Signed-off-by: Tom Rini <trini@ti.com>

include/generated/version_autogenerated.h was not correctly
generated on the parallel build (with -j option).

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reported-by: Andreas Bießmann <andreas.devel@googlemail.com>

"checkgcc4" is used only for PowerPC.
Move it to arch/powerpc/config.mk.

To make sure gcc is new enough before beginning build,
run "checkgcc4" during "archprepare".

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

"checkthumb" makes sense only for ARM architecture.
Move it to arch/arm/config.mk.

To make sure gcc supports THUMB mode before beginning build,
run "checkthumb" during "archprepare".

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

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]

Before this commit, USE_PRIVATE_LIBGCC was defined in
arch-specific config.mk and referenced in
arch/$(ARCH)/lib/Makefile.

We are not happy about parsing config.mk again and again.
We have to keep the same behavior with a different way.

By adding "CONFIG_" prefix, this macro appears
in include/autoconf.mk, include/spl-autoconf.mk.
(And treating USE_PRIVATE_LIBGCC as CONFIG macro
is reasonable enough.)

Tegra SoC family defined USE_PRIVATE_LIBGCC as "yes"
in arch/arm/cpu/arm720t/tegra*/config.mk,
whereas did not define it in arch/arm/cpu/armv7/tegra*/config.mk.

It means Tegra enables PRIVATE_LIBGCC only for SPL.
We can describe the same behavior by adding

  #ifdef CONFIG_SPL_BUILD
  # define CONFIG_USE_PRIVATE_LIBGCC
  #endif

to include/configs/tegra-common.h.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Tom Warren <twarren@nvidia.com>
Cc: Simon Glass <sjg@chromium.org>
Acked-by: Stephen Warren <swarren@nvidia.com>

config.tmp is never generated

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>

U-Boot has compelled all boards to have
board/${BOARD}/ or board/${VENDOR}/${BOARD}/ directory.

Sometimes it does not seem suitable for some boards,
for example Sandbox. (Is it a board?)

And arcangel4 board has nothing to compile
under the board directory.

This commit makes the build system more flexible:
If '<none>' is given to the 6th column (=Board name) of boards.cfg,
Kbuild will not descend into the board directory.

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

Programs in tools/ directory are usually built for the host.
But some of them (mkimage, dumpimge, gen_eth_addr, etc.) are
useful on the target OS too.

Actually, prior to Kbuild, U-Boot could build tools for
the target like follows:

  $ make <target_board>_config
  $ export CROSS_COMPILE=<cross_gcc_prefix>
  $ make HOSTCC=${CROSS_COMPILE}gcc HOSTSTRIP=${CROSS_COMPILE}strip tools

In Kbuild, we can no longer replace HOSTCC at the command line.

In order to get back that feature, this commit adds "cross-tools" target.

Usage:

  Build tools for the host
  $ make CROSS_COMPILE=<cross_gcc_prefix> tools

  Build tools for the target
  $ make CROSS_COMPILE=<cross_gcc_prefix> cross_tools

Besides, "make cross_tools" strip tools programs because we
generally expect smaller storages on embedded systems.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reported-by: Heiko Schocher <hs@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Tom Rini <trini@ti.com>
Tested-by: Heiko Schocher <hs@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>

The top Makefile must export HOST_TOOLS_ALL to use it
in tools/Makefile.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Heiko Schocher <hs@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>