[linux.git] / drivers / watchdog / bfin_wdt.c

/*
 * Blackfin On-Chip Watchdog Driver
 *
 * Originally based on softdog.c
 * Copyright 2006-2010 Analog Devices Inc.
 * Copyright 2006-2007 Michele d'Amico
 * Copyright 1996 Alan Cox <[email protected]>
 *
 * Enter bugs at http://blackfin.uclinux.org/
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/uaccess.h>
#include <asm/blackfin.h>
#include <asm/bfin_watchdog.h>

#define stamp(fmt, args...) \
	pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
#define stampit() stamp("here i am")
#define pr_devinit(fmt, args...) \
	({ static const __devinitconst char __fmt[] = fmt; \
	printk(__fmt, ## args); })
#define pr_init(fmt, args...) \
	({ static const __initconst char __fmt[] = fmt; \
	printk(__fmt, ## args); })

#define WATCHDOG_NAME "bfin-wdt"
#define PFX WATCHDOG_NAME ": "

/* The BF561 has two watchdogs (one per core), but since Linux
 * only runs on core A, we'll just work with that one.
 */
#ifdef BF561_FAMILY
# define bfin_read_WDOG_CTL()    bfin_read_WDOGA_CTL()
# define bfin_read_WDOG_CNT()    bfin_read_WDOGA_CNT()
# define bfin_read_WDOG_STAT()   bfin_read_WDOGA_STAT()
# define bfin_write_WDOG_CTL(x)  bfin_write_WDOGA_CTL(x)
# define bfin_write_WDOG_CNT(x)  bfin_write_WDOGA_CNT(x)
# define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
#endif

/* some defaults */
#define WATCHDOG_TIMEOUT 20

static unsigned int timeout = WATCHDOG_TIMEOUT;
static int nowayout = WATCHDOG_NOWAYOUT;
static const struct watchdog_info bfin_wdt_info;
static unsigned long open_check;
static char expect_close;
static DEFINE_SPINLOCK(bfin_wdt_spinlock);

/**
 *	bfin_wdt_keepalive - Keep the Userspace Watchdog Alive
 *
 *	The Userspace watchdog got a KeepAlive: schedule the next timeout.
 */
static int bfin_wdt_keepalive(void)
{
	stampit();
	bfin_write_WDOG_STAT(0);
	return 0;
}

/**
 *	bfin_wdt_stop - Stop the Watchdog
 *
 *	Stops the on-chip watchdog.
 */
static int bfin_wdt_stop(void)
{
	stampit();
	bfin_write_WDOG_CTL(WDEN_DISABLE);
	return 0;
}

/**
 *	bfin_wdt_start - Start the Watchdog
 *
 *	Starts the on-chip watchdog.  Automatically loads WDOG_CNT
 *	into WDOG_STAT for us.
 */
static int bfin_wdt_start(void)
{
	stampit();
	bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET);
	return 0;
}

/**
 *	bfin_wdt_running - Check Watchdog status
 *
 *	See if the watchdog is running.
 */
static int bfin_wdt_running(void)
{
	stampit();
	return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
}

/**
 *	bfin_wdt_set_timeout - Set the Userspace Watchdog timeout
 *	@t: new timeout value (in seconds)
 *
 *	Translate the specified timeout in seconds into System Clock
 *	terms which is what the on-chip Watchdog requires.
 */
static int bfin_wdt_set_timeout(unsigned long t)
{
	u32 cnt, max_t, sclk;
	unsigned long flags;

	sclk = get_sclk();
	max_t = -1 / sclk;
	cnt = t * sclk;
	stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt);

	if (t > max_t) {
		printk(KERN_WARNING PFX "timeout value is too large\n");
		return -EINVAL;
	}

	spin_lock_irqsave(&bfin_wdt_spinlock, flags);
	{
		int run = bfin_wdt_running();
		bfin_wdt_stop();
		bfin_write_WDOG_CNT(cnt);
		if (run)
			bfin_wdt_start();
	}
	spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);

	timeout = t;

	return 0;
}

/**
 *	bfin_wdt_open - Open the Device
 *	@inode: inode of device
 *	@file: file handle of device
 *
 *	Watchdog device is opened and started.
 */
static int bfin_wdt_open(struct inode *inode, struct file *file)
{
	stampit();

