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How to configure the Linux kernel/arch/sh/drivers/dma

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Howto configure the Linux kernel / arch / sh / drivers / dma


DMA supportEdit

  • Option: SH_DMA
    • Kernel Versions: 2.6.15.6 ...
    • (on/off) DMA controller (DMAC) support
      Selecting this option will provide same API as PC's Direct Memory Access Controller(8237A) for SuperH DMAC.
      If unsure, say N.


  • Option: NR_ONCHIP_DMA_CHANNELS
    • Kernel Versions: 2.6.15.6 ...
    • depends on SH_DMA

"Number of on-chip DMAC channels"

    • default "4"
      This allows you to specify the number of channels that the on-chip DMAC supports. This will be 4 for SH7750/SH7751 and 8 for the SH7750R/SH7751R.


  • Option: NR_DMA_CHANNELS_BOOL
    • Kernel Versions: 2.6.15.6 ...
    • depends on SH_DMA
    • (on/off) Override default number of maximum DMA channels
      This allows you to forcibly update the maximum number of supported DMA channels for a given board. If this is unset, this will default to the number of channels that the on-chip DMAC has.


  • Option: NR_DMA_CHANNELS
    • Kernel Versions: 2.6.15.6 ...

"Maximum number of DMA channels"

    • depends on SH_DMA && NR_DMA_CHANNELS_BOOL
    • default NR_ONCHIP_DMA_CHANNELS
      This allows you to specify the maximum number of DMA channels to support. Setting this to a higher value allows for cascading DMACs with additional channels.


  • Option: DMA_PAGE_OPS
    • Kernel Versions: 2.6.15.6 ...
    • (on/off) Use DMAC for page copy/clear
    • depends on SH_DMA && BROKEN
      Selecting this option will use a dual-address mode configured channel in the SH DMAC for copy_page()/clear_page(). Primarily a performance hack.


  • Option: DMA_PAGE_OPS_CHANNEL
    • Kernel Versions: 2.6.15.6 ...
    • depends on DMA_PAGE_OPS

"DMA channel for sh memory-manager page copy/clear"

    • default "3"
      This allows the specification of the dual address dma channel, in case channel 3 is unavailable. On the SH4, channels 1,2, and 3 are dual-address capable.



Linux Kernel Configuration

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