[mirror_ubuntu-hirsute-kernel.git] / drivers / watchdog / acquirewdt.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *	Acquire Single Board Computer Watchdog Timer driver
 *
 *	Based on wdt.c. Original copyright messages:
 *
 *	(c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
 *						All Rights Reserved.
 *
 *	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@lxorguk.ukuu.org.uk>
 *
 *	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 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 stream_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,
	.compat_ioctl	= compat_ptr_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
d0173278	1	// SPDX-License-Identifier: GPL-2.0+
1da177e4 LT	2	/*
	3	* Acquire Single Board Computer Watchdog Timer driver
	4	*
143a2e54	5	* Based on wdt.c. Original copyright messages:
1da177e4	6	*
29fa0586 AC	7	* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
29fa0586 AC	8	* All Rights Reserved.
1da177e4	9	*
1da177e4 LT	10	* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
	11	* warranty for any of this software. This material is provided
	12	* "AS-IS" and at no charge.
	13	*
29fa0586	14	* (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
1da177e4	15	*
143a2e54 WVS	16	* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
	17	* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
	18	* Can't add timeout - driver doesn't allow changing value
1da177e4 LT	19	*/
	20
	21	/*
	22	* Theory of Operation:
	23	* The Watch-Dog Timer is provided to ensure that standalone
	24	* Systems can always recover from catastrophic conditions that
25985edc	25	* caused the CPU to crash. This condition may have occurred by
1da177e4 LT	26	* external EMI or a software bug. When the CPU stops working
	27	* correctly, hardware on the board will either perform a hardware
	28	* reset (cold boot) or a non-maskable interrupt (NMI) to bring the
	29	* system back to a known state.
	30	*
	31	* The Watch-Dog Timer is controlled by two I/O Ports.
	32	* 443 hex - Read - Enable or refresh the Watch-Dog Timer
	33	* 043 hex - Read - Disable the Watch-Dog Timer
	34	*
	35	* To enable the Watch-Dog Timer, a read from I/O port 443h must
	36	* be performed. This will enable and activate the countdown timer
	37	* which will eventually time out and either reset the CPU or cause
	38	* an NMI depending on the setting of a jumper. To ensure that this
	39	* reset condition does not occur, the Watch-Dog Timer must be
	40	* periodically refreshed by reading the same I/O port 443h.
	41	* The Watch-Dog Timer is disabled by reading I/O port 043h.
	42	*
	43	* The Watch-Dog Timer Time-Out Period is set via jumpers.
	44	* It can be 1, 2, 10, 20, 110 or 220 seconds.
	45	*/
	46
76c11f04 WVS	47	/*
	48	* Includes, defines, variables, module parameters, ...
	49	*/
1da177e4	50
27c766aa JP	51	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	52
76c11f04 WVS	53	/* Includes */
	54	#include <linux/module.h> /* For module specific items */
	55	#include <linux/moduleparam.h> /* For new moduleparam's */
	56	#include <linux/types.h> /* For standard types (like size_t) */
	57	#include <linux/errno.h> /* For the -ENODEV/... values */
	58	#include <linux/kernel.h> /* For printk/panic/... */
487722cf	59	#include <linux/miscdevice.h> /* For struct miscdevice */
76c11f04 WVS	60	#include <linux/watchdog.h> /* For the watchdog specific items */
	61	#include <linux/fs.h> /* For file operations */
	62	#include <linux/ioport.h> /* For io-port access */
ad5fe323	63	#include <linux/platform_device.h> /* For platform_driver framework */
76c11f04	64	#include <linux/init.h> /* For __init/__exit/... */
94da1e2e AC	65	#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
94da1e2e AC	66	#include <linux/io.h> /* For inb/outb/... */
76c11f04 WVS	67
	68	/* Module information */
	69	#define DRV_NAME "acquirewdt"
