[deliverable/linux.git] / drivers / watchdog / ks8695_wdt.c

/*
 * Watchdog driver for Kendin/Micrel KS8695.
 *
 * (C) 2007 Andrew Victor
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <mach/regs-timer.h>

#define WDT_DEFAULT_TIME	5	/* seconds */
#define WDT_MAX_TIME		171	/* seconds */

static int wdt_time = WDT_DEFAULT_TIME;
static int nowayout = WATCHDOG_NOWAYOUT;

module_param(wdt_time, int, 0);
MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
					__MODULE_STRING(WDT_DEFAULT_TIME) ")");

#ifdef CONFIG_WATCHDOG_NOWAYOUT
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
#endif


static unsigned long ks8695wdt_busy;
static spinlock_t ks8695_lock;

/* ......................................................................... */

/*
 * Disable the watchdog.
 */
static inline void ks8695_wdt_stop(void)
{
	unsigned long tmcon;

	spin_lock(&ks8695_lock);
	/* disable timer0 */
	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	spin_unlock(&ks8695_lock);
}

/*
 * Enable and reset the watchdog.
 */
static inline void ks8695_wdt_start(void)
{
	unsigned long tmcon;
	unsigned long tval = wdt_time * CLOCK_TICK_RATE;

	spin_lock(&ks8695_lock);
	/* disable timer0 */
	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);

	/* program timer0 */
	__raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);

	/* re-enable timer0 */
	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	__raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	spin_unlock(&ks8695_lock);
}

/*
 * Reload the watchdog timer.  (ie, pat the watchdog)
 */
static inline void ks8695_wdt_reload(void)
{
	unsigned long tmcon;

	spin_lock(&ks8695_lock);
	/* disable, then re-enable timer0 */
	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	__raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	spin_unlock(&ks8695_lock);
}

/*
 * Change the watchdog time interval.
 */
static int ks8695_wdt_settimeout(int new_time)
{
	/*
	 * All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
	 *
	 * Since WDV is a 16-bit counter, the maximum period is
	 * 65536 / 0.256 = 256 seconds.
	 */
	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
		return -EINVAL;

	/* Set new watchdog time. It will be used when
	   ks8695_wdt_start() is called. */
	wdt_time = new_time;
	return 0;
}

/* ......................................................................... */

/*
 * Watchdog device is opened, and watchdog starts running.
 */
static int ks8695_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &ks8695wdt_busy))
		return -EBUSY;

	ks8695_wdt_start();
	return nonseekable_open(inode, file);
}

/*
 * Close the watchdog device.
 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
 *  disabled.
 */
static int ks8695_wdt_close(struct inode *inode, struct file *file)
{
	/* Disable the watchdog when file is closed */
	if (!nowayout)
		ks8695_wdt_stop();
	clear_bit(0, &ks8695wdt_busy);
	return 0;
}

static struct watchdog_info ks8695_wdt_info = {
	.identity	= "ks8695 watchdog",
	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
};

/*
 * Handle commands from user-space.
 */
static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_value;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ks8695_wdt_info,
					sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);
	case WDIOC_SETOPTIONS:
		if (get_user(new_value, p))
			return -EFAULT;
		if (new_value & WDIOS_DISABLECARD)
			ks8695_wdt_stop();
		if (new_value & WDIOS_ENABLECARD)
			ks8695_wdt_start();
		return 0;
	case WDIOC_KEEPALIVE:
		ks8695_wdt_reload();	/* pat the watchdog */
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_value, p))
			return -EFAULT;
		if (ks8695_wdt_settimeout(new_value))
			return -EINVAL;
		/* Enable new time value */
		ks8695_wdt_start();
		/* Return current value */
		return put_user(wdt_time, p);
	case WDIOC_GETTIMEOUT:
		return put_user(wdt_time, p);
	default:
		return -ENOTTY;
	}
}

/*
 * Pat the watchdog whenever device is written to.
 */
static ssize_t ks8695_wdt_write(struct file *file, const char *data,
						size_t len, loff_t *ppos)
{
	ks8695_wdt_reload();		/* pat the watchdog */
	return len;
}

