This is in no way a complete DFS/radar detection implementation!
It merely creates an abstracted interface which allows for future
development of the DFS radar detection code.
Note: Net80211 already handles the bulk of the DFS machinery,
all we need to do here is figure out that a radar event has occured
and inform it as such. It then drives the DFS state engine for us.
The "null" DFS radar detection module is included by default;
it doesn't require a device line.
This commit:
* Adds a simple abstracted layer for radar detection state -
sys/dev/ath/ath_dfs/;
* Implements a null DFS module which doesn't do anything;
(ie, implements the exact behaviour at the moment);
* Adds hooks to the ath driver to process received radar events
and gives the DFS module a chance to determine whether
a radar has been detected.
Obtained from: Atheros
