[PATCH v2] boot: add support for button commands

[Michael Walle]

Hi,

> Using CONFIG_EXTRA_ENV_SETTINGS should be good enough to provide
> the fallback defaults.  However, the users can still mess the things 
> up,
> but again, they can do that already in many places.

I disagree. In my case that is a last resort recovery. And it should
work in any case. Even if the user has messed up anything (except
from erasing the bootloader in the SPI flash ;)).

>> In summary, the registered (compiled-in) command should always take
>> precedence. If one wants to supply a default command which can be
>> changed later, that can go via the (compiled-in) default environment.
> 
> Sorry, this is a bit confusing to me.  Didn't you write above that
> the users should be able to change the associated commands through
> the environment variables?

I had two kinds of button commands in mind: immutable ones and mutable
ones. The first can be achieved with compiled-in commands, the second
with a default environment and environment variables.

Also, whether a command is a mutable one or not is the decision of
the developer (or the one who's compiling/configuring u-boot),
not the user.

-michael