sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

[ath_rate_sample] Limit the tx schedules for A-MPDU ; don't take short retries
into account and remove the requirement that the MCS rate is "higher" if we're
considering a new rate.

Ok, another fun one.

* In order for reliable non-software retried higher MCS rates, the TX schedules
(inconsistently!) use hard-coded lower rates at the end of the schedule.
Now, hard-coded is a problem because (a) it means that aggregate formation
is limited by the SLOWEST rate, so I never formed large AMDU frames for
3 stream rates, and (b) if the AP disables lower rates as base rates, it
complains about "unknown rix" every frame you transmit at that rate.

So, for now just disable the third and fourth schedule entry for AMPDUs.
Now I'm forming 32k and 64k aggregates for the higher density MCS rates
much more reliably.

It would be much nicer if the rate schedule stuff wasn't fixed but instead
I'd just populate ath_rc_series[] when I fetch the rates. This is all a
holdover of ye olde pre-11n stuff and I really just need to nuke it.

But for now, ye hack.

* The check for "is this MCS rate better" based on MCS itself is just garbage.
It meant things like going MCS0->7 would be fine, and say 0->8->16 is fine,
(as they're equivalent encoding but 1,2,3 spatial streams), BUT it meant
going something like MCS7->11 would fail even though it's likely that
MCS11 would just be better, both for EWMA/BER and throughput.

So for now just use the average tx time. The "right" way for this comparison
would be to compare PHY bitrates rather than MCS / rate indexes, but I'm not
yet there. The bit rates ARE available in the PHY index, but honestly
I have a lot of other cleaning up to here before I think about that.

* Don't include the RTS/CTS retry count (and thus time) into the average tx time
caluation. It just makes temporarily failures make the rate look bad by
QUITE A LOT, as RTS/CTS exchanges are (a) long, and (b) mostly irrelevant
to the actual rate being tried. If we keep hitting RTS/CTS failures then
there's something ELSE wrong on the channel, not our selected rate.

[ath] [ath_rate] Extend ath_rate_sample to better handle 11n rates and aggregates.

My initial rate control code was .. suboptimal. I wanted to at least get MCS
rates sent, but it didn't do anywhere near enough to handle low signal level links
or remotely keep accurate statistics.

So, 8 years later, here's what I should've done back then.

* Firstly, I wasn't at all tracking packet sizes other than the two buckets
(250 and 1600 bytes.) So, extend it to include 4096, 8192, 16384, 32768 and
65536. I may go add 2048 at some point if I find it's useful.

This is important for a few reasons. First, when forming A-MPDU or AMSDU
aggregates the frame sizes are larger, and thus the TX time calculation
is woefully, increasingly wrong. Secondly, the behaviour of 802.11 channels
isn't some fixed thing, both due to channel conditions and radios themselves.
Notably, there was some observations done a few years ago on 11n chipsets
which noticed longer aggregates showed an increase in failed A-MPDU sub-frame
reception as you got further along in the transmit time. It could be due to
a variety of things - transmitter linearity, channel conditions changing,
frequency/phase drift, etc - but the observation was to potentially form
shorter aggregates to improve BER.

* .. and then modify the ath TX path to report the length of the aggregate sent,
so as the statistics kept would line up with the correct bucket.

* Then on the rate control look-up side - i was also only using the first frame
length for an A-MPDU rate control lookup which isn't good enough here.
So, add a new method that walks the TID software queue for that node to
find out what the likely length of data available is. It isn't ALL of the
data in the queue because we'll only ever send enough data to fit inside the
block-ack window, so limit how many bytes we return to roughly what ath_tx_form_aggr()
would do.

* .. and cache that in the first ath_buf in the aggregate so it and the eventual
AMPDU length can be returned to the rate control code.

* THEN, modify the rate control code to look at them both when deciding which bucket
to attribute the sent frame on. I'm erring on the side of caution and using the
size bucket that the lookup is based on.

Ok, so now the rate lookups and statistics are "more correct". However, MCS rates
are not the same as 11abg rates in that they're not a monotonically incrementing
set of faster rates and you can't assume that just because a given MCS rate fails,
the next higher one wouldn't work better or be a lower average tx time.

So, I had to do a bunch of surgery to the best rate and sample rate math.
This is the bit that's a WIP.

* First, simplify the statistics updates (update_stats()) to do a single pass on
all rates.
* Next, make sure that each rate average tx time is updated based on /its/ failure/success.
Eg if you sent a frame with { MCS15, MCS12, MCS8 } and MCS8 succeeded, MCS15 and MCS
12 would have their average tx time updated for /their/ part of the transmission,
not the whole transmission.
* Next, EWMA wasn't being fully calculated based on the /failures/ in each of the
rate attempts. So, if MCS15, MCS12 failed above but MCS8 didn't, then ensure
that the statistics noted that /all/ subframes failed at those rates, rather than
the eventual set of transmitted/sent frames. This ensures the EWMA /and/ average
TX time are updated correctly.
* When picking a sample rate and initial rate, probe rates aroud the current MCS
but limit it to MCS0..7 /for all spatial streams/, rather than doing crazy things
like hitting MCS7 and then probing MCS8 - MCS8 is basically MCS0 but two spatial
streams. It's a /lot/ slower than MCS7. Also, the reverse is true - if we're at
MCS8 then don't probe MCS7 as part of it, it's not likely to succeed.
* Fix bugs in pick_best_rate() where I was /immediately/ choosing the highest MCS
rate if there weren't any frames yet transmitted. I was defaulting to 25% EWMA and
.. then each comparison would accept the higher rate. Just skip those; sampling
will fill in the details.

