fix(sptool): add dependency to SP image

In the generated sp_gen.mk, add a dependency to the image described in
the sp_layout.json file to make sure that the pkg file is re-generated
if the SP image is updated.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Change-Id: Id936f907d6baa6b0627c4bb9608323e5157c7a9b

tools/sptool/sp_mk_generator.py

@@ -132,20 +132,21 @@ def gen_sptool_args(sp_layout, sp, args :dict):
     sp_pkg = get_sp_pkg(sp, args)
     sp_dtb_name = os.path.basename(get_file_from_layout(sp_layout[sp]["pm"]))[:-1] + "b"
     sp_dtb = os.path.join(args["out_dir"], f"fdts/{sp_dtb_name}")
+    sp_img = get_sp_img_full_path(sp_layout[sp], args)
 
     # Do not generate rule if already there.
     if is_line_in_sp_gen(f'{sp_pkg}:', args):
         return args
     write_to_sp_mk_gen(f"SP_PKGS += {sp_pkg}\n", args)
 
-    sptool_args = f" -i {get_sp_img_full_path(sp_layout[sp], args)}:{sp_dtb}"
+    sptool_args = f" -i {sp_img}:{sp_dtb}"
     pm_offset = get_pm_offset(sp_layout[sp])
     sptool_args += f" --pm-offset {pm_offset}" if pm_offset is not None else ""
     image_offset = get_image_offset(sp_layout[sp])
     sptool_args += f" --img-offset {image_offset}" if image_offset is not None else ""
     sptool_args += f" -o {sp_pkg}"
     sppkg_rule = f'''
-{sp_pkg}: {sp_dtb}
+{sp_pkg}: {sp_dtb} {sp_img}
 \t$(Q)echo Generating {sp_pkg}
 \t$(Q)$(PYTHON) $(SPTOOL) {sptool_args}
 '''