[linux.git] / drivers / watchdog / acquirewdt.c

/*
 *	Acquire Single Board Computer Watchdog Timer driver
 *
 *	Based on wdt.c. Original copyright messages:
 *
 *	(c) Copyright 1996 Alan Cox <[email protected]>,
 *						All Rights Reserved.
 *
 *	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 <[email protected]>
 *
 *	14-Dec-2001 Matt Domsch <[email protected]>
 *	    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 occurred 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, ...
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

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

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

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

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

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 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 long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	int options, retval = -EINVAL;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static const 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_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;
	}
	case WDIOC_KEEPALIVE:
		acq_keepalive();
		return 0;

	case WDIOC_GETTIMEOUT:
		return put_user(WATCHDOG_HEARTBEAT, p);

	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 {
		pr_crit("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,
	.unlocked_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 acq_probe(struct platform_device *dev)
{
	int ret;

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

	if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
		pr_err("I/O address 0x%04x already in use\n", wdt_start);
		ret = -EIO;
		goto unreg_stop;
	}
	ret = misc_register(&acq_miscdev);
	if (ret != 0) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       WATCHDOG_MINOR, ret);
		goto unreg_regions;
	}
	pr_info("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 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		= acq_remove,
	.shutdown	= acq_shutdown,
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= DRV_NAME,
	},
};

static int __init acq_init(void)
{
	int err;

	pr_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);
	pr_info("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	*
143a2e54	4	* Based on wdt.c. Original copyright messages:
1da177e4	5	*
29fa0586 AC	6	* (c) Copyright 1996 Alan Cox <[email protected]>,
29fa0586 AC	7	* All Rights Reserved.
1da177e4 LT	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	*
29fa0586	18	* (c) Copyright 1995 Alan Cox <[email protected]>
1da177e4	19	*
143a2e54 WVS	20	* 14-Dec-2001 Matt Domsch <[email protected]>
	21	* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
	22	* Can't add timeout - driver doesn't allow changing value
1da177e4 LT	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
25985edc	29	* caused the CPU to crash. This condition may have occurred by
1da177e4 LT	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
27c766aa JP	55	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	56
76c11f04 WVS	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/... */
94da1e2e AC	63	#include <linux/miscdevice.h> /* For MODULE_ALIAS_MISCDEV
94da1e2e AC	64	(WATCHDOG_MINOR) */
76c11f04 WVS	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 */
ad5fe323	68	#include <linux/platform_device.h> /* For platform_driver framework */
76c11f04	69	#include <linux/init.h> /* For __init/__exit/... */
94da1e2e AC	70	#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
94da1e2e AC	71	#include <linux/io.h> /* For inb/outb/... */
76c11f04 WVS	72
	73	/* Module information */
	74	#define DRV_NAME "acquirewdt"
1da177e4	75	#define WATCHDOG_NAME "Acquire WDT"
94da1e2e AC	76	/* There is no way to see what the correct time-out period is */
94da1e2e AC	77	#define WATCHDOG_HEARTBEAT 0
1da177e4	78
76c11f04	79	/* internal variables */
94da1e2e AC	80	/* the watchdog platform device */
94da1e2e AC	81	static struct platform_device *acq_platform_device;
1da177e4 LT	82	static unsigned long acq_is_open;
	83	static char expect_close;
	84
76c11f04	85	/* module parameters */
94da1e2e AC	86	/* You must set this - there is no sane way to probe for this board. */
94da1e2e AC	87	static int wdt_stop = 0x43;
1da177e4 LT	88	module_param(wdt_stop, int, 0);
	89	MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");
	90
94da1e2e AC	91	/* You must set this - there is no sane way to probe for this board. */
94da1e2e AC	92	static int wdt_start = 0x443;
1da177e4 LT	93	module_param(wdt_start, int, 0);
	94	MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");
	95
86a1e189 WVS	96	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	97	module_param(nowayout, bool, 0);
94da1e2e AC	98	MODULE_PARM_DESC(nowayout,
	99	"Watchdog cannot be stopped once started (default="
	100	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4 LT	101
1da177e4 LT	102	/*
76c11f04	103	* Watchdog Operations
1da177e4 LT	104	*/
	105
	106	static void acq_keepalive(void)
	107	{
	108	/* Write a watchdog value */
	109	inb_p(wdt_start);
	110	}
	111
	112	static void acq_stop(void)
	113	{
	114	/* Turn the card off */
	115	inb_p(wdt_stop);
	116	}
	117
	118	/*
76c11f04	119	* /dev/watchdog handling
1da177e4 LT	120	*/
1da177e4 LT	121
94da1e2e AC	122	static ssize_t acq_write(struct file file, const char __user buf,
94da1e2e AC	123	size_t count, loff_t *ppos)
1da177e4 LT	124	{
1da177e4 LT	125	/* See if we got the magic character 'V' and reload the timer */
94da1e2e	126	if (count) {
1da177e4 LT	127	if (!nowayout) {
1da177e4 LT	128	size_t i;
1da177e4	129	/* note: just in case someone wrote the magic character
7944d3a5	130	five months ago... */
1da177e4	131	expect_close = 0;
94da1e2e AC	132	/* scan to see whether or not we got the
94da1e2e AC	133	magic character */
1da177e4 LT	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	}
94da1e2e AC	142	/* Well, anyhow someone wrote to us, we should
94da1e2e AC	143	return that favour */
1da177e4 LT	144	acq_keepalive();
	145	}
	146	return count;
	147	}
	148
94da1e2e	149	static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 LT	150	{
	151	int options, retval = -EINVAL;
	152	void __user argp = (void __user )arg;
	153	int __user *p = argp;
42747d71	154	static const struct watchdog_info ident = {
1da177e4 LT	155	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
1da177e4 LT	156	.firmware_version = 1,
76c11f04	157	.identity = WATCHDOG_NAME,
1da177e4 LT	158	};
1da177e4 LT	159
94da1e2e	160	switch (cmd) {
1da177e4	161	case WDIOC_GETSUPPORT:
94da1e2e	162	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
1da177e4 LT	163
	164	case WDIOC_GETSTATUS:
	165	case WDIOC_GETBOOTSTATUS:
94da1e2e	166	return put_user(0, p);
1da177e4	167
1da177e4 LT	168	case WDIOC_SETOPTIONS:
1da177e4 LT	169	{
94da1e2e AC	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;
1da177e4	181	}
0c06090c WVS	182	case WDIOC_KEEPALIVE:
	183	acq_keepalive();
	184	return 0;
	185
	186	case WDIOC_GETTIMEOUT:
	187	return put_user(WATCHDOG_HEARTBEAT, p);
	188
1da177e4	189	default:
94da1e2e	190	return -ENOTTY;
1da177e4 LT	191	}
	192	}
	193
	194	static 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
	207	static int acq_close(struct inode inode, struct file file)
	208	{
	209	if (expect_close == 42) {
	210	acq_stop();
	211	} else {
27c766aa	212	pr_crit("Unexpected close, not stopping watchdog!\n");
1da177e4 LT	213	acq_keepalive();
	214	}
	215	clear_bit(0, &acq_is_open);
	216	expect_close = 0;
	217	return 0;
	218	}
	219
1da177e4 LT	220	/*
	221	* Kernel Interfaces
	222	*/
	223
62322d25	224	static const struct file_operations acq_fops = {
1da177e4 LT	225	.owner = THIS_MODULE,
	226	.llseek = no_llseek,
	227	.write = acq_write,
94da1e2e	228	.unlocked_ioctl = acq_ioctl,
1da177e4 LT	229	.open = acq_open,
	230	.release = acq_close,
	231	};
	232
76c11f04 WVS	233	static struct miscdevice acq_miscdev = {
	234	.minor = WATCHDOG_MINOR,
	235	.name = "watchdog",
	236	.fops = &acq_fops,
1da177e4 LT	237	};
1da177e4 LT	238
76c11f04 WVS	239	/*
	240	* Init & exit routines
	241	*/
	242
2d991a16	243	static int acq_probe(struct platform_device *dev)
1da177e4 LT	244	{
	245	int ret;
	246
1da177e4 LT	247	if (wdt_stop != wdt_start) {
1da177e4 LT	248	if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
27c766aa	249	pr_err("I/O address 0x%04x already in use\n", wdt_stop);
1da177e4 LT	250	ret = -EIO;
	251	goto out;
	252	}
	253	}
	254
	255	if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
27c766aa	256	pr_err("I/O address 0x%04x already in use\n", wdt_start);
1da177e4 LT	257	ret = -EIO;
	258	goto unreg_stop;
	259	}
1da177e4 LT	260	ret = misc_register(&acq_miscdev);
1da177e4 LT	261	if (ret != 0) {
27c766aa JP	262	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
27c766aa JP	263	WATCHDOG_MINOR, ret);
98c08e98	264	goto unreg_regions;
1da177e4	265	}
27c766aa	266	pr_info("initialized. (nowayout=%d)\n", nowayout);
1da177e4 LT	267
1da177e4 LT	268	return 0;
1da177e4 LT	269	unreg_regions:
	270	release_region(wdt_start, 1);
	271	unreg_stop:
	272	if (wdt_stop != wdt_start)
	273	release_region(wdt_stop, 1);
	274	out:
	275	return ret;
	276	}
	277
4b12b896	278	static int acq_remove(struct platform_device *dev)
1da177e4 LT	279	{
1da177e4 LT	280	misc_deregister(&acq_miscdev);
94da1e2e AC	281	release_region(wdt_start, 1);
	282	if (wdt_stop != wdt_start)
	283	release_region(wdt_stop, 1);
ad5fe323 WVS	284
	285	return 0;
	286	}
	287
98c08e98 WVS	288	static void acq_shutdown(struct platform_device *dev)
	289	{
	290	/* Turn the WDT off if we have a soft shutdown */
	291	acq_stop();
	292	}
	293
ad5fe323 WVS	294	static struct platform_driver acquirewdt_driver = {
ad5fe323 WVS	295	.probe = acq_probe,
82268714	296	.remove = acq_remove,
98c08e98	297	.shutdown = acq_shutdown,
ad5fe323 WVS	298	.driver = {
	299	.owner = THIS_MODULE,
	300	.name = DRV_NAME,
	301	},
	302	};
	303
	304	static int __init acq_init(void)
	305	{
	306	int err;
	307
27c766aa	308	pr_info("WDT driver for Acquire single board computer initialising\n");
ad5fe323 WVS	309
	310	err = platform_driver_register(&acquirewdt_driver);
	311	if (err)
	312	return err;
	313
94da1e2e AC	314	acq_platform_device = platform_device_register_simple(DRV_NAME,
94da1e2e AC	315	-1, NULL, 0);
ad5fe323 WVS	316	if (IS_ERR(acq_platform_device)) {
	317	err = PTR_ERR(acq_platform_device);
	318	goto unreg_platform_driver;
	319	}
ad5fe323 WVS	320	return 0;
	321
	322	unreg_platform_driver:
	323	platform_driver_unregister(&acquirewdt_driver);
	324	return err;
	325	}
	326
	327	static void __exit acq_exit(void)
	328	{
	329	platform_device_unregister(acq_platform_device);
	330	platform_driver_unregister(&acquirewdt_driver);
27c766aa	331	pr_info("Watchdog Module Unloaded\n");
1da177e4 LT	332	}
	333
	334	module_init(acq_init);
	335	module_exit(acq_exit);
	336
	337	MODULE_AUTHOR("David Woodhouse");
	338	MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
	339	MODULE_LICENSE("GPL");
	340	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);