diff --git a/plat/arm/css/drivers/mhu/css_mhu_doorbell.c b/plat/arm/css/drivers/mhu/css_mhu_doorbell.c
new file mode 100644
index 0000000..b9faf67
--- /dev/null
+++ b/plat/arm/css/drivers/mhu/css_mhu_doorbell.c
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2014-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch_helpers.h>
+#include <platform_def.h>
+#include "css_mhu_doorbell.h"
+#include "../scmi/scmi.h"
+
+void mhu_ring_doorbell(scmi_channel_plat_info_t *plat_info)
+{
+	MHU_RING_DOORBELL(plat_info->db_reg_addr,
+			plat_info->db_modify_mask,
+			plat_info->db_preserve_mask);
+	return;
+}
+
+void mhuv2_ring_doorbell(scmi_channel_plat_info_t *plat_info)
+{
+	/* wake receiver */
+	MHU_V2_ACCESS_REQUEST(MHUV2_BASE_ADDR);
+
+	/* wait for receiver to acknowledge its ready */
+	while (MHU_V2_IS_ACCESS_READY(MHUV2_BASE_ADDR) == 0)
+		;
+
+	MHU_RING_DOORBELL(plat_info->db_reg_addr,
+			plat_info->db_modify_mask,
+			plat_info->db_preserve_mask);
+
+	/* clear the access request for the recevier */
+	MHU_V2_CLEAR_REQUEST(MHUV2_BASE_ADDR);
+
+	return;
+}