Hi Arnd, Thanks for the reply and guidance! On Fri, Sep 22, 2023, at 06:24:00 -0400, Arnd Bergmann wrote: > On Wed, Sep 13, 2023, at 17:49, Brad Larson wrote: >> The Pensando SoC controller is a SPI connected companion device >> that is present in all Pensando SoC board designs. The essential >> board management registers are accessed on chip select 0 with >> board mgmt IO support accessed using additional chip selects. >> >> Signed-off-by: Brad Larson <blarson@xxxxxxx> >> --- >> >> v15 changes: >> - Drop custom ioctl and use existing miscdevice interface. >> - Delete unused definitions in amd-pensando-ctrl.h >> - Makefile change to compile for ARCH_PENSANDO > > Hi Brad, > > I'm sorry I've been out of the loop for so long, and I hope > we can find a way to manage your SoC support soon. My impression > is that the normal support patches (1, 3, 4, and 5) are largely > uncontroversial, while the SoC controller support seems like > we are still not converging onto something that is ready to > merge, so I would suggest you split the two parts and send > the basic support for inclusion in linux-6.7 while we continue > to discuss the soc controller driver. I've sent a patchset with only patches 1, 3, 4, and 5. Correctness is the priority for upstream inclusion. > Please remove any references to the soc controller from the > dts files and send that first series to:soc@xxxxxxxxxx > cc:linux-arm-kernel (and the other interested parties) so > I can pick those up. Yes, I've removed the node for which the compatible driver is the problem. > > Regarding the soc controller driver, let me try to give > you my impression of where we are: > > - you have gone through 16 revisions already, which is way > too much for a public review, we should have been able > to find a solution earlier than that, and this is partly > our fault on the reviewer side, and I'm sorry about that. > > - Andy's latest comments and a lot of the earlier reviews > were focused on implementation details. While those comments > are helpful suggestions for improving the code, they miss > the larger point about the system design that I'm worried > about and probably don't help you actually get it merged. > > - The main problem I still see is that this driver completely > bypasses our normal kernel abstractions and instead creates > a low-level passthrough interface for handling kernel > functionality in userspace. This creates a liability both > for the user ABI and the kernel implementation and prevents > any > > - There is a chance that your design is in fact the > best way to handle this particular hardware, but it is > your job to write a convincing explanation of why this > platform is different from all the others in the patch > description. Your current one-paragraph text does not > explain this at all. > > I would suggest you prioritize getting the other patches > included for the moment, but we can keep discussion the > API design for this driver either in this thread or on the > #armlinux IRC channel (irc.libera.chat) in parallel if you > like. In order to help you here, I would need either > the documentation of the SPI software interface, or the > source code for the userspace tool. > > Arnd I'll redirect and reframe what the SoC driver is doing to #armlinux IRC to find an appropriate solution. Regards, Brad
