[deliverable/linux.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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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 bool 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
		pr_crit("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()) {
		pr_err("Rev. A0 IXP42x CPU detected - watchdog disabled\n");

		return -ENODEV;
	}
	boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
			WDIOF_CARDRESET : 0;
	ret = misc_register(&ixp4xx_wdt_miscdev);
	if (ret == 0)
		pr_info("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, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");

MODULE_LICENSE("GPL");
Commit	Line	Data
	1	/*
	2	* drivers/char/watchdog/ixp4xx_wdt.c
	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
	16	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	17
	18	#include <linux/module.h>
	19	#include <linux/moduleparam.h>
	20	#include <linux/types.h>
	21	#include <linux/kernel.h>
	22	#include <linux/fs.h>
	23	#include <linux/miscdevice.h>
	24	#include <linux/watchdog.h>
	25	#include <linux/init.h>
	26	#include <linux/bitops.h>
	27	#include <linux/uaccess.h>
	28	#include <mach/hardware.h>
	29
	30	static bool nowayout = WATCHDOG_NOWAYOUT;
	31	static int heartbeat = 60; /* (secs) Default is 1 minute */
	32	static unsigned long wdt_status;
	33	static unsigned long boot_status;
	34	static DEFINE_SPINLOCK(wdt_lock);
	35
	36	#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
	37
	38	#define WDT_IN_USE 0
	39	#define WDT_OK_TO_CLOSE 1
	40
	41	static void wdt_enable(void)
	42	{
	43	spin_lock(&wdt_lock);
	44	*IXP4XX_OSWK = IXP4XX_WDT_KEY;
	45	*IXP4XX_OSWE = 0;
	46	IXP4XX_OSWT = WDT_TICK_RATE heartbeat;
	47	*IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE \| IXP4XX_WDT_RESET_ENABLE;
	48	*IXP4XX_OSWK = 0;
	49	spin_unlock(&wdt_lock);
	50	}
	51
	52	static void wdt_disable(void)
	53	{
	54	spin_lock(&wdt_lock);
	55	*IXP4XX_OSWK = IXP4XX_WDT_KEY;
	56	*IXP4XX_OSWE = 0;
	57	*IXP4XX_OSWK = 0;
	58	spin_unlock(&wdt_lock);
	59	}
	60
	61	static int ixp4xx_wdt_open(struct inode inode, struct file file)
	62	{
	63	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	64	return -EBUSY;
	65
	66	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	67	wdt_enable();
	68	return nonseekable_open(inode, file);
	69	}
	70
	71	static ssize_t
	72	ixp4xx_wdt_write(struct file file, const char data, size_t len, loff_t *ppos)
	73	{
	74	if (len) {
	75	if (!nowayout) {
	76	size_t i;
	77
	78	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	79
	80	for (i = 0; i != len; i++) {
	81	char c;
	82
	83	if (get_user(c, data + i))
	84	return -EFAULT;
	85	if (c == 'V')
	86	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	87	}
	88	}
	89	wdt_enable();
	90	}
	91	return len;
	92	}
	93
	94	static const struct watchdog_info ident = {
	95	.options = WDIOF_CARDRESET \| WDIOF_MAGICCLOSE \|
	96	WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	97	.identity = "IXP4xx Watchdog",
	98	};
	99
	100
	101	static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
	102	unsigned long arg)
	103	{
	104	int ret = -ENOTTY;
	105	int time;
	106
	107	switch (cmd) {
	108	case WDIOC_GETSUPPORT:
	109	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	110	sizeof(ident)) ? -EFAULT : 0;
	111	break;
	112
	113	case WDIOC_GETSTATUS:
	114	ret = put_user(0, (int *)arg);
	115	break;
	116
	117	case WDIOC_GETBOOTSTATUS:
	118	ret = put_user(boot_status, (int *)arg);
	119	break;
	120
	121	case WDIOC_KEEPALIVE:
	122	wdt_enable();
	123	ret = 0;
	124	break;
	125
	126	case WDIOC_SETTIMEOUT:
	127	ret = get_user(time, (int *)arg);
	128	if (ret)
	129	break;
	130
	131	if (time <= 0 \|\| time > 60) {
	132	ret = -EINVAL;
	133	break;
	134	}
	135
	136	heartbeat = time;
	137	wdt_enable();
	138	/* Fall through */
	139
	140	case WDIOC_GETTIMEOUT:
	141	ret = put_user(heartbeat, (int *)arg);
	142	break;
	143	}
	144	return ret;
	145	}
	146
	147	static int ixp4xx_wdt_release(struct inode inode, struct file file)
	148	{
	149	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
	150	wdt_disable();
	151	else
	152	pr_crit("Device closed unexpectedly - timer will not stop\n");
	153	clear_bit(WDT_IN_USE, &wdt_status);
	154	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	155
	156	return 0;
	157	}
	158
	159
	160	static const struct file_operations ixp4xx_wdt_fops = {
	161	.owner = THIS_MODULE,
	162	.llseek = no_llseek,
	163	.write = ixp4xx_wdt_write,
	164	.unlocked_ioctl = ixp4xx_wdt_ioctl,
	165	.open = ixp4xx_wdt_open,
	166	.release = ixp4xx_wdt_release,
	167	};
	168
	169	static struct miscdevice ixp4xx_wdt_miscdev = {
	170	.minor = WATCHDOG_MINOR,
	171	.name = "watchdog",
	172	.fops = &ixp4xx_wdt_fops,
	173	};
	174
	175	static int __init ixp4xx_wdt_init(void)
	176	{
	177	int ret;
	178
	179	if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
	180	pr_err("Rev. A0 IXP42x CPU detected - watchdog disabled\n");
	181
	182	return -ENODEV;
	183	}
	184	boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
	185	WDIOF_CARDRESET : 0;
	186	ret = misc_register(&ixp4xx_wdt_miscdev);
	187	if (ret == 0)
	188	pr_info("timer heartbeat %d sec\n", heartbeat);
	189	return ret;
	190	}
	191
	192	static void __exit ixp4xx_wdt_exit(void)
	193	{
	194	misc_deregister(&ixp4xx_wdt_miscdev);
	195	}
	196
	197
	198	module_init(ixp4xx_wdt_init);
	199	module_exit(ixp4xx_wdt_exit);
	200
	201	MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
	202	MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
	203
	204	module_param(heartbeat, int, 0);
	205	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
	206
	207	module_param(nowayout, bool, 0);
	208	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	209
	210	MODULE_LICENSE("GPL");