Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 41dc8b72 authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
Browse files

s3c2410_wdt watchdog driver: Locking and coding style 



Kill off use of semaphores.
Fix ioctl races and locking holes.

From: Alan Cox <alan@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d6547378

drivers/watchdog/s3c2410_wdt.c

+80 −68
Original line number Diff line number Diff line
@@ -46,9 +46,8 @@ 
#include <linux/platform_device.h>

#include <linux/interrupt.h>

#include <linux/clk.h>



#include <asm/uaccess.h>

#include <asm/io.h>

#include <linux/uaccess.h>

#include <linux/io.h>



#include <asm/arch/map.h>
@@ -65,8 +64,8 @@ 
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;

static int soft_noboot;

static int debug;



module_param(tmr_margin,  int, 0);

module_param(tmr_atboot,  int, 0);
@@ -74,14 +73,14 @@ 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(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)");
@@ -90,8 +89,7 @@ typedef enum close_state { 
	CLOSE_STATE_ALLOW = 0x4021

} close_state_t;



static DECLARE_MUTEX(open_lock);



static unsigned long open_lock;

static struct device    *wdt_dev;	/* platform device attached to */

static struct resource	*wdt_mem;

static struct resource	*wdt_irq;
@@ -99,6 +97,7 @@ static struct clk *wdt_clock; 
static void __iomem	*wdt_base;

static unsigned int	 wdt_count;

static close_state_t	 allow_close;

static DEFINE_SPINLOCK(wdt_lock);



/* watchdog control routines */
@@ -109,28 +108,47 @@ static close_state_t allow_close; 


/* functions */



static int s3c2410wdt_keepalive(void)

static void s3c2410wdt_keepalive(void)

{

	spin_lock(&wdt_lock);

	writel(wdt_count, wdt_base + S3C2410_WTCNT);

	return 0;

	spin_unlock(&wdt_lock);

}



static int s3c2410wdt_stop(void)

static void __s3c2410wdt_stop(void)

{

	unsigned long wtcon;



	spin_lock(&wdt_lock);

	wtcon = readl(wdt_base + S3C2410_WTCON);

	wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);

	writel(wtcon, wdt_base + S3C2410_WTCON);

	spin_unlock(&wdt_lock);

}



	return 0;

static void __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);

}



static int s3c2410wdt_start(void)

static void s3c2410wdt_stop(void)

{

	spin_lock(&wdt_lock);

	__s3c2410wdt_stop();

	spin_unlock(&wdt_lock);

}



static void s3c2410wdt_start(void)

{

	unsigned long wtcon;



	s3c2410wdt_stop();

	spin_lock(&wdt_lock);



	__s3c2410wdt_stop();



	wtcon = readl(wdt_base + S3C2410_WTCON);

	wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
@@ -149,6 +167,7 @@ static int s3c2410wdt_start(void) 
	writel(wdt_count, wdt_base + S3C2410_WTDAT);

	writel(wdt_count, wdt_base + S3C2410_WTCNT);

	writel(wtcon, wdt_base + S3C2410_WTCON);

	spin_unlock(&wdt_lock);



	return 0;

}
@@ -211,7 +230,7 @@ static int s3c2410wdt_set_heartbeat(int timeout) 


static int s3c2410wdt_open(struct inode *inode, struct file *file)

{

	if(down_trylock(&open_lock))

	if (test_and_set_bit(0, &open_lock))

		return -EBUSY;



	if (nowayout)
@@ -231,15 +250,14 @@ static int s3c2410wdt_release(struct inode *inode, struct file *file) 
	 * 	Lock it in if it's a module and we set nowayout

	 */



	if (allow_close == CLOSE_STATE_ALLOW) {

	if (allow_close == CLOSE_STATE_ALLOW)

		s3c2410wdt_stop();

	} else {

	else {

		dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n");

		s3c2410wdt_keepalive();

	}



	allow_close = CLOSE_STATE_NOT;

	up(&open_lock);

	clear_bit(0, &open_lock);

	return 0;

}
@@ -265,7 +283,6 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data, 
					allow_close = CLOSE_STATE_ALLOW;

			}

		}



		s3c2410wdt_keepalive();

	}

	return len;
@@ -273,15 +290,15 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data, 


#define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE



static struct watchdog_info s3c2410_wdt_ident = {

static const 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)

static long s3c2410wdt_ioctl(struct file *file,	unsigned int cmd,

							unsigned long arg)

{

	void __user *argp = (void __user *)arg;

	int __user *p = argp;
@@ -290,29 +307,22 @@ static int s3c2410wdt_ioctl(struct inode *inode, struct file *file, 
	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);

	}
@@ -324,7 +334,7 @@ static const struct file_operations s3c2410wdt_fops = { 
	.owner		= THIS_MODULE,

	.llseek		= no_llseek,

	.write		= s3c2410wdt_write,

	.ioctl		= s3c2410wdt_ioctl,

	.unlocked_ioctl	= s3c2410wdt_ioctl,

	.open		= s3c2410wdt_open,

	.release	= s3c2410wdt_release,

};
@@ -411,15 +421,16 @@ static int s3c2410wdt_probe(struct platform_device *pdev) 
	 * not, try the default value */



	if (s3c2410wdt_set_heartbeat(tmr_margin)) {

		started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);

		started = s3c2410wdt_set_heartbeat(

					CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);



		if (started == 0) {

			dev_info(dev,"tmr_margin value out of range, default %d used\n",

		if (started == 0)

			dev_info(dev,

			   "tmr_margin value out of range, default %d used\n",

			       CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);

		} else {

		else

			dev_info(dev, "default timer value is out of range, cannot start\n");

	}

	}



	ret = misc_register(&s3c2410wdt_miscdev);

	if (ret) {
@@ -540,7 +551,8 @@ static struct platform_driver s3c2410wdt_driver = { 
};





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

static char banner[] __initdata =

	KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";



static int __init watchdog_init(void)

{