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1/* SPDX-License-Identifier: GPL-2.0-or-later */2/*3 * Helper functions for indirect PCM data transfer4 *5 * Copyright (c) by Takashi Iwai <tiwai@suse.de>6 * Jaroslav Kysela <perex@perex.cz>7 */8 9#ifndef __SOUND_PCM_INDIRECT_H10#define __SOUND_PCM_INDIRECT_H11 12#include <sound/pcm.h>13 14struct 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 27typedef 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 callback32 */33static inline int34snd_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, 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 callback79 * ptr = current byte pointer80 */81static inline snd_pcm_uframes_t82snd_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(substream->runtime, rec->sw_io);101}102 103 104/*105 * helper function for capture ack callback106 */107static inline int108snd_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, 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 pointer153 */154static inline snd_pcm_uframes_t155snd_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(substream->runtime, rec->sw_io);178}179 180#endif /* __SOUND_PCM_INDIRECT_H */181