• Masahiro Yamada's avatar
    ARM: 8969/1: decompressor: simplify libfdt builds · 7ae4a78d
    Masahiro Yamada authored
    
    
    Copying source files during the build time may not end up with
    as clean code as expected.
    
    lib/fdt*.c simply wrap scripts/dtc/libfdt/fdt*.c, and it works
    nicely. Let's follow this approach for the arm decompressor, too.
    
    Add four wrappers, arch/arm/boot/compressed/fdt*.c and remove
    the Makefile messes. Another nice thing is we no longer need to
    maintain the own libfdt_env.h because the decompressor can include
    <linux/libfdt_env.h>.
    
    There is a subtle problem when generated files are turned into
    check-in files.
    
    When you are doing a rebuild of an existing object tree with O=
    option, there exists stale "shipped" copies that the old Makefile
    implementation created. The build system ends up with compiling the
    stale generated files because Make searches for prerequisites in the
    current directory, i.e. $(objtree) first, and then the directory
    listed in VPATH, i.e. $(srctree).
    
    To mend this issue, I added the following code:
    
      ifdef building_out_of_srctree
      $(shell rm -f $(addprefix $(obj)/, fdt_rw.c fdt_ro.c fdt_wip.c fdt.c))
      endif
    
    This will need to stay for a while because "git bisect" crossing this
    commit, otherwise, would result in a build error.
    Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
    Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
    7ae4a78d
Makefile 5.52 KB