[net 10/13] net/mlx5e: Fix a bug in turning off FEC policy in unsupported speeds

[Saeed Mahameed]

From: Shay Agroskin <sha...@mellanox.com>

Some speeds don't support turning FEC policy off. In case a requested
FEC policy is not supported for a speed (including current speed), its new
FEC policy would be:
        no FEC - if disabling FEC is supported for that speed
        unchanged - else

Fixes: 2095b2641477 ("net/mlx5e: Add port FEC get/set functions")
Signed-off-by: Shay Agroskin <sha...@mellanox.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
---
 .../net/ethernet/mellanox/mlx5/core/en/port.c | 28 ++++++++-----------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/port.c 
b/drivers/net/ethernet/mellanox/mlx5/core/en/port.c
index 023dc4bccd28..c16351eb9e54 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/port.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/port.c
@@ -394,12 +394,12 @@ int mlx5e_get_fec_mode(struct mlx5_core_dev *dev, u32 
*fec_mode_active,
 
 int mlx5e_set_fec_mode(struct mlx5_core_dev *dev, u8 fec_policy)
 {
+       u8 fec_policy_nofec = BIT(MLX5E_FEC_NOFEC);
        bool fec_mode_not_supp_in_speed = false;
-       u8 no_fec_policy = BIT(MLX5E_FEC_NOFEC);
        u32 out[MLX5_ST_SZ_DW(pplm_reg)] = {};
        u32 in[MLX5_ST_SZ_DW(pplm_reg)] = {};
        int sz = MLX5_ST_SZ_BYTES(pplm_reg);
-       u32 current_fec_speed;
+       u8 fec_policy_auto = 0;
        u8 fec_caps = 0;
        int err;
        int i;
@@ -415,23 +415,19 @@ int mlx5e_set_fec_mode(struct mlx5_core_dev *dev, u8 
fec_policy)
        if (err)
                return err;
 
-       err = mlx5e_port_linkspeed(dev, &current_fec_speed);
-       if (err)
-               return err;
+       MLX5_SET(pplm_reg, out, local_port, 1);
 
-       memset(in, 0, sz);
-       MLX5_SET(pplm_reg, in, local_port, 1);
-       for (i = 0; i < MLX5E_FEC_SUPPORTED_SPEEDS && !!fec_policy; i++) {
+       for (i = 0; i < MLX5E_FEC_SUPPORTED_SPEEDS; i++) {
                mlx5e_get_fec_cap_field(out, &fec_caps, 
fec_supported_speeds[i]);
-               /* policy supported for link speed */
-               if (!!(fec_caps & fec_policy)) {
-                       mlx5e_fec_admin_field(in, &fec_policy, 1,
+               /* policy supported for link speed, or policy is auto */
+               if (fec_caps & fec_policy || fec_policy == fec_policy_auto) {
+                       mlx5e_fec_admin_field(out, &fec_policy, 1,
                                              fec_supported_speeds[i]);
                } else {
-                       if (fec_supported_speeds[i] == current_fec_speed)
-                               return -EOPNOTSUPP;
-                       mlx5e_fec_admin_field(in, &no_fec_policy, 1,
-                                             fec_supported_speeds[i]);
+                       /* turn off FEC if supported. Else, leave it the same */
+                       if (fec_caps & fec_policy_nofec)
+                               mlx5e_fec_admin_field(out, &fec_policy_nofec, 1,
+                                                     fec_supported_speeds[i]);
                        fec_mode_not_supp_in_speed = true;
                }
        }
@@ -441,5 +437,5 @@ int mlx5e_set_fec_mode(struct mlx5_core_dev *dev, u8 
fec_policy)
                              "FEC policy 0x%x is not supported for some 
speeds",
                              fec_policy);
 
-       return mlx5_core_access_reg(dev, in, sz, out, sz, MLX5_REG_PPLM, 0, 1);
+       return mlx5_core_access_reg(dev, out, sz, out, sz, MLX5_REG_PPLM, 0, 1);
 }
-- 
2.19.1