Hello, I'm working with a student to get NetBSD working on the SiFive HiFive Unleashed board. I know this is no longer being made, but we have one. He has the kernel running on the board until it wants to mount root. We want to get a sd driver working. The issue is that the sd device is on the spi bus on that hardware and sdmmc doesn't work on the spi bus.
We want to figure out how to connect the sdmmc to the spi bus. We have tried a number of things in the config framework to get sdmmc connected, but we don't know the internals of config well enough and we have not found any prior work that will help us get that done. Can anyone help us with the config framework and what is needed to get sdmmc to talk to the spi bus? I'm presuming that we'll need something in the dev/spi/files.spi, but haven't figured out what to say to get it to work. And I'm assuming there is a .c file that needs to implement the interface between the sdmmc and the spi, but I'm not sure. Do we need something in another place? Pointers to examples and/or documentation would be appreciated. Thanks. --Phil