sh: Use internal watchdog timer to perform reset

This patches will trigger a reboot using the watchdog
timer instead of double fault.  Unlike the previous
method, this one actually works in 32 bit mode.

Reset should also be cleaner.
Signed-off-by: Jon Frosdick <jon.frosdick@st.com>
Signed-off-by: Carl Shaw <carl.shaw@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/process_32.c

@@ -32,15 +32,35 @@
 #include <asm/ubc.h>
 #include <asm/fpu.h>
 #include <asm/syscalls.h>
+#include <asm/watchdog.h>
 
 int ubc_usercnt = 0;
 
+#ifdef CONFIG_32BIT
+static void watchdog_trigger_immediate(void)
+{
+	sh_wdt_write_cnt(0xFF);
+	sh_wdt_write_csr(0xC2);
+}
+
+void machine_restart(char * __unused)
+{
+	local_irq_disable();
+
+	/* Use watchdog timer to trigger reset */
+	watchdog_trigger_immediate();
+
+	while (1)
+		cpu_sleep();
+}
+#else
 void machine_restart(char * __unused)
 {
 	/* SR.BL=1 and invoke address error to let CPU reset (manual reset) */
 	asm volatile("ldc %0, sr\n\t"
 		     "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001));
 }
+#endif
 
 void machine_halt(void)
 {