linux/drivers/ieee1394/dma.h

/*
 * DMA region bookkeeping routines
 *
 * Copyright (C) 2002 Maas Digital LLC
 *
 * This code is licensed under the GPL.  See the file COPYING in the root
 * directory of the kernel sources for details.
 */

#ifndef IEEE1394_DMA_H
#define IEEE1394_DMA_H

#include <asm/types.h>

struct pci_dev;
struct scatterlist;
struct vm_area_struct;

/**
 * struct dma_prog_region - small contiguous DMA buffer
 * @kvirt:    kernel virtual address
 * @dev:      PCI device
 * @n_pages:  number of kernel pages
 * @bus_addr: base bus address
 *
 * a small, physically contiguous DMA buffer with random-access, synchronous
 * usage characteristics
 */
struct dma_prog_region {
	unsigned char *kvirt;
	struct pci_dev *dev;
	unsigned int n_pages;
	dma_addr_t bus_addr;
};

/* clear out all fields but do not allocate any memory */
void dma_prog_region_init(struct dma_prog_region *prog);
int dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes,
			  struct pci_dev *dev);
void dma_prog_region_free(struct dma_prog_region *prog);

static inline dma_addr_t dma_prog_region_offset_to_bus(
		struct dma_prog_region *prog, unsigned long offset)
{
	return prog->bus_addr + offset;
}

/**
 * struct dma_region - large non-contiguous DMA buffer
 * @virt:        kernel virtual address
 * @dev:         PCI device
 * @n_pages:     number of kernel pages
 * @n_dma_pages: number of IOMMU pages
 * @sglist:      IOMMU mapping
 * @direction:   PCI_DMA_TODEVICE, etc.
 *
 * a large, non-physically-contiguous DMA buffer with streaming, asynchronous
 * usage characteristics
 */
struct dma_region {
	unsigned char *kvirt;
	struct pci_dev *dev;
	unsigned int n_pages;
	unsigned int n_dma_pages;
	struct scatterlist *sglist;
	int direction;
};

/* clear out all fields but do not allocate anything */
void dma_region_init(struct dma_region *dma);

/* allocate the buffer and map it to the IOMMU */
int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
		     struct pci_dev *dev, int direction);

/* unmap and free the buffer */
void dma_region_free(struct dma_region *dma);

/* sync the CPU's view of the buffer */
void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
			     unsigned long len);

/* sync the IO bus' view of the buffer */
void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset,
				unsigned long len);

/* map the buffer into a user space process */
int  dma_region_mmap(struct dma_region *dma, struct file *file,
		     struct vm_area_struct *vma);

/* macro to index into a DMA region (or dma_prog_region) */
#define dma_region_i(_dma, _type, _index) \
	( ((_type*) ((_dma)->kvirt)) + (_index) )

/* return the DMA bus address of the byte with the given offset
 * relative to the beginning of the dma_region */
dma_addr_t dma_region_offset_to_bus(struct dma_region *dma,
				    unsigned long offset);

#endif /* IEEE1394_DMA_H */