[PATCH v3] ASoC: qcom: Fix for DMA interrupt clear reg overwriting

[Marek Szyprowski]

Hi,

On 09.06.2021 09:23, Srinivasa Rao Mandadapu wrote:
> The DMA interrupt clear register overwritten during
> simultaneous playback and capture in lpass platform
> interrupt handler. It's causing playback or capture stuck
> in similtaneous plaback on speaker and capture on dmic test.
> Update appropriate reg fields of corresponding channel instead
> of entire register write.
>
> Fixes: commit c5c8635a04711 ("ASoC: qcom: Add LPASS platform driver")
>
> Signed-off-by: Srinivasa Rao Mandadapu <srivasam at codeaurora.org>

This patch landed recently in linux-next as commit da0363f7bfd3 ("ASoC: 
qcom: Fix for DMA interrupt clear reg overwriting"). It breaks ALSA 
playback on DragonBoard 410c (arch/arm64/boot/dts/qcom/apq8016-sbc.dts). 
After applying this patch, running 'speaker-test -l1' never finishes. 
There is no error nor kernel warning message. Before that commit, the 
playback worked fine on that board.

> ---
> Changes since v2:
> 	-- Removed redundant variables.
> Changes since v1:
> 	-- Subject lines changed.
>   sound/soc/qcom/lpass-platform.c | 12 ++++++------
>   1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/sound/soc/qcom/lpass-platform.c b/sound/soc/qcom/lpass-platform.c
> index 0df9481ea4c6..f9df76d37858 100644
> --- a/sound/soc/qcom/lpass-platform.c
> +++ b/sound/soc/qcom/lpass-platform.c
> @@ -526,7 +526,7 @@ static int lpass_platform_pcmops_trigger(struct snd_soc_component *component,
>   			return -EINVAL;
>   		}
>   
> -		ret = regmap_write(map, reg_irqclr, val_irqclr);
> +		ret = regmap_update_bits(map, reg_irqclr, val_irqclr, val_irqclr);
>   		if (ret) {
>   			dev_err(soc_runtime->dev, "error writing to irqclear reg: %d\n", ret);
>   			return ret;
> @@ -650,10 +650,11 @@ static irqreturn_t lpass_dma_interrupt_handler(
>   	struct lpass_variant *v = drvdata->variant;
>   	irqreturn_t ret = IRQ_NONE;
>   	int rv;
> -	unsigned int reg = 0, val = 0;
> +	unsigned int reg, val, mask;
>   	struct regmap *map;
>   	unsigned int dai_id = cpu_dai->driver->id;
>   
> +	mask = LPAIF_IRQ_ALL(chan);
>   	switch (dai_id) {
>   	case LPASS_DP_RX:
>   		map = drvdata->hdmiif_map;
> @@ -676,8 +677,7 @@ static irqreturn_t lpass_dma_interrupt_handler(
>   	return -EINVAL;
>   	}
>   	if (interrupts & LPAIF_IRQ_PER(chan)) {
> -
> -		rv = regmap_write(map, reg, LPAIF_IRQ_PER(chan) | val);
> +		rv = regmap_update_bits(map, reg, mask, (LPAIF_IRQ_PER(chan) | val));
>   		if (rv) {
>   			dev_err(soc_runtime->dev,
>   				"error writing to irqclear reg: %d\n", rv);
> @@ -688,7 +688,7 @@ static irqreturn_t lpass_dma_interrupt_handler(
>   	}
>   
>   	if (interrupts & LPAIF_IRQ_XRUN(chan)) {
> -		rv = regmap_write(map, reg, LPAIF_IRQ_XRUN(chan) | val);
> +		rv = regmap_update_bits(map, reg, mask, (LPAIF_IRQ_XRUN(chan) | val));
>   		if (rv) {
>   			dev_err(soc_runtime->dev,
>   				"error writing to irqclear reg: %d\n", rv);
> @@ -700,7 +700,7 @@ static irqreturn_t lpass_dma_interrupt_handler(
>   	}
>   
>   	if (interrupts & LPAIF_IRQ_ERR(chan)) {
> -		rv = regmap_write(map, reg, LPAIF_IRQ_ERR(chan) | val);
> +		rv = regmap_update_bits(map, reg, mask, (LPAIF_IRQ_ERR(chan) | val));
>   		if (rv) {
>   			dev_err(soc_runtime->dev,
>   				"error writing to irqclear reg: %d\n", rv);

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland