#ifndef DMA_COHERENT_H
  #define DMA_COHERENT_H
  
  #ifdef CONFIG_HAVE_GENERIC_DMA_COHERENT
  /*
   * These two functions are only for dma allocator.
   * Don't use them in device drivers.
   */
  int dma_alloc_from_coherent(struct device *dev, ssize_t size,
  				       dma_addr_t *dma_handle, void **ret);
  int dma_release_from_coherent(struct device *dev, int order, void *vaddr);
  
  /*
   * Standard interface
   */
  #define ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY
  extern int
  dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
  			    dma_addr_t device_addr, size_t size, int flags);
  
  extern void
  dma_release_declared_memory(struct device *dev);
  
  extern void *
  dma_mark_declared_memory_occupied(struct device *dev,
  				  dma_addr_t device_addr, size_t size);
  #else
  #define dma_alloc_from_coherent(dev, size, handle, ret) (0)
  #define dma_release_from_coherent(dev, order, vaddr) (0)
  #endif
  
  #endif