[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 struct miscdevice */
#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 __init 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 = {
	.remove		= acq_remove,
	.shutdown	= acq_shutdown,
	.driver		= {
		.name	= DRV_NAME,
	},
};

static int __init acq_init(void)
{
	int err;

	pr_info("WDT driver for Acquire single board computer initialising\n");

	acq_platform_device = platform_device_register_simple(DRV_NAME,
								-1, NULL, 0);
	if (IS_ERR(acq_platform_device))
		return PTR_ERR(acq_platform_device);

	err = platform_driver_probe(&acquirewdt_driver, acq_probe);
	if (err)
		goto unreg_platform_device;
	return 0;

unreg_platform_device:
	platform_device_unregister(acq_platform_device);
	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");
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/... */
487722cf	63	#include <linux/miscdevice.h> /* For struct miscdevice */
76c11f04 WVS	64	#include <linux/watchdog.h> /* For the watchdog specific items */
	65	#include <linux/fs.h> /* For file operations */
	66	#include <linux/ioport.h> /* For io-port access */
ad5fe323	67	#include <linux/platform_device.h> /* For platform_driver framework */
76c11f04	68	#include <linux/init.h> /* For __init/__exit/... */
94da1e2e AC	69	#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
94da1e2e AC	70	#include <linux/io.h> /* For inb/outb/... */
76c11f04 WVS	71
	72	/* Module information */
	73	#define DRV_NAME "acquirewdt"
1da177e4	74	#define WATCHDOG_NAME "Acquire WDT"
94da1e2e AC	75	/* There is no way to see what the correct time-out period is */
94da1e2e AC	76	#define WATCHDOG_HEARTBEAT 0
1da177e4	77
76c11f04	78	/* internal variables */
94da1e2e AC	79	/* the watchdog platform device */
94da1e2e AC	80	static struct platform_device *acq_platform_device;
1da177e4 LT	81	static unsigned long acq_is_open;
	82	static char expect_close;
	83
76c11f04	84	/* module parameters */
94da1e2e AC	85	/* You must set this - there is no sane way to probe for this board. */
94da1e2e AC	86	static int wdt_stop = 0x43;
1da177e4 LT	87	module_param(wdt_stop, int, 0);
	88	MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");
	89
94da1e2e AC	90	/* You must set this - there is no sane way to probe for this board. */
94da1e2e AC	91	static int wdt_start = 0x443;
1da177e4 LT	92	module_param(wdt_start, int, 0);
	93	MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");
	94
86a1e189 WVS	95	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	96	module_param(nowayout, bool, 0);
94da1e2e AC	97	MODULE_PARM_DESC(nowayout,
	98	"Watchdog cannot be stopped once started (default="
	99	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4 LT	100
1da177e4 LT	101	/*
76c11f04	102	* Watchdog Operations
1da177e4 LT	103	*/
	104
	105	static void acq_keepalive(void)
	106	{
	107	/* Write a watchdog value */
	108	inb_p(wdt_start);
	109	}
	110
	111	static void acq_stop(void)
	112	{
	113	/* Turn the card off */
	114	inb_p(wdt_stop);
	115	}
	116
	117	/*
76c11f04	118	* /dev/watchdog handling
1da177e4 LT	119	*/
1da177e4 LT	120
94da1e2e AC	121	static ssize_t acq_write(struct file file, const char __user buf,
94da1e2e AC	122	size_t count, loff_t *ppos)
1da177e4 LT	123	{
1da177e4 LT	124	/* See if we got the magic character 'V' and reload the timer */
94da1e2e	125	if (count) {
1da177e4 LT	126	if (!nowayout) {
1da177e4 LT	127	size_t i;
1da177e4	128	/* note: just in case someone wrote the magic character
7944d3a5	129	five months ago... */
1da177e4	130	expect_close = 0;
94da1e2e AC	131	/* scan to see whether or not we got the
94da1e2e AC	132	magic character */
1da177e4 LT	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	}
94da1e2e AC	141	/* Well, anyhow someone wrote to us, we should
94da1e2e AC	142	return that favour */
1da177e4 LT	143	acq_keepalive();
	144	}
	145	return count;
	146	}
	147
94da1e2e	148	static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 LT	149	{
	150	int options, retval = -EINVAL;
	151	void __user argp = (void __user )arg;
	152	int __user *p = argp;
42747d71	153	static const struct watchdog_info ident = {
1da177e4 LT	154	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
1da177e4 LT	155	.firmware_version = 1,
76c11f04	156	.identity = WATCHDOG_NAME,
1da177e4 LT	157	};
1da177e4 LT	158
94da1e2e	159	switch (cmd) {
1da177e4	160	case WDIOC_GETSUPPORT:
