[alsa-devel] [PATCH V2] ASoC: fsl_audmix: Add spin lock to protect tdms

[Shengjiu Wang]

Audmix support two substream, When two substream start
to run, the trigger function may be called by two substream
in same time, that the priv->tdms may be updated wrongly.

The expected priv->tdms is 0x3, but sometimes the
result is 0x2, or 0x1.

Fixes: be1df61cf06e ("ASoC: fsl: Add Audio Mixer CPU DAI driver")
Cc: <stable at vger.kernel.org>
Signed-off-by: Shengjiu Wang <shengjiu.wang at nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka at gmail.com>
---
Change in v2
-add Fixes, Cc stable, and Acked-by.

 sound/soc/fsl/fsl_audmix.c | 6 ++++++
 sound/soc/fsl/fsl_audmix.h | 1 +
 2 files changed, 7 insertions(+)

diff --git a/sound/soc/fsl/fsl_audmix.c b/sound/soc/fsl/fsl_audmix.c
index c7e4e9757dce..a1db1bce330f 100644
--- a/sound/soc/fsl/fsl_audmix.c
+++ b/sound/soc/fsl/fsl_audmix.c
@@ -286,6 +286,7 @@ static int fsl_audmix_dai_trigger(struct snd_pcm_substream *substream, int cmd,
 				  struct snd_soc_dai *dai)
 {
 	struct fsl_audmix *priv = snd_soc_dai_get_drvdata(dai);
+	unsigned long lock_flags;
 
 	/* Capture stream shall not be handled */
 	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
@@ -295,12 +296,16 @@ static int fsl_audmix_dai_trigger(struct snd_pcm_substream *substream, int cmd,
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		spin_lock_irqsave(&priv->lock, lock_flags);
 		priv->tdms |= BIT(dai->driver->id);
+		spin_unlock_irqrestore(&priv->lock, lock_flags);
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		spin_lock_irqsave(&priv->lock, lock_flags);
 		priv->tdms &= ~BIT(dai->driver->id);
+		spin_unlock_irqrestore(&priv->lock, lock_flags);
 		break;
 	default:
 		return -EINVAL;
@@ -491,6 +496,7 @@ static int fsl_audmix_probe(struct platform_device *pdev)
 		return PTR_ERR(priv->ipg_clk);
 	}
 
+	spin_lock_init(&priv->lock);
 	platform_set_drvdata(pdev, priv);
 	pm_runtime_enable(dev);
 
diff --git a/sound/soc/fsl/fsl_audmix.h b/sound/soc/fsl/fsl_audmix.h
index 7812ffec45c5..479f05695d53 100644
--- a/sound/soc/fsl/fsl_audmix.h
+++ b/sound/soc/fsl/fsl_audmix.h
@@ -96,6 +96,7 @@ struct fsl_audmix {
 	struct platform_device *pdev;
 	struct regmap *regmap;
 	struct clk *ipg_clk;
+	spinlock_t lock; /* Protect tdms */
 	u8 tdms;
 };
 
-- 
2.21.0