Register Address Size Mismatch

[Farhan Khan]

I am working on porting over a Linux Realtek driver to FreeBSD. I ran
into a register-size issue.

FreeBSD's PCI-write function is defined as follows:
rtwn_pci_write_4(struct rtwn_softc *sc, uint16_t addr)

Notice that the second parameter is of type uint16_t.

During initialization, the rtwn driver uses the rtwn_rf_prog structure
to write a pre-defined list of data to a pre-defined list of registers.
The structure to hold both lists is defined here:
http://src.illumos.org/source/xref/freebsd-head/sys/dev/rtwn/if_rtwnreg.h#150.
Notice how the second parameter 'reg' is a uint8_t.

The rtwn_pci_write_4's addr is uint16_t, the rtwn_rf_prog's addr is a
uint8_t. How would I reconcile this type mismatch? Additionally, the
Linux version of this block of code has all register values as a
uint32_t. It is not a matter of a cast, because some values definitely
use more than 1 byte (ie 0xFFE).

Suggestions on how to reconcile and resolve this issue?

Thanks!
Farhan Khan