Hello Krzysztof,
On 1/26/24 12:03, Krzysztof Kozlowski wrote:
On 18/01/2024 11:04, Arnaud Pouliquen wrote:
The "st,stm32mp1-m4-tee" compatible is utilized in a system configuration where the Cortex-M4 firmware is loaded by the Trusted execution Environment (TEE). For instance, this compatible is used in both the Linux and OP-TEE device-tree:
- In OP-TEE, a node is defined in the device tree with the st,stm32mp1-m4-tee to support signed remoteproc firmware. Based on DT properties, OP-TEE authenticates, loads, starts, and stops the firmware.
- On Linux, when the compatibility is set, the Cortex-M resets should not be declared in the device tree.
Signed-off-by: Arnaud Pouliquen arnaud.pouliquen@foss.st.com
V1 to V2 updates
- update "st,stm32mp1-m4" compatible description to generalize
- remove the 'reset-names' requirement in one conditional branch, as the property is already part of the condition test.
.../bindings/remoteproc/st,stm32-rproc.yaml | 52 +++++++++++++++---- 1 file changed, 43 insertions(+), 9 deletions(-)
diff --git a/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml index 370af61d8f28..6af821b15736 100644 --- a/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml +++ b/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml @@ -16,7 +16,12 @@ maintainers: properties: compatible:
- const: st,stm32mp1-m4
- enum:
- st,stm32mp1-m4- st,stm32mp1-m4-teeThe patch looks good to me, but I wonder about this choice of two compatibles.
Basically this is the same hardware with the same interface, but two compatibles to differentiate a bit different firmware setup. We have already such cases for Qualcomm [1] [2] and new ones will be coming. [3]
I wonder whether this should be rather the same compatible with additional property, e.g. "st,tee-control" or "remote-control".
Yes the point is valid, I asked myself the question.
I proposed a compatibility solution for one main reason. On the STM32MP15, if the firmware is loaded by Linux, no driver is probed in OP-TEE. But if the firmware is authenticated and loaded by OP-TEE, a Op-TEE driver is probed to manage memory access rights.
The drawback of a property is that we would need to probe the OP-TEE driver for the STM32MP1 platform even if it is not used, just to check this property.
Thanks, Arnaud
[1] https://elixir.bootlin.com/linux/v6.7.1/source/Documentation/devicetree/bind...
[2] https://elixir.bootlin.com/linux/v6.7.1/source/Documentation/devicetree/bind... (that's a bit different)
[3] https://lore.kernel.org/linux-devicetree/20240124103623.GJ4906@thinkpad/
@Rob, Any general guidance for this and Qualcomm?
Best regards, Krzysztof