| ARM Trusted Firmware for Socionext UniPhier SoCs |
| ================================================ |
| |
| Socionext UniPhier ARMv8-A SoCs use ARM Trusted Firmware as the secure world |
| firmware, supporting BL1, BL2, and BL31. |
| |
| UniPhier SoC family implements its internal boot ROM, so BL1 is used as pseudo |
| ROM (i.e. runs in RAM). The internal boot ROM loads 64KB `1`_ image from a |
| non-volatile storage to the on-chip SRAM. Unfortunately, BL1 does not fit in |
| the 64KB limit if `Trusted Board Boot`_ (TBB) is enabled. To solve this problem, |
| Socionext provides a first stage loader called `UniPhier BL`_. This loader runs |
| in the on-chip SRAM, initializes the DRAM, expands BL1 there, and hands the |
| control over to it. Therefore, all images of ARM Trusted Firmware run in DRAM. |
| |
| The UniPhier platform works with/without TBB. See below for the build process |
| of each case. The image authentication for the UniPhier platform fully |
| complies with the Trusted Board Boot Requirements (TBBR) specification. |
| |
| The UniPhier BL does not implement the authentication functionality, that is, |
| it can not verify the BL1 image by itself. Instead, the UniPhier BL assures |
| the BL1 validity in a different way; BL1 is GZIP-compressed and appended to |
| the UniPhier BL. The concatenation of the UniPhier BL and the compressed BL1 |
| fits in the 64KB limit. The concatenated image is loaded by the boot ROM |
| (and verified if the chip fuses are blown). |
| |
| :: |
| |
| to the lowest common denominator. |
| |
| Boot Flow |
| --------- |
| |
| #. The Boot ROM |
| |
| This is hard-wired ROM, so never corrupted. It loads the UniPhier BL (with |
| compressed-BL1 appended) into the on-chip SRAM. If the SoC fuses are blown, |
| the image is verified by the SoC's own method. |
| |
| #. UniPhier BL |
| |
| This runs in the on-chip SRAM. After the minimum SoC initialization and DRAM |
| setup, it decompresses the appended BL1 image into the DRAM, then jumps to |
| the BL1 entry. |
| |
| #. BL1 |
| |
| This runs in the DRAM. It extracts BL2 from FIP (Firmware Image Package). |
| If TBB is enabled, the BL2 is authenticated by the standard mechanism of ARM |
| Trusted Firmware. |
| |
| #. BL2, BL31, and more |
| |
| They all run in the DRAM, and are authenticated by the standard mechanism if |
| TBB is enabled. See `Firmware Design`_ for details. |
| |
| Basic Build |
| ----------- |
| |
| BL1 must be compressed for the reason above. The UniPhier's platform makefile |
| provides a build target ``bl1_gzip`` for this. |
| |
| For a non-secure boot loader (aka BL33), U-Boot is well supported for UniPhier |
| SoCs. The U-Boot image (``u-boot.bin``) must be built in advance. For the build |
| procedure of U-Boot, refer to the document in the `U-Boot`_ project. |
| |
| To build minimum functionality for UniPhier (without TBB): |
| |
| :: |
| |
| make CROSS_COMPILE=<gcc-prefix> PLAT=uniphier BL33=<path-to-BL33> bl1_gzip fip |
| |
| Output images: |
| |
| - ``bl1.bin.gzip`` |
| - ``fip.bin`` |
| |
| Optional features |
| ----------------- |
| |
| - Trusted Board Boot |
| |
| `mbed TLS`_ is needed as the cryptographic and image parser modules. |
| Refer to the `User Guide`_ for the appropriate version of mbed TLS. |
| |
| To enable TBB, add the following options to the build command: |
| |
| :: |
| |
| TRUSTED_BOARD_BOOT=1 GENERATE_COT=1 MBEDTLS_DIR=<path-to-mbedtls> |
| |
| - System Control Processor (SCP) |
| |
| If desired, FIP can include an SCP BL2 image. If BL2 finds an SCP BL2 image |
| in FIP, BL2 loads it into DRAM and kicks the SCP. Most of UniPhier boards |
| still work without SCP, but SCP provides better power management support. |
| |
| To include SCP\_BL2, add the following option to the build command: |
| |
| :: |
| |
| SCP_BL2=<path-to-SCP> |
| |
| - BL32 (Secure Payload) |
| |
| To enable BL32, add the following option to the build command: |
| |
| :: |
| |
| SPD=<spd> BL32=<path-to-BL32> |
| |
| If you use TSP for BL32, ``BL32=<path-to-BL32>`` is not required. Just add the |
| following: |
| |
| :: |
| |
| SPD=tspd |
| |
| .. _1: Some%20SoCs%20can%20load%2080KB,%20but%20the%20software%20implementation%20must%20be%20aligned |
| .. _Trusted Board Boot: ../trusted-board-boot.rst |
| .. _UniPhier BL: https://github.com/uniphier/uniphier-bl |
| .. _Firmware Design: ../firmware-design.rst |
| .. _U-Boot: https://www.denx.de/wiki/U-Boot |
| .. _mbed TLS: https://tls.mbed.org/ |
| .. _User Guide: ../user-guide.rst |