net: Add a module to manage nRF70 firmware in external flash

This module implements the necessary handling for store and use nRF70
firmware patches from the external flash, as this uses NCS tooling, this
is carved out from nRF70 driver as a separate module.

Implements SHEL-2988 partially.

Signed-off-by: Chaitanya Tata <[email protected]>

subsys/net/lib/Kconfig

@@ -47,5 +47,5 @@ rsource "wifi_ready/Kconfig"
 rsource "mqtt_helper/Kconfig"
 rsource "nrf_provisioning/Kconfig"
 rsource "mcumgr_smp_client/Kconfig"
-
+rsource "nrf70_fw_ext/Kconfig"
 endmenu

subsys/net/lib/nrf70_fw_ext/CMakeLists.txt

@@ -0,0 +1,12 @@
+#
+# Copyright (c) 2023 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+if (not CONFIG_NRF_WIFI_PATCHES_BUILTIN)
+zephyr_library_sources_ifdef(ext_fw_load.c)
+if(CONFIG_NRF_WIFI_PATCHES_EXT_FLASH_XIP)
+# Run patches from the external flash (XIP). No need to copy.
+zephyr_code_relocate(FILES ext_fw_load.c LOCATION EXTFLASH_RODATA NOCOPY)
+endif()

subsys/net/lib/nrf70_fw_ext/Kconfig

@@ -0,0 +1,94 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+choice NRF_WIFI_PATCHES_EXT_FLASH_SUPPORT
+	bool "Store nRF700x FW patches in external flash"
+	help
+	  Select this option to store nRF700x FW patches in external flash.
+	  This option helps to reduce the code memory size of the application, but
+	  requires external memory to be available for storing the FW patches.
+
+config NRF_WIFI_PATCHES_EXT_FLASH_DISABLED
+	bool "Store nRF700x FW patches in RAM"
+	select NRF_WIFI_PATCHES_BUILTIN
+
+config NRF_WIFI_PATCHES_EXT_FLASH_XIP
+	bool "Relocate nRF700x FW patches to external memory and execute from there"
+	# nRF7002 supports SPI based external flash access with no XIP
+	depends on !BOARD_NRF7002DK_NRF5340_CPUAPP && !BOARD_NRF7002DK_NRF5340_CPUAPP_NS
+	# Disable until Matter DFU changes are ready
+	# default y if BOARD_NRF5340DK_NRF5340_CPUAPP || BOARD_NRF52840DK_NRF52840
+	# For accessing external flash
+	select FLASH
+	# For relocation code to external flash
+	select XIP
+	select NORDIC_QSPI_NOR
+	select BUILD_NO_GAP_FILL
+	select CODE_DATA_RELOCATION
+	select HAVE_CUSTOM_LINKER_SCRIPT
+
+config NRF_WIFI_PATCHES_EXT_FLASH_STORE
+	bool "Store nRF700x FW patches in external memory but execute from RAM"
+	# nRF7002 supports SPI based external memory access but missing tools support
+	# TODO: Enable when tools support is available (NRFJPROG-157)
+	depends on !BOARD_NRF7002DK_NRF5340_CPUAPP && !BOARD_NRF7002DK_NRF5340_CPUAPP_NS
+	select FLASH
+	select FLASH_MAP
+endchoice
+
+if NRF_WIFI_PATCHES_EXT_FLASH_STORE
+config NRF_WIFI_FW_FLASH_CHUNK_SIZE
+	int "Chunk size for nRF70 FW patches to be read from external flash"
+	default 8192
+	help
+	  Chunk size for nRF70 FW patches to be read from external flash.
+	  This option impacts the loading time of the nRF70 FW patches and
+	  RAM usage (heap) of the application.
+
+config NRF_WIFI_FW_PATCH_INTEGRITY_CHECK
+	bool "Enable integrity check of nRF70 FW patches"
+	select FLASH_AREA_CHECK_INTEGRITY
+	default y
+	help
+	  Select this option to enable integrity check of nRF70 FW patches using
+	  SHA-256 verification algorithm.This option impacts the loading time of the
+	  nRF70 FW patches but protects against corrupted FW patches.
+
+config NRF_WIFI_FW_PATCH_DFU
+	bool "Direct Firmware Update of nRF70 FW patch"
+	depends on PARTITION_MANAGER_ENABLED
+	depends on BOOTLOADER_MCUBOOT
+	depends on !XIP_SPLIT_IMAGE
+	help
+	  Enabling this option adds support for Device Firmware Update (DFU)
+	  for the nRF70 Series Firmware Patch.
+
+	  This feature requires the addition of an MCUBoot partition pair:
+	  a primary and a secondary partition. These partitions are used to
+	  store the new firmware patch. The specific partition numbers to be used
+	  depend on the number of partitions already in use.
+
+	  The "nrf70_wifi_fw" partition must be added to the newly created
+	  MCUBoot primary partition. Once this Kconfig option is enabled,
+	  the nRF70.hex file will be signed by MCUBoot. The signed image
+	  will then be merged with the application image and flashed onto
+	  the target board.
+
+	  Ensure that the required MCUBoot partitions are properly configured
+	  before enabling this option. Refer to the documentation for detailed
+	  instructions on partition configuration and the DFU process.
+
+# TC is the default but Wi-Fi uses MbedTLS, so, to avoid loading another library.
+if NRF_WIFI_FW_PATCH_INTEGRITY_CHECK
+choice FLASH_AREA_CHECK_INTEGRITY_BACKEND
+	default FLASH_AREA_CHECK_INTEGRITY_MBEDTLS
+endchoice
+endif
+endif
+
+config CUSTOM_LINKER_SCRIPT
+	string "Custom linker script for nRF70 FW patches in external flash"
+	default "${ZEPHYR_BASE}/../nrf/subsys/net/lib/nrf70_fw_ext/rpu_fw_patches.ld"