[WATCHDOG] rc32434_wdt: add spin_locking

Add spin_locks to prevent races.

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/watchdog/rc32434_wdt.c b/drivers/watchdog/rc32434_wdt.c
index eee29923a14d..bffd4a2b1151 100644
--- a/drivers/watchdog/rc32434_wdt.c
+++ b/drivers/watchdog/rc32434_wdt.c
@@ -28,6 +28,7 @@
 #include <linux/watchdog.h>             /* For the watchdog specific items */
 #include <linux/init.h>                 /* For __init/__exit/... */
 #include <linux/platform_device.h>      /* For platform_driver framework */
+#include <linux/spinlock.h>             /* For spin_lock/spin_unlock/... */
 #include <linux/uaccess.h>              /* For copy_to_user/put_user/... */
 
 #include <asm/mach-rc32434/integ.h>     /* For the Watchdog registers */
@@ -38,6 +39,7 @@
 
 static struct {
         unsigned long inuse;
+        spinlock_t io_lock;
 } rc32434_wdt_device;
 
 static struct integ __iomem *wdt_reg;
@@ -81,7 +83,9 @@ static int rc32434_wdt_set(int new_timeout)
                 return -EINVAL;
         }
         timeout = new_timeout;
+        spin_lock(&rc32434_wdt_device.io_lock);
         writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare);
+        spin_unlock(&rc32434_wdt_device.io_lock);
 
         return 0;
 }
@@ -90,6 +94,8 @@ static void rc32434_wdt_start(void)
 {
         u32 or, nand;
 
+        spin_lock(&rc32434_wdt_device.io_lock);
+
         /* zero the counter before enabling */
         writel(0, &wdt_reg->wtcount);
 
@@ -112,20 +118,26 @@ static void rc32434_wdt_start(void)
 
         SET_BITS(wdt_reg->wtc, or, nand);
 
+        spin_unlock(&rc32434_wdt_device.io_lock);
         printk(KERN_INFO PFX "Started watchdog timer.\n");
 }
 
 static void rc32434_wdt_stop(void)
 {
+        spin_lock(&rc32434_wdt_device.io_lock);
+
         /* Disable WDT */
         SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN);
 
+        spin_unlock(&rc32434_wdt_device.io_lock);
         printk(KERN_INFO PFX "Stopped watchdog timer.\n");
 }
 
 static void rc32434_wdt_ping(void)
 {
+        spin_lock(&rc32434_wdt_device.io_lock);
         writel(0, &wdt_reg->wtcount);
+        spin_unlock(&rc32434_wdt_device.io_lock);
 }
 
 static int rc32434_wdt_open(struct inode *inode, struct file *file)
@@ -270,6 +282,8 @@ static int __devinit rc32434_wdt_probe(struct platform_device *pdev)
                 return -ENXIO;
         }
 
+        spin_lock_init(&rc32434_wdt_device.io_lock);
+
         /* Check that the heartbeat value is within it's range;
          * if not reset to the default */
         if (rc32434_wdt_set(timeout)) {