[PATCH net-next RFC v2 2/6] net: ethtool: Introduce ETHTOOL_LINK_MEDIUM_* values

[Kory Maincent]

On Wed, 22 Jan 2025 18:42:47 +0100
Maxime Chevallier <maxime.chevallier at bootlin.com> wrote:

> In an effort to have a better representation of Ethernet ports,
> introduce enumeration values representing the various ethernet Mediums.
> 
> This is part of the 802.3 naming convention, for example :
> 
> 1000 Base T 4
>  |    |   | |
>  |    |   | \_ lanes (4)
>  |    |   \___ Medium (T == Twisted Copper Pairs)
>  |    \_______ Baseband transmission
>  \____________ Speed
> 
>  Other example :
> 
> 10000 Base K X 4
>            | | \_ lanes (4)
>            | \___ encoding (BaseX is 8b/10b while BaseR is 66b/64b)
>            \_____ Medium (K is backplane ethernet)
> 
> In the case of representing a physical port, only the medium and number
> of lanes should be relevant. One exception would be 1000BaseX, which is
> currently also used as a medium in what appears to be any of
> 1000BaseSX, 1000BaseFX, 1000BaseCX and 1000BaseLX.



> -	__DEFINE_LINK_MODE_PARAMS(100, T, Half),
> -	__DEFINE_LINK_MODE_PARAMS(100, T, Full),
> -	__DEFINE_LINK_MODE_PARAMS(1000, T, Half),
> -	__DEFINE_LINK_MODE_PARAMS(1000, T, Full),
> +	__DEFINE_LINK_MODE_PARAMS_LANES(10, T, 2, 4, Half, T),
> +	__DEFINE_LINK_MODE_PARAMS_LANES(10, T, 2, 4, Full, T),
> +	__DEFINE_LINK_MODE_PARAMS_LANES(100, T, 2, 4, Half, T),
> +	__DEFINE_LINK_MODE_PARAMS_LANES(100, T, 2, 4, Full, T),


> -	__DEFINE_LINK_MODE_PARAMS(1000, KX, Full),
> -	__DEFINE_LINK_MODE_PARAMS(10000, KX4, Full),
> -	__DEFINE_LINK_MODE_PARAMS(10000, KR, Full),
> +	__DEFINE_LINK_MODE_PARAMS(1000, KX, Full, K),
> +	__DEFINE_LINK_MODE_PARAMS(10000, KX4, Full, K),
> +	__DEFINE_LINK_MODE_PARAMS(10000, KR, Full, K),

The medium information is used twice.
Maybe we could redefine the __DEFINE_LINK_MODE_PARAMS like this to avoid
redundant information:
#define __DEFINE_LINK_MODE_PARAMS(_speed, _medium, _encoding, _lanes, _duplex)

And something like this when the lanes are not a fix number:
#define __DEFINE_LINK_MODE_PARAMS_LANES_RANGE(_speed, _medium, _encoding,
_min_lanes, _max_lanes, _duplex)

Then we can remove all the __LINK_MODE_LANES_XX defines which may be
wrong as you have spotted in patch 1.

Regards,
-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com