[net-next-2.6.git] / drivers / watchdog / scx200_wdt.c

/* drivers/char/watchdog/scx200_wdt.c

   National Semiconductor SCx200 Watchdog support

   Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>

   Some code taken from:
   National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
   (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>

   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.

   The author(s) of this software shall not be held liable for damages
   of any nature resulting due to the use of this software. This
   software is provided AS-IS with no warranties. */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/scx200.h>
#include <linux/uaccess.h>
#include <linux/io.h>

#define NAME "scx200_wdt"

MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

static int margin = 60;		/* in seconds */
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds");

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");

static u16 wdto_restart;
static char expect_close;
static unsigned long open_lock;
static DEFINE_SPINLOCK(scx_lock);

/* Bits of the WDCNFG register */
#define W_ENABLE 0x00fa		/* Enable watchdog */
#define W_DISABLE 0x0000	/* Disable watchdog */

/* The scaling factor for the timer, this depends on the value of W_ENABLE */
#define W_SCALE (32768/1024)

static void scx200_wdt_ping(void)
{
	spin_lock(&scx_lock);
	outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
	spin_unlock(&scx_lock);
}

static void scx200_wdt_update_margin(void)
{
	printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
	wdto_restart = margin * W_SCALE;
}

static void scx200_wdt_enable(void)
{
	printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n",
	       wdto_restart);

	spin_lock(&scx_lock);
	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
	outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
	spin_unlock(&scx_lock);

	scx200_wdt_ping();
}

static void scx200_wdt_disable(void)
{
	printk(KERN_DEBUG NAME ": disabling watchdog timer\n");

	spin_lock(&scx_lock);
	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
	outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
	spin_unlock(&scx_lock);
}

static int scx200_wdt_open(struct inode *inode, struct file *file)
{
	/* only allow one at a time */
	if (test_and_set_bit(0, &open_lock))
		return -EBUSY;
	scx200_wdt_enable();

	return nonseekable_open(inode, file);
}

static int scx200_wdt_release(struct inode *inode, struct file *file)
{
	if (expect_close != 42)
		printk(KERN_WARNING NAME
			": watchdog device closed unexpectedly, "
			"will not disable the watchdog timer\n");
	else if (!nowayout)
		scx200_wdt_disable();
	expect_close = 0;
	clear_bit(0, &open_lock);

	return 0;
}

static int scx200_wdt_notify_sys(struct notifier_block *this,
				      unsigned long code, void *unused)
{
	if (code == SYS_HALT || code == SYS_POWER_OFF)
		if (!nowayout)
			scx200_wdt_disable();

	return NOTIFY_DONE;
}

static struct notifier_block scx200_wdt_notifier = {
	.notifier_call = scx200_wdt_notify_sys,
};

static ssize_t scx200_wdt_write(struct file *file, const char __user *data,
				     size_t len, loff_t *ppos)
{
	/* check for a magic close character */
	if (len) {
		size_t i;

		scx200_wdt_ping();

		expect_close = 0;
		for (i = 0; i < len; ++i) {
			char c;
			if (get_user(c, data + i))
				return -EFAULT;
			if (c == 'V')
				expect_close = 42;
		}

		return len;
	}

	return 0;
}

static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
		.identity = "NatSemi SCx200 Watchdog",
		.firmware_version = 1,
		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
	};
	int new_margin;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &ident, sizeof(ident)))
			return -EFAULT;
		return 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		if (put_user(0, p))
			return -EFAULT;
		return 0;
	case WDIOC_KEEPALIVE:
		scx200_wdt_ping();
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_margin, p))
			return -EFAULT;
		if (new_margin < 1)
			return -EINVAL;
		margin = new_margin;
		scx200_wdt_update_margin();
		scx200_wdt_ping();
	case WDIOC_GETTIMEOUT:
		if (put_user(margin, p))
			return -EFAULT;
		return 0;
	default:
		return -ENOTTY;
	}
}

static const struct file_operations scx200_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = scx200_wdt_write,
	.unlocked_ioctl = scx200_wdt_ioctl,
	.open = scx200_wdt_open,
	.release = scx200_wdt_release,
};

static struct miscdevice scx200_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &scx200_wdt_fops,
};

static int __init scx200_wdt_init(void)
{
	int r;

	printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");

	/* check that we have found the configuration block */
	if (!scx200_cb_present())
		return -ENODEV;

	if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
			    SCx200_WDT_SIZE,
			    "NatSemi SCx200 Watchdog")) {
		printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
		return -EBUSY;
	}

	scx200_wdt_update_margin();
	scx200_wdt_disable();

	r = register_reboot_notifier(&scx200_wdt_notifier);
	if (r) {
		printk(KERN_ERR NAME ": unable to register reboot notifier");
		release_region(scx200_cb_base + SCx200_WDT_OFFSET,
				SCx200_WDT_SIZE);
		return r;
	}

	r = misc_register(&scx200_wdt_miscdev);
	if (r) {
		unregister_reboot_notifier(&scx200_wdt_notifier);
		release_region(scx200_cb_base + SCx200_WDT_OFFSET,
				SCx200_WDT_SIZE);
		return r;
	}

	return 0;
}

static void __exit scx200_wdt_cleanup(void)
{
	misc_deregister(&scx200_wdt_miscdev);
	unregister_reboot_notifier(&scx200_wdt_notifier);
	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
		       SCx200_WDT_SIZE);
}

module_init(scx200_wdt_init);
module_exit(scx200_wdt_cleanup);

