[linux-2.6-block.git] / drivers / watchdog / ks8695_wdt.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Watchdog driver for Kendin/Micrel KS8695.
 *
 * (C) 2007 Andrew Victor
 */

#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>

#define KS8695_TMR_OFFSET	(0xF0000 + 0xE400)
#define KS8695_TMR_VA		(KS8695_IO_VA + KS8695_TMR_OFFSET)

/*
 * Timer registers
 */
#define KS8695_TMCON		(0x00)		/* Timer Control Register */
#define KS8695_T0TC		(0x08)		/* Timer 0 Timeout Count Register */
#define TMCON_T0EN		(1 << 0)	/* Timer 0 Enable */

/* Timer0 Timeout Counter Register */
#define T0TC_WATCHDOG		(0xff)		/* Enable watchdog mode */

#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 stream_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 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 ks8695wdt_remove(struct platform_device *pdev)
{
	misc_deregister(&ks8695wdt_miscdev);
	ks8695wdt_miscdev.parent = NULL;

	return 0;
}

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		= ks8695wdt_remove,
	.shutdown	= ks8695wdt_shutdown,
	.suspend	= ks8695wdt_suspend,
	.resume		= ks8695wdt_resume,
	.driver		= {
		.name	= "ks8695_wdt",
	},
};

