| # SPDX-License-Identifier: GPL-2.0 |
| |
| config ARM_FFA_TRANSPORT |
| bool "Enable Arm Firmware Framework for Armv8-A driver" |
| depends on DM && (ARM64 || SANDBOX) |
| select ARM_SMCCC if !SANDBOX |
| select ARM_SMCCC_FEATURES if !SANDBOX |
| imply CMD_ARMFFA |
| select LIB_UUID |
| select DEVRES |
| help |
| The Firmware Framework for Arm A-profile processors (FF-A) |
| describes interfaces (ABIs) that standardize communication |
| between the Secure World and Normal World leveraging TrustZone |
| technology. |
| |
| The FF-A support in U-Boot is based on FF-A specification v1.0 and uses SMC32 |
| calling convention. |
| |
| FF-A specification: |
| |
| https://developer.arm.com/documentation/den0077/a/?lang=en |
| |
| In U-Boot FF-A design, FF-A is considered as a discoverable bus. |
| FF-A bus is discovered using ARM_SMCCC_FEATURES mechanism performed |
| by the PSCI driver. |
| The Secure World is considered as one entity to communicate with |
| using the FF-A bus. |
| FF-A communication is handled by one device and one instance (the bus). |
| The FF-A support on U-Boot takes care of all the interactions between Normal |
| world and Secure World. |
| |
| Generic FF-A methods are implemented in the Uclass (arm-ffa-uclass.c). |
| Arm specific methods are implemented in the Arm driver (arm-ffa.c). |
| |
| FF-A sandbox is provided to run FF-A under sandbox and allows to test the FF-A Uclass. |
| Sandbox support includes an emulator for Arm FF-A which emulates the FF-A side of |
| the Secure World and provides FF-A ABIs inspection methods (ffa-emul-uclass.c). |
| An FF-A sandbox driver is also provided for FF-A communication with the emulated |
| Secure World (sandbox_ffa.c). |
| |
| For more details about the FF-A support, please refer to doc/arch/arm64.ffa.rst |