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9629581258
The indirect-PCM helper codes have an implicit assumption that the appl_ptr always increases. But the PCM core may deal with the decrement of appl_ptr via rewind ioctls, and it may screw up the buffer pointer management. This patch adds the negative appl_ptr diff in transfer functions and let returning an error instead of always accepting the appl_ptr updates. The callers are usually PCM ack callbacks, and they pass the error to the upper layer accordingly. Signed-off-by: Takashi Iwai <tiwai@suse.de>
184 lines
5.7 KiB
C
184 lines
5.7 KiB
C
/*
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* Helper functions for indirect PCM data transfer
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*
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* Copyright (c) by Takashi Iwai <tiwai@suse.de>
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* Jaroslav Kysela <perex@perex.cz>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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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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