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

[Jerome Brunet]

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 <broo...@kernel.org>
Signed-off-by: Jerome Brunet <jbru...@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