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-rw-r--r--arch/arm26/kernel/dma.c273
1 files changed, 273 insertions, 0 deletions
diff --git a/arch/arm26/kernel/dma.c b/arch/arm26/kernel/dma.c
new file mode 100644
index 000000000000..80b5a774d905
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+++ b/arch/arm26/kernel/dma.c
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1/*
2 * linux/arch/arm26/kernel/dma.c
3 *
4 * Copyright (C) 1995-2000 Russell King
5 * 2003 Ian Molton
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * Front-end to the DMA handling. This handles the allocation/freeing
12 * of DMA channels, and provides a unified interface to the machines
13 * DMA facilities.
14 */
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <linux/sched.h>
18#include <linux/mman.h>
19#include <linux/init.h>
20#include <linux/spinlock.h>
21#include <linux/errno.h>
22
23#include <asm/dma.h>
24
25DEFINE_SPINLOCK(dma_spin_lock);
26
27static dma_t dma_chan[MAX_DMA_CHANNELS];
28
29/*
30 * Get dma list for /proc/dma
31 */
32int get_dma_list(char *buf)
33{
34 dma_t *dma;
35 char *p = buf;
36 int i;
37
38 for (i = 0, dma = dma_chan; i < MAX_DMA_CHANNELS; i++, dma++)
39 if (dma->lock)
40 p += sprintf(p, "%2d: %14s %s\n", i,
41 dma->d_ops->type, dma->device_id);
42
43 return p - buf;
44}
45
46/*
47 * Request DMA channel
48 *
49 * On certain platforms, we have to allocate an interrupt as well...
50 */
51int request_dma(dmach_t channel, const char *device_id)
52{
53 dma_t *dma = dma_chan + channel;
54 int ret;
55
56 if (channel >= MAX_DMA_CHANNELS || !dma->d_ops)
57 goto bad_dma;
58
59 if (xchg(&dma->lock, 1) != 0)
60 goto busy;
61
62 dma->device_id = device_id;
63 dma->active = 0;
64 dma->invalid = 1;
65
66 ret = 0;
67 if (dma->d_ops->request)
68 ret = dma->d_ops->request(channel, dma);
69
70 if (ret)
71 xchg(&dma->lock, 0);
72
73 return ret;
74
75bad_dma:
76 printk(KERN_ERR "dma: trying to allocate DMA%d\n", channel);
77 return -EINVAL;
78
79busy:
80 return -EBUSY;
81}
82
83/*
84 * Free DMA channel
85 *
86 * On certain platforms, we have to free interrupt as well...
87 */
88void free_dma(dmach_t channel)
89{
90 dma_t *dma = dma_chan + channel;
91
92 if (channel >= MAX_DMA_CHANNELS || !dma->d_ops)
93 goto bad_dma;
94
95 if (dma->active) {
96 printk(KERN_ERR "dma%d: freeing active DMA\n", channel);
97 dma->d_ops->disable(channel, dma);
98 dma->active = 0;
99 }
100
101 if (xchg(&dma->lock, 0) != 0) {
102 if (dma->d_ops->free)
103 dma->d_ops->free(channel, dma);
104 return;
105 }
106
107 printk(KERN_ERR "dma%d: trying to free free DMA\n", channel);
108 return;
109
110bad_dma:
111 printk(KERN_ERR "dma: trying to free DMA%d\n", channel);
112}
113
114/* Set DMA Scatter-Gather list
115 */
116void set_dma_sg (dmach_t channel, struct scatterlist *sg, int nr_sg)
117{
118 dma_t *dma = dma_chan + channel;
119
120 if (dma->active)
121 printk(KERN_ERR "dma%d: altering DMA SG while "
122 "DMA active\n", channel);
123
124 dma->sg = sg;
125 dma->sgcount = nr_sg;
126 dma->using_sg = 1;
127 dma->invalid = 1;
128}
129
130/* Set DMA address
131 *
