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 */
51static struct platform_device *advwdt_platform_device;
52static unsigned long advwdt_is_open;
53static 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
66static int wdt_stop = 0x443;
67module_param(wdt_stop, int, 0);
68MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
69
70static int wdt_start = 0x443;
71module_param(wdt_start, int, 0);
72MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
73
74static int timeout = WATCHDOG_TIMEOUT;	/* in seconds */
75module_param(timeout, int, 0);
76MODULE_PARM_DESC(timeout,
77	"Watchdog timeout in seconds. 1<= timeout <=63, default="
78		__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
79
80static bool nowayout = WATCHDOG_NOWAYOUT;
81module_param(nowayout, bool, 0);
82MODULE_PARM_DESC(nowayout,
83	"Watchdog cannot be stopped once started (default="
84		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
85
86/*
87 *	Watchdog Operations
88 */
89
90static void advwdt_ping(void)
91{
92	/* Write a watchdog value */
93	outb_p(timeout, wdt_start);
94}
95
96static void advwdt_disable(void)
97{
98	inb_p(wdt_stop);
99}
100
101static 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
113static 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
135static 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
193static 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
205static 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
222static 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
231static struct miscdevice advwdt_miscdev = {
232	.minor	= WATCHDOG_MINOR,
233	.name	= "watchdog",
234	.fops	= &advwdt_fops,
235};
236
237/*
238 *	Init & exit routines
239 */
240
241static 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);
275out:
276	return ret;
277unreg_regions:
278	release_region(wdt_start, 1);
279unreg_stop:
280	if (wdt_stop != wdt_start)
281		release_region(wdt_stop, 1);
282	goto out;
283}
284
285static 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
295static void advwdt_shutdown(struct platform_device *dev)
296{
297	/* Turn the WDT off if we have a soft shutdown */
298	advwdt_disable();
299}
300
301static struct platform_driver advwdt_driver = {
302	.remove		= advwdt_remove,
303	.shutdown	= advwdt_shutdown,
304	.driver		= {
305		.name	= DRV_NAME,
306	},
307};
308
309static 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
326unreg_platform_device:
327	platform_device_unregister(advwdt_platform_device);
328	return err;
329}
330
331static 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
338module_init(advwdt_init);
339module_exit(advwdt_exit);
340
341MODULE_LICENSE("GPL");
342MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
343MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
344