User:ZyMOS/Howto configure the linux kernel/arch/sh/drivers/dma

User:ZyMOS/Howto configure the linux kernel / arch / sh / drivers / dma

DMA support

 * 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.

"Number of on-chip DMAC channels"
 * Option: NR_ONCHIP_DMA_CHANNELS
 * Kernel Versions: 2.6.15.6 ...
 * depends on SH_DMA
 * 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.

"Maximum number of DMA channels"
 * Option: NR_DMA_CHANNELS
 * Kernel Versions: 2.6.15.6 ...
 * 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.

"DMA channel for sh memory-manager page copy/clear"
 * Option: DMA_PAGE_OPS_CHANNEL
 * Kernel Versions: 2.6.15.6 ...
 * depends on DMA_PAGE_OPS
 * 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.