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/cpu/arm926ejs/cpu.c

@@ -0,0 +1,53 @@
+/*
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Marius Groeger <mgroeger@sysgo.de>
+ *
+ * (C) Copyright 2002
+ * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/*
+ * CPU specific code
+ */
+
+#include <common.h>
+#include <command.h>
+#include <asm/system.h>
+
+static void cache_flush(void);
+
+int cleanup_before_linux (void)
+{
+	/*
+	 * this function is called just before we call linux
+	 * it prepares the processor for linux
+	 *
+	 * we turn off caches etc ...
+	 */
+
+	disable_interrupts ();
+
+
+	/* turn off I/D-cache */
+	icache_disable();
+	dcache_disable();
+	l2_cache_disable();
+
+	/* flush I/D-cache */
+	cache_flush();
+
+	return 0;
+}
+
+/* flush I/D-cache */
+static void cache_flush (void)
+{
+#if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
+	unsigned long i = 0;
+
+	asm ("mcr p15, 0, %0, c7, c7, 0": :"r" (i));
+#endif
+}