Introduce 'unconfigure' callback

The 'unconfigure' callback can be used to clean up the 'configured'
state of an Audio Path, for when it is desired to reset the streams,
and/or reload a different stream configuration.

To destroy the streams, we must attempt to force their PCMs
closed. Take note though, that if a PCM is being written to when
an unconfigure command is issued, system instability may occur.

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

5 files changed, 73 insertions, 5 deletions

diff --git a/configfs.c b/configfs.c
index 4f88bf8..8f2d452 100644
--- a/configfs.c
+++ b/configfs.c
@@ -285,8 +285,7 @@ static void cfg_snd_avirt_stream_release(struct config_item *item)
 	}
 
 	D_INFOK("Release stream: %s", stream->name);
-	kfree(stream->pcm_ops);
-	kfree(stream);
+	snd_avirt_stream_try_destroy(stream);
 }
 
 static void cfg_snd_avirt_route_release(struct config_item *item)
@@ -420,12 +419,12 @@ cfg_snd_avirt_stream_group_configured_store(struct config_item *item,
 
 	CHK_ERR(kstrtoul(p, 10, &tmp));
 
-	if (tmp != 1) {
-		D_ERRORK("streams can only be sealed, not unsealed!");
+	if (tmp > 1) {
+		D_ERRORK("Configure streams must be 0 or 1!");
 		return -ERANGE;
 	}
 
-	snd_avirt_streams_seal();
+	(tmp) ? snd_avirt_streams_configure() : snd_avirt_streams_unconfigure();
 
 	return count;
 }
diff --git a/core.c b/core.c
index d9e264c..c2e32c5 100644
--- a/core.c
+++ b/core.c
@@ -112,6 +112,30 @@ static struct snd_pcm *snd_avirt_pcm_create(struct snd_avirt_stream *stream)
 	return pcm;
 }
 
+void snd_avirt_stream_try_destroy(struct snd_avirt_stream *stream)
+{
+	unsigned long _flags;
+	struct snd_pcm_substream *substream =
+		stream->pcm->streams[stream->direction].substream;
+
+	snd_pcm_stream_lock_irqsave(substream, _flags);
+	if (substream->runtime) {
+		if (snd_pcm_running(substream)) {
+			if (0 !=
+			    snd_pcm_stop(substream, SNDRV_PCM_STATE_SUSPENDED))
+				D_ERRORK("Could not stop PCM '%s'",
+					 stream->name);
+		}
+	}
+	snd_pcm_stream_unlock_irqrestore(substream, _flags);
+
+	snd_device_free(core.card, stream->pcm);
+	kfree(stream->pcm_ops);
+	kfree(stream);
+
+	core.stream_count--;
+}
+
 static struct snd_avirt_route *snd_avirt_route_get(const char *uid)
 {
 	struct list_head *entry;
@@ -620,6 +644,33 @@ int snd_avirt_streams_configure(void)
 	return err;
 }
 
+int snd_avirt_streams_unconfigure(void)
+{
+	int i = 0, err = 0;
+	struct snd_avirt_audiopath_obj *ap_obj;
+	struct snd_avirt_stream_array stream_array;
+
+	if (!core.streams_configured) {
+		D_ERRORK("streams are already unconfigured!");
+		return -1;
+	}
+
+	list_for_each_entry (ap_obj, &audiopath_list, list) {
+		if (!ap_obj->path->unconfigure) {
+			D_ERRORK("Cannot do 'unconfigure' for AP: %s",
+				 ap_obj->path->uid);
+			return -EFAULT;
+		}
+
+		D_INFOK("Do 'unconfigure' for AP: %s", ap_obj->path->uid);
+		ap_obj->path->unconfigure();
+	}
+
+	core.streams_configured = false;
+
+	return 0;
+}
+
 bool snd_avirt_streams_configured(void)
 {
 	return core.streams_configured;
diff --git a/core.h b/core.h
index 6f63e8c..c39002a 100644
--- a/core.h
+++ b/core.h
@@ -81,6 +81,8 @@ void snd_avirt_audiopath_destroy_obj(struct snd_avirt_audiopath_obj *p);
  */
 int snd_avirt_streams_configure(void);
 
+int snd_avirt_streams_unconfigure(void);
+
 /**
  * snd_avirt_streams_configured - Check if streams have been configured or not
  * @return: true if configured, false otherwise
@@ -122,6 +124,8 @@ int snd_avirt_route_try_complete(struct snd_avirt_route *route);
  * @return: 0 on success, negative ERRNO on failure
  */
 int snd_avirt_stream_try_complete(struct snd_avirt_stream *stream);
+void snd_avirt_stream_try_destroy(struct snd_avirt_stream *stream);
+
 /**
  * snd_avirt_stream_set_map - Set Audio Path mapping for a given stream
  * @stream: The stream to assign the mapping to.
diff --git a/loopback/loopback.c b/loopback/loopback.c
index de0f38a..49c188d 100644
--- a/loopback/loopback.c
+++ b/loopback/loopback.c
@@ -1080,6 +1080,14 @@ static int loopbackap_configure(struct snd_card *card,
 	return 0;
 }
 
+static int loopbackap_unconfigure(void)
+{
+	mutex_destroy(&loopback->cable_lock);
+	kfree(loopback);
+
+	return 0;
+}
+
 /*******************************************************************************
  * Loopback Audio Path AVIRT registration
  ******************************************************************************/
@@ -1091,6 +1099,7 @@ static struct snd_avirt_audiopath loopbackap_module = {
 	.pcm_playback_ops = &loopbackap_pcm_ops,
 	.pcm_capture_ops = &loopbackap_pcm_ops,
 	.configure = loopbackap_configure,
+	.unconfigure = loopbackap_unconfigure,
 };
 
 static int __init alsa_card_loopback_init(void)
@@ -1108,6 +1117,8 @@ static int __init alsa_card_loopback_init(void)
 
 static void __exit alsa_card_loopback_exit(void)
 {
+	mutex_destroy(&loopback->cable_lock);
+	kfree(loopback);
 	snd_avirt_audiopath_deregister(&loopbackap_module);
 }
 
diff --git a/sound/avirt.h b/sound/avirt.h
index 9259d83..46756b3 100644
--- a/sound/avirt.h
+++ b/sound/avirt.h
@@ -36,6 +36,8 @@ 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 int (*snd_avirt_audiopath_unconfigure)(void);
+
 typedef void (*snd_avirt_pcm_exttrigger)(void);
 
 /**
@@ -79,6 +81,7 @@ 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_audiopath_unconfigure unconfigure; /* Unconfig cb function */
 	snd_avirt_pcm_exttrigger pcm_exttrigger; /* External trigger callback */
 	void *context;
 };