1/*
  2 *	Acquire Single Board Computer Watchdog Timer driver
  3 *
  4 *	Based on wdt.c. Original copyright messages:
  5 *
  6 *	(c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  7 *						All Rights Reserved.
  8 *
  9 *	This program is free software; you can redistribute it and/or
 10 *	modify it under the terms of the GNU General Public License
 11 *	as published by the Free Software Foundation; either version
 12 *	2 of the License, or (at your option) any later version.
 13 *
 14 *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
 15 *	warranty for any of this software. This material is provided
 16 *	"AS-IS" and at no charge.
 17 *
 18 *	(c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
 19 *
 20 *	14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
 21 *	    Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
 22 *	    Can't add timeout - driver doesn't allow changing value
 23 */
 24
 25/*
 26 *	Theory of Operation:
 27 *		The Watch-Dog Timer is provided to ensure that standalone
 28 *		Systems can always recover from catastrophic conditions that
 29 *		caused the CPU to crash. This condition may have occurred by
 30 *		external EMI or a software bug. When the CPU stops working
 31 *		correctly, hardware on the board will either perform a hardware
 32 *		reset (cold boot) or a non-maskable interrupt (NMI) to bring the
 33 *		system back to a known state.
 34 *
 35 *		The Watch-Dog Timer is controlled by two I/O Ports.
 36 *		  443 hex	- Read	- Enable or refresh the Watch-Dog Timer
 37 *		  043 hex	- Read	- Disable the Watch-Dog Timer
 38 *
 39 *		To enable the Watch-Dog Timer, a read from I/O port 443h must
 40 *		be performed. This will enable and activate the countdown timer
 41 *		which will eventually time out and either reset the CPU or cause
 42 *		an NMI depending on the setting of a jumper. To ensure that this
 43 *		reset condition does not occur, the Watch-Dog Timer must be
 44 *		periodically refreshed by reading the same I/O port 443h.
 45 *		The Watch-Dog Timer is disabled by reading I/O port 043h.
 46 *
 47 *		The Watch-Dog Timer Time-Out Period is set via jumpers.
 48 *		It can be 1, 2, 10, 20, 110 or 220 seconds.
 49 */
 50
 51/*
 52 *	Includes, defines, variables, module parameters, ...
 53 */
 54
 
 
 55/* Includes */
 56#include <linux/module.h>		/* For module specific items */
 57#include <linux/moduleparam.h>		/* For new moduleparam's */
 58#include <linux/types.h>		/* For standard types (like size_t) */
 59#include <linux/errno.h>		/* For the -ENODEV/... values */
 60#include <linux/kernel.h>		/* For printk/panic/... */
 61#include <linux/miscdevice.h>		/* For MODULE_ALIAS_MISCDEV
 62							(WATCHDOG_MINOR) */
 63#include <linux/watchdog.h>		/* For the watchdog specific items */
 64#include <linux/fs.h>			/* For file operations */
 65#include <linux/ioport.h>		/* For io-port access */
 66#include <linux/platform_device.h>	/* For platform_driver framework */
 67#include <linux/init.h>			/* For __init/__exit/... */
 68#include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
 69#include <linux/io.h>			/* For inb/outb/... */
 70
 71/* Module information */
 72#define DRV_NAME "acquirewdt"
 73#define PFX DRV_NAME ": "
 74#define WATCHDOG_NAME "Acquire WDT"
 75/* There is no way to see what the correct time-out period is */
 76#define WATCHDOG_HEARTBEAT 0
 77
 78/* internal variables */
 79/* the watchdog platform device */
 80static struct platform_device *acq_platform_device;
 81static unsigned long acq_is_open;
 82static char expect_close;
 83
 84/* module parameters */
 85/* You must set this - there is no sane way to probe for this board. */
 86static int wdt_stop = 0x43;
 87module_param(wdt_stop, int, 0);
 88MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");
 89
 90/* You must set this - there is no sane way to probe for this board. */
 91static int wdt_start = 0x443;
 92module_param(wdt_start, int, 0);
 93MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");
