linux-kernel - Re: [PATCH V2 2/9] ASoC: amd: ps: handle SoundWire interrupts in acp pci driver

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Date:   Mon, 22 May 2023 11:26:53 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Vijendar Mukunda <Vijendar.Mukunda@....com>, broonie@...nel.org
Cc:     alsa-devel@...a-project.org, Basavaraj.Hiregoudar@....com,
        Sunil-kumar.Dommati@....com, Mastan.Katragadda@....com,
        Arungopal.kondaveeti@....com, mario.limonciello@....com,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Syed Saba Kareem <Syed.SabaKareem@....com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2 2/9] ASoC: amd: ps: handle SoundWire interrupts in acp
 pci driver



On 5/22/23 08:31, Vijendar Mukunda wrote:
> Handle SoundWire manager related interrupts in ACP PCI driver
> interrupt handler and schedule SoundWire manager work queue for
> further processing.
> 
> Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@....com>
> ---
>  sound/soc/amd/ps/acp63.h  |  4 ++++
>  sound/soc/amd/ps/pci-ps.c | 43 ++++++++++++++++++++++++++++++++++-----
>  2 files changed, 42 insertions(+), 5 deletions(-)
> 
> diff --git a/sound/soc/amd/ps/acp63.h b/sound/soc/amd/ps/acp63.h
> index 95bb1cef900a..d296059be4f0 100644
> --- a/sound/soc/amd/ps/acp63.h
> +++ b/sound/soc/amd/ps/acp63.h
> @@ -88,6 +88,10 @@
>  /* time in ms for acp timeout */
>  #define ACP_TIMEOUT		500
>  
> +#define ACP_SDW0_STAT		BIT(21)
> +#define ACP_SDW1_STAT		BIT(2)
> +#define ACP_ERROR_IRQ		BIT(29)
> +
>  enum acp_config {
>  	ACP_CONFIG_0 = 0,
>  	ACP_CONFIG_1,
> diff --git a/sound/soc/amd/ps/pci-ps.c b/sound/soc/amd/ps/pci-ps.c
> index 02caae6968ad..26514e340a33 100644
> --- a/sound/soc/amd/ps/pci-ps.c
> +++ b/sound/soc/amd/ps/pci-ps.c
> @@ -56,6 +56,7 @@ static int acp63_reset(void __iomem *acp_base)
>  static void acp63_enable_interrupts(void __iomem *acp_base)
>  {
>  	writel(1, acp_base + ACP_EXTERNAL_INTR_ENB);
> +	writel(ACP_ERROR_IRQ, acp_base + ACP_EXTERNAL_INTR_CNTL);

you may want to comment on why you don't have a read-modify-write
approach for something that looks generic and not limited to a single
error bit?

>  }
>  
>  static void acp63_disable_interrupts(void __iomem *acp_base)
> @@ -102,23 +103,55 @@ static irqreturn_t acp63_irq_handler(int irq, void *dev_id)
>  {
>  	struct acp63_dev_data *adata;
>  	struct pdm_dev_data *ps_pdm_data;
> -	u32 val;
> +	struct amd_sdw_manager *amd_manager;
> +	u32 ext_intr_stat, ext_intr_stat1;
> +	u16 irq_flag = 0;
>  	u16 pdev_index;
>  
>  	adata = dev_id;
>  	if (!adata)
>  		return IRQ_NONE;
> +	ext_intr_stat = readl(adata->acp63_base + ACP_EXTERNAL_INTR_STAT);
> +	if (ext_intr_stat & ACP_SDW0_STAT) {
> +		writel(ACP_SDW0_STAT, adata->acp63_base + ACP_EXTERNAL_INTR_STAT);

[1]

this is confusing, if this is w1c, should this be:

writel(ext_intr_stat, adata->acp63_base + ACP_EXTERNAL_INTR_STAT);

Otherwise you may be clearing fields that have not been set?

> +		pdev_index = adata->sdw0_dev_index;
> +		amd_manager = dev_get_drvdata(&adata->pdev[pdev_index]->dev);
> +		if (amd_manager)
> +			schedule_work(&amd_manager->amd_sdw_irq_thread);
> +		irq_flag = 1;
> +	}
>  
> -	val = readl(adata->acp63_base + ACP_EXTERNAL_INTR_STAT);
> -	if (val & BIT(PDM_DMA_STAT)) {
> +	ext_intr_stat1 = readl(adata->acp63_base + ACP_EXTERNAL_INTR_STAT1);
> +	if (ext_intr_stat1 & ACP_SDW1_STAT) {
> +		writel(ACP_SDW1_STAT, adata->acp63_base + ACP_EXTERNAL_INTR_STAT1);

same comment here.

> +		pdev_index = adata->sdw1_dev_index;
> +		amd_manager = dev_get_drvdata(&adata->pdev[pdev_index]->dev);
> +		if (amd_manager)
> +			schedule_work(&amd_manager->amd_sdw_irq_thread);
> +		irq_flag = 1;
> +	}
> +
> +	if (ext_intr_stat & ACP_ERROR_IRQ) {
> +		writel(ACP_ERROR_IRQ, adata->acp63_base + ACP_EXTERNAL_INTR_STAT);

[2]

and this is even move confusing because you may end-up writing twice to
the same adata->acp63_base + ACP_EXTERNAL_INTR_STAT with [1] and [2], so
the previous write

writel(ACP_SDW0_STAT, adata->acp63_base + ACP_EXTERNAL_INTR_STAT);

may have cleared the register already.

Something looks wrong here?

> +		/* TODO: Report SoundWire Manager instance errors */
> +		writel(0, adata->acp63_base + ACP_SW0_I2S_ERROR_REASON);
> +		writel(0, adata->acp63_base + ACP_SW1_I2S_ERROR_REASON);
> +		writel(0, adata->acp63_base + ACP_ERROR_STATUS);
> +		irq_flag = 1;
> +	}
> +
> +	if (ext_intr_stat & BIT(PDM_DMA_STAT)) {
>  		pdev_index = adata->pdm_dev_index;
>  		ps_pdm_data = dev_get_drvdata(&adata->pdev[pdev_index]->dev);
>  		writel(BIT(PDM_DMA_STAT), adata->acp63_base + ACP_EXTERNAL_INTR_STAT);
>  		if (ps_pdm_data->capture_stream)
>  			snd_pcm_period_elapsed(ps_pdm_data->capture_stream);
> -		return IRQ_HANDLED;
> +		irq_flag = 1;
>  	}
> -	return IRQ_NONE;
> +	if (irq_flag)
> +		return IRQ_HANDLED;
> +	else
> +		return IRQ_NONE;
>  }
>  
>  static int sdw_amd_scan_controller(struct device *dev)