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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 <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 */
41void 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
58EXPORT_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 */
66void 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
76EXPORT_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 */
85unsigned int snd_dma_pointer(unsigned long dma, unsigned int size)
86{
87 unsigned long flags;
88 unsigned int result, result1;
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 /*
96 * HACK - read the counter again and choose higher value in order to
97 * avoid reading during counter lower byte roll over if the
98 * isa_dma_bridge_buggy is set.
99 */
100 result1 = get_dma_residue(dma);
101 if (!isa_dma_bridge_buggy)
102 enable_dma(dma);
103 release_dma_lock(flags);
104 if (unlikely(result < result1))
105 result = result1;
106#ifdef CONFIG_SND_DEBUG
107 if (result > size)
108 snd_printk(KERN_ERR "pointer (0x%x) for DMA #%ld is greater than transfer size (0x%x)\n", result, dma, size);
109#endif
110 if (result >= size || result == 0)
111 return 0;
112 else
113 return size - result;
114}
115
116EXPORT_SYMBOL(snd_dma_pointer);