[U-Boot] [PATCH 11/21] i386: Generic system restart support

[Graeme Russ]

Hi Kyle

On Tue, Mar 8, 2011 at 9:06 AM, Moffett, Kyle D
<Kyle.D.Moffett at boeing.com> wrote:
> Hi!
>
> On Mar 07, 2011, at 16:54, Graeme Russ wrote:
>> On Tue, Mar 8, 2011 at 4:37 AM, Kyle Moffett <Kyle.D.Moffett at boeing.com> wrote:
>>> The i386 port has its own reset_cpu() dispatch for its various supported
>>> CPU families, so the existing do_reset() function is simply altered to
>>> use the new prototype for __arch_restart().
>>>
>>> In addition, the debug message and delay are duplicated from the generic
>>> code, so they are removed.
>>>
>>> This reset code will probably work even when the CPU is in a bad state,
>>> so no separate __arch_emergency_restart() function is required.
>>
>> This part does not make much sense - If the CPU is in 'a bad state' then
>> it will probably be lights out anyway. As I understand it, an emergency
>> restart is a restart not initiated by the user (divide by zero, unhandled
>> exception etc), in which case i386 will make use of it
>
> I was considering unhandled exceptions, etc. to be "a bad state" :-D.
>
> Maybe I didn't explain it well enough in the patch summary, but basically the default for "__arch_emergency_restart()" is to just call "__arch_restart()".  Since the i386 "__arch_restart()" function should work fine even when U-Boot is in trouble, that architecture does not need to override the default.
>
> Hopefully I am making sense now?  Should I reword it from "when the CPU is in a bad state" to "when U-Boot is in trouble", or is there something else that would be easier to understand?
>

I understand what you are doing now, thanks.

I think you can scrap this part of the description and I will have i386
start using __arch_emergency_restart() for 'Internal U-Boot Errors' such
as divide by zero, unhandled exception, general protection faults etc

I don't particularly like the 'emergency' naming - It's like if we don't
do it things will blow up :) I think 'automatic' might be a closer term

Is there anywhere yet where the code paths for the emergency and non
emergency variants differ in the way they end up resetting the board?

Regards,

Graeme