[net-next-2.6.git] / drivers / watchdog / ixp4xx_wdt.c

/*
 * drivers/char/watchdog/ixp4xx_wdt.c
 *
 * Watchdog driver for Intel IXP4xx network processors
 *
 * 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 int heartbeat = 60;	/* (secs) Default is 1 minute */
static unsigned long wdt_status;
static unsigned long boot_status;
static DEFINE_SPINLOCK(wdt_lock);

#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)

#define	WDT_IN_USE		0
#define	WDT_OK_TO_CLOSE		1

static void wdt_enable(void)
{
	spin_lock(&wdt_lock);
	*IXP4XX_OSWK = IXP4XX_WDT_KEY;
	*IXP4XX_OSWE = 0;
	*IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
	*IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
	*IXP4XX_OSWK = 0;
	spin_unlock(&wdt_lock);
}

static void wdt_disable(void)
{
	spin_lock(&wdt_lock);
	*IXP4XX_OSWK = IXP4XX_WDT_KEY;
	*IXP4XX_OSWE = 0;
	*IXP4XX_OSWK = 0;
	spin_unlock(&wdt_lock);
}

static int ixp4xx_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
ixp4xx_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_enable();
	}
	return len;
}

static const struct watchdog_info ident = {
	.options	= WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
			  WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
	.identity	= "IXP4xx Watchdog",
};


static long ixp4xx_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(boot_status, (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_enable();
		/* Fall through */

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

static int ixp4xx_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 ixp4xx_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= ixp4xx_wdt_write,
	.unlocked_ioctl	= ixp4xx_wdt_ioctl,
	.open		= ixp4xx_wdt_open,
	.release	= ixp4xx_wdt_release,
};

static struct miscdevice ixp4xx_wdt_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &ixp4xx_wdt_fops,
};

static int __init ixp4xx_wdt_init(void)
{
	int ret;

	if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
		printk(KERN_ERR "IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected"
			" - watchdog disabled\n");

		return -ENODEV;
	}
	spin_lock_init(&wdt_lock);
	boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
			WDIOF_CARDRESET : 0;
	ret = misc_register(&ixp4xx_wdt_miscdev);
	if (ret == 0)
		printk(KERN_INFO "IXP4xx Watchdog Timer: heartbeat %d sec\n",
			heartbeat);
	return ret;
}

static void __exit ixp4xx_wdt_exit(void)
{
	misc_deregister(&ixp4xx_wdt_miscdev);
}


module_init(ixp4xx_wdt_init);
module_exit(ixp4xx_wdt_exit);

MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
MODULE_DESCRIPTION("IXP4xx 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/ixp4xx_wdt.c
1da177e4 LT	3	*
	4	* Watchdog driver for Intel IXP4xx network processors
	5	*
	6	* Author: Deepak Saxena <dsaxena@plexity.net>
	7	*
	8	* Copyright 2004 (c) MontaVista, Software, Inc.
	9	* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
	10	*
	11	* This file is licensed under the terms of the GNU General Public
	12	* License version 2. This program is licensed "as is" without any
	13	* warranty of any kind, whether express or implied.
	14	*/
	15
1da177e4 LT	16	#include <linux/module.h>
	17	#include <linux/moduleparam.h>
	18	#include <linux/types.h>
	19	#include <linux/kernel.h>
	20	#include <linux/fs.h>
	21	#include <linux/miscdevice.h>
	22	#include <linux/watchdog.h>
	23	#include <linux/init.h>
	24	#include <linux/bitops.h>
089ab079	25	#include <linux/uaccess.h>
a09e64fb	26	#include <mach/hardware.h>
1da177e4	27
4bfdf378	28	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4 LT	29	static int heartbeat = 60; /* (secs) Default is 1 minute */
	30	static unsigned long wdt_status;
	31	static unsigned long boot_status;
9229376e	32	static DEFINE_SPINLOCK(wdt_lock);
1da177e4 LT	33
	34	#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
	35
	36	#define WDT_IN_USE 0
	37	#define WDT_OK_TO_CLOSE 1
	38
20d35f3e	39	static void wdt_enable(void)
1da177e4	40	{
20d35f3e	41	spin_lock(&wdt_lock);
1da177e4 LT	42	*IXP4XX_OSWK = IXP4XX_WDT_KEY;
	43	*IXP4XX_OSWE = 0;
	44	IXP4XX_OSWT = WDT_TICK_RATE heartbeat;
	45	*IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE \| IXP4XX_WDT_RESET_ENABLE;
	46	*IXP4XX_OSWK = 0;
20d35f3e	47	spin_unlock(&wdt_lock);
1da177e4 LT	48	}
1da177e4 LT	49
20d35f3e	50	static void wdt_disable(void)
1da177e4	51	{
20d35f3e	52	spin_lock(&wdt_lock);
1da177e4 LT	53	*IXP4XX_OSWK = IXP4XX_WDT_KEY;
	54	*IXP4XX_OSWE = 0;
	55	*IXP4XX_OSWK = 0;
20d35f3e	56	spin_unlock(&wdt_lock);
1da177e4 LT	57	}
1da177e4 LT	58
20d35f3e	59	static int ixp4xx_wdt_open(struct inode inode, struct file file)
1da177e4 LT	60	{
	61	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	62	return -EBUSY;
	63
	64	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
1da177e4	65	wdt_enable();
1da177e4 LT	66	return nonseekable_open(inode, file);
	67	}
	68
	69	static ssize_t
	70	ixp4xx_wdt_write(struct file file, const char data, size_t len, loff_t *ppos)
	71	{
	72	if (len) {
	73	if (!nowayout) {
	74	size_t i;
	75
	76	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	77
	78	for (i = 0; i != len; i++) {
	79	char c;
	80
	81	if (get_user(c, data + i))
	82	return -EFAULT;
	83	if (c == 'V')
	84	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	85	}
	86	}
	87	wdt_enable();
	88	}
1da177e4 LT	89	return len;
	90	}
	91
42747d71	92	static const struct watchdog_info ident = {
1da177e4 LT	93	.options = WDIOF_CARDRESET \| WDIOF_MAGICCLOSE \|
	94	WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	95	.identity = "IXP4xx Watchdog",
	96	};
	97
	98
20d35f3e AC	99	static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
20d35f3e AC	100	unsigned long arg)
1da177e4	101	{
795b89d2	102	int ret = -ENOTTY;
1da177e4 LT	103	int time;
	104
	105	switch (cmd) {
	106	case WDIOC_GETSUPPORT:
	107	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	108	sizeof(ident)) ? -EFAULT : 0;
	109	break;
	110
	111	case WDIOC_GETSTATUS:
	112	ret = put_user(0, (int *)arg);
	113	break;
	114
	115	case WDIOC_GETBOOTSTATUS:
	116	ret = put_user(boot_status, (int *)arg);
	117	break;
	118
0c06090c WVS	119	case WDIOC_KEEPALIVE:
	120	wdt_enable();
	121	ret = 0;
	122	break;
	123
1da177e4 LT	124	case WDIOC_SETTIMEOUT:
	125	ret = get_user(time, (int *)arg);
	126	if (ret)
	127	break;
	128
	129	if (time <= 0 \|\| time > 60) {
	130	ret = -EINVAL;
	131	break;
	132	}
	133
	134	heartbeat = time;
	135	wdt_enable();
	136	/* Fall through */
	137
	138	case WDIOC_GETTIMEOUT:
	139	ret = put_user(heartbeat, (int *)arg);
	140	break;
1da177e4 LT	141	}
	142	return ret;
	143	}
	144
20d35f3e	145	static int ixp4xx_wdt_release(struct inode inode, struct file file)
1da177e4	146	{
20d35f3e	147	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
1da177e4	148	wdt_disable();
20d35f3e	149	else
b36bbb6c	150	printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
1da177e4	151	"timer will not stop\n");
1da177e4 LT	152	clear_bit(WDT_IN_USE, &wdt_status);
	153	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	154
	155	return 0;
	156	}
	157
	158
7944d3a5	159	static const struct file_operations ixp4xx_wdt_fops = {
1da177e4 LT	160	.owner = THIS_MODULE,
	161	.llseek = no_llseek,
	162	.write = ixp4xx_wdt_write,
20d35f3e	163	.unlocked_ioctl = ixp4xx_wdt_ioctl,
1da177e4 LT	164	.open = ixp4xx_wdt_open,
	165	.release = ixp4xx_wdt_release,
	166	};
	167
7944d3a5	168	static struct miscdevice ixp4xx_wdt_miscdev = {
1da177e4	169	.minor = WATCHDOG_MINOR,
2dab3cab	170	.name = "watchdog",
1da177e4 LT	171	.fops = &ixp4xx_wdt_fops,
	172	};
	173
	174	static int __init ixp4xx_wdt_init(void)
	175	{
	176	int ret;
1da177e4	177
0ba8b9b2	178	if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
7944d3a5 WVS	179	printk(KERN_ERR "IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected"
7944d3a5 WVS	180	" - watchdog disabled\n");
1da177e4 LT	181
	182	return -ENODEV;
	183	}
20d35f3e	184	spin_lock_init(&wdt_lock);
1da177e4 LT	185	boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
1da177e4 LT	186	WDIOF_CARDRESET : 0;
1da177e4 LT	187	ret = misc_register(&ixp4xx_wdt_miscdev);
1da177e4 LT	188	if (ret == 0)
7944d3a5 WVS	189	printk(KERN_INFO "IXP4xx Watchdog Timer: heartbeat %d sec\n",
7944d3a5 WVS	190	heartbeat);
1da177e4 LT	191	return ret;
	192	}
	193
	194	static void __exit ixp4xx_wdt_exit(void)
	195	{
	196	misc_deregister(&ixp4xx_wdt_miscdev);
	197	}
	198
	199
	200	module_init(ixp4xx_wdt_init);
	201	module_exit(ixp4xx_wdt_exit);
	202
	203	MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
	204	MODULE_DESCRIPTION("IXP4xx 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