static int lx_pcm_hw_free(struct snd_pcm_substream *substream)
{
	struct lx6464es *chip = snd_pcm_substream_chip(substream);
	int err = 0;
	int is_capture = (substream->stream == SNDRV_PCM_STREAM_CAPTURE);

	dev_dbg(chip->card->dev, "->lx_pcm_hw_free\n");
	mutex_lock(&chip->setup_mutex);

	if (chip->hardware_running[is_capture]) {
		err = lx_hardware_stop(chip, substream);
		if (err < 0) {
			dev_err(chip->card->dev, "failed to stop hardware. "
				   "Error code %d\n", err);
			goto exit;
		}

		err = lx_hardware_close(chip, substream);
		if (err < 0) {
			dev_err(chip->card->dev, "failed to close hardware. "
				   "Error code %d\n", err);
			goto exit;
		}

		chip->hardware_running[is_capture] = 0;
	}

	err = snd_pcm_lib_free_pages(substream);

	if (is_capture)
		chip->capture_stream.stream = 0;
	else
		chip->playback_stream.stream = 0;

exit:
	mutex_unlock(&chip->setup_mutex);
	return err;
}

/* hw_free callback */
static int snd_vortex_pcm_hw_free(struct snd_pcm_substream *substream)
{
	vortex_t *chip = snd_pcm_substream_chip(substream);
	stream_t *stream = (stream_t *) (substream->runtime->private_data);

	spin_lock_irq(&chip->lock);
	// Delete audio routes.
	if (VORTEX_PCM_TYPE(substream->pcm) != VORTEX_PCM_WT) {
		if (stream != NULL)
			vortex_adb_allocroute(chip, stream->dma,
					      stream->nr_ch, stream->dir,
					      stream->type);
	}
#ifndef CHIP_AU8810
	else {
		if (stream != NULL)
			vortex_wt_allocroute(chip, stream->dma, 0);
	}
#endif
	substream->runtime->private_data = NULL;
	spin_unlock_irq(&chip->lock);

	return snd_pcm_lib_free_pages(substream);
}

static int skl_substream_free_pages(struct hdac_bus *bus,
				struct snd_pcm_substream *substream)
{
	return snd_pcm_lib_free_pages(substream);
}

static int snd_als300_pcm_hw_free(struct snd_pcm_substream *substream)
{
	return snd_pcm_lib_free_pages(substream);
}

static int bf5xx_pcm_hw_free(struct snd_pcm_substream *substream)
{
	snd_pcm_lib_free_pages(substream);

	return 0;
}

/* hw_free callback */
static int snd_p16v_pcm_hw_free_capture(struct snd_pcm_substream *substream)
{
	return snd_pcm_lib_free_pages(substream);
}

static int snd_ice1712_hw_free(struct snd_pcm_substream *substream)
{
	return snd_pcm_lib_free_pages(substream);
}

static int substream_free_pages(struct azx *chip,
				struct snd_pcm_substream *substream)
{
	return snd_pcm_lib_free_pages(substream);
}

static int sst_platform_pcm_hw_free(struct snd_pcm_substream *substream)
{
	return snd_pcm_lib_free_pages(substream);
}

static int nuc900_dma_hw_free(struct snd_pcm_substream *substream)
{
	snd_pcm_lib_free_pages(substream);
	return 0;
}

static int snd_intelmad_hw_free(struct snd_pcm_substream *substream)
{
	pr_debug("snd_intelmad_hw_free called\n");
	return snd_pcm_lib_free_pages(substream);
}

/* hw_free callback */
static int snd_bcm2835_pcm_hw_free(struct snd_pcm_substream *substream)
{
	audio_info(" .. IN\n");
	return snd_pcm_lib_free_pages(substream);
}

static int minivosc_hw_free(struct snd_pcm_substream *ss)
{
	dbg("%s", __func__);
	return snd_pcm_lib_free_pages(ss);
}

static int mtk_uldlloopback_pcm_hw_free(struct snd_pcm_substream *substream)
{
    PRINTK_AUDDRV("mtk_uldlloopback_pcm_hw_free \n");
    return snd_pcm_lib_free_pages(substream);
}

//.........这里部分代码省略.........
	if(err < 0) {
		mutex_unlock(&mgr->setup_mutex);
		return err;
	}

	/* allocate buffer */
	err = snd_pcm_lib_malloc_pages(subs, params_buffer_bytes(hw));

	if (err > 0) {
		struct mixart_bufferinfo *bufferinfo;
		int i = (chip->chip_idx * MIXART_MAX_STREAM_PER_CARD) + (stream->pcm_number * (MIXART_PLAYBACK_STREAMS+MIXART_CAPTURE_STREAMS)) + subs->number;
		if( subs->stream == SNDRV_PCM_STREAM_CAPTURE ) {
			i += MIXART_PLAYBACK_STREAMS; /* in array capture is behind playback */
		}
		
		bufferinfo = (struct mixart_bufferinfo *)chip->mgr->bufferinfo.area;
		bufferinfo[i].buffer_address = subs->runtime->dma_addr;
		bufferinfo[i].available_length = subs->runtime->dma_bytes;
		/* bufferinfo[i].buffer_id  is already defined */

		snd_printdd("snd_mixart_hw_params(pcm %d) : dma_addr(%x) dma_bytes(%x) subs-number(%d)\n", i,
				bufferinfo[i].buffer_address,
				bufferinfo[i].available_length,
				subs->number);
	}
	mutex_unlock(&mgr->setup_mutex);

	return err;
}

static int snd_mixart_hw_free(struct snd_pcm_substream *subs)
{
	struct snd_mixart *chip = snd_pcm_substream_chip(subs);
	snd_pcm_lib_free_pages(subs);
	mixart_sync_nonblock_events(chip->mgr);
	return 0;
}



/*
 *  TODO CONFIGURATION SPACE for all pcms, mono pcm must update channels_max
 */
static struct snd_pcm_hardware snd_mixart_analog_caps =
{
	.info             = ( SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
			      SNDRV_PCM_INFO_MMAP_VALID |
			      SNDRV_PCM_INFO_PAUSE),
	.formats	  = ( SNDRV_PCM_FMTBIT_U8 |
			      SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
			      SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE |
			      SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE ),
	.rates            = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
	.rate_min         = 8000,
	.rate_max         = 48000,
	.channels_min     = 1,
	.channels_max     = 2,
	.buffer_bytes_max = (32*1024),
	.period_bytes_min = 256,                  /* 256 frames U8 mono*/
	.period_bytes_max = (16*1024),
	.periods_min      = 2,
	.periods_max      = (32*1024/256),
};

static struct snd_pcm_hardware snd_mixart_digital_caps =
{

/* hw_free callback */
static int snd_p16v_pcm_hw_free_capture(struct snd_pcm_substream *substream)
{
	int result;
	result = snd_pcm_lib_free_pages(substream);
	return result;
}

static int sst_media_hw_free(struct snd_pcm_substream *substream,
		struct snd_soc_dai *dai)
{
	return snd_pcm_lib_free_pages(substream);
}

/*
 * release buffers
 */
static int snd_pmac_pcm_hw_free(struct snd_pcm_substream *subs)
{
	snd_pcm_lib_free_pages(subs);
	return 0;
}

static int snd_ps3_pcm_hw_free(struct snd_pcm_substream *substream)
{
	int ret;
	ret = snd_pcm_lib_free_pages(substream);
	return ret;
};

static int dummy_pcm_hw_free(struct snd_pcm_substream *substream)
{
	if (fake_buffer)
		return 0;
	return snd_pcm_lib_free_pages(substream);
}