boot/zephyr/Kconfig

# Copyright (c) 2017 Linaro Limited
# Copyright (c) 2020 Arm Limited
#
# SPDX-License-Identifier: Apache-2.0
#

mainmenu "MCUboot configuration"

comment "MCUboot-specific configuration options"

# Hidden option to mark a project as MCUboot
config MCUBOOT
	default y
	bool
	select MPU_ALLOW_FLASH_WRITE if ARM_MPU
	select USE_CODE_PARTITION if HAS_FLASH_LOAD_OFFSET

config BOOT_USE_MBEDTLS
	bool
	# Hidden option
	default n
	help
	  Use mbedTLS for crypto primitives.

config BOOT_USE_TINYCRYPT
	bool
	# Hidden option
	default n
	# When building for ECDSA, we use our own copy of mbedTLS, so the
	# Zephyr one must not be enabled or the MBEDTLS_CONFIG_FILE macros
	# will collide.
	depends on ! MBEDTLS
	help
	  Use TinyCrypt for crypto primitives.

config BOOT_USE_CC310
	bool
	# Hidden option
	default n
	# When building for ECDSA, we use our own copy of mbedTLS, so the
	# Zephyr one must not be enabled or the MBEDTLS_CONFIG_FILE macros
	# will collide.
	depends on ! MBEDTLS
	help
	  Use cc310 for crypto primitives.

config BOOT_USE_NRF_CC310_BL
	bool
	default n

config NRFXLIB_CRYPTO
	bool
	default n

config NRF_CC310_BL
	bool
	default n

menu "MCUBoot settings"

choice
	prompt "Signature type"
	default BOOT_SIGNATURE_TYPE_RSA

config BOOT_SIGNATURE_TYPE_RSA
	bool "RSA signatures"
	select BOOT_USE_MBEDTLS
	select MBEDTLS

if BOOT_SIGNATURE_TYPE_RSA
config BOOT_SIGNATURE_TYPE_RSA_LEN
	int "RSA signature length"
	range 2048 3072
	default 2048
endif

config BOOT_SIGNATURE_TYPE_ECDSA_P256
	bool "Elliptic curve digital signatures with curve P-256"

if BOOT_SIGNATURE_TYPE_ECDSA_P256
choice
	prompt "Ecdsa implementation"
	default BOOT_ECDSA_TINYCRYPT
config BOOT_ECDSA_TINYCRYPT
	bool "Use tinycrypt"
	select BOOT_USE_TINYCRYPT
config BOOT_CC310
	bool "Use CC310"
	select BOOT_USE_NRF_CC310_BL if HAS_HW_NRF_CC310
	select NRF_CC310_BL if HAS_HW_NRF_CC310
	select NRFXLIB_CRYPTO if SOC_FAMILY_NRF
	select BOOT_USE_CC310
endchoice
endif

config BOOT_SIGNATURE_TYPE_ED25519
	bool "Edwards curve digital signatures using ed25519"

if BOOT_SIGNATURE_TYPE_ED25519
choice
	prompt "Ecdsa implementation"
	default BOOT_ED25519_TINYCRYPT
config BOOT_ED25519_TINYCRYPT
	bool "Use tinycrypt"
	select BOOT_USE_TINYCRYPT
config BOOT_ED25519_MBEDTLS
	bool "Use mbedTLS"
	select BOOT_USE_MBEDTLS
	select MBEDTLS
endchoice
endif

endchoice

config BOOT_SIGNATURE_KEY_FILE
	string "PEM key file"
	default ""
	help
	  The key file will be parsed by imgtool's getpub command and a .c source
	  with the public key information will be written in a format expected by
	  MCUboot.

config MBEDTLS_CFG_FILE
	default "mcuboot-mbedtls-cfg.h"

config BOOT_VALIDATE_SLOT0
	bool "Validate image in the primary slot on every boot"
	default y
	help
	  If y, the bootloader attempts to validate the signature of the
	  primary slot every boot. This adds the signature check time to
	  every boot, but can mitigate against some changes that are
	  able to modify the flash image itself.

config BOOT_UPGRADE_ONLY
	bool "Overwrite image updates instead of swapping"
	default n
	help
	  If y, overwrite the primary slot with the upgrade image instead
	  of swapping them. This prevents the fallback recovery, but
	  uses a much simpler code path.

