1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
2 | /* |
3 | * Helper functions for indirect PCM data transfer |
4 | * |
5 | * Copyright (c) by Takashi Iwai <tiwai@suse.de> |
6 | * Jaroslav Kysela <perex@perex.cz> |
7 | */ |
8 | |
9 | #ifndef __SOUND_PCM_INDIRECT_H |
10 | #define __SOUND_PCM_INDIRECT_H |
11 | |
12 | #include <sound/pcm.h> |
13 | |
14 | struct snd_pcm_indirect { |
15 | unsigned int hw_buffer_size; /* Byte size of hardware buffer */ |
16 | unsigned int hw_queue_size; /* Max queue size of hw buffer (0 = buffer size) */ |
17 | unsigned int hw_data; /* Offset to next dst (or src) in hw ring buffer */ |
18 | unsigned int hw_io; /* Ring buffer hw pointer */ |
19 | int hw_ready; /* Bytes ready for play (or captured) in hw ring buffer */ |
20 | unsigned int sw_buffer_size; /* Byte size of software buffer */ |
21 | unsigned int sw_data; /* Offset to next dst (or src) in sw ring buffer */ |
22 | unsigned int sw_io; /* Current software pointer in bytes */ |
23 | int sw_ready; /* Bytes ready to be transferred to/from hw */ |
24 | snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */ |
25 | }; |
26 | |
27 | typedef void (*snd_pcm_indirect_copy_t)(struct snd_pcm_substream *substream, |
28 | struct snd_pcm_indirect *rec, size_t bytes); |
29 | |
30 | /* |
31 | * helper function for playback ack callback |
32 | */ |
33 | static inline int |
34 | snd_pcm_indirect_playback_transfer(struct snd_pcm_substream *substream, |
35 | struct snd_pcm_indirect *rec, |
36 | snd_pcm_indirect_copy_t copy) |
37 | { |
38 | struct snd_pcm_runtime *runtime = substream->runtime; |
39 | snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr; |
40 | snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr; |
41 | int qsize; |
42 | |
43 | if (diff) { |
44 | if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2)) |
45 | diff += runtime->boundary; |
46 | if (diff < 0) |
47 | return -EPIPE; |
48 | rec->sw_ready += (int)frames_to_bytes(runtime, size: diff); |
49 | rec->appl_ptr = appl_ptr; |
50 | } |
51 | qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size; |
52 | while (rec->hw_ready < qsize && rec->sw_ready > 0) { |
53 | unsigned int hw_to_end = rec->hw_buffer_size - rec->hw_data; |
54 | unsigned int sw_to_end = rec->sw_buffer_size - rec->sw_data; |
55 | unsigned int bytes = qsize - rec->hw_ready; |
56 | if (rec->sw_ready < (int)bytes) |
57 | bytes = rec->sw_ready; |
58 | if (hw_to_end < bytes) |
59 | bytes = hw_to_end; |
60 | if (sw_to_end < bytes) |
61 | bytes = sw_to_end; |
62 | if (! bytes) |
63 | break; |
64 | copy(substream, rec, bytes); |
65 | rec->hw_data += bytes; |
66 | if (rec->hw_data == rec->hw_buffer_size) |
67 | rec->hw_data = 0; |
68 | rec->sw_data += bytes; |
69 | if (rec->sw_data == rec->sw_buffer_size) |
70 | rec->sw_data = 0; |
71 | rec->hw_ready += bytes; |
72 | rec->sw_ready -= bytes; |
73 | } |
74 | return 0; |
75 | } |
76 | |
77 | /* |
78 | * helper function for playback pointer callback |
79 | * ptr = current byte pointer |
80 | */ |
81 | static inline snd_pcm_uframes_t |
82 | snd_pcm_indirect_playback_pointer(struct snd_pcm_substream *substream, |
83 | struct snd_pcm_indirect *rec, unsigned int ptr) |
84 | { |
85 | int bytes = ptr - rec->hw_io; |
86 | int err; |
87 | |
88 | if (bytes < 0) |
89 | bytes += rec->hw_buffer_size; |
90 | rec->hw_io = ptr; |
91 | rec->hw_ready -= bytes; |
92 | rec->sw_io += bytes; |
93 | if (rec->sw_io >= rec->sw_buffer_size) |
94 | rec->sw_io -= rec->sw_buffer_size; |
95 | if (substream->ops->ack) { |
96 | err = substream->ops->ack(substream); |
97 | if (err == -EPIPE) |
98 | return SNDRV_PCM_POS_XRUN; |
99 | } |
100 | return bytes_to_frames(runtime: substream->runtime, size: rec->sw_io); |
101 | } |
102 | |
103 | |
104 | /* |
105 | * helper function for capture ack callback |
106 | */ |
107 | static inline int |
108 | snd_pcm_indirect_capture_transfer(struct snd_pcm_substream *substream, |
109 | struct snd_pcm_indirect *rec, |
110 | snd_pcm_indirect_copy_t copy) |
111 | { |
112 | struct snd_pcm_runtime *runtime = substream->runtime; |
113 | snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr; |
114 | snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr; |
115 | |
116 | if (diff) { |
117 | if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2)) |
118 | diff += runtime->boundary; |
119 | if (diff < 0) |
120 | return -EPIPE; |
121 | rec->sw_ready -= frames_to_bytes(runtime, size: diff); |
122 | rec->appl_ptr = appl_ptr; |
123 | } |
124 | while (rec->hw_ready > 0 && |
125 | rec->sw_ready < (int)rec->sw_buffer_size) { |
126 | size_t hw_to_end = rec->hw_buffer_size - rec->hw_data; |
127 | size_t sw_to_end = rec->sw_buffer_size - rec->sw_data; |
128 | size_t bytes = rec->sw_buffer_size - rec->sw_ready; |
129 | if (rec->hw_ready < (int)bytes) |
130 | bytes = rec->hw_ready; |
131 | if (hw_to_end < bytes) |
132 | bytes = hw_to_end; |
133 | if (sw_to_end < bytes) |
134 | bytes = sw_to_end; |
135 | if (! bytes) |
136 | break; |
137 | copy(substream, rec, bytes); |
138 | rec->hw_data += bytes; |
139 | if ((int)rec->hw_data == rec->hw_buffer_size) |
140 | rec->hw_data = 0; |
141 | rec->sw_data += bytes; |
142 | if (rec->sw_data == rec->sw_buffer_size) |
143 | rec->sw_data = 0; |
144 | rec->hw_ready -= bytes; |
145 | rec->sw_ready += bytes; |
146 | } |
147 | return 0; |
148 | } |
149 | |
150 | /* |
151 | * helper function for capture pointer callback, |
152 | * ptr = current byte pointer |
153 | */ |
154 | static inline snd_pcm_uframes_t |
155 | snd_pcm_indirect_capture_pointer(struct snd_pcm_substream *substream, |
156 | struct snd_pcm_indirect *rec, unsigned int ptr) |
157 | { |
158 | int qsize; |
159 | int bytes = ptr - rec->hw_io; |
160 | int err; |
161 | |
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 | err = substream->ops->ack(substream); |
174 | if (err == -EPIPE) |
175 | return SNDRV_PCM_POS_XRUN; |
176 | } |
177 | return bytes_to_frames(runtime: substream->runtime, size: rec->sw_io); |
178 | } |
179 | |
180 | #endif /* __SOUND_PCM_INDIRECT_H */ |
181 | |