[thirdparty/kernel/linux.git] / drivers / watchdog / shwdt.c

/*
 * drivers/watchdog/shwdt.c
 *
 * Watchdog driver for integrated watchdog in the SuperH processors.
 *
 * Copyright (C) 2001 - 2010  Paul Mundt <lethal@linux-sh.org>
 *
 * 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.
 *
 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
 *     Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
 *
 * 19-Apr-2002 Rob Radez <rob@osinvestor.com>
 *     Added expect close support, made emulated timeout runtime changeable
 *     general cleanups, add some ioctls
 */
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/notifier.h>
#include <linux/ioport.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <asm/watchdog.h>

#define DRV_NAME "sh-wdt"

/*
 * Default clock division ratio is 5.25 msecs. For an additional table of
 * values, consult the asm-sh/watchdog.h. Overload this at module load
 * time.
 *
 * In order for this to work reliably we need to have HZ set to 1000 or
 * something quite higher than 100 (or we need a proper high-res timer
 * implementation that will deal with this properly), otherwise the 10ms
 * resolution of a jiffy is enough to trigger the overflow. For things like
 * the SH-4 and SH-5, this isn't necessarily that big of a problem, though
 * for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely
 * necssary.
 *
 * As a result of this timing problem, the only modes that are particularly
 * feasible are the 4096 and the 2048 divisors, which yield 5.25 and 2.62ms
 * overflow periods respectively.
 *
 * Also, since we can't really expect userspace to be responsive enough
 * before the overflow happens, we maintain two separate timers .. One in
 * the kernel for clearing out WOVF every 2ms or so (again, this depends on
 * HZ == 1000), and another for monitoring userspace writes to the WDT device.
 *
 * As such, we currently use a configurable heartbeat interval which defaults
 * to 30s. In this case, the userspace daemon is only responsible for periodic
 * writes to the device before the next heartbeat is scheduled. If the daemon
 * misses its deadline, the kernel timer will allow the WDT to overflow.
 */
static int clock_division_ratio = WTCSR_CKS_4096;
#define next_ping_period(cks)	msecs_to_jiffies(cks - 4)

static const struct watchdog_info sh_wdt_info;
static struct platform_device *sh_wdt_dev;
static DEFINE_SPINLOCK(shwdt_lock);

#define WATCHDOG_HEARTBEAT 30			/* 30 sec default heartbeat */
static int heartbeat = WATCHDOG_HEARTBEAT;	/* in seconds */
static int nowayout = WATCHDOG_NOWAYOUT;
static unsigned long next_heartbeat;

struct sh_wdt {
	void __iomem		*base;
	struct device		*dev;

	struct timer_list	timer;

	unsigned long		enabled;
	char			expect_close;
};

static void sh_wdt_start(struct sh_wdt *wdt)
{
	unsigned long flags;
	u8 csr;

	spin_lock_irqsave(&shwdt_lock, flags);

	next_heartbeat = jiffies + (heartbeat * HZ);
	mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));

	csr = sh_wdt_read_csr();
	csr |= WTCSR_WT | clock_division_ratio;
	sh_wdt_write_csr(csr);

	sh_wdt_write_cnt(0);

	/*
	 * These processors have a bit of an inconsistent initialization
	 * process.. starting with SH-3, RSTS was moved to WTCSR, and the
	 * RSTCSR register was removed.
	 *
	 * On the SH-2 however, in addition with bits being in different
	 * locations, we must deal with RSTCSR outright..
	 */
	csr = sh_wdt_read_csr();
	csr |= WTCSR_TME;
	csr &= ~WTCSR_RSTS;
	sh_wdt_write_csr(csr);

#ifdef CONFIG_CPU_SH2
	csr = sh_wdt_read_rstcsr();
	csr &= ~RSTCSR_RSTS;
	sh_wdt_write_rstcsr(csr);
#endif
	spin_unlock_irqrestore(&shwdt_lock, flags);
}

static void sh_wdt_stop(struct sh_wdt *wdt)
{
	unsigned long flags;
	u8 csr;

	spin_lock_irqsave(&shwdt_lock, flags);

	del_timer(&wdt->timer);

	csr = sh_wdt_read_csr();
	csr &= ~WTCSR_TME;
	sh_wdt_write_csr(csr);

