sound/soc/pxa/pxa2xx-pcm-lib.c

Source file repositories/reference/linux-study-clean/sound/soc/pxa/pxa2xx-pcm-lib.c

File Facts

System
Linux kernel
Corpus path
sound/soc/pxa/pxa2xx-pcm-lib.c
Extension
.c
Size
5024 bytes
Lines
190
Domain
Driver Families
Bucket
sound/soc
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/dma/pxa-dma.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/dmaengine_pcm.h>

#include "pxa2xx-lib.h"

static const struct snd_pcm_hardware pxa2xx_pcm_hardware = {
	.info			= SNDRV_PCM_INFO_MMAP |
				  SNDRV_PCM_INFO_MMAP_VALID |
				  SNDRV_PCM_INFO_INTERLEAVED |
				  SNDRV_PCM_INFO_PAUSE |
				  SNDRV_PCM_INFO_RESUME,
	.formats		= SNDRV_PCM_FMTBIT_S16_LE |
				  SNDRV_PCM_FMTBIT_S24_LE |
				  SNDRV_PCM_FMTBIT_S32_LE,
	.period_bytes_min	= 32,
	.period_bytes_max	= 8192 - 32,
	.periods_min		= 1,
	.periods_max		= 256,
	.buffer_bytes_max	= 128 * 1024,
	.fifo_size		= 32,
};

static int pxa2xx_pcm_hw_params(struct snd_pcm_substream *substream,
			        struct snd_pcm_hw_params *params)
{
	struct dma_chan *chan = snd_dmaengine_pcm_get_chan(substream);
	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
	struct snd_dmaengine_dai_dma_data *dma_params;
	struct dma_slave_config config;
	int ret;

	dma_params = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);
	if (!dma_params)
		return 0;

	ret = snd_hwparams_to_dma_slave_config(substream, params, &config);
	if (ret)
		return ret;

	snd_dmaengine_pcm_set_config_from_dai_data(substream,
			snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream),
			&config);

	ret = dmaengine_slave_config(chan, &config);
	if (ret)
		return ret;

	return 0;
}

static int pxa2xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
	return snd_dmaengine_pcm_trigger(substream, cmd);
}

static snd_pcm_uframes_t
pxa2xx_pcm_pointer(struct snd_pcm_substream *substream)
{
	return snd_dmaengine_pcm_pointer(substream);
}

static int pxa2xx_pcm_prepare(struct snd_pcm_substream *substream)
{
	return 0;
}

static int pxa2xx_pcm_open(struct snd_pcm_substream *substream)
{
	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_dmaengine_dai_dma_data *dma_params;
	int ret;

	runtime->hw = pxa2xx_pcm_hardware;

	dma_params = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);
	if (!dma_params)
		return 0;

	/*

Annotation

Implementation Notes