[linux-2.6-block.git] / drivers / watchdog / acquirewdt.c

/*
 *	Acquire Single Board Computer Watchdog Timer driver
 *
 *      Based on wdt.c. Original copyright messages:
 *
 *	(c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
 *				http://www.redhat.com
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
 *	warranty for any of this software. This material is provided
 *	"AS-IS" and at no charge.
 *
 *	(c) Copyright 1995    Alan Cox <alan@redhat.com>
 *
 *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
 *          Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
 *          Can't add timeout - driver doesn't allow changing value
 */

/*
 *	Theory of Operation:
 *		The Watch-Dog Timer is provided to ensure that standalone
 *		Systems can always recover from catastrophic conditions that
 *		caused the CPU to crash. This condition may have occured by
 *		external EMI or a software bug. When the CPU stops working
 *		correctly, hardware on the board will either perform a hardware
 *		reset (cold boot) or a non-maskable interrupt (NMI) to bring the
 *		system back to a known state.
 *
 *		The Watch-Dog Timer is controlled by two I/O Ports.
 *		  443 hex	- Read	- Enable or refresh the Watch-Dog Timer
 *		  043 hex	- Read	- Disable the Watch-Dog Timer
 *
 *		To enable the Watch-Dog Timer, a read from I/O port 443h must
 *		be performed. This will enable and activate the countdown timer
 *		which will eventually time out and either reset the CPU or cause
 *		an NMI depending on the setting of a jumper. To ensure that this
 *		reset condition does not occur, the Watch-Dog Timer must be
 *		periodically refreshed by reading the same I/O port 443h.
 *		The Watch-Dog Timer is disabled by reading I/O port 043h.
 *
 *		The Watch-Dog Timer Time-Out Period is set via jumpers.
 *		It can be 1, 2, 10, 20, 110 or 220 seconds.
 */

/*
 *	Includes, defines, variables, module parameters, ...
 */

/* Includes */
#include <linux/module.h>		/* For module specific items */
#include <linux/moduleparam.h>		/* For new moduleparam's */
#include <linux/types.h>		/* For standard types (like size_t) */
#include <linux/errno.h>		/* For the -ENODEV/... values */
#include <linux/kernel.h>		/* For printk/panic/... */
#include <linux/miscdevice.h>		/* For MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) */
#include <linux/watchdog.h>		/* For the watchdog specific items */
#include <linux/fs.h>			/* For file operations */
#include <linux/ioport.h>		/* For io-port access */
#include <linux/platform_device.h>	/* For platform_driver framework */
#include <linux/init.h>			/* For __init/__exit/... */

#include <asm/uaccess.h>		/* For copy_to_user/put_user/... */
#include <asm/io.h>			/* For inb/outb/... */

/* Module information */
#define DRV_NAME "acquirewdt"
#define PFX DRV_NAME ": "
#define WATCHDOG_NAME "Acquire WDT"
#define WATCHDOG_HEARTBEAT 0	/* There is no way to see what the correct time-out period is */

/* internal variables */
static struct platform_device *acq_platform_device;	/* the watchdog platform device */
static unsigned long acq_is_open;
static char expect_close;

/* module parameters */
static int wdt_stop = 0x43;	/* You must set this - there is no sane way to probe for this board. */
module_param(wdt_stop, int, 0);
MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");

static int wdt_start = 0x443;	/* You must set this - there is no sane way to probe for this board. */
module_param(wdt_start, int, 0);
MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

/*
 *	Watchdog Operations
 */

static void acq_keepalive(void)
{
	/* Write a watchdog value */
	inb_p(wdt_start);
}

static void acq_stop(void)
{
	/* Turn the card off */
	inb_p(wdt_stop);
}

/*
 *	/dev/watchdog handling
 */

static ssize_t acq_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
	/* See if we got the magic character 'V' and reload the timer */
	if(count) {
		if (!nowayout) {
			size_t i;

			/* note: just in case someone wrote the magic character
			 * five months ago... */
			expect_close = 0;

			/* scan to see whether or not we got the magic character */
			for (i = 0; i != count; i++) {
				char c;
				if (get_user(c, buf + i))
					return -EFAULT;
				if (c == 'V')
					expect_close = 42;
			}
		}

