[deliverable/linux.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>
 */

#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>

#define PFX "epx_c3: "
static int epx_c3_alive;

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

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 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);

	printk(KERN_INFO PFX "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;
	printk(KERN_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 |
					  WDIOF_MAGICCLOSE,
		.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 const char banner[] __initdata =
    KERN_INFO PFX "Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n";

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) {
		printk(KERN_ERR PFX "cannot register reboot notifier "
			"(err=%d)\n", ret);
		goto out;
	}

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

	printk(banner);

	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 runnning on this specific SBC system from Winsystems!  It writes to IO ports 0x1ee and 0x1ef!");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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	*/
	15
	16	#include <linux/module.h>
	17	#include <linux/moduleparam.h>
eed6565f CC	18	#include <linux/types.h>
	19	#include <linux/kernel.h>
	20	#include <linux/fs.h>
	21	#include <linux/mm.h>
	22	#include <linux/miscdevice.h>
	23	#include <linux/watchdog.h>
	24	#include <linux/notifier.h>
	25	#include <linux/reboot.h>
	26	#include <linux/init.h>
de6c642c	27	#include <linux/ioport.h>
f4f6f65a AC	28	#include <linux/uaccess.h>
f4f6f65a AC	29	#include <linux/io.h>
eed6565f CC	30
	31	#define PFX "epx_c3: "
	32	static int epx_c3_alive;
	33
	34	#define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */
	35
	36	static int nowayout = WATCHDOG_NOWAYOUT;
	37	module_param(nowayout, int, 0);
143a2e54 WVS	38	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
143a2e54 WVS	39	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
eed6565f CC	40
	41	#define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
	42	#define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */
	43
	44	static void epx_c3_start(void)
	45	{
	46	outb(1, EPXC3_WATCHDOG_CTL_REG);
	47	}
	48
	49	static void epx_c3_stop(void)
	50	{
	51
	52	outb(0, EPXC3_WATCHDOG_CTL_REG);
	53
	54	printk(KERN_INFO PFX "Stopped watchdog timer.\n");
	55	}
	56
	57	static void epx_c3_pet(void)
	58	{
	59	outb(1, EPXC3_WATCHDOG_PET_REG);
	60	}
	61
	62	/*
	63	* Allow only one person to hold it open
	64	*/
	65	static int epx_c3_open(struct inode inode, struct file file)
	66	{
	67	if (epx_c3_alive)
	68	return -EBUSY;
	69
	70	if (nowayout)
	71	__module_get(THIS_MODULE);
	72
	73	/* Activate timer */
	74	epx_c3_start();
	75	epx_c3_pet();
	76
	77	epx_c3_alive = 1;
	78	printk(KERN_INFO "Started watchdog timer.\n");
	79
	80	return nonseekable_open(inode, file);
	81	}
	82
	83	static int epx_c3_release(struct inode inode, struct file file)
	84	{
	85	/* Shut off the timer.
	86	* Lock it in if it's a module and we defined ...NOWAYOUT */
	87	if (!nowayout)
	88	epx_c3_stop(); /* Turn the WDT off */
	89
	90	epx_c3_alive = 0;
	91
	92	return 0;
	93	}
	94
73a09e62	95	static ssize_t epx_c3_write(struct file file, const char __user data,
eed6565f CC	96	size_t len, loff_t *ppos)
	97	{
	98	/* Refresh the timer. */
	99	if (len)
	100	epx_c3_pet();
	101	return len;
	102	}
	103
f4f6f65a AC	104	static long epx_c3_ioctl(struct file *file, unsigned int cmd,
f4f6f65a AC	105	unsigned long arg)
eed6565f CC	106	{
eed6565f CC	107	int options, retval = -EINVAL;
73a09e62	108	int __user argp = (void __user )arg;
f4f6f65a	109	static const struct watchdog_info ident = {
eed6565f CC	110	.options = WDIOF_KEEPALIVEPING \|
	111	WDIOF_MAGICCLOSE,
	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
	177	static const char banner[] __initdata =
	178	KERN_INFO PFX "Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n";
	179
	180	static int __init watchdog_init(void)
	181	{
	182	int ret;
	183
de6c642c AC	184	if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
	185	return -EBUSY;
	186
eed6565f CC	187	ret = register_reboot_notifier(&epx_c3_notifier);
	188	if (ret) {
	189	printk(KERN_ERR PFX "cannot register reboot notifier "
	190	"(err=%d)\n", ret);
de6c642c	191	goto out;
eed6565f CC	192	}
	193
	194	ret = misc_register(&epx_c3_miscdev);
	195	if (ret) {
	196	printk(KERN_ERR PFX "cannot register miscdev on minor=%d "
	197	"(err=%d)\n", WATCHDOG_MINOR, ret);
	198	unregister_reboot_notifier(&epx_c3_notifier);
de6c642c	199	goto out;
eed6565f CC	200	}
	201
	202	printk(banner);
	203
	204	return 0;
de6c642c AC	205
	206	out:
	207	release_region(EPXC3_WATCHDOG_CTL_REG, 2);
	208	return ret;
eed6565f CC	209	}
	210
	211	static void __exit watchdog_exit(void)
	212	{
	213	misc_deregister(&epx_c3_miscdev);
	214	unregister_reboot_notifier(&epx_c3_notifier);
de6c642c	215	release_region(EPXC3_WATCHDOG_CTL_REG, 2);
eed6565f CC	216	}
	217
	218	module_init(watchdog_init);
	219	module_exit(watchdog_exit);
	220
	221	MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
	222	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 runnning on this specific SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!");
	223	MODULE_LICENSE("GPL");
	224	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);