[mirror_ubuntu-artful-kernel.git] / drivers / char / watchdog / s3c2410_wdt.c

/* linux/drivers/char/watchdog/s3c2410_wdt.c
 *
 * Copyright (c) 2004 Simtec Electronics
 *	Ben Dooks <ben@simtec.co.uk>
 *
 * S3C2410 Watchdog Timer Support
 *
 * Based on, softdog.c by Alan Cox,
 *     (c) Copyright 1996 Alan Cox <alan@redhat.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Changelog:
 *	05-Oct-2004	BJD	Added semaphore init to stop crashes on open
 *				Fixed tmr_count / wdt_count confusion
 *				Added configurable debug
 *
 *	11-Jan-2005	BJD	Fixed divide-by-2 in timeout code
 *
 *	25-Jan-2005	DA	Added suspend/resume support
 *				Replaced reboot notifier with .shutdown method
 *
 *	10-Mar-2005	LCVR	Changed S3C2410_VA to S3C24XX_VA
*/

#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/platform_device.h>
#include <linux/interrupt.h>
#include <linux/clk.h>

#include <asm/uaccess.h>
#include <asm/io.h>

#include <asm/arch/map.h>

#undef S3C24XX_VA_WATCHDOG
#define S3C24XX_VA_WATCHDOG (0)

#include <asm/arch/regs-watchdog.h>

#define PFX "s3c2410-wdt: "

#define CONFIG_S3C2410_WATCHDOG_ATBOOT		(0)
#define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME	(15)

static int nowayout	= WATCHDOG_NOWAYOUT;
static int tmr_margin	= CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
static int tmr_atboot	= CONFIG_S3C2410_WATCHDOG_ATBOOT;
static int soft_noboot	= 0;
static int debug	= 0;

module_param(tmr_margin,  int, 0);
module_param(tmr_atboot,  int, 0);
module_param(nowayout,    int, 0);
module_param(soft_noboot, int, 0);
module_param(debug,	  int, 0);

MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");

MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));

MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");

MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");


typedef enum close_state {
	CLOSE_STATE_NOT,
	CLOSE_STATE_ALLOW=0x4021
} close_state_t;

static DECLARE_MUTEX(open_lock);

static struct resource	*wdt_mem;
static struct resource	*wdt_irq;
static struct clk	*wdt_clock;
static void __iomem	*wdt_base;
static unsigned int	 wdt_count;
static close_state_t	 allow_close;

/* watchdog control routines */

#define DBG(msg...) do { \
	if (debug) \
		printk(KERN_INFO msg); \
	} while(0)

/* functions */

static int s3c2410wdt_keepalive(void)
{
	writel(wdt_count, wdt_base + S3C2410_WTCNT);
	return 0;
}

static int s3c2410wdt_stop(void)
{
	unsigned long wtcon;

	wtcon = readl(wdt_base + S3C2410_WTCON);
	wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
	writel(wtcon, wdt_base + S3C2410_WTCON);

	return 0;
}

static int s3c2410wdt_start(void)
{
	unsigned long wtcon;

	s3c2410wdt_stop();

	wtcon = readl(wdt_base + S3C2410_WTCON);
	wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;

	if (soft_noboot) {
		wtcon |= S3C2410_WTCON_INTEN;
		wtcon &= ~S3C2410_WTCON_RSTEN;
	} else {
		wtcon &= ~S3C2410_WTCON_INTEN;
		wtcon |= S3C2410_WTCON_RSTEN;
	}

	DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n",
	    __FUNCTION__, wdt_count, wtcon);

	writel(wdt_count, wdt_base + S3C2410_WTDAT);
	writel(wdt_count, wdt_base + S3C2410_WTCNT);
	writel(wtcon, wdt_base + S3C2410_WTCON);

	return 0;
}

static int s3c2410wdt_set_heartbeat(int timeout)
{
	unsigned int freq = clk_get_rate(wdt_clock);
	unsigned int count;
	unsigned int divisor = 1;
	unsigned long wtcon;

	if (timeout < 1)
		return -EINVAL;

	freq /= 128;
	count = timeout * freq;

	DBG("%s: count=%d, timeout=%d, freq=%d\n",
	    __FUNCTION__, count, timeout, freq);

