Buffers used in ASoC Intel Atom SST driver

[Takashi Iwai]

On Thu, 18 Aug 2022 18:03:15 +0200,
Takashi Iwai wrote:
> 
> On Thu, 18 Aug 2022 17:59:36 +0200,
> Cezary Rojewski wrote:
> > 
> > On 2022-08-18 5:42 PM, Takashi Iwai wrote:
> > > Hi,
> > > 
> > > while cleaning up / fixing the memory allocation code, I noticed that
> > > Intel SST driver is the only driver that currently uses the
> > > SNDRV_DMA_TYPE_CONTINUOUS pages for its PCM buffer.
> > > 
> > > Is there any reason not to use the standard device buffer
> > > (SNDRV_DMA_TYPE_DEV)?  i.e. the change like below.
> > 
> > 
> > Hello,
> > 
> > Does not hurt to check the change out. I'm not aware of such
> > limitation for any of Intel's AudioDSP solutions. I cannot test this
> > change though as ATOM devices are not part of my CI. Pierre, do you
> > have any devices where this change could be tested?
> > 
> > Adding Hans as he is the key intel/atom maintainer too and I'm pretty
> > sure he has few devices on his own.
> 
> Oh yeah, thanks, Hans might be able to check.
> FWIW, the patch I asked is like below.

I guess we can merge and go forward.  The changes are very likely
safe, judging from the code, as there is no evidence of DMA address
restriction there.  So I'm going to submit the full patchset for
cleanups.


thanks,

Takashi

> 
> 
> Takashi
> 
> -- 8< --
> 
> From: Takashi Iwai <tiwai at suse.de>
> Subject: [PATCH] ASoC: Intel: sst: Switch to standard device pages
> 
> Signed-off-by: Takashi Iwai <tiwai at suse.de>
> ---
>  sound/soc/intel/atom/sst-mfld-platform-pcm.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/sound/soc/intel/atom/sst-mfld-platform-pcm.c b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> index a56dd48c045f..c75616a5fd0a 100644
> --- a/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> +++ b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> @@ -676,10 +676,9 @@ static int sst_soc_pcm_new(struct snd_soc_component *component,
>  
>  	if (dai->driver->playback.channels_min ||
>  			dai->driver->capture.channels_min) {
> -		snd_pcm_set_managed_buffer_all(pcm,
> -			SNDRV_DMA_TYPE_CONTINUOUS,
> -			snd_dma_continuous_data(GFP_DMA),
> -			SST_MIN_BUFFER, SST_MAX_BUFFER);
> +		snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV,
> +					       pcm->card->dev,
> +					       SST_MIN_BUFFER, SST_MAX_BUFFER);
>  	}
>  	return 0;
>  }
> -- 
> 2.35.3
> 
>