net: fill in MODULE_DESCRIPTION()s for DSA tags

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to all the DSA tag modules.

The descriptions are copy/pasted Kconfig names, with s/^Tag/DSA tag/.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Acked-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20240104143759.1318137-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: Use conduit and user terms

Use more inclusive terms throughout the DSA subsystem by moving away
from "master" which is replaced by "conduit" and "slave" which is
replaced by "user". No functional changes.

Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20231023181729.1191071-2-florian.fainelli@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: tag_qca: return early if dev is not found

Currently checksum is recalculated and dsa tag stripped even if we later
don't find the dev.

To improve code, exit early if we don't find the dev and skip additional
operation on the skb since it will be freed anyway.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20230730074113.21889-1-ansuelsmth@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net: dsa: move tagging protocol code to tag.{c,h}

It would be nice if tagging protocol drivers could include just the
header they need, since they are (mostly) data path and isolated from
most of the other DSA core code does.

Create a tag.c and a tag.h file which are meant to support tagging
protocol drivers.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: provide a second modalias to tag proto drivers based on their name

Currently, tagging protocol drivers have a modalias of
"dsa_tag:id-<number>", where the number is one of DSA_TAG_PROTO_*_VALUE.

This modalias makes it possible for the request_module() call in
dsa_tag_driver_get() to work, given the input it has - an integer
returned by ds->ops->get_tag_protocol().

It is also possible to change tagging protocols at (pseudo-)runtime, via
sysfs or via device tree, and this works via the name string of the
tagging protocol rather than via its id (DSA_TAG_PROTO_*_VALUE).

In the latter case, there is no request_module() call, because there is
no association that the DSA core has between the string name and the ID,
to construct the modalias. The module is simply assumed to have been
inserted. This is actually slightly problematic when the tagging
protocol change should take place at probe time, since it's expected
that the dependency module should get autoloaded.

For this purpose, let's introduce a second modalias, so that the DSA
core can call request_module() by name. There is no reason to make the
modalias by name optional, so just modify the MODULE_ALIAS_DSA_TAG_DRIVER()
macro to take both the ID and the name as arguments, and generate two
modaliases behind the scenes.

Suggested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc> # on kontron-sl28 w/ ocelot_8021q
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: tag_qca: add support for handling mgmt and MIB Ethernet packet

Add connect/disconnect helper to assign private struct to the DSA switch.
Add support for Ethernet mgmt and MIB if the DSA driver provide an handler
to correctly parse and elaborate the data.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_qca: add define for handling MIB packet

Add struct to correctly parse a mib Ethernet packet.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_qca: add define for handling mgmt Ethernet packet

Add all the required define to prepare support for mgmt read/write in
Ethernet packet. Any packet of this type has to be dropped as the only
use of these special packet is receive ack for an mgmt write request or
receive data for an mgmt read request.
A struct is used that emulates the Ethernet header but is used for a
different purpose.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_qca: enable promisc_on_master flag

Ethernet MDIO packets are non-standard and DSA master expects the first
6 octets to be the MAC DA. To address these kind of packet, enable
promisc_on_master flag for the tagger.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_qca: move define to include linux/dsa

Move tag_qca define to include dir linux/dsa as the qca8k require access
to the tagger define to support in-band mdio read/write using ethernet
packet.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_qca: convert to FIELD macro

Convert driver to FIELD macro to drop redundant define.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: create a helper for locating EtherType DSA headers on TX

Create a similar helper for locating the offset to the DSA header
relative to skb->data, and make the existing EtherType header taggers to
use it.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: create a helper for locating EtherType DSA headers on RX

It seems that protocol tagging driver writers are always surprised about
the formula they use to reach their EtherType header on RX, which
becomes apparent from the fact that there are comments in multiple
drivers that mention the same information.

Create a helper that returns a void pointer to skb->data - 2, as well as
centralize the explanation why that is the case.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: create a helper which allocates space for EtherType DSA headers

Hide away the memmove used by DSA EtherType header taggers to shift the
MAC SA and DA to the left to make room for the header, after they've
called skb_push(). The call to skb_push() is still left explicit in
drivers, to be symmetric with dsa_strip_etype_header, and because not
all callers can be refactored to do it (for example, brcm_tag_xmit_ll
has common code for a pre-Ethernet DSA tag and an EtherType DSA tag).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: create a helper that strips EtherType DSA headers on RX

All header taggers open-code a memmove that is fairly not all that
obvious, and we can hide the details behind a helper function, since the
only thing specific to the driver is the length of the header tag.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: remove the struct packet_type argument from dsa_device_ops::rcv()

No tagging driver uses this.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: generalize overhead for taggers that use both headers and trailers

Some really really weird switches just couldn't decide whether to use a
normal or a tail tagger, so they just did both.

