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
50static struct platform_device *advwdt_platform_device;	/* the watchdog platform device */
51static unsigned long advwdt_is_open;
52static 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
65static int wdt_stop = 0x443;
66module_param(wdt_stop, int, 0);
67MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
68
69static int wdt_start = 0x443;
70module_param(wdt_start, int, 0);
71MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
72
73static int timeout = WATCHDOG_TIMEOUT;	/* in seconds */
74module_param(timeout, int, 0);
75MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
76
77static int nowayout = WATCHDOG_NOWAYOUT;
78module_param(nowayout, int, 0);
79MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
80
81/*
82 *	Watchdog Operations
83 */
84
85static void
86advwdt_ping(void)
87{
88	/* Write a watchdog value */
89	outb_p(timeout, wdt_start);
90}
91
92static void
93advwdt_disable(void)
94{
95	inb_p(wdt_stop);
96}
97
98static int
99advwdt_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
112static ssize_t
113advwdt_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
134static int
135advwdt_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
198static int
199advwdt_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
211static int
212advwdt_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
229static 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
238static struct miscdevice advwdt_miscdev = {
239	.minor	= WATCHDOG_MINOR,
240	.name	= "watchdog",
241	.fops	= &advwdt_fops,
242};
243
244/*
245 *	Init & exit routines
246 */
247
248static int __devinit
249advwdt_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
286out:
287	return ret;
288unreg_regions:
289	release_region(wdt_start, 1);
290unreg_stop:
291	if (wdt_stop != wdt_start)
292		release_region(wdt_stop, 1);
293	goto out;
294}
295
296static int __devexit
297advwdt_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
307static void
308advwdt_shutdown(struct platform_device *dev)
309{
310	/* Turn the WDT off if we have a soft shutdown */
311	advwdt_disable();
312}
313
314static 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
324static int __init
325advwdt_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
343unreg_platform_driver:
344	platform_driver_unregister(&advwdt_driver);
345	return err;
346}
347
348static void __exit
349advwdt_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
356module_init(advwdt_init);
357module_exit(advwdt_exit);
358
359MODULE_LICENSE("GPL");
360MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
361MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
362MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
363