sandbox: implement invalidate_icache_all()

Before executing code that we have loaded from a file we need to flush the
data cache and invalidate the instruction flash.

Implement functions flush_cache() and invalidate_icache_all().

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/cpu/Makefile b/arch/sandbox/cpu/Makefile
index bac9644..de7fe7f 100644
--- a/arch/sandbox/cpu/Makefile
+++ b/arch/sandbox/cpu/Makefile
@@ -5,7 +5,7 @@
 # (C) Copyright 2000-2003
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 
-obj-y	:= cpu.o state.o
+obj-y	:= cache.o cpu.o state.o
 extra-y	:= start.o os.o
 extra-$(CONFIG_SANDBOX_SDL)	+= sdl.o
 obj-$(CONFIG_SPL_BUILD)	+= spl.o
diff --git a/arch/sandbox/cpu/cache.c b/arch/sandbox/cpu/cache.c
new file mode 100644
index 0000000..46c62c0
--- /dev/null
+++ b/arch/sandbox/cpu/cache.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
+ */
+
+#include <common.h>
+#include <cpu_func.h>
+#include <asm/state.h>
+
+void flush_cache(unsigned long addr, unsigned long size)
+{
+	/* Clang uses (char *) parameters, GCC (void *) */
+	__builtin___clear_cache((void *)addr, (void *)(addr + size));
+}
+
+void invalidate_icache_all(void)
+{
+	struct sandbox_state *state = state_get_current();
+
+	/* Clang uses (char *) parameters, GCC (void *) */
+	__builtin___clear_cache((void *)state->ram_buf,
+				(void *)(state->ram_buf + state->ram_size));
+}