Commit | Line | Data |
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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 | */ | |
1df81302 | 33 | int request_dma(unsigned int chan, const char *device_id) |
1da177e4 | 34 | { |
1df81302 | 35 | dma_t *dma = dma_chan + chan; |
1da177e4 LT |
36 | int ret; |
37 | ||
1df81302 | 38 | if (chan >= MAX_DMA_CHANNELS || !dma->d_ops) |
1da177e4 LT |
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) | |
1df81302 | 50 | ret = dma->d_ops->request(chan, dma); |
1da177e4 LT |
51 | |
52 | if (ret) | |
53 | xchg(&dma->lock, 0); | |
54 | ||
55 | return ret; | |
56 | ||
57 | bad_dma: | |
1df81302 | 58 | printk(KERN_ERR "dma: trying to allocate DMA%d\n", chan); |
1da177e4 LT |
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 | */ | |
1df81302 | 71 | void free_dma(unsigned int chan) |
1da177e4 | 72 | { |
1df81302 | 73 | dma_t *dma = dma_chan + chan; |
1da177e4 | 74 | |
1df81302 | 75 | if (chan >= MAX_DMA_CHANNELS || !dma->d_ops) |
1da177e4 LT |
76 | goto bad_dma; |
77 | ||
78 | if (dma->active) { | |
1df81302 RK |
79 | printk(KERN_ERR "dma%d: freeing active DMA\n", chan); |
80 | dma->d_ops->disable(chan, dma); | |
1da177e4 LT |
81 | dma->active = 0; |
82 | } | |
83 | ||
84 | if (xchg(&dma->lock, 0) != 0) { | |
85 | if (dma->d_ops->free) | |
1df81302 | 86 | dma->d_ops->free(chan, dma); |
1da177e4 LT |
87 | return; |
88 | } | |
89 | ||
1df81302 | 90 | printk(KERN_ERR "dma%d: trying to free free DMA\n", chan); |
1da177e4 LT |
91 | return; |
92 | ||
93 | bad_dma: | |
1df81302 | 94 | printk(KERN_ERR "dma: trying to free DMA%d\n", chan); |
1da177e4 | 95 | } |
d7b4a756 | 96 | EXPORT_SYMBOL(free_dma); |
1da177e4 LT |
97 | |
98 | /* Set DMA Scatter-Gather list | |
99 | */ | |
1df81302 | 100 | void set_dma_sg (unsigned int chan, struct scatterlist *sg, int nr_sg) |
1da177e4 | 101 | { |
1df81302 | 102 | dma_t *dma = dma_chan + chan; |
1da177e4 LT |
103 | |
104 | if (dma->active) | |
105 | printk(KERN_ERR "dma%d: altering DMA SG while " | |
1df81302 | 106 | "DMA active\n", chan); |
1da177e4 LT |
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 | */ | |
1df81302 | 118 | void __set_dma_addr (unsigned int chan, void *addr) |
1da177e4 | 119 | { |
1df81302 | 120 | dma_t *dma = dma_chan + chan; |
1da177e4 LT |
121 | |
122 | if (dma->active) | |
123 | printk(KERN_ERR "dma%d: altering DMA address while " | |
1df81302 | 124 | "DMA active\n", chan); |
1da177e4 | 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 | */ | |
1df81302 | 136 | void set_dma_count (unsigned int chan, unsigned long count) |
1da177e4 | 137 | { |
1df81302 | 138 | dma_t *dma = dma_chan + chan; |
1da177e4 LT |
139 | |
140 | if (dma->active) | |
141 | printk(KERN_ERR "dma%d: altering DMA count while " | |
1df81302 | 142 | "DMA active\n", chan); |
1da177e4 | 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 | */ | |
