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