From: Tal Gilboa <talgi@mellanox.com>
Date: Fri, 30 Mar 2018 09:01:51 -0500
Subject: net/mlx5e: Use pcie_bandwidth_available() to compute bandwidth
Patch-mainline: v4.17-rc1
Git-commit: 33523a361307c097a8a23f3549cb485db5fba6c5
References: bsc#1103990 FATE#326006

Use the new pci_bandwidth_available() function to calculate maximum
available bandwidth through the PCI chain instead of computing it ourselves
with mlx5e_get_pci_bw().

This is used to detect when the device is capable of more bandwidth than is
available in the current slot.  The driver may adjust compression settings
accordingly.

Note that pci_bandwidth_available() accounts for PCIe encoding overhead, so
it is more accurate than mlx5e_get_pci_bw() was.

Signed-off-by: Tal Gilboa <talgi@mellanox.com>
[bhelgaas: remove mlx5e_get_pci_bw() wrapper altogether]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c |   36 +---------------------
 1 file changed, 3 insertions(+), 33 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -4033,45 +4033,15 @@ void mlx5e_build_default_indir_rqt(u32 *
 		indirection_rqt[i] = i % num_channels;
 }
 
-static int mlx5e_get_pci_bw(struct mlx5_core_dev *mdev, u32 *pci_bw)
-{
-	enum pcie_link_width width;
-	enum pci_bus_speed speed;
-	int err = 0;
-
-	err = pcie_get_minimum_link(mdev->pdev, &speed, &width);
-	if (err)
-		return err;
-
-	if (speed == PCI_SPEED_UNKNOWN || width == PCIE_LNK_WIDTH_UNKNOWN)
-		return -EINVAL;
-
-	switch (speed) {
-	case PCIE_SPEED_2_5GT:
-		*pci_bw = 2500 * width;
-		break;
-	case PCIE_SPEED_5_0GT:
-		*pci_bw = 5000 * width;
-		break;
-	case PCIE_SPEED_8_0GT:
-		*pci_bw = 8000 * width;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
 static bool slow_pci_heuristic(struct mlx5_core_dev *mdev)
 {
 	u32 link_speed = 0;
 	u32 pci_bw = 0;
 
 	mlx5e_get_max_linkspeed(mdev, &link_speed);
-	mlx5e_get_pci_bw(mdev, &pci_bw);
-	mlx5_core_dbg_once(mdev, "Max link speed = %d, PCI BW = %d\n",
-			   link_speed, pci_bw);
+	pci_bw = pcie_bandwidth_available(mdev->pdev, NULL, NULL, NULL);
+	mlx5_core_dbg(mdev, "Max link speed = %d, PCI BW = %d\n",
+		      link_speed, pci_bw);
 
 #define MLX5E_SLOW_PCI_RATIO (2)