	if (test_and_set_bit(0, &open_check))
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	bfin_wdt_keepalive();
	bfin_wdt_start();

	return nonseekable_open(inode, file);
}

/**
 *	bfin_wdt_close - Close the Device
 *	@inode: inode of device
 *	@file: file handle of device
 *
 *	Watchdog device is closed and stopped.
 */
static int bfin_wdt_release(struct inode *inode, struct file *file)
{
	stampit();

	if (expect_close == 42)
		bfin_wdt_stop();
	else {
		printk(KERN_CRIT PFX
			"Unexpected close, not stopping watchdog!\n");
		bfin_wdt_keepalive();
	}
	expect_close = 0;
	clear_bit(0, &open_check);
	return 0;
}

/**
 *	bfin_wdt_write - Write to Device
 *	@file: file handle of device
 *	@buf: buffer to write
 *	@count: length of buffer
 *	@ppos: offset
 *
 *	Pings the watchdog on write.
 */
static ssize_t bfin_wdt_write(struct file *file, const char __user *data,
						size_t len, loff_t *ppos)
{
	stampit();

	if (len) {
		if (!nowayout) {
			size_t i;

			/* In case it was set long ago */
			expect_close = 0;

			for (i = 0; i != len; i++) {
				char c;
				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					expect_close = 42;
			}
		}
		bfin_wdt_keepalive();
	}

	return len;
}

/**
 *	bfin_wdt_ioctl - Query Device
 *	@file: file handle of device
 *	@cmd: watchdog command
 *	@arg: argument
 *
 *	Query basic information from the device or ping it, as outlined by the
 *	watchdog API.
 */
static long bfin_wdt_ioctl(struct file *file,
				unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;

	stampit();

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info)))
			return -EFAULT;
		else
			return 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p);
	case WDIOC_SETOPTIONS: {
		unsigned long flags;
		int options, ret = -EINVAL;

		if (get_user(options, p))
			return -EFAULT;

		spin_lock_irqsave(&bfin_wdt_spinlock, flags);
		if (options & WDIOS_DISABLECARD) {
			bfin_wdt_stop();
			ret = 0;
		}
		if (options & WDIOS_ENABLECARD) {
			bfin_wdt_start();
			ret = 0;
		}
		spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
		return ret;
	}
	case WDIOC_KEEPALIVE:
		bfin_wdt_keepalive();
		return 0;
	case WDIOC_SETTIMEOUT: {
		int new_timeout;

		if (get_user(new_timeout, p))
			return -EFAULT;
		if (bfin_wdt_set_timeout(new_timeout))
			return -EINVAL;
	}
	/* Fall */
	case WDIOC_GETTIMEOUT:
		return put_user(timeout, p);
	default:
		return -ENOTTY;
	}
}

#ifdef CONFIG_PM
static int state_before_suspend;

/**
 *	bfin_wdt_suspend - suspend the watchdog
 *	@pdev: device being suspended
 *	@state: requested suspend state
 *
 *	Remember if the watchdog was running and stop it.
 *	TODO: is this even right?  Doesn't seem to be any
 *	      standard in the watchdog world ...
 */
static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state)
{
	stampit();

	state_before_suspend = bfin_wdt_running();
	bfin_wdt_stop();

	return 0;
}

/**
 *	bfin_wdt_resume - resume the watchdog
 *	@pdev: device being resumed
 *
 *	If the watchdog was running, turn it back on.
 */
static int bfin_wdt_resume(struct platform_device *pdev)
{
	stampit();

	if (state_before_suspend) {
		bfin_wdt_set_timeout(timeout);
		bfin_wdt_start();
	}

	return 0;
}
#else
# define bfin_wdt_suspend NULL
# define bfin_wdt_resume NULL
#endif

static const struct file_operations bfin_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= bfin_wdt_write,
	.unlocked_ioctl	= bfin_wdt_ioctl,
	.open		= bfin_wdt_open,
	.release	= bfin_wdt_release,
};

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

static const struct watchdog_info bfin_wdt_info = {
	.identity = "Blackfin Watchdog",
	.options  = WDIOF_SETTIMEOUT |
		    WDIOF_KEEPALIVEPING |
		    WDIOF_MAGICCLOSE,
};