	spin_unlock_irqrestore(&shwdt_lock, flags);
}

static inline void sh_wdt_keepalive(struct sh_wdt *wdt)
{
	unsigned long flags;

	spin_lock_irqsave(&shwdt_lock, flags);
	next_heartbeat = jiffies + (heartbeat * HZ);
	spin_unlock_irqrestore(&shwdt_lock, flags);
}

static int sh_wdt_set_heartbeat(int t)
{
	unsigned long flags;

	if (unlikely(t < 1 || t > 3600)) /* arbitrary upper limit */
		return -EINVAL;

	spin_lock_irqsave(&shwdt_lock, flags);
	heartbeat = t;
	spin_unlock_irqrestore(&shwdt_lock, flags);
	return 0;
}

static void sh_wdt_ping(unsigned long data)
{
	struct sh_wdt *wdt = (struct sh_wdt *)data;
	unsigned long flags;

	spin_lock_irqsave(&shwdt_lock, flags);
	if (time_before(jiffies, next_heartbeat)) {
		u8 csr;

		csr = sh_wdt_read_csr();
		csr &= ~WTCSR_IOVF;
		sh_wdt_write_csr(csr);

		sh_wdt_write_cnt(0);

		mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
	} else
		dev_warn(wdt->dev, "Heartbeat lost! Will not ping "
		         "the watchdog\n");
	spin_unlock_irqrestore(&shwdt_lock, flags);
}

static int sh_wdt_open(struct inode *inode, struct file *file)
{
	struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev);

	if (test_and_set_bit(0, &wdt->enabled))
		return -EBUSY;
	if (nowayout)
		__module_get(THIS_MODULE);

	file->private_data = wdt;

	sh_wdt_start(wdt);

	return nonseekable_open(inode, file);
}

static int sh_wdt_close(struct inode *inode, struct file *file)
{
	struct sh_wdt *wdt = file->private_data;

	if (wdt->expect_close == 42) {
		sh_wdt_stop(wdt);
	} else {
		dev_crit(wdt->dev, "Unexpected close, not "
		         "stopping watchdog!\n");
		sh_wdt_keepalive(wdt);
	}

	clear_bit(0, &wdt->enabled);
	wdt->expect_close = 0;

	return 0;
}

static ssize_t sh_wdt_write(struct file *file, const char *buf,
			    size_t count, loff_t *ppos)
{
	struct sh_wdt *wdt = file->private_data;

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

			wdt->expect_close = 0;

			for (i = 0; i != count; i++) {
				char c;
				if (get_user(c, buf + i))
					return -EFAULT;
				if (c == 'V')
					wdt->expect_close = 42;
			}
		}
		sh_wdt_keepalive(wdt);
	}

	return count;
}

static long sh_wdt_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	struct sh_wdt *wdt = file->private_data;
	int new_heartbeat;
	int options, retval = -EINVAL;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user((struct watchdog_info *)arg,
			  &sh_wdt_info, sizeof(sh_wdt_info)) ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, (int *)arg);
	case WDIOC_SETOPTIONS:
		if (get_user(options, (int *)arg))
			return -EFAULT;

		if (options & WDIOS_DISABLECARD) {
			sh_wdt_stop(wdt);
			retval = 0;
		}

		if (options & WDIOS_ENABLECARD) {
			sh_wdt_start(wdt);
			retval = 0;
		}

		return retval;
	case WDIOC_KEEPALIVE:
		sh_wdt_keepalive(wdt);
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_heartbeat, (int *)arg))
			return -EFAULT;

		if (sh_wdt_set_heartbeat(new_heartbeat))
			return -EINVAL;

		sh_wdt_keepalive(wdt);
		/* Fall */
	case WDIOC_GETTIMEOUT:
		return put_user(heartbeat, (int *)arg);
	default:
		return -ENOTTY;
	}
	return 0;
}

static int sh_wdt_notify_sys(struct notifier_block *this,
			     unsigned long code, void *unused)
{
	struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev);

	if (code == SYS_DOWN || code == SYS_HALT)
		sh_wdt_stop(wdt);

	return NOTIFY_DONE;
}

static const struct file_operations sh_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= sh_wdt_write,
	.unlocked_ioctl	= sh_wdt_ioctl,
	.open		= sh_wdt_open,
	.release	= sh_wdt_close,
};

static const struct watchdog_info sh_wdt_info = {
	.options		= WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
				  WDIOF_MAGICCLOSE,
	.firmware_version	= 1,
	.identity		= "SH WDT",
};

static struct notifier_block sh_wdt_notifier = {
	.notifier_call		= sh_wdt_notify_sys,
};

