i40e: Populate and check pci bus speed and width

Call i40e_set_pci_config_data from probe, then check that
we are in a 8GT/s x8 PCIe slot and send a warning if we are not.

Change-Id: I62815c574cee50d2787c50bbe956dde7a7a75a11
Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_common.c

@@ -2029,3 +2029,47 @@ i40e_status i40e_set_filter_control(struct i40e_hw *hw,
 
 	return 0;
 }
+/**
+ * i40e_set_pci_config_data - store PCI bus info
+ * @hw: pointer to hardware structure
+ * @link_status: the link status word from PCI config space
+ *
+ * Stores the PCI bus info (speed, width, type) within the i40e_hw structure
+ **/
+void i40e_set_pci_config_data(struct i40e_hw *hw, u16 link_status)
+{
+	hw->bus.type = i40e_bus_type_pci_express;
+
+	switch (link_status & PCI_EXP_LNKSTA_NLW) {
+	case PCI_EXP_LNKSTA_NLW_X1:
+		hw->bus.width = i40e_bus_width_pcie_x1;
+		break;
+	case PCI_EXP_LNKSTA_NLW_X2:
+		hw->bus.width = i40e_bus_width_pcie_x2;
+		break;
+	case PCI_EXP_LNKSTA_NLW_X4:
+		hw->bus.width = i40e_bus_width_pcie_x4;
+		break;
+	case PCI_EXP_LNKSTA_NLW_X8:
+		hw->bus.width = i40e_bus_width_pcie_x8;
+		break;
+	default:
+		hw->bus.width = i40e_bus_width_unknown;
+		break;
+	}
+
+	switch (link_status & PCI_EXP_LNKSTA_CLS) {
+	case PCI_EXP_LNKSTA_CLS_2_5GB:
+		hw->bus.speed = i40e_bus_speed_2500;
+		break;
+	case PCI_EXP_LNKSTA_CLS_5_0GB:
+		hw->bus.speed = i40e_bus_speed_5000;
+		break;
+	case PCI_EXP_LNKSTA_CLS_8_0GB:
+		hw->bus.speed = i40e_bus_speed_8000;
+		break;
+	default:
+		hw->bus.speed = i40e_bus_speed_unknown;
+		break;
+	}
+}

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -7369,6 +7369,7 @@ static int i40e_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	struct i40e_pf *pf;
 	struct i40e_hw *hw;
 	static u16 pfs_found;
+	u16 link_status;
 	int err = 0;
 	u32 len;
 
@@ -7603,6 +7604,28 @@ static int i40e_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	mod_timer(&pf->service_timer,
 		  round_jiffies(jiffies + pf->service_timer_period));
 
+	/* Get the negotiated link width and speed from PCI config space */
+	pcie_capability_read_word(pf->pdev, PCI_EXP_LNKSTA, &link_status);
+
+	i40e_set_pci_config_data(hw, link_status);
+
+	dev_info(&pdev->dev, "PCI Express: %s %s\n",
+		(hw->bus.speed == i40e_bus_speed_8000 ? "Speed 8.0GT/s" :
+		 hw->bus.speed == i40e_bus_speed_5000 ? "Speed 5.0GT/s" :
+		 hw->bus.speed == i40e_bus_speed_2500 ? "Speed 2.5GT/s" :
+		 "Unknown"),
+		(hw->bus.width == i40e_bus_width_pcie_x8 ? "Width x8" :
+		 hw->bus.width == i40e_bus_width_pcie_x4 ? "Width x4" :
+		 hw->bus.width == i40e_bus_width_pcie_x2 ? "Width x2" :
+		 hw->bus.width == i40e_bus_width_pcie_x1 ? "Width x1" :
+		 "Unknown"));
+
+	if (hw->bus.width < i40e_bus_width_pcie_x8 ||
+	    hw->bus.speed < i40e_bus_speed_8000) {
+		dev_warn(&pdev->dev, "PCI-Express bandwidth available for this device may be insufficient for optimal performance.\n");
+		dev_warn(&pdev->dev, "Please move the device to a different PCI-e link with more lanes and/or higher transfer rate.\n");
+	}
+
 	return 0;
 
 	/* Unwind what we've done if something failed in the setup */

drivers/net/ethernet/intel/i40e/i40e_prototype.h

@@ -215,6 +215,7 @@ i40e_status i40e_read_nvm_buffer(struct i40e_hw *hw, u16 offset,
 					   u16 *words, u16 *data);
 i40e_status i40e_validate_nvm_checksum(struct i40e_hw *hw,
 						 u16 *checksum);
+void i40e_set_pci_config_data(struct i40e_hw *hw, u16 link_status);
 
 /* prototype for functions used for SW locks */