Re: Copyright and maintainability question for new ARM Cortex A9 HAL

[Jonathan Larmour <jifl@eCosCentric.com>]

On 05/09/13 04:52, Michael Jones wrote:
> 
> The status is:
> 
> - Project not registered yet

That's not an issue. Projects don't need to be registered.

> - Uses Freescale SDK macros
> - Uses Freescale SDK code for MMU, GIC, etc

Okay, the most important thing we need to know is the license for that
Freescale SDK. Is it Free (with a capital F) - in other words, it can be
distributed and redistributed freely by anyone in a way acceptable to the Free
Software Foundation (FSF)? That means really, is it one of the licenses here:
http://www.gnu.org/licenses/license-list.html#GPLCompatibleLicenses

If it is one of those licenses, that will probably mean it's okay (unless the
GPL exception clause in the eCos license causes some conflict). Furthermore,
we can directly incorporate any files you use directly into the port, avoiding
any problems with users having to build with an SDK which lives elsewhere.


> Before I register, I want to have a strategy in place to deal with
> Freescale code. Do I replace all the Freescale code line by line until
> nothing is left,

Assuming it needs to be replaced...

Replacing it line by line is risky. Copyright is about ideas, not just who
typed it in. If you use the same, or a sufficiently similar, API or design to
theirs, it risks infringing the copyright. Not only must it not be the API, it
must not be able to be considered to have been derived from the API.

In some cases, people have gone to the extent of "clean room" implementations
to avoid this sort of thing, but I don't think that's likely to be needed. But
really what's wanted is to effectively do what you would have done if the
Freescale SDK APIs hadn't been there. For some stuff, it can't really be done
any other way *anyway*, which is fine. For example, an interrupt controller
mask macro - there's probably only one particular way to do it. Although if,
for example, you named the function, and any local variables, exactly the same
way, that might be a problem. Hopefully replacement isn't relevant though.

> or see if Freescale will assign copyright?

That would certainly be easiest, however I don't think they're going to want
to assign copyright for their whole SDK! There can only be one owner of the
code, and it would mean it was no longer Freescale. So that really won't fly.
However, I think in this case we can have confidence that Freescale are the
owners of the code, and have the rights to redistribute; that's something we
have to be more cautious about with other contributors.

Jifl

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