSUPPORT:
134 if (copy_to_user(argp, &ident, sizeof(ident)))
135 return -EFAULT;
136 break;
137
138 case WDIOC_GETSTATUS:
139 case WDIOC_GETBOOTSTATUS:
140 return put_user(0, p);
141
142 case WDIOC_KEEPALIVE:
143 advwdt_ping();
144 break;
145
146 case WDIOC_SETTIMEOUT:
147 if (get_user(new_timeout, p))
148 return -EFAULT;
149 if ((new_timeout < 1) || (new_timeout > 63))
150 return -EINVAL;
151 timeout = new_timeout;
152 advwdt_ping();
153 /* Fall */
154
155 case WDIOC_GETTIMEOUT:
156 return put_user(timeout, p);
157
158 case WDIOC_SETOPTIONS:
159 {
160 int options, retval = -EINVAL;
161
162 if (get_user(options, p))
163 return -EFAULT;
164
165 if (options & WDIOS_DISABLECARD) {
166 advwdt_disable();
167 retval = 0;
168 }
169
170 if (options & WDIOS_ENABLECARD) {
171 advwdt_ping();
172 retval = 0;
173 }
174
175 return retval;
176 }
177
178 default:
179 return -ENOIOCTLCMD;
180 }
181 return 0;
182 }
183
184 static int
185 advwdt_open(struct inode *inode, struct file *file)
186 {
187 if (test_and_set_bit(0, &advwdt_is_open))
188 return -EBUSY;
189 /*
190 * Activate
191 */
192
193 advwdt_ping();
194 return nonseekable_open(inode, file);
195 }
196
197 static int
198 advwdt_close(struct inode *inode, struct file *file)
199 {
200 if (adv_expect_close == 42) {
201 advwdt_disable();
202 } else {
203 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
204 advwdt_ping();
205 }
206 clear_bit(0, &advwdt_is_open);
207 adv_expect_close = 0;
208 return 0;
209 }
210
211 /*
212 * Notifier for system down
213 */
214
215 static int
216 advwdt_notify_sys(struct notifier_block *this, unsigned long code,
217 void *unused)
218 {
219 if (code == SYS_DOWN || code == SYS_HALT) {
220 /* Turn the WDT off */
221 advwdt_disable();
222 }
223 return NOTIFY_DONE;
224 }
225
226 /*
227 * Kernel Interfaces
228 */
229
230 static struct file_operations advwdt_fops = {
231 .owner = THIS_MODULE,
232 .llseek = no_llseek,
233 .write = advwdt_write,
234 .ioctl = advwdt_ioctl,
235 .open = advwdt_open,
236 .release = advwdt_close,
237 };
238
239 static struct miscdevice advwdt_miscdev = {
240 .minor = WATCHDOG_MINOR,
241 .name = "watchdog",
242 .fops = &advwdt_fops,
243 };
244
245 /*
246 * The WDT needs to learn about soft shutdowns in order to
247 * turn the timebomb registers off.
248 */
249
250 static struct notifier_block advwdt_notifier = {
251 .notifier_call = advwdt_notify_sys,
252 };
253
254 static int __init
255 advwdt_init(void)
256 {
257 int ret;
258
259 printk(KERN_INFO "WDT driver for Advantech single board computer initialising.\n");
260
261 if (timeout < 1 || timeout > 63) {
262 timeout = WATCHDOG_TIMEOUT;
263 printk (KERN_INFO PFX "timeout value must be 1<=x<=63, using %d\n",
264 timeout);
265 }
266
267 if (wdt_stop != wdt_start) {
268 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
269 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
270 wdt_stop);
271 ret = -EIO;
272 goto out;
273 }
274 }
275
276 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
277 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
278 wdt_start);
279 ret = -EIO;
280 goto unreg_stop;
281 }
282
283 ret = register_reboot_notifier(&advwdt_notifier);
284 if (ret != 0) {
285 printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
286 ret);
287 goto unreg_regions;
288 }
289
290 ret = misc_register(&advwdt_miscdev);
291 if (ret != 0) {
292 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
293 WATCHDOG_MINOR, ret);
294 goto unreg_reboot;
295 }
296
297 printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
298 timeout, nowayout);
299
300 out:
301 return ret;
302 unreg_reboot:
303 unregister_reboot_notifier(&advwdt_notifier);
304 unreg_regions:
305 release_region(wdt_start, 1);
306 unreg_stop:
307 if (wdt_stop != wdt_start)
308 release_region(wdt_stop, 1);
309 goto out;
310 }
311
312 static void __exit
313 advwdt_exit(void)
314 {
315 misc_deregister(&advwdt_miscdev);
316 unregister_reboot_notifier(&advwdt_notifier);
317 if(wdt_stop != wdt_start)
318 release_region(wdt_stop,1);
319 release_region(wdt_start,1);
320 }
321
322 module_init(advwdt_init);
323 module_exit(advwdt_exit);
324
325 MODULE_LICENSE("GPL");
326 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
327 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
328 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
329
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