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1da177e4 LT |
1 | /* |
2 | * ISA DMA support functions | |
3 | * Copyright (c) by Jaroslav Kysela <perex@suse.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/driver.h> | |
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 | ||
59 | /** | |
60 | * snd_dma_disable - stop the ISA DMA transfer | |
61 | * @dma: the dma number | |
62 | * | |
63 | * Stops the ISA DMA transfer. | |
64 | */ | |
65 | void snd_dma_disable(unsigned long dma) | |
66 | { | |
67 | unsigned long flags; | |
68 | ||
69 | flags = claim_dma_lock(); | |
70 | clear_dma_ff(dma); | |
71 | disable_dma(dma); | |
72 | release_dma_lock(flags); | |
73 | } | |
74 | ||
75 | /** | |
76 | * snd_dma_pointer - return the current pointer to DMA transfer buffer in bytes | |
77 | * @dma: the dma number | |
78 | * @size: the dma transfer size | |
79 | * | |
80 | * Returns the current pointer in DMA tranfer buffer in bytes | |
81 | */ | |
82 | unsigned int snd_dma_pointer(unsigned long dma, unsigned int size) | |
83 | { | |
84 | unsigned long flags; | |
85 | unsigned int result; | |
86 | ||
87 | flags = claim_dma_lock(); | |
88 | clear_dma_ff(dma); | |
89 | if (!isa_dma_bridge_buggy) | |
90 | disable_dma(dma); | |
91 | result = get_dma_residue(dma); | |
92 | if (!isa_dma_bridge_buggy) | |
93 | enable_dma(dma); | |
94 | release_dma_lock(flags); | |
95 | #ifdef CONFIG_SND_DEBUG | |
96 | if (result > size) | |
97 | snd_printk(KERN_ERR "pointer (0x%x) for DMA #%ld is greater than transfer size (0x%x)\n", result, dma, size); | |
98 | #endif | |
99 | if (result >= size || result == 0) | |
100 | return 0; | |
101 | else | |
102 | return size - result; | |
103 | } |