developer_guides: debugability: probes: Logging backend sof-probes update

Added firmware kconfig options for enabling probes and logging
backend. Also added notes about the latest updates for sof-probes
demuxing tool.

Signed-off-by: Jyri Sarha <[email protected]>

Author: jsarha

developer_guides/debugability/probes/index.rst

@@ -65,6 +65,28 @@ Firmware side
 
 	 make menuconfig
 
+  The following options available
+
+  Required for audio probes:
+
+  .. code-block:: bash
+
+	CONFIG_PROBE=y			# enable probes
+	CONFIG_PROBE_POINTS_MAX=16	# max probepoints
+
+  Required for logging through probes interface:
+
+  .. code-block:: bash
+
+	CONFIG_LOG_BACKEND_SOF_PROBE=y
+	CONFIG_ZEPHYR_LOG=y
+
+  This option enables the probes logging automatically when probes extraction DMA is started:
+
+  .. code-block:: bash
+
+	CONFIG_LOG_BACKEND_SOF_PROBE_OUTPUT_AUTO_ENABLE=y
+
 - Refer to **Step 3 Build firmware binaries** in :ref:`Build SOF from Scratch <build-from-scratch>` for reference.
 
 Note that you do not need to modify the audio topology file.
@@ -101,6 +123,7 @@ the last stage of extraction.
      - Pause the playback stream. (optional)
      - Add probe points via the ``debugfs`` "probe_points" entry in ``/sys/kernel/debug/sof``
 
+
    For example, to add a buffer with 7 probe points:
 
    .. code-block:: bash
@@ -159,4 +182,14 @@ Usage and ouput:
    sof-probes:	 done
 
 As a result, ``buffer_7.wav`` is generated in the *tools/build_tools/probes* folder. The wave file can then be examined with your tool of choice
-such as ``Audacity``.
+such as ``Audacity``.
+
+
+Simple logging case
+*******************
+
+With the crecord and sof-probes in path, probes logging backend with auto enable option it is possible to get the firmware logs to stdout with this command combination:
+
+.. code-block:: bash
+
+	crecord -c3 -d0 -b8192 -f4 -FS32_LE -R48000 -C4 | sof-probes -l