	/* if the count is bigger than the watchdog register,
	   then work out what we need to do (and if) we can
	   actually make this value
	*/

	if (count >= 0x10000) {
		for (divisor = 1; divisor <= 0x100; divisor++) {
			if ((count / divisor) < 0x10000)
				break;
		}

		if ((count / divisor) >= 0x10000) {
			printk(KERN_ERR PFX "timeout %d too big\n", timeout);
			return -EINVAL;
		}
	}

	tmr_margin = timeout;

	DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
	    __FUNCTION__, timeout, divisor, count, count/divisor);

	count /= divisor;
	wdt_count = count;

	/* update the pre-scaler */
	wtcon = readl(wdt_base + S3C2410_WTCON);
	wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
	wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);

	writel(count, wdt_base + S3C2410_WTDAT);
	writel(wtcon, wdt_base + S3C2410_WTCON);

	return 0;
}

/*
 *	/dev/watchdog handling
 */

static int s3c2410wdt_open(struct inode *inode, struct file *file)
{
	if(down_trylock(&open_lock))
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	allow_close = CLOSE_STATE_NOT;

	/* start the timer */
	s3c2410wdt_start();
	return nonseekable_open(inode, file);
}

static int s3c2410wdt_release(struct inode *inode, struct file *file)
{
	/*
	 *	Shut off the timer.
	 * 	Lock it in if it's a module and we set nowayout
	 */

	if (allow_close == CLOSE_STATE_ALLOW) {
		s3c2410wdt_stop();
	} else {
		printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
		s3c2410wdt_keepalive();
	}

	allow_close = CLOSE_STATE_NOT;
	up(&open_lock);
	return 0;
}

static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
				size_t len, loff_t *ppos)
{
	/*
	 *	Refresh the timer.
	 */
	if(len) {
		if (!nowayout) {
			size_t i;

			/* In case it was set long ago */
			allow_close = CLOSE_STATE_NOT;

			for (i = 0; i != len; i++) {
				char c;

				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					allow_close = CLOSE_STATE_ALLOW;
			}
		}

		s3c2410wdt_keepalive();
	}
	return len;
}

#define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE

static struct watchdog_info s3c2410_wdt_ident = {
	.options          =     OPTIONS,
	.firmware_version =	0,
	.identity         =	"S3C2410 Watchdog",
};


static int s3c2410wdt_ioctl(struct inode *inode, struct file *file,
	unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_margin;

	switch (cmd) {
		default:
			return -ENOTTY;

		case WDIOC_GETSUPPORT:
			return copy_to_user(argp, &s3c2410_wdt_ident,
				sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;

		case WDIOC_GETSTATUS:
		case WDIOC_GETBOOTSTATUS:
			return put_user(0, p);

		case WDIOC_KEEPALIVE:
			s3c2410wdt_keepalive();
			return 0;

		case WDIOC_SETTIMEOUT:
			if (get_user(new_margin, p))
				return -EFAULT;

			if (s3c2410wdt_set_heartbeat(new_margin))
				return -EINVAL;

			s3c2410wdt_keepalive();
			return put_user(tmr_margin, p);

		case WDIOC_GETTIMEOUT:
			return put_user(tmr_margin, p);
	}
}

/* kernel interface */

static const struct file_operations s3c2410wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= s3c2410wdt_write,
	.ioctl		= s3c2410wdt_ioctl,
	.open		= s3c2410wdt_open,
	.release	= s3c2410wdt_release,
};

static struct miscdevice s3c2410wdt_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &s3c2410wdt_fops,
};

/* interrupt handler code */

static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
{
	printk(KERN_INFO PFX "Watchdog timer expired!\n");

	s3c2410wdt_keepalive();
	return IRQ_HANDLED;
}
/* device interface */

static int s3c2410wdt_probe(struct platform_device *pdev)
{
	struct resource *res;
	unsigned int wtcon;
	int started = 0;
	int ret;
	int size;

	DBG("%s: probe=%p\n", __FUNCTION__, pdev);

	/* get the memory region for the watchdog timer */

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res == NULL) {
		printk(KERN_INFO PFX "failed to get memory region resouce\n");
		return -ENOENT;
	}

	size = (res->end-res->start)+1;
	wdt_mem = request_mem_region(res->start, size, pdev->name);
	if (wdt_mem == NULL) {
		printk(KERN_INFO PFX "failed to get memory region\n");
		ret = -ENOENT;
		goto err_req;
	}

	wdt_base = ioremap(res->start, size);
	if (wdt_base == 0) {
		printk(KERN_INFO PFX "failed to ioremap() region\n");
		ret = -EINVAL;
		goto err_req;
	}

	DBG("probe: mapped wdt_base=%p\n", wdt_base);

	wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (wdt_irq == NULL) {
		printk(KERN_INFO PFX "failed to get irq resource\n");
		ret = -ENOENT;
		goto err_map;
	}

	ret = request_irq(wdt_irq->start, s3c2410wdt_irq, 0, pdev->name, pdev);
	if (ret != 0) {
		printk(KERN_INFO PFX "failed to install irq (%d)\n", ret);
		goto err_map;
	}

	wdt_clock = clk_get(&pdev->dev, "watchdog");
	if (IS_ERR(wdt_clock)) {
		printk(KERN_INFO PFX "failed to find watchdog clock source\n");
		ret = PTR_ERR(wdt_clock);
		goto err_irq;
	}

	clk_enable(wdt_clock);

	/* see if we can actually set the requested timer margin, and if
	 * not, try the default value */

	if (s3c2410wdt_set_heartbeat(tmr_margin)) {
		started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);

		if (started == 0) {
			printk(KERN_INFO PFX "tmr_margin value out of range, default %d used\n",
			       CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
		} else {
			printk(KERN_INFO PFX "default timer value is out of range, cannot start\n");
		}
	}

	ret = misc_register(&s3c2410wdt_miscdev);
	if (ret) {
		printk (KERN_ERR PFX "cannot register miscdev on minor=%d (%d)\n",
			WATCHDOG_MINOR, ret);
		goto err_clk;
	}

	if (tmr_atboot && started == 0) {
		printk(KERN_INFO PFX "Starting Watchdog Timer\n");
		s3c2410wdt_start();
	} else if (!tmr_atboot) {
		/* if we're not enabling the watchdog, then ensure it is
		 * disabled if it has been left running from the bootloader
		 * or other source */

		s3c2410wdt_stop();
	}

	/* print out a statement of readiness */

	wtcon = readl(wdt_base + S3C2410_WTCON);

	dev_info(&pdev->dev,
		 "watchdog %sactive, reset %sabled, irq %sabled\n",
		 (wtcon & S3C2410_WTCON_ENABLE) ?  "" : "in",
		 (wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
		 (wtcon & S3C2410_WTCON_INTEN) ? "" : "en");

	return 0;

 err_clk:
	clk_disable(wdt_clock);
	clk_put(wdt_clock);

 err_irq:
	free_irq(wdt_irq->start, pdev);

 err_map:
	iounmap(wdt_base);

 err_req:
	release_resource(wdt_mem);
	kfree(wdt_mem);

	return ret;
}

static int s3c2410wdt_remove(struct platform_device *dev)
{
	release_resource(wdt_mem);
	kfree(wdt_mem);
	wdt_mem = NULL;

	free_irq(wdt_irq->start, dev);
	wdt_irq = NULL;

	clk_disable(wdt_clock);
	clk_put(wdt_clock);
	wdt_clock = NULL;

	iounmap(wdt_base);
	misc_deregister(&s3c2410wdt_miscdev);
	return 0;
}

static void s3c2410wdt_shutdown(struct platform_device *dev)
{
	s3c2410wdt_stop();	
}

#ifdef CONFIG_PM

static unsigned long wtcon_save;
static unsigned long wtdat_save;

static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state)
{
	/* Save watchdog state, and turn it off. */
	wtcon_save = readl(wdt_base + S3C2410_WTCON);
	wtdat_save = readl(wdt_base + S3C2410_WTDAT);