		/* Well, anyhow someone wrote to us, we should return that favour */
		acq_keepalive();
	}
	return count;
}

static int acq_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
	unsigned long arg)
{
	int options, retval = -EINVAL;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static struct watchdog_info ident =
	{
		.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
		.firmware_version = 1,
		.identity = WATCHDOG_NAME,
	};

	switch(cmd)
	{
	case WDIOC_GETSUPPORT:
	  return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	  return put_user(0, p);

	case WDIOC_KEEPALIVE:
	  acq_keepalive();
	  return 0;

	case WDIOC_GETTIMEOUT:
	  return put_user(WATCHDOG_HEARTBEAT, p);

	case WDIOC_SETOPTIONS:
	{
	    if (get_user(options, p))
	      return -EFAULT;

	    if (options & WDIOS_DISABLECARD)
	    {
	      acq_stop();
	      retval = 0;
	    }

	    if (options & WDIOS_ENABLECARD)
	    {
	      acq_keepalive();
	      retval = 0;
	    }

	    return retval;
	}

	default:
	  return -ENOTTY;
	}
}

static int acq_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &acq_is_open))
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	/* Activate */
	acq_keepalive();
	return nonseekable_open(inode, file);
}

static int acq_close(struct inode *inode, struct file *file)
{
	if (expect_close == 42) {
		acq_stop();
	} else {
		printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
		acq_keepalive();
	}
	clear_bit(0, &acq_is_open);
	expect_close = 0;
	return 0;
}

/*
 *	Kernel Interfaces
 */

static const struct file_operations acq_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= acq_write,
	.ioctl		= acq_ioctl,
	.open		= acq_open,
	.release	= acq_close,
};

static struct miscdevice acq_miscdev = {
	.minor	= WATCHDOG_MINOR,
	.name	= "watchdog",
	.fops	= &acq_fops,
};

/*
 *	Init & exit routines
 */

static int __devinit acq_probe(struct platform_device *dev)
{
	int ret;

	if (wdt_stop != wdt_start) {
		if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
			printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
				wdt_stop);
			ret = -EIO;
			goto out;
		}
	}

	if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
		printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
			wdt_start);
		ret = -EIO;
		goto unreg_stop;
	}

	ret = misc_register(&acq_miscdev);
	if (ret != 0) {
		printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
			WATCHDOG_MINOR, ret);
		goto unreg_regions;
	}

	printk (KERN_INFO PFX "initialized. (nowayout=%d)\n",
		nowayout);

	return 0;

unreg_regions:
	release_region(wdt_start, 1);
unreg_stop:
	if (wdt_stop != wdt_start)
		release_region(wdt_stop, 1);
out:
	return ret;
}

static int __devexit acq_remove(struct platform_device *dev)
{
	misc_deregister(&acq_miscdev);
	release_region(wdt_start,1);
	if(wdt_stop != wdt_start)
		release_region(wdt_stop,1);

	return 0;
}

static void acq_shutdown(struct platform_device *dev)
{
	/* Turn the WDT off if we have a soft shutdown */
	acq_stop();
}

static struct platform_driver acquirewdt_driver = {
	.probe		= acq_probe,
	.remove		= __devexit_p(acq_remove),
	.shutdown	= acq_shutdown,
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= DRV_NAME,
	},
};

static int __init acq_init(void)
{
	int err;

	printk(KERN_INFO "WDT driver for Acquire single board computer initialising.\n");

	err = platform_driver_register(&acquirewdt_driver);
	if (err)
		return err;

	acq_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
	if (IS_ERR(acq_platform_device)) {
		err = PTR_ERR(acq_platform_device);
		goto unreg_platform_driver;
	}

	return 0;

unreg_platform_driver:
	platform_driver_unregister(&acquirewdt_driver);
	return err;
}

static void __exit acq_exit(void)
{
	platform_device_unregister(acq_platform_device);
	platform_driver_unregister(&acquirewdt_driver);
	printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
}

module_init(acq_init);
module_exit(acq_exit);

