kbuild,tools: generate wrapper C sources automatically by Makefile

There are many source files shared between U-boot image and tools.
Instead of adding a lot of dummy wrapper files that just include
the corresponding file in lib/ or common/ directory,
Makefile should automatically generate them.

The original inspiration for this came from
scripts/Makefile.asm-generic of Linux Kernel.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Series-to: uboot
Series-cc: sjg
Series-cc: Charles Manning <cdhmanning@gmail.com>
Series-cc: Gerhard Sittig <gsi@denx.de>
Series-version: 2
Series-changes: 2
  - Rebase on commit 3e1fa221
kbuild: export HOSTCXX and HOSTCXXFLAGS

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kconfig: import Kconfig files from Linux v3.15-rc7

Import
  - scripts/kconfig/*
  - include/linux/kconfig.h
from Linux Kernel v3.15-rc7.

I know they include lots of trailing spaces
but I keep intentionally them untouched.

Series-to: u-boot@lists.denx.de
Series-cc: Simon Glass <sjg@chromium.org>
Series-cc: Tom Rini <trini@ti.com>
Series-cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Series-cc: Wolfgang Denk <wd@denx.de>
Series-version: 3
Series-changes: 3
 - Fetch source files from the latest Linux tag
Series-changes: 2
 - Fetch source files from the latest Linux tag

Cover-letter:
Kconfig for U-Boot
This series introduces Kconfig.

Besides Linux Kernel, Kconfig is used in some projects,
such as, BusyBox, Buildroot.

But our situation is a little more complicated.
For one board, we need to generate 3 images at most:
Full image, SPL and TPL.

Each image needs its own configuration input.

 How does Kconfig in U-Boot work?
 --------------------------------

For boards without SPL support, it works as in Linux Kernel.
"make <board>_defconfig" creates .config for you.
You can use "make config", "make menuconfig" etc. to create a new .config
from scratch or update the existing one.

"make silentoldconfig", if it is necessary, is automatically invoked,
creating or updating include/config/auto.conf and
include/generated/autoconf.h.

For boards with SPL/TPL support, another .config file is created
under spl/tpl directory.

To sum up, the location of Kconfig related files is as follows:

  [1] Full U-boot
    - configs/<board>_defconfig        (default configuration)
    - .config                          (saved config list)
    - include/config/auto.conf         (for use in makefiles)
    - include/generated/autoconf.h     (for use in C sources)
    - include/config/*                 (for if_changed_dep)

  [2] SPL
    - configs/spl/<board>_defconfig    (default configuration)
    - spl/.config                      (saved config list)
    - spl/include/config/auto.conf     (for use in makefiles)
    - spl/include/generated/autoconf.h (for use in C sources)
    - spl/include/config/*             (for if_changed_dep)

  [3] TPL
    - configs/tpl/<board>_defconfig    (default configuration)
    - tpl/.config                      (saved config list)
    - tpl/include/config/auto.conf     (for use in makefiles)
    - tpl/include/generated/autoconf.h (for use in C sources)
    - tpl/include/config/*             (for if_changed_dep)

 How to configure and build?
 ---------------------------

For board configuration, "make <board>_defconfig" is used instead of
"make <board>_config". The other things are the same as before.

 Coexistence of Kconfig and board header
 ---------------------------------------

For a long time, we have used C header files to define the set of CONFIGs.

It would take really long term (one year? two year? I don't know)
to migrate from board headers to Kconfig.

So, two different infractructure must coexist in the interim.

CONFIG macros defined in C headers are collected into
include/autoconf.mk, spl/include/autoconf.mk, tpl/include/autoconf.mk
for use in makefiles.

 Build Test
 ----------

I built all boards excepts some already broken ones.
I also checked MD5SUM of output binaries for all of them.

I believe this series should not break any boards.
But if you notice something got broken, please let me know.

Besides, I confirmed out-of-tree build, parallel build (-j make option)
works correctly.

 How to apply this series
 ------------------------

I confirmed this series can be applied on commit f23adc9f.

 Known Problems
 --------------

[1] MAKEALL and buildman have not been not adjusted yet

boards.cfg is not necessary for Kconfig. I want to delete it.

But before that, we must rework MAKEALL and buildman to search defconfig
files instead of boards.cfg.

[2] Many targets in one choice

Especially in ARM and PowerPC, there are too many target boards
in one choice.

This should be refactored in follow-up patches
by increasing the hierarchy and grouping the similar boards family.

END
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Do not apply: tools: add genkconfig

 ========================================
 Do not apply this patch to the main line
 ========================================

 What is this tool?
 ------------------

This tool converts boards.cfg to defconfig and Kconfig files.

It automatically generates
 - arch/${ARCH}/Kconfig
 - board/${VENDOR}/${BOARD}/Kconfig
 - board/${BOARD}/Kconfig
 - configs/${TARGET_BOARD}_defconfig

 How to use?
 -----------

Open tools/print_allconfigs with an editor.

Adjust cross compilers part for your environment.

  # Specify your favoriate cross tools
  CROSS_COMPILE_ARC=arc-linux-
  CROSS_COMPILE_AARCH64=aarch64-linux-gnu-
  CROSS_COMPILE_ARM=arm-unknown-linux-gnueabi-
   [snip]
  CROSS_COMPILE_X86=i386-linux-

And then, run "tools/genkconfig".

 Why is this patch here?
 -----------------------

The file boards.cfg is touched very frequently.
All the time, new/old boards are being added/removed.

