net: dsa: qca8k: add LAG support

Add LAG support to this switch. In Documentation this is described as
trunk mode. A max of 4 LAGs are supported and each can support up to 4
port. The current tx mode supported is Hash mode with both L2 and L2+3
mode.
When no port are present in the trunk, the trunk is disabled in the
switch.
When a port is disconnected, the traffic is redirected to the other
available port.
The hash mode is global and each LAG require to have the same hash mode
set. To change the hash mode when multiple LAG are configured, it's
required to remove each LAG and set the desired hash mode to the last.
An error is printed when it's asked to set a not supported hadh mode.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 177 insertions, 0 deletions

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index bd9d756f4001..6516df08a5d5 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -1336,6 +1336,9 @@ qca8k_setup(struct dsa_switch *ds)
 	ds->ageing_time_min = 7000;
 	ds->ageing_time_max = 458745000;
 
+	/* Set max number of LAGs supported */
+	ds->num_lag_ids = QCA8K_NUM_LAGS;
+
 	return 0;
 }
 
@@ -2203,6 +2206,178 @@ qca8k_get_tag_protocol(struct dsa_switch *ds, int port,
 	return DSA_TAG_PROTO_QCA;
 }
 
+static bool
+qca8k_lag_can_offload(struct dsa_switch *ds,
+		      struct net_device *lag,
+		      struct netdev_lag_upper_info *info)
+{
+	struct dsa_port *dp;
+	int id, members = 0;
+
+	id = dsa_lag_id(ds->dst, lag);
+	if (id < 0 || id >= ds->num_lag_ids)
+		return false;
+
+	dsa_lag_foreach_port(dp, ds->dst, lag)
+		/* Includes the port joining the LAG */
+		members++;
+
+	if (members > QCA8K_NUM_PORTS_FOR_LAG)
+		return false;
+
+	if (info->tx_type != NETDEV_LAG_TX_TYPE_HASH)
+		return false;
+
+	if (info->hash_type != NETDEV_LAG_HASH_L2 ||
+	    info->hash_type != NETDEV_LAG_HASH_L23)
+		return false;
+
+	return true;
+}
+
+static int
+qca8k_lag_setup_hash(struct dsa_switch *ds,
+		     struct net_device *lag,
+		     struct netdev_lag_upper_info *info)
+{
+	struct qca8k_priv *priv = ds->priv;
+	bool unique_lag = true;
+	int i, id;
+	u32 hash;
+
+	id = dsa_lag_id(ds->dst, lag);
+
+	switch (info->hash_type) {
+	case NETDEV_LAG_HASH_L23:
+		hash |= QCA8K_TRUNK_HASH_SIP_EN;
+		hash |= QCA8K_TRUNK_HASH_DIP_EN;
+		fallthrough;
+	case NETDEV_LAG_HASH_L2:
+		hash |= QCA8K_TRUNK_HASH_SA_EN;
+		hash |= QCA8K_TRUNK_HASH_DA_EN;
+		break;
+	default: /* We should NEVER reach this */
+		return -EOPNOTSUPP;
+	}
+
+	/* Check if we are the unique configured LAG */
+	dsa_lags_foreach_id(i, ds->dst)
+		if (i != id && dsa_lag_dev(ds->dst, i)) {
+			unique_lag = false;
+			break;
+		}
+
+	/* Hash Mode is global. Make sure the same Hash Mode
+	 * is set to all the 4 possible lag.
+	 * If we are the unique LAG we can set whatever hash
+	 * mode we want.
+	 * To change hash mode it's needed to remove all LAG
+	 * and change the mode with the latest.
+	 */
+	if (unique_lag) {
+		priv->lag_hash_mode = hash;
+	} else if (priv->lag_hash_mode != hash) {
+		netdev_err(lag, "Error: Mismateched Hash Mode across different lag is not supported\n");
+		return -EOPNOTSUPP;
+	}
+
