[net-next PATCH v2 6/8] net: dsa: realtek: rtl8365mb: add port_bridge_{join,leave}

[Luiz Angelo Daros de Luca <luizluca@gmail.com>]

From: Alvin Šipraga <alsi@bang-olufsen.dk>

Implement hardware offloading of bridge functionality. This is achieved
by using the per-port isolation registers, which contain a forwarding
port mask. The switch will refuse to forward packets ingressed on a
given port to a port which is not in its forwarding mask.

For each bridge that is offloaded, use the DSA-provided bridge number
for the Extended Filtering ID (EFID). When using Independent VLAN
Learning (IVL), the forwarding database is keyed with the tuple
{VID, MAC, EFID}. There are 8 EFIDs available (0~7), but we reserve the
default EFID 0 for standalone ports where learning is disabled. This
fits nicely because DSA indexes the bridge number starting from 1.

Because of the limited number of EFIDs, we have to set the
max_num_bridges property of our switch to 7: we can't offload more than
that or we will fail to offer IVL as at least two bridges would end up
having to share an EFID.

Co-developed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
---
 drivers/net/dsa/realtek/realtek.h        |   5 ++
 drivers/net/dsa/realtek/rtl8365mb_main.c |  57 +++++++++++++++-
 drivers/net/dsa/realtek/rtl83xx.c        | 114 +++++++++++++++++++++++++++++++
 drivers/net/dsa/realtek/rtl83xx.h        |   7 ++
 4 files changed, 182 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/realtek/realtek.h b/drivers/net/dsa/realtek/realtek.h
index c03485a80d93..0942f534834d 100644
--- a/drivers/net/dsa/realtek/realtek.h
+++ b/drivers/net/dsa/realtek/realtek.h
@@ -107,6 +107,11 @@ struct realtek_ops {
 	int	(*enable_vlan)(struct realtek_priv *priv, bool enable);
 	int	(*enable_vlan4k)(struct realtek_priv *priv, bool enable);
 	int	(*enable_port)(struct realtek_priv *priv, int port, bool enable);
+	int	(*port_add_isolation)(struct realtek_priv *priv, int port,
+				      u32 mask);
+	int	(*port_remove_isolation)(struct realtek_priv *priv, int port,
+					 u32 mask);
+	int	(*port_set_efid)(struct realtek_priv *priv, int port, u32 efid);
 	int	(*phy_read)(struct realtek_priv *priv, int phy, int regnum);
 	int	(*phy_write)(struct realtek_priv *priv, int phy, int regnum,
 			     u16 val);
diff --git a/drivers/net/dsa/realtek/rtl8365mb_main.c b/drivers/net/dsa/realtek/rtl8365mb_main.c
index b37aa847a9aa..576bec52d863 100644
--- a/drivers/net/dsa/realtek/rtl8365mb_main.c
+++ b/drivers/net/dsa/realtek/rtl8365mb_main.c
@@ -285,6 +285,15 @@
 		(RTL8365MB_PORT_ISOLATION_REG_BASE + (_physport))
 #define   RTL8365MB_PORT_ISOLATION_MASK			0x07FF
 
+/* Extended filter ID registers - used to key forwarding database with IVL */
+#define RTL8365MB_EFID_MASK			GENMASK(2, 0)
+#define RTL8365MB_PORT_EFID_REG_BASE		0x0A32
+#define RTL8365MB_PORT_EFID_REG(_p) \
+		(RTL8365MB_PORT_EFID_REG_BASE + ((_p) >> 2))
+#define   RTL8365MB_PORT_EFID_OFFSET(_p)	(((_p) & 0x3) << 2)
+#define   RTL8365MB_PORT_EFID_MASK(_p) \
+		(RTL8365MB_EFID_MASK << RTL8365MB_PORT_EFID_OFFSET(_p))
+
 /* MSTP port state registers - indexed by tree instance */
 #define RTL8365MB_MSTI_CTRL_BASE			0x0A00
 #define RTL8365MB_MSTI_CTRL_REG(_msti, _physport) \
@@ -1439,10 +1448,44 @@ static int rtl8365mb_port_set_learning(struct realtek_priv *priv, int port,
 			    enable ? RTL8365MB_LEARN_LIMIT_MAX : 0);
 }
 
