Merge git://git.infradead.org/mtd-2.6
[linux-2.6] / arch / arm / kernel / dma.c
1 /*
2  *  linux/arch/arm/kernel/dma.c
3  *
4  *  Copyright (C) 1995-2000 Russell King
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  *  Front-end to the DMA handling.  This handles the allocation/freeing
11  *  of DMA channels, and provides a unified interface to the machines
12  *  DMA facilities.
13  */
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/spinlock.h>
17 #include <linux/errno.h>
18
19 #include <asm/dma.h>
20
21 #include <asm/mach/dma.h>
22
23 DEFINE_SPINLOCK(dma_spin_lock);
24 EXPORT_SYMBOL(dma_spin_lock);
25
26 static dma_t dma_chan[MAX_DMA_CHANNELS];
27
28 /*
29  * Request DMA channel
30  *
31  * On certain platforms, we have to allocate an interrupt as well...
32  */
33 int request_dma(dmach_t channel, const char *device_id)
34 {
35         dma_t *dma = dma_chan + channel;
36         int ret;
37
38         if (channel >= MAX_DMA_CHANNELS || !dma->d_ops)
39                 goto bad_dma;
40
41         if (xchg(&dma->lock, 1) != 0)
42                 goto busy;
43
44         dma->device_id = device_id;
45         dma->active    = 0;
46         dma->invalid   = 1;
47
48         ret = 0;
49         if (dma->d_ops->request)
50                 ret = dma->d_ops->request(channel, dma);
51
52         if (ret)
53                 xchg(&dma->lock, 0);
54
55         return ret;
56
57 bad_dma:
58         printk(KERN_ERR "dma: trying to allocate DMA%d\n", channel);
59         return -EINVAL;
60
61 busy:
62         return -EBUSY;
63 }
64 EXPORT_SYMBOL(request_dma);
65
66 /*
67  * Free DMA channel
68  *
69  * On certain platforms, we have to free interrupt as well...
70  */
71 void free_dma(dmach_t channel)
72 {
73         dma_t *dma = dma_chan + channel;
74
75         if (channel >= MAX_DMA_CHANNELS || !dma->d_ops)
76                 goto bad_dma;
77
78         if (dma->active) {
79                 printk(KERN_ERR "dma%d: freeing active DMA\n", channel);
80                 dma->d_ops->disable(channel, dma);
81                 dma->active = 0;
82         }
83
84         if (xchg(&dma->lock, 0) != 0) {
85                 if (dma->d_ops->free)
86                         dma->d_ops->free(channel, dma);
87                 return;
88         }
89
90         printk(KERN_ERR "dma%d: trying to free free DMA\n", channel);
91         return;
92
93 bad_dma:
94         printk(KERN_ERR "dma: trying to free DMA%d\n", channel);
95 }
96 EXPORT_SYMBOL(free_dma);
97
98 /* Set DMA Scatter-Gather list
99  */
100 void set_dma_sg (dmach_t channel, struct scatterlist *sg, int nr_sg)
101 {
102         dma_t *dma = dma_chan + channel;
103
104         if (dma->active)
105                 printk(KERN_ERR "dma%d: altering DMA SG while "
106                        "DMA active\n", channel);
107
108         dma->sg = sg;
109         dma->sgcount = nr_sg;
110         dma->invalid = 1;
111 }
112 EXPORT_SYMBOL(set_dma_sg);
113
114 /* Set DMA address
115  *
116  * Copy address to the structure, and set the invalid bit
117  */
118 void __set_dma_addr (dmach_t channel, void *addr)
119 {
120         dma_t *dma = dma_chan + channel;
121
122         if (dma->active)
123                 printk(KERN_ERR "dma%d: altering DMA address while "
124                        "DMA active\n", channel);
125
126         dma->sg = NULL;
127         dma->addr = addr;
128         dma->invalid = 1;
129 }
130 EXPORT_SYMBOL(__set_dma_addr);
131
132 /* Set DMA byte count
133  *
134  * Copy address to the structure, and set the invalid bit
135  */
136 void set_dma_count (dmach_t channel, unsigned long count)
137 {
138         dma_t *dma = dma_chan + channel;
139
140         if (dma->active)
141                 printk(KERN_ERR "dma%d: altering DMA count while "
142                        "DMA active\n", channel);
143
144         dma->sg = NULL;
145         dma->count = count;
146         dma->invalid = 1;
147 }
148 EXPORT_SYMBOL(set_dma_count);
149
150 /* Set DMA direction mode
151  */
152 void set_dma_mode (dmach_t channel, dmamode_t mode)
153 {
154         dma_t *dma = dma_chan + channel;
155
156         if (dma->active)
157                 printk(KERN_ERR "dma%d: altering DMA mode while "
158                        "DMA active\n", channel);
159
160         dma->dma_mode = mode;
161         dma->invalid = 1;
162 }
163 EXPORT_SYMBOL(set_dma_mode);
164
165 /* Enable DMA channel
166  */
167 void enable_dma (dmach_t channel)
168 {
169         dma_t *dma = dma_chan + channel;
170
171         if (!dma->lock)
172                 goto free_dma;
173
174         if (dma->active == 0) {
175                 dma->active = 1;
176                 dma->d_ops->enable(channel, dma);
177         }
178         return;
179
180 free_dma:
181         printk(KERN_ERR "dma%d: trying to enable free DMA\n", channel);
182         BUG();
183 }
184 EXPORT_SYMBOL(enable_dma);
185
186 /* Disable DMA channel
187  */
188 void disable_dma (dmach_t channel)
189 {
190         dma_t *dma = dma_chan + channel;
191
192         if (!dma->lock)
193                 goto free_dma;
194
195         if (dma->active == 1) {
196                 dma->active = 0;
197                 dma->d_ops->disable(channel, dma);
198         }
199         return;
200
201 free_dma:
202         printk(KERN_ERR "dma%d: trying to disable free DMA\n", channel);
203         BUG();
204 }
205 EXPORT_SYMBOL(disable_dma);
206
207 /*
208  * Is the specified DMA channel active?
209  */
210 int dma_channel_active(dmach_t channel)
211 {
212         return dma_chan[channel].active;
213 }
214 EXPORT_SYMBOL(dma_channel_active);
215
216 void set_dma_page(dmach_t channel, char pagenr)
217 {
218         printk(KERN_ERR "dma%d: trying to set_dma_page\n", channel);
219 }
220 EXPORT_SYMBOL(set_dma_page);
221
222 void set_dma_speed(dmach_t channel, int cycle_ns)
223 {
224         dma_t *dma = dma_chan + channel;
225         int ret = 0;
226
227         if (dma->d_ops->setspeed)
228                 ret = dma->d_ops->setspeed(channel, dma, cycle_ns);
229         dma->speed = ret;
230 }
231 EXPORT_SYMBOL(set_dma_speed);
232
233 int get_dma_residue(dmach_t channel)
234 {
235         dma_t *dma = dma_chan + channel;
236         int ret = 0;
237
238         if (dma->d_ops->residue)
239                 ret = dma->d_ops->residue(channel, dma);
240
241         return ret;
242 }
243 EXPORT_SYMBOL(get_dma_residue);
244
245 static int __init init_dma(void)
246 {
247         arch_dma_init(dma_chan);
248         return 0;
249 }
250
251 core_initcall(init_dma);