[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)
1da177e4	111	printk(KERN_WARNING NAME ": watchdog device closed unexpectedly, will not disable the watchdog timer\n");
9b748ed0	112	else if (!nowayout)
1da177e4	113	scx200_wdt_disable();
1da177e4	114	expect_close = 0;
9b748ed0	115	clear_bit(0, &open_lock);
1da177e4 LT	116
	117	return 0;
	118	}
	119
	120	static int scx200_wdt_notify_sys(struct notifier_block *this,
	121	unsigned long code, void *unused)
	122	{
	123	if (code == SYS_HALT \|\| code == SYS_POWER_OFF)
	124	if (!nowayout)
	125	scx200_wdt_disable();
	126
	127	return NOTIFY_DONE;
	128	}
	129
9b748ed0	130	static struct notifier_block scx200_wdt_notifier = {
1da177e4 LT	131	.notifier_call = scx200_wdt_notify_sys,
	132	};
	133
	134	static ssize_t scx200_wdt_write(struct file file, const char __user data,
	135	size_t len, loff_t *ppos)
	136	{
	137	/* check for a magic close character */
9b748ed0	138	if (len) {
1da177e4 LT	139	size_t i;
	140
	141	scx200_wdt_ping();
	142
	143	expect_close = 0;
	144	for (i = 0; i < len; ++i) {
	145	char c;
7944d3a5	146	if (get_user(c, data + i))
1da177e4 LT	147	return -EFAULT;
	148	if (c == 'V')
	149	expect_close = 42;
	150	}
	151
	152	return len;
	153	}
	154
	155	return 0;
	156	}
	157
9b748ed0 AC	158	static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
9b748ed0 AC	159	unsigned long arg)
1da177e4 LT	160	{
	161	void __user argp = (void __user )arg;
	162	int __user *p = argp;
9b748ed0	163	static const struct watchdog_info ident = {
1da177e4 LT	164	.identity = "NatSemi SCx200 Watchdog",
1da177e4 LT	165	.firmware_version = 1,
9b748ed0	166	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
1da177e4 LT	167	};
	168	int new_margin;
	169
	170	switch (cmd) {
1da177e4	171	case WDIOC_GETSUPPORT:
9b748ed0	172	if (copy_to_user(argp, &ident, sizeof(ident)))
1da177e4 LT	173	return -EFAULT;
	174	return 0;
	175	case WDIOC_GETSTATUS:
	176	case WDIOC_GETBOOTSTATUS:
	177	if (put_user(0, p))
	178	return -EFAULT;
	179	return 0;
	180	case WDIOC_KEEPALIVE:
	181	scx200_wdt_ping();
	182	return 0;
	183	case WDIOC_SETTIMEOUT:
	184	if (get_user(new_margin, p))
	185	return -EFAULT;
	186	if (new_margin < 1)
	187	return -EINVAL;
	188	margin = new_margin;
	189	scx200_wdt_update_margin();
	190	scx200_wdt_ping();
	191	case WDIOC_GETTIMEOUT:
	192	if (put_user(margin, p))
	193	return -EFAULT;
	194	return 0;
0c06090c WVS	195	default:
0c06090c WVS	196	return -ENOTTY;
1da177e4 LT	197	}
	198	}
	199
62322d25	200	static const struct file_operations scx200_wdt_fops = {
9b748ed0 AC	201	.owner = THIS_MODULE,
	202	.llseek = no_llseek,
	203	.write = scx200_wdt_write,
	204	.unlocked_ioctl = scx200_wdt_ioctl,
	205	.open = scx200_wdt_open,
1da177e4 LT	206	.release = scx200_wdt_release,
	207	};
	208
	209	static struct miscdevice scx200_wdt_miscdev = {
	210	.minor = WATCHDOG_MINOR,
9b748ed0 AC	211	.name = "watchdog",
9b748ed0 AC	212	.fops = &scx200_wdt_fops,
1da177e4 LT	213	};
	214
	215	static int __init scx200_wdt_init(void)
	216	{
	217	int r;
	218
	219	printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
	220
	221	/* check that we have found the configuration block */
	222	if (!scx200_cb_present())
	223	return -ENODEV;
	224
	225	if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
	226	SCx200_WDT_SIZE,
	227	"NatSemi SCx200 Watchdog")) {
	228	printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
	229	return -EBUSY;
	230	}
	231
	232	scx200_wdt_update_margin();
	233	scx200_wdt_disable();
	234
c6cb13ae	235	r = register_reboot_notifier(&scx200_wdt_notifier);
1da177e4	236	if (r) {
c6cb13ae	237	printk(KERN_ERR NAME ": unable to register reboot notifier");
1da177e4 LT	238	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
	239	SCx200_WDT_SIZE);
	240	return r;
	241	}
	242
c6cb13ae	243	r = misc_register(&scx200_wdt_miscdev);
1da177e4	244	if (r) {
c6cb13ae	245	unregister_reboot_notifier(&scx200_wdt_notifier);
1da177e4 LT	246	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
	247	SCx200_WDT_SIZE);
	248	return r;
	249	}
	250
	251	return 0;
	252	}
	253
	254	static void __exit scx200_wdt_cleanup(void)
	255	{
1da177e4	256	misc_deregister(&scx200_wdt_miscdev);
c6cb13ae	257	unregister_reboot_notifier(&scx200_wdt_notifier);
1da177e4 LT	258	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
	259	SCx200_WDT_SIZE);
	260	}
	261
	262	module_init(scx200_wdt_init);
	263	module_exit(scx200_wdt_cleanup);
	264
	265	/*
	266	Local variables:
9b748ed0 AC	267	compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
9b748ed0 AC	268	c-basic-offset: 8
1da177e4 LT	269	End:
1da177e4 LT	270	*/