1. 根目录:
2. arch
3. cris
4. include
5. asm
6. dma-mapping.h

/* DMA mapping. Nothing tricky here, just virt_to_phys */

#ifndef _ASM_CRIS_DMA_MAPPING_H
#define _ASM_CRIS_DMA_MAPPING_H

#include <linux/mm.h>
#include <linux/kernel.h>

#include <asm/cache.h>
#include <asm/io.h>
#include <asm/scatterlist.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)

#ifdef CONFIG_PCI
#include <asm-generic/dma-coherent.h>

void *dma_alloc_coherent(struct device *dev, size_t size,
			   dma_addr_t *dma_handle, gfp_t flag);

void dma_free_coherent(struct device *dev, size_t size,
			 void *vaddr, dma_addr_t dma_handle);
#else
static inline void *
dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
                   gfp_t flag)
{
        BUG();
        return NULL;
}

static inline void
dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
                    dma_addr_t dma_handle)
{
        BUG();
}
#endif
static inline dma_addr_t
dma_map_single(struct device *dev, void *ptr, size_t size,
	       enum dma_data_direction direction)
{
	BUG_ON(direction == DMA_NONE);
	return virt_to_phys(ptr);
}

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);
}

static inline int
dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
	   enum dma_data_direction direction)
{
	printk("Map sg\n");
	return nents;
}

static inline dma_addr_t
dma_map_page(struct device *dev, struct page *page, unsigned long offset,
	     size_t size, enum dma_data_direction direction)
{
	BUG_ON(direction == DMA_NONE);
	return page_to_phys(page) + offset;
}

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_unmap_sg(struct device *dev, struct scatterlist *sg, int nhwentries,
	     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)
{
}

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)
{
}

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)
{
}

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

/* drivers/base/dma-mapping.c */
extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
			   void *cpu_addr, dma_addr_t dma_addr, size_t size);
extern int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
				  void *cpu_addr, dma_addr_t dma_addr,
				  size_t size);

#define dma_mmap_coherent(d, v, c, h, s) dma_common_mmap(d, v, c, h, s)
#define dma_get_sgtable(d, t, v, h, s) dma_common_get_sgtable(d, t, v, h, s)


#endif