xref: /openbmc/linux/drivers/watchdog/advantechwdt.c (revision baa7eb025ab14f3cba2e35c0a8648f9c9f01d24f) 
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 
90 static void advwdt_ping(void)
91 {
92 	/* Write a watchdog value */
93 	outb_p(timeout, wdt_start);
94 }
95 
96 static void advwdt_disable(void)
97 {
98 	inb_p(wdt_stop);
99 }
100 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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