qed: Do not add VLAN 0 tag to untagged frames in multi-function mode.

In certain multi-function switch dependent modes, firmware adds vlan tag 0
to the untagged frames. This leads to double tagging for the traffic
if the dcbx is enabled, which is not the desired behavior. To avoid this,
driver needs to set "dcb_dont_add_vlan0" flag.

Fixes: cac6f691 ("qed: Add support for Unified Fabric Port")
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Tomer Tayar <Tomer.Tayar@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qed/qed_dcbx.c

@@ -190,6 +190,7 @@ qed_dcbx_dp_protocol(struct qed_hwfn *p_hwfn, struct qed_dcbx_results *p_data)
 
 static void
 qed_dcbx_set_params(struct qed_dcbx_results *p_data,
+		    struct qed_hwfn *p_hwfn,
 		    struct qed_hw_info *p_info,
 		    bool enable,
 		    u8 prio,
@@ -206,6 +207,11 @@ qed_dcbx_set_params(struct qed_dcbx_results *p_data,
 	else
 		p_data->arr[type].update = DONT_UPDATE_DCB_DSCP;
 
+	/* Do not add vlan tag 0 when DCB is enabled and port in UFP/OV mode */
+	if ((test_bit(QED_MF_8021Q_TAGGING, &p_hwfn->cdev->mf_bits) ||
+	     test_bit(QED_MF_8021AD_TAGGING, &p_hwfn->cdev->mf_bits)))
+		p_data->arr[type].dont_add_vlan0 = true;
+
 	/* QM reconf data */
 	if (p_info->personality == personality)
 		qed_hw_info_set_offload_tc(p_info, tc);
@@ -231,7 +237,7 @@ qed_dcbx_update_app_info(struct qed_dcbx_results *p_data,
 
 		personality = qed_dcbx_app_update[i].personality;
 
-		qed_dcbx_set_params(p_data, p_info, enable,
+		qed_dcbx_set_params(p_data, p_hwfn, p_info, enable,
 				    prio, tc, type, personality);
 	}
 }
@@ -954,6 +960,7 @@ static void qed_dcbx_update_protocol_data(struct protocol_dcb_data *p_data,
 	p_data->dcb_enable_flag = p_src->arr[type].enable;
 	p_data->dcb_priority = p_src->arr[type].priority;
 	p_data->dcb_tc = p_src->arr[type].tc;
+	p_data->dcb_dont_add_vlan0 = p_src->arr[type].dont_add_vlan0;
 }
 
 /* Set pf update ramrod command params */

drivers/net/ethernet/qlogic/qed/qed_dcbx.h

@@ -55,6 +55,7 @@ struct qed_dcbx_app_data {
 	u8 update;		/* Update indication */
 	u8 priority;		/* Priority */
 	u8 tc;			/* Traffic Class */
+	bool dont_add_vlan0;	/* Do not insert a vlan tag with id 0 */
 };
 
 #define QED_DCBX_VERSION_DISABLED       0