powerpc/pseries: Define PCI bus speed for Gen4 and Gen5

Update bus speed definition for PCI Gen4 and 5.
Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201130152949.26467-1-fbarrat@linux.ibm.com

arch/powerpc/platforms/pseries/pci.c

@@ -290,6 +290,25 @@ static void fixup_winbond_82c105(struct pci_dev* dev)
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND, PCI_DEVICE_ID_WINBOND_82C105,
 			 fixup_winbond_82c105);
 
+static enum pci_bus_speed prop_to_pci_speed(u32 prop)
+{
+	switch (prop) {
+	case 0x01:
+		return PCIE_SPEED_2_5GT;
+	case 0x02:
+		return PCIE_SPEED_5_0GT;
+	case 0x04:
+		return PCIE_SPEED_8_0GT;
+	case 0x08:
+		return PCIE_SPEED_16_0GT;
+	case 0x10:
+		return PCIE_SPEED_32_0GT;
+	default:
+		pr_debug("Unexpected PCI link speed property value\n");
+		return PCI_SPEED_UNKNOWN;
+	}
+}
+
 int pseries_root_bridge_prepare(struct pci_host_bridge *bridge)
 {
 	struct device_node *dn, *pdn;
@@ -322,35 +341,7 @@ int pseries_root_bridge_prepare(struct pci_host_bridge *bridge)
 		return 0;
 	}
 
-	switch (pcie_link_speed_stats[0]) {
-	case 0x01:
-		bus->max_bus_speed = PCIE_SPEED_2_5GT;
-		break;
-	case 0x02:
-		bus->max_bus_speed = PCIE_SPEED_5_0GT;
-		break;
-	case 0x04:
-		bus->max_bus_speed = PCIE_SPEED_8_0GT;
-		break;
-	default:
-		bus->max_bus_speed = PCI_SPEED_UNKNOWN;
-		break;
-	}
-
-	switch (pcie_link_speed_stats[1]) {
-	case 0x01:
-		bus->cur_bus_speed = PCIE_SPEED_2_5GT;
-		break;
-	case 0x02:
-		bus->cur_bus_speed = PCIE_SPEED_5_0GT;
-		break;
-	case 0x04:
-		bus->cur_bus_speed = PCIE_SPEED_8_0GT;
-		break;
-	default:
-		bus->cur_bus_speed = PCI_SPEED_UNKNOWN;
-		break;
-	}
-
+	bus->max_bus_speed = prop_to_pci_speed(pcie_link_speed_stats[0]);
+	bus->cur_bus_speed = prop_to_pci_speed(pcie_link_speed_stats[1]);
 	return 0;
 }