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diff --git a/docs/plat/socionext-uniphier.rst b/docs/plat/socionext-uniphier.rst new file mode 100644 index 00000000..fb6ebe5e --- /dev/null +++ b/docs/plat/socionext-uniphier.rst @@ -0,0 +1,124 @@ +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 |