[deliverable/linux.git] / drivers / char / 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/config.h>
#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/pci.h>
#include <linux/scx200.h>

#include <asm/uaccess.h>
#include <asm/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 struct semaphore open_semaphore;
static char expect_close;

/* 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)
{
	outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
}

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);

	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);

	scx200_wdt_ping();
}

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

	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);
}

static int scx200_wdt_open(struct inode *inode, struct file *file)
{
	/* only allow one at a time */
	if (down_trylock(&open_semaphore))
		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;
	up(&open_semaphore);

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

	switch (cmd) {
	default:
		return -ENOIOCTLCMD;
	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;
	}
}

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

static struct miscdevice scx200_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name  = NAME,
	.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();

	sema_init(&open_semaphore, 1);

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

	r = register_reboot_notifier(&scx200_wdt_notifier);
	if (r) {
		printk(KERN_ERR NAME ": unable to register reboot notifier");
		misc_deregister(&scx200_wdt_miscdev);
		release_region(scx200_cb_base + SCx200_WDT_OFFSET,
				SCx200_WDT_SIZE);
		return r;
	}

	return 0;
}

static void __exit scx200_wdt_cleanup(void)
{
	unregister_reboot_notifier(&scx200_wdt_notifier);
	misc_deregister(&scx200_wdt_miscdev);
	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
	20	#include <linux/config.h>
	21	#include <linux/module.h>
	22	#include <linux/moduleparam.h>
	23	#include <linux/init.h>
	24	#include <linux/miscdevice.h>
	25	#include <linux/watchdog.h>
	26	#include <linux/notifier.h>
	27	#include <linux/reboot.h>
	28	#include <linux/fs.h>
	29	#include <linux/pci.h>
	30	#include <linux/scx200.h>
	31
	32	#include <asm/uaccess.h>
	33	#include <asm/io.h>
	34
	35	#define NAME "scx200_wdt"
	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
4bfdf378	46	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4 LT	47	module_param(nowayout, int, 0);
	48	MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
	49
	50	static u16 wdto_restart;
	51	static struct semaphore open_semaphore;
	52	static char expect_close;
	53
	54	/* Bits of the WDCNFG register */
	55	#define W_ENABLE 0x00fa /* Enable watchdog */
	56	#define W_DISABLE 0x0000 /* Disable watchdog */
	57
	58	/* The scaling factor for the timer, this depends on the value of W_ENABLE */
	59	#define W_SCALE (32768/1024)
	60
	61	static void scx200_wdt_ping(void)
	62	{
	63	outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
	64	}
	65
	66	static void scx200_wdt_update_margin(void)
	67	{
	68	printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
	69	wdto_restart = margin * W_SCALE;
	70	}
	71
	72	static void scx200_wdt_enable(void)
	73	{
	74	printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n",
	75	wdto_restart);
	76
	77	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
	78	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
	79	outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
	80
	81	scx200_wdt_ping();
	82	}
	83
	84	static void scx200_wdt_disable(void)
	85	{
	86	printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
	87
	88	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
	89	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
	90	outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
	91	}
	92
	93	static int scx200_wdt_open(struct inode inode, struct file file)
	94	{
	95	/* only allow one at a time */
	96	if (down_trylock(&open_semaphore))
	97	return -EBUSY;
	98	scx200_wdt_enable();
	99
	100	return nonseekable_open(inode, file);
	101	}
	102
	103	static int scx200_wdt_release(struct inode inode, struct file file)
	104	{
	105	if (expect_close != 42) {
	106	printk(KERN_WARNING NAME ": watchdog device closed unexpectedly, will not disable the watchdog timer\n");
	107	} else if (!nowayout) {
	108	scx200_wdt_disable();
	109	}
	110	expect_close = 0;
111	up(&open_semaphore);
112
113	return 0;
114	}
115
116	static int scx200_wdt_notify_sys(struct notifier_block *this,
117	unsigned long code, void *unused)
118	{
119	if (code == SYS_HALT \|\| code == SYS_POWER_OFF)
120	if (!nowayout)
121	scx200_wdt_disable();
122
123	return NOTIFY_DONE;
124	}
125
126	static struct notifier_block scx200_wdt_notifier =
127	{
128	.notifier_call = scx200_wdt_notify_sys,
129	};
130
131	static ssize_t scx200_wdt_write(struct file file, const char __user data,
132	size_t len, loff_t *ppos)
133	{
134	/* check for a magic close character */
135	if (len)
136	{
137	size_t i;
138
139	scx200_wdt_ping();
140
141	expect_close = 0;
142	for (i = 0; i < len; ++i) {
143	char c;
144	if (get_user(c, data+i))
145	return -EFAULT;
146	if (c == 'V')
147	expect_close = 42;
148	}
149
150	return len;
151	}
152
153	return 0;
154	}
155
156	static int scx200_wdt_ioctl(struct inode inode, struct file file,
157	unsigned int cmd, unsigned long arg)
158	{
159	void __user argp = (void __user )arg;
160	int __user *p = argp;
161	static struct watchdog_info ident = {
162	.identity = "NatSemi SCx200 Watchdog",
163	.firmware_version = 1,
164	.options = (WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING),
165	};
166	int new_margin;
167
168	switch (cmd) {
169	default:
170	return -ENOIOCTLCMD;
171	case WDIOC_GETSUPPORT:
172	if(copy_to_user(argp, &ident, sizeof(ident)))
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;
195	}
196	}
197
198	static struct file_operations scx200_wdt_fops = {
199	.owner = THIS_MODULE,
200	.llseek = no_llseek,
201	.write = scx200_wdt_write,
202	.ioctl = scx200_wdt_ioctl,
203	.open = scx200_wdt_open,
204	.release = scx200_wdt_release,
205	};
206
207	static struct miscdevice scx200_wdt_miscdev = {
208	.minor = WATCHDOG_MINOR,
209	.name = NAME,
210	.fops = &scx200_wdt_fops,
211	};
212
213	static int __init scx200_wdt_init(void)
214	{
215	int r;
216
217	printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
218
219	/* check that we have found the configuration block */
220	if (!scx200_cb_present())
221	return -ENODEV;
222
223	if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
224	SCx200_WDT_SIZE,
225	"NatSemi SCx200 Watchdog")) {
226	printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
227	return -EBUSY;
228	}
229
230	scx200_wdt_update_margin();
231	scx200_wdt_disable();
232
233	sema_init(&open_semaphore, 1);
234
235	r = misc_register(&scx200_wdt_miscdev);
236	if (r) {
237	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
238	SCx200_WDT_SIZE);
239	return r;
240	}
241
242	r = register_reboot_notifier(&scx200_wdt_notifier);
243	if (r) {
244	printk(KERN_ERR NAME ": unable to register reboot notifier");
245	misc_deregister(&scx200_wdt_miscdev);
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	{
256	unregister_reboot_notifier(&scx200_wdt_notifier);
257	misc_deregister(&scx200_wdt_miscdev);
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:
267	compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
268	c-basic-offset: 8
269	End:
270	*/