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("platform:ks8695_wdt");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
ccb8f430 AV	2	/*
	3	* Watchdog driver for Kendin/Micrel KS8695.
	4	*
	5	* (C) 2007 Andrew Victor
ccb8f430 AV	6	*/
ccb8f430 AV	7
27c766aa JP	8	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	9
1977f032	10	#include <linux/bitops.h>
ccb8f430 AV	11	#include <linux/errno.h>
	12	#include <linux/fs.h>
	13	#include <linux/init.h>
	14	#include <linux/kernel.h>
	15	#include <linux/miscdevice.h>
	16	#include <linux/module.h>
	17	#include <linux/moduleparam.h>
	18	#include <linux/platform_device.h>
	19	#include <linux/types.h>
	20	#include <linux/watchdog.h>
f4fabce1 AC	21	#include <linux/io.h>
f4fabce1 AC	22	#include <linux/uaccess.h>
568dba66	23	#include <mach/hardware.h>
cab463a2 LW	24
	25	#define KS8695_TMR_OFFSET (0xF0000 + 0xE400)
	26	#define KS8695_TMR_VA (KS8695_IO_VA + KS8695_TMR_OFFSET)
	27
	28	/*
	29	* Timer registers
	30	*/
	31	#define KS8695_TMCON (0x00) /* Timer Control Register */
	32	#define KS8695_T0TC (0x08) /* Timer 0 Timeout Count Register */
	33	#define TMCON_T0EN (1 << 0) /* Timer 0 Enable */
	34
	35	/* Timer0 Timeout Counter Register */
	36	#define T0TC_WATCHDOG (0xff) /* Enable watchdog mode */
ccb8f430	37
ccb8f430 AV	38	#define WDT_DEFAULT_TIME 5 /* seconds */
	39	#define WDT_MAX_TIME 171 /* seconds */
	40
	41	static int wdt_time = WDT_DEFAULT_TIME;
86a1e189	42	static bool nowayout = WATCHDOG_NOWAYOUT;
ccb8f430 AV	43
ccb8f430 AV	44	module_param(wdt_time, int, 0);
f4fabce1 AC	45	MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
f4fabce1 AC	46	__MODULE_STRING(WDT_DEFAULT_TIME) ")");
ccb8f430 AV	47
ccb8f430 AV	48	#ifdef CONFIG_WATCHDOG_NOWAYOUT
86a1e189	49	module_param(nowayout, bool, 0);
f4fabce1 AC	50	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
f4fabce1 AC	51	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
ccb8f430 AV	52	#endif
	53
	54
	55	static unsigned long ks8695wdt_busy;
1334f329	56	static DEFINE_SPINLOCK(ks8695_lock);
ccb8f430 AV	57
	58	/* ......................................................................... */
	59
	60	/*
	61	* Disable the watchdog.
	62	*/
f4fabce1	63	static inline void ks8695_wdt_stop(void)
ccb8f430 AV	64	{
	65	unsigned long tmcon;
	66
f4fabce1	67	spin_lock(&ks8695_lock);
ccb8f430 AV	68	/* disable timer0 */
	69	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	70	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
f4fabce1	71	spin_unlock(&ks8695_lock);
ccb8f430 AV	72	}
	73
	74	/*
	75	* Enable and reset the watchdog.
	76	*/
f4fabce1	77	static inline void ks8695_wdt_start(void)
ccb8f430 AV	78	{
ccb8f430 AV	79	unsigned long tmcon;
0a51810a	80	unsigned long tval = wdt_time * KS8695_CLOCK_RATE;
ccb8f430	81
f4fabce1	82	spin_lock(&ks8695_lock);
ccb8f430 AV	83	/* disable timer0 */
	84	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	85	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	86
	87	/* program timer0 */
	88	__raw_writel(tval \| T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
	89
	90	/* re-enable timer0 */
	91	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	92	__raw_writel(tmcon \| TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
f4fabce1	93	spin_unlock(&ks8695_lock);
ccb8f430 AV	94	}
	95
	96	/*
	97	* Reload the watchdog timer. (ie, pat the watchdog)
	98	*/
f4fabce1	99	static inline void ks8695_wdt_reload(void)
ccb8f430 AV	100	{
	101	unsigned long tmcon;
	102
f4fabce1	103	spin_lock(&ks8695_lock);
ccb8f430 AV	104	/* disable, then re-enable timer0 */
	105	tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
	106	__raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
	107	__raw_writel(tmcon \| TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
f4fabce1	108	spin_unlock(&ks8695_lock);
ccb8f430 AV	109	}
	110
	111	/*
	112	* Change the watchdog time interval.
	113	*/
	114	static int ks8695_wdt_settimeout(int new_time)
	115	{
	116	/*
0a51810a	117	* All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz
ccb8f430 AV	118	*
	119	* Since WDV is a 16-bit counter, the maximum period is
	120	* 65536 / 0.256 = 256 seconds.
	121	*/
	122	if ((new_time <= 0) \|\| (new_time > WDT_MAX_TIME))
	123	return -EINVAL;
	124
f4fabce1 AC	125	/* Set new watchdog time. It will be used when
f4fabce1 AC	126	ks8695_wdt_start() is called. */
ccb8f430 AV	127	wdt_time = new_time;
	128	return 0;
	129	}
	130
	131	/* ......................................................................... */
	132
	133	/*
	134	* Watchdog device is opened, and watchdog starts running.
	135	*/
	136	static int ks8695_wdt_open(struct inode inode, struct file file)
	137	{
	138	if (test_and_set_bit(0, &ks8695wdt_busy))
	139	return -EBUSY;
	140
	141	ks8695_wdt_start();
c5bf68fe	142	return stream_open(inode, file);
ccb8f430 AV	143	}
	144
	145	/*
	146	* Close the watchdog device.
	147	* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
	148	* disabled.
	149	*/
	150	static int ks8695_wdt_close(struct inode inode, struct file file)
