[linux-2.6-block.git] / drivers / watchdog / sbc_epx_c3.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	SBC EPX C3 0.1	A Hardware Watchdog Device for the Winsystems EPX-C3
 *	single board computer
 *
 *	(c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights
 *	Reserved.
 *
 *	based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/uaccess.h>
#include <linux/io.h>

static int epx_c3_alive;

#define WATCHDOG_TIMEOUT 1		/* 1 sec default timeout */

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) ")");

#define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
#define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */

static void epx_c3_start(void)
{
	outb(1, EPXC3_WATCHDOG_CTL_REG);
}

static void epx_c3_stop(void)
{

	outb(0, EPXC3_WATCHDOG_CTL_REG);

	pr_info("Stopped watchdog timer\n");
}

static void epx_c3_pet(void)
{
	outb(1, EPXC3_WATCHDOG_PET_REG);
}

/*
 *	Allow only one person to hold it open
 */
static int epx_c3_open(struct inode *inode, struct file *file)
{
	if (epx_c3_alive)
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	/* Activate timer */
	epx_c3_start();
	epx_c3_pet();

	epx_c3_alive = 1;
	pr_info("Started watchdog timer\n");

	return stream_open(inode, file);
}

static int epx_c3_release(struct inode *inode, struct file *file)
{
	/* Shut off the timer.
	 * Lock it in if it's a module and we defined ...NOWAYOUT */
	if (!nowayout)
		epx_c3_stop();		/* Turn the WDT off */

	epx_c3_alive = 0;

	return 0;
}

static ssize_t epx_c3_write(struct file *file, const char __user *data,
			size_t len, loff_t *ppos)
{
	/* Refresh the timer. */
	if (len)
		epx_c3_pet();
	return len;
}

static long epx_c3_ioctl(struct file *file, unsigned int cmd,
						unsigned long arg)
{
	int options, retval = -EINVAL;
	int __user *argp = (void __user *)arg;
	static const struct watchdog_info ident = {
		.options		= WDIOF_KEEPALIVEPING,
		.firmware_version	= 0,
		.identity		= "Winsystems EPX-C3 H/W Watchdog",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &ident, sizeof(ident)))
			return -EFAULT;
		return 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, argp);
	case WDIOC_SETOPTIONS:
		if (get_user(options, argp))
			return -EFAULT;

		if (options & WDIOS_DISABLECARD) {
			epx_c3_stop();
			retval = 0;
		}

		if (options & WDIOS_ENABLECARD) {
			epx_c3_start();
			retval = 0;
		}

		return retval;
	case WDIOC_KEEPALIVE:
		epx_c3_pet();
		return 0;
	case WDIOC_GETTIMEOUT:
		return put_user(WATCHDOG_TIMEOUT, argp);
	default:
		return -ENOTTY;
	}
}

static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code,
				void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		epx_c3_stop();		/* Turn the WDT off */

	return NOTIFY_DONE;
}

static const struct file_operations epx_c3_fops = {
	.owner		= THIS_MODULE,
	.write		= epx_c3_write,
	.unlocked_ioctl	= epx_c3_ioctl,
	.compat_ioctl	= compat_ptr_ioctl,
	.open		= epx_c3_open,
	.release	= epx_c3_release,
};

static struct miscdevice epx_c3_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &epx_c3_fops,
};

static struct notifier_block epx_c3_notifier = {
	.notifier_call = epx_c3_notify_sys,
};

static int __init watchdog_init(void)
{
	int ret;

	if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
		return -EBUSY;

	ret = register_reboot_notifier(&epx_c3_notifier);
	if (ret) {
		pr_err("cannot register reboot notifier (err=%d)\n", ret);
		goto out;
	}

	ret = misc_register(&epx_c3_miscdev);
	if (ret) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       WATCHDOG_MINOR, ret);
		unregister_reboot_notifier(&epx_c3_notifier);
		goto out;
	}

	pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n");

	return 0;

out:
	release_region(EPXC3_WATCHDOG_CTL_REG, 2);
	return ret;
}

static void __exit watchdog_exit(void)
{
	misc_deregister(&epx_c3_miscdev);
	unregister_reboot_notifier(&epx_c3_notifier);
	release_region(EPXC3_WATCHDOG_CTL_REG, 2);
}

module_init(watchdog_init);
module_exit(watchdog_exit);

MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC.  "
	"Note that there is no way to probe for this device -- "
	"so only use it if you are *sure* you are running on this specific "
	"SBC system from Winsystems!  It writes to IO ports 0x1ee and 0x1ef!");
MODULE_LICENSE("GPL");
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0-or-later
	2	/*
	3	* SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3
	4	* single board computer
	5	*
	6	* (c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights
	7	* Reserved.
	8	*
	9	* based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
	10	*/
	11
	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	13
	14	#include <linux/module.h>
	15	#include <linux/moduleparam.h>
	16	#include <linux/types.h>
	17	#include <linux/kernel.h>
	18	#include <linux/fs.h>
	19	#include <linux/mm.h>
	20	#include <linux/miscdevice.h>
	21	#include <linux/watchdog.h>
	22	#include <linux/notifier.h>
	23	#include <linux/reboot.h>
	24	#include <linux/init.h>
	25	#include <linux/ioport.h>
	26	#include <linux/uaccess.h>
	27	#include <linux/io.h>
	28
	29	static int epx_c3_alive;
	30
	31	#define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */
	32
	33	static bool nowayout = WATCHDOG_NOWAYOUT;
	34	module_param(nowayout, bool, 0);
	35	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	36	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	37
	38	#define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
	39	#define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */
	40
	41	static void epx_c3_start(void)
	42	{
	43	outb(1, EPXC3_WATCHDOG_CTL_REG);
	44	}
	45
	46	static void epx_c3_stop(void)
	47	{
	48
	49	outb(0, EPXC3_WATCHDOG_CTL_REG);
	50
	51	pr_info("Stopped watchdog timer\n");
	52	}
	53
	54	static void epx_c3_pet(void)
	55	{
	56	outb(1, EPXC3_WATCHDOG_PET_REG);
	57	}
	58
	59	/*
	60	* Allow only one person to hold it open
	61	*/
	62	static int epx_c3_open(struct inode inode, struct file file)
	63	{
	64	if (epx_c3_alive)
	65	return -EBUSY;
	66
	67	if (nowayout)
	68	__module_get(THIS_MODULE);
	69
	70	/* Activate timer */
	71	epx_c3_start();
	72	epx_c3_pet();
	73
	74	epx_c3_alive = 1;
	75	pr_info("Started watchdog timer\n");
	76
	77	return stream_open(inode, file);
	78	}
	79
	80	static int epx_c3_release(struct inode inode, struct file file)
	81	{
	82	/* Shut off the timer.
	83	* Lock it in if it's a module and we defined ...NOWAYOUT */
	84	if (!nowayout)
	85	epx_c3_stop(); /* Turn the WDT off */
	86
	87	epx_c3_alive = 0;
	88
	89	return 0;
	90	}
	91
	92	static ssize_t epx_c3_write(struct file file, const char __user data,
	93	size_t len, loff_t *ppos)
	94	{
	95	/* Refresh the timer. */
	96	if (len)
	97	epx_c3_pet();
	98	return len;
	99	}
	100
	101	static long epx_c3_ioctl(struct file *file, unsigned int cmd,
	102	unsigned long arg)
	103	{
	104	int options, retval = -EINVAL;
	105	int __user argp = (void __user )arg;
	106	static const struct watchdog_info ident = {
	107	.options = WDIOF_KEEPALIVEPING,
	108	.firmware_version = 0,
	109	.identity = "Winsystems EPX-C3 H/W Watchdog",
	110	};
	111
	112	switch (cmd) {
	113	case WDIOC_GETSUPPORT:
	114	if (copy_to_user(argp, &ident, sizeof(ident)))
	115	return -EFAULT;
	116	return 0;
	117	case WDIOC_GETSTATUS:
	118	case WDIOC_GETBOOTSTATUS:
	119	return put_user(0, argp);
	120	case WDIOC_SETOPTIONS:
	121	if (get_user(options, argp))
	122	return -EFAULT;
	123
	124	if (options & WDIOS_DISABLECARD) {
	125	epx_c3_stop();
	126	retval = 0;
	127	}
	128
	129	if (options & WDIOS_ENABLECARD) {
	130	epx_c3_start();
	131	retval = 0;
	132	}
	133
	134	return retval;
	135	case WDIOC_KEEPALIVE:
	136	epx_c3_pet();
	137	return 0;
	138	case WDIOC_GETTIMEOUT:
	139	return put_user(WATCHDOG_TIMEOUT, argp);
	140	default:
	141	return -ENOTTY;
	142	}
	143	}
	144
	145	static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code,
	146	void *unused)
	147	{
	148	if (code == SYS_DOWN \|\| code == SYS_HALT)
	149	epx_c3_stop(); /* Turn the WDT off */
	150
	151	return NOTIFY_DONE;
	152	}
	153
	154	static const struct file_operations epx_c3_fops = {
	155	.owner = THIS_MODULE,
	156	.write = epx_c3_write,
	157	.unlocked_ioctl = epx_c3_ioctl,
	158	.compat_ioctl = compat_ptr_ioctl,
	159	.open = epx_c3_open,
	160	.release = epx_c3_release,
	161	};
	162
	163	static struct miscdevice epx_c3_miscdev = {
	164	.minor = WATCHDOG_MINOR,
	165	.name = "watchdog",
	166	.fops = &epx_c3_fops,
	167	};
	168
	169	static struct notifier_block epx_c3_notifier = {
	170	.notifier_call = epx_c3_notify_sys,
	171	};
	172
	173	static int __init watchdog_init(void)
	174	{
	175	int ret;
	176
	177	if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
	178	return -EBUSY;
	179
	180	ret = register_reboot_notifier(&epx_c3_notifier);
	181	if (ret) {
	182	pr_err("cannot register reboot notifier (err=%d)\n", ret);
	183	goto out;
	184	}
	185
	186	ret = misc_register(&epx_c3_miscdev);
	187	if (ret) {
	188	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
	189	WATCHDOG_MINOR, ret);
	190	unregister_reboot_notifier(&epx_c3_notifier);
	191	goto out;
	192	}
	193
	194	pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n");
	195
	196	return 0;
	197
	198	out:
	199	release_region(EPXC3_WATCHDOG_CTL_REG, 2);
	200	return ret;
	201	}
	202
	203	static void __exit watchdog_exit(void)
	204	{
	205	misc_deregister(&epx_c3_miscdev);
	206	unregister_reboot_notifier(&epx_c3_notifier);
	207	release_region(EPXC3_WATCHDOG_CTL_REG, 2);
	208	}
	209
	210	module_init(watchdog_init);
	211	module_exit(watchdog_exit);
	212
	213	MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
	214	MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. "
	215	"Note that there is no way to probe for this device -- "
	216	"so only use it if you are sure you are running on this specific "
	217	"SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!");
	218	MODULE_LICENSE("GPL");