few changes:
- there was a bug in rl_list_tx_init(): it was calculating the registers
to initialize incorrectly. Not a problem on the x86 where unaligned
access are allowed, but a problem on the alpha.
- set rl_btag accordingly depending on the machine type
- rl_rxeof() needs to be sure to longword-align the packet data. This
is a little tricky since we copy the data out of the receive buffer
using m_devget(), however there's no way to tell m_devget() to fill
in the mbufs starting at a particular offset. To get around this,
we tell m_devget to copy bytes+2 bytes starting at offset offset-2. This
results in the proper alignment, and we can trim off the two leading
bytes afterwards with m_adj(). We also allocate some extra space before
the start of the receive buffer so that we don't get into trouble in
the case where offset == 0.
- redefine vtophys() in if_rlreg.h for the alpha.
Making this chipset work on the alpha is sort of the inverse of putting
a jet engine on a rowboat (putting a propeller on a 747?) but when
you can get these things for $5 a pop, it's hard to stop people from
buying them.