[U-Boot] [PATCH v3 5/7] kconfig: switch to single .config configuration

Simon Glass
2015-02-20T16:59:15Z

On 19 February 2015 at 22:24, Masahiro Yamada <yamada.m@jp.panasonic.com> wrote:
> 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 cbdd9a9737cc (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 b724bd7d6349 (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>

I notice with seaboard there is a bit of a code size different. But I
don't think this matters.

06: kconfig: switch to single .config configuration
arm: (for 1/1 boards) all -839.0 bss +4.0 rodata -27.0
spl/u-boot-spl:all +16.0 spl/u-boot-spl:data +16.0 text -816.0
seaboard : all -839 bss +4 rodata -27
spl/u-boot-spl:all +16 spl/u-boot-spl:data +16 text -816
u-boot: add: 1/-11, grow: 0/-1 bytes: 4/-1352 (-1348)
function old new delta
__div0 - 4 +4
__aeabi_idiv0 12 - -12
__lshrdi3 24 - -24
__ashldi3 24 - -24
__aeabi_llsr 24 - -24
__aeabi_llsl 24 - -24
__ashrdi3 26 - -26
__aeabi_uidivmod 26 - -26
__aeabi_lasr 26 - -26
__aeabi_idivmod 26 - -26
raise 28 - -28
__udivsi3 604 152 -452
__divsi3 660 - -660
spl-u-boot-spl: add: 0/0, grow: 1/0 bytes: 16/0 (16)
function old new delta
gdata 184 200 +16

Regards,
Simon