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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>hifive-unleashed-5.1
Alan Cox
Linus Torvalds
parent
d6547378df
commit
41dc8b72e3
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@ -46,9 +46,8 @@
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#include <linux/platform_device.h>
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#include <linux/interrupt.h>
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#include <linux/clk.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <asm/arch/map.h>
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@ -65,8 +64,8 @@
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static int nowayout = WATCHDOG_NOWAYOUT;
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static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
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static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT;
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static int soft_noboot = 0;
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static int debug = 0;
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static int soft_noboot;
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static int debug;
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module_param(tmr_margin, int, 0);
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module_param(tmr_atboot, int, 0);
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@ -74,24 +73,23 @@ module_param(nowayout, int, 0);
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module_param(soft_noboot, int, 0);
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module_param(debug, int, 0);
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MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
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MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default="
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__MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
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MODULE_PARM_DESC(tmr_atboot,
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"Watchdog is started at boot time if set to 1, default="
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__MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
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MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
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typedef enum close_state {
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CLOSE_STATE_NOT,
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CLOSE_STATE_ALLOW=0x4021
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CLOSE_STATE_ALLOW = 0x4021
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} close_state_t;
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static DECLARE_MUTEX(open_lock);
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static unsigned long open_lock;
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static struct device *wdt_dev; /* platform device attached to */
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static struct resource *wdt_mem;
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static struct resource *wdt_irq;
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@ -99,38 +97,58 @@ static struct clk *wdt_clock;
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static void __iomem *wdt_base;
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static unsigned int wdt_count;
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static close_state_t allow_close;
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static DEFINE_SPINLOCK(wdt_lock);
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/* watchdog control routines */
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#define DBG(msg...) do { \
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if (debug) \
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printk(KERN_INFO msg); \
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} while(0)
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} while (0)
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/* functions */
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static int s3c2410wdt_keepalive(void)
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static void s3c2410wdt_keepalive(void)
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{
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spin_lock(&wdt_lock);
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writel(wdt_count, wdt_base + S3C2410_WTCNT);
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return 0;
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spin_unlock(&wdt_lock);
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}
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static int s3c2410wdt_stop(void)
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static void __s3c2410wdt_stop(void)
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{
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unsigned long wtcon;
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spin_lock(&wdt_lock);
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wtcon = readl(wdt_base + S3C2410_WTCON);
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wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
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writel(wtcon, wdt_base + S3C2410_WTCON);
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spin_unlock(&wdt_lock);
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}
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static void __s3c2410wdt_stop(void)
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{
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unsigned long wtcon;
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wtcon = readl(wdt_base + S3C2410_WTCON);
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wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
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writel(wtcon, wdt_base + S3C2410_WTCON);
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return 0;
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}
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static int s3c2410wdt_start(void)
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static void s3c2410wdt_stop(void)
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{
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spin_lock(&wdt_lock);
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__s3c2410wdt_stop();
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spin_unlock(&wdt_lock);
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}
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static void s3c2410wdt_start(void)
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{
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unsigned long wtcon;
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s3c2410wdt_stop();
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spin_lock(&wdt_lock);
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__s3c2410wdt_stop();
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wtcon = readl(wdt_base + S3C2410_WTCON);
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wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
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@ -149,6 +167,7 @@ static int s3c2410wdt_start(void)
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writel(wdt_count, wdt_base + S3C2410_WTDAT);
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writel(wdt_count, wdt_base + S3C2410_WTCNT);
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writel(wtcon, wdt_base + S3C2410_WTCON);
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spin_unlock(&wdt_lock);
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return 0;
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}
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@ -211,7 +230,7 @@ static int s3c2410wdt_set_heartbeat(int timeout)
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static int s3c2410wdt_open(struct inode *inode, struct file *file)
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{
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if(down_trylock(&open_lock))
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if (test_and_set_bit(0, &open_lock))
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return -EBUSY;
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if (nowayout)
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@ -231,15 +250,14 @@ static int s3c2410wdt_release(struct inode *inode, struct file *file)
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* Lock it in if it's a module and we set nowayout
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*/
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if (allow_close == CLOSE_STATE_ALLOW) {
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if (allow_close == CLOSE_STATE_ALLOW)
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s3c2410wdt_stop();
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} else {
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else {
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dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n");
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s3c2410wdt_keepalive();
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}
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allow_close = CLOSE_STATE_NOT;
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up(&open_lock);
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clear_bit(0, &open_lock);
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return 0;
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}
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@ -249,7 +267,7 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
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/*
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* Refresh the timer.
