freebsd-skq/sys/dev/ath/if_ath_tx.h
Adrian Chadd eb6f0de09d Introduce TX aggregation and software TX queue management
for Atheros AR5416 and later wireless devices.

This is a very large commit - the complete history can be
found in the user/adrian/if_ath_tx branch.

Legacy (ie, pre-AR5416) devices also use the per-software
TXQ support and (in theory) can support non-aggregation
ADDBA sessions. However, the net80211 stack doesn't currently
support this.

In summary:

TX path:

* queued frames normally go onto a per-TID, per-node queue
* some special frames (eg ADDBA control frames) are thrown
  directly onto the relevant hardware queue so they can
  go out before any software queued frames are queued.
* Add methods to create, suspend, resume and tear down an
  aggregation session.
* Add in software retransmission of both normal and aggregate
  frames.
* Add in completion handling of aggregate frames, including
  parsing the block ack bitmap provided by the hardware.
* Write an aggregation function which can assemble frames into
  an aggregate based on the selected rate control and channel
  configuration.
* The per-TID queues are locked based on their target hardware
  TX queue. This matches what ath9k/atheros does, and thus
  simplified porting over some of the aggregation logic.
* When doing TX aggregation, stick the sequence number allocation
  in the TX path rather than net80211 TX path, and protect it
  by the TXQ lock.

Rate control:

* Delay rate control selection until the frame is about to
  be queued to the hardware, so retried frames can have their
  rate control choices changed. Frames with a static rate
  control selection have that applied before each TX, just
  to simplify the TX path (ie, not have "static" and "dynamic"
  rate control special cased.)
* Teach ath_rate_sample about aggregates - both completion and
  errors.
* Add an EWMA for tracking what the current "good" MCS rate is
  based on failure rates.

Misc:

* Introduce a bunch of dirty hacks and workarounds so TID mapping
  and net80211 frame inspection can be kept out of the net80211
  layer. Because of the way this code works (and it's from Atheros
  and Linux ath9k), there is a consistent, 1:1 mapping between
  TID and AC. So we need to ensure that frames going to a specific
  TID will _always_ end up on the right AC, and vice versa, or the
  completion/locking will simply get very confused. I plan on
  addressing this mess in the future.

Known issues:

* There is no BAR frame transmission just yet. A whole lot of
  tidying up needs to occur before BAR frame TX can occur in the
  "correct" place - ie, once the TID TX queue has been drained.

* Interface reset/purge/etc results in frames in the TX and RX
  queues being removed. This creates holes in the sequence numbers
  being assigned and the TX/RX AMPDU code (on either side) just
  hangs.

* There's no filtered frame support at the present moment, so
  stations going into power saving mode will simply have a number
  of frames dropped - likely resulting in a traffic "hang".

* Raw frame TX is going to just not function with 11n aggregation.
  Likely this needs to be modified to always override the sequence
  number if the frame is going into an aggregation session.
  However, general raw frame injection currently doesn't work in
  general in net80211, so let's just ignore this for now until
  this is sorted out.

* HT protection is just not implemented and won't be until the above
  is sorted out. In addition, the AR5416 has issues RTS protecting
  large aggregates (anything >8k), so the work around needs to be
  ported and tested. Thus, this will be put on hold until the above
  work is complete.

* The rate control module 'sample' is the only currently supported
  module; onoe/amrr haven't been tested and have likely bit rotted
  a little. I'll follow up with some commits to make them work again
  for non-11n rates, but they won't be updated to handle 11n and
  aggregation. If someone wishes to do so then they're welcome to
  send along patches.

* .. and "sample" doesn't really do a good job of 11n TX. Specifically,
  the metrics used (packet TX time and failure/success rates) isn't as
  useful for 11n. It's likely that it should be extended to take into
  account the aggregate throughput possible and then choose a rate
  which maximises that. Ie, it may be acceptable for a higher MCS rate
  with a higher failure to be used if it gives a more acceptable
  throughput/latency then a lower MCS rate @ a lower error rate.
  Again, patches will be gratefully accepted.

Because of this, ATH_ENABLE_11N is still not enabled by default.

