Linux DMA

DMA Controller/Engine

source code

• include/linux/dmaengine.h

• drivers/dma/dmaengine.c

• include/linux/amba/pl330.h

• drivers/dma/pl330.c

document

• (maxime, 2015) An Overview of the DMAEngine Subsystem

• Documentation/dmaengine/client.txt

• Documentation/dmaengine/provider.txt

• ARM PL330 DMA Controller Manual

• 详解 ARM 的 AMBA 设备中的 DMA 设备 PL08X 的 Linux 驱动: http://www.crifan.com/files/doc/docbook/dma_pl08x_analysis/release/htmls/index.html

DMA Mapping

source code

• include/linux/dma-mapping.h

• arch/arm/mm/dma-mapping.c: implement 4 type of dma_map_ops

more: DMA Mapping

document

• (Laurent, 2014) [ELC2014] Mastering the DMA and IOMMU API

• LDD3 ch15 Memory Mapping and DMA

• Documentation/DMA-API-HOWTO.txt

• ( 2011) [lwn] ARM, DMA, and memory management

• (Marek, Kyungmin, 2011, Samsung) [ELC Europe] ARM DMA-Mapping Framework Redesign and IOMMU integration

  • Three different implementations merged together (arch/arm/mm/dma-mapping.c)

    • linear non-coherent (most systems)

    • linear coherent (noMMU and Intel ixp23xx)

    • ‘bounced’ for systems with restricted or limited/broken DMA engines

• ( 2014) ARM Dma-mapping Explained