 94
 95static int nowayout = WATCHDOG_NOWAYOUT;
 96module_param(nowayout, int, 0);
 97MODULE_PARM_DESC(nowayout,
 98	"Watchdog cannot be stopped once started (default="
 99	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
100
101/*
102 *	Watchdog Operations
103 */
104
105static void acq_keepalive(void)
106{
107	/* Write a watchdog value */
108	inb_p(wdt_start);
109}
110
111static void acq_stop(void)
112{
113	/* Turn the card off */
114	inb_p(wdt_stop);
115}
116
117/*
118 *	/dev/watchdog handling
119 */
120
121static ssize_t acq_write(struct file *file, const char __user *buf,
122						size_t count, loff_t *ppos)
123{
124	/* See if we got the magic character 'V' and reload the timer */
125	if (count) {
126		if (!nowayout) {
127			size_t i;
128			/* note: just in case someone wrote the magic character
129			   five months ago... */
130			expect_close = 0;
131			/* scan to see whether or not we got the
132			   magic character */
133			for (i = 0; i != count; i++) {
134				char c;
135				if (get_user(c, buf + i))
136					return -EFAULT;
137				if (c == 'V')
138					expect_close = 42;
139			}
140		}
141		/* Well, anyhow someone wrote to us, we should
142				return that favour */
143		acq_keepalive();
144	}
145	return count;
146}
147
148static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
149{
150	int options, retval = -EINVAL;
151	void __user *argp = (void __user *)arg;
152	int __user *p = argp;
153	static const struct watchdog_info ident = {
154		.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
155		.firmware_version = 1,
156		.identity = WATCHDOG_NAME,
157	};
158
159	switch (cmd) {
160	case WDIOC_GETSUPPORT:
161		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
162
163	case WDIOC_GETSTATUS:
164	case WDIOC_GETBOOTSTATUS:
165		return put_user(0, p);
166
167	case WDIOC_SETOPTIONS:
168	{
169		if (get_user(options, p))
170			return -EFAULT;
171		if (options & WDIOS_DISABLECARD) {
172			acq_stop();
173			retval = 0;
174		}
175		if (options & WDIOS_ENABLECARD) {
176			acq_keepalive();
177			retval = 0;
178		}
179		return retval;
180	}
181	case WDIOC_KEEPALIVE:
182		acq_keepalive();
183		return 0;
184
185	case WDIOC_GETTIMEOUT:
186		return put_user(WATCHDOG_HEARTBEAT, p);
187
188	default:
189		return -ENOTTY;
190	}
191}
192
193static int acq_open(struct inode *inode, struct file *file)
194{
195	if (test_and_set_bit(0, &acq_is_open))
196		return -EBUSY;
197
198	if (nowayout)
199		__module_get(THIS_MODULE);
200
201	/* Activate */
202	acq_keepalive();
203	return nonseekable_open(inode, file);
204}
205
206static int acq_close(struct inode *inode, struct file *file)
207{
208	if (expect_close == 42) {
209		acq_stop();
210	} else {
211		printk(KERN_CRIT PFX
212			"Unexpected close, not stopping watchdog!\n");
213		acq_keepalive();
214	}
215	clear_bit(0, &acq_is_open);
216	expect_close = 0;
217	return 0;
218}
219
220/*
221 *	Kernel Interfaces
222 */
223
224static const struct file_operations acq_fops = {
225	.owner		= THIS_MODULE,
226	.llseek		= no_llseek,
227	.write		= acq_write,
228	.unlocked_ioctl	= acq_ioctl,
229	.open		= acq_open,
230	.release	= acq_close,
231};
232
233static struct miscdevice acq_miscdev = {
234	.minor	= WATCHDOG_MINOR,
235	.name	= "watchdog",
236	.fops	= &acq_fops,
237};
238
239/*
240 *	Init & exit routines
241 */
242
243static int __devinit acq_probe(struct platform_device *dev)
244{
245	int ret;
246
247	if (wdt_stop != wdt_start) {
248		if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
249			printk(KERN_ERR PFX
250			    "I/O address 0x%04x already in use\n", 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 "I/O address 0x%04x already in use\n",
258			wdt_start);
259		ret = -EIO;
260		goto unreg_stop;
261	}
262	ret = misc_register(&acq_miscdev);
263	if (ret != 0) {
264		printk(KERN_ERR PFX
265			"cannot register miscdev on minor=%d (err=%d)\n",
266							WATCHDOG_MINOR, ret);
267		goto unreg_regions;
268	}
269	printk(KERN_INFO PFX "initialized. (nowayout=%d)\n", nowayout);