/* ......................................................................... */

static const struct file_operations ks8695wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.unlocked_ioctl	= ks8695_wdt_ioctl,
	.open		= ks8695_wdt_open,
	.release	= ks8695_wdt_close,
	.write		= ks8695_wdt_write,
};

static struct miscdevice ks8695wdt_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &ks8695wdt_fops,
};

static int __init ks8695wdt_probe(struct platform_device *pdev)
{
	int res;

	if (ks8695wdt_miscdev.parent)
		return -EBUSY;
	ks8695wdt_miscdev.parent = &pdev->dev;

	res = misc_register(&ks8695wdt_miscdev);
	if (res)
		return res;

	printk(KERN_INFO "KS8695 Watchdog Timer enabled (%d seconds%s)\n",
				wdt_time, nowayout ? ", nowayout" : "");
	return 0;
}

static int __exit ks8695wdt_remove(struct platform_device *pdev)
{
	int res;

	res = misc_deregister(&ks8695wdt_miscdev);
	if (!res)
		ks8695wdt_miscdev.parent = NULL;

	return res;
}

static void ks8695wdt_shutdown(struct platform_device *pdev)
{
	ks8695_wdt_stop();
}

#ifdef CONFIG_PM

static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
{
	ks8695_wdt_stop();
	return 0;
}

static int ks8695wdt_resume(struct platform_device *pdev)
{
	if (ks8695wdt_busy)
		ks8695_wdt_start();
	return 0;
}

#else
#define ks8695wdt_suspend NULL
#define ks8695wdt_resume	NULL
#endif

static struct platform_driver ks8695wdt_driver = {
	.probe		= ks8695wdt_probe,
	.remove		= __exit_p(ks8695wdt_remove),
	.shutdown	= ks8695wdt_shutdown,
	.suspend	= ks8695wdt_suspend,
	.resume		= ks8695wdt_resume,
	.driver		= {
		.name	= "ks8695_wdt",
		.owner	= THIS_MODULE,
	},
};

static int __init ks8695_wdt_init(void)
{
	spin_lock_init(&ks8695_lock);
	/* Check that the heartbeat value is within range;
	   if not reset to the default */
	if (ks8695_wdt_settimeout(wdt_time)) {
		ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
		pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i, using %d\n",
							wdt_time, WDT_MAX_TIME);
	}
	return platform_driver_register(&ks8695wdt_driver);
}

static void __exit ks8695_wdt_exit(void)
{
	platform_driver_unregister(&ks8695wdt_driver);
}

module_init(ks8695_wdt_init);
module_exit(ks8695_wdt_exit);

