blob: 1a378951da5b862bf0685e0ce5a138a3859fd757 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
42void 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 */
65void 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 */
82unsigned 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}