This creates problems for DSA, because we only have the concept of an
'overhead' which can be applied to the headroom or to the tailroom of
the skb (like for example during the central TX reallocation procedure),
depending on the value of bool tail_tag, but not to both.

We need to generalize DSA to cater for these odd switches by
transforming the 'overhead / tail_tag' pair into 'needed_headroom /
needed_tailroom'.

The DSA master's MTU is increased to account for both.

The flow dissector code is modified such that it only calls the DSA
adjustment callback if the tagger has a non-zero header length.

Taggers are trivially modified to declare either needed_headroom or
needed_tailroom, based on the tail_tag value that they currently
declare.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_qca: let DSA core deal with TX reallocation

Now that we have a central TX reallocation procedure that accounts for
the tagger's needed headroom in a generic way, we can remove the
skb_cow_head call.

Cc: John Crispin <john@phrozen.org>
Cc: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: tag_qca: use the generic flow dissector procedure

Remove the .flow_dissect procedure, so the flow dissector will call the
generic variant which works for this tagging protocol.

Cc: John Crispin <john@phrozen.org>
Cc: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: make the .flow_dissect tagger callback return void

There is no tagger that returns anything other than zero, so just change
the return type appropriately.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_qca.c: Fix warning for __be16 vs u16

net/dsa/tag_qca.c:48:15: warning: incorrect type in assignment (different base types)
net/dsa/tag_qca.c:48:15: expected unsigned short [usertype]
net/dsa/tag_qca.c:48:15: got restricted __be16 [usertype]
net/dsa/tag_qca.c:68:13: warning: incorrect type in assignment (different base types)
net/dsa/tag_qca.c:68:13: expected restricted __be16 [usertype] hdr
net/dsa/tag_qca.c:68:13: got int
net/dsa/tag_qca.c:71:16: warning: restricted __be16 degrades to integer
net/dsa/tag_qca.c:81:17: warning: restricted __be16 degrades to integer

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_qca: Make sure there is headroom for tag

Passing tag size to skb_cow_head will make sure
there is enough headroom for the tag data.
This change does not introduce any overhead in case there
is already available headroom for tag.

Signed-off-by: Per Forlin <perfn@axis.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: tag_qca: fix doubled Tx statistics

DSA subsystem takes care of netdev statistics since commit 4ed70ce9f01c
("net: dsa: Refactor transmit path to eliminate duplication"), so
any accounting inside tagger callbacks is redundant and can lead to
messing up the stats.
This bug is present in Qualcomm tagger since day 0.

Fixes: cafdc45c949b ("net-next: dsa: add Qualcomm tag RX/TX handler")
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Alexander Lobakin <alobakin@dlink.ru>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Cleanup unneeded table and make tag structures static

Now that tag drivers dynamically register, we don't need the static
table. Remove it. This also means the tag driver structures can be
made static.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Add boilerplate helper to register DSA tag driver modules

A DSA tag driver module will need to register the tag protocols it
implements with the DSA core. Add macros containing this boiler plate.

The registration/unregistration code is currently just a stub. A Later
patch will add the real implementation.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

v2
Fix indent of #endif
Rewrite to move list pointer into a new structure
v3
Move kdoc next to macro
Fix THIS_MODULE indentation

Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Add TAG protocol to tag ops

In order that we can match the tagging protocol a switch driver
request to the tagger, we need to know what protocol the tagger
supports. Add this information to the ops structure.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

v2
More tag protocol to end of structure to keep hot members at the beginning.

Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Add MODULE_LICENSE to tag drivers

All the tag drivers are some variant of GPL. Add a MODULE_LICENSE()
indicating this, so the drivers can later be compiled as modules.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Add MODULE_ALIAS to taggers in preparation to become modules

When the tag drivers become modules, we will need to dynamically load
them based on what the switch drivers need. Add aliases to map between
the TAG protocol and the driver.

In order to do this, we need the tag protocol number as something
which the C pre-processor can stringinfy. Only the compiler knows the
value of an enum, CPP cannot use them. So add #defines.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Move tagger name into its ops structure

Rather than keep a list to map a tagger ops to a name, place the name
into the ops structure. This removes the hard coded list, a step
towards making the taggers more dynamic.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

v2:
Move name to end of structure, keeping the hot entries at the beginning.

Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: Add SPDX header to tag drivers.

Add an SPDX header, and remove the license boilerplate text.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Implement flow_dissect callback for tag_qca

Add flow_dissect for qca tagged packet to get the right hash.

Signed-off-by: Xiaofei Shen <xiaofeis@codeaurora.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Add overhead to tag protocol ops.

Each DSA tag protocol needs to add additional headers to the Ethernet
frame in order to direct it towards a specific switch egress port. It
must also remove the head from a frame received from a
switch. Indicate the maximum size of these headers in the tag protocol
ops structure, so the core can take these overheads into account.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: rename dsa_master_get_slave

The dsa_master_get_slave is slightly confusing since the idiomatic "get"
term often suggests reference counting, in symmetry to "put".