	/* Note that WTCNT doesn't need to be saved. */
	s3c2410wdt_stop();

	return 0;
}

static int s3c2410wdt_resume(struct platform_device *dev)
{
	/* Restore watchdog state. */

	writel(wtdat_save, wdt_base + S3C2410_WTDAT);
	writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */
	writel(wtcon_save, wdt_base + S3C2410_WTCON);

	printk(KERN_INFO PFX "watchdog %sabled\n",
	       (wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");

	return 0;
}

#else
#define s3c2410wdt_suspend NULL
#define s3c2410wdt_resume  NULL
#endif /* CONFIG_PM */


static struct platform_driver s3c2410wdt_driver = {
	.probe		= s3c2410wdt_probe,
	.remove		= s3c2410wdt_remove,
	.shutdown	= s3c2410wdt_shutdown,
	.suspend	= s3c2410wdt_suspend,
	.resume		= s3c2410wdt_resume,
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= "s3c2410-wdt",
	},
};


static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";

static int __init watchdog_init(void)
{
	printk(banner);
	return platform_driver_register(&s3c2410wdt_driver);
}

static void __exit watchdog_exit(void)
{
	platform_driver_unregister(&s3c2410wdt_driver);
}

module_init(watchdog_init);
module_exit(watchdog_exit);

MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
	      "Dimitry Andric <dimitry.andric@tomtom.com>");
MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
1da177e4 LT	1	/* linux/drivers/char/watchdog/s3c2410_wdt.c
	2	*
	3	* Copyright (c) 2004 Simtec Electronics
	4	* Ben Dooks <ben@simtec.co.uk>
	5	*
	6	* S3C2410 Watchdog Timer Support
	7	*
	8	* Based on, softdog.c by Alan Cox,
	9	* (c) Copyright 1996 Alan Cox <alan@redhat.com>
	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License as published by
	13	* the Free Software Foundation; either version 2 of the License, or
	14	* (at your option) any later version.
	15	*
	16	* This program is distributed in the hope that it will be useful,
	17	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	* GNU General Public License for more details.
	20	*
	21	* You should have received a copy of the GNU General Public License
	22	* along with this program; if not, write to the Free Software
	23	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	24	*
	25	* Changelog:
	26	* 05-Oct-2004 BJD Added semaphore init to stop crashes on open
	27	* Fixed tmr_count / wdt_count confusion
	28	* Added configurable debug
	29	*
af4bb822 BD	30	* 11-Jan-2005 BJD Fixed divide-by-2 in timeout code
	31	*
	32	* 25-Jan-2005 DA Added suspend/resume support
94f1e9f3	33	* Replaced reboot notifier with .shutdown method
1da177e4 LT	34	*
	35	* 10-Mar-2005 LCVR Changed S3C2410_VA to S3C24XX_VA
	36	*/
	37
	38	#include <linux/module.h>
	39	#include <linux/moduleparam.h>
1da177e4 LT	40	#include <linux/types.h>
	41	#include <linux/timer.h>
	42	#include <linux/miscdevice.h>
	43	#include <linux/watchdog.h>
	44	#include <linux/fs.h>
1da177e4	45	#include <linux/init.h>
d052d1be	46	#include <linux/platform_device.h>
1da177e4	47	#include <linux/interrupt.h>
f8ce2547	48	#include <linux/clk.h>
1da177e4 LT	49
	50	#include <asm/uaccess.h>
	51	#include <asm/io.h>
	52
	53	#include <asm/arch/map.h>
1da177e4 LT	54
	55	#undef S3C24XX_VA_WATCHDOG
	56	#define S3C24XX_VA_WATCHDOG (0)
	57
	58	#include <asm/arch/regs-watchdog.h>
	59
	60	#define PFX "s3c2410-wdt: "
	61
	62	#define CONFIG_S3C2410_WATCHDOG_ATBOOT (0)
	63	#define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15)
	64
25ff3780	65	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4 LT	66	static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
	67	static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT;
	68	static int soft_noboot = 0;
	69	static int debug = 0;
	70
	71	module_param(tmr_margin, int, 0);
	72	module_param(tmr_atboot, int, 0);
	73	module_param(nowayout, int, 0);
	74	module_param(soft_noboot, int, 0);
	75	module_param(debug, int, 0);
	76
	77	MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
	78
	79	MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
	80
bffda5c8	81	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4 LT	82
	83	MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
	84
	85	MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
	86
	87
	88	typedef enum close_state {
	89	CLOSE_STATE_NOT,
	90	CLOSE_STATE_ALLOW=0x4021
	91	} close_state_t;
	92
	93	static DECLARE_MUTEX(open_lock);
	94
	95	static struct resource *wdt_mem;
	96	static struct resource *wdt_irq;
	97	static struct clk *wdt_clock;
	98	static void __iomem *wdt_base;
	99	static unsigned int wdt_count;
	100	static close_state_t allow_close;
	101
	102	/* watchdog control routines */
	103
	104	#define DBG(msg...) do { \
	105	if (debug) \
	106	printk(KERN_INFO msg); \
	107	} while(0)
	108
	109	/* functions */
	110
	111	static int s3c2410wdt_keepalive(void)
	112	{
	113	writel(wdt_count, wdt_base + S3C2410_WTCNT);
	114	return 0;
	115	}
	116
	117	static int s3c2410wdt_stop(void)
	118	{
	119	unsigned long wtcon;
	120
	121	wtcon = readl(wdt_base + S3C2410_WTCON);
	122	wtcon &= ~(S3C2410_WTCON_ENABLE \| S3C2410_WTCON_RSTEN);
	123	writel(wtcon, wdt_base + S3C2410_WTCON);
	124
	125	return 0;
	126	}
	127
	128	static int s3c2410wdt_start(void)
	129	{
	130	unsigned long wtcon;
