ASoC: SOF: Intel: hda: reserve host DMA channel for hostless streams

Due to the HW programming sequence requirement that the host
and link DMA channels need to be coupled/decoupled during pcm
hw_params, the host DMA channel corresponding to the link
DMA channel in use for hostless streams needs to be reserved.
This is achieved by adding a host_reserved flag in the
sof_intel_hda_stream structure which is checked when assigning
a host DMA channel.

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>

1 files changed, 9 insertions, 1 deletions

diff --git a/sound/soc/sof/intel/hda-stream.c b/sound/soc/sof/intel/hda-stream.c
index 1cd94e7631a8..a3f7c91469ec 100644
--- a/sound/soc/sof/intel/hda-stream.c
+++ b/sound/soc/sof/intel/hda-stream.c
@@ -155,6 +155,7 @@ struct hdac_ext_stream *
 hda_dsp_stream_get(struct snd_sof_dev *sdev, int direction)
 {
 	struct hdac_bus *bus = sof_to_bus(sdev);
+	struct sof_intel_hda_stream *hda_stream;
 	struct hdac_ext_stream *stream = NULL;
 	struct hdac_stream *s;
 
@@ -163,8 +164,15 @@ hda_dsp_stream_get(struct snd_sof_dev *sdev, int direction)
 	/* get an unused stream */
 	list_for_each_entry(s, &bus->stream_list, list) {
 		if (s->direction == direction && !s->opened) {
-			s->opened = true;
 			stream = stream_to_hdac_ext_stream(s);
+			hda_stream = container_of(stream,
+						  struct sof_intel_hda_stream,
+						  hda_stream);
+			/* check if the host DMA channel is reserved */
+			if (hda_stream->host_reserved)
+				continue;
+
+			s->opened = true;
 			break;
 		}
 	}