alx: add msi-x support

Add msi-x support to the alx driver. This is in preparation for multi queue
support.

msi-x interrupts are disabled by default because without multi queue support
there is no advantage over msi interrupts. The performance numbers observed
with iperf stay the same.

Based on information of the downstream driver at github.com/qca/alx

Signed-off-by: Tobias Regnery <tobias.regnery@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ethernet/atheros/alx: sanitize buffer sizing and padding

This is based on the work done by Przemek Rudy in bug 70761 at
bugzilla.kernel.org, but with some work done to disentagle and clarify
things a bit.

Similar to Przemek's work and other drivers, we're adding a padding of 16
here, but we're also disentangling mtu size calculations from max buffer
size calculations a bit, and adding ETH_HLEN to the value written into
ALX_MTU. Hopefully, with a bit more consistency and clarity, things behave
better here. Sadly, I can only test in my alx-driven E2200, which worked
just fine before this patch.

In comment #58 of bug 70761, Eugene A. Shatokhin reports that this patch
does help considerably for a ROSA Linux user of his with an AR8162 network
adapter when patched into a 4.1.x-based kernel, with several days of
normal operation where wired network previously wasn't usable without
setting MTU to 9000 as a work-around.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=70761
CC: "Eugene A. Shatokhin" <eugene.shatokhin@rosalab.ru>
CC: Przemek Rudy <prudy1@o2.pl>
CC: Jay Cliburn <jcliburn@gmail.com>
CC: Chris Snook <chris.snook@gmail.com>
CC: netdev@vger.kernel.org
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

alx: add stats update function

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

alx: remove WoL support

Unfortunately, WoL is broken and the system will immediately
resume after suspending, and I can't seem to figure out why.
Remove WoL support until the issue can be found.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

alx: fix MAC address alignment problem

In two places, parts of MAC addresses are used as u32/u16
values. This can cause alignment problems, use put_unaligned
and get_unaligned to fix this.

Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

alx: separate link speed/duplex fields

As suggested by Ben Hutchings, use separate fields to track
current link speed and duplex setting.

Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

alx: fix 100mbit/half duplex speed translation

100mbit half duplex is ADVERTISED_100baseT_Half, not
ADVERTISED_10baseT_Half.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

alx: add a simple AR816x/AR817x device driver

This is a very simple driver, based on the original vendor
driver that Qualcomm/Atheros published/submitted previously,
but reworked to make the code saner. However, it also lost
a number of features (TSO/GSO, VLAN acceleration and multi-
queue support) in the process, as well as debugging support
features I didn't have any use for. The only thing I left
is checksum offload.

More features can obviously be added, but this seemed like
a good start for having a driver in mainline at all.

Johannes Stezenbach has verified that the driver works on
AR8161, I have a AR8171 myself. The E2200 device ID I found
on github in somebody's repository.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>