Firmware patches in the external memory

This guide explains the available options for having the nRF70 Series firmware patches reside in the external memory.

Note

External memory refers to the memory that is outside the SoC, for example, an external flash memory chip, or external non-volatile memory (NVM) chip.

Overview

By default, the nRF70 Series firmware patches are built as part of the nRF Wi-Fi driver code, residing in on-chip memory. The firmware patches include code that is executed on the nRF70 Series device. The size of the firmware patches might be considerably large, which limits the amount of on-chip code memory available for the user application. In order to increase the amount of on-chip memory available for user applications, the nRF Wi-Fi driver supports the option of using external memory, if that is available.

Prerequisites

Before using this feature, make sure that the following prerequisites are completed:

  • The external memory must be available and configured in the devicetree.

  • The external memory must be large enough to store the firmware patches, taking into consideration also the patch upgrade requirement, for example, Device Firmware Update (DFU). The maximum size of all the firmware patches combined is 128 KB.

Note

Currently, in Nordic Semiconductor SoCs, access to external memory and the Execute in Place (XIP) feature are available through the QSPI interface only.

Supported platforms

The following platforms are supported:

  • nRF5340 DK with nRF7002 EK as a shield

  • nRF52840 DK with nRF7002 EK as a shield

Note

Due to limitations mentioned above, the nRF7002 DK is not supported as it needs access to external memory through the SPI interface.

Available options

There are two supported options for offloading the firmware patches in the external memory feature:

  • Using XIP access

  • Using QSPI transfers to RAM

Using XIP access

If the application supports XIP from external memory, then the firmware patches can be loaded as part of the nRF Wi-Fi driver code (RODATA) and then relocated to the external memory. The nRF Wi-Fi driver accesses the firmware patches using XIP feature and downloads the firmware patches to the nRF70 device. To enable this feature, set the CONFIG_NRF_WIFI_PATCHES_EXT_FLASH_XIP Kconfig option to y. Once the build is complete, the feature can be verified by checking the memory regions summary in the build output. A new memory region called EXTFLASH is added to the memory regions summary, and the firmware patches are placed in this region. The size of the FLASH used is reduced by the size of the firmware patches.

Following is a sample summary of the memory regions:

Memory region         Used Size  Region Size  %age Used
      EXTFLASH:       64544 B         8 MB      0.77%
         FLASH:      618752 B         1 MB     59.01%
           RAM:      170636 B       448 KB     37.20%
      IDT_LIST:          0 GB         2 KB      0.00%

Using QSPI transfers to RAM

The nRF Wi-Fi driver supports the option for offloading the nRF70 firmware patch to external non-XIP memory. In this case the upload of the firmware patch from the external memory to the nRF70 device happens in two stages:

  1. The firmware patch is loaded from the external memory onto internal RAM.

  2. The firmware patch is uploaded to the nRF70 device.

This feature can be enabled using DTS or Snippets feature or by using Partition Manager.

Configuration

The following configuration options are available:

The external memory partition name must be defined in the devicetree or in the partition manager configuration file.

  • nrf70_fw_partition - Defines the name of the external memory partition that stores the firmware patches. This must be defined in the devicetree, for example:

&flash0 {
    partitions {
        compatible = "fixed-partitions";
        #address-cells = <1>;
        #size-cells = <1>;
        nrf70_fw_partition: partition@0 {
            label = "nrf70_fw_partition";
            reg = <0x00000000 DT_SIZE_K(128)>;
        };
    };
};

  • nrf70_wifi_fw - Defines the name of the external memory partition that stores the firmware patches. This must be defined in the partition manager configuration file, for example:

nrf70_wifi_fw:
  address: 0x12f000
  size: 0x20000
  device: MX25R64
  region: external_flash

Building

See Getting started with nRF7002 DK for general instructions on building.

Additionally, you must enable either the nrf70-fw-patch-ext-flash snippet or the CONFIG_PARTITION_MANAGER_ENABLED option.

For example, to build the Wi-Fi: Shell sample for the nRF5340 DK with the nrf70-fw-patch-ext-flash snippet enabled, run the following commands.

With west
west build -p -b nrf5340dk_nrf5340_cpuapp -S nrf70-fw-patch-ext-flash samples/wifi/shell -- -DSHIELD=nrf7002ek
With CMake
cmake -GNinja -Bbuild -DBOARD=nrf5340dk_nrf5340_cpuapp -DSHIELD=nrf7002ek -DSNIPPET=nrf70-fw-patch-ext-flash samples/wifi/shell
ninja -C build

For example, to build the Wi-Fi: Shell sample for the nRF5340 DK with the CONFIG_PARTITION_MANAGER_ENABLED option enabled, run the following commands:

With west
west build -p -b nrf5340dk_nrf5340_cpuapp samples/wifi/shell -- -DSHIELD=nrf7002ek -DCONFIG_PARTITION_MANAGER_ENABLED=y -DCONFIG_NRF_WIFI_PATCHES_EXT_FLASH_STORE=y
With CMake
cmake -GNinja -Bbuild -DBOARD=nrf5340dk_nrf5340_cpuapp -DSHIELD=nrf7002ek -DCONFIG_PARTITION_MANAGER_ENABLED=y -DCONFIG_NRF_WIFI_PATCHES_EXT_FLASH_STORE=y samples/wifi/shell
ninja -C build

Programming

To program the firmware image with the firmware patches stored in the external memory, use the following commands.

With west

No changes are needed to the programming command:

west flash
With other tools

You must use the merged.hex file instead of the zephyr.hex file to choose the program image explicitly.

For example, for nrfjprog:

nrfjprog -f nrf53 -s 0 --program build/zephyr/merged.hex ---sectorerase --qspisectorerase --verify --reset

Updating firmware patches

You can update the firmware patches using all available DFU alternatives described in the main Device Firmware Updates page. To do it, you need to use MCUboot bootloader and create proper partitions to allow storing and replacing the firmware patches.

To learn how to prepare your application and perform the firmware patch update, see the Firmware patch update page.