1 /*
2 * ISA DMA support functions
3 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4 *
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 as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 */
21
22 /*
23 * Defining following add some delay. Maybe this helps for some broken
24 * ISA DMA controllers.
25 */
26
27 #undef HAVE_REALLY_SLOW_DMA_CONTROLLER
28
29 #include <sound/core.h>
30 #include <asm/dma.h>
31
32 /**
33 * snd_dma_program - program an ISA DMA transfer
34 * @dma: the dma number
35 * @addr: the physical address of the buffer
36 * @size: the DMA transfer size
37 * @mode: the DMA transfer mode, DMA_MODE_XXX
38 *
39 * Programs an ISA DMA transfer for the given buffer.
40 */
41 void snd_dma_program(unsigned long dma,
42 unsigned long addr, unsigned int size,
43 unsigned short mode)
44 {
45 unsigned long flags;
46
47 flags = claim_dma_lock();
48 disable_dma(dma);
49 clear_dma_ff(dma);
50 set_dma_mode(dma, mode);
51 set_dma_addr(dma, addr);
52 set_dma_count(dma, size);
53 if (!(mode & DMA_MODE_NO_ENABLE))
54 enable_dma(dma);
55 release_dma_lock(flags);
56 }
57
58 EXPORT_SYMBOL(snd_dma_program);
59
60 /**
61 * snd_dma_disable - stop the ISA DMA transfer
62 * @dma: the dma number
63 *
64 * Stops the ISA DMA transfer.
65 */
66 void snd_dma_disable(unsigned long dma)
67 {
68 unsigned long flags;
69
70 flags = claim_dma_lock();
71 clear_dma_ff(dma);
72 disable_dma(dma);
73 release_dma_lock(flags);
74 }
75
76 EXPORT_SYMBOL(snd_dma_disable);
77
78 /**
79 * snd_dma_pointer - return the current pointer to DMA transfer buffer in bytes
80 * @dma: the dma number
81 * @size: the dma transfer size
82 *
83 * Returns the current pointer in DMA tranfer buffer in bytes
84 */
85 unsigned int snd_dma_pointer(unsigned long dma, unsigned int size)
86 {
87 unsigned long flags;
88 unsigned int result;
89
90 flags = claim_dma_lock();
91 clear_dma_ff(dma);
92 if (!isa_dma_bridge_buggy)
93 disable_dma(dma);
94 result = get_dma_residue(dma);
95 if (!isa_dma_bridge_buggy)
96 enable_dma(dma);
97 release_dma_lock(flags);
98 #ifdef CONFIG_SND_DEBUG
99 if (result > size)
100 snd_printk(KERN_ERR "pointer (0x%x) for DMA #%ld is greater than transfer size (0x%x)\n", result, dma, size);
101 #endif
102 if (result >= size || result == 0)
103 return 0;
104 else
105 return size - result;
106 }
107
108 EXPORT_SYMBOL(snd_dma_pointer);
109
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