270
271	return 0;
272unreg_regions:
273	release_region(wdt_start, 1);
274unreg_stop:
275	if (wdt_stop != wdt_start)
276		release_region(wdt_stop, 1);
277out:
278	return ret;
279}
280
281static int __devexit acq_remove(struct platform_device *dev)
282{
283	misc_deregister(&acq_miscdev);
284	release_region(wdt_start, 1);
285	if (wdt_stop != wdt_start)
286		release_region(wdt_stop, 1);
287
288	return 0;
289}
290
291static void acq_shutdown(struct platform_device *dev)
292{
293	/* Turn the WDT off if we have a soft shutdown */
294	acq_stop();
295}
296
297static struct platform_driver acquirewdt_driver = {
298	.probe		= acq_probe,
299	.remove		= __devexit_p(acq_remove),
300	.shutdown	= acq_shutdown,
301	.driver		= {
302		.owner	= THIS_MODULE,
303		.name	= DRV_NAME,
304	},
305};
306
307static int __init acq_init(void)
308{
309	int err;
310
311	printk(KERN_INFO
312	      "WDT driver for Acquire single board computer initialising.\n");
313
314	err = platform_driver_register(&acquirewdt_driver);
315	if (err)
316		return err;
317
318	acq_platform_device = platform_device_register_simple(DRV_NAME,
319								-1, NULL, 0);
320	if (IS_ERR(acq_platform_device)) {
321		err = PTR_ERR(acq_platform_device);
322		goto unreg_platform_driver;
323	}
324	return 0;
325
326unreg_platform_driver:
327	platform_driver_unregister(&acquirewdt_driver);
328	return err;
329}
330
331static void __exit acq_exit(void)
332{
333	platform_device_unregister(acq_platform_device);
334	platform_driver_unregister(&acquirewdt_driver);
335	printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
336}
337
338module_init(acq_init);
339module_exit(acq_exit);
340
341MODULE_AUTHOR("David Woodhouse");
342MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
343MODULE_LICENSE("GPL");
344MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

  1/*
  2 *	Acquire Single Board Computer Watchdog Timer driver
  3 *
  4 *	Based on wdt.c. Original copyright messages:
  5 *
  6 *	(c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  7 *						All Rights Reserved.
  8 *
  9 *	This program is free software; you can redistribute it and/or
 10 *	modify it under the terms of the GNU General Public License
 11 *	as published by the Free Software Foundation; either version
 12 *	2 of the License, or (at your option) any later version.
 13 *
 14 *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
 15 *	warranty for any of this software. This material is provided
 16 *	"AS-IS" and at no charge.
 17 *
 18 *	(c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
 19 *
 20 *	14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
 21 *	    Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
 22 *	    Can't add timeout - driver doesn't allow changing value
 23 */
 24
 25/*
 26 *	Theory of Operation:
 27 *		The Watch-Dog Timer is provided to ensure that standalone
 28 *		Systems can always recover from catastrophic conditions that
 29 *		caused the CPU to crash. This condition may have occurred by
 30 *		external EMI or a software bug. When the CPU stops working
 31 *		correctly, hardware on the board will either perform a hardware
 32 *		reset (cold boot) or a non-maskable interrupt (NMI) to bring the
 33 *		system back to a known state.
 34 *
 35 *		The Watch-Dog Timer is controlled by two I/O Ports.
 36 *		  443 hex	- Read	- Enable or refresh the Watch-Dog Timer
 37 *		  043 hex	- Read	- Disable the Watch-Dog Timer
 38 *
 39 *		To enable the Watch-Dog Timer, a read from I/O port 443h must
 40 *		be performed. This will enable and activate the countdown timer
 41 *		which will eventually time out and either reset the CPU or cause
 42 *		an NMI depending on the setting of a jumper. To ensure that this
 43 *		reset condition does not occur, the Watch-Dog Timer must be
 44 *		periodically refreshed by reading the same I/O port 443h.
 45 *		The Watch-Dog Timer is disabled by reading I/O port 043h.
 46 *
 47 *		The Watch-Dog Timer Time-Out Period is set via jumpers.
