RDC R6040 Fast Ethernet MAC for R-321x SoCs
A 100 Mbps Ethernet controller built into RDC's R-321x x86-compatible system-on-chip processors, used in low-cost embedded boards and small home routers in the late 2000s and early 2010s, including hobbyist devices like the Bifferboard and the D-Link DIR-450.
recommendation
A candidate for future removal because the RDC R-321x system-on-chip family it supports has been off the market for over a decade and survives mainly in obscure legacy embedded boards like Bifferboard and the D-Link DIR-450, which OpenWrt now classifies as an aging target. Recent kernel touches to the code are only treewide cleanups rather than real hardware development, so unless someone surfaces an active user base it is reasonable to plan its eventual retirement.
repository signals
sources
- lore.kernel.org
Recent upstream touches exist, but the 2025 hit affecting r6040.c is a broad net-next API/assertion sweep, not evidence of active device-specific development.
- lore.kernel.org
Another recent touch is a small cross-driver DMA-mask cleanup, again suggesting maintenance-by-treewide-churn rather than active hardware evolution.
- cateee.net
LKDDb identifies this driver as support for the RDC R6040 MAC in RDC R-321x SoCs, tied to PCI ID 17f3:6040.
- openwrt.org
OpenWrt documents RDC as an old target for legacy boards such as Bifferboard, DIR-450, and evaluation boards, indicating residual embedded/router use rather than current mainstream deployment.
codex reasoning notes (technical)
Kconfig/source inspection via shell (`rg`, `sed`) shows this is the `r6040` PCI MAC driver for RDC R-321x SoCs. Lore evidence came from `lore_file_timeline`: it shows touches through 2024-2025, but the cited lore URLs are treewide or janitorial changes, and I found no concrete removal thread. Deployment evidence came from web search results: LKDDb confirms the exact hardware binding; OpenWrt's RDC target page points to aging router/embedded boards and legacy status. I infer the hardware is no longer sold new in 2025 and survives only in small legacy embedded deployments, so `deprecate` fits better than `remove`.