sandbox: fdt: Support fdt command for sandbox

By using map_sysmem() we can get the fdt command to work correctly with
sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/cmd_fdt.c

@@ -31,6 +31,7 @@
 #include <asm/global_data.h>
 #include <libfdt.h>
 #include <fdt_support.h>
+#include <asm/io.h>
 
 #define MAX_LEVEL	32		/* how deeply nested we will go */
 #define SCRATCHPAD	1024		/* bytes of scratchpad memory */
@@ -55,7 +56,10 @@ struct fdt_header *working_fdt;
 
 void set_working_fdt_addr(void *addr)
 {
-	working_fdt = addr;
+	void *buf;
+
+	buf = map_sysmem((ulong)addr, 0);
+	working_fdt = buf;
 	setenv_addr("fdtaddr", addr);
 }
 
@@ -129,13 +133,13 @@ static int do_fdt(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 		}
 
 		addr = simple_strtoul(argv[0], NULL, 16);
-		blob = (struct fdt_header *)addr;
+		blob = map_sysmem(addr, 0);
 		if (!fdt_valid(&blob))
 			return 1;
 		if (control)
 			gd->fdt_blob = blob;
 		else
-			set_working_fdt_addr((void *)addr);
+			set_working_fdt_addr(blob);
 
 		if (argc >= 2) {
 			int  len;