scripts: Add some comments about autoconf.mk

Now that the conversion of all CONFIG options to Kconfig is complete,
these files only contain the xPL_BUILD defines. Add a comment to make
this clear.

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

diff --git a/scripts/Makefile.xpl b/scripts/Makefile.xpl
index 1868f1beef66986e5a03318ce6020d44ef1b46a3..3091311a3d279d3b1880e964850c15e34e7817ba 100644 (file)
--- a/scripts/Makefile.xpl
+++ b/scripts/Makefile.xpl
@@ -20,6 +20,12 @@ _dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
 include $(srctree)/scripts/Kbuild.include
 
 -include include/config/auto.conf
+
+# This file contains 0, 1 or 2 lines
+# It is empty for U-Boot proper (where $(obj) is empty)
+# For any xPL build it contains CONFIG_SPL_BUILD=y
+# For TPL builds it has CONFIG_SPL_BUILD=y and CONFIG_TPL_BUILD=y
+# For VPL builds it has CONFIG_SPL_BUILD=y and CONFIG_VPL_BUILD=y
 -include $(obj)/include/autoconf.mk
 
 UBOOTINCLUDE := -I$(obj)/include $(UBOOTINCLUDE)