	131
	132	s3c2410wdt_stop();
	133
	134	wtcon = readl(wdt_base + S3C2410_WTCON);
	135	wtcon \|= S3C2410_WTCON_ENABLE \| S3C2410_WTCON_DIV128;
	136
	137	if (soft_noboot) {
	138	wtcon \|= S3C2410_WTCON_INTEN;
	139	wtcon &= ~S3C2410_WTCON_RSTEN;
	140	} else {
	141	wtcon &= ~S3C2410_WTCON_INTEN;
	142	wtcon \|= S3C2410_WTCON_RSTEN;
	143	}
	144
	145	DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n",
146	__FUNCTION__, wdt_count, wtcon);
147
148	writel(wdt_count, wdt_base + S3C2410_WTDAT);
149	writel(wdt_count, wdt_base + S3C2410_WTCNT);
150	writel(wtcon, wdt_base + S3C2410_WTCON);
151
152	return 0;
153	}
154
155	static int s3c2410wdt_set_heartbeat(int timeout)
156	{
157	unsigned int freq = clk_get_rate(wdt_clock);
158	unsigned int count;
159	unsigned int divisor = 1;
160	unsigned long wtcon;
161
162	if (timeout < 1)
163	return -EINVAL;
164
165	freq /= 128;
166	count = timeout * freq;
167
168	DBG("%s: count=%d, timeout=%d, freq=%d\n",
169	__FUNCTION__, count, timeout, freq);
170
171	/* if the count is bigger than the watchdog register,
172	then work out what we need to do (and if) we can
173	actually make this value
174	*/
175
176	if (count >= 0x10000) {
177	for (divisor = 1; divisor <= 0x100; divisor++) {
178	if ((count / divisor) < 0x10000)
179	break;
180	}
181
182	if ((count / divisor) >= 0x10000) {
183	printk(KERN_ERR PFX "timeout %d too big\n", timeout);
184	return -EINVAL;
185	}
186	}
187
188	tmr_margin = timeout;
189
190	DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
191	__FUNCTION__, timeout, divisor, count, count/divisor);
192
193	count /= divisor;
194	wdt_count = count;
195
196	/* update the pre-scaler */
197	wtcon = readl(wdt_base + S3C2410_WTCON);
198	wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
199	wtcon \|= S3C2410_WTCON_PRESCALE(divisor-1);
200
201	writel(count, wdt_base + S3C2410_WTDAT);
202	writel(wtcon, wdt_base + S3C2410_WTCON);
203
204	return 0;
205	}
206
207	/*
208	* /dev/watchdog handling
209	*/
210
211	static int s3c2410wdt_open(struct inode inode, struct file file)
212	{
213	if(down_trylock(&open_lock))
214	return -EBUSY;
215
25ff3780	216	if (nowayout)
1da177e4	217	__module_get(THIS_MODULE);
25ff3780 BD	218
25ff3780 BD	219	allow_close = CLOSE_STATE_NOT;
1da177e4 LT	220
	221	/* start the timer */
	222	s3c2410wdt_start();
	223	return nonseekable_open(inode, file);
	224	}
	225
	226	static int s3c2410wdt_release(struct inode inode, struct file file)
	227	{
	228	/*
	229	* Shut off the timer.
	230	* Lock it in if it's a module and we set nowayout
	231	*/
25ff3780	232
1da177e4 LT	233	if (allow_close == CLOSE_STATE_ALLOW) {
	234	s3c2410wdt_stop();
	235	} else {
	236	printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
	237	s3c2410wdt_keepalive();
	238	}
	239
	240	allow_close = CLOSE_STATE_NOT;
	241	up(&open_lock);
	242	return 0;
	243	}
	244
	245	static ssize_t s3c2410wdt_write(struct file file, const char __user data,
	246	size_t len, loff_t *ppos)
	247	{
	248	/*
	249	* Refresh the timer.
	250	*/
	251	if(len) {
	252	if (!nowayout) {
	253	size_t i;
	254
	255	/* In case it was set long ago */
	256	allow_close = CLOSE_STATE_NOT;
	257
	258	for (i = 0; i != len; i++) {
	259	char c;
	260
	261	if (get_user(c, data + i))
	262	return -EFAULT;
	263	if (c == 'V')
	264	allow_close = CLOSE_STATE_ALLOW;
	265	}
	266	}
	267
	268	s3c2410wdt_keepalive();
	269	}
	270	return len;
	271	}
	272
	273	#define OPTIONS WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE
	274
	275	static struct watchdog_info s3c2410_wdt_ident = {
	276	.options = OPTIONS,
	277	.firmware_version = 0,
	278	.identity = "S3C2410 Watchdog",
	279	};
	280
	281
	282	static int s3c2410wdt_ioctl(struct inode inode, struct file file,
	283	unsigned int cmd, unsigned long arg)
	284	{
	285	void __user argp = (void __user )arg;
	286	int __user *p = argp;
	287	int new_margin;
	288
	289	switch (cmd) {
	290	default:
795b89d2	291	return -ENOTTY;
1da177e4 LT	292
	293	case WDIOC_GETSUPPORT:
	294	return copy_to_user(argp, &s3c2410_wdt_ident,
