ARM: shmobile: kzm9g-reference: Add restart callback

Port the sh73a0 restart handling from the kzm9g-legacy board code to the
kzm9g-reference board code.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/board-kzm9g-reference.c

@@ -43,6 +43,13 @@ static void __init kzm_init(void)
 #endif
 }
 
+#define RESCNT2 IOMEM(0xe6188020)
+static void kzm9g_restart(enum reboot_mode mode, const char *cmd)
+{
+	/* Do soft power on reset */
+	writel((1 << 31), RESCNT2);
+}
+
 static const char *kzm9g_boards_compat_dt[] __initdata = {
 	"renesas,kzm9g-reference",
 	NULL,
@@ -54,5 +61,6 @@ DT_MACHINE_START(KZM9G_DT, "kzm9g-reference")
 	.init_early	= shmobile_init_delay,
 	.init_machine	= kzm_init,
 	.init_late	= shmobile_init_late,
+	.restart	= kzm9g_restart,
 	.dt_compat	= kzm9g_boards_compat_dt,
 MACHINE_END