Sponsored by:	Hobnob, Inc.
Obtained from:	Linux, Atheros
2011-11-08 22:43:13 +00:00

128 lines
4.9 KiB
C

/*-
* Copyright (c) 2002-2009 Sam Leffler, Errno Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
* redistribution must be conditioned upon including a substantially
* similar Disclaimer requirement for further binary redistribution.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
* IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGES.
*
* $FreeBSD$
*/
#ifndef __IF_ATH_TX_H__
#define __IF_ATH_TX_H__
/*
* some general macros
*/
#define INCR(_l, _sz) (_l) ++; (_l) &= ((_sz) - 1)
/*
* return block-ack bitmap index given sequence and starting sequence
*/
#define ATH_BA_INDEX(_st, _seq) (((_seq) - (_st)) & (IEEE80211_SEQ_RANGE - 1))
#define WME_BA_BMP_SIZE 64
#define WME_MAX_BA WME_BA_BMP_SIZE
/*
* How 'busy' to try and keep the hardware txq
*/
#define ATH_AGGR_MIN_QDEPTH 2
/*
* Watermark for scheduling TIDs in order to maximise aggregation.
*
* If hwq_depth is greater than this, don't schedule the TID
* for packet scheduling - the hardware is already busy servicing
* this TID.
*
* If hwq_depth is less than this, schedule the TID for packet
* scheduling in the completion handler.
*/
#define ATH_AGGR_SCHED_HIGH 4
#define ATH_AGGR_SCHED_LOW 2
/*
* return whether a bit at index _n in bitmap _bm is set
* _sz is the size of the bitmap
*/
#define ATH_BA_ISSET(_bm, _n) (((_n) < (WME_BA_BMP_SIZE)) && \
((_bm)[(_n) >> 5] & (1 << ((_n) & 31))))
/* extracting the seqno from buffer seqno */
#define SEQNO(_a) ((_a) >> IEEE80211_SEQ_SEQ_SHIFT)
/*
* Whether the current sequence number is within the
* BAW.
*/
#define BAW_WITHIN(_start, _bawsz, _seqno) \
((((_seqno) - (_start)) & 4095) < (_bawsz))
extern void ath_txq_restart_dma(struct ath_softc *sc, struct ath_txq *txq);
extern void ath_freetx(struct mbuf *m);
extern void ath_tx_node_flush(struct ath_softc *sc, struct ath_node *an);
extern void ath_tx_txq_drain(struct ath_softc *sc, struct ath_txq *txq);
extern void ath_txfrag_cleanup(struct ath_softc *sc, ath_bufhead *frags,
struct ieee80211_node *ni);
extern int ath_txfrag_setup(struct ath_softc *sc, ath_bufhead *frags,
struct mbuf *m0, struct ieee80211_node *ni);
extern int ath_tx_start(struct ath_softc *sc, struct ieee80211_node *ni,
struct ath_buf *bf, struct mbuf *m0);
extern int ath_raw_xmit(struct ieee80211_node *ni, struct mbuf *m,
const struct ieee80211_bpf_params *params);
/* software queue stuff */
extern void ath_tx_swq(struct ath_softc *sc, struct ieee80211_node *ni,
struct ath_txq *txq, struct ath_buf *bf);
extern void ath_tx_tid_init(struct ath_softc *sc, struct ath_node *an);
extern void ath_tx_tid_hw_queue_aggr(struct ath_softc *sc, struct ath_node *an,
struct ath_tid *tid);
extern void ath_tx_tid_hw_queue_norm(struct ath_softc *sc, struct ath_node *an,
struct ath_tid *tid);
extern void ath_txq_sched(struct ath_softc *sc, struct ath_txq *txq);
extern void ath_tx_normal_comp(struct ath_softc *sc, struct ath_buf *bf,
int fail);
extern void ath_tx_aggr_comp(struct ath_softc *sc, struct ath_buf *bf,
int fail);
extern void ath_tx_addto_baw(struct ath_softc *sc, struct ath_node *an,
struct ath_tid *tid, struct ath_buf *bf);
extern struct ieee80211_tx_ampdu * ath_tx_get_tx_tid(struct ath_node *an,
int tid);
/* TX addba handling */
extern int ath_addba_request(struct ieee80211_node *ni,
struct ieee80211_tx_ampdu *tap, int dialogtoken,
int baparamset, int batimeout);
extern int ath_addba_response(struct ieee80211_node *ni,
struct ieee80211_tx_ampdu *tap, int dialogtoken,
int code, int batimeout);
extern void ath_addba_stop(struct ieee80211_node *ni,
struct ieee80211_tx_ampdu *tap);
extern void ath_bar_response(struct ieee80211_node *ni,
struct ieee80211_tx_ampdu *tap, int status);
extern void ath_addba_response_timeout(struct ieee80211_node *ni,
struct ieee80211_tx_ampdu *tap);
#endif