[PATCH net-next v2 0/5] net: dsa: add cross-chip VLAN support

The current code in DSA does not support cross-chip VLAN. This means
that in a multi-chip environment such as this one (similar to ZII Rev B)

         [CPU].................... (mdio)
    (eth0) |   :       :          :
          _|_____    _______    _______
         [__sw0__]--[__sw1__]--[__sw2__]
          |  |  |    |  |  |    |  |  |
          v  v  v    v  v  v    v  v  v
          p1 p2 p3   p4 p5 p6   p7 p8 p9 

adding a VLAN to p9 won't be enough to reach the CPU, until at least one
port of sw0 and sw1 join the VLAN as well and become aware of the VID.

This patchset makes the DSA core program the VLAN on the CPU and DSA
links itself, which brings seamlessly cross-chip VLAN support to DSA.

With this series applied*, the hardware VLAN tables of a 3-switch setup
look like this after adding a VLAN to only one port of the end switch:

    # cat /sys/class/net/br0/bridge/default_pvid 
    42
    # cat /sys/kernel/debug/mv88e6xxx/sw{0,1,2}/vtu
    # ip link set up master br0 dev lan6
    # cat /sys/kernel/debug/mv88e6xxx/sw{0,1,2}/vtu
     VID  FID  SID  0  1  2  3  4  5  6
      42    1    0  x  x  x  x  x  =  =
     VID  FID  SID  0  1  2  3  4  5  6
      42    1    0  x  x  x  x  x  =  =
     VID  FID  SID  0  1  2  3  4  5  6  7  8  9
      42    1    0  u  x  x  x  x  x  x  x  x  =

('x' is excluded, 'u' is untagged, '=' is unmodified DSA and CPU ports.)

Completely removing a VLAN entry (which is currently the responsibility
of drivers anyway) is not supported yet since it requires some caching.

(*) the output is shown from this out-of-tree debugfs patch:
https://github.com/vivien/linux/commit/7b61a684b9d6b6a499135a587c7f62a1fddceb8b.patch

Changes in v2:
  - canonical incrementation (port++ instead of ++port)
  - check CPU and DSA ports before purging a VLAN
  - add Reviewed-by tags

Vivien Didelot (5):
  net: dsa: mv88e6xxx: define membership on VLAN add
  net: dsa: check VLAN capability of every switch
  net: dsa: add CPU and DSA ports as VLAN members
  net: dsa: mv88e6xxx: exclude all ports in new VLAN
  net: dsa: mv88e6xxx: do not skip ports on VLAN del

 drivers/net/dsa/mv88e6xxx/chip.c | 27 ++++++++++++++-------------
 net/dsa/switch.c                 | 30 ++++++++++++++++++++----------
 2 files changed, 34 insertions(+), 23 deletions(-)

-- 
2.13.1

Define the target port membership of the VLAN entry in
mv88e6xxx_port_vlan_add where ds is scoped.

Allow the DSA core to call later the port_vlan_add operation for CPU or
DSA ports, by using the Unmodified membership for these ports, as in the
current behavior.

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vivien Didelot <redacted>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 44c87027623b..962b4e873bf9 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c

@@ -1274,7 +1274,7 @@ mv88e6xxx_port_vlan_prepare(struct dsa_switch *ds, int port,
 }
 
 static int _mv88e6xxx_port_vlan_add(struct mv88e6xxx_chip *chip, int port,
-				    u16 vid, bool untagged)
+				    u16 vid, u8 member)
 {
 	struct mv88e6xxx_vtu_entry vlan;
 	int err;

@@ -1283,9 +1283,7 @@ static int _mv88e6xxx_port_vlan_add(struct mv88e6xxx_chip *chip, int port,
 	if (err)
 		return err;
 
-	vlan.member[port] = untagged ?
-		GLOBAL_VTU_DATA_MEMBER_TAG_UNTAGGED :
-		GLOBAL_VTU_DATA_MEMBER_TAG_TAGGED;
+	vlan.member[port] = member;
 
 	return mv88e6xxx_vtu_loadpurge(chip, &vlan);
 }

@@ -1297,15 +1295,23 @@ static void mv88e6xxx_port_vlan_add(struct dsa_switch *ds, int port,
 	struct mv88e6xxx_chip *chip = ds->priv;
 	bool untagged = vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED;
 	bool pvid = vlan->flags & BRIDGE_VLAN_INFO_PVID;
+	u8 member;
 	u16 vid;
 
 	if (!chip->info->max_vid)
 		return;
 
