On Mon, 25 Mar 2024 at 11:13, Abdellatif El Khlifi <abdellatif.elkhl...@arm.com> wrote: > > Hi Mathieu, > > > > > > > > > > This is an initial patchset for allowing to turn on and off > > > > > > > > > the remote processor. > > > > > > > > > The FW is already loaded before the Corstone-1000 SoC is > > > > > > > > > powered on and this > > > > > > > > > is done through the FPGA board bootloader in case of the FPGA > > > > > > > > > target. Or by the Corstone-1000 FVP model > > > > > > > > > (emulator). > > > > > > > > > > > > > > > > > >From the above I take it that booting with a preloaded > > > > > > > > >firmware is a > > > > > > > > scenario that needs to be supported and not just a temporary > > > > > > > > stage. > > > > > > > > > > > > > > The current status of the Corstone-1000 SoC requires that there is > > > > > > > a preloaded firmware for the external core. Preloading is done > > > > > > > externally > > > > > > > either through the FPGA bootloader or the emulator (FVP) before > > > > > > > powering > > > > > > > on the SoC. > > > > > > > > > > > > > > > > > > > Ok > > > > > > > > > > > > > Corstone-1000 will be upgraded in a way that the A core running > > > > > > > Linux is able > > > > > > > to share memory with the remote core and also being able to > > > > > > > access the remote > > > > > > > core memory so Linux can copy the firmware to. This HW changes > > > > > > > are still > > > > > > > This is why this patchset is relying on a preloaded firmware. And > > > > > > > it's the step 1 > > > > > > > of adding remoteproc support for Corstone. > > > > > > > > > > > > > > > > > > > Ok, so there is a HW problem where A core and M core can't see each > > > > > > other's > > > > > > memory, preventing the A core from copying the firmware image to > > > > > > the proper > > > > > > location. > > > > > > > > > > > > When the HW is fixed, will there be a need to support scenarios > > > > > > where the > > > > > > firmware image has been preloaded into memory? > > > > > > > > > > No, this scenario won't apply when we get the HW upgrade. No need for > > > > > an > > > > > external entity anymore. The firmware(s) will all be files in the > > > > > linux filesystem. > > > > > > > > > > > > > Very well. I am willing to continue with this driver but it does so > > > > little that > > > > I wonder if it wouldn't simply be better to move forward with > > > > upstreaming when > > > > the HW is fixed. The choice is yours. > > > > > > > > > > I think Robin has raised few points that need clarification. I think it > > > was > > > done as part of DT binding patch. I share those concerns and I wanted to > > > reaching to the same concerns by starting the questions I asked on > > > corstone > > > device tree changes. > > > > > > > I also agree with Robin's point of view. Proceeding with an initial > > driver with minimal functionality doesn't preclude having complete > > bindings. But that said and as I pointed out, it might be better to > > wait for the HW to be fixed before moving forward. > > We checked with the HW teams. The missing features will be implemented but > this will take time. > > The foundation driver as it is right now is still valuable for people wanting > to > know how to power control Corstone external systems in a future proof manner > (even in the incomplete state). We prefer to address all the review comments > made so it can be merged. This includes making the DT binding as complete as > possible as you advised. Then, once the HW is ready, I'll implement the comms > and the FW reload part. Is that OK please ? >
I'm in agreement with that plan as long as we agree the current preloaded heuristic is temporary and is not a valid long term scenario. > Cheers, > Abdellatif
