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1 | /* |
2 | * Helper functions for indirect PCM data transfer |
3 | * |
4 | * Copyright (c) by Takashi Iwai <tiwai@suse.de> |
5 | * Jaroslav Kysela <perex@perex.cz> |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify |
8 | * it under the terms of the GNU General Public License as published by |
9 | * the Free Software Foundation; either version 2 of the License, or |
10 | * (at your option) any later version. |
11 | * |
12 | * This program is distributed in the hope that it will be useful, |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
15 | * GNU General Public License for more details. |
16 | * |
17 | * You should have received a copy of the GNU General Public License |
18 | * along with this program; if not, write to the Free Software |
19 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
20 | */ |
21 | |
22 | #ifndef __SOUND_PCM_INDIRECT_H |
23 | #define __SOUND_PCM_INDIRECT_H |
24 | |
25 | #include <sound/pcm.h> |
26 | |
27 | struct snd_pcm_indirect { |
28 | unsigned int hw_buffer_size; /* Byte size of hardware buffer */ |
29 | unsigned int hw_queue_size; /* Max queue size of hw buffer (0 = buffer size) */ |
30 | unsigned int hw_data; /* Offset to next dst (or src) in hw ring buffer */ |
31 | unsigned int hw_io; /* Ring buffer hw pointer */ |
32 | int hw_ready; /* Bytes ready for play (or captured) in hw ring buffer */ |
33 | unsigned int sw_buffer_size; /* Byte size of software buffer */ |
34 | unsigned int sw_data; /* Offset to next dst (or src) in sw ring buffer */ |
35 | unsigned int sw_io; /* Current software pointer in bytes */ |
36 | int sw_ready; /* Bytes ready to be transferred to/from hw */ |
37 | snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */ |
38 | }; |
39 | |
40 | typedef void (*snd_pcm_indirect_copy_t)(struct snd_pcm_substream *substream, |
41 | struct snd_pcm_indirect *rec, size_t bytes); |
42 | |
43 | /* |
44 | * helper function for playback ack callback |
45 | */ |
46 | static inline void |
47 | snd_pcm_indirect_playback_transfer(struct snd_pcm_substream *substream, |
48 | struct snd_pcm_indirect *rec, |
49 | snd_pcm_indirect_copy_t copy) |
50 | { |
51 | struct snd_pcm_runtime *runtime = substream->runtime; |
52 | snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr; |
53 | snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr; |
54 | int qsize; |
55 | |
56 | if (diff) { |
57 | if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2)) |
58 | diff += runtime->boundary; |
59 | rec->sw_ready += (int)frames_to_bytes(runtime, diff); |
60 | rec->appl_ptr = appl_ptr; |
61 | } |
62 | qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size; |
63 | while (rec->hw_ready < qsize && rec->sw_ready > 0) { |
64 | unsigned int hw_to_end = rec->hw_buffer_size - rec->hw_data; |
65 | unsigned int sw_to_end = rec->sw_buffer_size - rec->sw_data; |
66 | unsigned int bytes = qsize - rec->hw_ready; |
67 | if (rec->sw_ready < (int)bytes) |
68 | bytes = rec->sw_ready; |
69 | if (hw_to_end < bytes) |
70 | bytes = hw_to_end; |
71 | if (sw_to_end < bytes) |
72 | bytes = sw_to_end; |
73 | if (! bytes) |
74 | break; |
75 | copy(substream, rec, bytes); |
76 | rec->hw_data += bytes; |
77 | if (rec->hw_data == rec->hw_buffer_size) |
78 | rec->hw_data = 0; |
79 | rec->sw_data += bytes; |
80 | if (rec->sw_data == rec->sw_buffer_size) |