	295	sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
	296
	297	case WDIOC_GETSTATUS:
	298	case WDIOC_GETBOOTSTATUS:
	299	return put_user(0, p);
	300
	301	case WDIOC_KEEPALIVE:
	302	s3c2410wdt_keepalive();
	303	return 0;
	304
	305	case WDIOC_SETTIMEOUT:
	306	if (get_user(new_margin, p))
	307	return -EFAULT;
	308
	309	if (s3c2410wdt_set_heartbeat(new_margin))
	310	return -EINVAL;
	311
	312	s3c2410wdt_keepalive();
	313	return put_user(tmr_margin, p);
	314
	315	case WDIOC_GETTIMEOUT:
	316	return put_user(tmr_margin, p);
	317	}
	318	}
	319
1da177e4 LT	320	/* kernel interface */
1da177e4 LT	321
62322d25	322	static const struct file_operations s3c2410wdt_fops = {
1da177e4 LT	323	.owner = THIS_MODULE,
	324	.llseek = no_llseek,
	325	.write = s3c2410wdt_write,
	326	.ioctl = s3c2410wdt_ioctl,
	327	.open = s3c2410wdt_open,
	328	.release = s3c2410wdt_release,
	329	};
	330
	331	static struct miscdevice s3c2410wdt_miscdev = {
	332	.minor = WATCHDOG_MINOR,
	333	.name = "watchdog",
	334	.fops = &s3c2410wdt_fops,
	335	};
	336
1da177e4 LT	337	/* interrupt handler code */
1da177e4 LT	338
7d12e780	339	static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
1da177e4 LT	340	{
	341	printk(KERN_INFO PFX "Watchdog timer expired!\n");
	342
	343	s3c2410wdt_keepalive();
	344	return IRQ_HANDLED;
	345	}
	346	/* device interface */
	347
3ae5eaec	348	static int s3c2410wdt_probe(struct platform_device *pdev)
1da177e4	349	{
1da177e4	350	struct resource *res;
46b814d6	351	unsigned int wtcon;
1da177e4 LT	352	int started = 0;
	353	int ret;
	354	int size;
	355
3ae5eaec	356	DBG("%s: probe=%p\n", __FUNCTION__, pdev);
1da177e4 LT	357
	358	/* get the memory region for the watchdog timer */
	359
	360	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	361	if (res == NULL) {
	362	printk(KERN_INFO PFX "failed to get memory region resouce\n");
	363	return -ENOENT;
	364	}
	365
	366	size = (res->end-res->start)+1;
	367	wdt_mem = request_mem_region(res->start, size, pdev->name);
	368	if (wdt_mem == NULL) {
	369	printk(KERN_INFO PFX "failed to get memory region\n");
0b6dd8a6 BD	370	ret = -ENOENT;
0b6dd8a6 BD	371	goto err_req;
1da177e4 LT	372	}
	373
	374	wdt_base = ioremap(res->start, size);
	375	if (wdt_base == 0) {
	376	printk(KERN_INFO PFX "failed to ioremap() region\n");
0b6dd8a6 BD	377	ret = -EINVAL;
0b6dd8a6 BD	378	goto err_req;
1da177e4 LT	379	}
	380
	381	DBG("probe: mapped wdt_base=%p\n", wdt_base);
	382
62be0741 AP	383	wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
62be0741 AP	384	if (wdt_irq == NULL) {
1da177e4	385	printk(KERN_INFO PFX "failed to get irq resource\n");
0b6dd8a6 BD	386	ret = -ENOENT;
0b6dd8a6 BD	387	goto err_map;
1da177e4 LT	388	}
1da177e4 LT	389
62be0741	390	ret = request_irq(wdt_irq->start, s3c2410wdt_irq, 0, pdev->name, pdev);
1da177e4 LT	391	if (ret != 0) {
1da177e4 LT	392	printk(KERN_INFO PFX "failed to install irq (%d)\n", ret);
0b6dd8a6	393	goto err_map;
1da177e4 LT	394	}
1da177e4 LT	395
3ae5eaec	396	wdt_clock = clk_get(&pdev->dev, "watchdog");
9cd44619	397	if (IS_ERR(wdt_clock)) {
1da177e4	398	printk(KERN_INFO PFX "failed to find watchdog clock source\n");
9cd44619	399	ret = PTR_ERR(wdt_clock);
0b6dd8a6	400	goto err_irq;
1da177e4 LT	401	}
1da177e4 LT	402
1da177e4 LT	403	clk_enable(wdt_clock);
	404
	405	/* see if we can actually set the requested timer margin, and if
	406	* not, try the default value */
	407
	408	if (s3c2410wdt_set_heartbeat(tmr_margin)) {
	409	started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
	410
	411	if (started == 0) {
	412	printk(KERN_INFO PFX "tmr_margin value out of range, default %d used\n",
	413	CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
	414	} else {
	415	printk(KERN_INFO PFX "default timer value is out of range, cannot start\n");
	416	}
	417	}
	418
1da177e4 LT	419	ret = misc_register(&s3c2410wdt_miscdev);
	420	if (ret) {
	421	printk (KERN_ERR PFX "cannot register miscdev on minor=%d (%d)\n",
	422	WATCHDOG_MINOR, ret);
0b6dd8a6	423	goto err_clk;
1da177e4 LT	424	}
	425