/*
    Local variables:
	compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
	c-basic-offset: 8
    End:
*/
Commit	Line	Data
1da177e4 LT	1	/* drivers/char/watchdog/scx200_wdt.c
	2
	3	National Semiconductor SCx200 Watchdog support
	4
	5	Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
	6
	7	Some code taken from:
	8	National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
	9	(c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>
	10
	11	This program is free software; you can redistribute it and/or
	12	modify it under the terms of the GNU General Public License as
	13	published by the Free Software Foundation; either version 2 of the
	14	License, or (at your option) any later version.
	15
	16	The author(s) of this software shall not be held liable for damages
	17	of any nature resulting due to the use of this software. This
	18	software is provided AS-IS with no warranties. */
	19
1da177e4 LT	20	#include <linux/module.h>
	21	#include <linux/moduleparam.h>
	22	#include <linux/init.h>
	23	#include <linux/miscdevice.h>
	24	#include <linux/watchdog.h>
	25	#include <linux/notifier.h>
	26	#include <linux/reboot.h>
	27	#include <linux/fs.h>
6473d160	28	#include <linux/ioport.h>
1da177e4	29	#include <linux/scx200.h>
9b748ed0 AC	30	#include <linux/uaccess.h>
9b748ed0 AC	31	#include <linux/io.h>
1da177e4 LT	32
	33	#define NAME "scx200_wdt"
	34
	35	MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
	36	MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
	37	MODULE_LICENSE("GPL");
	38	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	39
1da177e4 LT	40	static int margin = 60; /* in seconds */
	41	module_param(margin, int, 0);
	42	MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
	43
4bfdf378	44	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4 LT	45	module_param(nowayout, int, 0);
	46	MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
	47
	48	static u16 wdto_restart;
1da177e4	49	static char expect_close;
9b748ed0 AC	50	static unsigned long open_lock;
9b748ed0 AC	51	static DEFINE_SPINLOCK(scx_lock);
1da177e4 LT	52
	53	/* Bits of the WDCNFG register */
	54	#define W_ENABLE 0x00fa /* Enable watchdog */
	55	#define W_DISABLE 0x0000 /* Disable watchdog */
	56
	57	/* The scaling factor for the timer, this depends on the value of W_ENABLE */
	58	#define W_SCALE (32768/1024)
	59
	60	static void scx200_wdt_ping(void)
	61	{
9b748ed0	62	spin_lock(&scx_lock);
1da177e4	63	outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
9b748ed0	64	spin_unlock(&scx_lock);
1da177e4 LT	65	}
	66
	67	static void scx200_wdt_update_margin(void)
	68	{
	69	printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
	70	wdto_restart = margin * W_SCALE;
	71	}
	72
	73	static void scx200_wdt_enable(void)
	74	{
	75	printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n",
	76	wdto_restart);
	77
9b748ed0	78	spin_lock(&scx_lock);
1da177e4 LT	79	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
	80	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
	81	outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
9b748ed0	82	spin_unlock(&scx_lock);
1da177e4 LT	83
	84	scx200_wdt_ping();
	85	}
	86
	87	static void scx200_wdt_disable(void)
	88	{
	89	printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
	90
9b748ed0	91	spin_lock(&scx_lock);
1da177e4 LT	92	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
	93	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
	94	outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
9b748ed0	95	spin_unlock(&scx_lock);
1da177e4 LT	96	}
	97
	98	static int scx200_wdt_open(struct inode inode, struct file file)
	99	{
	100	/* only allow one at a time */
9b748ed0	101	if (test_and_set_bit(0, &open_lock))
1da177e4 LT	102	return -EBUSY;
	103	scx200_wdt_enable();
	104
	105	return nonseekable_open(inode, file);
	106	}
	107
	108	static int scx200_wdt_release(struct inode inode, struct file file)
	109	{
9b748ed0	110	if (expect_close != 42)
a77dba7e WVS	111	printk(KERN_WARNING NAME
	112	": watchdog device closed unexpectedly, "
	113	"will not disable the watchdog timer\n");
9b748ed0	114	else if (!nowayout)
1da177e4	115	scx200_wdt_disable();
1da177e4	116	expect_close = 0;
9b748ed0	117	clear_bit(0, &open_lock);
1da177e4 LT	118