1df81302 | 152 | void set_dma_mode (unsigned int chan, dmamode_t mode) |
1da177e4 | 153 | { |
1df81302 | 154 | dma_t *dma = dma_chan + chan; |
1da177e4 LT |
155 | |
156 | if (dma->active) | |
157 | printk(KERN_ERR "dma%d: altering DMA mode while " | |
1df81302 | 158 | "DMA active\n", chan); |
1da177e4 LT |
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 | */ | |
1df81302 | 167 | void enable_dma (unsigned int chan) |
1da177e4 | 168 | { |
1df81302 | 169 | dma_t *dma = dma_chan + chan; |
1da177e4 LT |
170 | |
171 | if (!dma->lock) | |
172 | goto free_dma; | |
173 | ||
174 | if (dma->active == 0) { | |
175 | dma->active = 1; | |
1df81302 | 176 | dma->d_ops->enable(chan, dma); |
1da177e4 LT |
177 | } |
178 | return; | |
179 | ||
180 | free_dma: | |
1df81302 | 181 | printk(KERN_ERR "dma%d: trying to enable free DMA\n", chan); |
1da177e4 LT |
182 | BUG(); |
183 | } | |
d7b4a756 | 184 | EXPORT_SYMBOL(enable_dma); |
1da177e4 LT |
185 | |
186 | /* Disable DMA channel | |
187 | */ | |
1df81302 | 188 | void disable_dma (unsigned int chan) |
1da177e4 | 189 | { |
1df81302 | 190 | dma_t *dma = dma_chan + chan; |
1da177e4 LT |
191 | |
192 | if (!dma->lock) | |
193 | goto free_dma; | |
194 | ||
195 | if (dma->active == 1) { | |
196 | dma->active = 0; | |
1df81302 | 197 | dma->d_ops->disable(chan, dma); |
1da177e4 LT |
198 | } |
199 | return; | |
200 | ||
201 | free_dma: | |
1df81302 | 202 | printk(KERN_ERR "dma%d: trying to disable free DMA\n", chan); |
1da177e4 LT |
203 | BUG(); |
204 | } | |
d7b4a756 | 205 | EXPORT_SYMBOL(disable_dma); |
1da177e4 LT |
206 | |
207 | /* | |
208 | * Is the specified DMA channel active? | |
209 | */ | |
1df81302 | 210 | int dma_channel_active(unsigned int chan) |
1da177e4 | 211 | { |
1df81302 | 212 | return dma_chan[chan].active; |
1da177e4 | 213 | } |
ec14d796 | 214 | EXPORT_SYMBOL(dma_channel_active); |
1da177e4 | 215 | |
1df81302 | 216 | void set_dma_page(unsigned int chan, char pagenr) |
1da177e4 | 217 | { |
1df81302 | 218 | printk(KERN_ERR "dma%d: trying to set_dma_page\n", chan); |
1da177e4 | 219 | } |
d7b4a756 | 220 | EXPORT_SYMBOL(set_dma_page); |
1da177e4 | 221 | |
1df81302 | 222 | void set_dma_speed(unsigned int chan, int cycle_ns) |
1da177e4 | 223 | { |
1df81302 | 224 | dma_t *dma = dma_chan + chan; |
1da177e4 LT |
225 | int ret = 0; |
226 | ||
227 | if (dma->d_ops->setspeed) | |
1df81302 | 228 | ret = dma->d_ops->setspeed(chan, dma, cycle_ns); |
1da177e4 LT |
229 | dma->speed = ret; |
230 | } | |
d7b4a756 | 231 | EXPORT_SYMBOL(set_dma_speed); |
1da177e4 | 232 | |
1df81302 | 233 | int get_dma_residue(unsigned int chan) |
1da177e4 | 234 | { |
1df81302 | 235 | dma_t *dma = dma_chan + chan; |
1da177e4 LT |
236 | int ret = 0; |
237 | ||
238 | if (dma->d_ops->residue) | |
1df81302 | 239 | ret = dma->d_ops->residue(chan, dma); |
1da177e4 LT |
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); |