ASoC: qcom: lpass-platform: Use SNDRV_DMA_TYPE_NONCOHERENT page allocation

Replace SNDRV_DMA_TYPE_DEV by SNDRV_DMA_TYPE_NONCOHERENT for pcm
buffer allocation. We measured about 18x performance improvement
when accessing the snd_pcm_mmap() buffer from userspace.

Eg: aarch64 with internal speaker
==
SNDRV_DMA_TYPE_DEV
    frames_per_second=66.4557M/s
    max_time_per_4096_frames=106.094u
    time_per_4096_frames=61.6351us

SNDRV_DMA_TYPE_NONCOHERENT
    frames_per_second=1028.58M/s
    max_time_per_4096_frames=20.312u
    time_per_4096_frames=3.98221us

Signed-off-by: Judy Hsiao <judyhsiao@chromium.org>
Link: https://lore.kernel.org/r/20221208084200.2136311-1-judyhsiao@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/qcom/lpass-platform.c b/sound/soc/qcom/lpass-platform.c
index b41ab7a..ef5cb40 100644 (file)
--- a/sound/soc/qcom/lpass-platform.c
+++ b/sound/soc/qcom/lpass-platform.c
@@ -1181,7 +1181,7 @@ static int lpass_platform_pcm_new(struct snd_soc_component *component,
        if (is_cdc_dma_port(dai_id))
                return lpass_platform_prealloc_cdc_dma_buffer(component, pcm, dai_id);
 
-       return snd_pcm_set_fixed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV,
+       return snd_pcm_set_fixed_buffer_all(pcm, SNDRV_DMA_TYPE_NONCOHERENT,
                                            component->dev, size);
 }