net/mlx5e: Update xoff formula

Set minimum speed in xoff threshold formula to 40Gbps

Fixes: 0696d60853d5 ("net/mlx5e: Receive buffer configuration")
Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
index eac245a..f00de0c 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
@@ -122,7 +122,9 @@ out:
        return err;
 }
 
-/* xoff = ((301+2.16 * len [m]) * speed [Gbps] + 2.72 MTU [B]) */
+/* xoff = ((301+2.16 * len [m]) * speed [Gbps] + 2.72 MTU [B])
+ * minimum speed value is 40Gbps
+ */
 static u32 calculate_xoff(struct mlx5e_priv *priv, unsigned int mtu)
 {
        u32 speed;
@@ -130,10 +132,9 @@ static u32 calculate_xoff(struct mlx5e_priv *priv, unsigned int mtu)
        int err;
 
        err = mlx5e_port_linkspeed(priv->mdev, &speed);
-       if (err) {
-               mlx5_core_warn(priv->mdev, "cannot get port speed\n");
-               return 0;
-       }
+       if (err)
+               speed = SPEED_40000;
+       speed = max_t(u32, speed, SPEED_40000);
 
        xoff = (301 + 216 * priv->dcbx.cable_len / 100) * speed / 1000 + 272 * mtu / 100;