juanmaneo / at76c503a Goto Github PK

This is old linux driver for inventel usb dongle based on at76c503 chip
It was merged in linux kernel at some point so it's there only for educational purposes
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Orginal README notice follows :


at76c503 - linux driver for Atmel at76c503 based usb wlan adapters
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This is another driver for the Atmel based USB WLAN adaptors. I am
developing this driver in private. I am not associated with Atmel or
any corporation that builds devices with this chip. My only
information source is the driver from
http://atmelwlandriver.sourceforge.net.

Look at http://at76c503a.berlios.de/ for more accurate information,
mailing lists and links. This README is probably outdated.


Known devices with this chip are:
- Belkin F5D6050
- Dynalink/Askey WLL013
- Linksys WUSB11 v2.6
- Netgear MA101B
and many more.

Reqirements:
------------

- Kernel 2.4.x. I am developing the driver on 2.4.23, but it
  reportedly also works on 2.4.20, 2.4.19, 2.4.18 and 2.4.16.
- kernel 2.6.x: 2.6.1-4 were reported to work fine. 


Installation:
-------------

make
make install

(with kernel 2.6 you must be run for both steps).


Running:
--------

Plug in the adapter. If you already used it under Windows or with the
driver from atmelwlandriver.sourceforge.net, replug the device
(ie. plug out and in again).

If you have hotplug installed, the drivers should now be loaded. If not,
load them by hand:

modprobe -v at76c503-rfmd
or
insmod usbdfu.o; insmod at76c503.o; insmod at76c503-rfmd.o

You can give the network device another name than wlanX by giving
the module the netdev_name parameter. Eg.
insmod at76c503-rfmd.o netdev_name=eth%d
would give the first device the name eth0, the second eth1 etc...

Check if the modules are loaded with lsmod. It should look like this:

...
at76c503-rfmd          38656   0  (unused)
at76c503               34004   0  [at76c503-rfmd]
usbdfu                  9144   0  [at76c503-rfmd]
...

setup networking (replace <iface> with wlan0, wlan1, ..., <ch> with a
channel number (1..14) <essid> with your network id (a string), <ip>
with an IP address)

iwconfig <iface> channel <ch> mode ad-hoc essid <essid>
ifconfig <iface> <ip>

Example:
iwconfig wlan2 mode ad-hoc channel 10 essid okuwlan
ifconfig wlan2 192.168.0.4

Test it by pinging another host with a wlan adaptor.

Note that the firmware survives reboots of the computer, but not
unplugging the device.

If you get problems:
Look with dmesg, if there are error messages.

Power Save Modes in Infrastructure Mode
---------------------------------------
You can activate 802.11 power save mode by executing
    iwconfig wlanX power on period N
The default period value is 0 and the smallest possible period
of power save (listen interval) is two beacon intervals.
This should lower power consumption, but decrease data throughput and
increase delays.

There is an Atmel specific power save mode called "smart power save"
which switches the device into active state (by a NULL packet to the AP)
as soon as there are pending packets at the AP for the STA and put it
back into doze state after the next beacon. This saves the need for
sending PS_POLL packets.
It can only be activated by
   iwpriv wlanX powersave_mode 3
I don't know if the listen_interval is used in this mode, too.
If yes, you can only set it earlier by iwconfig, e.g.
   iwconfig wlanX power on period N
   iwpriv wlanX powersave_mode 3


Private Parameters
------------------

In addition to the parameters of iwconfig, some can be set by iwpriv:
- long preamble:  iwpriv wlanX short_preamble 0
- short preamble: iwpriv wlanX short_preamble 1
- amount of debug messages:   iwpriv wlanX set_debug N
  with N a combination of bits, see DBG_* in at76c503.c
- power save mode: iwpriv wlanX powersave_mode N (* N = 1,2,3 
  for none, save, smart save *)
- scan channel time: iwpriv wlanX scan_times <min_ch_time> <max_ch_time>
  (this may be required for 0.90.x firmware, i.e. Intersil radios)

Be aware that shared key authentication requires a WEP key.

at76c503.o module parameters
----------------------------
The above private parameters can be set by module parameters (inside
/etc/modules.conf or on the "modprobe" command line) as well (see
at76c503a.c for a short explanation and the default values):

debug
scan_min_time
scan_max_time
scan_mode
preamble_type
auth_mode
pm_mode
pm_period

Known Problems
--------------

1) Bugs of the firmware 0.90.0-44 (the latest available for device with
  Intersil radio after Atmel stopped support for Intersil radio
  chipsets):
  - active scan doesn't send ProbeReq neither in adhoc or in
    infrastructure (managed) mode

    * If your ad-hoc peer sends the beacon in longer intervals,
      the Atmel driver may not find it. Try to increase the max
      channel time to 500 or 1000 (default 120) by calling
              iwpriv wlanX scan_times 10 <max channel time>
      If you found a working value, add the module parameter
      scan_max_time to /etc/modules.conf .

    * You cannot connect to an access point which hides its SSID and
      requires the STA to probe it!

  - After joining an existing IBSS of a 2MBit card, the basic rates are
    wrong in the beacon, e.g.
    a 2 MBit card broadcasts a basic rate set of 1 + 2 MBit/s,
    but the Atmel device sends out basic rates of 1,2,5.5 and 11 MBit/s
    Subsequently it cannot connect to the 2 MBit card, because it sends
    it's data packets to broadcast addresses with 11 MBit/s.

  - power saving modes does not work

2) firmware 1.101.0-84
  - if a 2MBit card joins an IBSS (ad-hoc mode) initiated by the Atmel
    device (which currently broadcasts 1+2 MBit/s as the basic rates
    and 5.5 and 11 MBit/s as (additional) operational rates), the
    Atmel device sends out broadcast packets (e.g. ARP requests) with
    11 MBit/s. This may be fixed by changing the tx rate in iwconfig
    from "auto" (default) to 1M or 2M.
    I'm not sure if this is a firmware bug or a problem in the driver.
    


Thanks to (in no particular order):
- the authors (Stavros et.al.) of the usbvnet driver (atmelwlandriver.sourceforge.net)
- Joerg Albert for lots of patches
- Brad Hards and Bas Vermeulen for the firmware code, which I ported to kernel space
- David Gibson, I used his orinoco driver for learning
- the author(s) of the usbnet driver
- the author(s) of the rtl8150 driver
- lots of other authors of usb and wlan drivers, where I stole code from
- Pavel Roskin for testing, debugging and his patches
- Nick Jones for rewriting the iw_handler interface

Oliver Kurth, Mon,  6 Jan 2003 22:39:47 +0100
updated by Joerg Albert, Thu, 1 May 2003 and later