1da177e4	70	#define WATCHDOG_NAME "Acquire WDT"
94da1e2e AC	71	/* There is no way to see what the correct time-out period is */
94da1e2e AC	72	#define WATCHDOG_HEARTBEAT 0
1da177e4	73
76c11f04	74	/* internal variables */
94da1e2e AC	75	/* the watchdog platform device */
94da1e2e AC	76	static struct platform_device *acq_platform_device;
1da177e4 LT	77	static unsigned long acq_is_open;
	78	static char expect_close;
	79
76c11f04	80	/* module parameters */
94da1e2e AC	81	/* You must set this - there is no sane way to probe for this board. */
94da1e2e AC	82	static int wdt_stop = 0x43;
1da177e4 LT	83	module_param(wdt_stop, int, 0);
	84	MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");
	85
94da1e2e AC	86	/* You must set this - there is no sane way to probe for this board. */
94da1e2e AC	87	static int wdt_start = 0x443;
1da177e4 LT	88	module_param(wdt_start, int, 0);
	89	MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");
	90
86a1e189 WVS	91	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	92	module_param(nowayout, bool, 0);
94da1e2e AC	93	MODULE_PARM_DESC(nowayout,
	94	"Watchdog cannot be stopped once started (default="
	95	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4 LT	96
1da177e4 LT	97	/*
76c11f04	98	* Watchdog Operations
1da177e4 LT	99	*/
	100
	101	static void acq_keepalive(void)
	102	{
	103	/* Write a watchdog value */
	104	inb_p(wdt_start);
	105	}
	106
	107	static void acq_stop(void)
	108	{
	109	/* Turn the card off */
	110	inb_p(wdt_stop);
	111	}
	112
	113	/*
76c11f04	114	* /dev/watchdog handling
1da177e4 LT	115	*/
1da177e4 LT	116
94da1e2e AC	117	static ssize_t acq_write(struct file file, const char __user buf,
94da1e2e AC	118	size_t count, loff_t *ppos)
1da177e4 LT	119	{
1da177e4 LT	120	/* See if we got the magic character 'V' and reload the timer */
94da1e2e	121	if (count) {
1da177e4 LT	122	if (!nowayout) {
1da177e4 LT	123	size_t i;
1da177e4	124	/* note: just in case someone wrote the magic character
7944d3a5	125	five months ago... */
1da177e4	126	expect_close = 0;
94da1e2e AC	127	/* scan to see whether or not we got the
94da1e2e AC	128	magic character */
1da177e4 LT	129	for (i = 0; i != count; i++) {
	130	char c;
	131	if (get_user(c, buf + i))
	132	return -EFAULT;
	133	if (c == 'V')
	134	expect_close = 42;
	135	}
	136	}
94da1e2e AC	137	/* Well, anyhow someone wrote to us, we should
94da1e2e AC	138	return that favour */
1da177e4 LT	139	acq_keepalive();
	140	}
	141	return count;
	142	}
	143
94da1e2e	144	static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 LT	145	{
	146	int options, retval = -EINVAL;
	147	void __user argp = (void __user )arg;
	148	int __user *p = argp;
42747d71	149	static const struct watchdog_info ident = {
1da177e4 LT	150	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
1da177e4 LT	151	.firmware_version = 1,
76c11f04	152	.identity = WATCHDOG_NAME,
1da177e4 LT	153	};
1da177e4 LT	154
94da1e2e	155	switch (cmd) {
1da177e4	156	case WDIOC_GETSUPPORT:
94da1e2e	157	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
1da177e4 LT	158
	159	case WDIOC_GETSTATUS:
	160	case WDIOC_GETBOOTSTATUS:
94da1e2e	161	return put_user(0, p);
1da177e4	162
1da177e4 LT	163	case WDIOC_SETOPTIONS:
1da177e4 LT	164	{
94da1e2e AC	165	if (get_user(options, p))
	166	return -EFAULT;
	167	if (options & WDIOS_DISABLECARD) {
	168	acq_stop();
	169	retval = 0;
	170	}
	171	if (options & WDIOS_ENABLECARD) {
	172	acq_keepalive();
	173	retval = 0;
	174	}
	175	return retval;
1da177e4	176	}
0c06090c WVS	177	case WDIOC_KEEPALIVE:
	178	acq_keepalive();
	179	return 0;
	180
	181	case WDIOC_GETTIMEOUT:
	182	return put_user(WATCHDOG_HEARTBEAT, p);
	183
1da177e4	184	default:
94da1e2e	185	return -ENOTTY;
1da177e4 LT	186	}
	187	}
	188
	189	static int acq_open(struct inode inode, struct file file)
	190	{
	191	if (test_and_set_bit(0, &acq_is_open))
	192	return -EBUSY;
	193
	194	if (nowayout)
	195	__module_get(THIS_MODULE);