MODULE_AUTHOR("Andrew Victor");
MODULE_DESCRIPTION("Watchdog driver for KS8695");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:ks8695_wdt");
Commit	Line	Data
ccb8f430 AV	1	/*
	2	* Watchdog driver for Kendin/Micrel KS8695.
	3	*
	4	* (C) 2007 Andrew Victor
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*/
	10
1977f032	11	#include <linux/bitops.h>
ccb8f430 AV	12	#include <linux/errno.h>
	13	#include <linux/fs.h>
	14	#include <linux/init.h>
	15	#include <linux/kernel.h>
	16	#include <linux/miscdevice.h>
	17	#include <linux/module.h>
	18	#include <linux/moduleparam.h>
	19	#include <linux/platform_device.h>
	20	#include <linux/types.h>
	21	#include <linux/watchdog.h>
f4fabce1 AC	22	#include <linux/io.h>
f4fabce1 AC	23	#include <linux/uaccess.h>
a09e64fb	24	#include <mach/regs-timer.h>
ccb8f430	25
ccb8f430 AV	26	#define WDT_DEFAULT_TIME 5 /* seconds */
	27	#define WDT_MAX_TIME 171 /* seconds */
	28
	29	static int wdt_time = WDT_DEFAULT_TIME;
	30	static int nowayout = WATCHDOG_NOWAYOUT;
	31
	32	module_param(wdt_time, int, 0);
f4fabce1 AC	33	MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
f4fabce1 AC	34	__MODULE_STRING(WDT_DEFAULT_TIME) ")");
ccb8f430 AV	35
	36	#ifdef CONFIG_WATCHDOG_NOWAYOUT
	37	module_param(nowayout, int, 0);
f4fabce1 AC	38	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
f4fabce1 AC	39	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
ccb8f430 AV	40	#endif
	41
	42
	43	static unsigned long ks8695wdt_busy;
f4fabce1	44	static spinlock_t ks8695_lock;
ccb8f430 AV	45
	46	/* ......................................................................... */
	47
	48	/*
	49	* Disable the watchdog.
	50	*/
f4fabce1	51	static inline void ks8695_wdt_stop(void)
ccb8f430 AV	52	{
	53	unsigned long tmcon;
	54
f4fabce1	55	spin_lock(&ks8695_lock);
ccb8f430 AV	56	/* disable timer0 */
	57	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	58	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
f4fabce1	59	spin_unlock(&ks8695_lock);
ccb8f430 AV	60	}
	61
	62	/*
	63	* Enable and reset the watchdog.
	64	*/
f4fabce1	65	static inline void ks8695_wdt_start(void)
ccb8f430 AV	66	{
	67	unsigned long tmcon;
	68	unsigned long tval = wdt_time * CLOCK_TICK_RATE;
	69
f4fabce1	70	spin_lock(&ks8695_lock);
ccb8f430 AV	71	/* disable timer0 */
	72	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	73	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	74
	75	/* program timer0 */
	76	__raw_writel(tval \| T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
	77
	78	/* re-enable timer0 */
	79	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	80	__raw_writel(tmcon \| TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
f4fabce1	81	spin_unlock(&ks8695_lock);
ccb8f430 AV	82	}
	83
	84	/*
	85	* Reload the watchdog timer. (ie, pat the watchdog)
	86	*/
f4fabce1	87	static inline void ks8695_wdt_reload(void)
ccb8f430 AV	88	{
	89	unsigned long tmcon;
	90
f4fabce1	91	spin_lock(&ks8695_lock);
ccb8f430 AV	92	/* disable, then re-enable timer0 */
	93	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	94	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	95	__raw_writel(tmcon \| TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
f4fabce1	96	spin_unlock(&ks8695_lock);
ccb8f430 AV	97	}
	98
	99	/*
	100	* Change the watchdog time interval.
	101	*/
	102	static int ks8695_wdt_settimeout(int new_time)
	103	{
	104	/*
	105	* All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
	106	*
	107	* Since WDV is a 16-bit counter, the maximum period is
	108	* 65536 / 0.256 = 256 seconds.
	109	*/
	110	if ((new_time <= 0) \|\| (new_time > WDT_MAX_TIME))
	111	return -EINVAL;
	112
f4fabce1 AC	113	/* Set new watchdog time. It will be used when
f4fabce1 AC	114	ks8695_wdt_start() is called. */
ccb8f430 AV	115	wdt_time = new_time;
	116	return 0;
	117	}
	118
	119	/* ......................................................................... */
	120
	121	/*
	122	* Watchdog device is opened, and watchdog starts running.
	123	*/
	124	static int ks8695_wdt_open(struct inode inode, struct file file)
	125	{
	126	if (test_and_set_bit(0, &ks8695wdt_busy))
	127	return -EBUSY;
	128
	129	ks8695_wdt_start();
	130	return nonseekable_open(inode, file);
	131	}
	132
	133	/*
	134	* Close the watchdog device.
	135	* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
	136	* disabled.
	137	*/
	138	static int ks8695_wdt_close(struct inode inode, struct file file)
	139	{
f4fabce1	140	/* Disable the watchdog when file is closed */
ccb8f430	141	if (!nowayout)
f4fabce1	142	ks8695_wdt_stop();
ccb8f430 AV	143	clear_bit(0, &ks8695wdt_busy);
	144	return 0;
	145	}
	146
	147	static struct watchdog_info ks8695_wdt_info = {
	148	.identity = "ks8695 watchdog",
