[U-Boot] How to get GPL free standalone programs with u-boot

[U-Boot] How to get GPL free standalone programs with u-boot

[Neugebauer, Manfred]

Hallo,

I have a question concerning standalone programs based on u-boot and GPL, since I'm not really sure whether the way how the u-boot source files are set up allows GPL free standalone programs.

u-boot allows the use of standalone applications which can be loaded and executed by u-boot. These applications can use certain u-boot functions. There are several advantages of this approach. It also allows to build applications, which don't need to be released under GPL. In general, this looks good. And for certain tasks this is exactly what we need.

However, when looking at the GPL details, I'm not sure whether this really works with the current u-boot sources (from a legal point of view):

(a) the source code of the hello_world example for a standalone application has a GPL header. If you are legally strict, this can mean every standalone application is a derived work from this example and therefore restricted to GPL.

(b) When you want to write a standalone application you need  - as a minimum - to include "exports.h" (for the interface definitions), which requires "common.h" as additional header file. Both files are not included in the COPYING information which allows the use outside of GPL. The header file "common.h" (and other header files, which are included within common.h) even have a GPL header.

(c) you need to link your standalone application against stub.o (or the corresponding library). I did not find any statement (e.g., within stub.c), that this part is GPL-free (e.g., similar to LGPL).

So, from my point of view (although I'm not a lawyer), there are some doubts about a GPL free standalone application based on the actual u-boot sources. I believe there should be some enhancements to clarify this subject:

(1) GPL free standalone examples
(2) a really GPL free exports.h (similar to include/image.h)
(3) some explanations that the use of the source file "examples/standalone/stub.c" is not GPL restricted.

I know that this is a very strict view to this subject (but that is the way legal people look at it). I'm interested in a feedback from others who already were involved with this issue.


With best regards,
Manfred Neugebauer

Siemens AG
Industry Sector
Industry Automation Division
Advanced Technologies & Standards
mailto:manfred.neugebauer at siemens.com

Siemens Aktiengesellschaft: Chairman of the Supervisory Board: Gerhard Cromme; Managing Board: Peter Loescher, Chairman, President and Chief Executive Officer; Wolfgang Dehen, Heinrich Hiesinger, Joe Kaeser, Barbara Kux, Hermann Requardt, Siegfried Russwurm, Peter Y. Solmssen; Registered offices: Berlin and Munich, Germany; Commercial registries: Berlin Charlottenburg, HRB 12300, Munich, HRB 6684; WEEE-Reg.-No. DE 23691322

[U-Boot] How to get GPL free standalone programs with u-boot

[Wolfgang Denk]

Dear "Neugebauer, Manfred",

In message <1B9C02DB7C62FE44B8FAC992AAC75E8E16472581@DEFTHW99E85MSX.ww902.siemens.net> you wrote:
>
> I have a question concerning standalone programs based on u-boot and
> GPL, since I'm not really sure whether the way how the u-boot source
> files are set up allows GPL free standalone programs.

This is the intention; if the current code or documentation should
conflict with this intention, it should be fixed.

> However, when looking at the GPL details, I'm not sure whether this
> really works with the current u-boot sources (from a legal point of
> view):
> 
> (a) the source code of the hello_world example for a standalone
> application has a GPL header. If you are legally strict, this can
> mean every standalone application is a derived work from this example
> and therefore restricted to GPL.

I disagree.

You should be able to write standalone aplications without ever
looking at the hello_world.c file.

> (b) When you want to write a standalone application you need - as a
> minimum - to include "exports.h" (for the interface definitions),
> which requires "common.h" as additional header file. Both files are
> not included in the COPYING information which allows the use outside
> of GPL. The header file "common.h" (and other header files, which are
> included within common.h) even have a GPL header.

"exports.h" should be added to the "allowed" file list; there should
be no need to include "common.h". Eventually this needs fixing.
Patches are welcome.

> (c) you need to link your standalone application against stub.o (or
> the corresponding library). I did not find any statement (e.g.,
> within stub.c), that this part is GPL-free (e.g., similar to LGPL).

"examples/standalone/stubs.c" should be added to the "allowed" file
list (the ppc_*jmp.S files are LGPLed).

> So, from my point of view (although I'm not a lawyer), there are some
> doubts about a GPL free standalone application based on the actual

There should be no doubts - the intention is clear, the current state
may need improvement. Help (read: patches) welcome.

> u-boot sources. I believe there should be some enhancements to
> clarify this subject:
> 
> (1) GPL free standalone examples
> (2) a really GPL free exports.h (similar to include/image.h)
> (3) some explanations that the use of the source file
> "examples/standalone/stub.c" is not GPL restricted.

Agreed.

> I know that this is a very strict view to this subject (but that is
> the way legal people look at it). I'm interested in a feedback from
> others who already were involved with this issue.

There is two ways to deal with licenses: either ignore them
completely, or be really strict about them. I think we all agree that
we cannot ignore them, so we have little choice but trying to improve
what we have.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Build a system that even a fool can use and only a fool will want  to
use it.