net/i40e: fix MAC loopback on X722

[ upstream commit 6355ff768b0b5871cc82a69194b376db39ee6e9c ]

If enabling MAC loopback mode on X722 NIC, transmitted packets are not
seen in the receive queue. The root cause is using wrong loopback mode
bits. Correct it according to the X722 datasheet.

Fixes: 3a838ab ("net/i40e: support MAC loopback")
Fixes: 5712e64 ("net/i40e: revert enhancing loopback AQ command")

Signed-off-by: Wenjing Qiao <wenjing.qiao@intel.com>
Tested-by: Dukai Yuan <dukaix.yuan@intel.com>

drivers/net/i40e/i40e_ethdev.c

@@ -2520,10 +2520,21 @@ i40e_dev_start(struct rte_eth_dev *dev)
 		}
 	}
 
+	/* Disable mac loopback mode */
+	if (dev->data->dev_conf.lpbk_mode == I40E_AQ_LB_MODE_NONE) {
+		ret = i40e_aq_set_lb_modes(hw, I40E_AQ_LB_MODE_NONE, NULL);
+		if (ret != I40E_SUCCESS) {
+			PMD_DRV_LOG(ERR, "fail to set loopback link");
+			goto tx_err;
+		}
+	}
+
 	/* Enable mac loopback mode */
-	if (dev->data->dev_conf.lpbk_mode == I40E_AQ_LB_MODE_NONE ||
-	    dev->data->dev_conf.lpbk_mode == I40E_AQ_LB_PHY_LOCAL) {
-		ret = i40e_aq_set_lb_modes(hw, dev->data->dev_conf.lpbk_mode, NULL);
+	if (dev->data->dev_conf.lpbk_mode == I40E_AQ_LB_MODE_EN) {
+		if (hw->mac.type == I40E_MAC_X722)
+			ret = i40e_aq_set_lb_modes(hw, I40E_AQ_LB_MAC_LOCAL_X722, NULL);
+		else
+			ret = i40e_aq_set_lb_modes(hw, I40E_AQ_LB_MAC, NULL);
 		if (ret != I40E_SUCCESS) {
 			PMD_DRV_LOG(ERR, "fail to set loopback link");
 			goto tx_err;

drivers/net/i40e/i40e_ethdev.h

@@ -47,6 +47,9 @@
 #define I40E_MAX_VF               128
 /*flag of no loopback*/
 #define I40E_AQ_LB_MODE_NONE	  0x0
+#define I40E_AQ_LB_MODE_EN	  0x01
+#define I40E_AQ_LB_MAC		  0x01
+#define I40E_AQ_LB_MAC_LOCAL_X722 0x04
 /*
  * vlan_id is a 12 bit number.
  * The VFTA array is actually a 4096 bit array, 128 of 32bit elements.