[U-Boot] [PATCH 1/4] doc: Add documentation for mpc85xx debugger support

[Prabhakar Kushwaha <prabhakar@freescale.com>]

Hi Scott,

On Thursday 15 March 2012 01:00 AM, Scott Wood wrote:
> On 03/14/2012 04:35 AM, Prabhakar Kushwaha wrote:
>> Hi Wolfgang,
>>
>> On Tuesday 13 March 2012 12:44 PM, Prabhakar Kushwaha wrote:
>>> Hi Wolfgang,
>>>
>>> On Wednesday 07 March 2012 06:00 PM, Wolfgang Denk wrote:
>>>> Dear Prabhakar Kushwaha,
>>>>
>>>> In message<4F572159.9020303@freescale.com>   you wrote:
>>>>>> Also, what's the "V1_V2" ? Are there also other systems (say, e500 v3
>>>>>> cores), and are this not affected? We already have CONFIG_E500 and
>>>>>> CONFIG_E500MC so CONFIG_E500_V1_V2 appears to belong to this group,
>>>>>> but if I understand your intentions it does something completely
>>>>>> unrelated.
>>>>> V1_V2 is used because it applied to e500v1 and e500v2 not e500mc
>>>>> processor. So CONFIG_E500MC cant be used. Also I cant use
>>>>> CONFIG_E500 as
>>>>> it refer the entire e500 family which includes e500mc.
>>>> Hm... I am not sure if CONFIG_E500 was supposed to include
>>>> CONFIG_E500MC; it's nowhere documented.  Let's assume it is.
>>>>
>>>> What happens if you enable this code on a E500MC system?
>>>>
>>> Debug  restrictions are not valid for e500mc system.
>>>
>>> At first sight it should not hurt e500mc execution (other than some
>>> seemingly unnecessary steps). However i will check this point.
>>>
>> We tried by enabling CONFIG_E500_V2_V2 for E500MC with u-boot patches.
>> It boots fine and debugging can be done.
> Be sure to mention in comments that the hack is only really needed for
> v1/v2.

I will clearly mention in doc

>> So, we can use CONFIG_E500 #define instead of CONFIG_E500_V2_V2 i.e.
>> debugging will always be enabled. One have to define
>> CONFIG_DEBUGGER_TEMP_TLB  for debugging in AS1 ( Part of patch
>> "powerpc/85xx:Update NOR code base to support debugger" )
> CONFIG_SYS_PPC_E500_DEBUG_TLB

OK

>> CONFIG_DEBUGGER_TEMP_TLB can also be used for placing code which can
>> only be required during debugging (specially code of temporary TLB
>> creation)
> Is there something specific you had in mind, other than the use that is
> already present in this patchset?

There is no specific use case in my mind other than the patch-set.

Actually, Wolfgang is having concern about code size increase because of 
"temporary TLB creation" in start.S for debugging.  That's why i am 
planning to use this #define for "temporary TLB creation"

--Prabhakar