ASoC: SOF: Introduce optional callback to configure stream data offset

Each running audio stream's data have distinct start offset within the
stream mailbox area from/to where the host can read/write.

Instead of using the struct sof_ipc_pcm_params_reply to configure this
offset, add an optional callback which is IPC agnostic.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20220310042720.976809-5-ranjani.sridharan@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/ops.h

@@ -476,6 +476,19 @@ snd_sof_ipc_pcm_params(struct snd_sof_dev *sdev,
 	return sof_ops(sdev)->ipc_pcm_params(sdev, substream, reply);
 }
 
+/* host side configuration of the stream's data offset in stream mailbox area */
+static inline int
+snd_sof_set_stream_data_offset(struct snd_sof_dev *sdev,
+			       struct snd_pcm_substream *substream,
+			       size_t posn_offset)
+{
+	if (sof_ops(sdev) && sof_ops(sdev)->set_stream_data_offset)
+		return sof_ops(sdev)->set_stream_data_offset(sdev, substream,
+							     posn_offset);
+
+	return 0;
+}
+
 /* host stream pointer */
 static inline snd_pcm_uframes_t
 snd_sof_pcm_platform_pointer(struct snd_sof_dev *sdev,

sound/soc/sof/pcm.c

@@ -276,6 +276,14 @@ static int sof_pcm_hw_params(struct snd_soc_component *component,
 		return ret;
 	}
 
+	ret = snd_sof_set_stream_data_offset(sdev, substream,
+					     ipc_params_reply.posn_offset);
+	if (ret < 0) {
+		dev_err(component->dev, "%s: invalid stream data offset for PCM %d\n",
+			__func__, spcm->pcm.pcm_id);
+		return ret;
+	}
+
 	spcm->prepared[substream->stream] = true;
 
 	/* save pcm hw_params */

sound/soc/sof/sof-priv.h

@@ -226,6 +226,11 @@ struct snd_sof_dsp_ops {
 			      struct snd_pcm_substream *substream,
 			      const struct sof_ipc_pcm_params_reply *reply); /* mandatory */
 
+	/* host side configuration of the stream's data offset in stream mailbox area */
+	int (*set_stream_data_offset)(struct snd_sof_dev *sdev,
+				      struct snd_pcm_substream *substream,
+				      size_t posn_offset); /* optional */
+
 	/* pre/post firmware run */
 	int (*pre_fw_run)(struct snd_sof_dev *sof_dev); /* optional */
 	int (*post_fw_run)(struct snd_sof_dev *sof_dev); /* optional */