Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Implement the quarter rate fractional channel programming for the
AR5416 and AR9280, but leave it disabled by default.

TL;DR: don't enable this code at all unless you go through the process
of getting the NIC re-certified. This is purely to be used as a
reference and NOT a certified solution by any stretch of the imagination.

The background:

The AR5112 RF synth right up to the AR5133 RF synth (used on the AR5416,
derivative is used for the AR9130/AR9160) only implement down to 2.5MHz
channel spacing in 5GHz. Ie, the RF synth is programmed in steps of 2.5MHz
(or 5, 10, 20MHz.) So they can't represent the quarter rate channels
in the 4.9GHz PSB (which end in xxx2MHz and xxx7MHz). They support
fractional spacing in 2GHz (1MHz spacing) (or things wouldn't work,
right?)

So instead of doing this, the RF synth programming for the AR5112 and
later code will round to the nearest available frequency.

If all NICs were RF5112 or later, they'll inter-operate fine - they all
program the same. (And for reference, only the latest revision of the
RF5111 NICs do it, but the driver doesn't yet implement the programming.)

However:

* The AR5416 programming didn't at all implement the fractional synth
work around as above;
* The AR9280 programming actually programmed the accurate centre frequency
and thus wouldn't inter-operate with the legacy NICs.

So this patch:

* Implements the 4.9GHz PSB fractional synth workaround, exactly as the
RF5112 and later code does;
* Adds a very dirty workaround from me to calculate the same channel
centre "fudge" to the AR9280 code when operating on fractional frequencies
in 5GHz.

HOWEVER however:

It is disabled by default. Since the HAL didn't implement this feature,
it's highly unlikely that the AR5416 and AR928x has been tested in these
centre frequencies. There's a lot of regulatory compliance testing required
before a NIC can have this enabled - checking for centre frequency,
for drift, for synth spurs, for distortion and spectral mask compliance.
There's likely a lot of other things that need testing so please don't
treat this as an exhaustive, authoritative list. There's a perfectly good
process out there to get a NIC certified by your regulatory domain, please
go and engage someone to do that for you and pay the relevant fees.

If a company wishes to grab this work and certify existing 802.11n NICs
for work in these bands then please be my guest. The AR9280 works fine
on the correct fractional synth channels (49x2 and 49x7Mhz) so you don't
need to get certification for that. But the 500KHz offset hack may have
the above issues (spur, distortion, accuracy, etc) so you will need to
get the NIC recertified.

Please note that it's also CARD dependent. Just because the RF synth
will behave correctly doesn't at all mean that the card design will also
behave correctly. So no, I won't enable this by default if someone
verifies a specific AR5416/AR9280 NIC works. Please don't ask.

Tested:

I used the following NICs to do basic interoperability testing at
half and quarter rates. However, I only did very minimal spectrum
analyser testing (mostly "am I about to blow things up" testing;
not "certification ready" testing):

* AR5212 + AR5112 synth
* AR5413 + AR5413 synth
* AR5416 + AR5113 synth
* AR9280

Enable fractional 5G mode on half/quarter rate channels.

Obtained from: Linux ath9k

Add the 11n chipset RF frontends to the linker set, even though they're not
attached this way.

The AR5212 based NICs have a variety of RF frontends, so there's a linker set
which the AR5212 attach routine calls. The same framework is used for the
AR5416 and later but as there's a fixed RF frontend for each 11n NIC, it
is just directly attached.

However in the case of compiling a cut down HAL (eg _just_ AR9130 WMAC support),
the linker set ends up being empty and this causes the compile to fail.

So this is just a workaround for that - it means those users who wish an 11n
only HAL can compile the 11n chipsets and RF frontend they need, and just
"ath_ar5212" for the AR5212/AR5416 common code, and it'll just work.

Sponsored by: Hobnob, Inc.

Introduce the FRAC_5G EEPROM parameter.

This seems to indicate whether to program the NIC for fractional 5ghz
mode (ie, 5mhz spaced channels, rather than 10 or 20mhz spacing) or not.
The default (0) seems to mean "only program fractional mode if needed".
A different value (eg 1) seems to always enable fractional 5ghz mode
regardless of the frequency.

Obtained from: Atheros
Approved by: re (kib)

Fix the nfarray offsets for the ar2133/ar5133 radio - (AR5416, AR9160, etc.)

The offsets didn't match the assumption that nfarray[] is ordered by the
chainmask bits and programmed via the register order in ar5416_cca_regs[].
This repairs that damage and ensures that chain 1 is programmed correctly.
(And extension channels will now be programmed correctly also.)

This fixes some of the stuck beacons I've been seeing on my AR9160/AR5416
setups - because Chain 1 would be programmed -80 or -85 dBm, which is
higher than the actual noise floor and thus convincing the radio that
indeed it can't ever transmit.

Use analog delay macro for modifying an analog register.

Push the non-AR5416 related stuff into chipset specific directories.

sys/dev/ath/ath_hal/ar5416/ is getting very crowded and further
commits will make it even more crowded. Now is a good time to
shuffle these files out before any more extensive work is done
on them.

Create an ar9003 directory whilst I'm here; ar9003 specific
chipset code will eventually live there.

Revert part of the 9285 support because it breaks the 9280 support. I'll
try to do the 9285 support without interfering with any other chipset
revisions support.

Fix TX power problems with AR9285.

preliminary ar9280 support:
o add 9280 attach that sets up ini, cal, etc.
o new rf backend for 9280 and later parts
o split ini setup and spur mitigation support out to methods
and provide 9280-specific support
o minor fixups to shared code to handle 9280-specific work

Obtained from: Atheros (ini values and some code)