1. 根目录:
2. include
3. asm-generic
4. dma-mapping-common.h

#ifndef _ASM_GENERIC_DMA_MAPPING_H
#define _ASM_GENERIC_DMA_MAPPING_H

#include <linux/kmemcheck.h>
#include <linux/scatterlist.h>
#include <linux/dma-debug.h>
#include <linux/dma-attrs.h>

static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
					      size_t size,
					      enum dma_data_direction dir,
					      struct dma_attrs *attrs)
{
	struct dma_map_ops *ops = get_dma_ops(dev);
	dma_addr_t addr;

	kmemcheck_mark_initialized(ptr, size);
	BUG_ON(!valid_dma_direction(dir));
	addr = ops->map_page(dev, virt_to_page(ptr),
			     (unsigned long)ptr & ~PAGE_MASK, size,
			     dir, attrs);
	debug_dma_map_page(dev, virt_to_page(ptr),
			   (unsigned long)ptr & ~PAGE_MASK, size,
			   dir, addr, true);
	return addr;
}

static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
					  size_t size,
					  enum dma_data_direction dir,
					  struct dma_attrs *attrs)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	BUG_ON(!valid_dma_direction(dir));
	if (ops->unmap_page)
		ops->unmap_page(dev, addr, size, dir, attrs);
	debug_dma_unmap_page(dev, addr, size, dir, true);
}

static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
				   int nents, enum dma_data_direction dir,
				   struct dma_attrs *attrs)
{
	struct dma_map_ops *ops = get_dma_ops(dev);
	int i, ents;
	struct scatterlist *s;

	for_each_sg(sg, s, nents, i)
		kmemcheck_mark_initialized(sg_virt(s), s->length);
	BUG_ON(!valid_dma_direction(dir));
	ents = ops->map_sg(dev, sg, nents, dir, attrs);
	debug_dma_map_sg(dev, sg, nents, ents, dir);

	return ents;
}

static inline void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
				      int nents, enum dma_data_direction dir,
				      struct dma_attrs *attrs)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	BUG_ON(!valid_dma_direction(dir));
	debug_dma_unmap_sg(dev, sg, nents, dir);
	if (ops->unmap_sg)
		ops->unmap_sg(dev, sg, nents, dir, attrs);
}

static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
				      size_t offset, size_t size,
				      enum dma_data_direction dir)
{
	struct dma_map_ops *ops = get_dma_ops(dev);
	dma_addr_t addr;

	kmemcheck_mark_initialized(page_address(page) + offset, size);
	BUG_ON(!valid_dma_direction(dir));
	addr = ops->map_page(dev, page, offset, size, dir, NULL);
	debug_dma_map_page(dev, page, offset, size, dir, addr, false);

	return addr;
}

static inline void dma_unmap_page(struct device *dev, dma_addr_t addr,
				  size_t size, enum dma_data_direction dir)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	BUG_ON(!valid_dma_direction(dir));
	if (ops->unmap_page)
		ops->unmap_page(dev, addr, size, dir, NULL);
	debug_dma_unmap_page(dev, addr, size, dir, false);
}

static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
					   size_t size,
					   enum dma_data_direction dir)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	BUG_ON(!valid_dma_direction(dir));
	if (ops->sync_single_for_cpu)
		ops->sync_single_for_cpu(dev, addr, size, dir);
	debug_dma_sync_single_for_cpu(dev, addr, size, dir);
}

static inline void dma_sync_single_for_device(struct device *dev,
					      dma_addr_t addr, size_t size,
					      enum dma_data_direction dir)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	BUG_ON(!valid_dma_direction(dir));
	if (ops->sync_single_for_device)
		ops->sync_single_for_device(dev, addr, size, dir);
	debug_dma_sync_single_for_device(dev, addr, size, dir);
}

static inline void dma_sync_single_range_for_cpu(struct device *dev,
						 dma_addr_t addr,
						 unsigned long offset,
						 size_t size,
						 enum dma_data_direction dir)
{
	dma_sync_single_for_cpu(dev, addr + offset, size, dir);
}

static inline void dma_sync_single_range_for_device(struct device *dev,
						    dma_addr_t addr,
						    unsigned long offset,
						    size_t size,
						    enum dma_data_direction dir)
{
	dma_sync_single_for_device(dev, addr + offset, size, dir);
}

static inline void
dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
		    int nelems, enum dma_data_direction dir)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	BUG_ON(!valid_dma_direction(dir));
	if (ops->sync_sg_for_cpu)
		ops->sync_sg_for_cpu(dev, sg, nelems, dir);
	debug_dma_sync_sg_for_cpu(dev, sg, nelems, dir);
}

static inline void
dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
		       int nelems, enum dma_data_direction dir)
{
	struct dma_map_ops *ops = get_dma_ops(dev);

	BUG_ON(!valid_dma_direction(dir));
	if (ops->sync_sg_for_device)
		ops->sync_sg_for_device(dev, sg, nelems, dir);
	debug_dma_sync_sg_for_device(dev, sg, nelems, dir);

}

#define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, NULL)
#define dma_unmap_single(d, a, s, r) dma_unmap_single_attrs(d, a, s, r, NULL)
#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, NULL)
#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, NULL)

#endif