rtwn: change the USB TX transfers to only do one pending transfer per endpoint

I found I was getting constant device timeouts when doing anything
more complicated than a single SSH on laptop with RT

rtwn: change the USB TX transfers to only do one pending transfer per endpoint

I found I was getting constant device timeouts when doing anything
more complicated than a single SSH on laptop with RTL8811AU.

After digging into it, i found a variety of fun situations, including
traffic stalls that would recover w/ a shorter (1 second) USB transfer
timeout. However, the big one is a straight up hang of any TX endpoint
until the NIC was reset. The RX side kept going just fine; only the
TX endpoints would hang.

Reproducing it was easy - just start up a couple of traffic streams
on different WME AC's - eg a best effort + bulk transfer, like
browsing the web and doing an ssh clone - throw in a ping -i 0.1
to your gateway, and it would very quickly hit device timeouts every
couple of seconds.

I put everything into a single TX EP and the hangs went away.
Well, mostly.

So after some MORE digging, I found that this driver isn't checking
if the transfers are going into the correct EPs for the packet
WME access category / 802.11 TID; and would frequently be able
to schedule multiple transfers into the same endpoint.

Then there's a second problem - there's an array of endpoints
used for setting up the USB device, with .endpoint = UE_ADDR_ANY,
however they're also being setup with the same endpoint configured
in multiple transfer configs. Eg, a NIC with 3 or 4 bulk TX endpoints
will configure the BK and BE endpoints with the same physical endpoint
ID. This also leads to timed out transfers.

My /guess/ was that the firmware isn't happy with one or both of the
above, and so I solved both.

* drop the USB transfer timeout to 1 second, not 5 seconds -
that way we'll either get a 1 second traffic pause and USB transfer
failure, or a 5 second device timeout. Having both the TX timeout
and the USB transfer timeout made recovery from a USB transfer
timeout (without a NIC reset) almost impossible.

* enforce one transfer per endpoint;
* separate pending/active buffer tracking per endpoint;
* each endpoint now has its own TX callback to make sure the queue /
end point ID is known;
* and only frames from a given endpoint pending queue is going
into the active queue and into that endpoint.
* Finally, create a local wme2qid array and populate it with the
endpoint mapping that ensures unique physical endpoint use.

Locally tested:

* rtl8812AU, 11n STA mode
* rtl8192EU, 11n STA mode (with diffs to fix the channel config / power
timeouts.)

Differential Revision: https://reviews.freebsd.org/D47522

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

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

Merge ^/head r307383 through r307735.

rtwn(4), urtwn(4): merge common code, add support for 11ac devices.

All devices:
- add support for rate adaptation via ieee80211_amrr(9);
- use short preamble for transmitted frames when needed;
- m

rtwn(4), urtwn(4): merge common code, add support for 11ac devices.

All devices:
- add support for rate adaptation via ieee80211_amrr(9);
- use short preamble for transmitted frames when needed;
- multi-bss support:
* for RTL8821AU: 2 VAPs at the same time;
* other: 1 any VAP + 1 sta VAP.
RTL8188CE:
- fix IQ calibration bug (reason of significant speed degradation);
- add h/w crypto acceleration support.
USB:
- A-MPDU Tx support;
- short GI support;
Other:
- add support for RTL8812AU / RTL8821AU chipsets
(a/b/g/n only; no ac yet);
- split merged code into subparts:
* bus glue (usb/*, pci/*, rtl*/usb/*, rtl*/pci/*)
* common (if_rtwn*)
* chip-specific (rtl*/*)
- various other bugfixes.

Due to code reorganization, module names / requirements were changed too:
urtwn urtwnfw -> rtwn rtwn_usb rtwnfw
rtwn rtwnfw -> rtwn rtwn_pci rtwnfw

Tested with RTL8188CE, RTL8188CUS, RTL8188EU and RTL8821AU.

Tested by: kevlo, garga,
Peter Garshtja <peter.garshtja@ambient-md.com>,
Kevin McAleavey <kevin.mcaleavey@knosproject.com>,
Ilias-Dimitrios Vrachnis <id@vrachnis.com>,
<otacilio.neto@bsd.com.br>
Relnotes: yes

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