dmablib.h

来自「基于SAA7113的MPEG-4程序」· C头文件 代码 · 共 69 行

/*****************************************************************************

File		dmablib
Author		Sasi
Function	Library support for direct memory access & allocation for DMA 
		for Linux user mode clients
		Requires dmab.o driver to be loaded

*****************************************************************************/

#ifndef DMABLIB_SASI
#define DMABLIB_SASI


/* treat as opaque */
typedef struct
{
	unsigned long	size;	/* in - size to allocate */
	unsigned long	phys;	/* out - physical address allocated */
	void		*virt;	/* rsv - kernel virtual address mapped */
	void		*user;	/* out  - user virtual address mapped */
}
DMABUF_T;


int	dmab_init(char *name, int cache_on);
/*
	in	name	name of device file or NULL for default
	ret	-1 on failure
*/

int	dmab_exit(int h);
/*
	in	h	return from previous call to dmab_init
	ret	0 on failure
*/

void  *dmab_get(int fd, int size, DMABUF_T *t);
/*
	in	h	return from previous call to dmab_init
		size	bytes to allocate
	out	t	opaque structure for use in dmab_free
	proc	allocates & maps DMA buffer
	ret	t->user (0 on failure)
*/

int	dmab_free(int h, DMABUF_T *t);
/*
	in	h	return from previous call to dmab_init
		t	from previous successful call to dmab_get
	proc	unmaps buffer & frees it
	ret	0 on success
*/

int dmab_clean(int h, DMABUF_T *t);
/*
	flush data from cache to physical memory
*/

int dmab_invalidate(int h, DMABUF_T *t);
/*
	mark cache as invalid
	tell ARM to do subsequent read from physical memory 
*/


#endif