[U-Boot-Users] clarifications u-boot for arm

[Russell Peterson]

Hello,

The answer to your question "who calls start_armboot?"  is answered by you
ASM code below.  Hint... take a close look at the regsiter you are loading.

:-)

Regards,

Russell


On 7/14/06, Ram <vshrirama at gmail.com> wrote:
>
> Hi,
>   Thanks for your response. I have gone much further and would like to
> know If
>
>      ldr pc, _start_armboot
>     _start_armboot:
>         .word start_armboot
>
>
>    Does this really invoke start_armboot?.  This is because
> _start_armboot is what is
>    stored in pc and not start_armboot and there is also a branch
> point _start_armboot (underscore start_armboot) Please see above.
>
>   Actually the above declares a variable start_armboot and does not
> invoke the function
>   start_armboot. If this is true, then who calls start_armboot?
>
>
>    According to me start_armboot ( ) which is present in
> lib_arm/board.c never returns until u reset the board and probably
> should be one of the last functions that needs to be called.
>
>    Correct?.
>
>
>   Rest agreed, What i have understood is
>         First,  reset is called which set the cpu to SVC32 mode and
> calls cpu_init_crit
>         which inturn calls lowlevel_init to setup memory and board
> specific register values.
>
>          Then stack is setup and start_amboot is called.
>
>
>          start_armboot is the point of entry where code is C. ie
> (Assembly to C) begins from start_armboot.
>
>
>          am i Correct?.
>
>
>        This is the function which does some remaining initialisation
> and then starts initialising the for pheripherals.
>
>
>     am i Correct?
>
>
> I didnt understand the things relating interrupt and thier processing
> though.
>
> Thanks and Regards,
> sriram
>
>
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