1#######
2RD-1 AE
3#######
4
5************
6Introduction
7************
8
9The **Arm Reference Design-1 AE**, or **RD-1 AE**, targets the Automotive
10segment and introduces the concept of a high-performance  Arm\ :sup:`®`
11Neoverse\ :sup:`TM` V3AE Application Processor (Primary Compute) system
12augmented with an Arm\ :sup:`®` Cortex\ :sup:`®`-R82AE based Safety Island for
13scenarios where additional system safety monitoring is required. The system
14includes a Runtime Security Engine (RSE) used for the secure boot of the system
15elements and the runtime Secure Services.
16
17The RSE is the root of trust chain. It is the first booting element when
18the system is powered up.
19
20The RSE flash is used to store the images of various components, including:
21
22* RSE BL2 image
23* RSE Runtime image
24* SCP RAM Firmware (SCP RAMFW) image
25* Safety Island Cluster 0 (SI CL0) image
26* Safety Island Cluster 1 (SI CL1) image
27* Safety Island Cluster 2 (SI CL2) image
28
29The RSE uses the application processor secure flash for:
30
31* Application Processor TF-A BL2 (AP BL2) image
32
33*********
34Boot Flow
35*********
36
37Major steps of the boot flow:
38
391. RSE BL1_1:
40
41   * Begins executing in place from ROM when the system is powered up
42   * Provisions RSE BL1_2 and various keys and other data from the provisioning
43     bundle to the OTP (This step only happens on the system's first boot)
44   * Copies the RSE BL1_2 image from the OTP to the SRAM
45   * Validates RSE BL1_2 against the hash stored in the OTP
46   * Transfers the execution to RSE BL1_2
47
482. RSE BL1_2:
49
50   * Copies the encrypted RSE BL2 image from the RSE flash into the SRAM
51   * Decrypts the RSE BL2 image
52   * Transfers the execution to RSE BL2
53
543. RSE BL2:
55
56   * Copies the SCP RAMFW image from the RSE flash to SCP SRAM and authenticates
57     the image
58   * Releases the SCP out of reset
59   * Copies the SI CL0 image from the RSE flash to SI LLRAM and authenticates
60     the image
61   * Notifies the SCP to power on the SI CL0
62   * Copies the SI CL1 image from the RSE flash to SI LLRAM and authenticates
63     the image
64   * Notifies the SCP to power on the SI CL1
65   * Copies the SI CL2 image from the RSE flash to SI LLRAM and authenticates
66     the image
67   * Notifies the SCP to power on the SI CL2
68   * Copies the AP BL2 image from the AP secure flash to AP SRAM and
69     authenticates the image
70   * Notifies the SCP to power on the AP
71
72*****
73Build
74*****
75
76The official method of building the platform binaries is using Yocto. Follow
77the instructions in `Arm Automotive Solutions User Guide`_.
78
79You can also build the platform by following the instructions in
80:doc:`Build instructions </building/tfm_build_instruction>` and building using
81platform name: `arm/rse/automotive_rd/rd1ae`
82``-DTFM_PLATFORM=arm/rse/automotive_rd/rd1ae``
83
84**************************************
85Arm Automotive Solutions Documentation
86**************************************
87
88For more information on **RD-1 AE**, refer to
89`Arm Automotive Solutions Documentation`_.
90
91.. note::
92
93    Not all the RSE features and implementation have been upstreamed to
94    Trusted Firmware-M yet.
95
96*Copyright (c) 2024, Arm Limited. All rights reserved.*
97
98.. _Arm Automotive Solutions Documentation: https://kronos-ref-stack.docs.arm.com/
99.. _Arm Automotive Solutions User Guide: https://arm-auto-solutions.docs.arm.com/en/v1.1.1/user_guide/index.html
100