Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * ISA DMA support functions | |
c1017a4c | 3 | * Copyright (c) by Jaroslav Kysela <perex@perex.cz> |
1da177e4 LT |
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 | ||
d81a6d71 | 29 | #include <linux/export.h> |
1da177e4 LT |
30 | #include <sound/core.h> |
31 | #include <asm/dma.h> | |
32 | ||
33 | /** | |
34 | * snd_dma_program - program an ISA DMA transfer | |
35 | * @dma: the dma number | |
36 | * @addr: the physical address of the buffer | |
37 | * @size: the DMA transfer size | |
38 | * @mode: the DMA transfer mode, DMA_MODE_XXX | |
39 | * | |
40 | * Programs an ISA DMA transfer for the given buffer. | |
41 | */ | |
42 | void snd_dma_program(unsigned long dma, | |
43 | unsigned long addr, unsigned int size, | |
44 | unsigned short mode) | |
45 | { | |
46 | unsigned long flags; | |
47 | ||
48 | flags = claim_dma_lock(); | |
49 | disable_dma(dma); | |
50 | clear_dma_ff(dma); | |
51 | set_dma_mode(dma, mode); | |
52 | set_dma_addr(dma, addr); | |
53 | set_dma_count(dma, size); | |
54 | if (!(mode & DMA_MODE_NO_ENABLE)) | |
55 | enable_dma(dma); | |
56 | release_dma_lock(flags); | |
57 | } | |
58 | ||
c0d3fb39 TI |
59 | EXPORT_SYMBOL(snd_dma_program); |
60 | ||
1da177e4 LT |
61 | /** |
62 | * snd_dma_disable - stop the ISA DMA transfer | |
63 | * @dma: the dma number | |
64 | * | |
65 | * Stops the ISA DMA transfer. | |
66 | */ | |
67 | void snd_dma_disable(unsigned long dma) | |
68 | { | |
69 | unsigned long flags; | |
70 | ||
71 | flags = claim_dma_lock(); | |
72 | clear_dma_ff(dma); | |
73 | disable_dma(dma); | |
74 | release_dma_lock(flags); | |
75 | } | |
76 | ||
c0d3fb39 TI |
77 | EXPORT_SYMBOL(snd_dma_disable); |
78 | ||
1da177e4 LT |
79 | /** |
80 | * snd_dma_pointer - return the current pointer to DMA transfer buffer in bytes | |
81 | * @dma: the dma number | |
82 | * @size: the dma transfer size | |
83 | * | |
84 | * Returns the current pointer in DMA tranfer buffer in bytes | |
85 | */ | |
86 | unsigned int snd_dma_pointer(unsigned long dma, unsigned int size) | |
87 | { | |
88 | unsigned long flags; | |
8066e51a | 89 | unsigned int result, result1; |
1da177e4 LT |
90 | |
91 | flags = claim_dma_lock(); | |
92 | clear_dma_ff(dma); | |
93 | if (!isa_dma_bridge_buggy) | |
94 | disable_dma(dma); | |
95 | result = get_dma_residue(dma); | |
8066e51a KH |
96 | /* |
97 | * HACK - read the counter again and choose higher value in order to | |
98 | * avoid reading during counter lower byte roll over if the | |
99 | * isa_dma_bridge_buggy is set. | |
100 | */ | |
101 | result1 = get_dma_residue(dma); | |
1da177e4 LT |
102 | if (!isa_dma_bridge_buggy) |
103 | enable_dma(dma); | |
104 | release_dma_lock(flags); | |
8066e51a KH |
105 | if (unlikely(result < result1)) |
106 | result = result1; | |
1da177e4 LT |
107 | #ifdef CONFIG_SND_DEBUG |
108 | if (result > size) | |
109 | snd_printk(KERN_ERR "pointer (0x%x) for DMA #%ld is greater than transfer size (0x%x)\n", result, dma, size); | |
110 | #endif | |
111 | if (result >= size || result == 0) | |
112 | return 0; | |
113 | else | |
114 | return size - result; | |
115 | } | |
c0d3fb39 TI |
116 | |
117 | EXPORT_SYMBOL(snd_dma_pointer); |