kbuild: avoid race between dtbs and dt/dt.dtb targets

If the final targets depend on both "dtbs" and "dts/dt.dtb",
and -j option is given to the command line, multiple threads
descend into the dts/ directory, which causes build error.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Andreas Dannenberg <dannenberg@ti.com>

diff --git a/Makefile b/Makefile
index 256d4ff38fe574dc45f3c91dd69fa19ace1ffe8c..0c47bb66c19996e2fe6af72336af5c1ad5e5985e 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -810,7 +810,9 @@ ifeq ($(CONFIG_DM_I2C_COMPAT),y)
 endif
 
 PHONY += dtbs
-dtbs dts/dt.dtb: checkdtc u-boot
+dtbs: dts/dt.dtb
+       @:
+dts/dt.dtb: checkdtc u-boot
        $(Q)$(MAKE) $(build)=dts dtbs
 
 quiet_cmd_copy = COPY    $@