[alsa-devel] Applied "ASoC: hdmi-codec: re-introduce mutex locking again" to the asoc tree

[Mark Brown]

The patch

   ASoC: hdmi-codec: re-introduce mutex locking again

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-5.6

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 1442842952ccfe4178602c7a8459ac2ecb9d9e1a Mon Sep 17 00:00:00 2001
From: Jerome Brunet <jbrunet at baylibre.com>
Date: Fri, 6 Dec 2019 11:35:42 +0100
Subject: [PATCH] ASoC: hdmi-codec: re-introduce mutex locking again

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.

This change is not about functionality or efficiency. It is done with
the hope that it help maintainability in the future.

Suggested-by: Mark Brown <broonie at kernel.org>
Signed-off-by: Jerome Brunet <jbrunet at baylibre.com>
Link: https://lore.kernel.org/r/20191206103542.485224-1-jbrunet@baylibre.com
Signed-off-by: Mark Brown <broonie at kernel.org>
---
 sound/soc/codecs/hdmi-codec.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/sound/soc/codecs/hdmi-codec.c b/sound/soc/codecs/hdmi-codec.c
index f8b5b960e597..543363102d03 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;
 };
@@ -390,9 +391,10 @@ 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;
 	}
 
@@ -405,21 +407,21 @@ static int hdmi_codec_startup(struct snd_pcm_substream *substream,
 	if (hcp->hcd.ops->get_eld) {
 		ret = hcp->hcd.ops->get_eld(dai->dev->parent, hcp->hcd.data,
 					    hcp->eld, sizeof(hcp->eld));
+		if (ret)
+			goto err;
+
+		ret = snd_pcm_hw_constraint_eld(substream->runtime, hcp->eld);
+		if (ret)
+			goto err;
 
-		if (!ret) {
-			ret = snd_pcm_hw_constraint_eld(substream->runtime,
-							hcp->eld);
-			if (ret)
-				goto err;
-		}
 		/* Select chmap supported */
 		hdmi_codec_eld_chmap(hcp);
 	}
-	return 0;
+
+	hcp->busy = true;
 
 err:
-	/* Release the exclusive lock on error */
-	clear_bit(0, &hcp->busy);
+	mutex_unlock(&hcp->lock);
 	return ret;
 }
 
@@ -431,7 +433,9 @@ 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 +815,8 @@ 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;
-- 
2.20.1