Edit File: pcm-indirect.h
/* * Helper functions for indirect PCM data transfer * * Copyright (c) by Takashi Iwai <tiwai@suse.de> * Jaroslav Kysela <perex@perex.cz> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #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 -EINVAL; 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; 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) substream->ops->ack(substream); 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 -EINVAL; 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; 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) substream->ops->ack(substream); return bytes_to_frames(substream->runtime, rec->sw_io); } #endif /* __SOUND_PCM_INDIRECT_H */