diff options
Diffstat (limited to 'include/sound/pcm-indirect.h')
| -rw-r--r-- | include/sound/pcm-indirect.h | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/include/sound/pcm-indirect.h b/include/sound/pcm-indirect.h new file mode 100644 index 000000000..98e06ea73 --- /dev/null +++ b/include/sound/pcm-indirect.h @@ -0,0 +1,180 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Helper functions for indirect PCM data transfer + * + * Copyright (c) by Takashi Iwai <tiwai@suse.de> + * Jaroslav Kysela <perex@perex.cz> + */ + +#ifndef __SOUND_PCM_INDIRECT_H +#define __SOUND_PCM_INDIRECT_H + +#include <sound/pcm.h> + +struct snd_pcm_indirect { + unsigned int hw_buffer_size; /* Byte size of hardware buffer */ + unsigned int hw_queue_size; /* Max queue size of hw buffer (0 = buffer size) */ + unsigned int hw_data; /* Offset to next dst (or src) in hw ring buffer */ + unsigned int hw_io; /* Ring buffer hw pointer */ + int hw_ready; /* Bytes ready for play (or captured) in hw ring buffer */ + unsigned int sw_buffer_size; /* Byte size of software buffer */ + unsigned int sw_data; /* Offset to next dst (or src) in sw ring buffer */ + unsigned int sw_io; /* Current software pointer in bytes */ + int sw_ready; /* Bytes ready to be transferred to/from hw */ + snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */ +}; + +typedef void (*snd_pcm_indirect_copy_t)(struct snd_pcm_substream *substream, + struct snd_pcm_indirect *rec, size_t bytes); + +/* + * helper function for playback ack callback + */ +static inline int +snd_pcm_indirect_playback_transfer(struct snd_pcm_substream *substream, + struct snd_pcm_indirect *rec, + snd_pcm_indirect_copy_t copy) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr; + snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr; + int qsize; + + if (diff) { + if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2)) + diff += runtime->boundary; + if (diff < 0) + return -EPIPE; + rec->sw_ready += (int)frames_to_bytes(runtime, diff); + rec->appl_ptr = appl_ptr; + } + qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size; + while (rec->hw_ready < qsize && rec->sw_ready > 0) { + unsigned int hw_to_end = rec->hw_buffer_size - rec->hw_data; + unsigned int sw_to_end = rec->sw_buffer_size - rec->sw_data; + unsigned int bytes = qsize - rec->hw_ready; + if (rec->sw_ready < (int)bytes) + bytes = rec->sw_ready; + if (hw_to_end < bytes) + bytes = hw_to_end; + if (sw_to_end < bytes) + bytes = sw_to_end; + if (! bytes) + break; + copy(substream, rec, bytes); + rec->hw_data += bytes; + if (rec->hw_data == rec->hw_buffer_size) + rec->hw_data = 0; + rec->sw_data += bytes; + if (rec->sw_data == rec->sw_buffer_size) + rec->sw_data = 0; + rec->hw_ready += bytes; + rec->sw_ready -= bytes; + } + return 0; +} + +/* + * helper function for playback pointer callback + * ptr = current byte pointer + */ +static inline snd_pcm_uframes_t +snd_pcm_indirect_playback_pointer(struct snd_pcm_substream *substream, + struct snd_pcm_indirect *rec, unsigned int ptr) +{ + int bytes = ptr - rec->hw_io; + int err; + + if (bytes < 0) + bytes += rec->hw_buffer_size; + rec->hw_io = ptr; + rec->hw_ready -= bytes; + rec->sw_io += bytes; + if (rec->sw_io >= rec->sw_buffer_size) + rec->sw_io -= rec->sw_buffer_size; + if (substream->ops->ack) { + err = substream->ops->ack(substream); + if (err == -EPIPE) + return SNDRV_PCM_POS_XRUN; + } + return bytes_to_frames(substream->runtime, rec->sw_io); +} + + +/* + * helper function for capture ack callback + */ +static inline int +snd_pcm_indirect_capture_transfer(struct snd_pcm_substream *substream, + struct snd_pcm_indirect *rec, + snd_pcm_indirect_copy_t copy) +{ + struct snd_pcm_runtime *runtime = substream->runtime; + snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr; + snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr; + + if (diff) { + if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2)) + diff += runtime->boundary; + if (diff < 0) + return -EPIPE; + rec->sw_ready -= frames_to_bytes(runtime, diff); + rec->appl_ptr = appl_ptr; + } + while (rec->hw_ready > 0 && + rec->sw_ready < (int)rec->sw_buffer_size) { + size_t hw_to_end = rec->hw_buffer_size - rec->hw_data; + size_t sw_to_end = rec->sw_buffer_size - rec->sw_data; + size_t bytes = rec->sw_buffer_size - rec->sw_ready; + if (rec->hw_ready < (int)bytes) + bytes = rec->hw_ready; + if (hw_to_end < bytes) + bytes = hw_to_end; + if (sw_to_end < bytes) + bytes = sw_to_end; + if (! bytes) + break; + copy(substream, rec, bytes); + rec->hw_data += bytes; + if ((int)rec->hw_data == rec->hw_buffer_size) + rec->hw_data = 0; + rec->sw_data += bytes; + if (rec->sw_data == rec->sw_buffer_size) + rec->sw_data = 0; + rec->hw_ready -= bytes; + rec->sw_ready += bytes; + } + return 0; +} + +/* + * helper function for capture pointer callback, + * ptr = current byte pointer + */ +static inline snd_pcm_uframes_t +snd_pcm_indirect_capture_pointer(struct snd_pcm_substream *substream, + struct snd_pcm_indirect *rec, unsigned int ptr) +{ + int qsize; + int bytes = ptr - rec->hw_io; + int err; + + if (bytes < 0) + bytes += rec->hw_buffer_size; + rec->hw_io = ptr; + rec->hw_ready += bytes; + qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size; + if (rec->hw_ready > qsize) + return SNDRV_PCM_POS_XRUN; + rec->sw_io += bytes; + if (rec->sw_io >= rec->sw_buffer_size) + rec->sw_io -= rec->sw_buffer_size; + if (substream->ops->ack) { + err = substream->ops->ack(substream); + if (err == -EPIPE) + return SNDRV_PCM_POS_XRUN; + } + return bytes_to_frames(substream->runtime, rec->sw_io); +} + +#endif /* __SOUND_PCM_INDIRECT_H */ |