[U-Boot-Users] PPC440GX reset command doesn't work

Renaud Barbier renaud.barbier at ge.com
Thu Sep 1 18:24:12 CEST 2005


Just saw that old email. I am haveing the sme problem with my 440GX.

Have you found any clue of why a system reset does not work?

Andrew Wozniak wrote:

>Andrew Wozniak wrote:
>  
>
>>We have a custom PPC440GX board running a ported version of U-Boot based
>>on the OCOTEA codebase. Most U-Boot commands are working - life is good.
>>
>>Except for the 'reset' command. The do_reset() source code at
>>cpu/ppc4xx/cpu.c appears to be the function for doing the reset via the
>>PPC "debug control register". The PPC manual shows that a cpu reset is
>>possible thru this register, but I'm a PPC assembly newbee and need to
>>figure it out the macros in the cpu.c source code.
>>
>>Just wondering if anyone else with a PPC440 target had any special
>>modifications to make 'reset' work.
>>    
>>
>
>Ok, understand the assembly macro (except for the ::: "r3"). Must have
>something to do with do_reset args?
>
>Anyway, it appears that a PPC "system reset" does not work as
>implemented via DBCR0 value 0x30000000.
>
>If I change the value to 0x20000000 to do a "chip reset", the U-Boot
>'reset' command works!
>
>Is this an appropriate solution or might our hardware design have a flaw?
>
>Thanks for all suggestions.
>
>  
>
>>Thank you.
>>    
>>
>
>
>
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