[alsa-devel] [PATCH 2/6] ASoC: omap-pcm: Request the DMA channel by name when dma_name is set for the dai

[Lars-Peter Clausen]

On 07/11/2013 12:18 PM, Peter Ujfalusi wrote:
> When booting with DT the platform_get_resource_byname() is not available to
> get the DMA resource. In this case the DAI drivers will configure the dma_name
> and omap-pcm can use this name to request the DMA channel.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>

> ---
>  sound/soc/omap/omap-pcm.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/soc/omap/omap-pcm.c b/sound/soc/omap/omap-pcm.c
> index c28e042..00168ab 100644
> --- a/sound/soc/omap/omap-pcm.c
> +++ b/sound/soc/omap/omap-pcm.c
> @@ -113,14 +113,24 @@ static int omap_pcm_open(struct snd_pcm_substream *substream)
>  {
>  	struct snd_soc_pcm_runtime *rtd = substream->private_data;
>  	struct snd_dmaengine_dai_dma_data *dma_data;
> +	int ret;
>  
>  	snd_soc_set_runtime_hwparams(substream, &omap_pcm_hardware);
>  
>  	dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
>  
> -	return snd_dmaengine_pcm_open_request_chan(substream,
> -						   omap_dma_filter_fn,
> -						   dma_data->filter_data);
> +	if (dma_data->dma_name) {

I'd prefer not having to have to add a field for a OMAP specific hack to the
generic struct. Two options which are  in my opinion better:

1) Just use filter_data in both cases and check rtd->cpu_dai->dev.of_node to
see whether to use it as the name to dma_request_slave_channel or as
filter_data for snd_dmaengine_pcm_open_request_chan.

2) Add a omap_pcm_filter_data struct which looks like this

struct omap_pcm_filter_data {
	int req;
	const char *dma_name;
}

And use that as the filter_data.


> +		struct dma_chan *chan;
> +
> +		chan = dma_request_slave_channel(rtd->cpu_dai->dev,
> +						 dma_data->dma_name);
> +		ret = snd_dmaengine_pcm_open(substream, chan);
> +	} else {
> +		ret = snd_dmaengine_pcm_open_request_chan(substream,
> +							  omap_dma_filter_fn,
> +							  dma_data->filter_data);
> +	}
> +	return ret;
>  }
>  
>  static int omap_pcm_mmap(struct snd_pcm_substream *substream,