[mirror_ubuntu-zesty-kernel.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 <asm/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 spin_lock_t 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 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_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;

	case WDIOC_KEEPALIVE:
		wdt_enable();
		ret = 0;
		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;
	unsigned long processor_id;

	asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :);
	if (!(processor_id & 0xf) && !cpu_is_ixp46x()) {
		printk("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("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>
1da177e4 LT	26
1da177e4 LT	27	#include <asm/hardware.h>
1da177e4	28
4bfdf378	29	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4 LT	30	static int heartbeat = 60; /* (secs) Default is 1 minute */
	31	static unsigned long wdt_status;
	32	static unsigned long boot_status;
20d35f3e	33	static spin_lock_t wdt_lock;
1da177e4 LT	34
	35	#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
	36
	37	#define WDT_IN_USE 0
	38	#define WDT_OK_TO_CLOSE 1
	39
20d35f3e	40	static void wdt_enable(void)
1da177e4	41	{
20d35f3e	42	spin_lock(&wdt_lock);
1da177e4 LT	43	*IXP4XX_OSWK = IXP4XX_WDT_KEY;
	44	*IXP4XX_OSWE = 0;
	45	IXP4XX_OSWT = WDT_TICK_RATE heartbeat;
	46	*IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE \| IXP4XX_WDT_RESET_ENABLE;
	47	*IXP4XX_OSWK = 0;
20d35f3e	48	spin_unlock(&wdt_lock);
1da177e4 LT	49	}
1da177e4 LT	50
20d35f3e	51	static void wdt_disable(void)
1da177e4	52	{
20d35f3e	53	spin_lock(&wdt_lock);
1da177e4 LT	54	*IXP4XX_OSWK = IXP4XX_WDT_KEY;
	55	*IXP4XX_OSWE = 0;
	56	*IXP4XX_OSWK = 0;
20d35f3e	57	spin_unlock(&wdt_lock);
1da177e4 LT	58	}
1da177e4 LT	59
20d35f3e	60	static int ixp4xx_wdt_open(struct inode inode, struct file file)
1da177e4 LT	61	{
	62	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	63	return -EBUSY;
	64
	65	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
1da177e4	66	wdt_enable();
1da177e4 LT	67	return nonseekable_open(inode, file);
	68	}
	69
	70	static ssize_t
	71	ixp4xx_wdt_write(struct file file, const char data, size_t len, loff_t *ppos)
	72	{
	73	if (len) {
	74	if (!nowayout) {
	75	size_t i;
	76
	77	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	78
	79	for (i = 0; i != len; i++) {
	80	char c;
	81
	82	if (get_user(c, data + i))
	83	return -EFAULT;
	84	if (c == 'V')
	85	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	86	}
	87	}
	88	wdt_enable();
	89	}
1da177e4 LT	90	return len;
	91	}
	92
	93	static struct watchdog_info ident = {
	94	.options = WDIOF_CARDRESET \| WDIOF_MAGICCLOSE \|
	95	WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	96	.identity = "IXP4xx Watchdog",
	97	};
	98
	99
20d35f3e AC	100	static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
20d35f3e AC	101	unsigned long arg)
1da177e4	102	{
795b89d2	103	int ret = -ENOTTY;
1da177e4 LT	104	int time;
	105
	106	switch (cmd) {
	107	case WDIOC_GETSUPPORT:
	108	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	109	sizeof(ident)) ? -EFAULT : 0;
	110	break;
	111
	112	case WDIOC_GETSTATUS:
	113	ret = put_user(0, (int *)arg);
	114	break;
	115
	116	case WDIOC_GETBOOTSTATUS:
	117	ret = put_user(boot_status, (int *)arg);
	118	break;
	119
	120	case WDIOC_SETTIMEOUT:
	121	ret = get_user(time, (int *)arg);
	122	if (ret)
	123	break;
	124
	125	if (time <= 0 \|\| time > 60) {
	126	ret = -EINVAL;
	127	break;
	128	}
	129
	130	heartbeat = time;
	131	wdt_enable();
	132	/* Fall through */
	133
	134	case WDIOC_GETTIMEOUT:
	135	ret = put_user(heartbeat, (int *)arg);
	136	break;
	137
	138	case WDIOC_KEEPALIVE:
	139	wdt_enable();
	140	ret = 0;
	141	break;
	142	}
	143	return ret;
	144	}
	145
20d35f3e	146	static int ixp4xx_wdt_release(struct inode inode, struct file file)
1da177e4	147	{
20d35f3e	148	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
1da177e4	149	wdt_disable();
20d35f3e	150	else
b36bbb6c	151	printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
1da177e4	152	"timer will not stop\n");
1da177e4 LT	153	clear_bit(WDT_IN_USE, &wdt_status);
	154	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	155
	156	return 0;
	157	}
	158
	159
62322d25	160	static const struct file_operations ixp4xx_wdt_fops =
1da177e4 LT	161	{
	162	.owner = THIS_MODULE,
	163	.llseek = no_llseek,
	164	.write = ixp4xx_wdt_write,
20d35f3e	165	.unlocked_ioctl = ixp4xx_wdt_ioctl,
1da177e4 LT	166	.open = ixp4xx_wdt_open,
	167	.release = ixp4xx_wdt_release,
	168	};
	169
	170	static struct miscdevice ixp4xx_wdt_miscdev =
	171	{
	172	.minor = WATCHDOG_MINOR,
2dab3cab	173	.name = "watchdog",
1da177e4 LT	174	.fops = &ixp4xx_wdt_fops,
	175	};
	176
	177	static int __init ixp4xx_wdt_init(void)
	178	{
	179	int ret;
	180	unsigned long processor_id;
	181
	182	asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :);
3adfd4e2 DS	183	if (!(processor_id & 0xf) && !cpu_is_ixp46x()) {
3adfd4e2 DS	184	printk("IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected - "
1da177e4 LT	185	"watchdog disabled\n");
	186
	187	return -ENODEV;
	188	}
20d35f3e AC	189	spin_lock_init(&wdt_lock);
	190	boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
	191	WDIOF_CARDRESET : 0;
1da177e4 LT	192	ret = misc_register(&ixp4xx_wdt_miscdev);
	193	if (ret == 0)
	194	printk("IXP4xx Watchdog Timer: heartbeat %d sec\n", heartbeat);
1da177e4 LT	195	return ret;
	196	}
	197
	198	static void __exit ixp4xx_wdt_exit(void)
	199	{
	200	misc_deregister(&ixp4xx_wdt_miscdev);
	201	}
	202
	203
	204	module_init(ixp4xx_wdt_init);
	205	module_exit(ixp4xx_wdt_exit);
	206
	207	MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
	208	MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
	209
	210	module_param(heartbeat, int, 0);
	211	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
	212
	213	module_param(nowayout, int, 0);
	214	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	215
	216	MODULE_LICENSE("GPL");
	217	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	218