/**
 *	bfin_wdt_probe - Initialize module
 *
 *	Registers the misc device.  Actual device
 *	initialization is handled by bfin_wdt_open().
 */
static int __devinit bfin_wdt_probe(struct platform_device *pdev)
{
	int ret;

	ret = misc_register(&bfin_wdt_miscdev);
	if (ret) {
		pr_devinit(KERN_ERR PFX
			"cannot register miscdev on minor=%d (err=%d)\n",
				WATCHDOG_MINOR, ret);
		return ret;
	}

	pr_devinit(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
	       timeout, nowayout);

	return 0;
}

/**
 *	bfin_wdt_remove - Initialize module
 *
 *	Unregisters the misc device.  Actual device
 *	deinitialization is handled by bfin_wdt_close().
 */
static int __devexit bfin_wdt_remove(struct platform_device *pdev)
{
	misc_deregister(&bfin_wdt_miscdev);
	return 0;
}

/**
 *	bfin_wdt_shutdown - Soft Shutdown Handler
 *
 *	Handles the soft shutdown event.
 */
static void bfin_wdt_shutdown(struct platform_device *pdev)
{
	stampit();

	bfin_wdt_stop();
}

static struct platform_device *bfin_wdt_device;

static struct platform_driver bfin_wdt_driver = {
	.probe     = bfin_wdt_probe,
	.remove    = __devexit_p(bfin_wdt_remove),
	.shutdown  = bfin_wdt_shutdown,
	.suspend   = bfin_wdt_suspend,
	.resume    = bfin_wdt_resume,
	.driver    = {
		.name  = WATCHDOG_NAME,
		.owner = THIS_MODULE,
	},
};

/**
 *	bfin_wdt_init - Initialize module
 *
 *	Checks the module params and registers the platform device & driver.
 *	Real work is in the platform probe function.
 */
static int __init bfin_wdt_init(void)
{
	int ret;

	stampit();

	/* Check that the timeout value is within range */
	if (bfin_wdt_set_timeout(timeout))
		return -EINVAL;

	/* Since this is an on-chip device and needs no board-specific
	 * resources, we'll handle all the platform device stuff here.
	 */
	ret = platform_driver_register(&bfin_wdt_driver);
	if (ret) {
		pr_init(KERN_ERR PFX "unable to register driver\n");
		return ret;
	}

	bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME,
								-1, NULL, 0);
	if (IS_ERR(bfin_wdt_device)) {
		pr_init(KERN_ERR PFX "unable to register device\n");
		platform_driver_unregister(&bfin_wdt_driver);
		return PTR_ERR(bfin_wdt_device);
	}

	return 0;
}

/**
 *	bfin_wdt_exit - Deinitialize module
 *
 *	Back out the platform device & driver steps.  Real work is in the
 *	platform remove function.
 */
static void __exit bfin_wdt_exit(void)
{
	platform_device_unregister(bfin_wdt_device);
	platform_driver_unregister(&bfin_wdt_driver);
}

module_init(bfin_wdt_init);
module_exit(bfin_wdt_exit);

MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <[email protected]>");
MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
	"Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
		__MODULE_STRING(WATCHDOG_TIMEOUT) ")");

