mlxsw: spectrum: Introduce port splitting

Allow a user to split or unsplit a port using the newly introduced
devlink ops.

Once split, the original netdev is destroyed and 2 or 4 others are
created, according to user configuration. The new ports are like any
other port, with the sole difference of supporting a lower maximum
speed. When unsplit, the reverse process takes place.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: idosch

drivers/net/ethernet/mellanox/mlxsw/port.h

@@ -59,6 +59,8 @@
 
 #define MLXSW_PORT_DONT_CARE		(MLXSW_PORT_MAX_PORTS)
 
+#define MLXSW_PORT_MODULE_MAX_WIDTH	4
+
 enum mlxsw_port_admin_status {
 	MLXSW_PORT_ADMIN_STATUS_UP = 1,
 	MLXSW_PORT_ADMIN_STATUS_DOWN = 2,

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -321,6 +321,22 @@ static int mlxsw_sp_port_module_info_get(struct mlxsw_sp *mlxsw_sp,
 	return 0;
 }
 
+static int mlxsw_sp_port_module_map(struct mlxsw_sp *mlxsw_sp, u8 local_port,
+				    u8 module, u8 width, u8 lane)
+{
+	char pmlp_pl[MLXSW_REG_PMLP_LEN];
+	int i;
+
+	mlxsw_reg_pmlp_pack(pmlp_pl, local_port);
+	mlxsw_reg_pmlp_width_set(pmlp_pl, width);
+	for (i = 0; i < width; i++) {
+		mlxsw_reg_pmlp_module_set(pmlp_pl, i, module);
+		mlxsw_reg_pmlp_tx_lane_set(pmlp_pl, i, lane + i);  /* Rx & Tx */
+	}
+
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(pmlp), pmlp_pl);
+}
+
 static int mlxsw_sp_port_module_unmap(struct mlxsw_sp *mlxsw_sp, u8 local_port)
 {
 	char pmlp_pl[MLXSW_REG_PMLP_LEN];
@@ -1284,6 +1300,18 @@ static u32 mlxsw_sp_to_ptys_speed(u32 speed)
 	return ptys_proto;
 }
 
+static u32 mlxsw_sp_to_ptys_upper_speed(u32 upper_speed)
+{
+	u32 ptys_proto = 0;
+	int i;
+
+	for (i = 0; i < MLXSW_SP_PORT_LINK_MODE_LEN; i++) {
+		if (mlxsw_sp_port_link_mode[i].speed <= upper_speed)
+			ptys_proto |= mlxsw_sp_port_link_mode[i].mask;
+	}
+	return ptys_proto;
+}
+
 static int mlxsw_sp_port_set_settings(struct net_device *dev,
 				      struct ethtool_cmd *cmd)
 {
@@ -1360,7 +1388,22 @@ static const struct ethtool_ops mlxsw_sp_port_ethtool_ops = {
 	.set_settings		= mlxsw_sp_port_set_settings,
 };
 
-static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port)
+static int
+mlxsw_sp_port_speed_by_width_set(struct mlxsw_sp_port *mlxsw_sp_port, u8 width)
+{
+	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
+	u32 upper_speed = MLXSW_SP_PORT_BASE_SPEED * width;
+	char ptys_pl[MLXSW_REG_PTYS_LEN];
+	u32 eth_proto_admin;
+
+	eth_proto_admin = mlxsw_sp_to_ptys_upper_speed(upper_speed);
+	mlxsw_reg_ptys_pack(ptys_pl, mlxsw_sp_port->local_port,
+			    eth_proto_admin);
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ptys), ptys_pl);
+}
+
+static int __mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port,
+				  bool split, u8 module, u8 width)
 {
 	struct devlink *devlink = priv_to_devlink(mlxsw_sp->core);
 	struct mlxsw_sp_port *mlxsw_sp_port;
@@ -1376,6 +1419,7 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port)
 	mlxsw_sp_port->dev = dev;
 	mlxsw_sp_port->mlxsw_sp = mlxsw_sp;
 	mlxsw_sp_port->local_port = local_port;
+	mlxsw_sp_port->split = split;
 	bytes = DIV_ROUND_UP(VLAN_N_VID, BITS_PER_BYTE);
 	mlxsw_sp_port->active_vlans = kzalloc(bytes, GFP_KERNEL);
 	if (!mlxsw_sp_port->active_vlans) {
@@ -1417,6 +1461,8 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port)
 	dev->hard_header_len += MLXSW_TXHDR_LEN;
 
 	devlink_port = &mlxsw_sp_port->devlink_port;
+	if (mlxsw_sp_port->split)
+		devlink_port_split_set(devlink_port, module);
 	err = devlink_port_register(devlink, devlink_port, local_port);
 	if (err) {
 		dev_err(mlxsw_sp->bus_info->dev, "Port %d: Failed to register devlink port\n",
@@ -1438,6 +1484,13 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port)
 		goto err_port_swid_set;
 	}
 
