1 /*
2 * Helper functions for indirect PCM data transfer to a simple FIFO in
3 * hardware (small, no possibility to read "hardware io position",
4 * updating position done by interrupt, ...)
5 *
6 * Copyright (c) by 2007 Joachim Foerster <JOFT@gmx.de>
7 *
8 * Based on "pcm-indirect.h" (alsa-driver-1.0.13) by
9 *
10 * Copyright (c) by Takashi Iwai <tiwai@suse.de>
11 * Jaroslav Kysela <perex@suse.cz>
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
17 *
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
22 *
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 */
27
28 #ifndef __SOUND_PCM_INDIRECT2_H
29 #define __SOUND_PCM_INDIRECT2_H
30
31 /* struct snd_pcm_substream, struct snd_pcm_runtime, snd_pcm_uframes_t */
32 #include <sound/pcm.h>
33
34 /* Debug options for code which may be removed completely in a final version */
35 #ifdef CONFIG_SND_DEBUG
36 #define SND_PCM_INDIRECT2_STAT /* turn on some "statistics" about the
37 * process of copying bytes from the
38 * intermediate buffer to the hardware
39 * fifo and the other way round
40 */
41 #endif
42
43 struct snd_pcm_indirect2 {
44 unsigned int hw_buffer_size; /* Byte size of hardware buffer */
45 int hw_ready; /* playback: 1 = hw fifo has room left,
46 * 0 = hw fifo is full
47 */
48 unsigned int min_multiple;
49 int min_periods; /* counts number of min. periods until
50 * min_multiple is reached
51 */
52 int min_period_count; /* counts bytes to count number of
53 * min. periods
54 */
55
56 unsigned int sw_buffer_size; /* Byte size of software buffer */
57
58 /* sw_data: position in intermediate buffer, where we will read (or
59 * write) from/to next time (to transfer data to/from HW)
60 */
61 unsigned int sw_data; /* Offset to next dst (or src) in sw
62 * ring buffer
63 */
64 /* easiest case (playback):
65 * sw_data is nearly the same as ~ runtime->control->appl_ptr, with the
66 * exception that sw_data is "behind" by the number if bytes ALSA wrote
67 * to the intermediate buffer last time.
68 * A call to ack() callback synchronizes both indirectly.
69 */
70
71 /* We have no real sw_io pointer here. Usually sw_io is pointing to the
72 * current playback/capture position _inside_ the hardware. Devices
73 * with plain FIFOs often have no possibility to publish this position.
74 * So we say: if sw_data is updated, that means bytes were copied to
75 * the hardware, we increase sw_io by that amount, because there have
76 * to be as much bytes which were played. So sw_io will stay behind
77 * sw_data all the time and has to converge to sw_data at the end of
78 * playback.
79 */
80 unsigned int sw_io; /* Current software pointer in bytes */
81
82 /* sw_ready: number of bytes ALSA copied to the intermediate buffer, so
83 * it represents the number of bytes which wait for transfer to the HW
84 */
85 int sw_ready; /* Bytes ready to be transferred to/from hw */
86
87 /* appl_ptr: last known position of ALSA (where ALSA is going to write
88 * next time into the intermediate buffer
89 */
90 snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */
91
92 unsigned int bytes2hw;
93 int check_alignment;
94
95 #ifdef SND_PCM_INDIRECT2_STAT
96 unsigned int zeros2hw;
97 unsigned int mul_elapsed;
98 unsigned int mul_elapsed_real;
99 unsigned long firstbytetime;
100 unsigned long lastbytetime;
101 unsigned long firstzerotime;
102 unsigned int byte_sizes[64];
103 unsigned int zero_sizes[64];
104 unsigned int min_adds[8];
105 unsigned int mul_adds[8];
106 unsigned int zero_times[3750]; /* = 15s */
107 unsigned int zero_times_saved;
108 unsigned int zero_times_notsaved;
109 unsigned int irq_occured;
110 unsigned int pointer_calls;
111 unsigned int lastdifftime;
112 #endif
113 };
114
115 typedef size_t (*snd_pcm_indirect2_copy_t) (struct snd_pcm_substream *substream,
116 struct snd_pcm_indirect2 *rec,
117 size_t bytes);
118 typedef size_t (*snd_pcm_indirect2_zero_t) (struct snd_pcm_substream *substream,
119 struct snd_pcm_indirect2 *rec);
120
121 #ifdef SND_PCM_INDIRECT2_STAT
122 void snd_pcm_indirect2_stat(struct snd_pcm_substream *substream,
123 struct snd_pcm_indirect2 *rec);
124 #endif
125
126 snd_pcm_uframes_t
127 snd_pcm_indirect2_pointer(struct snd_pcm_substream *substream,
128 struct snd_pcm_indirect2 *rec);
129 void
130 snd_pcm_indirect2_playback_interrupt(struct snd_pcm_substream *substream,
131 struct snd_pcm_indirect2 *rec,
132 snd_pcm_indirect2_copy_t copy,
133 snd_pcm_indirect2_zero_t zero);
134 void
135 snd_pcm_indirect2_capture_interrupt(struct snd_pcm_substream *substream,
136 struct snd_pcm_indirect2 *rec,
137 snd_pcm_indirect2_copy_t copy,
138 snd_pcm_indirect2_zero_t null);
139
140 #endif /* __SOUND_PCM_INDIRECT2_H */
141
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