Overview
Trusted Firmware-A (TF-A) provides a reference implementation of secure world software for Armv7-A and Armv8-A, including a Secure Monitor executing at Exception Level 3 (EL3).
TF-A is the initial code on ARMv8-A cores for all K3 platforms. After setting up the initial core state and applying any needed errata fixes it sets up itself as the EL3 monitor handler. Following that, it installs the secure world open source Trusted Execution Environment (OP-TEE) software and passes execution on to either the Linux kernel or U-Boot in the non-secure world.
.. ifconfig:: CONFIG_part_variant in ('AM62LX')
.. rubric:: Power and Clock Management using SCMI
The AM62Lx System-on-Chip (SoC) utilizes the System Control and Management Interface
(SCMI) protocol to manage clocks and power domains. SCMI is a standardized interface for
system control and management, providing a common way to access and control system resources.
The SCMI IDs used in the AM62L TF-A implementation are documented in the
`TF-A documentation <https://github.com/TexasInstruments/arm-trusted-firmware/blob/ti-master/docs/plat/ti-am62l.rst>`__.
.. rubric:: SCMI and TI SCI
The AM62Lx represents a transition in Texas Instruments' approach to system control
interfaces. In the previous K3 devices, the Texas Instruments System Controller Interface (TI SCI)
was the primary protocol used for power, clock, and resource management. SCMI now serves
as a replacement for newer devices like the AM62L, offering similar functionality through
an industry-standard ARM protocol. This transition is in part due to the absence of any Device
Management (R5 core) in the AM62Lx.
.. rubric:: Implementation Overview
The AM62L TF-A implementation runs a SCMI server that manages:
* **Power Domains**: Over 100 power domains are defined for various peripherals and subsystems
* **Clock Management**: Extensive clock control for all major peripherals including:
- Multiple clock sources (PLLs, oscillators, external clocks)
- Clock multiplexers for flexible clock routing
- Clock dividers for frequency scaling
- Support for dynamic clock rate configuration
.. rubric:: Clock Infrastructure
The clock management system supports:
* **Parent Clock Selection** - Multiple clock sources can be selected as parents for each peripheral
* **Clock Multiplexing** - Dynamic switching between different clock sources
* **Rate Configuration** - Flexible frequency configuration within supported ranges
.. rubric:: Usage in Linux
Linux kernel drivers can use standard SCMI client APIs to:
* Request power state changes for devices
* Configure clock rates and parents
* Query current power and clock states
* Implement dynamic power management policies
Getting the TF-A Source Code
The pre-built TF-A binary is in the TI Processor SDK: <path-to-processor-sdk>/board-support/prebuilt-images/<optional-build-machine-name>/bl31.bin. Use this binary since it is tested with TI Processor SDK.
If it is not possible to use a pre-built binary, use the following:
.. ifconfig:: CONFIG_part_variant in ('AM62LX')
.. code-block:: console
$ git clone https://github.com/TexasInstruments/arm-trusted-firmware.git
$ git checkout <hash>
.. ifconfig:: CONFIG_part_variant not in ('AM62LX')
.. code-block:: console
$ git clone https://review.trustedfirmware.org/TF-A/trusted-firmware-a.git
$ git checkout <hash>
Where <hash> is the commit shown in :ref:`release-specific-build-information`.
Setup Cross Compile Environment
Building TF-A
.. ifconfig:: CONFIG_part_variant in ('AM62LX', 'AM62X', 'AM62AX', 'AM62PX', 'AM64X', 'J722S')
.. ifconfig:: CONFIG_part_variant in ('AM62X', 'AM62AX', 'AM62PX', 'AM64X', 'J722S')
.. code-block:: console
$ export TFA_DIR=<path-to-arm-trusted-firmware>
$ cd $TFA_DIR
$ make ARCH=aarch64 CROSS_COMPILE="$CROSS_COMPILE_64" PLAT=k3 TARGET_BOARD=lite SPD=opteed
.. ifconfig:: CONFIG_part_variant in ('AM62LX')
*Without OP-TEE enabled:*
.. code-block:: console
$ export TFA_DIR=<path-to-arm-trusted-firmware>
$ cd $TFA_DIR
$ make ARCH=aarch64 CROSS_COMPILE="$CROSS_COMPILE_64" PLAT=k3 TARGET_BOARD=am62l
.. ifconfig:: CONFIG_part_variant in ('J721S2')
.. code-block:: console
$ make CROSS_COMPILE="$CROSS_COMPILE_64" ARCH=aarch64 PLAT=k3 TARGET_BOARD=generic SPD=opteed K3_USART=0x8
.. ifconfig:: CONFIG_part_variant in ('J784S4','J742S2')
.. code-block:: console
$ make CROSS_COMPILE="$CROSS_COMPILE_64" ARCH=aarch64 PLAT=k3 TARGET_BOARD=j784s4 SPD=opteed K3_USART=0x8
.. ifconfig:: CONFIG_part_variant not in ('AM64X', 'AM62X', 'AM62LX', 'AM62AX', 'AM62PX', 'J721S2', 'J784S4', 'J742S2', 'J722S')
.. code-block:: console
$ make CROSS_COMPILE="$CROSS_COMPILE_64" PLAT=k3 TARGET_BOARD=generic SPD=opteed
Default load locations
