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@lxorguk.ukuu.org.uk>,
10 * All Rights Reserved.
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@lxorguk.ukuu.org.uk>
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 /* the watchdog platform device */
51 static struct platform_device *advwdt_platform_device;
52 static unsigned long advwdt_is_open;
53 static char adv_expect_close;
54
55 /*
56 * You must set these - there is no sane way to probe for this board.
57 *
58 * To enable or restart, write the timeout value in seconds (1 to 63)
59 * to I/O port wdt_start. To disable, read I/O port wdt_stop.
60 * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
61 * check your manual (at least the PCA-6159 seems to be different -
62 * the manual says wdt_stop is 0x43, not 0x443).
63 * (0x43 is also a write-only control register for the 8254 timer!)
64 */
65
66 static int wdt_stop = 0x443;
67 module_param(wdt_stop, int, 0);
68 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
69
70 static int wdt_start = 0x443;
71 module_param(wdt_start, int, 0);
72 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
73
74 static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
75 module_param(timeout, int, 0);
76 MODULE_PARM_DESC(timeout,
77 "Watchdog timeout in seconds. 1<= timeout <=63, default="
78 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
79
80 static int nowayout = WATCHDOG_NOWAYOUT;
81 module_param(nowayout, int, 0);
82 MODULE_PARM_DESC(nowayout,
83 "Watchdog cannot be stopped once started (default="
84 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
85
86 /*
87 * Watchdog Operations
88 */
89
advwdt_ping(void)90 static void advwdt_ping(void)
91 {
92 /* Write a watchdog value */
93 outb_p(timeout, wdt_start);
94 }
95
advwdt_disable(void)96 static void advwdt_disable(void)
97 {
98 inb_p(wdt_stop);
99 }
100
advwdt_set_heartbeat(int t)101 static int advwdt_set_heartbeat(int t)
102 {
103 if (t < 1 || t > 63)
104 return -EINVAL;
105 timeout = t;
106 return 0;
107 }
108
109 /*
110 * /dev/watchdog handling
111 */
112
advwdt_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)113 static ssize_t advwdt_write(struct file *file, const char __user *buf,
114 size_t count, loff_t *ppos)
115 {
116 if (count) {
117 if (!nowayout) {
118 size_t i;
119
120 adv_expect_close = 0;
121
122 for (i = 0; i != count; i++) {
123 char c;
124 if (get_user(c, buf + i))
125 return -EFAULT;
126 if (c == 'V')
127 adv_expect_close = 42;
128 }
129 }
130 advwdt_ping();
131 }
132 return count;
133 }
134
advwdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)135 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
136 {
137 int new_timeout;
138 void __user *argp = (void __user *)arg;
139 int __user *p = argp;
140 static const struct watchdog_info ident = {
141 .options = WDIOF_KEEPALIVEPING |
142 WDIOF_SETTIMEOUT |
143 WDIOF_MAGICCLOSE,
144 .firmware_version = 1,
145 .identity = WATCHDOG_NAME,
146 };
147
148 switch (cmd) {
149 case WDIOC_GETSUPPORT:
150 if (copy_to_user(argp, &ident, sizeof(ident)))
151 return -EFAULT;
152 break;
153
154 case WDIOC_GETSTATUS:
155 case WDIOC_GETBOOTSTATUS:
156 return put_user(0, p);
157
158 case WDIOC_SETOPTIONS:
159 {
160 int options, retval = -EINVAL;
161
162 if (get_user(options, p))
163 return -EFAULT;
164 if (options & WDIOS_DISABLECARD) {
165 advwdt_disable();
166 retval = 0;
167 }
168 if (options & WDIOS_ENABLECARD) {
169 advwdt_ping();
170 retval = 0;
171 }
172 return retval;
173 }
174 case WDIOC_KEEPALIVE:
175 advwdt_ping();
176 break;
177
178 case WDIOC_SETTIMEOUT:
179 if (get_user(new_timeout, p))
180 return -EFAULT;
181 if (advwdt_set_heartbeat(new_timeout))
182 return -EINVAL;
183 advwdt_ping();
184 /* Fall */
185 case WDIOC_GETTIMEOUT:
186 return put_user(timeout, p);
187 default:
188 return -ENOTTY;
189 }
190 return 0;
191 }
192
advwdt_open(struct inode * inode,struct file * file)193 static int advwdt_open(struct inode *inode, struct file *file)
194 {
195 if (test_and_set_bit(0, &advwdt_is_open))
196 return -EBUSY;
197 /*
198 * Activate
