avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/arch/sandbox/include/asm/global_data.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ *
+ * (C) Copyright 2002-2010
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef	__ASM_GBL_DATA_H
+#define __ASM_GBL_DATA_H
+
+/* Architecture-specific global data */
+struct arch_global_data {
+	uint8_t		*ram_buf;	/* emulated RAM buffer */
+};
+
+#include <asm-generic/global_data.h>
+
+#define DECLARE_GLOBAL_DATA_PTR     extern gd_t *gd
+
+#endif /* __ASM_GBL_DATA_H */