include/linux/comedi/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
  12 struct comedi_device;
  13 struct 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  */
  31 struct 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  */
  49 struct 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
  60 void comedi_isadma_program(struct comedi_isadma_desc *desc);
  61 unsigned int comedi_isadma_disable(unsigned int dma_chan);
  62 unsigned int comedi_isadma_disable_on_sample(unsigned int dma_chan,
  63                                              unsigned int size);
  64 unsigned int comedi_isadma_poll(struct comedi_isadma *dma);
  65 void comedi_isadma_set_mode(struct comedi_isadma_desc *desc, char dma_dir);
  66
  67 struct 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);
  71 void comedi_isadma_free(struct comedi_isadma *dma);
  72
  73 #else   /* !IS_ENABLED(CONFIG_ISA_DMA_API) */
  74
  75 static inline void comedi_isadma_program(struct comedi_isadma_desc *desc)
  76 {
  77 }
  78
  79 static inline unsigned int comedi_isadma_disable(unsigned int dma_chan)
  80 {
  81         return 0;
  82 }
  83
  84 static inline unsigned int
  85 comedi_isadma_disable_on_sample(unsigned int dma_chan, unsigned int size)
  86 {
  87         return 0;
  88 }
  89
  90 static inline unsigned int comedi_isadma_poll(struct comedi_isadma *dma)
  91 {
  92         return 0;
  93 }
  94
  95 static inline void comedi_isadma_set_mode(struct comedi_isadma_desc *desc,
  96                                           char dma_dir)
  97 {
  98 }
  99
 100 static inline struct comedi_isadma *
 101 comedi_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
 108 static 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 */