2019-10-23 12:32:25

by Shengjiu Wang

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

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 <[email protected]>
---
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


2019-10-24 13:09:52

by Nicolin Chen

[permalink] [raw]
Subject: Re: [PATCH] ASoC: fsl_esai: Add spin lock to protect reset and stop

On Wed, Oct 23, 2019 at 03:29:49PM +0800, Shengjiu Wang wrote:
> 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.

What about fsl_esai_trigger_start? It touches ESAI_xFCR_xFEN bit
that is being checked in the beginning of fsl_esai_hw_reset.

Could the scenario below be possible also?

1) ESAI TX starts
2) Xrun happens to TX
3) Starting fsl_esai_hw_reset (enabled[TX] = true; enabled[RX] = false)
4) ESAI RX starts
5) Finishing fsl_esai_hw_reset (enabled[RX] is still false)

Thanks
Nicolin

> 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 <[email protected]>
> ---
> 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
>

2019-10-25 19:23:53

by Shengjiu Wang

[permalink] [raw]
Subject: Re: [PATCH] ASoC: fsl_esai: Add spin lock to protect reset and stop


Hi
>
> On Wed, Oct 23, 2019 at 03:29:49PM +0800, Shengjiu Wang wrote:
> > 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.
>
> What about fsl_esai_trigger_start? It touches ESAI_xFCR_xFEN bit that is
> being checked in the beginning of fsl_esai_hw_reset.
>
> Could the scenario below be possible also?
>
> 1) ESAI TX starts
> 2) Xrun happens to TX
> 3) Starting fsl_esai_hw_reset (enabled[TX] = true; enabled[RX] = false)
> 4) ESAI RX starts
> 5) Finishing fsl_esai_hw_reset (enabled[RX] is still false)
>
>
Good catch, this may possible. Will update in v2.

Best regards
Wang shengjiu