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

static int __devinit sh_wdt_probe(struct platform_device *pdev)
{
	struct sh_wdt *wdt;
	struct resource *res;
	int rc;

	/*
	 * As this driver only covers the global watchdog case, reject
	 * any attempts to register per-CPU watchdogs.
	 */
	if (pdev->id != -1)
		return -EINVAL;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (unlikely(!res))
		return -EINVAL;

	if (!devm_request_mem_region(&pdev->dev, res->start,
				     resource_size(res), DRV_NAME))
		return -EBUSY;

	wdt = devm_kzalloc(&pdev->dev, sizeof(struct sh_wdt), GFP_KERNEL);
	if (unlikely(!wdt)) {
		rc = -ENOMEM;
		goto out_release;
	}

	wdt->dev = &pdev->dev;

	wdt->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
	if (unlikely(!wdt->base)) {
		rc = -ENXIO;
		goto out_err;
	}

	rc = register_reboot_notifier(&sh_wdt_notifier);
	if (unlikely(rc)) {
		dev_err(&pdev->dev,
			"Can't register reboot notifier (err=%d)\n", rc);
		goto out_unmap;
	}

	sh_wdt_miscdev.parent = wdt->dev;

	rc = misc_register(&sh_wdt_miscdev);
	if (unlikely(rc)) {
		dev_err(&pdev->dev,
			"Can't register miscdev on minor=%d (err=%d)\n",
						sh_wdt_miscdev.minor, rc);
		goto out_unreg;
	}

	init_timer(&wdt->timer);
	wdt->timer.function	= sh_wdt_ping;
	wdt->timer.data		= (unsigned long)wdt;
	wdt->timer.expires	= next_ping_period(clock_division_ratio);

	platform_set_drvdata(pdev, wdt);
	sh_wdt_dev = pdev;

	dev_info(&pdev->dev, "initialized.\n");

	return 0;

out_unreg:
	unregister_reboot_notifier(&sh_wdt_notifier);
out_unmap:
	devm_iounmap(&pdev->dev, wdt->base);
out_err:
	devm_kfree(&pdev->dev, wdt);
out_release:
	devm_release_mem_region(&pdev->dev, res->start, resource_size(res));

	return rc;
}

static int __devexit sh_wdt_remove(struct platform_device *pdev)
{
	struct sh_wdt *wdt = platform_get_drvdata(pdev);
	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	platform_set_drvdata(pdev, NULL);

	misc_deregister(&sh_wdt_miscdev);

	sh_wdt_dev = NULL;

	unregister_reboot_notifier(&sh_wdt_notifier);
	devm_release_mem_region(&pdev->dev, res->start, resource_size(res));
	devm_iounmap(&pdev->dev, wdt->base);
	devm_kfree(&pdev->dev, wdt);

	return 0;
}

static struct platform_driver sh_wdt_driver = {
	.driver		= {
		.name	= DRV_NAME,
		.owner	= THIS_MODULE,
	},

	.probe	= sh_wdt_probe,
	.remove	= __devexit_p(sh_wdt_remove),
};

static int __init sh_wdt_init(void)
{
	int rc;

	if (unlikely(clock_division_ratio < 0x5 ||
		     clock_division_ratio > 0x7)) {
		clock_division_ratio = WTCSR_CKS_4096;

		pr_info("%s: divisor must be 0x5<=x<=0x7, using %d\n",
			 DRV_NAME, clock_division_ratio);
	}

	rc = sh_wdt_set_heartbeat(heartbeat);
	if (unlikely(rc)) {
		heartbeat = WATCHDOG_HEARTBEAT;

		pr_info("%s: heartbeat value must be 1<=x<=3600, using %d\n",
			DRV_NAME, heartbeat);
	}

	pr_info("%s: configured with heartbeat=%d sec (nowayout=%d)\n",
		DRV_NAME, heartbeat, nowayout);

	return platform_driver_register(&sh_wdt_driver);
}

static void __exit sh_wdt_exit(void)
{
	platform_driver_unregister(&sh_wdt_driver);
}
module_init(sh_wdt_init);
module_exit(sh_wdt_exit);

MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
MODULE_DESCRIPTION("SuperH watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

module_param(clock_division_ratio, int, 0);
MODULE_PARM_DESC(clock_division_ratio,
	"Clock division ratio. Valid ranges are from 0x5 (1.31ms) "
	"to 0x7 (5.25ms). (default=" __MODULE_STRING(WTCSR_CKS_4096) ")");

module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
	"Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default="
				__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");

module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout,
	"Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Commit	Line	Data
1da177e4	1	/*
b1fa888e	2	* drivers/watchdog/shwdt.c
1da177e4 LT	3	*
	4	* Watchdog driver for integrated watchdog in the SuperH processors.
	5	*
b1fa888e	6	* Copyright (C) 2001 - 2010 Paul Mundt <lethal@linux-sh.org>
1da177e4 LT	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms of the GNU General Public License as published by the
	10	* Free Software Foundation; either version 2 of the License, or (at your
	11	* option) any later version.
	12	*
	13	* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
	14	* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
	15	*
	16	* 19-Apr-2002 Rob Radez <rob@osinvestor.com>
	17	* Added expect close support, made emulated timeout runtime changeable
	18	* general cleanups, add some ioctls
	19	*/
1da177e4 LT	20	#include <linux/module.h>
1da177e4 LT	21	#include <linux/moduleparam.h>
8f5585ec	22	#include <linux/platform_device.h>
1da177e4 LT	23	#include <linux/init.h>
	24	#include <linux/types.h>
	25	#include <linux/miscdevice.h>
	26	#include <linux/watchdog.h>
	27	#include <linux/reboot.h>
	28	#include <linux/notifier.h>
	29	#include <linux/ioport.h>
	30	#include <linux/fs.h>
f118420b	31	#include <linux/mm.h>
8f5585ec	32	#include <linux/slab.h>
70b814ec AC	33	#include <linux/io.h>
70b814ec AC	34	#include <linux/uaccess.h>
58cf4198	35	#include <asm/watchdog.h>
1da177e4	36
8f5585ec	37	#define DRV_NAME "sh-wdt"
1da177e4 LT	38
	39	/*
	40	* Default clock division ratio is 5.25 msecs. For an additional table of
	41	* values, consult the asm-sh/watchdog.h. Overload this at module load
	42	* time.
	43	*
	44	* In order for this to work reliably we need to have HZ set to 1000 or
	45	* something quite higher than 100 (or we need a proper high-res timer
	46	* implementation that will deal with this properly), otherwise the 10ms
	47	* resolution of a jiffy is enough to trigger the overflow. For things like
	48	* the SH-4 and SH-5, this isn't necessarily that big of a problem, though
	49	* for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely
	50	* necssary.
	51	*
	52	* As a result of this timing problem, the only modes that are particularly
25985edc	53	* feasible are the 4096 and the 2048 divisors, which yield 5.25 and 2.62ms
1da177e4 LT	54	* overflow periods respectively.
	55	*
	56	* Also, since we can't really expect userspace to be responsive enough
ee0fc097	57	* before the overflow happens, we maintain two separate timers .. One in
1da177e4 LT	58	* the kernel for clearing out WOVF every 2ms or so (again, this depends on
	59	* HZ == 1000), and another for monitoring userspace writes to the WDT device.
	60	*
