1RD-Aspen (Zena CSS) Platform 2============================ 3 4The RD-Aspen platform, as referenced in TF-A, includes the following features: 5 6* Primary Compute with four processor clusters, each containing: 7 8 * Four Cortex-A720AE cores (Armv9.2-A application processor, 64-bit mode) 9 * A DynamIQ Shared Unit (DSU-120AE) 10 11* A GIC-720AE, which is GICv4-compatible and supports GICv3 mode as well. 12 13Further information on RD-Aspen is available at `Zena CSS`_ 14 15Boot Sequence 16------------- 17 18The boot process begins with the Runtime Security Engine (RSE), which loads the 19Application Processor (AP) BL2 image into the Trusted SRAM at a fixed address. 20Once loaded, the RSE signals the System Control Processor firmware (SCP-firmware) 21running on Safety Island Cluster 0 (SI CL0) to initiate the AP power-up sequence. 22 23The SCP-firmware then sets the reset vector base address (RVBAR) for the AP, ensuring 24it starts executing BL2 from the designated address. Following this, the SCP-firmware 25powers on AP Cluster 0, allowing the AP to run AP BL2. 26 27The following tasks are executed for each AP BL stage: 28 291. AP BL2: 30 31 * Performs the actions described in the `Trusted Board Boot (TBB)`_ document. 32 * (Optional step) Find the FIP image in a GPT partition, incase the FIP lies 33 within in a GPT image. 34 * Copies the FW_CONFIG from Secure Flash to Trusted SRAM. 35 * (Optional step) Computes FW_CONFIG image measurement and invokes extend 36 operation of TF-M Measured Boot secure partition. 37 * Completes its dynamic configuration from the FW_CONFIG loaded. 38 This includes: 39 40 * Parsing the configuration data. 41 * Setting up the required system parameters. 42 43 * Reads and loads AP BL31 image into the Trusted SRAM. 44 * (Optional step) Computes AP BL31 image measurement and invokes extend operation of TF-M 45 Measured Boot secure partition 46 * Copies the HW_CONFIG from Secure Flash to DRAM. 47 * (Optional step) Computes HW_CONFIG (DTB) image measurement and invokes 48 extend operation of TF-M Measured Boot secure partition. 49 * (If present) Reads and loads AP BL32 (Secure Payload) image into Secure DRAM 50 * (Optional step, if present) Computes AP BL32 image measurement and invokes extend 51 operation of TF-M Measured Boot secure partition 52 * (If present) Reads and loads the SPMC manifest (for S-EL2 firmware configuration) 53 into Trusted SRAM and passes its location to BL31. 54 * Copies AP BL33 and Device tree blob from Secure Flash to Normal DRAM. 55 * (Optional step) Computes AP BL33 image measurement and invokes extend operation of TF-M 56 Measured Boot secure partition 57 * Transfers the execution to AP BL31. 58 592. AP BL31: 60 61 * Initializes Trusted Firmware-A Services. 62 * Transfers the execution to AP BL32 and then transfers the execution to AP BL33 63 643. AP BL32: 65 66 * Initializes Trusted OS (OP-TEE) environment 67 * Initializes Secure Partitions 68 * Transfers the execution back to AP BL31 69 * During runtime, it facilitates secure communication between the 70 normal world environment (e.g. Linux) and the Trusted Execution Environment. 71 72Build Procedure (TF-A only) 73--------------------------- 74 75- Ensure all `Prerequisites`_ are met, and the ``CROSS_COMPILE`` environment 76 variable is properly set. 77 78- Build TF-A: 79 80 81 .. code:: shell 82 83 make \ 84 PLAT=rdaspen \ 85 MBEDTLS_DIR=<mbedtls_dir> \ 86 CREATE_KEYS=1 \ 87 GENERATE_COT=1 \ 88 TRUSTED_BOARD_BOOT=1 \ 89 COT=tbbr \ 90 ARM_ROTPK_LOCATION=devel_rsa \ 91 ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem \ 92 BL32=<path to optee binary> \ 93 ARM_GPT_SUPPORT=1 \ 94 BL33=<PATH-TO-BL33-BINARY> \ 95 MEASURED_BOOT=1 \ 96 97.. note:: 98 99 The ``BL32`` flag is optional and should be set only if a Trusted OS is required. 100 If it is not set, then ``BL33`` will be loaded directly after ``BL31``. 101 102 The ``ARM_GPT_SUPPORT`` flag is also optional. It must be enabled when the 103 FIP image resides inside a GPT partition on Secure Flash. 104 105 The ``MEASURED_BOOT`` flag is also optional. It must be enabled in order to 106 enable measurement of FW images and data. 107 108-------------- 109 110*Copyright (c) 2025, Arm Limited. All rights reserved.* 111 112.. _Prerequisites: https://trustedfirmware-a.readthedocs.io/en/latest/getting_started/prerequisites.html 113.. _Trusted Board Boot (TBB): https://trustedfirmware-a.readthedocs.io/en/latest/design/trusted-board-boot.html 114.. _Zena CSS: https://www.arm.com/products/automotive/compute-subsystems/zena 115