[deliverable/linux.git] / drivers / char / watchdog / mpc83xx_wdt.c

/*
 * mpc83xx_wdt.c - MPC83xx watchdog userspace interface
 *
 * Authors: Dave Updegraff <dave@cray.org>
 * 	    Kumar Gala <galak@kernel.crashing.org>
 * 		Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
 * 				..and from sc520_wdt
 *
 * Note: it appears that you can only actually ENABLE or DISABLE the thing
 * once after POR. Once enabled, you cannot disable, and vice versa.
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 */

#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <asm/io.h>
#include <asm/uaccess.h>

struct mpc83xx_wdt {
	__be32 res0;
	__be32 swcrr; /* System watchdog control register */
#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
	__be32 swcnr; /* System watchdog count register */
	u8 res1[2];
	__be16 swsrr; /* System watchdog service register */
	u8 res2[0xF0];
};

static struct mpc83xx_wdt __iomem *wd_base;

static u16 timeout = 0xffff;
module_param(timeout, ushort, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in ticks. (0<timeout<65536, default=65535");

static int reset = 1;
module_param(reset, bool, 0);
MODULE_PARM_DESC(reset, "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");

/*
 * We always prescale, but if someone really doesn't want to they can set this
 * to 0
 */
static int prescale = 1;
static unsigned int timeout_sec;

static unsigned long wdt_is_open;
static spinlock_t wdt_spinlock;

static void mpc83xx_wdt_keepalive(void)
{
	/* Ping the WDT */
	spin_lock(&wdt_spinlock);
	out_be16(&wd_base->swsrr, 0x556c);
	out_be16(&wd_base->swsrr, 0xaa39);
	spin_unlock(&wdt_spinlock);
}

static ssize_t mpc83xx_wdt_write(struct file *file, const char __user *buf,
				 size_t count, loff_t *ppos)
{
	if (count)
		mpc83xx_wdt_keepalive();
	return count;
}

static int mpc83xx_wdt_open(struct inode *inode, struct file *file)
{
	u32 tmp = SWCRR_SWEN;
	if (test_and_set_bit(0, &wdt_is_open))
		return -EBUSY;

	/* Once we start the watchdog we can't stop it */
	__module_get(THIS_MODULE);

	/* Good, fire up the show */
	if (prescale)
		tmp |= SWCRR_SWPR;
	if (reset)
		tmp |= SWCRR_SWRI;

	tmp |= timeout << 16;

	out_be32(&wd_base->swcrr, tmp);

	return nonseekable_open(inode, file);
}

static int mpc83xx_wdt_release(struct inode *inode, struct file *file)
{
	printk(KERN_CRIT "Unexpected close, not stopping watchdog!\n");
	mpc83xx_wdt_keepalive();
	clear_bit(0, &wdt_is_open);
	return 0;
}

static int mpc83xx_wdt_ioctl(struct inode *inode, struct file *file,
				unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static struct watchdog_info ident = {
		.options = WDIOF_KEEPALIVEPING,
		.firmware_version = 1,
		.identity = "MPC83xx",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	case WDIOC_KEEPALIVE:
		mpc83xx_wdt_keepalive();
		return 0;
	case WDIOC_GETTIMEOUT:
		return put_user(timeout_sec, p);
	default:
		return -ENOIOCTLCMD;
	}
}

static const struct file_operations mpc83xx_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= mpc83xx_wdt_write,
	.ioctl		= mpc83xx_wdt_ioctl,
	.open		= mpc83xx_wdt_open,
	.release	= mpc83xx_wdt_release,
};

static struct miscdevice mpc83xx_wdt_miscdev = {
	.minor	= WATCHDOG_MINOR,
	.name	= "watchdog",
	.fops	= &mpc83xx_wdt_fops,
};

static int __devinit mpc83xx_wdt_probe(struct platform_device *dev)
{
	struct resource *r;
	int ret;
	unsigned int *freq = dev->dev.platform_data;

	/* get a pointer to the register memory */
	r = platform_get_resource(dev, IORESOURCE_MEM, 0);

	if (!r) {
		ret = -ENODEV;
		goto err_out;
	}

	wd_base = ioremap(r->start, sizeof (struct mpc83xx_wdt));

	if (wd_base == NULL) {
		ret = -ENOMEM;
		goto err_out;
	}

	ret = misc_register(&mpc83xx_wdt_miscdev);
	if (ret) {
		printk(KERN_ERR "cannot register miscdev on minor=%d "
				"(err=%d)\n",
				WATCHDOG_MINOR, ret);
		goto err_unmap;
	}

