[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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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/hardware.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 bool 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, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
#endif


static unsigned long ks8695wdt_busy;
static DEFINE_SPINLOCK(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 * KS8695_CLOCK_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 KS8695_CLOCK_RATE / 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 const 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 __devinit 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;

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

static int __devexit 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		= __devexit_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)
{
	/* 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
27c766aa JP	11	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	12
1977f032	13	#include <linux/bitops.h>
ccb8f430 AV	14	#include <linux/errno.h>
	15	#include <linux/fs.h>
	16	#include <linux/init.h>
	17	#include <linux/kernel.h>
	18	#include <linux/miscdevice.h>
	19	#include <linux/module.h>
	20	#include <linux/moduleparam.h>
	21	#include <linux/platform_device.h>
	22	#include <linux/types.h>
	23	#include <linux/watchdog.h>
f4fabce1 AC	24	#include <linux/io.h>
f4fabce1 AC	25	#include <linux/uaccess.h>
568dba66	26	#include <mach/hardware.h>
a09e64fb	27	#include <mach/regs-timer.h>
ccb8f430	28
ccb8f430 AV	29	#define WDT_DEFAULT_TIME 5 /* seconds */
	30	#define WDT_MAX_TIME 171 /* seconds */
	31
	32	static int wdt_time = WDT_DEFAULT_TIME;
86a1e189	33	static bool nowayout = WATCHDOG_NOWAYOUT;
ccb8f430 AV	34
ccb8f430 AV	35	module_param(wdt_time, int, 0);
f4fabce1 AC	36	MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
f4fabce1 AC	37	__MODULE_STRING(WDT_DEFAULT_TIME) ")");
ccb8f430 AV	38
ccb8f430 AV	39	#ifdef CONFIG_WATCHDOG_NOWAYOUT
86a1e189	40	module_param(nowayout, bool, 0);
f4fabce1 AC	41	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
f4fabce1 AC	42	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
ccb8f430 AV	43	#endif
	44
	45
	46	static unsigned long ks8695wdt_busy;
1334f329	47	static DEFINE_SPINLOCK(ks8695_lock);
ccb8f430 AV	48
	49	/* ......................................................................... */
	50
	51	/*
	52	* Disable the watchdog.
	53	*/
f4fabce1	54	static inline void ks8695_wdt_stop(void)
ccb8f430 AV	55	{
	56	unsigned long tmcon;
	57
f4fabce1	58	spin_lock(&ks8695_lock);
ccb8f430 AV	59	/* disable timer0 */
	60	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	61	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
f4fabce1	62	spin_unlock(&ks8695_lock);
ccb8f430 AV	63	}
	64
	65	/*
	66	* Enable and reset the watchdog.
	67	*/
f4fabce1	68	static inline void ks8695_wdt_start(void)
ccb8f430 AV	69	{
ccb8f430 AV	70	unsigned long tmcon;
0a51810a	71	unsigned long tval = wdt_time * KS8695_CLOCK_RATE;
ccb8f430	72
f4fabce1	73	spin_lock(&ks8695_lock);
ccb8f430 AV	74	/* disable timer0 */
	75	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	76	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	77
	78	/* program timer0 */
	79	__raw_writel(tval \| T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
	80
	81	/* re-enable timer0 */
	82	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	83	__raw_writel(tmcon \| TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
f4fabce1	84	spin_unlock(&ks8695_lock);
ccb8f430 AV	85	}
	86
	87	/*
	88	* Reload the watchdog timer. (ie, pat the watchdog)
	89	*/
f4fabce1	90	static inline void ks8695_wdt_reload(void)
ccb8f430 AV	91	{
	92	unsigned long tmcon;
	93
f4fabce1	94	spin_lock(&ks8695_lock);
ccb8f430 AV	95	/* disable, then re-enable timer0 */
	96	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	97	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	98	__raw_writel(tmcon \| TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
f4fabce1	99	spin_unlock(&ks8695_lock);
ccb8f430 AV	100	}
	101
	102	/*
	103	* Change the watchdog time interval.
