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