[PATCH] ASoC: fsl_esai: Add spin lock to protect reset and stop

[Shengjiu Wang]

xrun may happen at the end of stream, the
trigger->fsl_esai_trigger_stop maybe called in the middle of
fsl_esai_hw_reset, this may cause esai in wrong state
after stop, and there may be endless xrun interrupt.
So Add spin lock to lock these two function.

Fixes: 7ccafa2b3879 ("ASoC: fsl_esai: recover the channel swap after xrun")
Signed-off-by: Shengjiu Wang <shengjiu.w...@nxp.com>
---
 sound/soc/fsl/fsl_esai.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/sound/soc/fsl/fsl_esai.c b/sound/soc/fsl/fsl_esai.c
index 37b14c48b537..6a797648b66d 100644
--- a/sound/soc/fsl/fsl_esai.c
+++ b/sound/soc/fsl/fsl_esai.c
@@ -33,6 +33,7 @@
  * @fsysclk: system clock source to derive HCK, SCK and FS
  * @spbaclk: SPBA clock (optional, depending on SoC design)
  * @task: tasklet to handle the reset operation
+ * @lock: spin lock to handle reset and stop behavior
  * @fifo_depth: depth of tx/rx FIFO
  * @slot_width: width of each DAI slot
  * @slots: number of slots
@@ -56,6 +57,7 @@ struct fsl_esai {
        struct clk *fsysclk;
        struct clk *spbaclk;
        struct tasklet_struct task;
+       spinlock_t lock; /* Protect reset and stop */
        u32 fifo_depth;
        u32 slot_width;
        u32 slots;
@@ -676,8 +678,10 @@ static void fsl_esai_hw_reset(unsigned long arg)
 {
        struct fsl_esai *esai_priv = (struct fsl_esai *)arg;
        bool tx = true, rx = false, enabled[2];
+       unsigned long lock_flags;
        u32 tfcr, rfcr;
 
+       spin_lock_irqsave(&esai_priv->lock, lock_flags);
        /* Save the registers */
        regmap_read(esai_priv->regmap, REG_ESAI_TFCR, &tfcr);
        regmap_read(esai_priv->regmap, REG_ESAI_RFCR, &rfcr);
@@ -715,6 +719,8 @@ static void fsl_esai_hw_reset(unsigned long arg)
                fsl_esai_trigger_start(esai_priv, tx);
        if (enabled[rx])
                fsl_esai_trigger_start(esai_priv, rx);
+
+       spin_unlock_irqrestore(&esai_priv->lock, lock_flags);
 }
 
 static int fsl_esai_trigger(struct snd_pcm_substream *substream, int cmd,
@@ -722,6 +728,7 @@ static int fsl_esai_trigger(struct snd_pcm_substream 
*substream, int cmd,
 {
        struct fsl_esai *esai_priv = snd_soc_dai_get_drvdata(dai);
        bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
+       unsigned long lock_flags;
 
        esai_priv->channels[tx] = substream->runtime->channels;
 
@@ -734,7 +741,9 @@ static int fsl_esai_trigger(struct snd_pcm_substream 
*substream, int cmd,
        case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+               spin_lock_irqsave(&esai_priv->lock, lock_flags);
                fsl_esai_trigger_stop(esai_priv, tx);
+               spin_unlock_irqrestore(&esai_priv->lock, lock_flags);
                break;
        default:
                return -EINVAL;
@@ -1002,6 +1011,7 @@ static int fsl_esai_probe(struct platform_device *pdev)
 
        dev_set_drvdata(&pdev->dev, esai_priv);
 
+       spin_lock_init(&esai_priv->lock);
        ret = fsl_esai_hw_init(esai_priv);
        if (ret)
                return ret;
-- 
2.21.0