	104	*/
	105	static int ks8695_wdt_settimeout(int new_time)
	106	{
	107	/*
0a51810a	108	* All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz
ccb8f430 AV	109	*
	110	* Since WDV is a 16-bit counter, the maximum period is
	111	* 65536 / 0.256 = 256 seconds.
	112	*/
	113	if ((new_time <= 0) \|\| (new_time > WDT_MAX_TIME))
	114	return -EINVAL;
	115
f4fabce1 AC	116	/* Set new watchdog time. It will be used when
f4fabce1 AC	117	ks8695_wdt_start() is called. */
ccb8f430 AV	118	wdt_time = new_time;
	119	return 0;
	120	}
	121
	122	/* ......................................................................... */
	123
	124	/*
	125	* Watchdog device is opened, and watchdog starts running.
	126	*/
	127	static int ks8695_wdt_open(struct inode inode, struct file file)
	128	{
	129	if (test_and_set_bit(0, &ks8695wdt_busy))
	130	return -EBUSY;
	131
	132	ks8695_wdt_start();
	133	return nonseekable_open(inode, file);
	134	}
	135
	136	/*
	137	* Close the watchdog device.
	138	* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
	139	* disabled.
	140	*/
	141	static int ks8695_wdt_close(struct inode inode, struct file file)
	142	{
f4fabce1	143	/* Disable the watchdog when file is closed */
ccb8f430	144	if (!nowayout)
f4fabce1	145	ks8695_wdt_stop();
ccb8f430 AV	146	clear_bit(0, &ks8695wdt_busy);
	147	return 0;
	148	}
	149
42747d71	150	static const struct watchdog_info ks8695_wdt_info = {
ccb8f430 AV	151	.identity = "ks8695 watchdog",
	152	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	153	};
	154
	155	/*
	156	* Handle commands from user-space.
	157	*/
f4fabce1 AC	158	static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
f4fabce1 AC	159	unsigned long arg)
ccb8f430 AV	160	{
	161	void __user argp = (void __user )arg;
	162	int __user *p = argp;
	163	int new_value;
	164
f4fabce1	165	switch (cmd) {
f4fabce1 AC	166	case WDIOC_GETSUPPORT:
	167	return copy_to_user(argp, &ks8695_wdt_info,
	168	sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
f4fabce1 AC	169	case WDIOC_GETSTATUS:
	170	case WDIOC_GETBOOTSTATUS:
	171	return put_user(0, p);
	172	case WDIOC_SETOPTIONS:
	173	if (get_user(new_value, p))
	174	return -EFAULT;
	175	if (new_value & WDIOS_DISABLECARD)
	176	ks8695_wdt_stop();
	177	if (new_value & WDIOS_ENABLECARD)
ccb8f430	178	ks8695_wdt_start();
f4fabce1	179	return 0;
0c06090c WVS	180	case WDIOC_KEEPALIVE:
	181	ks8695_wdt_reload(); /* pat the watchdog */
	182	return 0;
	183	case WDIOC_SETTIMEOUT:
	184	if (get_user(new_value, p))
	185	return -EFAULT;
	186	if (ks8695_wdt_settimeout(new_value))
	187	return -EINVAL;
	188	/* Enable new time value */
	189	ks8695_wdt_start();
	190	/* Return current value */
	191	return put_user(wdt_time, p);
	192	case WDIOC_GETTIMEOUT:
	193	return put_user(wdt_time, p);
f4fabce1 AC	194	default:
f4fabce1 AC	195	return -ENOTTY;
ccb8f430 AV	196	}
	197	}
	198
	199	/*
	200	* Pat the watchdog whenever device is written to.
