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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
33 #include <linux/module.h>
34 #include <linux/moduleparam.h>
35 #include <linux/types.h>
36 #include <linux/miscdevice.h>
37 #include <linux/watchdog.h>
38 #include <linux/fs.h>
39 #include <linux/ioport.h>
40 #include <linux/platform_device.h>
41 #include <linux/init.h>
42 #include <linux/io.h>
43 #include <linux/uaccess.h>
44
45
46 #define DRV_NAME "advantechwdt"
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 bool nowayout = WATCHDOG_NOWAYOUT;
81 module_param(nowayout, bool, 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 through */
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 pr_crit("Unexpected close, not stopping watchdog!\n");
211 advwdt_ping();
212 }
213 clear_bit(0, &advwdt_is_open);
214 adv_expect_close = 0;
215 return 0;
216 }
217
218 /*
219 * Kernel Interfaces
220 */
221
222 static const struct file_operations advwdt_fops = {
223 .owner = THIS_MODULE,
224 .llseek = no_llseek,
225 .write = advwdt_write,
226 .unlocked_ioctl = advwdt_ioctl,
227 .open = advwdt_open,
228 .release = advwdt_close,
229 };
230
231 static struct miscdevice advwdt_miscdev = {
232 .minor = WATCHDOG_MINOR,
233 .name = "watchdog",
234 .fops = &advwdt_fops,
235 };
236
237 /*
238 * Init & exit routines
239 */
240
advwdt_probe(struct platform_device * dev)241 static int __init advwdt_probe(struct platform_device *dev)
242 {
243 int ret;
244
245 if (wdt_stop != wdt_start) {
246 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
247 pr_err("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 pr_err("I/O address 0x%04x already in use\n", wdt_start);
256 ret = -EIO;
257 goto unreg_stop;
258 }
259
260 /* Check that the heartbeat value is within it's range ;
261 * if not reset to the default */
262 if (advwdt_set_heartbeat(timeout)) {
263 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
264 pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
265 }
266
267 ret = misc_register(&advwdt_miscdev);
268 if (ret != 0) {
269 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
270 WATCHDOG_MINOR, ret);
271 goto unreg_regions;
272 }
273 pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
274 timeout, nowayout);
275 out:
276 return ret;
277 unreg_regions:
278 release_region(wdt_start, 1);
279 unreg_stop:
280 if (wdt_stop != wdt_start)
281 release_region(wdt_stop, 1);
282 goto out;
283 }
284
advwdt_remove(struct platform_device * dev)285 static int advwdt_remove(struct platform_device *dev)
286 {
287 misc_deregister(&advwdt_miscdev);
288 release_region(wdt_start, 1);
289 if (wdt_stop != wdt_start)
290 release_region(wdt_stop, 1);
291
292 return 0;
293 }
294
advwdt_shutdown(struct platform_device * dev)295 static void advwdt_shutdown(struct platform_device *dev)
296 {
297 /* Turn the WDT off if we have a soft shutdown */
298 advwdt_disable();
299 }
300
301 static struct platform_driver advwdt_driver = {
302 .remove = advwdt_remove,
303 .shutdown = advwdt_shutdown,
304 .driver = {
305 .name = DRV_NAME,
306 },
307 };
308
advwdt_init(void)309 static int __init advwdt_init(void)
310 {
311 int err;
312
313 pr_info("WDT driver for Advantech single board computer initialising\n");
314
315 advwdt_platform_device = platform_device_register_simple(DRV_NAME,
316 -1, NULL, 0);
317 if (IS_ERR(advwdt_platform_device))
318 return PTR_ERR(advwdt_platform_device);
319
320 err = platform_driver_probe(&advwdt_driver, advwdt_probe);
321 if (err)
322 goto unreg_platform_device;
323
324 return 0;
325
326 unreg_platform_device:
327 platform_device_unregister(advwdt_platform_device);
328 return err;
329 }
330
advwdt_exit(void)331 static void __exit advwdt_exit(void)
332 {
333 platform_device_unregister(advwdt_platform_device);
334 platform_driver_unregister(&advwdt_driver);
335 pr_info("Watchdog Module Unloaded\n");
336 }
337
338 module_init(advwdt_init);
339 module_exit(advwdt_exit);
340
341 MODULE_LICENSE("GPL");
342 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
343 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
344