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*/
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if(len) {
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if (len) {
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if (!nowayout) {
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size_t i;
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@ -265,7 +283,6 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
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allow_close = CLOSE_STATE_ALLOW;
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}
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}
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s3c2410wdt_keepalive();
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}
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return len;
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@ -273,48 +290,41 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
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#define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE
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static struct watchdog_info s3c2410_wdt_ident = {
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static const struct watchdog_info s3c2410_wdt_ident = {
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.options = OPTIONS,
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.firmware_version = 0,
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.identity = "S3C2410 Watchdog",
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};
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static int s3c2410wdt_ioctl(struct inode *inode, struct file *file,
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unsigned int cmd, unsigned long arg)
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static long s3c2410wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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int new_margin;
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switch (cmd) {
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default:
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return -ENOTTY;
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case WDIOC_GETSUPPORT:
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return copy_to_user(argp, &s3c2410_wdt_ident,
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sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, p);
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case WDIOC_KEEPALIVE:
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s3c2410wdt_keepalive();
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_margin, p))
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return -EFAULT;
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if (s3c2410wdt_set_heartbeat(new_margin))
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return -EINVAL;
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s3c2410wdt_keepalive();
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return put_user(tmr_margin, p);
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case WDIOC_GETTIMEOUT:
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return put_user(tmr_margin, p);
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default:
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return -ENOTTY;
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case WDIOC_GETSUPPORT:
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return copy_to_user(argp, &s3c2410_wdt_ident,
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sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, p);
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case WDIOC_KEEPALIVE:
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s3c2410wdt_keepalive();
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_margin, p))
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return -EFAULT;
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if (s3c2410wdt_set_heartbeat(new_margin))
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return -EINVAL;
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s3c2410wdt_keepalive();
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return put_user(tmr_margin, p);
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case WDIOC_GETTIMEOUT:
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return put_user(tmr_margin, p);
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}
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}
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@ -324,7 +334,7 @@ static const struct file_operations s3c2410wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = s3c2410wdt_write,
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.ioctl = s3c2410wdt_ioctl,
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.unlocked_ioctl = s3c2410wdt_ioctl,
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.open = s3c2410wdt_open,
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.release = s3c2410wdt_release,
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};
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@ -411,14 +421,15 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
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* not, try the default value */
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if (s3c2410wdt_set_heartbeat(tmr_margin)) {
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started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
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started = s3c2410wdt_set_heartbeat(
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CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
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if (started == 0) {
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dev_info(dev,"tmr_margin value out of range, default %d used\n",
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if (started == 0)
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dev_info(dev,
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"tmr_margin value out of range, default %d used\n",
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CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
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} else {
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else
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dev_info(dev, "default timer value is out of range, cannot start\n");
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}
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}
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ret = misc_register(&s3c2410wdt_miscdev);
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@ -447,7 +458,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
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(wtcon & S3C2410_WTCON_ENABLE) ? "" : "in",
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(wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
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(wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
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return 0;
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err_clk:
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@ -487,7 +498,7 @@ static int s3c2410wdt_remove(struct platform_device *dev)
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static void s3c2410wdt_shutdown(struct platform_device *dev)
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{
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s3c2410wdt_stop();
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s3c2410wdt_stop();
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}
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#ifdef CONFIG_PM
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@ -540,7 +551,8 @@ static struct platform_driver s3c2410wdt_driver = {
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};
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static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
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static char banner[] __initdata =
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KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
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static int __init watchdog_init(void)
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{
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