/* 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/config.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=CONFIG_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);	} else {		allow_close = CLOSE_STATE_ALLOW;	}	/* 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_MAGICCLOSEstatic 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 -ENOIOCTLCMD;		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 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,				  struct pt_regs *regs){	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;	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");		return -ENOENT;	}	wdt_base = ioremap(res->start, size);	if (wdt_base == 0) {		printk(KERN_INFO PFX "failed to ioremap() region\n");		return -EINVAL;	}	DBG("probe: mapped wdt_base=%p\n", wdt_base);	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);	if (res == NULL) {		printk(KERN_INFO PFX "failed to get irq resource\n");		return -ENOENT;	}	ret = request_irq(res->start, s3c2410wdt_irq, 0, pdev->name, pdev);	if (ret != 0) {		printk(KERN_INFO PFX "failed to install irq (%d)\n", ret);		return ret;	}	wdt_clock = clk_get(&pdev->dev, "watchdog");	if (wdt_clock == NULL) {		printk(KERN_INFO PFX "failed to find watchdog clock source\n");		return -ENOENT;	}	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);		return ret;	}	if (tmr_atboot && started == 0) {		printk(KERN_INFO PFX "Starting Watchdog Timer\n");		s3c2410wdt_start();	}	return 0;}static int s3c2410wdt_remove(struct platform_device *dev){	if (wdt_mem != NULL) {		release_resource(wdt_mem);		kfree(wdt_mem);		wdt_mem = NULL;	}	if (wdt_irq != NULL) {		free_irq(wdt_irq->start, dev);		wdt_irq = NULL;	}	if (wdt_clock != NULL) {		clk_disable(wdt_clock);		clk_put(wdt_clock);		wdt_clock = NULL;	}	misc_deregister(&s3c2410wdt_miscdev);	return 0;}static void s3c2410wdt_shutdown(struct platform_device *dev){	s3c2410wdt_stop();	}#ifdef CONFIG_PMstatic 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);