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 
comedi_isadma_program(struct comedi_isadma_desc * desc)75 static inline void comedi_isadma_program(struct comedi_isadma_desc *desc)
76 {
77 }
78 
comedi_isadma_disable(unsigned int dma_chan)79 static inline unsigned int comedi_isadma_disable(unsigned int dma_chan)
80 {
81 	return 0;
82 }
83 
84 static inline unsigned int
comedi_isadma_disable_on_sample(unsigned int dma_chan,unsigned int size)85 comedi_isadma_disable_on_sample(unsigned int dma_chan, unsigned int size)
86 {
87 	return 0;
88 }
89 
comedi_isadma_poll(struct comedi_isadma * dma)90 static inline unsigned int comedi_isadma_poll(struct comedi_isadma *dma)
91 {
92 	return 0;
93 }
94 
comedi_isadma_set_mode(struct comedi_isadma_desc * desc,char dma_dir)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 *
comedi_isadma_alloc(struct comedi_device * dev,int n_desc,unsigned int dma_chan1,unsigned int dma_chan2,unsigned int maxsize,char dma_dir)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 
comedi_isadma_free(struct comedi_isadma * dma)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 */
115