[PATCH 07/14] ASoC: amd: add acp3x pdm driver dma ops

[Pierre-Louis Bossart]

On 5/5/20 3:53 PM, Alex Deucher wrote:
> From: Vijendar Mukunda <Vijendar.Mukunda at amd.com>
> 
> This patch adds PDM driver DMA operations.
> 
> Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda at amd.com>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>   sound/soc/amd/renoir/acp3x-pdm-dma.c | 199 +++++++++++++++++++++++++++
>   sound/soc/amd/renoir/rn_acp3x.h      |  29 ++++
>   2 files changed, 228 insertions(+)
> 
> diff --git a/sound/soc/amd/renoir/acp3x-pdm-dma.c b/sound/soc/amd/renoir/acp3x-pdm-dma.c
> index 4ee47a85e37e..0b5dc49f42c3 100644
> --- a/sound/soc/amd/renoir/acp3x-pdm-dma.c
> +++ b/sound/soc/amd/renoir/acp3x-pdm-dma.c
> @@ -16,6 +16,25 @@
>   
>   #define DRV_NAME "acp_rn_pdm_dma"
>   
> +static const struct snd_pcm_hardware acp_pdm_hardware_capture = {
> +	.info = SNDRV_PCM_INFO_INTERLEAVED |
> +		SNDRV_PCM_INFO_BLOCK_TRANSFER |
> +		SNDRV_PCM_INFO_BATCH | SNDRV_PCM_INFO_MMAP |
> +		SNDRV_PCM_INFO_MMAP_VALID |
> +	    SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME,

Can you actually resume from the same position? this seems odd when 
combined with INFO_BATCH which means the position is only precise at 
period boundaries.

> +	.formats = SNDRV_PCM_FMTBIT_S32_LE,
> +	.channels_min = 2,
> +	.channels_max = 2,
> +	.rates = SNDRV_PCM_RATE_48000,
> +	.rate_min = 48000,
> +	.rate_max = 48000,
> +	.buffer_bytes_max = CAPTURE_MAX_NUM_PERIODS * CAPTURE_MAX_PERIOD_SIZE,
> +	.period_bytes_min = CAPTURE_MIN_PERIOD_SIZE,
> +	.period_bytes_max = CAPTURE_MAX_PERIOD_SIZE,
> +	.periods_min = CAPTURE_MIN_NUM_PERIODS,
> +	.periods_max = CAPTURE_MAX_NUM_PERIODS,
> +};
> +

[...]

> +static snd_pcm_uframes_t acp_pdm_dma_pointer(struct snd_soc_component *comp,
> +					     struct snd_pcm_substream *stream)
> +{
> +	struct pdm_stream_instance *rtd;
> +	u32 pos, buffersize;
> +	u64 bytescount;
> +
> +	rtd = stream->runtime->private_data;
> +	pos = 0;
> +	buffersize = 0;
> +	bytescount = 0;

these 3 inits seem unnecessary?
> +
> +	buffersize = frames_to_bytes(stream->runtime,
> +				     stream->runtime->buffer_size);
> +	bytescount = acp_pdm_get_byte_count(rtd, stream->stream);
> +	if (bytescount > rtd->bytescount)
> +		bytescount -= rtd->bytescount;
> +	pos = do_div(bytescount, buffersize);
> +	return bytes_to_frames(stream->runtime, pos);
> +}
> +