The HBA driver must describe the attributes of its DMA engine by properly initializing the ddi_dma_attr_t structure.
static ddi_dma_attr_t isp_dma_attr = { DMA_ATTR_V0, /* ddi_dma_attr version */ 0, /* low address */ 0xffffffff, /* high address */ 0x00ffffff, /* counter upper bound */ 1, /* alignment requirements */ 0x3f, /* burst sizes */ 1, /* minimum DMA access */ 0xffffffff, /* maximum DMA access */ (1<<24)-1, /* segment boundary restrictions */ 1, /* scatter-gather list length */ 512, /* device granularity */ 0 /* DMA flags */ };
The driver, if providing DMA, should also check that its hardware is installed in a DMA-capable slot:
if (ddi_slaveonly(dip) == DDI_SUCCESS) { return (DDI_FAILURE); }