Unverified Commit 706e2c88 authored by Shengjiu Wang's avatar Shengjiu Wang Committed by Mark Brown
Browse files

ASoC: fsl_asrc_dma: Reuse the dma channel if available in Back-End 



The dma channel has been requested by Back-End cpu dai driver already.
If fsl_asrc_dma requests dma chan with same dma:tx symlink, then
there will be below warning with SDMA.

[   48.174236] fsl-esai-dai 2024000.esai: Cannot create DMA dma:tx symlink

So if we can reuse the dma channel of Back-End, then the issue can be
fixed.

In order to get the dma channel which is already requested in Back-End.
we use the exported two functions (snd_soc_lookup_component_nolocked
and soc_component_to_pcm). If we can get the dma channel, then reuse it,
if can't, then request a new one.

Signed-off-by: default avatarShengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: default avatarNicolin Chen <nicoleotsuka@gmail.com>
Link: https://lore.kernel.org/r/3a79f0442cb4930c633cf72145cfe95a45b9c78e.1591947428.git.shengjiu.wang@nxp.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent a9a21e1e

sound/soc/fsl/fsl_asrc_dma.c

+20 −5
Original line number Diff line number Diff line
@@ -135,6 +135,8 @@ static int fsl_asrc_dma_hw_params(struct snd_soc_component *component, 
	struct snd_dmaengine_dai_dma_data *dma_params_be = NULL;

	struct snd_pcm_runtime *runtime = substream->runtime;

	struct fsl_asrc_pair *pair = runtime->private_data;

	struct dma_chan *tmp_chan = NULL, *be_chan = NULL;

	struct snd_soc_component *component_be = NULL;

	struct fsl_asrc *asrc = pair->asrc;

	struct dma_slave_config config_fe, config_be;

	enum asrc_pair_index index = pair->index;
@@ -142,7 +144,6 @@ static int fsl_asrc_dma_hw_params(struct snd_soc_component *component, 
	int stream = substream->stream;

	struct imx_dma_data *tmp_data;

	struct snd_soc_dpcm *dpcm;

	struct dma_chan *tmp_chan;

	struct device *dev_be;

	u8 dir = tx ? OUT : IN;

	dma_cap_mask_t mask;
@@ -197,17 +198,29 @@ static int fsl_asrc_dma_hw_params(struct snd_soc_component *component, 
	dma_cap_set(DMA_SLAVE, mask);

	dma_cap_set(DMA_CYCLIC, mask);



	/*

	 * The Back-End device might have already requested a DMA channel,

	 * so try to reuse it first, and then request a new one upon NULL.

	 */

	component_be = snd_soc_lookup_component_nolocked(dev_be, SND_DMAENGINE_PCM_DRV_NAME);

	if (component_be) {

		be_chan = soc_component_to_pcm(component_be)->chan[substream->stream];

		tmp_chan = be_chan;

	}

	if (!tmp_chan)

		tmp_chan = dma_request_slave_channel(dev_be, tx ? "tx" : "rx");



	/*

	 * An EDMA DEV_TO_DEV channel is fixed and bound with DMA event of each

	 * peripheral, unlike SDMA channel that is allocated dynamically. So no

	 * need to configure dma_request and dma_request2, but get dma_chan via

	 * dma_request_slave_channel directly with dma name of Front-End device

	 * need to configure dma_request and dma_request2, but get dma_chan of

	 * Back-End device directly via dma_request_slave_channel.

	 */

	if (!asrc->use_edma) {

		/* Get DMA request of Back-End */

		tmp_chan = dma_request_slave_channel(dev_be, tx ? "tx" : "rx");

		tmp_data = tmp_chan->private;

		pair->dma_data.dma_request = tmp_data->dma_request;

		if (!be_chan)

			dma_release_channel(tmp_chan);



		/* Get DMA request of Front-End */
@@ -221,6 +234,8 @@ static int fsl_asrc_dma_hw_params(struct snd_soc_component *component, 
		pair->dma_chan[dir] =

			dma_request_channel(mask, filter, &pair->dma_data);

	} else {

		if (!be_chan)

			dma_release_channel(tmp_chan);

		pair->dma_chan[dir] =

			asrc->get_dma_channel(pair, dir);

	}

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