Reset cause API

[alayrac]

The PPC405 recognizes three types of reset:
• Aprocessor reset affects the processor only, including the execution
units and cache units. External devices (on-chip and off-chip) are not
affected. This type of reset is sometimes referred to as a core reset.
• Achip reset affects the processor and all other devices or peripherals
located on the same chip as the processor.
• Asystem reset affects the processor chip and all other devices or
peripherals external to the processor chip that are connected to the
same system-reset network. The scope of a system reset depends on the
system implementation.

The type of reset is recorded in the most-recent reset field of the
debug-status register (DBSR[MRR]). System software can examine this
field if it needs to determine the cause of a reset. The effect of a
reset on the processor is always the same regardless of the type.

For more details you can see ppc-ref-guide.pdf (in EDK doc directory).
Chris

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<----> -----Message d'origine-----
<----> De : linuxppc-embedded-
<----> bounces+christophe.alayrac=cresitt.com at ozlabs.org
[mailto:linuxppc-
<----> embedded-bounces+christophe.alayrac=cresitt.com at ozlabs.org] De la
<----> part de Kumar Gala
<----> Envoyé : jeudi 8 mars 2007 15:30
<----> À : bwarren at qstreams.com
<----> Cc : linuxppc-embedded at ozlabs.org
<----> Objet : Re: Reset cause API
<----> 
<----> 
<----> On Mar 5, 2007, at 3:22 PM, Ben Warren wrote:
<----> 
<----> > Hello,
<----> >
<----> > Is there an API call, either Linux or PowerPC-specific, for
<----> > determining
<----> > the cause of the last reset?  I can certainly read the RSR
myself,
<----> but
<----> > why bother if the information's available elsewhere.
<----> 
<----> There isnt anything like this since we don't have any consistent
way
<----> of maintaining information across a reset.
<----> 
<----> Something like kexec could possibly do something.
<----> 
<----> - k
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