 48 *		It can be 1, 2, 10, 20, 110 or 220 seconds.
 49 */
 50
 51/*
 52 *	Includes, defines, variables, module parameters, ...
 53 */
 54
 55#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 56
 57/* Includes */
 58#include <linux/module.h>		/* For module specific items */
 59#include <linux/moduleparam.h>		/* For new moduleparam's */
 60#include <linux/types.h>		/* For standard types (like size_t) */
 61#include <linux/errno.h>		/* For the -ENODEV/... values */
 62#include <linux/kernel.h>		/* For printk/panic/... */
 63#include <linux/miscdevice.h>		/* For MODULE_ALIAS_MISCDEV
 64							(WATCHDOG_MINOR) */
 65#include <linux/watchdog.h>		/* For the watchdog specific items */
 66#include <linux/fs.h>			/* For file operations */
 67#include <linux/ioport.h>		/* For io-port access */
 68#include <linux/platform_device.h>	/* For platform_driver framework */
 69#include <linux/init.h>			/* For __init/__exit/... */
 70#include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
 71#include <linux/io.h>			/* For inb/outb/... */
 72
 73/* Module information */
 74#define DRV_NAME "acquirewdt"
 
 75#define WATCHDOG_NAME "Acquire WDT"
 76/* There is no way to see what the correct time-out period is */
 77#define WATCHDOG_HEARTBEAT 0
 78
 79/* internal variables */
 80/* the watchdog platform device */
 81static struct platform_device *acq_platform_device;
 82static unsigned long acq_is_open;
 83static char expect_close;
 84
 85/* module parameters */
 86/* You must set this - there is no sane way to probe for this board. */
 87static int wdt_stop = 0x43;
 88module_param(wdt_stop, int, 0);
 89MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");
 90
 91/* You must set this - there is no sane way to probe for this board. */
 92static int wdt_start = 0x443;
 93module_param(wdt_start, int, 0);
 94MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");
 95
 96static bool nowayout = WATCHDOG_NOWAYOUT;
 97module_param(nowayout, bool, 0);
 98MODULE_PARM_DESC(nowayout,
 99	"Watchdog cannot be stopped once started (default="
100	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
101
102/*
103 *	Watchdog Operations
104 */
105
106static void acq_keepalive(void)
107{
108	/* Write a watchdog value */
109	inb_p(wdt_start);
110}
111
112static void acq_stop(void)
113{
114	/* Turn the card off */
115	inb_p(wdt_stop);
116}
117
118/*
119 *	/dev/watchdog handling
120 */
121
122static ssize_t acq_write(struct file *file, const char __user *buf,
123						size_t count, loff_t *ppos)
124{
125	/* See if we got the magic character 'V' and reload the timer */
126	if (count) {
127		if (!nowayout) {
128			size_t i;
129			/* note: just in case someone wrote the magic character
130			   five months ago... */
131			expect_close = 0;
132			/* scan to see whether or not we got the
133			   magic character */
134			for (i = 0; i != count; i++) {
135				char c;
136				if (get_user(c, buf + i))
137					return -EFAULT;
138				if (c == 'V')
139					expect_close = 42;
140			}
141		}
142		/* Well, anyhow someone wrote to us, we should
143				return that favour */
144		acq_keepalive();
145	}
146	return count;
147}
148
149static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
150{
151	int options, retval = -EINVAL;
152	void __user *argp = (void __user *)arg;
153	int __user *p = argp;
154	static const struct watchdog_info ident = {
155		.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
156		.firmware_version = 1,
157		.identity = WATCHDOG_NAME,
158	};
159
160	switch (cmd) {
161	case WDIOC_GETSUPPORT:
162		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
163
164	case WDIOC_GETSTATUS:
165	case WDIOC_GETBOOTSTATUS:
166		return put_user(0, p);
167
168	case WDIOC_SETOPTIONS:
169	{
170		if (get_user(options, p))
171			return -EFAULT;
172		if (options & WDIOS_DISABLECARD) {
173			acq_stop();