.. ifconfig:: CONFIG_part_family in ('AM64X_family')
.. code-block:: text
+---------------------------+------------+
| TF-A image | 0x701c0000 |
+---------------------------+------------+
| OP-TEE image | 0x9e800000 |
+---------------------------+------------+
| U-Boot/Linux kernel image | 0x80080000 |
+---------------------------+------------+
| DTB | 0x82000000 |
+---------------------------+------------+
.. ifconfig:: CONFIG_part_family in ('AM62LX_family')
.. code-block:: text
+---------------------------+------------+
| TF-A image | 0x80000000 |
+---------------------------+------------+
| OP-TEE image | 0x80200000 |
+---------------------------+------------+
| U-Boot/Linux kernel image | 0x80080000 |
+---------------------------+------------+
| DTB | 0x82000000 |
+---------------------------+------------+
.. ifconfig:: CONFIG_part_family not in ('AM64X_family', 'AM62LX_family')
.. code-block:: text
+---------------------------+------------+
| TF-A image | 0x70000000 |
+---------------------------+------------+
| OP-TEE image | 0x9e800000 |
+---------------------------+------------+
| U-Boot/Linux kernel image | 0x80080000 |
+---------------------------+------------+
| DTB | 0x82000000 |
+---------------------------+------------+
.. ifconfig:: CONFIG_part_variant in ('AM64X', 'AM62X', 'AM62AX', 'AM62PX', 'J722S')
To change the default load address of these binaries, an address has to be changed in several source trees. The following
is an example for AM64x family devices. Other family devices might not at the moment have binman dtsi files associated with
them but they could in the future.
.. code-block:: text
+-----------------------------------------------------+------------------+-----------------------+---------------------+---------------+-------------------+----------+----------------------------------------+
| Source | TF-A | OPTEE | A53 SPL | A53 U-Boot | DTB | kernel | Comments |
+=====================================================+==================+=======================+=====================+===============+===================+==========+========================================+
| <atf>/plat/ti/k3/board/lite/board.mk | | BL32_BASE | PRELOADED_BL33_BASE | | K3_HW_CONFIG_BASE | | Change K3_HW_CONFIG_BASE for |
| | | | | | | | u-boot a53 skip case |
+-----------------------------------------------------+------------------+-----------------------+---------------------+---------------+-------------------+----------+----------------------------------------+
| <optee>/core/arch/arm/plat-k3/conf.mk | | CFG_TZDRAM_START | | | | | |
+-----------------------------------------------------+------------------+-----------------------+---------------------+---------------+-------------------+----------+----------------------------------------+
| <uboot>/configs/am64x_evm_r5_defconfig | K3_ATF_LOAD_ADDR | | | | | | |
+-----------------------------------------------------+------------------+-----------------------+---------------------+---------------+-------------------+----------+----------------------------------------+
| <uboot>/configs/am64x_evm_a53_defconfig | | | SPL_TEXT_BASE | SYS_TEXT_BASE | | | SYS_TEXT_BASE can be set in defconfig, |
| | | | | | | | has default value in Kconfig |
+-----------------------------------------------------+------------------+-----------------------+---------------------+---------------+-------------------+----------+----------------------------------------+
| <uboot/linux>/arch/arm/dts/k3-am642*.dts files | | reserved-memory nodes | | | | | |
+-----------------------------------------------------+------------------+-----------------------+---------------------+---------------+-------------------+----------+----------------------------------------+
| <uboot>/arch/arm/dts/k3-am642-evm-binman.dtsi file | | tee nodes | uboot nodes | uboot nodes | | | |
+-----------------------------------------------------+------------------+-----------------------+---------------------+---------------+-------------------+----------+----------------------------------------+
| <uboot>/include/configs/ti_armv7_common.h | | | | | fdtaddr | loadaddr | If not defined here, u-boot |
| | | | | | | | will pick any adress |
+-----------------------------------------------------+------------------+-----------------------+---------------------+---------------+-------------------+----------+----------------------------------------+
| uEnv.txt | | | | | fdtaddr | loadaddr | Overwrite the u-boot environment |
| | | | | | | | variables |
+-----------------------------------------------------+------------------+-----------------------+---------------------+---------------+-------------------+----------+----------------------------------------+