Re: [PATCH] ASoC: meson: Use managed DMA buffer allocation

[Jerome Brunet <jbrunet@baylibre.com>]

On Fri 18 Dec 2020 at 16:45, Lars-Peter Clausen <lars@metafoo.de> wrote:

> Using a managed buffer will pre-allocate the buffer using
> snd_pcm_lib_preallocate_pages() and automatically free it when the PCM is
> destroyed.
>
> In addition it will call snd_pcm_lib_malloc_pages() before the driver's
> hw_params() callback and snd_pcm_lib_free_pages() after the driver's
> hw_free() callback.
>
> This slightly reduces the boilerplate code of the driver.
>
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
> ---
>  sound/soc/meson/aiu-fifo-i2s.c   |  1 -
>  sound/soc/meson/aiu-fifo-spdif.c |  1 -
>  sound/soc/meson/aiu-fifo.c       | 18 ++----------------
>  3 files changed, 2 insertions(+), 18 deletions(-)
>
> diff --git a/sound/soc/meson/aiu-fifo-i2s.c b/sound/soc/meson/aiu-fifo-i2s.c
> index d91b0d874342..2388a2d0b3a6 100644
> --- a/sound/soc/meson/aiu-fifo-i2s.c
> +++ b/sound/soc/meson/aiu-fifo-i2s.c
> @@ -124,7 +124,6 @@ const struct snd_soc_dai_ops aiu_fifo_i2s_dai_ops = {
>  	.trigger	= aiu_fifo_i2s_trigger,
>  	.prepare	= aiu_fifo_i2s_prepare,
>  	.hw_params	= aiu_fifo_i2s_hw_params,
> -	.hw_free	= aiu_fifo_hw_free,
>  	.startup	= aiu_fifo_startup,
>  	.shutdown	= aiu_fifo_shutdown,
>  };
> diff --git a/sound/soc/meson/aiu-fifo-spdif.c b/sound/soc/meson/aiu-fifo-spdif.c
> index 44eb6faacf44..2fb30f89bf7a 100644
> --- a/sound/soc/meson/aiu-fifo-spdif.c
> +++ b/sound/soc/meson/aiu-fifo-spdif.c
> @@ -158,7 +158,6 @@ const struct snd_soc_dai_ops aiu_fifo_spdif_dai_ops = {
>  	.trigger	= fifo_spdif_trigger,
>  	.prepare	= fifo_spdif_prepare,
>  	.hw_params	= fifo_spdif_hw_params,
> -	.hw_free	= aiu_fifo_hw_free,
>  	.startup	= aiu_fifo_startup,
>  	.shutdown	= aiu_fifo_shutdown,
>  };
> diff --git a/sound/soc/meson/aiu-fifo.c b/sound/soc/meson/aiu-fifo.c
> index aa88aae8e517..4ad23267cace 100644
> --- a/sound/soc/meson/aiu-fifo.c
> +++ b/sound/soc/meson/aiu-fifo.c
> @@ -99,11 +99,6 @@ int aiu_fifo_hw_params(struct snd_pcm_substream *substream,
>  	struct snd_soc_component *component = dai->component;
>  	struct aiu_fifo *fifo = dai->playback_dma_data;
>  	dma_addr_t end;
> -	int ret;
> -
> -	ret = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
> -	if (ret < 0)
> -		return ret;
>  
>  	/* Setup the fifo boundaries */
>  	end = runtime->dma_addr + runtime->dma_bytes - fifo->fifo_block;
> @@ -124,12 +119,6 @@ int aiu_fifo_hw_params(struct snd_pcm_substream *substream,
>  	return 0;
>  }
>  
> -int aiu_fifo_hw_free(struct snd_pcm_substream *substream,
> -		     struct snd_soc_dai *dai)
> -{
> -	return snd_pcm_lib_free_pages(substream);
> -}
> -
>  static irqreturn_t aiu_fifo_isr(int irq, void *dev_id)
>  {
>  	struct snd_pcm_substream *playback = dev_id;
> @@ -187,15 +176,12 @@ void aiu_fifo_shutdown(struct snd_pcm_substream *substream,
>  int aiu_fifo_pcm_new(struct snd_soc_pcm_runtime *rtd,
>  		     struct snd_soc_dai *dai)
>  {
> -	struct snd_pcm_substream *substream =
> -		rtd->pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
>  	struct snd_card *card = rtd->card->snd_card;
>  	struct aiu_fifo *fifo = dai->playback_dma_data;
>  	size_t size = fifo->pcm->buffer_bytes_max;
>  
> -	snd_pcm_lib_preallocate_pages(substream,
> -				      SNDRV_DMA_TYPE_DEV,
> -				      card->dev, size, size);
> +	snd_pcm_set_managed_buffer_all(rtd->pcm, SNDRV_DMA_TYPE_DEV,
> +				       card->dev, size, size);

Hi Lars-Peter,

These FIFOs only do playback so to avoid wasting memory
s/snd_pcm_set_managed_buffer_all/snd_pcm_set_managed_buffer ?

>  
>  	return 0;
>  }