ALSA: virtio: PCM substream operators

Introduce the operators required for the operation of substreams.
Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com>
Link: https://lore.kernel.org/r/20210302164709.3142702-7-anton.yakovlev@opensynergy.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/virtio/Makefile

@@ -6,5 +6,6 @@ virtio_snd-objs := \
 	virtio_card.o \
 	virtio_ctl_msg.o \
 	virtio_pcm.o \
-	virtio_pcm_msg.o
+	virtio_pcm_msg.o \
+	virtio_pcm_ops.o
 

sound/virtio/virtio_pcm.c

@@ -470,6 +470,8 @@ int virtsnd_pcm_build_devs(struct virtio_snd *snd)
 
 			for (kss = ks->substream; kss; kss = kss->next)
 				vs->substreams[kss->number]->substream = kss;
+
+			snd_pcm_set_ops(vpcm->pcm, i, &virtsnd_pcm_ops);
 		}
 
 		snd_pcm_set_managed_buffer_all(vpcm->pcm,

sound/virtio/virtio_pcm.h

@@ -29,6 +29,8 @@ struct virtio_pcm_msg;
  * @hw_ptr: Substream hardware pointer value in bytes [0 ... buffer_bytes).
  * @xfer_enabled: Data transfer state (0 - off, 1 - on).
  * @xfer_xrun: Data underflow/overflow state (0 - no xrun, 1 - xrun).
+ * @stopped: True if the substream is stopped and must be released on the device
+ *           side.
  * @msgs: Allocated I/O messages.
  * @nmsgs: Number of allocated I/O messages.
  * @msg_last_enqueued: Index of the last I/O message added to the virtqueue.
@@ -49,6 +51,7 @@ struct virtio_pcm_substream {
 	size_t hw_ptr;
 	bool xfer_enabled;
 	bool xfer_xrun;
+	bool stopped;
 	struct virtio_pcm_msg **msgs;
 	unsigned int nmsgs;
 	int msg_last_enqueued;
@@ -80,6 +83,8 @@ struct virtio_pcm {
 	struct virtio_pcm_stream streams[SNDRV_PCM_STREAM_LAST + 1];
 };
 
+extern const struct snd_pcm_ops virtsnd_pcm_ops;
+
 int virtsnd_pcm_validate(struct virtio_device *vdev);
 
 int virtsnd_pcm_parse_cfg(struct virtio_snd *snd);