[alsa-devel] [RFC 1/3] ASoC: dmaengine: Don't use runtime private data for dmaengine data

[Lars-Peter Clausen]

On 09/03/2012 06:59 PM, Liam Girdwood wrote:
> Use a dedicated member to store dmaengine data so that drivers can
> use private data for their own purposes.
> 

The idea was that we'll eventually get to a point where we won't need private
data for the drivers using the generic dmaengine code. But for the transitional
period there is snd_dmaengine_pcm_{set,get}_data which allows to attach driver
private data to the dmaengine pcm. For an example see how the other users of
dmaengine pcm handle this.

> Signed-off-by: Liam Girdwood <lrg at ti.com>
> Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
> ---
>  include/sound/pcm.h           |    2 ++
>  sound/soc/soc-dmaengine-pcm.c |    2 +-
>  2 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/include/sound/pcm.h b/include/sound/pcm.h
> index cdca2ab..f9e4909 100644
> --- a/include/sound/pcm.h
> +++ b/include/sound/pcm.h
> @@ -269,6 +269,7 @@ struct snd_pcm_hw_constraint_list {
>  };
>  
>  struct snd_pcm_hwptr_log;
> +struct dmaengine_pcm_runtime_data;
>  
>  struct snd_pcm_runtime {
>  	/* -- Status -- */
> @@ -345,6 +346,7 @@ struct snd_pcm_runtime {
>  	unsigned char *dma_area;	/* DMA area */
>  	dma_addr_t dma_addr;		/* physical bus address (not accessible from main CPU) */
>  	size_t dma_bytes;		/* size of DMA area */
> +	struct dmaengine_pcm_runtime_data *dmaengine_data;
>  
>  	struct snd_dma_buffer *dma_buffer_p;	/* allocated buffer */
>  
> diff --git a/sound/soc/soc-dmaengine-pcm.c b/sound/soc/soc-dmaengine-pcm.c
> index 5df529e..27fa5ad 100644
> --- a/sound/soc/soc-dmaengine-pcm.c
> +++ b/sound/soc/soc-dmaengine-pcm.c
> @@ -40,7 +40,7 @@ struct dmaengine_pcm_runtime_data {
>  static inline struct dmaengine_pcm_runtime_data *substream_to_prtd(
>  	const struct snd_pcm_substream *substream)
>  {
> -	return substream->runtime->private_data;
> +	return substream->runtime->dmaengine_data;
>  }
>  
>  /**