LXR linux/drivers/staging/comedi/drivers/comedi

   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 */
 115