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While playing with the firmware a while back, I discovered a way to
access the device's entire address space before the firmware has been
loaded.
Previously we were loading the firmware early on (during probe) so that
we could read the MAC address from the EEPROM and register a netdevice.
Now that we can read the EEPROM without having firmware, we can defer
firmware loading until later while still reading the MAC address early
on.
This has the advantage that zd1211rw can now be built into the kernel --
previously if this was the case, zd1211rw would be loaded before the
filesystem is available and firmware loading would fail.
Firmware load and other device initialization operations now happen the
first time the interface is brought up.
Some architectural changes were needed: handling of the is_zd1211b flag
was moved into the zd_usb structure, MAC address handling was obviously
changed, and a preinit_hw stage was added (the order is now: init,
preinit_hw, init_hw).
Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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There are 60+ USB wifi adapters available on the market based on the ZyDAS
ZD1211 chip.
Unlike the predecessor (ZD1201), ZD1211 does not have a hardware MAC, so most
data operations are coordinated by the device driver. The ZD1211 chip sits
alongside an RF transceiver which is also controlled by the driver. Our driver
currently supports 2 RF types, we know of one other available in a few marketed
products which we will be supporting soon.
Our driver also supports the newer revision of ZD1211, called ZD1211B. The
initialization and RF operations are slightly different for the new revision,
but the main difference is 802.11e support. Our driver does not support the
QoS features yet, but we think we know how to use them.
This driver is based on ZyDAS's own GPL driver available from www.zydas.com.tw.
ZyDAS engineers have been responsive and supportive of our efforts, so thumbs
up to them. Additionally, the firmware is redistributable and they have
provided device specs.
This driver has been written primarily by Ulrich Kunitz and myself. Graham
Gower, Greg KH, Remco and Bryan Rittmeyer have also contributed. The
developers of ieee80211 and softmac have made our lives so much easier- thanks!
We maintain a small info-page: http://zd1211.ath.cx/wiki/DriverRewrite
If there is enough time for review, we would like to aim for inclusion in
2.6.18. The driver works nicely as a STA, and can connect to both open and
encrypted networks (we are using software-based encryption for now). We will
work towards supporting more advanced features in the future (ad-hoc, master
mode, 802.11a, ...).
Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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