[PATCH] kernel: backport mt7530 dsa bridge-vlan fixes
Thibaut VARÈNE
hacks at slashdirt.org
Tue Aug 9 05:59:47 PDT 2022
Backport patches:
0b69c54c74bc ("net: dsa: mt7530: enable assisted learning on CPU port")
6087175b7991 ("net: dsa: mt7530: use independent VLAN learning on VLAN-unaware bridges)
These patches fix outstanding issues with bridge-vlan setups. In
particular, prior to this change setups involving a bridge-vlan with
untagged ethernet ports would see wireless clients roaming to the AP
experience connection drops lasting 2-5mn as the stale FDB entries
persist.
See the discussion here:
http://lists.openwrt.org/pipermail/openwrt-devel/2022-August/039175.html
Signed-off-by: Thibaut VARÈNE <hacks at slashdirt.org>
---
CCing DENG Qingfang <dqfext at gmail.com> as the upstream author: I had to
massage the patch a little bit to apply to older 5.10 code base.
Note: this cherry-picks with no conflict into openwrt-22.03, and I have
also successfully tested this backport there: I would thus recommend this
be cherry-picked into 22.03.
---
...enable-assisted-learning-on-CPU-port.patch | 83 ++++++
...LAN-learning-on-VLAN-unaware-bridges.patch | 272 ++++++++++++++++++
2 files changed, 355 insertions(+)
create mode 100644 target/linux/generic/backport-5.10/797-v5.15-0001-net-dsa-mt7530-enable-assisted-learning-on-CPU-port.patch
create mode 100644 target/linux/generic/backport-5.10/797-v5.15-0002-net-dsa-mt7530-use-independent-VLAN-learning-on-VLAN-unaware-bridges.patch
diff --git a/target/linux/generic/backport-5.10/797-v5.15-0001-net-dsa-mt7530-enable-assisted-learning-on-CPU-port.patch b/target/linux/generic/backport-5.10/797-v5.15-0001-net-dsa-mt7530-enable-assisted-learning-on-CPU-port.patch
new file mode 100644
index 0000000000..a474527ca9
--- /dev/null
+++ b/target/linux/generic/backport-5.10/797-v5.15-0001-net-dsa-mt7530-enable-assisted-learning-on-CPU-port.patch
@@ -0,0 +1,83 @@
+From 0b69c54c74bcb60e834013ccaf596caf05156a8e Mon Sep 17 00:00:00 2001
+From: DENG Qingfang <dqfext at gmail.com>
+Date: Wed, 4 Aug 2021 00:04:01 +0800
+Subject: [PATCH] net: dsa: mt7530: enable assisted learning on CPU port
+
+Consider the following bridge configuration, where bond0 is not
+offloaded:
+
+ +-- br0 --+
+ / / | \
+ / / | \
+ / | | bond0
+ / | | / \
+ swp0 swp1 swp2 swp3 swp4
+ . . .
+ . . .
+ A B C
+
+Address learning is enabled on offloaded ports (swp0~2) and the CPU
+port, so when client A sends a packet to C, the following will happen:
+
+1. The switch learns that client A can be reached at swp0.
+2. The switch probably already knows that client C can be reached at the
+ CPU port, so it forwards the packet to the CPU.
+3. The bridge core knows client C can be reached at bond0, so it
+ forwards the packet back to the switch.
+4. The switch learns that client A can be reached at the CPU port.
+5. The switch forwards the packet to either swp3 or swp4, according to
+ the packet's tag.
+
+That makes client A's MAC address flap between swp0 and the CPU port. If
+client B sends a packet to A, it is possible that the packet is
+forwarded to the CPU. With offload_fwd_mark = 1, the bridge core won't
+forward it back to the switch, resulting in packet loss.
+
+As we have the assisted_learning_on_cpu_port in DSA core now, enable
+that and disable hardware learning on the CPU port.
