[U-Boot] [PATCH] env: Setup GD_FLG_ENV_DEFAULT flag when default environment are used

[Alexander Graf]

On 31.05.16 09:40, Michal Simek wrote:
> On 31.5.2016 08:39, Alexander Graf wrote:
>>
>>
>>> Am 31.05.2016 um 07:04 schrieb Michal Simek <michal.simek at xilinx.com>:
>>>
>>>> On 30.5.2016 21:36, Alexander Graf wrote:
>>>>
>>>>
>>>>> On 05/30/2016 04:11 PM, Michal Simek wrote:
>>>>> Setup flag when default environment are used to be able to
>>>>> rewrite default distro boot variables based on SoC boot mode.
>>>>>
>>>>> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
>>>>> ---
>>>>>
>>>>> I didn't find any way how to detect that default or saved variables are
>>>>> used. I want to have a flag to be able to rewrite boot_targets variable
>>>>> based on boot mode. Especially when SD boot mode is setup than SD should
>>>>> be primary boot devices, etc.
>>>>> When variables are saved boot_targets will be restored and SoC boot mode
>>>>> will be ignored.
>>>>> If you know better way how to do it, please let me know.
>>>>
>>>> You may want to be able to do the same from inside a script, so I guess
>>>> we should better have this as an environment variable itself again.
>>>
>>> Was there any environment in past?
>>
>> With again I meant "from C as well as from script".
>>
>>>>
>>>> There was a way to have environment variable reads return a value
>>>> directly from code rather than go via environment storage. I guess we
>>>> could expose the flag through that?
>>>
>>> If you expose environment variable and then run saveenv this variable
>>> will be saved and restored again and your script behaves the same.
>>
>> Not if we declare the environment variable read as callback ;).
> 
> What do you mean?

Meh, apparently I misremembered.

> It is kind of interesting that this is not done already for others SoCs
> when you want to use distro config. :-)

Well, there's always a first :).

Either way, I guess your patch is perfectly fine as a first step. It
would be nice to also introduce some way for scripts to evaluate whether
the environment is the default environment, but we can always add that
later.


Alex