Re: [PATCH v13 04/10] arm_ffa: introduce Arm FF-A support

[Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>]

Hi Simon,

On Tue, Jun 20, 2023 at 11:27:20AM +0100, Simon Glass wrote:
> <abdellatif.elkhlifi@arm.com> wrote:
> >
> > Add Arm FF-A support implementing Arm Firmware Framework for Armv8-A v1.0
> >
> > The Firmware Framework for Arm A-profile processors (FF-A v1.0) [1]
> > describes interfaces (ABIs) that standardize communication
> > between the Secure World and Normal World leveraging TrustZone
> > technology.
> >
> > This driver uses 64-bit registers as per SMCCCv1.2 spec and comes
> > on top of the SMCCC layer. The driver provides the FF-A ABIs needed for
> > querying the FF-A framework from the secure world.
> >
> > The driver uses SMC32 calling convention which means using the first
> > 32-bit data of the Xn registers.
> >
> > All supported ABIs come with their 32-bit version except FFA_RXTX_MAP
> > which has 64-bit version supported.
> >
> > Both 32-bit and 64-bit direct messaging are supported which allows both
> > 32-bit and 64-bit clients to use the FF-A bus.
> >
> > 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.
> >
> > Clients are able to probe then use the FF-A bus by calling the DM class
> > searching APIs (e.g: uclass_first_device).
> >
> > 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). This FF-A driver takes care of all the
> > interactions between Normal world and Secure World.
> >
> > The driver exports its operations to be used by upper layers.
> >
> > Exported operations:
> >
> > - ffa_partition_info_get
> > - ffa_sync_send_receive
> > - ffa_rxtx_unmap
> >
> > 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).
> >
> > For more details please refer to the driver documentation [2].
> >
> > [1]: https://developer.arm.com/documentation/den0077/latest/
> > [2]: doc/arch/arm64.ffa.rst
> >
> > Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > Cc: Tom Rini <trini@konsulko.com>
> > Cc: Simon Glass <sjg@chromium.org>
> > Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> > Cc: Jens Wiklander <jens.wiklander@linaro.org>
> > Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
> >
> > ---
> >
> > Changelog:
> > ===============
> >
> > v13:
> >
> > * doc minor change: specify in the readme that the user
> >    should call ffa_rxtx_unmap() driver operation to unmap
> >    the RX/TX buffers on demand.

Are you happy with this commit please ? May I add a Reviewed-by ?

Cheers
Abdellatif