+
+Signed-off-by: DENG Qingfang <dqfext at gmail.com>
+Reviewed-by: Vladimir Oltean <oltean at gmail.com>
+Signed-off-by: David S. Miller <davem at davemloft.net>
+---
+ drivers/net/dsa/mt7530.c | 14 ++++++++------
+ 1 file changed, 8 insertions(+), 6 deletions(-)
+
+--- a/drivers/net/dsa/mt7530.c
++++ b/drivers/net/dsa/mt7530.c
+@@ -2026,6 +2026,7 @@ mt7530_setup(struct dsa_switch *ds)
+ */
+ dn = dsa_to_port(ds, MT7530_CPU_PORT)->master->dev.of_node->parent;
+ ds->configure_vlan_while_not_filtering = true;
++ ds->assisted_learning_on_cpu_port = true;
+ ds->mtu_enforcement_ingress = true;
+
+ if (priv->id == ID_MT7530) {
+@@ -2096,6 +2097,9 @@ mt7530_setup(struct dsa_switch *ds)
+ mt7530_rmw(priv, MT7530_PCR_P(i), PCR_MATRIX_MASK,
+ PCR_MATRIX_CLR);
+
++ /* Disable learning by default on all ports */
++ mt7530_set(priv, MT7530_PSC_P(i), SA_DIS);
++
+ if (dsa_is_cpu_port(ds, i)) {
+ ret = mt753x_cpu_port_enable(ds, i);
+ if (ret)
+@@ -2257,6 +2261,9 @@ mt7531_setup(struct dsa_switch *ds)
+ mt7530_rmw(priv, MT7530_PCR_P(i), PCR_MATRIX_MASK,
+ PCR_MATRIX_CLR);
+
++ /* Disable learning by default on all ports */
++ mt7530_set(priv, MT7530_PSC_P(i), SA_DIS);
++
+ mt7530_set(priv, MT7531_DBG_CNT(i), MT7531_DIS_CLR);
+
+ if (dsa_is_cpu_port(ds, i)) {
+@@ -2272,6 +2279,7 @@ mt7531_setup(struct dsa_switch *ds)
+ }
+
+ ds->configure_vlan_while_not_filtering = true;
++ ds->assisted_learning_on_cpu_port = true;
+ ds->mtu_enforcement_ingress = true;
+
+ /* Flush the FDB table */
diff --git a/target/linux/generic/backport-5.10/797-v5.15-0002-net-dsa-mt7530-use-independent-VLAN-learning-on-VLAN-unaware-bridges.patch b/target/linux/generic/backport-5.10/797-v5.15-0002-net-dsa-mt7530-use-independent-VLAN-learning-on-VLAN-unaware-bridges.patch
new file mode 100644
index 0000000000..39480df756
--- /dev/null
+++ b/target/linux/generic/backport-5.10/797-v5.15-0002-net-dsa-mt7530-use-independent-VLAN-learning-on-VLAN-unaware-bridges.patch
@@ -0,0 +1,272 @@
+From 6087175b7991a90c29269be26506f905104d7f12 Mon Sep 17 00:00:00 2001
+From: DENG Qingfang <dqfext at gmail.com>
+Date: Wed, 4 Aug 2021 00:04:02 +0800
+Subject: [PATCH] net: dsa: mt7530: use independent VLAN learning on
+ VLAN-unaware bridges
+
+Consider the following bridge configuration, where bond0 is not
+offloaded:
+
+ +-- br0 --+
+ / / | \
+ / / | \
+ / | | bond0
+ / | | / \
+ swp0 swp1 swp2 swp3 swp4
+ . . .
+ . . .
+ A B C
+
+Ideally, when the switch receives a packet from swp3 or swp4, it should
+forward the packet to the CPU, according to the port matrix and unknown
+unicast flood settings.
+
+But packet loss will happen if the destination address is at one of the
+offloaded ports (swp0~2). For example, when client C sends a packet to
+A, the FDB lookup will indicate that it should be forwarded to swp0, but
+the port matrix of swp3 and swp4 is configured to only allow the CPU to
+be its destination, so it is dropped.
+
+However, this issue does not happen if the bridge is VLAN-aware. That is
+because VLAN-aware bridges use independent VLAN learning, i.e. use VID
+for FDB lookup, on offloaded ports. As swp3 and swp4 are not offloaded,
+shared VLAN learning with default filter ID of 0 is used instead. So the
+lookup for A with filter ID 0 never hits and the packet can be forwarded
+to the CPU.
