kconfig: switch to Kconfig

This commit enables Kconfig.
Going forward, we use Kconfig for the board configuration.
mkconfig will never be used. Nor will include/config.mk be generated.

Kconfig must be adjusted for U-Boot because our situation is
a little more complicated than Linux Kernel.
We have to generate multiple boot images (Normal, SPL, TPL)
from one source tree.
Each image needs its own configuration input.

Usage:

Run "make <board>_defconfig" to do the board configuration.

It will create the .config file and additionally spl/.config, tpl/.config
if SPL, TPL is enabled, respectively.

You can use "make config", "make menuconfig" etc. to create
a new .config or modify the existing one.

Use "make spl/config", "make spl/menuconfig" etc. for spl/.config
and do likewise for tpl/.config file.

The generic syntax of configuration targets for SPL, TPL is:

  <target_image>/<config_command>

Here, <target_image> is either 'spl' or 'tpl'
      <config_command> is 'config', 'menuconfig', 'xconfig', etc.

When the configuration is done, run "make".
(Or "make <board>_defconfig all" will do the configuration and build
in one time.)

For futher information of how Kconfig works in U-Boot,
please read the comment block of scripts/multiconfig.py.

By the way, there is another item worth remarking here:
coexistence of Kconfig and board herder files.

Prior to Kconfig, we used C headers to define a set of configs.

We expect a very long term to migrate from C headers to Kconfig.
Two different infractructure must coexist in the interim.

In our former configuration scheme, include/autoconf.mk was generated
for use in makefiles.
It is still generated under include/, spl/include/, tpl/include/ directory
for the Normal, SPL, TPL image, respectively.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/scripts/Makefile.spl b/scripts/Makefile.spl
index bf677aa..88c01d1 100644
--- a/scripts/Makefile.spl
+++ b/scripts/Makefile.spl
@@ -21,13 +21,10 @@
 
 include $(srctree)/scripts/Kbuild.include
 
-CONFIG_SPL_BUILD := y
-export CONFIG_SPL_BUILD
+UBOOTINCLUDE := -I$(obj)/include $(UBOOTINCLUDE)
 
-KBUILD_CPPFLAGS += -DCONFIG_SPL_BUILD
-ifeq ($(CONFIG_TPL_BUILD),y)
-KBUILD_CPPFLAGS += -DCONFIG_TPL_BUILD
-endif
+-include $(obj)/include/config/auto.conf
+-include $(obj)/include/autoconf.mk
 
 ifeq ($(CONFIG_TPL_BUILD),y)
 export CONFIG_TPL_BUILD
@@ -36,14 +33,6 @@
 SPL_BIN := u-boot-spl
 endif
 
-include include/config.mk
-
-ifeq ($(CONFIG_TPL_BUILD),y)
-  -include include/tpl-autoconf.mk
-else
-  -include include/spl-autoconf.mk
-endif
-
 include $(srctree)/config.mk
 
 # Enable garbage collection of un-used sections for SPL
@@ -53,20 +42,6 @@
 # FIX ME
 cpp_flags := $(KBUILD_CPPFLAGS) $(PLATFORM_CPPFLAGS) $(UBOOTINCLUDE) \
 							$(NOSTDINC_FLAGS)
-c_flags := $(KBUILD_CFLAGS) $(cpp_flags)
-
-# Auto-generate the spl-autoconf.mk file (which is included by all makefiles for SPL)
-quiet_cmd_autoconf = GEN     $@
-      cmd_autoconf = \
-	$(CPP) $(c_flags) -DDO_DEPS_ONLY -dM $(srctree)/include/common.h > $@.tmp && \
-		sed -n -f $(srctree)/tools/scripts/define2mk.sed $@.tmp > $@; \
-	rm $@.tmp
-
-include/tpl-autoconf.mk: include/config.h
-	$(call cmd,autoconf)
-
-include/spl-autoconf.mk: include/config.h
-	$(call cmd,autoconf)
 
 HAVE_VENDOR_COMMON_LIB = $(if $(wildcard $(srctree)/board/$(VENDOR)/common/Makefile),y,n)