aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/include/asm/dma.h
blob: 9f2c5305c26014a9aea95faaf73a9c82c1260201 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
#ifndef __ASM_ARM_DMA_H
#define __ASM_ARM_DMA_H

typedef unsigned int dmach_t;

#include <linux/spinlock.h>
#include <asm/system.h>
#include <asm/scatterlist.h>
#include <asm/arch/dma.h>

/*
 * This is the maximum virtual address which can be DMA'd from.
 */
#ifndef MAX_DMA_ADDRESS
#define MAX_DMA_ADDRESS	0xffffffff
#endif

/*
 * DMA modes
 */
typedef unsigned int dmamode_t;

#define DMA_MODE_MASK	3

#define DMA_MODE_READ	 0
#define DMA_MODE_WRITE	 1
#define DMA_MODE_CASCADE 2
#define DMA_AUTOINIT	 4

extern spinlock_t  dma_spin_lock;

static inline unsigned long claim_dma_lock(void)
{
	unsigned long flags;
	spin_lock_irqsave(&dma_spin_lock, flags);
	return flags;
}

static inline void release_dma_lock(unsigned long flags)
{
	spin_unlock_irqrestore(&dma_spin_lock, flags);
}

/* Clear the 'DMA Pointer Flip Flop'.
 * Write 0 for LSB/MSB, 1 for MSB/LSB access.
 */
#define clear_dma_ff(channel)

/* Set only the page register bits of the transfer address.
 *
 * NOTE: This is an architecture specific function, and should
 *       be hidden from the drivers
 */
extern void set_dma_page(dmach_t channel, char pagenr);

/* Request a DMA channel
 *
 * Some architectures may need to do allocate an interrupt
 */
extern int  request_dma(dmach_t channel, const char * device_id);

/* Free a DMA channel
 *
 * Some architectures may need to do free an interrupt
 */
extern void free_dma(dmach_t channel);

/* Enable DMA for this channel
 *
 * On some architectures, this may have other side effects like
 * enabling an interrupt and setting the DMA registers.
 */
extern void enable_dma(dmach_t channel);

/* Disable DMA for this channel
 *
 * On some architectures, this may have other side effects like
 * disabling an interrupt or whatever.
 */
extern void disable_dma(dmach_t channel);

/* Test whether the specified channel has an active DMA transfer
 */
extern int dma_channel_active(dmach_t channel);

/* Set the DMA scatter gather list for this channel
 *
 * This should not be called if a DMA channel is enabled,
 * especially since some DMA architectures don't update the
 * DMA address immediately, but defer it to the enable_dma().
 */
extern void set_dma_sg(dmach_t channel, struct scatterlist *sg, int nr_sg);

/* Set the DMA address for this channel
 *
 * This should not be called if a DMA channel is enabled,
 * especially since some DMA architectures don't update the
 * DMA address immediately, but defer it to the enable_dma().
 */
extern void __set_dma_addr(dmach_t channel, void *addr);
#define set_dma_addr(channel, addr)				\
	__set_dma_addr(channel, bus_to_virt(addr))

/* Set the DMA byte count for this channel
 *
 * This should not be called if a DMA channel is enabled,
 * especially since some DMA architectures don't update the
 * DMA count immediately, but defer it to the enable_dma().
 */
extern void set_dma_count(dmach_t channel, unsigned long count);

/* Set the transfer direction for this channel
 *
 * This should not be called if a DMA channel is enabled,
 * especially since some DMA architectures don't update the
 * DMA transfer direction immediately, but defer it to the
 * enable_dma().
 */
extern void set_dma_mode(dmach_t channel, dmamode_t mode);

/* Set the transfer speed for this channel
 */
extern void set_dma_speed(dmach_t channel, int cycle_ns);

/* Get DMA residue count. After a DMA transfer, this
 * should return zero. Reading this while a DMA transfer is
 * still in progress will return unpredictable results.
 * If called before the channel has been used, it may return 1.
 * Otherwise, it returns the number of _bytes_ left to transfer.
 */
extern int  get_dma_residue(dmach_t channel);

#ifndef NO_DMA
#define NO_DMA	255
#endif

#ifdef CONFIG_PCI
extern int isa_dma_bridge_buggy;
#else
#define isa_dma_bridge_buggy    (0)
#endif

#endif /* _ARM_DMA_H */