+	err = mlxsw_sp_port_speed_by_width_set(mlxsw_sp_port, width);
+	if (err) {
+		dev_err(mlxsw_sp->bus_info->dev, "Port %d: Failed to enable speeds\n",
+			mlxsw_sp_port->local_port);
+		goto err_port_speed_by_width_set;
+	}
+
 	err = mlxsw_sp_port_mtu_set(mlxsw_sp_port, ETH_DATA_LEN);
 	if (err) {
 		dev_err(mlxsw_sp->bus_info->dev, "Port %d: Failed to set MTU\n",
@@ -1479,6 +1532,7 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port)
 err_port_buffers_init:
 err_port_admin_status_set:
 err_port_mtu_set:
+err_port_speed_by_width_set:
 err_port_swid_set:
 err_port_system_port_mapping_set:
 	devlink_port_unregister(&mlxsw_sp_port->devlink_port);
@@ -1494,6 +1548,28 @@ static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port)
 	return err;
 }
 
+static int mlxsw_sp_port_create(struct mlxsw_sp *mlxsw_sp, u8 local_port,
+				bool split, u8 module, u8 width, u8 lane)
+{
+	int err;
+
+	err = mlxsw_sp_port_module_map(mlxsw_sp, local_port, module, width,
+				       lane);
+	if (err)
+		return err;
+
+	err = __mlxsw_sp_port_create(mlxsw_sp, local_port, split, module,
+				     width);
+	if (err)
+		goto err_port_create;
+
+	return 0;
+
+err_port_create:
+	mlxsw_sp_port_module_unmap(mlxsw_sp, local_port);
+	return err;
+}
+
 static void mlxsw_sp_port_vports_fini(struct mlxsw_sp_port *mlxsw_sp_port)
 {
 	struct net_device *dev = mlxsw_sp_port->dev;
@@ -1562,7 +1638,7 @@ static int mlxsw_sp_ports_create(struct mlxsw_sp *mlxsw_sp)
 		if (!width)
 			continue;
 		mlxsw_sp->port_to_module[i] = module;
-		err = mlxsw_sp_port_create(mlxsw_sp, i);
+		err = __mlxsw_sp_port_create(mlxsw_sp, i, false, module, width);
 		if (err)
 			goto err_port_create;
 	}
@@ -1576,6 +1652,137 @@ static int mlxsw_sp_ports_create(struct mlxsw_sp *mlxsw_sp)
 	return err;
 }
 