81 | rec->sw_data = 0; |
82 | rec->hw_ready += bytes; |
83 | rec->sw_ready -= bytes; |
84 | } |
85 | } |
86 | |
87 | /* |
88 | * helper function for playback pointer callback |
89 | * ptr = current byte pointer |
90 | */ |
91 | static inline snd_pcm_uframes_t |
92 | snd_pcm_indirect_playback_pointer(struct snd_pcm_substream *substream, |
93 | struct snd_pcm_indirect *rec, unsigned int ptr) |
94 | { |
95 | int bytes = ptr - rec->hw_io; |
96 | if (bytes < 0) |
97 | bytes += rec->hw_buffer_size; |
98 | rec->hw_io = ptr; |
99 | rec->hw_ready -= bytes; |
100 | rec->sw_io += bytes; |
101 | if (rec->sw_io >= rec->sw_buffer_size) |
102 | rec->sw_io -= rec->sw_buffer_size; |
103 | if (substream->ops->ack) |
104 | substream->ops->ack(substream); |
105 | return bytes_to_frames(substream->runtime, rec->sw_io); |
106 | } |
107 | |
108 | |
109 | /* |
110 | * helper function for capture ack callback |
111 | */ |
112 | static inline void |
113 | snd_pcm_indirect_capture_transfer(struct snd_pcm_substream *substream, |
114 | struct snd_pcm_indirect *rec, |
115 | snd_pcm_indirect_copy_t copy) |
116 | { |
117 | struct snd_pcm_runtime *runtime = substream->runtime; |
118 | snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr; |
119 | snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr; |
120 | |
121 | if (diff) { |
122 | if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2)) |
123 | diff += runtime->boundary; |
124 | rec->sw_ready -= frames_to_bytes(runtime, diff); |
125 | rec->appl_ptr = appl_ptr; |
126 | } |
127 | while (rec->hw_ready > 0 && |
128 | rec->sw_ready < (int)rec->sw_buffer_size) { |
129 | size_t hw_to_end = rec->hw_buffer_size - rec->hw_data; |
130 | size_t sw_to_end = rec->sw_buffer_size - rec->sw_data; |
131 | size_t bytes = rec->sw_buffer_size - rec->sw_ready; |
132 | if (rec->hw_ready < (int)bytes) |
133 | bytes = rec->hw_ready; |
134 | if (hw_to_end < bytes) |
135 | bytes = hw_to_end; |
136 | if (sw_to_end < bytes) |
137 | bytes = sw_to_end; |
138 | if (! bytes) |
139 | break; |
140 | copy(substream, rec, bytes); |
141 | rec->hw_data += bytes; |
142 | if ((int)rec->hw_data == rec->hw_buffer_size) |
143 | rec->hw_data = 0; |
144 | rec->sw_data += bytes; |
145 | if (rec->sw_data == rec->sw_buffer_size) |
146 | rec->sw_data = 0; |
147 | rec->hw_ready -= bytes; |
148 | rec->sw_ready += bytes; |
149 | } |
150 | } |
151 | |
152 | /* |
153 | * helper function for capture pointer callback, |
154 | * ptr = current byte pointer |
155 | */ |
156 | static inline snd_pcm_uframes_t |
157 | snd_pcm_indirect_capture_pointer(struct snd_pcm_substream *substream, |
158 | struct snd_pcm_indirect *rec, unsigned int ptr) |
159 | { |
160 | int qsize; |
161 | int bytes = ptr - rec->hw_io; |
162 | if (bytes < 0) |
163 | bytes += rec->hw_buffer_size; |
164 | rec->hw_io = ptr; |
165 | rec->hw_ready += bytes; |
166 | qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size; |
167 | if (rec->hw_ready > qsize) |
168 | return SNDRV_PCM_POS_XRUN; |
169 | rec->sw_io += bytes; |
170 | if (rec->sw_io >= rec->sw_buffer_size) |
171 | rec->sw_io -= rec->sw_buffer_size; |
172 | if (substream->ops->ack) |
173 | substream->ops->ack(substream); |
174 | return bytes_to_frames(substream->runtime, rec->sw_io); |
175 | } |
176 | |
177 | #endif /* __SOUND_PCM_INDIRECT_H */ |
178 |
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