Why

This function takes an offset and a length as argument, not a physical address and a number of pages.

This misuse caused the set_memory_*() and arch_io_reserve_memtype_wc() functions to return EINVAL.

Another problem was the fact that they returned errors as a positive integer, whereas Linux uses negative integers.

How

Physical addresses and number of pages are converted to offset+length in the set_memory_*() functions.

arch_io_reserve_memtype_wc() now calls pmap_change_attr() directly instead of using set_memory_wc().