module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout,
	"Watchdog cannot be stopped once started (default="
		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Commit	Line	Data
1e6d320f BW	1	/*
1e6d320f BW	2	* Blackfin On-Chip Watchdog Driver
1e6d320f BW	3	*
1e6d320f BW	4	* Originally based on softdog.c
3dae93ec	5	* Copyright 2006-2010 Analog Devices Inc.
1e6d320f	6	* Copyright 2006-2007 Michele d'Amico
29fa0586	7	* Copyright 1996 Alan Cox <[email protected]>
1e6d320f BW	8	*
	9	* Enter bugs at http://blackfin.uclinux.org/
	10	*
	11	* Licensed under the GPL-2 or later.
	12	*/
	13
	14	#include <linux/platform_device.h>
	15	#include <linux/module.h>
	16	#include <linux/moduleparam.h>
	17	#include <linux/types.h>
	18	#include <linux/timer.h>
	19	#include <linux/miscdevice.h>
	20	#include <linux/watchdog.h>
	21	#include <linux/fs.h>
1e6d320f BW	22	#include <linux/init.h>
1e6d320f BW	23	#include <linux/interrupt.h>
9a5f50d3	24	#include <linux/uaccess.h>
089ab079	25	#include <asm/blackfin.h>
42bd5d49	26	#include <asm/bfin_watchdog.h>
1e6d320f	27
a77dba7e WVS	28	#define stamp(fmt, args...) \
a77dba7e WVS	29	pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
1e6d320f	30	#define stampit() stamp("here i am")
a77dba7e WVS	31	#define pr_devinit(fmt, args...) \
	32	({ static const __devinitconst char __fmt[] = fmt; \
	33	printk(__fmt, ## args); })
	34	#define pr_init(fmt, args...) \
	35	({ static const __initconst char __fmt[] = fmt; \
	36	printk(__fmt, ## args); })
1e6d320f BW	37
	38	#define WATCHDOG_NAME "bfin-wdt"
	39	#define PFX WATCHDOG_NAME ": "
	40
	41	/* The BF561 has two watchdogs (one per core), but since Linux
	42	* only runs on core A, we'll just work with that one.
	43	*/
	44	#ifdef BF561_FAMILY
	45	# define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL()
	46	# define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT()
	47	# define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT()
	48	# define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x)
	49	# define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x)
	50	# define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
	51	#endif
	52
1e6d320f BW	53	/* some defaults */
	54	#define WATCHDOG_TIMEOUT 20
	55
	56	static unsigned int timeout = WATCHDOG_TIMEOUT;
	57	static int nowayout = WATCHDOG_NOWAYOUT;
42747d71	58	static const struct watchdog_info bfin_wdt_info;
1e6d320f BW	59	static unsigned long open_check;
1e6d320f BW	60	static char expect_close;
bf6350a3	61	static DEFINE_SPINLOCK(bfin_wdt_spinlock);
1e6d320f BW	62
	63	/**
	64	* bfin_wdt_keepalive - Keep the Userspace Watchdog Alive
	65	*
5f3b2756	66	* The Userspace watchdog got a KeepAlive: schedule the next timeout.
1e6d320f BW	67	*/
	68	static int bfin_wdt_keepalive(void)
	69	{
	70	stampit();
	71	bfin_write_WDOG_STAT(0);
	72	return 0;
	73	}
	74
	75	/**
	76	* bfin_wdt_stop - Stop the Watchdog
	77	*
	78	* Stops the on-chip watchdog.
	79	*/
	80	static int bfin_wdt_stop(void)
	81	{
	82	stampit();
	83	bfin_write_WDOG_CTL(WDEN_DISABLE);
	84	return 0;
	85	}
	86
	87	/**
	88	* bfin_wdt_start - Start the Watchdog
	89	*
	90	* Starts the on-chip watchdog. Automatically loads WDOG_CNT
	91	* into WDOG_STAT for us.
	92	*/
	93	static int bfin_wdt_start(void)
	94	{
	95	stampit();
	96	bfin_write_WDOG_CTL(WDEN_ENABLE \| ICTL_RESET);
	97	return 0;
	98	}
	99
	100	/**
	101	* bfin_wdt_running - Check Watchdog status
	102	*
	103	* See if the watchdog is running.
	104	*/
	105	static int bfin_wdt_running(void)
