Hi Arnaud, First of all apologies for such a late review comment as previously I wasn't CCed or involved in the review of this patch-set. In case any of my following comments have been discussed in the past then feel free to point me at relevant discussions.
On Wed, Jun 25, 2025 at 11:40:26AM +0200, 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). Having a DT based compatible for a TEE service to me just feels like it is redundant here. I can see you have also used a TEE bus based device too but that is not being properly used. I know subsystems like remoteproc, SCMI and others heavily rely on DT to hardcode properties of system firmware which are rather better to be discovered dynamically. So I have an open question for you and the remoteproc subsystem maintainers being: Is it feasible to rather leverage the benefits of a fully discoverable TEE bus rather than relying on platform bus/ DT to hardcode firmware properties? > > For instance, this compatible is used in both the Linux and OP-TEE device > trees: > - In OP-TEE, a node is defined in the device tree with the > "st,stm32mp1-m4-tee" compatible to support signed remoteproc firmware. > Based on DT properties, the OP-TEE remoteproc framework is initiated to > expose a trusted application service to authenticate and load the remote > processor firmware provided by the Linux remoteproc framework, as well > as to start and stop the remote processor. > - In Linux, when the compatibility is set, the Cortex-M resets should not > be declared in the device tree. In such a configuration, the reset is > managed by the OP-TEE remoteproc driver and is no longer accessible from > the Linux kernel. > > Associated with this new compatible, add the "st,proc-id" property to > identify the remote processor. This ID is used to define a unique ID, > common between Linux, U-Boot, and OP-TEE, to identify a coprocessor. This "st,proc-id" is just one such property which can rather be directly probed from the TEE/OP-TEE service rather than hardcoding it in DT here. I think the same will apply to other properties as well. -Sumit > This ID will be used in requests to the OP-TEE remoteproc Trusted > Application to specify the remote processor. > > Signed-off-by: Arnaud Pouliquen <[email protected]> > Reviewed-by: Rob Herring (Arm) <[email protected]> > --- > .../bindings/remoteproc/st,stm32-rproc.yaml | 58 ++++++++++++++++--- > 1 file changed, 50 insertions(+), 8 deletions(-) > > diff --git a/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml > b/Documentation/devicetree/bindings/remoteproc/st,stm32-rproc.yaml > index 843679c557e7..58da07e536fc 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-tee > + description: > + Use "st,stm32mp1-m4" for the Cortex-M4 coprocessor management by > non-secure context > + Use "st,stm32mp1-m4-tee" for the Cortex-M4 coprocessor management by > secure context > > reg: > description: > @@ -43,6 +48,10 @@ properties: > - description: The offset of the hold boot setting register > - description: The field mask of the hold boot > > + st,proc-id: > + description: remote processor identifier > + $ref: /schemas/types.yaml#/definitions/uint32 > + > st,syscfg-tz: > deprecated: true > description: > @@ -146,21 +155,43 @@ properties: > required: > - compatible > - reg > - - resets > > allOf: > - if: > properties: > - reset-names: > - not: > - contains: > - const: hold_boot > + compatible: > + contains: > + const: st,stm32mp1-m4 > then: > + if: > + properties: > + reset-names: > + not: > + contains: > + const: hold_boot > + then: > + required: > + - st,syscfg-holdboot > + else: > + properties: > + st,syscfg-holdboot: false > + required: > + - reset-names > required: > - - st,syscfg-holdboot > - else: > + - resets > + > + - if: > + properties: > + compatible: > + contains: > + const: st,stm32mp1-m4-tee > + then: > properties: > st,syscfg-holdboot: false > + reset-names: false > + resets: false > + required: > + - st,proc-id > > additionalProperties: false > > @@ -192,5 +223,16 @@ examples: > st,syscfg-rsc-tbl = <&tamp 0x144 0xFFFFFFFF>; > st,syscfg-m4-state = <&tamp 0x148 0xFFFFFFFF>; > }; > + - | > + #include <dt-bindings/reset/stm32mp1-resets.h> > + m4@10000000 { > + compatible = "st,stm32mp1-m4-tee"; > + reg = <0x10000000 0x40000>, > + <0x30000000 0x40000>, > + <0x38000000 0x10000>; > + st,proc-id = <0>; > + st,syscfg-rsc-tbl = <&tamp 0x144 0xFFFFFFFF>; > + st,syscfg-m4-state = <&tamp 0x148 0xFFFFFFFF>; > + }; > > ... > -- > 2.25.1 > >
