Add basic support for MRP. The HW will just trap all MRP frames on the
ring ports to CPU and allow the SW to process them. In this way it is
possible to for this node to behave both as MRM and MRC.

Current limitations are:
- it doesn't support Interconnect roles.
- it supports only a single ring.
- the HW should be able to do forwarding of MRP Test frames so the SW
  will not need to do this. So it would be able to have the role MRC
  without SW support.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

For TX timestamping, we use the felix_txtstamp method which is common
with the regular (non-8021q) ocelot tagger. This method says that skb
deferral is needed, prepares a timestamp request ID, and puts a clone of
the skb in a queue waiting for the timestamp IRQ.

felix_txtstamp is called by dsa_skb_tx_timestamp() just before the
tagger's xmit method. In the tagger xmit, we divert the packets
classified by dsa_skb_tx_timestamp() as PTP towards the MMIO-based
injection registers, and we declare them as dead towards dsa_slave_xmit.
If not PTP, we proceed with normal tag_8021q stuff.

Then the timestamp IRQ fires, the clone queued up from felix_txtstamp is
matched to the TX timestamp retrieved from the switch's FIFO based on
the timestamp request ID, and the clone is delivered to the stack.

On RX, thanks to the VCAP IS2 rule that redirects the frames with an
EtherType for 1588 towards two destinations:
- the CPU port module (for MMIO based extraction) and
- if the "no XTR IRQ" workaround is in place, the dsa_8021q CPU port
the relevant data path processing starts in the ptp_classify_raw BPF
classifier installed by DSA in the RX data path (post tagger, which is
completely unaware that it saw a PTP packet).

This time we can't reuse the same implementation of .port_rxtstamp that
also works with the default ocelot tagger. That is because felix_rxtstamp
is given an skb with a freshly stripped DSA header, and it says "I don't
need deferral for its RX timestamp, it's right in it, let me show you";
and it just points to the header right behind skb->data, from where it
unpacks the timestamp and annotates the skb with it.

The same thing cannot happen with tag_ocelot_8021q, because for one
thing, the skb did not have an extraction frame header in the first
place, but a VLAN tag with no timestamp information. So the code paths
in felix_rxtstamp for the regular and 8021q tagger are completely
independent. With tag_8021q, the timestamp must come from the packet's
duplicate delivered to the CPU port module, but there is potentially
complex logic to be handled [ and prone to reordering ] if we were to
just start reading packets from the CPU port module, and try to match
them to the one we received over Ethernet and which needs an RX
timestamp. So we do something simple: we tell DSA "give me some time to
think" (we request skb deferral by returning false from .port_rxtstamp)
and we just drop the frame we got over Ethernet with no attempt to match
it to anything - we just treat it as a notification that there's data to
be processed from the CPU port module's queues. Then we proceed to read
the packets from those, one by one, which we deliver up the stack,
timestamped, using netif_rx - the same function that any driver would
use anyway if it needed RX timestamp deferral. So the assumption is that
we'll come across the PTP packet that triggered the CPU extraction
notification eventually, but we don't know when exactly. Thanks to the
VCAP IS2 trap/redirect rule and the exclusion of the CPU port module
from the flooding replicators, only PTP frames should be present in the
CPU port module's RX queues anyway.

There is just one conflict between the VCAP IS2 trapping rule and the
semantics of the BPF classifier. Namely, ptp_classify_raw() deems
general messages as non-timestampable, but still, those are trapped to
the CPU port module since they have an EtherType of ETH_P_1588. So, if
the "no XTR IRQ" workaround is in place, we need to run another BPF
classifier on the frames extracted over MMIO, to avoid duplicates being
sent to the stack (once over Ethernet, once over MMIO). It doesn't look
like it's possible to install VCAP IS2 rules based on keys extracted
from the 1588 frame headers.

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

Since the felix DSA driver will need to poll the CPU port module for
extracted frames as well, let's create some common functions that read
an Extraction Frame Header, and then an skb, from a CPU extraction
group.

We abuse the struct ocelot_ops :: port_to_netdev function a little bit,
in order to retrieve the DSA port net_device or the ocelot switchdev
net_device based on the source port information from the Extraction
Frame Header, but it's all in the benefit of code simplification -
netdev_alloc_skb needs it. Originally, the port_to_netdev method was
intended for parsing act->dev from tc flower offload code.

