[mirror_ubuntu-artful-kernel.git] / drivers / watchdog / sbc_epx_c3.c

/*
 *	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.
 *
 *	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.
 *
 *	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 nonseekable_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,
	.llseek		= no_llseek,
	.write		= epx_c3_write,
	.unlocked_ioctl	= epx_c3_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
eed6565f CC	1	/*
	2	* SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3
	3	* single board computer
	4	*
	5	* (c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights
	6	* Reserved.
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License
	10	* as published by the Free Software Foundation; either version
	11	* 2 of the License, or (at your option) any later version.
	12	*
29fa0586	13	* based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
eed6565f CC	14	*/
eed6565f CC	15
27c766aa JP	16	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	17
eed6565f CC	18	#include <linux/module.h>
eed6565f CC	19	#include <linux/moduleparam.h>
eed6565f CC	20	#include <linux/types.h>
	21	#include <linux/kernel.h>
	22	#include <linux/fs.h>
	23	#include <linux/mm.h>
	24	#include <linux/miscdevice.h>
	25	#include <linux/watchdog.h>
	26	#include <linux/notifier.h>
	27	#include <linux/reboot.h>
	28	#include <linux/init.h>
de6c642c	29	#include <linux/ioport.h>
f4f6f65a AC	30	#include <linux/uaccess.h>
f4f6f65a AC	31	#include <linux/io.h>
eed6565f	32
eed6565f CC	33	static int epx_c3_alive;
	34
	35	#define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */
	36
86a1e189 WVS	37	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	38	module_param(nowayout, bool, 0);
143a2e54 WVS	39	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
143a2e54 WVS	40	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
eed6565f CC	41
	42	#define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
	43	#define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */
	44
	45	static void epx_c3_start(void)
	46	{
	47	outb(1, EPXC3_WATCHDOG_CTL_REG);
	48	}
	49
	50	static void epx_c3_stop(void)
	51	{
	52
	53	outb(0, EPXC3_WATCHDOG_CTL_REG);
	54
27c766aa	55	pr_info("Stopped watchdog timer\n");
eed6565f CC	56	}
	57
	58	static void epx_c3_pet(void)
	59	{
	60	outb(1, EPXC3_WATCHDOG_PET_REG);
	61	}
	62
	63	/*
	64	* Allow only one person to hold it open
	65	*/
	66	static int epx_c3_open(struct inode inode, struct file file)
	67	{
	68	if (epx_c3_alive)
	69	return -EBUSY;
	70
	71	if (nowayout)
	72	__module_get(THIS_MODULE);
	73
	74	/* Activate timer */
	75	epx_c3_start();
	76	epx_c3_pet();
	77
	78	epx_c3_alive = 1;
27c766aa	79	pr_info("Started watchdog timer\n");
eed6565f CC	80
	81	return nonseekable_open(inode, file);
	82	}
	83
	84	static int epx_c3_release(struct inode inode, struct file file)
	85	{
	86	/* Shut off the timer.
