coreboot: rk3288: Add a stub implementation of the rk3288 SOC

Most things still needs to be filled in, but this will allow us to build boards which use this SOC.

BUG=chrome-os-partner:29778
TEST=emerge-veyron coreboot

Original-Change-Id: If643d620c5fb8951faaf1ccde400a8e9ed7db3bc
Original-Signed-off-by: jinkun.hong <jinkun.hong@rock-chips.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/205069
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Original-Commit-Queue: David Hendricks <dhendrix@chromium.org>
Original-Tested-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit 2f72473a8c2b3fe21d77b351338e6209035878fb)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I53fd0ced42f6ef191d7bf80d8b823bb880344239
Reviewed-on: http://review.coreboot.org/8653
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/src/soc/rockchip/rk3288/cbmem.c b/src/soc/rockchip/rk3288/cbmem.c
new file mode 100644
index 0000000..b29c87a
--- /dev/null
+++ b/src/soc/rockchip/rk3288/cbmem.c
@@ -0,0 +1,29 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2014 Rockchip 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 <stddef.h>
+#include <cbmem.h>
+
+#define FB_SIZE_MB	4
+void *cbmem_top(void)
+{
+	return (void *)(CONFIG_SYS_SDRAM_BASE +
+			(CONFIG_DRAM_SIZE_MB - FB_SIZE_MB)*MiB);
+}
+