[PATCH V2 2/3] net-next: dsa: add multi cpu port support

[John Crispin]

Some boards have two CPU interfaces connected to the switch, e.g. WiFi
access points, with 1 port labeled WAN, 4 ports labeled lan1-lan4, and
two port connected to the SoC.

This patch extends DSA to allows both CPU ports to be used. The "cpu"
node in the DSA tree can now have a phandle to the host interface it
connects to. Each user port can have a phandle to a cpu port which
should be used for traffic between the port and the CPU. Thus simple
load sharing over the two CPU ports can be achieved.

Signed-off-by: John Crispin <john@xxxxxxxxxxx>
---
 include/net/dsa.h  | 21 ++++++++++++++++++++-
 net/dsa/dsa2.c     | 35 +++++++++++++++++++++++++++++++----
 net/dsa/dsa_priv.h |  1 +
 net/dsa/slave.c    | 26 ++++++++++++++++----------
 4 files changed, 68 insertions(+), 15 deletions(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index c0e567c0c824..d2994bd2c507 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -186,6 +186,8 @@ struct dsa_port {
 	u8			stp_state;
 	struct net_device	*bridge_dev;
 	struct devlink_port	devlink_port;
+	struct net_device	*ethernet;
+	int			upstream;
 };
 
 struct dsa_switch {
@@ -251,7 +253,7 @@ struct dsa_switch {
 
 static inline bool dsa_is_cpu_port(struct dsa_switch *ds, int p)
 {
-	return ds->dst->cpu_dp == &ds->ports[p];
+	return !!(ds->cpu_port_mask & (1 << p));
 }
 
 static inline bool dsa_is_dsa_port(struct dsa_switch *ds, int p)
@@ -269,6 +271,11 @@ static inline bool dsa_is_port_initialized(struct dsa_switch *ds, int p)
 	return ds->enabled_port_mask & (1 << p) && ds->ports[p].netdev;
 }
 
+static inline bool dsa_is_upstream_port(struct dsa_switch *ds, int p)
+{
+	return dsa_is_cpu_port(ds, p) || dsa_is_dsa_port(ds, p);
+}
+
 static inline u8 dsa_upstream_port(struct dsa_switch *ds)
 {
 	struct dsa_switch_tree *dst = ds->dst;
@@ -285,6 +292,18 @@ static inline u8 dsa_upstream_port(struct dsa_switch *ds)
 		return ds->rtable[dst->cpu_dp->ds->index];
 }
 
+static inline u8 dsa_port_upstream_port(struct dsa_switch *ds, int port)
+{
+	/*
+	 * If this port has a specific upstream cpu port, use it,
+	 * otherwise use the switch default.
+	 */
+	if (ds->ports[port].upstream)
+		return ds->ports[port].upstream;
+	else
+		return dsa_upstream_port(ds);
+}
+
 struct dsa_switch_ops {
 	/*
 	 * Legacy probing.
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index 4301f52e4f5a..8b13aa735c40 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -253,8 +253,6 @@ static int dsa_cpu_port_apply(struct dsa_port *port, u32 index,
 		return err;
 	}
 
-	ds->cpu_port_mask |= BIT(index);
-
 	memset(&ds->ports[index].devlink_port, 0,
 	       sizeof(ds->ports[index].devlink_port));
 	err = devlink_port_register(ds->devlink, &ds->ports[index].devlink_port,
@@ -269,6 +267,10 @@ static void dsa_cpu_port_unapply(struct dsa_port *port, u32 index,
 	dsa_cpu_dsa_destroy(port);
 	ds->cpu_port_mask &= ~BIT(index);
 
+	if (ds->ports[index].ethernet) {
+		dev_put(ds->ports[index].ethernet);
+		ds->ports[index].ethernet = NULL;
+	}
 }
 
 static int dsa_user_port_apply(struct dsa_port *port, u32 index,
@@ -530,6 +532,29 @@ static int dsa_cpu_parse(struct dsa_port *port, u32 index,
 
 	dst->rcv = dst->tag_ops->rcv;
 
+	dev_hold(ethernet_dev);
+	ds->ports[index].ethernet = ethernet_dev;
+	ds->cpu_port_mask |= BIT(index);
+
+	return 0;
+}
+
+static int dsa_user_parse(struct device_node *port, u32 index,
+			  struct dsa_switch *ds)
+{
+	struct device_node *cpu_port;
+	const unsigned int *cpu_port_reg;
+	int cpu_port_index;
+
+	cpu_port = of_parse_phandle(port, "cpu", 0);
+	if (cpu_port) {
+		cpu_port_reg = of_get_property(cpu_port, "reg", NULL);
+		if (!cpu_port_reg)
+			return -EINVAL;
+		cpu_port_index = be32_to_cpup(cpu_port_reg);
+		ds->ports[index].upstream = cpu_port_index;
+	}
+
 	return 0;
 }
 
@@ -544,11 +569,13 @@ static int dsa_ds_parse(struct dsa_switch_tree *dst, struct dsa_switch *ds)
 		if (!dsa_port_is_valid(port))
 			continue;
 
