Add ability to route audio between audio paths

Configfs interface for adding 'routes' is added, and allows two audio paths to chain together particular inputs/outputs, allowing for multistage audio driver handling.

A particular use-case is that of an ADSP driver. We can feed in audio to it, and capture the processed, and/or mixed, audio at it's output, and direct to another audio path driver, such as the UNICENS audio driver.

Signed-off-by: Mark Farrugia <mark.farrugia@fiberdyne.com.au>

1 files changed, 20 insertions, 1 deletions

diff --git a/sound/avirt.h b/sound/avirt.h
index cb9a61e..138d0ca 100644
--- a/sound/avirt.h
+++ b/sound/avirt.h
@@ -36,9 +36,12 @@ struct snd_avirt_stream_array; /* Forward declaration */
 typedef int (*snd_avirt_audiopath_configure)(
 	struct snd_card *card, struct snd_avirt_stream_array *stream_array);
 
+typedef void (*snd_avirt_pcm_exttrigger)(void);
+
 /**
  * AVIRT Audio Path info
  */
+typedef struct snd_avirt_audiopath snd_avirt_audiopath;
 struct snd_avirt_audiopath {
 	const char *uid; /* Unique identifier */
 	const char *name; /* Pretty name */
@@ -47,8 +50,24 @@ struct snd_avirt_audiopath {
 	const struct snd_pcm_ops *pcm_playback_ops; /* ALSA PCM playback ops */
 	const struct snd_pcm_ops *pcm_capture_ops; /* ALSA PCM capture ops */
 	snd_avirt_audiopath_configure configure; /* Config callback function */
-
+	snd_avirt_pcm_exttrigger pcm_exttrigger;
 	void *context;
+
+	// MUST be at the end
+	struct snd_avirt_audiopath *route_from_ap;
+	struct snd_avirt_audiopath *route_to_ap;
+};
+
+/**
+ * Audio routing
+ */
+struct snd_avirt_route {
+	char name[MAX_NAME_LEN];
+	unsigned int channels;
+	unsigned int direction;
+	struct snd_avirt_audiopath *from_ap;
+	struct snd_avirt_audiopath *to_ap;
+	struct config_item item;
 };
 
 /**