On 9/8/2020 3:28 PM, Florian Fainelli wrote:


On 9/7/2020 9:07 PM, Florian Fainelli wrote:


On 9/7/2020 11:29 AM, Vladimir Oltean wrote:
From: Vladimir Oltean <vladimir.olt...@nxp.com>

As explained in commit 54a0ed0df496 ("net: dsa: provide an option for
drivers to always receive bridge VLANs"), DSA has historically been
skipping VLAN switchdev operations when the bridge wasn't in
vlan_filtering mode, but the reason why it was doing that has never been
clear. So the configure_vlan_while_not_filtering option is there merely
to preserve functionality for existing drivers. It isn't some behavior
that drivers should opt into. Ideally, when all drivers leave this flag
set, we can delete the dsa_port_skip_vlan_configuration() function.

New drivers always seem to omit setting this flag, for some reason. So
let's reverse the logic: the DSA core sets it by default to true before
the .setup() callback, and legacy drivers can turn it off. This way, new
drivers get the new behavior by default, unless they explicitly set the
flag to false, which is more obvious during review.

Remove the assignment from drivers which were setting it to true, and
add the assignment to false for the drivers that didn't previously have
it. This way, it should be easier to see how many we have left.

The following drivers: lan9303, mv88e6060 were skipped from setting this
flag to false, because they didn't have any VLAN offload ops in the
first place.

Also, print a message to the console every time a VLAN has been skipped.
This is mildly annoying on purpose, so that (a) it is at least clear
that VLANs are being skipped - the legacy behavior in itself is
confusing - and (b) people have one more incentive to convert to the new
behavior.

No behavior change except for the added prints is intended at this time.

Signed-off-by: Vladimir Oltean <vladimir.olt...@nxp.com>

You should be able to make b53 and bcm_sf2 also use configure_vlan_while_not_filtering to true (or rather not specify it), give me until tomorrow to run various tests if you don't mind.

For a reason I do not understand, we should be able to set configure_vlan_while_not_filtering to true, and get things to work, however this does not work for bridged ports unless the bridge also happens to have VLAN filtering enabled. There is a valid VLAN entry configured for the desired port, but nothing ingress or egresses, I will keep debugging but you can send this patch as-is I believe and I will amend b53 later once I understand what is going on.

Found the problem, we do not allow the CPU port to be configured as untagged, and when we toggle vlan_filtering we actually incorrectly "move" the PVID from 1 to 0, which is incorrect, but since the CPU is also untagged in VID 0 this is why it "works" or rather two mistakes canceling it each other.

I still need to confirm this, but the bridge in VLAN filtering mode seems to support receiving frames with the default_pvid as tagged, and it will untag it for the bridge master device transparently.

The reason for not allowing the CPU port to be untagged (ca8931948344c485569b04821d1f6bcebccd376b) was because the CPU port could be added as untagged in several VLANs, e.g.: when port0-3 are PVID 1 untagged, and port 4 is PVID 2 untagged. Back then there was no support for Broadcom tags, so the only way to differentiate traffic properly was to also add a pair of tagged VIDs to the DSA master.

I am still trying to remember whether there were other concerns that prompted me to make that change and would appreciate some thoughts on that. Tangentially, maybe we should finally add support for programming the CPU port's VLAN membership independently from the other ports.

The following appears to work nicely now and allows us to get rid of the b53_vlan_filtering() logic, which would no longer work now because it assumed that toggling vlan_filtering implied that there would be no VLAN configuration when filtering was off.

diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index 26fcff85d881..fac033730f4a 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -1322,23 +1322,6 @@ EXPORT_SYMBOL(b53_phylink_mac_link_up);
int b53_vlan_filtering(struct dsa_switch *ds, int port, bool vlan_filtering)
 {
        struct b53_device *dev = ds->priv;
-       u16 pvid, new_pvid;
-
-       b53_read16(dev, B53_VLAN_PAGE, B53_VLAN_PORT_DEF_TAG(port), &pvid);
-       if (!vlan_filtering) {
- /* Filtering is currently enabled, use the default PVID since
-                * the bridge does not expect tagging anymore
-                */
-               dev->ports[port].pvid = pvid;
-               new_pvid = b53_default_pvid(dev);
-       } else {
- /* Filtering is currently disabled, restore the previous PVID */
-               new_pvid = dev->ports[port].pvid;
-       }
-
-       if (pvid != new_pvid)
-               b53_write16(dev, B53_VLAN_PAGE, B53_VLAN_PORT_DEF_TAG(port),
-                           new_pvid);

        b53_enable_vlan(dev, dev->vlan_enabled, vlan_filtering);

@@ -1389,7 +1372,7 @@ void b53_vlan_add(struct dsa_switch *ds, int port,
                        untagged = true;

                vl->members |= BIT(port);
-               if (untagged && !dsa_is_cpu_port(ds, port))
+               if (untagged)
                        vl->untag |= BIT(port);
                else
                        vl->untag &= ~BIT(port);
@@ -1427,7 +1410,7 @@ int b53_vlan_del(struct dsa_switch *ds, int port,
                if (pvid == vid)
                        pvid = b53_default_pvid(dev);

-               if (untagged && !dsa_is_cpu_port(ds, port))
+               if (untagged)
                        vl->untag &= ~(BIT(port));

                b53_set_vlan_entry(dev, vid, vl);
@@ -2563,6 +2546,8 @@ struct b53_device *b53_switch_alloc(struct device *base,
        dev->priv = priv;
        dev->ops = ops;
        ds->ops = &b53_switch_ops;
+       ds->configure_vlan_while_not_filtering = true;
+       dev->vlan_enabled = ds->configure_vlan_while_not_filtering;
        mutex_init(&dev->reg_mutex);
        mutex_init(&dev->stats_mutex);


--
Florian

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