+static int rtl8365mb_port_set_efid(struct realtek_priv *priv, int port,
+				   u32 efid)
+{
+	return regmap_update_bits(priv->map, RTL8365MB_PORT_EFID_REG(port),
+				  RTL8365MB_PORT_EFID_MASK(port),
+				  efid << RTL8365MB_PORT_EFID_OFFSET(port));
+}
+
+/* Port isolation manipulation functions.
+ *
+ * The port isolation register controls the forwarding mask of a given
+ * port. The switch will not forward packets ingressed on a given port
+ * to ports which are not enabled in its forwarding mask.
+ *
+ * The port forwarding mask has the highest priority in forwarding
+ * decisions. The only exception to this rule is when the switch
+ * receives a packet on its CPU port with ALLOW=0. In that case the TX
+ * field of the CPU tag will override the forwarding port mask.
+ */
 static int rtl8365mb_port_set_isolation(struct realtek_priv *priv, int port,
 					u32 mask)
 {
-	return regmap_write(priv->map, RTL8365MB_PORT_ISOLATION_REG(port), mask);
+	return regmap_write(priv->map, RTL8365MB_PORT_ISOLATION_REG(port),
+			    mask);
+}
+
+static int rtl8365mb_port_add_isolation(struct realtek_priv *priv, int port,
+					u32 mask)
+{
+	return regmap_update_bits(priv->map, RTL8365MB_PORT_ISOLATION_REG(port),
+				  mask, mask);
+}
+
+static int rtl8365mb_port_remove_isolation(struct realtek_priv *priv, int port,
+					   u32 mask)
+{
+	return regmap_update_bits(priv->map, RTL8365MB_PORT_ISOLATION_REG(port),
+				  mask, 0);
 }
 
 static int rtl8365mb_mib_counter_read(struct realtek_priv *priv, int port,
@@ -2223,6 +2266,11 @@ static int rtl8365mb_setup(struct dsa_switch *ds)
 		if (ret)
 			goto out_teardown_irq;
 
+		/* Set the default EFID 0 for standalone mode */
+		ret = rtl8365mb_port_set_efid(priv, dp->index, 0);
+		if (ret)
+			goto out_teardown_irq;
+
 		/* Disable learning */
 		ret = rtl8365mb_port_set_learning(priv, dp->index, false);
 		if (ret)
@@ -2266,6 +2314,8 @@ static int rtl8365mb_setup(struct dsa_switch *ds)
 	if (ret)
 		goto out_teardown_irq;
 
+	/* The EFID is 3 bits, but EFID 0 is reserved for standalone ports */
+	ds->max_num_bridges = FIELD_MAX(RTL8365MB_EFID_MASK);
 	ds->configure_vlan_while_not_filtering = true;
 
 	/* Set up VLAN */
@@ -2389,6 +2439,8 @@ static const struct dsa_switch_ops rtl8365mb_switch_ops = {
 	.setup = rtl8365mb_setup,
 	.teardown = rtl8365mb_teardown,
 	.phylink_get_caps = rtl8365mb_phylink_get_caps,
+	.port_bridge_join = rtl83xx_port_bridge_join,
+	.port_bridge_leave = rtl83xx_port_bridge_leave,
 	.port_stp_state_set = rtl8365mb_port_stp_state_set,
 	.port_vlan_add = rtl8365mb_port_vlan_add,
 	.port_vlan_del = rtl8365mb_port_vlan_del,
@@ -2408,6 +2460,9 @@ static const struct dsa_switch_ops rtl8365mb_switch_ops = {
 
 static const struct realtek_ops rtl8365mb_ops = {
 	.detect = rtl8365mb_detect,
+	.port_add_isolation = rtl8365mb_port_add_isolation,
+	.port_remove_isolation = rtl8365mb_port_remove_isolation,
+	.port_set_efid = rtl8365mb_port_set_efid,
 	.phy_read = rtl8365mb_phy_read,
 	.phy_write = rtl8365mb_phy_write,
 };
diff --git a/drivers/net/dsa/realtek/rtl83xx.c b/drivers/net/dsa/realtek/rtl83xx.c
index 2b9bd4462714..3ab91cd82743 100644
--- a/drivers/net/dsa/realtek/rtl83xx.c
+++ b/drivers/net/dsa/realtek/rtl83xx.c
@@ -325,6 +325,120 @@ void rtl83xx_reset_deassert(struct realtek_priv *priv)
 	gpiod_set_value(priv->reset, false);
 }
 
