extern dma_addr_t swiotlb_map_single(struct device *hwdev, void *ptr,
size_t size, int dir);
extern void *swiotlb_alloc_coherent(struct device *hwdev, size_t size,
extern dma_addr_t swiotlb_map_single(struct device *hwdev, void *ptr,
size_t size, int dir);
extern void *swiotlb_alloc_coherent(struct device *hwdev, size_t size,