Re: [PATCH v19 0/9] introduce Arm FF-A support

On Fri, Aug 04, 2023 at 02:33:36PM +0100, Abdellatif El Khlifi wrote:

Adding support for Arm FF-A v1.0 (Arm Firmware Framework for Armv8-A) [A].

FF-A specifies interfaces that enable a pair of software execution environments aka partitions to communicate with each other. A partition could be a VM in the Normal or Secure world, an application in S-EL0, or a Trusted OS in S-EL1.

FF-A is a discoverable bus and similar to architecture features. FF-A bus is discovered using ARM_SMCCC_FEATURES mechanism performed by the PSCI driver.

=> dm tree

Class     Index  Probed  Driver                Name

---

... firmware 0 [ + ] psci |-- psci ffa 0 [ ] arm_ffa | `-- arm_ffa ...

Clients are able to probe then use the FF-A bus by calling the DM class searching APIs (e.g: uclass_first_device).

This implementation of the specification provides support for Aarch64.

The FF-A driver uses the SMC ABIs defined by the FF-A specification to:

- Discover the presence of secure partitions (SPs) of interest
- Access an SP's service through communication protocols
  (e.g: EFI MM communication protocol)

The FF-A support provides the following features:

- Being generic by design and can be used by any Arm 64-bit platform
- FF-A support can be compiled and used without EFI
- Support for SMCCCv1.2 x0-x17 registers
- Support for SMC32 calling convention
- Support for 32-bit and 64-bit FF-A direct messaging
- Support for FF-A MM communication (compatible with EFI boot time)
- Enabling FF-A and MM communication in Corstone1000 platform as a use case
- A Uclass driver providing generic FF-A methods.
- An Arm FF-A device driver providing Arm-specific methods and reusing the Uclass methods.
- A sandbox emulator for Arm FF-A, emulates the FF-A side of the Secure World and provides
  FF-A ABIs inspection methods.
- An FF-A sandbox device driver for FF-A communication with the emulated Secure World.
  The driver leverages the FF-A Uclass to establish FF-A communication.
- Sandbox FF-A test cases.
- A new command called armffa is provided as an example of how to access the
  FF-A bus

For more details about the FF-A support please refer to [B] and refer to [C] for how to use the armffa command.

Please find at [D] an example of the expected boot logs when enabling FF-A support for a platform. In this example the platform is Corstone1000. But it can be any Arm 64-bit platform.

For the series, applied to u-boot/master, thanks!