Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

[mdio] migrate mdiobus out of etherswitch and into a top-level device of its own.

The mdio driver interface is generally useful for devices that require
MDIO without the full MII bus interface. This lifts the driver/interface
out of etherswitch(4), and adds a mdio(4) man page.

Submitted by: Landon Fuller <landon@landonf.org>
Differential Revision: https://reviews.freebsd.org/D4606

Fix up support for the AR8327.

* Even though I got the registers around "right", it seems
I'm not tickling the MDIO access correctly for the internal PHY
bus. Some of the switches are fine poking at the external PHY
registers; others aren't. So, enable direct PHY bus access
for the AR8327, and leave the existing code in place for the
others.

* Go and shuffle the register access around. Whilst here,
restore the 2ms delay if changing page.

* Comment out some of the stub printf()s; there's some upcoming
work to add port VLAN support.

Tested:

* AP135 development board
* Carambola2 - AR9331 SoC

Revert r268543.

We should probably fix sys/gpio.h instead.

Move iic.h to sys/ so that it's automatically installed in /usr/include/sys.

This lets us call iic(4) ioctls without needing the kernel source code
and follows the same model of GPIO.

MFC after: 3 weeks

Teach the PHY register path about the different MDIO bus address
for the AR8327.

Tested:

* AR8327, DB120

- Provide necessary includes, that before came via if.h pollution.
- Remove unnecessary ones.

Sponsored by: Netflix
Sponsored by: Nginx, Inc.

Fix the arswitch instability problem. It turns out that the
arswitch_writereg() routine was writing the registers in the wrong order.

Revert -r241918 as the root problem is now fixed. Remove another workaround
from arswitch_ar7240.c.

Simplify and fix the code on arswitch_writephy() by using
arswitch_writereg().

While here remove a redundant declaration from arswitchvar.h.

Approved by: adrian (mentor)

Locking for etherswitch framework:
* add lock/unlock methods;
* add lock/unlock default implementation;
* surround switch IOCTLs with locking;
* add lock/unlock implementation for arswitch;

Submitted by: Luiz Otavio O Souza
Approved by: adrian (mentor)

Commit the first pass of the etherswitch support.

This is designed to support the very basic ethernet switch chip behaviour,
specifically:

* accessing switch register space;
* accessing per-PHY registers (for switches that actually expose PHYs);
* basic vlan group support, which applies for the rtl8366 driver but not
for the atheros switches.

This also includes initial support for:

* rtl8366rb support - which is a 10/100/1000 switch which supports
vlan groups;
* Initial Atheros AR8316 switch support - which is a 10/100/1000 switch
which supports an alternate vlan configuration (so the vlan group
methods are stubbed.)

The general idea here is that the switch driver may speak to a variety of
backend busses (mdio, i2c, spi, whatever) and expose:

* If applicable, one or more MDIO busses which ethernet interfaces can
then attach PHYs to via miiproxy/mdioproxy;

* exposes miibusses, one for each port at the moment, so ..

* .. a PHY can be exposed on each miibus, for each switch port, with all
of the existing MII/ifnet framework.

However:

* The ifnet is manually created for now, and it isn't linked into the
interface list, nor can you (currently) send/receive frames on this ifnet.
At some point in the future there may be _some_ support for this, for
switches with a multi-port, isolated mode.

* I'm still in the process of sorting out correct(er) locking.

TODO:

* ray's switch code in zrouter (zrouter.org) includes a much more developed
newbus API that covers the various switch methods, as well as a
capability API so drivers, the switch layer and the userland utility
can properly control the subset of supported features.

The plan is to sort that out later, once the rest of ray's switch drivers
are brought over and extended to export MII busses and PHYs.

Submitted by: Stefan Bethke <stb@lassitu.de>
Reviewed by: ray