Re: [PATCH 2/2] ASoC: mt8183: fix audio playback slowly after playback during bootup

[Yingjoe Chen <yingjoe.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>]

On Thu, 2019-09-12 at 17:54 +0800, Jiaxin Yu wrote:
> Before regmap_reinit_cache we must reset audio reg as default value.
> So we use reset controller unit(toprgu) to reset audio hw.
> 
> Signed-off-by: Jiaxin Yu <jiaxin.yu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> ---
>  sound/soc/mediatek/common/mtk-base-afe.h   |  1 +
>  sound/soc/mediatek/mt8183/mt8183-afe-pcm.c | 21 +++++++++++++++++++++
>  sound/soc/mediatek/mt8183/mt8183-reg.h     |  6 ++++++
>  3 files changed, 28 insertions(+)
> 
> diff --git a/sound/soc/mediatek/common/mtk-base-afe.h b/sound/soc/mediatek/common/mtk-base-afe.h
> index 60cb609a9790..bccc079ee660 100644
> --- a/sound/soc/mediatek/common/mtk-base-afe.h
> +++ b/sound/soc/mediatek/common/mtk-base-afe.h
> @@ -60,6 +60,7 @@ struct mtk_base_afe {
>  	void __iomem *base_addr;
>  	struct device *dev;
>  	struct regmap *regmap;
> +	struct regmap *toprgu_regmap;
>  	struct mutex irq_alloc_lock; /* dynamic alloc irq lock */
>  
>  	unsigned int const *reg_back_up_list;
> diff --git a/sound/soc/mediatek/mt8183/mt8183-afe-pcm.c b/sound/soc/mediatek/mt8183/mt8183-afe-pcm.c
> index 4a31106d3471..0e5634b3a8e3 100644
> --- a/sound/soc/mediatek/mt8183/mt8183-afe-pcm.c
> +++ b/sound/soc/mediatek/mt8183/mt8183-afe-pcm.c
> @@ -1089,6 +1089,7 @@ static int mt8183_afe_pcm_dev_probe(struct platform_device *pdev)
>  	struct mtk_base_afe *afe;
>  	struct mt8183_afe_private *afe_priv;
>  	struct device *dev;
> +	unsigned int reg_value;
>  	int i, irq_id, ret;
>  
>  	afe = devm_kzalloc(&pdev->dev, sizeof(*afe), GFP_KERNEL);
> @@ -1126,6 +1127,26 @@ static int mt8183_afe_pcm_dev_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> +	/* toprgu_regmap init */
> +	afe->toprgu_regmap = syscon_regmap_lookup_by_phandle(dev->of_node,
> +							     "mediatek,toprgu");
> +	if (IS_ERR(afe->toprgu_regmap)) {
> +		dev_err(dev, "could not get toprgu_regmap from dev\n");
> +		return PTR_ERR(afe->toprgu_regmap);
> +	}
> +
> +	/* read TOPRGUWDT_SWSYSRST, the high 8bits must be zero */
> +	regmap_read(afe->toprgu_regmap, TOPRGUWDT_SWSYSRST, &reg_value);
> +
> +	/* write TOPRGUWDT_SWSYSRST, we need set high 8bits as 0x88 first */
> +	reg_value |= 0x88000000;
> +
> +	/* reset audio domain registers */
> +	reg_value |= 1 << AUDIO_RST_SFT;
> +	regmap_write(afe->toprgu_regmap, TOPRGUWDT_SWSYSRST, reg_value);
> +	reg_value &= ~(1 << AUDIO_RST_SFT);
> +	regmap_write(afe->toprgu_regmap, TOPRGUWDT_SWSYSRST, reg_value);


This register contain reset bits for many components.
If components access it directly at the same time, we might have race
condition.

Instead, watchdog driver should export this as reset controller so this
driver can access it using reset API.

Joe.C