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ALSA: aloop: Add support for the non-interleaved access mode

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The current version of the loopback driver supports interleaved access
mode only. This patch introduces support for the non-interleaved
access mode.

When in the interleaved mode, the 'copy_play_buf' function copies data
from the playback to the capture buffer using one memcpy call. This call
copies samples for multiple, interleaved channels.

In the non-interleaved mode we have multiple channel buffers, so we have
to perform multiple memcpy calls to copy samples channel after channel.

Add new function called 'copy_play_buf_part_n', which copies a part of
each channel buffer from playback to capture. Modify the 'copy_play_buf'
to use the corresponding memory copy function(just memcpy /
copy_play_buf_part_n) depending on the access mode.

Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230927113555.14877-1-ivan.orlov0322@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Ivan Orlov 2023-09-27 12:35:54 +01:00 • committed by Takashi Iwai
parent 8eb2194e3f
commit 462494565c
1 changed files with 28 additions and 3 deletions
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29
sound/drivers/aloop.c
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@ -158,6 +158,9 @@ struct loopback_pcm {
unsigned long last_jiffies; unsigned long last_jiffies;
/* If jiffies timer is used */ /* If jiffies timer is used */
struct timer_list timer; struct timer_list timer;
/* size of per channel buffer in case of non-interleaved access */
unsigned int channel_buf_n;
}; };
static struct platform_device *devices[SNDRV_CARDS]; static struct platform_device *devices[SNDRV_CARDS];
@ -335,7 +338,8 @@ static int loopback_check_format(struct loopback_cable *cable, int stream)
substream->runtime; substream->runtime;
check = runtime->format != cruntime->format || check = runtime->format != cruntime->format ||
runtime->rate != cruntime->rate || runtime->rate != cruntime->rate ||
runtime->channels != cruntime->channels; runtime->channels != cruntime->channels ||
runtime->access != cruntime->access;
if (!check) if (!check)
return 0; return 0;
if (stream == SNDRV_PCM_STREAM_CAPTURE) { if (stream == SNDRV_PCM_STREAM_CAPTURE) {
@ -472,6 +476,7 @@ static int loopback_prepare(struct snd_pcm_substream *substream)
dpcm->buf_pos = 0; dpcm->buf_pos = 0;
dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size);
dpcm->channel_buf_n = dpcm->pcm_buffer_size / runtime->channels;
if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
/* clear capture buffer */ /* clear capture buffer */
dpcm->silent_size = dpcm->pcm_buffer_size; dpcm->silent_size = dpcm->pcm_buffer_size;
@ -522,6 +527,22 @@ static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes)
} }
} }
static void copy_play_buf_part_n(struct loopback_pcm *play, struct loopback_pcm *capt,
unsigned int size, unsigned int src_off, unsigned int dst_off)
{
unsigned int channels = capt->substream->runtime->channels;
unsigned int size_p_ch = size / channels;
unsigned int src_off_ch = src_off / channels;
unsigned int dst_off_ch = dst_off / channels;
int i;
for (i = 0; i < channels; i++) {
memcpy(capt->substream->runtime->dma_area + capt->channel_buf_n * i + dst_off_ch,
play->substream->runtime->dma_area + play->channel_buf_n * i + src_off_ch,
size_p_ch);
}
}
static void copy_play_buf(struct loopback_pcm *play, static void copy_play_buf(struct loopback_pcm *play,
struct loopback_pcm *capt, struct loopback_pcm *capt,
unsigned int bytes) unsigned int bytes)
@ -556,6 +577,10 @@ static void copy_play_buf(struct loopback_pcm *play,
size = play->pcm_buffer_size - src_off; size = play->pcm_buffer_size - src_off;
if (dst_off + size > capt->pcm_buffer_size) if (dst_off + size > capt->pcm_buffer_size)
size = capt->pcm_buffer_size - dst_off; size = capt->pcm_buffer_size - dst_off;
if (runtime->access == SNDRV_PCM_ACCESS_RW_NONINTERLEAVED ||
runtime->access == SNDRV_PCM_ACCESS_MMAP_NONINTERLEAVED)
copy_play_buf_part_n(play, capt, size, src_off, dst_off);
else
memcpy(dst + dst_off, src + src_off, size); memcpy(dst + dst_off, src + src_off, size);
capt->silent_size = 0; capt->silent_size = 0;
bytes -= size; bytes -= size;
@ -878,7 +903,7 @@ static const struct snd_pcm_hardware loopback_pcm_hardware =
{ {
.info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |
SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
SNDRV_PCM_INFO_RESUME), SNDRV_PCM_INFO_RESUME | SNDRV_PCM_INFO_NONINTERLEAVED),
.formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE | SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE | SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |