developer_guides: debugability: probes: Rewrite probes logging enable quide

One of the PRs for automatic enabling of logging through probes
interface was not accepted, and since there is not better alternative
to enable the logs at the moment, document the old mething for enabling
them.

Restructure the documrent a bit while at it.

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

Author: jsarha

developer_guides/debugability/probes/index.rst

@@ -12,11 +12,15 @@ from each buffer.
 Requirements
 ************
 
+.. _install-tinycompress:
+
 - Install `tinycompress <https://github.com/alsa-project/tinycompress>`_ (crecord tool)
 
 Enabling Probes
 ***************
 
+.. _kernel-side:
+
 Kernel side
 ===========
 
@@ -55,6 +59,8 @@ Kernel side
 
      cat /proc/asound/cards | grep sofprobes
 
+.. _firmware-side:
+
 Firmware side
 =============
 
@@ -81,13 +87,9 @@ Firmware side
 	CONFIG_LOG_BACKEND_SOF_PROBE=y
 	CONFIG_ZEPHYR_LOG=y
 
-  This option enables the probes logging automatically when probes extraction DMA is started:
+  Refer to :ref:`Simple logging case<simple-logging-case>` for quick guide to use probes logging interface.
 
-  .. 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.
+- Refer to **Step 3 Build firmware binaries** in :ref:`Build SOF from Scratch <build-from-scratch>` for reference on how to build SOF FW.
 
 Note that you do not need to modify the audio topology file.
 
@@ -195,22 +197,12 @@ the last stage of extraction.
 						 */
 		} __attribute__((packed, aligned(4)));
 
-Enabling the log in IPC3 system (in case auto enable is not on):
-
-   .. code-block:: bash
-
-	  echo 0,1,0 > probe_points
-
-And on IPC4 system:
-
-   .. code-block:: bash
-
-	  echo 0,0,0 > probe_points
-
 2. Unpause the playback stream. (optional)
 #. Close the playback stream when done.
 #. Close the crecord tool.
 
+.. _data-parsing:
+
 Data parsing
 ************
 
@@ -230,12 +222,29 @@ Usage and ouput:
 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``.
 
+.. _simple-logging-case:
 
 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:
+With the :ref:`crecord<install-tinycompress>` and :ref:`sof-probes<data-parsing>` in path, FW built with :ref:`probes logging enabled<firmware-side>`, and probes enabled from :ref:`Linux side<kernel-side>`, it should be possible to extract the logs with following steps:
+
+#. crecord has to be started first:
 
 .. code-block:: bash
 
 	crecord -c3 -d0 -b8192 -f4 -FS32_LE -R48000 -C4 | sof-probes -l
+
+#. then to enable logs through probes sysfw interface use following commands as root,
+
+     IPC3 system:
+
+.. code-block:: bash
+
+	echo 0,1,0 > /sys/kernel/debug/sof/probe_points
+
+     IPC4 system:
+
+.. code-block:: bash
+
+	echo 0,0,0 > /sys/kernel/debug/sof/probe_points