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

[Ilko Iliev]

Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 13:12 Wed 22 Oct     , Ilko Iliev wrote:
>   
>> Dear Mr. Denk,
>>
>>     
>>> Dear Ilko Iliev,
>>>
>>> In message <48FDFCA0.4090608 at ronetix.at> you wrote:
>>>   
>>>       
>>>>> Maybe instead of adding mor #ifdef'ery here, we can turn
>>>>> lowlevel_init() into a "weak" function that can be redefined by board
>>>>> specific code?
>>>>>       
>>>>>           
>>>> The lowlevel_init() is an assembler function called from another 
>>>> assembler function and the attribute .weak doesn't work.
>>>>     
>>>>         
>>> What do you mean by "attribute .weak doesn't work" ?
>>>
>>>   
>>>       
>>>> There are no assembler file in the U-BOOT tree which use weak functions.
>>>> Do you know how can I make an assembler function weak?
>>>>     
>>>>         
>>> Well, if you don't know, then don't ask me, ask your compiler - he
>>> knows how to do this.
>>>
>>> For example, common/cmd_boot.c has this code snippet right at the
>>> beginning:
>>>
>>>  30
>>>  31 /* Allow ports to override the default behavior */
>>>  32 __attribute__((weak))
>>>  33 unsigned long do_go_exec (ulong (*entry)(int, char *[]), int argc, char *argv[])
>>>  34 {
>>>  35         return entry (argc, argv);
>>>  36 }
>>>
>>> Compile this with -S option, and you get this:
>>>
>>>  12 .Ltext0:
>>>  13         .align 2
>>>  14         .weak   do_go_exec
>>>  15         .type   do_go_exec, @function
>>>  16 do_go_exec:
>>>  17 .LFB87:
>>>  18         .file 1 "cmd_boot.c"
>>>  19         .loc 1 34 0
>>>  20 .LVL0:
>>>  21         mflr 0
>>>  22 .LCFI0:
>>>  23         stwu 1,-16(1)
>>> ...
>>>
>>>
>>> So to me it seems as if the attribute .weak is supposed to work just fine.
>>>
>>> What exactly is not working for you?
>>>
>>>   
>>>       
>> With ".weak lowlevel_init" the function is marked as weak (I can see 
>> this in the ELF file) but it is not overwritten from the another 
>> lowlevel_init().
>>     
> try
> .weak __default_lowlevel_init = lowlevel_init
>
>   
I tried and the result is:
lowlevel_init.S:32: Error: junk at end of line, first unrecognized 
character is `='

I' using arm-elf-gcc 4.1.1


-- 
Mit freundlichen Grüßen/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