[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 |
						WDIOF_MAGICCLOSE,
	};
	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,
e73a7802 WVS	168	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
e73a7802 WVS	169	WDIOF_MAGICCLOSE,
1da177e4 LT	170	};
	171	int new_margin;
	172
	173	switch (cmd) {
1da177e4	174	case WDIOC_GETSUPPORT:
9b748ed0	175	if (copy_to_user(argp, &ident, sizeof(ident)))
1da177e4 LT	176	return -EFAULT;
	177	return 0;
	178	case WDIOC_GETSTATUS:
	179	case WDIOC_GETBOOTSTATUS:
	180	if (put_user(0, p))
	181	return -EFAULT;
	182	return 0;
	183	case WDIOC_KEEPALIVE:
	184	scx200_wdt_ping();
	185	return 0;
	186	case WDIOC_SETTIMEOUT:
	187	if (get_user(new_margin, p))
	188	return -EFAULT;
	189	if (new_margin < 1)
	190	return -EINVAL;
	191	margin = new_margin;
	192	scx200_wdt_update_margin();
	193	scx200_wdt_ping();
	194	case WDIOC_GETTIMEOUT:
	195	if (put_user(margin, p))
	196	return -EFAULT;
	197	return 0;
0c06090c WVS	198	default:
0c06090c WVS	199	return -ENOTTY;
1da177e4 LT	200	}
	201	}
	202
62322d25	203	static const struct file_operations scx200_wdt_fops = {
9b748ed0 AC	204	.owner = THIS_MODULE,
	205	.llseek = no_llseek,
	206	.write = scx200_wdt_write,
	207	.unlocked_ioctl = scx200_wdt_ioctl,
	208	.open = scx200_wdt_open,
1da177e4 LT	209	.release = scx200_wdt_release,
	210	};
	211
	212	static struct miscdevice scx200_wdt_miscdev = {
	213	.minor = WATCHDOG_MINOR,
9b748ed0 AC	214	.name = "watchdog",
9b748ed0 AC	215	.fops = &scx200_wdt_fops,
1da177e4 LT	216	};
	217
	218	static int __init scx200_wdt_init(void)
	219	{
	220	int r;
	221
	222	printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
	223
	224	/* check that we have found the configuration block */
	225	if (!scx200_cb_present())
	226	return -ENODEV;
	227
	228	if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
	229	SCx200_WDT_SIZE,
	230	"NatSemi SCx200 Watchdog")) {
	231	printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
	232	return -EBUSY;
	233	}
	234
	235	scx200_wdt_update_margin();
	236	scx200_wdt_disable();
	237
c6cb13ae	238	r = register_reboot_notifier(&scx200_wdt_notifier);
1da177e4	239	if (r) {
c6cb13ae	240	printk(KERN_ERR NAME ": unable to register reboot notifier");
1da177e4 LT	241	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
	242	SCx200_WDT_SIZE);
	243	return r;
	244	}
	245
c6cb13ae	246	r = misc_register(&scx200_wdt_miscdev);
1da177e4	247	if (r) {
c6cb13ae	248	unregister_reboot_notifier(&scx200_wdt_notifier);
1da177e4 LT	249	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
	250	SCx200_WDT_SIZE);
	251	return r;
	252	}
	253
	254	return 0;
	255	}
	256
	257	static void __exit scx200_wdt_cleanup(void)
	258	{
1da177e4	259	misc_deregister(&scx200_wdt_miscdev);
c6cb13ae	260	unregister_reboot_notifier(&scx200_wdt_notifier);
1da177e4 LT	261	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
	262	SCx200_WDT_SIZE);
	263	}
	264
	265	module_init(scx200_wdt_init);
	266	module_exit(scx200_wdt_cleanup);
	267
	268	/*
	269	Local variables:
9b748ed0 AC	270	compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
9b748ed0 AC	271	c-basic-offset: 8
1da177e4 LT	272	End:
1da177e4 LT	273	*/