	61	* As such, we currently use a configurable heartbeat interval which defaults
	62	* to 30s. In this case, the userspace daemon is only responsible for periodic
	63	* writes to the device before the next heartbeat is scheduled. If the daemon
	64	* misses its deadline, the kernel timer will allow the WDT to overflow.
	65	*/
	66	static int clock_division_ratio = WTCSR_CKS_4096;
1da177e4 LT	67	#define next_ping_period(cks) msecs_to_jiffies(cks - 4)
1da177e4 LT	68
58cf4198	69	static const struct watchdog_info sh_wdt_info;
8f5585ec	70	static struct platform_device *sh_wdt_dev;
70b814ec	71	static DEFINE_SPINLOCK(shwdt_lock);
1da177e4 LT	72
	73	#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat */
	74	static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
4bfdf378	75	static int nowayout = WATCHDOG_NOWAYOUT;
8f5585ec PM	76	static unsigned long next_heartbeat;
	77
	78	struct sh_wdt {
	79	void __iomem *base;
	80	struct device *dev;
1da177e4	81
8f5585ec PM	82	struct timer_list timer;
	83
	84	unsigned long enabled;
	85	char expect_close;
	86	};
	87
	88	static void sh_wdt_start(struct sh_wdt *wdt)
1da177e4	89	{
70b814ec	90	unsigned long flags;
8f5585ec	91	u8 csr;
70b814ec	92
58cf4198	93	spin_lock_irqsave(&shwdt_lock, flags);
1da177e4 LT	94
1da177e4 LT	95	next_heartbeat = jiffies + (heartbeat * HZ);
8f5585ec	96	mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
1da177e4 LT	97
	98	csr = sh_wdt_read_csr();
	99	csr \|= WTCSR_WT \| clock_division_ratio;
	100	sh_wdt_write_csr(csr);
	101
	102	sh_wdt_write_cnt(0);
	103
	104	/*
	105	* These processors have a bit of an inconsistent initialization
	106	* process.. starting with SH-3, RSTS was moved to WTCSR, and the
	107	* RSTCSR register was removed.
	108	*
	109	* On the SH-2 however, in addition with bits being in different
	110	* locations, we must deal with RSTCSR outright..
	111	*/
	112	csr = sh_wdt_read_csr();
	113	csr \|= WTCSR_TME;
	114	csr &= ~WTCSR_RSTS;
	115	sh_wdt_write_csr(csr);
	116
	117	#ifdef CONFIG_CPU_SH2
1da177e4 LT	118	csr = sh_wdt_read_rstcsr();
	119	csr &= ~RSTCSR_RSTS;
	120	sh_wdt_write_rstcsr(csr);
	121	#endif
58cf4198	122	spin_unlock_irqrestore(&shwdt_lock, flags);
1da177e4 LT	123	}
1da177e4 LT	124
8f5585ec	125	static void sh_wdt_stop(struct sh_wdt *wdt)
1da177e4	126	{
70b814ec	127	unsigned long flags;
8f5585ec	128	u8 csr;
70b814ec	129
58cf4198	130	spin_lock_irqsave(&shwdt_lock, flags);
1da177e4	131
8f5585ec	132	del_timer(&wdt->timer);
1da177e4 LT	133
	134	csr = sh_wdt_read_csr();
	135	csr &= ~WTCSR_TME;
	136	sh_wdt_write_csr(csr);
8f5585ec	137
58cf4198	138	spin_unlock_irqrestore(&shwdt_lock, flags);
1da177e4 LT	139	}
1da177e4 LT	140
8f5585ec	141	static inline void sh_wdt_keepalive(struct sh_wdt *wdt)
1da177e4	142	{
70b814ec AC	143	unsigned long flags;
70b814ec AC	144
58cf4198	145	spin_lock_irqsave(&shwdt_lock, flags);
1da177e4	146	next_heartbeat = jiffies + (heartbeat * HZ);
58cf4198	147	spin_unlock_irqrestore(&shwdt_lock, flags);
1da177e4 LT	148	}
1da177e4 LT	149
1da177e4 LT	150	static int sh_wdt_set_heartbeat(int t)
1da177e4 LT	151	{
70b814ec AC	152	unsigned long flags;
	153
	154	if (unlikely(t < 1 \|\| t > 3600)) /* arbitrary upper limit */
1da177e4 LT	155	return -EINVAL;
1da177e4 LT	156
58cf4198	157	spin_lock_irqsave(&shwdt_lock, flags);
1da177e4	158	heartbeat = t;
58cf4198	159	spin_unlock_irqrestore(&shwdt_lock, flags);
