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>

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

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));
+}

board/sandbox/sandbox.c

@@ -28,10 +28,6 @@ U_BOOT_DEVICE(gpio_sandbox) = {
 };
 #endif
 
-void flush_cache(unsigned long start, unsigned long size)
-{
-}
-
 #ifndef CONFIG_TIMER
 /* system timer offset in ms */
 static unsigned long sandbox_timer_offset;