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/arm/lib/cmd_boot.c

@@ -0,0 +1,44 @@
+/*
+ * (C) Copyright 2008-2011
+ * Graeme Russ, <graeme.russ@gmail.com>
+ *
+ * (C) Copyright 2002
+ * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
+ *
+ * (C) Copyright 2002
+ * Wolfgang Denk, DENX Software Engineering, <wd@denx.de>
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Marius Groeger <mgroeger@sysgo.de>
+ *
+ * Copyright 2015 ATS Advanced Telematics Systems GmbH
+ * Copyright 2015 Konsulko Group, Matt Porter <mporter@konsulko.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <command.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * ARMv7M does not support ARM instruction mode. However, the
+ * interworking BLX and BX instructions do encode the ARM/Thumb
+ * field in bit 0. This means that when executing any Branch
+ * and eXchange instruction we must set bit 0 to one to guarantee
+ * that we keep the processor in Thumb instruction mode. From The
+ * ARMv7-M Instruction Set A4.1.1:
+ *   "ARMv7-M only supports the Thumb instruction execution state,
+ *    therefore the value of address bit [0] must be 1 in interworking
+ *    instructions, otherwise a fault occurs."
+ */
+unsigned long do_go_exec(ulong (*entry)(int, char * const []),
+			 int argc, char * const argv[])
+{
+	ulong addr = (ulong)entry | 1;
+	entry = (void *)addr;
+
+	return entry(argc, argv);
+}