+	if (dsa_is_dsa_port(ds, port) || dsa_is_cpu_port(ds, port))
+		member = GLOBAL_VTU_DATA_MEMBER_TAG_UNMODIFIED;
+	else if (untagged)
+		member = GLOBAL_VTU_DATA_MEMBER_TAG_UNTAGGED;
+	else
+		member = GLOBAL_VTU_DATA_MEMBER_TAG_TAGGED;
+
 	mutex_lock(&chip->reg_lock);
 
 	for (vid = vlan->vid_begin; vid <= vlan->vid_end; ++vid)
-		if (_mv88e6xxx_port_vlan_add(chip, port, vid, untagged))
+		if (_mv88e6xxx_port_vlan_add(chip, port, vid, member))
 			netdev_err(ds->ports[port].netdev,
 				   "failed to add VLAN %d%c\n",
 				   vid, untagged ? 'u' : 't');

-- 
2.13.1

In a multi-chip switch fabric, it is currently the responsibility of the
driver to add the CPU or DSA (interconnecting chips together) ports as
members of a new VLAN entry. This makes the drivers more complicated.

We want the DSA drivers to be stupid and the DSA core being the one
responsible for caring about the abstracted switch logic and topology.

Make the DSA core program the CPU and DSA ports as part of the VLAN.

This makes all chips of the data path to be aware of VIDs spanning the
the whole fabric and thus, seamlessly add support for cross-chip VLAN.

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vivien Didelot <redacted>
---
 net/dsa/switch.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/dsa/switch.c b/net/dsa/switch.c
index f235ae1e9777..f1029a8d0e20 100644
--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c

@@ -166,6 +166,9 @@ static int dsa_switch_vlan_add(struct dsa_switch *ds,
 	bitmap_zero(members, ds->num_ports);
 	if (ds->index == info->sw_index)
 		set_bit(info->port, members);
+	for (port = 0; port < ds->num_ports; port++)
+		if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))
+			set_bit(port, members);
 
 	if (switchdev_trans_ph_prepare(trans)) {
 		if (!ds->ops->port_vlan_prepare || !ds->ops->port_vlan_add)

-- 
2.13.1

Now that the VLAN object is propagated to every switch chip of the
switch fabric, we can easily ensure that they all support the required
VLAN operations before modifying an entry on a single switch.

To achieve that, remove the condition skipping other target switches,
and add a bitmap of VLAN members, eventually containing the target port,
if we are programming the switch target.

This will allow us to easily add other VLAN members, such as the DSA or
CPU ports (to introduce cross-chip VLAN support) or the other port
members if we want to reduce hardware accesses later.

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vivien Didelot <redacted>
---
 net/dsa/switch.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/net/dsa/switch.c b/net/dsa/switch.c
index d8e5c311ee7c..f235ae1e9777 100644
--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c

@@ -159,19 +159,27 @@ static int dsa_switch_vlan_add(struct dsa_switch *ds,
 {
 	const struct switchdev_obj_port_vlan *vlan = info->vlan;
 	struct switchdev_trans *trans = info->trans;
+	DECLARE_BITMAP(members, ds->num_ports);
+	int port, err;
 
-	/* Do not care yet about other switch chips of the fabric */
-	if (ds->index != info->sw_index)
-		return 0;
+	/* Build a mask of VLAN members */
+	bitmap_zero(members, ds->num_ports);
+	if (ds->index == info->sw_index)
+		set_bit(info->port, members);
 
 	if (switchdev_trans_ph_prepare(trans)) {
 		if (!ds->ops->port_vlan_prepare || !ds->ops->port_vlan_add)
 			return -EOPNOTSUPP;
 
-		return ds->ops->port_vlan_prepare(ds, info->port, vlan, trans);
+		for_each_set_bit(port, members, ds->num_ports) {
+			err = ds->ops->port_vlan_prepare(ds, port, vlan, trans);
+			if (err)
+				return err;
+		}
 	}
 
-	ds->ops->port_vlan_add(ds, info->port, vlan, trans);
+	for_each_set_bit(port, members, ds->num_ports)
+		ds->ops->port_vlan_add(ds, port, vlan, trans);
 
 	return 0;
 }

@@ -181,14 +189,13 @@ static int dsa_switch_vlan_del(struct dsa_switch *ds,
 {
 	const struct switchdev_obj_port_vlan *vlan = info->vlan;
 
