[PATCH] ASoC: imx-pcm-rpmsg: Flush pending work in hw_free

[Chancel Liu]

From: Chancel Liu <chancel.liu@xxxxxxx>

imx_rpmsg_terminate_all() queues the TERMINATE message to the workqueue
and returns, while the DAI hw_free() synchronously gates the audio
clock. The two can then run concurrently, and this concurrent access to
the shared audio clock path can cause a stop failure or even hang the
system.

Flush the workqueue in a new component hw_free(), which runs before the
DAI hw_free(), so TERMINATE is fully handled before the clock is gated.
CLOSE stays the last message.

Signed-off-by: Chancel Liu <chancel.liu@xxxxxxx>
---
 sound/soc/fsl/imx-pcm-rpmsg.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/sound/soc/fsl/imx-pcm-rpmsg.c b/sound/soc/fsl/imx-pcm-rpmsg.c
index 85b7c929a28a..6a0174d6c78d 100644
--- a/sound/soc/fsl/imx-pcm-rpmsg.c
+++ b/sound/soc/fsl/imx-pcm-rpmsg.c
@@ -178,6 +178,16 @@ static int imx_rpmsg_pcm_hw_params(struct snd_soc_component *component,
 	return 0;
 }
 
+static int imx_rpmsg_pcm_hw_free(struct snd_soc_component *component,
+				 struct snd_pcm_substream *substream)
+{
+	struct rpmsg_info *info = dev_get_drvdata(component->dev);
+
+	flush_workqueue(info->rpmsg_wq);
+
+	return 0;
+}
+
 static snd_pcm_uframes_t imx_rpmsg_pcm_pointer(struct snd_soc_component *component,
 					       struct snd_pcm_substream *substream)
 {
@@ -285,9 +295,6 @@ static int imx_rpmsg_pcm_close(struct snd_soc_component *component,
 	struct rpmsg_info *info = dev_get_drvdata(component->dev);
 	struct rpmsg_msg *msg;
 
-	/* Flush work in workqueue to make TX_CLOSE is the last message */
-	flush_workqueue(info->rpmsg_wq);
-
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 		msg = &info->msg[TX_CLOSE];
 		msg->s_msg.header.cmd = TX_CLOSE;
@@ -624,6 +631,7 @@ static const struct snd_soc_component_driver imx_rpmsg_soc_component = {
 	.open		= imx_rpmsg_pcm_open,
 	.close		= imx_rpmsg_pcm_close,
 	.hw_params	= imx_rpmsg_pcm_hw_params,
+	.hw_free	= imx_rpmsg_pcm_hw_free,
 	.trigger	= imx_rpmsg_pcm_trigger,
 	.pointer	= imx_rpmsg_pcm_pointer,
 	.ack		= imx_rpmsg_pcm_ack,

---
base-commit: 8d00cfd77ffa64477129969eec8249c8cdadc9c2
change-id: 20261019-b4-imx-pcm-rpmsg-concurrent-1522959ba768

Best regards,
-- 
Chancel Liu <chancel.liu@xxxxxxx>