199 */
200
201 advwdt_ping();
202 return nonseekable_open(inode, file);
203 }
204
advwdt_close(struct inode * inode,struct file * file)205 static int advwdt_close(struct inode *inode, struct file *file)
206 {
207 if (adv_expect_close == 42) {
208 advwdt_disable();
209 } else {
210 printk(KERN_CRIT PFX
211 "Unexpected close, not stopping watchdog!\n");
212 advwdt_ping();
213 }
214 clear_bit(0, &advwdt_is_open);
215 adv_expect_close = 0;
216 return 0;
217 }
218
219 /*
220 * Kernel Interfaces
221 */
222
223 static const struct file_operations advwdt_fops = {
224 .owner = THIS_MODULE,
225 .llseek = no_llseek,
226 .write = advwdt_write,
227 .unlocked_ioctl = advwdt_ioctl,
228 .open = advwdt_open,
229 .release = advwdt_close,
230 };
231
232 static struct miscdevice advwdt_miscdev = {
233 .minor = WATCHDOG_MINOR,
234 .name = "watchdog",
235 .fops = &advwdt_fops,
236 };
237
238 /*
239 * Init & exit routines
240 */
241
advwdt_probe(struct platform_device * dev)242 static int __devinit advwdt_probe(struct platform_device *dev)
243 {
244 int ret;
245
246 if (wdt_stop != wdt_start) {
247 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
248 printk(KERN_ERR PFX
249 "I/O address 0x%04x already in use\n",
250 wdt_stop);
251 ret = -EIO;
252 goto out;
253 }
254 }
255
256 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
257 printk(KERN_ERR PFX
258 "I/O address 0x%04x already in use\n",
259 wdt_start);
260 ret = -EIO;
261 goto unreg_stop;
262 }
263
264 /* Check that the heartbeat value is within it's range ;
265 * if not reset to the default */
266 if (advwdt_set_heartbeat(timeout)) {
267 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
268 printk(KERN_INFO PFX
269 "timeout value must be 1<=x<=63, using %d\n", timeout);
270 }
271
272 ret = misc_register(&advwdt_miscdev);
273 if (ret != 0) {
274 printk(KERN_ERR PFX
275 "cannot register miscdev on minor=%d (err=%d)\n",
276 WATCHDOG_MINOR, ret);
277 goto unreg_regions;
278 }
279 printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
280 timeout, nowayout);
281 out:
282 return ret;
283 unreg_regions:
284 release_region(wdt_start, 1);
285 unreg_stop:
286 if (wdt_stop != wdt_start)
287 release_region(wdt_stop, 1);
288 goto out;
289 }
290
advwdt_remove(struct platform_device * dev)291 static int __devexit advwdt_remove(struct platform_device *dev)
292 {
293 misc_deregister(&advwdt_miscdev);
294 release_region(wdt_start, 1);
295 if (wdt_stop != wdt_start)
296 release_region(wdt_stop, 1);
297
298 return 0;
299 }
300
advwdt_shutdown(struct platform_device * dev)301 static void advwdt_shutdown(struct platform_device *dev)
302 {
303 /* Turn the WDT off if we have a soft shutdown */
304 advwdt_disable();
305 }
306
307 static struct platform_driver advwdt_driver = {
308 .probe = advwdt_probe,
309 .remove = __devexit_p(advwdt_remove),
310 .shutdown = advwdt_shutdown,
311 .driver = {
312 .owner = THIS_MODULE,
313 .name = DRV_NAME,
314 },
315 };
316
advwdt_init(void)317 static int __init advwdt_init(void)
318 {
319 int err;
320
321 printk(KERN_INFO
322 "WDT driver for Advantech single board computer initialising.\n");
323
324 err = platform_driver_register(&advwdt_driver);
325 if (err)
326 return err;
327
328 advwdt_platform_device = platform_device_register_simple(DRV_NAME,
329 -1, NULL, 0);
330 if (IS_ERR(advwdt_platform_device)) {
331 err = PTR_ERR(advwdt_platform_device);
332 goto unreg_platform_driver;
333 }
334
335 return 0;
336
337 unreg_platform_driver:
338 platform_driver_unregister(&advwdt_driver);
339 return err;
340 }
341
advwdt_exit(void)342 static void __exit advwdt_exit(void)
343 {
344 platform_device_unregister(advwdt_platform_device);
345 platform_driver_unregister(&advwdt_driver);
346 printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
347 }
348
349 module_init(advwdt_init);
350 module_exit(advwdt_exit);
351
352 MODULE_LICENSE("GPL");
353 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
354 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
355 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
356