Add trunking support and initial L2 setup

rtl837x_regs.h

@@ -98,6 +98,15 @@
 #define RTL837x_L2_TBL_CTRL	0x53d4
 #define RTL837x_PVID_BASE_REG	0x4e1c
 
+/*
+ * Egress / ingress filtering
+ */
+// 2 bits per port: allow tagged (01) / untagged (10) and all (00)
+#define RTL837x_REG_INGRESS	0x4e10
+#define INGR_ALLOW_TAGGED 1
+#define INGR_ALLOW_UNTAGGED 2
+#define INGR_ALLOW_ALL 0
+
 /*
  * Mirroring
  */