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170 lines
5.0 KiB
170 lines
5.0 KiB
/* SPDX-License-Identifier: GPL-2.0-or-later */ |
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/* |
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* Helper functions for indirect PCM data transfer |
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* |
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* Copyright (c) by Takashi Iwai <[email protected]> |
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* Jaroslav Kysela <[email protected]> |
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*/ |
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#ifndef __SOUND_PCM_INDIRECT_H |
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#define __SOUND_PCM_INDIRECT_H |
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#include <sound/pcm.h> |
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struct snd_pcm_indirect { |
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unsigned int hw_buffer_size; /* Byte size of hardware buffer */ |
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unsigned int hw_queue_size; /* Max queue size of hw buffer (0 = buffer size) */ |
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unsigned int hw_data; /* Offset to next dst (or src) in hw ring buffer */ |
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unsigned int hw_io; /* Ring buffer hw pointer */ |
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int hw_ready; /* Bytes ready for play (or captured) in hw ring buffer */ |
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unsigned int sw_buffer_size; /* Byte size of software buffer */ |
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unsigned int sw_data; /* Offset to next dst (or src) in sw ring buffer */ |
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unsigned int sw_io; /* Current software pointer in bytes */ |
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int sw_ready; /* Bytes ready to be transferred to/from hw */ |
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snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */ |
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}; |
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typedef void (*snd_pcm_indirect_copy_t)(struct snd_pcm_substream *substream, |
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struct snd_pcm_indirect *rec, size_t bytes); |
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/* |
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* helper function for playback ack callback |
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*/ |
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static inline int |
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snd_pcm_indirect_playback_transfer(struct snd_pcm_substream *substream, |
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struct snd_pcm_indirect *rec, |
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snd_pcm_indirect_copy_t copy) |
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{ |
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struct snd_pcm_runtime *runtime = substream->runtime; |
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snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr; |
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snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr; |
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int qsize; |
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if (diff) { |
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if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2)) |
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diff += runtime->boundary; |
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if (diff < 0) |
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return -EINVAL; |
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rec->sw_ready += (int)frames_to_bytes(runtime, diff); |
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rec->appl_ptr = appl_ptr; |
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} |
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qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size; |
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while (rec->hw_ready < qsize && rec->sw_ready > 0) { |
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unsigned int hw_to_end = rec->hw_buffer_size - rec->hw_data; |
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unsigned int sw_to_end = rec->sw_buffer_size - rec->sw_data; |
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unsigned int bytes = qsize - rec->hw_ready; |
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if (rec->sw_ready < (int)bytes) |
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bytes = rec->sw_ready; |
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if (hw_to_end < bytes) |
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bytes = hw_to_end; |
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if (sw_to_end < bytes) |
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bytes = sw_to_end; |
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if (! bytes) |
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break; |
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copy(substream, rec, bytes); |
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rec->hw_data += bytes; |
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if (rec->hw_data == rec->hw_buffer_size) |
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rec->hw_data = 0; |
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rec->sw_data += bytes; |
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if (rec->sw_data == rec->sw_buffer_size) |
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rec->sw_data = 0; |
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rec->hw_ready += bytes; |
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rec->sw_ready -= bytes; |
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} |
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return 0; |
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} |
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/* |
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* helper function for playback pointer callback |
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* ptr = current byte pointer |
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*/ |
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static inline snd_pcm_uframes_t |
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snd_pcm_indirect_playback_pointer(struct snd_pcm_substream *substream, |
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struct snd_pcm_indirect *rec, unsigned int ptr) |
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{ |
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int bytes = ptr - rec->hw_io; |
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if (bytes < 0) |
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bytes += rec->hw_buffer_size; |
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rec->hw_io = ptr; |
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rec->hw_ready -= bytes; |
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rec->sw_io += bytes; |
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if (rec->sw_io >= rec->sw_buffer_size) |
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rec->sw_io -= rec->sw_buffer_size; |
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if (substream->ops->ack) |
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substream->ops->ack(substream); |
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return bytes_to_frames(substream->runtime, rec->sw_io); |
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} |
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/* |
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* helper function for capture ack callback |
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*/ |
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static inline int |
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snd_pcm_indirect_capture_transfer(struct snd_pcm_substream *substream, |
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struct snd_pcm_indirect *rec, |
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snd_pcm_indirect_copy_t copy) |
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{ |
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struct snd_pcm_runtime *runtime = substream->runtime; |
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snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr; |
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snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr; |
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if (diff) { |
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if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2)) |
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diff += runtime->boundary; |
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if (diff < 0) |
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return -EINVAL; |
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rec->sw_ready -= frames_to_bytes(runtime, diff); |
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rec->appl_ptr = appl_ptr; |
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} |
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while (rec->hw_ready > 0 && |
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rec->sw_ready < (int)rec->sw_buffer_size) { |
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size_t hw_to_end = rec->hw_buffer_size - rec->hw_data; |
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size_t sw_to_end = rec->sw_buffer_size - rec->sw_data; |
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size_t bytes = rec->sw_buffer_size - rec->sw_ready; |
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if (rec->hw_ready < (int)bytes) |
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bytes = rec->hw_ready; |
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if (hw_to_end < bytes) |
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bytes = hw_to_end; |
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if (sw_to_end < bytes) |
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bytes = sw_to_end; |
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if (! bytes) |
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break; |
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copy(substream, rec, bytes); |
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rec->hw_data += bytes; |
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if ((int)rec->hw_data == rec->hw_buffer_size) |
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rec->hw_data = 0; |
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rec->sw_data += bytes; |
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if (rec->sw_data == rec->sw_buffer_size) |
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rec->sw_data = 0; |
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rec->hw_ready -= bytes; |
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rec->sw_ready += bytes; |
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} |
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return 0; |
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} |
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/* |
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* helper function for capture pointer callback, |
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* ptr = current byte pointer |
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*/ |
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static inline snd_pcm_uframes_t |
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snd_pcm_indirect_capture_pointer(struct snd_pcm_substream *substream, |
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struct snd_pcm_indirect *rec, unsigned int ptr) |
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{ |
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int qsize; |
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int bytes = ptr - rec->hw_io; |
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if (bytes < 0) |
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bytes += rec->hw_buffer_size; |
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rec->hw_io = ptr; |
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rec->hw_ready += bytes; |
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qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size; |
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if (rec->hw_ready > qsize) |
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return SNDRV_PCM_POS_XRUN; |
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rec->sw_io += bytes; |
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if (rec->sw_io >= rec->sw_buffer_size) |
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rec->sw_io -= rec->sw_buffer_size; |
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if (substream->ops->ack) |
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substream->ops->ack(substream); |
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return bytes_to_frames(substream->runtime, rec->sw_io); |
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} |
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#endif /* __SOUND_PCM_INDIRECT_H */
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