[WATCHDOG] pnx4008_wdt.c - spinlock fixes.
Add io spinlocks to prevent possible race
conditions between start and stop operations
that are issued from different child processes
where the master process opened /dev/watchdog.
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/char/watchdog/pnx4008_wdt.c b/drivers/char/watchdog/pnx4008_wdt.c
index 465dfd3..359168e 100644
--- a/drivers/char/watchdog/pnx4008_wdt.c
+++ b/drivers/char/watchdog/pnx4008_wdt.c
@@ -28,6 +28,7 @@
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
+#include <linux/spinlock.h>
#include <asm/hardware.h>
#include <asm/uaccess.h>
@@ -80,6 +81,7 @@
static int nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat = DEFAULT_HEARTBEAT;
+static spinlock_t io_lock;
static unsigned long wdt_status;
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
@@ -94,6 +96,8 @@
static void wdt_enable(void)
{
+ spin_lock(&io_lock);
+
if (wdt_clk)
clk_set_rate(wdt_clk, 1);
@@ -113,13 +117,19 @@
__raw_writel(heartbeat * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
/*enable counter, stop when debugger active */
__raw_writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
+
+ spin_unlock(&io_lock);
}
static void wdt_disable(void)
{
+ spin_lock(&io_lock);
+
__raw_writel(0, WDTIM_CTRL(wdt_base)); /*stop counter */
if (wdt_clk)
clk_set_rate(wdt_clk, 0);
+
+ spin_unlock(&io_lock);
}
static int pnx4008_wdt_open(struct inode *inode, struct file *file)
@@ -248,6 +258,8 @@
int ret = 0, size;
struct resource *res;
+ spin_lock_init(&io_lock);
+
if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
heartbeat = DEFAULT_HEARTBEAT;