-		if (dsa_port_is_cpu(port)) {
+		if (dsa_port_is_cpu(port))
 			err = dsa_cpu_parse(port, index, dst, ds);
+		else if (dsa_is_normal_port(port))
+			err = dsa_user_parse(port->dn, index,  ds);
+
 			if (err)
 				return err;
-		}
 	}
 
 	pr_info("DSA: switch %d %d parsed\n", dst->tree, ds->index);
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index c1d4180651af..91fdc16befb2 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -78,6 +78,7 @@ struct dsa_slave_priv {
 
 	/* DSA port data, such as switch, port index, etc. */
 	struct dsa_port		*dp;
+	struct net_device	*master;
 
 	/*
 	 * The phylib phy_device pointer for the PHY connected
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 887e26695519..45f17f35ced1 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -66,7 +66,7 @@ static int dsa_slave_get_iflink(const struct net_device *dev)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
 
-	return p->dp->ds->dst->master_netdev->ifindex;
+	return p->master->ifindex;
 }
 
 static inline bool dsa_port_is_bridged(struct dsa_port *dp)
@@ -77,7 +77,7 @@ static inline bool dsa_port_is_bridged(struct dsa_port *dp)
 static int dsa_slave_open(struct net_device *dev)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
-	struct net_device *master = p->dp->ds->dst->master_netdev;
+	struct net_device *master = p->master;
 	struct dsa_switch *ds = p->dp->ds;
 	u8 stp_state = dsa_port_is_bridged(p->dp) ?
 			BR_STATE_BLOCKING : BR_STATE_FORWARDING;
@@ -132,7 +132,7 @@ static int dsa_slave_open(struct net_device *dev)
 static int dsa_slave_close(struct net_device *dev)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
-	struct net_device *master = p->dp->ds->dst->master_netdev;
+	struct net_device *master = p->master;
 	struct dsa_switch *ds = p->dp->ds;
 
 	if (p->phy)
@@ -159,7 +159,7 @@ static int dsa_slave_close(struct net_device *dev)
 static void dsa_slave_change_rx_flags(struct net_device *dev, int change)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
-	struct net_device *master = p->dp->ds->dst->master_netdev;
+	struct net_device *master = p->master;
 
 	if (change & IFF_ALLMULTI)
 		dev_set_allmulti(master, dev->flags & IFF_ALLMULTI ? 1 : -1);
@@ -170,7 +170,7 @@ static void dsa_slave_change_rx_flags(struct net_device *dev, int change)
 static void dsa_slave_set_rx_mode(struct net_device *dev)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
-	struct net_device *master = p->dp->ds->dst->master_netdev;
+	struct net_device *master = p->master;
 
 	dev_mc_sync(master, dev);
 	dev_uc_sync(master, dev);
@@ -179,7 +179,7 @@ static void dsa_slave_set_rx_mode(struct net_device *dev)
 static int dsa_slave_set_mac_address(struct net_device *dev, void *a)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
-	struct net_device *master = p->dp->ds->dst->master_netdev;
+	struct net_device *master = p->master;
 	struct sockaddr *addr = a;
 	int err;
 
@@ -376,7 +376,7 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Queue the SKB for transmission on the parent interface, but
 	 * do not modify its EtherType
 	 */
-	nskb->dev = p->dp->ds->dst->master_netdev;
+	nskb->dev = p->master;
 	dev_queue_xmit(nskb);
 
 	return NETDEV_TX_OK;
@@ -685,7 +685,7 @@ static int dsa_slave_netpoll_setup(struct net_device *dev,
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
 	struct dsa_switch *ds = p->dp->ds;
-	struct net_device *master = ds->dst->master_netdev;
+	struct net_device *master = p->master;
 	struct netpoll *netpoll;
 	int err = 0;
 
@@ -1140,11 +1140,16 @@ int dsa_slave_create(struct dsa_switch *ds, struct device *parent,
 	struct net_device *master;
 	struct net_device *slave_dev;
 	struct dsa_slave_priv *p;
+	int port_cpu = ds->ports[port].upstream;
 	int ret;
 
-	master = ds->dst->master_netdev;
-	if (ds->master_netdev)
+	if (port_cpu && ds->ports[port_cpu].ethernet)
+		master = ds->ports[port_cpu].ethernet;
+	else if (ds->master_netdev)
 		master = ds->master_netdev;
+	else
+		master = ds->dst->master_netdev;
+	master->dsa_ptr = (void *)ds->dst;
 
 	slave_dev = alloc_netdev(sizeof(struct dsa_slave_priv), name,
 				 NET_NAME_UNKNOWN, ether_setup);
@@ -1173,6 +1178,7 @@ int dsa_slave_create(struct dsa_switch *ds, struct device *parent,
 	p->dp = &ds->ports[port];
 	INIT_LIST_HEAD(&p->mall_tc_list);
 	p->xmit = dst->tag_ops->xmit;
+	p->master = master;
 
 	p->old_pause = -1;
 	p->old_link = -1;
-- 
2.11.0