static void b53_set_forwarding(struct b53_device *dev, int enable)
 {
+       struct dsa_switch *ds = dev->ds;
        u8 mgmt;
 
        b53_read8(dev, B53_CTRL_PAGE, B53_SWITCH_MODE, &mgmt);
                mgmt &= ~SM_SW_FWD_EN;
 
        b53_write8(dev, B53_CTRL_PAGE, B53_SWITCH_MODE, mgmt);
+
+       /* Include IMP port in dumb forwarding mode when no tagging protocol is
+        * set
+        */
+       if (ds->ops->get_tag_protocol(ds) == DSA_TAG_PROTO_NONE) {
+               b53_read8(dev, B53_CTRL_PAGE, B53_SWITCH_CTRL, &mgmt);
+               mgmt |= B53_MII_DUMB_FWDG_EN;
+               b53_write8(dev, B53_CTRL_PAGE, B53_SWITCH_CTRL, mgmt);
+       }
 }
 
 static void b53_enable_vlan(struct b53_device *dev, bool enable)
 
 #define  B53_UC_FWD_EN                 BIT(6)
 #define  B53_MC_FWD_EN                 BIT(7)
 
+/* Switch control (8 bit) */
+#define B53_SWITCH_CTRL                        0x22
+#define  B53_MII_DUMB_FWDG_EN          BIT(6)
+
 /* (16 bit) */
 #define B53_UC_FLOOD_MASK              0x32
 #define B53_MC_FLOOD_MASK              0x34