SUIT: Flash companion

The SUIT flash companion sample allows the Secure Domain Firmware to access the external memory during the Software Updates for Internet of Things (SUIT) firmware upgrade.

Requirements

The sample supports the following development kit:

Hardware platforms

PCA

Board name

Board target

nRF54H20 DK

PCA10175

nrf54h20dk

nrf54h20dk/nrf54h20/cpuapp

Overview

The flash companion sample implements a device driver for the external flash device and provides an IPC service to the Secure Domain Firmware. The Secure Domain Firmware uses the IPC service to read, erase, or write data to the external memory.

The sample is meant to be booted by the Secure Domain while performing the firmware update process using the SUIT firmware upgrade.

The flash companion sample is not a stand-alone firmware, it is intended to be used with the nrf54h_suit_sample to complete a firmware transfer with external flash.

Configuration

See Configuring and building for information about how to permanently or temporarily change the configuration.

Setup

You can build the sample using sysbuild by enabling the SB_CONFIG_SUIT_BUILD_FLASH_COMPANION Kconfig option. The memory partition from which the firmware will run can be configured by providing a devicetree overlay through sysbuild. You should create a dedicated partition in non-volatile memory and override the zephyr,code-partition. The memory partition must not be used by any other firmware image.

The sample is booted during the SUIT firmware upgrade process. See the Firmware upgrade with external memory user guide to learn how to setup your sample to boot and use the flash companion’s services during firmware upgrade.

Configuration options

Check and configure the following configuration option:

SB_CONFIG_SUIT_BUILD_FLASH_COMPANION - Configuration for the firmware

This option enables the sample and builds it during the sysbuild.

Building and running

The flash companion sample is not a stand-alone firmware. To build it, open a different sample or application, such as samples/suit/smp_transfer. Make sure that both the main application and the flash companion support your target platform.

Perform the following steps in the main application directory:

  1. Enable the SB_CONFIG_SUIT_BUILD_FLASH_COMPANION sysbuild option.

  2. Create sysbuild/flash_companion.overlay devicetree overlay file and add the following content:

    1. Create a dedicated partition in non-volatile memory:

      &cpuapp_rx_partitions {
   cpuapp_slot0_partition: partition@a6000 {
      reg = <0xa6000 DT_SIZE_K(324)>;
   };
   companion_partition: partition@f7000 {
      reg = <0xf7000 DT_SIZE_K(36)>;
   };
};

      In the above example the executable memory partition of the main application (cpuapp_slot0_partition) is shrunk to make space for the flash companion executable memory partition (companion_partition).

    2. Apply the same memory partition configuration to the main application’s devicetree overlay.

    3. Enable SPI NOR devicetree node. In the case of nRF54H20 DK, you can enable the following node:

      &mx25uw63 {
   status = "okay";
};

  3. Build and flash the main application:

    west build -b nrf54h20dk/nrf54h20/cpuapp
west flash

The flash companion sample will be built flashed automatically by sysbuild.

Dependencies

This sample uses the following nRF Connect SDK libraries:

  • include/sdfw_services/ssf_client.h

  • zcbor

It uses the following Zephyr library:

The sample also uses drivers from nrfx.