MediaTek SoC DMA controllers (APDMA, CQDMA, HSDMA)
On-chip DMA engines built into MediaTek system-on-chip processors, used to move data between memory and peripherals such as UARTs without tying up the CPU. They appear in everything from MT7622 Wi-Fi router SoCs to recent Dimensity-class smartphone and embedded chips like the MT6985 and MT6835.
recommendation
It should stay in the kernel because MediaTek is still shipping new SoCs that rely on these DMA blocks, and the code covers a span of chips from older router platforms through 2023-era flagship mobile parts. Upstream maintenance is clearly ongoing, with fixes still being backported to stable kernels as recently as 2026, and there is no generic replacement that could take over the job.
repository signals
sources
- lore.kernel.org
`mtk-uart-apdma.c` was still being backported into stable trees in March 2026, which is evidence of ongoing upstream maintenance rather than abandonment.
- mediatek.com
MT7622, one of the SoCs supported by this driver family, was positioned for routers, repeaters, whole-home Wi-Fi, and home-automation gateways.
- mediatek.com
MediaTek was still actively marketing current flagship smartphone SoCs in this broader mobile SoC family, supporting the view that related on-SoC DMA IP remains relevant in new hardware.
- cpubenchmark.net
MT6985, which matches a compatible string present in this directory, is identified as a 2023 mobile/embedded SoC and still had fresh benchmark activity in 2026, suggesting ongoing field deployment.
codex reasoning notes (technical)
Local `rg` inspection showed three real platform DMA drivers here (`mtk-hsdma`, `mtk-cqdma`, `mtk-uart-apdma`) with compatibles ranging from older MT7622/MT6765 to newer MT6985/MT6835, so this is an active MediaTek SoC DMA block family with no generic replacement driver. Lore evidence was obtained via `lore_activity` and `lore_file_timeline` on `drivers/dma/mediatek/mtk-uart-apdma.c`; the cited lore URL shows 2026 stable backport activity. Web evidence was obtained via `web.search_query`; the MediaTek URLs support continuing product-family relevance and the MT7622 deployment niche, while the MT6985 benchmark page supports current deployments. No removal discussion surfaced in the limited lore sample, so `keep` is the defensible recommendation.