[PATCH net 0/3] net: dsa: mv88e6xxx: fix hardware cross-chip bridging

[PATCH net 0/3] net: dsa: mv88e6xxx: fix hardware cross-chip bridging

[Vivien Didelot]

In order to accelerate cross-chip switching of frames with the hardware,
the DSA Tag ports, used to interconnect switch devices, must learn SA
and DA addresses, and share the same FDB with the user ports.

The two first patches restore address learning on DSA links. This fixes
hardware cross-chip bridging in a VLAN filtering enabled system, which
implements a bridge group as a 802.1Q VLAN and thus share an isolated
address database between DSA and user ports.

The third patch changes the distinct default databases used for each
port, to the same address database. This fixes the hardware cross-chip
bridging in a VLAN filtering disabled system, where a bridge group gets
implemented only as a port-based VLAN.

Vivien Didelot (3):
  net: dsa: mv88e6xxx: unlock DSA and CPU ports
  net: dsa: mv88e6xxx: enable SA learning on DSA ports
  net: dsa: mv88e6xxx: share a default FDB

 drivers/net/dsa/mv88e6xxx.c | 34 +++++-----------------------------
 1 file changed, 5 insertions(+), 29 deletions(-)

-- 
2.8.0

[PATCH net 1/3] net: dsa: mv88e6xxx: unlock DSA and CPU ports

[Vivien Didelot]

Locking a port generates an hardware interrupt when a new SA address is
received. This enables CPU directed learning, which is needed for 802.1X
MAC authentication.

To disable automatic learning on a port, the only configuration needed
is to set its Port Association Vector to all zero.

Clear PAV when SA learning should be disabled instead of locking a port.

Fixes: 4c7ea3c0791e ("net: dsa: mv88e6xxx: disable SA learning for DSA and CPU ports")
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
---
 drivers/net/dsa/mv88e6xxx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
index 9985a0c..7725e29 100644
--- a/drivers/net/dsa/mv88e6xxx.c
+++ b/drivers/net/dsa/mv88e6xxx.c
@@ -2544,7 +2544,7 @@ static int mv88e6xxx_setup_port(struct dsa_switch *ds, int port)
 	reg = 1 << port;
 	/* Disable learning for DSA and CPU ports */
 	if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))
-		reg = PORT_ASSOC_VECTOR_LOCKED_PORT;
+		reg = 0;
 
 	ret = _mv88e6xxx_reg_write(ds, REG_PORT(port), PORT_ASSOC_VECTOR, reg);
 	if (ret)
-- 
2.8.0

[PATCH net 2/3] net: dsa: mv88e6xxx: enable SA learning on DSA ports

[Vivien Didelot]

In multi-chip systems, DSA Tag ports must learn SA addresses in order to
correctly switch frames between interconnected chips.

This fixes cross-chip hardware bridging in a VLAN filtering aware
system, because a bridge group gets implemented as an hardware 802.1Q
VLAN and thus DSA and user ports share the same FDB.

Fixes: 4c7ea3c0791e ("net: dsa: mv88e6xxx: disable SA learning for DSA and CPU ports")
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
---
 drivers/net/dsa/mv88e6xxx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
index 7725e29..46c9b4c 100644
--- a/drivers/net/dsa/mv88e6xxx.c
+++ b/drivers/net/dsa/mv88e6xxx.c
@@ -2542,8 +2542,8 @@ static int mv88e6xxx_setup_port(struct dsa_switch *ds, int port)
 	 * the other bits clear.
 	 */
 	reg = 1 << port;
-	/* Disable learning for DSA and CPU ports */
-	if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))
+	/* Disable learning for CPU port */
+	if (dsa_is_cpu_port(ds, port))
 		reg = 0;
 
 	ret = _mv88e6xxx_reg_write(ds, REG_PORT(port), PORT_ASSOC_VECTOR, reg);
-- 
2.8.0

[PATCH net 3/3] net: dsa: mv88e6xxx: share the same default FDB

[Vivien Didelot]

For hardware cross-chip bridging to work, user ports *and* DSA ports
need to share a common address database, in order to switch a frame to
the correct interconnected device.

This is currently working for VLAN filtering aware systems, since Linux
will implement a bridge group as a 802.1Q VLAN, which has its own FDB,
including DSA and CPU links as members.

However when the system doesn't support VLAN filtering, Linux only
relies on the port-based VLAN to implement a bridge group.

