[PATCH v20 0/6] Introduction of a remoteproc tee to load signed firmware

Arnaud Pouliquen
2025-12-17T15:40:10Z

Main updates from version V19[3]:
--------------------------------
The devicetree is now structured as follows:

firmware {
optee {
compatible = "linaro,optee-tz";
method = "smc";
#address-cells = <1>;
#size-cells = <0>;
rproc-service@0 {
compatible = "rproc-service-80a4c275-0a47-4905-8285-1486a9771a08";
reg = <0>;
#address-cells = <1>;
#size-cells = <0>;
status = "okay";
m4: m4@0 {
compatible = "st,stm32mp15-m4-tee";
reg = <0>;
mboxes = <&ipcc 0>, <&ipcc 1>, <&ipcc 2>;
mbox-names = "vq0", "vq1", "shutdown";
memory-region = <&vdev0vring0>, <&m_ipc_shm>, <&mcuram2>,
<&vdev0vring1>, <&vdev0buffer>, <&retram>;
interrupt-parent = <&exti>;
interrupts = <68 1>;
status = "okay";
};
};
};
};

As a consequence, this version:

- Introduces a new stm32_rproc_tee.c remoteproc driver.

Instead of further complicating the existing stm32_rproc.c driver, a
dedicated TEE-based driver is added. Both drivers are intended to also
support the STM32MP2x Cortex-M33 remote processor in a next step.

- Reworks the bindings:
- Drop the st,stm32-rproc.yaml updates that were introduced in previous
revisions.
- Add remoteproc-tee.yaml for the
"rproc-service-80a4c275-0a47-4905-8285-1486a9771a08" compatible.
- Add st,stm32-rproc-tee.yaml for the "st,stm32mp15-m4-tee" compatible.

- Reworks the probing sequence:

The m4@0 device is now probed by the remoteproc-tee driver, which itself
is instantiated by the TEE (OP-TEE) bus.

Main updates from version V18[2]:
--------------------------------
- rework documentation for the release_fw ops
- rework function documentation in remoteproc_tee.c
- replace spinlock by mutex and generalize usage in remoteproc_tee.c

Main updates from version V17[1]:
--------------------------------
- Fix: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h>
is missing

More details are available in each patch commit message.

[1] https://lore.kernel.org/linux-remoteproc/20250613091650.2337411-1-arnaud.pouliquen@foss.st.com/
[2] https://lore.kernel.org/linux-remoteproc/20250616075530.4106090-1-arnaud.pouliquen@foss.st.com/
[3] https://lore.kernel.org/linux-devicetree/20250625094028.758016-1-arnaud.pouliquen@foss.st.com/

Tested-on:
---------
commit 7d0a66e4bb90 ("Linux 6.18")

Description of the feature:
--------------------------
This series proposes the implementation of a remoteproc tee driver to
communicate with a TEE trusted application responsible for authenticating
and loading the remoteproc firmware image in an Arm secure context.

1) Principle:

The remoteproc tee driver provides services to communicate with the OP-TEE
trusted application running on the Trusted Execution Context (TEE).
The trusted application in TEE manages the remote processor lifecycle:

- authenticating and loading firmware images,
- isolating and securing the remote processor memories,
- supporting multi-firmware (e.g., TF-M + Zephyr on a Cortex-M33),
- managing the start and stop of the firmware by the TEE.

2) Format of the signed image:

Refer to:
https://github.com/OP-TEE/optee_os/blob/master/ta/remoteproc/src/remoteproc_core.c#L18-L57

3) OP-TEE trusted application API:

Refer to:
https://github.com/OP-TEE/optee_os/blob/master/ta/remoteproc/include/ta_remoteproc.h

4) OP-TEE signature script

Refer to:
https://github.com/OP-TEE/optee_os/blob/master/scripts/sign_rproc_fw.py

Example of usage:
sign_rproc_fw.py --in <fw1.elf> --in <fw2.elf> --out <signed_fw.sign> --key ${OP-TEE_PATH}/keys/default.pem

5) Impact on User space Application

No sysfs impact. The user only needs to provide the signed firmware image
instead of the ELF image.

For more information about the implementation, a presentation is available here
(note that the format of the signed image has evolved between the presentation
and the integration in OP-TEE).

https://resources.linaro.org/en/resource/6c5bGvZwUAjX56fvxthxds

Arnaud Pouliquen (6):
dt-bindings: firmware: Add TEE remoteproc service binding
dt-bindings: remoteproc: Add STM32 TEE-controlled rproc binding
remoteproc: core: Introduce rproc_pa_to_va helper
remoteproc: Introduce optional release_fw operation
remoteproc: Add TEE support
remoteproc: stm32: Add TEE-controlled STM32 driver

.../arm/firmware/linaro,optee-tz.yaml | 6 +
.../bindings/remoteproc/remoteproc-tee.yaml | 47 ++
.../remoteproc/st,stm32-rproc-tee.yaml | 100 +++
drivers/remoteproc/Kconfig | 10 +
drivers/remoteproc/Makefile | 3 +-
drivers/remoteproc/remoteproc_core.c | 52 ++
drivers/remoteproc/remoteproc_internal.h | 6 +
drivers/remoteproc/remoteproc_tee.c | 771 ++++++++++++++++++
drivers/remoteproc/stm32_rproc_tee.c | 526 ++++++++++++
include/linux/remoteproc.h | 6 +
include/linux/remoteproc_tee.h | 89 ++
11 files changed, 1615 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/remoteproc/remoteproc-tee.yaml
create mode 100644 Documentation/devicetree/bindings/remoteproc/st,stm32-rproc-tee.yaml
create mode 100644 drivers/remoteproc/remoteproc_tee.c
create mode 100644 drivers/remoteproc/stm32_rproc_tee.c
create mode 100644 include/linux/remoteproc_tee.h

base-commit: 7d0a66e4bb9081d75c82ec4957c50034cb0ea449
--
2.43.0