[PATCH 2/2] ASoC: hdmi-codec: re-introduce mutex locking again

[Jerome Brunet <jbrunet@baylibre.com>]

The dai codec needs to ensure that on one dai is used at any time.
This is currently protected by bit atomic operation. With this change,
it done with a mutex instead.

Suggested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 sound/soc/codecs/hdmi-codec.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/sound/soc/codecs/hdmi-codec.c b/sound/soc/codecs/hdmi-codec.c
index f8b5b960e597..56f6373d7927 100644
--- a/sound/soc/codecs/hdmi-codec.c
+++ b/sound/soc/codecs/hdmi-codec.c
@@ -274,7 +274,8 @@ struct hdmi_codec_priv {
 	uint8_t eld[MAX_ELD_BYTES];
 	struct snd_pcm_chmap *chmap_info;
 	unsigned int chmap_idx;
-	unsigned long busy;
+	struct mutex lock;
+	bool busy;
 	struct snd_soc_jack *jack;
 	unsigned int jack_status;
 };
@@ -390,12 +391,15 @@ static int hdmi_codec_startup(struct snd_pcm_substream *substream,
 	struct hdmi_codec_priv *hcp = snd_soc_dai_get_drvdata(dai);
 	int ret = 0;
 
-	ret = test_and_set_bit(0, &hcp->busy);
-	if (ret) {
+	mutex_lock(&hcp->lock);
+	if (hcp->busy) {
 		dev_err(dai->dev, "Only one simultaneous stream supported!\n");
+		mutex_unlock(&hcp->lock);
 		return -EINVAL;
 	}
 
+	hcp->busy = true;
+
 	if (hcp->hcd.ops->audio_startup) {
 		ret = hcp->hcd.ops->audio_startup(dai->dev->parent, hcp->hcd.data);
 		if (ret)
@@ -415,11 +419,12 @@ static int hdmi_codec_startup(struct snd_pcm_substream *substream,
 		/* Select chmap supported */
 		hdmi_codec_eld_chmap(hcp);
 	}
-	return 0;
 
 err:
-	/* Release the exclusive lock on error */
-	clear_bit(0, &hcp->busy);
+	if (ret)
+		hcp->busy = false;
+
+	mutex_unlock(&hcp->lock);
 	return ret;
 }
 
@@ -431,7 +436,9 @@ static void hdmi_codec_shutdown(struct snd_pcm_substream *substream,
 	hcp->chmap_idx = HDMI_CODEC_CHMAP_IDX_UNKNOWN;
 	hcp->hcd.ops->audio_shutdown(dai->dev->parent, hcp->hcd.data);
 
-	clear_bit(0, &hcp->busy);
+	mutex_lock(&hcp->lock);
+	hcp->busy = false;
+	mutex_unlock(&hcp->lock);
 }
 
 static int hdmi_codec_hw_params(struct snd_pcm_substream *substream,
@@ -811,6 +818,8 @@ static int hdmi_codec_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	hcp->hcd = *hcd;
+	mutex_init(&hcp->lock);
+
 	daidrv = devm_kcalloc(dev, dai_count, sizeof(*daidrv), GFP_KERNEL);
 	if (!daidrv)
 		return -ENOMEM;
-- 
2.21.0