So, this seems to work a lot better. It's not perfect; I'm still seeing a lot of
instability around higher MCS rates because there are bursts of loss/retransmissions
that aren't /too/ bad. But i'll keep iterating over this and tidying up my hacks.

Ok, so why this still something I'm poking at? rather than porting minstrel_ht?

ath_rate_sample tries to minimise airtime, not maximise throughput. I have
extended it with an EWMA based on sub-frame success/failures - high MCS rates
that have partially successful receptions still show super short average frame
times, but a /lot/ of retransmits have to happen for that to work.
So for MCS rates I also track this EWMA and ensure that the rates I'm choosing
don't have super crappy packet failures. I don't mind not getting lower
peak throughput versus minstrel_ht; instead I want to see if I can make "minimise
airtime" work well.

Tested:

* AR9380, STA mode
* AR9344, STA mode
* AR9580, STA/AP mode

[ath] [ath_rate] Add some extra data into the rate control lookup.

Right now (well, since I did this in 2011/2012) the rate control code
makes some super bad choices for 11n aggregates/rates, and it tracks
statistics even more questionably.

It's been long enough and I'm now trying to use it again daily, so let's
start by:

* telling the rate control code if it's an aggregate or not;
* being clearer about the TID - yes it can be extracted from the
ath_buf but this way it can be overridden by the caller without
changing the TID itself.

(This is for doing experiments with voice/video QoS at some point..)

* Return an optional field to limit how long the aggregate is in
microseconds. Right now the rate control code supplies a rate table
and the ath aggr form code will look at the rate table and limit
the aggregate size to 4ms at the slowest rate. Yeah, this is pretty
terrible.

* Add some more TODO comments around handling txpower, rate and
handling filtered frames status so if I continue to have spoons for
this I can go poke at it.

[ath] [ath_rate] Fix ANI calibration during non-ACTIVE states; start poking at rate control

These are some fun issues I've found with my upstairs wifi link at such a ridiculous
low signal level (like, < 5dB.)

* Add per-station tx/rx rssi statistics, in potential preparation to use that
in the RX rate control.

* Call the rate control on each received frame to let it potentially use
it as a hint for what rates to potentially use. It's a no-op right now.

* Do ANI calibration during scan as well. The ath_newstate() call was disabling the
ANI timer and only re-enabling it during transitions to _RUN. This has the
unfortunate side-effect that if ANI deafened the NIC because of interference
and it disassociated, it wouldn't be reset and the scan would never hear beacons.

The ANI configuration is stored at least globally on some HALs and per-channel
on others. Because of this a NIC reset wouldn't help; the ANI parameters would
simply be programmed back in.

Now, I have a feeling I also need to do this during AUTH/ASSOC too and maybe,
if I'm feeling clever, I need to reset the ANI parameters on a given channel
during a transition through INIT or if the VAP is destroyed/re-created.
However for now this gets me out of the immediate weeds with connectivity
upstairs (and thus I /can/ commit); I'll keep chipping away at tidying this
stuff up in subsequent commits.

Tested:

* AR9344 (Wasp), 2G STA mode

sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Update the rate series setup code to use the decisions already made in
ath_tx_rate_fill_rcflags(). Include setting up the TX power cap in the
rate scenario setup code being passed to the HAL.

Other things:

* add a tx power cap field in ath_rc.
* Add a three-stream flag in ath_rc.
* Delete the LDPC flag from ath_rc - it's not a per-rate flag, it's a
global flag for the transmission.

Add missing flags.

Create an ioctl API for fetching the current rate control information.

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

Merge in ath rate flags and ath_rc_series from my 11n TX branch.
This is in preparation for 802.11n TX aggregation support.

Add a new method to the rate control modules which extract out the
three other rates and try counts.

The 11n rate scenario path wants to take a list of rate and tries,
rather than calling setupxtxdesc().

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

now that the new association callback is used when joining a bss we can
eliminate the ath_rate_newassoc callback and associated code

- Import the HEAD csup code which is the basis for the cvsmode work.

Multi-bss (aka vap) support for 802.11 devices.

Note this includes changes to all drivers and moves some device firmware
loading to use firmware(9) and a separate module (e.g. ral). Also there
no longer are separate wlan_scan* modules; this functionality is now
bundled into the wlan module.

Supported by: Hobnob and Marvell
Reviewed by: many
Obtained from: Atheros (some bits)

update copyrights to 2007 and convert to be 2-clause bsd-only

Track v0.9.20.3 hal:

o no more ds_vdata in tx/rx descriptors
o split h/w tx/rx descriptor from s/w status
o as part of the descriptor split change the rate control module api
so the ath_buf is passed in to the module so it can fetch both
descriptor and status information as needed
o add some const poisoning

Also for sample rate control algorithm:

o split debug msgs (node, rate, any)
o uniformly bounds check rate indices (and in some cases correct checks)
o move array index ops to after bounds checking
o use final tsi from the status block instead of the h/w descriptor
o replace h/w descriptor struct's with proper mask+shift defs (this
doesn't belong here; everything is known by the driver and should
just be sent down so there's no h/w-specific knowledge)

MFC after: 1 month

nuke unintentional use of HAL_BOOL type

rev rate control api to pass the both the first+last tx descriptors
to the rate control module for tx complete processing; this enables
rate control algorithms to extract the packet length for xmits that
require multiple descriptors

bump copyright for 2005

Update with last year of work.