[deliverable/linux.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. */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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 DEBUG

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 bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 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)
{
	pr_info("timer margin %d seconds\n", margin);
	wdto_restart = margin * W_SCALE;
}

static void scx200_wdt_enable(void)
{
	pr_debug("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)
{
	pr_debug("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)
		pr_warn("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;

	pr_debug("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")) {
		pr_warn("watchdog I/O region busy\n");
		return -EBUSY;
	}

	scx200_wdt_update_margin();
	scx200_wdt_disable();

	r = register_reboot_notifier(&scx200_wdt_notifier);
	if (r) {
		pr_err("unable to register reboot notifier\n");
		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
27c766aa JP	20	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	21
1da177e4 LT	22	#include <linux/module.h>
	23	#include <linux/moduleparam.h>
	24	#include <linux/init.h>
	25	#include <linux/miscdevice.h>
	26	#include <linux/watchdog.h>
	27	#include <linux/notifier.h>
	28	#include <linux/reboot.h>
	29	#include <linux/fs.h>
6473d160	30	#include <linux/ioport.h>
1da177e4	31	#include <linux/scx200.h>
9b748ed0 AC	32	#include <linux/uaccess.h>
9b748ed0 AC	33	#include <linux/io.h>
1da177e4	34
27c766aa	35	#define DEBUG
1da177e4 LT	36
	37	MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
	38	MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
	39	MODULE_LICENSE("GPL");
	40	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	41
1da177e4 LT	42	static int margin = 60; /* in seconds */
	43	module_param(margin, int, 0);
	44	MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
	45
86a1e189 WVS	46	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	47	module_param(nowayout, bool, 0);
1da177e4 LT	48	MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
	49
	50	static u16 wdto_restart;
1da177e4	51	static char expect_close;
9b748ed0 AC	52	static unsigned long open_lock;
9b748ed0 AC	53	static DEFINE_SPINLOCK(scx_lock);
1da177e4 LT	54
	55	/* Bits of the WDCNFG register */
	56	#define W_ENABLE 0x00fa /* Enable watchdog */
	57	#define W_DISABLE 0x0000 /* Disable watchdog */
	58
	59	/* The scaling factor for the timer, this depends on the value of W_ENABLE */
	60	#define W_SCALE (32768/1024)
	61
	62	static void scx200_wdt_ping(void)
	63	{
9b748ed0	64	spin_lock(&scx_lock);
1da177e4	65	outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
9b748ed0	66	spin_unlock(&scx_lock);
1da177e4 LT	67	}
	68
	69	static void scx200_wdt_update_margin(void)
	70	{
27c766aa	71	pr_info("timer margin %d seconds\n", margin);
1da177e4 LT	72	wdto_restart = margin * W_SCALE;
	73	}
	74
	75	static void scx200_wdt_enable(void)
	76	{
27c766aa	77	pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart);
1da177e4	78
9b748ed0	79	spin_lock(&scx_lock);
1da177e4 LT	80	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
	81	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
	82	outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
9b748ed0	83	spin_unlock(&scx_lock);
1da177e4 LT	84
	85	scx200_wdt_ping();
	86	}
	87
	88	static void scx200_wdt_disable(void)
	89	{
27c766aa	90	pr_debug("disabling watchdog timer\n");
1da177e4	91
9b748ed0	92	spin_lock(&scx_lock);
1da177e4 LT	93	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
	94	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
	95	outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
9b748ed0	96	spin_unlock(&scx_lock);
1da177e4 LT	97	}
	98
	99	static int scx200_wdt_open(struct inode inode, struct file file)
	100	{
	101	/* only allow one at a time */
9b748ed0	102	if (test_and_set_bit(0, &open_lock))
1da177e4 LT	103	return -EBUSY;
	104	scx200_wdt_enable();
	105
	106	return nonseekable_open(inode, file);
	107	}
	108
	109	static int scx200_wdt_release(struct inode inode, struct file file)
	110	{
9b748ed0	111	if (expect_close != 42)
27c766aa	112	pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
9b748ed0	113	else if (!nowayout)
1da177e4	114	scx200_wdt_disable();
1da177e4	115	expect_close = 0;
9b748ed0	116	clear_bit(0, &open_lock);
1da177e4 LT	117
	118	return 0;
	119	}
	120
	121	static int scx200_wdt_notify_sys(struct notifier_block *this,
	122	unsigned long code, void *unused)
	123	{
	124	if (code == SYS_HALT \|\| code == SYS_POWER_OFF)
	125	if (!nowayout)
	126	scx200_wdt_disable();
	127
	128	return NOTIFY_DONE;
	129	}
	130
9b748ed0	131	static struct notifier_block scx200_wdt_notifier = {
1da177e4 LT	132	.notifier_call = scx200_wdt_notify_sys,
	133	};
	134
	135	static ssize_t scx200_wdt_write(struct file file, const char __user data,
	136	size_t len, loff_t *ppos)
	137	{
	138	/* check for a magic close character */
9b748ed0	139	if (len) {
1da177e4 LT	140	size_t i;
	141
	142	scx200_wdt_ping();
	143
	144	expect_close = 0;
	145	for (i = 0; i < len; ++i) {
	146	char c;
7944d3a5	147	if (get_user(c, data + i))
1da177e4 LT	148	return -EFAULT;
	149	if (c == 'V')
	150	expect_close = 42;
	151	}
	152
	153	return len;
	154	}
	155
	156	return 0;
	157	}
	158
9b748ed0 AC	159	static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
9b748ed0 AC	160	unsigned long arg)
1da177e4 LT	161	{
	162	void __user argp = (void __user )arg;
	163	int __user *p = argp;
9b748ed0	164	static const struct watchdog_info ident = {
1da177e4 LT	165	.identity = "NatSemi SCx200 Watchdog",
1da177e4 LT	166	.firmware_version = 1,
e73a7802 WVS	167	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
e73a7802 WVS	168	WDIOF_MAGICCLOSE,
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
27c766aa	221	pr_debug("NatSemi SCx200 Watchdog Driver\n");
1da177e4 LT	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")) {
27c766aa	230	pr_warn("watchdog I/O region busy\n");
1da177e4 LT	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) {
27c766aa	239	pr_err("unable to register reboot notifier\n");
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	*/