132 * Copy address to the structure, and set the invalid bit
133 */
134void set_dma_addr (dmach_t channel, unsigned long physaddr)
135{
136 dma_t *dma = dma_chan + channel;
137
138 if (dma->active)
139 printk(KERN_ERR "dma%d: altering DMA address while "
140 "DMA active\n", channel);
141
142 dma->sg = &dma->buf;
143 dma->sgcount = 1;
144 dma->buf.__address = (char *)physaddr;//FIXME - not pretty
145 dma->using_sg = 0;
146 dma->invalid = 1;
147}
148
149/* Set DMA byte count
150 *
151 * Copy address to the structure, and set the invalid bit
152 */
153void set_dma_count (dmach_t channel, unsigned long count)
154{
155 dma_t *dma = dma_chan + channel;
156
157 if (dma->active)
158 printk(KERN_ERR "dma%d: altering DMA count while "
159 "DMA active\n", channel);
160
161 dma->sg = &dma->buf;
162 dma->sgcount = 1;
163 dma->buf.length = count;
164 dma->using_sg = 0;
165 dma->invalid = 1;
166}
167
168/* Set DMA direction mode
169 */
170void set_dma_mode (dmach_t channel, dmamode_t mode)
171{
172 dma_t *dma = dma_chan + channel;
173
174 if (dma->active)
175 printk(KERN_ERR "dma%d: altering DMA mode while "
176 "DMA active\n", channel);
177
178 dma->dma_mode = mode;
179 dma->invalid = 1;
180}
181
182/* Enable DMA channel
183 */
184void enable_dma (dmach_t channel)
185{
186 dma_t *dma = dma_chan + channel;
187
188 if (!dma->lock)
189 goto free_dma;
190
191 if (dma->active == 0) {
192 dma->active = 1;
193 dma->d_ops->enable(channel, dma);
194 }
195 return;
196
197free_dma:
198 printk(KERN_ERR "dma%d: trying to enable free DMA\n", channel);
199 BUG();
200}
201
202/* Disable DMA channel
203 */
204void disable_dma (dmach_t channel)
205{
206 dma_t *dma = dma_chan + channel;
207
208 if (!dma->lock)
209 goto free_dma;
210
211 if (dma->active == 1) {
212 dma->active = 0;
213 dma->d_ops->disable(channel, dma);
214 }
215 return;
216
217free_dma:
218 printk(KERN_ERR "dma%d: trying to disable free DMA\n", channel);
219 BUG();
220}
221
222/*
223 * Is the specified DMA channel active?
224 */
225int dma_channel_active(dmach_t channel)
226{
227 return dma_chan[channel].active;
228}
229
230void set_dma_page(dmach_t channel, char pagenr)
231{
232 printk(KERN_ERR "dma%d: trying to set_dma_page\n", channel);
233}
234
235void set_dma_speed(dmach_t channel, int cycle_ns)
236{
237 dma_t *dma = dma_chan + channel;
238 int ret = 0;
239
240 if (dma->d_ops->setspeed)
241 ret = dma->d_ops->setspeed(channel, dma, cycle_ns);
242 dma->speed = ret;
243}
244
245int get_dma_residue(dmach_t channel)
246{
247 dma_t *dma = dma_chan + channel;
248 int ret = 0;
249
250 if (dma->d_ops->residue)
251 ret = dma->d_ops->residue(channel, dma);
252
253 return ret;
254}
255
256void __init init_dma(void)
257{
258 arch_dma_init(dma_chan);
259}
260
261EXPORT_SYMBOL(request_dma);
262EXPORT_SYMBOL(free_dma);
263EXPORT_SYMBOL(enable_dma);
264EXPORT_SYMBOL(disable_dma);
265EXPORT_SYMBOL(set_dma_addr);
266EXPORT_SYMBOL(set_dma_count);
267EXPORT_SYMBOL(set_dma_mode);
268EXPORT_SYMBOL(set_dma_page);
269EXPORT_SYMBOL(get_dma_residue);
270EXPORT_SYMBOL(set_dma_sg);
271EXPORT_SYMBOL(set_dma_speed);
272
273EXPORT_SYMBOL(dma_spin_lock);