94da1e2e	161	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
1da177e4 LT	162
	163	case WDIOC_GETSTATUS:
	164	case WDIOC_GETBOOTSTATUS:
94da1e2e	165	return put_user(0, p);
1da177e4	166
1da177e4 LT	167	case WDIOC_SETOPTIONS:
1da177e4 LT	168	{
94da1e2e AC	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;
1da177e4	180	}
0c06090c WVS	181	case WDIOC_KEEPALIVE:
	182	acq_keepalive();
	183	return 0;
	184
	185	case WDIOC_GETTIMEOUT:
	186	return put_user(WATCHDOG_HEARTBEAT, p);
	187
1da177e4	188	default:
94da1e2e	189	return -ENOTTY;
1da177e4 LT	190	}
	191	}
	192
	193	static 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
	206	static int acq_close(struct inode inode, struct file file)
	207	{
	208	if (expect_close == 42) {
	209	acq_stop();
	210	} else {
27c766aa	211	pr_crit("Unexpected close, not stopping watchdog!\n");
1da177e4 LT	212	acq_keepalive();
	213	}
	214	clear_bit(0, &acq_is_open);
	215	expect_close = 0;
	216	return 0;
	217	}
	218
1da177e4 LT	219	/*
	220	* Kernel Interfaces
	221	*/
	222
62322d25	223	static const struct file_operations acq_fops = {
1da177e4 LT	224	.owner = THIS_MODULE,
	225	.llseek = no_llseek,
	226	.write = acq_write,
94da1e2e	227	.unlocked_ioctl = acq_ioctl,
1da177e4 LT	228	.open = acq_open,
	229	.release = acq_close,
	230	};
	231
76c11f04 WVS	232	static struct miscdevice acq_miscdev = {
	233	.minor = WATCHDOG_MINOR,
	234	.name = "watchdog",
	235	.fops = &acq_fops,
1da177e4 LT	236	};
1da177e4 LT	237
76c11f04 WVS	238	/*
	239	* Init & exit routines
	240	*/
	241
b0e0b4b5	242	static int __init acq_probe(struct platform_device *dev)
1da177e4 LT	243	{
	244	int ret;
	245
1da177e4 LT	246	if (wdt_stop != wdt_start) {
1da177e4 LT	247	if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
27c766aa	248	pr_err("I/O address 0x%04x already in use\n", wdt_stop);
1da177e4 LT	249	ret = -EIO;
	250	goto out;
	251	}
	252	}
	253
	254	if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
27c766aa	255	pr_err("I/O address 0x%04x already in use\n", wdt_start);
1da177e4 LT	256	ret = -EIO;
	257	goto unreg_stop;
	258	}
1da177e4 LT	259	ret = misc_register(&acq_miscdev);
1da177e4 LT	260	if (ret != 0) {
27c766aa JP	261	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
27c766aa JP	262	WATCHDOG_MINOR, ret);
98c08e98	263	goto unreg_regions;
1da177e4	264	}
27c766aa	265	pr_info("initialized. (nowayout=%d)\n", nowayout);
1da177e4 LT	266
1da177e4 LT	267	return 0;
1da177e4 LT	268	unreg_regions:
	269	release_region(wdt_start, 1);
	270	unreg_stop:
	271	if (wdt_stop != wdt_start)
	272	release_region(wdt_stop, 1);
	273	out:
	274	return ret;
	275	}
	276
4b12b896	277	static int acq_remove(struct platform_device *dev)
1da177e4 LT	278	{
1da177e4 LT	279	misc_deregister(&acq_miscdev);
94da1e2e AC	280	release_region(wdt_start, 1);
	281	if (wdt_stop != wdt_start)
	282	release_region(wdt_stop, 1);
ad5fe323 WVS	283
	284	return 0;
	285	}
	286
98c08e98 WVS	287	static void acq_shutdown(struct platform_device *dev)
	288	{
	289	/* Turn the WDT off if we have a soft shutdown */
	290	acq_stop();
	291	}
	292
ad5fe323	293	static struct platform_driver acquirewdt_driver = {
82268714	294	.remove = acq_remove,
98c08e98	295	.shutdown = acq_shutdown,
ad5fe323	296	.driver = {
ad5fe323 WVS	297	.name = DRV_NAME,
	298	},
	299	};
	300
	301	static int __init acq_init(void)
	302	{
	303	int err;
	304
27c766aa	305	pr_info("WDT driver for Acquire single board computer initialising\n");
ad5fe323	306
94da1e2e AC	307	acq_platform_device = platform_device_register_simple(DRV_NAME,
94da1e2e AC	308	-1, NULL, 0);
b0e0b4b5 JD	309	if (IS_ERR(acq_platform_device))
	310	return PTR_ERR(acq_platform_device);
	311
	312	err = platform_driver_probe(&acquirewdt_driver, acq_probe);
	313	if (err)
	314	goto unreg_platform_device;
ad5fe323 WVS	315	return 0;
ad5fe323 WVS	316
b0e0b4b5 JD	317	unreg_platform_device:
b0e0b4b5 JD	318	platform_device_unregister(acq_platform_device);
ad5fe323 WVS	319	return err;
	320	}
	321
	322	static void __exit acq_exit(void)
	323	{
	324	platform_device_unregister(acq_platform_device);
	325	platform_driver_unregister(&acquirewdt_driver);
27c766aa	326	pr_info("Watchdog Module Unloaded\n");
1da177e4 LT	327	}
	328
	329	module_init(acq_init);
	330	module_exit(acq_exit);
	331
	332	MODULE_AUTHOR("David Woodhouse");
	333	MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
	334	MODULE_LICENSE("GPL");