[linux-2.6-block.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/of.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 stream_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;

	/*
	 * FIXME: we bail out on device tree boot but this really needs
	 * to be fixed in a nicer way: this registers the MDIO bus before
	 * even matching the driver infrastructure, we should only probe
	 * detected hardware.
	 */
	if (of_have_populated_dt())
		return -ENODEV;
	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
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
27c766aa JP	16	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	17
1da177e4 LT	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>
9540724c	24	#include <linux/of.h>
1da177e4 LT	25	#include <linux/watchdog.h>
	26	#include <linux/init.h>
	27	#include <linux/bitops.h>
089ab079	28	#include <linux/uaccess.h>
a09e64fb	29	#include <mach/hardware.h>
1da177e4	30
86a1e189	31	static bool nowayout = WATCHDOG_NOWAYOUT;
1da177e4 LT	32	static int heartbeat = 60; /* (secs) Default is 1 minute */
	33	static unsigned long wdt_status;
	34	static unsigned long boot_status;
9229376e	35	static DEFINE_SPINLOCK(wdt_lock);
1da177e4 LT	36
	37	#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
	38
	39	#define WDT_IN_USE 0
	40	#define WDT_OK_TO_CLOSE 1
	41
20d35f3e	42	static void wdt_enable(void)
1da177e4	43	{
20d35f3e	44	spin_lock(&wdt_lock);
1da177e4 LT	45	*IXP4XX_OSWK = IXP4XX_WDT_KEY;
	46	*IXP4XX_OSWE = 0;
	47	IXP4XX_OSWT = WDT_TICK_RATE heartbeat;
	48	*IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE \| IXP4XX_WDT_RESET_ENABLE;
	49	*IXP4XX_OSWK = 0;
20d35f3e	50	spin_unlock(&wdt_lock);
1da177e4 LT	51	}
1da177e4 LT	52
20d35f3e	53	static void wdt_disable(void)
1da177e4	54	{
20d35f3e	55	spin_lock(&wdt_lock);
1da177e4 LT	56	*IXP4XX_OSWK = IXP4XX_WDT_KEY;
	57	*IXP4XX_OSWE = 0;
	58	*IXP4XX_OSWK = 0;
20d35f3e	59	spin_unlock(&wdt_lock);
1da177e4 LT	60	}
1da177e4 LT	61
20d35f3e	62	static int ixp4xx_wdt_open(struct inode inode, struct file file)
1da177e4 LT	63	{
	64	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	65	return -EBUSY;
	66
	67	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
1da177e4	68	wdt_enable();
c5bf68fe	69	return stream_open(inode, file);
1da177e4 LT	70	}
	71
	72	static ssize_t
	73	ixp4xx_wdt_write(struct file file, const char data, size_t len, loff_t *ppos)
	74	{
	75	if (len) {
	76	if (!nowayout) {
	77	size_t i;
	78
	79	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	80
	81	for (i = 0; i != len; i++) {
	82	char c;
	83
	84	if (get_user(c, data + i))
	85	return -EFAULT;
	86	if (c == 'V')
	87	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	88	}
	89	}
	90	wdt_enable();
	91	}
1da177e4 LT	92	return len;
	93	}
	94
42747d71	95	static const struct watchdog_info ident = {
1da177e4 LT	96	.options = WDIOF_CARDRESET \| WDIOF_MAGICCLOSE \|
	97	WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	98	.identity = "IXP4xx Watchdog",
	99	};
	100
	101
20d35f3e AC	102	static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
20d35f3e AC	103	unsigned long arg)
1da177e4	104	{
795b89d2	105	int ret = -ENOTTY;
1da177e4 LT	106	int time;
	107
	108	switch (cmd) {
	109	case WDIOC_GETSUPPORT:
	110	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	111	sizeof(ident)) ? -EFAULT : 0;
	112	break;
	113
	114	case WDIOC_GETSTATUS:
	115	ret = put_user(0, (int *)arg);
	116	break;
	117
	118	case WDIOC_GETBOOTSTATUS:
	119	ret = put_user(boot_status, (int *)arg);
	120	break;
	121
0c06090c WVS	122	case WDIOC_KEEPALIVE:
	123	wdt_enable();
	124	ret = 0;
	125	break;
	126
1da177e4 LT	127	case WDIOC_SETTIMEOUT:
	128	ret = get_user(time, (int *)arg);
	129	if (ret)
	130	break;
	131
	132	if (time <= 0 \|\| time > 60) {
	133	ret = -EINVAL;
	134	break;
	135	}
	136
	137	heartbeat = time;
	138	wdt_enable();
	139	/* Fall through */
	140
	141	case WDIOC_GETTIMEOUT:
	142	ret = put_user(heartbeat, (int *)arg);
	143	break;
1da177e4 LT	144	}
	145	return ret;
	146	}
	147
20d35f3e	148	static int ixp4xx_wdt_release(struct inode inode, struct file file)
1da177e4	149	{
20d35f3e	150	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
1da177e4	151	wdt_disable();
20d35f3e	152	else
27c766aa	153	pr_crit("Device closed unexpectedly - timer will not stop\n");
1da177e4 LT	154	clear_bit(WDT_IN_USE, &wdt_status);
	155	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	156
	157	return 0;
	158	}
	159
	160
7944d3a5	161	static const struct file_operations ixp4xx_wdt_fops = {
1da177e4 LT	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
7944d3a5	170	static struct miscdevice ixp4xx_wdt_miscdev = {
1da177e4	171	.minor = WATCHDOG_MINOR,
2dab3cab	172	.name = "watchdog",
1da177e4 LT	173	.fops = &ixp4xx_wdt_fops,
	174	};
	175
	176	static int __init ixp4xx_wdt_init(void)
	177	{
	178	int ret;
1da177e4	179
9540724c LW	180	/*
	181	* FIXME: we bail out on device tree boot but this really needs
	182	* to be fixed in a nicer way: this registers the MDIO bus before
	183	* even matching the driver infrastructure, we should only probe
	184	* detected hardware.
	185	*/
	186	if (of_have_populated_dt())
	187	return -ENODEV;
0ba8b9b2	188	if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
27c766aa	189	pr_err("Rev. A0 IXP42x CPU detected - watchdog disabled\n");
1da177e4 LT	190
	191	return -ENODEV;
	192	}
1da177e4 LT	193	boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
1da177e4 LT	194	WDIOF_CARDRESET : 0;
1da177e4 LT	195	ret = misc_register(&ixp4xx_wdt_miscdev);
1da177e4 LT	196	if (ret == 0)
27c766aa	197	pr_info("timer heartbeat %d sec\n", heartbeat);
1da177e4 LT	198	return ret;
	199	}
	200
	201	static void __exit ixp4xx_wdt_exit(void)
	202	{
	203	misc_deregister(&ixp4xx_wdt_miscdev);
	204	}
	205
	206
	207	module_init(ixp4xx_wdt_init);
	208	module_exit(ixp4xx_wdt_exit);
	209
	210	MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
	211	MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
	212
	213	module_param(heartbeat, int, 0);
	214	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
	215
86a1e189	216	module_param(nowayout, bool, 0);
1da177e4 LT	217	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	218
	219	MODULE_LICENSE("GPL");