ASoC: SOF: Intel: hda-dai: Do not release the link DMA on STOP

The linkDMA should not be released on stop trigger since a stream re-start
might happen without closing of the stream. This leaves a short time for
other streams to 'steal' the linkDMA since it has been released.

This issue is not easy to reproduce under normal conditions as usually
after stop the stream is closed, or the same stream is restarted, but if
another stream got in between the stop and start, like this:
aplay -Dhw:0,3 -c2 -r48000 -fS32_LE /dev/zero -d 120
CTRL+z
aplay -Dhw:0,0 -c2 -r48000 -fS32_LE /dev/zero -d 120

then the link DMA channels will be mixed up, resulting firmware error or
crash.

Fixes: ab55937 ("ASoC: SOF: Intel: hda: Always clean up link DMA during stop")
Closes: thesofproject/sof#9695
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

sound/soc/sof/intel/hda-dai.c

@@ -103,8 +103,10 @@ hda_dai_get_ops(struct snd_pcm_substream *substream, struct snd_soc_dai *cpu_dai
 	return sdai->platform_private;
 }
 
-int hda_link_dma_cleanup(struct snd_pcm_substream *substream, struct hdac_ext_stream *hext_stream,
-			 struct snd_soc_dai *cpu_dai)
+static int
+hda_link_dma_cleanup(struct snd_pcm_substream *substream,
+		     struct hdac_ext_stream *hext_stream,
+		     struct snd_soc_dai *cpu_dai, bool release)
 {
 	const struct hda_dai_widget_dma_ops *ops = hda_dai_get_ops(substream, cpu_dai);
 	struct sof_intel_hda_stream *hda_stream;
@@ -128,6 +130,17 @@ int hda_link_dma_cleanup(struct snd_pcm_substream *substream, struct hdac_ext_st
 		snd_hdac_ext_bus_link_clear_stream_id(hlink, stream_tag);
 	}
 
+	if (!release) {
+		/*
+		 * Force stream reconfiguration without releasing the channel on
+		 * subsequent stream restart (without free), including LinkDMA
+		 * reset.
+		 * The stream is released via hda_dai_hw_free()
+		 */
+		hext_stream->link_prepared = 0;
+		return 0;
+	}
+
 	if (ops->release_hext_stream)
 		ops->release_hext_stream(sdev, cpu_dai, substream);
 
@@ -211,7 +224,7 @@ static int __maybe_unused hda_dai_hw_free(struct snd_pcm_substream *substream,
 	if (!hext_stream)
 		return 0;
 
-	return hda_link_dma_cleanup(substream, hext_stream, cpu_dai);
+	return hda_link_dma_cleanup(substream, hext_stream, cpu_dai, true);
 }
 
 static int __maybe_unused hda_dai_hw_params_data(struct snd_pcm_substream *substream,
@@ -304,7 +317,8 @@ static int __maybe_unused hda_dai_trigger(struct snd_pcm_substream *substream, i
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_SUSPEND:
-		ret = hda_link_dma_cleanup(substream, hext_stream, dai);
+		ret = hda_link_dma_cleanup(substream, hext_stream, dai,
+					   cmd == SNDRV_PCM_TRIGGER_STOP ? false : true);
 		if (ret < 0) {
 			dev_err(sdev->dev, "%s: failed to clean up link DMA\n", __func__);
 			return ret;
@@ -672,8 +686,7 @@ static int hda_dai_suspend(struct hdac_bus *bus)
 			}
 
 			ret = hda_link_dma_cleanup(hext_stream->link_substream,
-						   hext_stream,
-						   cpu_dai);
+						   hext_stream, cpu_dai, true);
 			if (ret < 0)
 				return ret;
 		}

sound/soc/sof/intel/hda.h

@@ -1038,8 +1038,6 @@ const struct hda_dai_widget_dma_ops *
 hda_select_dai_widget_ops(struct snd_sof_dev *sdev, struct snd_sof_widget *swidget);
 int hda_dai_config(struct snd_soc_dapm_widget *w, unsigned int flags,
 		   struct snd_sof_dai_config_data *data);
-int hda_link_dma_cleanup(struct snd_pcm_substream *substream, struct hdac_ext_stream *hext_stream,
-			 struct snd_soc_dai *cpu_dai);
 
 static inline struct snd_sof_dev *widget_to_sdev(struct snd_soc_dapm_widget *w)
 {