+
+In the current code, only two combinations were used to toggle user
+ports' VLAN awareness: one is PCR.PORT_VLAN set to port matrix mode with
+PVC.VLAN_ATTR set to transparent port, the other is PCR.PORT_VLAN set to
+security mode with PVC.VLAN_ATTR set to user port.
+
+It turns out that only PVC.VLAN_ATTR contributes to VLAN awareness, and
+port matrix mode just skips the VLAN table lookup. The reference manual
+is somehow misleading when describing PORT_VLAN modes. It states that
+PORT_MEM (VLAN port member) is used for destination if the VLAN table
+lookup hits, but actually **PORT_MEM & PORT_MATRIX** (bitwise AND of
+VLAN port member and port matrix) is used instead, which means we can
+have two or more separate VLAN-aware bridges with the same PVID and
+traffic won't leak between them.
+
+Therefore, to solve this, enable independent VLAN learning with PVID 0
+on VLAN-unaware bridges, by setting their PCR.PORT_VLAN to fallback
+mode, while leaving standalone ports in port matrix mode. The CPU port
+is always set to fallback mode to serve those bridges.
+
+During testing, it is found that FDB lookup with filter ID of 0 will
+also hit entries with VID 0 even with independent VLAN learning. To
+avoid that, install all VLANs with filter ID of 1.
+
+Signed-off-by: DENG Qingfang <dqfext at gmail.com>
+Reviewed-by: Vladimir Oltean <olteanv at gmail.com>
+Signed-off-by: David S. Miller <davem at davemloft.net>
+---
+ drivers/net/dsa/mt7530.c | 71 +++++++++++++++++++++++++++++-----------
+ drivers/net/dsa/mt7530.h | 9 ++++-
+ 2 files changed, 59 insertions(+), 21 deletions(-)
+
+--- a/drivers/net/dsa/mt7530.c
++++ b/drivers/net/dsa/mt7530.c
+@@ -1019,6 +1019,10 @@ mt753x_cpu_port_enable(struct dsa_switch
+ mt7530_write(priv, MT7530_PCR_P(port),
+ PCR_MATRIX(dsa_user_ports(priv->ds)));
+
++ /* Set to fallback mode for independent VLAN learning */
++ mt7530_rmw(priv, MT7530_PCR_P(port), PCR_PORT_VLAN_MASK,
++ MT7530_PORT_FALLBACK_MODE);
++
+ return 0;
+ }
+
+@@ -1185,6 +1189,10 @@ mt7530_port_bridge_join(struct dsa_switc
+ PCR_MATRIX_MASK, PCR_MATRIX(port_bitmap));
+ priv->ports[port].pm |= PCR_MATRIX(port_bitmap);
+
++ /* Set to fallback mode for independent VLAN learning */
++ mt7530_rmw(priv, MT7530_PCR_P(port), PCR_PORT_VLAN_MASK,
++ MT7530_PORT_FALLBACK_MODE);
++
+ mutex_unlock(&priv->reg_mutex);
+
+ return 0;
+@@ -1197,16 +1205,21 @@ mt7530_port_set_vlan_unaware(struct dsa_
+ bool all_user_ports_removed = true;
+ int i;
+
+- /* When a port is removed from the bridge, the port would be set up
+- * back to the default as is at initial boot which is a VLAN-unaware
+- * port.
++ /* This is called after .port_bridge_leave when leaving a VLAN-aware
++ * bridge. Don't set standalone ports to fallback mode.
