--- /dev/null
+/*
+ * 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 void
+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;
+ 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;
+ }
+}
+
+/*
+ * 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 void
+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;
+ 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;
+ }
+}
+
+/*
+ * 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 */
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