	106	{
	107	stampit();
	108	return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
	109	}
	110
	111	/**
	112	* bfin_wdt_set_timeout - Set the Userspace Watchdog timeout
	113	* @t: new timeout value (in seconds)
	114	*
	115	* Translate the specified timeout in seconds into System Clock
	116	* terms which is what the on-chip Watchdog requires.
	117	*/
	118	static int bfin_wdt_set_timeout(unsigned long t)
	119	{
3dae93ec	120	u32 cnt, max_t, sclk;
1e6d320f BW	121	unsigned long flags;
1e6d320f BW	122
3dae93ec MF	123	sclk = get_sclk();
	124	max_t = -1 / sclk;
	125	cnt = t * sclk;
	126	stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt);
1e6d320f	127
3dae93ec	128	if (t > max_t) {
1e6d320f BW	129	printk(KERN_WARNING PFX "timeout value is too large\n");
	130	return -EINVAL;
	131	}
	132
	133	spin_lock_irqsave(&bfin_wdt_spinlock, flags);
	134	{
	135	int run = bfin_wdt_running();
	136	bfin_wdt_stop();
	137	bfin_write_WDOG_CNT(cnt);
9a5f50d3 AC	138	if (run)
9a5f50d3 AC	139	bfin_wdt_start();
1e6d320f BW	140	}
	141	spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
	142
	143	timeout = t;
	144
	145	return 0;
	146	}
	147
	148	/**
	149	* bfin_wdt_open - Open the Device
	150	* @inode: inode of device
	151	* @file: file handle of device
	152	*
	153	* Watchdog device is opened and started.
	154	*/
	155	static int bfin_wdt_open(struct inode inode, struct file file)
	156	{
	157	stampit();
	158
	159	if (test_and_set_bit(0, &open_check))
	160	return -EBUSY;
	161
	162	if (nowayout)
	163	__module_get(THIS_MODULE);
	164
	165	bfin_wdt_keepalive();
	166	bfin_wdt_start();
	167
	168	return nonseekable_open(inode, file);
	169	}
	170
	171	/**
	172	* bfin_wdt_close - Close the Device
	173	* @inode: inode of device
	174	* @file: file handle of device
	175	*
	176	* Watchdog device is closed and stopped.
	177	*/
	178	static int bfin_wdt_release(struct inode inode, struct file file)
	179	{
	180	stampit();
	181
9a5f50d3	182	if (expect_close == 42)
1e6d320f	183	bfin_wdt_stop();
9a5f50d3 AC	184	else {
	185	printk(KERN_CRIT PFX
	186	"Unexpected close, not stopping watchdog!\n");
1e6d320f BW	187	bfin_wdt_keepalive();
1e6d320f BW	188	}
1e6d320f BW	189	expect_close = 0;
1e6d320f BW	190	clear_bit(0, &open_check);
1e6d320f BW	191	return 0;
	192	}
	193
	194	/**
	195	* bfin_wdt_write - Write to Device
	196	* @file: file handle of device
	197	* @buf: buffer to write
	198	* @count: length of buffer
	199	* @ppos: offset
	200	*
	201	* Pings the watchdog on write.
	202	*/
	203	static ssize_t bfin_wdt_write(struct file file, const char __user data,
9a5f50d3	204	size_t len, loff_t *ppos)
1e6d320f BW	205	{
	206	stampit();
	207
	208	if (len) {
	209	if (!nowayout) {
	210	size_t i;
	211
	212	/* In case it was set long ago */
	213	expect_close = 0;
	214
	215	for (i = 0; i != len; i++) {
	216	char c;
	217	if (get_user(c, data + i))
	218	return -EFAULT;
	219	if (c == 'V')
	220	expect_close = 42;
	221	}
	222	}
	223	bfin_wdt_keepalive();
	224	}
	225
	226	return len;
	227	}
	228
	229	/**
	230	* bfin_wdt_ioctl - Query Device
1e6d320f BW	231	* @file: file handle of device
	232	* @cmd: watchdog command
	233	* @arg: argument
	234	*
	235	* Query basic information from the device or ping it, as outlined by the
	236	* watchdog API.
	237	*/
9a5f50d3 AC	238	static long bfin_wdt_ioctl(struct file *file,
9a5f50d3 AC	239	unsigned int cmd, unsigned long arg)
1e6d320f BW	240	{
	241	void __user argp = (void __user )arg;
	242	int __user *p = argp;
	243
	244	stampit();
	245
	246	switch (cmd) {
