DT510: Ethernet — fec1 + KSZ9896 bring-up (Tier C1)

[ajlennon]

Parent tracking

Sub-issue of #2 (DT510 BSP bring-up plan).

Scope (Tier C1)

Bring up Ethernet on DT510: &fec1 (i.MX ENET) to Microchip KSZ9896 (RGMII + MDIO / DSA-style switch as per design).

Current state

• fec1: status = "disabled" in imx8mm-jaguar-dt510.dts.
• Risk: Wrong PHY/MDIO/DSA topology can hang boot or break link — plan calls for incremental bring-up (link before full bridge).

Work

• Confirm hardware topology vs SSOT (RGMII, MDIO address, reset GPIOs, switch port mapping).
• Model in DT: fec + PHY/switch nodes (microchip,ksz9477 / ksz9893 family — verify exact part and compatible strings against schematic + kernel).
• Enable CONFIG_* for DSA / relevant PHY drivers in linux-lmp-fslc-imx fragments as needed.
• Acceptance: stable boot, eth0 (or DSA slave interfaces) up, basic ping/iperf on bench.

References

• docs/DT510-BSP-PROJECT-PLAN.md §5 C1
• docs/DT510-HARDWARE-AUDIT-CHECKLIST.md

Assignees

Per parent #2: @ajlennon @ohull456