[RFC PATCH net-next 5/8] devlink: Add a new devlink port lanes attribute and pass to netlink

[Danielle Ratson <danieller@mellanox.com>]

Add a new devlink port attribute that indicates the port's number of lanes.

Drivers are expected to set it via devlink_port_attrs_set(), before
registering the port.

The attribute is not passed to user space in case the number of lanes is
invalid (0).

Signed-off-by: Danielle Ratson <danieller@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlxsw/core.c | 1 +
 include/net/devlink.h                      | 1 +
 include/uapi/linux/devlink.h               | 2 ++
 net/core/devlink.c                         | 7 +++++++
 4 files changed, 11 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c
index f44cb1a537f3..6cde196f6b70 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
@@ -2134,6 +2134,7 @@ static int __mlxsw_core_port_init(struct mlxsw_core *mlxsw_core, u8 local_port,
 	int err;
 
 	attrs.split = split;
+	attrs.lanes = lanes;
 	attrs.flavour = flavour;
 	attrs.phys.port_number = port_number;
 	attrs.phys.split_subport_number = split_port_subnumber;
diff --git a/include/net/devlink.h b/include/net/devlink.h
index 96fe5c05f62f..ee088cead80a 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -66,6 +66,7 @@ struct devlink_port_pci_vf_attrs {
 
 struct devlink_port_attrs {
 	u8 split:1;
+	u32 lanes;
 	enum devlink_port_flavour flavour;
 	struct netdev_phys_item_id switch_id;
 	union {
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 08563e6a424d..806c6a437fa2 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -451,6 +451,8 @@ enum devlink_attr {
 	DEVLINK_ATTR_TRAP_POLICER_RATE,			/* u64 */
 	DEVLINK_ATTR_TRAP_POLICER_BURST,		/* u64 */
 
+	DEVLINK_ATTR_PORT_LANES,			/* u32 */
+
 	/* add new attributes above here, update the policy in devlink.c */
 
 	__DEVLINK_ATTR_MAX,
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 6a783e712794..ce82629b7386 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -526,6 +526,10 @@ static int devlink_nl_port_attrs_put(struct sk_buff *msg,
 
 	if (!devlink_port->attrs_set)
 		return 0;
+	if (attrs->lanes) {
+		if (nla_put_u32(msg, DEVLINK_ATTR_PORT_LANES, attrs->lanes))
+			return -EMSGSIZE;
+	}
 	if (nla_put_u16(msg, DEVLINK_ATTR_PORT_FLAVOUR, attrs->flavour))
 		return -EMSGSIZE;
 	switch (devlink_port->attrs.flavour) {
@@ -7405,6 +7409,9 @@ static int __devlink_port_attrs_set(struct devlink_port *devlink_port,
  *					   user, for example the front panel
  *			                   port number
  *			     @split: indicates if this is split port
+ *			     @lanes: maximum number of lanes the port supports.
+ *				     0 value is not passed to netlink and valid
+ *				     number is a power of 2.
  *			     @split_subport_number: if the port is split, this
  *			                            is the number of subport.
  *			     @switch_id: if the port is part of switch, this is
-- 
2.20.1