docs(rd1ae): add RD-1 AE documentation

Documenting RD-1 AE features, boot sequence, and build
procedure.

Signed-off-by: Divin Raj <divin.raj@arm.com>
Change-Id: Ie93438931e9ead42a2a6dd2d752d37bc06fa2e32

docs/plat/arm/automotive_rd/index.rst

@@ -0,0 +1,50 @@
+RD-1 AE (Kronos) Platform
+=========================
+
+Some of the features of the RD-1 AE platform referenced in TF-A include:
+
+- Neoverse-V3AE, Arm9.2-A application processor (64-bit mode)
+- A GICv4-compatible GIC-720AE
+
+Further information on RD1-AE is available at `rd1ae`_
+
+Boot Sequence
+-------------
+
+BL2 –> BL31 –> BL33
+
+The boot process starts from RSE (Runtime Security Engine) that loads the BL2 image
+and signals the System Control Processor (SCP) to power up the Application Processor (AP).
+The AP then runs BL2, which loads the rest of the images, including the runtime firmware
+BL31, and proceeds to execute it. Finally, it passes control to the non-secure world
+BL33 (u-boot).
+
+BL2 performs the actions described in the `Trusted Board Boot (TBB)`_ document.
+
+Build Procedure (TF-A only)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+-  Obtain `Arm toolchain`_ and set the CROSS_COMPILE environment variable to
+   point to the toolchain folder.
+
+-  Build TF-A:
+
+   .. code:: shell
+
+      make \
+      PLAT=rd1ae \
+      MBEDTLS_DIR=<mbedtls_dir> \
+      ARCH=aarch64 \
+      CREATE_KEYS=1 \
+      GENERATE_COT=1 \
+      TRUSTED_BOARD_BOOT=1 \
+      COT=tbbr \
+      ARM_ROTPK_LOCATION=devel_rsa \
+      ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem \
+      BL33=<path to u-boot binary> \
+
+*Copyright (c) 2024, Arm Limited. All rights reserved.*
+
+.. _Arm Toolchain: https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/downloads
+.. _rd1ae: https://developer.arm.com/Tools%20and%20Software/Arm%20Reference%20Design-1%20AE
+.. _Trusted Board Boot (TBB): https://trustedfirmware-a.readthedocs.io/en/latest/design/trusted-board-boot.html

docs/plat/arm/index.rst

@@ -14,6 +14,7 @@ Arm Development Platforms
    arm-build-options
    morello/index
    corstone1000/index
+   automotive_rd/index
 
 This chapter holds documentation related to Arm's development platforms,
 including both software models (FVPs) and hardware development boards
@@ -21,4 +22,4 @@ such as Juno.
 
 --------------
 
-*Copyright (c) 2019-2021, Arm Limited. All rights reserved.*
+*Copyright (c) 2019-2024, Arm Limited. All rights reserved.*