Hi Dan,

The PLX9052-based cards (WL11000 and several others) are a different beast
than the usual PCMCIA-based PRISM2 configuration expected by wlan-ng. I've
just finished writing Windows NDIS drivers to target a PRISM1 card via a
WL11000 for a wireless Internet station adapter product, but that might
not be too helpful in this case. But if someone gets bored and wants to
add PLX9052 support to wlan-ng, here's the general details on how the
WL11000 PCI adapter works:

 - Two PCI I/O address spaces, one 0x80 long which contains the PLX9052
   registers, and one that's 0x40 long mapped to the PCMCIA slot I/O
   address space.

 - One PCI memory address space, mapped to the PCMCIA memory space
   (containing the CIS).

After identifying the I/O and memory space, you can read through the
memory space to confirm the CIS's device ID or manufacturer ID to make
sure it's the expected card. Keep in mind that the PCMCIA spec specifies
the CIS as the lower 8 bits of each word read from the CIS, so to read the
bytes of the CIS, read every other byte (0,2,4,...). Passing that test,
you need to enable the I/O address space on the PCMCIA card via the PCMCIA
COR register. This is the first byte following the CIS. In my case
(which may not have any relation to what's on the PRISM2 cards), COR was
at offset 0x800 within the PCI memory space. Write 0x41 to the COR
register to enable I/O mode and to select level triggered interrupts. To
confirm you actually succeeded, read the COR register back and make sure
it actually got set to 0x41, incase you have an unexpected card inserted.

Following that, you can treat the second PCI I/O address space (the one
that's not 0x80 in length) as the PCMCIA I/O space.

Note that in the Eumitcom's source for their drivers, they register the
interrupt as edge triggered when registering it with the Windows kernel. I
don't recall how to register edge triggered on Linux (if it can be done at
all). But in some experimentation, I don't see much operational
difference between using either interrupt mode. Don't mess with the
interrupt mode in the COR register though, as the PLX9052 wants level
triggers with the way the serial EEPROM configures it on the WL11000.

There's some other little quirks related to timing that I bumped into, but
I don't recall right now. Also, there's two variants of the WL11000 I've
seen, revision A1 and T2. These seem to differ slightly in the timings
configured in the wait-state generator in the PLX9052. There have also
been some comments from Eumitcom that cards shouldn't be hot swapped,
apparently due to risk of cooking the PLX9052. I'm unsure why they
believe this, as I can't see anything in the design that would really
cause a problem, except for crashing drivers not written to expect it. And
having developed drivers for the WL11000, I'd say it's quite tricky to
write code that will successfully deal with a hot unplug. Very odd things
happen on the I/O side of things. But anyway, be warned. Despite that,
I've hot-swapped a number of times during debugging and driver development
for various reasons (stuck WAIT# line after the radio card's firmware
locks up).

Hope this is enough info for someone to add PLX9052 support to the wlan-ng
card. In the case of the WL11000, the PCI ID's are 0x1639/0x0200, with
matching subsystem ID's. Other PLX9052-based manufacturers other than
Eumitcom (or on cards other than the WL11000) may have different PCI ID's.

If anyone needs any more specific info, let me know. I haven't had time
to implement support myself yet, and with the way things are going, might
not have time for a while..

-Ryan

On Mon, 22 Jan 2001, Dan Aronson wrote:

> I recently purchased the PCI wave2net card from Ambicom (which actually
> seems to be a repackaged WL11000 PCI card from Eumitcom.
> Does anyone know how to drive this thing? Thanks in advance.
>
> --dan
> --------------------------------------------------
> Linux WLAN Developer's List
> For more information about this list see:
> http://www.absoval.com/linux-wlan/lists.html
>

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