Arm CoreLink SMMUv1/v2 and MMU-500 IOMMU
The I/O memory management unit found in a large swath of Arm-based SoCs from roughly the early 2010s onward, including Qualcomm and NVIDIA platforms. It translates and isolates DMA from on-chip devices on behalf of the OS, and covers Arm's SMMU architecture versions 1 and 2 as well as the widely licensed CoreLink MMU-500 IP block.
recommendation
It should stay because the hardware is still in active use and Arm continues to license and teach the underlying IP. Patches were still landing on linux-iommu in early 2026, including stable backports and adjustments for driver-core changes, and Arm's 2025 Flexible Access catalog and 2026 training materials still feature MMU-500 and SMMUv2 alongside newer parts. The newer arm-smmu-v3 driver is a different architecture and is not a drop-in replacement for the existing installed base.
repository signals
sources
- lore.kernel.org
As of 2026-03-13 the driver still receives functional fixes on linux-iommu, indicating active upstream maintenance rather than retirement.
- lore.kernel.org
As of 2026-01-21 arm-smmu subcomponents were still being fixed and adjusted for driver-core changes, showing current integration work.
- developer.arm.com
Arm's 2026 System MMU training material still covers SMMUv2/MMU-500 alongside newer MMU-600/MMU-700 parts, evidence that the IP family remains relevant in current SoC work.
- developer.arm.com
Arm Flexible Access material published in 2025 still lists CoreLink MMU-500 as an available IP block, supporting that related hardware/IP was still being offered in 2025.
codex reasoning notes (technical)
Real driver directory. Local source inspection showed Kconfig entry 'ARM Ltd. System MMU (SMMU) Support' for SMMU architecture v1/v2 and Qualcomm/NVIDIA implementation files. lore_file_timeline and lore_activity on arm-smmu.c showed heavy multi-year traffic through 2026, including bug-fix patches and stable backports; no removal signal surfaced in the timeline. A broader removal-subject lore_regex query timed out and sandboxed lei could not start, so the recommendation relies on strong positive maintenance evidence rather than exhaustive negative proof. Arm web search results supplied the 2026 SMMU training PDF and 2025 Flexible Access datasheet showing MMU-500/SMMUv2 still marketed/taught, so this is not obsolete legacy-only hardware. No natural upstream replacement exists for the same installed base; arm-smmu-v3 is a different architecture generation, not a drop-in replacement for v1/v2 deployments.