+ */
+- mt7530_rmw(priv, MT7530_PCR_P(port), PCR_PORT_VLAN_MASK,
+- MT7530_PORT_MATRIX_MODE);
++ if (dsa_to_port(ds, port)->bridge_dev)
++ mt7530_rmw(priv, MT7530_PCR_P(port), PCR_PORT_VLAN_MASK,
++ MT7530_PORT_FALLBACK_MODE);
++
+ mt7530_rmw(priv, MT7530_PVC_P(port), VLAN_ATTR_MASK | PVC_EG_TAG_MASK,
+ VLAN_ATTR(MT7530_VLAN_TRANSPARENT) |
+ PVC_EG_TAG(MT7530_VLAN_EG_CONSISTENT));
+
++ /* Set PVID to 0 */
++ mt7530_rmw(priv, MT7530_PPBV1_P(port), G0_PORT_VID_MASK,
++ G0_PORT_VID_DEF);
++
+ for (i = 0; i < MT7530_NUM_PORTS; i++) {
+ if (dsa_is_user_port(ds, i) &&
+ dsa_port_is_vlan_filtering(dsa_to_port(ds, i))) {
+@@ -1232,15 +1245,14 @@ mt7530_port_set_vlan_aware(struct dsa_sw
+ struct mt7530_priv *priv = ds->priv;
+
+ /* Trapped into security mode allows packet forwarding through VLAN
+- * table lookup. CPU port is set to fallback mode to let untagged
+- * frames pass through.
++ * table lookup.
+ */
+- if (dsa_is_cpu_port(ds, port))
+- mt7530_rmw(priv, MT7530_PCR_P(port), PCR_PORT_VLAN_MASK,
+- MT7530_PORT_FALLBACK_MODE);
+- else
++ if (dsa_is_user_port(ds, port)) {
+ mt7530_rmw(priv, MT7530_PCR_P(port), PCR_PORT_VLAN_MASK,
+ MT7530_PORT_SECURITY_MODE);
++ mt7530_rmw(priv, MT7530_PPBV1_P(port), G0_PORT_VID_MASK,
++ G0_PORT_VID(priv->ports[port].pvid));
++ }
+
+ /* Set the port as a user port which is to be able to recognize VID
+ * from incoming packets before fetching entry within the VLAN table.
+@@ -1282,6 +1294,13 @@ mt7530_port_bridge_leave(struct dsa_swit
+ PCR_MATRIX(BIT(MT7530_CPU_PORT)));
+ priv->ports[port].pm = PCR_MATRIX(BIT(MT7530_CPU_PORT));
+
++ /* When a port is removed from the bridge, the port would be set up
++ * back to the default as is at initial boot which is a VLAN-unaware
++ * port.
++ */
++ mt7530_rmw(priv, MT7530_PCR_P(port), PCR_PORT_VLAN_MASK,
++ MT7530_PORT_MATRIX_MODE);
++
+ mutex_unlock(&priv->reg_mutex);
+ }
+
+@@ -1481,7 +1500,8 @@ mt7530_hw_vlan_add(struct mt7530_priv *p
+ /* Validate the entry with independent learning, create egress tag per
+ * VLAN and joining the port as one of the port members.
+ */
+- val = IVL_MAC | VTAG_EN | PORT_MEM(new_members) | VLAN_VALID;
++ val = IVL_MAC | VTAG_EN | PORT_MEM(new_members) | FID(FID_BRIDGED) |
++ VLAN_VALID;
+ mt7530_write(priv, MT7530_VAWD1, val);
+
+ /* Decide whether adding tag or not for those outgoing packets from the
+@@ -1574,9 +1594,13 @@ mt7530_port_vlan_add(struct dsa_switch *
+ }
+
+ if (pvid) {
+- mt7530_rmw(priv, MT7530_PPBV1_P(port), G0_PORT_VID_MASK,
+- G0_PORT_VID(vlan->vid_end));
+ priv->ports[port].pvid = vlan->vid_end;
++
++ /* Only configure PVID if VLAN filtering is enabled */
++ if (dsa_port_is_vlan_filtering(dsa_to_port(ds, port)))
++ mt7530_rmw(priv, MT7530_PPBV1_P(port),
++ G0_PORT_VID_MASK,
++ G0_PORT_VID(vlan->vid_end));
+ }
+
+ mutex_unlock(&priv->reg_mutex);
+@@ -1588,11 +1612,10 @@ mt7530_port_vlan_del(struct dsa_switch *
+ {
+ struct mt7530_hw_vlan_entry target_entry;
+ struct mt7530_priv *priv = ds->priv;
+- u16 vid, pvid;
++ u16 vid;
+
+ mutex_lock(&priv->reg_mutex);
+
+- pvid = priv->ports[port].pvid;
+ for (vid = vlan->vid_begin; vid <= vlan->vid_end; ++vid) {
+ mt7530_hw_vlan_entry_init(&target_entry, port, 0);
+ mt7530_hw_vlan_update(priv, vid, &target_entry,
+@@ -1601,12 +1624,13 @@ mt7530_port_vlan_del(struct dsa_switch *
+ /* PVID is being restored to the default whenever the PVID port
+ * is being removed from the VLAN.
