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

/*
 * drivers/char/watchdog/iop_wdt.c
 *
 * WDT driver for Intel I/O Processors
 * Copyright (C) 2005, Intel Corporation.
 *
 * Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 *	Curt E Bruns <curt.e.bruns@intel.com>
 *	Peter Milne <peter.milne@d-tacq.com>
 *	Dan Williams <dan.j.williams@intel.com>
 */

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

static int nowayout = WATCHDOG_NOWAYOUT;
static unsigned long wdt_status;
static unsigned long boot_status;
static spinlock_t wdt_lock;

#define WDT_IN_USE		0
#define WDT_OK_TO_CLOSE		1
#define WDT_ENABLED		2

static unsigned long iop_watchdog_timeout(void)
{
	return (0xffffffffUL / get_iop_tick_rate());
}

/**
 * wdt_supports_disable - determine if we are accessing a iop13xx watchdog
 * or iop3xx by whether it has a disable command
 */
static int wdt_supports_disable(void)
{
	int can_disable;

	if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM)
		can_disable = 1;
	else
		can_disable = 0;

	return can_disable;
}

static void wdt_enable(void)
{
	/* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF
	 * Takes approx. 10.7s to timeout
	 */
	spin_lock(&wdt_lock);
	write_wdtcr(IOP_WDTCR_EN_ARM);
	write_wdtcr(IOP_WDTCR_EN);
	spin_unlock(&wdt_lock);
}

/* returns 0 if the timer was successfully disabled */
static int wdt_disable(void)
{
	/* Stop Counting */
	if (wdt_supports_disable()) {
		spin_lock(&wdt_lock);
		write_wdtcr(IOP_WDTCR_DIS_ARM);
		write_wdtcr(IOP_WDTCR_DIS);
		clear_bit(WDT_ENABLED, &wdt_status);
		spin_unlock(&wdt_lock);
		printk(KERN_INFO "WATCHDOG: Disabled\n");
		return 0;
	} else
		return 1;
}

static int iop_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();
	set_bit(WDT_ENABLED, &wdt_status);
	return nonseekable_open(inode, file);
}

static ssize_t iop_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_KEEPALIVEPING,
	.identity = "iop watchdog",
};

static long iop_wdt_ioctl(struct file *file,
				unsigned int cmd, unsigned long arg)
{
	int options;
	int ret = -ENOTTY;
	int __user *argp = (int __user *)arg;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &ident, sizeof(ident)))
			ret = -EFAULT;
		else
			ret = 0;
		break;

	case WDIOC_GETSTATUS:
		ret = put_user(0, argp);
		break;

	case WDIOC_GETBOOTSTATUS:
		ret = put_user(boot_status, argp);
		break;

	case WDIOC_SETOPTIONS:
		if (get_user(options, (int *)arg))
			return -EFAULT;

		if (options & WDIOS_DISABLECARD) {
			if (!nowayout) {
				if (wdt_disable() == 0) {
					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
					ret = 0;
				} else
					ret = -ENXIO;
			} else
				ret = 0;
		}
		if (options & WDIOS_ENABLECARD) {
			wdt_enable();
			ret = 0;
		}
		break;

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

	case WDIOC_GETTIMEOUT:
		ret = put_user(iop_watchdog_timeout(), argp);
		break;
	}
	return ret;
}

static int iop_wdt_release(struct inode *inode, struct file *file)
{
	int state = 1;
	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
		if (test_bit(WDT_ENABLED, &wdt_status))
			state = wdt_disable();

	/* if the timer is not disabled reload and notify that we are still
	 * going down
	 */
	if (state != 0) {
		wdt_enable();
		printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
		       "reset in %lu seconds\n", iop_watchdog_timeout());
	}

	clear_bit(WDT_IN_USE, &wdt_status);
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	return 0;
}

static const struct file_operations iop_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = iop_wdt_write,
	.unlocked_ioctl = iop_wdt_ioctl,
	.open = iop_wdt_open,
	.release = iop_wdt_release,
};

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

static int __init iop_wdt_init(void)
{
	int ret;

	spin_lock_init(&wdt_lock);


	/* check if the reset was caused by the watchdog timer */
	boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0;

	/* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset
	 * NOTE: An IB Reset will Reset both cores in the IOP342
	 */
	write_wdtsr(IOP13XX_WDTCR_IB_RESET);

	/* Register after we have the device set up so we cannot race
	   with an open */
	ret = misc_register(&iop_wdt_miscdev);
	if (ret == 0)
		printk(KERN_INFO "iop watchdog timer: timeout %lu sec\n",
		       iop_watchdog_timeout());

	return ret;
}

static void __exit iop_wdt_exit(void)
{
	misc_deregister(&iop_wdt_miscdev);
}

module_init(iop_wdt_init);
module_exit(iop_wdt_exit);