	149	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	150	};
	151
	152	/*
	153	* Handle commands from user-space.
	154	*/
f4fabce1 AC	155	static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
f4fabce1 AC	156	unsigned long arg)
ccb8f430 AV	157	{
	158	void __user argp = (void __user )arg;
	159	int __user *p = argp;
	160	int new_value;
	161
f4fabce1	162	switch (cmd) {
f4fabce1 AC	163	case WDIOC_GETSUPPORT:
	164	return copy_to_user(argp, &ks8695_wdt_info,
	165	sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
f4fabce1 AC	166	case WDIOC_GETSTATUS:
	167	case WDIOC_GETBOOTSTATUS:
	168	return put_user(0, p);
	169	case WDIOC_SETOPTIONS:
	170	if (get_user(new_value, p))
	171	return -EFAULT;
	172	if (new_value & WDIOS_DISABLECARD)
	173	ks8695_wdt_stop();
	174	if (new_value & WDIOS_ENABLECARD)
ccb8f430	175	ks8695_wdt_start();
f4fabce1	176	return 0;
0c06090c WVS	177	case WDIOC_KEEPALIVE:
	178	ks8695_wdt_reload(); /* pat the watchdog */
	179	return 0;
	180	case WDIOC_SETTIMEOUT:
	181	if (get_user(new_value, p))
	182	return -EFAULT;
	183	if (ks8695_wdt_settimeout(new_value))
	184	return -EINVAL;
	185	/* Enable new time value */
	186	ks8695_wdt_start();
	187	/* Return current value */
	188	return put_user(wdt_time, p);
	189	case WDIOC_GETTIMEOUT:
	190	return put_user(wdt_time, p);
f4fabce1 AC	191	default:
f4fabce1 AC	192	return -ENOTTY;
ccb8f430 AV	193	}
	194	}
	195
	196	/*
	197	* Pat the watchdog whenever device is written to.
	198	*/
f4fabce1 AC	199	static ssize_t ks8695_wdt_write(struct file file, const char data,
f4fabce1 AC	200	size_t len, loff_t *ppos)
ccb8f430 AV	201	{
	202	ks8695_wdt_reload(); /* pat the watchdog */
	203	return len;
	204	}
	205
	206	/* ......................................................................... */
	207
	208	static const struct file_operations ks8695wdt_fops = {
	209	.owner = THIS_MODULE,
	210	.llseek = no_llseek,
f4fabce1	211	.unlocked_ioctl = ks8695_wdt_ioctl,
ccb8f430 AV	212	.open = ks8695_wdt_open,
	213	.release = ks8695_wdt_close,
	214	.write = ks8695_wdt_write,
	215	};
	216
	217	static struct miscdevice ks8695wdt_miscdev = {
	218	.minor = WATCHDOG_MINOR,
	219	.name = "watchdog",
	220	.fops = &ks8695wdt_fops,
	221	};
	222
	223	static int __init ks8695wdt_probe(struct platform_device *pdev)
	224	{
	225	int res;
	226
	227	if (ks8695wdt_miscdev.parent)
	228	return -EBUSY;
	229	ks8695wdt_miscdev.parent = &pdev->dev;
	230
	231	res = misc_register(&ks8695wdt_miscdev);
	232	if (res)
	233	return res;
	234
f4fabce1 AC	235	printk(KERN_INFO "KS8695 Watchdog Timer enabled (%d seconds%s)\n",
f4fabce1 AC	236	wdt_time, nowayout ? ", nowayout" : "");
ccb8f430 AV	237	return 0;
	238	}
	239
	240	static int __exit ks8695wdt_remove(struct platform_device *pdev)
	241	{
	242	int res;
	243
	244	res = misc_deregister(&ks8695wdt_miscdev);
	245	if (!res)
	246	ks8695wdt_miscdev.parent = NULL;
	247
	248	return res;
	249	}
	250
	251	static void ks8695wdt_shutdown(struct platform_device *pdev)
	252	{
	253	ks8695_wdt_stop();
	254	}
	255
	256	#ifdef CONFIG_PM
	257
	258	static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
	259	{
	260	ks8695_wdt_stop();
	261	return 0;
	262	}
	263
	264	static int ks8695wdt_resume(struct platform_device *pdev)
	265	{
	266	if (ks8695wdt_busy)
	267	ks8695_wdt_start();
	268	return 0;
	269	}
	270
	271	#else
	272	#define ks8695wdt_suspend NULL
	273	#define ks8695wdt_resume NULL
	274	#endif
	275
	276	static struct platform_driver ks8695wdt_driver = {
	277	.probe = ks8695wdt_probe,
	278	.remove = __exit_p(ks8695wdt_remove),
	279	.shutdown = ks8695wdt_shutdown,
	280	.suspend = ks8695wdt_suspend,
	281	.resume = ks8695wdt_resume,
	282	.driver = {
	283	.name = "ks8695_wdt",
	284	.owner = THIS_MODULE,
	285	},
	286	};
	287
	288	static int __init ks8695_wdt_init(void)
	289	{
f4fabce1 AC	290	spin_lock_init(&ks8695_lock);
	291	/* Check that the heartbeat value is within range;
	292	if not reset to the default */
ccb8f430 AV	293	if (ks8695_wdt_settimeout(wdt_time)) {
ccb8f430 AV	294	ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
f4fabce1 AC	295	pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i, using %d\n",
f4fabce1 AC	296	wdt_time, WDT_MAX_TIME);
ccb8f430	297	}
ccb8f430 AV	298	return platform_driver_register(&ks8695wdt_driver);
	299	}
	300
	301	static void __exit ks8695_wdt_exit(void)
	302	{
	303	platform_driver_unregister(&ks8695wdt_driver);
	304	}
	305
	306	module_init(ks8695_wdt_init);
	307	module_exit(ks8695_wdt_exit);
	308
	309	MODULE_AUTHOR("Andrew Victor");
	310	MODULE_DESCRIPTION("Watchdog driver for KS8695");
	311	MODULE_LICENSE("GPL");
	312	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
f37d193c	313	MODULE_ALIAS("platform:ks8695_wdt");