scatterlist.h

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

/*
 * BK Id: SCCS/s.scatterlist.h 1.9 10/15/01 22:51:33 paulus
 */
#ifdef __KERNEL__
#ifndef _PPC_SCATTERLIST_H
#define _PPC_SCATTERLIST_H

#include <asm/dma.h>

struct scatterlist {
	char *address;		/* Location data is to be transferred to,
				 * or NULL for highmem page */
	struct page * page;	/* Location for highmem page, if any */
	unsigned int offset;	/* for highmem, page offset */

	dma_addr_t dma_address;	/* phys/bus dma address		 */
	unsigned int length;	/* length			 */
};

/*
 * 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)

#endif /* !(_PPC_SCATTERLIST_H) */
#endif /* __KERNEL__ */