1da177e4 LT	160	return 0;
	161	}
	162
1da177e4 LT	163	static void sh_wdt_ping(unsigned long data)
1da177e4 LT	164	{
8f5585ec	165	struct sh_wdt wdt = (struct sh_wdt )data;
70b814ec AC	166	unsigned long flags;
70b814ec AC	167
58cf4198	168	spin_lock_irqsave(&shwdt_lock, flags);
1da177e4	169	if (time_before(jiffies, next_heartbeat)) {
8f5585ec	170	u8 csr;
1da177e4 LT	171
	172	csr = sh_wdt_read_csr();
	173	csr &= ~WTCSR_IOVF;
	174	sh_wdt_write_csr(csr);
	175
	176	sh_wdt_write_cnt(0);
	177
8f5585ec	178	mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));
e4c2cfee	179	} else
8f5585ec PM	180	dev_warn(wdt->dev, "Heartbeat lost! Will not ping "
8f5585ec PM	181	"the watchdog\n");
58cf4198	182	spin_unlock_irqrestore(&shwdt_lock, flags);
1da177e4 LT	183	}
1da177e4 LT	184
1da177e4 LT	185	static int sh_wdt_open(struct inode inode, struct file file)
1da177e4 LT	186	{
8f5585ec PM	187	struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev);
	188
	189	if (test_and_set_bit(0, &wdt->enabled))
1da177e4 LT	190	return -EBUSY;
	191	if (nowayout)
	192	__module_get(THIS_MODULE);
	193
8f5585ec PM	194	file->private_data = wdt;
	195
	196	sh_wdt_start(wdt);
1da177e4 LT	197
	198	return nonseekable_open(inode, file);
	199	}
	200
1da177e4 LT	201	static int sh_wdt_close(struct inode inode, struct file file)
1da177e4 LT	202	{
8f5585ec PM	203	struct sh_wdt *wdt = file->private_data;
	204
	205	if (wdt->expect_close == 42) {
	206	sh_wdt_stop(wdt);
1da177e4	207	} else {
8f5585ec PM	208	dev_crit(wdt->dev, "Unexpected close, not "
	209	"stopping watchdog!\n");
	210	sh_wdt_keepalive(wdt);
1da177e4 LT	211	}
1da177e4 LT	212
8f5585ec PM	213	clear_bit(0, &wdt->enabled);
8f5585ec PM	214	wdt->expect_close = 0;
1da177e4 LT	215
	216	return 0;
	217	}
	218
1da177e4 LT	219	static ssize_t sh_wdt_write(struct file file, const char buf,
	220	size_t count, loff_t *ppos)
	221	{
8f5585ec PM	222	struct sh_wdt *wdt = file->private_data;
8f5585ec PM	223
1da177e4 LT	224	if (count) {
	225	if (!nowayout) {
	226	size_t i;
	227
8f5585ec	228	wdt->expect_close = 0;
1da177e4 LT	229
	230	for (i = 0; i != count; i++) {
	231	char c;
	232	if (get_user(c, buf + i))
	233	return -EFAULT;
	234	if (c == 'V')
8f5585ec	235	wdt->expect_close = 42;
1da177e4 LT	236	}
1da177e4 LT	237	}
8f5585ec	238	sh_wdt_keepalive(wdt);
1da177e4 LT	239	}
	240
	241	return count;
	242	}
	243
70b814ec AC	244	static long sh_wdt_ioctl(struct file *file, unsigned int cmd,
70b814ec AC	245	unsigned long arg)
1da177e4	246	{
8f5585ec	247	struct sh_wdt *wdt = file->private_data;
1da177e4 LT	248	int new_heartbeat;
	249	int options, retval = -EINVAL;
	250
	251	switch (cmd) {
70b814ec AC	252	case WDIOC_GETSUPPORT:
	253	return copy_to_user((struct watchdog_info *)arg,
	254	&sh_wdt_info, sizeof(sh_wdt_info)) ? -EFAULT : 0;
	255	case WDIOC_GETSTATUS:
	256	case WDIOC_GETBOOTSTATUS:
	257	return put_user(0, (int *)arg);
70b814ec AC	258	case WDIOC_SETOPTIONS:
	259	if (get_user(options, (int *)arg))
	260	return -EFAULT;
	261
	262	if (options & WDIOS_DISABLECARD) {
8f5585ec	263	sh_wdt_stop(wdt);
70b814ec AC	264	retval = 0;
	265	}
	266
	267	if (options & WDIOS_ENABLECARD) {
8f5585ec	268	sh_wdt_start(wdt);
70b814ec AC	269	retval = 0;
70b814ec AC	270	}
1da177e4	271
70b814ec	272	return retval;
0c06090c	273	case WDIOC_KEEPALIVE:
8f5585ec	274	sh_wdt_keepalive(wdt);
