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/powerpc/lib/cache.c

@@ -0,0 +1,37 @@
+/*
+ * (C) Copyright 2002
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/cache.h>
+#include <watchdog.h>
+
+void flush_cache(ulong start_addr, ulong size)
+{
+#ifndef CONFIG_5xx
+	ulong addr, start, end;
+
+	start = start_addr & ~(CONFIG_SYS_CACHELINE_SIZE - 1);
+	end = start_addr + size - 1;
+
+	for (addr = start; (addr <= end) && (addr >= start);
+			addr += CONFIG_SYS_CACHELINE_SIZE) {
+		asm volatile("dcbst 0,%0" : : "r" (addr) : "memory");
+		WATCHDOG_RESET();
+	}
+	/* wait for all dcbst to complete on bus */
+	asm volatile("sync" : : : "memory");
+
+	for (addr = start; (addr <= end) && (addr >= start);
+			addr += CONFIG_SYS_CACHELINE_SIZE) {
+		asm volatile("icbi 0,%0" : : "r" (addr) : "memory");
+		WATCHDOG_RESET();
+	}
+	asm volatile("sync" : : : "memory");
+	/* flush prefetch queue */
+	asm volatile("isync" : : : "memory");
+#endif
+}