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1da177e4 LT |
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> | |
1da177e4 LT |
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); | |
d7b4a756 | 24 | EXPORT_SYMBOL(dma_spin_lock); |
1da177e4 | 25 | |
1da177e4 LT |
26 | static dma_t dma_chan[MAX_DMA_CHANNELS]; |
27 | ||
1da177e4 LT |
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 | } | |
d7b4a756 | 64 | EXPORT_SYMBOL(request_dma); |
1da177e4 LT |
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 | } | |
d7b4a756 | 96 | EXPORT_SYMBOL(free_dma); |
1da177e4 LT |
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; | |
1da177e4 LT |
110 | dma->invalid = 1; |
111 | } | |
d7b4a756 | 112 | EXPORT_SYMBOL(set_dma_sg); |
1da177e4 LT |
113 | |
114 | /* Set DMA address | |
115 | * | |
116 | * Copy address to the structure, and set the invalid bit | |
117 | */ | |
333c9624 | 118 | void __set_dma_addr (dmach_t channel, void *addr) |
1da177e4 LT |
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 | ||
7cdad482 RK |
126 | dma->sg = NULL; |
127 | dma->addr = addr; | |
1da177e4 LT |
128 | dma->invalid = 1; |
129 | } | |
d7b4a756 | 130 | EXPORT_SYMBOL(__set_dma_addr); |
1da177e4 LT |
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 | ||
7cdad482 RK |
144 | dma->sg = NULL; |
145 | dma->count = count; | |
1da177e4 LT |
146 | dma->invalid = 1; |
147 | } | |
d7b4a756 | 148 | EXPORT_SYMBOL(set_dma_count); |
1da177e4 LT |
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 | } | |
d7b4a756 | 163 | EXPORT_SYMBOL(set_dma_mode); |
1da177e4 LT |
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 | } | |
d7b4a756 | 184 | EXPORT_SYMBOL(enable_dma); |
1da177e4 LT |
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 | } | |
d7b4a756 | 205 | EXPORT_SYMBOL(disable_dma); |
1da177e4 LT |
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 | } | |
ec14d796 | 214 | EXPORT_SYMBOL(dma_channel_active); |
1da177e4 LT |
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 | } | |
d7b4a756 | 220 | EXPORT_SYMBOL(set_dma_page); |
1da177e4 LT |
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 | } | |
d7b4a756 | 231 | EXPORT_SYMBOL(set_dma_speed); |
1da177e4 LT |
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 | } | |
d7b4a756 | 243 | EXPORT_SYMBOL(get_dma_residue); |
1da177e4 | 244 | |
6842b929 | 245 | static int __init init_dma(void) |
1da177e4 LT |
246 | { |
247 | arch_dma_init(dma_chan); | |
6842b929 | 248 | return 0; |
1da177e4 LT |
249 | } |
250 | ||
6842b929 | 251 | core_initcall(init_dma); |