0c06090c WVS	275	return 0;
	276	case WDIOC_SETTIMEOUT:
	277	if (get_user(new_heartbeat, (int *)arg))
	278	return -EFAULT;
	279
	280	if (sh_wdt_set_heartbeat(new_heartbeat))
	281	return -EINVAL;
	282
8f5585ec	283	sh_wdt_keepalive(wdt);
0c06090c WVS	284	/* Fall */
	285	case WDIOC_GETTIMEOUT:
	286	return put_user(heartbeat, (int *)arg);
70b814ec AC	287	default:
	288	return -ENOTTY;
	289	}
1da177e4 LT	290	return 0;
	291	}
	292
1da177e4 LT	293	static int sh_wdt_notify_sys(struct notifier_block *this,
	294	unsigned long code, void *unused)
	295	{
8f5585ec PM	296	struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev);
8f5585ec PM	297
e4c2cfee	298	if (code == SYS_DOWN \|\| code == SYS_HALT)
8f5585ec	299	sh_wdt_stop(wdt);
1da177e4 LT	300
	301	return NOTIFY_DONE;
	302	}
	303
62322d25	304	static const struct file_operations sh_wdt_fops = {
1da177e4 LT	305	.owner = THIS_MODULE,
	306	.llseek = no_llseek,
	307	.write = sh_wdt_write,
70b814ec	308	.unlocked_ioctl = sh_wdt_ioctl,
1da177e4 LT	309	.open = sh_wdt_open,
	310	.release = sh_wdt_close,
	311	};
	312
70b814ec	313	static const struct watchdog_info sh_wdt_info = {
e4c2cfee PM	314	.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \|
e4c2cfee PM	315	WDIOF_MAGICCLOSE,
1da177e4 LT	316	.firmware_version = 1,
	317	.identity = "SH WDT",
	318	};
	319
	320	static struct notifier_block sh_wdt_notifier = {
	321	.notifier_call = sh_wdt_notify_sys,
	322	};
	323
	324	static struct miscdevice sh_wdt_miscdev = {
	325	.minor = WATCHDOG_MINOR,
	326	.name = "watchdog",
	327	.fops = &sh_wdt_fops,
	328	};
	329
8f5585ec	330	static int __devinit sh_wdt_probe(struct platform_device *pdev)
1da177e4	331	{
8f5585ec PM	332	struct sh_wdt *wdt;
8f5585ec PM	333	struct resource *res;
1da177e4 LT	334	int rc;
1da177e4 LT	335
8f5585ec PM	336	/*
	337	* As this driver only covers the global watchdog case, reject
	338	* any attempts to register per-CPU watchdogs.
	339	*/
	340	if (pdev->id != -1)
	341	return -EINVAL;
	342
	343	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	344	if (unlikely(!res))
	345	return -EINVAL;
	346
	347	if (!devm_request_mem_region(&pdev->dev, res->start,
	348	resource_size(res), DRV_NAME))
	349	return -EBUSY;
	350
	351	wdt = devm_kzalloc(&pdev->dev, sizeof(struct sh_wdt), GFP_KERNEL);
	352	if (unlikely(!wdt)) {
	353	rc = -ENOMEM;
	354	goto out_release;
1da177e4 LT	355	}
1da177e4 LT	356
8f5585ec PM	357	wdt->dev = &pdev->dev;
	358
	359	wdt->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
	360	if (unlikely(!wdt->base)) {
	361	rc = -ENXIO;
	362	goto out_err;
1da177e4 LT	363	}
1da177e4 LT	364
1da177e4	365	rc = register_reboot_notifier(&sh_wdt_notifier);
e4c2cfee	366	if (unlikely(rc)) {
8f5585ec	367	dev_err(&pdev->dev,
70b814ec	368	"Can't register reboot notifier (err=%d)\n", rc);
8f5585ec	369	goto out_unmap;
1da177e4 LT	370	}
1da177e4 LT	371
8f5585ec PM	372	sh_wdt_miscdev.parent = wdt->dev;
8f5585ec PM	373
1da177e4	374	rc = misc_register(&sh_wdt_miscdev);
e4c2cfee	375	if (unlikely(rc)) {
8f5585ec	376	dev_err(&pdev->dev,
70b814ec AC	377	"Can't register miscdev on minor=%d (err=%d)\n",
70b814ec AC	378	sh_wdt_miscdev.minor, rc);
8f5585ec	379	goto out_unreg;
1da177e4 LT	380	}
1da177e4 LT	381
8f5585ec PM	382	init_timer(&wdt->timer);
	383	wdt->timer.function = sh_wdt_ping;
	384	wdt->timer.data = (unsigned long)wdt;