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

MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>");
MODULE_DESCRIPTION("iop watchdog timer driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
70c14ff0 DW	1	/*
	2	* drivers/char/watchdog/iop_wdt.c
	3	*
	4	* WDT driver for Intel I/O Processors
	5	* Copyright (C) 2005, Intel Corporation.
	6	*
	7	* Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc.
	8	*
	9	* This program is free software; you can redistribute it and/or modify it
	10	* under the terms and conditions of the GNU General Public License,
	11	* version 2, as published by the Free Software Foundation.
	12	*
	13	* This program is distributed in the hope it will be useful, but WITHOUT
	14	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	15	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	16	* more details.
	17	*
	18	* You should have received a copy of the GNU General Public License along with
	19	* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
	20	* Place - Suite 330, Boston, MA 02111-1307 USA.
	21	*
	22	* Curt E Bruns <curt.e.bruns@intel.com>
	23	* Peter Milne <peter.milne@d-tacq.com>
	24	* Dan Williams <dan.j.williams@intel.com>
	25	*/
	26
	27	#include <linux/module.h>
	28	#include <linux/kernel.h>
	29	#include <linux/fs.h>
	30	#include <linux/init.h>
	31	#include <linux/device.h>
	32	#include <linux/miscdevice.h>
	33	#include <linux/watchdog.h>
	34	#include <linux/uaccess.h>
a09e64fb	35	#include <mach/hardware.h>
70c14ff0 DW	36
	37	static int nowayout = WATCHDOG_NOWAYOUT;
	38	static unsigned long wdt_status;
	39	static unsigned long boot_status;
02e3814e	40	static spinlock_t wdt_lock;
70c14ff0 DW	41
	42	#define WDT_IN_USE 0
	43	#define WDT_OK_TO_CLOSE 1
	44	#define WDT_ENABLED 2
	45
	46	static unsigned long iop_watchdog_timeout(void)
	47	{
	48	return (0xffffffffUL / get_iop_tick_rate());
	49	}
	50
	51	/**
	52	* wdt_supports_disable - determine if we are accessing a iop13xx watchdog
	53	* or iop3xx by whether it has a disable command
	54	*/
	55	static int wdt_supports_disable(void)
	56	{
	57	int can_disable;
	58
	59	if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM)
	60	can_disable = 1;
	61	else
	62	can_disable = 0;
	63
	64	return can_disable;
	65	}
	66
	67	static void wdt_enable(void)
	68	{
	69	/* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF
	70	* Takes approx. 10.7s to timeout
	71	*/
02e3814e	72	spin_lock(&wdt_lock);
70c14ff0 DW	73	write_wdtcr(IOP_WDTCR_EN_ARM);
70c14ff0 DW	74	write_wdtcr(IOP_WDTCR_EN);
02e3814e	75	spin_unlock(&wdt_lock);
70c14ff0 DW	76	}
	77
	78	/* returns 0 if the timer was successfully disabled */
	79	static int wdt_disable(void)
	80	{
	81	/* Stop Counting */
	82	if (wdt_supports_disable()) {
02e3814e	83	spin_lock(&wdt_lock);
70c14ff0 DW	84	write_wdtcr(IOP_WDTCR_DIS_ARM);
	85	write_wdtcr(IOP_WDTCR_DIS);
	86	clear_bit(WDT_ENABLED, &wdt_status);
02e3814e	87	spin_unlock(&wdt_lock);
70c14ff0 DW	88	printk(KERN_INFO "WATCHDOG: Disabled\n");
	89	return 0;
	90	} else
	91	return 1;
	92	}
	93
	94	static int iop_wdt_open(struct inode inode, struct file file)
	95	{
	96	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	97	return -EBUSY;
	98
	99	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
70c14ff0	100	wdt_enable();
70c14ff0	101	set_bit(WDT_ENABLED, &wdt_status);
70c14ff0 DW	102	return nonseekable_open(inode, file);
	103	}
	104
02e3814e	105	static ssize_t iop_wdt_write(struct file file, const char data, size_t len,
70c14ff0 DW	106	loff_t *ppos)
	107	{
	108	if (len) {
	109	if (!nowayout) {
	110	size_t i;
	111
	112	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	113
	114	for (i = 0; i != len; i++) {
	115	char c;
	116
	117	if (get_user(c, data + i))
	118	return -EFAULT;
	119	if (c == 'V')
	120	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	121	}
	122	}
	123	wdt_enable();
	124	}
70c14ff0 DW	125	return len;
