[alsa-devel] [PATCH v3] ASoC: davinci-mcasp: Choose PCM driver based on configured DMA controller

[Peter Ujfalusi]

On 06/02/2015 11:09 PM, Jyri Sarha wrote:
> Find the configured DMA controller by asking for a DMA channel in the
> probe phase and releasing it right after. The controller device can be
> found via the dma_chan struct and the controller is recognized from
> the compatible property of its device node. The patch assumes EDMA if
> there is no device node.

Thanks Jyri,

Acked-by: Peter Ujfalusi <peter.ujfalusi at ti.com>

> 
> Signed-off-by: Jyri Sarha <jsarha at ti.com>
> ---
> Changes since v2:
> - Print only one error message if DMA "probing" fails
>   and none in case of -EPROBE_DEFER
> 
> Changes since first patch version:
> - Change enum names from MCASP_?DMA to PCM_?DMA
> - Return PCM_EDMA if !mcasp->dev->of_node
> - Do not ignore possible error code returned by
>   davinci_mcasp_get_dma_type()
> 
>  sound/soc/davinci/davinci-mcasp.c | 70 +++++++++++++++++++++++++++++++++------
>  1 file changed, 60 insertions(+), 10 deletions(-)
> 
> diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
> index d793494..a73cd57 100644
> --- a/sound/soc/davinci/davinci-mcasp.c
> +++ b/sound/soc/davinci/davinci-mcasp.c
> @@ -1565,6 +1565,49 @@ static int davinci_mcasp_init_ch_constraints(struct davinci_mcasp *mcasp)
>  	return ret;
>  }
>  
> +enum {
> +	PCM_EDMA,
> +	PCM_SDMA,
> +};
> +static const char *sdma_prefix = "ti,omap";
> +
> +static int davinci_mcasp_get_dma_type(struct davinci_mcasp *mcasp)
> +{
> +	struct dma_chan *chan;
> +	const char *tmp;
> +	int ret = PCM_EDMA;
> +
> +	if (!mcasp->dev->of_node)
> +		return PCM_EDMA;
> +
> +	tmp = mcasp->dma_data[SNDRV_PCM_STREAM_PLAYBACK].filter_data;
> +	chan = dma_request_slave_channel_reason(mcasp->dev, tmp);
> +	if (IS_ERR(chan)) {
> +		if (PTR_ERR(chan) != -EPROBE_DEFER)
> +			dev_err(mcasp->dev,
> +				"Can't verify DMA configuration (%ld)\n",
> +				PTR_ERR(chan));
> +		return PTR_ERR(chan);
> +	}
> +	BUG_ON(!chan->device || !chan->device->dev);
> +
> +	if (chan->device->dev->of_node)
> +		ret = of_property_read_string(chan->device->dev->of_node,
> +					      "compatible", &tmp);
> +	else
> +		dev_dbg(mcasp->dev, "DMA controller has no of-node\n");
> +
> +	dma_release_channel(chan);
> +	if (ret)
> +		return ret;
> +
> +	dev_dbg(mcasp->dev, "DMA controller compatible = \"%s\"\n", tmp);
> +	if (!strncmp(tmp, sdma_prefix, strlen(sdma_prefix)))
> +		return PCM_SDMA;
> +
> +	return PCM_EDMA;
> +}
> +
>  static int davinci_mcasp_probe(struct platform_device *pdev)
>  {
>  	struct snd_dmaengine_dai_dma_data *dma_data;
> @@ -1763,27 +1806,34 @@ static int davinci_mcasp_probe(struct platform_device *pdev)
>  	if (ret != 0)
>  		goto err;
>  
> -	switch (mcasp->version) {
> +	ret = davinci_mcasp_get_dma_type(mcasp);
> +	switch (ret) {
> +	case PCM_EDMA:
>  #if IS_BUILTIN(CONFIG_SND_EDMA_SOC) || \
>  	(IS_MODULE(CONFIG_SND_DAVINCI_SOC_MCASP) && \
>  	 IS_MODULE(CONFIG_SND_EDMA_SOC))
> -	case MCASP_VERSION_1:
> -	case MCASP_VERSION_2:
> -	case MCASP_VERSION_3:
>  		ret = edma_pcm_platform_register(&pdev->dev);
> -		break;
> +#else
> +		dev_err(&pdev->dev, "Missing SND_EDMA_SOC\n");
> +		ret = -EINVAL;
> +		goto err;
>  #endif
> +		break;
> +	case PCM_SDMA:
>  #if IS_BUILTIN(CONFIG_SND_OMAP_SOC) || \
>  	(IS_MODULE(CONFIG_SND_DAVINCI_SOC_MCASP) && \
>  	 IS_MODULE(CONFIG_SND_OMAP_SOC))
> -	case MCASP_VERSION_4:
>  		ret = omap_pcm_platform_register(&pdev->dev);
> -		break;
> +#else
> +		dev_err(&pdev->dev, "Missing SND_SDMA_SOC\n");
> +		ret = -EINVAL;
> +		goto err;
>  #endif
> +		break;
>  	default:
> -		dev_err(&pdev->dev, "Invalid McASP version: %d\n",
> -			mcasp->version);
> -		ret = -EINVAL;
> +		dev_err(&pdev->dev, "No DMA controller found (%d)\n", ret);
> +	case -EPROBE_DEFER:
> +		goto err;
>  		break;
>  	}
>  
> 


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