This is a pretty good reference for teaching an almost-11n-capable
driver about 11n.
It enables HT20 operation, A-MPDU/A-MSDU RX, but no aggregate support
for transmit. That'll come later. This means that receive throughput
should be higher, but transmit throughput won't have changed much.
* Disable bgscan - for now, bgscan will interfere with AMPDU TX/RX,
so until we correctly handle it in software driven scans, disable.
* Add null 11n methods for channel width / ampdu_enable.
the firmware can apparently handle ampdu tx (and hopefully block-ack
handling and retransmission) so I'll go review the linux code and
figure it out.
* Set the number of tx/rx streams. I /hope/ that nchains == nstreams
here.
* Add 11n channels in the call to ieee80211_init_channels().
* Don't enable HT40 for now - I'll have to verify the channel set command
and tidy it up a bit first.
* Teach the RX path about M_AMPDU for 11n nodes. Kinda wonder why
we aren't just doing this in net80211 already, this is the fourth
driver I've had to do this to.
* Teach rate2ridx() about MCS rates and what hardware rates to use.
* Teach the urtwn_tx_data() routine about MCS/11ng transmission.
It doesn't know about short-gi and 40MHz modes yet; that'll come
later.
* For 8192CU firmware, teach the rate table code about MCS rates.
* Ensure that the fixed rate transmit sets the right transmit flag
so the firmware obeys the driver transmit path.
* Set the default transmit rate to MCS4 if no rate control is available.
* Add HT protection (RTS-CTS exchange) support.
* Add appropriate XXX TODO entries.
TODO:
* 40MHz, short-gi, etc - channel tuning, TX, RX;
* teach urtwn_tx_raw() about (more) 11n stuff;
* A-MPDU TX would be nice!
Thanks to Andriy (avos@) for reviewing the code and testing it on IRC.
Tested:
* RTL8188EU - STA (me)
* RTL8192CU - STA (me)
* RTL8188EU - hostap (avos)
* RTL8192CU - STA (avos)
Reviewed by: avos
cf9be7c92a