Man page 9 : dma_alloc_from_coherent

dma_alloc_from_coherent - try to allocate memory from the per-device coherent area

int dma_alloc_from_coherent(struct device *  dev , ssize_t  size , dma_addr_t *  dma_handle , void **  ret );

dev
    device from which we allocate memory

size
    size of requested memory area

dma_handle
    This will be filled with the correct dma handle

ret
    This pointer will be filled with the virtual address to allocated area.

This function should be only called from per-arch dma_alloc_coherent to support allocation from per-device coherent memory pools.

Returns 0 if dma_alloc_coherent should continue with allocating from generic memory areas, or !0 if dma_alloc_coherent should return ret.