From: Amit Cohen <amitc@mellanox.com>
Date: Wed, 29 May 2019 10:59:45 +0300
Subject: mlxsw: spectrum: Prevent force of 56G
Patch-mainline: v5.2-rc3
Git-commit: 275e928f19117d22f6d26dee94548baf4041b773
References: git-fixes

Force of 56G is not supported by hardware in Ethernet devices. This
configuration fails with a bad parameter error from firmware.

Add check of this case. Instead of trying to set 56G with autoneg off,
return a meaningful error.

Fixes: 56ade8fe3fe1 ("mlxsw: spectrum: Add initial support for Spectrum ASIC")
Signed-off-by: Amit Cohen <amitc@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -2492,6 +2492,10 @@ mlxsw_sp_port_set_link_ksettings(struct
 	mlxsw_reg_ptys_eth_unpack(ptys_pl, &eth_proto_cap, NULL, NULL);
 
 	autoneg = cmd->base.autoneg == AUTONEG_ENABLE;
+	if (!autoneg && cmd->base.speed == SPEED_56000) {
+		netdev_err(dev, "56G not supported with autoneg off\n");
+		return -EINVAL;
+	}
 	eth_proto_new = autoneg ?
 		mlxsw_sp_to_ptys_advert_link(cmd) :
 		mlxsw_sp_to_ptys_speed(cmd->base.speed);