How to configure TF-A FIP

Applicable for

1. Article purpose[edit source]

This section details the Trusted Firmware-A FIP (Firmware Image Package) usage in the STM32 MPU boot chain. It explains how to use it in STM32 MPU context and describes the build/update process that is required to deploy it on your target.

2. Overview[edit source]

The FIP is used by the Trusted Firmware-A BL2 firmware to load and authenticate the next stage binaries.

The FIP follows the Trusted Firmware-A specification^[1].

It must contains:

All the boot stage firmware loaded by Trusted Firmware-A BL2.
Configuration files.

Warning

If Trusted Firmware-A BL2 is built with TRUSTED_BOARD_BOOT enabled, the FIP must also contains:

Certificates (X509.3 based) for authentication.

3. Firmware Image Package creation tool[edit source]

Trusted Firmware-A provides a dedicated tool name fiptool to create a FIP.^[2]

Information

By default, the OpenSTLinux SDK provides the fiptool command. You do not need to regenerate it to update (or create) a FIP binary.

If you want to regenerate it, you must follow the official documentation..^[3]
The official documentation introduces the different available options.

Here is the list of the most useful options:

Options	Description	Example
help	Show all available options supported	fiptool help
info	List the content of a FIP: offset in the FIP size in the FIP cmdline option to modify the binary	fiptool info fip.bin Secure Payload BL32 (Trusted OS): offset=0x128, size=0x2C, cmdline="--tos-fw" Secure Payload BL32 Extra1 (Trusted OS Extra1): offset=0x154, size=0x18750, cmdline="--tos-fw-extra1" Secure Payload BL32 Extra2 (Trusted OS Extra2): offset=0x188A4, size=0x56000, cmdline="--tos-fw-extra2" Non-Trusted Firmware BL33: offset=0x6E8A4, size=0xECE98, cmdline="--nt-fw" FW_CONFIG: offset=0x15B73C, size=0x1FA, cmdline="--fw-config" HW_CONFIG: offset=0x15B936, size=0x1BC08, cmdline="--hw-config"
update	Update allows one or more images to be replaced in an existing FIP binary	fiptool update --tos-fw bl32.bin fip.bin
unpack	Extracts all binaries from a FIP binary	fiptool unpack fip.bin
remove	Removes a binary from FIP binary	fiptool remove --tos-fw bl32.bin fip.bin

4. FIP binary creation[edit source]

Below the list of the different ways by which the FIP binary can be generated:

Using the dedicated fiptool command
Using the Trusted Firmware-A official Makefile

4.1. STM32MP1[edit source]

The OpenSTLinux boot flow requires the following stages to be loaded:

BL32: Secure OS OP-TEE OS (or Secure Monitor SP-MIN on STM32MP15x lines )
BL33: The non-secure firmware (recommended U-Boot)
HW_config: The OpenSTLinux uses the hw_config as the non-secure device tree
FW_config: Firmware configuration file listing the previous images and defining their size and the load address

The Trusted Firmware-A Makefile with fip target and some variables uses fiptool to automatically create the new FIP after the Trusted Firmware-A compilation.

With U-Boot as a non-secure firmware, the paths for the files used in next chapters are the following:

Description	Makefile variable	fiptool option	File path for OP-TEE	File path for SP_MIN Limited to STM32MP15x lines
Secure OS (OP-TEE) or Secure Monitor (SPMIN)	BL32	--tos-fw	<optee_path>/tee-header_v2.bin	<tfa_path>/bl32.bin
OP-TEE pager	BL32_EXTRA1	--tos-fw-extra1	<optee_path>/tee-pager_v2.bin	-
OPTEE pageable	BL32_EXTRA2	--tos-fw-extra2	<optee_path>/tee-pageable_v2.bin	-
Firmware configuration file	FW_CONFIG	--fw-config	<tfa_path>/fw-config.dtb
U-Boot device tree	BL33_CFG	--hw-config	<u-boot_path>/u-boot.dtb
U-Boot	BL33	--nt-fw	<u-boot_path>/u-boot-nodtb.bin

Warning

If Trusted Firmware-A BL2 is built with TRUSTED_BOARD_BOOT enabled, some specific options and files are required. See the Trusted boot page for more details.