	426	if (tmr_atboot && started == 0) {
	427	printk(KERN_INFO PFX "Starting Watchdog Timer\n");
	428	s3c2410wdt_start();
655516c8 BD	429	} else if (!tmr_atboot) {
	430	/* if we're not enabling the watchdog, then ensure it is
	431	* disabled if it has been left running from the bootloader
	432	* or other source */
	433
	434	s3c2410wdt_stop();
1da177e4 LT	435	}
1da177e4 LT	436
46b814d6 BD	437	/* print out a statement of readiness */
	438
	439	wtcon = readl(wdt_base + S3C2410_WTCON);
	440
	441	dev_info(&pdev->dev,
	442	"watchdog %sactive, reset %sabled, irq %sabled\n",
	443	(wtcon & S3C2410_WTCON_ENABLE) ? "" : "in",
	444	(wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
	445	(wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
	446
1da177e4	447	return 0;
0b6dd8a6 BD	448
	449	err_clk:
	450	clk_disable(wdt_clock);
	451	clk_put(wdt_clock);
	452
	453	err_irq:
	454	free_irq(wdt_irq->start, pdev);
	455
	456	err_map:
	457	iounmap(wdt_base);
	458
	459	err_req:
	460	release_resource(wdt_mem);
	461	kfree(wdt_mem);
	462
	463	return ret;
1da177e4 LT	464	}
1da177e4 LT	465
3ae5eaec	466	static int s3c2410wdt_remove(struct platform_device *dev)
1da177e4	467	{
0b6dd8a6 BD	468	release_resource(wdt_mem);
	469	kfree(wdt_mem);
	470	wdt_mem = NULL;
1da177e4	471
0b6dd8a6 BD	472	free_irq(wdt_irq->start, dev);
0b6dd8a6 BD	473	wdt_irq = NULL;
1da177e4	474
0b6dd8a6 BD	475	clk_disable(wdt_clock);
	476	clk_put(wdt_clock);
	477	wdt_clock = NULL;
1da177e4	478
e34477e9	479	iounmap(wdt_base);
1da177e4 LT	480	misc_deregister(&s3c2410wdt_miscdev);
	481	return 0;
	482	}
	483
3ae5eaec	484	static void s3c2410wdt_shutdown(struct platform_device *dev)
94f1e9f3 BD	485	{
	486	s3c2410wdt_stop();
	487	}
	488
af4bb822 BD	489	#ifdef CONFIG_PM
	490
	491	static unsigned long wtcon_save;
	492	static unsigned long wtdat_save;
	493
3ae5eaec	494	static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state)
af4bb822	495	{
9480e307 RK	496	/* Save watchdog state, and turn it off. */
	497	wtcon_save = readl(wdt_base + S3C2410_WTCON);
	498	wtdat_save = readl(wdt_base + S3C2410_WTDAT);
af4bb822	499
9480e307 RK	500	/* Note that WTCNT doesn't need to be saved. */
9480e307 RK	501	s3c2410wdt_stop();
af4bb822 BD	502
	503	return 0;
	504	}
	505
3ae5eaec	506	static int s3c2410wdt_resume(struct platform_device *dev)
af4bb822	507	{
9480e307	508	/* Restore watchdog state. */
af4bb822	509
9480e307 RK	510	writel(wtdat_save, wdt_base + S3C2410_WTDAT);
	511	writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */
	512	writel(wtcon_save, wdt_base + S3C2410_WTCON);
af4bb822	513
9480e307 RK	514	printk(KERN_INFO PFX "watchdog %sabled\n",
9480e307 RK	515	(wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
af4bb822 BD	516
	517	return 0;
	518	}
	519
	520	#else
	521	#define s3c2410wdt_suspend NULL
	522	#define s3c2410wdt_resume NULL
	523	#endif /* CONFIG_PM */
	524
	525
3ae5eaec	526	static struct platform_driver s3c2410wdt_driver = {
1da177e4 LT	527	.probe = s3c2410wdt_probe,
1da177e4 LT	528	.remove = s3c2410wdt_remove,
94f1e9f3	529	.shutdown = s3c2410wdt_shutdown,
af4bb822 BD	530	.suspend = s3c2410wdt_suspend,
af4bb822 BD	531	.resume = s3c2410wdt_resume,
3ae5eaec RK	532	.driver = {
	533	.owner = THIS_MODULE,
	534	.name = "s3c2410-wdt",
	535	},
1da177e4 LT	536	};
	537
	538
1da177e4 LT	539	static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
	540
	541	static int __init watchdog_init(void)
	542	{
	543	printk(banner);
3ae5eaec	544	return platform_driver_register(&s3c2410wdt_driver);
1da177e4 LT	545	}
	546
	547	static void __exit watchdog_exit(void)
	548	{
3ae5eaec	549	platform_driver_unregister(&s3c2410wdt_driver);
1da177e4 LT	550	}
	551
	552	module_init(watchdog_init);
	553	module_exit(watchdog_exit);
	554
af4bb822 BD	555	MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
af4bb822 BD	556	"Dimitry Andric <dimitry.andric@tomtom.com>");
1da177e4 LT	557	MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
	558	MODULE_LICENSE("GPL");
	559	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);