+ */
+- if (pvid == vid)
+- pvid = G0_PORT_VID_DEF;
++ if (priv->ports[port].pvid == vlan->vid_end) {
++ priv->ports[port].pvid = G0_PORT_VID_DEF;
++ mt7530_rmw(priv, MT7530_PPBV1_P(port), G0_PORT_VID_MASK,
++ G0_PORT_VID_DEF);
++ }
+ }
+
+- mt7530_rmw(priv, MT7530_PPBV1_P(port), G0_PORT_VID_MASK, pvid);
+- priv->ports[port].pvid = pvid;
+
+ mutex_unlock(&priv->reg_mutex);
+
+@@ -2104,9 +2128,14 @@ mt7530_setup(struct dsa_switch *ds)
+ ret = mt753x_cpu_port_enable(ds, i);
+ if (ret)
+ return ret;
+- } else
++ } else {
+ mt7530_port_disable(ds, i);
+
++ /* Set default PVID to 0 on all user ports */
++ mt7530_rmw(priv, MT7530_PPBV1_P(i), G0_PORT_VID_MASK,
++ G0_PORT_VID_DEF);
++ }
++
+ /* Enable consistent egress tag */
+ mt7530_rmw(priv, MT7530_PVC_P(i), PVC_EG_TAG_MASK,
+ PVC_EG_TAG(MT7530_VLAN_EG_CONSISTENT));
+@@ -2270,9 +2299,14 @@ mt7531_setup(struct dsa_switch *ds)
+ ret = mt753x_cpu_port_enable(ds, i);
+ if (ret)
+ return ret;
+- } else
++ } else {
+ mt7530_port_disable(ds, i);
+
++ /* Set default PVID to 0 on all user ports */
++ mt7530_rmw(priv, MT7530_PPBV1_P(i), G0_PORT_VID_MASK,
++ G0_PORT_VID_DEF);
++ }
++
+ /* Enable consistent egress tag */
+ mt7530_rmw(priv, MT7530_PVC_P(i), PVC_EG_TAG_MASK,
+ PVC_EG_TAG(MT7530_VLAN_EG_CONSISTENT));
+--- a/drivers/net/dsa/mt7530.h
++++ b/drivers/net/dsa/mt7530.h
+@@ -146,11 +146,18 @@ enum mt7530_vlan_cmd {
+ #define VTAG_EN BIT(28)
+ /* VLAN Member Control */
+ #define PORT_MEM(x) (((x) & 0xff) << 16)
++/* Filter ID */
++#define FID(x) (((x) & 0x7) << 1)
+ /* VLAN Entry Valid */
+ #define VLAN_VALID BIT(0)
+ #define PORT_MEM_SHFT 16
+ #define PORT_MEM_MASK 0xff
+
++enum mt7530_fid {
++ FID_STANDALONE = 0,
++ FID_BRIDGED = 1,
++};
++
+ #define MT7530_VAWD2 0x98
+ /* Egress Tag Control */
+ #define ETAG_CTRL_P(p, x) (((x) & 0x3) << ((p) << 1))
+@@ -245,7 +252,7 @@ enum mt7530_vlan_port_attr {
+ #define MT7530_PPBV1_P(x) (0x2014 + ((x) * 0x100))
+ #define G0_PORT_VID(x) (((x) & 0xfff) << 0)
+ #define G0_PORT_VID_MASK G0_PORT_VID(0xfff)
+-#define G0_PORT_VID_DEF G0_PORT_VID(1)
++#define G0_PORT_VID_DEF G0_PORT_VID(0)
+
+ /* Register for port MAC control register */
+ #define MT7530_PMCR_P(x) (0x3000 + ((x) * 0x100))
--
2.30.2
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