config BOOT_SWAP_USING_MOVE
	bool "Swap mode that can run without a scratch partition"
	default y if SOC_FAMILY_NRF
	default n
	help
	  If y, the swap upgrade is done in two steps, where first every
	  sector of the primary slot is moved up one sector, then for
	  each sector X in the secondary slot, it is moved to index X in
	  the primary slot, then the sector at X+1 in the primary is
	  moved to index X in the secondary.
	  This allows a swap upgrade without using a scratch partition,
	  but is currently limited to all sectors in both slots being of
	  the same size.

config BOOT_BOOTSTRAP
	bool "Bootstrap erased the primary slot from the secondary slot"
	default n
	help
	  If y, enables bootstraping support. Bootstrapping allows an erased
	  primary slot to be initialized from a valid image in the secondary slot.
	  If unsure, leave at the default value.

config BOOT_SWAP_SAVE_ENCTLV
	bool "Save encrypted key TLVs instead of plaintext keys in swap metadata"
	default n
	help
	  If y, instead of saving the encrypted image keys in plaintext in the
	  swap resume metadata, save the encrypted image TLVs. This should be used
	  when there is no security mechanism protecting the data in the primary
	  slot from being dumped. If n is selected (default), the keys are written
	  after being decrypted from the image TLVs and could be read by an
	  attacker who has access to the flash contents of the primary slot (eg
	  JTAG/SWD or primary slot in external flash).
	  If unsure, leave at the default value.

config BOOT_ENCRYPT_RSA
	bool "Support for encrypted upgrade images using RSA"
	default n
	help
	  If y, images in the secondary slot can be encrypted and are decrypted
	  on the fly when upgrading to the primary slot, as well as encrypted
	  back when swapping from the primary slot to the secondary slot. The
	  encryption mechanism used in this case is RSA-OAEP (2048 bits).

config BOOT_ENCRYPT_EC256
	bool "Support for encrypted upgrade images using ECIES-P256"
	default n
	help
	  If y, images in the secondary slot can be encrypted and are decrypted
	  on the fly when upgrading to the primary slot, as well as encrypted
	  back when swapping from the primary slot to the secondary slot. The
	  encryption mechanism used in this case is ECIES using primitives
	  described under "ECIES-P256 encryption" in docs/encrypted_images.md.

config BOOT_MAX_IMG_SECTORS
	int "Maximum number of sectors per image slot"
	default 128
	help
	  This option controls the maximum number of sectors that each of
	  the two image areas can contain. Smaller values reduce MCUboot's
	  memory usage; larger values allow it to support larger images.
	  If unsure, leave at the default value.

config BOOT_ERASE_PROGRESSIVELY
	bool "Erase flash progressively when receiving new firmware"
	default y if SOC_NRF52840
	help
	 If enabled, flash is erased as necessary when receiving new firmware,
	 instead of erasing the whole image slot at once. This is necessary
	 on some hardware that has long erase times, to prevent long wait
	 times at the beginning of the DFU process.

config BOOT_WAIT_FOR_USB_DFU
	bool "Wait for a prescribed duration to see if USB DFU is invoked"
	default n
	select USB
	select USB_DFU_CLASS
	select IMG_MANAGER
	help
	  If y, MCUboot waits for a prescribed duration of time to allow
	  for USB DFU to be invoked. Please note DFU always updates the
	  slot1 image.

config ZEPHYR_TRY_MASS_ERASE
	bool "Try to mass erase flash when flashing MCUboot image"
	default y
	help
	  If y, attempt to configure the Zephyr build system's "flash"
	  target to mass-erase the flash device before flashing the
	  MCUboot image. This ensures the scratch and other partitions
	  are in a consistent state.

	  This is not available for all targets.

config BOOT_USE_BENCH
        bool "Enable benchmark code"
        default n
        help
          If y, adds support for simple benchmarking that can record
          time intervals between two calls.  The time printed depends
          on the particular Zephyr target, and is generally ticks of a
          specific board-specific timer.

module = MCUBOOT
module-str = MCUBoot bootloader
source "subsys/logging/Kconfig.template.log_config"

menuconfig MCUBOOT_SERIAL
	bool "MCUboot serial recovery"
	default n
	select REBOOT
	select GPIO
	select SERIAL
	select UART_INTERRUPT_DRIVEN
	select BASE64
	select TINYCBOR
	help
	  If y, enables a serial-port based update mode. This allows
	  MCUboot itself to load update images into flash over a UART.
	  If unsure, leave at the default value.