174			retval = 0;
175		}
176		if (options & WDIOS_ENABLECARD) {
177			acq_keepalive();
178			retval = 0;
179		}
180		return retval;
181	}
182	case WDIOC_KEEPALIVE:
183		acq_keepalive();
184		return 0;
185
186	case WDIOC_GETTIMEOUT:
187		return put_user(WATCHDOG_HEARTBEAT, p);
188
189	default:
190		return -ENOTTY;
191	}
192}
193
194static int acq_open(struct inode *inode, struct file *file)
195{
196	if (test_and_set_bit(0, &acq_is_open))
197		return -EBUSY;
198
199	if (nowayout)
200		__module_get(THIS_MODULE);
201
202	/* Activate */
203	acq_keepalive();
204	return nonseekable_open(inode, file);
205}
206
207static int acq_close(struct inode *inode, struct file *file)
208{
209	if (expect_close == 42) {
210		acq_stop();
211	} else {
212		pr_crit("Unexpected close, not stopping watchdog!\n");
 
213		acq_keepalive();
214	}
215	clear_bit(0, &acq_is_open);
216	expect_close = 0;
217	return 0;
218}
219
220/*
221 *	Kernel Interfaces
222 */
223
224static const struct file_operations acq_fops = {
225	.owner		= THIS_MODULE,
226	.llseek		= no_llseek,
227	.write		= acq_write,
228	.unlocked_ioctl	= acq_ioctl,
229	.open		= acq_open,
230	.release	= acq_close,
231};
232
233static struct miscdevice acq_miscdev = {
234	.minor	= WATCHDOG_MINOR,
235	.name	= "watchdog",
236	.fops	= &acq_fops,
237};
238
239/*
240 *	Init & exit routines
241 */
242
243static int __devinit acq_probe(struct platform_device *dev)
244{
245	int ret;
246
247	if (wdt_stop != wdt_start) {
248		if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
249			pr_err("I/O address 0x%04x already in use\n", wdt_stop);
 
250			ret = -EIO;
251			goto out;
252		}
253	}
254
255	if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
256		pr_err("I/O address 0x%04x already in use\n", wdt_start);
 
257		ret = -EIO;
258		goto unreg_stop;
259	}
260	ret = misc_register(&acq_miscdev);
261	if (ret != 0) {
262		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
263		       WATCHDOG_MINOR, ret);
 
264		goto unreg_regions;
265	}
266	pr_info("initialized. (nowayout=%d)\n", nowayout);
267
268	return 0;
269unreg_regions:
270	release_region(wdt_start, 1);
271unreg_stop:
272	if (wdt_stop != wdt_start)
273		release_region(wdt_stop, 1);
274out:
275	return ret;
276}
277
278static int __devexit acq_remove(struct platform_device *dev)
279{
280	misc_deregister(&acq_miscdev);
281	release_region(wdt_start, 1);
282	if (wdt_stop != wdt_start)
283		release_region(wdt_stop, 1);
284
285	return 0;
286}
287
288static void acq_shutdown(struct platform_device *dev)
289{
290	/* Turn the WDT off if we have a soft shutdown */
291	acq_stop();
292}
293
294static struct platform_driver acquirewdt_driver = {
295	.probe		= acq_probe,
296	.remove		= __devexit_p(acq_remove),
297	.shutdown	= acq_shutdown,
298	.driver		= {
299		.owner	= THIS_MODULE,
300		.name	= DRV_NAME,
301	},
302};
303
304static int __init acq_init(void)
305{
306	int err;
307
308	pr_info("WDT driver for Acquire single board computer initialising\n");
 
309
310	err = platform_driver_register(&acquirewdt_driver);
311	if (err)
312		return err;
313
314	acq_platform_device = platform_device_register_simple(DRV_NAME,
315								-1, NULL, 0);
316	if (IS_ERR(acq_platform_device)) {
317		err = PTR_ERR(acq_platform_device);
318		goto unreg_platform_driver;
319	}
320	return 0;
321
322unreg_platform_driver:
323	platform_driver_unregister(&acquirewdt_driver);
324	return err;
325}
326
327static void __exit acq_exit(void)
328{
329	platform_device_unregister(acq_platform_device);
330	platform_driver_unregister(&acquirewdt_driver);
331	pr_info("Watchdog Module Unloaded\n");
332}
333
334module_init(acq_init);
335module_exit(acq_exit);
336
337MODULE_AUTHOR("David Woodhouse");
338MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
339MODULE_LICENSE("GPL");
340MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);