[PATCH v2 0/5] Add support for the TPM FF-A start method

From: Stuart Yoder
Date: Wed Feb 12 2025 - 17:06:34 EST


Firmware Framework for Arm A-profile (FF-A) is a messaging framework
for Arm-based systems, and in the context of the TPM CRB driver is used
to signal 'start' to a CRB-based TPM service which is hosted in an
FF-A secure partition running in TrustZone.

These patches add support for the CRB FF-A start method defined
in the TCG ACPI specification v1.4 and the FF-A ABI defined
in the Arm TPM Service CRB over FF-A (DEN0138) specification:
https://developer.arm.com/documentation/den0138/latest/

The first patch adds an FF-A driver to handle the FF-A messaging when
communicating with a CRB-based TPM secure partition built on FF-A.
The driver is probed when the TPM secure partition is discovered by
the Linux FF-A infrastructure.

The second patch consolidates the check for idle support in the CRB
driver to one place.

The third patch defines the new ACPI start method enumeration for
CRB over FF-A.

The fourth patch adds support for the FF-A ACPI start method to
the TPM crb driver.

The fifth patch adds documentation explaining how the CRB driver
and FF-A relate.

Version 2
-updates to cover letter to define FF-A
-added new patch with documentation
-created pull request in ACPIA and added link to the patch
updating actbl3.h
-added tpm_ prefix to the FF-A CRB driver

Stuart Yoder (5):
tpm_crb: implement driver compliant to CRB over FF-A
tpm_crb: refactor check for idle support into TPM into inline function
ACPICA: add start method for Arm FF-A
tpm_crb: add support for the Arm FF-A start method
Documentation: tpm: add documentation for the CRB FF-A interface

Documentation/security/tpm/tpm_ffa_crb.rst | 65 +++++
drivers/char/tpm/Kconfig | 9 +
drivers/char/tpm/Makefile | 1 +
drivers/char/tpm/tpm_crb.c | 81 +++++-
drivers/char/tpm/tpm_ffa_crb.c | 310 +++++++++++++++++++++
drivers/char/tpm/tpm_ffa_crb.h | 30 ++
include/acpi/actbl3.h | 1 +
7 files changed, 491 insertions(+), 6 deletions(-)
create mode 100644 Documentation/security/tpm/tpm_ffa_crb.rst
create mode 100644 drivers/char/tpm/tpm_ffa_crb.c
create mode 100644 drivers/char/tpm/tpm_ffa_crb.h

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2.34.1