There's still a lot of random issues to sort out with the radio side of
things and AMPDU RX handling (and completely missing AMPDU TX handling!)
but if people wish to give this a go and assist in debugging the
issues, they can define ATH_DO_11N to enable it.
I'm just re-iterating - this is here to allow people to assist in
further 11n development; it is not any indication that the 11n support
is complete and functional.
Important notes:
* This doesn't support 1-stream cards yet - (eg AR9285) - the various bits
that negotiate TX/RX MCS don't know not to try >1 stream TX or negotiate
1-stream RX; so don't enable 11n unless you've first taught the rate
control module and the net80211 stack to negotiate 1-stream stuff;
* The only rate control module minimally 11n aware is ath_rate_sample;
* ath_rate_sample doesn't know about HT/40; so airtime will be incorrectly
calculated;
* The AR9160 and AR9280 radio code is unreliable at the higher MCS rates for
some reason; this will definitely impact 11n performance;
* AMPDU-TX isn't yet implemented;
* AMPDU-RX may be a bit buggy still and will definitely suffer from the
radio unreliability mentioned above (ie, don't expect 150/300mbit
RX just yet.)
The correct bit to set is 0x1 in the high MAC address byte, not 0x80.
The hardware isn't programmed with that bit (which is the multicast
adress bit.)
The linux ath9k keycache code uses that bit in the MAC as a "this is
a multicast key!" and doesn't set the AR_KEYTABLE_VALID bit.
This tells the hardware the MAC isn't to be used for unicast destination
matching but it can be used for multicast bssid traffic.
This fixes some encryption problems in station mode.
PR: kern/154598
Revert back to the previous method of doing it for where a node can be
identified and it's an 11n node.
I'll have to do some further research into exactly what is being messed up
with the sequence number matching and I'll then revisit this.
This doesn't yet take into account HT40 packet durations as the node info
(needed to know if it's a HT20 or HT40 node) isn't available everywhere
it needs to be.
putting descriptors (not buffers) across a 4k page boundary can cause issues.
I've not seen it in production myself but it apparently can cause problems.
So, in preparation for addressing this workaround, (re)-expose the particular
HAL capability bit which marks whether the chipset has support for cross-4k-
boundary transactions or not.
A subsequent commit will modify the descriptor allocation to avoid allocating
descriptor entries that straddle a 4k page boundary.
* The existing radio config code was for the AR5416/AR9160 and missed out
on some of the AR9280 specific stuff. Include said stuff from ath9k.
* Refactor out the gain control settings into a new function, again pilfered
from ath9k.
* Use the analog register RMW macro when touching analog registers.
Obtained from: Linux ath9k
This fixes two problems -
* All packets need to be processed here, not just aggregate ones - as any
received frames (AMPDU or otherwise) in the given TID (traffic class id)
will update the sequence number and, implied with that, update the window;
* It seems there's situations where packets aren't matching a current node but
somehow need to be tracked. Thus just tag them all for now; I'll figure out
the why later.
Whilst I'm here, bump the stats counters whilst I'm at it.
This fixes AMPDU RX in my tests; the main problems now stem from what look
like PHY level error/retransmits which are impeding general throughput, incl.
AMPDU.
TX chainmask.
since the upper layers don't (yet) know about the active TX/RX chainmasks,
it can't tell the rate scenario functions what to use. I'll eventually sort
this out; this restores functionality in the meantime.
This isn't strictly required to TX (at least non-agg and non-HT40,
non-short-GI) frames; but as it needs to be done anyway, just get
it done.
Linux ath9k uses the rate scenario style path for -all- packets,
legacy or otherwise. This code does much the same.
Beacon TX still uses the legacy, non-rate-scenario TX descriptor
setup. Ath9k also does this.
This 11n rate scenario path is only called for chips in the AR5416
HAL; legacy chips use the previous interface for TX'ing.
A-MPDU RX interferes with packet retransmission/reordering.
In local testing, I was seeing A-MPDU being negotiated and then
not used by the AP sending frames to the STA; the STA would then
treat non A-MPDU frames that are retransmits as out of the window
and get plain confused.
The hardware RX status descriptor has a "I'm part of an aggregate"
bit; so this should eventually be tested and then punted to the
A-MPDU reorder handling only if it has this bit set.
The AR5416 and later TX descriptors have new fields for supporting
11n bits (eg 20/40mhz mode, short/long GI) and enabling/disabling
RTS/CTS protection per rate.
