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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ISA DMA support functions
4 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5 */
6
7/*
8 * Defining following add some delay. Maybe this helps for some broken
9 * ISA DMA controllers.
10 */
11
12#undef HAVE_REALLY_SLOW_DMA_CONTROLLER
13
14#include <linux/export.h>
15#include <sound/core.h>
16#include <asm/dma.h>
17
18/**
19 * snd_dma_program - program an ISA DMA transfer
20 * @dma: the dma number
21 * @addr: the physical address of the buffer
22 * @size: the DMA transfer size
23 * @mode: the DMA transfer mode, DMA_MODE_XXX
24 *
25 * Programs an ISA DMA transfer for the given buffer.
26 */
27void snd_dma_program(unsigned long dma,
28 unsigned long addr, unsigned int size,
29 unsigned short mode)
30{
31 unsigned long flags;
32
33 flags = claim_dma_lock();
34 disable_dma(dma);
35 clear_dma_ff(dma);
36 set_dma_mode(dma, mode);
37 set_dma_addr(dma, addr);
38 set_dma_count(dma, size);
39 if (!(mode & DMA_MODE_NO_ENABLE))
40 enable_dma(dma);
41 release_dma_lock(flags);
42}
43EXPORT_SYMBOL(snd_dma_program);
44
45/**
46 * snd_dma_disable - stop the ISA DMA transfer
47 * @dma: the dma number
48 *
49 * Stops the ISA DMA transfer.
50 */
51void snd_dma_disable(unsigned long dma)
52{
53 unsigned long flags;
54
55 flags = claim_dma_lock();
56 clear_dma_ff(dma);
57 disable_dma(dma);
58 release_dma_lock(flags);
59}
60EXPORT_SYMBOL(snd_dma_disable);
61
62/**
63 * snd_dma_pointer - return the current pointer to DMA transfer buffer in bytes
64 * @dma: the dma number
65 * @size: the dma transfer size
66 *
67 * Return: The current pointer in DMA transfer buffer in bytes.
68 */
69unsigned int snd_dma_pointer(unsigned long dma, unsigned int size)
70{
71 unsigned long flags;
72 unsigned int result, result1;
73
74 flags = claim_dma_lock();
75 clear_dma_ff(dma);
76 if (!isa_dma_bridge_buggy)
77 disable_dma(dma);
78 result = get_dma_residue(dma);
79 /*
80 * HACK - read the counter again and choose higher value in order to
81 * avoid reading during counter lower byte roll over if the
82 * isa_dma_bridge_buggy is set.
83 */
84 result1 = get_dma_residue(dma);
85 if (!isa_dma_bridge_buggy)
86 enable_dma(dma);
87 release_dma_lock(flags);
88 if (unlikely(result < result1))
89 result = result1;
90#ifdef CONFIG_SND_DEBUG
91 if (result > size)
92 pr_err("ALSA: pointer (0x%x) for DMA #%ld is greater than transfer size (0x%x)\n", result, dma, size);
93#endif
94 if (result >= size || result == 0)
95 return 0;
96 else
97 return size - result;
98}
99EXPORT_SYMBOL(snd_dma_pointer);
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 <linux/export.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
59EXPORT_SYMBOL(snd_dma_program);
60
61/**
62 * snd_dma_disable - stop the ISA DMA transfer
63 * @dma: the dma number
64 *
65 * Stops the ISA DMA transfer.
66 */
67void 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
77EXPORT_SYMBOL(snd_dma_disable);
78
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 * Return: The current pointer in DMA transfer buffer in bytes.
85 */
86unsigned int snd_dma_pointer(unsigned long dma, unsigned int size)
87{
88 unsigned long flags;
89 unsigned int result, result1;
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);
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);
102 if (!isa_dma_bridge_buggy)
103 enable_dma(dma);
104 release_dma_lock(flags);
105 if (unlikely(result < result1))
106 result = result1;
107#ifdef CONFIG_SND_DEBUG
108 if (result > size)
109 pr_err("ALSA: 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}
116
117EXPORT_SYMBOL(snd_dma_pointer);