bg4cd: add uart driver skeleton

This adds the file to be filled up with the uart driver implementation
for bg4cd.

The console driver structure when required is provided by
src/console/uart_wrapper.c.

BRANCH=none
BUG=chrome-os-partner:32772
TEST=none yet, this file is not event being compiled

Change-Id: I73c12ddcd6f5099cc2196820452e714eeb736cdc
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/223595
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/marvell/bg4cd/uart.c

@@ -0,0 +1,47 @@
+/*
+ * This file is part of the coreboot project.
+ * Copyright 2014 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <uart.h>
+
+void uart_init(void)
+{
+}
+
+void uart_tx_byte(unsigned char data)
+{
+}
+
+int uart_can_rx_byte(void)
+{
+	return 0;
+}
+
+void uart_tx_flush(void)
+{
+}
+
+unsigned char uart_rx_byte(void)
+{
+	return '\0';
+}
+
+/* Not really needed on this chip, but helps to keep coreboot table happy. */
+u32 uartmem_getbaseaddr(void)
+{
+	return 0;
+}