[U-Boot] [PATCH] km-powerpc: define CONFIG_PRAM to protect PHRAM and PNVRAM

[Valentin Longchamp <valentin.longchamp@keymile.com>]

Hi York,

On 08/12/2014 08:03 PM, York Sun wrote:
> On 07/18/2014 02:10 AM, Valentin Longchamp wrote:
>> Hello Wolfgang,
>>
>> On 07/17/2014 02:47 PM, Wolfgang Denk wrote:
>>> Dear Valentin,
>>>
>>> In message <1405599840-11984-1-git-send-email-valentin.longchamp@keymile.com> you wrote:
>>>> When u-boot initializes the RAM (early in boot) it looks for the "pram"
>>>> env variable to know which is area it cannot use.
>>>>
>>>> At this early boot stage, the "pram" env variable is not avaible yet
>>>> since it gets computed in set_km_env that gets called AFTER the RAM
>>>> initialization. If the "pram" env variable is not found, the default
>>>> CONFIG_PRAM value is used.
>>>
>>> Note that I am not objecting against this patch, but I highly
>>> recommend to fix your board - RAM initialization is actually pretty
>>> late in the init sequence, and you should have a valid envionment long
>>> before.
>>>
>>
>> Maybe my commit message is unclear about this. You are right, at the RAM
>> initialization time, there is a valid environment, and that's the case on our
>> board too.
>>
>> However, at the very first boot on a board, the environment is empty (or
>> unvalid) and the default one is used where this "pram" env variable is not
>> defined. That's why the CONFIG_PRAM is used in this case and it should be
>> defined. This is not going to be the case at any later boot if a valid
>> environment (with pram defined) is found and used.
>>
>> Best regards,
>>
> 
> 
> Valentin,
> 
> How about you update the commit message to
> explain you are defining the default CONFIG_PRAM for your board in case "pram"
> variable is not available?
> 

OK, I will do ... even though the commit message already does already state
that, just with more details when and why (there was just a missing precision
here, "when no valid environment was found") the "pram" env variable can be
undefined and why it is important for us to have such a value. But maybe that's
too much information ?

Valentin