The next commit was generated based on the u-boot/master at the time
I posted it.
It will become out-dated soon.

You can update it with this tool.

Series-changes: 2
 - Do not output CONFIG_BOARD_MAINTAINERS and CONFIG_BOARD_STATUS
 - Delete board/Kconfig and move "source board/*/*/Kconfig"
   statements to arch/*/Kconfig.
kconfig: add board Kconfig and defconfig files

This commit adds:
 - arch/${ARCH}/Kconfig
    provide a menu to select target boards
 - board/${VENDOR}/${BOARD}/Kconfig or board/${BOARD}/Kconfig
    set CONFIG macros to the appropriate values for each board
 - configs/${TARGET_BOARD}_defconfig
    default setting of each board

(This commit was automatically generated by a conversion script
based on boards.cfg)

In Linux Kernel, defconfig files are located under
arch/${ARCH}/configs/ directory.
It works in Linux Kernel since ARCH is always given from the
command line for cross compile.

But in U-Boot, ARCH is not given from the command line.
Which means we cannot know ARCH until the board configuration is done.
That is why all the "*_defconfig" files should be gathered into a
single directory ./configs/.
(The problem is configs/ directory contains about 1200 files!)

Besides, we must have separate defconfig for SPL and TPL too,
if they are supported.
SPL, TPL has its defconfig files under configs/spl/, configs/tpl/,
respectively.

Series-changes: 2
  - Re-generate based on the latest boards.cfg
kconfig: add basic Kconfig files

This commit adds more Kconfig files, which were written by hand.

Series-changes: 2
  - Do not include "board/Kconfig"
  - Drop CONFIG_BUILD_MODE
include: define CONFIG_SPL and CONFIG_TPL as 1

We are about to switch to Kconfig in the next commit.
But there are something to get done beforehand.

In Kconfig, include/generated/autoconf.h defines boolean
CONFIG macros as 1.

CONFIG_SPL and CONFIG_TPL, if defined, must be set to 1.
Otherwise, when switching to Kconfig, the build log
would be sprinkled with warning messages like this:
  warning: "CONFIG_SPL" redefined [enabled by default]

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Series-changes: 2
  - Rebase on the current u-boot/master
kconfig: switch to Kconfig

This commit enables Kconfig.
Going forward, we use Kconfig for 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 binary images (Full U-Boot, SPL, TPL)
from one source tree.
Each image needs its own configuration input.

In order to keep this scheme in Kconfig, some files must be modified.
But the modification should be minimum.

The location of Kconfig related files is as follows:

 [1] Full U-Boot image
   - configs/<board>_defconfig        (default configuration)
   - .config                          (saved config list)
   - include/config/auto.conf         (for use in makefiles)
   - include/generated/autoconf.h     (for use in C sources)
   - include/config/*                 (for if_changed_dep)

 [2] SPL
   - configs/spl/<board>_defconfig    (default configuration)
   - spl/.config                      (saved config list)
   - spl/include/config/auto.conf     (for use in makefiles)
   - spl/include/generated/autoconf.h (for use in C sources)
   - spl/include/config/*             (for if_changed_dep)

 [3] TPL
   - configs/tpl/<board>_defconfig    (default configuration)
   - tpl/.config                      (saved config list)
   - tpl/include/config/auto.conf     (for use in makefiles)
   - tpl/include/generated/autoconf.h (for use in C sources)
   - tpl/include/config/*             (for if_changed_dep)

Usage:

Execute "make <board>_defconfig" to configure board and then run "make".
Or "make <board>_defconfig all" to configure and build in one time.

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

In Kconfig for U-boot, the configuration is done on three levels at most.

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 full, SPL, TPL image, respectively.

Series-changes: 2
  - Put dirty build rule into scripts/multiple_config.sh and
    scripts/Makefile.autoconf
  - Fix dependency tracking.
    In v1, any change to Kconfig triggered re-complile of all objects.
    In this version, re-compile is kept at a minimum.
  - Fix a clean-source check
    In v1, clean source tree check did not work correctly for
    out-of-tree build.
Don't send: do not clean scripts/kconfig/* by make mrproper
MAKEALL: adjust for Kconfig

Use "make <board>_defconfig" instead of "make <board>_config".

FIXME!
This fixup is bad because it still depends on boards.cfg
to support options such as -a <ARCH>, -c <CPU> etc.
We want to delete it when switching to Kconfig.

We have to invent another method without using boards.cfg.
buildman: adjust for Kconfig

Use "make <board>_defconfig" instead of "make <board>_config".

FIXME!
This fixup is bad because it still depends on boards.cfg
to support options such as -a <ARCH>, -c <CPU> etc.
We want to delete it when switching to Kconfig.

We have to invent another method without using boards.cfg.
MAKEALL: Show configuration
kconfig: delete redundant CONFIG_${ARCH} definition

CONFIG_${ARCH} is defined by Kconfig.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
kbuild: remove CONFIG_SPL/CONFIG_TPL definition in config headers

Now CONFIG_SPL and CONFIG_TPL are defined in Kconfig.

Remove the redundant definition in config headers.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Series-changes: 2
  - Rebase on the current u-boot/master
kconfig: remove old script

mkconfig is no longer used in Kconfig.
kconfig: add CONFIG_CROSS_COMPILE

Copy from Linux Kernel (with a few adjustments in comments).
kconfig: Add CONFIG_CC_OPTIMIZE_FOR_SIZE
Do not apply: tools: add updatedefconfig