Commit graph

24 commits

Author SHA1 Message Date
Tom Rini
83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00
Tom Rini
f32c864938 scripts/Makefile* Add SPDX-License-Identifier tag
A general best practice for SPDX is that Makefiles should have an
identifier, add these as everything else is currently covered.

Signed-off-by: Tom Rini <trini@konsulko.com>
2016-01-19 08:31:17 -05:00
Masahiro Yamada
98bd0e0d9b kbuild: sync with Linux 4.1
Update some build scripts to match Linux 4.1.  Commit-based syncing
was done so as not to break U-Boot specific changes.
The previous big sync was from Linux 3.18-rc1 by commit 176d098277
(kbuild: sync misc scripts with Linux 3.18-rc1).

The commits imported from Linux (some with adjustments) are:

[1] commit 9fb5e5372208973984a23ee6f5f025c05d364633
    Author: Robert Richter <rrichter@cavium.com>
    dts, kbuild: Factor out dtbs install rules to Makefile.dtbinst

[2] commit 371fdc77af44f4cb32475fd499e1d912ccc30890
    Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
    kbuild: collect shorthands into scripts/Kbuild.include

[3] commit a29b82326ed4eb5567b03c85b52c6891578d5a03
    Author: Michal Marek <mmarek@suse.cz>
    kbuild: Remove duplicate $(cmd) definition in Makefile.clean

[4] commit 1846dfbde3e8a53f3673dcb1c1b79fd9b3f8d40d
    Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
    kbuild: remove redundant -rR flag of hdr-inst

[5] commit 34948e0bbf98640fc1821751b01d2f0cd17d84d5
    Author: Michal Marek <mmarek@suse.cz>
    kbuild: Drop support for clean-rule

[6] commit a16c5f99a28c9945165c46da27fff8e6f26f8736
    Author: Michal Marek <mmarek@suse.cz>
    kbuild: Fix removal of the debian/ directory

[7] commit d0d38cd9e853db11e0242b3df4c9c3c4a663fbb4
    Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
    kbuild: use mixed-targets when two or more config targets are given

[8] commit dd33c03b18b3f2db791eb6a17c37d2de66e4de18
    Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
    kbuild: fix cc-ifversion macro

[9] commit 665d92e38f65d70796aad2b8e49e42e80815d4a4
    Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
    kbuild: do not add $(call ...) to invoke cc-version or cc-fullversion

[10] commit 6dcb4e5edf39e3b65a75ca76f087b2fdbee8a808
    Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
    kbuild: allow cc-ifversion to have the argument for false condition

[11] commit c0a80c0c27e5e65b180a25e6c4c2f7ef9e386cd3
    Author: Heiko Carstens <heiko.carstens@de.ibm.com>
    ftrace: allow architectures to specify ftrace compile options

[12] commit 0b24becc810dc3be6e3f94103a866f214c282394
    Author: Andrey Ryabinin <a.ryabinin@samsung.com>
    kasan: add kernel address sanitizer infrastructure

[13] commit 4218affdf57f938c04e3a916a9685ee27079f377
    Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
    kbuild: remove warning about "make depend"

[14] commit 77479b38e2f58890eb221a0418357502a5b41cd6
    Author: Nathan Rossi <nathan.rossi@xilinx.com>
    kbuild: Create directory for target DTB

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Robert Richter <rrichter@cavium.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Signed-off-by: Nathan Rossi <nathan.rossi@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2015-07-27 15:01:54 -04:00
Masahiro Yamada
e02ee2548a kconfig: switch to single .config configuration
When Kconfig for U-boot was examined, one of the biggest issues was
how to support multiple images (Normal, SPL, TPL).  There were
actually two options, "single .config" and "multiple .config".
After some discussions and thought experiments, I chose the latter,
i.e. to create ".config", "spl/.config", "tpl/.config" for Normal,
SPL, TPL, respectively.