	126	}
	127
02e3814e	128	static const struct watchdog_info ident = {
70c14ff0 DW	129	.options = WDIOF_CARDRESET \| WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING,
	130	.identity = "iop watchdog",
	131	};
	132
02e3814e AC	133	static long iop_wdt_ioctl(struct file *file,
02e3814e AC	134	unsigned int cmd, unsigned long arg)
70c14ff0 DW	135	{
	136	int options;
	137	int ret = -ENOTTY;
02e3814e	138	int __user argp = (int __user )arg;
70c14ff0 DW	139
	140	switch (cmd) {
	141	case WDIOC_GETSUPPORT:
e04ab958	142	if (copy_to_user(argp, &ident, sizeof(ident)))
70c14ff0 DW	143	ret = -EFAULT;
	144	else
	145	ret = 0;
	146	break;
	147
	148	case WDIOC_GETSTATUS:
02e3814e	149	ret = put_user(0, argp);
70c14ff0 DW	150	break;
	151
	152	case WDIOC_GETBOOTSTATUS:
02e3814e	153	ret = put_user(boot_status, argp);
70c14ff0 DW	154	break;
	155
	156	case WDIOC_SETOPTIONS:
	157	if (get_user(options, (int *)arg))
	158	return -EFAULT;
	159
	160	if (options & WDIOS_DISABLECARD) {
	161	if (!nowayout) {
	162	if (wdt_disable() == 0) {
	163	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	164	ret = 0;
	165	} else
	166	ret = -ENXIO;
	167	} else
	168	ret = 0;
	169	}
70c14ff0 DW	170	if (options & WDIOS_ENABLECARD) {
	171	wdt_enable();
	172	ret = 0;
	173	}
	174	break;
70c14ff0	175
0c06090c WVS	176	case WDIOC_KEEPALIVE:
	177	wdt_enable();
	178	ret = 0;
	179	break;
	180
	181	case WDIOC_GETTIMEOUT:
	182	ret = put_user(iop_watchdog_timeout(), argp);
	183	break;
70c14ff0	184	}
70c14ff0 DW	185	return ret;
	186	}
	187
	188	static int iop_wdt_release(struct inode inode, struct file file)
	189	{
	190	int state = 1;
	191	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
	192	if (test_bit(WDT_ENABLED, &wdt_status))
	193	state = wdt_disable();
	194
4b512d26	195	/* if the timer is not disabled reload and notify that we are still
70c14ff0 DW	196	* going down
	197	*/
	198	if (state != 0) {
	199	wdt_enable();
	200	printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
	201	"reset in %lu seconds\n", iop_watchdog_timeout());
	202	}
	203
	204	clear_bit(WDT_IN_USE, &wdt_status);
	205	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	206
	207	return 0;
	208	}
	209
	210	static const struct file_operations iop_wdt_fops = {
	211	.owner = THIS_MODULE,
	212	.llseek = no_llseek,
	213	.write = iop_wdt_write,
02e3814e	214	.unlocked_ioctl = iop_wdt_ioctl,
70c14ff0 DW	215	.open = iop_wdt_open,
	216	.release = iop_wdt_release,
	217	};
	218
	219	static struct miscdevice iop_wdt_miscdev = {
	220	.minor = WATCHDOG_MINOR,
	221	.name = "watchdog",
	222	.fops = &iop_wdt_fops,
	223	};
	224
	225	static int __init iop_wdt_init(void)
	226	{
	227	int ret;
	228
02e3814e AC	229	spin_lock_init(&wdt_lock);
02e3814e AC	230
70c14ff0 DW	231
	232	/* check if the reset was caused by the watchdog timer */
	233	boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0;
	234
	235	/* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset
	236	* NOTE: An IB Reset will Reset both cores in the IOP342
	237	*/
	238	write_wdtsr(IOP13XX_WDTCR_IB_RESET);
	239
02e3814e AC	240	/* Register after we have the device set up so we cannot race
	241	with an open */
	242	ret = misc_register(&iop_wdt_miscdev);
	243	if (ret == 0)
7944d3a5	244	printk(KERN_INFO "iop watchdog timer: timeout %lu sec\n",
02e3814e AC	245	iop_watchdog_timeout());
02e3814e AC	246
70c14ff0 DW	247	return ret;
	248	}
	249
	250	static void __exit iop_wdt_exit(void)
	251	{
	252	misc_deregister(&iop_wdt_miscdev);
	253	}
	254
	255	module_init(iop_wdt_init);
	256	module_exit(iop_wdt_exit);
	257
	258	module_param(nowayout, int, 0);
	259	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	260
	261	MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>");
	262	MODULE_DESCRIPTION("iop watchdog timer driver");
	263	MODULE_LICENSE("GPL");
	264	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);