+static u8 mlxsw_sp_cluster_base_port_get(u8 local_port)
+{
+	u8 offset = (local_port - 1) % MLXSW_SP_PORTS_PER_CLUSTER_MAX;
+
+	return local_port - offset;
+}
+
+static int mlxsw_sp_port_split(void *priv, u8 local_port, unsigned int count)
+{
+	struct mlxsw_sp *mlxsw_sp = priv;
+	struct mlxsw_sp_port *mlxsw_sp_port;
+	u8 width = MLXSW_PORT_MODULE_MAX_WIDTH / count;
+	u8 module, cur_width, base_port;
+	int i;
+	int err;
+
+	mlxsw_sp_port = mlxsw_sp->ports[local_port];
+	if (!mlxsw_sp_port) {
+		dev_err(mlxsw_sp->bus_info->dev, "Port number \"%d\" does not exist\n",
+			local_port);
+		return -EINVAL;
+	}
+
+	if (count != 2 && count != 4) {
+		netdev_err(mlxsw_sp_port->dev, "Port can only be split into 2 or 4 ports\n");
+		return -EINVAL;
+	}
+
+	err = mlxsw_sp_port_module_info_get(mlxsw_sp, local_port, &module,
+					    &cur_width);
+	if (err) {
+		netdev_err(mlxsw_sp_port->dev, "Failed to get port's width\n");
+		return err;
+	}
+
+	if (cur_width != MLXSW_PORT_MODULE_MAX_WIDTH) {
+		netdev_err(mlxsw_sp_port->dev, "Port cannot be split further\n");
+		return -EINVAL;
+	}
+
+	/* Make sure we have enough slave (even) ports for the split. */
+	if (count == 2) {
+		base_port = local_port;
+		if (mlxsw_sp->ports[base_port + 1]) {
+			netdev_err(mlxsw_sp_port->dev, "Invalid split configuration\n");
+			return -EINVAL;
+		}
+	} else {
+		base_port = mlxsw_sp_cluster_base_port_get(local_port);
+		if (mlxsw_sp->ports[base_port + 1] ||
+		    mlxsw_sp->ports[base_port + 3]) {
+			netdev_err(mlxsw_sp_port->dev, "Invalid split configuration\n");
+			return -EINVAL;
+		}
+	}
+
+	for (i = 0; i < count; i++)
+		mlxsw_sp_port_remove(mlxsw_sp, base_port + i);
+
+	for (i = 0; i < count; i++) {
+		err = mlxsw_sp_port_create(mlxsw_sp, base_port + i, true,
+					   module, width, i * width);
+		if (err) {
+			dev_err(mlxsw_sp->bus_info->dev, "Failed to create split port\n");
+			goto err_port_create;
+		}
+	}
+
+	return 0;
+
+err_port_create:
+	for (i--; i >= 0; i--)
+		mlxsw_sp_port_remove(mlxsw_sp, base_port + i);
+	for (i = 0; i < count / 2; i++) {
+		module = mlxsw_sp->port_to_module[base_port + i * 2];
+		mlxsw_sp_port_create(mlxsw_sp, base_port + i * 2, false,
+				     module, MLXSW_PORT_MODULE_MAX_WIDTH, 0);
+	}
+	return err;
+}
+
+static int mlxsw_sp_port_unsplit(void *priv, u8 local_port)
+{
+	struct mlxsw_sp *mlxsw_sp = priv;
+	struct mlxsw_sp_port *mlxsw_sp_port;
+	u8 module, cur_width, base_port;
+	unsigned int count;
+	int i;
+	int err;
+
+	mlxsw_sp_port = mlxsw_sp->ports[local_port];
+	if (!mlxsw_sp_port) {
+		dev_err(mlxsw_sp->bus_info->dev, "Port number \"%d\" does not exist\n",
+			local_port);
+		return -EINVAL;
+	}
+
+	if (!mlxsw_sp_port->split) {
+		netdev_err(mlxsw_sp_port->dev, "Port wasn't split\n");
+		return -EINVAL;
+	}
+
+	err = mlxsw_sp_port_module_info_get(mlxsw_sp, local_port, &module,
+					    &cur_width);
+	if (err) {
+		netdev_err(mlxsw_sp_port->dev, "Failed to get port's width\n");
+		return err;
+	}
+	count = cur_width == 1 ? 4 : 2;
+
+	base_port = mlxsw_sp_cluster_base_port_get(local_port);
+
+	/* Determine which ports to remove. */
+	if (count == 2 && local_port >= base_port + 2)
+		base_port = base_port + 2;
+
+	for (i = 0; i < count; i++)
+		mlxsw_sp_port_remove(mlxsw_sp, base_port + i);
+
+	for (i = 0; i < count / 2; i++) {
+		module = mlxsw_sp->port_to_module[base_port + i * 2];
+		err = mlxsw_sp_port_create(mlxsw_sp, base_port + i * 2, false,
+					   module, MLXSW_PORT_MODULE_MAX_WIDTH,
+					   0);
+		if (err)
+			dev_err(mlxsw_sp->bus_info->dev, "Failed to reinstantiate port\n");
+	}
+
+	return 0;
+}
+
 static void mlxsw_sp_pude_event_func(const struct mlxsw_reg_info *reg,
 				     char *pude_pl, void *priv)
 {
@@ -1999,6 +2206,8 @@ static struct mlxsw_driver mlxsw_sp_driver = {
 	.priv_size		= sizeof(struct mlxsw_sp),
 	.init			= mlxsw_sp_init,
 	.fini			= mlxsw_sp_fini,
+	.port_split		= mlxsw_sp_port_split,
+	.port_unsplit		= mlxsw_sp_port_unsplit,
 	.txhdr_construct	= mlxsw_sp_txhdr_construct,
 	.txhdr_len		= MLXSW_TXHDR_LEN,
 	.profile		= &mlxsw_sp_config_profile,

drivers/net/ethernet/mellanox/mlxsw/spectrum.h

@@ -58,6 +58,10 @@
 
 #define MLXSW_SP_MID_MAX 7000
 
+#define MLXSW_SP_PORTS_PER_CLUSTER_MAX 4
+
+#define MLXSW_SP_PORT_BASE_SPEED 25000	/* Mb/s */
+
 struct mlxsw_sp_port;
 
 struct mlxsw_sp_upper {
@@ -151,7 +155,8 @@ struct mlxsw_sp_port {
 	   learning_sync:1,
 	   uc_flood:1,
 	   bridged:1,
-	   lagged:1;
+	   lagged:1,
+	   split:1;
 	u16 pvid;
 	u16 lag_id;
 	struct {