[deliverable/linux.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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/timer.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 unsigned int heartbeat = 60;	/* (secs) Default is 1 minute */
static unsigned long wdt_status;
static DEFINE_SPINLOCK(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 const 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
		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 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) {
		pr_info("Unable to use IXP2000 watchdog due to IXP2800 erratum #25\n");
		return -EIO;
	}
	wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
	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, bool, 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
27c766aa JP	19	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	20
1da177e4 LT	21	#include <linux/module.h>
	22	#include <linux/moduleparam.h>
	23	#include <linux/types.h>
e605d554	24	#include <linux/timer.h>
1da177e4 LT	25	#include <linux/kernel.h>
	26	#include <linux/fs.h>
	27	#include <linux/miscdevice.h>
	28	#include <linux/watchdog.h>
	29	#include <linux/init.h>
	30	#include <linux/bitops.h>
640b4f68	31	#include <linux/uaccess.h>
a09e64fb	32	#include <mach/hardware.h>
1da177e4	33
86a1e189	34	static bool nowayout = WATCHDOG_NOWAYOUT;
1da177e4 LT	35	static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */
1da177e4 LT	36	static unsigned long wdt_status;
1334f329	37	static DEFINE_SPINLOCK(wdt_lock);
1da177e4 LT	38
	39	#define WDT_IN_USE 0
	40	#define WDT_OK_TO_CLOSE 1
	41
	42	static unsigned long wdt_tick_rate;
	43
640b4f68	44	static void wdt_enable(void)
1da177e4	45	{
640b4f68	46	spin_lock(&wdt_lock);
1da177e4 LT	47	ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) \| WDT_RESET_ENABLE);
	48	ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
	49	ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
	50	ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 \| TIMER_ENABLE);
640b4f68	51	spin_unlock(&wdt_lock);
1da177e4 LT	52	}
1da177e4 LT	53
640b4f68	54	static void wdt_disable(void)
1da177e4	55	{
640b4f68	56	spin_lock(&wdt_lock);
1da177e4	57	ixp2000_reg_write(IXP2000_T4_CTL, 0);
640b4f68	58	spin_unlock(&wdt_lock);
1da177e4 LT	59	}
1da177e4 LT	60
640b4f68	61	static void wdt_keepalive(void)
1da177e4	62	{
640b4f68	63	spin_lock(&wdt_lock);
1da177e4	64	ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
640b4f68	65	spin_unlock(&wdt_lock);
1da177e4 LT	66	}
1da177e4 LT	67
640b4f68	68	static int ixp2000_wdt_open(struct inode inode, struct file file)
1da177e4 LT	69	{
	70	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	71	return -EBUSY;
	72
	73	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	74
	75	wdt_enable();
	76
	77	return nonseekable_open(inode, file);
	78	}
	79
640b4f68 AC	80	static ssize_t ixp2000_wdt_write(struct file file, const char data,
640b4f68 AC	81	size_t len, loff_t *ppos)
1da177e4 LT	82	{
	83	if (len) {
	84	if (!nowayout) {
	85	size_t i;
	86
	87	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	88
	89	for (i = 0; i != len; i++) {
	90	char c;
	91
	92	if (get_user(c, data + i))
	93	return -EFAULT;
	94	if (c == 'V')
	95	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	96	}
	97	}
	98	wdt_keepalive();
	99	}
	100
	101	return len;
	102	}
	103
	104
42747d71	105	static const struct watchdog_info ident = {
1da177e4 LT	106	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \|
	107	WDIOF_KEEPALIVEPING,
	108	.identity = "IXP2000 Watchdog",
	109	};
	110
640b4f68 AC	111	static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd,
640b4f68 AC	112	unsigned long arg)
1da177e4	113	{
795b89d2	114	int ret = -ENOTTY;
1da177e4 LT	115	int time;
	116
	117	switch (cmd) {
	118	case WDIOC_GETSUPPORT:
	119	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	120	sizeof(ident)) ? -EFAULT : 0;
	121	break;
	122
	123	case WDIOC_GETSTATUS:
	124	ret = put_user(0, (int *)arg);
	125	break;
	126
	127	case WDIOC_GETBOOTSTATUS:
	128	ret = put_user(0, (int *)arg);
	129	break;
	130
0c06090c WVS	131	case WDIOC_KEEPALIVE:
	132	wdt_enable();
	133	ret = 0;
	134	break;
	135
1da177e4 LT	136	case WDIOC_SETTIMEOUT:
	137	ret = get_user(time, (int *)arg);
	138	if (ret)
	139	break;
	140
	141	if (time <= 0 \|\| time > 60) {
	142	ret = -EINVAL;
	143	break;
	144	}
	145
	146	heartbeat = time;
	147	wdt_keepalive();
	148	/* Fall through */
	149
	150	case WDIOC_GETTIMEOUT:
	151	ret = put_user(heartbeat, (int *)arg);
	152	break;
1da177e4 LT	153	}
	154
	155	return ret;
	156	}
	157
640b4f68	158	static int ixp2000_wdt_release(struct inode inode, struct file file)
1da177e4	159	{
640b4f68	160	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
1da177e4	161	wdt_disable();
640b4f68	162	else
27c766aa	163	pr_crit("Device closed unexpectedly - timer will not stop\n");
1da177e4 LT	164	clear_bit(WDT_IN_USE, &wdt_status);
	165	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	166
	167	return 0;
	168	}
	169
	170
640b4f68	171	static const struct file_operations ixp2000_wdt_fops = {
1da177e4 LT	172	.owner = THIS_MODULE,
	173	.llseek = no_llseek,
	174	.write = ixp2000_wdt_write,
640b4f68	175	.unlocked_ioctl = ixp2000_wdt_ioctl,
1da177e4 LT	176	.open = ixp2000_wdt_open,
	177	.release = ixp2000_wdt_release,
	178	};
	179
640b4f68	180	static struct miscdevice ixp2000_wdt_miscdev = {
1da177e4	181	.minor = WATCHDOG_MINOR,
2dab3cab	182	.name = "watchdog",
1da177e4 LT	183	.fops = &ixp2000_wdt_fops,
	184	};
	185
	186	static int __init ixp2000_wdt_init(void)
	187	{
e4fe1981	188	if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
27c766aa	189	pr_info("Unable to use IXP2000 watchdog due to IXP2800 erratum #25\n");
e4fe1981 LB	190	return -EIO;
e4fe1981 LB	191	}
e4fe1981	192	wdt_tick_rate = (IXP2000_T1_CLD HZ) / 256;
1da177e4 LT	193	return misc_register(&ixp2000_wdt_miscdev);
	194	}
	195
	196	static void __exit ixp2000_wdt_exit(void)
	197	{
	198	misc_deregister(&ixp2000_wdt_miscdev);
	199	}
	200
	201	module_init(ixp2000_wdt_init);
	202	module_exit(ixp2000_wdt_exit);
	203
632155e6	204	MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
1da177e4 LT	205	MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
	206
	207	module_param(heartbeat, int, 0);
	208	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
	209
86a1e189	210	module_param(nowayout, bool, 0);
1da177e4 LT	211	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	212
	213	MODULE_LICENSE("GPL");
	214	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	215