[PATCH net-next v4 5/9] net: dsa: lan9645x: add bridge support

Jens Emil Schulz Østergaard
2026-04-30T09:34:59Z

Add support for hardware offloading of the bridge. We support a single
bridge device.

Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Signed-off-by: Jens Emil Schulz Østergaard <jensemil.schulzostergaard@microchip.com>
---
Changes in v4:
- set_host_flood changed to per port work to coalesce values and skip
atomic allocations

Changes in v3:
- allow disabling aging with explicit zero parameters.
- fix non-forwarding stp states
- fix restore host_flood requests on bridge leave

Changes in v2:
- variable name consistency
- port_set_learning use stp_state before writing to hw
- add set_host_flood for selftests, which need promic/all_multi on
standalone interfaces
---
drivers/net/dsa/microchip/lan9645x/lan9645x_main.c | 285 +++++++++++++++++++++
drivers/net/dsa/microchip/lan9645x/lan9645x_main.h | 22 ++
2 files changed, 307 insertions(+)

diff --git a/drivers/net/dsa/microchip/lan9645x/lan9645x_main.c b/drivers/net/dsa/microchip/lan9645x/lan9645x_main.c
index 6fd66ea67cfd..70f6a11f0753 100644
--- a/drivers/net/dsa/microchip/lan9645x/lan9645x_main.c
+++ b/drivers/net/dsa/microchip/lan9645x/lan9645x_main.c
@@ -67,7 +67,9 @@ static void lan9645x_teardown(struct dsa_switch *ds)
{
struct lan9645x *lan9645x = ds->priv;

+ destroy_workqueue(lan9645x->owq);
lan9645x_npi_port_deinit(lan9645x, lan9645x->npi);
+ mutex_destroy(&lan9645x->fwd_domain_lock);
}

static int lan9645x_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
@@ -133,6 +135,8 @@ static int lan9645x_setup(struct dsa_switch *ds)
return err;
}

+ mutex_init(&lan9645x->fwd_domain_lock);
+
/* Link Aggregation Mode: NETDEV_LAG_HASH_L2 */
lan_wr(ANA_AGGR_CFG_AC_SMAC_ENA |
ANA_AGGR_CFG_AC_DMAC_ENA,
@@ -239,6 +243,11 @@ static int lan9645x_setup(struct dsa_switch *ds)

lan9645x_port_set_tail_drop_wm(lan9645x);

+ lan9645x->owq = alloc_ordered_workqueue("%s-owq", 0,
+ dev_name(lan9645x->dev));
+ if (!lan9645x->owq)
+ return -ENOMEM;
+
ds->mtu_enforcement_ingress = true;
ds->assisted_learning_on_cpu_port = true;
ds->fdb_isolation = true;
@@ -257,6 +266,272 @@ static void lan9645x_port_phylink_get_caps(struct dsa_switch *ds, int port,
lan9645x_phylink_get_caps(ds->priv, port, config);
}

