ASoC: SOF: ipc3-dtrace: 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/ipc3-dtrace.c

@@ -15,6 +15,15 @@
 #define TRACE_FILTER_ELEMENTS_PER_ENTRY 4
 #define TRACE_FILTER_MAX_CONFIG_STRING_LENGTH 1024
 
+static bool trace_pos_update_expected(struct snd_sof_dev *sdev)
+{
+	if (sdev->dtrace_state == SOF_DTRACE_ENABLED ||
+	    sdev->dtrace_state == SOF_DTRACE_INITIALIZING)
+		return true;
+
+	return false;
+}
+
 static int trace_filter_append_elem(struct snd_sof_dev *sdev, u32 key, u32 value,
 				    struct sof_ipc_trace_filter_elem *elem_list,
 				    int capacity, int *counter)
@@ -255,7 +264,7 @@ static size_t sof_wait_dtrace_avail(struct snd_sof_dev *sdev, loff_t pos,
 	if (ret)
 		return ret;
 
-	if (sdev->dtrace_state != SOF_DTRACE_ENABLED && sdev->dtrace_draining) {
+	if (sdev->dtrace_draining && !trace_pos_update_expected(sdev)) {
 		/*
 		 * tracing has ended and all traces have been
 		 * read by client, return EOF
@@ -420,13 +429,16 @@ static int ipc3_dtrace_enable(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, "can't set params for DMA for trace %d\n", ret);
 		goto trace_release;
 	}
 
 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, "Host dtrace trigger start failed: %d\n", ret);
@@ -507,7 +519,7 @@ int ipc3_dtrace_posn_update(struct snd_sof_dev *sdev,
 	if (!sdev->fw_trace_is_supported)
 		return 0;
 
-	if (sdev->dtrace_state == SOF_DTRACE_ENABLED &&
+	if (trace_pos_update_expected(sdev) &&
 	    sdev->host_offset != posn->host_offset) {
 		sdev->host_offset = posn->host_offset;
 		wake_up(&sdev->trace_sleep);

sound/soc/sof/sof-priv.h

@@ -464,6 +464,7 @@ struct snd_sof_ipc {
 enum sof_dtrace_state {
 	SOF_DTRACE_DISABLED,
 	SOF_DTRACE_STOPPED,
+	SOF_DTRACE_INITIALIZING,
 	SOF_DTRACE_ENABLED,
 };