ASoC: SOF: Intel: hda: couple host and link DMA during FE hw_free

Host and link DMA are decoupled during FE hw_params. So,
they must be coupled in hw_free if the link DMA channel
is idle.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

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

@@ -438,6 +438,26 @@ int hda_dsp_stream_hw_params(struct snd_sof_dev *sdev,
 	return ret;
 }
 
+int hda_dsp_stream_hw_free(struct snd_sof_dev *sdev,
+			   struct snd_pcm_substream *substream)
+{
+	struct hdac_stream *stream = substream->runtime->private_data;
+	struct hdac_ext_stream *link_dev = container_of(stream,
+							struct hdac_ext_stream,
+							hstream);
+	struct hdac_bus *bus = sof_to_bus(sdev);
+	u32 mask = 0x1 << stream->index;
+
+	spin_lock(&bus->reg_lock);
+	/* couple host and link DMA if link DMA channel is idle */
+	if (!link_dev->link_locked)
+		snd_sof_dsp_update_bits(sdev, HDA_DSP_PP_BAR,
+					SOF_HDA_REG_PP_PPCTL, mask, 0);
+	spin_unlock(&bus->reg_lock);
+
+	return 0;
+}
+
 irqreturn_t hda_dsp_stream_interrupt(int irq, void *context)
 {
 	struct hdac_bus *bus = context;