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 * Copies the FW_CONFIG from Secure Flash to Trusted SRAM. 33 * Completes its dynamic configuration from the FW_CONFIG loaded. 34 This includes: 35 36 * Parsing the configuration data. 37 * Setting up the required system parameters. 38 39 * Reads and loads AP BL31 image into the Trusted SRAM. 40 * Copies AP BL33 and Device tree blob from Secure Flash to Normal DRAM. 41 * Transfers the execution to AP BL31. 42 432. AP BL31: 44 45 * Initializes Trusted Firmware-A Services. 46 * Transfers the execution to AP BL33. 47 48Build Procedure (TF-A only) 49--------------------------- 50 51- Ensure all `Prerequisites`_ are met, and the ``CROSS_COMPILE`` environment 52 variable is properly set. 53 54- Build TF-A: 55 56 .. code:: shell 57 58 make \ 59 PLAT=rdaspen \ 60 MBEDTLS_DIR=<mbedtls_dir> \ 61 CREATE_KEYS=1 \ 62 GENERATE_COT=1 \ 63 TRUSTED_BOARD_BOOT=1 \ 64 COT=tbbr \ 65 ARM_ROTPK_LOCATION=devel_rsa \ 66 ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem \ 67 BL33=<PATH-TO-BL33-BINARY> \ 68 69-------------- 70 71*Copyright (c) 2025, Arm Limited. All rights reserved.* 72 73.. _Prerequisites: https://trustedfirmware-a.readthedocs.io/en/latest/getting_started/prerequisites.html 74.. _Trusted Board Boot (TBB): https://trustedfirmware-a.readthedocs.io/en/latest/design/trusted-board-boot.html 75.. _Zena CSS: https://www.arm.com/products/automotive/compute-subsystems/zena 76