Man page 9 : dma_mmap_from_coherent

dma_mmap_from_coherent - try to mmap the memory allocated from per-device coherent memory pool to userspace

int dma_mmap_from_coherent(struct device *  dev , struct vm_area_struct *  vma , void *  vaddr , size_t  size , int *  ret );

dev
    device from which the memory was allocated

vma
    vm_area for the userspace memory

vaddr
    cpu address returned by dma_alloc_from_coherent

size
    size of the memory buffer allocated by dma_alloc_from_coherent

ret
    result from remap_pfn_range

This checks whether the memory was allocated from the per-device coherent memory pool and if so, maps that memory to the provided vma.

Returns 1 if we correctly mapped the memory, or 0 if the caller should proceed with mapping memory from generic pools.