[U-Boot] [PATCH V7 1/5] mv: seperate kirkwood and armada from common setting

[Lei Wen]

Hi Albert,

On Fri, Jan 28, 2011 at 2:47 PM, Albert ARIBAUD <albert.aribaud at free.fr> wrote:
> Hi Lei,
>
> Le 28/01/2011 02:28, Lei Wen a écrit :
>
>>>> diff --git a/arch/arm/include/asm/arch-kirkwood/config.h
>>>> b/arch/arm/include/asm/arch-kirkwood/config.h
>>>> new file mode 100644
>>>> index 0000000..7c6d63b
>>>> --- /dev/null
>>>> +++ b/arch/arm/include/asm/arch-kirkwood/config.h
>>>> @@ -0,0 +1,145 @@
>
> ...
>
>>>> +#ifndef CONFIG_SYS_KWD_CONFIG
>>>> +#define      CONFIG_SYS_KWD_CONFIG
>>>> $(SRCTREE)/$(CONFIG_BOARDDIR)/kwbimage.cfg
>>>
>>> What are the '$()' operators doing here ?
>>
>> This definition is served as generating kirkwood special image, which
>> I just move it from mv-common.h
>> $(obj)u-boot.kwb:       $(obj)u-boot.bin
>>                 $(obj)tools/mkimage -n $(CONFIG_SYS_KWD_CONFIG) -T
>> kwbimage \
>>                 -a $(CONFIG_SYS_TEXT_BASE) -e $(CONFIG_SYS_TEXT_BASE) -d
>> $<  $@
>
> What I would like to understand is, the '$(X)' macro expansion operator
> indeed has meaning and makes sense for some tools such as Make, but not for
> a C preprocessor or compiler. Is this  config.h file included by a makefile
> somehow?
>

Yes, it would be included by the makefile as below:
Makefile: line 471:
$(obj)include/autoconf.mk: $(obj)include/config.h

Take guruplug as example.
Its guruplug.h would be include in the include/config.h.
While guruplug would involve the mv-common.h, in which the
arch/arm/include/asm/arch-kirkwood/config.h would be included.

I know this maybe a little complicated, but that is what it works.

Best regards,
Lei