+static int lan9645x_set_ageing_time(struct dsa_switch *ds, unsigned int msecs)
+{
+ u32 age_secs = max(1, msecs / MSEC_PER_SEC / 2);
+ struct lan9645x *lan9645x = ds->priv;
+
+ /* Entry is must suffer two aging scans before it is removed, so it is
+ * aged after 2*AGE_PERIOD, and the unit is in seconds.
+ * An age period of 0 disables automatic aging.
+ */
+ lan_rmw(ANA_AUTOAGE_AGE_PERIOD_SET(msecs ? age_secs : 0),
+ ANA_AUTOAGE_AGE_PERIOD,
+ lan9645x, ANA_AUTOAGE);
+ return 0;
+}
+
+static int lan9645x_port_pre_bridge_flags(struct dsa_switch *ds, int port,
+ struct switchdev_brport_flags flags,
+ struct netlink_ext_ack *extack)
+{
+ if (flags.mask &
+ ~(BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD | BR_BCAST_FLOOD))
+ return -EINVAL;
+
+ return 0;
+}
+
+static void lan9645x_port_pgid_set(struct lan9645x *lan9645x, u16 pgid,
+ int chip_port, bool enabled)
+{
+ u32 reg_msk, port_msk;
+
+ WARN_ON(chip_port > CPU_PORT);
+
+ port_msk = ANA_PGID_PGID_SET(enabled ? BIT(chip_port) : 0);
+ reg_msk = ANA_PGID_PGID_SET(BIT(chip_port));
+
+ lan_rmw(port_msk, reg_msk, lan9645x, ANA_PGID(pgid));
+}
+
+static void lan9645x_port_set_learning(struct lan9645x *lan9645x, int port,
+ bool enabled)
+{
+ struct lan9645x_port *p = lan9645x_to_port(lan9645x, port);
+
+ p->learn_ena = enabled;
+
+ enabled = enabled && (p->stp_state == BR_STATE_LEARNING ||
+ p->stp_state == BR_STATE_FORWARDING);
+
+ lan_rmw(ANA_PORT_CFG_LEARN_ENA_SET(enabled), ANA_PORT_CFG_LEARN_ENA,
+ lan9645x, ANA_PORT_CFG(port));
+}
+
+static int lan9645x_port_bridge_flags(struct dsa_switch *ds, int port,
+ struct switchdev_brport_flags f,
+ struct netlink_ext_ack *extack)
+{
+ struct lan9645x *lan9645x = ds->priv;
+
+ if (WARN_ON(port == lan9645x->npi))
+ return -EINVAL;
+
+ if (f.mask & BR_LEARNING)
+ lan9645x_port_set_learning(lan9645x, port,
+ !!(f.val & BR_LEARNING));
+
+ if (f.mask & BR_FLOOD)
+ lan9645x_port_pgid_set(lan9645x, PGID_UC, port,
+ !!(f.val & BR_FLOOD));
+
+ if (f.mask & BR_MCAST_FLOOD) {
+ bool ena = !!(f.val & BR_MCAST_FLOOD);
+
+ lan9645x_port_pgid_set(lan9645x, PGID_MC, port, ena);
+ lan9645x_port_pgid_set(lan9645x, PGID_MCIPV4, port, ena);
+ lan9645x_port_pgid_set(lan9645x, PGID_MCIPV6, port, ena);
+ }
+
+ if (f.mask & BR_BCAST_FLOOD)
+ lan9645x_port_pgid_set(lan9645x, PGID_BC, port,
+ !!(f.val & BR_BCAST_FLOOD));
+
+ return 0;
+}
+
+static void lan9645x_update_fwd_mask(struct lan9645x *lan9645x)
+{
+ struct lan9645x_port *p;
+ struct dsa_port *dp;
+
+ lockdep_assert_held(&lan9645x->fwd_domain_lock);
+
+ /* Updates the source port PGIDs, making sure frames from p
+ * are only forwarded to ports q != p, where q is relevant to forward
+ */
+ dsa_switch_for_each_available_port(dp, lan9645x->ds) {
+ u32 mask = 0;
+
+ p = lan9645x_to_port(lan9645x, dp->index);
+
+ if (lan9645x_port_is_bridged(p) &&
+ (lan9645x->bridge_fwd_mask & BIT(dp->index))) {
+ mask = lan9645x->bridge_mask &
+ lan9645x->bridge_fwd_mask & ~BIT(dp->index);
+ }
+
+ lan_wr(mask, lan9645x, ANA_PGID(PGID_SRC + dp->index));
+ }
+}
+
+static void __lan9645x_port_mark_host_flood(struct lan9645x *lan9645x, int port,
+ bool uc, bool mc)
+{
+ lockdep_assert_held(&lan9645x->fwd_domain_lock);
+
+ if (uc)
+ lan9645x->host_flood_uc_mask |= BIT(port);
+ else
+ lan9645x->host_flood_uc_mask &= ~BIT(port);
+
+ if (mc)
+ lan9645x->host_flood_mc_mask |= BIT(port);
+ else
+ lan9645x->host_flood_mc_mask &= ~BIT(port);
+}
+
+static void __lan9645x_port_set_host_flood(struct lan9645x *lan9645x)
+{
+ bool mc_ena, uc_ena;
+ u16 unbridged;
+
+ lockdep_assert_held(&lan9645x->fwd_domain_lock);
+
+ /* We want promiscuous and all_multi to affect standalone ports, for
+ * debug and test purposes.
+ *
+ * However, the linux bridge is incredibly eager to put bridged ports in
+ * promiscuous mode.
