NXP i.MX8 and i.MX9 system-controller firmware interfaces
Kernel-side glue for talking to the on-chip system controller firmware on NXP's i.MX8 and i.MX9 application processors, covering both the older SCU mailbox protocol used on i.MX8/i.MX8X and the newer SCMI-based interfaces on i.MX94 and i.MX95. These SoCs are widely used in industrial, automotive, and embedded designs sold today.
recommendation
It should stay because the underlying NXP i.MX8X and i.MX95 chips are current, actively-sold parts, and the code is still seeing real upstream development — including feature work on the SCMI side in early 2026 and maintenance on the older SCU path in late 2025. There is no replacement driver that supersedes it; the newer SCMI pieces sit alongside the SCU code rather than retiring it.
repository signals
sources
- lore.kernel.org
`sm-misc.c` saw a substantive feature patch in March 2026, indicating active upstream development rather than retirement.
- lore.kernel.org
`imx-scu.c` received maintenance changes in October 2025, showing the older SCU side is still being touched upstream.
- nxp.com
NXP lists the i.MX95 family as Active, supporting the conclusion that related i.MX firmware interfaces remain relevant for new designs.
- nxp.com
NXP lists the i.MX8X family as Active; this matches the directory's i.MX8 SCU/DSP support and indicates ongoing fielded and sellable hardware.
codex reasoning notes (technical)
Not an early-exit case: local shell inspection showed real driver code and Kconfig entries for i.MX8 SCU/DSP plus SCMI CPU/LMM/MISC, with DT compatibles including i.MX94/i.MX95. Lore evidence came from `lore_activity` and `lore_file_timeline`: both `sm-misc.c` and `imx-scu.c` have recent 2025-2026 feature/cleanup traffic and multi-author touches, with no removal pattern visible in the returned histories. A `lore_regex` removal-subject probe timed out, so I did not retry that same query. Deployment is best classified as medium: these are niche embedded/industrial/automotive SoC firmware interfaces, not mass-market PC hardware, but they map to still-active NXP i.MX8X and i.MX95 product families found via web search. No single replacement driver cleanly supersedes this directory across the supported SoCs; newer SCMI pieces complement rather than universally replace the older SCU path.