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

[Jean-Christophe PLAGNIOL-VILLARD]

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

IIRC

Best Regards,
J.