To fix hardware cross-chip bridging for such systems, set the same
default address database 0 for user and DSA ports, instead of giving
them all a different default database.

Note that the bridging code prevents frames to egress between unbridged
ports, and flushes FDB entries of a port when changing its STP state.

Also note that the FID 0 is special and means "all" for ATU operations,
but it's OK since it is used as a default forwarding address database.

Fixes: 2db9ce1fd9a3 ("net: dsa: mv88e6xxx: assign default FDB to ports")
Fixes: 466dfa077022 ("net: dsa: mv88e6xxx: assign dynamic FDB to bridges")
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
---
 drivers/net/dsa/mv88e6xxx.c | 28 ++--------------------------
 1 file changed, 2 insertions(+), 26 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
index 46c9b4c..b76f870 100644
--- a/drivers/net/dsa/mv88e6xxx.c
+++ b/drivers/net/dsa/mv88e6xxx.c
@@ -2246,27 +2246,10 @@ int mv88e6xxx_port_bridge_join(struct dsa_switch *ds, int port,
 			       struct net_device *bridge)
 {
 	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
-	u16 fid;
 	int i, err;
 
 	mutex_lock(&ps->smi_mutex);
 
-	/* Get or create the bridge FID and assign it to the port */
-	for (i = 0; i < ps->num_ports; ++i)
-		if (ps->ports[i].bridge_dev == bridge)
-			break;
-
-	if (i < ps->num_ports)
-		err = _mv88e6xxx_port_fid_get(ds, i, &fid);
-	else
-		err = _mv88e6xxx_fid_new(ds, &fid);
-	if (err)
-		goto unlock;
-
-	err = _mv88e6xxx_port_fid_set(ds, port, fid);
-	if (err)
-		goto unlock;
-
 	/* Assign the bridge and remap each port's VLANTable */
 	ps->ports[port].bridge_dev = bridge;
 
@@ -2278,7 +2261,6 @@ int mv88e6xxx_port_bridge_join(struct dsa_switch *ds, int port,
 		}
 	}
 
-unlock:
 	mutex_unlock(&ps->smi_mutex);
 
 	return err;
@@ -2288,16 +2270,10 @@ void mv88e6xxx_port_bridge_leave(struct dsa_switch *ds, int port)
 {
 	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
 	struct net_device *bridge = ps->ports[port].bridge_dev;
-	u16 fid;
 	int i;
 
 	mutex_lock(&ps->smi_mutex);
 
-	/* Give the port a fresh Filtering Information Database */
-	if (_mv88e6xxx_fid_new(ds, &fid) ||
-	    _mv88e6xxx_port_fid_set(ds, port, fid))
-		netdev_warn(ds->ports[port], "failed to assign a new FID\n");
-
 	/* Unassign the bridge and remap each port's VLANTable */
 	ps->ports[port].bridge_dev = NULL;
 
@@ -2624,11 +2600,11 @@ static int mv88e6xxx_setup_port(struct dsa_switch *ds, int port)
 	if (ret)
 		goto abort;
 
-	/* Port based VLAN map: give each port its own address
+	/* Port based VLAN map: give each port the same default address
 	 * database, and allow bidirectional communication between the
 	 * CPU and DSA port(s), and the other ports.
 	 */
-	ret = _mv88e6xxx_port_fid_set(ds, port, port + 1);
+	ret = _mv88e6xxx_port_fid_set(ds, port, 0);
 	if (ret)
 		goto abort;
 
-- 
2.8.0

Re: [PATCH net 0/3] net: dsa: mv88e6xxx: fix hardware cross-chip bridging

[David Miller]

From: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Date: Thu, 14 Apr 2016 14:42:06 -0400

> In order to accelerate cross-chip switching of frames with the hardware,
> the DSA Tag ports, used to interconnect switch devices, must learn SA
> and DA addresses, and share the same FDB with the user ports.
> 
> The two first patches restore address learning on DSA links. This fixes
> hardware cross-chip bridging in a VLAN filtering enabled system, which
> implements a bridge group as a 802.1Q VLAN and thus share an isolated
> address database between DSA and user ports.
> 
> The third patch changes the distinct default databases used for each
> port, to the same address database. This fixes the hardware cross-chip
> bridging in a VLAN filtering disabled system, where a bridge group gets
> implemented only as a port-based VLAN.

Series applied, thanks.