[U-Boot] [PATCH] at91: board specific lowlevel_init.S

[Ilko Iliev <iliev@ronetix.at>]

Dear Jean,

Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 12:45 Tue 28 Oct     , Ilko Iliev wrote:
>   
>> Dear Jean-Christophe,
>>
>> Jean-Christophe PLAGNIOL-VILLARD wrote:
>>     
>>> On 22:20 Mon 27 Oct     , Wolfgang Denk wrote:
>>>   
>>>       
>>>> Dear Jean-Christophe PLAGNIOL-VILLARD,
>>>>
>>>> In message <20081027164336.GA1778@game.jcrosoft.org> you wrote:
>>>>     
>>>>         
>>>>>> I've found that weak functions are only overwritten if the overwriting 
>>>>>> function is in a file (not archive) that has strongly-linked symbols.  
>>>>>> Admittedly, I've only done this with C code but expect that the assembly 
>>>>>> equivalent works the same way.  The idea of using weak functions seems 
>>>>>> great, but suffers from some pretty cumbersome weaknesses :)
>>>>>>         
>>>>>>             
>>>>> I've found a solution but it's need to update the all u-boot linking method.
>>>>>
>>>>> Move from AR to LD.
>>>>>       
>>>>>           
>>>> Well, that is exactly what Ben just described.
>>>>
>>>>     
>>>>         
>>>>> Which need some work to fit on all boards.
>>>>>       
>>>>>           
>>>> Well, actually only the file lowlevel_init.o needs to be treated that
>>>> way, so the needed hcanges look not too complicated to me.
>>>>     
>>>>         
>>> I'll send a patch to move cpu/at91 to it only and an example to use it with
>>> board dir
>>>   
>>>       
> Could you try this
>
>
> diff --git a/config.mk b/config.mk
> index 5a9334c..0d81ab3 100644
> --- a/config.mk
> +++ b/config.mk
> @@ -80,6 +80,9 @@ STRIP	= $(CROSS_COMPILE)strip
>  OBJCOPY = $(CROSS_COMPILE)objcopy
>  OBJDUMP = $(CROSS_COMPILE)objdump
>  RANLIB	= $(CROSS_COMPILE)RANLIB
> +cmd_link_o_target = $(if $(strip $(2)),\
> +			$(LD) $(PLATFORM_LDFLAGS) -r -o $(1) $(2) ,\
> +			rm -f $@; $(AR) rcs $(1))
>  
>  #########################################################################
>  
> diff --git a/cpu/arm926ejs/at91/Makefile b/cpu/arm926ejs/at91/Makefile
> index 2d2a888..662657c 100644
> --- a/cpu/arm926ejs/at91/Makefile
> +++ b/cpu/arm926ejs/at91/Makefile
> @@ -36,7 +36,7 @@ OBJS    := $(addprefix $(obj),$(SOBJS) $(COBJS-y))
>  all:	$(obj).depend $(LIB)
>  
>  $(LIB):	$(OBJS)
> -	$(AR) $(ARFLAGS) $@ $(OBJS)
> +	$(call cmd_link_o_target, $@, $(OBJS))
>  
>  #########################################################################
>  
>
> and modify your board lib build by
> -	$(AR) $(ARFLAGS) $@ $(OBJS)
> +	$(call cmd_link_o_target, $@, $(OBJS))
>
> Best Regards,
> J.
>   

Your patch doesn't resolve the problem - the lowlevel_init.o is still a
part of libat91.s:
arm-elf-ld -r -o libat91.a lowlevel_init.o timer.o spi.o usb.o
make[1]: Leaving directory
`/home/develop/u-boot-last/u-boot/u-boot-2008-11-03/u-boot/cpu/arm926ejs/at91'

The attribute ".weak" works only if the file where is the weak function
is not in a library.
I'm not familiar with the makefile scripting, but I can't see a
possibility to link both lowlevel_init.o files into the u-boot.elf
without to change the main Makefile.

I think my last patch is a possible solution, but I don't know if the
following is a potential problem:

-               $(MAKE) -C cpu/$(CPU) $(if $(REMOTE_BUILD),$@,$(notdir $@))
+               $(MAKE) -C cpu/$(CPU)

I haven't the possibility to compile U-BOOT for all targets - maybe
someone can test all targets with my last patch (email from 28.10.2008).

-- 
Mit freundlichen Gruessen/With best regards,
Ilko Iliev
Ronetix Development Tools GmbH
CPU Modules, JTAG/BDM Emulators and Flash Programmers
Waidhausenstrasse 13/5, 1140 Vienna, Austria
E-Mail: iliev at ronetix.at; Web: www.ronetix.at