+
+ * This is unfortunate since lan9645x flood masks are global and not per
+ * ingress port. When some port triggers unknown uc/mc to the CPU, the
+ * traffic from any port is forwarded to the CPU.
+ *
+ * If the host CPU is weak, this can cause tremendous stress. Therefore,
+ * we compromise by ignoring this host flood request for bridged ports.
+ */
+ unbridged = ~lan9645x->bridge_mask & GENMASK(NUM_PHYS_PORTS - 1, 0);
+
+ uc_ena = !!(lan9645x->host_flood_uc_mask & unbridged);
+ lan9645x_port_pgid_set(lan9645x, PGID_UC, CPU_PORT, uc_ena);
+
+ mc_ena = !!(lan9645x->host_flood_mc_mask & unbridged);
+ lan9645x_port_pgid_set(lan9645x, PGID_MC, CPU_PORT, mc_ena);
+ lan9645x_port_pgid_set(lan9645x, PGID_MCIPV4, CPU_PORT, mc_ena);
+ lan9645x_port_pgid_set(lan9645x, PGID_MCIPV6, CPU_PORT, mc_ena);
+}
+
+static void lan9645x_host_flood_work_fn(struct work_struct *work)
+{
+ struct lan9645x_port *p = container_of(work, struct lan9645x_port,
+ host_flood_work);
+ struct lan9645x *lan9645x = p->lan9645x;
+
+ mutex_lock(&lan9645x->fwd_domain_lock);
+ __lan9645x_port_mark_host_flood(lan9645x, p->chip_port,
+ p->host_flood_uc, p->host_flood_mc);
+ __lan9645x_port_set_host_flood(lan9645x);
+ mutex_unlock(&lan9645x->fwd_domain_lock);
+}
+
+/* Called in atomic context. */
+static void lan9645x_port_set_host_flood(struct dsa_switch *ds, int port,
+ bool uc, bool mc)
+{
+ struct lan9645x *lan9645x = ds->priv;
+ struct lan9645x_port *p;
+
+ p = lan9645x_to_port(lan9645x, port);
+
+ p->host_flood_uc = uc;
+ p->host_flood_mc = mc;
+ queue_work(lan9645x->owq, &p->host_flood_work);
+}
+
+static int lan9645x_port_bridge_join(struct dsa_switch *ds, int port,
+ struct dsa_bridge bridge,
+ bool *tx_fwd_offload,
+ struct netlink_ext_ack *extack)
+{
+ struct lan9645x *lan9645x = ds->priv;
+ struct lan9645x_port *p;
+
+ p = lan9645x_to_port(lan9645x, port);
+
+ if (lan9645x->bridge && lan9645x->bridge != bridge.dev) {
+ NL_SET_ERR_MSG_MOD(extack, "Only one bridge supported");
+ return -EBUSY;
+ }
+
+ mutex_lock(&lan9645x->fwd_domain_lock);
+ /* First bridged port sets bridge dev */
+ if (!lan9645x->bridge_mask)
+ lan9645x->bridge = bridge.dev;
+
+ lan9645x->bridge_mask |= BIT(p->chip_port);
+ __lan9645x_port_set_host_flood(lan9645x);
+
+ mutex_unlock(&lan9645x->fwd_domain_lock);
+
+ /* Later: stp_state_set updates forwarding */
+
+ return 0;
+}
+
+static void lan9645x_port_bridge_stp_state_set(struct dsa_switch *ds, int port,
+ u8 state)
+{
+ struct lan9645x *lan9645x;
+ struct lan9645x_port *p;
+ bool learn_ena;
+
+ lan9645x = ds->priv;
+ p = lan9645x_to_port(lan9645x, port);
+
+ mutex_lock(&lan9645x->fwd_domain_lock);
+
+ p->stp_state = state;
+
+ if (state == BR_STATE_FORWARDING)
+ lan9645x->bridge_fwd_mask |= BIT(p->chip_port);
+ else
+ lan9645x->bridge_fwd_mask &= ~BIT(p->chip_port);
+
+ learn_ena = (state == BR_STATE_LEARNING ||
+ state == BR_STATE_FORWARDING) && p->learn_ena;
+
+ lan_rmw(ANA_PORT_CFG_LEARN_ENA_SET(learn_ena),
+ ANA_PORT_CFG_LEARN_ENA, lan9645x,
+ ANA_PORT_CFG(p->chip_port));
+
+ lan9645x_update_fwd_mask(lan9645x);
+ mutex_unlock(&lan9645x->fwd_domain_lock);
+}
+
+static void lan9645x_port_bridge_leave(struct dsa_switch *ds, int port,
+ struct dsa_bridge bridge)
+{
+ struct lan9645x *lan9645x = ds->priv;
+ struct lan9645x_port *p;
+
+ p = lan9645x_to_port(lan9645x, port);
+
+ mutex_lock(&lan9645x->fwd_domain_lock);
+
+ lan9645x->bridge_mask &= ~BIT(p->chip_port);
+
+ /* Last port leaving clears bridge dev */
+ if (!lan9645x->bridge_mask)
+ lan9645x->bridge = NULL;
+
+ __lan9645x_port_set_host_flood(lan9645x);
+ lan9645x_update_fwd_mask(lan9645x);
+
+ mutex_unlock(&lan9645x->fwd_domain_lock);
+}
+
static const struct dsa_switch_ops lan9645x_switch_ops = {
.get_tag_protocol = lan9645x_get_tag_protocol,