+/**
+ * rtl83xx_port_bridge_join() - join a port to a bridge
+ * @ds: DSA switch instance
+ * @port: port index
+ * @bridge: bridge being joined
+ * @tx_forward_offload: if the switch can offload TX forwarding
+ * @extack: netlink extended ack for reporting errors
+ *
+ * This function handles joining a port to a bridge. It updates the port
+ * isolation masks and EFID.
+ *
+ * Context: Can sleep.
+ * Return: 0 on success, negative value for failure.
+ */
+int rtl83xx_port_bridge_join(struct dsa_switch *ds, int port,
+			     struct dsa_bridge bridge,
+			     bool *tx_forward_offload,
+			     struct netlink_ext_ack *extack)
+{
+	struct realtek_priv *priv = ds->priv;
+	struct dsa_port *dp;
+	u32 mask = 0;
+	int ret;
+
+	if (!priv->ops->port_add_isolation)
+		return -EOPNOTSUPP;
+
+	dev_dbg(priv->dev, "bridge %d join port %d\n", bridge.num, port);
+
+	/* Add this port to the isolation group of every other port
+	 * offloading this bridge.
+	 */
+	dsa_switch_for_each_user_port(dp, ds) {
+		/* Handle this port after */
+		if (dp->index == port)
+			continue;
+
+		/* Skip ports that are not in this bridge */
+		if (!dsa_port_offloads_bridge(dp, &bridge))
+			continue;
+
+		ret = priv->ops->port_add_isolation(priv, dp->index, BIT(port));
+		if (ret)
+			return ret;
+
+		mask |= BIT(dp->index);
+	}
+
+	/* Add those ports to the isolation group of this port */
+	ret = priv->ops->port_add_isolation(priv, port, mask);
+	if (ret)
+		return ret;
+
+	/* Use the bridge number as the EFID for this port */
+	if (priv->ops->port_set_efid) {
+		ret = priv->ops->port_set_efid(priv, port, bridge.num);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(rtl83xx_port_bridge_join, "REALTEK_DSA");
+
+/**
+ * rtl83xx_port_bridge_leave() - leave a bridge
+ * @ds: DSA switch instance
+ * @port: port index
+ * @bridge: bridge being left
+ *
+ * This function handles removing a port from a bridge. It updates the port
+ * isolation masks and EFID.
+ *
+ * Context: Can sleep.
+ * Return: nothing
+ */
+void rtl83xx_port_bridge_leave(struct dsa_switch *ds, int port,
+			       struct dsa_bridge bridge)
+{
+	struct realtek_priv *priv = ds->priv;
+	struct dsa_port *dp;
+	u32 mask = 0;
+
+	if (!priv->ops->port_remove_isolation)
+		return;
+
+	dev_dbg(priv->dev, "bridge %d leave port %d\n", bridge.num, port);
+
+	/* Remove this port from the isolation group of every other
+	 * port offloading this bridge.
+	 */
+	dsa_switch_for_each_user_port(dp, ds) {
+		/* Handle this port after */
+		if (dp->index == port)
+			continue;
+
+		/* Skip ports that are not in this bridge */
+		if (!dsa_port_offloads_bridge(dp, &bridge))
+			continue;
+
+		priv->ops->port_remove_isolation(priv, dp->index, BIT(port));
+
+		mask |= BIT(dp->index);
+	}
+
+	/* Remove those ports from the isolation group of this port */
+	priv->ops->port_remove_isolation(priv, port, mask);
+
+	/* Revert to the default EFID 0 for standalone mode */
+	if (priv->ops->port_set_efid)
+		priv->ops->port_set_efid(priv, port, 0);
+}
+EXPORT_SYMBOL_NS_GPL(rtl83xx_port_bridge_leave, "REALTEK_DSA");
+
 MODULE_AUTHOR("Luiz Angelo Daros de Luca <luizluca@gmail.com>");
 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 MODULE_DESCRIPTION("Realtek DSA switches common module");
diff --git a/drivers/net/dsa/realtek/rtl83xx.h b/drivers/net/dsa/realtek/rtl83xx.h
index c8a0ff8fd75e..2481a1aaa226 100644
--- a/drivers/net/dsa/realtek/rtl83xx.h
+++ b/drivers/net/dsa/realtek/rtl83xx.h
@@ -21,4 +21,11 @@ void rtl83xx_remove(struct realtek_priv *priv);
 void rtl83xx_reset_assert(struct realtek_priv *priv);
 void rtl83xx_reset_deassert(struct realtek_priv *priv);
 
+int rtl83xx_port_bridge_join(struct dsa_switch *ds, int port,
+			     struct dsa_bridge bridge,
+			     bool *tx_forward_offload,
+			     struct netlink_ext_ack *extack);
+void rtl83xx_port_bridge_leave(struct dsa_switch *ds, int port,
+			       struct dsa_bridge bridge);
+
 #endif /* _RTL83XX_H */

-- 
2.53.0