DmaInfo

The structure describing the DMA buffer is declared in the io/io_dma.h file.

typedef struct {

/** DMA flags (attributes). */

DmaAttr flags;

/** Minimum order of DMA blocks in the buffer. */

rtl_size_t orderMin;

/** DMA buffer size. */

rtl_size_t size;

/** Number of DMA blocks (less than or equal to DMA_FRAMES_COUNT_MAX).

* It may be equal to 0 if a DMA buffer is not available for the device. */

rtl_size_t count;

/** Array of DMA block descriptors. */

union DmaFrameDescriptor {

struct {

/** Order of the DMA block. The number of pages in a block is equal to two

* to the power of the specified order. */

DmaAddr order: DMA_FRAME_ORDER_BITS;

/** Physical or IOMMU address of the DMA block. */

DmaAddr frame: DMA_FRAME_BASE_BITS;

};

/** DMA block descriptor */

DmaAddr raw;

} descriptors[1];

} DmaInfo;