On Fri, Jul 24, 2020 at 03:35:47PM +0200, Arnd Bergmann wrote: > Starting simple is generally a good idea, yes. > > It would be good to have feedback from the nvme driver maintainers. > > One way I can see the handshake working would be to have > an sdexpress class_driver that provides interfaces for both mmc > and nvme to link against. The mmc core can then create a > class device when it finds an sd-express device and that > class device contains a simple state machine that keeps track of > what either side think is going on, possibly also providing > a way to perform callbacks between the two sides. None of this is in scope for the NVMe spec, so I don't really want to deal with it in the NVMe driver in any way. Given that a SD express card just turns into a normal PCIe link if you really want to check that something probed I think you'd want to track if any PCIe driver is bound to the device. Or just wait and see if we really need anything after all.
