Memory-mapped NOR flash and ROM chip maps (physmap and legacy boards)
A collection of drivers that expose NOR flash, ROM, and battery-backed RAM chips wired directly into a CPU's memory bus, so the kernel can read and write them as MTD storage. The generic physmap and plat-ram paths are still widely used on embedded and industrial boards shipping today, while many of the per-board files cover specific 1990s–2000s reference designs and PC add-in cards.
recommendation
Worth keeping but documenting the split: the generic physmap-core code is actively maintained, with 2023–2025 fixes including support for flash larger than 4 GB and a late-2025 pcmciamtd leak fix, and modern device-tree-based embedded systems still rely on it. Many of the older per-board map files, however, are legacy dead weight; one such leaf (the Intel Carillo Ranch/intel_vr_nor map for hardware that may never have shipped) was already pruned in 2024, and similar selective removals are likely to continue.
repository signals
sources
- cateee.net
CONFIG_MTD_PHYSMAP is still present in current kernels, with physmap-core DT/platform matches listed through 6.19/7.0, indicating ongoing in-tree applicability rather than abandonment.
- patchwork.ozlabs.org
physmap-core received accepted upstream maintenance work in 2023, showing active subsystem attention to the core map driver path.
- spinics.net
A 2024 thread confirms removal of one dead subdriver (intel_vr_nor / Carillo Ranch) because the product likely never shipped, showing selective pruning of obsolete leaf drivers rather than removal of the whole maps directory.
- spinics.net
drivers/mtd/maps still received a real bug-fix patch in late 2025 (pcmciamtd leak fix), evidence of current maintenance traffic.
- patchew.org
physmap-core had a 2024 upstream/stable fix for >32-bit flash size handling, which points to real current users of the generic direct-mapped path on modern 64-bit systems.
codex reasoning notes (technical)
Local shell inspection of Kconfig and source markers shows this is a real driver directory centered on generic physmap plus many legacy board maps. Local git log (shell, with safe.directory override) showed substantial 2021-2026 activity, including recent physmap-core and pcmciamtd work, and only one actual removal of a dead leaf driver. URLs were obtained via web search/open for LKDDb, Patchwork, spinics, and Patchew. Conclusion: keep the directory, but annotate that many per-board map drivers are legacy while generic physmap/plat-ram paths remain relevant for embedded/industrial memory-mapped flash and ROM deployments.