[linux-2.6-block.git] / drivers / watchdog / ixp2000_wdt.c

/*
 * drivers/char/watchdog/ixp2000_wdt.c
 *
 * Watchdog driver for Intel IXP2000 network processors
 *
 * Adapted from the IXP4xx watchdog driver by Lennert Buytenhek.
 * The original version carries these notices:
 *
 * Author: Deepak Saxena <dsaxena@plexity.net>
 *
 * Copyright 2004 (c) MontaVista, Software, Inc.
 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <mach/hardware.h>

static int nowayout = WATCHDOG_NOWAYOUT;
static unsigned int heartbeat = 60;	/* (secs) Default is 1 minute */
static unsigned long wdt_status;
static spinlock_t wdt_lock;

#define	WDT_IN_USE		0
#define	WDT_OK_TO_CLOSE		1

static unsigned long wdt_tick_rate;

static void wdt_enable(void)
{
	spin_lock(&wdt_lock);
	ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE);
	ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
	ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
	ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE);
	spin_unlock(&wdt_lock);
}

static void wdt_disable(void)
{
	spin_lock(&wdt_lock);
	ixp2000_reg_write(IXP2000_T4_CTL, 0);
	spin_unlock(&wdt_lock);
}

static void wdt_keepalive(void)
{
	spin_lock(&wdt_lock);
	ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
	spin_unlock(&wdt_lock);
}

static int ixp2000_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
		return -EBUSY;

	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	wdt_enable();

	return nonseekable_open(inode, file);
}

static ssize_t ixp2000_wdt_write(struct file *file, const char *data,
						size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

			for (i = 0; i != len; i++) {
				char c;

				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
			}
		}
		wdt_keepalive();
	}

	return len;
}


static struct watchdog_info ident = {
	.options	= WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
				WDIOF_KEEPALIVEPING,
	.identity	= "IXP2000 Watchdog",
};

static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	int ret = -ENOTTY;
	int time;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = copy_to_user((struct watchdog_info *)arg, &ident,
				   sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
		ret = put_user(0, (int *)arg);
		break;

	case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, (int *)arg);
		break;

	case WDIOC_KEEPALIVE:
		wdt_enable();
		ret = 0;
		break;

	case WDIOC_SETTIMEOUT:
		ret = get_user(time, (int *)arg);
		if (ret)
			break;

		if (time <= 0 || time > 60) {
			ret = -EINVAL;
			break;
		}

		heartbeat = time;
		wdt_keepalive();
		/* Fall through */

	case WDIOC_GETTIMEOUT:
		ret = put_user(heartbeat, (int *)arg);
		break;
	}

	return ret;
}

static int ixp2000_wdt_release(struct inode *inode, struct file *file)
{
	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
		wdt_disable();
	else
		printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
					"timer will not stop\n");
	clear_bit(WDT_IN_USE, &wdt_status);
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	return 0;
}


static const struct file_operations ixp2000_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= ixp2000_wdt_write,
	.unlocked_ioctl	= ixp2000_wdt_ioctl,
	.open		= ixp2000_wdt_open,
	.release	= ixp2000_wdt_release,
};

static struct miscdevice ixp2000_wdt_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &ixp2000_wdt_fops,
};

static int __init ixp2000_wdt_init(void)
{
	if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
		printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n");
		return -EIO;
	}
	wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
	spin_lock_init(&wdt_lock);
	return misc_register(&ixp2000_wdt_miscdev);
}

static void __exit ixp2000_wdt_exit(void)
{
	misc_deregister(&ixp2000_wdt_miscdev);
}

module_init(ixp2000_wdt_init);
module_exit(ixp2000_wdt_exit);

MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");

module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");

module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");

MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
1da177e4	1	/*
f30c2269	2	* drivers/char/watchdog/ixp2000_wdt.c
1da177e4 LT	3	*
	4	* Watchdog driver for Intel IXP2000 network processors
	5	*
	6	* Adapted from the IXP4xx watchdog driver by Lennert Buytenhek.
	7	* The original version carries these notices:
	8	*
	9	* Author: Deepak Saxena <dsaxena@plexity.net>
	10	*
	11	* Copyright 2004 (c) MontaVista, Software, Inc.
	12	* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
	13	*
	14	* This file is licensed under the terms of the GNU General Public
	15	* License version 2. This program is licensed "as is" without any
	16	* warranty of any kind, whether express or implied.
	17	*/
	18
1da177e4 LT	19	#include <linux/module.h>
	20	#include <linux/moduleparam.h>
	21	#include <linux/types.h>
	22	#include <linux/kernel.h>
	23	#include <linux/fs.h>
	24	#include <linux/miscdevice.h>
	25	#include <linux/watchdog.h>
	26	#include <linux/init.h>
	27	#include <linux/bitops.h>
640b4f68	28	#include <linux/uaccess.h>
a09e64fb	29	#include <mach/hardware.h>
1da177e4	30
4bfdf378	31	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4 LT	32	static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */
1da177e4 LT	33	static unsigned long wdt_status;
640b4f68	34	static spinlock_t wdt_lock;
1da177e4 LT	35
	36	#define WDT_IN_USE 0
	37	#define WDT_OK_TO_CLOSE 1
	38
	39	static unsigned long wdt_tick_rate;
	40
640b4f68	41	static void wdt_enable(void)
1da177e4	42	{
640b4f68	43	spin_lock(&wdt_lock);
1da177e4 LT	44	ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) \| WDT_RESET_ENABLE);
	45	ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
	46	ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
	47	ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 \| TIMER_ENABLE);
640b4f68	48	spin_unlock(&wdt_lock);
1da177e4 LT	49	}
1da177e4 LT	50
640b4f68	51	static void wdt_disable(void)
1da177e4	52	{
640b4f68	53	spin_lock(&wdt_lock);
1da177e4	54	ixp2000_reg_write(IXP2000_T4_CTL, 0);
640b4f68	55	spin_unlock(&wdt_lock);
1da177e4 LT	56	}
1da177e4 LT	57
640b4f68	58	static void wdt_keepalive(void)
1da177e4	59	{
640b4f68	60	spin_lock(&wdt_lock);
1da177e4	61	ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
640b4f68	62	spin_unlock(&wdt_lock);
1da177e4 LT	63	}
1da177e4 LT	64
640b4f68	65	static int ixp2000_wdt_open(struct inode inode, struct file file)
1da177e4 LT	66	{
	67	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	68	return -EBUSY;
	69
	70	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	71
	72	wdt_enable();
	73
	74	return nonseekable_open(inode, file);
	75	}
	76
640b4f68 AC	77	static ssize_t ixp2000_wdt_write(struct file file, const char data,
640b4f68 AC	78	size_t len, loff_t *ppos)
1da177e4 LT	79	{
	80	if (len) {
	81	if (!nowayout) {
	82	size_t i;
	83
	84	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	85
	86	for (i = 0; i != len; i++) {
	87	char c;
	88
	89	if (get_user(c, data + i))
	90	return -EFAULT;
	91	if (c == 'V')
	92	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	93	}
	94	}
	95	wdt_keepalive();
	96	}
	97
	98	return len;
	99	}
	100
	101
	102	static struct watchdog_info ident = {
	103	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \|
	104	WDIOF_KEEPALIVEPING,
	105	.identity = "IXP2000 Watchdog",
	106	};
	107
640b4f68 AC	108	static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd,
640b4f68 AC	109	unsigned long arg)
1da177e4	110	{
795b89d2	111	int ret = -ENOTTY;
1da177e4 LT	112	int time;
	113
	114	switch (cmd) {
	115	case WDIOC_GETSUPPORT:
	116	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	117	sizeof(ident)) ? -EFAULT : 0;
	118	break;
	119
	120	case WDIOC_GETSTATUS:
	121	ret = put_user(0, (int *)arg);
	122	break;
	123
	124	case WDIOC_GETBOOTSTATUS:
	125	ret = put_user(0, (int *)arg);
	126	break;
	127
0c06090c WVS	128	case WDIOC_KEEPALIVE:
	129	wdt_enable();
	130	ret = 0;
	131	break;
	132
1da177e4 LT	133	case WDIOC_SETTIMEOUT:
	134	ret = get_user(time, (int *)arg);
	135	if (ret)
	136	break;
	137
	138	if (time <= 0 \|\| time > 60) {
	139	ret = -EINVAL;
	140	break;
	141	}
	142
	143	heartbeat = time;
	144	wdt_keepalive();
	145	/* Fall through */
	146
	147	case WDIOC_GETTIMEOUT:
	148	ret = put_user(heartbeat, (int *)arg);
	149	break;
1da177e4 LT	150	}
	151
	152	return ret;
	153	}
	154
640b4f68	155	static int ixp2000_wdt_release(struct inode inode, struct file file)
1da177e4	156	{
640b4f68	157	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
1da177e4	158	wdt_disable();
640b4f68	159	else
b36bbb6c	160	printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
1da177e4	161	"timer will not stop\n");
1da177e4 LT	162	clear_bit(WDT_IN_USE, &wdt_status);
	163	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	164
	165	return 0;
	166	}
	167
	168
640b4f68	169	static const struct file_operations ixp2000_wdt_fops = {
1da177e4 LT	170	.owner = THIS_MODULE,
	171	.llseek = no_llseek,
	172	.write = ixp2000_wdt_write,
640b4f68	173	.unlocked_ioctl = ixp2000_wdt_ioctl,
1da177e4 LT	174	.open = ixp2000_wdt_open,
	175	.release = ixp2000_wdt_release,
	176	};
	177
640b4f68	178	static struct miscdevice ixp2000_wdt_miscdev = {
1da177e4	179	.minor = WATCHDOG_MINOR,
2dab3cab	180	.name = "watchdog",
1da177e4 LT	181	.fops = &ixp2000_wdt_fops,
	182	};
	183
	184	static int __init ixp2000_wdt_init(void)
	185	{
e4fe1981 LB	186	if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
	187	printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n");
	188	return -EIO;
	189	}
e4fe1981	190	wdt_tick_rate = (IXP2000_T1_CLD HZ) / 256;
640b4f68	191	spin_lock_init(&wdt_lock);
1da177e4 LT	192	return misc_register(&ixp2000_wdt_miscdev);
	193	}
	194
	195	static void __exit ixp2000_wdt_exit(void)
	196	{
	197	misc_deregister(&ixp2000_wdt_miscdev);
	198	}
	199
	200	module_init(ixp2000_wdt_init);
	201	module_exit(ixp2000_wdt_exit);
	202
632155e6	203	MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
1da177e4 LT	204	MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
	205
	206	module_param(heartbeat, int, 0);
	207	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
	208
	209	module_param(nowayout, int, 0);
	210	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	211
	212	MODULE_LICENSE("GPL");
	213	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	214