ASoC: SOF: trace: Introduce SOF_DTRACE_INITIALIZING state

With the new state we can make sure we are not missing the first
host_offset update.

In case the dtrace is small, the DMA copy will be fast and depending on
the moonphase it might be done before we set the sdev->dtrace_state  to
SOF_DTRACE_ENABLED.

The DMA will start the copy as soon as the host starts the DMA. Set the
dtrace to enabled before we let the DMA to run in order to avoid missing
the position update.

The new state is needed to cover architectures where the host side
snd_sof_dma_trace_trigger() is a NOP and the dtrace in the firmware is
ready as soon as the IPC message has been processed.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

Author: ujfalusi

sound/soc/sof/sof-priv.h

@@ -446,6 +446,7 @@ struct snd_sof_ipc {
 enum sof_dtrace_state {
 	SOF_DTRACE_DISABLED,
 	SOF_DTRACE_STOPPED,
+	SOF_DTRACE_INITIALIZING,
 	SOF_DTRACE_ENABLED,
 };
 

sound/soc/sof/trace.c

@@ -429,6 +429,7 @@ static int snd_sof_enable_trace(struct snd_sof_dev *sdev)
 	dev_dbg(sdev->dev, "%s: stream_tag: %d\n", __func__, params.stream_tag);
 
 	/* send IPC to the DSP */
+	sdev->dtrace_state = SOF_DTRACE_INITIALIZING;
 	ret = sof_ipc_tx_message(sdev->ipc, &params, sizeof(params), &ipc_reply, sizeof(ipc_reply));
 	if (ret < 0) {
 		dev_err(sdev->dev,
@@ -437,15 +438,15 @@ static int snd_sof_enable_trace(struct snd_sof_dev *sdev)
 	}
 
 start:
+	sdev->dtrace_state = SOF_DTRACE_ENABLED;
+
 	ret = snd_sof_dma_trace_trigger(sdev, SNDRV_PCM_TRIGGER_START);
 	if (ret < 0) {
 		dev_err(sdev->dev,
 			"error: snd_sof_dma_trace_trigger: start: %d\n", ret);
 		goto trace_release;
 	}
 
-	sdev->dtrace_state = SOF_DTRACE_ENABLED;
-
 	return 0;
 
 trace_release:
@@ -524,7 +525,8 @@ int snd_sof_trace_update_pos(struct snd_sof_dev *sdev,
 	if (!sdev->dtrace_is_supported)
 		return 0;
 
-	if (sdev->dtrace_state == SOF_DTRACE_ENABLED &&
+	if ((sdev->dtrace_state == SOF_DTRACE_ENABLED ||
+	     sdev->dtrace_state == SOF_DTRACE_INITIALIZING) &&
 	    sdev->host_offset != posn->host_offset) {
 		sdev->host_offset = posn->host_offset;
 		wake_up(&sdev->trace_sleep);