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Commit 41dc8b72 authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
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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
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Showing with 80 additions and 68 deletions
drivers/watchdog/s3c2410_wdt.c
View file @ 41dc8b72
......@@ -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);
......@@ -74,24 +73,23 @@ 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)");
typedef enum close_state {
CLOSE_STATE_NOT,
CLOSE_STATE_ALLOW=0x4021
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;
......@@ -99,38 +97,58 @@ 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 */
#define DBG(msg...) do { \
if (debug) \
printk(KERN_INFO msg); \
} while(0)
} while (0)
/* 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 void s3c2410wdt_stop(void)
{
spin_lock(&wdt_lock);
__s3c2410wdt_stop();
spin_unlock(&wdt_lock);
}
static int s3c2410wdt_start(void)
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;
}
......@@ -249,7 +267,7 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
/*
* Refresh the timer.
*/
if(len) {
if (len) {
if (!nowayout) {
size_t i;
......@@ -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;
......@@ -273,48 +290,41 @@ 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;
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);
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,
};
......@@ -411,14 +421,15 @@ 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);
......@@ -447,7 +458,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
(wtcon & S3C2410_WTCON_ENABLE) ? "" : "in",
(wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
(wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
return 0;
err_clk:
......@@ -487,7 +498,7 @@ static int s3c2410wdt_remove(struct platform_device *dev)
static void s3c2410wdt_shutdown(struct platform_device *dev)
{
s3c2410wdt_stop();
s3c2410wdt_stop();
}
#ifdef CONFIG_PM
......@@ -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)
{
......
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