[U-Boot] [PATCH 00/18] Third step towards Kbuild: Convert rest of makefiles

[Marek Vasut]

Dear Masahiro Yamada,

> This series uses the followings as prerequisites:
>  - First step towards Kbuild: Use Kbuild style makefiles (19 patch files)
>  - Second step towards Kbuild: Descend down like Kbuild (6 patch files)
> 
> In 'First step towards Kbuild' series, I changed more than 150 makefiles.
> And in this series, I have changed the remainders, more than 600 makefiles.
> 
> After applying first step thru third step, all makefiles under
> arch/, board/, drivers/, api/, common/, disk/, dts/,
> fs/, lib/, net/, post/, test/
> are converted to Kbuild style.
> 
> ( doc/, tools/, nand_spl/, example/ have not been changed yet.
> I'm planning to convert these directories.
> But I need something prepared before that: hostprogs-y, etc.)
> 
> 
> Before converting makefiles to Kbuild style,
> I want to fix some makefile.
> This is done in 01/18 and 02/18.
> 
> 
> 01/18 fixes the link error of sparc architecture.
> Please see the snippet of arch/sparc/lib/Makefile:
> 
> 
>     LIB     = $(obj)lib$(ARCH).o
> 
>     SOBJS   =
> 
>     COBJS   = board.o cache.o interrupts.o time.o
>     COBJS-$(CONFIG_CMD_BOOTM) += bootm.o
> 
>     SRCS    := $(SOBJS:.o=.S) $(COBJS:.o=.c)
>     OBJS    := $(addprefix $(obj),$(SOBJS) $(COBJS))
> 
>     $(LIB): $(obj).depend $(OBJS)
>             $(call cmd_link_o_target, $(OBJS))
> 
> 
> Both COBJS and COBJS-y are used.
> But this makefile missed to add $(COBJS-y) to OBJS.
> So, bootm.o is never compiled.
> 
> Here, you will notice the advantage of switching to Kbuild style.
> 
> Makefiles in sub-directories have very similar form.
> But there exists a slight difference for each Makefile.
> 
> For ex. some makefiles use COBJS and the others use COBJS-y.
> Some use both of them mixed, and sometimes a mistake like above happens.
> We should use consistently use obj-y, for both C and Assembler objects.
> 
> 
> 02/18 fixes arch/sh/cpu/{sh2,sh3,sh4}/Makefile.
> The snippet is as follows:
> 
>     LIB     = $(obj)lib$(CPU).o
> 
>     SOBJS   = start.o
>     COBJS   = cpu.o interrupts.o watchdog.o
> 
>     SRCS    := $(SOBJS:.o=.S) $(COBJS:.o=.c)
>     OBJS    := $(addprefix $(obj),$(COBJS))
>     SOBJS   := $(addprefix $(obj),$(SOBJS))
> 
>     $(LIB): $(OBJS) $(SOBJS)
>             $(call cmd_link_o_target, $(OBJS) $(SOBJS))
> 
> start.o is linked into lib$(CPU).o, but it shouldn't.
> 
> 
> 03/18 thru 15/18 convert arch-specific, board-specific makefiles.
> 
> 
> 16/18, 17/18 convert commonly used directories.
> 
> 16/18 shows another big advantage of switching to Kbuild style.
> Check how simply post/Makefile was re-written by using
>   obj-$(CONFIG-FOO) += foo/
> systax.
> 
> 
> 18/18 convert the rest of makefiles and abolishes the support
> for U-Boot conventional makefile.
> After this commit, we cannot use U-Boot style makefiles any more.
> (exception: doc/, tools/, nand_spl/, example/ directory)
> Going forward, we must use only Kbuild style makefiles.
> Take care when you add a new makefile!
> 
> 
> Of course, I tested carefully this series.
> I built as many boards as possible over all architectures.
> 
> Here is the site I downloaded the prebuilt crosstools from:
> 
>   - arm, avr32, m68k, mips, openrisc, powerpc, x86:
>       ftp://ftp.kernel.org/pub/tools/crosstool/files/bin/x86_64/
> 
>   - blackfin, microblaze, nds32, nios2, sh, sparc:
>       http://dev.gentoo.org/~vapier/u-boot/
> 
> 
> I could not build some boards because the boards are
> already broken before this series or the crosstools are not suitable.
> But I could build more than 1100 target boards and
> I confirmed this series does no harm.
> 
>  -  02 thru 18 did not break any boards.
>  -  02 thru 15 and 17, 18 did not change output ELF files at all.
>     This was check by comparing md5sum.
>  -  It was difficult to simply compare md5sum for patch 16
>     because it changes how the objects are linked under post/ directory.
>     But I confirmed 16 did not change the section size.
> 
> Note:
> For comparing md5sum, there are some items you should take into account:
> Disabling time stamp, version, compiling in the same path, linking the
> objects in the same order...
> For detailed, refer to
> [U-Boot] [PATCH 00/19] First step towards Kbuild: Use Kbuild style
> makefiles Message-Id: <20130917093533.738A.AA925319 at jp.panasonic.com>
> 
> 
> Note2:
> I confirmed this series can be applied on
> v2013.10 tag
>  + First step towards Kbuild: Use Kbuild style makefiles (19 patch files)
>  + Second step towards Kbuild: Descend down like Kbuild (6 patch files)
> 
> 
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Tom Rini <trini at ti.com>
> Cc: Wolfgang Denk <wd at denx.de>
> Cc: Gerhard Sittig <gsi at denx.de>
[...]

Reviewed-by: Marek Vasut <marex at denx.de>