	201	*/
f4fabce1 AC	202	static ssize_t ks8695_wdt_write(struct file file, const char data,
f4fabce1 AC	203	size_t len, loff_t *ppos)
ccb8f430 AV	204	{
	205	ks8695_wdt_reload(); /* pat the watchdog */
	206	return len;
	207	}
	208
	209	/* ......................................................................... */
	210
	211	static const struct file_operations ks8695wdt_fops = {
	212	.owner = THIS_MODULE,
	213	.llseek = no_llseek,
f4fabce1	214	.unlocked_ioctl = ks8695_wdt_ioctl,
ccb8f430 AV	215	.open = ks8695_wdt_open,
	216	.release = ks8695_wdt_close,
	217	.write = ks8695_wdt_write,
	218	};
	219
	220	static struct miscdevice ks8695wdt_miscdev = {
	221	.minor = WATCHDOG_MINOR,
	222	.name = "watchdog",
	223	.fops = &ks8695wdt_fops,
	224	};
	225
c98d58e0	226	static int __devinit ks8695wdt_probe(struct platform_device *pdev)
ccb8f430 AV	227	{
	228	int res;
	229
	230	if (ks8695wdt_miscdev.parent)
	231	return -EBUSY;
	232	ks8695wdt_miscdev.parent = &pdev->dev;
	233
	234	res = misc_register(&ks8695wdt_miscdev);
	235	if (res)
	236	return res;
	237
27c766aa JP	238	pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n",
27c766aa JP	239	wdt_time, nowayout ? ", nowayout" : "");
ccb8f430 AV	240	return 0;
	241	}
	242
c98d58e0	243	static int __devexit ks8695wdt_remove(struct platform_device *pdev)
ccb8f430 AV	244	{
	245	int res;
	246
	247	res = misc_deregister(&ks8695wdt_miscdev);
	248	if (!res)
	249	ks8695wdt_miscdev.parent = NULL;
	250
	251	return res;
	252	}
	253
	254	static void ks8695wdt_shutdown(struct platform_device *pdev)
	255	{
	256	ks8695_wdt_stop();
	257	}
	258
	259	#ifdef CONFIG_PM
	260
	261	static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
	262	{
	263	ks8695_wdt_stop();
	264	return 0;
	265	}
	266
	267	static int ks8695wdt_resume(struct platform_device *pdev)
	268	{
	269	if (ks8695wdt_busy)
	270	ks8695_wdt_start();
	271	return 0;
	272	}
	273
	274	#else
	275	#define ks8695wdt_suspend NULL
	276	#define ks8695wdt_resume NULL
	277	#endif
	278
	279	static struct platform_driver ks8695wdt_driver = {
	280	.probe = ks8695wdt_probe,
c98d58e0	281	.remove = __devexit_p(ks8695wdt_remove),
ccb8f430 AV	282	.shutdown = ks8695wdt_shutdown,
	283	.suspend = ks8695wdt_suspend,
	284	.resume = ks8695wdt_resume,
	285	.driver = {
	286	.name = "ks8695_wdt",
	287	.owner = THIS_MODULE,
	288	},
	289	};
	290
	291	static int __init ks8695_wdt_init(void)
	292	{
f4fabce1 AC	293	/* Check that the heartbeat value is within range;
f4fabce1 AC	294	if not reset to the default */
ccb8f430 AV	295	if (ks8695_wdt_settimeout(wdt_time)) {
ccb8f430 AV	296	ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
a77dba7e WVS	297	pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i"
a77dba7e WVS	298	", using %d\n", wdt_time, WDT_MAX_TIME);
ccb8f430	299	}
ccb8f430 AV	300	return platform_driver_register(&ks8695wdt_driver);
	301	}
	302
	303	static void __exit ks8695_wdt_exit(void)
	304	{
	305	platform_driver_unregister(&ks8695wdt_driver);
	306	}
	307
	308	module_init(ks8695_wdt_init);
	309	module_exit(ks8695_wdt_exit);
	310
	311	MODULE_AUTHOR("Andrew Victor");
	312	MODULE_DESCRIPTION("Watchdog driver for KS8695");
	313	MODULE_LICENSE("GPL");
	314	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
f37d193c	315	MODULE_ALIAS("platform:ks8695_wdt");