[PATCH RFC net-next 04/10] net: dsa: mv88e6xxx: Add all hosts mc addr to ATU

[Joseph Huang <Joseph.Huang@garmin.com>]

Add local network all hosts multicast address (224.0.0.1) and link-local
all nodes multicast address (ff02::1) to the ATU so that IGMP/MLD
Queries can be forwarded even when multicast flooding is disabled on a
port.

Signed-off-by: Joseph Huang <Joseph.Huang@garmin.com>
---
 drivers/net/dsa/mv88e6xxx/Kconfig | 12 ++++++++
 drivers/net/dsa/mv88e6xxx/chip.c  | 47 +++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/Kconfig b/drivers/net/dsa/mv88e6xxx/Kconfig
index e3181d5471df..ef7798bf50d7 100644
--- a/drivers/net/dsa/mv88e6xxx/Kconfig
+++ b/drivers/net/dsa/mv88e6xxx/Kconfig
@@ -17,3 +17,15 @@ config NET_DSA_MV88E6XXX_PTP
 	help
 	  Say Y to enable PTP hardware timestamping on Marvell 88E6xxx switch
 	  chips that support it.
+
+config NET_DSA_MV88E6XXX_ALWAYS_FLOOD_LOCAL_ALL_HOSTS_ADDRESS
+	bool "Always flood local all hosts multicast packets"
+	depends on NET_DSA_MV88E6XXX
+	help
+	  When set to Y, always flood multicast packets destined for
+	  224.0.0.1 (Local Network All Hosts multicast address) and
+	  ff02::1 (Link-Local All Nodes multicast address), even when
+	  multicast flooding is disabled for a port.  This is so that
+	  multicast snooping can continue to function even when
+	  multicast flooding is disabled.
+	  If in doubt, say N.
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 9ed1821184ec..fddcb596c421 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2488,6 +2488,41 @@ static int mv88e6xxx_broadcast_setup(struct mv88e6xxx_chip *chip, u16 vid)
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_NET_DSA_MV88E6XXX_ALWAYS_FLOOD_LOCAL_ALL_HOSTS_ADDRESS)
+static int mv88e6xxx_port_add_multicast(struct mv88e6xxx_chip *chip, int port,
+					u16 vid)
+{
+	u8 state = MV88E6XXX_G1_ATU_DATA_STATE_MC_STATIC;
+	const char multicast[][ETH_ALEN] = {
+		{ 0x01, 0x00, 0x5e, 0x00, 0x00, 0x01 },
+		{ 0x33, 0x33, 0x00, 0x00, 0x00, 0x01 }
+	};
+	int i, err;
+
+	for (i = 0; i < ARRAY_SIZE(multicast); i++) {
+		err = mv88e6xxx_port_db_load_purge(chip, port, multicast[i], vid, state);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int mv88e6xxx_multicast_setup(struct mv88e6xxx_chip *chip, u16 vid)
+{
+	int port;
+	int err;
+
+	for (port = 0; port < mv88e6xxx_num_ports(chip); port++) {
+		err = mv88e6xxx_port_add_multicast(chip, port, vid);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+#endif
+
 struct mv88e6xxx_port_broadcast_sync_ctx {
 	int port;
 	bool flood;
@@ -2572,6 +2607,12 @@ static int mv88e6xxx_port_vlan_join(struct mv88e6xxx_chip *chip, int port,
 		err = mv88e6xxx_broadcast_setup(chip, vlan.vid);
 		if (err)
 			return err;
+
+#if IS_ENABLED(CONFIG_NET_DSA_MV88E6XXX_ALWAYS_FLOOD_LOCAL_ALL_HOSTS_ADDRESS)
+		err = mv88e6xxx_multicast_setup(chip, vlan.vid);
+		if (err)
+			return err;
+#endif
 	} else if (vlan.member[port] != member) {
 		vlan.member[port] = member;
 
@@ -3930,6 +3971,12 @@ static int mv88e6xxx_setup(struct dsa_switch *ds)
 	if (err)
 		goto unlock;
 
+#if IS_ENABLED(CONFIG_NET_DSA_MV88E6XXX_ALWAYS_FLOOD_LOCAL_ALL_HOSTS_ADDRESS)
+	err = mv88e6xxx_multicast_setup(chip, 0);
+	if (err)
+		goto unlock;
+#endif
+
 	err = mv88e6xxx_pot_setup(chip);
 	if (err)
 		goto unlock;
-- 
2.17.1