igb: add support for reporting 5GT/s during probe on PCIe Gen2

This change corrects the fact that we were not reporting Gen2 link speeds
when we were in fact connected at Gen2 rates.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/igb/e1000_defines.h

@@ -610,11 +610,7 @@
 #define IGP_LED3_MODE           0x07000000
 
 /* PCI/PCI-X/PCI-EX Config space */
-#define PCIE_LINK_STATUS             0x12
 #define PCIE_DEVICE_CONTROL2         0x28
-
-#define PCIE_LINK_WIDTH_MASK         0x3F0
-#define PCIE_LINK_WIDTH_SHIFT        4
 #define PCIE_DEVICE_CONTROL2_16ms    0x0005
 
 #define PHY_REVISION_MASK      0xFFFFFFF0

drivers/net/igb/e1000_mac.c

@@ -53,17 +53,30 @@ s32 igb_get_bus_info_pcie(struct e1000_hw *hw)
 	u16 pcie_link_status;
 
 	bus->type = e1000_bus_type_pci_express;
-	bus->speed = e1000_bus_speed_2500;
 
 	ret_val = igb_read_pcie_cap_reg(hw,
-					  PCIE_LINK_STATUS,
-					  &pcie_link_status);
-	if (ret_val)
+					PCI_EXP_LNKSTA,
+					&pcie_link_status);
+	if (ret_val) {
 		bus->width = e1000_bus_width_unknown;
-	else
+		bus->speed = e1000_bus_speed_unknown;
+	} else {
+		switch (pcie_link_status & PCI_EXP_LNKSTA_CLS) {
+		case PCI_EXP_LNKSTA_CLS_2_5GB:
+			bus->speed = e1000_bus_speed_2500;
+			break;
+		case PCI_EXP_LNKSTA_CLS_5_0GB:
+			bus->speed = e1000_bus_speed_5000;
+			break;
+		default:
+			bus->speed = e1000_bus_speed_unknown;
+			break;
+		}
+
 		bus->width = (enum e1000_bus_width)((pcie_link_status &
-						     PCIE_LINK_WIDTH_MASK) >>
-						     PCIE_LINK_WIDTH_SHIFT);
+						     PCI_EXP_LNKSTA_NLW) >>
+						     PCI_EXP_LNKSTA_NLW_SHIFT);
+	}
 
 	reg = rd32(E1000_STATUS);
 	bus->func = (reg & E1000_STATUS_FUNC_MASK) >> E1000_STATUS_FUNC_SHIFT;

drivers/net/igb/igb_main.c

@@ -1638,6 +1638,7 @@ static int __devinit igb_probe(struct pci_dev *pdev,
 	dev_info(&pdev->dev, "%s: (PCIe:%s:%s) %pM\n",
 		 netdev->name,
 		 ((hw->bus.speed == e1000_bus_speed_2500) ? "2.5Gb/s" :
+		  (hw->bus.speed == e1000_bus_speed_5000) ? "5.0Gb/s" :
 		                                            "unknown"),
 		 ((hw->bus.width == e1000_bus_width_pcie_x4) ? "Width x4" :
 		  (hw->bus.width == e1000_bus_width_pcie_x2) ? "Width x2" :

include/linux/pci_regs.h

@@ -442,7 +442,10 @@
 #define  PCI_EXP_LNKCTL_LABIE	0x0800	/* Lnk Autonomous Bandwidth Interrupt Enable */
 #define PCI_EXP_LNKSTA		18	/* Link Status */
 #define  PCI_EXP_LNKSTA_CLS	0x000f	/* Current Link Speed */
+#define  PCI_EXP_LNKSTA_CLS_2_5GB 0x01	/* Current Link Speed 2.5GT/s */
+#define  PCI_EXP_LNKSTA_CLS_5_0GB 0x02	/* Current Link Speed 5.0GT/s */
 #define  PCI_EXP_LNKSTA_NLW	0x03f0	/* Nogotiated Link Width */
+#define  PCI_EXP_LNKSTA_NLW_SHIFT 4	/* start of NLW mask in link status */
 #define  PCI_EXP_LNKSTA_LT	0x0800	/* Link Training */
 #define  PCI_EXP_LNKSTA_SLC	0x1000	/* Slot Clock Configuration */
 #define  PCI_EXP_LNKSTA_DLLLA	0x2000	/* Data Link Layer Link Active */