[nrfconnect] Update DFU documentation with info about Matter OTA (#13751

)

* [nrfconnect] Add description of the OTA testing procedure

Signed-off-by: Damian Krolik <[email protected]>

* Restyled by prettier-markdown

* Apply review comments

* More review comments

* Restyled by prettier-markdown

* Silence mispell check

Co-authored-by: Restyled.io <[email protected]>

.github/.wordlist.txt

@@ -845,6 +845,7 @@ RendezVousTest
 repo
 req
 Requestor
+Requestors
 responder
 retargeting
 reusability

docs/guides/nrfconnect_examples_software_update.md

@@ -1,15 +1,86 @@
 # Performing Device Firmware Upgrade in the nRF Connect examples
 
 Some examples for the development kits from Nordic Semiconductor support
-over-the-air Device Firmware Upgrade.
+over-the-air (OTA) Device Firmware Upgrade (DFU) using one of the following
+protocols:
 
-Currently, the Bluetooth LE is the only available transport for performing the
-DFU operation and it uses nRF Connect SDK's
-[Simple Management Protocol](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/guides/device_mgmt/index.html#device-mgmt).
-The upgrade can be done either using a smartphone application or a PC command
-line tool.
+-   Matter-compliant OTA update protocol that uses the Matter operational
+    network for querying and downloading a new firmware image.
+-   [Simple Management Protocol](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/guides/device_mgmt/index.html#device-mgmt)
+    over Bluetooth LE. In this case, the DFU can be done either using a
+    smartphone application or a PC command line tool. Note that this protocol is
+    not part of the Matter specification.
 
-## Device Firmware Upgrade using smartphone
+## Device Firmware Upgrade over Matter
+
+> **_NOTE:_** The procedure presented below requires that you have OpenThread
+> Border Router (OTBR) set up either in Docker or on a Raspberry Pi. Read
+> [Setup OpenThread Border Router on Raspberry Pi](openthread_border_router_pi.md)
+> to learn how to install the OTBR on a Raspberry Pi.
+
+The DFU over Matter involves two kinds of nodes: OTA Provider and OTA Requestor.
+An OTA Provider is a node that can respond to the OTA Requestors' queries about
+available software updates and share the update packages with them. An OTA
+Requestor is any node that needs to be updated and can communicate with the OTA
+Provider to fetch applicable software updates. In the procedure described below,
+the OTA Provider will be a Linux application and the example running on the
+Nordic Semiconductor's board will work as the OTA Requestor.
+
+To test the DFU over Matter, you need to complete the following steps:
+
+1.  Navigate to the CHIP root directory.
+2.  Build the OTA Provider application for Linux:
+
+        $ scripts/examples/gn_build_example.sh examples/ota-provider-app/linux out/provider chip_config_network_layer_ble=false
+
+3.  Build chip-tool for Linux:
+
+        $ scripts/examples/gn_build_example.sh examples/chip-tool out/chiptool 'chip_mdns="platform"'
+
+4.  Run OTA Provider application with _app_update.bin_ replaced with the path to
+    the new firmware image which you wish to provide to the Matter device:
+
+         $ out/provider/chip-ota-provider-app -f app_update.bin
+
+    Keep the application running and use another terminal for the remaining
+    steps.
+
+5.  Commission the OTA Provider into the Matter network using Node Id 1:
+
+        $ ./out/chiptool/chip-tool pairing onnetwork 1 20202021
+
+6.  Use the OTBR web interface to form a new Thread network using the default
+    network settings.
+7.  Commission the Matter device into the same Matter network using Node Id 2.
+    The parameter starting with the _hex:_ prefix is the Thread network's Active
+    Operational Dataset. It can be retrieved from the OTBR in case you have
+    changed the default network settings when forming the network.
+
+         $ ./out/chiptool/chip-tool pairing ble-thread 2 hex:000300000f02081111111122222222051000112233445566778899aabbccddeeff01021234 20202021 3840
+
+8.  Initiate the DFU procedure in one of the following ways:
+
+    -   If you have built the device firmware with `-DCONFIG_CHIP_LIB_SHELL=y`
+        option, which enables Matter shell commands, run the following command
+        on the device shell. The numeric arguments are Fabric Index, Provider
+        Node Id and Provider Endpoint Id, respectively.
+
+               $ matter ota query 1 1 0
+
+    -   Otherwise, use chip-tool to send the Announce OTA Provider command to
+        the device. The numeric arguments are Provider Node Id, Provider Vendor
+        Id, Announcement Reason, Provider Endpoint Id, Requestor Node Id and
+        Requestor Endpoint Id, respectively.
+
+               $ ./out/chiptool/chip-tool otasoftwareupdaterequestor announce-ota-provider 1 0 0 0 2 0
+
+        Once the device is made aware of the OTA Provider node, it automatically
+        queries the OTA Provider for a new firmware image.
+
+9.  When the firmware image download is complete, reboot the device to apply the
+    update.
+
+## Device Firmware Upgrade over Bluetooth LE using smartphone
 
 To upgrade your device firmware over Bluetooth LE using smartphone, complete the
 following steps:
@@ -30,7 +101,7 @@ following steps:
    [FOTA upgrades](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/ug_nrf52.html#fota-upgrades)
    page in the nRF Connect SDK documentation.
 
-## Device Firmware Upgrade using PC command line tool
+## Device Firmware Upgrade over Bluetooth LE using PC command line tool
 
 To upgrade your device firmware over Bluetooth LE, you can use the PC command
 line tool provided by the [mcumgr](https://github.com/zephyrproject-rtos/mcumgr)