> BTW, why is tap_set unsigned long instead of unsigned int?

Because we use bitmap functions on it, and those have all unsigned long
as arguments.

> And perhaps it should be moved from host to priv?

That would be great, but other tap_* variables are still used in
tmio_mmc_core.c. We maybe can refactor all tap handling into
renesas_sdhi_core.c meanwhile, but this is a seperate issue.