-	/* Do not care yet about other switch chips of the fabric */
-	if (ds->index != info->sw_index)
-		return 0;
-
 	if (!ds->ops->port_vlan_del)
 		return -EOPNOTSUPP;
 
-	return ds->ops->port_vlan_del(ds, info->port, vlan);
+	if (ds->index == info->sw_index)
+		return ds->ops->port_vlan_del(ds, info->port, vlan);
+
+	return 0;
 }
 
 static int dsa_switch_event(struct notifier_block *nb,

-- 
2.13.1

The mv88e6xxx driver currently tries to be smart and remove by itself a
VLAN entry from the VTU when the driven switch sees no user ports as
members of the VLAN.

This is bad in a multi-chip switch fabric, since a chip in between
others may have no bridge port members, but still needs to be aware of
the VID in order to correctly pass frames in the data path.

Now that the DSA core explicitly manages DSA and CPU ports, do not skip
them when checking remaining VLAN members.

Signed-off-by: Vivien Didelot <redacted>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 41202b1d6d7f..0534eb706caa 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c

@@ -1325,7 +1325,6 @@ static void mv88e6xxx_port_vlan_add(struct dsa_switch *ds, int port,
 static int _mv88e6xxx_port_vlan_del(struct mv88e6xxx_chip *chip,
 				    int port, u16 vid)
 {
-	struct dsa_switch *ds = chip->ds;
 	struct mv88e6xxx_vtu_entry vlan;
 	int i, err;
 

@@ -1342,9 +1341,6 @@ static int _mv88e6xxx_port_vlan_del(struct mv88e6xxx_chip *chip,
 	/* keep the VLAN unless all ports are excluded */
 	vlan.valid = false;
 	for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
-		if (dsa_is_cpu_port(ds, i) || dsa_is_dsa_port(ds, i))
-			continue;
-
 		if (vlan.member[i] != GLOBAL_VTU_DATA_MEMBER_TAG_NON_MEMBER) {
 			vlan.valid = true;
 			break;

-- 
2.13.1

Now that the DSA core adds the CPU and DSA ports itself to the new VLAN
entry, there is no need to include them as members of this VLAN when
initializing a new VTU entry.

As of now, initialize a new VTU entry with all ports excluded.

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vivien Didelot <redacted>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 962b4e873bf9..41202b1d6d7f 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c

@@ -1159,11 +1159,10 @@ static int mv88e6xxx_vtu_get(struct mv88e6xxx_chip *chip, u16 vid,
 		entry->valid = true;
 		entry->vid = vid;
 
-		/* Include only CPU and DSA ports */
+		/* Exclude all ports */
 		for (i = 0; i < mv88e6xxx_num_ports(chip); ++i)
-			entry->member[i] = dsa_is_normal_port(chip->ds, i) ?
-				GLOBAL_VTU_DATA_MEMBER_TAG_NON_MEMBER :
-				GLOBAL_VTU_DATA_MEMBER_TAG_UNMODIFIED;
+			entry->member[i] =
+				GLOBAL_VTU_DATA_MEMBER_TAG_NON_MEMBER;
 
 		return mv88e6xxx_atu_new(chip, &entry->fid);
 	}

-- 
2.13.1

From: Vivien Didelot <redacted>
Date: Wed,  7 Jun 2017 18:12:12 -0400

The current code in DSA does not support cross-chip VLAN. This means
that in a multi-chip environment such as this one (similar to ZII Rev B)

 ...

adding a VLAN to p9 won't be enough to reach the CPU, until at least one
port of sw0 and sw1 join the VLAN as well and become aware of the VID.

This patchset makes the DSA core program the VLAN on the CPU and DSA
links itself, which brings seamlessly cross-chip VLAN support to DSA.

With this series applied*, the hardware VLAN tables of a 3-switch setup
look like this after adding a VLAN to only one port of the end switch:

  ...

Completely removing a VLAN entry (which is currently the responsibility
of drivers anyway) is not supported yet since it requires some caching.

(*) the output is shown from this out-of-tree debugfs patch:
https://github.com/vivien/linux/commit/7b61a684b9d6b6a499135a587c7f62a1fddceb8b.patch

Changes in v2:
  - canonical incrementation (port++ instead of ++port)
  - check CPU and DSA ports before purging a VLAN
  - add Reviewed-by tags

Series applied, thanks Vivien.