On 01/05/15 18:38, Paul Bolle wrote:
On Mon, 2015-01-05 at 11:14 +0100, Arend van Spriel wrote:
On 01/03/15 23:28, Paul Bolle wrote:
Side note: am I correct in thinking that there's some successor to
CFG80211_WEXT and that the ipw2200 driver could, at least in theory, be
ported to that successor? (ipw2200 hardware appears to be a bit old, so
probably no one would care enough to actually do that.)
net/wireless/kconfig doesn't mention anything like that, so probably I'm
just confused.
ipw2200 is a WEXT driver using some wext functionality (and struct
wiphy) provided by cfg80211 hence it needs CFG80211_WEXT. I guess that
is what makes it confusing.
It doesn't help that I hardly know anything about mac80211, cfg80211 and
nl80211 (and lib80211 for that matter). To me these are mostly just
names that end in 80211.
Grapjas ;-)
cfg80211 provides thin-layer API for fullmac drivers (running 802.11
stack on the device) and mac80211-based drivers (running 802.11 stack in
kernel).
Anyhow, concerning, CFG80211_WEXT: it seems the only functionality
provided by that symbol that ipw2200 uses directly is
cfg80211_wext_giwname(). Perhaps ipw2200 could have a private version of
that function, something like ipw2100's ipw2100_wx_get_name(). Should be
trivial to implement (ie, it could take _me_ a day or two).
Indeed or even an hour or two.
But perhaps ipw2200 uses CFG80211_WEXT _indirectly_ too. Ie, in
net/wireless/core.c I stumbled on
#ifdef CONFIG_CFG80211_WEXT
rdev->wiphy.wext =&cfg80211_wext_handler;
#endif
This is the "wext compatibility" being enabled for any cfg80211 or
mac80211 based driver.
But I net/wireless/wext-core.c I then found
#ifdef CONFIG_CFG80211_WEXT
if (dev->ieee80211_ptr&& dev->ieee80211_ptr->wiphy)
handlers = dev->ieee80211_ptr->wiphy->wext;
#endif
wext-core is the WEXT framework and here it extracts WEXT handlers from
a cfg80211/mac80211-based driver that are store in wiphy structure.
#ifdef CONFIG_WIRELESS_EXT
if (dev->wireless_handlers)
handlers = dev->wireless_handlers;
#endif
Here wext-core extracts WEXT handlers from a WEXT driver. struct
net_device::wireless_handlers is only defined for CONFIG_WIRELESS_EXT.
(There's much more to discover about WEXT, of course.) Anyhow, IPW2200
uses both CFG80211_WEXT and WIRELESS_EXT and cfg80211_wext_handler and
ipw2200's wireless_handlers appear to cover the same set of IOCTLS (one
exception: SIOCSIWPMKSA). So by now I'm really puzzled how this all fits
together.
I think ipw2200 is a bit of both worlds indeed adopting the use of
struct wiphy and wiphy_register() call. That seems to suggest it is a
cfg80211 driver, but it does not register any cfg80211 driver callbacks
(see libipw_config_ops in libipw_module.c). So it overrides the WEXT
ioctls because it needs that to interact with the device.
Regards,
Arend
Thanks,
Paul Bolle
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