	87	* Lock it in if it's a module and we defined ...NOWAYOUT */
	88	if (!nowayout)
	89	epx_c3_stop(); /* Turn the WDT off */
	90
	91	epx_c3_alive = 0;
	92
	93	return 0;
	94	}
	95
73a09e62	96	static ssize_t epx_c3_write(struct file file, const char __user data,
eed6565f CC	97	size_t len, loff_t *ppos)
	98	{
	99	/* Refresh the timer. */
	100	if (len)
	101	epx_c3_pet();
	102	return len;
	103	}
	104
f4f6f65a AC	105	static long epx_c3_ioctl(struct file *file, unsigned int cmd,
f4f6f65a AC	106	unsigned long arg)
eed6565f CC	107	{
eed6565f CC	108	int options, retval = -EINVAL;
73a09e62	109	int __user argp = (void __user )arg;
f4f6f65a	110	static const struct watchdog_info ident = {
e73a7802	111	.options = WDIOF_KEEPALIVEPING,
eed6565f CC	112	.firmware_version = 0,
	113	.identity = "Winsystems EPX-C3 H/W Watchdog",
	114	};
	115
	116	switch (cmd) {
	117	case WDIOC_GETSUPPORT:
73a09e62	118	if (copy_to_user(argp, &ident, sizeof(ident)))
eed6565f CC	119	return -EFAULT;
	120	return 0;
	121	case WDIOC_GETSTATUS:
	122	case WDIOC_GETBOOTSTATUS:
73a09e62	123	return put_user(0, argp);
73a09e62 AV	124	case WDIOC_SETOPTIONS:
73a09e62 AV	125	if (get_user(options, argp))
eed6565f CC	126	return -EFAULT;
	127
	128	if (options & WDIOS_DISABLECARD) {
	129	epx_c3_stop();
	130	retval = 0;
	131	}
	132
	133	if (options & WDIOS_ENABLECARD) {
	134	epx_c3_start();
	135	retval = 0;
	136	}
	137
	138	return retval;
0c06090c WVS	139	case WDIOC_KEEPALIVE:
	140	epx_c3_pet();
	141	return 0;
	142	case WDIOC_GETTIMEOUT:
	143	return put_user(WATCHDOG_TIMEOUT, argp);
eed6565f	144	default:
795b89d2	145	return -ENOTTY;
eed6565f CC	146	}
	147	}
	148
	149	static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code,
	150	void *unused)
	151	{
	152	if (code == SYS_DOWN \|\| code == SYS_HALT)
	153	epx_c3_stop(); /* Turn the WDT off */
	154
	155	return NOTIFY_DONE;
	156	}
	157
62322d25	158	static const struct file_operations epx_c3_fops = {
eed6565f CC	159	.owner = THIS_MODULE,
	160	.llseek = no_llseek,
	161	.write = epx_c3_write,
f4f6f65a	162	.unlocked_ioctl = epx_c3_ioctl,
eed6565f CC	163	.open = epx_c3_open,
	164	.release = epx_c3_release,
	165	};
	166
	167	static struct miscdevice epx_c3_miscdev = {
	168	.minor = WATCHDOG_MINOR,
	169	.name = "watchdog",
	170	.fops = &epx_c3_fops,
	171	};
	172
	173	static struct notifier_block epx_c3_notifier = {
	174	.notifier_call = epx_c3_notify_sys,
	175	};
	176
eed6565f CC	177	static int __init watchdog_init(void)
	178	{
	179	int ret;
	180
de6c642c AC	181	if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
	182	return -EBUSY;
	183
eed6565f CC	184	ret = register_reboot_notifier(&epx_c3_notifier);
eed6565f CC	185	if (ret) {
27c766aa	186	pr_err("cannot register reboot notifier (err=%d)\n", ret);
de6c642c	187	goto out;
eed6565f CC	188	}
	189
	190	ret = misc_register(&epx_c3_miscdev);
	191	if (ret) {
27c766aa JP	192	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
27c766aa JP	193	WATCHDOG_MINOR, ret);
eed6565f	194	unregister_reboot_notifier(&epx_c3_notifier);
de6c642c	195	goto out;
eed6565f CC	196	}
eed6565f CC	197
27c766aa	198	pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n");
eed6565f CC	199
eed6565f CC	200	return 0;
de6c642c AC	201
	202	out:
	203	release_region(EPXC3_WATCHDOG_CTL_REG, 2);
	204	return ret;
eed6565f CC	205	}
	206
	207	static void __exit watchdog_exit(void)
	208	{
	209	misc_deregister(&epx_c3_miscdev);
	210	unregister_reboot_notifier(&epx_c3_notifier);
de6c642c	211	release_region(EPXC3_WATCHDOG_CTL_REG, 2);
eed6565f CC	212	}
	213
	214	module_init(watchdog_init);
	215	module_exit(watchdog_exit);
	216
	217	MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
a77dba7e WVS	218	MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. "
a77dba7e WVS	219	"Note that there is no way to probe for this device -- "
ae0e47f0	220	"so only use it if you are sure you are running on this specific "
a77dba7e	221	"SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!");
eed6565f	222	MODULE_LICENSE("GPL");