dma-mapping.h

来自「linux 内核源代码」· C头文件 代码 · 共 185 行

#ifndef _ASM_DMA_MAPPING_H
#define _ASM_DMA_MAPPING_H

#include <linux/device.h>
#include <asm/cache.h>
#include <asm/cacheflush.h>
#include <asm/scatterlist.h>
#include <asm/io.h>

#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)

extern unsigned long __nongprelbss dma_coherent_mem_start;
extern unsigned long __nongprelbss dma_coherent_mem_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);

/*
 * These macros should be used after a pci_map_sg call has been done
 * to get bus addresses of each of the SG entries and their lengths.
 * You should only work with the number of sg entries pci_map_sg
 * returns, or alternatively stop on the first sg_dma_len(sg) which
 * is 0.
 */
#define sg_dma_address(sg)	((sg)->dma_address)
#define sg_dma_len(sg)		((sg)->length)

/*
 * 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.
 */
static inline
void dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
		      enum dma_data_direction direction)
{
	BUG_ON(direction == DMA_NONE);
}

/*
 * 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.
 */
static inline
void dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nhwentries,
	     enum dma_data_direction direction)
{
	BUG_ON(direction == DMA_NONE);
}

extern
dma_addr_t dma_map_page(struct device *dev, struct page *page, unsigned long offset,
			size_t size, enum dma_data_direction direction);

static inline
void dma_unmap_page(struct device *dev, dma_addr_t dma_address, size_t size,
		    enum dma_data_direction direction)
{
	BUG_ON(direction == DMA_NONE);
}


static inline
void dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, size_t size,
			     enum dma_data_direction direction)
{
}

static inline
void dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle, size_t size,
				enum dma_data_direction direction)
{
	flush_write_buffers();
}

static inline
void dma_sync_single_range_for_cpu(struct device *dev, dma_addr_t dma_handle,
				   unsigned long offset, size_t size,
				   enum dma_data_direction direction)
{
}

static inline
void dma_sync_single_range_for_device(struct device *dev, dma_addr_t dma_handle,
				      unsigned long offset, size_t size,
				      enum dma_data_direction direction)
{
	flush_write_buffers();
}

static inline
void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nelems,
			 enum dma_data_direction direction)
{
}

static inline
void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nelems,
			    enum dma_data_direction direction)
{
	flush_write_buffers();
}

static inline
int dma_mapping_error(dma_addr_t dma_addr)
{
	return 0;
}

static inline
int dma_supported(struct device *dev, u64 mask)
{
        /*
         * we fall back to GFP_DMA when the mask isn't all 1s,
         * so we can't guarantee allocations that must be
         * within a tighter range than GFP_DMA..
         */
        if (mask < 0x00ffffff)
                return 0;

	return 1;
}

static inline
int dma_set_mask(struct device *dev, u64 mask)
{
	if (!dev->dma_mask || !dma_supported(dev, mask))
		return -EIO;

	*dev->dma_mask = mask;

	return 0;
}

static inline
int dma_get_cache_alignment(void)
{
	return 1 << L1_CACHE_SHIFT;
}

#define dma_is_consistent(d, h)	(1)

static inline
void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
		    enum dma_data_direction direction)
{
	flush_write_buffers();
}

#endif  /* _ASM_DMA_MAPPING_H */