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