	196
	197	/* Activate */
	198	acq_keepalive();
c5bf68fe	199	return stream_open(inode, file);
1da177e4 LT	200	}
	201
	202	static int acq_close(struct inode inode, struct file file)
	203	{
	204	if (expect_close == 42) {
	205	acq_stop();
	206	} else {
27c766aa	207	pr_crit("Unexpected close, not stopping watchdog!\n");
1da177e4 LT	208	acq_keepalive();
	209	}
	210	clear_bit(0, &acq_is_open);
	211	expect_close = 0;
	212	return 0;
	213	}
	214
1da177e4 LT	215	/*
	216	* Kernel Interfaces
	217	*/
	218
62322d25	219	static const struct file_operations acq_fops = {
1da177e4 LT	220	.owner = THIS_MODULE,
	221	.llseek = no_llseek,
	222	.write = acq_write,
94da1e2e	223	.unlocked_ioctl = acq_ioctl,
b6dfb247	224	.compat_ioctl = compat_ptr_ioctl,
1da177e4 LT	225	.open = acq_open,
	226	.release = acq_close,
	227	};
	228
76c11f04 WVS	229	static struct miscdevice acq_miscdev = {
	230	.minor = WATCHDOG_MINOR,
	231	.name = "watchdog",
	232	.fops = &acq_fops,
1da177e4 LT	233	};
1da177e4 LT	234
76c11f04 WVS	235	/*
	236	* Init & exit routines
	237	*/
	238
b0e0b4b5	239	static int __init acq_probe(struct platform_device *dev)
1da177e4 LT	240	{
	241	int ret;
	242
1da177e4 LT	243	if (wdt_stop != wdt_start) {
1da177e4 LT	244	if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
27c766aa	245	pr_err("I/O address 0x%04x already in use\n", wdt_stop);
1da177e4 LT	246	ret = -EIO;
	247	goto out;
	248	}
	249	}
	250
	251	if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
27c766aa	252	pr_err("I/O address 0x%04x already in use\n", wdt_start);
1da177e4 LT	253	ret = -EIO;
	254	goto unreg_stop;
	255	}
1da177e4 LT	256	ret = misc_register(&acq_miscdev);
1da177e4 LT	257	if (ret != 0) {
27c766aa JP	258	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
27c766aa JP	259	WATCHDOG_MINOR, ret);
98c08e98	260	goto unreg_regions;
1da177e4	261	}
27c766aa	262	pr_info("initialized. (nowayout=%d)\n", nowayout);
1da177e4 LT	263
1da177e4 LT	264	return 0;
1da177e4 LT	265	unreg_regions:
	266	release_region(wdt_start, 1);
	267	unreg_stop:
	268	if (wdt_stop != wdt_start)
	269	release_region(wdt_stop, 1);
	270	out:
	271	return ret;
	272	}
	273
4b12b896	274	static int acq_remove(struct platform_device *dev)
1da177e4 LT	275	{
1da177e4 LT	276	misc_deregister(&acq_miscdev);
94da1e2e AC	277	release_region(wdt_start, 1);
	278	if (wdt_stop != wdt_start)
	279	release_region(wdt_stop, 1);
ad5fe323 WVS	280
	281	return 0;
	282	}
	283
98c08e98 WVS	284	static void acq_shutdown(struct platform_device *dev)
	285	{
	286	/* Turn the WDT off if we have a soft shutdown */
	287	acq_stop();
	288	}
	289
ad5fe323	290	static struct platform_driver acquirewdt_driver = {
82268714	291	.remove = acq_remove,
98c08e98	292	.shutdown = acq_shutdown,
ad5fe323	293	.driver = {
ad5fe323 WVS	294	.name = DRV_NAME,
	295	},
	296	};
	297
	298	static int __init acq_init(void)
	299	{
	300	int err;
	301
27c766aa	302	pr_info("WDT driver for Acquire single board computer initialising\n");
ad5fe323	303
94da1e2e AC	304	acq_platform_device = platform_device_register_simple(DRV_NAME,
94da1e2e AC	305	-1, NULL, 0);
b0e0b4b5 JD	306	if (IS_ERR(acq_platform_device))
	307	return PTR_ERR(acq_platform_device);
	308
	309	err = platform_driver_probe(&acquirewdt_driver, acq_probe);
	310	if (err)
	311	goto unreg_platform_device;
ad5fe323 WVS	312	return 0;
ad5fe323 WVS	313
b0e0b4b5 JD	314	unreg_platform_device:
b0e0b4b5 JD	315	platform_device_unregister(acq_platform_device);
ad5fe323 WVS	316	return err;
	317	}
	318
	319	static void __exit acq_exit(void)
	320	{
	321	platform_device_unregister(acq_platform_device);
	322	platform_driver_unregister(&acquirewdt_driver);
27c766aa	323	pr_info("Watchdog Module Unloaded\n");
1da177e4 LT	324	}
	325
	326	module_init(acq_init);
	327	module_exit(acq_exit);
	328
	329	MODULE_AUTHOR("David Woodhouse");
	330	MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
	331	MODULE_LICENSE("GPL");