It is true that the "multiple .config" strategy provided us the
maximum flexibility and helped to avoid duplicating CONFIGs among
Normal, SPL, TPL, but I have noticed some fatal problems:

[1] It is impossible to share CONFIG options across the images.
  If you change the configuration of Main image, you often have to
  adjust some SPL configurations correspondingly.  Currently, we
  cannot handle the dependencies between them.  It means one of the
  biggest advantages of Kconfig is lost.

[2] It is too painful to change both ".config" and "spl/.config".
  Sunxi guys started to work around this problem by creating a new
  configuration target.  Commit cbdd9a9737 (sunxi: kconfig: Add
  %_felconfig rule to enable FEL build of sunxi platforms.) added
  "make *_felconfig" to enable CONFIG_SPL_FEL on both images.
  Changing the configuration of multiple images in one command is a
  generic demand.  The current implementation cannot propose any
  good solution about this.

[3] Kconfig files are getting ugly and difficult to understand.
  Commit b724bd7d63 (dm: Kconfig: Move CONFIG_SYS_MALLOC_F_LEN to
  Kconfig) has sprinkled "if !SPL_BUILD" over the Kconfig files.

[4] The build system got more complicated than it should be.
  To adjust Linux-originated Kconfig to U-Boot, the helper script
  "scripts/multiconfig.sh" was introduced.  Writing a complicated
  text processor is a shell script sometimes caused problems.

Now I believe the "single .config" will serve us better.  With it,
all the problems above would go away.  Instead, we will have to add
some CONFIG_SPL_* (and CONFIG_TPL_*) options such as CONFIG_SPL_DM,
but we will not have much.  Anyway, this is what we do now in
scripts/Makefile.spl.

I admit my mistake with my apology and this commit switches to the
single .config configuration.

It is not so difficult to do that:

 - Remove unnecessary processings from scripts/multiconfig.sh
  This file will remain for a while to support the current defconfig
  format.  It will be removed after more cleanups are done.

 - Adjust some makefiles and Kconfigs

 - Add some entries to include/config_uncmd_spl.h and the new file
   scripts/Makefile.uncmd_spl.  Some CONFIG options that are not
   supported on SPL must be disabled because one .config is shared
   between SPL and U-Boot proper going forward.  I know this is not
   a beautiful solution and I think we can do better, but let's see
   how much we will have to describe them.

 - update doc/README.kconfig

More cleaning up patches will follow this.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2015-02-24 17:06:23 -05:00
Masahiro Yamada
176d098277 kbuild: sync misc scripts with Linux 3.18-rc1
This commit imports some updates in misc scripts from Linux 3.18-rc1.

[1] commit cbb4d3e6510b99522719c5ef0 by Horia Geanta
scripts/kernel-doc: handle object-like macros

[2] commit 164f0d2efaaef83 by Michal Marek
kbuild: Fix handling of backslashes in *.cmd files

[3] commit 270a00963cd367214e by Randy Dunlap
scripts/kernel-doc: recognize __meminit

[4] commit a4954fd7724c0f55361eb5 by Masahiro Yamada
  kbuild: remove obj-n and lib-n handling

[5] commit 5b2389b45d1a9c12b9f by Masahiro Yamada
kbuild: simplify build, clean, modbuiltin shorthands

Signed-off-by: Horia Geanta <horia.geanta@freescale.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-11-07 16:27:07 -05:00
Masahiro Yamada
cb6e7b0db9 kbuild: improve multi-objs dependency and cleanups
Since Linux 3.18-rc1, Kbuild is able to handle multi-objs
dependency correctly, which also allows us futher cleanups
of some makefiles.

This commit imports those commits:

[1] commit c8589d1e9e01 by Masahiro Yamada
kbuild: handle multi-objs dependency appropriately

[2] commit 97e3226e6e98 by Masahiro Yamada
kbuild: handle the dependency of multi-objs hostprogs appropriately

[3] commit 022af62d0190 by Masahiro Yamada
kbuild: refactor script/kconfig/Makefile

[4] commit 221ecca6cafe by Masahiro Yamada
kbuild: remove redundant clean-files from scripts/kconfig/Makefile

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-11-07 16:27:06 -05:00
Masahiro Yamada
6419e14492 kbuild: move extra gcc checks to scripts/Makefile.extrawarn
This commit was imported from Linux Kernel:
commit a86fe353 written by me.

