Rework routing system

- Add 'route' to snd_avirt_stream, remove from audio path
- Add route checking - ensure that source ap and ink ap have
compatible hw params
- Add private data support for both source and sink Audio
Paths, to ensure that the PCM can hold multiple private data(s).
- Add ability to use copy_kernel and exttriggers from AVIRT instead of from Audio Paths
- Reintroduce pcm_trigger and pcm_prepare, so that 
they may be called appropriately from AVIRT, rather
than child Audio Paths.

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

1 files changed, 77 insertions, 19 deletions

diff --git a/sound/avirt.h b/sound/avirt.h
index 8378004..ecb0a21 100644
--- a/sound/avirt.h
+++ b/sound/avirt.h
@@ -39,6 +39,34 @@ typedef int (*snd_avirt_audiopath_configure)(
 typedef void (*snd_avirt_pcm_exttrigger)(void);
 
 /**
+ * ALSA copy_kernel function type
+ * A standard PCM operation from ALSA. This is used in AVIRT to copy PCM data
+ * between Audio Paths, along given routes.
+ */
+typedef int (*snd_pcm_copy_kernel)(struct snd_pcm_substream *substream,
+				   int channel, unsigned long pos, void *buf,
+				   unsigned long bytes);
+
+/*
+ * AVIRT route source/sink enumeration types
+ */
+typedef enum snd_avirt_route_endpoint_t {
+	SND_AVIRT_ROUTE_SOURCE,
+	SND_AVIRT_ROUTE_SINK,
+} snd_avirt_route_endpoint;
+
+/**
+ * Audio routing
+ */
+struct snd_avirt_route {
+	char uid[MAX_NAME_LEN]; /* Unique identifier */
+	unsigned int channels; /* Route stream channel count */
+	unsigned int direction; /* Route stream direction */
+	struct snd_avirt_audiopath *endpoint_ap[2]; /* Source/sink */
+	struct config_item item; /* configfs item reference */
+};
+
+/**
  * AVIRT Audio Path info
  */
 typedef struct snd_avirt_audiopath snd_avirt_audiopath;
@@ -50,24 +78,8 @@ 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;
+	snd_avirt_pcm_exttrigger pcm_exttrigger; /* External trigger callback */
 	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;
 };
 
 /**
@@ -81,6 +93,7 @@ struct snd_avirt_stream {
 	unsigned int direction; /* Stream direction */
 	struct snd_pcm *pcm; /* ALSA PCM  */
 	struct snd_pcm_ops *pcm_ops; /* ALSA PCM ops */
+	struct snd_avirt_route *route; /* Associated route, if any */
 	struct config_item item; /* configfs item reference */
 };
 
@@ -101,9 +114,10 @@ typedef void (*snd_avirt_ap_private_free)(struct snd_pcm *pcm);
  * Private Data Expansion
  */
 struct snd_avirt_private_data {
+	/* Initial Audio Path in the route */
 	struct snd_avirt_audiopath *audiopath;
-	void *ap_private_data;
-
+	/* Private data for source/sink Audio Paths */
+	void *ap_private_data[2];
 	snd_avirt_ap_private_free ap_private_free;
 };
 
@@ -128,4 +142,48 @@ int snd_avirt_audiopath_deregister(struct snd_avirt_audiopath *audiopath);
  */
 struct snd_avirt_audiopath *snd_avirt_audiopath_get(const char *uid);
 
+/*
+ * snd_avirt_audiopath_set_private_data - set PCM private data for an Audio Path
+ * @ap: The Audio Path whose private data to set.
+ * @pcm: The PCM where the private data is stored.
+ * @ap_private_data: The value to set to the private data.
+ * @return: 0 on success, -1 on failure.
+ */
+int snd_avirt_audiopath_set_private_data(struct snd_avirt_audiopath *ap,
+					 struct snd_pcm *pcm,
+					 void *ap_private_data);
+
+/*
+ * snd_avirt_audiopath_get_private_data - get PCM private data for an Audio Path
+ * @ap: The Audio Path whose private data to get.
+ * @pcm: The PCM where the private data is stored.
+ * @return: The value assigned to the private data.
+ */
+void *snd_avirt_audiopath_get_private_data(struct snd_avirt_audiopath *ap,
+					   struct snd_pcm *pcm);
+
+/**
+ * snd_avirt_route_endpoint_copy - get endpoint copy function for a given
+ *                                 Audio Path's source/sink.
+ * @ap: The Audio Path whose endpoint copy function to find.
+ * @endpoint: The endpoint (SND_AVIRT_ROUTE_SOURCE or SND_AVIRT_ROUTE_SINK).
+ * @return: A snd_pcm_copy_kernel function pointer that can be used to either:
+ *          1. Source PCM data into the Audio Path, or,
+ *          2. Sink PCM data out of the Audio Path.
+ *          If no Audio Path endpoint is routed for 'endpoint', NULL is returned.
+ */
+snd_pcm_copy_kernel
+snd_avirt_route_endpoint_copy(struct snd_pcm_substream *substream,
+			      snd_avirt_route_endpoint endpoint);
+
+/**
+ * snd_avirt_route_endpoint_trigger - Trigger an Audio Path's endpoint
+ *                                    (sink/source).
+ * @uid: The Audio Path whose endpoint trigger function to call.
+ * @endpoint: The endpoint (SND_AVIRT_ROUTE_SOURCE or SND_AVIRT_ROUTE_SINK).
+ * @return: 0 on success or -1 on failure.
+ */
+int snd_avirt_route_endpoint_trigger(struct snd_pcm_substream *substream,
+				     snd_avirt_route_endpoint endpoint);
+
 #endif // __SOUND_AVIRT_H