Aeluros 2005 PHY support in Linux-libre

Divy Le Ray divy at chelsio.com
Thu Dec 4 19:23:42 UTC 2008


Alexandre Oliva wrote:
> Hi,
>
> I've been staring at sr_edc and twinax_edc, in the patch you posted at
> http://lkml.org/lkml/2008/10/8/300
>
> I can see that, as copyright holder and manufacturer of the part,
> Chelsio is entitled to publish those sequences of bits however it
> likes.  However, I can't make sense of those bits to the point of being
> able to enjoy the right to modify that code, as granted by the GPL.
>
> Would it be possible to add any documentation as to what that sequence
> of numbers is supposed to mean?  I can't even convince myself it's just
> data; it has a regularity that resembles machine code, which makes me
> wonder if you just forgot to include the corresponding sources in the
> patch, which anyone else would be required to have in order to be able
> to redistribute it under the GPL (e.g. as part of Linux).
>
> Unsure whether redistributing those bits under the GPL is even legal,
> I'm taking them out of linux-libre for the time being, but I'd be glad
> to put it back in once I'm convinced the four freedoms are available as
> to that piece of code.
>
> Thanks in advance for any information you might be able to share in this
> regard,
>   

Hi Alexandre,

This sequence number represents a series on MDIO register writes to the 
PHY block.
This PHY supports different carrier modules - fiber or twinax,
and needs to be initialized differently depending on the module type 
inserted.

The sr_edc and twinax_edc tables are organized in (register,value) pairs,
which the driver writes this way:
    for (i = 0; i < ARRAY_SIZE(XX_edc) && !err; i += 2)
        err = mdio_write(phy, MDIO_DEV_PMA_PMD, twinax_edc[i],
                 twinax_edc[i + 1]);


Does it help?
Cheers,
Divy


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