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

The Injection Frame Header and Extraction Frame Header that the switch
prepends to frames over the NPI port is also prepended to frames
delivered over the CPU port module's queues.

Let's unify the handling of the frame headers by making the ocelot
driver call some helpers exported by the DSA tagger. Among other things,
this allows us to get rid of the strange cpu_to_be32 when transmitting
the Injection Frame Header on ocelot, since the packing API uses
network byte order natively (when "quirks" is 0).

The comments above ocelot_gen_ifh talk about setting pop_cnt to 3, and
the cpu extraction queue mask to something, but the code doesn't do it,
so we don't do it either.

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

The felix DSA driver will inject some frames through register MMIO, same
as ocelot switchdev currently does. So we need to be able to reuse the
common code.

Also create some shim definitions, since the DSA tagger can be compiled
without support for the switch driver.

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

We should not be unconditionally enabling address learning, since doing
that is actively detrimential when a port is standalone and not offloading
a bridge. Namely, if a port in the switch is standalone and others are
offloading the bridge, then we could enter a situation where we learn an
address towards the standalone port, but the bridged ports could not
forward the packet there, because the CPU is the only path between the
standalone and the bridged ports. The solution of course is to not
enable address learning unless the bridge asks for it.

We need to set up the initial port flags for no learning and flooding
everything, and also when the port joins and leaves the bridge.
The flood configuration was already configured ok for standalone mode
in ocelot_init, we just need to disable learning in ocelot_init_port.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In preparation of offloading the bridge port flags which have
independent settings for unknown multicast and for broadcast, we should
also start reserving one destination Port Group ID for the flooding of
broadcast packets, to allow configuring it individually.

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

There are several issues which may be seen when the link goes down while
forwarding traffic, all of which can be attributed to the fact that the
port flushing procedure from the reference manual was not closely
followed.

With flow control enabled on both the ingress port and the egress port,
it may happen when a link goes down that Ethernet packets are in flight.
In flow control mode, frames are held back and not dropped. When there
is enough traffic in flight (example: iperf3 TCP), then the ingress port
might enter congestion and never exit that state. This is a problem,
because it is the egress port's link that went down, and that has caused
the inability of the ingress port to send packets to any other port.
This is solved by flushing the egress port's queues when it goes down.

There is also a problem when performing stream splitting for
IEEE 802.1CB traffic (not yet upstream, but a sort of multicast,
basically). There, if one port from the destination ports mask goes
down, splitting the stream towards the other destinations will no longer
be performed. This can be traced down to this line:

	ocelot_port_writel(ocelot_port, 0, DEV_MAC_ENA_CFG);

which should have been instead, as per the reference manual:

	ocelot_port_rmwl(ocelot_port, 0, DEV_MAC_ENA_CFG_RX_ENA,
			 DEV_MAC_ENA_CFG);

Basically only DEV_MAC_ENA_CFG_RX_ENA should be disabled, but not
DEV_MAC_ENA_CFG_TX_ENA - I don't have further insight into why that is
the case, but apparently multicasting to several ports will cause issues
if at least one of them doesn't have DEV_MAC_ENA_CFG_TX_ENA set.

I am not sure what the state of the Ocelot VSC7514 driver is, but
probably not as bad as Felix/Seville, since VSC7514 uses phylib and has
the following in ocelot_adjust_link:

	if (!phydev->link)
		return;

therefore the port is not really put down when the link is lost, unlike
the DSA drivers which use .phylink_mac_link_down for that.

Nonetheless, I put ocelot_port_flush() in the common ocelot.c because it
needs to access some registers from drivers/net/ethernet/mscc/ocelot_rew.h
which are not exported in include/soc/mscc/ and a bugfix patch should
probably not move headers around.

Fixes: bdeced75b13f ("net: dsa: felix: Add PCS operations for PHYLINK")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The ocelot switch has been supporting LAG offload since its initial
commit, however felix could not make use of that, due to lack of a LAG
abstraction in DSA. Now that we have that, let's forward DSA's calls
towards the ocelot library, who will deal with setting up the bonding.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>