ARM: SAMSUNG: fix watchdog reset issue with clk_get()

clkdev framework uses global mutex to protect clock tree, so it is not
possible to call clk_get() in interrupt context. This patch fixes this
issue and makes system reset by watchdog call working again.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/plat-samsung/clock.c

@@ -64,6 +64,17 @@ static LIST_HEAD(clocks);
  */
 DEFINE_SPINLOCK(clocks_lock);
 
+/* Global watchdog clock used by arch_wtd_reset() callback */
+struct clk *s3c2410_wdtclk;
+static int __init s3c_wdt_reset_init(void)
+{
+	s3c2410_wdtclk = clk_get(NULL, "watchdog");
+	if (IS_ERR(s3c2410_wdtclk))
+		printk(KERN_WARNING "%s: warning: cannot get watchdog clock\n", __func__);
+	return 0;
+}
+arch_initcall(s3c_wdt_reset_init);
+
 /* enable and disable calls for use with the clk struct */
 
 static int clk_null_enable(struct clk *clk, int enable)

arch/arm/plat-samsung/include/plat/clock.h

@@ -121,3 +121,6 @@ extern int s3c64xx_sclk_ctrl(struct clk *clk, int enable);
 
 extern void s3c_pwmclk_init(void);
 
+/* Global watchdog clock used by arch_wtd_reset() callback */
+
+extern struct clk *s3c2410_wdtclk;

arch/arm/plat-samsung/include/plat/watchdog-reset.h

@@ -10,6 +10,7 @@
  * published by the Free Software Foundation.
 */
 
+#include <plat/clock.h>
 #include <plat/regs-watchdog.h>
 #include <mach/map.h>
 
@@ -19,17 +20,12 @@
 
 static inline void arch_wdt_reset(void)
 {
-	struct clk *wdtclk;
-
 	printk("arch_reset: attempting watchdog reset\n");
 
 	__raw_writel(0, S3C2410_WTCON);	  /* disable watchdog, to be safe  */
 
-	wdtclk = clk_get(NULL, "watchdog");
-	if (!IS_ERR(wdtclk)) {
-		clk_enable(wdtclk);
-	} else
-		printk(KERN_WARNING "%s: warning: cannot get watchdog clock\n", __func__);
+	if (s3c2410_wdtclk)
+		clk_enable(s3c2410_wdtclk);
 
 	/* put initial values into count and data */
 	__raw_writel(0x80, S3C2410_WTCNT);