2 * linux/arch/arm/kernel/dma.c
4 * Copyright (C) 1995-2000 Russell King
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.
10 * Front-end to the DMA handling. This handles the allocation/freeing
11 * of DMA channels, and provides a unified interface to the machines
14 #include <linux/module.h>
15 #include <linux/malloc.h>
16 #include <linux/sched.h>
17 #include <linux/mman.h>
18 #include <linux/init.h>
19 #include <linux/spinlock.h>
23 #include <asm/mach/dma.h>
25 spinlock_t dma_spin_lock
= SPIN_LOCK_UNLOCKED
;
27 #if MAX_DMA_CHANNELS > 0
29 static dma_t dma_chan
[MAX_DMA_CHANNELS
];
32 * Get dma list for /proc/dma
34 int get_dma_list(char *buf
)
40 for (i
= 0, dma
= dma_chan
; i
< MAX_DMA_CHANNELS
; i
++, dma
++)
42 p
+= sprintf(p
, "%2d: %14s %s\n", i
,
43 dma
->d_ops
->type
, dma
->device_id
);
51 * On certain platforms, we have to allocate an interrupt as well...
53 int request_dma(dmach_t channel
, const char *device_id
)
55 dma_t
*dma
= dma_chan
+ channel
;
58 if (channel
>= MAX_DMA_CHANNELS
|| !dma
->d_ops
)
61 if (xchg(&dma
->lock
, 1) != 0)
64 dma
->device_id
= device_id
;
69 if (dma
->d_ops
->request
)
70 ret
= dma
->d_ops
->request(channel
, dma
);
78 printk(KERN_ERR
"dma: trying to allocate DMA%d\n", channel
);
88 * On certain platforms, we have to free interrupt as well...
90 void free_dma(dmach_t channel
)
92 dma_t
*dma
= dma_chan
+ channel
;
94 if (channel
>= MAX_DMA_CHANNELS
|| !dma
->d_ops
)
98 printk(KERN_ERR
"dma%d: freeing active DMA\n", channel
);
99 dma
->d_ops
->disable(channel
, dma
);
103 if (xchg(&dma
->lock
, 0) != 0) {
104 if (dma
->d_ops
->free
)
105 dma
->d_ops
->free(channel
, dma
);
109 printk(KERN_ERR
"dma%d: trying to free free DMA\n", channel
);
113 printk(KERN_ERR
"dma: trying to free DMA%d\n", channel
);
116 /* Set DMA Scatter-Gather list
118 void set_dma_sg (dmach_t channel
, struct scatterlist
*sg
, int nr_sg
)
120 dma_t
*dma
= dma_chan
+ channel
;
123 dma
->sgcount
= nr_sg
;
130 * Copy address to the structure, and set the invalid bit
132 void set_dma_addr (dmach_t channel
, unsigned long physaddr
)
134 dma_t
*dma
= dma_chan
+ channel
;
137 printk(KERN_ERR
"dma%d: altering DMA address while "
138 "DMA active\n", channel
);
142 dma
->buf
.address
= bus_to_virt(physaddr
);
147 /* Set DMA byte count
149 * Copy address to the structure, and set the invalid bit
151 void set_dma_count (dmach_t channel
, unsigned long count
)
153 dma_t
*dma
= dma_chan
+ channel
;
156 printk(KERN_ERR
"dma%d: altering DMA count while "
157 "DMA active\n", channel
);
161 dma
->buf
.length
= count
;
166 /* Set DMA direction mode
168 void set_dma_mode (dmach_t channel
, dmamode_t mode
)
170 dma_t
*dma
= dma_chan
+ channel
;
173 printk(KERN_ERR
"dma%d: altering DMA mode while "
174 "DMA active\n", channel
);
176 dma
->dma_mode
= mode
;
180 /* Enable DMA channel
182 void enable_dma (dmach_t channel
)
184 dma_t
*dma
= dma_chan
+ channel
;
189 if (dma
->active
== 0) {
191 dma
->d_ops
->enable(channel
, dma
);
196 printk(KERN_ERR
"dma%d: trying to enable free DMA\n", channel
);
200 /* Disable DMA channel
202 void disable_dma (dmach_t channel
)
204 dma_t
*dma
= dma_chan
+ channel
;
209 if (dma
->active
== 1) {
211 dma
->d_ops
->disable(channel
, dma
);
216 printk(KERN_ERR
"dma%d: trying to disable free DMA\n", channel
);
220 void set_dma_page(dmach_t channel
, char pagenr
)
222 printk(KERN_ERR
"dma%d: trying to set_dma_page\n", channel
);
225 void set_dma_speed(dmach_t channel
, int cycle_ns
)
227 dma_t
*dma
= dma_chan
+ channel
;
230 if (dma
->d_ops
->setspeed
)
231 ret
= dma
->d_ops
->setspeed(channel
, dma
, cycle_ns
);
235 int get_dma_residue(dmach_t channel
)
237 dma_t
*dma
= dma_chan
+ channel
;
240 if (dma
->d_ops
->residue
)
241 ret
= dma
->d_ops
->residue(channel
, dma
);
246 void __init
init_dma(void)
248 arch_dma_init(dma_chan
);
253 int request_dma(dmach_t channel
, const char *device_id
)
258 int get_dma_residue(dmach_t channel
)
263 #define GLOBAL_ALIAS(_a,_b) asm (".set " #_a "," #_b "; .globl " #_a)
264 GLOBAL_ALIAS(disable_dma
, get_dma_residue
);
265 GLOBAL_ALIAS(enable_dma
, get_dma_residue
);
266 GLOBAL_ALIAS(free_dma
, get_dma_residue
);
267 GLOBAL_ALIAS(get_dma_list
, get_dma_residue
);
268 GLOBAL_ALIAS(set_dma_mode
, get_dma_residue
);
269 GLOBAL_ALIAS(set_dma_page
, get_dma_residue
);
270 GLOBAL_ALIAS(set_dma_count
, get_dma_residue
);
271 GLOBAL_ALIAS(set_dma_addr
, get_dma_residue
);
272 GLOBAL_ALIAS(set_dma_sg
, get_dma_residue
);
273 GLOBAL_ALIAS(set_dma_speed
, get_dma_residue
);
274 GLOBAL_ALIAS(init_dma
, get_dma_residue
);
278 EXPORT_SYMBOL(enable_dma
);
279 EXPORT_SYMBOL(disable_dma
);
280 EXPORT_SYMBOL(set_dma_addr
);
281 EXPORT_SYMBOL(set_dma_count
);
282 EXPORT_SYMBOL(set_dma_mode
);
283 EXPORT_SYMBOL(set_dma_page
);
284 EXPORT_SYMBOL(get_dma_residue
);
285 EXPORT_SYMBOL(set_dma_sg
);
286 EXPORT_SYMBOL(set_dma_speed
);