if MCUBOOT_SERIAL

choice
	prompt "Serial device"
	default BOOT_SERIAL_UART if !BOARD_NRF52840_PCA10059
	default BOOT_SERIAL_CDC_ACM if BOARD_NRF52840_PCA10059

config BOOT_SERIAL_UART
	bool "UART"
	# SERIAL and UART_INTERRUPT_DRIVEN already selected

config BOOT_SERIAL_CDC_ACM
	bool "CDC ACM"
	select USB
	select USB_DEVICE_STACK
	select USB_CDC_ACM

endchoice

config BOOT_MAX_LINE_INPUT_LEN
	int "Maximum command line length"
	default 512
	help
	  Maximum length of commands transported over the serial port.

config BOOT_SERIAL_DETECT_PORT
	string "GPIO device to trigger serial recovery mode"
	default GPIO_0 if SOC_FAMILY_NRF
	help
	  Zephyr GPIO device which contains the pin used to trigger
	  serial recovery mode.

config BOOT_SERIAL_DETECT_PIN
	int "Pin to trigger serial recovery mode"
	default 6 if BOARD_NRF9160_PCA10090
	default 11 if BOARD_NRF52840_PCA10056
	default 13 if BOARD_NRF52_PCA10040
	default 23 if BOARD_NRF5340_DK_NRF5340_CPUAPP || BOARD_NRF5340_DK_NRF5340_CPUAPPNS
	help
	  Pin on the serial detect port which triggers serial recovery mode.

config BOOT_SERIAL_DETECT_PIN_VAL
	int "Serial detect pin trigger value"
	default 0
	range 0 1
	help
	  Logic value of the detect pin which triggers serial recovery
	  mode.

# Workaround for not being able to have commas in macro arguments
DT_CHOSEN_Z_CONSOLE := zephyr,console

config RECOVERY_UART_DEV_NAME
	string "UART Device Name for Recovery UART"
	default "$(dt_chosen_label,$(DT_CHOSEN_Z_CONSOLE))" if HAS_DTS
	default "UART_0"
	depends on BOOT_SERIAL_UART
	help
	  This option specifies the name of UART device to be used for
	  serial recovery.

endif # MCUBOOT_SERIAL

endmenu

config MCUBOOT_DEVICE_SETTINGS
	# Hidden selector for device-specific settings
	bool
	default y
        # CPU options
	select MCUBOOT_DEVICE_CPU_CORTEX_M0 if CPU_CORTEX_M0
        # Enable flash page layout if available
	select FLASH_PAGE_LAYOUT if FLASH_HAS_PAGE_LAYOUT
	# Enable flash_map module as flash I/O back-end
	select FLASH_MAP

config MCUBOOT_DEVICE_CPU_CORTEX_M0
	# Hidden selector for Cortex-M0 settings
	bool
	default n
	select SW_VECTOR_RELAY if !CPU_CORTEX_M0_HAS_VECTOR_TABLE_REMAP

comment "Zephyr configuration options"

# Disabling MULTITHREADING provides a code size advantage, but
# it requires peripheral drivers (particularly a flash driver)
# that works properly with the option enabled.
#
# If you know for sure that your hardware will work, you can default
# it to n here. Otherwise, having it on by default makes the most
# hardware work.
config MULTITHREADING
	default y if BOOT_SERIAL_CDC_ACM #usb driver requires MULTITHREADING
	default n if SOC_FAMILY_NRF
	default y

config LOG_IMMEDIATE
	default n if MULTITHREADING

config UPDATEABLE_IMAGE_NUMBER
	int "Number of updateable images"
	default 1
	help
	  Enables support of multi image update.

choice
	prompt "Downgrade prevention"
	optional

config MCUBOOT_DOWNGRADE_PREVENTION
	bool "SW based downgrade prevention"
	depends on BOOT_UPGRADE_ONLY
	help
	  Prevent downgrades by enforcing incrementing version numbers.
	  When this option is set, any upgrade must have greater major version
	  or greater minor version with equal major version. This mechanism
	  only protects against some attacks against version downgrades (for
	  example, a JTAG could be used to write an older version).

config MCUBOOT_HW_DOWNGRADE_PREVENTION
	bool "HW based downgrade prevention"
	help
	  Prevent undesirable/malicious software downgrades. When this option is
	  set, any upgrade must have greater or equal security counter value.
	  Because of the acceptance of equal values it allows for software
	  downgrade to some extent.

endchoice

source "Kconfig.zephyr"