Hi Julien, On Sat, Feb 12, 2022 at 12:43:56PM +0000, Julien Grall wrote: > Hi, > > On 11/02/2022 11:18, Bertrand Marquis wrote: > > Do you plan to add support for other boards ? > > > > Did you discuss more in general with the linux kernel guys to see if this > > approach was agreed and will be adopted by other manufacturers ? > > > > All in all I think this is a good idea but I fear that all this will > > actually only > > be used by one board or one manufacturer and other might use a different > > strategy, I would like to unrisk this before merging this in Xen. > > In the past we merged code that would only benefits one vendor (i.e. EEMI). > That said, this was a vendor specific protocol. I believe the situation is > different here because the spec is meant to be generic. > > > @julien and Stefano: what is your view here ? > > I share the same concerns as you. I think we need to make sure all the > pieces we rely on (e.g. firmware, DT bindings) have been agreed before we > can merge such code in Xen. > > The first step is to have all the pieces available in public so they can be > reviewed and tested together. > > Oleksii, on a separate e-mail, you said you made change for ATF. How much of > those changes was related to support for Xen? If they are some, then I think > they should be upstreamed first. >
Let me share changes, that were done to AT-F and Linux kernel device-tree in terms of the SCMI mediator POC. Changes to the Linux kernel: https://github.com/oleksiimoisieiev/arm-trusted-firmware/pull/4 Based on renesas-rcar linux-bsp, branch v5.10/rcar-5.0.0.rc5 Changes to AT-F: https://github.com/oleksiimoisieiev/linux-bsp/pull/3 Based on renesas-rcar/arm-trusted-firmware branch rcar_gen3_v2.5. All changes that were done are not Xen specific. Given AT-F changes are the implementation of the SCMI feature using SMC as transport. All changes were done accoding to the DEN0056C [0] and DEN0028D [1]. We pass channel_id via SMC to the Firmware on r7 bits [15:0] (See Section 4.1 of [1]). Then Firmware converts channel_id to agent_id. Channel_id can't be equal to agent_id in our case, because, according to the 4.2.2.8 of [0] - agent_id 0 is reserved to identify platform itself. [0] https://developer.arm.com/documentation/den0056/latest [1] https://developer.arm.com/documentation/den0028/latest Best regards, Oleksii.
