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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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