	151	{
f4fabce1	152	/* Disable the watchdog when file is closed */
ccb8f430	153	if (!nowayout)
f4fabce1	154	ks8695_wdt_stop();
ccb8f430 AV	155	clear_bit(0, &ks8695wdt_busy);
	156	return 0;
	157	}
	158
42747d71	159	static const struct watchdog_info ks8695_wdt_info = {
ccb8f430 AV	160	.identity = "ks8695 watchdog",
	161	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	162	};
	163
	164	/*
	165	* Handle commands from user-space.
	166	*/
f4fabce1 AC	167	static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
f4fabce1 AC	168	unsigned long arg)
ccb8f430 AV	169	{
	170	void __user argp = (void __user )arg;
	171	int __user *p = argp;
	172	int new_value;
	173
f4fabce1	174	switch (cmd) {
f4fabce1 AC	175	case WDIOC_GETSUPPORT:
	176	return copy_to_user(argp, &ks8695_wdt_info,
	177	sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
f4fabce1 AC	178	case WDIOC_GETSTATUS:
	179	case WDIOC_GETBOOTSTATUS:
	180	return put_user(0, p);
	181	case WDIOC_SETOPTIONS:
	182	if (get_user(new_value, p))
	183	return -EFAULT;
	184	if (new_value & WDIOS_DISABLECARD)
	185	ks8695_wdt_stop();
	186	if (new_value & WDIOS_ENABLECARD)
ccb8f430	187	ks8695_wdt_start();
f4fabce1	188	return 0;
0c06090c WVS	189	case WDIOC_KEEPALIVE:
	190	ks8695_wdt_reload(); /* pat the watchdog */
	191	return 0;
	192	case WDIOC_SETTIMEOUT:
	193	if (get_user(new_value, p))
	194	return -EFAULT;
	195	if (ks8695_wdt_settimeout(new_value))
	196	return -EINVAL;
	197	/* Enable new time value */
	198	ks8695_wdt_start();
	199	/* Return current value */
	200	return put_user(wdt_time, p);
	201	case WDIOC_GETTIMEOUT:
	202	return put_user(wdt_time, p);
f4fabce1 AC	203	default:
f4fabce1 AC	204	return -ENOTTY;
ccb8f430 AV	205	}
	206	}
	207
	208	/*
	209	* Pat the watchdog whenever device is written to.
	210	*/
f4fabce1 AC	211	static ssize_t ks8695_wdt_write(struct file file, const char data,
f4fabce1 AC	212	size_t len, loff_t *ppos)
ccb8f430 AV	213	{
	214	ks8695_wdt_reload(); /* pat the watchdog */
	215	return len;
	216	}
	217
	218	/* ......................................................................... */
	219
	220	static const struct file_operations ks8695wdt_fops = {
	221	.owner = THIS_MODULE,
	222	.llseek = no_llseek,
f4fabce1	223	.unlocked_ioctl = ks8695_wdt_ioctl,
ccb8f430 AV	224	.open = ks8695_wdt_open,
	225	.release = ks8695_wdt_close,
	226	.write = ks8695_wdt_write,
	227	};
	228
	229	static struct miscdevice ks8695wdt_miscdev = {
	230	.minor = WATCHDOG_MINOR,
	231	.name = "watchdog",
	232	.fops = &ks8695wdt_fops,
	233	};
	234
2d991a16	235	static int ks8695wdt_probe(struct platform_device *pdev)
ccb8f430 AV	236	{
	237	int res;
	238
	239	if (ks8695wdt_miscdev.parent)
	240	return -EBUSY;
	241	ks8695wdt_miscdev.parent = &pdev->dev;
	242
	243	res = misc_register(&ks8695wdt_miscdev);
	244	if (res)
	245	return res;
	246
27c766aa JP	247	pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n",
27c766aa JP	248	wdt_time, nowayout ? ", nowayout" : "");
ccb8f430 AV	249	return 0;
	250	}
	251
4b12b896	252	static int ks8695wdt_remove(struct platform_device *pdev)
ccb8f430	253	{
f368ed60 GKH	254	misc_deregister(&ks8695wdt_miscdev);
f368ed60 GKH	255	ks8695wdt_miscdev.parent = NULL;
ccb8f430	256
f368ed60	257	return 0;
ccb8f430 AV	258	}
	259
	260	static void ks8695wdt_shutdown(struct platform_device *pdev)
	261	{
	262	ks8695_wdt_stop();
	263	}
	264
	265	#ifdef CONFIG_PM
	266
	267	static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
	268	{
	269	ks8695_wdt_stop();
	270	return 0;
	271	}
	272
	273	static int ks8695wdt_resume(struct platform_device *pdev)
	274	{
	275	if (ks8695wdt_busy)
	276	ks8695_wdt_start();
	277	return 0;
	278	}
	279
	280	#else
	281	#define ks8695wdt_suspend NULL
	282	#define ks8695wdt_resume NULL
	283	#endif
	284
	285	static struct platform_driver ks8695wdt_driver = {
	286	.probe = ks8695wdt_probe,
82268714	287	.remove = ks8695wdt_remove,
ccb8f430 AV	288	.shutdown = ks8695wdt_shutdown,
	289	.suspend = ks8695wdt_suspend,
	290	.resume = ks8695wdt_resume,
	291	.driver = {
	292	.name = "ks8695_wdt",
ccb8f430 AV	293	},
	294	};
	295
	296	static int __init ks8695_wdt_init(void)
	297	{
f4fabce1 AC	298	/* Check that the heartbeat value is within range;
f4fabce1 AC	299	if not reset to the default */
ccb8f430 AV	300	if (ks8695_wdt_settimeout(wdt_time)) {
ccb8f430 AV	301	ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
a77dba7e WVS	302	pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i"
a77dba7e WVS	303	", using %d\n", wdt_time, WDT_MAX_TIME);
ccb8f430	304	}
ccb8f430 AV	305	return platform_driver_register(&ks8695wdt_driver);
	306	}
	307
	308	static void __exit ks8695_wdt_exit(void)
	309	{
	310	platform_driver_unregister(&ks8695wdt_driver);
	311	}
	312
	313	module_init(ks8695_wdt_init);
	314	module_exit(ks8695_wdt_exit);
	315
	316	MODULE_AUTHOR("Andrew Victor");
	317	MODULE_DESCRIPTION("Watchdog driver for KS8695");
	318	MODULE_LICENSE("GPL");
f37d193c	319	MODULE_ALIAS("platform:ks8695_wdt");