	119	return 0;
	120	}
	121
	122	static int scx200_wdt_notify_sys(struct notifier_block *this,
	123	unsigned long code, void *unused)
	124	{
	125	if (code == SYS_HALT \|\| code == SYS_POWER_OFF)
	126	if (!nowayout)
	127	scx200_wdt_disable();
	128
	129	return NOTIFY_DONE;
	130	}
	131
9b748ed0	132	static struct notifier_block scx200_wdt_notifier = {
1da177e4 LT	133	.notifier_call = scx200_wdt_notify_sys,
	134	};
	135
	136	static ssize_t scx200_wdt_write(struct file file, const char __user data,
	137	size_t len, loff_t *ppos)
	138	{
	139	/* check for a magic close character */
9b748ed0	140	if (len) {
1da177e4 LT	141	size_t i;
	142
	143	scx200_wdt_ping();
	144
	145	expect_close = 0;
	146	for (i = 0; i < len; ++i) {
	147	char c;
7944d3a5	148	if (get_user(c, data + i))
1da177e4 LT	149	return -EFAULT;
	150	if (c == 'V')
	151	expect_close = 42;
	152	}
	153
	154	return len;
	155	}
	156
	157	return 0;
	158	}
	159
9b748ed0 AC	160	static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
9b748ed0 AC	161	unsigned long arg)
1da177e4 LT	162	{
	163	void __user argp = (void __user )arg;
	164	int __user *p = argp;
9b748ed0	165	static const struct watchdog_info ident = {
1da177e4 LT	166	.identity = "NatSemi SCx200 Watchdog",
1da177e4 LT	167	.firmware_version = 1,
9b748ed0	168	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
1da177e4 LT	169	};
	170	int new_margin;
	171
	172	switch (cmd) {
1da177e4	173	case WDIOC_GETSUPPORT:
9b748ed0	174	if (copy_to_user(argp, &ident, sizeof(ident)))
1da177e4 LT	175	return -EFAULT;
	176	return 0;
	177	case WDIOC_GETSTATUS:
	178	case WDIOC_GETBOOTSTATUS:
	179	if (put_user(0, p))
	180	return -EFAULT;
	181	return 0;
	182	case WDIOC_KEEPALIVE:
	183	scx200_wdt_ping();
	184	return 0;
	185	case WDIOC_SETTIMEOUT:
	186	if (get_user(new_margin, p))
	187	return -EFAULT;
	188	if (new_margin < 1)
	189	return -EINVAL;
	190	margin = new_margin;
	191	scx200_wdt_update_margin();
	192	scx200_wdt_ping();
	193	case WDIOC_GETTIMEOUT:
	194	if (put_user(margin, p))
	195	return -EFAULT;
	196	return 0;
0c06090c WVS	197	default:
0c06090c WVS	198	return -ENOTTY;
1da177e4 LT	199	}
	200	}
	201
62322d25	202	static const struct file_operations scx200_wdt_fops = {
9b748ed0 AC	203	.owner = THIS_MODULE,
	204	.llseek = no_llseek,
	205	.write = scx200_wdt_write,
	206	.unlocked_ioctl = scx200_wdt_ioctl,
	207	.open = scx200_wdt_open,
1da177e4 LT	208	.release = scx200_wdt_release,
	209	};
	210
	211	static struct miscdevice scx200_wdt_miscdev = {
	212	.minor = WATCHDOG_MINOR,
9b748ed0 AC	213	.name = "watchdog",
9b748ed0 AC	214	.fops = &scx200_wdt_fops,
1da177e4 LT	215	};
	216
	217	static int __init scx200_wdt_init(void)
	218	{
	219	int r;
	220
	221	printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
	222
	223	/* check that we have found the configuration block */
	224	if (!scx200_cb_present())
	225	return -ENODEV;
	226
	227	if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
	228	SCx200_WDT_SIZE,
	229	"NatSemi SCx200 Watchdog")) {
	230	printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
	231	return -EBUSY;
	232	}
	233
	234	scx200_wdt_update_margin();
	235	scx200_wdt_disable();
	236
c6cb13ae	237	r = register_reboot_notifier(&scx200_wdt_notifier);
1da177e4	238	if (r) {
c6cb13ae	239	printk(KERN_ERR NAME ": unable to register reboot notifier");
1da177e4 LT	240	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
	241	SCx200_WDT_SIZE);
	242	return r;
	243	}
	244
c6cb13ae	245	r = misc_register(&scx200_wdt_miscdev);
1da177e4	246	if (r) {
c6cb13ae	247	unregister_reboot_notifier(&scx200_wdt_notifier);
1da177e4 LT	248	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
	249	SCx200_WDT_SIZE);
	250	return r;
	251	}
	252
	253	return 0;
	254	}
	255
	256	static void __exit scx200_wdt_cleanup(void)
	257	{
1da177e4	258	misc_deregister(&scx200_wdt_miscdev);
c6cb13ae	259	unregister_reboot_notifier(&scx200_wdt_notifier);
1da177e4 LT	260	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
	261	SCx200_WDT_SIZE);
	262	}
	263
	264	module_init(scx200_wdt_init);
	265	module_exit(scx200_wdt_cleanup);
	266
	267	/*
	268	Local variables:
9b748ed0 AC	269	compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
9b748ed0 AC	270	c-basic-offset: 8
1da177e4 LT	271	End:
1da177e4 LT	272	*/