Re: [PATCH v6 01/10] ASoC: mediatek: common: modify mtk afe platform driver for mt8196

[Chen-Yu Tsai <wenst@chromium.org>]

Hi,

On Tue, Jul 8, 2025 at 7:33 PM Darren.Ye <darren.ye@mediatek.com> wrote:
>
> From: Darren Ye <darren.ye@mediatek.com>
>
> Mofify the pcm pointer interface to support 64-bit address access.

  ^ Modify

And the subject should say the same, or shorter:

    Support 64-bit addresses in PCM pointer callback

> Signed-off-by: Darren Ye <darren.ye@mediatek.com>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Tested-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
> ---
>  .../mediatek/common/mtk-afe-platform-driver.c | 47 ++++++++++++-------
>  .../mediatek/common/mtk-afe-platform-driver.h |  2 +
>  2 files changed, 33 insertions(+), 16 deletions(-)
>
> diff --git a/sound/soc/mediatek/common/mtk-afe-platform-driver.c b/sound/soc/mediatek/common/mtk-afe-platform-driver.c
> index 70fd05d5ff48..cab4ef035199 100644
> --- a/sound/soc/mediatek/common/mtk-afe-platform-driver.c
> +++ b/sound/soc/mediatek/common/mtk-afe-platform-driver.c
> @@ -86,29 +86,44 @@ snd_pcm_uframes_t mtk_afe_pcm_pointer(struct snd_soc_component *component,
>         const struct mtk_base_memif_data *memif_data = memif->data;
>         struct regmap *regmap = afe->regmap;
>         struct device *dev = afe->dev;
> -       int reg_ofs_base = memif_data->reg_ofs_base;
> -       int reg_ofs_cur = memif_data->reg_ofs_cur;
> -       unsigned int hw_ptr = 0, hw_base = 0;
> -       int ret, pcm_ptr_bytes;
> -
> -       ret = regmap_read(regmap, reg_ofs_cur, &hw_ptr);
> -       if (ret || hw_ptr == 0) {
> -               dev_err(dev, "%s hw_ptr err\n", __func__);
> -               pcm_ptr_bytes = 0;
> +       unsigned int hw_ptr_lower32 = 0, hw_ptr_upper32 = 0;
> +       unsigned int hw_base_lower32 = 0, hw_base_upper32 = 0;
> +       unsigned long long hw_ptr = 0, hw_base = 0;
> +       int ret;
> +       unsigned long long pcm_ptr_bytes = 0;
> +
> +       ret = regmap_read(regmap, memif_data->reg_ofs_cur, &hw_ptr_lower32);
> +       if (ret || hw_ptr_lower32 == 0) {

I'm not sure how the hardware is, but I think hw_ptr_lower32 == 0
should no longer be a failure, since it could be 0x100000000 or
some other address with the lower 32-bits all zero. Instead the
check should be done once the addresses are put together.

> +               dev_err(dev, "%s hw_ptr_lower32 err\n", __func__);
>                 goto POINTER_RETURN_FRAMES;

This is out of scope, but maybe this should just return zero directly
to simplify reading.

>         }
>
> -       ret = regmap_read(regmap, reg_ofs_base, &hw_base);
> -       if (ret || hw_base == 0) {
> -               dev_err(dev, "%s hw_ptr err\n", __func__);
> -               pcm_ptr_bytes = 0;
> -               goto POINTER_RETURN_FRAMES;
> +       if (memif_data->reg_ofs_cur_msb) {
> +               ret = regmap_read(regmap, memif_data->reg_ofs_cur_msb, &hw_ptr_upper32);
> +               if (ret) {
> +                       dev_err(dev, "%s hw_ptr_upper32 err\n", __func__);
> +                       goto POINTER_RETURN_FRAMES;
> +               }
>         }
>
> -       pcm_ptr_bytes = hw_ptr - hw_base;
> +       ret = regmap_read(regmap, memif_data->reg_ofs_base, &hw_base_lower32);
> +       if (ret || hw_base_lower32 == 0) {

Same here.

> +               dev_err(dev, "%s hw_base_lower32 err\n", __func__);
> +               goto POINTER_RETURN_FRAMES;
> +       }
> +       if (memif_data->reg_ofs_base_msb) {
> +               ret = regmap_read(regmap, memif_data->reg_ofs_base_msb, &hw_base_upper32);
> +               if (ret) {
> +                       dev_err(dev, "%s hw_base_upper32 err\n", __func__);
> +                       goto POINTER_RETURN_FRAMES;
> +               }
> +       }
> +       hw_ptr = ((unsigned long long)hw_ptr_upper32 << 32) + hw_ptr_lower32;
> +       hw_base = ((unsigned long long)hw_base_upper32 << 32) + hw_base_lower32;

Instead the check should be here. And to follow the original logic,
if either pointer value is zero, the function should return zero here
directly.


ChenYu

>  POINTER_RETURN_FRAMES:
> -       return bytes_to_frames(substream->runtime, pcm_ptr_bytes);
> +       pcm_ptr_bytes = MTK_ALIGN_16BYTES(hw_ptr - hw_base);
> +       return bytes_to_frames(substream->runtime, (ssize_t)pcm_ptr_bytes);
>  }
>  EXPORT_SYMBOL_GPL(mtk_afe_pcm_pointer);
>
> diff --git a/sound/soc/mediatek/common/mtk-afe-platform-driver.h b/sound/soc/mediatek/common/mtk-afe-platform-driver.h
> index fcc923b88f12..71070b26f8f8 100644
> --- a/sound/soc/mediatek/common/mtk-afe-platform-driver.h
> +++ b/sound/soc/mediatek/common/mtk-afe-platform-driver.h
> @@ -12,6 +12,8 @@
>  #define AFE_PCM_NAME "mtk-afe-pcm"
>  extern const struct snd_soc_component_driver mtk_afe_pcm_platform;
>
> +#define MTK_ALIGN_16BYTES(x) ((x) & GENMASK_ULL(39, 4))
> +
>  struct mtk_base_afe;
>  struct snd_pcm;
>  struct snd_soc_component;
> --
> 2.45.2
>
>