and from nell(4):
   
   DESCRIPTION
        The nell is a pcmcia bridge for the sbus. It is also known as STP4020,
        the name of the chipset used to implement it, and has SUN part number
        501-2367.


you forgot to meantion the WI_AT_BIGENDIAN_BUS_HACK that is required :-)

you need "options WI_AT_BIGENDIAN_BUS_HACK" in your kernel otherwise the
wavelan driver does not work properly.  i am also using wavelan on a sparc
(infact, this message is composed over that link) quite happily on a classic
running 1.5ZC.


nell0 at sbus0 slot 1 offset 0x0 level 4 (ipl 7) level 7 (ipl 13): rev 1
pcmcia0 at nell0 socket 0
pcmcia1 at nell0 socket 1
wi0 at pcmcia1 function 0: TOSHIBA, Wireless LAN Card, Version 01.01
wi0: 802.11 address 00:02:2d:52:d7:01
wi0: using Lucent Technologies, WaveLAN/IEEE
wi0: Lucent Firmware: Station (6.10.1)


.mrg.