	/* Calculate the timeout in seconds */
	if (prescale)
		timeout_sec = (timeout * 0x10000) / (*freq);
	else
		timeout_sec = timeout / (*freq);

	printk(KERN_INFO "WDT driver for MPC83xx initialized. "
		"mode:%s timeout=%d (%d seconds)\n",
		reset ? "reset":"interrupt", timeout, timeout_sec);

	spin_lock_init(&wdt_spinlock);

	return 0;

err_unmap:
	iounmap(wd_base);
err_out:
	return ret;
}

static int __devexit mpc83xx_wdt_remove(struct platform_device *dev)
{
	misc_deregister(&mpc83xx_wdt_miscdev);
	iounmap(wd_base);

	return 0;
}

static struct platform_driver mpc83xx_wdt_driver = {
	.probe		= mpc83xx_wdt_probe,
	.remove		= __devexit_p(mpc83xx_wdt_remove),
	.driver		= {
		.name	= "mpc83xx_wdt",
	},
};

static int __init mpc83xx_wdt_init(void)
{
	return platform_driver_register(&mpc83xx_wdt_driver);
}

static void __exit mpc83xx_wdt_exit(void)
{
	platform_driver_unregister(&mpc83xx_wdt_driver);
}

module_init(mpc83xx_wdt_init);
module_exit(mpc83xx_wdt_exit);

MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
MODULE_DESCRIPTION("Driver for watchdog timer in MPC83xx uProcessor");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
fabbfb9e KG	1	/*
	2	* mpc83xx_wdt.c - MPC83xx watchdog userspace interface
	3	*
	4	* Authors: Dave Updegraff <dave@cray.org>
	5	* Kumar Gala <galak@kernel.crashing.org>
	6	* Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
	7	* ..and from sc520_wdt
	8	*
	9	* Note: it appears that you can only actually ENABLE or DISABLE the thing
	10	* once after POR. Once enabled, you cannot disable, and vice versa.
	11	*
	12	* This program is free software; you can redistribute it and/or modify it
	13	* under the terms of the GNU General Public License as published by the
	14	* Free Software Foundation; either version 2 of the License, or (at your
	15	* option) any later version.
	16	*/
	17
fabbfb9e KG	18	#include <linux/fs.h>
	19	#include <linux/init.h>
	20	#include <linux/kernel.h>
	21	#include <linux/miscdevice.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/module.h>
	24	#include <linux/watchdog.h>
	25	#include <asm/io.h>
	26	#include <asm/uaccess.h>
	27
	28	struct mpc83xx_wdt {
	29	__be32 res0;
	30	__be32 swcrr; /* System watchdog control register */
	31	#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
	32	#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
	33	#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
	34	#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
	35	__be32 swcnr; /* System watchdog count register */
	36	u8 res1[2];
	37	__be16 swsrr; /* System watchdog service register */
	38	u8 res2[0xF0];
	39	};
	40
	41	static struct mpc83xx_wdt __iomem *wd_base;
	42
	43	static u16 timeout = 0xffff;
	44	module_param(timeout, ushort, 0);
	45	MODULE_PARM_DESC(timeout, "Watchdog timeout in ticks. (0<timeout<65536, default=65535");
	46
	47	static int reset = 1;
	48	module_param(reset, bool, 0);
	49	MODULE_PARM_DESC(reset, "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
	50
	51	/*
	52	* We always prescale, but if someone really doesn't want to they can set this
	53	* to 0
	54	*/
	55	static int prescale = 1;
	56	static unsigned int timeout_sec;
	57
	58	static unsigned long wdt_is_open;
	59	static spinlock_t wdt_spinlock;
	60
	61	static void mpc83xx_wdt_keepalive(void)
	62	{
	63	/* Ping the WDT */
	64	spin_lock(&wdt_spinlock);
	65	out_be16(&wd_base->swsrr, 0x556c);
	66	out_be16(&wd_base->swsrr, 0xaa39);
	67	spin_unlock(&wdt_spinlock);
	68	}
	69
	70	static ssize_t mpc83xx_wdt_write(struct file file, const char __user buf,
	71	size_t count, loff_t *ppos)
	72	{
	73	if (count)
	74	mpc83xx_wdt_keepalive();
	75	return count;
	76	}
	77
	78	static int mpc83xx_wdt_open(struct inode inode, struct file file)
	79	{
	80	u32 tmp = SWCRR_SWEN;
	81	if (test_and_set_bit(0, &wdt_is_open))
82	return -EBUSY;
83
84	/* Once we start the watchdog we can't stop it */
85	__module_get(THIS_MODULE);
86
87	/* Good, fire up the show */
88	if (prescale)
89	tmp \|= SWCRR_SWPR;
90	if (reset)
91	tmp \|= SWCRR_SWRI;
92
93	tmp \|= timeout << 16;
94
95	out_be32(&wd_base->swcrr, tmp);
96
97	return nonseekable_open(inode, file);
98	}
99
100	static int mpc83xx_wdt_release(struct inode inode, struct file file)
101	{
102	printk(KERN_CRIT "Unexpected close, not stopping watchdog!\n");
103	mpc83xx_wdt_keepalive();
104	clear_bit(0, &wdt_is_open);
105	return 0;
106	}
107
108	static int mpc83xx_wdt_ioctl(struct inode inode, struct file file,
109	unsigned int cmd, unsigned long arg)
110	{
111	void __user argp = (void __user )arg;
112	int __user *p = argp;
113	static struct watchdog_info ident = {
114	.options = WDIOF_KEEPALIVEPING,
115	.firmware_version = 1,
116	.identity = "MPC83xx",
117	};
118
119	switch (cmd) {
120	case WDIOC_GETSUPPORT:
121	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
122	case WDIOC_KEEPALIVE:
123	mpc83xx_wdt_keepalive();
124	return 0;
125	case WDIOC_GETTIMEOUT:
126	return put_user(timeout_sec, p);
127	default:
128	return -ENOIOCTLCMD;
129	}
130	}
131
62322d25	132	static const struct file_operations mpc83xx_wdt_fops = {
fabbfb9e KG	133	.owner = THIS_MODULE,
	134	.llseek = no_llseek,
	135	.write = mpc83xx_wdt_write,
	136	.ioctl = mpc83xx_wdt_ioctl,
	137	.open = mpc83xx_wdt_open,
	138	.release = mpc83xx_wdt_release,
	139	};
	140
	141	static struct miscdevice mpc83xx_wdt_miscdev = {
	142	.minor = WATCHDOG_MINOR,
	143	.name = "watchdog",
	144	.fops = &mpc83xx_wdt_fops,
	145	};
	146
	147	static int __devinit mpc83xx_wdt_probe(struct platform_device *dev)
	148	{
	149	struct resource *r;
	150	int ret;
	151	unsigned int *freq = dev->dev.platform_data;
	152
	153	/* get a pointer to the register memory */
	154	r = platform_get_resource(dev, IORESOURCE_MEM, 0);
	155
	156	if (!r) {
	157	ret = -ENODEV;
	158	goto err_out;
	159	}
	160
	161	wd_base = ioremap(r->start, sizeof (struct mpc83xx_wdt));
	162
	163	if (wd_base == NULL) {
	164	ret = -ENOMEM;
	165	goto err_out;
	166	}
	167
	168	ret = misc_register(&mpc83xx_wdt_miscdev);
	169	if (ret) {
	170	printk(KERN_ERR "cannot register miscdev on minor=%d "
	171	"(err=%d)\n",
	172	WATCHDOG_MINOR, ret);
	173	goto err_unmap;
	174	}
	175
	176	/* Calculate the timeout in seconds */
	177	if (prescale)
	178	timeout_sec = (timeout * 0x10000) / (*freq);
	179	else
	180	timeout_sec = timeout / (*freq);
	181
	182	printk(KERN_INFO "WDT driver for MPC83xx initialized. "
	183	"mode:%s timeout=%d (%d seconds)\n",
	184	reset ? "reset":"interrupt", timeout, timeout_sec);
	185
	186	spin_lock_init(&wdt_spinlock);
	187
	188	return 0;
	189
	190	err_unmap:
	191	iounmap(wd_base);
	192	err_out:
	193	return ret;
	194	}
	195
	196	static int __devexit mpc83xx_wdt_remove(struct platform_device *dev)
197	{
198	misc_deregister(&mpc83xx_wdt_miscdev);
199	iounmap(wd_base);
200
201	return 0;
202	}
203
204	static struct platform_driver mpc83xx_wdt_driver = {
205	.probe = mpc83xx_wdt_probe,
206	.remove = __devexit_p(mpc83xx_wdt_remove),
207	.driver = {
208	.name = "mpc83xx_wdt",
209	},
210	};
211
212	static int __init mpc83xx_wdt_init(void)
213	{
214	return platform_driver_register(&mpc83xx_wdt_driver);
215	}
216
217	static void __exit mpc83xx_wdt_exit(void)
218	{
219	platform_driver_unregister(&mpc83xx_wdt_driver);
220	}
221
222	module_init(mpc83xx_wdt_init);
223	module_exit(mpc83xx_wdt_exit);
224
225	MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
226	MODULE_DESCRIPTION("Driver for watchdog timer in MPC83xx uProcessor");
227	MODULE_LICENSE("GPL");
228	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);