Contents
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;