Re: [PATCH net-next 1/2] ethtool: Add support for 100Gbps per lane link modes

[Meir Lichtinger <meirl@mellanox.com>]

On 02-May-20 18:08, Andrew Lunn wrote:
> On Thu, Apr 30, 2020 at 04:41:05PM -0700, Saeed Mahameed wrote:
>> From: Meir Lichtinger <meirl@mellanox.com>
>>
>> Define 100G, 200G and 400G link modes using 100Gbps per lane
>>
>> Signed-off-by: Meir Lichtinger <meirl@mellanox.com>
>> CC: Andrew Lunn <andrew@lunn.ch>
>> Reviewed-by: Aya Levin <ayal@mellanox.com>
>> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
>> ---
>>   drivers/net/phy/phy-core.c   | 17 ++++++++++++++++-
>>   include/uapi/linux/ethtool.h | 15 +++++++++++++++
>>   net/ethtool/common.c         | 15 +++++++++++++++
>>   net/ethtool/linkmodes.c      | 16 ++++++++++++++++
>>   4 files changed, 62 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
>> index 66b8c61ca74c..a71fc8b18973 100644
>> --- a/drivers/net/phy/phy-core.c
>> +++ b/drivers/net/phy/phy-core.c
>> @@ -8,7 +8,7 @@
>>   
>>   const char *phy_speed_to_str(int speed)
>>   {
>> -	BUILD_BUG_ON_MSG(__ETHTOOL_LINK_MODE_MASK_NBITS != 75,
>> +	BUILD_BUG_ON_MSG(__ETHTOOL_LINK_MODE_MASK_NBITS != 90,
>>   		"Enum ethtool_link_mode_bit_indices and phylib are out of sync. "
>>   		"If a speed or mode has been added please update phy_speed_to_str "
>>   		"and the PHY settings array.\n");
>> @@ -78,12 +78,22 @@ static const struct phy_setting settings[] = {
>>   	PHY_SETTING( 400000, FULL, 400000baseLR8_ER8_FR8_Full	),
>>   	PHY_SETTING( 400000, FULL, 400000baseDR8_Full		),
>>   	PHY_SETTING( 400000, FULL, 400000baseSR8_Full		),
>> +	PHY_SETTING( 400000, FULL, 400000baseCR4_Full		),
>> +	PHY_SETTING( 400000, FULL, 400000baseKR4_Full		),
>> +	PHY_SETTING( 400000, FULL, 400000baseLR4_ER4_FR4_Full	),
> Hi Mier, Saeed.
>
> Could you explain this last one? Seems unlikely this is a 12 pair link
> mode. So i assume it is four pair which can do LR4, ER4 or FR4?
Correct
> Can
> you connect a 400000baseLR4 to a 400000baseER4 with a 10Km cable and
> it work?

LR, ER & FR are using same technology – single mode fiber, w/WDM –

and by design are fully interoperable but haven’t tested all combinations.

> How do you know you have connected a 400000baseLR4 to a
> 400000baseER4 with a 40Km and it is not expected to work, when looking
> at ethtool? I assume the EEPROM contents tell you if the module is
> LR4, ER4, or FR4?
>
>       Andrew
Correct.

In addition, this is the terminology exposed in 50 Gbps and we followed it.


Meir