[PATCH 2/2] ACPI: FFH: Support FF-A direct request 2 calls

[Sudeep Holla]

On Tue, Nov 03, 2026 at 02:53:35PM -0800, Jonathan Cameron wrote:
> On Tue,  3 Nov 2026 17:39:07 +0000
> Sudeep Holla <sudeep.holla at kernel.org> wrote:
> 
> > Arm Functional Fixed Hardware specification v1.3 defines FFH
> > OperationRegion offset 2 for issuing FFA_MSG_SEND_DIRECT_REQ2 calls.
> > The arm64 FFH handler currently supports only generic 32-bit and 64-bit
> > SMCCC calls, so it cannot implement this standardized interface.
> > 
> > Add a standalone FF-A path using the existing SMCCC conduit. Negotiate
> > FF-A v1.2, discover the sender endpoint with FFA_ID_GET, and use either
> > the receiver supplied by firmware or resolve a unique receiver from the
> > service UUID with FFA_PARTITION_INFO_GET_REGS.
> > 
> > Convert the ACPI ToUUID representation to the FF-A register encoding,
> > construct the direct request, resume interrupted or yielded calls with
> > FFA_RUN, and return the defined FFH status codes to AML.
> > 
> > Register-based partition discovery avoids RX/TX buffer ownership and
> > keeps the FFH implementation independent of the Arm FF-A transport
> > driver.
> > 
> > Signed-off-by: Sudeep Holla <sudeep.holla at kernel.org>
> Hi Sudeep,
> 
> I was curious so took a quick look. Some drive by comments inline.
> 

All good point, will be updated accordingly in the next version. Thanks
for the review.

-- 
Regards,
Sudeep