On Fri, Mar 04, 2022 at 00:20, Vladimir Oltean [off-list ref] wrote:

On Tue, Mar 01, 2022 at 11:03:18AM +0100, Tobias Waldekranz wrote:

quoted

Add the usual trampoline functionality from the generic DSA layer down
to the drivers for MST state changes.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
 include/net/dsa.h  |  2 ++
 net/dsa/dsa_priv.h |  2 ++
 net/dsa/port.c     | 30 ++++++++++++++++++++++++++++++
 net/dsa/slave.c    |  6 ++++++
 4 files changed, 40 insertions(+)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index cc8acb01bd9b..096e6e3a8e1e 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h

@@ -943,6 +943,8 @@ struct dsa_switch_ops {
 				     struct dsa_bridge bridge);
 	void	(*port_stp_state_set)(struct dsa_switch *ds, int port,
 				      u8 state);
+	int	(*port_mst_state_set)(struct dsa_switch *ds, int port,
+				      const struct switchdev_mst_state *state);
 	void	(*port_fast_age)(struct dsa_switch *ds, int port);
 	int	(*port_pre_bridge_flags)(struct dsa_switch *ds, int port,
 					 struct switchdev_brport_flags flags,

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 87ec0697e92e..a620e079ebc5 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h

@@ -198,6 +198,8 @@ static inline struct net_device *dsa_master_find_slave(struct net_device *dev,
 void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp,
 			       const struct dsa_device_ops *tag_ops);
 int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age);
+int dsa_port_set_mst_state(struct dsa_port *dp,
+			   const struct switchdev_mst_state *state);
 int dsa_port_enable_rt(struct dsa_port *dp, struct phy_device *phy);
 int dsa_port_enable(struct dsa_port *dp, struct phy_device *phy);
 void dsa_port_disable_rt(struct dsa_port *dp);

diff --git a/net/dsa/port.c b/net/dsa/port.c
index 5f45cb7d70ba..26cfbc8ab499 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c

@@ -108,6 +108,36 @@ int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age)
 	return 0;
 }
 
+int dsa_port_set_mst_state(struct dsa_port *dp,
+			   const struct switchdev_mst_state *state)
+{
+	struct dsa_switch *ds = dp->ds;
+	int err, port = dp->index;
+
+	if (!ds->ops->port_mst_state_set)
+		return -EOPNOTSUPP;
+
+	err = ds->ops->port_mst_state_set(ds, port, state);
+	if (err)
+		return err;
+
+	if (!dsa_port_can_configure_learning(dp) || dp->learning) {
+		switch (state->state) {
+		case BR_STATE_DISABLED:
+		case BR_STATE_BLOCKING:
+		case BR_STATE_LISTENING:
+			/* Ideally we would only fast age entries
+			 * belonging to VLANs controlled by this
+			 * MST.
+			 */
+			dsa_port_fast_age(dp);

Does mv88e6xxx support this? If it does, you might just as well
introduce another variant of ds->ops->port_fast_age() for an msti.

You can limit ATU operations to a particular FID. So the way I see it we
could either have:

int (*port_vlan_fast_age)(struct dsa_switch *ds, int port, u16 vid)

+ Maybe more generic. You could imagine there being a way to trigger
  this operation from userspace for example.
- We would have to keep the VLAN<->MSTI mapping in the DSA layer in
  order to be able to do the fan-out in dsa_port_set_mst_state.

or:

int (*port_msti_fast_age)(struct dsa_switch *ds, int port, u16 msti)

+ Let's the mapping be an internal affair in the driver.
- Perhaps, less generically useful.

Which one do you prefer? Or is there a hidden third option? :)

And since it is new code, you could require that drivers _do_ support
configuring learning before they could support MSTP. After all, we don't
want to keep legacy mechanisms in place forever.

By "configuring learning", do you mean this new fast-age-per-vid/msti,
or being able to enable/disable learning per port? If it's the latter,
I'm not sure I understand how those two are related.