On Wed, Jan 25, 2023 at 07:48:17AM +0000, Sudeep Holla wrote: > On Tue, Jan 24, 2023 at 03:56:19PM +0000, Abdellatif El Khlifi wrote: > > > > I'd like to suggest the creation of a root node called arm_smccc as shown > > below. > > > > Not sure if U-Boot already supports the existing binding of PSCI and OPTEE. > > > This node is the parent of all nodes using SMC calls like FF-A, PSCI, > > optee, ... > > > > Well if you want to start with the clean slate for all new platforms, then > it is a good way. But you don't need any of the child nodes as they can all > be queried and discovered. > > > The first child to be integrated in the arm_smccc root node is FF-A. > > Hopefully, in the future the other features such as PSCI could be integrated > > under arm_smccc as well. > > > > You don't need FF-A or any other node if the presence of SMCCC node indicates > the support of SMCCC v1.1+(need to go back and check to confirm this). > You can query the presence of all the feature. There is no need to have a > node for each of the feature supported. That was the whole discussion of this > thread IIUC. > > -- > Regards, > Sudeep
Hi Simon, Rob, Sudeep I'm tweaking my previous suggestion regarding the creation of a new arm_smccc root node. This node is the parent of all SW features using SMC calls like FF-A, PSCI, optee, ... However, no child node is created in the DT. The SW features are seen as architecture features and can be discovered by querying through SMC calls. So, when probed the arm_smccc device driver tries to discover the SW features (FF-A, PSCI, optee, ...) by calling xxx_discover() API for each feature ( e.g: ffa_discover() ). The xxx_discover() creates U-Boot device(s) for the feature and set arm_smccc as the parent. "dm tree" command should show: SMCCC +--PSCI +--TRNG +--FF-A +--SCMI (sometimes) +--OP-TEE +--...Whatever Arm comes up with next... As Sudeep suggested, we only need this node: firmware { arm_smccc { compatible = "arm,smccc-1.2"; }; }; What do you think guys ? Are you happy with this approach ? Kind regards, Abdellatif