.gitignore: ingore files generated by Kbuild

Ignore generated files by Kbuild such as .*.cmd, *.order, etc.

Besides above,
 - Ignore *.s files
   We do not need to ignore with file name, asm-offsets.s
 - Do not ignore *.rej (for quilt)
 - Ignore backup files, \#*#

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile.host.tmp: add a new script to refactor tools

This commit adds scripts/Makefile.host.tmp which will
be used in the next commit to convert makefiles
under tools/ directory to Kbuild style.

Notice this script, scripts/Makefile.host.tmp
is temporary.

When switching over to real Kbuild,
it will be replaced with scripts/Makefile.host of Linux Kernel.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
tools: convert makefiles to kbuild style

Before this commit, makefiles under tools/ directory
were implemented with their own way.

This commit refactors them by using "hostprogs-y" variable.

Several C sources have been added to wrap other C sources
to simplify Makefile.
For example, tools/crc32.c includes lib/crc32.c

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
board: samsung: refactor host programs

Some Samsung boards have their own tools under board/samsung/<board>/tools/.
This commit refactor more makefiles with "hostprogs-y".

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
examples: Use scripts/Makefile.build

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
nand-spl: Use scripts/Makefile.build

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makfile: move suffix rules to Makefile.build

This commit moves suffix rules from config.mk
to scripts/Makefile.build, which will allow us
to switch smoothly to real Kbuild.

Note1:
post/lib_powerpc/fpu/Makefile has
its own rule to compile C sources.
We need to tweak it to keep the same behavior.

Note2:
There are two file2 with the same name:
arch/arm/lib/crt0.S and eamples/api/crt0.S.
To keep the same build behavior,
examples/api/Makefile also has to be treaked.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: move some variable definitions to the top Makefile

This commit moves some variable definitions from config.mk
to the top Makefile:

  - HOSTCC, HOSTCFLAGS, HOSTLDFLAGS
  - AS, LD, CC, CPP, etc.
  - SHELL (renamed to CONFIG_SHELL)

I'd like to slim down config.mk file
because it is included from all recursive make.
It is redundant to re-define the variables
every time descending into sub directories.
We should rather define them at the top Makefile
and export them.

U-Boot makefiles has been used "SHELL" variable to store shell
chosen for the user, whereas Linux Kernel uses "CONFIG_SHELL".

We should never use "SHELL" variable because it is
a special variable for GNU Make.
Changing SHELL may cause unpredictable side effects
whose root cause is usually difficult to find.
We should use a generic variable name "CONFIG_SHELL".

We should not use the syntax as follows either:

    rm -f $(obj)tools/env/{fw_printenv,fw_setenv}

This depends on "bash" although GNU Make generally
invokes "sh" to run the each rule.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: move BFD_ROOT_DIR to tools/gdb/Makefile

BFD_ROOT_DIR is used only in tools/gdb/Makefile

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: import Kbuild.include from linux v3.13 tag

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: Use Kbuild.include

This commit adjusts some files to use Kbuild.include.

 - Use cc-option defined in Kbuild.include
    (Delete cc-option in config.mk)
 - Use cc-version defined in
    (Delete cc-version in config.mk)
 - Move binutils-version and dtc-version to Kbuild.include
     by analogy to cc-version

This commit also adds srctree (same as SRCTREE)
to use Kbuild scripts.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: move more flags to the top Makefile

Before this commit, most of compiler flags were defined in config.mk.
But it is redundant because config.mk is included from all recursive make.

This commit moves many complier flags to the top Makefile
and export them.
And we use new vaiarables to store them:
KBUILD_CPPFLAGS, KBUILD_CFLAGS, KBUILD_AFLAGS.
This will allow us to switch more smoothly to Kbuild.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: refactor include path settings

This commit merges commonly-used header include paths
to UBOOTINCLUDE and NOSTDINC_FLAGS variables, which are placed
at the top Makefile.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: move more stuff to top Makefile

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: move some flags to spl/Makefile

Some flags are used for SPL (and TPL) build only.
This commit moves them from config.mk to spl/Makefile.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: move some flags to examples makefiles

This commit moves some flags which are used
under examples/ directory only.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: change out-of-tree build

This commit changes the working directory
where the build process occurs.

Before this commit, build process occurred under the source
tree for both in-tree and out-of-tree build.

That's why we needed to add $(obj) prefix to all generated
files in makefiles like follows:
  $(obj)u-boot.bin:  $(obj)u-boot

Here, $(obj) is empty for in-tree build, whereas it points
to the output directory for out-of-tree build.

And our old build system changes the current working directory
with "make -C <sub-dir>" syntax when descending into the
sub-directories.

On the other hand, Kbuild uses a different idea
to handle out-of-tree build and directory descending.

The build process of Kbuild always occurs under the output tree.
When "O=dir/to/store/output/files" is given, the build system
changes the current working directory to that directory and
restarts the make.

Kbuild uses "make -f $(srctree)/scripts/Makefile.build obj=<sub-dir>"
syntax for descending into sub-directories.
(We can write it like "make $(obj)=<sub-dir>" with a shorthand.)
This means the current working directory is always the top
of the output directory.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Gerhard Sittig <gsi@denx.de>
kbuild: add dummy obj-y to create built-in.o

We are going to switch over to Kbuild in upcoming commits.

Each makefile must have non-empty obj- or obj-y
to generate built-in.o on Kbuild.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: rename scripts/Makefile.build to scripts/Makefile.build.tmp

Some build scripts including scripts/Makefile.build
will be imported from Linux Kernel in the next commit.
We need to adjust them for U-Boot in the following commits.

To make it easier for reviewers to track the modification,
this commit renames scripts/Makefile.build to
scripts/Makefile.build.tmp beforehand.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: import more build scripts from Linux v3.13 tag

This commit imports build scripts from Linux Kernel v3.13
as they are.

I know they include some trailing spaces
but I am intentionally keeping them untouched.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>