Commit 46249456 authored by Ivan Orlov's avatar Ivan Orlov Committed by Takashi Iwai
Browse files

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



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: default avatarIvan Orlov <ivan.orlov0322@gmail.com>
Reviewed-by: default avatarJaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230927113555.14877-1-ivan.orlov0322@gmail.com


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 8eb2194e

sound/drivers/aloop.c

+28 −3
Original line number Diff line number Diff line
@@ -158,6 +158,9 @@ struct loopback_pcm { 
	unsigned long last_jiffies;

	/* If jiffies timer is used */

	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];
@@ -335,7 +338,8 @@ static int loopback_check_format(struct loopback_cable *cable, int stream) 
							substream->runtime;

	check = runtime->format != cruntime->format ||

		runtime->rate != cruntime->rate ||

		runtime->channels != cruntime->channels;

		runtime->channels != cruntime->channels ||

		runtime->access != cruntime->access;

	if (!check)

		return 0;

	if (stream == SNDRV_PCM_STREAM_CAPTURE) {
@@ -472,6 +476,7 @@ static int loopback_prepare(struct snd_pcm_substream *substream) 


	dpcm->buf_pos = 0;

	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) {

		/* clear capture buffer */

		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,

			  struct loopback_pcm *capt,

			  unsigned int bytes)
@@ -556,6 +577,10 @@ static void copy_play_buf(struct loopback_pcm *play, 
			size = play->pcm_buffer_size - src_off;

		if (dst_off + size > capt->pcm_buffer_size)

			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);

		capt->silent_size = 0;

		bytes -= size;
@@ -878,7 +903,7 @@ static const struct snd_pcm_hardware loopback_pcm_hardware = 
{

	.info =		(SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP |

			 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 |

			 SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |

			 SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |