comedi_isadma.h

  1/* SPDX-License-Identifier: GPL-2.0+ */
  2/*
  3 * COMEDI ISA DMA support functions
  4 * Copyright (c) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
  5 */
  6
  7#ifndef _COMEDI_ISADMA_H
  8#define _COMEDI_ISADMA_H
  9
 10#include <linux/types.h>
 11
 12struct comedi_device;
 13struct device;
 14
 15/*
 16 * These are used to avoid issues when <asm/dma.h> and the DMA_MODE_
 17 * defines are not available.
 18 */
 19#define COMEDI_ISADMA_READ	0
 20#define COMEDI_ISADMA_WRITE	1
 21
 22/**
 23 * struct comedi_isadma_desc - cookie for ISA DMA
 24 * @virt_addr:	virtual address of buffer
 25 * @hw_addr:	hardware (bus) address of buffer
 26 * @chan:	DMA channel
 27 * @maxsize:	allocated size of buffer (in bytes)
 28 * @size:	transfer size (in bytes)
 29 * @mode:	DMA_MODE_READ or DMA_MODE_WRITE
 30 */
 31struct comedi_isadma_desc {
 32	void *virt_addr;
 33	dma_addr_t hw_addr;
 34	unsigned int chan;
 35	unsigned int maxsize;
 36	unsigned int size;
 37	char mode;
 38};
 39
 40/**
 41 * struct comedi_isadma - ISA DMA data
 42 * @dev:	device to allocate non-coherent memory for
 43 * @desc:	cookie for each DMA buffer
 44 * @n_desc:	the number of cookies
 45 * @cur_dma:	the current cookie in use
 46 * @chan:	the first DMA channel requested
 47 * @chan2:	the second DMA channel requested
 48 */
 49struct comedi_isadma {
 50	struct device *dev;
 51	struct comedi_isadma_desc *desc;
 52	int n_desc;
 53	int cur_dma;
 54	unsigned int chan;
 55	unsigned int chan2;
 56};
 57
 58#if IS_ENABLED(CONFIG_ISA_DMA_API)
 59
 60void comedi_isadma_program(struct comedi_isadma_desc *desc);
 61unsigned int comedi_isadma_disable(unsigned int dma_chan);
 62unsigned int comedi_isadma_disable_on_sample(unsigned int dma_chan,
 63					     unsigned int size);
 64unsigned int comedi_isadma_poll(struct comedi_isadma *dma);
 65void comedi_isadma_set_mode(struct comedi_isadma_desc *desc, char dma_dir);
 66
 67struct comedi_isadma *comedi_isadma_alloc(struct comedi_device *dev,
 68					  int n_desc, unsigned int dma_chan1,
 69					  unsigned int dma_chan2,
 70					  unsigned int maxsize, char dma_dir);
 71void comedi_isadma_free(struct comedi_isadma *dma);
 72
 73#else	/* !IS_ENABLED(CONFIG_ISA_DMA_API) */
 74
 75static inline void comedi_isadma_program(struct comedi_isadma_desc *desc)
 76{
 77}
 78
 79static inline unsigned int comedi_isadma_disable(unsigned int dma_chan)
 80{
 81	return 0;
 82}
 83
 84static inline unsigned int
 85comedi_isadma_disable_on_sample(unsigned int dma_chan, unsigned int size)
 86{
 87	return 0;
 88}
 89
 90static inline unsigned int comedi_isadma_poll(struct comedi_isadma *dma)
 91{
 92	return 0;
 93}
 94
 95static inline void comedi_isadma_set_mode(struct comedi_isadma_desc *desc,
 96					  char dma_dir)
 97{
 98}
 99
100static inline struct comedi_isadma *
101comedi_isadma_alloc(struct comedi_device *dev, int n_desc,
102		    unsigned int dma_chan1, unsigned int dma_chan2,
103		    unsigned int maxsize, char dma_dir)
104{
105	return NULL;
106}
107
108static inline void comedi_isadma_free(struct comedi_isadma *dma)
109{
110}
111
112#endif	/* !IS_ENABLED(CONFIG_ISA_DMA_API) */
113
114#endif	/* #ifndef _COMEDI_ISADMA_H */