W=... provides extra gcc checks.

Having such code in scripts/Makefile.build results in the same flags
being added to KBUILD_CFLAGS multiple times becuase
scripts/Makefile.build is invoked every time Kbuild descends into
the subdirectories.

Since the top Makefile is already too cluttered, this commit moves
all of extra gcc check stuff to a new file scripts/Makefile.extrawarn,
which is included from the top Makefile.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-08-21 12:01:11 -04:00
Masahiro Yamada
51148790f2 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>
2014-07-30 08:48:03 -04:00
Masahiro Yamada
45f0ad9545 cosmetic: kbuild: clean-up coding style (sync with Linux 3.16-rc1)
Import the following trivial commits from Linux v3.16-rc1:

 bb66fc6 kbuild: trivial - use tabs for code indent where possible
 7eb6e34 kbuild: trivial - remove trailing empty lines
 3fbb43d kbuild: trivial - fix comment block indent
 38385f8 kbuild: trivial - remove trailing spaces

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-06-20 11:56:26 -04:00
Masahiro Yamada
598e2d3388 kbuild: sync with Linux Kernel v3.15-rc1
This commit imports Kbuild-related updates
from v3.14 to v3.15-rc1.

 - commit 3d3d6b8474204b6819688c9800774d52d370a538
    kbuild: LLVMLinux: Adapt warnings for compilation with clang
 - commit 61163efae02040f66a95c8ed17f4407951ba58fa
    kbuild: LLVMLinux: Add Kbuild support for building kernel with Clang
 - commit 79192ca8ebd9a25c583aa46024a250fef1e7766f
    scripts: objdiff: detect object code changes between two commits
 - commit 1c9e70a55b088d97a59241744fe459409d0c3582
    kbuild: create a build directory automatically for out-of-tree build
 - commit a03fcb50e816a69acffb13b5e56db75063aeba8a
    kbuild: remove redundant '.*.cmd' pattern from make distclean
 - commit 13338935f1574a2dcd1c891461b0dcc42f8cff42
    kbuild: move "quote" to Kbuild.include to be consistent
 - commit bfdfaeae500a3b194b73b01e92a8034791a58b7f
    kbuild: specify build_docproc as a phony target
 - commit f4d4ffc03efc864645b990e1d579bbe1b8e358a4
    kbuild: dtbs_install: new make target
 - commit 1e64ff42ea3d8d2fc8aa71f9717b3c1cb6c2f893
    Kbuild, lto: Disable LTO for asm-offsets.c
 - commit ccbef1674a1579842c7dbdf554efca85d2cd245a
    Kbuild, lto: add ld-version and ld-ifversion macros
 - commit ae63b2d7bdd9bd66b88843be0daf8e37d8f0b574
    scripts/tags.sh: Ignore *.mod.c
 - commit e36aaea28972c57a32a3ba5365e61633739719b9
    kbuild: Fix silent builds with make-4

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-04-18 11:43:36 -04:00
Masahiro Yamada
026f9cf24f kbuild: improve Kbuild speed
Kbuild brought about many advantages for us but a significant
performance regression was reported by Simon Glass.

After some discussions and analysis, it turned out
its main cause is in $(call cc-option,...).

Historically, U-Boot parses all config.mk
(arch/*/config.mk and board/*/config.mk)
every time descending into subdirectories.
That means cc-options are evaluated over and over again.

$(call cc-option,...) is useful but costly.
So we want to evaluate them only in ./Makefile
and spl/Makefile and export compiler flags.

This commit changes the build system as follows:

  - Modify scripts/Makefile.build to not include config.mk
    Instead, add $(PLATFORM_CPPFLAGS) to asflags-y, ccflags-y,
    cppflags-y.

  - Export many variables
    Going forward, Kbuild will not parse config.mk files
    when it descends into subdirectories.
    If we want to set variables in config.mk and use them
    in subdirectories, they must be exported.

    This is the list of variables to get exported:
      PLATFORM_CPPFLAGS
      CPUDIR
      BOARDDIR
      OBJCOPYFLAGS
      LDFLAGS
      LDFLAGS_FINAL
        (used in nand_spl/board/*/*/Makefile)
      CONFIG_STANDALONE_LOAD_ADDR
        (used in examples/standalone/Makefile)
      SYM_PREFIX
        (used in examples/standalone/Makefile)
      RELFLAGS
        (used in examples/standalone/Makefile)

  - Delete CPPFLAGS
    This variable has been replaced with PLATFORM_CPPFLAGS

  - Copy gcclibdir from example/standalone/Makefile
    to arch/sparc/config.mk
    The reference in CONFIG_STANDALONE_LOAD_ADDR must be
    resolved before it is exported.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reported-by: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org> [on Sandbox]
Tested-by: Stephen Warren <swarren@nvidia.com> [on Tegra]
2014-03-07 10:59:06 -05:00
Masahiro Yamada
01072b44db 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>
2014-02-19 11:07:51 -05:00
Masahiro Yamada
6825a95b0b 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>
2014-02-19 11:07:50 -05:00
Masahiro Yamada
22433fc54b 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>
2014-02-19 11:07:50 -05:00
Masahiro Yamada
ec626f1139 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>
2014-02-19 11:07:50 -05:00
Masahiro Yamada
9e4140329e 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>
2014-02-19 11:07:50 -05:00
Masahiro Yamada
bf4b3de101 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>
2014-02-19 11:07:50 -05:00
Masahiro Yamada
5651ccffa4 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>
2014-02-19 11:07:50 -05:00
Masahiro Yamada
4a20df395d examples: Use scripts/Makefile.build
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-19 11:07:49 -05:00
Masahiro Yamada
ad71fa9971 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>
2014-02-19 11:05:13 -05:00
Masahiro Yamada
e5c5301f14 Makefile: make directories by Makefile.build
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2013-11-17 14:11:31 -05:00
Masahiro Yamada
3fdf5c8e94 Makefile: abolish COBJS, SOBJS, etc.
The support for COBJS, COBJS-y, SOBJS, SOBJS-y, GLCOBJS, GLSOBJS
from scripts/Makefile.build.
Going forward we need to use Kbuild style consistently.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2013-11-17 14:11:30 -05:00
Masahiro Yamada
ac7e735322 Makefile: support descending down to subdirectories
This patch tweaks scripts/Makefile.build to allow
the build system to descend into subdirectories like Kbuild.

To use this feature, use "obj-y += foo/" syntax.

Example:
    obj-$(CONFIG_FOO) += foo/

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
2013-10-31 13:26:44 -04:00
Masahiro Yamada
ce28d7ac6d Makefile: prepare for using Kbuild-style Makefile
Every makefile in sub directories has common lines
at the top and the bottom.
This commit pushes the common parts into script/Makefile.build.

Going forward sub-makefiles only need to describe this part:

    COBJS := ...
    COBJS += ...
    SOBJS := ...

But using obj-y is preferable to prepare for switching to Kbuild.

The conventional (non-Kbuild) Makefile style is still supported.
This is achieved by greping the Makefile before entering into it.
U-Boot conventional sub makefiles always include some other makefiles.
So the build system searches a line beginning with "include" keyword
in the makefile in order to distinguish which style it is.
If the Makefile include a "include" line, we assume it is a conventional
U-Boot style. Otherwise, it is treated as a Kbuild-style makefile.

With this tweak, we can switch sub-makefiles
from U-Boot style to Kbuild style little by little.

obj-y := foo/
syntax (descending into the sub directory) is not supportd yet.
It will be implemented in the upcomming commit.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@ti.com>
2013-10-31 12:53:39 -04:00