These functions will be responsible for initialising the TX descriptors
for the AR5416 and later chips for both HT and legacy frames.
Beacon frames will remain using the non-11n TX descriptor setup for now;
Linux ath9k does much the same.
Note that these functions aren't yet used anywhere; a few more framework
changes are needed before all of the right rate information is available
for TX.
function; which will be later used by the TX path to determine
whether to use the extended features or not.
* Break out the descriptor chaining logic into a separate function;
again so it can be switched out later on for the 11n version when
needed.
* Refactor out the encryption-swizzling code that's common in the
raw and normal TX path.
The higher levels (net80211, if_ath, ath_rate) need this to make correct
choices about what MCS capabilities to advertise and what MCS rates are
able to be TXed.
In summary:
* AR5416 - 2/3 antennas, 2x2 streams
* AR9160 - 2/3 antennas, 2x2 streams
* AR9220 - 2 antennas, 2x2 sstraems
* AR9280 - 2 antennas, 2x2 streams
* AR9285 - 2 antennas but with antenna diversity, 1x1 stream
After inspecting the ath9k source, it seems the AR5416 and later MACs
don't take an explicit RTS/CTS duration. A per-scenario (ie, what multi-
rate retry became) rts/cts control flag and packet duration is provided;
the hardware then apparently fills in whatever details are required.
The per-rate sp/lpack duration calculation just isn't used anywhere
in the ath9k TX packet length calculations.
The burst duration register controls something different; it seems to
be involved with RTS/CTS protection of 11n aggregate frames and is set
via a call to ar5416Set11nBurstDuration().
I've done some light testing with rts/cts protected frames and nothing
seems to break; but this may break said RTS/CTS and CTS-to-self protection.
Each different radio chipset has a different "good" range of CCA
(clear channel access) parameters where, if you write something
out of range, it's possible the radio will go deaf.
Also, since apparently occasionally reading the NF calibration
returns "wrong" values, so enforce those limits on what is being
written into the CCA register.
Write a default value if there's no history available.
This isn't the case right now but it may be later on when "off-channel"
scanning occurs without init'ing or changing the NF history buffer.
(As each channel may have a different noise floor; so scanning or
other off-channel activity shouldn't affect the NF history of
the current channel.)
* I messed up a couple of things in if_athvar.h; so fix that.
* Undo some guesswork done in ar5416Set11nRateScenario() and introduce a
flags parameter which lets the caller set a few things. To begin with,
this includes whether to do RTS or CTS protection.
* If both RTS and CTS is set, only do RTS. Both RTS and CTS shouldn't be
set on a frame.
There's two reasons for this:
* the raw and non-raw TX path shares a lot of duplicate code which should be
refactored;
* the 11n-ready chip TX path needs a little reworking.
This is just the bare minimum needed to teach ath_rate_sample to try
and handle MCS rates. It doesn't at all attempt to find the best
rate by any means - it doesn't know anything about the MCS rate
relations, TX aggregation or any of the much sexier 11n stuff
that's out there.
It's just enough to transmit 11n frames and handle TX completion.
It shouldn't affect legacy (11abg) behaviour.
Obtained from: rpaulo@
This will eventually be used by rate control modules and by the TX
code for calculating packet duration when handling rts/cts protection.
Obtained from: sam@, rpaulo@, linux ath9k
The defaults enabled three chains on the AR5416 even if the card has two
chains. This restores that and ensures that only the correct TX/RX
chainmasks are used.
When HT modes are enabled, all TX chains will be correctly enabled.
This should now enable analog chain swapping with 2-chain cards.
I'm not sure if this is needed for just the AR5416 or whether
it also applies to AR9160, AR9280 and AR9287 (later on); I'll have
to get clarification.
This, along with an initval change which will appear in a subsequent commit,
fixes bus panics that I have been seing with the AR9220 on a Routerstation Pro
(AR7161 MIPS board.)
Obtained from: Linux ath9k
PR: kern/154220
ath9k does a few different things here during config - if it's an early
AR5416 with two chains, it enables all three chains for calibration and
then restores the chainmask to the original values after initial
calibration has completed.
The reason behind this commit is to begin breaking out the chainmask
configuration for this specific reason; follow-up commits will add
the chainmask restore in the ar5416Reset() routine.
* Re-do the structure size/component math to make sure the struct matches
the expected size
* Just to be clear that we care about bitmask ordering, revert my previous
change and instead define that macro if we're on big-endian.
