dma-mapping.h

来自「linux 内核源代码」· C头文件 代码 · 共 69 行

#ifndef _BLACKFIN_DMA_MAPPING_H
#define _BLACKFIN_DMA_MAPPING_H

#include <asm/scatterlist.h>

void dma_alloc_init(unsigned long start, unsigned long end);
void *dma_alloc_coherent(struct device *dev, size_t size,
			 dma_addr_t *dma_handle, gfp_t gfp);
void dma_free_coherent(struct device *dev, size_t size, void *vaddr,
		       dma_addr_t dma_handle);

/*
 * Now for the API extensions over the pci_ one
 */
#define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)
#define dma_free_noncoherent(d, s, v, h) dma_free_coherent(d, s, v, h)

#define dma_mapping_error

/*
 * Map a single buffer of the indicated size for DMA in streaming mode.
 * The 32-bit bus address to use is returned.
 *
 * Once the device is given the dma address, the device owns this memory
 * until either pci_unmap_single or pci_dma_sync_single is performed.
 */
extern dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
				 enum dma_data_direction direction);

/*
 * Unmap a single streaming mode DMA translation.  The dma_addr and size
 * must match what was provided for in a previous pci_map_single call.  All
 * other usages are undefined.
 *
 * After this call, reads by the cpu to the buffer are guarenteed to see
 * whatever the device wrote there.
 */
extern void dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
			  enum dma_data_direction direction);

/*
 * Map a set of buffers described by scatterlist in streaming
 * mode for DMA.  This is the scather-gather version of the
 * above pci_map_single interface.  Here the scatter gather list
 * elements are each tagged with the appropriate dma address
 * and length.  They are obtained via sg_dma_{address,length}(SG).
 *
 * NOTE: An implementation may be able to use a smaller number of
 *       DMA address/length pairs than there are SG table elements.
 *       (for example via virtual mapping capabilities)
 *       The routine returns the number of addr/length pairs actually
 *       used, at most nents.
 *
 * Device ownership issues as mentioned above for pci_map_single are
 * the same here.
 */
extern int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
		      enum dma_data_direction direction);

/*
 * Unmap a set of streaming mode DMA translations.
 * Again, cpu read rules concerning calls here are the same as for
 * pci_unmap_single() above.
 */
extern void dma_unmap_sg(struct device *dev, struct scatterlist *sg,
		      int nhwentries, enum dma_data_direction direction);

#endif				/* _BLACKFIN_DMA_MAPPING_H */