Rename it to dsa_master_find_slave to make the look up operation clear.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: add slave to port helper

Many portions of DSA core code require to get the dsa_port structure
corresponding to a slave net_device. For this purpose, introduce a
dsa_slave_to_port() helper.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: add master helper to look up slaves

The DSA tagging code does not need to know about the DSA architecture,
it only needs to return the slave device corresponding to the source
port index (and eventually the source device index for cascade-capable
switches) parsed from the frame received on the master device.

For this purpose, provide an inline dsa_master_get_slave helper which
validates the device and port indexes and look up the slave device.

This makes the tagging rcv functions more concise and robust, and also
makes dsa_get_cpu_port obsolete.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

dsa: remove unused net_device arg from handlers

compile tested only, but saw no warnings/errors with
allmodconfig build.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Introduce dsa_get_cpu_port()

Introduce a helper function which will return a reference to the CPU
port used in a dsa_switch_tree. Right now this is a singleton, but this
will change once we introduce multi-CPU port support, so ease the
transition by converting the affected code paths.

Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: factor skb freeing on xmit

As of a86d8becc3f0 ("net: dsa: Factor bottom tag receive functions"),
the rcv caller frees the original SKB in case or error.

Be symmetric with that and make the xmit caller do the same.

At the same time, fix the checkpatch NULL comparison check:

CHECK: Comparison to NULL could be written "!nskb"
#208: FILE: net/dsa/tag_trailer.c:35:
+ if (nskb == NULL)

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: remove out_drop label in taggers rcv

Many rcv functions from net/dsa/tag_*.c have a useless out_drop goto
label which simply returns NULL. Kill it in favor of the obvious.

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: include dsa.h only once

The public include/net/dsa.h file is meant for DSA drivers, while all
DSA core files share a common private header net/dsa/dsa_priv.h file.

Ensure that dsa_priv.h is the only DSA core file to include net/dsa.h,
and add a new line to separate absolute and relative headers at the same
time.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: store CPU port pointer in the tree

A dsa_switch_tree instance holds a dsa_switch pointer and a port index
to identify the switch port to which the CPU is attached.

Now that the DSA layer has a dsa_port structure to hold this data, use
it to point the switch CPU port.

This patch simply substitutes s/dst->cpu_switch/dst->cpu_dp->ds/ and
s/dst->cpu_port/dst->cpu_dp->index/.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Factor bottom tag receive functions

All DSA tag receive functions do strictly the same thing after they have located
the originating source port from their tag specific protocol:

- push ETH_HLEN bytes
- set pkt_type to PACKET_HOST
- call eth_type_trans()
- bump up counters
- call netif_receive_skb()

Factor all of that into dsa_switch_rcv(). This also makes us return a pointer to
a sk_buff, which makes us symetric with the xmit function.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Move skb_unshare() to dsa_switch_rcv()

All DSA tag receive functions need to unshare the skb before mangling it, move
this to the generic dsa_switch_rcv() function which will allow us to make the
tag receive function return their mangled skb without caring about freeing a
NULL skb.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Do not check for NULL dst in tag parsers

dsa_switch_rcv() already tests for dst == NULL, so there is no need to duplicate
the same check within the tag receive functions.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: break include loop netdevice.h, dsa.h, devlink.h

There is an include loop between netdevice.h, dsa.h, devlink.h because
of NETDEV_ALIGN, making it impossible to use devlink structures in
dsa.h.

Break this loop by taking dsa.h out of netdevice.h, add a forward
declaration of dsa_switch_tree and netdev_set_default_ethtool_ops()
function, which is what netdevice.h requires.

No longer having dsa.h in netdevice.h means the includes in dsa.h no
longer get included. This breaks a few other files which depend on
these includes. Add these directly in the affected file.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: store a dsa_port in dsa_slave_priv

Store a pointer to the dsa_port structure in the dsa_slave_priv
structure, instead of the switch/port index.

This will allow to store more information such as the bridge device,
needed in DSA drivers for multi-chip configuration.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: use cpu_switch instead of ds[0]

Now that the DSA Ethernet switches are true Linux devices, the CPU
switch is not necessarily the first one. If its address is higher than
the second switch on the same MDIO bus, its index will be 1, not 0.

Avoid any confusion by using dst->cpu_switch instead of dst->ds[0].

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net-next: dsa: add Qualcomm tag RX/TX handler

Add support for the 2-bytes Qualcomm tag that gigabit switches such as
the QCA8337/N might insert when receiving packets, or that we need
to insert while targeting specific switch ports. The tag is inserted
directly behind the ethernet header.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: David S. Miller <davem@davemloft.net>