4.2. Updating the FIP binary[edit source]

When modifying a component included in the FIP binary, it is possible to update only part of the binary. To do this, use the fiptool update command.

Example when a new U-Boot is generated, the FIP must be updated using the following commands:

Full U-Boot update (U-Boot Binary and U-Boot Device tree)

 fiptool update --nt-fw <u-boot_path>/u-boot-nodtb.bin --hw-config <u-boot_path>/u-boot.dtb fip.bin

Warning

When updating a binary in the FIP when the Trusted Firmware-A BL2 is built with TRUSTED_BOARD_BOOT enabled, the content certificate must be updated too. See the Trusted Board Boot for more details.

5. Updating the software on board[edit source]

5.1. Partitioning of binaries[edit source]

The FIP build provides a binary named fip.bin (or fip-<board-name>-<bootchain>.bin from official release) that MUST be copied to a dedicated partition named fip, fip-a or fip-b when Secure Firmware Update is enabled.

5.2. Updating via SDCard[edit source]

If you use an SDCard, simply update the FIP binary by using the dd command on your host.
Plug your SDCard into the computer and copy the binary to the dedicated partition; on an SDCard/USB disk the fip partition or fip-a/fip-b when Secure Firmware Update is enabled:

 - SDCard: /dev/mmcblkXpY (where X is the instance number, Y is the partition number of the FIP)
 - SDCard via USB reader: /dev/sdXY (where X is the instance number, Y is the partition number of the FIP))

Under Linux^®

   dd if=<fip binary file> of=/dev/<device partition> bs=1M conv=fdatasync

Information

To find the partition associated to a specific label, just plug the SDCard/USB disk into your PC and call the following command:

   ls -l /dev/disk/by-partlabel/
 total 0
 lrwxrwxrwx 1 root root 10 May  3 15:14 bootfs -> ../../sda8
 lrwxrwxrwx 1 root root 10 May  3 15:14 fip-a -> ../../sda5           FIP (Image A)
 lrwxrwxrwx 1 root root 10 May  3 15:14 fip-b -> ../../sda6           FIP (Image B)
 lrwxrwxrwx 1 root root 10 May  3 15:14 fsbl1 -> ../../sda1           FSBL1 (Trusted Firmware-A BL2)
 lrwxrwxrwx 1 root root 10 May  3 15:14 fsbl2 -> ../../sda2           FSBL2 (Trusted Firmware-A BL2 backup)
 lrwxrwxrwx 1 root root 10 May  3 15:14 metadata1 -> ../../sda3
 lrwxrwxrwx 1 root root 10 May  3 15:14 metadata2 -> ../../sda4
 lrwxrwxrwx 1 root root 11 May  3 15:14 rootfs -> ../../sda10
 lrwxrwxrwx 1 root root 10 May  3 15:14 u-boot-env -> ../../sda7
 lrwxrwxrwx 1 root root 11 May  3 15:14 userfs -> ../../sda11
 lrwxrwxrwx 1 root root 10 May  3 15:14 vendorfs -> ../../sda9

Under Windows^®

CoreUtils ^[4] that includes the dd command is available for Windows.

5.3. Updating via USB mass storage on U-boot[edit source]

See How to use USB mass storage in U-Boot.

Refer to the previous section to put FIP binary into SDCard/USB disk.

5.4. Updating your boot device via STM32CubeProgrammer[edit source]

Refer to the STM32CubeProgrammer documentation for details on how to update your target.

6. References[edit source]

[1] Firmware Image Package design

[2] Firmware Image Package tool

[3] Building and using the fiptool

[4] ttp://gnuwin32.sourceforge.net/packages/coreutils.htm

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