qcom: add initial IPQ4018 MDIO support and etherswitch support

[adrian]

Summary

This adds support for the IPQ4018/IPQ4019 MDIO bus. This is used to
talk to external PHYs and switches. (There's an internal switch
in the IPQ4018/IPQ4019 as well, but it's accessible via MMIO/AXI.)

ar40xx_switch: add initial switch for the IPQ4018/IPQ4019.

This switch is based off of the AR8327/AR8337 external switch/PHY.
However unlike the AR8327/AR8337 it itself doesn't have any PHYs;
instead an external PHY connects to it using the PSGMII port.

This code is inspired by the ar40xx code in openwrt, which itself
is based on the Qualcomm QCA-SSDK. Both of these sources are, amusingly,
BSD licenced - and thus I have included some of the comments in the
hardware workaround paths to document some of the magic numbers.

[adrian]

sys/dev/etherswitch/ar40xx/ar40xx_debug.h

43

ugh lemme go wrap flags in parens here.

[adrian]

fix debug flags macro expansion

[manu]

Do you expect people to review a change that big ?

[adrian]

In D34096#771107, @manu wrote:

Do you expect people to review a change that big ?

(a) it's two commits, MDIO and etherswitch / DTS
(b) .. i mean it's a new driver, what should I do? :)

[manu]

In D34096#771123, @adrian wrote:

In D34096#771107, @manu wrote:

Do you expect people to review a change that big ?

(a) it's two commits, MDIO and etherswitch / DTS
(b) .. i mean it's a new driver, what should I do? :)

We don't see commits in phab.
Also I think that one commit for mdio, one for etherswitch, one for the binding, one for the dtsi, and for the dts change will be more clear.

[kevans]

In D34096#771124, @manu wrote:

In D34096#771123, @adrian wrote:

In D34096#771107, @manu wrote:

Do you expect people to review a change that big ?

(a) it's two commits, MDIO and etherswitch / DTS
(b) .. i mean it's a new driver, what should I do? :)

We don't see commits in phab.
Also I think that one commit for mdio, one for etherswitch, one for the binding, one for the dtsi, and for the dts change will be more clear.

+1. I recommend splitting it up then using git-arc to create 1:1 commit:review, it'll put them into a stack which almost doesn't suck

[adrian]

pull out the dts/include bits into a different commit in the stack

[adrian]

broke it up into three commits/reviews to make this easier

https://reviews.freebsd.org/D34110
https://reviews.freebsd.org/D34111
https://reviews.freebsd.org/D34112