ASoC: fsl_audmix: Add spin lock to protect tdms

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: be1df61 ("ASoC: fsl: Add Audio Mixer CPU DAI driver")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Link: https://lore.kernel.org/r/1e706afe53fdd1fbbbc79277c48a98f8416ba873.1573458378.git.shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: <stable@vger.kernel.org>

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);
 

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;
 };