MODULE_AUTHOR("David Woodhouse");
MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
1da177e4 LT	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@redhat.com>, All Rights Reserved.
	7	* http://www.redhat.com
	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@redhat.com>
	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 occured 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
76c11f04 WVS	51	/*
	52	* Includes, defines, variables, module parameters, ...
	53	*/
1da177e4	54
76c11f04 WVS	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(WATCHDOG_MINOR) */
	62	#include <linux/watchdog.h> /* For the watchdog specific items */
	63	#include <linux/fs.h> /* For file operations */
	64	#include <linux/ioport.h> /* For io-port access */
ad5fe323	65	#include <linux/platform_device.h> /* For platform_driver framework */
76c11f04 WVS	66	#include <linux/init.h> /* For __init/__exit/... */
	67
	68	#include <asm/uaccess.h> /* For copy_to_user/put_user/... */
	69	#include <asm/io.h> /* For inb/outb/... */
	70
	71	/* Module information */
	72	#define DRV_NAME "acquirewdt"
	73	#define PFX DRV_NAME ": "
1da177e4	74	#define WATCHDOG_NAME "Acquire WDT"
1da177e4 LT	75	#define WATCHDOG_HEARTBEAT 0 /* There is no way to see what the correct time-out period is */
1da177e4 LT	76
76c11f04	77	/* internal variables */
ad5fe323	78	static struct platform_device acq_platform_device; / the watchdog platform device */
1da177e4 LT	79	static unsigned long acq_is_open;
	80	static char expect_close;
	81
76c11f04 WVS	82	/* module parameters */
76c11f04 WVS	83	static int wdt_stop = 0x43; /* You must set this - there is no sane way to probe for this board. */
1da177e4 LT	84	module_param(wdt_stop, int, 0);
	85	MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");
	86
76c11f04	87	static int wdt_start = 0x443; /* You must set this - there is no sane way to probe for this board. */
1da177e4 LT	88	module_param(wdt_start, int, 0);
	89	MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");
	90
4bfdf378	91	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4	92	module_param(nowayout, int, 0);
76c11f04	93	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4 LT	94
1da177e4 LT	95	/*
76c11f04	96	* Watchdog Operations
1da177e4 LT	97	*/
	98
	99	static void acq_keepalive(void)
	100	{
	101	/* Write a watchdog value */
	102	inb_p(wdt_start);
	103	}
	104
	105	static void acq_stop(void)
	106	{
	107	/* Turn the card off */
	108	inb_p(wdt_stop);
	109	}
	110
	111	/*
76c11f04	112	* /dev/watchdog handling
1da177e4 LT	113	*/
	114
	115	static ssize_t acq_write(struct file file, const char __user buf, size_t count, loff_t *ppos)
	116	{
	117	/* See if we got the magic character 'V' and reload the timer */
	118	if(count) {
	119	if (!nowayout) {
	120	size_t i;
	121
	122	/* note: just in case someone wrote the magic character
	123	* five months ago... */
	124	expect_close = 0;
	125
	126	/* scan to see whether or not we got the magic character */
	127	for (i = 0; i != count; i++) {
	128	char c;
	129	if (get_user(c, buf + i))
	130	return -EFAULT;
	131	if (c == 'V')
	132	expect_close = 42;
	133	}
	134	}
	135
	136	/* Well, anyhow someone wrote to us, we should return that favour */
	137	acq_keepalive();
	138	}
	139	return count;
	140	}
	141
	142	static int acq_ioctl(struct inode inode, struct file file, unsigned int cmd,
	143	unsigned long arg)
	144	{
	145	int options, retval = -EINVAL;
	146	void __user argp = (void __user )arg;
	147	int __user *p = argp;
	148	static struct watchdog_info ident =
	149	{
	150	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	151	.firmware_version = 1,
76c11f04	152	.identity = WATCHDOG_NAME,
1da177e4 LT	153	};
	154
	155	switch(cmd)
	156	{
	157	case WDIOC_GETSUPPORT:
	158	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	159
	160	case WDIOC_GETSTATUS:
	161	case WDIOC_GETBOOTSTATUS:
	162	return put_user(0, p);
	163
	164	case WDIOC_KEEPALIVE:
	165	acq_keepalive();
	166	return 0;
	167
	168	case WDIOC_GETTIMEOUT:
	169	return put_user(WATCHDOG_HEARTBEAT, p);
	170
	171	case WDIOC_SETOPTIONS:
	172	{
	173	if (get_user(options, p))
	174	return -EFAULT;
	175
	176	if (options & WDIOS_DISABLECARD)
	177	{
	178	acq_stop();
	179	retval = 0;
	180	}
	181
	182	if (options & WDIOS_ENABLECARD)
	183	{
	184	acq_keepalive();
	185	retval = 0;
	186	}
	187
	188	return retval;
	189	}
	190
	191	default:
795b89d2	192	return -ENOTTY;
1da177e4 LT	193	}
	194	}
	195
	196	static int acq_open(struct inode inode, struct file file)
	197	{
	198	if (test_and_set_bit(0, &acq_is_open))
	199	return -EBUSY;
	200
	201	if (nowayout)
	202	__module_get(THIS_MODULE);
	203
	204	/* Activate */
	205	acq_keepalive();
	206	return nonseekable_open(inode, file);
	207	}
	208
	209	static int acq_close(struct inode inode, struct file file)
	210	{
	211	if (expect_close == 42) {
	212	acq_stop();
	213	} else {
	214	printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
	215	acq_keepalive();
	216	}
	217	clear_bit(0, &acq_is_open);
	218	expect_close = 0;
	219	return 0;
	220	}
	221
1da177e4 LT	222	/*
	223	* Kernel Interfaces
	224	*/
	225
62322d25	226	static const struct file_operations acq_fops = {
1da177e4 LT	227	.owner = THIS_MODULE,
	228	.llseek = no_llseek,
	229	.write = acq_write,
	230	.ioctl = acq_ioctl,
	231	.open = acq_open,
	232	.release = acq_close,
	233	};
	234
76c11f04 WVS	235	static struct miscdevice acq_miscdev = {
	236	.minor = WATCHDOG_MINOR,
	237	.name = "watchdog",
	238	.fops = &acq_fops,
1da177e4 LT	239	};
1da177e4 LT	240
76c11f04 WVS	241	/*
	242	* Init & exit routines
	243	*/
	244
ad5fe323	245	static int __devinit acq_probe(struct platform_device *dev)
1da177e4 LT	246	{
	247	int ret;
	248
1da177e4 LT	249	if (wdt_stop != wdt_start) {
	250	if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
	251	printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
	252	wdt_stop);
	253	ret = -EIO;
	254	goto out;
	255	}
	256	}
	257
	258	if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
	259	printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
	260	wdt_start);
	261	ret = -EIO;
	262	goto unreg_stop;
	263	}
	264
1da177e4 LT	265	ret = misc_register(&acq_miscdev);
	266	if (ret != 0) {
	267	printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
	268	WATCHDOG_MINOR, ret);
98c08e98	269	goto unreg_regions;
1da177e4 LT	270	}
	271
	272	printk (KERN_INFO PFX "initialized. (nowayout=%d)\n",
	273	nowayout);
	274
	275	return 0;
	276
1da177e4 LT	277	unreg_regions:
	278	release_region(wdt_start, 1);
	279	unreg_stop:
	280	if (wdt_stop != wdt_start)
	281	release_region(wdt_stop, 1);
	282	out:
	283	return ret;
	284	}
	285
ad5fe323	286	static int __devexit acq_remove(struct platform_device *dev)
1da177e4 LT	287	{
1da177e4 LT	288	misc_deregister(&acq_miscdev);
76c11f04	289	release_region(wdt_start,1);
1da177e4 LT	290	if(wdt_stop != wdt_start)
1da177e4 LT	291	release_region(wdt_stop,1);
ad5fe323 WVS	292
	293	return 0;
	294	}
	295
98c08e98 WVS	296	static void acq_shutdown(struct platform_device *dev)
	297	{
	298	/* Turn the WDT off if we have a soft shutdown */
	299	acq_stop();
	300	}
	301
ad5fe323 WVS	302	static struct platform_driver acquirewdt_driver = {
	303	.probe = acq_probe,
	304	.remove = __devexit_p(acq_remove),
98c08e98	305	.shutdown = acq_shutdown,
ad5fe323 WVS	306	.driver = {
	307	.owner = THIS_MODULE,
	308	.name = DRV_NAME,
	309	},
	310	};
	311
	312	static int __init acq_init(void)
	313	{
	314	int err;
	315
	316	printk(KERN_INFO "WDT driver for Acquire single board computer initialising.\n");
	317
	318	err = platform_driver_register(&acquirewdt_driver);
	319	if (err)
	320	return err;
	321
	322	acq_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
	323	if (IS_ERR(acq_platform_device)) {
	324	err = PTR_ERR(acq_platform_device);
	325	goto unreg_platform_driver;
	326	}
	327
	328	return 0;
	329
	330	unreg_platform_driver:
	331	platform_driver_unregister(&acquirewdt_driver);
	332	return err;
	333	}
	334
	335	static void __exit acq_exit(void)
	336	{
	337	platform_device_unregister(acq_platform_device);
	338	platform_driver_unregister(&acquirewdt_driver);
	339	printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
1da177e4 LT	340	}
	341
	342	module_init(acq_init);
	343	module_exit(acq_exit);
	344
	345	MODULE_AUTHOR("David Woodhouse");
	346	MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
	347	MODULE_LICENSE("GPL");
	348	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);