9a5f50d3 AC	247	case WDIOC_GETSUPPORT:
	248	if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info)))
	249	return -EFAULT;
	250	else
1e6d320f	251	return 0;
9a5f50d3 AC	252	case WDIOC_GETSTATUS:
	253	case WDIOC_GETBOOTSTATUS:
	254	return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p);
9a5f50d3 AC	255	case WDIOC_SETOPTIONS: {
	256	unsigned long flags;
	257	int options, ret = -EINVAL;
	258
	259	if (get_user(options, p))
	260	return -EFAULT;
	261
	262	spin_lock_irqsave(&bfin_wdt_spinlock, flags);
	263	if (options & WDIOS_DISABLECARD) {
	264	bfin_wdt_stop();
	265	ret = 0;
1e6d320f	266	}
9a5f50d3 AC	267	if (options & WDIOS_ENABLECARD) {
	268	bfin_wdt_start();
	269	ret = 0;
1e6d320f	270	}
9a5f50d3 AC	271	spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
	272	return ret;
	273	}
0c06090c WVS	274	case WDIOC_KEEPALIVE:
	275	bfin_wdt_keepalive();
	276	return 0;
	277	case WDIOC_SETTIMEOUT: {
	278	int new_timeout;
	279
	280	if (get_user(new_timeout, p))
	281	return -EFAULT;
	282	if (bfin_wdt_set_timeout(new_timeout))
	283	return -EINVAL;
	284	}
	285	/* Fall */
	286	case WDIOC_GETTIMEOUT:
	287	return put_user(timeout, p);
9a5f50d3 AC	288	default:
9a5f50d3 AC	289	return -ENOTTY;
1e6d320f BW	290	}
	291	}
	292
1e6d320f BW	293	#ifdef CONFIG_PM
	294	static int state_before_suspend;
	295
	296	/**
	297	* bfin_wdt_suspend - suspend the watchdog
	298	* @pdev: device being suspended
	299	* @state: requested suspend state
	300	*
	301	* Remember if the watchdog was running and stop it.
	302	* TODO: is this even right? Doesn't seem to be any
	303	* standard in the watchdog world ...
	304	*/
	305	static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state)
	306	{
	307	stampit();
	308
	309	state_before_suspend = bfin_wdt_running();
	310	bfin_wdt_stop();
	311
	312	return 0;
	313	}
	314
	315	/**
	316	* bfin_wdt_resume - resume the watchdog
	317	* @pdev: device being resumed
	318	*
	319	* If the watchdog was running, turn it back on.
	320	*/
	321	static int bfin_wdt_resume(struct platform_device *pdev)
	322	{
	323	stampit();
	324
	325	if (state_before_suspend) {
	326	bfin_wdt_set_timeout(timeout);
	327	bfin_wdt_start();
	328	}
	329
	330	return 0;
	331	}
	332	#else
	333	# define bfin_wdt_suspend NULL
	334	# define bfin_wdt_resume NULL
	335	#endif
	336
b47a166e	337	static const struct file_operations bfin_wdt_fops = {
9a5f50d3 AC	338	.owner = THIS_MODULE,
9a5f50d3 AC	339	.llseek = no_llseek,
5f3b2756	340	.write = bfin_wdt_write,
9a5f50d3 AC	341	.unlocked_ioctl = bfin_wdt_ioctl,
	342	.open = bfin_wdt_open,
	343	.release = bfin_wdt_release,
1e6d320f BW	344	};
	345
	346	static struct miscdevice bfin_wdt_miscdev = {
	347	.minor = WATCHDOG_MINOR,
	348	.name = "watchdog",
	349	.fops = &bfin_wdt_fops,
	350	};
	351
42747d71	352	static const struct watchdog_info bfin_wdt_info = {
1e6d320f BW	353	.identity = "Blackfin Watchdog",
1e6d320f BW	354	.options = WDIOF_SETTIMEOUT \|
9a5f50d3 AC	355	WDIOF_KEEPALIVEPING \|
9a5f50d3 AC	356	WDIOF_MAGICCLOSE,
1e6d320f BW	357	};
1e6d320f BW	358
1e6d320f	359	/**
93539b19	360	* bfin_wdt_probe - Initialize module
1e6d320f	361	*
168b5251	362	* Registers the misc device. Actual device
1e6d320f BW	363	* initialization is handled by bfin_wdt_open().
1e6d320f BW	364	*/
93539b19 MF	365	static int __devinit bfin_wdt_probe(struct platform_device *pdev)
	366	{
	367	int ret;
	368
93539b19 MF	369	ret = misc_register(&bfin_wdt_miscdev);
93539b19 MF	370	if (ret) {
9a5f50d3 AC	371	pr_devinit(KERN_ERR PFX
	372	"cannot register miscdev on minor=%d (err=%d)\n",
	373	WATCHDOG_MINOR, ret);
93539b19 MF	374	return ret;
	375	}
	376
	377	pr_devinit(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
	378	timeout, nowayout);
	379
	380	return 0;
	381	}
	382
	383	/**
	384	* bfin_wdt_remove - Initialize module
	385	*
168b5251	386	* Unregisters the misc device. Actual device
93539b19 MF	387	* deinitialization is handled by bfin_wdt_close().
	388	*/
	389	static int __devexit bfin_wdt_remove(struct platform_device *pdev)
	390	{
	391	misc_deregister(&bfin_wdt_miscdev);
93539b19 MF	392	return 0;
	393	}
	394
168b5251 WVS	395	/**
	396	* bfin_wdt_shutdown - Soft Shutdown Handler
	397	*
	398	* Handles the soft shutdown event.
	399	*/
	400	static void bfin_wdt_shutdown(struct platform_device *pdev)
	401	{
	402	stampit();
	403
	404	bfin_wdt_stop();
	405	}
	406
93539b19 MF	407	static struct platform_device *bfin_wdt_device;
	408
	409	static struct platform_driver bfin_wdt_driver = {
	410	.probe = bfin_wdt_probe,
	411	.remove = __devexit_p(bfin_wdt_remove),
168b5251	412	.shutdown = bfin_wdt_shutdown,
93539b19 MF	413	.suspend = bfin_wdt_suspend,
	414	.resume = bfin_wdt_resume,
	415	.driver = {
	416	.name = WATCHDOG_NAME,
	417	.owner = THIS_MODULE,
	418	},
	419	};
	420
	421	/**
	422	* bfin_wdt_init - Initialize module
	423	*
	424	* Checks the module params and registers the platform device & driver.
	425	* Real work is in the platform probe function.
	426	*/
1e6d320f BW	427	static int __init bfin_wdt_init(void)
	428	{
	429	int ret;
	430
	431	stampit();
	432
	433	/* Check that the timeout value is within range */
	434	if (bfin_wdt_set_timeout(timeout))
	435	return -EINVAL;
	436
	437	/* Since this is an on-chip device and needs no board-specific
	438	* resources, we'll handle all the platform device stuff here.
	439	*/
93539b19	440	ret = platform_driver_register(&bfin_wdt_driver);
1e6d320f	441	if (ret) {
93539b19	442	pr_init(KERN_ERR PFX "unable to register driver\n");
1e6d320f BW	443	return ret;
	444	}
	445
a77dba7e WVS	446	bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME,
a77dba7e WVS	447	-1, NULL, 0);
93539b19 MF	448	if (IS_ERR(bfin_wdt_device)) {
	449	pr_init(KERN_ERR PFX "unable to register device\n");
	450	platform_driver_unregister(&bfin_wdt_driver);
	451	return PTR_ERR(bfin_wdt_device);
1e6d320f BW	452	}
1e6d320f BW	453
1e6d320f BW	454	return 0;
	455	}
	456
	457	/**
	458	* bfin_wdt_exit - Deinitialize module
	459	*
93539b19 MF	460	* Back out the platform device & driver steps. Real work is in the
93539b19 MF	461	* platform remove function.
1e6d320f BW	462	*/
	463	static void __exit bfin_wdt_exit(void)
	464	{
93539b19 MF	465	platform_device_unregister(bfin_wdt_device);
93539b19 MF	466	platform_driver_unregister(&bfin_wdt_driver);
1e6d320f BW	467	}
	468
	469	module_init(bfin_wdt_init);
	470	module_exit(bfin_wdt_exit);
	471
	472	MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <[email protected]>");
	473	MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
	474	MODULE_LICENSE("GPL");
	475	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	476
	477	module_param(timeout, uint, 0);
9a5f50d3 AC	478	MODULE_PARM_DESC(timeout,
	479	"Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
	480	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
1e6d320f BW	481
1e6d320f BW	482	module_param(nowayout, int, 0);
9a5f50d3 AC	483	MODULE_PARM_DESC(nowayout,
	484	"Watchdog cannot be stopped once started (default="
	485	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");