@@ -270,6 +545,15 @@ static const struct dsa_switch_ops lan9645x_switch_ops = {
/* MTU */
.port_change_mtu = lan9645x_change_mtu,
.port_max_mtu = lan9645x_get_max_mtu,
+
+ /* Bridge integration */
+ .set_ageing_time = lan9645x_set_ageing_time,
+ .port_pre_bridge_flags = lan9645x_port_pre_bridge_flags,
+ .port_bridge_flags = lan9645x_port_bridge_flags,
+ .port_bridge_join = lan9645x_port_bridge_join,
+ .port_bridge_leave = lan9645x_port_bridge_leave,
+ .port_stp_state_set = lan9645x_port_bridge_stp_state_set,
+ .port_set_host_flood = lan9645x_port_set_host_flood,
};

static int lan9645x_request_target_regmaps(struct lan9645x *lan9645x)
@@ -353,6 +637,7 @@ static int lan9645x_probe(struct platform_device *pdev)

p->lan9645x = lan9645x;
p->chip_port = port;
+ INIT_WORK(&p->host_flood_work, lan9645x_host_flood_work_fn);
lan9645x->ports[port] = p;
}

diff --git a/drivers/net/dsa/microchip/lan9645x/lan9645x_main.h b/drivers/net/dsa/microchip/lan9645x/lan9645x_main.h
index 5a3204b72e83..ddb5009f88bf 100644
--- a/drivers/net/dsa/microchip/lan9645x/lan9645x_main.h
+++ b/drivers/net/dsa/microchip/lan9645x/lan9645x_main.h
@@ -155,6 +155,11 @@ struct lan9645x {
struct dsa_switch *ds;
struct regmap *rmap[NUM_TARGETS];

+ u16 host_flood_uc_mask;
+ u16 host_flood_mc_mask;
+
+ struct workqueue_struct *owq;
+
int shared_queue_sz;

/* NPI chip_port */
@@ -163,6 +168,12 @@ struct lan9645x {
u8 num_phys_ports;
struct lan9645x_port **ports;

+ /* Forwarding Database */
+ struct net_device *bridge; /* Only support single bridge */
+ u16 bridge_mask; /* Mask for bridged ports */
+ u16 bridge_fwd_mask; /* Mask for forwarding bridged ports */
+ struct mutex fwd_domain_lock; /* lock forwarding configuration */
+
int num_port_dis;
bool dd_dis;
bool tsn_dis;
@@ -172,9 +183,15 @@ struct lan9645x_port {
struct lan9645x *lan9645x;

u8 chip_port;
+ u8 stp_state;
+ bool learn_ena;

bool rx_internal_delay;
bool tx_internal_delay;
+
+ struct work_struct host_flood_work;
+ bool host_flood_uc;
+ bool host_flood_mc;
};

extern const struct phylink_mac_ops lan9645x_phylink_mac_ops;
@@ -221,6 +238,11 @@ static inline struct lan9645x_port *lan9645x_to_port(struct lan9645x *lan9645x,
return lan9645x->ports[port];
}

+static inline bool lan9645x_port_is_bridged(struct lan9645x_port *p)
+{
+ return p && (p->lan9645x->bridge_mask & BIT(p->chip_port));
+}
+
static inline struct regmap *lan_tgt2rmap(struct lan9645x *lan9645x,
enum lan9645x_target t, int tinst)
{

--
2.52.0