[alsa-devel] [PATCH 2/2] ASoC: dmaengine_pcm: add snd_dmaengine_generic_pcm_open()

[Vinod Koul]

On Fri, Mar 15, 2013 at 11:36:41AM +0800, Shawn Guo wrote:
> With generic DMA device tree binding and helper function
> dma_request_slave_channel() in place, dmaengine_pcm should support
> that in requesting DMA channel for users that support generic DMA
> device tree binding.
> 
> Add a new API snd_dmaengine_generic_pcm_open() as the variant of
> snd_dmaengine_pcm_open().  It takes DMA client struct device pointer
> and slave channel name as arguments and calls generic DMA helper
> dma_request_slave_channel() to request DMA channel from dmaengine.
NAK

This is why we have dma_request_slave_channel_compat() API. You dont need to
write two open handlers here, just pass all the arguments and if DT is set it
will allocate a channel using dma_request_slave_channel() otherwise will do
dma_request_channel which is what you need.

> 
> Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
> Cc: Mark Brown <broonie at opensource.wolfsonmicro.com>
> Cc: alsa-devel at alsa-project.org
> Reviewed-by: Arnd Bergmann <arnd at arndb.de>
> ---
>  include/sound/dmaengine_pcm.h |    2 ++
>  sound/soc/soc-dmaengine-pcm.c |   39 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 41 insertions(+)
> 
> diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h
> index b877334..452df15 100644
> --- a/include/sound/dmaengine_pcm.h
> +++ b/include/sound/dmaengine_pcm.h
> @@ -43,6 +43,8 @@ snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream
>  
>  int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
>  	dma_filter_fn filter_fn, void *filter_data);
> +int snd_dmaengine_generic_pcm_open(struct snd_pcm_substream *substream,
> +				   struct device *dev, const char *name);
>  int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream);
>  
>  struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream);
> diff --git a/sound/soc/soc-dmaengine-pcm.c b/sound/soc/soc-dmaengine-pcm.c
> index 111b7d92..970eb2b 100644
> --- a/sound/soc/soc-dmaengine-pcm.c
> +++ b/sound/soc/soc-dmaengine-pcm.c
> @@ -304,6 +304,45 @@ int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
>  EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);
>  
>  /**
> + * snd_dmaengine_generic_pcm_open - Open a dmaengine based PCM substream
> + * @substream: PCM substream
> + * @dev: pointer to DMA client device structure
> + * @name: DMA slave channel name
> + *
> + * Returns 0 on success, a negative error code otherwise.
> + *
> + * This function is a variant of snd_dmaengine_pcm_open(). It takes different
> + * parameters and calls generic DMA helper dma_request_slave_channel() to
> + * request a DMA channel from dmaengine.
> + */
> +int snd_dmaengine_generic_pcm_open(struct snd_pcm_substream *substream,
> +				   struct device *dev, const char *name)
> +{
> +	struct dmaengine_pcm_runtime_data *prtd;
> +	int ret;
> +
> +	ret = snd_pcm_hw_constraint_integer(substream->runtime,
> +					    SNDRV_PCM_HW_PARAM_PERIODS);
> +	if (ret < 0)
> +		return ret;
> +
> +	prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
> +	if (!prtd)
> +		return -ENOMEM;
> +
> +	prtd->dma_chan = dma_request_slave_channel(dev, name);
> +	if (!prtd->dma_chan) {
> +		kfree(prtd);
> +		return -ENXIO;
> +	}
> +
> +	substream->runtime->private_data = prtd;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(snd_dmaengine_generic_pcm_open);
> +
> +/**
>   * snd_dmaengine_pcm_close - Close a dmaengine based PCM substream
>   * @substream: PCM substream
>   */
> -- 
> 1.7.9.5
> 
>