Re: [PATCH v22 0/7] Introduction of a remoteproc tee to load signed firmware

[Arnaud POULIQUEN <arnaud.pouliquen@foss.st.com>]

Hello,

Just a gentle reminder: as a first step, I would appreciate it if we 
could at least finalize the discussion on the bindings based on phandles.

Thanks,
Arnaud

On 4/14/26 17:28, Arnaud Pouliquen wrote:
> Main updates from version V21[1]:
> --------------------------------
> This version removes the st,stm32mp1-m4-tee compatibility string,
> which no longer seems to be accepted by the Devicetree maintainers.
> As a consequence, the stm32-rproc-tee driver, introduced to simplify
> the code, is removed. The STM32 integration reuses the existing
> stm32_rproc driver implemented in V19.
> 
> The devicetree is now structured as follows:
> 
>      firmware {
>          tee_rproc: optee-rproc {
>              compatible = "80a4c275-0a47-4905-8285-1486a9771a08";
>          };
>      };
> 
>      m4: m4@10000000 {
>        compatible = "st,stm32mp1-m4";
>        reg = <0x10000000 0x40000>,
>              <0x30000000 0x40000>,
>              <0x38000000 0x10000>;
> 
>        mboxes = <&ipcc 0>, <&ipcc 1>, <&ipcc 2>, <&ipcc 3>;
>        mbox-names = "vq0", "vq1", "shutdown", "detach";
> 
>        memory-region = <&vdev0vring0>, <&m_ipc_shm>, <&mcuram2>,
>                        <&vdev0vring1>, <&vdev0buffer>, <&retram>;
> 
>        interrupt-parent = <&exti>;
>        interrupts = <68 1>;
> 
>        st,rproc-tee = <&tee_rproc 0>;
> 
>        status = "okay";
>      };
> 
> As a consequence, this version:
> - reintroduce v19 commits for stm32_rproc.c driver , adding the support
>    of the st,rproc-tee binding.
> - drops the dedicated remoteproc-tee.yaml and st,stm32-rproc-tee.yaml
>    bindings from the series.
> - extends st,stm32-rproc.yaml with st,rproc-tee to describe the link to
>    the TEE remoteproc backend.
> - removes the dedicated stm32_rproc_tee.c driver and reuses stm32_rproc.c
>    for both native and TEE-controlled cases.
> - keeps remoteproc_tee.c aligned with the phandle-based lookup introduced
>    in v21 and uses a device_link between the STM32 remoteproc instance and
>    the TEE backend device.
> 
> More details are available in each patch commit message.
> 
> Main updates from version V20[3]:
> --------------------------------
> To address Rob’s concern on v20concerning resource declaration under the
> tee node, the device tree is now structured as follows,replacing the
> child-parent hierarchy with a phandle:
> 
>      firmware {
>          tee_rproc: optee-rproc {
>              compatible = "80a4c275-0a47-4905-8285-1486a9771a08";
>          };
>      };
> 
>      m4: m4@0 {
>        compatible = "st,stm32mp1-m4-tee";
>        reg = <0 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>;
> 
>        rproc-tee-phandle = <&tee_rproc 0>;
>        st,auto-boot;
>        wakeup-source;
> 
>        status = "okay";
>      };
> 
> As a consequence, this version:
> - Updates the device tree and bindings to:
>    - Change the compatible property from
>      "rproc-service-80a4c275-0a47-4905-8285-1486a9771a08" to
>      "80a4c275-0a47-4905-8285-1486a9771a08".
>    - Use the rproc-tee-phandle to avoid the parent-child hierarchy.
> - Updates stm32_rproc_tee.c and remoteproc_tee.c to adapt to the new bindings.
> - Updates remoteproc_tee.c to compute the device tree compatible string from
>    the TEE UUID.
> 
> Main updates from version V19[4]:
> --------------------------------
> 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.
> 
> More details are available in each patch commit message.
> 
> [1] https://lore.kernel.org/linux-remoteproc/20260317180329.1207625-1-arnaud.pouliquen@foss.st.com/
> [2] https://lore.kernel.org/linux-remoteproc/20251217153917.3998544-1-arnaud.pouliquen@foss.st.com/
> [3] https://lore.kernel.org/linux-devicetree/20250625094028.758016-1-arnaud.pouliquen@foss.st.com/
> 
> 
> Tested-on:
> ---------
> commit 591cd656a1bf ("Linux 7.0-rc7")
> 
> 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 (7):
>    dt-bindings: firmware: Add TEE remoteproc service binding
>    dt-bindings: remoteproc: st,stm32-rproc: add st,rproc-tee
>    remoteproc: core: Introduce rproc_pa_to_va helper
>    remoteproc: Introduce optional release_fw operation
>    remoteproc: Add TEE support
>    remoteproc: stm32: Create sub-functions to request shutdown and
>      release
>    remoteproc: stm32: Add support of an OP-TEE TA to load the firmware
> 
>   .../bindings/remoteproc/remoteproc-tee.yaml   |  36 +
>   .../bindings/remoteproc/st,stm32-rproc.yaml   |  55 +-
>   drivers/remoteproc/Kconfig                    |  10 +
>   drivers/remoteproc/Makefile                   |   1 +
>   drivers/remoteproc/remoteproc_core.c          |  56 ++
>   drivers/remoteproc/remoteproc_internal.h      |   6 +
>   drivers/remoteproc/remoteproc_tee.c           | 789 ++++++++++++++++++
>   drivers/remoteproc/stm32_rproc.c              | 249 ++++--
>   include/linux/remoteproc.h                    |   6 +
>   include/linux/remoteproc_tee.h                |  98 +++
>   10 files changed, 1220 insertions(+), 86 deletions(-)
>   create mode 100644 Documentation/devicetree/bindings/remoteproc/remoteproc-tee.yaml
>   create mode 100644 drivers/remoteproc/remoteproc_tee.c
>   create mode 100644 include/linux/remoteproc_tee.h
> 
> 
> base-commit: 591cd656a1bf5ea94a222af5ef2ee76df029c1d2