[U-Boot] SWUpdate - U-Boot environment library dependency

[Marek Vasut]

On 11/20/2018 10:11 PM, Simon Goldschmidt wrote:
> On 04.09.2018 12:30, Andreas Reichel wrote:
>> Hi all,
>>
>> as Stefano Babic was so friendly and pointed out a few things already,
>> we come the following problematic points:
>>
>> For SWupdate to access U-Boot's environment, it uses code from U-Boot.
>> Before 2015, fw_env.c was copied - hence out of version control,
>> afterwards and since then, a lib.a produced by U-Boot has been used
>> and renamed to libubootenv.a to link against.
>>
>> However, this approach creates several difficulties:
>>
>> * Distros like Debian cannot provide a devel package for SWUpdate like
>>    u-boot-dev, since U-Boot has its default environment code compiled
>>    board-dependently and Debian needed it board-independent.
>>    If a board-independent libubootenv.a was provided without
>>    a specific default environment, the first update process would destroy
>>    the U-Boot environment if it had had bad CRC before.
>>    (Thanks Stefano for this good point).
>>
>> * If we have a board with U-Boot already preinstalled and want to
>>    compile SWUpdate for it, we need the sources of this very U-Boot to
>>    get the propper lib. For example in a debian-like build system we
>> had to
>>    compile U-Boot again, although it is already installed since we lack
>>    a dev package.
>>
>> * U-Boot does not provide any default means to install a development
>>    library. Thus anything we modify on-top might break with the next
>>    version.
>>
>> First proposal by Stefano and me would be to somehow split the default
>> environment from the library to have a board-independent component and
>> board specific data that is passed to U-Boot and SWUpdate somehow.
>>
>> Goal is to factor out U-Boot environment support for other software like
>> SWUpdate and not patching and hacking like its the case with recipes
>> as in
>> openembedded atm.
> 
> Has there been any progress in the SWupdate/fw_setenv integration? I
> thought I remember reading something about letting fw_setenv extract the
> environment from the U-Boot binary in the target, but I cannot find the
> thread. I do think the current situation should be improved, making
> fw_setenv independent of the target that is built.
> 
> And as this thread is on the swupdate group as well: I would prefer
> calling an external fw_setenv tool instead of linking in the static
> library libubootenv.a...

Wouldn't it make sense to have U-Boot build the env code as LGPL
library, in addition to executable ?

-- 
Best regards,
Marek Vasut