X-Git-Url: http://plrg.eecs.uci.edu/git/?p=firefly-linux-kernel-4.4.55.git;a=blobdiff_plain;f=drivers%2Fof%2Fof_pci.c;h=038c0ec1b0c523b6d2a191f1476d9684efc270c7;hp=b1449f71601cb257f1057b77c217a943da92cab8;hb=d776fdb776681cd013be513ba70ffa51d934f19d;hpb=3e5050e60e3b51e32940926ccb4aa5965f618306

diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index b1449f71601c..038c0ec1b0c5 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -118,6 +118,27 @@ int of_get_pci_domain_nr(struct device_node *node)
 }
 EXPORT_SYMBOL_GPL(of_get_pci_domain_nr);
 
+/**
+ * This function will try to find the limitation of link speed by finding
+ * a property called "max-link-speed" of the given device node.
+ *
+ * @node: device tree node with the max link speed information
+ *
+ * Returns the associated max link speed from DT, or a negative value if the
+ * required property is not found or is invalid.
+ */
+int of_pci_get_max_link_speed(struct device_node *node)
+{
+	u32 max_link_speed;
+
+	if (of_property_read_u32(node, "max-link-speed", &max_link_speed) ||
+	    max_link_speed > 4)
+		return -EINVAL;
+
+	return max_link_speed;
+}
+EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed);
+
 /**
  * of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only
  *                           is present and valid