Merge branch 'support-setting-lanes-via-ethtool'

Danielle Ratson says:

====================
Support setting lanes via ethtool

Some speeds can be achieved with different number of lanes. For example,
100Gbps can be achieved using two lanes of 50Gbps or four lanes of
25Gbps. This patchset adds a new selector that allows ethtool to
advertise link modes according to their number of lanes and also force a
specific number of lanes when autonegotiation is off.

Advertising all link modes with a speed of 100Gbps that use two lanes:

$ ethtool -s swp1 speed 100000 lanes 2 autoneg on

Forcing a speed of 100Gbps using four lanes:

$ ethtool -s swp1 speed 100000 lanes 4 autoneg off
====================

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

Documentation/networking/ethtool-netlink.rst

@@ -431,16 +431,17 @@ Request contents:
   ``ETHTOOL_A_LINKMODES_SPEED``               u32     link speed (Mb/s)
   ``ETHTOOL_A_LINKMODES_DUPLEX``              u8      duplex mode
   ``ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG``    u8      Master/slave port mode
+  ``ETHTOOL_A_LINKMODES_LANES``               u32     lanes
   ==========================================  ======  ==========================
 
 ``ETHTOOL_A_LINKMODES_OURS`` bit set allows setting advertised link modes. If
 autonegotiation is on (either set now or kept from before), advertised modes
 are not changed (no ``ETHTOOL_A_LINKMODES_OURS`` attribute) and at least one
-of speed and duplex is specified, kernel adjusts advertised modes to all
-supported modes matching speed, duplex or both (whatever is specified). This
-autoselection is done on ethtool side with ioctl interface, netlink interface
-is supposed to allow requesting changes without knowing what exactly kernel
-supports.
+of speed, duplex and lanes is specified, kernel adjusts advertised modes to all
+supported modes matching speed, duplex, lanes or all (whatever is specified).
+This autoselection is done on ethtool side with ioctl interface, netlink
+interface is supposed to allow requesting changes without knowing what exactly
+kernel supports.
 
 
 LINKSTATE_GET

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

@@ -328,15 +328,16 @@ struct mlxsw_sp_port_type_speed_ops {
 					 u32 ptys_eth_proto,
 					 struct ethtool_link_ksettings *cmd);
 	void (*from_ptys_link)(struct mlxsw_sp *mlxsw_sp, u32 ptys_eth_proto,
-			       u8 width, unsigned long *mode);
+			       unsigned long *mode);
 	u32 (*from_ptys_speed)(struct mlxsw_sp *mlxsw_sp, u32 ptys_eth_proto);
-	void (*from_ptys_speed_duplex)(struct mlxsw_sp *mlxsw_sp,
-				       bool carrier_ok, u32 ptys_eth_proto,
-				       struct ethtool_link_ksettings *cmd);
+	void (*from_ptys_link_mode)(struct mlxsw_sp *mlxsw_sp,
+				    bool carrier_ok, u32 ptys_eth_proto,
+				    struct ethtool_link_ksettings *cmd);
 	int (*ptys_max_speed)(struct mlxsw_sp_port *mlxsw_sp_port, u32 *p_max_speed);
-	u32 (*to_ptys_advert_link)(struct mlxsw_sp *mlxsw_sp, u8 width,
+	u32 (*to_ptys_advert_link)(struct mlxsw_sp *mlxsw_sp,
+				   const struct ethtool_link_ksettings *cmd);
+	u32 (*to_ptys_speed_lanes)(struct mlxsw_sp *mlxsw_sp, u8 width,
 				   const struct ethtool_link_ksettings *cmd);
-	u32 (*to_ptys_speed)(struct mlxsw_sp *mlxsw_sp, u8 width, u32 speed);
 	void (*reg_ptys_eth_pack)(struct mlxsw_sp *mlxsw_sp, char *payload,
 				  u8 local_port, u32 proto_admin, bool autoneg);
 	void (*reg_ptys_eth_unpack)(struct mlxsw_sp *mlxsw_sp, char *payload,