bxe: Detect SFP SC connector type

[adam.jaremko_freebsd_gmail.com]

Summary

Detect and support SFP modules with subscriber connectors, eg. GPON, EPON

[emaste]

do you have a reference (datasheet etc.) for this?

[adam.jaremko_freebsd_gmail.com]

In D40360#918955, @emaste wrote:

do you have a reference (datasheet etc.) for this?

Unfortunately, I do not. This patch series was put together in 2018 by poking registers based on obscure information from a defunct or now gated broadcom community forum listing (1) and github repository (2). The latter, I suspect has been renamed (3) and included register descriptors for the many bits at play. There is a linage to "Broadcom 2.5G" and the registers have remained pretty consistent between phys. The bxe source itself also references the registers and even 2.5G for alternative code paths to other configurations and phys, which helped to put two and two together.

1. https://community.brocade.com/t5/Ethernet-Switch/Establish-and-configure-SGMII-connection-on-BCM53134P-to-WAN/td-p/97704
2. https://github.com/Broadcom-Network-Switching-Software/SDKLT
3. https://github.com/Broadcom-Network-Switching-Software/OpenBCM