[DistroKit] [PATCH 3/3] doc: RIoT: mention the 'fastboot' capabilities

[Juergen Borleis <jbe@pengutronix.de>]

Signed-off-by: Juergen Borleis <jbe@pengutronix.de>
---
 doc/hardware_v7a_riot.rst | 66 +++++++++++++++++++++++++++++++++++++++
 doc/testing.rst           |  2 ++
 2 files changed, 68 insertions(+)

diff --git a/doc/hardware_v7a_riot.rst b/doc/hardware_v7a_riot.rst
index 77b48cb..a6e2365 100644
--- a/doc/hardware_v7a_riot.rst
+++ b/doc/hardware_v7a_riot.rst
@@ -24,3 +24,69 @@ The serial boot console is available at the debug-header J18 at 115200 Baud and
 * J18.2: RxD
 * J18.3: GND
 
+Fast development
+----------------
+
+For development the RIoT-Board bootloader supports 'fastboot'. Refer
+:ref:`fast_development` for Linux and BSP preparation on demand.
+
+RIoT i.MX6S
+~~~~~~~~~~~
+
+The BSP already supports 'fastboot' and prepares the target accordingly.
+The PARTITION names might differ, so you should check first, what PARTITIONs
+are exported.
+
+To get the exported PARTITION names, available via 'fastboot', you can run::
+
+   $ fastboot getvar all
+   (bootloader) version: 0.4
+   (bootloader) bootloader-version: barebox-2023.02.1
+   (bootloader) max-download-size: 8388608
+   (bootloader) partition-size:mmc1: 00000000
+   (bootloader) partition-type:mmc1: unavailable
+   (bootloader) partition-size:mmc2: 00000000
+   (bootloader) partition-type:mmc2: unavailable
+   (bootloader) partition-size:mmc3: e5000000
+   (bootloader) partition-type:mmc3: basic
+   (bootloader) partition-size:ram-kernel: 00000000
+   (bootloader) partition-type:ram-kernel: file
+   (bootloader) partition-size:ram-initramfs: 00000000
+   (bootloader) partition-type:ram-initramfs: file
+   (bootloader) partition-size:ram-oftree: 00000000
+   (bootloader) partition-type:ram-oftree: file
+   (bootloader) partition-size:bbu-emmc: 000e0000
+   (bootloader) partition-type:bbu-emmc: basic
+
+In this example, the PARTITION names are 'mmc1', 'mmc2', 'mmc3', 'ram-kernel',
+'ram-initramfs', 'ram-oftree' and 'bbu-emmc'. In this example the two possible
+SD cards are not plugged in (e.g. "unavailable").
+
+.. note:: You need to restart the fastboot usbgadget, if you probe the SD cards
+          later on.
+
+Just connect the USB OTG connector to your host and run::
+
+   $ fastboot flash ram-kernel platform-v7a/images/linuximage -S 1
+   $ fastboot flash ram-oftree platform-v7a/images/imx6dl-riotboard.dtb -S 1
+   $ fastboot flash ram-initramfs platform-v7a/images/root.cpio.gz -S 1
+   $ fastboot oem exec -- boot ram-fastboot
+
+You can populate local memory like the eMMC as well. But only full memory
+devices and no particular partitions.
+
+If inserted, the regular SD card::
+
+   $ fastboot flash mmc1 platform-v7a/images/riotboard.hdimg -S 1
+
+If inserted, the µSD card::
+
+   $ fastboot flash mmc2 platform-v7a/images/riotboard.hdimg -S 1
+
+The built-in eMMC::
+
+   $ fastboot flash mmc3 platform-v7a/images/riotboard.hdimg -S 1
+
+.. note:: If you have no USB connection to the RIoT i.MX6S, you can use
+          a network connection instead. Just run all the 'fastboot' commands
+          shown above with the additional option '-s udp:<RIoT i.MX6S IP address>'.
diff --git a/doc/testing.rst b/doc/testing.rst
index 83bdb71..ef477cb 100644
--- a/doc/testing.rst
+++ b/doc/testing.rst
@@ -1,3 +1,5 @@
+.. _fast_development:
+
 Fast development
 ================
 
-- 
2.30.2