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>
kbuild: use Linux Kernel build scripts

Now we are ready to switch over to real Kbuild.

This commit disables temporary scripts:
  scripts/{Makefile.build.tmp, Makefile.host.tmp}
and enables real Kbuild scripts:
  scripts/{Makefile.build,Makefile.host,Makefile.lib}.

This switch is triggered by the line in scripts/Kbuild.include
  -build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build.tmp obj
  +build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj

We need to adjust some build scripts for U-Boot.
But smaller amount of modification is preferable.

Additionally, we need to fix compiler flags which are
locally added or removed.

In Kbuild, it is not allowed to change CFLAGS locally.
Instead, ccflags-y, asflags-y, cppflags-y,
CFLAGS_$(basetarget).o, CFLAGS_REMOVE_$(basetarget).o
are prepared for that purpose.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Gerhard Sittig <gsi@denx.de>
kbuild: delete temporary build scripts

We had switched to Kbuild.
We do not need old build scripts any more.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: move some lines to more suitable place

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: convert some make rules to Kbuild style

We can get Kbuild-ish log style like this:
  GEN     include/autoconf.mk
  GEN     include/autoconf.mk.dep

We do not need XECHO any more.

And also change checkstack target like Linux Kernel.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: move include directives of board configuration files

This commit changes the location of include directives
of board configuration files.

The purpose of this change is:
 - Slim down $(TOPDIR)/config.mk
 - Prevent $(TOPDIR)/Makefile from including the same
    configuration file twice
 - Do not include include/config.mk multiple times
    because ARCH, CPU, BOARD, VENDOR, SOC are exported

Before this commit:

 - include/autoconf.mk was included from $(TOPDIR)/Makefile
   and $(TOPDIR)/config.mk
   (This means $(TOPDIR)/Makefile included include/autoconf.mk twice)

 - include/{spl,tpl}-autoconf.mk was included from $(TOPDIR)/config.mk

 - include/config.mk was included from $(TOPDIR)/Makefile
   and $(TOPDIR)/config.mk
   (This means $(TOPDIR)/Makefile included include/config.mk twice)

After this commit:

 - include/autoconf.mk is included from $(TOPDIR)/Makefile
   and $(TOPDIR)/scripts/Makefile.build

 - include/{spl,tpl}-autoconf.mk is included from $(TOPDIR)/spl/Makefile
   and $(TOPDIR)/scripts/Makefile.build

 - include/config.mk is included from $(TOPDIR)/config.mk and
   $(TOPDIR)/spl/Makefile

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: generate {spl, tpl}-autoconf.mk only when it is necessary

Before this commit, {spl,tpl}-autoconf.mk was always generated
at the top Makefile even if SPL(TPL) build was not selected.

This commit moves the build rule of {spl,tpl}-autoconf.mk
from the top Makefile to spl/Makefile.
It prevents unnecessary {spl,tpl}-autoconf.mk from being
generated.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: remove a cleaning target "tidy"

Before this commit, "make tidy" did
"make clean" + delete "*.depend*" files.

But, we do not have "*.depend*" files any more,
which means "make tidy" is the same as "make clean".

This commit removes the redandant target "tidy".

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: change the top Makefile to more Kbuild-ish structure

This commit changes the top Makefile to handle various targets
nicely.
Make targets are divided into four categories:

 - mixed-targets
     We can call a configuration target and build targets
     at one command line like follows:
     $ make <board_name>_config u-boot

     They are handled one by one.

 - config targets
     <board_name>_config

 - no-dot-config-targets
     Targets we can run without board configuration such as
       clean, mrproper, distclean, TAGS, %docs, etc.

 - build targets
     The other target which need board configuration.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
examples: move api/ and standalone/ entry to examples/Makefile

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: refactor Makefile and spl/Makefile more

This commit refactors rules of directory descending
and defines u-boot-dirs and u-boot-all-dirs.
(We will need u-boot-all-dirs when using
scripts/Makefile.clean)

Additionally, rename LIBS-y to libs-y.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: Do not pass MTD_VERSION from the top Makefile

$(MTD_VERSION) is used in tools/env/Makefile

If you specify a variable at a command line like:
  $ make MTD_VERSION=old env
or specify it thru an envrionment variable like:
  $ export MTD_VERSION=old
  $ make env
it is inherited to the sub-make too.
We do not need to pass it from the top Makefile explicitely.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Makefile: refactor tools-all targets

- Move "easylogo", "gdb" tagets to tools/Makefile
 - Delete "gdbtools" target (same as "gdb")

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: use scripts/Makefile.clean

This commit refactors cleaning targets such as
clean, clobber, mrpropper, distclean
with scripts/Makefile.clean.

By using scripts/Makefile.clean, we can recursively descend
into subdirectories and delete generated files there.

We do not need add a big list of generated files
to the "clean" target.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: support simultaneous board configuration and "make all"

This commit fixes two problems:

[1] We could not do board configuration and "make all"
    in one command line.

For example, the following did not work as we expect:
  $ make sandbox_config all
  Configuring for sandbox board...
  make: Nothing to be done for `all'.

[2] mixed-target build did not work with -j option

For example, the following did not work:
  $ make -j8 sandbox_config u-boot
  Makefile:481: *** "System not configured - see README".  Stop.
  make: *** [u-boot] Error 2
  make: *** Waiting for unfinished jobs....
  Configuring for sandbox board...

Going forward, we can do
  $ make -j8 sandbox_config all

This is the same as
  $ make sandbox_config
  $ make -j8

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: check clean source and generate Makefile for out-of-tree build

For out-of-tree build
  - Check if the source tree is clean
  - Create a Makefile in the output directory

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