+	return regmap_update_bits(priv->regmap, QCA8K_TRUNK_HASH_EN_CTRL,
+				  QCA8K_TRUNK_HASH_MASK, hash);
+}
+
+static int
+qca8k_lag_refresh_portmap(struct dsa_switch *ds, int port,
+			  struct net_device *lag, bool delete)
+{
+	struct qca8k_priv *priv = ds->priv;
+	int ret, id, i;
+	u32 val;
+
+	id = dsa_lag_id(ds->dst, lag);
+
+	/* Read current port member */
+	ret = regmap_read(priv->regmap, QCA8K_REG_GOL_TRUNK_CTRL0, &val);
+	if (ret)
+		return ret;
+
+	/* Shift val to the correct trunk */
+	val >>= QCA8K_REG_GOL_TRUNK_SHIFT(id);
+	val &= QCA8K_REG_GOL_TRUNK_MEMBER_MASK;
+	if (delete)
+		val &= ~BIT(port);
+	else
+		val |= BIT(port);
+
+	/* Update port member. With empty portmap disable trunk */
+	ret = regmap_update_bits(priv->regmap, QCA8K_REG_GOL_TRUNK_CTRL0,
+				 QCA8K_REG_GOL_TRUNK_MEMBER(id) |
+				 QCA8K_REG_GOL_TRUNK_EN(id),
+				 !val << QCA8K_REG_GOL_TRUNK_SHIFT(id) |
+				 val << QCA8K_REG_GOL_TRUNK_SHIFT(id));
+
+	/* Search empty member if adding or port on deleting */
+	for (i = 0; i < QCA8K_NUM_PORTS_FOR_LAG; i++) {
+		ret = regmap_read(priv->regmap, QCA8K_REG_GOL_TRUNK_CTRL(id), &val);
+		if (ret)
+			return ret;
+
+		val >>= QCA8K_REG_GOL_TRUNK_ID_MEM_ID_SHIFT(id, i);
+		val &= QCA8K_REG_GOL_TRUNK_ID_MEM_ID_MASK;
+
+		if (delete) {
+			/* If port flagged to be disabled assume this member is
+			 * empty
+			 */
+			if (val != QCA8K_REG_GOL_TRUNK_ID_MEM_ID_EN_MASK)
+				continue;
+
+			val &= QCA8K_REG_GOL_TRUNK_ID_MEM_ID_PORT_MASK;
+			if (val != port)
+				continue;
+		} else {
+			/* If port flagged to be enabled assume this member is
+			 * already set
+			 */
+			if (val == QCA8K_REG_GOL_TRUNK_ID_MEM_ID_EN_MASK)
+				continue;
+		}
+
+		/* We have found the member to add/remove */
+		break;
+	}
+
+	/* Set port in the correct port mask or disable port if in delete mode */
+	return regmap_update_bits(priv->regmap, QCA8K_REG_GOL_TRUNK_CTRL(id),
+				  QCA8K_REG_GOL_TRUNK_ID_MEM_ID_EN(id, i) |
+				  QCA8K_REG_GOL_TRUNK_ID_MEM_ID_PORT(id, i),
+				  !delete << QCA8K_REG_GOL_TRUNK_ID_MEM_ID_SHIFT(id, i) |
+				  port << QCA8K_REG_GOL_TRUNK_ID_MEM_ID_SHIFT(id, i));
+}
+
+static int
+qca8k_port_lag_join(struct dsa_switch *ds, int port,
+		    struct net_device *lag,
+		    struct netdev_lag_upper_info *info)
+{
+	int ret;
+
+	if (!qca8k_lag_can_offload(ds, lag, info))
+		return -EOPNOTSUPP;
+
+	ret = qca8k_lag_setup_hash(ds, lag, info);
+	if (ret)
+		return ret;
+
+	return qca8k_lag_refresh_portmap(ds, port, lag, false);
+}
+
+static int
+qca8k_port_lag_leave(struct dsa_switch *ds, int port,
+		     struct net_device *lag)
+{
+	return qca8k_lag_refresh_portmap(ds, port, lag, true);
+}
+
 static const struct dsa_switch_ops qca8k_switch_ops = {
 	.get_tag_protocol	= qca8k_get_tag_protocol,
 	.setup			= qca8k_setup,
@@ -2236,6 +2411,8 @@ static const struct dsa_switch_ops qca8k_switch_ops = {
 	.phylink_mac_link_down	= qca8k_phylink_mac_link_down,
 	.phylink_mac_link_up	= qca8k_phylink_mac_link_up,
 	.get_phy_flags		= qca8k_get_phy_flags,
+	.port_lag_join		= qca8k_port_lag_join,
+	.port_lag_leave		= qca8k_port_lag_leave,
 };
 
 static int qca8k_read_switch_id(struct qca8k_priv *priv)