Re: [PATCH v7 07/10] ASoC: qcom: Add QAIF PCM operations

[Mark Brown]

On Wed, Sep 23, 2026 at 12:18:27PM +0530, Harendra Gautam wrote:
> Add the PCM platform callbacks needed to use QAIF DAIs for playback
> and capture.

> +static int qaif_platform_pcmops_open(struct snd_soc_component *component,
> +				     struct snd_pcm_substream *substream)
> +{

> +	dma_mem_info->alloc_size = qaif_platform_hardware.buffer_bytes_max;
> +	dma_mem_info->vaddr = dma_alloc_coherent(component->dev,
> +						 dma_mem_info->alloc_size,
> +						 &dma_mem_info->dma_addr,
> +						 GFP_KERNEL);


snd_pcm_set_managed_buffer().

> +static int qaif_platform_copy(struct snd_soc_component *component,
> +			      struct snd_pcm_substream *substream,
> +			      int channel, unsigned long pos,
> +			      struct iov_iter *buf, unsigned long bytes)
> +{
> +	struct snd_pcm_runtime *rt = substream->runtime;
> +	size_t buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
> +	size_t channel_bytes = buffer_bytes / rt->channels;
> +	unsigned long offset;
> +	void *dma_buf;
> +	size_t copied;

If the buffers are already memory mapped why do we need a copy()
operation?

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