	385	wdt->timer.expires = next_ping_period(clock_division_ratio);
	386
	387	platform_set_drvdata(pdev, wdt);
	388	sh_wdt_dev = pdev;
	389
	390	dev_info(&pdev->dev, "initialized.\n");
1da177e4 LT	391
1da177e4 LT	392	return 0;
8f5585ec PM	393
	394	out_unreg:
	395	unregister_reboot_notifier(&sh_wdt_notifier);
	396	out_unmap:
	397	devm_iounmap(&pdev->dev, wdt->base);
	398	out_err:
	399	devm_kfree(&pdev->dev, wdt);
	400	out_release:
	401	devm_release_mem_region(&pdev->dev, res->start, resource_size(res));
	402
	403	return rc;
1da177e4 LT	404	}
1da177e4 LT	405
8f5585ec	406	static int __devexit sh_wdt_remove(struct platform_device *pdev)
1da177e4	407	{
8f5585ec PM	408	struct sh_wdt *wdt = platform_get_drvdata(pdev);
	409	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	410
	411	platform_set_drvdata(pdev, NULL);
	412
1da177e4	413	misc_deregister(&sh_wdt_miscdev);
8f5585ec PM	414
	415	sh_wdt_dev = NULL;
	416
1da177e4	417	unregister_reboot_notifier(&sh_wdt_notifier);
8f5585ec PM	418	devm_release_mem_region(&pdev->dev, res->start, resource_size(res));
	419	devm_iounmap(&pdev->dev, wdt->base);
	420	devm_kfree(&pdev->dev, wdt);
	421
	422	return 0;
	423	}
	424
	425	static struct platform_driver sh_wdt_driver = {
	426	.driver = {
	427	.name = DRV_NAME,
	428	.owner = THIS_MODULE,
	429	},
	430
	431	.probe = sh_wdt_probe,
	432	.remove = __devexit_p(sh_wdt_remove),
	433	};
	434
	435	static int __init sh_wdt_init(void)
	436	{
	437	int rc;
	438
	439	if (unlikely(clock_division_ratio < 0x5 \|\|
	440	clock_division_ratio > 0x7)) {
	441	clock_division_ratio = WTCSR_CKS_4096;
	442
	443	pr_info("%s: divisor must be 0x5<=x<=0x7, using %d\n",
	444	DRV_NAME, clock_division_ratio);
	445	}
	446
	447	rc = sh_wdt_set_heartbeat(heartbeat);
	448	if (unlikely(rc)) {
	449	heartbeat = WATCHDOG_HEARTBEAT;
	450
	451	pr_info("%s: heartbeat value must be 1<=x<=3600, using %d\n",
	452	DRV_NAME, heartbeat);
	453	}
	454
	455	pr_info("%s: configured with heartbeat=%d sec (nowayout=%d)\n",
	456	DRV_NAME, heartbeat, nowayout);
	457
	458	return platform_driver_register(&sh_wdt_driver);
1da177e4 LT	459	}
1da177e4 LT	460
8f5585ec PM	461	static void __exit sh_wdt_exit(void)
	462	{
	463	platform_driver_unregister(&sh_wdt_driver);
	464	}
	465	module_init(sh_wdt_init);
	466	module_exit(sh_wdt_exit);
	467
1da177e4 LT	468	MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
	469	MODULE_DESCRIPTION("SuperH watchdog driver");
	470	MODULE_LICENSE("GPL");
8f5585ec	471	MODULE_ALIAS("platform:" DRV_NAME);
1da177e4 LT	472	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	473
	474	module_param(clock_division_ratio, int, 0);
a77dba7e WVS	475	MODULE_PARM_DESC(clock_division_ratio,
a77dba7e WVS	476	"Clock division ratio. Valid ranges are from 0x5 (1.31ms) "
76550d32	477	"to 0x7 (5.25ms). (default=" __MODULE_STRING(WTCSR_CKS_4096) ")");
1da177e4 LT	478
1da177e4 LT	479	module_param(heartbeat, int, 0);
70b814ec AC	480	MODULE_PARM_DESC(heartbeat,
	481	"Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default="
	482	__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
1da177e4 LT	483
1da177e4 LT	484	module_param(nowayout, int, 0);
70b814ec AC	485	MODULE_PARM_DESC(nowayout,
	486	"Watchdog cannot be stopped once started (default="
	487	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");