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
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
|
/*
* linux/arch/arm/kernel/dma.c
*
* Copyright (C) 1995-2000 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Front-end to the DMA handling. This handles the allocation/freeing
* of DMA channels, and provides a unified interface to the machines
* DMA facilities.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/scatterlist.h>
#include <asm/dma.h>
#include <asm/mach/dma.h>
DEFINE_SPINLOCK(dma_spin_lock);
EXPORT_SYMBOL(dma_spin_lock);
static dma_t *dma_chan[MAX_DMA_CHANNELS];
static inline dma_t *dma_channel(unsigned int chan)
{
if (chan >= MAX_DMA_CHANNELS)
return NULL;
return dma_chan[chan];
}
int __init isa_dma_add(unsigned int chan, dma_t *dma)
{
if (!dma->d_ops)
return -EINVAL;
sg_init_table(&dma->buf, 1);
if (dma_chan[chan])
return -EBUSY;
dma_chan[chan] = dma;
return 0;
}
/*
* Request DMA channel
*
* On certain platforms, we have to allocate an interrupt as well...
*/
int request_dma(unsigned int chan, const char *device_id)
{
dma_t *dma = dma_channel(chan);
int ret;
if (!dma)
goto bad_dma;
if (xchg(&dma->lock, 1) != 0)
goto busy;
dma->device_id = device_id;
dma->active = 0;
dma->invalid = 1;
ret = 0;
if (dma->d_ops->request)
ret = dma->d_ops->request(chan, dma);
if (ret)
xchg(&dma->lock, 0);
return ret;
bad_dma:
printk(KERN_ERR "dma: trying to allocate DMA%d\n", chan);
return -EINVAL;
busy:
return -EBUSY;
}
EXPORT_SYMBOL(request_dma);
/*
* Free DMA channel
*
* On certain platforms, we have to free interrupt as well...
*/
void free_dma(unsigned int chan)
{
dma_t *dma = dma_channel(chan);
if (!dma)
goto bad_dma;
if (dma->active) {
printk(KERN_ERR "dma%d: freeing active DMA\n", chan);
dma->d_ops->disable(chan, dma);
dma->active = 0;
}
if (xchg(&dma->lock, 0) != 0) {
if (dma->d_ops->free)
dma->d_ops->free(chan, dma);
return;
}
printk(KERN_ERR "dma%d: trying to free free DMA\n", chan);
return;
bad_dma:
printk(KERN_ERR "dma: trying to free DMA%d\n", chan);
}
EXPORT_SYMBOL(free_dma);
/* Set DMA Scatter-Gather list
*/
void set_dma_sg (unsigned int chan, struct scatterlist *sg, int nr_sg)
{
dma_t *dma = dma_channel(chan);
if (dma->active)
printk(KERN_ERR "dma%d: altering DMA SG while "
"DMA active\n", chan);
dma->sg = sg;
dma->sgcount = nr_sg;
dma->invalid = 1;
}
EXPORT_SYMBOL(set_dma_sg);
/* Set DMA address
*
* Copy address to the structure, and set the invalid bit
*/
void __set_dma_addr (unsigned int chan, void *addr)
{
dma_t *dma = dma_channel(chan);
if (dma->active)
printk(KERN_ERR "dma%d: altering DMA address while "
"DMA active\n", chan);
dma->sg = NULL;
dma->addr = addr;
dma->invalid = 1;
}
EXPORT_SYMBOL(__set_dma_addr);
/* Set DMA byte count
*
* Copy address to the structure, and set the invalid bit
*/
void set_dma_count (unsigned int chan, unsigned long count)
{
dma_t *dma = dma_channel(chan);
if (dma->active)
printk(KERN_ERR "dma%d: altering DMA count while "
"DMA active\n", chan);
dma->sg = NULL;
dma->count = count;
dma->invalid = 1;
}
EXPORT_SYMBOL(set_dma_count);
/* Set DMA direction mode
*/
void set_dma_mode (unsigned int chan, unsigned int mode)
{
dma_t *dma = dma_channel(chan);
if (dma->active)
printk(KERN_ERR "dma%d: altering DMA mode while "
"DMA active\n", chan);
dma->dma_mode = mode;
dma->invalid = 1;
}
EXPORT_SYMBOL(set_dma_mode);
/* Enable DMA channel
*/
void enable_dma (unsigned int chan)
{
dma_t *dma = dma_channel(chan);
if (!dma->lock)
goto free_dma;
if (dma->active == 0) {
dma->active = 1;
dma->d_ops->enable(chan, dma);
}
return;
free_dma:
printk(KERN_ERR "dma%d: trying to enable free DMA\n", chan);
BUG();
}
EXPORT_SYMBOL(enable_dma);
/* Disable DMA channel
*/
void disable_dma (unsigned int chan)
{
dma_t *dma = dma_channel(chan);
if (!dma->lock)
goto free_dma;
if (dma->active == 1) {
dma->active = 0;
dma->d_ops->disable(chan, dma);
}
return;
free_dma:
printk(KERN_ERR "dma%d: trying to disable free DMA\n", chan);
BUG();
}
EXPORT_SYMBOL(disable_dma);
/*
* Is the specified DMA channel active?
*/
int dma_channel_active(unsigned int chan)
{
dma_t *dma = dma_channel(chan);
return dma->active;
}
EXPORT_SYMBOL(dma_channel_active);
void set_dma_page(unsigned int chan, char pagenr)
{
printk(KERN_ERR "dma%d: trying to set_dma_page\n", chan);
}
EXPORT_SYMBOL(set_dma_page);
void set_dma_speed(unsigned int chan, int cycle_ns)
{
dma_t *dma = dma_channel(chan);
int ret = 0;
if (dma->d_ops->setspeed)
ret = dma->d_ops->setspeed(chan, dma, cycle_ns);
dma->speed = ret;
}
EXPORT_SYMBOL(set_dma_speed);
int get_dma_residue(unsigned int chan)
{
dma_t *dma = dma_channel(chan);
int ret = 0;
if (dma->d_ops->residue)
ret = dma->d_ops->residue(chan, dma);
return ret;
}
EXPORT_SYMBOL(get_dma_residue);
|
